CN102625874A - Apparatus for variably adjusting the control times of gas exchange valves in an internal combustion engine - Google Patents

Abstract

The invention relates to an apparatus (10) for variably adjusting the control times of gas exchange valves (9a, b) in an internal combustion engine (1). Said apparatus (10) comprises a driving element (22), an output element (23), at least one pressure chamber (35, 36), a pressurized medium supply device (37), and at least one pressure accumulator (43). The pressurized medium supply device (37) allows pressurized medium to be fed to or discharged from the at least one pressure chamber (35, 36). A phase angle of the output element (23) relative to the driving element (22) can be changed by supplying or discharging pressurized medium to or from the pressure chamber (35, 36). The pressure accumulator (43) encompasses a movable element (45) that has a first pressure surface (47) which partially delimits a storage space (49). The storage space (49) is connected to the pressurized medium supply device (37). The movable element (45) can be moved against the force of an energy store (46) by pressurizing the storage space (49).

Description

Be used for the gas exchange valves of internal combustion engine port timing is carried out the device of variable adjustment

Technical field

The present invention relates to a kind of device that is used for the gas exchange valves of internal combustion engine port timing is carried out variable adjustment, this device has driving component, driven member, at least one pressure chamber, pressure medium supply unit and at least one accumulator, wherein; By pressure medium supply unit can at least one pressure chamber's discharge pressure medium or from this pressure chamber the head pressure medium, wherein, through to pressure chamber's discharge pressure medium or from the pressure chamber head pressure medium; Can change the phase place of driven member with respect to driving component; Wherein, accumulator has displaceable element, and this displaceable element has first pressure side that partly defines reserve chamber; Wherein, Reserve chamber is connected with pressure medium supply unit, wherein, through the pressurization to reserve chamber displaceable element is moved against trying hard to recommend of accumulator.

Background technique

In the internal-combustion engine in modern times, use the device that the scavenging air valve port timing is carried out variable adjustment, so that the phase relationship between bent axle and the camshaft is being constituted between position and the maximum slow position the most very early in the morning changeably in the angular range that limits.This device generally includes regulating device, regulating device by the bent axle transmission and with its transmission of torque to camshaft.At this, constitute the hydraulic servo drive unit in the inside of regulating device, this hydraulic servo drive unit can influence the phase place between bent axle and the camshaft targetedly.In order to give regulating device supply pressure medium, be provided with pressure medium supply unit.

This device is for example known byEP 1 025 343 B1.This device comprises two rotors that can reverse against each other, and wherein, external rotor is in transmission connection with bent axle and internal rotor is connected with camshaft antitorquely.This device comprises a plurality of cavitys, and wherein, each cavity is divided into the pressure chamber of two relativities by blade.Through to pressure chamber's discharge pressure medium or from the pressure chamber head pressure medium, blade is passed in the inside of pressure chamber, rotor is reversed against each other targetedly and and then camshaft reverse targetedly with respect to bent axle.

To pressure chamber's discharge pressure medium or from the pressure chamber head pressure medium, all control by pressure medium supply unit, this pressure medium supply unit comprises pressure medium pump, fuel tank, control valve and a plurality of pressure medium pipeline.At this, a pressure medium pipeline is connected pressure medium pump with control valve.Each other pressure medium pipeline is connected one of working interface of control valve with the pressure chamber.Pressure medium is taken from the lubricant medium loop of internal-combustion engine usually.

For guaranteeing the function of this device, the pressure in the pressure medium system all must surpass certain numerical value in each operation phase of internal-combustion engine.This point is particularly abnormally dangerous in the idling stage of internal-combustion engine, this be because pressure medium pump by the bent axle transmission and and then system pressure along with the rotating speed of internal-combustion engine rises.The system pressure that is provided by pressure medium pump depends on the pressure medium temperature in addition, and wherein, system pressure descends under the situation that temperature rises.Therefore, pressure medium pump must design as follows, that is, pressure medium pump provides enough system pressures under worst condition, to guarantee enough to adjust apace the phase place of internal rotor with respect to external rotor.Even under worst pressure condition, for example under image height pressure medium temperature and/or the slow-revving situation, also guarantee desired regulating the speed, pressure medium pump must correspondingly design therewith.This point caused using according to the peak demand design of regulating device and the therefore pressure medium pump of excessive setting size during most operation phase of internal-combustion engine.Can use adjustable pressure medium pump as selecting, this adjustable pressure medium pump provides pressure medium as required.The spending that increases under two kinds of situation is having a negative impact aspect cost, structure space demand and the fuel consumption of internal-combustion engine.

US 5,775, disclose the device of another kind of this type among 279 A.In this embodiment, between pressure medium pump and control valve, be provided with the accumulator that is communicated with pressure medium supply unit.This accumulator high stage of system pressure by the pressure medium of annotating.If system pressure descends, so automatic emptying accumulator, pressure medium supply unit provides additional pressure medium thus.Therefore, the adjustment mutually of this device is supported.The shortcoming of this mode of execution is, accumulator is not based on adjustment process at system pressure, and is based on other external circumstances, also is drained under the situation about for example reducing through rotating speed.The pressure support that therefore can supply phase adjustment process subsequently to use is littler and from the pressure medium volume of accumulator still less.Another shortcoming is that pressure medium supply unit can support the pressure maximum of accumulator to be equivalent to just before the phase adjustment process, be in the pressure in the pressure medium supply unit.If engine controlling unit proposes the adjustment requirement to this device under high temperature and slow-speed of revolution situation, the pressure support of accumulator diminishes so, because the system pressure that accumulator is annotated is very little.This point can cause implementing adjustment process or regulate the speed obviously descending.Therefore in this case, pressure medium pump also needs according to following the peak load that produces defective thus to design.

Summary of the invention

The objective of the invention is to, a kind of device that is used for the gas exchange valves of internal combustion engine port timing is carried out variable adjustment is provided, wherein, guarantee in each operation phase of internal-combustion engine under the situation that height is regulated the speed, reliable in function ground adjustment port timing.At this, should be as the application of cancelling the variable pressure medium pump, the oversized dimensions (peak load according to being estimated designs) of cancellation pressure medium pump.

This purpose realizes according to the present invention as follows; Be that displaceable element has second pressure side that at least one partly defines control chamber; Wherein, Through pressurization displaceable element is moved against trying hard to recommend of accumulator, and wherein, flow into control chamber from reserve chamber at the internalized prohibition pressure medium of accumulator to control chamber.

Can be set at this, reserve chamber and control chamber are not interconnected in the inside of accumulator.

Displaceable element for example can constitute pressure piston, and this pressure piston can move against trying hard to recommend of the accumulator that constitutes spring part in the inside of pressurized container.Alternatively, also can use other forms of accumulator, the capsule that the possibility of reversal body of for example being processed by the bullet colloid is perhaps inflated.The structural scheme of the accumulator through having following displaceable element, wherein, this displaceable element partly defines isolated each other chamber, accumulator inside, and these two chambeies can be controlled apart from each other, just by filling and/or emptying.Only if leak, do not have connection between the chamber.So for example can different pressure sources be used for reserve chamber and control chamber are annotated.As selection, also can there be pressure medium to be connected between reserve chamber and the control chamber in accumulator inside.The pressure medium that flows to control chamber can connect in the entering reserve chamber through this pressure medium.But it should be noted that at this and forbid that pressure medium flows conversely from the reserve chamber to the control chamber.This point for example can realize through the pressure medium channel that wherein is provided with in the non-return valve housing of pressure medium pipeline in the pressure piston or accumulator.In this case, the filling of reserve chamber and control chamber is only carried out through the filling to control chamber.If accumulator should emptying, so control chamber is received on the fuel tank.Reserve chamber is emptied in the pressure medium supply unit, is emptied in the fuel tank to the control chamber decompression, and pressure medium overflowing in from the reserve chamber to the control chamber is prevented through safety check.

If be set to: to reserve chamber filling pressure medium displaceable element is moved on the direction identical with pressure medium that control chamber is annotated, control chamber can be supported the filling of reserve chamber so.For this purpose, control chamber during the filling process of reserve chamber equally by the filling pressure medium.Thus, the masterpiece that acts on this pressure piston is used for two pressure sides of pressure piston, stores higher power (spring part receives compression more consumingly) thus in the accumulator.If received that from engine controlling unit instruction supports the phase adjustment process by the accumulator of being annotated, control chamber can be independent of reserve chamber and carries out emptying so.That is to say that reserve chamber is emptied in the pressure medium supply unit and therefore and supports during the phase adjustment process that control chamber is against barometric pressure exhaust in fuel tank.Through suitable design, the exhaust of control chamber can be carried out than the emptying of reserve chamber in pressure medium supply unit quickly.Therefore the whole power that are stored in the accumulator act on reserve chamber through first pressure side.As consequence be, when pressure began at supporting process, depending on the load that acts on accumulator on this time point can be to improve until following coefficient, this coefficient is:

$\frac{A_1+A_2}{{\mathrm{<figure-callout\; label="A"\; filenames="HPA00001140645700011.png"\; state="\{\{state\}\}">A</figure-callout>}}_1}.$

At this, A₁The area and the A that are equivalent to first pressure side₂The area that is equivalent to second pressure side.If for example use spring part as accumulator; As long as pressure does not reach its maximum compressive state, pressure just increases with complete (voll) coefficient

when supporting process begins so.

The present invention is the basis to be described below; Promptly; A kind of device that is used for the gas exchange valves of internal combustion engine port timing is carried out variable adjustment; This device has driving component, driven member, at least one pressure chamber, pressure medium supply unit and at least one accumulator, wherein, by pressure medium supply unit can at least one pressure chamber's discharge pressure medium or from this pressure chamber the head pressure medium; Wherein, Through to pressure chamber's discharge pressure medium or from the pressure chamber head pressure medium, can change the phase place of driven member with respect to driving component, the displaceable element of accumulator at least two formations independently of one another and the chamber that can exert pressure on the movement direction of this element, define.At this, at least one chamber (reserve chamber) connects with pressure medium supply unit and can be emptied in the pressure medium supply unit during the adjustment process mutually.In addition, during to the filling process of reserve chamber equally to during another chamber (control chamber) filling pressure medium and the evacuation procedure at least in reserve chamber than the emptying quickly of this reserve chamber.This point for example can be carried out in fuel tank against barometric pressure.Therefore control chamber is supported filling process as follows, that is, displaceable element is not than to the exert pressure situation deflection more doughtily of medium of control chamber.

Through improving the pressure that is provided by accumulator, accumulator can be stabilized peak value consumption, thereby pressure medium pump can design according to the normal operation of internal-combustion engine.Need not pressure medium pump excessive setting size or adjusted adjusts the phase place reliable in function in order to assurance fast.Additional being improved of regulating the speed of regulating device.As selection, under the identical situation of regulating the speed, regulating device can reduce size.Reduce quality, moment of inertia and cost thus.

In improvement project of the present invention, control chamber can be connected with pressure source or fuel tank during internal combustion engine operation selectively.Pressure source for example can be pressure medium supply unit or its pressure medium pump or separated source, the pressure source of for example servo customer (Servobraucher) (for example servo steering spare).Under second kind of situation, accumulator also can be by filling fully in the operation phase of low system pressure.Select to be connected through control mechanism with having of pressure source or fuel tank, the two-bit triplet selector valve that for example is distributing valve (for example poppet-valve) or Proportional valve (for example guiding valve) form produces.Also can consider two control mechanisms as selecting, wherein, a control mechanism is blocked or the connection of release pressure source-control chamber and the connection of the blocking-up of another control mechanism or release control chamber-fuel tank.Control mechanism for example can be the hydrovalve of eletromagnetic-operating, like selector valve (for example distributing valve or Proportional valve), can remove the safety check etc. of blocking-up.These control mechanisms receive control signal from the engine controlling unit of internal-combustion engine, according to this control signal accumulator are annotated or emptying.Therefore can realize extremely different support policies.Can consider to use the hydraulically operated control mechanism equally.At this, the apply device of control mechanism is communicated with pressure medium supply unit.Automatically switch when the pressure of control mechanism in pressure medium supply unit drops under definite numerical value like this.Obviously reduce thus and regulate spending.

In concrete scheme of the present invention, be set to, control chamber can not detour via customer and just be emptied in the fuel tank.At this, control chamber is preferably against general passing ratio valve of barometric pressure or distributing valve emptying.

In improvement project of the present invention, be provided with following control mechanism, wherein, control chamber can be connected with fuel tank or pressure source by this control mechanism selectively.Control valve for example can constitute selector valve.

In a kind of improvement project that can select else this of the present invention, be provided with following control mechanism; This control mechanism occluding pressure medium under first state flows and the authorized pressure medium flows to reserve chamber and control chamber to pressure medium supply unit from reserve chamber, and this control mechanism is mobile and be connected under situation about not detouring via customer, producing between control chamber and the fuel tank to pressure medium supply unit from reserve chamber at authorized pressure medium under second state.At this, reserve chamber is connected through safety check with control chamber, and wherein, this connection is arranged between control mechanism and the chamber, and wherein, safety check occluding pressure medium is from reserve chamber flowing to control chamber.

Therefore prevent that reserve chamber is communicated with in the stage at internal combustion engine operation with pressure medium supply unit, in the operation phase, do not take place to adjust mutually that however system pressure still descends.Therefore pressure medium volume in the reserve chamber and pressure are remained on the high numerical value.

At this, be provided with following deposit pipeline, this deposit pipeline is connected pressure medium supply unit and is provided with the pilot line that control chamber is connected with pressure source with reserve chamber.In addition, control mechanism can constitute unique selector valve and constitute, and this selector valve has each interface that is used to lay in pipeline, pilot line, control chamber, reserve chamber and fuel tank.Reduce the quantity and the spending of the adjusting during the internal combustion engine operation of parts thus.As selection, control mechanism comprises that at least one is arranged on first selector valve in the pilot line.Control mechanism comprises second selector valve that is arranged in the deposit pipeline in addition.At this, selector valve for example can constitute distributing valve or Proportional valve.As selection, control mechanism can comprise the safety check that can remove blocking-up that is arranged in the deposit pipeline in addition.

What have advantage is, according in the device of the present invention, is provided with safety check between control chamber and the pressure source, and it is blocked from the pressure medium flow of control chamber to the pressure source direction.Therefore, the pressure medium amount that is in the control chamber is lockable, and is connected with fuel tank until it.Thus, even system pressure decline displaceable element also remains on the inflection point and therefore prevents undesirably emptying of reserve chamber.

In improvement project of the present invention, be set to, between reserve chamber and pressure medium supply unit, be provided with safety check, this safety check blocking-up is from the pressure medium flow of pressure medium supply unit towards the reserve chamber direction.Prevent thus: the pressure peak that produces in the regulating device is delivered in the accumulator.Therefore the pressure medium that refluxes from the pressure chamber of regulating device during the pressure peak is supported at safety check, thus, improves the hydraulic pressure rigidity of this device and therefore improves and regulate the speed and improve the transmission of torque of bent axle on camshaft.

Therefore the pressure support of accumulator can activate through switching one or more control mechanism simply.Accumulate in the reserve chamber in the internal-combustion engine phase place keeps constant operation phase at pressure medium volume that this provides.At this, the pressure that is provided by accumulator is according to mode of execution, or being equivalent to real system pressure multiply by until 1+A₂/ A₁Coefficient, or the maximum system pressure that is equivalent to exist during the filling stage multiply by same coefficient.Complete coefficient 1+A₂/ A₁The whole accumulation of energy abilities that always are present in accumulator are still unexhausted, spring part is not compressed to piece (Block) as yet or pressure piston still abuts under the situation on the backstop.In improvement project of the present invention; Displaceable element has the 3rd pressure side that defines the back pressure chamber at least in part; Wherein, to the pressure medium in back pressure chamber load make displaceable element with the direction opposite to control chamber or reserve chamber on-load pressure medium on move.Therefore improve the pressure that is provided by accumulator once more, this is because the power that now is applied on the displaceable element by accumulator has improved the power that is caused by the pressure to the 3rd pressure side effect.

The pressure support of accumulator can be used in each phase adjustment process.For this purpose, control mechanism (selector valve and/or can remove the blocking-up safety check) always under the situation that requires to adjust mutually, be admitted in the position of emptying reserve chamber.In operation phase between adjustment requires mutually, accumulator can be annotated.Another kind of possibility is that the pressure support of accumulator depends on and need connect.Volume flow not enough or that be used for adjusting mutually is not enough if engine controlling unit detects the pressure that is provided by pressure medium pump, and it is supported through the accumulator release pressure so.This way has prolonged and can also therefore prolong the application of accumulator during pressure is supported to the time that accumulator is annotated.As selection, the pressure support of accumulator can only be used for for example high volume flow of needs or high critical adjustment process of regulating the speed as " supercharging (boost) " function.Need to start this critical adjustment process if engine controlling unit detects, this device switches to the release pressure support through suitable adjustment control mechanism so.

Can consider control mechanism equally and the pressure chamber of pressure medium inflow regulating device and the control valve of controlling from pressure chamber's outflow of regulating device are constituted integratedly.

In embodiment of the present invention, propose, control chamber with the minimum flow area between the fuel tank and reserve chamber with the ratio of the minimum flow area between the adjustment unit greater than the ratio between the area of the area of second pressure side and first pressure side.

What have advantage is, the maximum volume of reserve chamber is equivalent to from the slow position of maximum to adjust volume required twice mutually to position the most very early in the morning at least.Accumulator for example can feed in the pressure medium pipeline between pressure medium pump and the control valve.Can be set to as selecting, accumulator feeds in one of pressure medium pipeline that one of working interface of control valve is connected with one group of pressure chamber.Additional in this embodiment second accumulator that is provided with, this second accumulator feed in other working interfaces of control valve and the pressure medium pipeline that the pressure chamber of other groups is connected.

Description of drawings

Other characteristics of the present invention illustrate the accompanying drawing of the embodiment of the invention from following specification and from simplification.Wherein:

Fig. 1 very schematically illustrates internal-combustion engine,

Fig. 2 a illustrates the longitudinal section of regulating device;

Fig. 2 b illustrates the cross section of regulating device;

Fig. 3 illustrates this device according to first mode of execution of the present invention;

Fig. 4-12 illustrates this device according to other mode of executions of the present invention.

Embodiment

Fig. 1 medium-height grass is drawn internal-combustion engine 1, and wherein, thepiston 3 that is placed on thebent axle 2 illustrates in cylinder 4.Bentaxle 2 is connected through eachtraction mechanism drive 5 andinlet cam axle 6 oroutlet camshaft 7 in the embodiment shown, and wherein, first installs andsecond install 10 and be responsible forbent axle 2 andcamshaft 6, reversing relatively between 7.Thisdevice 10 compriseshydraulic adjustment device 10a, b, c and a pressuremedium supply unit 37 separately.Cam 8 one or more import scavengingair valve 9a of operation ofcamshaft 6,7 or one or more outlet scavenging air valve 9b.Equally only acamshaft 6,7 is equipped withdevice 10 and only is provided with acamshaft 6,7 thatdevice 10 is housed in other words.

Fig. 3 illustrates first mode of execution according todevice 10 of the present invention, and thisdevice 10 has pressuremedium supply unit 37, regulatingdevice 10a, b, c and accumulator 43.Fig. 2 a and 2b illustrate regulatingdevice 10a, b, c with longitudinal section and cross section.Regulatingdevice 10a, b, c have the driving component that constitutes external rotor 22 and constitute the driven member of internal rotor 23.External rotor 22 has housing 22a andside cover 24,25, andside cover 24,25 is arranged on the axial sides of housing 22a.Internal rotor 23 constitutes with the form of impeller and has the hub spare 26 of cylindrical formation basically, in the embodiment shown, and from the shell surface of the external cylindrical of hub spare 26 fiveblades 27 that extend radially outwardly out.Blade 27 is independent of internal rotor 23 ground formation and is arranged in theblade groove 28, andblade groove 28 is configured on the hub spare 26.Blade 27 applies power by theleaf spring 27a radially outward between groove bottom that is arranged onblade groove 28 and theblade 27.

Outer periphery wall 29s from housing 22a extend radially inwardly out a plurality of lug bosses 30.In the embodiment shown,lug boss 30 constitutes with periphery wall 29 integratedly.The periphery wall that external rotor 22 is radially inwardly put bylug boss 30 is rotatably supported on this internal rotor 23 with respect to internal rotor 23.

On the shell surface of periphery wall 29, be provided with bysprocket wheel 21, can be with torque frombent axle 2 to external rotor on 22 bysprocket wheel 21 through unshowned chain drive.

One of each axial sides that is arranged on housing 22a in theside cover 24,25 goes up and is fixed on this side antitorquely.For this purpose, have axially open in eachlug boss 30, this axially open is passed by thefixed block 32 of for example bolt, and fixedblock 32 is used forside cover 24,25 is fixed on housing 22a antitorquely.

Constitutecavity 33 at regulatingdevice 10a, b, c inside between theadjacent lug boss 30 making progress in each two week.33 weeks of each cavity are upwards defined by the opposed wall 34 that defines that distributes diametrically basically ofadjacent protrusion portion 30,side cover 24,25 axially on radially inwardly define and radially outward is defined by periphery wall 29 by hub spare 26.Blade 27 stretches in eachcavity 33, and wherein,blade 27 constitutes as follows, that is,blade 27 had both abutted on theside cover 24,25, also abutted on the periphery wall 29.Therefore eachblade 27 is divided into twopressure chambers 35,36 of effect against each other withcavity 33 separately.

Internal rotor 23 can rotate with respect to external rotor 22 in the angular range of confirming.This angular range defines on a sense of rotation of internal rotor 23 as follows, that is,blade 27 abuts in the defining on the wall 34 (backstop 34a early) of each correspondence of cavity 33.This angular range defines on another sense of rotation as follows similarly, that is,blade 27 abuts in defining on the wall 34 as another of slow backstop 34b ofcavity 33.

Through being pressurizeed in one group ofpressure chamber 35,36 and making another group pressure release, can change the phase place of external rotor 22 with respect to internal rotor 23.Through to 35,36 pressurizations of two groups of pressure chambers, the phase place of two rotors 22,23 is remained unchanged against each other.Can be set topressure chamber 35,36 pressure medium of not annotating during the constant phase place stage as selecting.Usually use the pressure medium of the lubricant oil of internal-combustion engine 1 as hydraulic pressure.

For 35,36 head pressure media are provided with pressure medium supply unit shown in Figure 3 37 to pressure chamber's 35,36 discharge pressure media or from the pressure chamber.Pressuremedium supply unit 37 comprises pressure source,fuel tank 39,control valve 40 and a plurality ofpressure medium pipeline 41 that constitutes pressure medium pump 38.Control valve 40 has input interface P, fuel tank interface T and two working interface A, B.Apressure medium pipeline 41 is connectedpressure medium pump 38 with input interface P separately, and the first working interface A is connected withfirst pressure chamber 35, and the second working interface B is connected withsecond pressure chamber 36 and fuel tank interface T is connected with fuel tank 39.Therefore pressure medium can arrive the input interface P ofcontrol valve 40 frompressure medium pump 38 via pressure medium pipeline 41.On the primary importance ofcontrol valve 40, input interface P is connected withfirst pressure chamber 35, andsecond pressure chamber 36 then is connected with fuel tank 39.On the second place ofcontrol valve 40, be set to,pressure chamber 35,36 is not communicated withfuel tank 39 and input interface P.On the 3rd position ofcontrol valve 40, input interface P is connected withsecond pressure chamber 36, andfirst pressure chamber 35 then is connected withfuel tank 39.

At internal-combustion engine 1 run duration, the conversion moment loading that causes through the rolling ofcam 8 on cam auxiliary equipment (Nockfolger) is incamshaft 6,7.At this, the power of valve spring is opened fully until scavenging air valve and is all acted oncamshaft 6,7 inhibition.Subsequently,camshaft 6,7 quickens through the power of valve spring.The result is, produces pressure peak in the inside of regulatingdevice 10a, b, c, and thepressure chamber 35,36 that this pressure peak causes being connected with input interface P is topressure medium pump 38 emptyings, and this causes regulating the speed obviously slack-off.For preventing this point, be provided withsafety check 42a with inpressure medium pump 38 and thepressure medium pipeline 41 thatcontrol valve 40 is connected.Safety check 42a stopspressure medium 35,36 to reflux topressure medium pump 38 viacontrol valve 40 from the pressure chamber.Therefore pressure peak is supported onsafety check 42a, effectively prevents pressure chamber's 35,36 undesirable emptyings thus and improves the rigidity of transmission of torque and regulate the speed.

The regulating the speed of regulatingdevice 10a, b, c depends on pressure thatpressure medium pump 38 provided or the pressure medium volume flow that is provided.Pressure that is provided or the pressure medium volume flow that is provided depend on a large amount of factors aspect that at it, for example the rotating speed of internal-combustion engine 1 and pressure medium temperature.Even under worst situation, for example when the image height pressure medium temperature and/or the slow-speed of revolution, also guarantee desired regulating the speed,pressure medium pump 38 is respective design therewith.This point causes using that the peak value according to regulatingdevice 10a, b, c requires to design and the thereforepressure medium pump 38 of excessive setting size during most operation phase of internal-combustion engine 1.Also can use adjustablepressure medium pump 38 as selecting,pressure medium pump 38 provides pressure medium as required.Under two kinds of situation, the spending of increase has a negative impact to the cost and the fuel consumption of internal-combustion engine 1.

For avoiding these shortcomings, be provided withaccumulator 43 according todevice 10 of the present invention.Accumulator 43 comprises the displaceable element that constitutespressure piston 45, and pressure piston can move against trying hard to recommend of accumulator in the inside of pressurized container 44.In the embodiment shown, accumulator is embodied as spring part 46.But also can consider the accumulator of other types, for example as the bullet colloid of suitably moulding or the capsule of inflation.

Pressure piston 45 has twopressure sides 47,48.First pressure side 47 andsecond pressure side 48 definereserve chamber 49 andcontrol chamber 50 jointly with pressurized container 44.At this,pressure piston 45 constitutes with pressurizedcontainer 44 as follows,, does not have twochambers 49 being connected between with 50 in the inside ofaccumulator 43 that is.In the embodiment shown, the shift motion ofpressure piston 45 defines throughbackstop 54 for thispurpose.Reserve chamber 49 is connected with pressuremedium supply unit 37 bydeposit pipeline 51, and wherein,deposit pipeline 51 feeds in thissafety check 42a in the downstream of safety check42a.Control chamber 50 can have to be selected to be connected withfuel tank 39 or to be connected with pressure source by pilot line 52.In the embodiment shown, working pressuremedium supply apparatus 37 is as pressure source.But can consider to use other pressure sources equally, for example as thepressure medium pump 38 of the servo customer of servo steering spare.In this case, the pressure medium that flows out fromcontrol chamber 50 is not to import in thefuel tank 39 of internal-combustion engine 1 oil circuit, but thecorresponding fuel tank 39 of the servo customer that leads.

Derive pressure medium flow forsubtend control chamber 50 discharge pressure MEDIA FLOW with fromcontrol chamber 50, be provided with thecontrol mechanism 60 that is first selector valve, 53 forms.First selector valve 53 has pressure interface P₁, control chamber interface A₁With output interface T₁Pressure interface P₁Be connected with pressure source, be connected with pressuremedium supply unit 37 throughpilot line 52 in the embodiment shown.Control chamber interface A₁Be connected and output interface T withcontrol chamber 50₁Be connected with fuel tank 39.On first control position offirst selector valve 53, control chamber interface A₁With pressure interface P₁Connect, and output interface T₁Then not with other interfaces P₁, A₁Be communicated with.On second control position offirst selector valve 53, control chamber interface A₁With output interface T₁Connect, and pressure interface P₁Then not with other interfaces T₁, A₁Be communicated with.

Additionally can be provided with anothersafety check 42b,safety check 42b is arranged in thepilot line 52 and stops pressure medium to reflux to pressuremedium supply unit 37 from control chamber 50.If propose the adjustment requirements todevice 10 at internal-combustion engine 1 run duration engine controlling unit,control valve 40 is in second (centre) position andfirst selector valve 53 is in primary importance so.Therefore pressure medium does not flow or flows out from regulatingdevice 10a to regulating device 10a.Pressure medium both got intoreserve chamber 49 throughdeposit pipeline 51 simultaneously, also got intocontrol chamber 50 through pilot line 52.The pressure medium of introducing inreserve chamber 49 or thecontrol chamber 50 acts onpressure side 47 orpressure side 48, andpressure piston 45 moves towards the trying hard to recommend of direction againstpart 46 ofbackstop 54 thus, thereby the volume ofcontrol chamber 50 andreserve chamber 49 all increases.If the pressure in the pressuremedium supply unit 37 descends, the pressure in thereserve chamber 49 also descends with same degree so.Descend based on the pressure betweencontrol chamber 50 and the pressuremedium supply unit 37, thesafety check 42b in thepilot line 52 closes, and avoids the decline ofcontrol chamber 50 internal pressures thus and has avoided pressure medium fromcontrol chamber 50, to flow out.The result who causes like this is, although the volume ofcontrol chamber 50 andreserve chamber 49 still keeps constant under the situation that pressuremedium supply unit 37 internal pressures in road descend.At this, the stroke x from its position of rest deflection is suitable for for pressure piston 45:

$x=\frac{P_{\max }(A_1+A_2)}{D},$

Wherein, A₁The area that is equivalent tofirst pressure side 47, A₂The area that is equivalent tosecond pressure side 48, p_MaxThe spring constant that maximum system pressure that is equivalent to occur during the filling stage and D are equivalent to spring part 46.At this, the maximum stroke of passing defines through backstop 54.Position of rest is meant the following state ofpressure piston 45, and under this state,spring part 46 is relaxing at utmost.If engine controlling unit requires the phase angular adjustment,control valve 40 is transformed in its primary importance or the 3rd position so.Therefore pressure medium arrivesfirst pressure chamber 35 orsecond pressure chamber 36 frompressure medium pump 38, and adjustment produces through regulatingdevice 10a, b, c mutually thus.If the volume flow bypressure medium pump 38 is carried is adjusted too small or need be reached higher regulating the speed for guaranteeing,first selector valve 53 is transformed in its second control position so.On this second control position,control chamber 50 is connected with fuel tank 39.Therefore the pressure medium that is in thecontrol chamber 50 under the pressure is connectedcontrol chamber 50 emptying rapidly thus with barometricpressure.Reserve chamber 49 is emptied in the pressuremedium supply unit 37 simultaneously.If the pressure medium emptying ofcontrol chamber 50 is so rapid,pressure piston 45 is only supported with respect toreserve chamber 49 throughfirst pressure side 47, whole power ofspring part 46 only act onreserve chamber 49 so.Pressure p when therefore, evacuation procedure being begun in thereserve chamber 49 is suitable for:

$p=\frac{p_{\max }(A_1+A_2)}{A_1},$

As long aspressure piston 45 is not deflection fully as yet, just do not abut on the backstop 54.Because thesafety check 42a in thepressure medium pipeline 41 is arranged in the upper reaches ofdeposit pipeline 51, so guarantee: the total pressure p ofreserve chamber 49 and total volume can supply regulatingdevice 10a to use and not flow out the oil circuit that gets into internal-combustion engine 1.Therefore not only as adopting traditional accumulator, provide current system pressure or maximum filling pressure available, but also provide withcoefficient 1+A₂/ A₁The pressure that improves.Therefore pressuremedium supply unit 37 can obtain the pressure support through second control position that adjusts on first selector valve 53.Therefore, regulating the speed of regulatingdevice 10a constitutes under obvious raising or regulatingdevice 10a under the identical situation of size setting are regulating the speed identical situation littlelyr, and need not adoptpressure medium pump 38 excessive setting size or adjusted.

Can consider following mode of execution equally, that is, and the layout ofcancellation safety check 42b in pilot line 52.In the operation phase that the phase place of internal-combustion engine 1 remains unchanged,accumulator 43 is similar to above-mentioned mode of execution and annotates.If system pressure descends, pressure medium both flowed out fromreserve chamber 49 so, also flowed out from control chamber 50.Cause two chambeies, 49,50 internal pressures to descend like this, therebypressure piston 45 is towards the direction guiding of its position of rest.Therefore, in this mode of execution, no matter be to offer the pressure medium volume of adjustment mutually, or the pressure that can provide in thereserve chamber 49 all descends.However, whenfirst selector valve 53 is transformed into the second switch position, pressure still takes place in thereserve chamber 49 improve.In this case, be suitable for for the pressure p that is provided during deflection fully as yet at pressure piston 45:

$p=\frac{p_{\mathrm{sys}}(A_1+A_2)}{A_1},$

Wherein, p_SysThe system pressure that exists when being equivalent to the pressure support and beginning.Can consider the use of this mode of execution in following internal-combustion engine 1, in this internal-combustion engine 1, at required peak value system pressure only a little more than the ability of pressure medium pump 38.In this case, thesafety check 42b in thepipeline 52 of can removing controls reduces cost thus.

Improve for realizing pressure, to from the pressure medium flow ofcontrol chamber 50 and ratio Q from the pressure medium flow ofreserve chamber 49_D/ Q_VMust be suitable for:

$\frac{Q_D}{Q_V}>\frac{A_2}{A_1}.$

Be set to for reaching this point, for the minimum passage section A betweencontrol chamber 50 and thefuel tank 39_DBe suitable for:

$A_D>\frac{A_2}{A_1}{A}_V,$

Wherein, A_VBe equivalent to the minimum passage section betweenreserve chamber 49 and regulatingdevice 10a or regulatingdevice 10a and thefuel tank 39.

Can consider that equally except thefirst regulating device 10a, one or moreother regulating device 10b, 10c also can control via other pressuremedium pipeline 41 andother control valve 40 through pressure medium supply unit 37.At this,other control systems 10b can have benefited fromaccumulator 43 equally.For this purpose, the branch road that leads to thisregulating device 10b is insafety check 42a back on flow direction.Ifaccumulator 43 should only be supported thefirst regulating device 10a, the branch road that leads toother regulating devices 10c so is arranged onsafety check 42a front on flow direction.

For guaranteeing the functional ofaccumulator 43, be provided with theexhaust part 46a of spring chamber tofuel tank 39.

Can consider that equallysafety check 42a is arranged in the downstream (Fig. 4) of leading to the branch road of laying in pipeline 51.In this case, being supported incontrol gear 10a, b and leading between the branch road of laying inpipeline 51 and carry out pressure peak.Therefore pressure peak can not reachaccumulator 43, reaches the transmission of torque of rigidity more through regulatingdevice 10a, b thus.Can consider that equally the upstream and downstream that in pressuremedium pipeline 41, leads to the branch road of laying inpipeline 51 again uses eachsafety check 42a (Fig. 5).In this case, both reached rigidity transmission of torque, prevented also that the pressure ofreserve chamber 49 or pressure medium volume from flowing out the oil circuit that gets into internal-combustion engine 1 throughcontrol gear 10a, b.

The another kind of mode of execution of thedevice 10 of the present invention of foundation shown in Fig. 6.Be with the difference of mode of execution shown in Figure 3, in this embodiment, indeposit pipeline 51,additional safety check 42c be set.Thissafety check 42c stops pressure medium to flow toreserve chamber 49 from pressuremedium supply unit 37, and the pressure peak that in regulatingdevice 10a, b, c, produces thus is thereserve chamber 49 of advances to accumulator 43 not, but onsafety check 42c, is supported.Therefore the hydraulic pressure category of rigid of thisdevice 10 is similar to the mode of execution raising of Fig. 5.Reserve chamber 49 for fillingaccumulator 43; Be provided with connectingpipeline 55, connectingpipeline 55 feeds between the pressuremedium supply unit 37 andfirst selector valve 53 in thepilot line 52 and on the other hand on the one hand and betweensafety check 42c andreserve chamber 49, feeds in the deposit pipeline 51.At this,additional safety check 42d is set in connectingpipeline 55,safety check 42d stops the pressure medium feed pressuremedium supply apparatus 37 between pressuremedium pump 38 andsafety check 42a from reserve chamber 49.In a kind of variation slightly of this mode of execution, the totalpressure medium pipeline 41 thatsafety check 42b and/orsafety check 42a are arranged at wherein also can be cancelled between the feeding point ofaccumulator 43.

Foundation other mode of executions of the present invention ofdevice 10 shown in Fig. 7 to 11.In these mode of executions, no matter be atpilot line 52, still indeposit pipeline 51, being provided with can be to pressure medium at least towards the through-flow control mechanism of blocking 60 of a direction.

In the mode of execution shown in Fig. 7, be provided with the unique control mechanism that is selector valve 56 forms.This selector valve 56 has pressure interface P₁, control chamber interface A₁, deposit interface V₁, reserve chamber interface B₁With output interface T₁Pressure interface P₁With deposit interface V₁Be connected with pressure source, be connected with pressure medium supply unit 37 through pilot line 52 or deposit pipeline 51 in the embodiment shown.Control chamber interface A₁Be connected reserve chamber interface B with control chamber 50₁Be connected and output interface T with reserve chamber 49₁Be connected with fuel tank 39.In addition, be provided with connecting pipeline 55, connecting pipeline 55 feeds between selector valve 56 and control chamber 50 in the pilot line 52 and on the other hand on the one hand and between selector valve 56 and reserve chamber 49, feeds in the deposit pipeline 51.In connecting pipeline 55, be provided with safety check 42d, safety check 42d stops pressure medium to flow to pilot line 52 from deposit pipeline 51.On first control position of selector valve 56, control chamber interface A only₁With pressure interface P₁Connect, and other total interfaces B₁, T₁, V₁Then sealing.On second control position of selector valve 56, deposit interface V₁With reserve chamber interface B₁Be communicated with and control chamber interface A₁With fuel tank interface T₁Be communicated with, and pressure interface P₁Then not with other interfaces A₁, B₁, T₁, V₁Be communicated with.

If internal-combustion engine 1 run duration, engine controlling unit do not propose the adjustment requirement todevice 10, selector valve 56 is in first control position so.In this state, pressure medium can get intocontrol chamber 50 viapilot line 52 and selector valve 56 from pressure medium supply unit 37.Simultaneously,reserve chamber 49 is annotated through connectingpipeline 55 equally.In this state,accumulator 43 is similar to theaccumulator 43 shown in Fig. 3.Trying hard to recommend ofpressure piston 45 againstparts 46 moves andchamber 49,50 filling pressure mediums.If the pressure of pressuremedium supply unit 37 descends, the pressure in thecontrol chamber 50 descends equally so.Butreserve chamber 49 keeps high pressure conditions, and this is becausereserve chamber 49 is passed through selector valve 56 and isolated with respect to pressuremedium supply unit 37 throughsafety check 42d on the other hand on the one hand.Thereforeaccumulator 43 keeps its state of having annotated.If selector valve 56 is transformed into second state of a control, so on the onehand control chamber 50 be emptied in thefuel tank 39 and on the otherhand reserve chamber 49 be emptied in the pressure medium supply unit 37.This process and first mode of execution carry out (Fig. 3) similarly.

Fig. 8 illustrates according to another embodiment of the invention, and the difference of this mode of execution and front mode of execution only is the layout of safety check 42a.At this, the mode of execution ground thatsafety check 42a is similar to Fig. 4 is provided with.Also can consider to be similar to the mode of execution with twosafety check 42a of Fig. 5, two one ofsafety check 42a are arranged on the upper reaches and downstream atdeposit pipeline 51 ofdeposit pipeline 51.

Fig. 9 to 11 illustrates basically and installs 10 with of the present invention other of foundation identical shown in Fig. 7 and 8.Be that with the difference of the mode of execution shown in Fig. 7 and 8device 10 shown in Fig. 9 to 11 replaces unique control mechanism 60 (being provided with unique selector valve 56 in the embodiment shown) and is provided with two control mechanisms 60.At this, being communicated with between first control mechanism, 60 pilot pressuremedium supply apparatus 37 and thereserve chamber 49,second control mechanism 60 is being communicated with between pilot pressuremedium supply apparatus 37,control chamber 50 and thefuel tank 39 then.

In the mode of execution shown in Fig. 9;First control mechanism 60 constitutes thesafety check 42e that can remove blocking-up;Safety check 42e authorized pressure medium on first control position flows to reservechamber 49 from pressuremedium supply unit 37, but forbids opposite pressure medium flow.On second control position, equal authorized pressure media flow on both direction.Second control mechanism 60 isfirst selector valve 53 shown in first mode of execution in this case.

Be that with the difference of Fig. 9 mode of execution Figure 10 illustrates following mode of execution, wherein, thesafety check 42e that can remove blocking-up is replaced by second selector valve 57 (being the 2/2-way selector valve in this particular embodiment).On first control position,second selector valve 57 not authorized pressure medium flows between pressuremedium supply unit 37 and reserve chamber 49.On second control position, pressure medium all can flow on both direction.

Be with the difference of Figure 10 mode of execution; Figure 11 illustrates following mode of execution, and wherein,first selector valve 53 is made following change; Promptly on first control position; Only 50 direction flows the authorized pressure medium from pressuremedium supply unit 37 towards control chamber, and on the contrary, infirst selector valve 53, forbids reverse pressure medium flow.

Fig. 12 illustrates another kind of scheme of the present invention, and this scheme is introduced by the mode of execution shown in Fig. 6.What need spell out is all can use in this scheme all mode of executions in front.This device 10 is that with the difference of device 10 shown in Figure 6 connecting pipeline 55 feeds in the pilot line 52 and the exhaust part 46a of spring chamber is not set between first selector valve 53 and control chamber 50.And spring chamber be configured to can by the filling pressure medium back pressure chamber 58.First selector valve 53 is provided with additional back pressure interface G in this embodiment, and back pressure interface G is communicated with back pressure chamber 58.On first control position of first selector valve 53, control chamber interface A₁With pressure interface P₁Connect, back pressure interface G then with output interface T₁Be communicated with.On second control position of first selector valve 53, control chamber interface A₁With output interface T₁Connect, and pressure interface P₁Then be communicated with back pressure interface G.If first selector valve 53 is on first control position, do not occur changing with respect to Fig. 6 mode of execution so.But on second control position, additionally pressure medium is imported in the back pressure chamber 58.This pressure medium applies power to the 3rd pressure side 59 of pressure piston 45, and this power acts on the direction identical with spring part 46.The additional thus pressure that improves in the reserve chamber 49.

Shown in whole mode of executions in,accumulator 43 with pressuremedium pump 38 is communicated with thepressure medium pipeline 41 that one ormore control valves 40 are connected.Same admissible mode of execution is, one ormore accumulators 43 feed in one ormore control valves 40 and thepressure medium pipeline 41 that regulatingdevice 10a, b are connected.

Be used for internal-combustion engine 1 port timing is carried out the application of variable adjustment exceptaccumulator 43 is used in,accumulator 43 also can be used in other automotive applications, for example is used in the convertible cam auxiliary equipment perhaps to be used in the application of automatic transmission.

Reference numerals list

1 internal-combustion engine

2 bent axles

3 pistons

4 cylinders

5 traction mechanism drives

6 inlet cam axles

7 outlet camshafts

8 cams

9a import scavenging air valve

9b exports scavenging air valve

10 devices

10a first regulating device

10b, other regulating devices of c

21 sprocket wheels

22 external rotors

The 22a housing

23 internal rotors

24 side covers

25 side covers

26 hub spares

27 blades

The 27a leaf spring

28 blade grooves

29 periphery walls

30 lug bosses

32 fixed blocks

33 cavitys

34 define wall

34a is backstop early

The slow backstop of 34b

35 first pressure chambers

36 second pressure chambers

37 pressure medium supply units

38 pressure medium pump

39 fuel tanks

40 control valves

41 pressure medium pipelines

The 42a safety check

The 42b safety check

The 42c safety check

The 42d safety check

42e can remove the safety check of blocking-up

43 accumulators

44 pressurized containers

45 pressure pistons

46 spring parts

The 46a exhaust part

47 first pressure sides

48 second pressure sides

49 reserve chamber

50 control chambers

51 deposit pipelines

52 pilot line

53 first selector valves

54 backstops

55 connecting pipelines

56 selector valves

57 second selector valves

58 back pressure chambeies

59 the 3rd pressure sides

60 control mechanisms

A first working interface

B second working interface

The P input interface

The T output interface

P₁Pressure interface

T₁Output interface

A₁The control chamber interface

B₁The reserve chamber interface

V₁The deposit interface

G back pressure interface

Claims (18)

1. be used for the device (10) that the port timing of the scavenging air valve (9a, b) to internal-combustion engine (1) is carried out variable adjustment, said device (10) has

Driving component (22), driven member (23), at least one pressure chamber (35,36), pressure medium supply unit (37) and at least one accumulator (43),

Wherein, by said pressure medium supply unit (37) can to said at least one pressure chamber (35,36) discharge pressure medium or from said at least one pressure chamber (35,36) the head pressure medium,

Wherein, through to said pressure chamber (35,36) discharge pressure medium or from said pressure chamber (35,36) the head pressure medium, can change the phase place of said driven member (23) with respect to said driving component (22),

Wherein, said accumulator (43) has displaceable element (45), and said displaceable element (45) has first pressure side (47), and said first pressure side (47) partly defines reserve chamber (49),

Wherein, said reserve chamber (49) is connected with said pressure medium supply unit (37),

Wherein, said displaceable element (45) is moved against trying hard to recommend of accumulator (46), it is characterized in that through pressurization to said reserve chamber (49),

Said displaceable element (45) has at least one second pressure side (48), and said second pressure side (48) partly defines control chamber (50),

Wherein, said displaceable element (45) is moved against trying hard to recommend of said accumulator (46) through pressurization to said control chamber (50), and

Wherein, in the inside of said accumulator (43) not the authorized pressure medium flow into said control chamber (50) from said reserve chamber (49).

2. by the described device of claim 1 (10), it is characterized in that said control chamber (50) can be connected with pressure source (38) or fuel tank (39) at said internal-combustion engine (1) run duration selectively.

3. by the described device of claim 1 (10), it is characterized in that said control chamber (50) can not detour via customer and just be emptied in the fuel tank (39).

4. by the described device of claim 2 (10), it is characterized in that, be provided with control mechanism (60), wherein, said control chamber (50) can be connected with fuel tank (39) or said pressure source (38) by said control mechanism (60) selectively.

5. by the described device of claim 2 (10), it is characterized in that, be provided with control mechanism (60),

Said control mechanism (60) is blocked under first state from said reserve chamber (49) and is also allowed the pressure medium flow to said reserve chamber (49) and said control chamber (50) to the pressure medium flow of said pressure medium supply unit (37), and

Said control mechanism (60) is allowing not set up being connected between said control chamber (50) and the fuel tank (39) from said reserve chamber (49) via customer to the pressure medium flow of said pressure medium supply unit (37) with detouring under the other state.

6. by the described device of claim 5 (10); It is characterized in that; Be provided with deposit pipeline (51); Said deposit pipeline (51) is connected said pressure medium supply unit (37) with said reserve chamber (49), and is provided with pilot line (52), and said pilot line (52) is connected said control chamber (50) with pressure source (38).

7. by the described device of claim 6 (10); It is characterized in that; Said control mechanism (60) constitutes unique selector valve (56), and said selector valve (56) has each the interface (A that is used for said deposit pipeline (51), said pilot line (52), said control chamber (50), said reserve chamber (49) and said fuel tank (39)₁, B₁, P₁, T₁, V₁).

8. by the described device of claim 6 (10), it is characterized in that said control mechanism (60) comprises that at least one is arranged on first selector valve (53) in the said pilot line (52).

9. by the described device of claim 8 (10); It is characterized in that; Said control mechanism (60) also comprises second selector valve (57) or can remove the safety check (42e) of blocking-up that the safety check (42e) that said second selector valve (57) perhaps can be removed blocking-up is arranged in the said deposit pipeline (51).

10. by the described device of claim 8 (10), it is characterized in that, said control mechanism (60) also comprise be arranged in the said deposit pipeline (51), can remove the safety check of blocking (42e).

11. by the described device of claim 5 (10); It is characterized in that; Said reserve chamber (49) is connected through safety check (42d) with said control chamber (50), and wherein, this connection is arranged between said control mechanism (60) and said chamber (49,50); And wherein, said safety check (42d) blocking-up is from the pressure medium flow of said reserve chamber (49) to said control chamber (50).

12. by the described device of claim 1 (10); It is characterized in that; Between said control chamber (50) and said pressure source (38), be provided with safety check (42b), said safety check (42b) is blocked from the pressure medium flow of said control chamber (50) to said pressure source (38) direction.

13. by the described device of claim 1 (10); It is characterized in that; Between said reserve chamber (49) and said pressure medium supply unit (37), be provided with safety check (42c), said safety check (42c) is blocked from the pressure medium flow of said pressure medium supply unit (37) to said reserve chamber (49) direction.

14. by the described device of claim 1 (10), it is characterized in that, with the same, said displaceable element (45) moved on identical direction to said control chamber (50) on-load pressure medium to said reserve chamber (49) on-load pressure medium.

15. by the described device of claim 1 (10); It is characterized in that; Said displaceable element (45) has the 3rd pressure side (59), and said the 3rd pressure side (59) defines back pressure chamber (58) at least in part, wherein; With different, said displaceable element (45) is moved said back pressure chamber (58) on-load pressure medium in the opposite direction to said control chamber (50) or said reserve chamber (49) on-load pressure medium.

16. by one of claim 2 or 5 described device (10); It is characterized in that, in the ratio of minimum flow area between said control chamber (50) and the said fuel tank (39) and the minimum flow area between said reserve chamber (49) and said regulation unit (10a, b) ratio greater than the area of the area of said second pressure side (48) and said first pressure side (47).

17., it is characterized in that said reserve chamber (49) is not interconnected in the inside of said accumulator (43) with said control chamber (50) by the described device of claim 1 (10).

18., it is characterized in that said control mechanism (60) constitutes selector valve (53) by the described device of claim 4 (10).

Images