A kind of planetary roller screw transmission systemTechnical field
The present invention relates to driving parts technical field, specially a kind of planetary roller screw transmission system.
Background technique
Planetary roller screw is exactly to be evenly arranged 6-12 threaded rollers planetaryly around lead screw, thisThe rotary motion of motor can be converted to the linear motion of lead screw or nut by sample.Planetary roller screw can be extremely arduousIt works under environment, and heavy duty thousands of hours can be born, our present application conditions are gradually towards high-mechanic, high lifeDirection is developed, and planetary roller screw just becomes the ideal selection for the application for requiring continuous work.
Current planetary roller screw cannot according to load and planetary roller screw parameter calculate motor revolving speed andThere is low load with strong power to cause can not to select the parameter of suitable motor and retarder in power " or " high load with small power "The case where, both of these case can all reduce working efficiency.In consideration of it, we provide a kind of planetary roller screw transmission system.
Summary of the invention
The purpose of the present invention is to provide a kind of planetary roller screw transmission systems, to solve to propose in above-mentioned background techniqueNowadays there is low load with strong power in planetary roller screw " or the case where " high load with small power ", the problem of reducing working efficiency.
To achieve the above object, the invention provides the following technical scheme:
A kind of planetary roller screw transmission system, including motor, the retarder being connected with the motor and planetary rollerMechanism, the planetary roller mechanism are made of three lead screw, roller, nut components, and the lead screw is connected with the retarder, instituteIt states lead screw and drives planetary roller mechanism axially movable, load, the planetary roller machine are provided in the planetary roller mechanismStructure band dynamic load moves in a straight line；
The working principle of the planetary roller mechanism is consistent with the working principle of planetary gear train, and the lead screw is the sunWheel, the roller are planetary gear, and the nut is external fixation gear, if installing dry milling in the outer circumferential walls of the lead screwColumn is provided with ring gear and retaining ring, the roller and ring gear gear engagement in each roller, described in the retaining ring guaranteesRoller is uniformly distributed on lead screw circumferencial direction.
Preferably, the movement between the lead screw, the roller and the nut in a circumferential direction is pure rolling, instituteIt is identical as the helix angle of the nut to state roller, guarantees during engagement relatively pure between the roller and the nutIt rolls and without displacement to axial.
Preferably, the lead screw often rotates a circle, the roller is fixed relative to the axial displacement of the lead screwValue, the value of the fixation are the lead of planetary roller screw.
Preferably, the lead screw uses multiple thread, the roller uses one start screw, the roller and the lead screwTooth form it is identical, in order to improve the bearing capacity of mechanism, by the screw thread process of the roller at arc surface, arc surface reduction rubsIt wipes, improves transmission efficiency.
Preferably, the lead screw, the roller are identical with the thread rotary orientation of the nut, the lead screw and the nutIt is all made of multiple thread, and number of starts is identical.
Preferably, the lead screw, the roller are identical with the nut thread screw pitch, the quantity increase of the roller is heldThe quantity of loading capability, the roller is limited in space.
Preferably, the ring gear and roller gear engagement, and it is equal to take turns tooth module.
Preferably, the motor uses different revolving speeds, in the case where guide screw lead is constant, the retarder subtractsSpeed ratio can change accordingly, if the revolving speed of the motor increases, the reduction ratio of the retarder just be will increase, then the motor needsTorque to be offered can reduce, and the power of the motor will not change.
Preferably, the revolving speed of the motor is constant, change the lead of the lead screw, increases the guide screw lead, it is describedThe revolving speed of lead screw reduces, and the reduction ratio of the retarder increases, and the torque that the motor provides reduces, and the power of motor is constant.
Preferably, the calculating of the motor inertia is related with the size of part and working condition, in system operationIn the process, the lead screw is rotary motion, and the roller revolves around lead screw axis also can be around itself axis rotation, and in axial directionThe working condition of upper also mobile working condition, the nut and the load is linear motion.
Compared with prior art, the beneficial effects of the present invention are:
1, this planetary roller screw transmission system lead screw is rotated in circumferencial direction, and roller around lead screw during revolvingMeeting rotation, nut band dynamic load are moved in a straight line along axial direction, and roller and the engagement of ring gear gear, retaining ring guarantee the phase of roller positionTo fixation.In parameter calculation procedure, lead screw size is selected according to load, selects the parameter of roller and nut accordingly, andThe parameter of ring gear and retaining ring.The revolving speed and power of motor are calculated according to load and planetary roller screw parameter, selection is closedThe parameter of suitable motor and retarder, the case where avoiding the occurrence of " low load with strong power " and " high load with small power ".
2, in this planetary roller screw transmission system lead screw roller and lead screw contact radius it is bigger and all roller it is sameWhen participate in engagement, it is more relative to ball-screw contact point.This means that in the identical situation of lead screw diameter, roller screwBearing capacity it is higher.It is loading under the same conditions, the volume of roller screw can be done smaller.Roller screw uses the longevityLife increases substantially, operating ambient temperature range is also improved；Roller screw replaces sliding friction with rolling friction, with ball wireThick stick transmission efficiency is suitable, lubricates in good situation efficiency up to 90%；Roller is not axially moved relative to nut, therefore is hadThere is the ability of acceleration, rotation and deceleration, revolving speed is reachable, space rate, acceleration, and ball-screw is extremely difficult to These parameters；Planetary roller screw does not need installation circulator, therefore the vibration noise generated when running at high speed is smaller；It can be in severe ringIt is used under border.Roller screw both ends process straight-tooth again, engage with the ring gear being mounted in nut, it is ensured that work well；Roller screw is convenient for disassembly and assembly, and when disassembly can directly screw out nut, does not need to remove roller.
Detailed description of the invention
Fig. 1 is planet roller screw mechanism figure provided by the invention；
Fig. 2 is planetary roller screw inner detail diagram provided by the invention；
Fig. 3 is planetary roller screw gear mesh schematic representation provided by the invention.
In figure: 1, motor；2, retarder；3, lead screw；4, planetary roller mechanism；5, it loads；6, roller；7, nut；8, interiorGear ring；9, retaining ring.
Specific embodiment
Below in conjunction with the embodiment of the present invention, technical scheme in the embodiment of the invention is clearly and completely described,Obviously, described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.Based in the present inventionEmbodiment, every other embodiment obtained by those of ordinary skill in the art without making creative efforts, allBelong to the scope of protection of the invention.
In the description of the present invention, it is to be understood that, term " center ", " longitudinal direction ", " transverse direction ", " length ", " width "," thickness ", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outside", " up timeThe orientation or positional relationship of the instructions such as needle ", " counterclockwise " is to be based on the orientation or positional relationship shown in the drawings, and is merely for convenience ofThe description present invention and simplified description, rather than the equipment of indication or suggestion meaning or element must have a particular orientation, with spyFixed orientation construction and operation, therefore be not considered as limiting the invention.
Embodiment 1
A kind of planetary roller screw transmission system, as shown in Figure 1, include motor 1, the retarder 2 that is connected with motor 1 andPlanetary roller mechanism 4, planetary roller mechanism 4 are made of 7 three lead screw 3, roller 6, nut components, lead screw 3 and 2 phase of retarderEven, lead screw 3 drives planetary roller mechanism 4 axially movable, and load 5, planetary roller mechanism 4 are provided in planetary roller mechanism 4Band dynamic load 5 moves in a straight line；
It is worth noting that the working principle of planetary roller mechanism 4 is consistent with the working principle of planetary gear train, do not considerAxial displacement rotates for several planetary gears around sun gear, and when sun gear rotation, planetary gear i.e. meeting rotation also can be around sun gear public affairsTurn, here it is planetary roller screws to run basic principle, and lead screw 3 is sun gear, and roller 6 is planetary gear, and nut 7 is external consolidatesFixed gear installs several rollers 6 in the outer circumferential walls of lead screw 3, ring gear 8 and retaining ring 9,6 He of roller is provided in each roller 6The engagement of 8 gear of ring gear, retaining ring 9 guarantee that roller 6 is uniformly distributed on 3 circumferencial direction of lead screw.
Since planetary roller screw is precision drive component, can be generated when roller screw radial direction is by load largerDeformation, therefore so that roller screw is solely subjected to axial load in actual work, thus working condition only consider it is verticalWorking condition, even if working condition is not stringent vertical state sometimes, this is just needed through external design machineStructure eliminates lateral load.
Further, the movement between lead screw 3, roller 6 and nut 7 in a circumferential direction is pure rolling, roller 6 and nut7 helix angle is identical, guarantees relatively pure rolling and the position of nothing to axial between roller 6 and nut 7 during engagementIt moves, lead screw 3 often rotates a circle, and roller 6 is fixed value relative to the axial displacement of lead screw 3, and fixed value is planetary roller silkThe lead of thick stick.
Lead screw is rotated in circumferencial direction in the planetary roller screw transmission system of the present embodiment, and roller 6 revolves around lead screw 3During also can rotation, nut 7 moves in a straight line with dynamic load along axial direction, and roller 6 and the engagement of 8 gear of ring gear, retaining ring 9 are protectedDemonstrate,prove the relatively fixed of roller position.In parameter calculation procedure, 3 size of lead screw is selected according to load 5, it is corresponding select roller andThe parameter and ring gear of nut and the parameter of retaining ring.Turning for motor 1 is calculated according to load 5 and planetary roller screw parameterSpeed and power, select the parameter of suitable motor 1 and retarder, avoid the occurrence of " low load with strong power " and " high load with small power "The case where.
Embodiment 2
As second of preferred embodiment of the invention, lead screw 3 uses multiple thread, and roller 6 uses one start screw, roller6 is identical as the tooth form of lead screw 3, in order to improve the bearing capacity of mechanism, by the screw thread process of roller 6 at arc surface, arc surface dropLow friction improves transmission efficiency.
Further, lead screw 3, roller 6 are identical with the thread rotary orientation of nut 7, and lead screw 3 and nut 7 are all made of multiple thread,And number of starts is identical, lead screw 3, roller 6 are identical with 7 thread pitch of nut, and the quantity of roller 6 increases bearing capacity, roller 6Quantity is limited in space.
It is worth noting that ring gear 8 and the engagement of 6 gear of roller, and it is equal to take turns tooth module.
Specifically, as shown in figure 3, wherein drFor 6 diameter of roller, dnIt is nut 7 in diameter, the d with 6 contact position of rollersForThe diameter of lead screw 3 and 6 contact position of roller；dmIt is the revolution diameter of roller 6；ωrIt is 6 spin velocity of roller；ωmIt is that roller 6 revolvesAngular speed；ωsIt is the angular speed of lead screw 3, following relationship can be obtained:
Obtain the revolution angular speed of roller 6 are as follows:
Wherein
Have again:
Obtain 6 spin velocity of roller are as follows:
After lead screw 3 circles, axial displacement H of the roller 6 relative to nut 71Are as follows:
WhereinIndicate movement of the nut 7 relative to lead screw 3, nnFor nut head number, s is screw pitch,Indicate roller6 moving distance relative to lead screw 3, nut 7 is identical as 6 rotation direction of roller, takes minus sign, obtains:
By known conditions, nut 7 is axial without relative motion relative to roller 6, so H1=0, it obtains:
Lead screw 3 rotates a circle, moving distance of the roller 6 relative to lead screw 3 are as follows:
Wherein according to circumstances judge that symbol all takes top, indicates that rotation direction is identical, nsFor 3 numbers of lead screw, by ωrAnd ωmBandEnter to obtain:Ideal H2It should be constant, can guarantee the stationarity of movement in this way.At this moment have:So ns=nn=k+2, H2=nsS is constant.
The engagement process of planetary gear train as shown in Figure 3 is exactly that ring gear 8 is engaged with the gear at 6 both ends of roller, m1It is interior8 module of gear ring, m2For 6 module of roller, ZnFor 8 number of teeth of ring gear, ZrFor 6 number of teeth of roller, by formula (6), wherein dn=m1Zn, dr=m2Zr, gear engagement, so m1=m2, so Zn=(k+2) Zr。
Embodiment 3
As the third preferred embodiment of the invention, motor 1 uses different revolving speeds, in the situation that guide screw lead is constantUnder, the reduction ratio of retarder 2 can change accordingly, if the revolving speed of motor 1 increases, the reduction ratio of retarder 2 just be will increase, then electricMachine 1 needs torque to be offered that can reduce, and the power of motor 1 will not change.
Further, the revolving speed of motor 1 is constant, changes the lead of lead screw 3, increases 3 lead of lead screw, and the revolving speed of lead screw 3 subtractsSmall, the reduction ratio of retarder 2 increases, and the torque that motor 1 provides reduces, and the power of motor 1 is constant.
Specifically, the calculating of 1 inertia of motor is related with the size of part and working condition, in the process of system operationIn, lead screw 3 is rotary motion, roller 6 around lead screw axis revolve also can around itself axis rotation, and in the axial direction there are also mobileWorking condition, nut 7 and load 5 working condition be linear motion.
The motor 1 of the present embodiment can choose different motor speeds, meet the requirement of power and torque, also meetThe requirement of inertia, during system operation, lead screw 3 is rotary motion, and roller 6 also can be around itself around the revolution of 3 axis of lead screwAxis rotation, and there are also mobile working conditions in the axial direction.And nut 7 and the working condition of load 5 are exactly straight line fortuneIt is dynamic, rotary motion can't be generated.
1 torque arithmetic of planetary roller screw driving motor is complicated, does approximate calculation, this approximation using ball-screw hereCalculating can apply the situation not high in accuracy requirement, calculation formula are as follows:
Ta indicates driving torque, units/kg f.mm in formula；Fa indicates axial load, unit N；P is guide screw lead；η1It indicatesThe transmission efficiency of roller screw.
Under vertical working condition, axial load calculation formula are as follows:
Fa=F+ μm of g (9)
F is axial cutting force, unit N in formula；μ is the SimMan universal patient simulator of guide part；The weight of m expression workbench.
The inertia of lead screw 3 are as follows:
The inertia of roller 6 are as follows:
The inertia of nut 7 is (nut does not rotate identical with load calculating method):
So roller screw inertia are as follows:
Wherein n is roller quantity.
Load 5 equivalent inertias are as follows:
Select the rotary inertia of motor 1 are as follows:
When actual selection motor 1 and retarder 2, usual motor 1 and 5 rotary inertia 1:10 of load are that can expireIt requires enough, it is possible to a variety of motors be selected further to compare according to the actual situation.
Lead screw is rotated in circumferencial direction in planetary roller screw transmission system of the invention, and roller 6 is revolving around lead screw 3In the process also can rotation, nut 7 moves in a straight line with dynamic load along axial direction, and roller 6 and the engagement of 8 gear of ring gear, retaining ring 9 guaranteeRoller position it is relatively fixed.In parameter calculation procedure, 3 size of lead screw is selected according to load 5, it is corresponding to select roller and spiral shellThe parameter of female parameter and ring gear and retaining ring.The revolving speed of motor 1 is calculated according to load 5 and planetary roller screw parameterAnd power, the parameter of suitable motor 1 and retarder is selected, " low load with strong power " and " high load with small power " is avoided the occurrence ofSituation.
The basic principles, main features and advantages of the present invention have been shown and described above.The technology of the industryFor personnel it should be appreciated that the present invention is not limited to the above embodiments, described in the above embodiment and specification is only the present inventionPreference, be not intended to limit the invention, without departing from the spirit and scope of the present invention, the present invention also has variousChanges and improvements, these changes and improvements all fall within the protetion scope of the claimed invention.The claimed scope of the invention is by instituteAttached claims and its equivalent thereof.