EP0070617B1

Movatterモバイル変換

Info

Publication number: EP0070617B1
Application number: EP19820302818
Authority: EP
Inventors: Masaharu Hiraga; Kazuo Sugimoto; Tadashi Sato
Original assignee: Sanden Corp
Current assignee: Sanden Corp
Priority date: 1981-05-30
Filing date: 1982-06-01
Publication date: 1985-04-10
Also published as: EP0070617A3; EP0070617A2; AU8434582A; DE3262964D1; JPS57198386A; AU552132B2

Description

This invention relates to a fluid displacement apparatus, and more particularly, to a scroll type fluid displacement apparatus for use as a supercharger for an engine or as an air pump.
Scroll type fluid displacement apparatus are well known in the prior art. For example, U.S. Patent No. 801,182 (Creux) discloses a device including two scrolls each having a circular end plate and a spiroidal or involute spiral element. These scrolls are maintained angularly and radially offset so that both spiral elements interfit to make a plurality of line contacts between their spiral curved surfaces to thereby seal off and define at least one pair of fluid pockets. The relative orbital motion of the scrolls shifts the line contacts along the spiral curved surfaces and, as a result, the volume of the fluid pockets changes. Since, the volume of the fluid pockets increases or decreases dependent on the direction of the orbital motion, the scroll type fluid displacement apparatus is applicable to compress, expand or pump fluids.
Scroll type fluid displacement apparatus have been used as a refrigerant compressor in refrigerator or air conditioning apparatus. Such compressors need high efficiency and a high compression ratio, such as 5 to 10 compression ratio. In such a compressor, the re-expansion volume, i.e., the smallest volume of the fluid pockets in a compression cycle, which is located at the center of the scroll members in a scroll type compressor, must be reduced as much as possible. To this end, the inner end portion of the spiral elements are extended inwardly as far as possible to the center of the scroll member.
However, when a scroll type fluid displacement apparatus is used for a supercharger or an air pump which requires a compression ratio of only 1.0 to 1.5, the re-expansion volume needs not be reduced as much as in the high compression ratio application. In an apparatus which requires only a low compression ratio, pressure difference between the high pressure space and the lower pressure space is smaller than in a high compression ratio application, so that 1.5 to 2.0 revolutions of spiral element generally is sufficient. Particularly, the apparatus which is used as the supercharger for engine is carried on the engine and effects the power up of the engine by supercharging air to the engine. The engine with the supercharger is controlled by external environment, for example, in starting or high power driving situation, the engine needs the supercharged air to power up the engine, while, in the constant drive situation, the engine requiring not so much supercharged air. The supercharger must be provided with the control means for the operation of the apparatus.
It is a primary object of the invention to provide an improvement in a scroll type fluid displacement apparatus having a control means for controlling the operation of the apparatus by change of external environment.
It is another object of this invention to provide a scroll type fluid displacement apparatus which is simple to construct and can be simply and reliably manufactured.
According to the present invention there is provided a scroll type fluid displacement apparatus including a housing having an inlet port and an outlet port, a fixed scroll joined with said housing and having a first end plate from which a first wrap extends into an operative interior area of said housing, an orbiting scroll having a second end plate from which a second wrap extends, said first and second wraps interfitting at an angular and radial offset to make a plurality of line contacts to define at least one pair of fluid pockets within said operative interior area, a driving mechanism (15-151-152) connected to said orbiting scroll to drive said orbiting scroll in an orbital motion, and a rotation preventing means for preventing the rotation of said orbiting scroll so that the volume of fluid pockets changes during the orbital motion of said orbiting scroll, characterized by an opening portion formed on said first end plate for connecting with a lower pressure space of the operative interior and a center space of said wraps, and a control means for controlling the opening and closing of said opening portion to control the operation of said apparatus.
The invention will now be described, by way of example, with reference to the accompanying drawings, in which:-

Fig. 1 is a vertical sectional view of a scroll type fluid displacement apparatus according to an embodiment of this invention;
Figs. 2a-2d are sectional views taken along line II-II in Fig. 1 illustrating the operation of the apparatus;
Fig. 3 is a sectional view taken along the line II-II in Fig. 1 according to another embodiment of this invention; and
Fig. 4 is a partially sectional view of a scroll type fluid displacement apparatus according to another embodiment of this invention.

Referring to Fig. 1, an embodiment of a fluid displacement apparatus in accordance with the present invention, in particular, a scroll type apparatus 1 is shown. Apparatus 1 includes ahousing 10 having afront end plate 11 and a cup shapedcasing 12, which is attached to one end surface offront end plate 22 by a plurality of bolts 13. An opening in cup shapedcasing 12 is covered byfront end plate 11 to seal offinner chamber 14 of cup shapedcasing 12. Anopening 111 is formed in the center offront end plate 11 for penetration or passage of adrive shaft 15.Front end plate 11 has anannular sleeve 16 projecting from the front end surface thereof which surroundsdrive shaft 15. In the embodiment shown in Fig. 1,sleeve 16 is separated fromfront end plate 11. Therefore,sleeve 16 is fixed to the front end surface orfront end plate 11 by bolts 13 with cup shapedcasing 12.
Apulley 17 is rotatably supported by abearing 18 which is carried on the outer surface ofsleeve 16. The outer end portion ofdrive shaft 15, which extends fromsleeve 16, is fixed onpulley 17 by a key 19 and bolt 20 throughshims 21.Drive shaft 15 is thus driven by an external drive power source throughpulley 17.
A fixedspiral element 122 is formed integral withend plate portion 121 of cup shapedcasing 12 and extends intoinner chamber 14 of cupshaped casing 12.Spiral element 122, which has approximately 1 and 3/4 turns or revolutions, has a trapezoidal shaped as shown in Fig. 1. Anoutlet port 123 is formed through theend plate portion 121 of cup shapedcasing 12 and aninlet port 124 is formed through the outer peripheral surface of cup shapedcasing 12.
An orbitingscroll 22 is also located withininner chamber 14 of cup shapedcasing 12 and includes acircular end plate 221 and orbital wrap orspiral element 222 affixed to or extending from one side surface ofend plate 221. Atubular member 223 projects axially from a generally center area of the side surface ofend plate 221. Fixedspiral element 122 and orbitingspiral element 222 interfit at an angular offset of 180° and a predetermined radial offset. At least a pair of fluid pockets are defined betweenspiral elements 122 and 222.Tubular member 223 has ahollow interior 224 extending through its center.
Drive shaft 15 has a disk shapedrotor 151 at its inner end which is rotatably supported byfront end plate 11 through abearing 23 located within opening 111 offront end plate 11. Acrank pin 152 projects axially from an axial end surface ofrotor 151 at a position which is radially offset from the center ofdrive shaft 15.Crank pin 152 is carried inhollow interior 224 oftubular member 223 by abearing 24.Bearing 24 is held within a ledge inhollow interior 224 by asnap ring 25 and aprojection 225 formed on the inner surface ofhollow interior 224.Snap ring 25 is attached on the inner end ofcrank pin 152 and aspring washer 26 is placed betweensnap ring 25 and bearing 24. Accordingly, orbitingscroll 22 is pushed againstfront end plate 11 byspring washer 26.
A rotation preventing/thrust bearingdevice 28 is located between the inner end surface offront end plate 11 and an axial end surface ofend plate 221 of orbitingscroll 22. Rotation preventing/ thrust bearingdevice 28 includes a plurality offixed indentations 281 formed on the inner end surface offront end plate 11, a plurality of orbitingindentations 282 formed on the axial end surface ofend plate 221 and, a plurality of bearingelements 283, such as balls. Eachball 283 is placed in facing, generally alignedindentations 281 and 282. The rotation of orbitingscroll 22 is prevented by the interaction betweenballs 283 andindentations 281 and 282; also the axial thrust load from orbitingscroll 22 is supported byfront end plate 11 throughballs 283. In the embodiment shown in Fig. 1,front end plate 11 and orbitingscroll 22 are formed of light alloy metal, for example, aluminum alloy, to reduce the weight of the apparatus. As a result, fixed and orbitingcover plates 284 and 285 are disposed on the inner end surface offront end plate 11 and the end surface ofend plate 221 to prevent wear ofindentations 281 and 282.
Agrease seal mechanism 29 is placed between the outer peripheral portion ofend plate 221 of orbitingscroll 22 and the inner end surface offront end plate 11. Also, bearing 24 which is located athollow interior 224 oftubular member 223 and bearing 23 which is located within opening 111 have a grease seal mechanism. Therefore, a space defined byfront end plate 11 and axial end surface ofend plate 221 is sealed off. Grease, which is enclosed within space, is retained to lubricate rotation preventing/thrust bearingdevice 28.
A connectinghole 31 is formed throughend plate portion 121 of cup shapedcasing 12. Connectinghole 31 connects between asuction space 141 ofinner chamber 14, which is defined between outer side wall of orbitingspiral element 222 and the inner side wall of cup shapedcasing 12, and acenter space 125 of bothspiral elements 122 and 222. Connectinghole 31 is formed in a circular shape as shown in Figs. 2a-2d, however,hole 31 may be formed in an ellipse shape as shown in Fig. 3. Avalve member 32 is seated in connectinghole 31 for closinghole 31. Valvemember 32 is connected to asolenoid 33 through aplunger 34. Acoil spring 35 is placed betweenvalve member 32 andsolenoid 33, thereforevalve member 32 is usually pushed againsthole 31 to closehole 31 and controlled by the operation ofsolenoid 33. In this embodiment as shown in Fig. 1,solenoid 33 andplunger 34 are located within ahousing 125 which is formed integral with cup shapedcasing 12. Aspace 36 in whichsolenoid 33 andplunger 34 are located is connected tooutlet port 123 through ahole 37.
Referring now to Figs. 2a-2d, the operation of the apparatus will be explained below. As shown in Fig. 2a, fixedspiral element 122 and orbitingspiral element 222 interfit at an angular and radial offset with a small radial gap. The fluid, for example, the air introduced throughinlet port 124 flows intosuction space 141 ofinner chamber 14 of cup shapedcasing 12, and into a space A formed by the inner side wall of orbitingspiral element 222 and the outer side wall of fixedspiral element 122 and a space B formed by the outer side wall of orbitingspiral element 222 and the inner side wall of fixedspiral element 122. The relative position of the spiral elements after thedrive shaft 15 rotates 90° is shown in Fig. 2b. The outer side wall of terminal end of orbitingspiral element 222, now fits against the inner side wall of cup shapedcasing 12, since the outer side wall of orbiting spiral element has an annular shape. Thus, the space B is sealed off by the inner side wall of cup shapedcasing 12 and the outer side wall of orbitingspiral element 222. However, since the diameter of end plate 221 (the outline ofend plate 221 is shown by dotted line in Fig. 2a) is formed smaller than the diameter of cup shapedcasing 12 to permit orbital motion of orbitingscroll 22 within cup shapedcasing 12, space B is axially connected with theinner chamber 14 of cup shapedcasing 12. Accordingly, the pump operation does not start in this stage.
The relative position of the spiral elements afterdrive shaft 15 further rotates 90° is shown in Fig. 2c. Spaces A and B are still connected axially to thesuction space 141 ofinner chamber 14. Therefore, this stage is still in a sucking condition. Whendrive shaft 15 rotates 270° (see Fig. 2d) the inner side wall or orbitingspiral element 222 comes into contact with point P, on the outer side wall of fixedspiral element 122 and the outer side wall of orbitingspiral element 222 comes into contact with point P₂ on the inner side wall of fixedspiral element 122 to seal off spaces A and B. Since both spiralelements 122 and 222 having approximately 1 and 3/4 turns or revolutions, upon passage of the spiral elements from the stage as shown in Fig. 2c to the stage as shown in Fig. 2d, two spaces A and B are connected to thecenter space 125 of spiral elements which is connected withoutlet port 123. As a result, the fluid within spaces A and B flows intocenter space 125 and is reduced in the volume. Upon further rotation ofdrive shaft 15, the fluid within spaces A and B is discharged to an external fluid circuit throughoutlet port 123 by reduction of volume of spaces A and B.
In the case that the apparatus is used as a supercharger for engine of vehicle, operation of the connecting hole will be described below.
The starting or accelerating situation of vehicle, the engine requires the supercharged air for power up. In this situation,solenoid 33 is not operated, so that connecting hole.31 is closed byvalve 32. Therefore, the apparatus is normally operated so as to supply the supercharged air to engine for saving consumption of fuel.
Furthermore, in the case that the vehicle drives at a constant speed, the supercharged air is not required by driving engine.Solenoid 33 is operated through a detecting device (not shown), so thatvalve 32 is moved to the axial direction bysolenoid 33 throughplunger 34. Therefore, connectinghole 31 is opened by movement ofvalve 32. In this situation, the fluid withinsuction space 141 flows intocenter space 125 and/or dischargeport 123 through connectinghole 31 and/orhole 37. The function of the apparatus is thus stopped. The engine operates at a normal condition.
Fig. 4 shows another embodiment of this invention in which the configuration of the connecting hole and the control mechanism of hole are modified. Similar parts are represented by the same reference numerals as in embodiment shown in Fig. 1.Solenoid 33 is fixed on the outside of cup shapedcasing 12. Connectinghole 31 formed throughend plate portion 121 has a certain axial length andvalve 32 is movably fitted within connectinghole 31.Valve 32 is axially moved within connecting hole by operation ofsolenoid 33, so as to form a fluid passageway connecting betweensuction space 141 andcenter space 125 along the inner surface of thevalve 32. The fluid passageway for leaking compressed fluid tosuction space 141 is controlled by movement ofvalve 32. The displacement volume of the apparatus is thus controlled.

Claims

1. A scroll type fluid displacement apparatus including a housing (10) having an inlet port (124) and an outlet port (123), a fixed scroll (122) joined with said housing (10) and having a first end plate (121) from which a first wrap (122) extends into an operative interior area (14) of said housing (10), an orbiting scroll (22) having a second end plate (221) from which a second wrap (222) extends, said first and second wraps (122, 222) interfitting at an angular and radial offset to make a plurality of line contacts to define at least one pair of fluid pockets within said operative interior area, a driving mechanism (15-151-152) connected to said orbiting scroll (22) to drive said orbiting scroll (22) in an orbital motion, and a rotation preventing means (28) for preventing the rotation of said orbiting scroll (22) so that the volume of fluid pockets changes during the orbital motion of said orbiting scroll (22), characterized by an opening portion (31) formed on said first end plate (12) for connecting with a lower pressure space (141) of the operative interior and a center space (125) of said wraps (122,222), and a control means (32) for controlling the opening and closing of said opening portion (31) to control the operation of said apparatus.

2. The scroll type fluid displacement apparatus of claim 1 wherein said first end plate (121) is formed integral with an end plate portion of said housing (10).

3. The scroll type fluid displacement apparatus of claim 1 wherein said control means includes a valve member (32) fitted in said opening portion, solenoid (33) controlled by the external environment, and a plunger (34) connected between said valve member (32) and solenoid (33).

4. The scroll type fluid displacement apparatus of claim 3 wherein said opening portion (31) has an axial length and said valve member is disposed movable within said opening portion (31).