AU601485B2 - Rotary vane-type fluid pressurizing unit - Google Patents

Description

I i: COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION FOR OFFICE USE Form Short Title: Int. Cl: 601 4 Application Number: Lodged: Complete Specification-Lodged: Accepted: Lapsed: Published: Priority: I is do'-imeilt contains the.

a1ifl2~idt.1s~ made iin..~.

i n9 and is curnicc 1.: Related Art: TO BE COMPLETED BY APPLICANT Name of Applicant: Address of Applicant: Actual Inventor: Address for Service: ATSUG! MOTOR PARTS COMPANY,

LIMITED

1370, Onna, Atsugi-shi, Kanagawa-ken,

JAPAN

Seiji Akaike Masao Yasuda and Shinya Matsumoto r r. t- e GRIFFITH HASSEL FRAZER 71 YORK STREET SYDNEY NSW 2000

AUSTRALIA

r -yl Complete Specification for the invention entitled: ROTARY VANE-TYPE FLUID PRESSURIZING UNIT The following statement is a full description of this invention, including the best method of performing it known to me/us:- 2354A:rk ROTARY VANE-TYPE FLUID PRESSURIZING

UNIT

The present invention relates to a rotary vane-type fluid pressurizing unit, such as a fluid pump, a compressor and so forth. More specifically, the invention relates to an improved construction of rotary vane-type fluid pressurizing unit, such as a compressor forming a part of cooling unit in an automotive cooler system or an automotive air conditioner system, for example. Further particularly, the invention relates to •cc a rotary fluid pressurizing unit which includes a cam ring assembly and can prevent a cam ring in the cam ring r:"te assembly from being deformed.

Vane-type rotary compressor has been employed in an automotive cooler system or air conditioner system .a1 for feeding a pressurized cooling medium, iuch as t "C refrigerant, to a cooling circuit including a condenser, evaporator and so forth. Such vane-type rotary compressor comprises a cam ring assembly housed within a compressor housing for generating a pressurized cooling medium. As is well known, the cam ring assembly comprises a cam ring defining non-circular, such as elliptic rotor chamber to house therein an engine driven rotor. The cam ring assembly further comprises a front plate and back plate to be fixed to both axial ends of the cam ring for sealingly defining the rotor chamber.

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A rotor shaft connected to the rotor housed within the rotor chamber extends through the front plate of the cam ring assembly and the compressor housing to be connected to an engine output shaft via a known pulley-belt power train. In order to rotatably support the rotor shaft, a cylindrical boss section extends in axial direction from the front plate. A bearing assembly is interposed between the outer periphery of the rotor shaft and the inner periphery of the cylindrical boss section for reducing resistance against rotation of the rotor shaft 1 cand thus assure smooth driving of the rotor.

In order to support the rotor shaft in stable condition, the boss section has to be provided sufficient bending stress and thus to be rigid enough.

In the prior art, since the boss section is integrally formed with the front plate, the rigidity of the front plate was necessarily high to exhibit high being stress.

When such high rigidity front plate is sealingly fixed onto the axial front end of the cam ring, it tends to lead deformation of cam ring due to error in parallelism 2b between mating surfaces of the front plate and cam ring.

This, in other words, requires substantial accuracy in surfacing of the cam ring and front plate in order to prevent the cam ring from being deformed due to error in pal-Ilelism. Otherwise, the deformation of the cam ring brings 1fluctuation of top clearance to lower the compressor performance and durability, and lower yield 2 -C 00C C rC r t C 9 C C

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In order to avoid such defect, there has been proposed an improved construction of the cam ring assembly which has a flexible front plate. Such flexible front plate has provided lower rigidity than the cam ring to cause deformation when an error in parallelism between the mating surfaces of the cam ring and the front plate exists. This deformation of the front plate absorbs deformation stress to be exerted on the cam ring, otherwise, and thus successfully prevent fluctuation of the top clearance. However, on the other hand, such construction of the front plate is necessarily formed separately from the cylindrical boss section which receives the rotor shaft. Separatingly forming the front plate and the boss section requires assembling operation of the front plate and the cylindrical part which forms the boss section. This apparently increases process step in assembling the rotary compressor.

Therefore, production ability and efficiency can be lowered to cause increase of the production cost.

20 According to one aspect of the invention, a rotary vane-type pressurising unit comprising: a housing defining an internal space; a cam ring assembly disposed within said internal space to define a low pressure chamber and a high pressure chamber in said internal space at opposite sides thereof, which low pressure chamber is communicated with a low S pressure fluid source to introduce a low pressure working fluid, and which high pressure chamber being connected to a working load, said cam ring assembly including an annular cam ring defining a working chamber introducing low pressure working fluid from said low pressure chamber and feeding a high pressure working fluid into said high pressure chamber; a ro.xr disposed within said working chamber, said rotor carrying a plurality of vanes, each of which is movable toward and away from the periphery of said working chamber, said rotor being connected to a driving power source via a drive shaft to be driven for compressing the working fluid in said working chamber;

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first and second closure members sealingly fixed at axially displaced ends of said cam ring for defining said working chamber in a fluid tight fashion, said first closure member being formed of a thin, resiliently deformable plate with an opening through which said drive shaft extends; and cylindrical support means, forming part of said housing, for rotatably supporting said drive shaft.

According to another aspect of the invention, a rotary vane-type pressurising unit comprising: a housing defining an internal space; a cam ring assembly disposed within said internal space to define a low pressure chamber and a high pressure chamber in said internal space at opposite sides thereof, which low pressure chamber is communicated with a low 1115 pressure fluid source to introduce a low pressure working fluid, and which high pressure chamber is connected to a working load, said cam ring assembly including an annular cam ring defining a working chamber introducing low pressure working fluid from said low pressure chamber and feediig a high pressure working fluid into said high pressure chamber; a rotor disposed within said working chamber, said rotor carrying a plurality of vanes each of which is movable toward and away from the periphery of said working chamber, said rotor being connected to a driving power source via a drive shaft to be driven for compressing the working fluid in said working chamber; a closure member sealingly fixed to an end of said cam ring for closing an open end of said cam ring, said closure member being secured to said end in fluid tight fashion and being formed with an opening through which said drive shaft extends, said closure member being formed of a thin, resiliently deformable plate so that it may conform to a mating surface of said cam ring; and cylindrical support means, forming part of said housing for rotatably supporting said drive shaft.

An advantage of the present invention is that it provides an improved construction of the rotary vane-type fluid pressurising unit, such as a vane-type rotary 1 t I' C r S3S/KLS 4 r -j 4.

I compressor, which can eliminate the aforementioned drawbacks of the prior art and thus exhibits substantially high production yield and efficiency with lower cost.

Another advantage of the present invention is that it provides an improvement in and related to a vane-type rotary conipressor which can successfully avoid deformation of a cam ring in a cam ring assembly for maintaining top clearance between the sealing edge of vane carried by a rotor and a cam surface formed on the inner periphery of a rotor chamber.

In the preferred construction, the cylindrical support is formed integrally with the housing. The housing comprises a housing body which defines the internal space opening at one end of the housing body, and a head cover which is rigidly fixed onto the housing body for sealingly "15 closing the opening end, and the cylindrical support is formed integrally with the head cover. The axial end of the cylindrical support has a surface mating with the first closure member for restricting deformation of the first closure member in a direction away from the rotor.

The present invention will be understood more fully from the detailed description given herebelow and from the accompanying drawings of the preferred

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In the drawings: Fig. 1 is a sectional view of the preferred embodiment of a vane-type rotary compressor according to the present invention; and.

Fig. 2 is an exploded perspective view of a major part of the preferred embodiment of the vane-type rotary compressor of Fig. 1.

Referring now to the drawings, particularly to r Fig. 1, a vane-type rotary compressor has a front plate 100, a head cover 102, a housing 106 and a cam ring 108.

SThe front plate 100 comprises a single element which is simply formed of metal plate and is rigidly secured onto the front end of the cam ring 106 by means of fastening bolts 108. The rear end of the cam ring 106 is closed by means of a back plate 110 for defining a clearance within the cam ring for rotatably receiving therein a rotor 112 with a plurality of vanes 114. As will be appreciated, the vanes 114 are received within radially extending slits 116 formed in the rotor 112. Each vane 114 is movable relative to the corresponding slit 116 so that it may protrude from the outer periphery of the rotor 112 and rotatingly and sealingly contact with the inner periphery of the cam ring.

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1 The head cover 102 is formed with an axially extending cylindrical boss-like portion 118. The boss-like portion 118 is arranged coaxially with an outer cylindrical portion 120. The rear ends of the boss-like portion 118 and the cylindrical portion 120 are sealingly engaged with the front plate 100 for defining therebetween an aspiration chamber 122 which is connected to an inlet port 124 for introducing therethrough a refrigerant gas. The aspiration chamber 122 is communicated with working chambers 126 via a suction opening (not shown) which opens on the cam surface of the front plate 100. The working chamber is, in turn, communicated with a discharge chamber 128 defined in the housing 104 by the cam ring 106 and the rear plate 110 via discharge port formed through the 5 rear plate. The discharge chamber 128 is in communicated with a discharge port 130. The operation for condensing the refrigerant gas for condensation and thereby removing heat is performed in a per se known manner by rotation of the rotor 112.

O The rotor 112 is integrally formed with a drive shaft and a support shaft 134. The drive shaft 132 extends through the boss-like portion 118 of the head cover 102 to project outwardly from the head cover. A bearing assembly 136 is disposed between the inner periphery of the boss-like portion 118 and the outer periphery of the drive shaft 132. Similarly, the RA 47 7 9

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support shaft 134 extends from the plane surface of the rotor at the side opposite to the plane surface from which the drive shaft extends. The support shaft 134 is received within a boss-like portion 138 of the rear plate. A bearing 140 is disposed between the inner periphery of the boss-like portion 138 of the rear plate and the outer periphery of the support shaft. In the preferred embodiment, the bearings 136 and 140 comprises roller type needle bearings. An engine driven pulley t 142 is associated with the drive shaft 132 via a known ":"tib clutch assembly 144 which releasably engages the pulley to the drive shaft. Therefore, as clutch is engaged, I¢ the rotor 112 is driven by an automotive engine.

The preferred embodiment of a seal assembly 150 is disposed between the inner periphery of the boss-like portion 118 of the head cover 102 and the outer periphery of drive shaft. The seal assembly 150 is so designed as to establish liquid tight and gas-tight seal therebetween.

In the construction set forth above, the front plate 100 is formed of a thin metal plate and simply in a form an annular disk. The front plate 100 is thus resiliently deformable to absorb bending force by resilient deformation. As seen from Figs. 1 and 2, the front plate 100 mates with the axis end surface 106a of the cam ring and rigidly fixed thereon by means of the fastening btlts 108 extending through openings 100a

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formed through the front plate 100 and extending axially. The front plate 100 also defines a central opening 152 through which the drive shaft 132 of the rotor 112 extends.

The central opening 152 is arranged in alignment with an axial opening 154 of the inner cylindrical section 118 which serves as the boss section for rotatably receiving the drive shaft and the bearing t 136. The inner cylindrical section has the axial rear *f t end 156 mating with the outer surface' 100b of the front plate 100. This rear axial end surface 156 thus crestricts deformation of the front plate 100 and thus maintains sealing contact between the inner surface 100c of the front plate 100 and the axial end surface of the rc rotor 112. On the other hand, the outer cylindrical s.15 section 120 also has rear axial end surface mating with the outer surface 100b of the front plate to restrict deformation of the front plate. Therefore, with the contact between the rear axial end surfaces 118a and 120a of the inner and outer cylindrical sections 118 and 120 of the head cover 102, sealing engagement between the front plate 100 and the cam ring 106 and the rotor 112 can be assured.

On the other hand, with the sealingly contacting the rear axial end surfaces 118a and 120a of inner and outer cylindrical sections 118 and 120, the aspiration chamber 122 is defined. The aspiration R A 4'

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chamber 122 is communicated with the working chamber 126 via the section opening as set forth above. The aspiration chamber 122 is further communicated with the working chamber via a return passage 156 which is connected to a recess 158 formed in the rear end of the outer cylindrical section 120 via a through opening 160 formed through the front plate 100. A pressure responsive valve means 162 is disposed in the return passage 156 for releaving excessive pressure in the working chamber. The pressure responsive valve means is I responsive to the pressure balance between the gc 1 Caspiration chamber 122 and the discharge chamber 128 to VC which the pressurized fluid is introduced. Namely, when the shown embodiment of the compressor is used in the automotive air conditioner system, the pressure of the 15 refrigerant gas may be maintained at a given level i unless the pressure to be supplied to the evaporator via t r: er Sthe condenser becomes excessive. When the pressure becomes excessive, the unvaporized liquid state I*n refrigerant tends to be introduced into the aspiration 0 chamber to lower than pressure in the aspiration chamber. Then the pressure responsive valve becomes active to return part of the refrigerant gas in the working chamber to the aspiration chamber to maintain the pressure in the discharge chamber at an optimum level.

As will be appreciated from the above, since the present invention employs a thin metal plate in a simple construction as the front plate for closing the front end opening of the cam shaft, deformation of the cam ring which leads variation or fluctuation of the top clearance of the rotor vanes, can be successfully eliminated even when production error in surfacing of the surfaces 100c and 106a mating each other occurs to cause error in parallelism. Furthermore, since the boss section for rotatingly supporting the drive shaft of the rotor is integrally formed with the head cover, the c1 construction of the front plate can be simplified. In addition, by providing the boss section in the head cover, the front plate is not require substantial rigidity since no substantial load may be applied. This enables the front plate to be flexible enough to absorb bending force.

Therefore, the present invention fulfills all of the objects and advantages sought therefore.

While the present invention has been disclosed in terms of the preferred embodiment in order to facilitate better understanding of the invention, it should be appreciated that the invention can be embodied in various ways without departing from the principle of the invention. Therefore, the invention should be understood to include all possible embodiments and modifications to the shown embodiments which can be embodied without departing from the principle of the invention set out in the appended claims.

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Claims (9)

1. A rotary vane-type pressurising unit comprising: a housing defining an internal space; a cam ring assembly disposed within said internal space to define a low pressure chamber and a high pressure chamber in said internal space at opposite sides thereof, which low pressure chamber is communicated with a low pressure fluid source to introduce a low pressure working fluid, and which high pressure chamber being connected to a working load, said cam ring assembly including an annular cam ring defining a working chamber introducing low pressure working fluid from said low pressure chamber and feeding a high pressure working fluid into said high pressure chamber; S 15 a rotor disposed within said wr:rking chamber, said r rotor carrying a plurality of vanes, each of which is movable toward and away from the periphery of said working chamber, said rotor being connected to a driving power source via a drive shaft to be driven for compressing the working fluid in said working chamber; first and second closure members sealingly fixed at r, [axially displaced ends of said cam ring for defining said t working chamber in a fluid tight fashion, said first closure S member being formed of a thin, resiliently deformable plate with an opening through which said drive shaft extends; and cylindrical support means, forming part of said c C housing, for rotatably supporting said drive shaft. i c

2. A rotary vane-type pressurising unit as set forth in claim 1, wherein said cylindrical support means is formed integrally with said housing.

3. A rotary vane-type pressurising unit as set forth in claim 2, wherein said housing comprises a housing body which defines said internal space opening at one end of said housing body, and a head cover which is rigidly fixed onto 13 r' said housing body for sealingly closing said opening end, and said cylindrical support means is formed integrally with said head cover.

4. A rotary vane-type pressurising unit as set forth in claim 3, wherein an axial and of said cylindrical support means has a surface mating with said first closure member for restricting deformation of said first closure member in a direction away from said rotor.

A rotary vane-type pressurising unit comprising: F a housing defining an internal space; a cam ring assembly disposed within said internal Sr space to define a low pressure chamber and a high pressure chamber in said internal space at opposite sides thereof, S which low pressure chamber is communicated with a low t t pressure fluid source to introduce a low pressure working fluid, and which high pressure chamber is connected to a working load, said cam ring assembly including an annular cam ring defining a working chamber introducing low pressure working fluid from said low pressure chamber and feeding a high pressure working fluid into said high pressure chamber; a rotor disposed within said working chamber, said rotor carrying a plurality of vanes each of which is movable toward and away from the periphery of said working chamber, said rotor being connected to a driving power source via a drive shaft to be driven for compressing the working fluid in said working chamber; c a closure member sealingly fixed to an end of said cam ring for closing an open end of said cam ring, said closure member being secured to said end in fluid tight P fashion and being formed with an opening through which said Sdrive shaft extends, said closure member being formed of a thin, resiliently deformable plate so that it may conform to a mating surface of said cam ring; and cylindrical support means, forming part of said housing for rotatably supporting said drive shaft. 14

6. A rotary vane-type pressurising unit as set forth in claim 5, wherein said cylindrical support means is formed integrally with said housing.

7. A rotary vane-type pressurising unit as set forth in claim 6, wherein said housing comprises a housing body which defines said internal space opening at one end of said housing body, and a head cover which is rigidly fixed onto said housing body for sealingly closing said opening end, and said cylindrical support means is formed integrally with said head cover.

8. A rotary vane-type pressurising unit as set forth in claim 7, wherein an end of said cylindrical support means has a surface mating with said closure member for *restricting deformation of said closure member in a direction away from said rotor.

9. A rotary vane-type pressurising unit substantially as hereinbefore described with reference to the accompanying drawings. DATED this 12th day of June 1990 ATSUGI MOTOR PARTS COMPANY LIMITED By their Patent Attorney GRIFFITH HACK CO T .7 3S/KLS 15 J