AU643273B2

AU643273B2 - Scroll type fluid machine

Info

Publication number: AU643273B2
Application number: AU76453/91A
Authority: AU
Inventors: Takahisa Hirano; Takayuki Iio; Yoshiharu Morita; Toshiyuki Shikanai
Original assignee: Churyo Engineering Co Ltd; Mitsubishi Heavy Industries Ltd
Current assignee: Churyo Engineering Co Ltd; Mitsubishi Heavy Industries Ltd
Priority date: 1990-08-16
Filing date: 1991-05-10
Publication date: 1993-11-11
Anticipated expiration: 2011-05-10
Also published as: JPH04101001A; CA2042204A1; CA2042204C; CN1021590C; KR920004729A; CN1059017A; EP0471425A1; AU7645391A

Description

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT (Original) APPLICATION NUMBER:

LODGED:

COMPLETE SPECIFICATION LODGED:

ACCEPTED:

PUBLISHED:

843273 RELATED ART: S. u*

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NAME OF APPLICANT: ACTUAL INVENTOR(S): MITSUBISHI JUKOGYO KABUSHIKI KAISHA and CHURYO ENGINEERING KABUSHIKI

KAISHA

TOSHIYUKI SHIKANAI TAKAYUKI IIO TAKAHISA HIRANO AND YOSHIHARU MORITA

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ADDRESS FOR SERVICE:, INVENTION TITLE: KELVIN LORD AND COMPANY 4 Douro Place West Perth WA 6005 "SCROLL TYPE FLUID MACHINE" DETAILS OF ASSOCIATED PROVISIONAL APPLICATIONS: NOS: The following statement is a full description of this invention including the best method of performing it known to me/us:-

STANDARD/I

1 2 3 4 6 7 8 9 11 12 13 14 16 17 18 S 19 S 20 21 22 23 23 24 26 27 28 29 a 30 2 The present invention relates to a scroll type fluid machine used as a compressor, an expansion machine and the like.

Fig. 3 shows an example of a conventional scroll type compressor of this sort.

In Fig. 3, a housing 1 consists of a cup-shaped main body 2, a front end plate 4 which is clamped to the main body 2 with bolts (not shown), and a front cover 6 which is clamped to the front end plate 4 with a bolt A rotary shaft 7 extends through the front cover 6 and is rotatably supported by the housing 1 through a bearing 8, provided between the front cover 6 and the rotary shaft 7, and a bearing 9 provided between a boss 7a thereof and the front end plate 4.

A stationary scroll 10 and a revolving scroll 14 are housed inside the housing 1.

The stationary scroll 10 is provided with an end plate 11 and a spiral wrap 12 disposed on the inner surface thereof. The outer peripheral surface of the end plate 11 is brought into close contact with the inner peripheral surface of the cup-shaped main body 2 and clamped with a bolt 13 thereto. The stationary scroll 10 is fixed to the bottom side of the housing 1. Thus, a high pressure chamber 31 is delimited on the outside of the end plate .11, and A low pressure chamber 32 is delimited on the inside thereof.

The revolving scroll 14 is provided with an end plate 15 and a spiral wrap 16 disposed on the inside surface f 1 1 2 3 4 6 7 8 9 11 12 13 14 16 9 17 18 19 *oo 20 t. 21 0 23 25 26 27 28 29 0 3 thereof.

The spiral wrap 16 has substantially the same configuration as the spiral wrap 12.

The revolving scroll 14 and the stationary scroll are eccentric from each other by the radius of revolution. The revolving scroll 14 and the stationary scroll 10 are engaged with each other with their respective spiral wraps 16 and 12 being rotationally displaced 1800 from each other as shown in Figure 3.

A tip seal 17 is disposed on an end surface of the spiral wrap 12. The tip seal 17 is in close contact with the -inner surface of the end plate 15. A tip seal 18 is embedded in the end surface of the spiral wrap 16. The tip seal 18 is in close contact with the inner surface of the end plate 11. The side surfaces of the spiral wraps 12 and 16 are brought into linear contact with each other at a plurality of locations. In this way, a plurality of closed small chambers 19a and 19b are delimited. The closed small chambers 19a and 19b form an approximate point symmetry with respect to the centre of the spiral wraps 12 and 16.

A bushing 21 is rotatably fitted into a cylindrical boss 20. The cylindrical boss 20 projects from the central part of the outer surface of the end plate of the revolving scroll 14 through a rotary bearing 23. An eccentric pin 25 projects from an inner end of the rotary shaft 7 and is rotatably fitted into an eccentric hole 24 bored in the bushing 21. Further, a b~dance weight 27 is fixed to this bushing 21.

1 4 2 A rotation restraining mechanism 26 for restraining 3 axial rotation is arranged between the outer peripheral 4 edge of the outer surface of the end plate 15 and the inner surface of the front end plate 4. The rotation 6 restraining mechanism also acts as a thrust bearing.

7 A sub-balance weight 28 is clamped on the boss 7a of 8 the rotary shaft 7.

9 Thus, when the rotary shaft 7 is rotated, the revolving scroll 14 is driven through the eccentric pin 25, the 11 bushing 21, the rotary bearing 23 and the boss 20, and 12 the revolving scroll 14 revolves in an orbital motion 13 while being restrained from rotating on its axis by 14 means of the rotation restraining mechanism 26.

When the revolving scroll 14 revolves in an orbital 16 motion, the linear contact portion between the spiral 17 wraps 12 and 16 gradually moves toward the centre of

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18 the spiral. As a result, the closed small chambers 19a 19 and 19b move toward the centre of the spiral while reducing the volumes thereof. In keeping with this, 21 gas sucked into the low pressure chamber 32 through a 22 suction port (not shown) is taken into the closed small 23 chambers 19a and 19b from opening portions at the outer 24 peripheral ends of the spiral wraps 12 and 16 and 25 reaches a central chamber 22 while being compressed.

26 Then, the gas passes therefrom through a discharge port 27 29 bored in the central part of the end plate 11 of the 28 stationary scroll 10 and pushes a discharge valve 29 open to discharge into the high pressure chamber 31, and flows out through a discharge port (not shown).

1 2 3 4 6 7 8 9 11 12 13 14 16 6 G 17 18 19 21 20 21 22 23 24 25 26 27 28 29 5 In the above-mentioned conventional scroll type compressor, there is a risk that a high pressure gas in the above-mentioned high pressure chamber 31 can act on the outer surface of the end plate 11 of the stationary scroll 10 during operation, thereby deforming the end plate 11 so that it becomes depressed at the centre thereof.

When the end plate 11 becomes thus deformed, problems such as galling, abnormal friction and seizure on the in:ner surface of the end plate 11, particularly between the central part thereof and the tip surface of the spiral wrap 16 of the revolving scroll 14 and damage at the tip portion of the spiral wrap 16 can occur.

This has necessitated a counter-measure to be taken whereby the thickness of the end plate 11 is increased or the tooth height at the central part of the spiral of the spiral wrap 16 is made lower than at other parts.

However, such a counter-measure results in a lowering of efficiency.

The present invention seeks to provide a scroll type fluid machine which addresses the above-described problems associated with conventional scroll type machines.

In accordance with one aspect of the present invention there is provided a scroll type fluid machine comprising a housing sealed by a substantially cup-shaped main body and a front cover assembly, a stationary scroll and a revolving scroll provided in

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1 2 3 4 -6 7 8 9 11 12 13 14 16 S 2 18 19 19 20 21 22 23 24 S 25 S 26 27 27 28 29 It 0 6 said housing and arranged to engage with each other, said stationary and revolving scrolls having a respective end plate with a respective spiral wrap provided on a respective inner side of each said end plate, said stationary scroll fixed to a bottom side of said housing and said revolving scroll able to revolve in an orbital motion whilst its axial rotation is restrained by rotation restraining means, low pressure chamber forming means which together with said stationary scroll is secured to said housing by bolt means from outside said housing, and a hole provided in said low pressure chamber forming means, wherein said low pressure chamber forming means has an outer peripheral surface sealing with an inner peripheral surface of said cup-shaped main body and said low pressure chamber forming means is disposed at the outside of said end plate of said stationary scroll to partition the inside of said housing into a first low pressure chamber and a high pressure chamber, and said hole communicates at a first end thereof with a discharge port provided at a central part of said end plate of said stationary scroll and said hole opens at a second end thereof to said high pressure chamber to enable said high o'sckarl~e Orf pressure chamber and saidfirA t lcw p zzea-ur ha--ecr to communicate, such that said high pressure chamber is positioned toward said bottom side of said housing and a second low pressure chamber is formed between said end plate of said stationary scroll and said high pressure chamber by said low pressure chamber forming means, and said second low pressure chamber is arranged to communicate with said first low pressure chamber.

6a- 2 3 4 6 7 8 9 11 12 13 14 16 17 18 22 23 23 24 *4 29 In the present invention, the low pressure in the low pressure chamber is applied to the outer surface of the end plate of the stationary scroll with the construction described above. Therefore, deformation of the end plate is prevented or reduced.

1 7 2 As it is evident from the above description, in the 3 present invention the low pressure in the low pressure 4 chamber is applied to the outer surface of the end plate of the stationary scroll, thus preventing or 6 reducing deformation of the end plate.

7 As a result, it is possible to prevent abnormal 8 friction, seizure and galling between the inner surface 9 of the end plate of the stationary scroll and the tip surface of the spiral wrap of the revolving scroll and 11 damage to the spiral wrap, thus improving reliability 12 of the scroll type fluid machine.

13 The present invention will now be described, by way of 14 example, with reference to the accompanying drawings, in which:- 16 Fig. 1 is a longitudinal sectional view showing a first 17 embodiment of a scroll type fluid machine in accordance S 18 with the present invention; 19 Fig 2 is a partial longitudinal sectional view showing 20 a second embodiment of a scroll type fluid machine in 21 accordance with the present invention; and t* 22 Fig. 3 is a longitudinal sectional view of a 23J conventional scroll type compressor.

24 Preferred embodiments of the present invention will be 25 described in detail hereafter illustratively with 26 reference to the drawings.

27 Figures 1 and 2 and the following description of the 28 preferred embodiments use the same reference numerals 29 th\t are used in Figure 3 and the description of the conventional scroll type compressor to denote S 1 8 2 corresponding parts. Accordingly, the description of 3 these parts as described with reference to the 4 conventional scroll type compressor and Fig. 3 applies in like manner to the preferred embodiments of Figs. 1 6 and 2 and so is not herein repeated. Thus, the 7 description of the preferred embodiments of Figs. 1 and 8 2 which follows is directed to the differences between 9 these embodiments and the conventional scroll type compressor previously described herein.

11 Fig. 1 shows a first embodiment of a scroll type fluid 12 machine in accordance with the present invention.

13 A low pressure chamber forming unit 33 is disposed on 14 the outside of an end plate 11 of a stationary scroll 10, and is clamped to a cup-shaped main body 2 together 16 with the stationary scroll 10 by means of a bolt 13.

17 The outer peripheral surface of the unit 33 is 18 installed on an inner peripheral surface of the 19 cup-shaped main body 2 through a seal ring 35 so as to S 20 form an airtight structure. In this way, the inside of 21 the housing 1 of the scroll type fluid machine is 22 partitioned into a low pressure chamber 32 and a high 23 pressure chamber 31 by means of the unit 33. Further, 24 a low pressure chamber 34 is delimited between the end 25 plate 11 of the stationary scroll 10 and the high presUre. cAvbier cowMumnicas nA ASe. loe 26 pressure chamber 31 by means of the unit 33. The lowA 27 pressure chamber 32 via a through hole 36.

28 A hole 37, which at one end thereof communicates with a 2# discharge port 29, is bored at the central part of the unit 33, 1 9 2 A tip of a cylindrical boss 38 (of the unit 33) which 3 projects toward the end plate 11 around the hole 37 is 4 attached onto the outer surface of the end plate 11 via a seal ring 39 so as to form an airtight structure.

6 Further, a discharge valve 30 opens and closes the outlet 7 end of the hole 37. This outlet end opens to the high 8 pressure chamber 31.

S9 The hole 37 thus enables the discharge port 29 and the high pressure chamber 31 to communicate. The remaining 11 construction of the scroll type fluid machine of the 12 first embodiment shown in Fig. 1 is similar to that of 13 the conventional scroll type compressor shown in Fig. 3.

14 Accordingly, it is to be understood that the description Of this remaining construction that was described with 16 reference to the conventional scroll type compressor and 17 Fig. 3 applies in like manner to the preferred 18 embodiments of Fig. 1. When the scroll type fluid machine 19 shown in Fig. 1 is in operation, a low pressure gas 20 sucked into the low pressure chamber 32 enters the low 21 pressure chamber 34 via the through hole 36. Accordingly, 22 the low pressure gas in the low pressure chamber 34 acts 23 on the outer surface of the end plate 11 of the S 24 stationary scroll 10, and the pressing force applied to 9.* 25 the end plate 11 becomes substantially less as compared 26 with a conventional scroll type compressor, thereby I 27 preventing or reducing deformation of the end plate 11.

28 Fig. 2 shows a second embodiment of a scroll type fluid -29 machine in accordance with the present invention, wherein 1 9a 2 the hole 37 is enlarged, the discharge valve 30 ~s 3 disposed at the bottom of the hole 37, and the 9. 9.

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9 ~*69 9 6 99 9 *h 9 1 2 3 4 6 7 8 9 11 12 13 14 16 17 S. 18 18 19 21 .0 22 22 27 o 0 0 0 29Q 10 outlet of the discharge port 29 is opened and closed by means of the discharge valve In the second embodiment of the scroll type fluid machine shown in Fig. 2, the top clearance volume is reduced and performance of the machine may be improved.

The remaining construction of the scroll type fluid machine of the second embodiment shown in Figure 2 is similar to that of the conventional scroll type compressor shown in Fig. 3 and the preferred embodiment of the scroll type fluid machine shown in Fig. 1.

Accordingly, it is to be understood that the description of this remaining construction that was described with reference to the conventional scroll type compressor of Fig.

3 and the preferred embodiment of Fig. 1 applies in like manner to the preferred embodiment of Figl. 2.

The remainder of the operation of the scroll type fluid machines of the first and second embodiments shown in Figs.

1 and 2, respectively, is similar to that of the conventional scroll type compressor shown in Fig. 3.

Modifications and variations such as would be apparent to a skilled addressee are deemed within the scope of the present invention.

Claims

2. A scroll type fluid machine according to Claim 1, wherein said low pressure chamber forming means is provided with a cylindrical boss which projects toward said end plate of said stationary scroll around said hole and is attached to the outside surface of said end plate of said stationary scroll by first seal means.
3. A scroll type fluid machine according to Claim 1 or 2, wherein discharge valve means is provided at said second end of said hole.
4. A scroll type fluid machine according to Claim 1 or 2, wherein said hole is of enlarged size and discharge valve means is provided at said discharge port near said first end of said hole.
5. A scroll type fluid machine according to any one of Claims 1 to 4, wherein second seal means is provided between said outer peripheral surface of said low pressure chamber forming means and said inner peripheral surface of said cup-shaped main body.
6. A scroll type fluid machine substantially as hereinbefore described with reference to Fig. 1 or Fig. 2 of the accompanying drawings. 4 0 4 S 606 4 S S 0 S. 0 S i 0 S.r 4* 0 I 1 2a- 2 DATED MAY 26 1993 3 MITSUBISHI JUKOGYO KABUSHIKI 4 KAISHA and CHURYO ENGINEERING KABUSHIKI 6 KAISHA 7 By their Patent Attorneys *8 KELVIN LORD AND COMPANY 9 PERTH, WESTERN AUSTRALIA. 11 12 13 14 :06. 16 17 18 A 19 21 22 23 24 26 O 28 2'9 ~7 ;rl
7. ABSTRACT According to the present invention, there is provided a scroll type fluid machinery in which a sta- tionary scroll and a revolving scroll provided with spiral wraps set up on end plates, respectively, are engaged with each other and housed in a housing, the stationary scroll is fixed to the housing, and the revolving scroll is made to revolve in a solar motion while checking the rotation *L* S* "on its axis by means of a mechanism for checking rotation
9. on its axis, wherein a low pressure chamber forming unit which partitions the inside of the housing into a low .a i pressure chamber and high pressure chamber of above- mentioned machihery isk disposed on the outside of the en plate of the stationary scroll, and a low pressure chamber which communicates with' the low pressure chamber is formed between the eni plate of the stationary scroll and the high pressure chamber by means of this low pres- a sure chamber forming unit, thereby to prevent or reduce deformtion of the end plate of the stationary scroll. *4 6 13