EP2565457A2

EP2565457A2 - Vane-type compressor

Info

Publication number: EP2565457A2
Application number: EP12182075A
Authority: EP
Inventors: Tomoyasu Takahashi; Takanori Teraya; Takaaki Nakamura; Isao Yamada; Michihiro Hori
Original assignee: Valeo Japan Co Ltd
Current assignee: Valeo Japan Co Ltd
Priority date: 2011-08-30
Filing date: 2012-08-28
Publication date: 2013-03-06
Also published as: JP2013050038A; CN102966543B; BR102012021909A2; EP2565457A3; CN102966543A

Abstract

A vane-type compressor with a reduced coating amount of a solid lubricant used for forming a solid lubricant film on an outer peripheral surface of a rotor is provided. In a vane-type compressor (1) including at least: a cylinder 8a which is housed in a housing (2), and has a complete round inner peripheral surface; a complete round rotor (4) which is housed in the cylinder (8a) such that the center (P1) of the rotor (4) is arranged at a position offset from the center (P2) of the cylinder (8a); and a shaft (3) which is press-fitted into a through hole (4a) formed in the rotor (4), a solid lubricant film (30) is formed on an outer peripheral surface (4b) and a side surface (4c) of the rotor (4), and a thickness (L) of the solid lubricant film (30) is set to a value which falls within a range from 10 µm to 20 µm from an initial stage without applying finish working so that a coating amount of the solid lubricant can be relatively reduced.

Description

BACKGROUND OF THE INVENTION

1. FIELD OF THE INVENTION

The present invention relates to a vane-type compressor which is used in a refrigerating cycle or the like of a vehicle-use air conditioner, for example.

2. DESCRIPTION OF THE RELATED ART

In a vane-type compressor which is used in a refrigerating cycle of an air conditioner for a vehicle, to achieve the enhancement of both performance and reliability, conventionally, various measures and methods have been taken for controlling a clearance between an inner peripheral surface of a cylinder and an outer peripheral surface of a rotor to a proper state.
For example, in a vane-type compressor where a rotor in which odd number of vanes are arranged is assembled to an elliptical cylinder as shown in Fig. 1 of JP-A-2004-211651 (patent literature 1), a compressive action is performed alternately at compressive portions positioned on both sides in the radial direction from the center of a shaft. Accordingly, even when a clearance between the shaft and a bearing which supports the shaft is set as small as possible, the rotor assembly alternately vibrates along the ellipse short-axis direction of the elliptical cylinder within a range of the clearance. To be more specific, the rotor assembly vibrates in such a manner that an outer peripheral surface of the rotor and an inner peripheral surface of the cylinder on a top dead center side are separated from each other thus increasing the clearance, while the outer peripheral surface of the rotor and the inner peripheral surface of the cylinder on a side opposite to the top dead center approach each other thus decreasing the clearance.
It is desirable to minimize the clearance between the outer peripheral surface of the rotor and the inner peripheral surface of the cylinder for decreasing leaking of a working fluid (refrigerant gas) from a gap between the outer peripheral surface of the rotor and the inner peripheral surface of the cylinder. However, the rotor assembly vibrates as described above and hence, when the clearance between the outer peripheral surface of the rotor and the inner peripheral surface of the cylinder in the ellipse short-axis direction of the elliptical cylinder is excessively small. Accordingly, there is a possibility that the outer peripheral surface of the rotor and the inner peripheral surface of the cylinder are brought into contact with each other in the ellipse short-axis direction of the elliptical cylinder.
To ensure the reliability of such a vane-type compressor while allowing the contact between the outer peripheral surface of the rotor and the inner peripheral surface of the cylinder, a solid lubricant film may be formed by applying by coating a solid lubricant such as polytetrafluoroethylene (hereinafter PTFE) to one or both of the inner peripheral surface of the elliptical cylinder and the outer peripheral surface of the rotor. Although the purpose may differ, in a gas compressor shown in Patent Literature 1, there is disclosed the structure where a solid lubricant film made of a fluororesin or the like is formed on one or both of an inner peripheral surface of an elliptical cylinder and an outer peripheral surface of a rotor.
When the rotor where the solid lubricant film is formed over the whole circumference is used, a thickness of the solid lubricant film is also taken into account in addition to the degree of accuracy of shapes of respective parts and hence, irregularities in clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the rotor become relatively large. Accordingly, a specific controlling process is adopted in general where in conformity with an actually measured size of one of the inner peripheral surface of the cylinder and the outer peripheral surface of the rotor, the other is machined such that the clearance takes a proper value thus controlling the clearance (hereinafter "matching process").

SUMMARY OF THE INVENTION

However, to perform the above-mentioned matching process in forming the vane-type compressor which adopts an elliptical cylinder as shown in Patent literature 1, it is difficult to form an elliptical shape with sufficient accuracy by grinding or lathe machining and hence, usually, matching process is performed by grinding an outer peripheral surface of a rotor having a cylindrical shape on a rotor assembly side.
Along with such matching process, a solid lubricant film which is formed on the outer peripheral surface of the rotor in an initial stage has a thickness of approximately 100 µm including a surplus amount, for example, by taking into account the deformation of the rotor at the time of press-fitting a shaft and the machining allowance. Accordingly, when expensive PTFE is applied by coating as a solid lubricant, there arises a drawback that it is necessary to use a large amount of PTFE although the PTFE is to be removed in machining process. Further, there also arises a drawback that a solid lubricant film made of PTFE with a relatively large thickness of approximately 100 µm, for example, cannot be formed unless an operation of coating a lubricant and hardening the coated lubricant by burning which is operated in plural divided stages is repeated several times, for example, three times.
Accordingly, it is an object of the present invention to provide a vane-type compressor which can relatively reduce a coating amount of a solid lubricant used for forming a solid lubricant film on an outer peripheral surface of a rotor.
A vane-type compressor according to the present invention includes: a housing which has a suction opening and a discharge opening, and forms an outer shell; a cylinder which is integrally formed with the housing or is formed as a body separate from the housing, and has a complete round inner peripheral surface; a complete round rotor which is housed in the cylinder such that the center of the rotor is arranged at a position offset from the center of the cylinder; vane grooves which open on an outer peripheral surface of the rotor; vanes which are housed in the vane grooves in an extensible and retractable manner while being brought into slide contact with the inner peripheral surface of the cylinder; a shaft which is combined with the rotor by being press-fitted into the rotor thus forming a rotor assembly and transmits power from the outside to the rotor; and bearing portions which are provided in the housing and rotatably supports the shaft, and the vane-type compressor is characterized in that a solid lubricant film is formed on the outer peripheral surface of the rotor, and the rotor assembly is housed in the cylinder without applying machining process to the solid lubricant film. Further, the vane-type compressor is characterized in that a clearance between the rotor assembly and the cylinder is controlled by machining only the inner peripheral surface of the cylinder based on a size of a predetermined position of the rotor assembly. Here, for example, PTFE or the like is used as a solid lubricant. Further, a solid lubricant film is formed by applying a solid lubricant or the like by coating.
Due to such a constitution, the cylinder having the complete round inner peripheral surface is used and hence, it is possible to apply matching process by machining the inner peripheral surface of the cylinder with a lathe. Accordingly, it becomes unnecessary to machine the outer peripheral surface and the side surface of the rotor for the matching process by grinding, and also it becomes unnecessary to apply by coating a surplus solid lubricant to the rotor assembly by taking into account machining allowance and hence, a coating amount of a solid lubricant can be relatively decreased.
Further, the vane-type compressor is constituted of the cylinder having the complete round inner peripheral surface and the complete round rotor which is housed in the cylinder such that the center of the rotor is arranged at a position offset from the center of the cylinder and hence, the rotor is always pushed toward a side opposite to a top dead center due to a pressure in the cylinder. Therefore, even when a clearance between the shaft and the bearing portion is large, there is no possibility that the rotor assembly vibrates. Accordingly, it is unnecessary to perform matching process for controlling the clearance between the shaft and the bearing portion to a proper value with respect to the bearing portion and hence, the clearance can be controlled to a proper value by only applying matching process to the inner peripheral surface of the cylinder based on a numerical value from one point on the outer peripheral surface of the rotor to an outer peripheral surface of the shaft on a side opposite to a side where the point on the outer peripheral surface of the rotor exists.
The vane-type compressor according to the present invention is characterized in that a solid lubricant film is also formed on either side surface of the rotor on which a through hole into which the shaft is inserted opens, and the rotor assembly is housed in the cylinder also without applying machining process to the solid lubricant film on the side surface of the rotor. In this manner, by forming the solid lubricant film also on the side surface of the rotor without applying finish working in the same manner as the outer peripheral surface of the rotor, a solid lubricant can be applied by coating to the outer peripheral surface and the side surface of the rotor simultaneously.
The vane-type compressor according to the present invention is characterized in that a thickness of the solid lubricant film of the rotor falls within a range from 10 µm to 20 µm. An optimal thickness of the solid lubricant film is 15 µm, for example.
The vane-type compressor according to the present invention is characterized in that a plain bearing is used as a bearing of each bearing portion. Due to such a constitution, compared to a case where a needle bearing is used as a bearing portion, a relatively large clearance between the bearing portion and the shaft can be allowable. Further, unlike the case where the needle bearing is used as the bearing portion, the direct measurement becomes possible when the position of one point on the bearing portion positioned on a side opposite to one point positioned on the inner peripheral surface of the cylinder is measured.
The vane-type compressor according to the present invention is characterized in that a side block which constitutes the housing is integrally formed with the cylinder. When the side block is integrally formed with the cylinder in this manner, by applying matching process such that a bottom surface of the cylinder (corresponding to a side surface of the rotor) is made to match with a length of the rotor after forming the solid lubricant film, a thrust clearance between the side block and the rotor can be easily controlled.
The vane-type compressor according to the present invention is characterized in that a recessed portion which is indented in the axial direction of the through hole is formed on the side surface of the rotor around an opening periphery of the through hole. Due to such a constitution, the recessed portion can be utilized as an area where it is unnecessary to take into account sliding or interference with a part which faces the recessed portion.
As described above, according to the inventions described in Claim 1 to Claim 7, with the use of the cylinder having the complete round inner peripheral surface, matching process can be applied by machining the inner peripheral surface of the cylinder with a lathe. Therefore, unlike a conventional case where matching process is performed on a rotor assembly side by grinding an outer peripheral surface and a side surface of a rotor, matching process can be performed on a cylinder side. Accordingly, it is enough for the solid lubricant film formed on the rotor assembly to have a minimum thickness and hence, it is unnecessary to apply a surplus solid lubricant to the rotor assembly by coating whereby a coating amount of the solid lubricant can be relatively decreased. Thus, a manufacturing cost of the vane-type compressor can be reduced.
Conventionally, as explained above, a surplus amount of a thickness of a solid lubricant film formed on a rotor assembly is machined off and hence, it is difficult to control a thickness of the solid lubricant film within a proper thickness being from 10 µm to 20 µm, preferably a thickness of 15 µm, and eventually, the thickness of the solid lubricant film even of a complete product conventionally comes to 40 µm, for example. According to the present invention described in Claim 3, the solid lubricant film formed on the rotor assembly can surely have the thickness which falls within a range from 10 µm to 20 µm, and more preferably a thickness of 15 µm.
Particularly, according to the invention described in Claim 2, by forming the solid lubricant film also on the side surface of the rotor without machining process after coating process in the same manner as the outer peripheral surface of the rotor, a solid lubricant can be applied by coating to both the outer peripheral surface and the side surface of the rotor simultaneously and hence, an operation of applying a solid lubricant to the rotor by coating can be performed efficiently and rapidly.
Particularly, according to the invention described in Claim 4, unlike a case where a needle bearing is used as a bearing portion, the direct measurement becomes possible at the time of measuring the position of one point on the inner periphery of the bearing portion. Further, a plain bearing can be used with a relatively large clearance compared to a needle bearing. In case that a needle bearing is used as the bearing portion, for controlling a clearance between the bearing portion and the shaft to a predetermined clearance value, it is necessary to perform matching process with respect to an outer diameter of the shaft in conformity with an inner diameter of the bearing portion. However, according to the present invention, with the use of the plain bearing as the bearing portion, it becomes unnecessary to control the clearance between the bearing portion and the shaft, and finally matching process on a rotor assembly side can be made completely unnecessary along with the technical feature described in Claim 1 that the cylinder has the complete round inner peripheral surface.
Further, when the side block is integrally formed with the cylinder as described in Claim 5, by performing matching process such that the bottom surface of the cylinder (corresponding to the side surface of the rotor) is made to match with a length of the rotor after the formation of the solid lubricant film, a thrust clearance between the rear side block and the rotor can be also easily controlled.
Particularly, according to the invention described in Claim 6, the indented recessed portion is formed on the side surface of the rotor around an opening periphery of the through hole into which the shaft is inserted and hence, this recessed portion can be used as an area where it is unnecessary to take into account sliding or interference with a part which faces the recessed portion. For example, by using the recessed portion formed on the side surface of the rotor as a support portion at the time of press-fitting the shaft into the rotor, even when the periphery of the support portion is damaged or bulged due to a press-fitting load, it is unnecessary to take into account slide failure or interference with the side block. Accordingly, it is unnecessary to apply a surplus solid lubricant by coating to the side surface of the rotor and, then, to remove the surplus solid lubricant by machining process by taking into account the deformation of the side surface of the rotor or a damage of the solid lubricant film generated at the time of press-fitting the shaft and hence, a coating amount of the solid lubricant can be further reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1a and Fig. 1b are cross-sectional views showing one example of a vane-type compressor according to the present invention, wherein Fig. 1a is a cross-sectional view of the vane-type compressor taken so as to make a discharge opening viewable, and Fig. 1b is a cross-sectional view of the vane-type compressor taken so as to make a suction opening viewable.
Fig. 2 is a cross-sectional view taken along a line A-A in Fig. 1b.
Fig. 3 is a cross-sectional view with a part broken away showing the internal constitution of the vane-type compressor according to the present invention.
Fig. 4a to Fig. 4c are explanatory views showing a rotor assembly which constitutes the vane-type compressor according to the present invention and the constitution of a rotor which constitutes a part of the rotor assembly, wherein Fig. 4a is a perspective view of the rotor assembly, Fig. 4b is a perspective view of the rotor, and Fig. 4c is an explanatory view showing a thickness of a solid lubricant film formed on an outer surface of the rotor.
Fig. 5 is an explanatory view showing the reference in setting a clearance between an outer peripheral surface of the rotor and an inner peripheral surface of a cylinder.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, an embodiment of the present invention is explained in conjunction with attached drawings.
Fig. 1a to Fig. 4c show one example of a vane-type compressor used in a refrigerating cycle of a vehicle-use air conditioner, for example. The vane-type compressor 1 includes: a shaft 3; a rotor 4 which is fixed to the shaft 3 and is rotated along with the rotation of the shaft 3; and a first housing member 8 and a second housing member 9 which define a compression space 18 described later together with the rotor 4. A housing 2 is constituted of the first housing member 8 and the second housing member 9. A part (A) shown in Fig. 4a formed by assembling the rotor 4 to the shaft 3 is also referred to as a rotor assembly.
In this embodiment, the first housing member 8 is formed of: a cylinder 8a which houses the rotor 4 therein; and a rear-side block 8b which is positioned on a rear side of the cylinder 8a in the axial direction of the shaft 3, is integrally formed with the cylinder 8a, and closes a rear side of the cylinder 8a. Although not shown in the drawing, the cylinder 8a may be constituted as a body separate from the rear-side block 8b, that is, the cylinder 8a may not be constituted as a portion of the first housing member 8, and alternatively, the cylinder 8a may be integrally formed with a front-side block 9a.
The rotor 4 which is housed in the cylinder 8a is formed into a circular columnar shape having a complete round shape in cross section, and as shown in Fig. 4b, a through hole 4a into which the shaft 3 can be press-fitted is formed at the center P1 of the complete round shape. Further, as shown in Fig. 4b, the rotor 4 includes a plurality of (two in this embodiment) vanes 6 inserted into a plurality of (two in this embodiment) vane grooves 5 which open on an outer peripheral surface of the rotor 4. The vane grooves 5 open not only to the cylinder 8a but also to a front-side block 9a and a rear-side block 8b, and back pressure chambers 5a are defined in bottom portions of the vane grooves 5 which are arranged on a depth side in the slide direction of the vanes 6. Accordingly, the back pressure chambers 5a are also configured to open to the front-side block 9a side and the rear-side block 8b side. As shown in Fig. 2, the vane 6 slides on an inner peripheral surface of the cylinder 8a in such a manner that side surfaces of the vane 6 slide on inner side surfaces of the vane groove 5, and a distal end of the vane 6 projects from the vane groove 5 in an extensible and retractable manner. A recessed portion 4d formed on a side surface 4c of the rotor 4 is described later.
As shown in Fig. 2, the inner peripheral surface of the cylinder 8a is formed into a complete round shape having an inner diameter size larger than an outer diameter size of the rotor 4. The rotor 4 is housed in the inside of the cylinder 8a in such a manner that the center P2 of the cylinder 8a and the center P1 of the rotor 4 are offset from each other so as to form a minute clearance at one portion in the circumferential direction between the outer peripheral surface of the rotor 4 and the inner peripheral surface of the cylinder 8a (a portion where the cylinder 8a and the rotor 4 approach each other most closely: top dead center P3). An offset amount between the center P2 of the cylinder 8a and the center P1 of the rotor 4 is approximately 1/2 of the difference between the inner diameter size of the cylinder 8a and the outer diameter size of the rotor 4, for example. In this manner, the rotor 4 is housed in the inside of the cylinder 8a and hence, a compression space 18 is defined between the inner peripheral surface of the cylinder 8a and the outer peripheral surface of the rotor 4. The compression space 18 is divided into a plurality of compression chambers 19 by being partitioned by the vanes 6 which are housed in the plurality of vane grooves 5 formed in the rotor 4, and a volume of each compression chamber 19 is configured to be changed due to the rotation of the rotor 4.
The second housing member 9 is an integral body constituted of: the front-side block 9a which is brought into contact with a front-side end surface of the cylinder 8a; and a shell 9b which extends from the front-side block 9a in the axial direction of the shaft 3 and surrounds outer peripheral surfaces of the cylinder 8a and the rear-side block 8b. Further, the second housing member 9 is connected to the first housing member 8 by means of connecting jigs 7 such as bolts. Further, by inserting the first housing member 8 into a rear-side opening portion 9d of the shell 9b thus fitting the first housing member 8 into the shell 9b, a front side of the cylinder 8a is closed by the front-side block 9a, and the rear-side opening portion 9d of the shell 9b is closed by the rear-side block 8b.
Further, with respect to the second housing member 9, a pulley 20 to which rotational power is transmitted from a power source (not shown in the drawing) of a vehicle by way of a belt (not shown in the drawing) is rotatably and exteriorly mounted on a boss portion 9c which is integrally formed with the front-side block 9a, and rotational power is transmitted to the shaft 3 from the pulley 20 by way of an electromagnetic clutch 21. Further, a suction opening 11 and a discharge opening 12 for a working fluid (refrigerant gas) are formed in the second housing member 9, and the suction opening 11 is communicated with a suction space 14 which is defined by a space portion 14a formed in the second housing member 9 and a recessed portion 14b formed on the cylinder 8a.
The shaft 3 is rotatably supported on the front-side block 9a of the second housing member 9 and the rear-side block 8b of the first housing member 8 by way of plain bearings 23, 24 which constitute bearing portions and are held by the front-side block 9a and the rear-side block 8b respectively. Further, at a position in the vicinity of a proximal end of the boss portion 9c of the second housing member 9, a seal member 13 is interposed between the shaft 3 and the inner peripheral surface of the second housing member 9 so as to prevent leaking of a working fluid to the outside from an opening of the boss portion 9c.
Further, a suction port 25 which is communicated with the suction space 14 and discharge ports 26 which are communicated with a discharge space 15 are formed on the peripheral surface of the cylinder 8a corresponding to the compression space 18. Accordingly, when the cylinder 8a is fitted into the shell 9b, the suction space 14 is communicated with the compression chamber 19 through the suction port 25, the discharge space 15 whose both end sides are partitioned by flange portions 8c, 8d is formed between the outer peripheral surface of the cylinder 8a and the inner peripheral surface of the shell 9b, and the discharge space 15 is communicable with the compression chamber 19 through the discharge ports 26. The discharge ports 26 is opened or closed by a discharge valve 27 which is housed in the discharge space 15. The discharge space 15 is communicated with an oil separator 16 through a through hole 28 formed in the flange portion 8d. Further, the oil separator 16 is communicated with the discharge opening 12.
Due to the above-mentioned constitution, in the vane-type compressor 1, when rotational power from the power source not shown in the drawing is transmitted to the shaft 3 by way of the pulley 20 and an electromagnetic clutch 21 so that the rotor 4 is rotated, a working fluid which flows into the suction space 14 through the suction opening 11 is sucked into the compression space 18 through the suction port 25. A volume of the compression chamber 19 partitioned by the vanes 6 in the compression space 18 is changed along with the rotation of the rotor 4 and hence, the working fluid which is confined between the vanes 6 is compressed, and is discharged into the discharge space 15 from the discharge ports 26 through the discharge valves 27. The working fluid discharged into the discharge space 15 is moved in the circumferential direction along the outer peripheral surface (the inner peripheral surface of the shell 9b) of the cylinder 8a and flows substantially around the periphery of the cylinder 8a and, thereafter, is guided into an oil separation chamber of the oil separator 16 formed in the rear-side block 8b through the through hole 28 formed in the flange potion 8d. Thereafter, oil is separated from the working fluid in the process where the working fluid whirls in the inside of the oil separation chamber of the oil separator 16 and, then, the working fluid is discharged to an external circuit from the discharge opening 12.
As shown in Fig. 4c, a solid lubricant film 30 is formed on the outer peripheral surface 4b and the side surface 4c of the rotor 4 shown in Fig. 4b. As a solid lubricant for forming the solid lubricant film 30, PTFE is used, for example.
A clearance value W between the outer peripheral surface of the rotor 4 and the inner peripheral surface of the cylinder 8a is suitably controlled by a following method as shown in Fig. 5.
Firstly, a rotor-assembly-side size R identified by the distance from a point S1 positioned on the outer peripheral surface 4b of the rotor 4 to a point S2 positioned at the opposite side of the point S1 on a peripheral surface of the shaft 3 is measured.
On the other hand, with respect to the cylinder 8a, a cylinder-side size C identified by the distance from a point S3 positioned at the opposite side of a direction toward which the center P2 of the cylinder 8a is offset from the center P1 of the rotor 4 (lower side in Fig. 5) on the inner peripheral surface of the cylinder 8a before finish machining process is applied to a point S4 positioned at the opposite side of the point S3 on the inner peripheral surface of the plain bearing 24 is measured.
A value obtained by subtracting a numerical value of the rotor-assembly-side size R from a numerical value of the cylinder-side size C corresponds to a numerical value of the clearance W between the outer peripheral surface of the rotor 4 and the inner peripheral surface of the cylinder 8a during the compressor operation. Accordingly, an optimum numerical value C' (not shown in the drawing) is decided based on the numerical value R and the numerical value C which are measured in advance such that a numerical value of W becomes a preferred value (for example, 20 µm), and the cylinder 8a is machined for matching process such that a numerical value of the cylinder-side size C which is the size of the cylinder 8a from the point S3 to the point S4 takes such an optimum numerical value C'.
The reason why the clearance W can be controlled by applying matching process to the cylinder 8a is that the inner peripheral surface of the cylinder 8a is formed into a complete round shape so that machining process to a cylinder 8a side can be performed using a lathe. As described above, although the center P1 of the rotor 4 is offset from the center P2 of the cylinder 8a, by holding and rotating the cylinder 8a while chucking the cylinder 8a in an offset manner, the inner peripheral surface of the offset cylinder 8a can be machined by a lathe. Further, in measuring the above-mentioned cylinder-side size C, if the bearing portion were constituted of a needle bearing, a plurality of needles (rollers) would be exposed to an inner peripheral surface of the bearing portion and hence, the point S4 could not be directly measured. In this embodiment, however, the bearing portion is constituted of the plain bearing 24 and hence, the point S4 which becomes the reference can be directly measured.
Further, if the needle bearing were used as the bearing portion, it would be necessary to control a clearance between an inner diameter of the bearing portion and a shaft within a predetermined clearance range by taking into account reliability of needles. Accordingly, it would be necessary to measure an inner diameter size of an actual bearing portion and, thereafter, to perform matching process for adjusting a machined amount with respect to an outer diameter size of the shaft to acquire a predetermined clearance. In this embodiment, by constituting the bearing portion using the plain bearings 23, 24, a control of the clearance between the bearings 23, 24 and the shaft 3 becomes unnecessary.
Accordingly, unlike the prior art, it is no more necessary to perform matching process on a rotor 4 side and, eventually, on a rotor assembly A side and hence, it is no more necessary to set a thickness L of the solid lubricant film 30 which is formed on the outer peripheral surface and the side surface of the rotor 4 to a thickness of approximately 100 µm, for example, which includes a surplus thickness by taking into account a machining allowance.
Further, in this embodiment, as shown in Fig. 4a and Fig. 4b, the recessed portion 4d which is indented in the axial direction of the through hole 4a is formed on the side surface 4c of the rotor 4 around an opening periphery of the through hole 4a. The recessed portion 4d constitutes a support portion for supporting a press-fitting load in forming the rotor assembly A by press-fitting the shaft 3 into the rotor 4 on which the solid lubricant film 30 is formed. Although there exists a possibility that the periphery of the support portion bulges or the solid lubricant film is damaged due to a press-fitting load when the shaft 3 is press-fitted into the rotor 4, these damages can be confined in the recessed portion 4d and hence, there exists no possibility that the rotor 4 interferes with the side blocks 8b, 9a and causes sliding failure. Accordingly, even when the solid lubricant film 30 is formed on the rotor 4 before the shaft 3 is press-fitted into the rotor 4, it is unnecessary to take into account damages on the solid lubricant film 30 and hence, it is no more necessary to set a thickness of the solid lubricant film 30 to a thickness which includes a surplus thickness also from this point of view.
Further, on the outer peripheral surface 4b and the side surface 4c of the rotor 4, a thickness of the solid lubricant film 30 can be set to a preferred size from the beginning, for example, a size within a range from 10 µm to 20 µm (for example, an optimum size of 15 µm) and hence, a coating amount of the solid lubricant is relatively decreased, and finish working for setting a thickness of the solid lubricant film to a preferred size can be also made unnecessary. Accordingly, a manufacturing cost of the vane-type compressor 1 can be reduced.
Further, as shown in Figs. 1a and 1b, the first housing member 8 may be an integral body formed of the cylinder 8a and the rear-side block 8b. Due to such constitution, both a thrust clearance and a radial clearance can be continuously formed by machining at a stroke from the cylinder 8a to the rear-side block 8b in accordance with sizes of an actual rotor assembly A. Accordingly, a working time can be shortened. Further, although an error in size is liable to be generated each time a part is held by a tool when the process is divided into steps, a possibility that the errors are generated due to the division of the process into steps is decreased so that the accuracy of the rotor assembly can be enhanced.

Claims

A vane-type compressor (1) comprising:
a housing (2) which has a suction opening (11) and a discharge opening (12), and forms an outer shell;
a cylinder (8a) which is integrally formed with the housing (2) or is formed as a body separate from the housing (2), and has a complete round inner peripheral surface;
a complete round rotor (4) which is housed in the cylinder (8a) such that the center (P1) of the rotor (4) is arranged at a position offset from the center (P2) of the cylinder (8a);
vane grooves (5) which open on an outer peripheral surface of the rotor (4);
vanes (6) which are housed in the vane grooves (5) in an extensible and retractable manner while being brought into slide contact with the inner peripheral surface of the cylinder (8a);
a shaft (3) which is combined with the rotor (4) by being press-fitted into the rotor (4) thus forming a rotor assembly (A) and transmits power from the outside to the rotor (4); and
bearing portions (23, 24) which are provided in the housing (2) and rotatably supports the shaft (3),
characterized in that a solid lubricant film (30) is formed on the outer peripheral surface of the rotor (4), and the rotor assembly (A) is housed in the cylinder (8a) without applying machining process to the solid lubricant film (30).
The vane-type compressor (1) according to Claim 1, characterized in that a solid lubricant film (30) is also formed on either side surface of the rotor (4) on which a through hole (4a) into which the shaft (3) is inserted opens, and the rotor assembly (A) is housed in the cylinder (8a) also without applying machining process to the solid lubricant film (30) on the side surface of the rotor (4).
The vane-type compressor (1) according to Claim 1 or 2, characterized in that a thickness of the solid lubricant film (30) falls within a range from 10 µm to 20 µm.
The vane-type compressor (1) according to Claim 1, 2 or 3, characterized in that a plain bearing is used as a bearing of each bearing portion (23, 24).
The vane-type compressor (1) according to Claim 1, 2, 3 or 4, characterized in that a side block which constitutes the housing is integrally formed with the cylinder (8a).
The vane-type compressor (1) according to Claim 2, 3, 4 or 5, characterized in that a recessed portion (4d) which is indented in the axial direction of the through hole (4a) is formed on the side surface of the rotor (4) around an opening periphery of the through hole (4a).
The vane-type compressor (1) according to Claim 1, 2, 3, 4, 5 or 6, characterized in that a clearance between the rotor assembly (A) and the cylinder (4) is controlled by machining only the inner peripheral surface of the cylinder (4) based on a size of a predetermined position of the rotor assembly(A).