WO2011096918A1

WO2011096918A1 - Vane-type rotary machine with reduced wear and friction loss

Info

Publication number: WO2011096918A1
Application number: PCT/US2010/022829
Authority: WO
Inventors: Michel Tramontana; Alexander Shkolnik
Original assignee: Tramontana Technology Group (Holding) Gmbh
Priority date: 2010-02-02
Filing date: 2010-02-02
Publication date: 2011-08-11

Abstract

A fluid-operated vane type rotary machine having a stator, a rotor installed in the stator, and a plurality of vanes slidingly installed in radial slots of the rotor. In order to reduce friction between the tips of the vanes and the inner surface of the machine chamber formed in the stator, the tips are provided with rollers or roller bearings which have a rolling contact with the inner surface of the machine chamber. The machine may be provided with a seal member, which also may have a roller or bearing. In both cases the roller or bearing is caulked on the end face of the vane and projects only for an amount sufficient for reliable rolling contact with the stator.

Description

VANE-TYPE ROTARY MACHINE WITH REDUCED WEAR AND FRICTION LOSS

FIELD OF THE INVENTION

The present invention relates generally to air pressure motors, turbines, vacuum pumps, engines, compressors, etc. More specifically, the invention relates to a rotary machine with one or several chambers, each chamber having an inlet and outlet for pressurized air, gas, fluid and/or fuel. In particular, the invention relates to a vane- type rotary machine driven by pressurized fluid and characterized by reduced wear of parts participating in mutual contact and by reduced loss of power during friction.

DESCRIPTION OF THE PRIOR ART

Vane type rotary machines driven into rotation by pressurized fluid and having vanes slidingly moveable in radial slots of a rotor are known in the art. During operation, the outer tips of the vanes are shifted radially outward under effect of springs and/or by centrifugal force and are brought into contact with the inner surface of the stator during rotation of the rotor.

For example, US Patent No. 3,191,503 issued in 1965 to G. Fuehrer discloses a rotor assembly for a fluid-operated device, wherein in order to simplify the structure of the device and provide constant contact of the outer tips of the vanes with the inner surface of the stator, elliptically deformed resilient O-rings, made, e.g., of polyurethane, are placed into the radial slots under the vanes for constantly urging the vanes toward the stator.

US Patent No. 4,032,269 issued in 1977 to R. Sheth discloses rotary sliding vane compressor with a resilient bodies placed in the slots of the rotor for biasing the vanes outwardly to maintain the vane tips in sliding engagement with the cylindrical wall of the rotor chamber which forms the gas working space. The rotor is received within a cylindrical chamber of stator and mounted such that its axis is offset with respect to the cylindrical stator axis, thus providing a generally crescent- shaped gas working space. The rotor is in sliding contact with a portion of the cylindrical wall, and this contact point divides the low-pressure side from the high-pressure side. An inlet port communicates with one side of the gas working space and a discharge port communicates with the opposite side. Gas is trapped between adjacent vanes and carried around through the compression zone. The volume of each pocket or compartment, as defined between adjacent vanes and the rotor and stator surfaces, becomes smaller as it approaches the discharge port thus compressing the gas trapped therein. The slots are canted at a certain angle with respect to the actual radial direction, and the resilient bodies eliminate the use of metal springs and dampen noise during operation.

US Patent No. 5,007,778 issued in 1991 to T. Hillestad, et al. discloses a portable power tool with a pneumatic motor having a rotor provided with six symmetrically spaced radial slots. Each of these slots receives a radial vane having a convex inner surface. The floor of each slot has a curved shape that coincides with the convex inner surface of a vane. When the motor is engaged, the vanes are forced outward so that the outer surface bears against the inner surface of the chamber. The vanes divide the chamber into asymmetrical lobes. As the rotor turns in the clockwise direction, the radial vanes move radially outward to maintain engagement with the surface of the lobed chamber until they reach the maximum extension. Accordingly, the radial vanes, the outer surface of the rotor, and inner surface of the stator chamber define progressively expanding cavities, i.e., the lobes. The resulting expansion of the compressed air produces continuous rotation of the rotor. Compressed air enters the lobed stator chamber at an inlet opening formed at the bottom of the stator ring and exits through an exit port formed in the front plate at the top of the chamber. The air enters through one of the openings for a clockwise rotation of the rotor and through another opening for counter clockwise rotation.

US Patent No. 4,385,873 issued in 1983 to H. Ritchel discloses a rotary vane-type motor and a compressor or pump in which an eccentrically mounted rotor having sliding vanes rotates within a stationary main housing or stator. The stator is, in turn, defined by a pair of opposed shells, each shell essentially being a half cylinder such that the internal working surface of the stator against which the vanes move forms essentially two opposing and identical circular paths or segments. The movement path of the vanes may be further controlled by rollers affixed thereto and adapted to engage a freely idling race ring mounted inside of the hollow rotor and supported by means of a stationary crankshaft. In this added way the vanes pass the internal working surface of the stator without contact because of a controlled clearance, and the centrifugal force of the vanes acting against the stator housing is eliminated for increase in efficiency and operation at higher speeds. The outer ends of the vanes are provided with seals of appropriate construction such that a sliding sealing engagement is made with the stator.

In all devices of the type described above the tips of the vanes are in sliding contact with the inner surface of the stator chamber. At high rotational speed this leads to extensive wear of the vanes and the inner surface of the stator chamber.

Attempts have been made heretofore to solve the above problem by various methods. For example, Japanese Unexamined Patent Application Publication No. 62-060993 disclosed in 1987 (inventor: K. Fujino) describes a wear-resistant vane for use in conjunction with the vane-type rotary machines. The vane has a composite structure wherein the surface of the vane body is coated with a special film that improves wear resistance and allows for low friction.

US Patent No. 5,560,741 issued in 1996 to T. Edwards discloses a non-contact vane- type fluid-displacement machine having a rotor with a plurality of vanes slidingly mounted for reciprocable movement in a radial slots of the rotor so that the outer tips of the vanes are maintained in a non-contacting relationship with the annular interior surface of the stator due to the use of a vane guide assembly that controls the radial movement of the vanes within the slots of the rotor. The vane guide assembly includes a pair of anti-friction roller bearings arranged as mirror images of one another in annular channels defined in the oppositely facing surfaces of the front and intermediate endplates of the stator housing. The above-described vane guide assembly serves to precisely control, with generation of only minimum mechanical friction, the radial motion of the vanes so that the vanes remain in exceedingly close gas sealing proximity, but essentially frictionless non-contacting relationship, with the interior primary surface of the stator housing body.

Another way of reducing the friction force between the radial vanes and the inner surface of the stator chamber is the use of so-called "roller vanes" employed, e.g., in roller vane pumps, or the like, wherein the vanes are made in the form of rollers. For example, US Patent No. 3,447,476 issued in 1969 to E. Parris discloses a vane-type fluid rotary machine wherein vanes are made in the form of rollers located in radial slots of the rotor so that the rollers have rolling contact with the inner surface of the stator chamber on sides of the plates and the circumferential area.

US Patent No. 4,284,392 issued in 1981 to R. Pareja discloses a roller pump comprising a cylindrical housing and a cylindrical rotor arranged eccentrically within the housing and having push rods arranged radially within the rotor for assisting in forcing radial motion of the rollers within the rotor during rotation of the rotor within the housing. A camshaft shaft is arranged within the housing, and the push rods make contact with the periphery of the camshaft shaft in order to provide radial motion of the push rods during rotation of the rotor. The pump is intended for handling highly viscous products.

One disadvantage of conventional roller- vane type rotary machines is that the roller vanes have radial displacements that are limited to the magnitude of the roller radius. Another disadvantage is that in the construction of the type shown in US Patent No. 4,284,392 the portions of the rotor periphery beyond the rollers are still in sliding contact with the inner surface of the stator chamber.

In view of the above, it is an object of the present invention to provide a vane-type fluid-operated rotary machine that is free of the above disadvantages and ensures low- fiction rolling contact of the radial vanes located in radial slots of the rotor with the inner surface of the stator chamber on the entire 360° turn of the rotor. It is another object to provide a vane-type fluid operated rotary machine that combines advantages of roller-vane rotary machines with advantages of large- volume chambers of conventional plate- vane type rotary machines. SUMMARY OF THE INVENTION

The vane type rotary machine of the present invention may comprise a pneumatic motor, turbine, vacuum pump, compressors, engine, etc. In general, as a conventional vane-type rotary machine, the machine of the invention comprises a stator the interior of which forms a machine chamber having a substantially cylindrical inner wall, a cylindrical rotor eccentrically or coaxially installed in the stator and having a plurality of radial slots, and plate-like vanes slidingly installed in the radial slots and brought into contact with the surface of the cylindrical inner wall of the stator by resilient members and/or by centrifugal forces developed during rotation of the rotor. The rotor has linear contact with the aforementioned cylindrical inner wall of the stator. Thus, during rotation of the rotor, a plurality of closed working chambers for fluid is formed between the inner wall of the stator, the outer surface of the rotor, and the vanes, or between the surfaces of the rotor, stator, vanes and the line of contact between the rotor and stator. One working chamber nearest to the line of contact has a fluid inlet port through which a fluid under pressure is fed to this working chamber, while the other working chamber nearest to the line of contact and located on the side opposite to the first working chamber has a fluid outlet port through which the fluid is expelled from the machine chamber.

Unique to the rotary machine of the invention is the securing of a body of rotation, e.g., a roller, a roller bearing, or a group of balls (hereinafter referred to as "rollers") on the end of each vane for providing a rolling contact between the tip of the vane and inner surface of the stator chamber. In contrast to conventional roller vanes formed by free rollers, the rollers of the invention are fixed against radial movement relative to the vanes and have only rotational freedom. This is achieved by caulking the rollers on the tips of the vanes so that only a very small part of the roller projects from the tip of the vane. Since the roller has a linear contact with the inner cylindrical surface of the stator, this contact provides a seal between the fluid inlet and fluid outlet chambers.

According to one aspect of the invention, the roller may comprise an elongated roller bearing or a needle bearing and the projecting part of such a roller is the projecting part of the outer ring of the bearing. According to another aspect of the invention, in the contact point between the rotor and stator the latter can be provided with a sealing member, e.g., a spring-loaded seal pad made from a wear-resistant and low-friction material. When worn-out, these pads can be replaced.

In order to prevent sliding contact between the outer surface of the rotor and the stator at the point of their mutual contact on a part of revolution of the rotor between the adjacent vanes, the pad may also be provided with a roller caulked on its end face on the rotor side. The other end of the pad is biased towards the rotor surface. In such a construction the rotor and starter will always have a rolling contact. The pad's roller may also be made as a roller bearing or the like.

However, although the projection of the rollers on the tips of the vanes and on the end face of the seal pad is very small, e.g., about 1/5 to 1/1000 of the roller diameter, a provision of rollers on the tips of the vanes and on the pad may cause a shock at the moment when two rollers collide.

In order to solve this problem, according to one more aspect of the invention, the rotor is provided with a circumferential groove or grooves which are made in such a position that allows for a small portion of the pressurized inlet fluid to flow under the roller of the seal pad for raising it up and out of contact with the anticipated collision with the approaching vane roller when the letter is about to assume the position of the contact line between the rotor and the stator.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a cross-sectional view of the rotary machine according to one aspect of the invention.

Fig. 2 is a three-dimensional view of the vane used in the machine of Fig. 1.

Fig. 3 is a longitudinal sectional view of the roller-vane assembly unit used in the rotary machine according to another aspect of the invention.

Fig. 4A is a longitudinal cross-sectional view of a roller-vane assembly unit used in the rotary machine according to another aspect of the invention, wherein the roller is supported at both ends by ball bearings.

Fig. 4B is a sectional view of the unit of Fig. 4A along the line A-A.

Fig. 5 is a cross sectional view of the roller- vane assembly unit used in the rotary machine according to another aspect of the invention, wherein an antifriction and wear-resistant seal pad is used between the rotor and stator.

Fig. 6 is a cross-sectional view of the rotary machine according to another aspect of the invention, wherein a roller is installed in a seal pad, and a groove is made in the periphery of the rotor for raising the pad by a portion of compressed gas.

Fig. 7 is a fragmental cross-sectional view of a rotary machine according to another aspect of the invention, wherein the roller alone is used a seal member.

Fig. 8 is s top view of the rotor used in the machine of Fig. 6.

Fig. 9 is a cross-sectional view of the rotary machine according to another aspect of the invention, wherein a bypass channel is provided in the stator for reducing pressure in the chamber above the spring-loaded sealing member.

Fig. 10 is a cross-sectional view of the rotary machine according to another aspect of the invention, wherein two symmetrical systems are used for preventing collision of the rollers on diametrically opposite sides of the rotor.

DETAILED DESCRIPTION OF THE INVENTION

The vane type rotary machine according to one aspect of the present invention is shown in Figs. 1 and 2, where Fig. 1 is a cross-sectional view of the rotary machine, and Fig. 2 is a three-dimensional view of the vane. The vane type rotary machine of the invention (hereinafter referred to as "rotary machine") shown in Fig. 1 is designated in its entity by reference numeral 20 and may comprise a pneumatic motor, turbine, vacuum pump, compressor, Stirling engine, etc.

In general, as a conventional vane-type rotary machine, the rotary machine 20 comprises a stator 22 the interior of which forms a machine chamber 24 having a substantially cylindrical inner wall 26, a cylindrical rotor 28 eccentrically installed in the stator 22 and having a plurality, e.g. four, of radial slots 30a, 30b, 30c, and 30d, and plate-like vanes 32a, 32b, 32c, and 32d slidingly installed in the respective radial slots 30a, 30b, 30c, and 30d. The vanes are brought into contact with the surface of the cylindrical inner wall 26 of the stator 22 by means constantly biasing the vanes to contact with the inner surface of the machine chamber of the stator, such as respective resilient members 34a, 34b, 34c, and 34d and/or by centrifugal forces developed during rotation of the rotor 28. The rotor 28 has linear contact with the

aforementioned cylindrical inner wall 26 of the stator 22.

Thus, during rotation of the rotor 28, a plurality of closed working chambers 36a, 36b, 36c, and 36d is formed between the inner wall 26 of the stator 22, the outer surface 38 of the rotor 28, and the vanes 32a, 32b, 32c, and 32d, or between the surfaces of the rotor 28, stator 22, vanes 32a, 32b, 32c, and 32d, and a line 40 of contact between the rotor 28 and stator 22. One working chamber 36b nearest to the line of contact 40 has a fluid inlet port 42 through which a fluid under pressure, e.g., compressed air, is fed to this working chamber 36b, while the other working chamber 36a nearest to the line of contact 40 and located on the side opposite to the first working chamber 36b has a fluid outlet port 44 through which the fluid is expelled from the machine chamber 24.

Unique to the rotary machine 20 of the invention is the securing of securing of a body of rotation, e.g., a roller 46 (Fig. 2) on the end face of each vane for providing a rolling contact between the tip of the vane and inner surface of the stator chamber. Thus, a roller 46a is installed on the tip of the vane 32a, a roller 46b is installed on the tip of the vane 32b, a roller 46c is installed on the tip of the vane 32c, and a roller 46d is installed on the tip of the vane 32d.

In contrast to conventional roller vanes of the type used in conventional roller vane pumps and formed by free rollers (see, e.g., US Patent No. 4,284,392), the rollers 46a, 46b, 46c, and 46d of the invention are fixed against radial movement relative to the vanes 32a, 32b, 32c, and 32c, respectively, and have only rotational freedom. This is achieved by caulking the rollers on the tips of the vanes as shown in Fig. 2 so that only a very small part of the roller projects from the tip of each vane. Since the roller 42b has linear contact with the inner cylindrical surface 26 of the stator 22 over the entire length of the rotor 28, this contact provides a seal between the fluid inlet and fluid outlet chambers 36b and 36a, respectively.

According to one aspect of the invention, as shown in Fig. 3, which is a longitudinal sectional view of the roller-blade assembly unit, the roller 48 may comprise an elongated roller bearing or a needle bearing that consists of an inner ring 48a, an outer ring 48b, and a roller 48c. Reference numeral 50 designates a vane. The projecting part of such a roller is the projecting part of the outer ring 48b of the bearing. The roller 48 is rotationally supported by the shaft 52 and 54. The blade has a length L. The amount of projection "t" may be in the range of 1/5 to 1/1000 of the roller diameter D.

As shown in Figs. 4A and 4B (where Fig. 4A is a longitudinal cross-sectional view of a roller-vane assembly unit used in the rotary machine according to another aspect of the invention, wherein the roller is supported at both ends by ball bearings, and Fig. 4B is a cross-sectional view of the unit of Fig. 4A along the line A-A of Fig. 4A), the roller may comprise a hollow cylindrical body 56 rotationally supported at the tip of the vane 58 by ball bearings 60 and 62 installed on shafts 64 and 66, respectively.

According to another aspect of the invention, as shown in Fig. 5, in the contact line 68 between the rotor 70 and stator 72 the latter can be provided with a sealing member, e.g., a seal pad 74 made from a wear resistant and low-friction material such as graphite, or a wear-resistant plastic. The pad 74 is slidingly installed in the stator 72 and is constantly biased toward the rotor 70 by a resilient member, e.g., a spring 76. When worn-out, the pad 74 can be replaced.

As shown in Fig. 6, which is a sectional view of the rotary machine made according to another aspect of the invention, in order to prevent sliding contact between the outer surface 78 of the rotor 80 and the inner surface 82 of the stator 84 in the line 86 of their mutual contact on parts of the outer surface 78 of the rotor 80 between the adjacent vanes, the pad 88 may also be provided with a roller 90 caulked on the pad's end face on the rotor side. From the side opposite to the roller 90 the pad is biased towards the rotor surface 78 by a resilient member, e.g., a spring 92. In such a construction, the rotor 80 and the stator 84 will always have a rolling contact. The pad's roller may also be made as a roller bearing or the like.

As shown in Fig. 7, which is a fragmental cross-sectional view of the rotary machine according to another aspect of the invention, the pad may be eliminated and only a spring-loaded roller 94 can be used in the line of contact of the inner surface 96 of the stator 98 with the outer surface 100 of the rotor 102.

However, although the projection of the rollers 104a, 104b, 104c, and 104d (Fig. 6) on the tips of the vanes 106a, 106b, 106c, and 106d and of the roller 90 on the end face of the seal pad 88 is very small, e.g., about 1/5 to 1/1000 of the roller diameter, a provision of the rollers 104a, 104b, 104c, and 104d on the tips of the vanes 106a, 106b, 106c, and 106d and the roller 90 on the pad 88 may cause a shock at the moment when two rollers, e.g., the roller 90 and the roller 104b, collide.

In order to solve this problem, according to one more aspect of the invention, the rotor is provided with a circumferential groove 108 (or grooves) shown in Fig. 6, which is made in such a position that allows for a small portion of the pressurized inlet fluid in the working chamber 110 between the vanes 106a and the 106b to flow under the roller 90 and the lower end face 112 of the seal pad 88 for raising the pad 88 and, hence, the roller 90, up and out of contact and anticipated collision with the approaching vane roller 104b when the letter is about to assume the position of the line of contact between the rotor 80 and the stator 84. A similar groove 102a is shown in Fig. 7 that illustrates another modification of the device.

Fig. 8 is a top view of the rotor 80 that shows positions of the grooves, three in the illustrated case, i.e., the grooves 108a, 108b, and 108c, formed on the outer surface 78 of the rotor 80 in front of the adjacent blade 106b. The length of the grooves should slightly exceed the width of the pad 88 in order to overlap the space under the roller 104 and bypass the pressurized fluid from the working chamber 110 to the space under the roller 90. Fig. 9 is a sectional view of a vane-type rotary machine 114 according to another aspect of the invention, wherein resilient means, e.g., a spring 116 is located in a sealed chamber 118. The stator 120 has a bypass channel 122 that connects the sealed chamber 118 with a low-pressure space 124 into from which the pressurized fluid is expelled through the inlet port 126 so that when the rotor 128 rotates in the counterclockwise direction, the pressure in the space 124 and, hence, in the sealed chamber 118 is reduced, whereby the seal member 130 is raised to a position away from collision with the roller 132 of the blade 134.

Fig. 10 is a sectional view of a vane-type rotary machine 136 according to another aspect of the invention, wherein the working chamber 138 of the stator 140 has an oval or elliptical shape, and the rotor 142 has two lines of contact 144 and 146 with the stator 140. The machine of this modification is similar to one shown in Fig. 9 and differs from the machine of Fig. 9 in that it is additionally provided with a second seal member 148, with a second inlet port 154 and a second outlet port 152. A second bypass channel 156 is formed in the stator 140 and connects the second sealed chamber 158 with a second space 160 from which the pressurized fluid is expelled though the second inlet port 152. As a result, when the rotor 142 rotates in the direction of the counterclockwise arrow, the pressure in the spaces 160 and 162 drops, whereby the first roller 166 and the second roller 168 are raised to positions away from collision with the rollers 170 and 172 on the vanes that approach to the first line of contact 144 and the second line of contact 146, respectively.

Thus, it has been shown that the invention provides a vane-type rotary machine with a reduced loss of power on friction and wear. The rotary machine provides rolling contact between the inner surface of the machine chamber in the stator and radial vanes. The body of rotation, such as a roller, is rotationally secured at the tip of each spring-loaded vane. The machine may have a seal pad installed in the stator. This pad may be provided with a roller, and in order to prevent collisions of the pad's roller with the rollers of the vanes, circumferential grooves are formed on the surface of the rotor ahead of the respective vanes for raising the pad's roller just prior to arrival of the vane's roller to the line of contact between the roller and stator. Although the invention has been shown and described with reference to specific embodiments, it is understood that these embodiments should not be construed as limiting the areas of application of the invention and that any changes and modifications are possible provided that these changes and modifications do not depart from the scope of the attached patent claims. For example, the body of rotation on the vanes and in the seal pad may comprise a plurality of balls. The stator chamber is not necessarily circular and may have an oval shape of the type shown in US Patent No. 3,886,764. The number of roller-raising grooves formed on the peripheral surface of the rotor may vary from one to more than three, as shown in the drawings. The number of vanes may be less than or greater than four. The rotary machine may comprise a pneumatic motor, compressor, vacuum pump, turbine, a part of a Stirling engine, etc.

Claims

1. A vane-type rotary machine with reduced wear and friction, operated by pressurized fluid, and comprising:

a stator having a machine chamber, said machine chamber having an inner surface;

a rotor rotationally installed in the stator, located inside the stator, and having an outer surface, said outer surface of the rotor having a linear contact with the inner surface of the machine chamber of the stator;

at least one radial vane slidingly installed in the rotor and having means for constantly biasing the vane to contact with the inner surface of the machine chamber of the stator, said vane having an end face on the side facing the inner surface of the machine chamber of the stator; and

a first body of rotation rotationally secured in the end face of the vane so that only a part of this first body of rotation projects from the end face, said first body of rotation having rolling contact with the inner surface of the machine chamber.

2. The vane-type rotary machine according to Claim 1 , further comprising an inlet port for supply of the pressurized fluid into a space between one side of the vane, the line of contact of the outer surface of the rotor with the inner surface of the machine chamber, and the line of contact between the first body of rotation and the inner surface of the machine chamber; and an outlet port for removing the pressurized fluid from a space between the other side of the vane, the line of contact of the outer surface of the rotor with the inner surface of the machine chamber, and the line of contact between the first body of rotation and the inner surface of the machine chamber.

3. The vane-type rotary machine according to Claim 2, further comprising: a seal member slidingly installed in the stator and having a side facing the rotor; and first resilient means constantly biasing the seal member into contact with the outer surface of the rotor, said line of contact between the outer surface of the rotor and the inner surface of the machine chamber being located on the side of the seal member facing the rotor.

4. The vane-type rotary machine according to Claim 3, further comprising a second body of rotation rotationally installed on the side of the seal member facing the rotor so that only a part of the second body of rotation projects from said side of the seal member facing the rotor.

5. The vane-type rotary machine according to any of Claims from 1 to 4, wherein the first body of rotation is a roller.

6. The vane-type rotary machine according to any of Claims from 1 to 4, wherein the first body of rotation is a roller bearing.

7. The vane-type rotary machine according to Claim 4, wherein the second body of rotation is selected from a roller and a roller bearing.

8. The vane-type rotary machine according to Claim 4, wherein the outer surface of the rotor has at least one circumferential groove located ahead of the vane in the direction of the rotation and on the side of the inlet port for supplying the pressurized fluid under the side of the seal member facing the rotor for raising the second body of rotation to a position out of contact with the first body of rotation prior to arrival of the first body of rotation to said linear contact between the outer surface of the rotor and the inner surface of the machine chamber.

9. The vane-type rotary machine according to Claim 3, wherein the seal member is a second body of rotation.

10. The vane-type rotary machine according to Claim 9, wherein the outer surface of the rotor has at least one circumferential groove located ahead of the vane in the direction of the rotation and on the side of the inlet port for supplying the pressurized fluid under the second body of rotation for raising the second body of rotation to a position out of contact with the first body of rotation prior to arrival of the first body of rotation to said linear contact between the outer surface of the rotor and the inner surface of the machine chamber.

11. A vane-type rotary machine with reduced wear and friction operated by pressurized fluid and comprising:

a plurality of radial slots in the rotor, and a plurality of vanes slidingly installed in the radial slots of the rotor and having means for constantly biasing the vanes into contact with the inner surface of the machine chamber of the stator, said vanes having an end face on the side facing the inner surface of the machine chamber of the stator; and

a first roller rotationally secured in the end face of each vane of said plurality of the vanes so that only a part of this first roller projects from the end face, said first roller having rolling contact with the inner surface of the machine chamber.

12. The vane-type rotary machine according Claim 12, wherein the first roller projects from the end face at a distance ranging from 1/5 to 1/1000 of the roller diameter.

13. The vane-type rotary machine according to Claim 12, further comprising an inlet port for supply of the pressurized fluid into a first space located on one side from line of contact between the first roller of the first vane nearest to said line of contact; and an outlet port for release of the pressurized fluid from a second space located on the other side from the line of contact between the first roller of the second vane nearest to said line of contact from said other side of the line of contact.

14. The vane-type rotary machine according to Claim 13, further comprising: a first seal member slidingly installed in the stator and having a side facing the rotor; and second resilient means constantly biasing the first seal member into contact with the outer surface of the rotor, said line of contact between the outer surface of the rotor and the inner surface of the machine chamber being located on the side of the first seal member facing the rotor.

15. The vane-type rotary machine according to Claim 14, further comprising a second roller rotationally installed on the side of the seal member facing the rotor so that only a part of the second roller projects from the side of the seal member facing the rotor.

16. The vane-type rotary machine according to any of Claims from 11 to 15, wherein the first roller is an outer ring of a roller bearing.

17. The vane-type rotary machine according to Claim 15, wherein the second roller is an outer ring of a roller bearing.

18. The vane-type rotary machine according to Claim 15, wherein the outer surface of the rotor has at least one circumferential groove located in the second space ahead of the first vane in the direction of the rotation and on the side of the inlet port for supplying the pressurized fluid under the side of the seal member facing the rotor for raising the second body of rotation to a position out of contact with the first roller prior to arrival of the first roller to said linear contact between the outer surface of the rotor and the inner surface of the machine chamber.

19. The vane-type rotary machine according to Claim 15, wherein the first seal member is a second roller.

20. The vane-type rotary machine according to Claim 19, wherein the outer surface of the rotor has at least one circumferential groove located in the second space ahead of the first vane in the direction of the rotation and on the side of the inlet port for supplying the pressurized fluid under the side of the first seal member facing the rotor for raising the second body of rotation to a position out of contact with the first roller prior to arrival of the first roller to said linear contact between the outer surface of the rotor and the inner surface of the machine chamber.

21. The vane-type rotary machine according to Claim 19, wherein the second resilient means are located in a sealed chamber, and the stator has a bypass channel that connects the sealed chamber with said second space from which the pressurized fluid is expelled so that when the rotor rotates in the direction towards the inlet port, the pressure in the second space and hence in the sealed chamber is reduced whereby the second roller is raised to a position away from collision with the first roller.

22. The vane-type rotary machine according to Claim 21, further comprising: a second seal member located diametrically opposite to the first seal member and having a second line of contact with the inner surface of the working chamber of the stator; a second inlet port and a second outlet port located on opposite sides from the second line of contact; and a second bypass channel that is formed in the stator and connects the second sealed chamber with a space from which the pressurized fluid is exhausted from the second inlet port so that when the rotor rotates in the direction toward the second inlet port, the pressure in the space on the side of the second outlet port is reduced whereby the second roller is raised to position away from collision with the roller on the vane that approaches to the second line of contact, respectively.