JP2000161270A - Rotary type fluid machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce abrasion of rollers and vanes due to sliding as the component part of a compression mechanism, and thereby actualize a rotary type fluid machine high in reliability and extremely long in life in a rotary type fluid machine and the like to be used for a refrigerator and an air conditioner. SOLUTION: This fluid machine is equipped with a mechanism for rotating a cylinder 28 and a piston 25 in the identical direction, which is provided with the cylinder 28 and the piston 25 eccentrically disposed within the cylinder 28, and with a vane 33 fitted in a vane groove 25a provided in parallel with a rotating shaft for the outer circumference of the piston 25 in such a way as to be freely put in/out while its tip end is approached to the face of the cylinder 28 so as to be formed into a suction chamber and a compression chamber. By this constitution, abrasion scarcely takes place it the tip end of the vane and the inner surface of the cylinder, it can thereby be actualized that its reliability is made high, and its life is kept long, and a high efficiency due to a decrease in sliding loss in this portion, can thereby be actually obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary fluid machine such as a compressor used for a refrigerator or an air conditioner.

[0002]

2. Description of the Related Art Rotary compressors, which are typical rotary fluid machines, are widely used in refrigerators and air conditioners because of their compactness and simple structure. The compression mechanism such as vanes and rollers, which are main components of the compressor, is described in, for example, Kawahira, Hermetic Refrigerator (1993), page 14, FIG. 6.1.

The operation of the conventional rotary compressor will be described below with reference to FIGS. 7 and 8. FIG. 7 is a longitudinal sectional view of a conventional rotary compressor, and FIG.
FIG. 3 is a cross-sectional view of an A portion (a cylinder center portion). Closed container 1
Inside, a compression mechanism comprising a crankshaft 2 having an eccentric portion, bearings 3 and 4 for supporting the crankshaft 2, a cylinder 5, a vane 6, and a roller 7 eccentrically rotating in the cylinder 5, is formed. The arc-shaped vane 6 reciprocates in the vane groove 8 of the cylinder 5, and its tip is pressed against the outer peripheral surface of the roller 7 by the spring force of the spring 9 and the force due to the pressure difference between the inside and outside of the cylinder 5. Roller 7
The cylinder 5 is divided into a suction chamber 10 and a discharge chamber 11 by sliding in contact with the outer peripheral portion of the cylinder 5.

[0004] O is the center of the cylinder 5 and the crankshaft 2,
The crankshaft 2 has an eccentric portion (hereinafter referred to as a crankpin) 12 centered on P which is eccentric from the center O by e, and a roller 7 is fitted to the crankpin 12.

[0005] When the crankshaft 2 is rotated by the electric motor including the stator 13 and the rotor 14 and the roller 7 revolves in the cylinder 5, the refrigerant gas is supplied to the suction port 1.
5 and is sent to the discharge port 16 while being compressed.
The refrigerant gas at the discharge port 16 is compressed by being sent to the refrigeration cycle side through the discharge valve 17.

There is another type called a sliding vane type rotary compressor (not shown), in which a vane provided in a cylinder in a vane groove provided on a rotary piston so as to freely move in and out together with the piston. Some rotate to perform a compression action.

[0007]

However, in the above-described conventional configuration, the tip of the vane 6 has an arcuate curved surface,
Since the outer peripheral surface of the roller 7 is also a circular curved surface (cylindrical surface),
The contact state between the vane 6 and the roller 7 is equivalently a contact between the convex surfaces of the small cylinder and the large cylinder. Therefore, the contact state is a line contact state, the contact area is small, the load per unit area, that is, the contact stress is large, the contact sliding condition between the vane 6 and the roller 7 is severe, abrasion is liable to occur, and the sliding is easy. The dynamic loss also increases.

The number of rotations of the roller 7 is also determined by the difference in sliding resistance between the inner peripheral surface of the roller 7 and the crankpin 12 and the sliding resistance between the outer peripheral surface of the roller 7 and the tip of the vane 6. The rotation speed of the roller 7 is very unstable (generally, when the rotation speed of the crankshaft 2 is 3600 rpm, the rotation speed of the roller is several tens to several hundreds rpm). For this reason, the sliding speed of the leading end of the vane 6 and the sliding surface of the roller 7 varies depending on the conditions, resulting in unstable sliding.

Further, when an alternative refrigerant containing no chlorine, such as HFC134a, is used, the lubricating effect of the refrigerant itself is poor, and there is a problem that the lubricating property is remarkably reduced when the oil film of the sliding portion is broken. In the case of the compressor, there is a problem that abrasion easily occurs between the outer periphery of the roller 7 where the oil film is not easily formed and the tip of the vane 6, and the life is remarkably shortened.

In the case of a sliding vane type rotary compressor, the convex arc vane slides on the cylinder inner surface of the concave arc, and the contact shape is more advantageous than that described above. Since the sliding speed at the tip increases in proportion to the number of rotations and the inner diameter of the cylinder, extremely severe sliding conditions are required, and it is not suitable for refrigerators and air conditioners that require a long life.

In view of the above-mentioned problems of the conventional rotary fluid machine, the present invention reduces the load on the sliding portion at the tip of the vane, increases the reliability and extends the life, and reduces the sliding loss. It is an object of the present invention to provide a rotary fluid machine with improved efficiency.

[0012]

Means for Solving the Problems The first invention (claim 1)
A) a shaft rotatable around a first rotation axis, a cylindrical piston attached to the shaft and having the first rotation axis as a central axis, and a first bearing member supporting the shaft. The second rotating shaft eccentric by a predetermined eccentric width with respect to the first rotating shaft is the central axis of the cylindrical hollow portion,
And a cylinder rotatable around the second rotation axis, a partition plate provided at one end of the cylinder, and a vane groove provided on an outer peripheral surface of the piston in parallel with the first rotation axis, A vane inserted and inserted into and out of the vane groove, and a driving element for rotating the piston; a thickness of the piston in the first rotation axis direction and a thickness of the hollow portion of the cylinder in the second rotation axis direction. The thickness is substantially the same, the cylinder is in contact with the first bearing member via a sliding surface, and the predetermined eccentric width is set such that the outer peripheral surface of the piston and the inner surface of the cylinder are close to each other. The space formed by the hollow part of the cylinder and the piston is divided into a suction chamber and a discharge chamber by the tip of the vane being close to the inner surface of the hollow part of the cylinder, and the partition plate Cylindrical zag Parts are provided, on the inside of the counterbore portion, said piston and said cylinder is a rotary fluid machine, wherein the cylindrical Oldham joint having a function of rotating in the same direction are provided.

According to a second aspect of the present invention (corresponding to claim 5), there is provided a shaft rotatable around a first rotation axis, and a cylindrical piston attached to the shaft and having the first rotation axis as a center axis. And a first bearing member that supports the shaft,
A second rotation axis eccentric by a predetermined eccentric width with respect to the first rotation axis is the center axis of the cylindrical hollow portion, and a cylinder rotatable around the second rotation axis, and one end of the cylinder. A provided partition plate, a vane groove provided on the outer peripheral surface of the piston in parallel with the first rotation axis, a vane inserted and inserted into and out of the vane groove, and a driving element for rotating the piston. An internal gear provided on the partition plate and rotatable about the second rotation axis, and an external gear rotatable about the first rotation axis and meshing with the internal gear, wherein the first of the pistons The thickness in the rotation axis direction and the thickness in the second rotation axis direction of the hollow portion of the cylinder substantially match, the cylinder is in contact with the first bearing member via a sliding surface, and the predetermined eccentric width is , The outer peripheral surface of the piston and the cylinder And a space defined by the hollow portion of the cylinder and the piston. The space formed by the hollow portion of the cylinder and the piston is close to the inner surface of the hollow portion of the cylinder. Divided into rooms
The internal gear and the external gear serve to rotate the piston and the cylinder in the same direction.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. (Embodiment 1) FIG. 1 is a longitudinal sectional view of a rotary type fluid machine according to a first embodiment of the present invention, and FIG. 2 is a transverse sectional view of a BB portion (cylinder central portion) thereof. FIG. 3 is a perspective view of the components. The rotary fluid machine according to the present embodiment is a rotary fluid machine used as a compressor of a refrigeration cycle apparatus using a fluid containing no chlorine such as HFC134a as a working medium.

An electric element including a rotor 22 and a stator 23 is provided in the sealed shell 21. The shaft 24 and the rotor 22 are integrated so that the rotation axis L1 is coincident, and a cylindrical piston 25 centered on the rotation axis L1 is provided. The shaft 24 is fitted with a through hole of a piston 25 and the shaft 24 and is fixed by a parallel key 26. Shaft 24
Is rotatably supported by a first bearing member 27, and a cylinder 28 having a rotation axis L2 eccentric with respect to the rotation axis L1 by a predetermined eccentric width e and having a central axis of the cylindrical hollow portion is provided at one end thereof. A partition plate 29 and a cylinder shaft 30 coinciding with the rotation axis L2 are provided.
1 rotatably supported. Here, the predetermined eccentric width e is a width set so that the inner circumference of the cylinder 28 and the outer circumference of the piston 25 are close to each other.

The partition plate 29 is provided with a counterbore portion 29a having the rotation axis L2 as the center axis of the cylindrical hollow portion.
A concave key 29b is provided on the bottom surface of 9a, and a convex key 24a is provided at the tip of the shaft 24. Inside the counterbore portion 29a, a cylindrical Oldham coupling 32 is provided.
A concave key 32a that fits with the convex key 24a at the tip, and a convex key 3 that fits with the concave key 29b of the partition plate 29 on the lower end surface.
2b is provided. Oldham shaft coupling 32 is made of tool steel, and is quenched and tempered to reduce the surface hardness to Hr.
Set to c45 or more. Further, in order for the Oldham coupling 34 to function as a coupling, it is necessary to perform a reciprocating motion of a distance twice the eccentric width e on the concave key 29b on the bottom surface of the counterbore portion 29a. In addition, the radius r _z of the counterbore portion 29a is configured to satisfy the condition represented by r _o + e ≦ r _z using the radius r _o of the Oldham shaft coupling 32 and a predetermined eccentric width e. Further, the depth hz of the counterbore portion 29a is configured to substantially match the thickness ho of the Oldham shaft coupling 32.

On the outer periphery of the piston 25, there are provided a vane groove 25a provided in parallel with the rotation axis L1 and a vane 33 which is inserted in the vane groove 25a so as to be able to freely enter and exit, and whose tip is close to the inner surface of the cylinder 28. . Vane 33 is piston 2
The space between the cylinder 5 and the cylinder 28 is divided to form a suction chamber 34 and a discharge chamber 35.

The upper end surface of the piston 25 has a first bearing member 27
And the lower end surface of the piston 25 is arranged closely to the upper end surface of the partition plate 29. Furthermore, the upper end surface of the cylinder 28 is arranged in close contact with the lower end surface of the first bearing member 27 to prevent fluid leakage.

The radius r _z of the counterbore portion 29a is set so that the counterbore portion 29a is covered by the lower end surface of the piston 25.
Using a radius r _{p of the} piston 25 and a predetermined eccentric width e, r _z ≦
and satisfies structure represented by r _p -e, counterbore portion 2
The structure prevents leakage of fluid between the suction chamber 9a and the suction chamber 34 and the discharge chamber 35.

The first bearing member 27 is provided with a suction port 27a and a discharge port 27b. The suction chamber 34 communicates with the suction pipe 36 via the suction port 27a, and the discharge chamber 35
Is the discharge pipe 3 through the discharge port 27b and the closed shell 21.
It communicates with 7.

The operation of the rotary fluid machine according to the present embodiment will be described below with reference to FIGS.

By operating an electric element including the rotor 22 and the stator 23, the shaft 24 is driven, and the piston 25 integrated therewith is rotated. In addition, the partition plate 29 having the concave key 29b which fits with the Oldham shaft coupling 32 and the cylinder 28 integral with the Oldham shaft coupling 32 by the Oldham shaft coupling 32 which fits with the convex key 24a at the tip of the shaft 24 in the same direction as the piston 25. Rotate synchronously.
At this time, the vane 33 rotates around the rotation axis L1 together with the piston 25 while moving in and out of the vane groove 25a provided in the piston 25 so as to approach the inner surface of the cylinder 28 by centrifugal force and back pressure.

As a result, the volume of the discharge chamber 35 formed on the side in the direction of rotation of the vane 33 decreases with the rotation, and the volume of the suction chamber 34 formed on the side opposite to the direction of rotation increases. become. Therefore, during the refrigeration cycle,
The fluid (for example, HFC 134a) sucked from the suction port 27a through the suction pipe 36 is compressed, discharged once into the closed shell 21 through the discharge port 27b, and returned to the refrigeration cycle from the discharge pipe 37. It is.

In this embodiment, since the Oldham shaft coupling 32 is used, the piston 25 and the cylinder 28 can be synchronously rotated in the same direction. Therefore, the vane 33
Between the tip of the cylinder and the inner surface of the cylinder 28 is a convex arc on the vane 32 side and a concave arc on the cylinder 28 side, which is a shape suitable for forming an oil film, and is equivalent to twice the eccentric width e per rotation. Stable reciprocating sliding is performed, regardless of the inner diameter of the cylinder 28, and the sliding speed is much lower than that of the conventional sliding vane type rotary compressor. Therefore, HFC134, which has poor lubricity in the fluid itself,
Also, when a is used as the working medium, the tip of the vane 33 and the inner surface of the cylinder 28 are hardly worn, and high reliability and long life can be realized, and sliding loss of this portion can be reduced. Efficiency can be improved.

Also, tool steel is used as the material of the Oldham shaft coupling 32, and quenching and tempering are performed to reduce the surface hardness to Hrc45.
As described above, the Oldham shaft coupling 32 that is compact and has sufficient strength and wear resistance can be configured.

Since the Oldham shaft coupling 32 is provided inside the counterbore portion 29a of the partition plate 29, a very compact rotary fluid machine can be provided.

Further, since the counterbore portion 29a serves as an oil reservoir, oil is supplied to a sliding surface between the Oldham shaft coupling 32 and the convex key 24a at the tip of the shaft 24 and the concave key 29b of the counterbore portion 29a. High efficiency can be achieved by reducing the loss.

Further, a convex key 24a is provided at the tip of the shaft 24.
Is provided, the torque for driving the cylinder 28 is transmitted from the rotor 22 to the cylinder 28 only through the shaft 24 and the Oldham coupling 32, and the piston 2
Do not go through 5. Therefore, the transmission path of the torque is very simple, the play around the rotation axis L2 of the cylinder 28 due to the clearance between the parts can be reduced, and the vibration and noise can be reduced. Is deformed and the vane 33 and the vane groove 25 are deformed.
The occurrence of seizure due to the narrow clearance of a,
An increase in fluid leakage due to an increase in the clearance between the vane 33 and the vane groove 25a can be prevented, and reliability can be improved and efficiency can be improved. (Embodiment 2) FIG. 4 is a partial longitudinal sectional view of a rotary fluid machine according to a second embodiment of the present invention. The configuration of the rotary fluid machine of the present embodiment is the same as that of the first embodiment shown in FIGS. 1 to 3 except for the shapes of the shaft and the piston. Therefore, in the present embodiment, a description of a portion having the same function as in the first embodiment will be omitted.

In this embodiment, the cylindrical piston 41 and the shaft 42 centered on the rotation axis L1
The first non-through hole is fitted to the shaft 42, and the parallel key 43
And a convex key 41 a is provided on the lower end surface of the piston 41.

With such a configuration, the length of the convex key 41a on the lower end surface of the piston 41 fitted to the concave key 44a on the upper end surface of the Oldham shaft coupling
Can be extended regardless of the diameter of the cylinder 4
Even when the diameter of 5 is large and a large torque is required to rotationally drive the cylinder 45, the convex key 41a can maintain a sufficient strength, and the reliability can be improved.

The predetermined eccentric width e is large and the piston 4
(1) Even when the amount of movement of the Oldham shaft coupling 44 on the convex key 41a on the lower end surface is large, the engagement between the Oldham shaft coupling 44 and the convex key 44a on the lower end surface of the piston 41 can be sufficiently maintained, and Since the movement of the shaft coupling 44 becomes smooth and wear is reduced, reliability is improved. (Embodiment 3) FIG. 5 is a perspective view of components of a rotary fluid machine according to a third embodiment of the present invention. The configuration of the rotary fluid machine of the present embodiment is the same as that of FIG.
This is similar to the first embodiment shown in FIGS. Therefore, in the present embodiment, a description of a portion having the same function as in the first embodiment will be omitted.

In this embodiment, a counterbore portion 51a is provided on the partition plate 51, and an internal gear 51b having a rotation axis L2 as a central axis is provided on the inner surface of the counterbore portion 51a. Is provided with an external gear 52a having the rotation axis L1 as a central axis. At this time, the difference between the radii of the respective pitch circles of the internal gear 51b and the external gear 52a is made equal to the predetermined eccentric width e so that they mesh with each other. Also,
The radius r of the root circle of the internal gear 51b is set so that the internal gear 51b of the counterbore portion 51a is covered by the lower end surface of the piston 53.
_g is calculated using a radius r _p of the piston 53 and a predetermined eccentric width e.
and satisfies structure represented by r _g ≦ r _p -e, are configured to prevent leakage of fluid between the counterbore portion 51a and the suction chamber (not shown) and a discharge chamber (not shown).

The operation of the rotary fluid machine according to the present embodiment is as follows. By operating an electric element including a rotor (not shown) and a stator (not shown), the shaft 52 is driven, and a piston 5 integrated therewith is driven.
3 rotates. Also, an external gear 52 at the tip of the shaft 52
Due to the internal gear 51b of the partition plate 51 meshing with a, the partition plate 51 and the cylinder 54 integrated therewith rotate in the same direction as the piston 53.

In the present embodiment, the internal gear 5
1b is provided with an external gear 52a at the tip of the shaft 52 so as to mesh with each other.
4 can be rotated in the same direction. Therefore,
The sliding between the tip of the vane 55 and the inner surface of the cylinder 54 is a convex arc on the vane 55 side and a concave arc on the cylinder 54 side.
The shape is suitable for forming an oil film, and the sliding speed between the tip of the vane 55 and the inner surface of the cylinder 54 is much slower than that of a conventional sliding vane type rotary compressor. Therefore, HFC1 with poor lubricity in the fluid itself
34a as the working medium, the vane 5
5 and the inner surface of the cylinder 54 are hardly worn, so that a high reliability and a long service life can be realized, and a sliding loss of this portion can be reduced to improve efficiency.

An internal gear 51b is provided on the inner surface of the counterbore portion 51a of the partition plate 51, and the external gear 5 at the tip of the shaft 52 is provided.
Since the 2a is located inside the counterbore portion 51a of the partition plate 51, a very compact rotary fluid machine can be provided.

Further, since the counterbore portion 51a serves as an oil reservoir, oil is supplied between the internal gear 51b and the external gear 52a meshing on the inner surface of the counterbore portion 51a, thereby achieving high efficiency by reducing sliding loss. Can be.

Further, an external gear 52 is attached to the tip of the shaft 52.
By providing a, the torque for driving the cylinder 54 is transmitted from the rotor (not shown) to the cylinder 54 only through the shaft 52 and not through the piston 53. Therefore, the transmission path of the torque is very simple, the play around the rotation axis L2 of the cylinder 54 due to the clearance between the parts can be reduced, the vibration and the noise can be reduced, and the torque of the piston 53 can be reduced. Can be prevented and seizure due to narrowing of the clearance between the vane 55 and the vane groove 53a and increase in fluid leakage due to widening of the clearance between the vane 55 and the vane groove 53a can be prevented, thereby improving reliability and increasing efficiency. Can be achieved. (Embodiment 4) FIG. 6 is a partial longitudinal sectional view of a rotary fluid machine according to a fourth embodiment of the present invention. The configuration of the rotary fluid machine of the present embodiment is the same as that of the third embodiment shown in FIG. 5 except for the shapes of the shaft and the piston. Therefore, in the present embodiment, a description of a portion having the same function as in the third embodiment will be omitted.

In this embodiment, the cylindrical piston 61 and the shaft 62 centered on the rotation axis L1
The parallel key 63 is fitted with the non-through hole 1 and the shaft 62.
The external gear 61 a is provided on the lower end surface of the piston 61 so as to mesh with the internal gear 64 a of the partition plate 64.

With such a configuration, the internal gear 64a of the partition plate 64 and the piston 61 meshing therewith are provided.
The diameter of the external gear 61a on the lower end surface of the shaft 65 can be increased irrespective of the diameter of the shaft 62. Therefore, even when the diameter of the cylinder 65 is large and a large torque is required to rotationally drive the cylinder 65, the internal gear 64a And external gear 61
a can maintain sufficient strength and can improve reliability.

In the first to fourth embodiments, the working medium handled in the rotary fluid machine of the present invention has been described as a refrigerant containing no chlorine, such as HFC134a, but is limited to this. Not something.

[0041]

As is apparent from the above description, in the present invention, the sliding between the vane tip and the inner surface of the cylinder has a convex arc on the vane side and a convex arc on the cylinder side, and has a shape suitable for oil film formation. In addition, the sliding speed between the vane tip and the inner surface of the cylinder is much lower than that of a conventional sliding vane type rotary compressor. Therefore, even when HFC134a or the like, which has poor lubricity, is used as the working medium, the tip of the vane and the inner surface of the cylinder are hardly abraded, and high reliability and long life can be achieved. The loss can also be reduced and higher efficiency can be achieved.

Further, since a mechanism for rotating the piston and the cylinder in the same direction is provided inside the counterbore portion of the partition plate of the cylinder, a very compact rotary fluid machine can be provided.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a rotary fluid machine according to Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view taken along a line BB in FIG. 1;

FIG. 3 is a perspective view of components of the rotary fluid machine according to Embodiment 1 of the present invention.

FIG. 4 is a partial longitudinal sectional view of a rotary fluid machine according to Embodiment 2 of the present invention.

FIG. 5 is a perspective view of components of a rotary fluid machine according to Embodiment 3 of the present invention.

FIG. 6 is a partial longitudinal sectional view of a rotary fluid machine according to Embodiment 4 of the present invention.

FIG. 7 is a longitudinal sectional view of a conventional rotary compressor.

8 is a cross-sectional view taken along the line AA in FIG. 7;

[Explanation of symbols]

 24, 42, 52, 62 Shaft 25, 41, 53, 61 Piston 28, 45, 54, 65 Cylinder 32, 44 Oldham coupling 33, 55 Vane 51b, 64a Internal gear 52a, 61a External gear

Continued on the front page (72) Inventor Fumitoshi Nishiwaki 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Hidenobu 1006 Kadoma Kadoma, Osaka Pref. 3H029 AA05 AB03 BB01 BB16 BB42 BB44 CC03 CC05 CC08 CC19 3H040 AA09 BB01 BB10 BB11 CC05 CC09 CC14 DD02 DD07 DD09 DD32

Claims (9)

[Claims] A shaft rotatable around a first rotation axis, a cylindrical piston attached to the shaft and having the first rotation axis as a center axis, and a first bearing member supporting the shaft. The second rotating shaft eccentric by a predetermined eccentric width with respect to the first rotating shaft is the central axis of the cylindrical hollow portion,
And a cylinder rotatable around the second rotation axis, a partition plate provided at one end of the cylinder, and a vane groove provided on an outer peripheral surface of the piston in parallel with the first rotation axis, A vane inserted and inserted into and out of the vane groove, and a driving element for rotating the piston; and a thickness of the piston in the first rotation axis direction and a thickness of the hollow portion of the cylinder in the second rotation axis direction. The thickness is substantially the same, the cylinder is in contact with the first bearing member via a sliding surface, and the predetermined eccentric width is set such that the outer peripheral surface of the piston and the inner surface of the cylinder are close to each other. The space formed by the hollow part of the cylinder and the piston is divided into a suction chamber and a discharge chamber by the tip of the vane being close to the inner surface of the hollow part of the cylinder, and the partition plate Cylindrical zag A rotary fluid machine, comprising: a rear portion; and a cylindrical Oldham shaft coupling having a function of rotating the piston and the cylinder in the same direction inside the counterbore portion. 2. A radius r _z of the counterbore portion, the radius r _o of the Oldham joint, the radius r _p of the piston, and the predetermined eccentricity width e satisfies the _{r o + e ≦ r z ≦} r p -e The rotary fluid machine according to claim 1, wherein: 3. The rotary fluid machine according to claim 1, wherein a key that fits with the Oldham shaft coupling is provided at a tip of the shaft. 4. The rotary fluid machine according to claim 1, wherein a key that fits with the Oldham shaft coupling is provided on an end surface of the piston. 5. A shaft rotatable around a first rotation axis, a cylindrical piston attached to the shaft and having the first rotation axis as a center axis, and a first bearing member supporting the shaft. The second rotating shaft eccentric by a predetermined eccentric width with respect to the first rotating shaft is the central axis of the cylindrical hollow portion,
And a cylinder rotatable around the second rotation axis, a partition plate provided at one end of the cylinder, and a vane groove provided on an outer peripheral surface of the piston in parallel with the first rotation axis, A vane inserted and inserted into and out of the vane groove, a driving element for rotating the piston, an internal gear provided on the partition plate and rotatable around the second rotation axis, and a first rotation shaft; An external gear rotatable around and meshing with the internal gear, wherein the thickness of the piston in the first rotation axis direction and the thickness of the hollow portion of the cylinder in the second rotation axis direction substantially match, Is in contact with the first bearing member via a sliding surface, the predetermined eccentric width is a width set so that the outer peripheral surface of the piston and the inner surface of the cylinder are close to each other, and the hollow of the cylinder Part and the piston The space formed is divided into a suction chamber and a discharge chamber by the tip of the vane approaching the inner surface of the hollow portion of the cylinder, and the internal gear and the external gear rotate the piston and the cylinder in the same direction. A rotary fluid machine characterized by the function of causing a fluid to flow. 6. The radius r _g of the root circle of the internal gear, the radius r _{p of} the piston, and the predetermined eccentric width e are r _g ≦ r _p −e.
The rotary fluid machine according to claim 5, wherein the following is satisfied. 7. The rotary fluid machine according to claim 5, wherein the external gear is provided at a tip of the shaft. 8. The rotary fluid machine according to claim 5, wherein the external gear is provided on an end face of the piston. 9. The rotary fluid machine according to claim 1, wherein the rotary fluid machine is operated using a refrigerant containing no chlorine as a working medium.