Scroll-type fluid machinery

Abstract

To suppress inclination of an axis of an eccentric bush with respect to an axis of a drive shaft in a scroll-type fluid machine.SOLUTION: Planar engagement parts 218D, 224C are respectively formed in a part of an outer peripheral surface of a drive shaft 218, which transmits rotational driving force to revolve an orbiting scroll via a pivot member, and in a part of an inner peripheral surface of a cylindrical part 224A of an eccentric bush 224, which is supported so as to be at least partially displaceable in a circumferential direction with respect to an inner peripheral surface of the pivot member, and which has an inner diameter larger than a diameter of the drive shaft 218, the planar engagement parts providing guides that receive compressive reaction force of the orbiting scroll to move the orbiting scroll in an orbiting radius direction. Further, a pin 228 is provided, which extends through the eccentric bush 224 and the drive shaft 218 in parallel with the planar engagement parts 218D, 224C to restrict inclination of an axis of the eccentric bush 224 with respect to an axis of the drive shaft 218.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to a scroll-type fluid machine that compresses or expands a fluid by changing the volume of a compression chamber defined by a fixed scroll and an orbiting scroll. [Background technology]

[0002] As described in Japanese Patent Laid-Open No. 2008-240597 (Patent Document 1), a scroll-type fluid machine is provided with a mechanism that automatically adjusts the orbital radius of the orbiting scroll using the compression reaction force of the scroll unit so that the wraps come into contact with each other when the orbiting scroll orbits. In the mechanism that automatically adjusts the orbital radius of the orbiting scroll, a flat engagement portion is formed at a location where an eccentric bushing integrated with a balance weight engages with a drive shaft that transmits rotational driving force, allowing the eccentric bushing to move outward from the orbital radius relative to the drive shaft. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-240597 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology described in Patent Document 1, the drive shaft and the eccentric bushing are capable of relative displacement, leaving a small gap between them. As a result, rotation of the balance weight causes the axis of the eccentric bushing to tilt relative to the axis of the drive shaft, which can cause the balance weight to come into contact with surrounding components, potentially resulting in sliding resistance or abnormal noise, for example.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to suppress the inclination of the axis of an eccentric bush relative to the axis of a drive shaft in a scroll-type fluid machine. [Means for solving the problem]

[0006] The scroll-type fluid machine includes a fixed scroll, an orbiting scroll meshed with the fixed scroll, a disk-shaped swinging member integrated with and concentric with the orbiting scroll, a drive shaft transmitting a rotational driving force for revolving the orbiting scroll via the swinging member, and an eccentric bushing having a cylindrical portion supported at least partially on the inner peripheral surface of the swinging member so as to be displaceable in the circumferential direction and having an inner diameter larger than that of the drive shaft, and a balance weight portion integrated with the cylindrical portion. The outer peripheral surface of the drive shaft and a portion of the inner peripheral surface of the cylindrical portion are each formed with flat engaging portions that serve as guides for receiving a compressive reaction force from the orbiting scroll and moving the orbiting scroll in the orbiting radius direction. A pin is provided that extends parallel to the flat engaging portions and penetrates the eccentric bushing and the drive shaft, restricting the inclination of the axis of the eccentric bushing relative to the axis of the drive shaft. [Effects of the Invention]

[0007] According to the present invention, in a scroll-type fluid machine, it is possible to suppress the inclination of the axis of the eccentric bush with respect to the axis of the drive shaft. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a scroll compressor. [Figure 2] FIG. 2 is a plan view showing an example of a rear gasket. [Figure 3] FIG. 2 is a partial cross-sectional view showing an example of a rear gasket. [Figure 4] FIG. 2 is a plan view showing an example of a fixed scroll. [Figure 5] FIG. 2 is a perspective view showing an example of a fixed scroll. [Figure 6] FIG. 2 is a plan view showing an example of a thrust plate. [Figure 7] FIG. 2 is a rear view showing an example of a fixed scroll. [Figure 8] FIG. 4 is a plan view showing the relationship between the fixed scroll and the rear gasket. [Figure 9] FIG. 4 is an explanatory diagram of a configuration for ensuring a seal between the orbiting scroll and the thrust plate. [Figure 10] FIG. 2 is a plan view showing an example of a metal member. [Figure 11] 10 is a cross-sectional view of a main part of a configuration for restricting the inclination of an eccentric bushing relative to a drive shaft. FIG. [Figure 12] FIG. 10 is a cross-sectional view showing an example of a pin. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Although either a compressor or an expander can be used as the scroll-type fluid machine, the present specification will be described as a scroll-type compressor.

[0010] FIG. 1 shows an example of a scroll compressor 100 . The scroll compressor 100 is incorporated, for example, in a refrigerant circuit of a vehicle air conditioner (not shown), draws in and compresses low-pressure gas refrigerant (compressible fluid) from the refrigerant circuit, and discharges high-pressure gas refrigerant into the refrigerant circuit. The scroll compressor 100 includes a scroll unit 120, a housing 140 containing a suction chamber H1 and a discharge chamber H2 for the gas refrigerant, and an electric motor 160 that drives the scroll unit 120. The scroll unit 120 may be driven by, for example, engine output instead of the electric motor 160. The scroll compressor 100 may further include an inverter that drives and controls the electric motor 160.

[0011] The scroll unit 120 has a fixed scroll 122 and an orbiting scroll 124 that are combined with each other. The fixed scroll 122 has a disk-shaped bottom plate 122A and an involute-shaped (spiral-shaped) wrap 122B that stands upright from one surface of the bottom plate 122A. Like the fixed scroll 122, the orbiting scroll 124 has a disk-shaped bottom plate 124A and an involute-shaped wrap 124B that stands upright from one surface of the bottom plate 124A. Here, the disk shape may be such that it can be recognized as a disk shape by appearance, and for example, convex portions, concave portions, slits, etc. may be formed on the outer surface (the same applies to shapes below).

[0012] The fixed scroll 122 and the orbiting scroll 124 are arranged with the wraps 122B and 124B meshed with each other. Therefore, the tip end of the wrap 122B of the fixed scroll 122 is in slidable contact with one surface of the bottom plate 124A of the orbiting scroll 124. On the other hand, the tip end of the wrap 124B of the orbiting scroll 124 is in slidable contact with one surface of the bottom plate 122A of the fixed scroll 122. Tip seals (not shown) may be attached to the tip ends of the wraps 122B and 124B, respectively.

[0013] The fixed scroll 122 and the orbiting scroll 124 are arranged such that the wraps 122B and 124B are offset from each other in the circumferential direction and the side walls of the wraps 122B and 124B are in partial contact with each other. Therefore, a crescent-shaped sealed space is formed between the fixed scroll 122 and the orbiting scroll 124, which functions as a compression chamber H3 that compresses the gaseous refrigerant.

[0014] The orbiting scroll 124 is arranged to revolve around the axis of the fixed scroll 122 while being prevented from rotating. When the orbiting scroll 124 revolves around the axis of the fixed scroll 122, the scroll unit 120 moves the crescent-shaped compression chamber H3 toward the center while gradually reducing the volume of the compression chamber H3. As a result, the scroll unit 120 draws gaseous refrigerant from near the outer ends of the wrap 122B of the fixed scroll 122 and the wrap 124B of the orbiting scroll 124 into the compression chamber H3 and compresses it.

[0015] The housing 140 has a motor housing 142 that mainly houses the electric motor 160, a rear housing 144 that mainly houses the scroll unit 120, and a center gasket 146 that is arranged between the motor housing 142 and the rear housing 144. The housing 140 of the scroll compressor 100 is configured by the motor housing 142 and the rear housing 144 being separably fastened together with the center gasket 146 interposed therebetween by, for example, fasteners (not shown) including bolts.

[0016] The motor housing 142 is formed in a cylindrical shape with a bottom, having a cylindrical peripheral wall portion 142A and a disk-shaped bottom wall portion 142B that closes one axial end face of the peripheral wall portion 142A. A cylindrical support portion 142B1 is formed in the center of the bottom wall portion 142B to rotatably support one end of a drive shaft 218 (described later). The support portion 142B1 extends from the bottom wall portion 142B toward the other end of the peripheral wall portion 142A.

[0017] Additionally, a suction port P1 is formed in a predetermined location on the peripheral wall 142A of the motor housing 142 adjacent to the bottom wall 142B thereof, through which low-pressure gaseous refrigerant is drawn from the refrigerant circuit. Therefore, the interior space of the motor housing 142 functions as a suction chamber H1 that draws in the gaseous refrigerant through the suction port P1. In the suction chamber H1, the gaseous refrigerant flows around the electric motor 160 to cool the electric motor 160, and two spaces located on both axially outer sides of the electric motor 160 communicate with each other to form a single suction chamber H1. An appropriate amount of lubricating oil is stored in the suction chamber H1 to lubricate sliding parts such as the drive shaft 218 that rotates. Therefore, the gaseous refrigerant flows through the suction chamber H1 in a state mixed with the lubricating oil.

[0018] The rear housing 144 is formed in a cylindrical shape with a bottom, and includes a stepped cylindrical peripheral wall 144A consisting of a large-diameter portion and a small-diameter portion whose diameter changes in two stages, and a disk-shaped bottom wall 144B that closes the opening of the small-diameter portion of the peripheral wall 144A. The scroll unit 120 is accommodated in the internal space of the rear housing 144. Specifically, the peripheral edge of the bottom plate 122A of the fixed scroll 122 is fitted and fixed to the innermost portion of the large-diameter portion of the peripheral wall 144A, with an annular rear gasket 200 interposed between the stepped portion 144A1 consisting of an annular flat surface that transitions from the large-diameter portion to the small-diameter portion. Therefore, the innermost portion of the large-diameter portion of the rear housing 144 is closed by the fixed scroll 122. Furthermore, a discharge hole 122C is formed in the center of the bottom plate 122A of the fixed scroll 122, through which the high-pressure gaseous refrigerant compressed by the scroll unit 120 is discharged to the small diameter portion of the rear housing 144. A discharge valve 202, for example a one-way valve, is attached to the other surface of the bottom plate 122A of the fixed scroll 122, which discharges the compressed high-pressure gaseous refrigerant from the compression chamber H3 to the small diameter portion while preventing the high-pressure gaseous refrigerant from flowing back from the small diameter portion to the compression chamber H3.

[0019] A partition wall portion 144C extending on an inclined surface from the bottom surface of the bottom wall portion 144B toward the other surface of the fixed scroll 122 is formed in a predetermined location on the bottom wall portion 144B of the rear housing 144 that is located below the discharge hole 122C of the fixed scroll 122. Here, as shown in Fig. 2, the rear gasket 200 is formed with a linear portion 200A that extends linearly at a position corresponding to the formation position of the partition wall portion 144C in order to seal between the tip end of the partition wall portion 144C and the other surface of the bottom plate 122A of the fixed scroll 122. In addition, as shown in Fig. 3, the rear gasket 200 is formed with a protruding portion 200B that protrudes from the center of the outer periphery of the annular shape.

[0020] Therefore, the small diameter portion of the rear housing 144 is divided into two spaces: an upper space defined by the upper surfaces of the bottom plate 122A, circumferential wall 144A, bottom wall 144B, and partition 144C of the fixed scroll 122, and a lower space defined by the lower surfaces of the bottom plate 122A, circumferential wall 144A, bottom wall 144B, and partition 144C of the fixed scroll 122. A centrifugal oil separator 204, for example, is attached to the upper space located at the innermost portion of the rear housing 144, to separate lubricating oil from the high-pressure gaseous refrigerant compressed by the scroll unit 120. Therefore, an oil passage 144C1 is formed in a predetermined position of the partition 144C of the rear housing 144, for supplying the lubricating oil separated by the oil separator 204 to the lower space, which functions as the lubricating oil reservoir chamber H4. Additionally, the upper space facing the fixed scroll 122 functions as a discharge chamber H2 that temporarily stores the high-pressure gaseous refrigerant discharged from the discharge hole 122C of the fixed scroll 122. Furthermore, a discharge port P2 is formed in a predetermined location on the peripheral wall 144A of the rear housing 144 that is located above the oil separator 204. The discharge port P2 discharges the high-pressure gaseous refrigerant, from which the lubricating oil has been separated by the oil separator 204, into the refrigerant circuit.

[0021] A stepped portion 142C consisting of a circular flat surface where the inner diameter of the peripheral wall portion 142A increases is formed near the open end of the peripheral wall portion 142A of the motor housing 142. A thrust plate 206 is disposed on the stepped portion 142C and receives the thrust force of the orbiting scroll 124 during compression of the gaseous refrigerant by the scroll unit 120. The thrust plate 206 has a circular disk portion 206A whose one surface of the periphery abuts against the stepped portion 142C of the motor housing 142, and a cylindrical protrusion 206B of a predetermined length that extends from the center of one surface of the disk portion 206A toward the bottom wall portion 142B of the motor housing 142.

[0022] 4 and 5, the bottom plate 122A of the fixed scroll 122 is formed with a plurality of arc-shaped protrusions 122D extending from the outer circumferential edge of one surface thereof to the thrust plate 206 in order to urge the thrust plate 206 toward the stepped portion 142C of the motor housing 142 by utilizing the elasticity of the rear gasket 200. The protrusions 122D are formed, for example, at three locations that divide the outer circumferential edge of the bottom plate 122A into three equally spaced sections, and over a predetermined length such that adjacent protrusions 122D are not adjacent to each other. Furthermore, pin holes 122D1 are formed in the tip surfaces of the two protrusions 122D, respectively, into which the ends of positioning pins 208 (see FIG. 1) that position the thrust plate 206 relative to the fixed scroll 122 are fitted. For this reason, the disk portion 206A of the thrust plate 206 is formed with a pin hole 206C in which the positioning pin 208 fits at a position corresponding to the pin hole 122D1 of the protruding portion 122D of the fixed scroll 122, as shown in FIG.

[0023] 7, a first recess 122A1 having an annular shape and serving as an oil passage is formed at a predetermined position abutting against the stepped portion 144A1 of the rear housing 144 on the other surface of the bottom plate 122A of the fixed scroll 122, and a second recess 122A2 is formed at a predetermined position located at the lowest position and serving as an oil passage connecting the oil reservoir chamber H4 and the first recess 122A1. Also, a third recess 122A3 is formed on the other surface of the bottom plate 122A of the fixed scroll 122, as shown in FIGS. 7 and 8, straddling the straight portion 200A of the rear gasket 200 to connect the discharge chamber H2 and the oil reservoir chamber H4 and returning the gaseous refrigerant present at the top of the oil reservoir chamber H4 to the discharge chamber H2. Furthermore, two pin holes 122A4 are formed on the other surface of the bottom plate 122A of the fixed scroll 122, into which ends of positioning pins (not shown) fit to position the rear gasket 200 relative to the fixed scroll 122. Note that, as shown in Figs. 2 and 8, pin holes 200C through which positioning pins pass are also formed on the plate surface of the rear gasket 200.

[0024] 4, 5, and 7, a fourth recess 122D2 is formed in the outer surface of the uppermost protruding portion 122D of the fixed scroll 122. The fourth recess 122D2 serves as an oil passage that communicates with the oil passage formed by the first recess 122A1 and extends to the tip of the protruding portion 122D. Furthermore, a fifth recess 206D, which serves as an oil passage that extends in the thickness direction of the thrust plate 206, is formed in the outer surface of the thrust plate 206 at a location corresponding to the fourth recess 122D2 formed in the protruding portion 122D of the fixed scroll 122, as shown in FIG. 6. Therefore, the lubricating oil in the oil reservoir chamber H4 is supplied to the internal space of the motor housing 142 via the oil passage formed by the first recess 122A1, the second recess 122A2, and the fourth recess 122D2 of the fixed scroll 122 and the fifth recess 206D of the thrust plate 206. The lubricating oil supplied to the internal space of the motor housing 142 lubricates the various devices housed therein and is returned to the bottom. Note that the hatched portion in Fig. 6 indicates the region with which the tip of the protruding portion 122D of the fixed scroll 122 abuts.

[0025] The bottom plate 124A of the orbiting scroll 124 is formed with a plurality of through holes 124A1 located at different distances from the center of the bottom plate 124A, which supply a portion of the high-pressure gaseous refrigerant compressed in the compression chamber H3 to the other side of the bottom plate 124A. Furthermore, the other side of the bottom plate 124A of the orbiting scroll 124 is formed with a plurality of circumferential grooves 124A2, as shown in Fig. 9, into which portions of sealing members 210, such as O-rings, are fitted and which are arranged to concentrically surround the plurality of through holes 124A1. Therefore, the minute circular or annular sealed space defined by the orbiting scroll 124, the thrust plate 206, and the sealing member 210 functions as a back pressure chamber H5 that urges the orbiting scroll 124 toward the fixed scroll 122 by the high-pressure gaseous refrigerant (back pressure) supplied from the compression chamber H3 through the through holes 124A1. The cross-sectional area of ​​each through-hole 124A1 can be appropriately determined, for example, so that the back pressures supplied from the compression chamber H3 to the back-pressure chamber H5 are approximately equal. This minimizes the flow rate of gaseous refrigerant supplied or discharged between the compression chamber H3 and the back-pressure chamber H5, suppressing pressure loss due to the through-hole 124A1 and resulting changes in the state of the gaseous refrigerant. This stabilizes the back-pressure in the back-pressure chamber H5. Specifically, the volume of the back-pressure chamber H5 is small, less than one-third the volume of the discharge hole 122C of the fixed scroll 122 and less than one-fifth the minimum volume of the crescent-shaped compression chamber H3. Furthermore, because the back-pressure chamber H5 is filled with lubricant and the flow of lubricant in and out is negligibly small, the multiple through-holes 124A1 are not restricted by the restriction. In other words, even if a two-phase flow consisting of gas and fluid is introduced into the compression chamber H3, the back-pressure in the back-pressure chamber H5 can be constantly stabilized.

[0026] 9 and 10, an annular metal member 212 is disposed between the bottom plate 124A of the orbiting scroll 124 and the thrust plate 206 to ensure the formation of the back pressure chamber H5 during startup of the scroll compressor 100. The metal member 212 has an annular portion 212A made of a thin plate and a plurality of discontinuous claw portions 212B extending vertically along a predetermined length from the inner circumferential edge of the annular portion 212A. The metal member 212 is preferably made of a steel plate that is tin-plated or the like to enhance sliding characteristics. As shown in FIG. 9, the annular portion 212A is disposed in a position facing each of the circumferential grooves 124A2 of the orbiting scroll 124, and the claw portions 212B are adapted to fit into portions of the circumferential grooves 124A2. In this case, the elasticity of the seal member 210 urges the metal member 212 toward the thrust plate 206 and toward the side wall of the circumferential groove 124A2, thereby maintaining its position. In addition, since the plurality of claw portions 212B are discontinuously formed, lubricating oil is supplied to the circumferential groove 124A2 from between the adjacent claw portions 212B, which also contributes to lubrication of the seal member 210.

[0027] An annular rocking member 214 is disposed in the interior space of the motor housing 142, near its open end, at a predetermined distance from the disk portion 206A of the thrust plate 206. The rocking member 214 is integrated with the orbiting scroll 124 via rotation-preventing pins 216 that are press-fitted into a plurality of pin holes 124A3 formed concentrically on the other surface of the bottom plate 124A of the orbiting scroll 124. Therefore, the disk portion 206A of the thrust plate 206 is formed with a circular hole 206E through which the rotation-preventing pin 216 passes and slides against the inner circumferential surface to prevent rotation of the orbiting scroll 124. The circular hole 206E can also serve to introduce gaseous refrigerant from the suction chamber H1 into the scroll unit 120.

[0028] A drive shaft 218 is disposed within the interior space of the motor housing 142. The drive shaft 218 transmits a rotational driving force for orbiting the orbiting scroll 124 around the axis of the fixed scroll 122 via a swinging member 214 integrated with the orbiting scroll 124. The drive shaft 218 is an integrated member comprising a cylindrical small-diameter portion 218A, a cylindrical large-diameter portion 218B, and a frusto-conical transition portion 218C that smoothly connects the small-diameter portion 218A and the large-diameter portion 218B. A recess 218B1 with a circular cross section is formed on the end face of the drive shaft 218 on the large-diameter portion 218B side and extends a predetermined length from the end face toward the small-diameter portion 218A. The end of the small-diameter portion 218A of the drive shaft 218 is rotatably supported by the inner circumferential surface of a support portion 142B1 formed on the bottom wall portion 142B of the motor housing 142 via a bearing 220, such as a ball bearing. Furthermore, recess 218B1 formed in large diameter portion 218B of drive shaft 218 is rotatably supported by protrusion 206B of thrust plate 206, which protrudes partway toward the back of recess 218B, via two bearings 222, such as ball bearings, arranged side by side in the axial direction. Here, a through-hole 142B2 is formed at a predetermined location above support portion 142B1 of motor housing 142, which supplies gaseous refrigerant mixed with lubricating oil present in suction chamber H1 to bearing 220 to contribute to lubrication.

[0029] A rotor 162 made of a permanent magnet and constituting part of the electric motor 160 is press-fitted and fixed to the outer circumferential surface of the small-diameter portion 218A of the drive shaft 218. A stator core unit 164, around which an electromagnet is wound, is attached to a predetermined location on the inner circumferential surface of the peripheral wall portion 142A of the motor housing 142, facing the outer circumferential surface of the rotor 162 of the electric motor 160. Therefore, by supplying a direct current to the windings of the stator core unit 164, the rotor 162 made of a permanent magnet rotates due to the magnetic force generated in the stator core unit 164, thereby generating a rotational driving force for revolving the orbiting scroll 124. The structure and operation of the electric motor 160 are well known to those skilled in the art and are not essential to the present embodiment, so a detailed description thereof will be omitted in this specification.

[0030] An eccentric bushing 224 is disposed outside the large diameter portion 218B of the drive shaft 218. The eccentric bushing 224 revolves along a circular path eccentric with respect to the axis of the protruding portion 206B of the thrust plate 206 as the drive shaft 218 rotates. The eccentric bushing 224 has a cylindrical portion 224A disposed outside the large diameter portion 218B of the drive shaft 218 and a balance weight portion 224B integrated with the cylindrical portion 224A to reduce vibrations caused by the orbiting of the orbiting scroll 124. As shown in FIG. 11 , the inner diameter of the cylindrical portion 224A is larger than the diameter of the large diameter portion 218B of the drive shaft 218. Therefore, the cylindrical portion 224A of the eccentric bushing 224 is capable of moving relative to the drive shaft 218 by a dimensional difference (gap) between the cylindrical portion 224A and the drive shaft 218. In addition, a portion of the inner surface of the cylindrical portion 224A and a portion of the outer surface of the large diameter portion 218B of the drive shaft 218 are formed with flat engagement portions 224C and 218D, which serve as guide surfaces that receive the compression reaction force of the orbiting scroll 124 when the gas refrigerant is compressed by the scroll unit 120 and regulate the direction in which the eccentric bushing 224 is forced outward in the orbital radius relative to the drive shaft 218.

[0031] The outer peripheral surface of the cylindrical portion 224A of the eccentric bushing 224 is rotatably supported via a bearing 226, such as a ball bearing, on the inner peripheral surface of the swinging member 214, which orbits integrally with the orbiting scroll 124. In other words, the cylindrical portion 224A of the eccentric bushing 224 is supported via the bearing 226 arranged on the outside thereof so that at least a portion of it can be displaced circumferentially relative to the inner peripheral surface of the swinging member 214. Therefore, the radial load generated in the orbiting scroll 124 is supported by the two bearings 222 and 226 arranged inside and outside the cylindrical portion 224A of the eccentric bushing 224. As a result, the axial load on the drive shaft 218 is small, the moment that tilts it is also small, and the requirements for the bearing 220 that supports the small diameter portion 218A of the drive shaft 218 are reduced. For these reasons, even if bearing 220, which rotatably supports small diameter portion 218A of drive shaft 218, is made smaller or simpler, reliability is not impaired, and cost reduction can also be expected.

[0032] In the scroll compressor 100, when the electric motor 160 is started and the drive shaft 218 begins to rotate, the rotational force causes the orbiting scroll 124 to orbit about the axis of the fixed scroll 122 via the eccentric bushing 224, the bearing 226, the swinging member 214, and the rotation-preventing pin 216. At this time, the rotation-preventing pin 216 orbits while making sliding contact with the inner circumferential surface of the circular hole 206E of the thrust plate 206, thereby preventing the orbiting scroll 124 from rotating. When the orbiting scroll 124 orbits, the gaseous refrigerant drawn into the suction chamber H1 from the suction port P1 of the housing 140 is taken into the compression chamber H3 from near the outer end of the scroll unit 120, and is compressed as the volume of the compression chamber H3 decreases and transported to the center. At this time, a portion of the high-pressure gaseous refrigerant compressed in the compression chamber H3 is supplied to the back pressure chamber H5 via the through-hole 124A1 of the orbiting scroll 124, and the pressure of the mixed fluid of the high-pressure gaseous refrigerant and lubricating oil compressed in the multiple crescent-shaped compression chambers H3 applies a force to the back surface of the orbiting scroll 124 via the through-holes 124A1 that communicate with each of the multiple concentric back pressure chambers H5 provided on the back surface of the orbiting scroll 124. This urges the orbiting scroll 124 toward the fixed scroll 122, ensuring a seal between the fixed scroll 122 and the orbiting scroll 124.

[0033] The high-pressure gaseous refrigerant transported to the center of the scroll unit 120 is discharged into the discharge chamber H2 through the discharge hole 122C of the fixed scroll 122 and the discharge valve 202. The high-pressure gaseous refrigerant discharged into the discharge chamber H2 is discharged from the discharge port P2 to the refrigerant circuit while the lubricating oil is separated from the high-pressure gaseous refrigerant by the oil separator 204. Meanwhile, the lubricating oil separated by the oil separator 204 is supplied to the oil reservoir chamber H4 through the oil passage 144C1 of the housing 140. Here, the gaseous refrigerant present in the upper space of the oil reservoir chamber H4 is returned to the discharge chamber H2 through the third recess 122A3 of the fixed scroll 122, thereby preventing an excessive increase in pressure in the upper space of the oil reservoir chamber H4, which would lower the liquid level and reduce the amount of oil stored.

[0034] The lubricating oil in the oil reservoir H4 passes through an oil passage formed by the first recess 122A1, the second recess 122A2, and the fourth recess 122D2 of the fixed scroll 122 and the fifth recess 206D of the thrust plate 206, and is returned to the suction chamber H1 of the motor housing 142. Some of the lubricating oil returned to the suction chamber H1 drips along one surface of the thrust plate 206 that faces the internal space of the motor housing 142, and serves to lubricate, for example, the gap between the circular hole 206E of the thrust plate 206 and the rotation-preventing pin 216, and the bearings 222 and 226, before being returned to the bottom of the suction chamber H1.

[0035] By this action, the scroll compressor 100 compresses the low-pressure gas refrigerant drawn in from the suction port P1 in the scroll unit 120 to produce high-pressure gas refrigerant, and discharges it from the discharge port P2 while separating the lubricating oil from it in the oil separator 204.

[0036] Incidentally, a gap exists between the large diameter portion 218B of the drive shaft 218 and the cylindrical portion 224A of the eccentric bushing 224, which allows the eccentric bushing 224 to be displaced along the flat engagement portions 218D and 224C relative to the drive shaft 218. Therefore, when the orbiting scroll 124 orbits, the axis of the cylindrical portion 224A of the eccentric bushing 224 tilts relative to the axis of the drive shaft 218, and the balance weight portion 224B of the eccentric bushing 224 comes into contact with surrounding components, which may result in, for example, sliding resistance or abnormal noise.

[0037] 11 , the drive shaft 218 and the eccentric bushing 224 are provided with a pin 228 that extends parallel to the flat engaging portions 218D and 224C, penetrating the eccentric bushing 224 and the drive shaft 218, and regulates the inclination of the axis of the eccentric bushing 224 relative to the axis of the drive shaft 218. Specifically, the large diameter portion 218B of the drive shaft 218 and the eccentric bushing 224 are respectively formed with pin holes 218E and 224D that extend parallel to the flat engaging portions 218D and 224C and on a cross section of the drive shaft 218 when they are combined. The pin 228 is fitted into the pin holes 218E and 224D. In this manner, the pin 228 regulates the inclination of the axis of the eccentric bushing 224 relative to the axis of the drive shaft 218, preventing the balance weight portion 224B of the eccentric bushing 224 from losing its position and coming into contact with peripheral components. Furthermore, the pin 228 has the advantage of being highly durable, since it only serves to maintain the posture of the eccentric bush 224 with which the balance weight portion 224B is integrated.

[0038] At this time, in order to allow the eccentric bushing 224 to be easily displaced with respect to the drive shaft 218, it is desirable that the pin 228 be press-fitted and fixed into one of the pin hole 218E of the drive shaft 218 and the pin hole 224D of the eccentric bushing 224, and be loosely fitted into the other so as to be relatively displaceable. Furthermore, as shown in Fig. 12, both side surfaces of the pin 228 positioned in a direction perpendicular to the flat engaging portions 218D and 224C may be formed into a planar shape parallel to the flat engaging portions 218D and 224C. In this way, with regard to the gap between the pin 228 and the pin hole 218E or 224D, the gap in the direction parallel to the flat engaging portions 218D and 224C becomes larger than the gap in the direction perpendicular thereto, thereby eliminating variations in parallelism and improving productivity.

[0039] The above describes an embodiment for carrying out the present invention, but it should be noted that the present invention is not limited to the above embodiment and various modifications are possible within the scope of the technical concept of the present invention.

[0040] For example, the bearings 220, 222, and 226 are not limited to ball bearings, and may be rolling bearings such as needle roller bearings and tapered roller bearings, or plain bearings. Furthermore, the fourth recess 122D2 of the protruding portion 122D of the fixed scroll 122 may be formed as a through-hole penetrating the inside of the protruding portion 122D, rather than being formed on the outer circumferential surface of the protruding portion 122D. [Explanation of symbols]

[0041] 100 Scroll compressor (scroll fluid machinery) 122 Fixed Scroll 124 Swivel Scroll 214 Oscillating member 218 Drive shaft 218D Plane engagement part 224 Eccentric Bush 224A Cylindrical part 224B Balance weight part 224C Planar engagement part 228 pins

Claims

1. A scroll-type fluid machine comprising: a fixed scroll; an orbiting scroll meshed with the fixed scroll; a disk-shaped swinging member that is integrated with and concentrically disposed with the orbiting scroll; a drive shaft that transmits a rotational driving force that causes the orbiting scroll to revolve via the swinging member; and an eccentric bushing having a cylindrical portion that is supported at least partially circumferentially displaceable relative to an inner peripheral surface of the swinging member and has an inner diameter larger than the diameter of the drive shaft, and a balance weight portion that is integrated with the cylindrical portion, a flat engaging portion that serves as a guide for receiving a compressive reaction force of the orbiting scroll and moving the orbiting scroll in the orbiting radius direction is formed on a part of an outer peripheral surface of the drive shaft and an inner peripheral surface of the cylindrical portion, a pin extending through the eccentric bushing and the drive shaft in parallel with the flat engagement portion and restricting the inclination of the axis of the eccentric bushing relative to the axis of the drive shaft; Scroll-type fluid machinery.

2. the pin is press-fitted into one of the drive shaft and the eccentric bushing, and is fitted into the other of the drive shaft and the eccentric bushing so as to be relatively displaceable; The scroll-type fluid machine according to claim 1.

3. The pin has both side surfaces positioned in a direction perpendicular to the flat engaging portion formed in a planar shape parallel to the flat engaging portion. The scroll-type fluid machine according to claim 1 or 2.

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