JP7743291B2 - Scroll-type fluid machinery - Google Patents

Description

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.

As described in Japanese Patent Application Laid-Open No. 2008-240597 (Patent Document 1), scroll-type fluid machinery is equipped 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 the location where an eccentric bush with an integrated balance weight engages with a drive shaft that transmits rotational driving force, allowing the eccentric bush to move outward in the orbital radius relative to the drive shaft.

Japanese Patent Application Laid-Open No. 2008-240597

However, in the technology described in Patent Document 1, the drive shaft and eccentric bushing are capable of relative displacement, leaving a tiny 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.

The present invention aims to suppress the inclination of the axis of the eccentric bush relative to the axis of the drive shaft in a scroll-type fluid machine.

A scroll-type fluid machine comprises a fixed scroll, an orbiting scroll meshed with the fixed scroll, a disk-shaped rocking member integrated with and concentrically disposed with the orbiting scroll, a drive shaft that transmits the rotational driving force that revolves the orbiting scroll via the rocking member, and an eccentric bushing having a cylindrical portion supported at least partially circumferentially displaceable relative to the inner peripheral surface of the rocking member and having an inner diameter larger than that of the drive shaft, and a balance weight portion integrated with the cylindrical portion. Furthermore, flat engaging portions are formed on the outer peripheral surface of the drive shaft and on portions of the inner peripheral surface of the cylindrical portion, respectively, and serve as guides that receive the compressive reaction force of the orbiting scroll and move the orbiting scroll in the orbiting radius direction. A pin is also provided that extends parallel to the flat engaging portion and penetrates the eccentric bushing and drive shaft, restricting the inclination of the axial center of the eccentric bushing relative to the axial center of the drive shaft.

This invention makes it possible to suppress the inclination of the axis of the eccentric bush relative to the axis of the drive shaft in a scroll-type fluid machine.

FIG. 1 is a schematic cross-sectional view showing an example of a scroll compressor. FIG. 2 is a plan view showing an example of a rear gasket. FIG. 2 is a partial cross-sectional view showing an example of a rear gasket. FIG. 2 is a plan view showing an example of a fixed scroll. FIG. 2 is a perspective view showing an example of a fixed scroll. FIG. 2 is a plan view showing an example of a thrust plate. FIG. 2 is a rear view showing an example of a fixed scroll. FIG. 4 is a plan view showing the relationship between the fixed scroll and the rear gasket. FIG. 4 is an explanatory diagram of a configuration for ensuring a seal between the orbiting scroll and the thrust plate. FIG. 2 is a plan view showing an example of a metal member. 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. FIG. 10 is a cross-sectional view showing an example of a pin.

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.

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. Note that the scroll unit 120 may be driven by, for example, engine output instead of the electric motor 160. The scroll compressor 100 may also include an inverter that drives and controls the electric motor 160.

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 extends 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 extends from one surface of the bottom plate 124A. Here, the disk shape may be such that it can be recognized as a disk shape visually; for example, the outer surface may have protrusions, recesses, slits, etc. (the same applies below to shapes).

The fixed scroll 122 and the orbiting scroll 124 are arranged with their wraps 122B and 124B meshed together. Therefore, the tip 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. Meanwhile, the tip 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 tips of the wraps 122B and 124B, respectively.

Furthermore, the fixed scroll 122 and the orbiting scroll 124 are arranged so that the circumferential angles of the wraps 122B and 124B are offset from each other, 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.

The orbiting scroll 124 is positioned so that it revolves around the axis of the fixed scroll 122 while being prevented from rotating. As the orbiting scroll 124 revolves around the axis of the fixed scroll 122, the scroll unit 120 gradually reduces the volume of the crescent-shaped compression chamber H3 and moves it toward the center. As a result, the scroll unit 120 draws gaseous refrigerant into the compression chamber H3 from near the outer ends of the wrap 122B of the fixed scroll 122 and the wrap 124B of the orbiting scroll 124 and compresses it.

The housing 140 includes a motor housing 142 that primarily houses the electric motor 160, a rear housing 144 that primarily houses the scroll unit 120, and a center gasket 146 disposed between the motor housing 142 and the rear housing 144. The motor housing 142 and the rear housing 144 are separably fastened together via the center gasket 146 using fasteners (not shown), such as bolts, to form the housing 140 of the scroll compressor 100.

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 the drive shaft 218 (described below). The support portion 142B1 extends from the bottom wall portion 142B toward the other end of the peripheral wall portion 142A.

Furthermore, a suction port P1 is formed in a predetermined location on the peripheral wall portion 142A of the motor housing 142, adjacent to the bottom wall portion 142B, which draws in low-pressure gaseous refrigerant from the refrigerant circuit. Therefore, the interior space of the motor housing 142 functions as a suction chamber H1 that draws in gaseous refrigerant through the suction port P1. In the suction chamber H1, the gaseous refrigerant flows around the electric motor 160, allowing it to cool the electric motor 160. The spaces located on both axially outer sides of the electric motor 160 are connected 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 in the suction chamber H1 mixed with the lubricating oil.

The rear housing 144 is formed in a bottomed cylindrical shape, with a stepped cylindrical peripheral wall 144A consisting of a large-diameter section and a small-diameter section whose diameter changes in two stages, and a disc-shaped bottom wall 144B that closes the opening of the small-diameter section of the peripheral wall 144A. The scroll unit 120 is housed in the interior 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 part of the large-diameter section of the peripheral wall 144A, with a circular rear gasket 200 interposed between the stepped section 144A1, which is a circular flat surface that transitions from the large-diameter section to the small-diameter section. Therefore, the innermost part of the large-diameter section of the rear housing 144 is closed by the fixed scroll 122. Additionally, a discharge hole 122C is formed in the center of the bottom plate 122A of the fixed scroll 122, which discharges the high-pressure gaseous refrigerant compressed by the scroll unit 120 into the small-diameter portion of the rear housing 144. A discharge valve 202, such as 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.

A partition wall portion 144C is formed on the bottom wall portion 144B of the rear housing 144 at a predetermined location below the discharge hole 122C of the fixed scroll 122. The partition wall portion 144C extends on an inclined surface from the bottom surface of the bottom wall portion 144B toward the other side of the fixed scroll 122. As shown in FIG. 2, the rear gasket 200 has a linear portion 200A that extends linearly at a position corresponding to the formation position of the partition wall portion 144C to seal the gap between the tip of the partition wall portion 144C and the other side of the bottom plate 122A of the fixed scroll 122. Furthermore, as shown in FIG. 3, the rear gasket 200 has a protruding portion 200B that protrudes from the center of the annular outer periphery.

The small diameter portion of the rear housing 144 is therefore divided into an upper space defined by the upper surfaces of the bottom plate 122A, peripheral 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, peripheral wall 144A, bottom wall 144B, and partition 144C of the fixed scroll 122. The upper space, located at the innermost part of the rear housing 144, is fitted with, for example, a centrifugal oil separator 204 that separates lubricating oil from the high-pressure gas refrigerant compressed by the scroll unit 120. For this reason, an oil passage 144C1 is formed in a predetermined location on the partition 144C of the rear housing 144, which supplies 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, and discharges the high-pressure gaseous refrigerant from which the lubricating oil has been separated by the oil separator 204 into the refrigerant circuit.

A stepped portion 142C consisting of a circular flat surface is formed near the open end of the peripheral wall portion 142A of the motor housing 142, where the inner diameter of the peripheral wall portion 142A increases. A thrust plate 206 is positioned on the stepped portion 142C, which receives the thrust force of the orbiting scroll 124 while the gas refrigerant is compressed by the scroll unit 120. The thrust plate 206 has a circular disk portion 206A, one surface of whose periphery abuts 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.

As shown in Figures 4 and 5, the bottom plate 122A of the fixed scroll 122 is formed with multiple arc-shaped protrusions 122D extending from the outer periphery of one surface to the thrust plate 206, in order to utilize the elasticity of the rear gasket 200 to bias the thrust plate 206 toward the stepped portion 142C of the motor housing 142. The protrusions 122D are formed, for example, at three equally spaced locations on the outer periphery of the bottom plate 122A, over a predetermined length such that adjacent protrusions 122D are not adjacent. Furthermore, the tip surfaces of the two protrusions 122D each have a pin hole 122D1 that fits over the end of a positioning pin 208 (see Figure 1) that positions the thrust plate 206 relative to the fixed scroll 122. For this reason, as shown in Figure 6, the disc portion 206A of the thrust plate 206 has a pin hole 206C formed at a position corresponding to the pin hole 122D1 of the protruding portion 122D of the fixed scroll 122, into which the positioning pin 208 fits.

7, a first recess 122A1 having an annular shape is formed on the other surface of the bottom plate 122A of the fixed scroll 122. The first recess 122A1 serves as an oil passage at a predetermined location where it abuts against the stepped portion 144A1 of the rear housing 144, and a second recess 122A2 serves as an oil passage connecting the oil reservoir chamber H4 to the first recess 122A1 at a predetermined location located at the lowest position. Also, as shown in FIGS. 7 and 8, a third recess 122A3 is formed on the other surface of the bottom plate 122A of the fixed scroll 122. The third recess 122A3 straddles the straight portion 200A of the rear gasket 200, connecting the discharge chamber H2 to 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 the ends of positioning pins (not shown) fit to position the rear gasket 200 relative to the fixed scroll 122. As shown in Figures 2 and 8, a pin hole 200C through which the positioning pin passes is also formed on the plate surface of the rear gasket 200.

4, 5, and 7, a fourth recess 122D2 is formed on the outer surface of the uppermost protrusion 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 protrusion 122D. Furthermore, a fifth recess 206D, which serves as an oil passage that extends along the plate thickness direction, is formed on the outer surface of the thrust plate 206 at a location corresponding to the fourth recess 122D2 formed in the protrusion 122D of the fixed scroll 122, as shown in FIG. 6. Therefore, lubricating oil in the oil reservoir H4 is supplied to the internal space of the motor housing 142 via the oil passage formed by the first recess 122A1, second recess 122A2, and 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 area in Figure 6 indicates the area where the tip of the protruding portion 122D of the fixed scroll 122 abuts.

The bottom plate 124A of the orbiting scroll 124 is formed with multiple through-holes 124A1 located at different distances from the center of the bottom plate 124A, which supply a portion of the high-pressure gas refrigerant compressed in the compression chamber H3 to the other side of the bottom plate 124A. Also, as shown in FIG. 9 , the other side of the bottom plate 124A of the orbiting scroll 124 is formed with multiple circumferential grooves 124A2, into which portions of sealing members 210, such as O-rings, are fitted, which are arranged concentrically around the multiple through-holes 124A1. Therefore, the minute circular or annular sealed space defined by the orbiting scroll 124, thrust plate 206, and sealing member 210 functions as a back pressure chamber H5, which urges the orbiting scroll 124 toward the fixed scroll 122 by the high-pressure gas 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 gas 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 gas refrigerant, thereby stabilizing 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 negligible, 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 drawn into the compression chamber H3, the back-pressure in the back-pressure chamber H5 can be consistently stabilized.

As shown in Figures 9 and 10, a ring-shaped 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 a ring-shaped portion 212A made of a thin plate and multiple discontinuous claws 212B extending vertically along a predetermined length from the inner periphery of the ring portion 212A. The metal member 212 is preferably made of a steel plate that is tin-plated or otherwise treated to enhance sliding characteristics. As shown in Figure 9, the ring portion 212A is positioned facing each of the circumferential grooves 124A2 of the orbiting scroll 124, and the multiple claws 212B 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, allowing it to maintain its position. Furthermore, because multiple claws 212B are formed discontinuously, lubricating oil can be supplied to the circumferential groove 124A2 from between adjacent claws 212B, contributing to the lubrication of the seal member 210.

A circular rocking member 214 is disposed in the internal space of the motor housing 142, close to its open end, at a predetermined distance from the disc portion 206A of the thrust plate 206. The rocking member 214 is integrated with the orbiting scroll 124 via anti-rotation pins 216 that are press-fit into multiple pin holes 124A3 formed concentrically on the other surface of the bottom plate 124A of the orbiting scroll 124. Therefore, the disc portion 206A of the thrust plate 206 is formed with a circular hole 206E through which the anti-rotation 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.

A drive shaft 218 is disposed within the interior space of the motor housing 142. The drive shaft 218 transmits the rotational driving force that rotates 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 section 218A, a cylindrical large-diameter section 218B, and a truncated cone-shaped transition section 218C that smoothly connects the small-diameter section 218A and the large-diameter section 218B. A circular recess 218B1 is formed on the end face of the drive shaft 218 on the large-diameter section 218B side, extending a predetermined length from the large-diameter section 218B toward the small-diameter section 218A. The end of the small-diameter section 218A of the drive shaft 218 is rotatably supported by the inner circumferential surface of a support section 142B1 formed on the bottom wall section 142B of the motor housing 142 via a bearing 220, such as a ball bearing. Additionally, a recess 218B1 formed in the large-diameter portion 218B of the drive shaft 218 is rotatably supported by a protrusion 206B of the thrust plate 206, which protrudes partway toward the back of the recess 218B, via two bearings 222, such as ball bearings, arranged side by side in the axial direction. A through-hole 142B2 is formed at a predetermined location above the support portion 142B1 of the motor housing 142, which supplies gaseous refrigerant mixed with lubricating oil present in the suction chamber H1 to the bearing 220 to contribute to lubrication.

A rotor 162, consisting 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 electromagnet windings are 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 direct current to the windings of the stator core unit 164, the magnetic force generated in the stator core unit 164 rotates the rotor 162, consisting of a permanent magnet, 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 this embodiment, so a detailed description thereof will be omitted here.

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 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 generated by 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 can be displaced relative to the drive shaft 218 by the dimensional difference (gap) between the cylindrical portion 224A and the drive shaft 218. Furthermore, part of the inner circumferential surface of the cylindrical portion 224A and part of the outer circumferential surface of the large diameter portion 218B of the drive shaft 218 are formed with flat engagement portions 224C and 218D, respectively, which act as guide surfaces that receive the compression reaction force of the orbiting scroll 124 when the gaseous refrigerant is compressed by the scroll unit 120 and regulate the direction in which the eccentric bushing 224 is biased outward in the orbital radius relative to the drive shaft 218.

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 rocking 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 disposed outside it so that at least a portion of it can be displaced circumferentially relative to the inner peripheral surface of the rocking member 214. Therefore, the radial load generated on the orbiting scroll 124 is supported by the two bearings 222 and 226 disposed inside and outside the cylindrical portion 224A of the eccentric bushing 224. This reduces the axial load on the drive shaft 218, reducing the moment that tilts it, and reduces the requirements for the bearing 220 that supports the small diameter portion 218A of the drive shaft 218. For these reasons, reliability is not compromised even if the bearing 220 that rotatably supports the small diameter portion 218A of the drive shaft 218 is made smaller or simplified, and cost reductions can also be expected.

In this 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 around the axis of the fixed scroll 122 via the eccentric bushing 224, bearing 226, rocking member 214, and rotation-preventing pin 216. As the rotation-preventing pin 216 orbits while sliding against the inner circumferential surface of the circular hole 206E of the thrust plate 206, rotation of the orbiting scroll 124 is prevented. As the orbiting scroll 124 orbits, gaseous refrigerant is drawn into the suction chamber H1 from the suction port P1 of the housing 140. The gaseous refrigerant is drawn into the compression chamber H3 near the outer end of the scroll unit 120, where it is compressed and transported to the center due to the reduced volume of the compression chamber H3. At this time, a portion of the high-pressure gaseous refrigerant compressed in compression chamber H3 is supplied to back pressure chamber H5 through through-hole 124A1 of orbiting scroll 124, and the pressure of the mixed fluid of high-pressure gaseous refrigerant and lubricating oil compressed in the multiple crescent-shaped compression chambers H3 exerts a force on the back surface of orbiting scroll 124 through through-holes 124A1 that communicate with each of the multiple concentric back pressure chambers H5 provided on the back surface of orbiting scroll 124. This biases orbiting scroll 124 toward fixed scroll 122, ensuring a seal between fixed scroll 122 and orbiting scroll 124.

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 then discharged into the refrigerant circuit from the discharge port P2, with the lubricating oil separated 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, 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.

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, for example, to lubricate 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.

Through this action, the scroll compressor 100 compresses the low-pressure gas refrigerant drawn in through the suction port P1 in the scroll unit 120 to produce high-pressure gas refrigerant, which is then discharged from the discharge port P2 while the lubricating oil is separated from it in the oil separator 204.

However, there is a gap 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, causing the balance weight portion 224B of the eccentric bushing 224 to come into contact with surrounding components, which could result in, for example, sliding resistance or abnormal noise.

11, the drive shaft 218 and eccentric bushing 224 are provided with a pin 228 that extends parallel to the flat engaging portions 218D and 224C through the eccentric bushing 224 and drive shaft 218, restricting the inclination of the axial center of the eccentric bushing 224 relative to the axial center of the drive shaft 218. Specifically, the large diameter portion 218B of the drive shaft 218 and the eccentric bushing 224 are formed with pin holes 218E and 224D, respectively, that extend parallel to the flat engaging portions 218D and 224C and on the 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 way, the pin 228 restricts the inclination of the axial center of the eccentric bushing 224 relative to the axial center of the drive shaft 218, preventing the balance weight portion 224B of the eccentric bushing 224 from becoming distorted and coming into contact with surrounding components. Furthermore, the pin 228 has the advantage of being highly durable, as it only serves to maintain the position of the eccentric bushing 224, which is integrated with the balance weight portion 224B.

At this time, to allow the eccentric bushing 224 to be easily displaced relative to the drive shaft 218, it is desirable that the pin 228 be press-fitted into one of the pin hole 218E of the drive shaft 218 and the pin hole 224D of the eccentric bushing 224, while being loosely fitted into the other to allow relative displacement. Furthermore, as shown in FIG. 12, both side surfaces of the pin 228 positioned perpendicular to the planar engagement portions 218D and 224C may be formed into a planar shape parallel to the planar engagement portions 218D and 224C. In this way, the gap between the pin 228 and the pin hole 218E or 224D in the direction parallel to the planar engagement portions 218D and 224C is larger than the gap perpendicular to these, eliminating variations in parallelism and improving productivity.

The above describes an embodiment for carrying out the present invention, but please note 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.

For example, the bearings 220, 222, and 226 are not limited to ball bearings, but may also 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 that penetrates the interior of the protruding portion 122D, rather than being formed on the outer circumferential surface of the protruding portion 122D.

100 Scroll compressor (scroll fluid machine)
122 Fixed scroll 124 Orbiting scroll 214 Swing member 218 Drive shaft 218D Planar engagement portion 224 Eccentric bushing 224A Cylindrical portion 224B Balance weight portion 224C Planar engagement portion 228 Pin

Claims (3)

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. 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. 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.