Scroll compressor

Abstract

Provided is a scroll compressor in which it is possible to properly manage gaps in a sliding part in which toothed surfaces of the scroll compressor slide against each other. This scroll compressor comprises: an orbiting scroll that is provided so as to be able to orbit around an axis (O1) at a position eccentric with respect to the axis (O1); a crank pin (5) that is eccentric with respect to the axis (O1) and is provided to a rotary shaft; a drive bush (10) that has a crank pin fitting hole (10B) into which the crank pin (5) is fitted and that drives the orbiting scroll; and a coating film that is provided to toothed surfaces of the orbiting scroll and a fixed scroll. The crank pin fitting hole (10B) is provided with gaps (t1), (t2) that allow the crank pin (5) to move in one direction, and the gaps (t1), (t2) are narrower than the film thickness of the coating film.

Description

Technical Field

[0001] The present disclosure relates to a scroll compressor.Background Art

[0002] In a refrigeration / conditioning compressor, a scroll compressor is often used as a compressor that compresses a refrigerant. In the scroll compressor, oil is enclosed for lubrication of a sliding portion between facing scroll tooth surfaces and each bearing portion, but the oil is discharged to the outside of the compressor together with the refrigerant during operation. Development man-hours are required for control design to return the oil discharged to the outside of the compressor to the compressor, and the oil accumulated in a heat exchanger leads to a decrease in heat exchange efficiency. Therefore, in the development of a heat pump system, it is desired to develop a scroll compressor with a small amount of discharged oil.

[0003] In PTL 1, a seal portion that seals the flow of a fluid between the inside and the outside of a compression portion of a scroll compressor prevents a lubricant from flowing into the compression portion, and reduces the amount of oil discharged from the scroll compressor.Citation ListPatent Literature

[0004] [PTL 1] Japanese Unexamined Patent Application Publication No. 2020-51406Summary of InventionTechnical Problem

[0005] In a case where the amount of oil discharged from the scroll compressor is reduced as in PTL 1, the amount of oil guided to the compression portion is reduced, and thus the protection of a sliding surface where scroll tooth surfaces of the scroll compressor slide against each other is more important.

[0006] In order to protect the sliding portion, it is necessary to take measures of any one of (1) reducing a tooth surface load of the scroll, (2) protecting the sliding portion with a coating, or (3) making the tooth surfaces non-contacting, or a combination thereof. In a case where the non-contacting is performed as in (3), a leakage gap is increased, which leads to a decrease in compression efficiency. Therefore, it is necessary to appropriately manage a gap between the tooth surfaces.

[0007] The present disclosure has been made in view of such circumstances, and an object of the present disclosure is to provide a scroll compressor capable of appropriately managing a gap of a sliding portion where scroll tooth surfaces slide against each other.Solution to Problem

[0008] According to an aspect of the present disclosure, there is provided a scroll compressor including: a rotary shaft that extends along an axis and that rotates about the axis; an orbiting scroll that is provided to be orbitable about the axis at a position eccentric to the axis; a fixed scroll that is fixed to a housing side, that meshes with the orbiting scroll, and that forms a compression chamber for compressing a refrigerant between the fixed scroll and the orbiting scroll; a crank pin that is eccentric to the axis and that is provided on the rotary shaft; a drive bush that has a crank pin fitting hole into which the crank pin is fitted and that drives the orbiting scroll; and a coating film that is provided on a tooth surface of the orbiting scroll and / or the fixed scroll, in which the crank pin fitting hole is provided with a gap in which the crank pin is movable in one direction, and the gap is less than a film thickness of the coating film.Advantageous Effects of Invention

[0009] It is possible to appropriately manage a gap of a sliding portion where tooth surfaces of a scroll compressor slide against each other.Brief Description of Drawings

[0010] FIG. 1 is a longitudinal sectional view of a scroll compressor according to an embodiment of the present disclosure. FIG. 2 is a partially enlarged longitudinal sectional view of a seal portion in FIG. 1. FIG. 3 is a plan view of the seal portion in FIG. 1. FIG. 4 is a meshing diagram of a fixed scroll and an orbiting scroll. FIG. 5 is a plan view showing a drive bush and a crank pin. FIG. 6 is a longitudinal sectional view corresponding to FIG. 5. FIG. 7 is a plan view showing a drive bush and a crank pin. FIG. 8 is a longitudinal sectional view corresponding to FIG. 7. FIG. 9A is a plan view showing a modification example of the drive bush and the crank pin. FIG. 9B is a plan view showing another modification example of the drive bush and the crank pin. FIG. 9C is a plan view showing another modification example of the drive bush and the crank pin. Description of Embodiments

[0011] Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings.

[0012] As shown in FIG. 1, a scroll compressor 100 includes a housing 1 that forms an outer shape of the device, a drive unit 3 that is an electric motor provided in the housing 1, a rotary shaft 4 that is rotationally driven by the drive unit 3, a compression portion 2 that compresses a refrigerant by being driven by the rotation of the rotary shaft 4, a main bearing 9A and a sub-bearing 9B that rotatably support the rotary shaft 4, and a seal portion S.

[0013] The compression portion 2 and the drive unit 3 are connected to each other by the rotary shaft 4 extending along an axis O1. That is, rotational energy of the drive unit 3 is immediately transmitted to the compression portion 2 through the rotary shaft 4. The compression portion 2 compresses a refrigerant gas (refrigerant) as a working fluid by the rotational energy and discharges the refrigerant gas to the outside in a high-pressure state. The high-pressure refrigerant gas is used as a refrigerant in, for example, an air conditioner or the like.

[0014] The housing 1 is provided with a suction pipe 11 that sucks the refrigerant gas as the working fluid from the outside, and a discharge pipe 12 that discharges the refrigerant gas in a high-pressure state after being compressed by the compression portion 2. A lubricant for lubricating the main bearing 9A and the sub-bearing 9B is stored in a lower portion in the housing 1. The lubricant is supplied to the lower portion of the housing 1 via a lubricant supply pipe (not shown).

[0015] A lubricant LO stored in the lower portion of the housing 1 is guided upward by an oil pump 9B1 provided in the sub-bearing 9B. Specifically, the lubricant LO is pumped in a direction of an arrow A1 through an oil flow path (not shown) formed along the axis O1 of the rotary shaft 4, and is guided to a space between an orbiting end plate 71 of an orbiting scroll 7 and the main bearing 9A.

[0016] The rotary shaft 4 has a columnar shape centered on the axis O1. The rotary shaft 4 is rotatably supported in the housing 1 by the main bearing 9A and the sub-bearing 9B provided at an end portion on a side opposite to the axial direction when viewed from the main bearing 9A. The main bearing 9A has a main bearing body 9H that rotatably supports the rotary shaft 4. The main bearing body 9H is provided to support a load from a radial direction applied to the rotary shaft 4. The main bearing 9A has a disk shape centered on the axis O1. An outer peripheral surface of the main bearing 9A is fixed by welding, shrink-fitting, or the like in a state of being in contact with an inner peripheral surface of the housing 1 over the entire circumference. That is, the main bearing 9A partitions a space in the housing 1 into two spaces. A compression portion 2 is accommodated in a space on one side of the main bearing 9A in the axial direction. A drive unit 3 is accommodated in a space on a side opposite to the main bearing 9A in the axial direction. The suction pipe 11 described above communicates with the space (space in which the compression portion 2 is accommodated) on one side of the main bearing 9A in the axial direction.

[0017] The space inside the housing 1 is partitioned into two spaces by the main bearing 9A. The space in the housing 1 on one side of the main bearing 9A in the axial direction is a suction space V1 that accommodates the compression portion 2. The space in the housing 1 on the other side of the main bearing 9A in the axial direction is a mechanical space V2 that accommodates the drive unit 3, the main bearing 9A, and the sub-bearing 9B described above.

[0018] A crank pin 5 serving as an eccentric shaft is provided at an end portion of the rotary shaft 4 on one side. The crank pin 5 is provided at a position offset (eccentric) from the axis O1. The crank pin 5 has a columnar shape centered on an eccentric axis O2 different from the axis O1. The eccentric axis O2 is parallel to the axis O1. The crank pin 5 has a columnar shape that protrudes from the end portion of the rotary shaft 4 toward one side in the axial direction (a side on which the compression portion 2 is disposed with respect to the main bearing 9A). Therefore, in a state where the rotary shaft 4 rotates about the axis O1, the crank pin 5 revolves about the axis O1 of the rotary shaft 4.

[0019] The crank pin 5 is fitted to and connected to a drive bush 10. The drive bush 10 rotates about the axis O1 together with the crank pin 5, and is provided with a counterweight 10A to cancel out a centrifugal force. The drive bush 10 is attached to a boss portion 7A of the orbiting scroll 7, and transmits the revolving motion of the crank pin 5 about the axis O1 to the orbiting scroll 7. The crank pin 5 and the drive bush 10 will be described later.

[0020] An Oldham ring 91 is provided on a main surface (upper surface in FIG. 1: see reference numeral 9S in FIG. 2) which is a surface of the main bearing 9A facing the other side in the axial direction. The Oldham ring 91 restricts the rotation (rotation about the eccentric axis O2) of the orbiting scroll 7. Further, a thrust ring 92 for supporting a load in the axial direction applied to the rotary shaft 4 is provided on an inner peripheral side of the Oldham ring 91. The thrust ring 92 has an annular shape centered on the axis O1 when viewed in the axial direction.

[0021] A discharge cover 8 is provided on one side of the compression portion 2 in the axial direction. The discharge cover 8 is a substantially disk-like member that partitions the suction space V1 in the axial direction.

[0022] In the suction space V1, a space on one side in the axial direction with respect to the discharge cover 8 is a discharge chamber 67. A discharge port 68 that allows the discharge chamber 67 and the compression portion 2 to communicate with each other is provided in a central portion of the discharge cover 8. Further, a flow guide 69 that surrounds the discharge port 68 from an outer peripheral side is provided between the discharge cover 8 and the compression portion 2. The flow guide 69 has a cylindrical shape centered on the axis O1. The high-pressure refrigerant gas flowing out from the compression portion 2 is guided by the flow guide 69 and flows into the discharge chamber 67.

[0023] The compression portion 2 includes a fixed scroll 6 and an orbiting scroll 7 made of a metal such as an iron-based material or an aluminum alloy. The fixed scroll 6 is a substantially disk-like member fixed to one side in the axial direction of the main bearing 9A inside the housing 1. The fixed scroll 6 faces the orbiting scroll 7 from a side opposite to the main bearing 9A in the axial direction, thereby forming a compression chamber C between the fixed scroll 6 and the orbiting scroll 7.

[0024] More specifically, the fixed scroll 6 includes a disk-like fixed end plate 61 and a fixed wrap 62 that is erected in the axial direction from a surface of the fixed end plate 61 on the other side. The fixed end plate 61 extends along a surface orthogonal to the axis O1. The fixed wrap 62 is a wall body formed in a spiral shape when viewed from the axial direction. More specifically, the fixed wrap 62 is formed of a plate-like member wound around a center of the fixed end plate 61. As an example, it is desirable that the fixed wrap 62 is configured to form an involute curve centered on the axis O1 when viewed from the axial direction.

[0025] An outer peripheral wall 63 that extends in a tubular shape along an outer periphery of the fixed end plate 61 is formed on an outer side of the fixed wrap 62 in the radial direction. That is, the outer peripheral wall 63 extends from the fixed end plate 61 in the axial direction to surround the fixed wrap 62 from the outer side in the radial direction. Further, a flange portion 64 having an annular shape that extends from the inner side toward the outer side in the radial direction is provided at an end edge of the outer peripheral wall 63 on the other side in the axial direction (a side on which the drive unit 3 is disposed with respect to the main bearing 9A). The fixed scroll 6 is fixed to the main bearing 9A by a bolt (not shown) or the like via the flange portion 64. A fixed scroll discharge port 65 that penetrates the fixed end plate 61 in the axial direction is formed at a central portion of the fixed end plate 61. The fixed scroll discharge port 65 is provided with a discharge valve 66 for preventing a backflow of a refrigerant gas into the compression chamber C. The fixed scroll discharge port 65 communicates with the discharge port 68 via the flow guide 69 described above. Further, a communication hole 63H that penetrates the outer peripheral wall 63 in the radial direction is formed in a part of the outer peripheral wall 63. The communication hole 63H communicates with the inside and the outside of the compression chamber C. The communication hole 63H is formed directly beside an opening portion of the suction pipe 11 such that a position in the axial direction overlaps a connection portion between the suction pipe 11 and the housing 1. The refrigerant gas supplied from the suction pipe 11 described above to the suction space V1 flows into the fixed scroll 6 through the communication hole 63H.

[0026] The orbiting scroll 7 has a disk-shaped orbiting end plate 71 and a spiral orbiting wrap 72 provided on a surface of the orbiting end plate 71 on the other side in the axial direction. It is desirable that the orbiting wrap 72 is also configured to form an involute curve centered on an eccentric axis O2.

[0027] Further, the orbiting wrap 72 is disposed to overlap the fixed wrap 62 in a direction (radial direction) intersecting the axis O1. In other words, the fixed wrap 62 and the orbiting wrap 72 mesh with each other. In a state of being meshed in this way, a certain space (compression chamber C) is formed between the fixed wrap 62 and the orbiting wrap 72. A volume of the compression chamber C changes with the orbiting of the orbiting wrap 72. As a result, the refrigerant gas can be compressed.

[0028] The seal portion S seals the flow of the fluid between the inside and the outside of the compression portion 2 in the housing 1. The seal portion S of the present embodiment is provided to seal the flow (leakage) of the fluid between the main bearing 9A and the orbiting scroll 7. Here, the fluid includes not only a gas such as the refrigerant gas compressed in the compression chamber C but also a liquid such as the lubricant used in the main bearing 9A or the like. The seal portion S is provided on an outer peripheral side of the Oldham ring 91. As shown in FIG. 2, a main surface 9S of the main bearing 9A extends in a plane orthogonal to the axis O1. The main surface 9S faces a bearing facing surface 71A of the orbiting end plate 71 of the orbiting scroll 7, which faces the other side in the axial direction, with a gap G therebetween. The seal portion S suppresses the leakage of the refrigerant gas and the oil in the gap G in the axial direction between the main surface 9S and the bearing facing surface 71A.

[0029] Specifically, the seal portion S includes an inner peripheral seal portion Sa, an outer peripheral seal portion Sb, and a grease layer Lg. The inner peripheral seal portion Sa has an annular shape centered on the axis O1. The inner peripheral seal portion Sa is located relatively on the inner peripheral side (the inner side in the radial direction) in the seal portion S. The outer peripheral seal portion Sb has an annular shape centered on the axis O1. The outer peripheral seal portion Sb is located relatively on the outer peripheral side (the outer side in the radial direction) with respect to the inner peripheral seal portion Sa. That is, a dimension of the outer peripheral seal portion Sb in the radial direction is larger than a dimension of the inner peripheral seal portion Sa in the radial direction. Accordingly, the outer peripheral seal portion Sb surrounds the inner peripheral seal portion Sa from the outer side in the radial direction.

[0030] The inner peripheral seal portion Sa is accommodated in an inner peripheral accommodation groove 9i formed on the main surface 9S. The inner peripheral accommodation groove 9i is recessed from the main surface 9S toward the other side in the axial direction. The inner peripheral accommodation groove 9i is formed to surround the Oldham ring 91 from the outer side in the radial direction when viewed in the axial direction. The inner peripheral accommodation groove 9i has an annular shape centered on the axis O1. That is, the inner peripheral accommodation groove 9i is continuously formed in the circumferential direction with respect to the axis O1.

[0031] The outer peripheral seal portion Sb is accommodated in an outer peripheral accommodation groove 9o formed on the main surface 9S. The outer peripheral accommodation groove 9o is recessed from the main surface 9S toward the other side in the axial direction. The outer peripheral accommodation groove 9o is formed to surround the inner peripheral accommodation groove 9i from the outer side in the radial direction when viewed in the axial direction. The outer peripheral accommodation groove 9o has an annular shape centered on the axis O1. That is, the outer peripheral accommodation groove 9o is continuously formed in the circumferential direction with respect to the axis O1. A dimension of the outer peripheral accommodation groove 9o in the radial direction is larger than a dimension of the inner peripheral accommodation groove 9i in the radial direction.

[0032] The inner peripheral seal portion Sa includes an inner peripheral seal portion body S11 and an inner peripheral elastic portion S21. A part of the inner peripheral seal portion body S11 is accommodated in the inner peripheral accommodation groove 9i. A part of the inner peripheral seal portion body S11 is disposed to protrude from the main surface 9S in the axial direction. Accordingly, the inner peripheral seal portion body S11 can abut against the bearing facing surface 71A. The inner peripheral seal portion body S11 has an annular shape centered on the axis O1 (see FIG. 3). The inner peripheral seal portion body S11 is integrally formed of, for example, a resin material such as rubber or a metal material that is relatively resistant to abrasion.

[0033] The inner peripheral elastic portion S21 biases the inner peripheral seal portion body S11 toward the bearing facing surface 71A in the inner peripheral accommodation groove 9i. For example, the inner peripheral elastic portion S21 is formed of an elastic material such as silicone rubber. The inner peripheral elastic portion S21 has an annular shape centered on the axis O1, similarly to the inner peripheral seal portion body S11 (see FIG. 3). In a state of being biased by the inner peripheral elastic portion S21, a part of the inner peripheral seal portion body S11 protrudes from the inner peripheral accommodation groove 9i toward one side (bearing facing surface 71A side) in the axial direction.

[0034] The outer peripheral seal portion Sb includes an outer peripheral seal portion body S12 and an outer peripheral elastic portion S22. A part of the outer peripheral seal portion body S12 is accommodated in the outer peripheral accommodation groove 9o. A part of the outer peripheral seal portion body S12 is disposed to protrude from the main surface 9S in the axial direction. Accordingly, the outer peripheral seal portion body S12 can abut against the bearing facing surface 71A. The outer peripheral seal portion body S12 has an annular shape centered on the axis O1 (see FIG. 3).

[0035] The outer peripheral seal portion body S12 is formed of the same material as the inner peripheral seal portion body S11. Therefore, the outer peripheral seal portion body S12 is integrally formed of, for example, a resin material such as rubber or a metal material that is relatively resistant to abrasion.

[0036] The outer peripheral elastic portion S22 biases the outer peripheral seal portion body S12 toward the bearing facing surface 71A in the outer peripheral accommodation groove 9o. The outer peripheral elastic portion S22 is formed of, for example, an elastic material such as silicone rubber. The outer peripheral elastic portion S22 has an annular shape centered on the axis O1, similarly to the outer peripheral seal portion body S12 (see FIG. 3). In a state of being biased by the outer peripheral elastic portion S22, a part of the outer peripheral seal portion body S12 protrudes from the outer peripheral accommodation groove 9o toward one side (bearing facing surface 71A side) in the axial direction.

[0037] A grease layer Lg is interposed between the outer peripheral seal portion body S12 and the bearing facing surface 71A. The grease layer Lg is a thin film-shaped layer formed of an oil and fat (grease) having immiscibility with the refrigerant. That is, the grease layer Lg does not dissolve in the refrigerant gas even in a case of being in contact with the refrigerant gas.

[0038] The grease layer Lg is not provided between the inner peripheral seal portion body S11 and the bearing facing surface 71A of the orbiting scroll 7. The grease layer Lg may be interposed between at least one of the inner peripheral seal portion Sa and the outer peripheral seal portion Sb, which are disposed at a position closest to the compression chamber C, and the orbiting scroll 7.

[0039] FIG. 4 shows meshing between the fixed scroll 6 and the orbiting scroll 7. In FIG. 4, the orbiting scroll 7 is shown by hatching. A meshing point between the fixed wrap 62 of the fixed scroll 6 and the orbiting wrap 72 of the orbiting scroll 7 is indicated by a reference numeral P. The meshing point P sequentially moves in the spiral direction of each of the wraps 62 and 72 in accordance with the orbiting angle of the orbiting scroll 7. In the present embodiment, a gap between the wraps 62 and 72 (between tooth surfaces) at the meshing point P is adjusted.

[0040] A soft coating such as polytetrafluoroethylene (PTFE)-based coating is applied to substantially the entire fixed wrap 62 of the fixed scroll 6. The film thickness is, for example, about several tens of µm.

[0041] Similarly to the fixed scroll 6, a soft coating such as polytetrafluoroethylene (PTFE)-based coating is applied to substantially the entire orbiting wrap 72 of the orbiting scroll 7. The film thickness is, for example, about several tens of µm.

[0042] As shown in FIG. 5, the crank pin 5 is fitted into a crank pin fitting hole 10B formed in the drive bush 10. A planar notch surface 5A of the crank pin 5 is positioned to be in contact with a planar portion 10C of the crank pin fitting hole 10B. As a result, the drive bush 10 moves relative to the crank pin 5 in one direction, which is an extending direction (the left-right direction in FIG. 5) of the notch surface 5A of the crank pin 5.

[0043] The counterweight 10A is provided on a side opposite to an eccentricity direction (right direction in FIG. 5) in which the eccentric axis O2 is eccentric with respect to the axis O1 in FIG. 5. The counterweight 10A is provided on the left side with respect to the axis O1 in a substantially semicircular shape as shown in FIG. 5, but is not limited to this shape, and may be provided at a position rotated by a predetermined angle about the axis O1.

[0044] Side surfaces of the planar portion 10C of the crank pin fitting hole 10B on both sides are curved surfaces corresponding to the arc shape of the crank pin 5.

[0045] A gap t in one direction (extending direction of the notch surface 5A) formed between the crank pin fitting hole 10B and the crank pin 5 is less than a total film thickness of the coating films provided on the fixed wrap 62 and the orbiting wrap 72. Here, as shown in FIG. 7, the gap t is a total of one gap t1 on the left side of the crank pin 5 and the other gap t2 on the right side.

[0046] In addition, the gap t is equal to or greater than a minimum film thickness of the coating films formed on the fixed wrap 62 and the orbiting wrap 72. The minimum film thickness means a film thickness at which the total film thickness at the meshing point P (see FIG. 4) is the smallest in the spiral direction.

[0047] As shown in FIGS. 5 and 6, a relative position of the crank pin 5 with respect to the crank pin fitting hole 10B is displaced according to a wear state of the coating film, and thus gaps are formed on both sides of the crank pin 5.

[0048] In a case where the wear of the coating film progresses, the one gap t1 on the left side of the crank pin 5 is reduced, and finally, as shown in FIGS. 7 and 8, the one gap t1 becomes zero, and only the other gap t2 on the right side remains. The detail will be described later.

[0049] The operation of the scroll compressor 100 described above will be described.

[0050] In a case where the operation of the scroll compressor 100 is started, first, the drive unit 3 rotationally drives the rotary shaft 4 about the axis O1. As the rotary shaft 4 rotates, the crank pin 5 revolves about the axis O1, and the orbiting scroll 7 attached to the crank pin 5 via the drive bush 10 orbits about the axis O1 with an orbiting radius ρ. Here, the rotation of the orbiting scroll 7 is restricted by the Oldham ring 91. Therefore, the orbiting scroll 7 performs a circular motion (orbiting) about the axis O1 of the rotary shaft 4 along a trajectory drawn by the eccentric axis O2. With the orbiting, the orbiting wrap 72 of the orbiting scroll 7 repeatedly performs a continuous relative movement with respect to the fixed wrap 62 of the fixed scroll 6. With the relative movement, a volume of the compression chamber C formed between the fixed wrap 62 and the orbiting wrap 72 changes over time.

[0051] During the orbiting of the orbiting scroll 7, a refrigerant gas as a working fluid is introduced into the compression chamber C from a communication hole 63H formed in the outer peripheral wall 63 of the fixed scroll 6. The communication hole 63H is closed as the orbiting scroll 7 orbits. As a result, the refrigerant gas is confined in the compression chamber C. Subsequently, the refrigerant gas moves toward the inner side in the radial direction (that is, the eccentric axis O2 side) as the orbiting scroll 7 continues to orbit. At this time, since the orbiting wrap 72 and the fixed wrap 62 form a spiral shape, the volume of the compression chamber C formed by both the orbiting wrap 72 and the fixed wrap 62 decreases toward the inner side in the radial direction. As a result, the refrigerant gas is compressed. Finally, the refrigerant gas reaches the highest pressure in the vicinity of the center portion of the orbiting scroll 7 (or the fixed scroll 6), and then is supplied to the external refrigerant circuit through the fixed scroll discharge port 65, the discharge port 68, and the discharge pipe 12.

[0052] In the initial stage of the operation of the scroll compressor 100, since the coating films formed on the fixed wrap 62 and the orbiting wrap 72 have an initial thickness without being worn, the gap t in the crank pin 5 in the crank pin fitting hole 10B is operated in a state where gaps t1 and t2 are left on both sides of the crank pin 5 as shown in FIGS. 5 and 6. In FIG. 5, the initial operation may be performed in a state where the other gap t2 on the right side is zero. However, the gaps t1 and t2 are appropriately formed to absorb the component tolerances and the assembly tolerances of the scroll compressor 100.

[0053] As the operation of the scroll compressor 100 proceeds and the wear of the coating film progresses, a state shown in FIGS. 7 and 8 is reached. In FIGS. 7 and 8, the one gap t1 on the left side of the crank pin 5 is zero, and only the other gap t2 on the right side remains. In this state, the movement of the crank pin fitting hole 10B to the right side in FIG. 7 is restricted. This state means that the movement of the orbiting scroll 7 driven by the drive bush 10 in the centrifugal direction (direction of the fixed wrap 62) is restricted, and the orbiting wrap 72 reaches a limit of approaching the fixed wrap 62.

[0054] During the operation of the scroll compressor 100, the seal portion S is provided, so that the flow of the fluid between the main surface 9S of the main bearing 9A and the bearing facing surface 71A of the orbiting scroll 7 is sealed. As a result, the possibility that the lubricant flows into the compression chamber C can be reduced.

[0055] The operations and effects of the present embodiment described above are as follows.

[0056] The crank pin 5 is movable in one direction with respect to the drive bush 10 by the gap t provided in the crank pin fitting hole 10B. Due to the gap t, even in a case where the coating film is worn in the sliding portion between the wraps 62 and 72 of the fixed scroll 6 and the orbiting scroll 7, the orbiting scroll 7 can move in one direction via the drive bush 10. Further, even in a case where the wear of the coating film progresses and the crank pin 5 moves with respect to the drive bush 10, since the gap t is set to be less than the film thickness of the coating film, the relative movement between the drive bush 10 and the crank pin 5 is restricted by the crank pin fitting hole 10B (see FIGS. 7 and 8). As a result, even in a case where the wear of the coating film progresses, since the movement of the drive bush 10 and thus the orbiting scroll 7 can be restricted by the crank pin fitting hole 10B, the coating film can be retained at the meshing point P (see FIG. 4) between the wraps 62 and 72, and appropriate gap management between the wraps 62 and 72 (between the tooth surfaces) can be performed.

[0057] The gap t between the crank pin fitting hole 10B and the crank pin 5 defines the approach distance between the wraps 62 and 72 of the orbiting scroll 7 and the fixed scroll 6. The approach distance between the wraps 62 and 72 needs to be equal to or greater than the thickness of the coating film in order to ensure the sealing performance at the meshing point P (see FIG. 4) between the wraps 62 and 72.

[0058] On the other hand, the film thickness of the coating film formed on each of the wraps 62 and 72 varies from the design value in the spiral direction of the scrolls 6 and 7 due to the variation during manufacturing. Therefore, by setting the gap t to be equal to or greater than the minimum film thickness of the coating film, the sealing performance at the meshing point P can be ensured even at the position (orbiting position) of the coating film having the minimum film thickness.

[0059] By providing the coating film on both the orbiting scroll 7 and the fixed scroll 6, the film thickness can be made larger than in a case where the same film thickness is provided on one of the scrolls 6 and 7. As a result, the gap between the crank pin fitting hole 10B and the crank pin 5 can be set to be large, and the gap management is facilitated.

[0060] The seal portion S is provided between the orbiting end plate 71 of the orbiting scroll 7 and the main bearing 9A, and the lubricant passing through the orbiting end plate 71 and the main bearing 9A is minimized. As a result, even in a case where the oil guided between the wraps 62 and 72 of the orbiting scroll 7 and the fixed scroll 6 is minimized, the sealing performance of the wrap surface by the coating film can be maintained as described above by the gap t between the crank pin fitting hole 10B and the crank pin 5.

[0061] The present embodiment can be modified as follows.

[0062] As shown in FIG. 9A, a planar notch surface 5A may be provided on both sides of the crank pin 5. As a result, the relative movement of the crank pin 5 in one direction is more reliably performed.

[0063] As shown in FIG. 9B, the cross section of the crank pin 5 may have a triangular shape. By setting one side of the triangular shape as the notch surface 5A, the relative movement of the crank pin 5 in one direction is defined.

[0064] As shown in FIG. 9C, the cross section of the crank pin 5 may have a rectangular shape. By setting two opposite sides of the rectangular shape as the notch surface 5A, the relative movement of the crank pin 5 in one direction is more reliably performed.

[0065] In addition, in the above-described embodiment, the suction pipe 11 is provided in the suction space V1 above the main bearing 9A, but the present disclosure is not limited thereto, and the suction pipe 11 may be provided in the mechanical space V2 below the main bearing 9A.

[0066] In the above-described embodiment, the coating film is provided on both the fixed wrap 62 and the orbiting wrap 72, but the coating film may be provided on any one of the fixed wrap 62 or the orbiting wrap 72.

[0067] In the above-described embodiment, the seal portion S is provided to make it difficult for the lubricant to flow to the wrap 62 and 72 sides, but the seal portion S may be omitted.

[0068] The scroll compressor described in the above-described embodiment is understood as follows, for example.

[0069] A scroll compressor (100) according to a first aspect of the present disclosure includes a rotary shaft (4) that extends along an axis (O1) and that rotates about the axis, an orbiting scroll (7) that is provided to be orbitable about the axis at a position eccentric to the axis, a fixed scroll (6) that is fixed to a housing (1) side, that meshes with the orbiting scroll, and that forms a compression chamber (C) for compressing a refrigerant between the fixed scroll and the orbiting scroll, a crank pin (5) that is eccentric to the axis and that is provided on the rotary shaft, a drive bush (10) that has a crank pin fitting hole (10B) into which the crank pin is fitted and that drives the orbiting scroll, and a coating film that is provided on a tooth surface (62, 72) of the orbiting scroll and / or the fixed scroll, in which the crank pin fitting hole is provided with a gap (t) in which the crank pin is movable in one direction, and the gap is less than a film thickness of the coating film.

[0070] The crank pin is movable in one direction with respect to the drive bush by the gap provided in the crank pin fitting hole. Due to the gap, even in a case where the coating film is worn on a sliding portion (wrap surface) between the tooth surfaces of the fixed scroll and the orbiting scroll, the orbiting scroll can move in one direction via the drive bush. Even in a case where the wear of the coating film progresses and the crank pin moves with respect to the drive bush, since the gap is less than the film thickness of the coating film, the relative movement between the drive bush and the crank pin is restricted by the crank pin fitting hole. Accordingly, even in a case where the wear of the coating film progresses, since the movement of the drive bush and thus the orbiting scroll can be restricted by the crank pin fitting hole, the coating film can be retained on the wrap surface, and appropriate gap management of the wrap surface can be performed.

[0071] As the coating film, a soft material such as polytetrafluoroethylene (PTFE) is preferable.

[0072] In the scroll compressor according to a second aspect of the present disclosure, in the first aspect, the gap is equal to or greater than a minimum film thickness of the coating film formed on the orbiting scroll and / or the fixed scroll.

[0073] The gap between the crank pin fitting hole and the crank pin defines an approach distance between the wrap surfaces of the orbiting scroll and the fixed scroll. The approach distance on the wrap surface needs to be equal to or greater than a thickness of the coating film in order to ensure sealing performance of the wrap surface.

[0074] On the other hand, the film thickness of the coating film formed on the tooth surface of the scroll varies from a design value in a spiral direction of the scroll due to variation during manufacturing. Therefore, by setting the gap to be equal to or greater than the minimum film thickness of the coating film, the sealing performance of the wrap surface is ensured even at a position (orbiting position) where the coating film has the minimum film thickness.

[0075] In the scroll compressor according to a third aspect of the present disclosure, in the first aspect or the second aspect, the coating film is provided on both the orbiting scroll and the fixed scroll.

[0076] By providing the coating film on both the orbiting scroll and the fixed scroll, the film thickness can be made larger than in a case where the same film thickness is provided on one scroll. Accordingly, the gap between the crank pin fitting hole and the crank pin can be set to be large, and gap management is facilitated.

[0077] In the scroll compressor according to a fourth aspect of the present disclosure, in any one of the first to third aspects, a seal portion (S) is provided between an end plate of the orbiting scroll and a bearing (9A) that supports the end plate (71).

[0078] The seal portion is provided between the end plate of the orbiting scroll and the bearing, and the amount of oil passing through the end plate of the orbiting scroll and the bearing is minimized. Accordingly, even in a case where the amount of oil guided to the wrap surfaces of the orbiting scroll and the fixed scroll is minimized, the sealing performance of the wrap surface by the coating film can be maintained by the gap between the crank pin fitting hole and the crank pin as described above. Reference Signs List

[0079] 1: housing 2: compression portion 3: drive unit 4: rotary shaft 5: crank pin 5A: notch surface 6: fixed scroll 7: orbiting scroll 7A: boss portion 8: discharge cover 9A: main bearing 9B: sub-bearing 9B1: oil pump 9H: main bearing body 9S: main surface 9i: inner peripheral accommodation groove 9o: outer peripheral accommodation groove 10: drive bush 10A: counterweight 11: suction pipe 12: discharge pipe 61: fixed end plate 62: fixed wrap 63: outer peripheral wall 63H: communication hole 64: flange portion 65: fixed scroll discharge port 66: discharge valve 67: discharge chamber 68: discharge port 69: flow guide 71: orbiting end plate 71A: bearing facing surface 72: orbiting wrap 91: oldham ring 92: thrust ring 100: scroll compressor C: compression chamber G: gap Lg: grease layer LO: lubricant O1: axis O2: eccentric axis P: meshing point S: seal portion S11: inner peripheral seal portion body S12: outer peripheral seal portion body S21: inner peripheral elastic portion S22: outer peripheral elastic portion Sa: inner peripheral seal portion Sb: outer peripheral seal portion V1: suction space V2: mechanical space t: gap ρ: orbiting radius

Claims

1. A scroll compressor comprising: a rotary shaft that extends along an axis and that rotates about the axis; an orbiting scroll that is provided to be orbitable about the axis at a position eccentric to the axis; a fixed scroll that is fixed to a housing side, that meshes with the orbiting scroll, and that forms a compression chamber for compressing a refrigerant between the fixed scroll and the orbiting scroll; a crank pin that is eccentric to the axis and that is provided on the rotary shaft; a drive bush that has a crank pin fitting hole into which the crank pin is fitted and that drives the orbiting scroll; and a coating film that is provided on a tooth surface of the orbiting scroll and / or the fixed scroll, wherein the crank pin fitting hole is provided with a gap in which the crank pin is movable in one direction, and the gap is less than a film thickness of the coating film.

2. The scroll compressor according to Claim 1, wherein the gap is equal to or greater than a minimum film thickness of the coating film formed on the orbiting scroll and / or the fixed scroll.

3. The scroll compressor according to Claim 1 or 2, wherein the coating film is provided on both the orbiting scroll and the fixed scroll.

4. The scroll compressor according to Claim 1, wherein a seal portion is provided between an end plate of the orbiting scroll and a bearing that supports the end plate.

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