Scroll compressor

Abstract

[Problem] To provide a scroll compressor capable of improving assemblability of an orbiting scroll and preventing a failure which may occur in the orbiting scroll due to a rotation prevention mechanism. [Solution] In a scroll compressor 1, a rotation prevention mechanism 80 for preventing the rotation of an orbiting scroll 52 includes a plurality of circular recesses 81 formed in the back surface of an orbiting end plate 521 of the orbiting scroll 52, and a plurality of pins 82 each protruding from a support surface 135 that supports the back surface of the orbiting end plate 521 of the orbiting scroll 52. The tip of each of the plurality of pins 82 and the vicinity thereof are disposed in the corresponding circular recess 81 among the plurality of circular recesses 81. The plurality of circular recesses 81 have undergone surface hardening treatment so that at least the inner surfaces have surface hardness equal to that of the pins 82 or have surface hardness higher than that of the pins 82.

Description

Scroll compressor

[0001] The present invention relates to a scroll compressor.

[0002] Scroll compressors usually have a rotation prevention mechanism for preventing the rotation of the orbiting scroll, and a pin-ring type rotation prevention mechanism is often adopted as the rotation prevention mechanism. The pin-ring type rotation prevention mechanism includes a plurality of pins protruding from one of the back surface of the end plate of the orbiting scroll and the surface supporting the back surface of the end plate of the orbiting scroll, and a plurality of rings corresponding to the plurality of pins, the plurality of rings being fitted into a plurality of ring holes formed in the other of the back surface of the end plate of the orbiting scroll and the surface supporting the back surface of the end plate of the orbiting scroll.

[0003] Japanese Patent Application Laid-Open No. 2014-132158

[0004] However, the pin-ring type rotation prevention mechanism has the following problems. For example, when each ring is loosely fitted into the corresponding ring hole, it is necessary to assemble the orbiting scroll so that the ring does not come off from the ring hole, and the assembling property of the orbiting scroll is not good. On the other hand, when each ring is press-fitted into the corresponding ring hole, there is a risk that the ring will be deformed during the press-fitting into the ring hole, leading to a decrease in the durability of the rotation prevention mechanism. In particular, when the ring is press-fitted into the ring hole formed in the back surface of the end plate of the orbiting scroll, not only the ring but also the end plate of the orbiting scroll may be deformed during the press-fitting of the ring into the ring hole.

[0005] An object of the present invention is to provide a scroll compressor that can improve the assembling property of the orbiting scroll and prevent possible defects occurring in the orbiting scroll due to the rotation prevention mechanism.

[0006] According to one aspect of the present invention, a scroll compressor includes a fixed scroll, an orbiting scroll that performs orbital motion relative to the fixed scroll, and a rotation-preventing mechanism that prevents the orbiting scroll from rotating. The rotation-preventing mechanism includes a plurality of circular recesses formed on the back surface of the end plate of the orbiting scroll, and a plurality of pins protruding from a support surface that supports the back surface of the end plate of the orbiting scroll, the tip of each pin and its vicinity positioned within the corresponding circular recess. Each of the plurality of circular recesses is surface-hardened such that at least the inner surface has a hardness equivalent to or higher than that of the plurality of pins.

[0007] According to the present invention, it is possible to provide a scroll-type compressor that improves the ease of assembly of the orbiting scroll and prevents malfunctions that may occur in the orbiting scroll due to the rotation prevention mechanism.

[0008] This is a cross-sectional view showing the schematic configuration of a scroll-type compressor according to an embodiment. This is an enlarged view of the main part of Figure 1. This is a view of the orbiting scroll from the back side of the orbiting end plate. This is a diagram showing an example of the range of surface hardening treatment applied to the back surface of the orbiting end plate of the orbiting scroll.

[0009] Hereinafter, embodiments of the present invention will be described based on the attached drawings.

[0010] Figure 1 is a cross-sectional view showing a schematic configuration of a scroll compressor according to an embodiment of the present invention. The scroll compressor 1 according to this embodiment constitutes a part of the refrigerant circuit of a vehicle air conditioning system that is mounted on a vehicle and air-conditions the interior of the vehicle, and is configured to inhale and compress a refrigerant (gaseous refrigerant) and discharge the compressed refrigerant.

[0011] Referring to Figure 1, the scroll compressor 1 comprises a housing 10, a rotating shaft 20, a motor 30, an inverter 40, and a scroll unit 50. The rotating shaft 20, motor 30, inverter 40, and scroll unit 50 are housed in the housing 10.

[0012] The housing 10 is made of, for example, an aluminum alloy. In this embodiment, the housing 10 includes a front housing 11, a cover member 12, a center housing 13, and a rear housing 14. These front housing 11, cover member 12, center housing 13, and rear housing 14 are fastened together by bolts (not shown) to form the housing 10 of the scroll compressor 1.

[0013] The front housing 11 extends in the front-rear direction and is formed as a hollow body with openings at its front and rear ends. Specifically, the front housing 11 has a cylindrical body portion 111 having a generally circular cross-section and a non-circular body portion 112 having a non-circular cross-section. The non-circular body portion 112 is positioned in front of the cylindrical body portion 111, and the cross-section of the non-circular body portion 112 is larger than that of the cylindrical body portion 111. The internal space of the cylindrical body portion 111 and the internal space of the non-circular body portion 112 are separated by a first partition wall portion 113. The motor 30 is housed in the cylindrical body portion 111, and the inverter 40 is housed in the non-circular body portion 112.

[0014] The first bulkhead portion 113 of the front housing 11 is provided with a shaft support portion 114 that supports the front end of the rotating shaft 20. The shaft support portion 114 protrudes cylindrically from the center (it does not need to be exactly in the center, but approximately in the center) of the rear surface of the first bulkhead portion 113, that is, into the cylindrical body portion 111, and rotatably supports the portion near the front end of the rotating shaft 20 via a first bearing 21 mounted thereon.

[0015] The cover member 12 closes the opening at the front end of the front housing 11, that is, the opening of the non-circular body portion 112 in which the inverter 40 is housed.

[0016] The center housing 13 extends in the front-rear direction and is formed in a cylindrical shape corresponding to the cylindrical body portion 111 of the front housing 11, and is located behind the front housing 11. The internal space of the center housing 13 is divided into a front space and a rear space by a second partition portion 131. The front space forms a single space together with the space within the cylindrical body portion 111 of the front housing 11, and the scroll unit 50 is housed in the rear space.

[0017] The second partition wall portion 131 of the center housing 13 has a hollow projection portion 132 that protrudes forward, or more precisely, into the front housing 11. The hollow projection portion 132 is formed in the shape of a bottomed cylindrical shape with its opening facing rearward. The top portion (bottom portion of the bottomed cylinder) 133 of the hollow projection portion 132 is formed flat and faces the shaft support portion 114 provided on the first partition wall portion 113 of the front housing 11. A through hole 134 is provided in the top portion 133 of the hollow projection portion 132 through which the rotating shaft 20 passes. The through hole 134 is formed in the shape of a circle with a diameter slightly larger than the outer diameter of the rotating shaft 20, so that a minute gap is formed between the inner circumferential surface of the through hole 134 and the outer circumferential surface of the rotating shaft 20 passing through the through hole 134. A second bearing 22 is mounted inside the hollow projection portion 132 to rotatably support the portion of the rotating shaft 20 near the rear end after it has passed through the through hole 134. In other words, in this embodiment, the rotating shaft 20 extends in the front-rear direction within the housing 10 and is rotatably supported by a first bearing 21 provided in the front housing 11 and a second bearing 22 provided in the center housing 13.

[0018] The rear housing 14 is formed in a bottomed cylindrical shape corresponding to the center housing 13, and is positioned behind the center housing 13 with its opening facing forward.

[0019] Although not shown in the illustration, sealing members such as gaskets may be appropriately placed between the front housing 11 and the cover member 12, between the front housing 11 and the center housing 13, and between the center housing 13 and the rear housing 14.

[0020] The motor 30 is, for example, a three-phase synchronous motor. The motor 30 includes a stator 31 fixed to the inner circumferential surface of the cylindrical body portion 111 of the front housing 11, and a rotor 32 arranged radially inward of the stator 31 with a predetermined gap and integrated with the rotating shaft 20. The motor 30 is configured such that the rotor 32 rotates due to power supplied from the inverter 40, thereby rotating the rotating shaft 20.

[0021] The inverter 40 includes a plurality of switching elements (not shown). The inverter 40 is configured to convert DC power from the vehicle's battery (not shown) into three-phase AC power, and to drive the motor 30 by supplying this three-phase AC power to the motor 30 via a power supply line (not shown) that extends through the first bulkhead 113.

[0022] The scroll unit 50 includes a fixed scroll 51 and an orbiting scroll 52 that performs an orbital motion relative to the fixed scroll 51. The fixed scroll 51 and the orbiting scroll 52 are made of, for example, an aluminum alloy, similar to the housing 10.

[0023] The fixed scroll 51 has a disc-shaped end plate (hereinafter referred to as "fixed end plate") 511 and a spiral wall (hereinafter referred to as "fixed spiral wall") 512 formed on one surface of the fixed end plate 511. The fixed spiral wall 512 extends in a spiral shape (involute curve shape) on the one surface of the fixed end plate 511 from the radially inward inner end (winding start part) to the radially outward outer end (winding end part). The fixed scroll 51 is fixed by being sandwiched between the center housing 13 and the rear housing 14 at the outer edge (periphery) of the fixed end plate 511, with the one surface of the fixed end plate 511 (the surface on which the fixed spiral wall 512 is formed) facing forward.

[0024] The orbiting scroll 52 has a disc-shaped end plate (hereinafter referred to as "orbiting end plate") 521, a spiral wall (hereinafter referred to as "orbiting spiral wall") 522 formed on one surface of the orbiting end plate 521, and a cylindrical portion 523 projecting from the other surface of the orbiting end plate 521. The cylindrical portion 523 protrudes from the center (it does not need to be exactly in the center, but approximately in the center) of the other surface of the orbiting end plate 521. The orbiting spiral wall 522 extends along the one surface of the orbiting end plate 521 in a spiral shape (involute curve shape) from the radially inward inner end (start of winding) to the radially outward outer end (end of winding). The orbiting scroll 52 is arranged such that the orbiting spiral wall 522 engages with the fixed spiral wall 512 of the fixed scroll 51. In other words, the orbiting scroll 52 is positioned between the second partition wall 131 of the center housing 13 and the fixed scroll 51, with one of the orbiting end plates 521 (the surface on which the orbiting spiral wall 522 is formed) facing backward.

[0025] Furthermore, the other surface of the swivel end plate 521 (the surface on which the cylindrical portion 523 is formed) is supported via a plate member 23 by a support surface 135 formed on the second partition wall portion 131 of the center housing 13. The plate member 23 is formed in an annular shape and is positioned radially outward of the cylindrical portion 523 formed on the back surface of the swivel end plate 521. In the following, the other surface of the swivel end plate 521, that is, the surface opposite to the one surface facing the fixed scroll 51, on which the cylindrical portion 523 is formed, will be referred to as the "back surface" of the swivel scroll 52.

[0026] The orbiting scroll 52 is driven by the rotation of the rotation shaft 20. Specifically, the orbiting scroll 52 is driven by a driving force transmitted via the rotation shaft 20 and the conversion mechanism 70. The conversion mechanism 70 is configured to convert the rotational motion of the rotation shaft 20 into the orbital motion of the orbiting scroll 52 relative to the fixed scroll 51. Furthermore, the rotation of the orbiting scroll 52 is prevented from rotating by the rotation prevention mechanism 80. In other words, the orbiting scroll 52 is driven by the rotation of the rotation shaft 20 and is configured to perform orbital motion relative to the fixed scroll 51 while its rotation is prevented by the rotation prevention mechanism 80.

[0027] The scroll unit 50 is configured such that the orbiting scroll 52 is driven by the rotation of the rotation axis 20, causing the orbiting scroll 52 to perform an orbital motion relative to the fixed scroll 51, thereby taking in refrigerant, compressing the taken-in refrigerant, and discharging the compressed refrigerant.

[0028] Figure 2 is an enlarged view of the main part of Figure 1.

[0029] Referring to Figure 2, the conversion mechanism 70 is positioned radially inward of a cylindrical portion 523 formed on the back surface of the orbiting end plate 521 of the orbiting scroll 52. The conversion mechanism 70 includes an eccentric pin 71 and an eccentric bush 72. The eccentric pin 71 extends from the rear end face of the rotating shaft 20 in the axial direction of the rotating shaft 20. The axis of the eccentric pin 71 is offset from the axis of the rotating shaft 20. The eccentric bush 72 is rotatably attached to the eccentric pin 71, and its rear end is rotatably inserted into the cylindrical portion 523 formed on the back surface of the orbiting end plate 521 of the orbiting scroll 52 via a bearing 73. A balancer 74 is attached to the outer circumferential surface of the front end of the eccentric bush 72. The balancer 74 is provided to counteract the centrifugal force generated in the orbiting scroll 52 by the orbital motion of the orbiting scroll 52 relative to the fixed scroll 51, and to maintain an appropriate pressing force of the orbiting spiral wall 522 against the fixed spiral wall 512.

[0030] Referring to Figure 2, the rotation prevention mechanism 80 includes a plurality of substantially cylindrical recessed areas (hereinafter referred to as "circular recesses") 81 formed on the back surface of the orbiting end plate 521 of the orbiting scroll 52, and a plurality of pins 82 provided on the support surface 135 of the second partition wall portion 131 of the center housing 13. The number of circular recesses 81 and the number of pins 82 are the same.

[0031] Figure 3 shows the orbiting scroll 52 as viewed from the rear side of the orbiting end plate 521.

[0032] Referring to Figure 3, in this embodiment, a plurality (six in this case) of circular recesses 81 are formed on the orbiting end plate 521 of the orbiting scroll 52 at equal intervals in the circumferential direction on the radially outer side of the cylindrical portion 523 on the back surface. In addition, weight-reducing holes 525 are formed in each of the inter-recess regions 524 between two adjacent circular recesses 81 on the back surface of the orbiting end plate 521 of the orbiting scroll 52. The weight-reducing holes 525 are provided to reduce the weight of the orbiting scroll 52, balance its weight, and / or stabilize its shape.

[0033] Each of the multiple (in this case, six) pins 82 is made of, for example, bearing steel and is attached and fixed to a pin hole formed in the support surface 135 so as to protrude rearward from the support surface 135. The multiple pins 82 extend through the plate member 23, and as shown by the dashed lines in Figure 3, the tip of each of the multiple pins 82 and its vicinity are positioned in the corresponding circular recess 81 among the multiple circular recesses 81.

[0034] In the rotation-preventing mechanism 80, the rotation of the orbiting scroll 52 is prevented when each pin 82 contacts the inner surface (inner circumferential surface) of the corresponding circular recess 81, and the orbiting scroll 52 can perform orbital motion as each pin 82 moves along the inner surface (inner circumferential surface) of the corresponding circular recess 81. In this way, the rotation-preventing mechanism 80 prevents the rotation of the orbiting scroll 52 while allowing the orbital motion of the orbiting scroll 52, thereby causing the orbiting scroll 52 to perform orbital motion relative to the fixed scroll 51.

[0035] In this embodiment, the surface hardness of the inner surface of the circular recess 81 is lower than that of the pin 82. Therefore, there is a risk of damage or wear to the inner surface of the circular recess 81 due to contact between the inner surface of the circular recess 81 and the pin 82, and due to the movement of the pin 82 while in contact with the inner surface of the circular recess 81. Therefore, in this embodiment, each of the multiple circular recesses 81 formed on the back surface of the orbiting end plate 521 of the orbiting scroll 52 is subjected to a surface hardening treatment so that at least the inner surface that the pin 82 contacts has a surface hardness equivalent to or higher than that of the pin 82. In this embodiment, as shown by hatching in Figure 4, the surface hardening treatment is applied to the portion of the back surface of the orbiting end plate 521 of the orbiting scroll 52 other than the cylindrical portion 523.

[0036] While not particularly limited, the surface hardening treatment may be, for example, hard chrome plating. Also, while not particularly limited, the surface hardness of the inner surface of each circular recess 81 after the surface hardening treatment may be within ±10% of the surface hardness of the pin 82, or within -5% to +15% of the surface hardness of the pin 82. For example, if the surface hardness of the pin 82 is HV700 to 840, the surface hardness of the inner surface of each circular recess 81 after the surface hardening treatment may be around HV800.

[0037] Returning to Figure 1, in this embodiment, the scroll compressor 1 has an intake chamber H1, a compression chamber H2, a discharge chamber H3, a gas-liquid separation chamber H4, and a back pressure chamber H5.

[0038] The intake chamber H1 is formed by the internal space of the cylindrical body portion 111 of the front housing 11 and the front space of the center housing 13. An intake port P1 is formed in the peripheral wall of the cylindrical body portion 111 of the front housing 11. The intake port P1 is connected to the refrigerant circuit via a connecting pipe (not shown), and refrigerant from the refrigerant circuit is drawn into the intake chamber H1 via the connecting pipe and the intake port P1. The center housing 13 has a refrigerant passage L1 formed therein for guiding the refrigerant in the intake chamber H1 to the space radially outside the scroll unit 50.

[0039] The compression chamber H2 is formed between the fixed scroll 51 and the orbiting scroll 52. Specifically, in the scroll unit 50, when the orbiting scroll 52 performs an orbital motion relative to the fixed scroll 51, the orbiting spiral wall 522 comes into contact with the fixed spiral wall 512, forming a sealed space radially outward. This sealed space then moves radially inward, gradually decreasing in volume. This sealed space formed between the fixed scroll 51 and the orbiting scroll 52 is the compression chamber H2. The scroll unit 50 is configured to take in refrigerant radially outward when the compression chamber H2 (i.e., the sealed space) is formed, and compress the refrigerant as the compression chamber H2 moves radially inward.

[0040] The discharge chamber H3 is formed in the rear housing 14. A discharge hole L2 is formed approximately in the radial center of the fixed end plate 511 of the fixed scroll 51, connecting the compression chamber H2, which has moved to the radially innermost position, with the discharge chamber H3. The refrigerant compressed in the compression chamber H2 of the scroll unit 50 is discharged into the discharge chamber H3 through the discharge hole L2. A reed valve 24 is attached to the discharge hole L2, which allows the flow of refrigerant from the compression chamber H2 to the discharge chamber H3, but restricts the flow of gaseous refrigerant from the discharge chamber H3 to the compression chamber H2.

[0041] The gas-liquid separation chamber H4 is located in the rear housing 14. The gas-liquid separation chamber H4 is located behind the discharge chamber H3 and communicates with the discharge chamber H3 via a communication hole L3. An oil separator 25 is placed in the gas-liquid separation chamber H4 to separate the lubricating oil contained in the refrigerant compressed in the compression chamber H2. A discharge port P2 is provided above the oil separator 25 in the gas-liquid separation chamber H4. The discharge port P2 is connected to the refrigerant circuit via a connecting pipe (not shown) or the like.

[0042] The back pressure chamber H5 is provided on the back side of the turning end plate 521 of the turning scroll 52. Specifically, the back pressure chamber H5 is formed between the turning end plate 521 of the turning scroll 52 and the second partition portion 131 of the center housing 13. The back pressure chamber H5 includes the internal space of the hollow protruding portion 132 of the second partition portion 131. The back pressure chamber H5 communicates with the suction chamber H1 through a minute gap between the inner peripheral surface of the through hole 134 formed at the top of the hollow protruding portion 132 of the second partition portion 131 and the outer peripheral surface of the rotating shaft 20.

[0043] In the center housing 13 and the rear housing 14, a lubricating oil passage L4 is formed which connects the discharge chamber H3 and the back pressure chamber H5 and also connects the gas-liquid separation chamber H4 and the back pressure chamber H5. An orifice (constriction portion) OL is disposed in the middle of the lubricating oil passage L4.

[0044] In the scroll compressor 1 configured as described above, when the motor 30 rotates the rotating shaft 20 by power supply from the inverter 40, the rotation of the rotating shaft 20 is transmitted to the turning scroll 52 through the conversion mechanism 70, and the turning scroll 52 performs a revolution turning motion with respect to the fixed scroll 51 while its rotation is blocked by the rotation blocking mechanism 80. Then, the low-pressure refrigerant is sucked into the suction chamber H1 from the refrigerant circuit through the suction port P1. The refrigerant sucked into the suction chamber H1 passes through the refrigerant passage L1 and reaches the space on the radially outer side of the scroll unit 50, and is taken into the compression chamber H2 formed between the fixed scroll 51 and the turning scroll 52 and compressed. The high-pressure refrigerant compressed in the compression chamber H2 is discharged into the discharge chamber H3 through the discharge hole L2 and the reed valve 24, and flows into the gas-liquid separation chamber H4 through the communication hole L3. The refrigerant that has flowed into the gas-liquid separation chamber H4 is separated from the lubricating oil contained therein by the oil separator 25. Then, the refrigerant after the lubricating oil is separated is discharged from the discharge port P2 and led to the refrigerant circuit.

[0045] The lubricating oil separated from the refrigerant by the oil separator 25 is stored at the bottom of the gas-liquid separation chamber H4. In addition, a portion of the lubricating oil contained in the refrigerant discharged into the discharge chamber H3 is stored at the bottom of the discharge chamber H3. In this embodiment, the discharge chamber H3 and the gas-liquid separation chamber H4 are connected to the back pressure chamber H5 via the lubricating oil passage L4, and the back pressure chamber H5 is connected to the suction chamber H1 via a minute gap between the inner circumferential surface of the through hole 134 and the rotating shaft 20. Therefore, the lubricating oil stored at the bottom of the discharge chamber H3 and / or the lubricating oil stored at the bottom of the gas-liquid separation chamber H4 are supplied to the back pressure chamber H5 via the lubricating oil passage L4, and further supplied to the suction chamber H1. The refrigerant supplied to the suction chamber H1 is taken into the compression chamber H2 together with the low-pressure refrigerant drawn into the suction chamber H1. This ensures the lubrication of each sliding part within the housing 10.

[0046] Furthermore, a portion of the high-pressure refrigerant in the discharge chamber H3 and / or the high-pressure refrigerant in the gas-liquid separation chamber H4 is supplied to the back pressure chamber H5 via a lubricating oil passage L4 having an orifice (throttling section) OL, and the pressure in the back pressure chamber H5 is maintained at an intermediate pressure (back pressure) between the pressure in the suction chamber H1 and the pressure in the discharge chamber H3 (gas-liquid separation chamber H4). When the refrigerant is compressed, a compressive reaction force acts on the orbiting scroll 52 in a direction that separates the orbiting scroll 52 from the fixed scroll 51, but the intermediate pressure (back pressure) also acts to counteract this compressive reaction force. As a result, the orbiting scroll 52 is not pressed against the support surface 135 with excessive force, a stable orbital motion of the orbiting scroll 52 is obtained, and the contact between the fixed spiral wall 512 and the orbiting end plate 521 and the contact between the orbiting spiral wall 522 and the fixed end plate 511 can be properly maintained.

[0047] Also, in the rotation prevention mechanism 80 of the present embodiment, each of the plurality of circular recesses 81 is subjected to a surface hardening treatment so that at least the inner surface has the same surface hardness as the plurality of pins 82 or a higher surface hardness than the pins 82. Specifically, in the present embodiment, each of the plurality of pins 82 is formed of a bearing steel material, and a hard chrome plating treatment is employed as the surface hardening treatment. Therefore, damage, wear, etc. on the inner peripheral surface of the circular recess 81 are prevented by the contact between the inner surface of the circular recess 81 and the pins 82 and the movement of the pins 82 in the state where both are in contact, and smooth sliding of the pins 82 with respect to the inner surface of the circular recess 81 can be ensured over a long period.

[0048] Further, in the rotation prevention mechanism 80 of the present embodiment, different from the pin ring type rotation prevention mechanism, a ring fitted into a ring hole is not used. Therefore, the number of parts of the rotation prevention mechanism 80 is reduced, and the assemblability of the swivel scroll 52 can be improved. And since it is not necessary to attach parts to the swivel end plate 521 of the swivel scroll 52 by press fitting or the like in order to provide the rotation prevention mechanism 80, problems (ring deformation or swivel end plate 521 deformation) that may occur in the swivel scroll 52 due to the rotation prevention mechanism can also be prevented.

[0049] Also, in the above-described embodiment, the surface hardening treatment is performed on portions other than the cylindrical portion 523 on the back surface of the swivel end plate 521 of the swivel scroll 52. Therefore, damage, wear, etc. on the back surface of the swivel end plate 521 are also prevented, and smooth sliding of the swivel end plate 521 with respect to the plate member 23 can be ensured.

[0050] Note that in the above-described embodiment, the pins 82 are formed of a bearing steel material, and a hard chrome plating treatment is employed as the surface hardening treatment. However, it is not limited thereto. It is only necessary that each of the plurality of circular recesses 81 is subjected to a surface hardening treatment so that at least the inner surface of the plurality of circular recesses 81 has the same surface hardness as the plurality of pins 82 or a higher surface hardness than the pins 82, and the material of the pins 82 and the type of the surface hardening treatment can be arbitrarily selected.

[0051] Furthermore, in the above-described embodiment, the surface hardening treatment is applied to the portion of the back surface of the orbiting end plate 521 of the orbiting scroll 52 other than the cylindrical portion 523. However, it is not limited to this. It is sufficient that the surface hardening treatment is applied to the inner surfaces of at least a plurality of circular recesses 81, and the surface hardening treatment may be applied only to the inner surface of each circular recess 81 on the back surface of the orbiting end plate 521, or only to the surface (inner surface and inner bottom surface) of each circular recess 81.

[0052] Furthermore, in the above-described embodiment, weight-reducing holes 525 are formed in all inter-recess regions 524. However, this is not the only limitation. It is sufficient if weight-reducing holes 525 are formed in at least one inter-recess region 524. Also, the shape of the weight-reducing holes 525 can be arbitrarily set.

[0053] Although embodiments and modifications thereof of the present invention have been described above, the present invention is not limited to the embodiments and modifications described above, and further modifications and changes are possible based on the technical concept of the present invention.

[0054] 1...Scroll compressor, 10...Housing, 20...Rotating shaft, 21...First bearing, 22...Second bearing, 23...Plate member, 30...Motor, 40...Inverter, 50...Scroll unit, 51...Fixed scroll, 52...Orbiting scroll, 70...Conversion mechanism, 80...Rotation prevention mechanism, 81...Circular recess, 82...Pin, 135...Support surface, 511...Fixed end plate, 512...Fixed spiral wall, 521...Orbiting end plate, 522...Orbiting spiral wall, 523...Cylindrical section, 524...Area between recesses, 525...Weight-reducing holes, H1...Intake chamber, H2...Compression chamber, H3...Discharge chamber, H4...Gas-liquid separation chamber, H5...Back pressure chamber, P1...Intake port, P2...Discharge port

Claims

1. A scroll compressor comprising: a fixed scroll; an orbiting scroll that performs orbital orbital motion relative to the fixed scroll; and a rotation-preventing mechanism that prevents the rotation of the orbiting scroll, wherein the rotation-preventing mechanism comprises: a plurality of circular recesses formed on the back surface of the end plate of the orbiting scroll; and a plurality of pins protruding from a support surface that supports the back surface of the end plate of the orbiting scroll, the tip of each pin and its vicinity positioned within a corresponding circular recess among the plurality of circular recesses, wherein each of the plurality of circular recesses is subjected to a surface hardening treatment such that at least the inner surface has a surface hardness equivalent to or higher than that of the plurality of pins.

2. The scroll compressor further includes: a rotating shaft that is rotatably supported; a motor that rotates the rotating shaft; and a conversion mechanism that converts the rotation of the rotating shaft into the orbital motion of the orbital scroll relative to the fixed scroll, the conversion mechanism being arranged radially inward of a cylindrical portion that protrudes from the back surface of the end plate of the orbital scroll, wherein the plurality of circular recesses are arranged at equal intervals in the circumferential direction on the radially outward side of the cylindrical portion on the back surface of the end plate of the orbital scroll, a weight-reducing hole is formed in at least one of the inter-recess regions between two adjacent circular recesses on the back surface of the end plate of the orbital scroll, and the surface hardening treatment is applied to the portion of the back surface of the end plate of the orbital scroll other than the cylindrical portion.

3. The scroll compressor according to claim 1 or 2, wherein each of the plurality of pins is formed of bearing steel and mounted on the support surface, and the surface hardening treatment is hard chrome plating.

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