Scroll-type fluid machinery

Abstract

To provide a scroll-type fluid machine equipped with a low-cost rotation preventing mechanism having satisfactory assemblability.SOLUTION: A scroll-type fluid machine comprises a rotation preventing mechanism 36 that prevents rotation of a movable scroll without interfering with orbital revolution movement of the movable scroll with respect to a fixed scroll that is fixed to a casing. The rotation preventing mechanism 36 has: a substantially-annular accommodation groove 42 that is perforated in a substrate 16a on which a spiral wall of the movable scroll is erected and in which its own central axis is parallel to the orbital axis of the orbital revolution movement; a pin 38 that is fixed to a pedestal part 4a of the casing and protrudes into the accommodation groove 42 so that its own central axis is parallel to the orbital axis; and a ring 40 that is received in the accommodation groove 42, and has its own outer peripheral surface capable of sliding or rolling relative to a large-diameter inner wall 42a of the accommodation groove 42 and its own inner peripheral surface capable of sliding or rolling relative to the pin 38.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a scroll-type fluid machine, and more particularly to a scroll-type fluid machine that can be used in the refrigeration circuit of an air conditioner for a vehicle. [Background technology]

[0002] Conventionally, scroll-type fluid machines are provided with a rotation-preventing mechanism that prevents the rotation of the movable scroll without interfering with the orbital motion of the movable scroll relative to a fixed scroll fixed to a casing (see, for example, Patent Document 1).

[0003] The rotation-preventing mechanism of Patent Document 1 is configured with a rotation-preventing pin attached to protrude from the base of the casing, a disk with an eccentric hole into which the rotation-preventing pin engages, and multiple disk accommodating holes provided in the movable scroll. The disk accommodating holes are drilled in the back surface of a base plate facing the base and on which the spiral wall of the movable scroll is erected.

[0004] This rotation-preventing mechanism is a so-called pin-and-disk type mechanism that has four sets of rotation-preventing pins and disks. In this pin-and-disk type rotation-preventing mechanism, the use of disks increases the sliding area where Hertzian contact stress occurs in the mechanism, thereby reducing the surface pressure on the sliding surfaces and effectively suppressing wear and seizure of the rotation-preventing pins. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-86765 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the disks, which require a certain volume, are expensive parts, which in turn increases the manufacturing cost of the scroll-type fluid compression machine.

[0007] Furthermore, pin-and-disk type rotation-preventing mechanisms have the problem of poor assembly. Specifically, in manufacturing, it is necessary to engage the spiral walls of the fixed scroll and the movable scroll with a disk of approximately the same size as each of the multiple receiving holes, with a clearance fit. It is inevitable that variations will occur when forming the multiple receiving holes, and assembling the disks into these with precision is time-consuming, which has hindered the productivity of scroll-type fluid machinery.

[0008] SUMMARY OF THE INVENTION In view of the above circumstances, the present invention aims to provide a scroll-type fluid machine equipped with a rotation-preventing mechanism that is low cost and easy to assemble. [Means for solving the problem]

[0009] The present invention relates to a scroll-type fluid machine equipped with a rotation-preventing mechanism that prevents rotation of a movable scroll without interfering with the orbital orbital motion of the movable scroll relative to a fixed scroll fixed to a casing, and the rotation-preventing mechanism comprises: a substantially annular accommodating groove that is formed in a base plate on which a spiral wall of the movable scroll is erected, the groove having a central axis parallel to the orbital axis of the orbital orbital motion; a pin that is fixed to a base portion of the casing and protrudes into the accommodating groove so that the central axis of the pin is parallel to the orbital axis; and a ring that is accommodated in the accommodating groove, the outer peripheral surface of which can slide or roll relatively against the large-diameter inner wall of the accommodating groove, and the inner peripheral surface of which can slide or roll relatively against the pin. The difference in size between the outer diameter of the pin and the inner diameter of the ring is smaller than the difference in size between the outer diameter of the ring and the groove width of the receiving groove. The present invention relates to a scroll-type fluid machine characterized by the above features. [Effects of the Invention]

[0010] The scroll-type fluid machine of the present invention can provide the excellent effect of providing a low-cost, easy-to-assemble scroll-type fluid machine equipped with a rotation-preventing mechanism. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a vertical cross-sectional view showing an example of a scroll-type fluid machine according to an embodiment of the present invention. [Figure 2] FIG. 2 is a plan view showing an outline of the scroll unit of the present embodiment. [Figure 3] 2A and 2B are diagrams showing the rotation-preventing mechanism of the present embodiment, in which (A) is a plan view of the scroll unit, (B) is a plan view of the rotation-preventing mechanism, and (C) is a cross-sectional view taken along line XX of (B). [Figure 4] 1A to 1C are diagrams showing the rotation-preventing mechanism of the present embodiment, in which (A) is a plan view of the scroll unit, (B) is a plan view of the rotation-preventing mechanism, and (C) is a plan view of the rotation-preventing mechanism. [Figure 5] FIG. 2 is a plan view of a scroll unit illustrating the orbital motion of the present embodiment. [Figure 6] 1A and 1B are diagrams showing the rotation-preventing mechanism of the present embodiment, in which (A) is a plan view of the scroll unit, (B) is a plan view of the rotation-preventing mechanism, and (C) is a cross-sectional view taken along line YY in (B). [Figure 7] 1A to 1C are diagrams showing the rotation-preventing mechanism of the present embodiment, in which (A) is a plan view of the scroll unit, (B) is a plan view of the rotation-preventing mechanism, and (C) is a plan view of the rotation-preventing mechanism. [Figure 8] 1A and 1B are diagrams showing the rotation-preventing mechanism of the present embodiment, in which (A) is a plan view of the scroll unit, (B) is a plan view of the rotation-preventing mechanism, and (C) is a cross-sectional view taken along line ZZ of (B). [Figure 9] 1A to 1C are diagrams showing the rotation-preventing mechanism of the present embodiment, in which (A) is a plan view of the scroll unit, (B) is a plan view of the rotation-preventing mechanism, and (C) is a plan view of the rotation-preventing mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Figures 1 to 4 show an example of an embodiment of the present invention, and in the figures, parts with the same reference numerals represent the same configuration. In addition, some components are omitted as appropriate in each figure to simplify the drawings. In addition, the shapes and dimensions of some components are exaggerated as appropriate in each figure.

[0013] First Embodiment <Overall configuration of scroll-type fluid machinery> 1 is a longitudinal sectional view showing an example of a scroll-type fluid machine 1 according to an embodiment of the present invention. In this embodiment, the scroll-type fluid machine 1 will be described as an open scroll compressor (hereinafter simply referred to as "compressor 1") incorporated in a refrigeration circuit of a vehicle air conditioner mounted on a vehicle (not shown). The refrigeration circuit has a refrigerant circulation path for a refrigerant, which is the working fluid of the compressor 1, and the compressor 1 draws in the refrigerant from the return path of the refrigerant circulation path, compresses the refrigerant, and discharges it toward the forward path of the refrigerant circulation path.

[0014] As shown in FIG. 1, compressor 1 includes a rear casing 2 and a front casing (casing) 4. A scroll unit 6 is disposed between the rear casing 2 and the front casing 4. A drive shaft 8 is disposed within the front casing 4 and is rotatably supported by the front casing 4 via a bearing 51. The drive shaft 8 is formed in a stepped shape having an eccentric bushing 8a and a large-diameter shaft portion 8b. In addition, a base portion 4a is provided on the front casing 4 so as to protrude inward.

[0015] A drive pulley 12 incorporating an electromagnetic clutch 10 is attached to the end of the drive shaft 8 that protrudes from the front casing 4. The drive pulley 12 is rotatably supported on the front casing 4 via a bearing 52. The power of the vehicle engine is transmitted to the drive pulley 12 via a drive belt (not shown), and the rotation of the drive pulley 12 can be transmitted to the drive shaft 8 via the electromagnetic clutch 10. Therefore, when the electromagnetic clutch 10 is turned on while the engine is running, the drive shaft 8 rotates integrally with the drive pulley 12.

[0016] The scroll unit 6 includes a fixed scroll 14 and a movable scroll 16. The movable scroll 16 is assembled so as to mesh with the fixed scroll 14. The fixed scroll 14 is positioned between the rear casing 2 and the front casing 4, and is fixed to the rear casing 2 and the front casing 4 by a plurality of fixing bolts 50 extending in the axial direction of the drive shaft 8, as indicated by the dashed dotted line, and is sandwiched between them.

[0017] The fixed scroll 14 includes, for example, a base plate 14 a, and a spiral wall 14 b is provided on the base plate 14 a facing the movable scroll 16 .

[0018] The movable scroll 16 also includes, for example, a base plate 16a, and a spiral wall 16b is provided on the base plate 16a facing the fixed scroll 14. A back surface 16c of the base plate 16a of the movable scroll 16 is positioned opposite the pedestal portion 4a of the front casing.

[0019] The outer periphery of the spiral wall 14b of the fixed scroll 14 abuts against the end wall 4b of the front casing 4, and the base plate 16a of the movable scroll 16 is positioned within the front casing 4. A refrigerant suction chamber 20 is defined between the end wall 4b of the front casing 4 and the base plate 16a. The suction chamber 20 is connected to the return path of the refrigerant circulation path described above.

[0020] A base plate 14a of the fixed scroll 14 abuts against an end wall 2a of the rear casing 2. A refrigerant discharge chamber 22, partitioned by the base plate 14a, is formed within the rear casing 2, and the outgoing path of the refrigerant circulation path described above is connected to the discharge chamber 22. The discharge chamber 22 also communicates with the compression chamber 18 via a discharge hole 24 drilled in the base plate 14a of the fixed scroll 14. A discharge valve (not shown) that opens and closes the discharge hole 24 is disposed in the discharge chamber 22, and the opening degree of the discharge valve is regulated by a stopper plate 28.

[0021] A reinforcing portion (boss) 30 protrudes from the back surface 16c of the base plate 16a of the movable scroll 16, and an eccentric bushing 8a is rotatably inserted into the inside of the boss 30 via a bearing 53. The eccentric bushing 8a is, for example, in the shape of a disk having a hole 8ah that is eccentric with respect to the axis of the drive shaft 8 (shown by the dashed line). The large-diameter shaft portion 8b has an engaging portion 8bc that protrudes toward the eccentric bushing 8a. The engaging portion 8bc is inserted into the hole 8ah, so that the eccentric bushing 8a rotates eccentrically with respect to the axis of the drive shaft 8 as the drive shaft 8 rotates.

[0022] A rotation-preventing mechanism 36 is disposed between the back surface 16c of the base plate 16a of the movable scroll 16 and the pedestal portion 4a of the front casing 4. As a result, the movable scroll 16 revolves around the axis of the drive shaft 8 (i.e., relative to the fixed scroll 14) as the eccentric bushing 8a rotates. A balancer weight 35 is attached to the eccentric bushing 8a to counteract the centrifugal force generated when the movable scroll 16 moves.

[0023] In addition, a ring-shaped thrust plate 34 is disposed between the back surface 16c of the base plate 16a of the movable scroll 16 and the pedestal portion 4a of the front casing 4. When the movable scroll 16 revolves, the back surface 16c of the base plate 16a of the movable scroll 16 slides against the thrust plate 34.

[0024] Additionally, in this compressor 1, a crank chamber 37 for a refrigerant containing lubricating oil is provided between the back surface 16c of the base plate 16a of the movable scroll 16 and the thrust plate 34. The crank chamber 37 is connected to the suction chamber 20 on the outer circumferential side of the base portion 4a, and as the movable scroll 16 revolves, refrigerant flows into the crank chamber 37 from the suction chamber 20 side toward the compression chamber 18 side, thereby adjusting the pressure in the crank chamber 37 to between the suction chamber 20 and the compression chamber 18.

[0025] The pressure in the crank chamber 37 and the rotation-preventing mechanism 36 do not impede the orbital motion of the movable scroll 16, and the movable scroll 16 is suitably pressed against the fixed scroll 14. The lubricating oil that flows together with the refrigerant into the crank chamber 37 lubricates the back surface 16c of the movable scroll 16 and the sliding surface 34a of the thrust plate 34 against which the back surface 16c slides, as well as the rotation-preventing mechanism 36, and the crank chamber 37 also functions as a lubricating oil passage.

[0026] 2 is a schematic plan view of the scroll unit 6 as viewed from the direction of line VV in FIG. 1. The center (axial center) 14CT of the fixed scroll 14 coincides with the axial center of the drive shaft 8, and the center (axial center) 16CT of the movable scroll 16 is assembled eccentrically relative to the center (axial center) 14CT of the fixed scroll 14. The fixed scroll 14 and the movable scroll 16 are disposed opposite each other such that the circumferential angles of the respective spiral walls 14b, 16b are offset from each other and the side walls of the spiral walls 14b, 16b are in partial contact with each other. The respective spiral walls 14b, 16b of the fixed scroll 14 and the movable scroll 16 are opposed to each other and mesh with each other, forming a fluid pocket 18, which is a crescent-shaped sealed space, between the respective spiral walls 14b, 16b. In this example, the fluid pocket 18 serves as a compression chamber for a refrigerant, which is a working fluid containing lubricating oil.

[0027] 1 and 2, in compressor 1, when drive pulley 12 rotates, drive shaft 8 rotates via electromagnetic clutch 10, and as drive shaft 8 rotates, movable scroll 16 revolves around axis 14CT of fixed scroll 14 (centered on axis 14CT (axis of drive shaft 8)) in, for example, a clockwise direction with an orbital radius AOR determined by contact between scroll walls 14b, 16b. At this time, movable scroll 16 revolves while its back surface 16c slides against thrust plate 34, while its rotation is prevented by rotation-preventing mechanism 36. The volume of fluid pocket (compression chamber) 18 increases or decreases as movable scroll 16 revolves relative to fixed scroll 14.

[0028] That is, while the spiral walls 14b, 16b are in contact with each other, the compression chamber 18 formed therebetween moves from the outer end of the spiral walls 14b, 16b toward the center, and its volume decreases. When the volume of the compression chamber 18 decreases, the fluid (e.g., refrigerant gas) drawn into the compression chamber 18 from the outer end side of the spiral walls 14b, 16b is compressed. As a result, the refrigerant drawn into the suction chamber 20 from the return path of the refrigerant circulation path is compressed while moving toward the center of the scroll unit 6 within the compression chamber 18, and then discharged into the discharge chamber 22 through the discharge hole 24 and sent from the discharge chamber 22 to the outward path of the refrigerant circulation path.

[0029] <Rotation prevention mechanism> A rotation-preventing mechanism 36 according to a first embodiment of the present invention will be described with reference to Figures 3 to 5. Figure 3(A) is a diagram showing an outline of the scroll unit 6 (substrate 16a side), and is a plan view viewed from the direction of line VV in Figure 1. Figure 3(B) is a plan view showing one set of rotation-preventing mechanisms 36, and Figure 3(C) is a cross-sectional view taken along line XX in Figure 3(B).

[0030] As shown in Fig. 3(A), multiple sets (four sets in this example) of rotation-preventing mechanisms 36 are provided for one substrate 16a. As shown in Fig. 3(B), rotation-preventing mechanisms 36 of this embodiment have a housing groove 42, a rotation-preventing pin 38 (hereinafter sometimes simply referred to as a "pin"), and a ring 40.

[0031] As shown in FIGS. 3B and 3C, the accommodation groove 42 is formed in the back surface 16c of the base plate 16a on which the spiral wall 16b of the movable scroll 16 is erected. The accommodation groove 42 is formed in a substantially annular shape, with its central axis parallel to the axis of revolution of the orbital motion (the center (axial center) 14CT of the fixed scroll 14, the axial center of the drive shaft 8). More specifically, the accommodation groove 42 is formed by leaving a portion of the base plate 16a in an area including the central axis in a convex shape toward the base portion 4a and hollowing out the surrounding portion of the base plate 16a in a substantially annular shape. The accommodation groove 42 has a large-diameter inner wall (hereinafter referred to as the "large-diameter side inner wall 42a") located on the radially outer side, a small-diameter inner wall (hereinafter referred to as the "small-diameter side inner wall 42b") located on the radially inner side, and a bottom surface 42c.

[0032] The pin 38 is a cylindrical member that is fixed (for example, by press-fitting) to the base portion 4a of the front casing 4, and has a protrusion 38a that protrudes into the accommodating groove 42 (toward the base plate 16a of the movable scroll 16) so that its central axis is parallel to the orbital axis of the orbital rotation motion (the center (axis) 14CT of the fixed scroll 14, the axis of the drive shaft 8).

[0033] The ring 40 is accommodated in the accommodation groove 42, and the pin 38 (protrusion 38a) is disposed inside the accommodation groove 42. The ring 40 has a generally circular (cylindrical) shape and has an outer peripheral surface 40a that forms the radially outer side of the ring 40, an inner peripheral surface 40b that forms the radially inner side, and a sliding surface 40c that faces in the direction of its central axis. The ring 40 engages with the pin 38 (protrusion 38a) by a clearance fit.

[0034] As a result, the inner peripheral surface 40b of the ring 40 can slide or roll relative to the outer peripheral surface 38b of the pin 38 as the movable scroll 16 revolves. Also, as the movable scroll 16 revolves, the outer peripheral surface 40a of the ring 40 can slide or roll relative to the large-diameter inner wall 42a of the accommodation groove 42. Also, as the movable scroll 16 revolves, each sliding surface 40c can slide against the bottom surface 42c of the accommodation groove 42 and the sliding surface 34a of the thrust plate 34, respectively.

[0035] In this example, a portion of the accommodation groove 42 is in communication with the crank chamber 37. The lubricating oil in the crank chamber 37 is taken into the accommodation groove 42 as the movable scroll 16 revolves and revolves, and contributes to lubrication when the ring 40 slides or rolls relative to the pin 38 and the accommodation groove 42, as well as lubrication between each sliding surface 40c of the ring 40 and the sliding surface 34a of the thrust plate 34 and the bottom surface 42c of the accommodation groove 42.

[0036] The rotation-preventing mechanism 36 of this embodiment accommodates a pin 38 in a substantially annular accommodation groove 42, and prevents the rotation of the movable scroll 16 by direct or indirect collision (contact) between the accommodation groove 42 and the pin 38.

[0037] The movable scroll 16, i.e., the housing groove 42, is made of, for example, a light alloy (e.g., an aluminum alloy), while the pin 38 and the ring 40 are both made of a high-hardness iron-based material such as chromium-molybdenum steel (e.g., SCM415).

[0038] The surface hardness of the pin 38 and ring 40 is approximately 60 to 64 in HRC (Rockwell hardness) (equivalent to approximately 697 to 800 in HV (Vickers hardness)), and the surface hardness of the receiving groove 42 is approximately 150 in HV. The coefficient of friction between the aluminum alloy and chrome molybdenum steel is 0.02 to 0.05 with fluid lubrication.

[0039] In other words, when the rotation-preventing mechanism 36 functions, the pin 38 and the housing groove 42, which have different surface hardnesses, collide (contact) and slide against each other, causing wear and deterioration of the housing groove 42. Therefore, a ring 40 is provided that can slide or roll relative to both the pin 38 and the housing groove 42. Furthermore, a small gap (a predetermined dimensional difference) is ensured between the pin 38 and the ring 40, and between the ring 40 and the housing groove 42. This improves the sliding ability between the pin 38 and the housing groove 42, reduces wear and deterioration of the housing groove 42, and reduces the PV value. The dimensional difference will be described later.

[0040] The orbital motion will be described with reference to Figures 4 and 5. Figure 4(A) is a plan view showing Figure 3(A) with the axis 14CT of the fixed scroll 14 and the axis 16CT of the movable scroll 16 superimposed thereon, and Figure 4(B) is a plan view of a set of rotation-preventing mechanisms 36 showing the maximum allowable orbital radius LPOR of the movable scroll 16. Figure 4(C) is a plan view of a set of rotation-preventing mechanisms 36 showing the minimum allowable orbital radius SPOR of the movable scroll 16. Figure 5 is a plan view showing the state of motion of the movable scroll 16.

[0041] 4(A), the accommodation groove 42 of the movable scroll 16 is provided so that its center is positioned on the same line as the axis 16CT of the movable scroll 16. The pin 38 is press-fitted into the fixed scroll 14 so that its center is positioned on the same line as the axis 14CT of the fixed scroll 14. As the drive shaft 8 rotates, the axis 16CT of the movable scroll 16 moves (orbits) around the axis 14CT of the fixed scroll 14, for example, in a clockwise direction. Accordingly, the accommodation groove 42 provided in the movable scroll 16 orbits around the pin 38 fixed to the fixed scroll 14, with the pin 38 as the center.

[0042] The following description will be given in chronological order with reference to Figure 5. Figure 5(A) shows the state shown in Figure 4(A), and Figures 5(B) to 5(D) show states in which the axis 16CT of the movable scroll 16 has rotated clockwise by 90 degrees from the state shown in Figure 5(A). The large dashed lines in Figures 5(B) to 5(D) show the state of the movable scroll 16 in Figure 5(A).

[0043] As a result of the axis 16CT of the movable scroll 16 orbiting around the axis 14CT of the fixed scroll 14 (moving eccentrically with respect to the drive shaft 8), the four sets of accommodation grooves 42 move around the pins 38 accommodated inside them. In detail, the large-diameter side inner walls 42a of the accommodation grooves 42 indirectly abut against the pins 38 via the ring 40, i.e., move outward while engaging with the pins 38.

[0044] At the same time, a force P1 is applied to the movable scroll 16 in a direction that causes it to rotate about its axis 16CT. In other words, the movable scroll 16 attempts to rotate such that a diametrical line passing through the axis 16CT tilts about the axis 16CT, as shown by the two-dot chain line in FIG. 5(A). However, at this time, as shown in FIG. 4(B), the large-diameter inner wall 42a of the accommodation groove 42 collides (indirectly abuts) against the pin 38 via the ring 40, preventing the movable scroll 16 from rotating about the axis 16CT. In this way, the movable scroll 16, while prevented from rotating about its axis 16CT by the rotation-preventing mechanism 36, revolves around the axis 14CT of the fixed scroll 14 (the axis of the drive shaft 8), as shown in FIGS. 5(A) to 5(D).

[0045] Furthermore, in the compressor 1 (particularly the open-type scroll compressor) of this embodiment, the movable scroll 16 may move due to the expansion of the remaining high-pressure gas when the electromagnetic clutch 10 is turned off. Specifically, when the electromagnetic clutch 10 is turned off, the driving force of the movable scroll 16 for revolution around the axis 14CT of the fixed scroll 14 is no longer acting on the movable scroll 16. At the same time, as shown in FIG. 5(A), the high-pressure gas expands, and a force P2 is applied to the movable scroll 16 in the opposite direction (counterclockwise in the illustrated example) to the direction of the previous revolution. This force P2 causes the movable scroll 16 to rotate counterclockwise around its axis 16CT. However, in this embodiment, when this force P2 acts on the movable scroll 16, the small-diameter side inner wall 42b of the accommodation groove 42 collides (indirectly abuts) with the pin 38 via the ring 40, as shown in FIG. 4(C). This prevents the movable scroll 16 from rotating counterclockwise around the axis 16CT. Hereinafter, for convenience of explanation, the rotation that occurs when the rotation of the drive shaft 8 is not being transmitted (rotation in the opposite direction to the rotation that is prevented during normal operation (counterclockwise rotation in this case)) will be referred to as "reverse rotation." In other words, the rotation prevention mechanism 36 of this embodiment also includes a reverse rotation prevention mechanism. Furthermore, in the following explanation, when simply referring to "revolutionary orbital motion," it means "revolutionary orbital motion about the axis 14CT of the fixed scroll 14 (axis center of the drive shaft 8)," and when simply referring to "rotation" or "reverse rotation," it means "rotation (reverse rotation) about the axis 16CT of the movable scroll."

[0046] The rotation prevention mechanism 36 defines the maximum allowable turning radius LPOR (Fig. 4(B)) and the minimum allowable turning radius SPOR (Fig. 4(C)) of the movable scroll 16 with the above configuration. And the turning radius AOR (see Fig. 2) of the movable scroll 16 defined by the amount of eccentricity of the center 16CT of the movable scroll 16 with respect to the center 14CT of the fixed scroll 14 is set so as to satisfy the relationship SPOR < AOR < LPOR. The rotation prevention mechanism 36 of the present embodiment has the outer periphery of the pin 38 move (turn), but the turning radius thereof, that is, the distance from the central axis of the pin 38 to the central axis of the accommodation groove 42, is equivalent to the turning radius AOR of the movable scroll 16 (Fig. 4(A)).

[0047] The maximum allowable turning radius LPOR of the movable scroll 16 (rotation prevention mechanism 36) shown in Fig. 4(B) takes into account the deviation amount (axial deviation amount) from the normal eccentricity amount of the centers 14CT and 16CT of both scrolls 14 and 16 caused by the manufacture and assembly of the fixed scroll 14 and the movable scroll 16. When the tolerance of this axial deviation amount is β, the relationship AOR + β ≤ LPOR is satisfied.

[0048] Also, the minimum allowable turning radius SPOR shown in Fig. 4(C) is set to ensure a clearance amount in case foreign matter gets caught between the spiral walls 14b and 16b during the orbiting turning motion of the movable scroll 16 or there is hydraulic compression. For this reason, the minimum allowable turning radius SPOR is set with a slight clearance with respect to the turning radius AOR of the movable scroll 16 defined by the contact between the spiral wall 14b of the fixed scroll 14 and the spiral wall 16b of the movable scroll 16. When this clearance amount is γ, SPOR ≤ AOR - γ. The clearance amount γ on the minimum allowable turning radius SPOR side of the turning radius AOR of the movable scroll 16 is, for example, 0.15 mm or less.

[0049] Furthermore, in this embodiment, assuming the above-described relationships between the maximum allowable turning radius LPOR, turning radius AOR, and minimum allowable turning radius SPOR, as shown in FIG. 3B, a dimensional difference A (resulting in a minute gap G1) is ensured between the pin 38 and the ring 40, and a dimensional difference B (resulting in a minute gap G2) is ensured between the ring 40 and the small-diameter side inner wall 42b of the accommodation groove 42. This improves sliding properties during the rotation prevention operation and the counter-rotation prevention operation, and suppresses wear and deterioration of the accommodation groove 42. Note that, because the ring 40 moves relative to the pin 38 and the small-diameter side inner wall 42b, the states of the minute gaps G1 and G2 in FIG. 2C are an example of a certain timing.

[0050] More specifically, the ring 40 has a predetermined thickness i (the length (width) of the sliding surface 40c in the radial direction of the ring 40). The thickness i is the difference between the outer diameter k, which is the diameter of the outer peripheral surface 40a of the ring 40, and the inner diameter j, which is the diameter of the inner peripheral surface 40b of the ring 40.

[0051] The outer diameter k of the ring 40 is smaller than the groove width h of the storage groove 42, and a dimensional difference B (resulting in a minute gap G2) is secured between the two. The groove width h of the storage groove 42 is the distance between the larger diameter side inner wall 42a and the smaller diameter side inner wall 42b of the storage groove 42 in the radial direction of the substantially annular storage groove 42.

[0052] The outer diameter (diameter) l of the pin 38 is smaller than the inner diameter j of the ring 40, and a dimensional difference A (resulting in a minute gap G1) is secured between the two.

[0053] In this embodiment, the dimensional difference A is smaller than the dimensional difference B. As an example, the dimensional difference A is 0.005 mm or more, and the sum of the dimensional difference A and the dimensional difference B is 0.35 mm or more.

[0054] According to this rotation-preventing mechanism 36, when the movable scroll 16 makes an orbital motion during normal operation (operation due to rotation of the drive shaft 8), the large-diameter side inner wall 42a of the accommodation groove 42 collides with the pin 38 via the ring 40, preventing the rotation of the movable scroll 16. Furthermore, the outer peripheral surface 40a of the ring 40 is able to slide or roll relative to the large-diameter side inner wall 42a of the accommodation groove 42, and the inner peripheral surface 40b of the ring 40 is able to slide or roll relative to the pin 38, which can relatively increase the sliding or rolling properties of the pin 38, the ring 40, and the accommodation groove 42, and suppress wear and deterioration of the accommodation groove 42.

[0055] When preventing reverse rotation, the small-diameter side inner wall 42b of the accommodation groove 42 collides with the pin 38 via the ring 40, preventing reverse rotation of the movable scroll 16. In this case, the outer peripheral surface 40a of the ring 40 is able to slide or roll relative to the small-diameter side inner wall 42b of the accommodation groove 42, and the inner peripheral surface 40b of the ring 40 is able to slide or roll relative to the pin 38, which can relatively increase the sliding or rolling properties of the pin 38, the ring 40, and the accommodation groove 42, and suppress wear and deterioration of the accommodation groove 42.

[0056] In the rotation-preventing mechanism 36 of this embodiment, the contact area between the ring 40 and the accommodation groove 42 that accommodates it is smaller than in a conventional pin-and-disk type rotation-preventing mechanism. However, by providing a dimensional difference A between the ring 40 and the pin 38 and a dimensional difference B between the ring 40 and the accommodation groove 42, the ring 40 can slide or roll relative to the pin 38 and the accommodation groove 42, which makes it possible to reduce the PV value compared to a conventional pin-and-disk type rotation-preventing mechanism. This allows for a wider range of materials to be selected, and reduces the manufacturing costs of the compressor 1.

[0057] Furthermore, when preventing rotation (counter-rotation), by providing a ring 40 that can slide or roll against the pin 38 and the accommodating groove 42, wear on the accommodating groove 42, which has relatively low wear resistance, can be suppressed, thereby improving the wear resistance of the rotation prevention mechanism 36 as a whole.

[0058] Furthermore, by making the dimensional difference B larger than the dimensional difference A, assembly can be performed more easily. The pin 38 and the ring 40 are both separate components from the movable scroll 16, and the clearance fit between them is relatively easy to assemble even if the dimensional difference A is small. The dimensional difference A also represents the amount of play, and if it is larger than necessary, it can cause noise during rotation prevention and counter-rotation prevention. However, since multiple accommodation grooves 42 (four in this example) are drilled in one movable scroll 16, variations in the machining precision between the accommodation grooves 42 are unavoidable. Furthermore, each accommodation groove 42 must be assembled to accommodate a pin 38 fixed to the front casing 4.

[0059] Therefore, in this embodiment, the dimensional difference A is set to the minimum necessary amount, and the dimensional difference B is set to be larger than the dimensional difference A. This prevents the pin 38 and the ring 40 from coming apart after being engaged when manufacturing the compressor 1, improving the ease of assembly when attaching the movable scroll 16 to the front casing 4. It also reduces wear on the accommodation groove 42, improving the wear resistance of the rotation-preventing mechanism 36 and suppressing the generation of abnormal noise. Furthermore, because the member that can slide or roll on the pin 38 and accommodation groove 42 is constituted by the simple ring 40, it is possible to avoid an increase in parts costs.

[0060] Furthermore, since the ring 40 has a smaller volume than a conventional disk, it is possible to reduce the weight of the rotation-preventing mechanism 36. Since there is no significant increase in weight or imbalance in the movable scroll 16 that houses the ring 40, it is possible to reduce the weight of the compressor 1.

[0061] Second Embodiment A rotation-preventing mechanism 36 according to a second embodiment of the present invention will be described with reference to Figures 6 and 7. Figure 6(A) is a diagram showing an outline of the scroll unit 6 (substrate 16a side), and is a plan view viewed from the direction of line VV in Figure 1. Figure 6(B) is a plan view showing one set of rotation-preventing mechanisms 36, and Figure 6(C) is a cross-sectional view taken along line YY in Figure 6(B). Figure 7(A) is a plan view corresponding to Figure 6(A), and Figures 7(B) and (C) are plan views of one set of rotation-preventing mechanisms 36.

[0062] In the rotation-preventing mechanism 36 of the second embodiment, the ring 40 has a larger diameter than that of the first embodiment, and the pin 38 and the small-diameter inner wall 42b of the accommodating groove 42 are arranged inside the ring 40. Below, the differences from the first embodiment will be mainly described, and detailed description of the same matters (configurations) as the first embodiment will be omitted.

[0063] The ring 40 is accommodated in the accommodation groove 42 so that its outer surface 40a faces the large-diameter side inner wall 42a of the accommodation groove 42, and a portion of it is engaged (loosely fitted) between the pin 38 (its outer surface 38b) and the large-diameter side inner wall 42a of the accommodation groove 42.

[0064] As a result, the inner peripheral surface 40b of the ring 40 can slide or roll relative to the outer peripheral surface 38b of the pin 38 as the movable scroll 16 revolves. Also, as the movable scroll 16 revolves, the outer peripheral surface 40a of the ring 40 can slide or roll relative to the large-diameter inner wall 42a of the accommodation groove 42. Also, as the movable scroll 16 revolves, each sliding surface 40c can slide against the bottom surface 42c of the accommodation groove 42 and the sliding surface 34a of the thrust plate 34, respectively.

[0065] FIG. 7 is a plan view for explaining the revolution and turning motion in the second embodiment, and is a plan view corresponding to FIG. 4 of the first embodiment. The details of the revolution and turning motion of the movable scroll 16 in the second embodiment are substantially the same as those of the first embodiment described with reference to FIG. 5. That is, although detailed illustration is omitted, during normal operation (in the case of operation by rotation of the drive shaft 8), as shown in FIG. 7(A), the axis 16CT of the movable scroll 16 revolves around the axis 14CT of the fixed scroll 14 (eccentric motion with respect to the drive shaft 8). As a result, the four sets of accommodation grooves 42 move around while engaging with the pins 38 accommodated inside them. Specifically, as shown in FIGS. 7(A) and 7(B), the large-diameter side inner wall 42a of the accommodation groove 42 indirectly contacts the pin 38 via the ring 40 and moves outward to escape, and the rotation of the movable scroll 16, for example, in the clockwise direction is blocked. In this way, the movable scroll 16 performs a revolution and turning motion.

[0066] Also, when a reverse rotation operation occurs, such as when the electromagnetic clutch 10 is turned off, the accommodation groove 42 provided in the movable scroll 16, as shown in FIGS. 7(A) and 7(C), the small-diameter side inner wall 42b of the accommodation groove 42 collides with the pin 38, and the reverse rotation is blocked. In the second embodiment, in this reverse rotation operation, it is different from the first embodiment in that the pin 38 and the small-diameter side inner wall 42b of the accommodation groove 42 directly contact (abut), and in the revolution and turning motion of the movable scroll 16, a large contact area between the accommodation groove 42 and the ring 40 can be ensured.

[0067] Also, the anti-rotation mechanism 36 of the second embodiment also defines the maximum allowable turning radius LPOR (FIG. 7(B)) and the minimum allowable turning radius SPOR (FIG. 7(C)) of the movable scroll 16 by the above configuration. And the turning radius AOR of the movable scroll 16 (anti-rotation mechanism 36) defined by the eccentricity of the center 16CT of the movable scroll 16 with respect to the center CT of the fixed scroll 14 is set to satisfy the relationship SPOR < AOR < LPOR. The turning radius of the anti-rotation mechanism 36, that is, the distance from the central axis of the pin 38 to the central axis of the accommodation groove 42, is equal to the turning radius AOR of the movable scroll 16 (FIG. 7(A)).

[0068] The maximum allowable orbiting radius LPOR of the movable scroll 16 (rotation-preventing mechanism 36) shown in Figure 7(B) satisfies the relationship AOR + β ≦ LPOR, where β is the tolerance of the deviation (misalignment) from the normal eccentricity of the centers 14CT, 16CT of the fixed scroll 14 and the movable scroll 16 that occurs during the manufacture and assembly of the fixed scroll 14 and the movable scroll 16. The minimum allowable orbiting radius SPOR shown in Figure 7(C) satisfies the relationship SPOR ≦ AOR - γ, where γ is the amount of play relative to the orbiting radius AOR of the movable scroll 16, which is determined by contact between the spiral wall 14b of the fixed scroll 14 and the spiral wall 16b of the movable scroll 16. The value of the play γ is the same as in the first embodiment.

[0069] Furthermore, in this embodiment, assuming the above-described relationships between the maximum allowable turning radius LPOR, turning radius AOR, and minimum allowable turning radius SPOR, as shown in FIG. 6B, a dimensional difference C (resulting in a minute gap G3) is ensured between (the outer peripheral surface 40a of) the ring 40 and (the large-diameter side inner wall 42a of) the accommodation groove 42, and a dimensional difference D (resulting in a minute gap G4) is ensured between the pin 38 disposed inside the ring 40 and (the small-diameter side inner wall 42b of) the accommodation groove 42. This improves sliding properties during rotation prevention and counter-rotation prevention operations, and suppresses wear and deterioration of the accommodation groove 42. Note that the ring 40 moves relative to the pin 38 and the small-diameter side inner wall 42b, and the states of the minute gaps G3 and G4 shown in FIG. 6B are an example of a certain timing.

[0070] More specifically, the ring 40 has a predetermined thickness i. The thickness i is the difference between the outer diameter k of the ring 40 and the inner diameter j of the ring 40. The outer diameter k of the ring 40 is smaller than the inner diameter (diameter) m of the large-diameter side inner wall 42a of the accommodation groove 42, and a dimensional difference C (resulting in a minute gap G3) is maintained between the outer diameter (diameter) l of the pin 38 is smaller than the groove width h of the accommodation groove 42, and a dimensional difference D (resulting in a minute gap G4) is maintained between the groove width h and the sum (l + i) of the outer diameter l of the pin 38 and the thickness i of the ring 40.

[0071] In this embodiment, the dimensional difference C is smaller than the dimensional difference D, and as an example, the dimensional difference C is 0.04 mm or more, and the dimensional difference D is 0.35 mm or more.

[0072] According to the rotation-preventing mechanism 36, when the movable scroll 16 makes an orbital motion during normal operation (operation due to rotation of the drive shaft 8), the large-diameter side inner wall 42a of the accommodation groove 42 collides with the pin 38 via the ring 40, preventing the rotation of the movable scroll 16 ( FIG. 7(B) ). Furthermore, the outer peripheral surface 40a of the ring 40 is able to slide or roll relative to the large-diameter side inner wall 42a of the accommodation groove 42, and the inner peripheral surface 40b of the ring 40 is able to slide or roll relative to the pin 38, thereby suppressing wear of the accommodation groove 42.

[0073] When the reverse rotation is prevented, the small diameter side inner wall 42b of the accommodation groove 42 collides with the pin 38, preventing the reverse rotation of the movable scroll 16 (FIG. 7(C)). In this case, the small diameter side inner wall 42b of the accommodation groove 42 is allowed to slide or roll relative to the pin 38, thereby suppressing wear of the accommodation groove 42.

[0074] Assuming that the outer diameter of the disk in a conventional pin-and-disk type rotation-preventing mechanism is equal to the outer diameter k of the ring 40 in the rotation-preventing mechanism 36 of this embodiment, and that the inner diameter of the accommodation hole in the conventional pin-and-disk type rotation-preventing mechanism is equal to the inner diameter m of the accommodation groove 42 in the rotation-preventing mechanism 36 of this embodiment, the ring 40 in the rotation-preventing mechanism 36 of this embodiment can slide or roll relative to both the accommodation groove 42 and the pin 38, thereby making it possible to reduce the PV value compared to the conventional pin-and-disk type rotation-preventing mechanism. This allows for a wider range of materials to be selected, and reduces the manufacturing costs of the compressor 1.

[0075] Furthermore, in the configuration of the second embodiment, assuming that the sizes of the accommodating groove 42 and the pin 38 are equivalent to those of the configuration of the first embodiment, the opposing area (slidable area, contact area) between the outer peripheral surface 40a of the ring 40 and the large-diameter side inner wall 42a of the accommodating groove 42 can be increased compared to the first embodiment, and the PV value between the outer peripheral surface 40a of the ring 40 and the accommodating groove 42 can be reduced more than in the configuration of the first embodiment. In other words, wear and deterioration of the accommodating groove 42 in particular can be prevented more effectively than in the configuration of the first embodiment, and the wear resistance of the rotation-preventing mechanism 36 can be improved.

[0076] Furthermore, in the configuration of the second embodiment, when preventing reverse rotation, the pin 38 and the housing groove 42 come into direct contact, but the opportunities to prevent reverse rotation are relatively fewer compared to when preventing rotation. Also, as described above, when preventing rotation, the PV value between the outer peripheral surface 40a of the ring 40 and the housing groove 42 can be reduced more than in the configuration of the first embodiment. It can be said that the second embodiment, which can reduce the PV value between the outer peripheral surface 40a of the ring 40 and the housing groove 42, which have a larger contact area, is more advantageous as a rotation-preventing mechanism 36.

[0077] Furthermore, by making the dimensional difference D larger than the dimensional difference C, the ease of assembly can be improved. That is, the pin 38 and the ring 40 are both individual parts separate from the movable scroll 16, and assembly to the movable scroll 16 (accommodation groove 42) is relatively easy even if the dimensional difference C is small. In contrast, a plurality of accommodation grooves 42 (four in this example) are drilled in one movable scroll 16, and variations in the machining accuracy between the accommodation grooves 42 are unavoidable. Furthermore, each accommodation groove 42 must be assembled to accommodate a pin 38 fixed to the front casing 4.

[0078] Therefore, in this embodiment, the dimensional difference D is set to be larger than the dimensional difference C. This improves the ease of assembly when attaching the movable scroll 16 to the front casing 4. It also reduces wear on the accommodation groove 42, improving the wear resistance of the rotation-preventing mechanism 36. Furthermore, because the member that can slide or roll with respect to the pin 38 and accommodation groove 42 is constituted by the simple ring 40, it is possible to avoid an increase in parts costs.

[0079] Furthermore, since the ring 40 has a smaller volume than a conventional disk, it is possible to reduce the weight of the rotation-preventing mechanism 36. Since there is no significant increase in weight or imbalance in the movable scroll 16 that houses the ring 40, it is possible to reduce the weight of the compressor 1.

[0080] <Third embodiment> A rotation-preventing mechanism 36 according to a third embodiment of the present invention will be described with reference to Figures 8 and 9. Figure 8(A) is a diagram showing an outline of the scroll unit 6 (substrate 16a side), and is a plan view viewed from the direction of line VV in Figure 1. Figure 8(B) is a plan view showing one set of rotation-preventing mechanisms 36, and Figure 8(C) is a cross-sectional view taken along line ZZ in Figure 8(B). Figure 9(A) is a plan view corresponding to Figure 8(A), and Figures 9(B) and (C) are plan views of one set of rotation-preventing mechanisms 36.

[0081] In the rotation-preventing mechanism 36 of the third embodiment, the ring 40 has a larger diameter than that of the first embodiment, and the pin 38 and the small-diameter side inner wall 42b of the accommodating groove 42 are arranged inside the ring 40. Furthermore, the rotation-preventing mechanism 36 of the third embodiment has a center ring 41 arranged inside the ring 40. The outer peripheral surface 41a of the center ring 41 can abut against the outer peripheral surface 38b of the pin 38, and the inner peripheral surface 41b of the center ring 41 surrounds the small-diameter side inner wall 42b of the accommodating groove 42.

[0082] The following mainly describes the differences from the first or second embodiment, and a detailed description of the same matters (configurations) as the first or second embodiment will be omitted.

[0083] The ring 40 is accommodated in the accommodation groove 42 so that its outer surface 40a faces the large-diameter side inner wall 42a of the accommodation groove 42, and a portion of it is engaged (loosely fitted) between the pin 38 (its outer surface 38b) and the large-diameter side inner wall 42a of the accommodation groove 42.

[0084] The center ring 41 is engaged (loosely fitted) around the small diameter side inner wall 42b of the accommodation groove 42 so that the inner circumferential surface 41b thereof faces the small diameter side inner wall 42b of the accommodation groove 42.

[0085] As a result, the inner peripheral surface 40b of the ring 40 can slide or roll relative to the outer peripheral surface 38b of the pin 38 as the movable scroll 16 revolves. Also, as the movable scroll 16 revolves, the outer peripheral surface 40a of the ring 40 can slide or roll relative to the large-diameter side inner wall 42a of the accommodation groove 42. Also, as the movable scroll 16 revolves, each sliding surface 40c can slide against the bottom surface 42c of the accommodation groove 42 and the sliding surface 34a of the thrust plate 34, respectively. Furthermore, the center ring 41 can slide or roll relative to the small-diameter side inner wall 42b of the accommodation groove 42.

[0086] FIG. 9 is a plan view illustrating the orbital motion of the movable scroll 16 in the third embodiment, corresponding to FIG. 4 of the first embodiment. The details of the orbital motion of the movable scroll 16 in the third embodiment are generally similar to those of the first embodiment described with reference to FIG. 5. Specifically, although detailed illustration is omitted, during normal operation (when the drive shaft 8 rotates), as shown in FIG. 9(A), the axis 16CT of the movable scroll 16 orbits around the axis 14CT of the fixed scroll 14 (moves eccentrically with respect to the drive shaft 8). As a result, the four sets of accommodation grooves 42 engage with and move around the pins 38 accommodated inside the respective sets of accommodation grooves 42. Specifically, as shown in FIGS. 9(A) and 9(B), the large-diameter inner walls 42a of the accommodation grooves 42 indirectly contact the pins 38 via the rings 40, moving outward, and preventing the movable scroll 16 from rotating on its axis in, for example, a clockwise direction. In this manner, the movable scroll 16 performs orbital motion.

[0087] Also, when a reverse rotation operation occurs, such as when the electromagnetic clutch 10 is turned off, the accommodation groove 42 provided in the movable scroll 16 has its inner wall 42b on the small-diameter side of the accommodation groove 42 collide (indirectly contact) with the pin 38 via the central ring 41 as shown in FIGS. 9(A) and 9(C), thereby preventing reverse rotation. In the third embodiment, the ring 40 interposed between the accommodation groove 42 and the pin 38 when a rotation operation occurs and the central ring 41 interposed between the accommodation groove 42 and the pin 38 when a reverse rotation operation occurs are separate bodies, and the contact area between the accommodation groove 42 and the ring 40 can be ensured to be large during the revolution and rotation movement of the movable scroll 16, which is different from the first embodiment.

[0088] The rotation prevention mechanism 36 of the third embodiment also defines the maximum allowable turning radius LPOR (FIG. 9(B)) and the minimum allowable turning radius SPOR (FIG. 9(C)) of the movable scroll 16 by the above configuration. The turning radius AOR of the movable scroll 16 (rotation prevention mechanism 36) defined by the eccentricity of the center 16CT of the movable scroll 16 with respect to the center 14CT of the fixed scroll 14 is set so as to satisfy the relationship SPOR < AOR < LPOR.

[0089] The maximum allowable turning radius LPOR of the movable scroll 16 (rotation prevention mechanism 36) satisfies the relationship AOR + β ≤ LPOR when the tolerance of the deviation amount (shaft misalignment amount) from the normal eccentricity of the centers 14CT and 16CT of the two scrolls 14 and 16 is β. Also, the minimum allowable turning radius SPOR is set to SPOR ≤ AOR - γ when the play amount with respect to the turning radius AOR of the movable scroll 16 is γ. The value of the play amount γ is the same as that in the first embodiment.

[0090] Furthermore, in this embodiment, assuming the above-described relationships between the maximum allowable turning radius LPOR, the turning radius AOR, and the minimum allowable turning radius SPOR, as shown in FIG. 8B, a dimensional difference H (resulting in a minute gap G5) is ensured between (the outer peripheral surface 40a of) the ring 40 and (the large-diameter-side inner wall 42a of) the accommodation groove 42, a dimensional difference E (resulting in a minute gap G6) is ensured between (the outer peripheral surface 41a of) the pin 38 disposed inside the ring 40 and (the small-diameter-side inner wall 42b of) the center ring 41, and a dimensional difference F (resulting in a minute gap G7) is ensured between (the small-diameter-side inner wall 42b of the accommodation groove 42 and the inner peripheral surface 41b of the center ring 41. Note that the ring 40 and the center ring 41 move relative to the pin 38 and the accommodation groove 42, respectively, and the states of the minute gaps G5, G6, and G7 shown in FIG. 8B are examples of certain timings.

[0091] More specifically, the ring 40 has a predetermined thickness i, and the center ring 41 has a predetermined thickness p. The outer diameter k of the ring 40 is smaller than the inner diameter (diameter) m of the large-diameter side inner wall 42a of the accommodation groove 42, thereby ensuring a dimensional difference H (thereby leaving a minute gap G5) between them. The outer diameter (diameter) l of the pin 38 is smaller than the groove width h of the accommodation groove 42. More specifically, the sum of the outer diameter l of the pin 38, the wall thickness i of the ring 40, and the wall thickness p of the center ring 41 is smaller than the groove width h of the accommodation groove 42, thereby ensuring a dimensional difference E (thereby leaving a minute gap G6) between this sum and the groove width h. Furthermore, the inner diameter o of the center ring 41 is larger than the inner diameter (diameter) n of the small-diameter side inner wall 42b of the accommodation groove 42, thereby ensuring a dimensional difference F (thereby leaving a minute gap G7) between them.

[0092] Thus, in the third embodiment, the inner diameter n of the small-diameter side inner wall 42b of the accommodating groove 42 and the inner diameter o of the central ring 41 have a dimensional difference F (first dimensional difference), the inner diameter m of the large-diameter side inner wall of the accommodating groove 42 and the outer diameter k of the ring 40 have a dimensional difference H (second dimensional difference), and the sum (i+p+l) of the thickness i of the ring 40, the thickness p of the central ring and the outer diameter l of the pin have a dimensional difference E (third dimensional difference) from the groove width h of the accommodating groove 42, and the dimensional difference E is greater than the dimensional difference H, and the dimensional difference H is greater than the dimensional difference F.

[0093] As an example, the dimensional difference F is 0.005 mm or more, the dimensional difference H is 0.04 mm or more, and the dimensional difference E is 0.35 mm or more.

[0094] According to the rotation-preventing mechanism 36, when the movable scroll 16 makes an orbital motion during normal operation (operation due to rotation of the drive shaft 8), the large-diameter side inner wall 42a of the accommodation groove 42 collides with the pin 38 via the ring 40, preventing the rotation of the movable scroll 16 ( FIG. 9(B) ). Furthermore, the outer peripheral surface 40a of the ring 40 is able to slide or roll relative to the large-diameter side inner wall 42a of the accommodation groove 42, and the inner peripheral surface 40b of the ring 40 is able to slide or roll relative to the pin 38, thereby suppressing wear of the accommodation groove 42.

[0095] When preventing reverse rotation, the small-diameter side inner wall 42b of the accommodation groove 42 collides with the pin 38 via the center ring 41, preventing reverse rotation of the movable scroll 16 (FIG. 9(C)). In this case, the center ring 41 is allowed to slide or roll relative to the pin 38 and the small-diameter side inner wall 42b of the accommodation groove 42, thereby suppressing wear of the accommodation groove 42.

[0096] Assuming that the outer diameter of the disk in a conventional pin-and-disk type rotation-preventing mechanism is equal to the outer diameter k of the ring 40 in the rotation-preventing mechanism 36 of this embodiment, and that the inner diameter of the accommodation hole in the conventional pin-and-disk type rotation-preventing mechanism is equal to the inner diameter m of the accommodation groove 42 in the rotation-preventing mechanism 36 of this embodiment, the ring 40 in the rotation-preventing mechanism 36 of this embodiment can slide or roll relative to both the accommodation groove 42 and the pin 38, thereby making it possible to reduce the PV value compared to the conventional pin-and-disk type rotation-preventing mechanism. This allows for a wider range of materials to be selected, and reduces the manufacturing costs of the compressor 1.

[0097] Furthermore, in the configuration of the third embodiment, assuming that the size of the accommodating groove 42 is the same as in the configuration of the first embodiment, the opposing area (slidable area, contact area) between the outer surface 40a of the ring 40 and the large diameter side inner wall 42a of the accommodating groove 42 can be increased compared to the first embodiment, and the PV value between the outer surface 40a of the ring 40 and the accommodating groove 42 can be reduced compared to the configuration of the first embodiment.

[0098] Furthermore, during the counter-rotation operation, the center ring 41 prevents direct contact between the pin 38 and the small-diameter inner wall 42b of the accommodating groove 42. In other words, wear and deterioration of the accommodating groove 42 in particular can be prevented more effectively than in the configuration of the first embodiment, and the wear resistance of the rotation-preventing mechanism 36 can be improved.

[0099] Furthermore, by satisfying the relationship of dimensional difference F<dimensional difference H<dimensional difference E, assembly is easier and noise can be prevented. In other words, the pin 38, ring 40, and center ring 41 are all individual parts separate from the movable scroll 16. The clearance fit between the center ring 41 and the accommodation groove 42 (the inner wall 42b on the small diameter side) is relatively easy to assemble even if the dimensional difference F is small. Furthermore, the dimensional difference F is also the amount of play, and if it is larger than necessary, it can cause noise when preventing reverse rotation. Furthermore, assembly of the ring 40 to the movable scroll 16 (accommodation groove 42) is relatively easy even if the dimensional difference H is small.

[0100] In contrast, a plurality of accommodation grooves 42 (four in this example) are formed in one orbiting scroll 16, and variations in machining accuracy between the accommodation grooves 42 are unavoidable. Furthermore, each accommodation groove 42 must be assembled to accommodate a pin 38 fixed to the front casing 4.

[0101] Therefore, in this embodiment, the dimensional difference F is set to the minimum necessary amount, the dimensional difference H is set to be larger than the dimensional difference F, and the dimensional difference E is set to be larger than the dimensional difference H. This makes it possible to prevent the center ring 41 from coming off the accommodating groove 42 after being engaged with it, and to prevent abnormal noise from being generated when the center ring 41 collides with the accommodating groove 42, during manufacturing of the compressor 1. It also improves the ease of assembly when attaching the movable scroll 16 to the front casing 4. It also makes it possible to suppress wear on the accommodating groove 42 and improve the wear resistance of the rotation-preventing mechanism 36. Furthermore, because the members that can slide or roll relative to the pin 38 and the accommodating groove 42 are composed of the simple ring 40 and center ring 41, it is possible to avoid an increase in parts costs.

[0102] Furthermore, since the ring 40 and the central ring 41 have a smaller volume than conventional disks, the weight of the rotation prevention mechanism 36 can be reduced, and there is no excessive increase in weight or imbalance in the movable scroll 16, so the weight of the compressor 1 can be reduced.

[0103] In the above embodiment, the minimum values ​​of the dimensional differences A, B, C, D, E, F, and H are exemplified, but these are only examples, and the numbers are not limited to the above examples as long as the dimensional differences A, B, C, D, E, F, and H between the above-mentioned parts can be ensured. Furthermore, the dimensional differences A, B, C, D, E, F, and H may be set as a ratio to the turning radius AOR.

[0104] It is also possible to form the accommodation groove 42 in the rotation-preventing mechanism 36 on the front casing 4 side, and fix the pin 38 on the movable scroll 16 side. In this case, however, the length (height) of the protruding portion 38a of the pin 38 needs to be shorter than the thickness of the base plate 16a of the movable scroll 16, which poses a risk of the pin 38 falling out. Therefore, it is preferable to form the accommodation groove 42 on the movable scroll 16 side, and fix the pin 38 on the front casing 4 side, as in this embodiment.

[0105] In addition, in the above-described embodiments, an engine-driven scroll compressor 1 incorporated in a vehicle air conditioning system has been described. However, the present invention is applicable to all scroll-type fluid machines, such as an integrated electric motor-driven scroll compressor and compressors or expanders in various fields that use various working fluids. In the case of an expander, the volume of the fluid pocket 18 increases as the fluid pocket 18 moves from the center toward the outer end of the spiral walls 14b, 16b, and the fluid taken into the fluid pocket 18 from the center side of the spiral walls 14b, 16b expands.

[0106] The heating device of the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention. [Industrial Applicability]

[0107] The present invention can be used in the field of scroll-type fluid machinery. [Explanation of symbols]

[0108] 1 Scroll-type fluid machinery (compressor) 2 Rear casing 2a end wall 4 Front casing (casing) 4a Base 4b End wall 6 Scroll Unit 8 drive shaft 8a Eccentric bushing 8b Large diameter shaft 10 Electromagnetic clutch 12 Drive pulley 14 Fixed Scroll 14a Substrate 14b Spiral Wall 16 movable scroll 16a board 16b Spiral Wall 16c back 18 Fluid pocket (compression chamber) 20 Suction chamber 22 Discharge chamber 24 Discharge hole 28 Stopper plate 30 Reinforcement part (boss) 34 Thrust plate 34a Sliding surface 36 Anti-rotation mechanism 38 Anti-rotation pin (pin) 38a Protrusion 38b Outer surface 40 Rings 40a Outer surface 40b Inner surface 40c sliding surface 41 Central Ring 41a Outer surface 41b Inner surface 42 Storage groove 42a Large diameter side inner wall 42b Small diameter side inner wall

Claims

1. A scroll-type fluid machine equipped with a rotation prevention mechanism that prevents rotation of a movable scroll without interfering with the orbital movement of the movable scroll relative to a fixed scroll fixed to a casing, The rotation prevention mechanism includes: a substantially annular accommodation groove formed in a base plate on which the spiral wall of the movable scroll is erected, the groove having a central axis parallel to the axis of revolution of the orbital motion; a pin fixed to a base portion of the casing and projecting into the accommodation groove so that the revolution axis and its central axis are parallel; a ring that is accommodated in the accommodation groove, the outer circumferential surface of which is slidable or rollable relative to the large-diameter side inner wall of the accommodation groove, and the inner circumferential surface of which is slidable or rollable relative to the pin; a difference in size between the outer diameter of the pin and the inner diameter of the ring is smaller than a difference in size between the outer diameter of the ring and the groove width of the receiving groove; A scroll-type fluid machine characterized by:

2. The pin has a cylindrical shape, and an inner peripheral surface thereof is capable of sliding or rolling relative to an outer peripheral surface of the pin.

2. The scroll-type fluid machine according to claim 1.

3. The pin is disposed inside the ring, The outer diameter of the ring is set to be smaller than the groove width of the accommodation groove.

3. The scroll-type fluid machine according to claim 1 or 2.

4. The pin and the small diameter side inner wall of the accommodation groove are disposed inside the ring.

3. The scroll-type fluid machine according to claim 1 or 2.

5. The dimensional difference between the inner diameter of the large diameter side inner wall of the accommodation groove and the outer diameter of the ring is the difference between the sum of the thickness of the ring and the outer diameter of the pin and the width of the receiving groove; 5. The scroll type fluid machine according to claim 4.

6. a central ring disposed inside the ring, the central ring having an outer circumferential surface capable of contacting an outer circumferential surface of the pin and an inner circumferential surface surrounding the small diameter side inner wall of the accommodation groove; an inner diameter of the small-diameter side inner wall of the accommodation groove and an inner diameter of the center ring have a first dimensional difference; an inner diameter of the large-diameter side inner wall of the accommodation groove and an outer diameter of the ring have a second dimensional difference; a third dimensional difference between the sum of the wall thickness of the ring, the wall thickness of the center ring, and the outer diameter of the pin and the groove width of the receiving groove; the third dimensional difference is greater than the second dimensional difference, and the second dimensional difference is greater than the first dimensional difference; 5. The scroll type fluid machine according to claim 4.

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