Sliding parts

Abstract

The present invention provides a sliding component capable of reducing the frictional resistance of a sliding surface accompanying eccentric rotation. The sliding component (7) is annular and has a sliding surface (7a) that slides relatively with eccentric rotation, wherein a plurality of grooves (70) that are not connected to any space (20, 50) on the inner diameter side or the outer diameter side are provided along the circumferential direction on the sliding surface (7a).

Description

Technical Field

[0001] The present invention relates to a sliding component for a rotary machine including an eccentric mechanism. Background Art

[0002] In the past, as a rotating machine including an eccentric mechanism, for example, a scroll compressor used in an automobile air-conditioning system is a mechanism as follows: it has a scroll compression mechanism and an eccentric mechanism, and the scroll compression mechanism is composed of a fixed scroll disk having a spiral vortex on the surface of an end plate and a movable scroll disk having a spiral vortex on the surface of the end plate. The eccentric mechanism causes the rotating shaft to rotate eccentrically, and the movable scroll disk slides relative to the fixed scroll disk along with the eccentric rotation through the rotation of the rotating shaft, thereby pressurizing the refrigerant supplied from the low-pressure chamber on the outer diameter side of the two scroll disks, and causing the high-pressure refrigerant to be discharged from the discharge hole formed in the center of the fixed scroll disk (see patent document 1).

[0003] The scroll compressor disclosed in Patent Document 1 also includes a back-pressure supply mechanism that supplies a portion of the refrigerant compressed by the scroll compression mechanism to a back-pressure chamber. This back-pressure chamber is formed on the back side of the thrust plate, which bears the axial load of the movable scroll. The back pressure acting on the back side of the movable scroll presses the movable scroll toward the fixed scroll. This reduces axial refrigerant leakage between the two scrolls and improves the compression efficiency of the scroll compressor.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-61208 (pp. 5-6, Figure 1 ) Summary of the Invention

[0007] Problems to be solved by the invention

[0008] In the scroll compressor disclosed in Patent Document 1, a sealing ring is interposed between the thrust plate and the housing. This allows the thrust plate to be moved axially while preventing back pressure from leaking from the back-pressure chamber, thereby pressing the movable scroll toward the fixed scroll via the thrust plate. However, since the thrust plate's sliding surface is pressed against the back surface of the movable scroll, frictional resistance on the sliding surface is high, potentially affecting the movement of the movable scroll.

[0009] The present invention has been made in view of such problems, and an object of the present invention is to provide a sliding component capable of reducing frictional resistance of a sliding surface accompanying eccentric rotation.

[0010] Means for solving problems

[0011] In order to solve the above problems, the sliding component of the present invention is:

[0012] It is annular in shape and has a sliding surface that slides relative to the eccentric rotation.

[0013] A plurality of grooves that are not communicated with any of the spaces on the inner diameter side and the outer diameter side are provided along the circumferential direction on the sliding surface.

[0014] As a result, the fluid can flow from the external space into the grooves through the sliding surfaces by utilizing the dynamic pressure generated in the grooves provided on the sliding surfaces that slide relative to each other accompanying the eccentric rotation, and the fluid retained in the grooves is not easy to flow out from between the sliding surfaces to the external space. Dynamic pressure can be generated over the entire circumference between the sliding surfaces in accordance with the direction of relative movement of the grooves accompanying the eccentric rotation, thereby slightly separating the sliding surfaces from each other and forming a fluid film, thereby improving the lubricity between the sliding surfaces and reducing the frictional resistance of the sliding surfaces.

[0015] The groove may be formed in a circular shape.

[0016] Thus, dynamic pressure can be stably generated in any direction of relative movement of the groove accompanying eccentric rotation, and thus pressure can be evenly distributed over the entire circumference between the sliding surfaces.

[0017] Alternatively, the groove may have a geometric center at the radial center of the sliding surface.

[0018] As a result, the radial dimension of the sliding member can be reduced, and a sliding member with low sliding resistance can be provided.

[0019] The sliding member may be a sliding member having a narrower radial width among a pair of sliding members that slide relative to each other.

[0020] Thus, dynamic pressure can be reliably generated through the grooves between the sliding surfaces that slide relative to each other due to eccentricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 1 is a schematic structural diagram showing a scroll compressor to which a side seal as a sliding member according to an embodiment of the present invention is applied;

[0022] Figure 2 is a diagram showing a sliding surface of a side seal according to an embodiment of the present invention;

[0023] Figure 3 These diagrams illustrate the relative sliding movement of the sliding surface of the side seal and the sliding surface of the thrust plate in an embodiment of the present invention. Furthermore, the diagrams illustrate the positional relationship between the sliding surface of the side seal and the sliding surface of the thrust plate when the rotation shaft is eccentrically rotated to (b) 90 degrees, (c) 180 degrees, and (d) 270 degrees, starting from (a).

[0024] Figure 4 It is a diagram showing a modified example of the groove formed on the sliding surface of the side seal. DETAILED DESCRIPTION

[0025] Hereinafter, modes for implementing the sliding member of the present invention will be described based on examples.

[0026] Example

[0027] Reference Figures 1 to 3 For the sake of convenience, in the drawings, grooves and the like formed on the sliding surface of the sliding member are indicated by dots.

[0028] The sliding component of the present invention is applied to a scroll compressor C that sucks, compresses, and discharges a refrigerant as a fluid, such as a rotary machine including an eccentric mechanism, and is used in an air conditioning system of an automobile, etc. In this embodiment, the refrigerant is a gas mixed with mist-like lubricating oil.

[0029] First, the scroll compressor C will be described. Figure 1 As shown, the scroll compressor C is mainly composed of a housing 1, a rotating shaft 2, an inner shell 3, a scroll compression mechanism 4, a side seal 7 as a sliding member, a thrust plate 8 and a drive motor M.

[0030] The housing 1 consists of a cylindrical outer shell 11 and a cover 12 that closes one opening of the outer shell 11. Within the outer shell 11 are formed a low-pressure chamber 20, into which low-pressure refrigerant is supplied from a refrigerant circuit (not shown) through the suction port 10; a high-pressure chamber 30, into which high-pressure refrigerant compressed by the scroll compression mechanism 4 is discharged; and a back-pressure chamber 50, into which a portion of the refrigerant compressed by the scroll compression mechanism 4 is supplied along with lubricating oil. Furthermore, the back-pressure chamber 50 is formed within the cylindrical inner shell 3 housed within the outer shell 11.

[0031] A discharge passage 13 is formed in the cover 12, connecting the refrigerant circuit (not shown) with the high-pressure chamber 30. Furthermore, a portion of a back-pressure passage 14 is formed in the cover 12, branching from the discharge passage 13 and connecting the high-pressure chamber 30 with the back-pressure chamber 50. Furthermore, an oil separator 6 is provided in the discharge passage 13 to separate lubricating oil from the refrigerant.

[0032] The inner casing 3 is fixed with one axial end abutting against the end plate 41a of the fixed scroll 41 that constitutes the scroll compression mechanism 4. A radially extending suction communication passage 15 is formed at one end of the inner casing 3. Specifically, the low-pressure chamber 20 is formed from the exterior of the inner casing 3 to the interior of the inner casing 3 via the suction communication passage 15. Refrigerant supplied to the interior of the inner casing 3 through the suction communication passage 15 is drawn into the scroll compression mechanism 4.

[0033] The scroll compression mechanism 4 mainly includes a fixed scroll 41 fixed to the cover 12 in a substantially sealed manner, and a movable scroll 42 accommodated in the inner casing 3 .

[0034] The fixed scroll 41 is made of metal and includes a spiral wrap 41b projecting from the surface of a circular end plate 41a, i.e., one end face of the end plate 41a. Furthermore, the fixed scroll 41 has a recessed portion 41c formed on the back side of the end plate 41a, i.e., the inner diameter of the other end face of the end plate 41a. This recessed portion 41c and the end face of the cover 12 define the high-pressure chamber 30.

[0035] The movable scroll 42 is made of metal and includes a spiral vortex 42b protruding from the surface of a circular end plate 42a, i.e., one axial end face of the end plate 42a. Furthermore, the movable scroll 42 is provided with a protrusion 42c protruding from the back face of the end plate 42a, i.e., the center of the other end face of the end plate 42a. An eccentric portion 2a formed at one end of the rotating shaft 2 is inserted into the protrusion 42c so as to be relatively rotatable. Furthermore, in this embodiment, the eccentric portion 2a of the rotating shaft 2 and the balancing weight 2b protruding radially outward from one end of the rotating shaft 2 constitute an eccentric mechanism for causing the rotating shaft 2 to rotate eccentrically.

[0036] When the rotating shaft 2 is driven by the drive motor M, the eccentric portion 2a rotates eccentrically, and the movable scroll 42 slides relative to the fixed scroll 41 in response to this eccentric rotation. At this time, the movable scroll 42 rotates eccentrically relative to the fixed scroll 41. As this rotation occurs, the contact position between the wraps 41b and 42b shifts sequentially in the direction of rotation. The compression chamber 40 formed between the wraps 41b and 42b gradually shrinks as it moves toward the center. As a result, refrigerant drawn into the compression chamber 40 from the low-pressure chamber 20 formed on the outer diameter side of the scroll compression mechanism 4 is compressed and ultimately discharged into the high-pressure chamber 30 through the discharge port 41d provided in the center of the fixed scroll 41.

[0037] Next, the side seal 7 as the sliding member in this embodiment will be described. Figure 1 and Figure 2 As shown, the side seal 7 is made of resin, has a rectangular cross-section and an annular shape when viewed in the axial direction, and is fixed to the back surface of the end plate 42a of the movable scroll 42. A sliding surface 7a is formed on one side of the side seal 7, which abuts the sliding surface 8a of the thrust plate 8.

[0038] like Figure 2 As shown, a plurality of grooves 70 are arranged at equal intervals in the circumferential direction on the sliding surface 7 a of the side seal 7 , which grooves 70 do not communicate with either the inner or outer diameter side spaces, that is, the back pressure chamber 50 or the low pressure chamber 20 .

[0039] The groove 70 is formed in a circular shape having a center P as its geometric center on an imaginary circle VC, which is the radial center of the sliding surface 7a. The radial center is an example of the average value of the inner and outer diameters of the sliding surface 7a, but it does not need to be a mathematical average value. L2, which will be described later, may be 0.5 to 2 times L3.

[0040] Specifically, the groove 70 is composed of a circular wall surface 70 a extending in the axial direction so as to be perpendicular to the flat sliding surface 7 a , and a flat bottom surface 70 b extending parallel to the sliding surface 7 a .

[0041] Furthermore, the bottom surface 70 b of the groove 70 is not limited to being formed in a flat surface extending parallel to the sliding surface 7 a , and may be formed in an inclined surface or a curved surface, for example.

[0042] Furthermore, the radius L1 of the groove 70 is larger than the radial dimension L2 of the boss portion between the inner periphery of the sliding surface 7a and the wall surface 70a (L1>L2).

[0043] Furthermore, groove 70 is formed as a circle with a single radius, with center P at the radial center of sliding surface 7a. Therefore, radial dimensions L3 and L2 of the boss portion between the outer periphery of sliding surface 7a and wall surface 70a are equal (L2 = L3). This increases the capacity for retaining fluid within groove 70 between sliding surfaces 7a and 8a.

[0044] like Figure 1 As shown, the thrust plate 8 is made of metal and has an annular shape. A seal ring 43 is fixed to one end surface of the thrust plate 8, and the seal ring 43 abuts against the inner circumferential surface of the inner housing 3. As a result, the thrust plate 8 functions as a thrust bearing that receives the axial load of the movable scroll 42 via the side seal 7.

[0045] Furthermore, the side seal 7 and the seal ring 43 define the interior of the inner casing 3 as a low-pressure chamber 20, formed on the outer diameter side of the movable scroll 42, and a back-pressure chamber 50, formed on the back side of the movable scroll 42. The back-pressure chamber 50 is sealed against the rotating shaft 2, which is inserted through the through-hole 3a, by a seal ring 44 fixed to the inner circumference of a through-hole 3a provided at the center of the other end of the inner casing 3, thereby forming a sealed space. Furthermore, a throttle orifice (not shown) is provided in the back-pressure communication passage 14, which spans the cover 12, the fixed scroll 41, and the inner casing 3 and connects the high-pressure chamber 30 and the back-pressure chamber 50. The refrigerant in the high-pressure chamber 30, which has been decompressed and adjusted by the throttle orifice, is supplied to the back-pressure chamber 50 along with the lubricating oil separated by the oil separator 6. At this time, the pressure within the back-pressure chamber 50 is adjusted to be higher than that within the low-pressure chamber 20. The inner housing 3 is provided with a pressure relief hole 16 that penetrates radially and connects the low pressure chamber 20 and the back pressure chamber 50. A pressure regulating valve 45 is provided in the pressure relief hole 16. The pressure regulating valve 45 opens when the pressure in the back pressure chamber 50 exceeds a set value.

[0046] Furthermore, the projection 42c of the movable scroll 42 is inserted into the through hole 8b in the center of the thrust plate 8. The through hole 8b is formed to a diameter large enough to allow the eccentric rotation of the eccentric portion 2a of the rotating shaft 2 inserted into the projection 42c. That is, the sliding surface 7a of the side seal 7 can slide relative to the sliding surface 8a of the thrust plate 8 in accordance with the eccentric rotation of the rotating shaft 2 (see FIG. Figure 3 ).

[0047] In addition, Figure 3 middle, Figure 3 (a) to (d) show the rotation of the fixed scroll 41 (see Figure 1 ) side view of the protrusion 42c of the rotation trajectory, the protrusion 42c with Figure 3 (a) shows the state where the reference is rotated 90 degrees, 180 degrees, and 270 degrees clockwise, respectively. The sliding areas of the sliding surface 7a of the side seal 7 and the sliding surface 8a of the thrust plate 8 are schematically indicated by circles. For ease of explanation, only the eccentric portion 2a of the rotating shaft 2, which is inserted into the protrusion 42c, is shown; the balancing weight 2b and other components that constitute the eccentric mechanism are not shown.

[0048] Thus, the side seal 7 is a sliding component having a sliding surface 7a that slides relative to the sliding surface 8a of the thrust plate 8 as it rotates eccentrically. Multiple grooves 70 are circumferentially provided on the sliding surface 7a of the side seal 7, each of which is disconnected from either the back-pressure chamber 50 or the low-pressure chamber 20, where fluid resides, on either the inner or outer diameter sides. Consequently, the dynamic pressure generated in the grooves provided on the sliding surface 7a as it slides relative to each other as it rotates eccentrically allows the fluid to flow from the back-pressure chamber 50 into the grooves 70 through the space between the sliding surfaces 7a and 8a. Furthermore, since the grooves 70 are disconnected from either the back-pressure chamber 50 or the low-pressure chamber 20, the fluid retained in the grooves 70 is less likely to flow out from between the sliding surfaces 7a and 8a into the low-pressure chamber 20, and the fluid is readily retained within the grooves 70. Therefore, it is not easy for the sliding surfaces 7a and 8a to become poorly lubricated. In response to the relative movement of the groove 70 accompanying the eccentric rotation, dynamic pressure can be stably generated over the entire circumference between the sliding surfaces 7a and 8a, so that the sliding surfaces 7a and 8a are slightly separated from each other and a liquid film of lubricating oil is formed, thereby improving the lubricity between the sliding surfaces 7a and 8a and reducing the friction resistance of the sliding surface 7a.

[0049] Furthermore, multiple grooves 70 are provided circumferentially, forming a circular shape. This allows for stable dynamic pressure generation within all grooves 70 in response to the relative movement of the grooves 70 accompanying the eccentric rotation, and evenly distributes the pressure across the entire circumference between the sliding surfaces 7a and 8a. Furthermore, the distribution of pressure generated within the multiple grooves 70 due to the relative movement of the grooves 70 accompanying the eccentric rotation of the rotating shaft 2 shifts approximately circumferentially with the eccentric rotation. Therefore, fluid flowing from a circumferentially upstream groove 70 into the space between the sliding surfaces 7a and 8a due to the generation of dynamic pressure easily flows into an adjacent circumferentially downstream groove 70, facilitating the formation of a roughly uniform and evenly distributed lubricating oil film across the entire circumference between the sliding surfaces 7a and 8a. Furthermore, the deviation in pressure distribution is minimized across the entire circumference between the sliding surfaces 7a and 8a, thereby suppressing surface tilt between the sliding surfaces 7a and 8a.

[0050] The groove 70 is formed so as to have a center P as a geometric center on an imaginary circle VC as the radial center of the sliding surface 7a (see Figure 2 ) is circular. Thus, the radial dimension of the sliding component can be made smaller, and a sliding component with small sliding resistance can be provided.

[0051] Furthermore, the radial dimension L1 of the groove 70 is larger than the radial dimension L2 of the boss portion between the inner periphery of the sliding surface 7a and the wall surface 70a (L1>L2). This facilitates the flow of fluid from the back pressure chamber 50 into the groove 70 through the space between the sliding surfaces 7a and 8a by dynamic pressure.

[0052] In addition, the side seal 7 having the groove 70 formed on the sliding surface 7a has a narrower radial width than the thrust plate 8 that slides relatively therewith (see FIG. Figure 1 and Figure 3 Thus, between the sliding surfaces 7a and 8a that slide relative to each other with eccentric rotation, the entire sliding surface 7a of the side seal 7 is always located within the sliding area with the sliding surface 8a of the thrust plate 8 (see Figure 3 ), and can reliably generate live pressure through the groove 70.

[0053] While the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and any changes or additions made without departing from the gist of the present invention are also encompassed by the present invention.

[0054] In the above embodiment, a method of applying the side seal 7 as a sliding component in the scroll compressor C used in the air-conditioning system of an automobile, etc. is described, but it is not limited to this. As long as it is a rotating machine including an eccentric mechanism, it can also be applied to, for example, a scroll expansion compressor that has an expander and a compressor integrated into one body.

[0055] Furthermore, the fluid existing in the spaces inside and outside the sliding surface of the sliding member may be in a gas, liquid, or a mixed state of gas and liquid.

[0056] In addition, in the above embodiment, the groove 70 is described as being circular, but the present invention is not limited to this. The groove can be formed in any shape as long as it is not connected to either the inner diameter side or the outer diameter side. For example, the groove may be formed in an elliptical or polygonal shape. In this case, as in the above embodiment, it is preferably formed in an elliptical or polygonal shape with the center P as the geometric center on the imaginary circle VC serving as the radial center of the sliding surface 7a.

[0057] Furthermore, in the above embodiment, the groove 70 formed on the sliding surface 7a of the side seal 7 is described as being circular with its center P being its geometric center on an imaginary circle VC, which is the radial center of the sliding surface 7a. However, the present invention is not limited thereto. For example, the groove 70 may be formed as a circle with its center located closer to the high-pressure side than the radial center of the sliding surface. This facilitates the flow of fluid from the high-pressure side space through the space between the sliding surfaces into the groove by utilizing dynamic pressure.

[0058] In addition, if Figure 4 As in the side seal 107 of the illustrated modification, the grooves 170 are formed into circular shapes having centers on the inner diameter side and the outer diameter side of the sliding surface 107 a , respectively. Thus, a plurality of grooves 170 may be provided in a staggered pattern in the circumferential direction.

[0059] Furthermore, in the above embodiment, the side seal 7 is described as having a low-pressure chamber 20 formed on the outer diameter side of the sliding surface 7a and a back-pressure chamber 50 formed on the inner diameter side, which has a higher pressure than the low-pressure chamber. However, this is not limiting. The side seal 7 can also be used in environments where the outer diameter side of the sliding surface 7a is high pressure and the inner diameter side is low pressure. Furthermore, the sliding component of the present invention only needs to have a sliding surface that slides relative to each other with eccentric rotation. It is not limited to environments with a pressure difference between the inside and outside of the sliding surface; it can also be used in environments where the pressure inside and outside the sliding surface is approximately the same. Furthermore, the sliding component of the present invention does not need to function as a seal; it only needs to be able to reduce friction on the sliding surface.

[0060] In the above embodiment, the side seal 7 having the sliding surfaces 7a and 8a that slide relative to each other is made of resin, and the thrust plate 8 is made of metal. However, the material of the sliding members can be freely selected according to the use environment.

[0061] In the above embodiment, the groove 70 is formed on the sliding surface 7a of the side seal 7. However, the invention is not limited thereto. A groove may be formed in the sliding area of ​​the sliding surface 8a of the thrust plate 8 as a sliding member having a sliding surface that slides relatively with eccentric rotation (see FIG. Figure 3 ) In addition, grooves may be formed on both the sliding surface 7 a of the side seal 7 and the sliding surface 8 a of the thrust plate 8 .

[0062] Furthermore, in the above embodiment, the sliding surface 7a of the side seal 7 and the sliding surface 8a of the thrust plate 8, which serve as sliding components, are described as sliding relative to each other with eccentric rotation. However, this is not limiting. Alternatively, only one of the side seal and the thrust plate may be provided, and grooves may be formed on the sliding surface that slides relative to each other with eccentric rotation. For example, in the case of only the thrust plate, grooves may be formed on either or both of the sliding surface of the thrust plate and the back surface of the movable scroll end plate. Alternatively, in the case of only the side seal, grooves may be formed on the sliding surface of the side seal. In this case, the side seal also contacts the inner circumferential surface of the inner casing, functioning as a thrust bearing that bears the axial load of the movable scroll.

[0063] In addition, in the case where there is no side seal and thrust plate, and the back surface of the end plate of the movable scroll abuts the inner peripheral surface of the inner casing to act as a thrust bearing that bears the axial load of the movable scroll, a groove can also be formed on the sliding surface formed on the back surface of the end plate of the movable scroll.

[0064] Explanation of symbols

[0065] 1: Housing; 2: Rotating shaft; 2a: Eccentric portion; 3: Inner casing; 4: Scroll compression mechanism; 6: Oil separator; 7: Side seal (sliding component); 7a: Sliding surface; 8: Thrust plate; 8a: Sliding surface; 10: Suction port; 13: Discharge communication passage; 14: Back-pressure communication passage; 15: Suction communication passage; 20: Low-pressure chamber; 30: High-pressure chamber; 40: Compression chamber; 41: Fixed scroll; 42: Movable scroll; 50: Back-pressure chamber; 70: Groove; 70a: Wall surface; 70b: Bottom surface; 107: Side seal (sliding component); 107a: Sliding surface; 170: Groove; C: Scroll compressor; M: Drive motor; P: Center.

Claims

1. An eccentric sliding assembly comprising: The first sliding member has a sliding surface, The second sliding member has a sliding surface, an eccentric mechanism configured to cause the sliding surface of the first sliding member to slide with the sliding surface of the second sliding member so that, in a plan view, the center of the first sliding member imaginarily describes a circle that is eccentric relative to the center of the second sliding member; The sliding surface of at least one of the first sliding component and the second sliding component is provided with a plurality of grooves which are not connected to any space on the inner diameter side or the outer diameter side along the circumferential direction. One of the spaces on the inner diameter side and the outer diameter side is a high-pressure side, and the other one of the spaces on the inner diameter side and the outer diameter side is a low-pressure side. The groove is formed into a circle having a single radius and having a center at the radial center of the sliding surface of at least one of the first sliding member and the second sliding member; The radial dimension (L1) of the groove is larger than the radial dimension (L2) of the boss portion between the groove and the high-pressure side periphery of the sliding surface of one of the first sliding component and the second sliding component; A radial dimension (L2) of the boss portion between the groove and the periphery of the high-pressure side of the sliding surface is equal to a radial dimension (L3) of the boss portion between the groove and the periphery of the low-pressure side of the sliding surface.

2. The eccentric sliding assembly according to claim 1, wherein: The groove has a geometric center at a radial center of at least one of the first sliding member and the second sliding member.

3. The eccentric sliding assembly according to claim 1 or 2, wherein: A radial width of one of the sliding surface of the first sliding member and the sliding surface of the second sliding member is smaller than a radial width of the remaining one of the sliding surface of the first sliding member and the sliding surface of the second sliding member.

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