Sliding parts

Abstract

Provided is a sliding component that can stably reduce friction resistance between sliding surfaces in conjunction with eccentric rotation.　This sliding component 8 has a sliding surface 8a that undergoes relative sliding in conjunction with eccentric rotation, wherein the sliding surface 8a is provided with a plurality of dynamic pressure generation grooves 80 in the circumferential direction, said dynamic pressure generation grooves extending in a tapered manner toward the downstream side in the direction of eccentric rotation relative to an opposing sliding surface 7a.

Description

Technical Field

[0001] The present invention relates to a sliding component used in a rotating machine including an eccentric mechanism.

Background Art

[0002] Machines with rotational drive used in various industrial fields include not only rotating machines in which the central axis rotates while being held in a fixed position, but also rotating machines in which the central axis rotates eccentrically. One example of a rotating machine with eccentric rotation is a scroll compressor. This type of compressor includes a fixed scroll having a spiral wrap on the surface of an end plate, a movable scroll having a spiral wrap on the surface of an end plate, a scroll compression mechanism, an eccentric mechanism for eccentrically rotating a rotating shaft, etc. By relatively sliding the movable scroll while causing it to eccentrically rotate with respect to the fixed scroll by the rotation of the rotating shaft, the fluid supplied from the low-pressure chamber on the outer diameter side of both scrolls is pressurized, and a high-pressure fluid is discharged from a discharge hole formed at the center of the fixed scroll.

[0003] These scroll compressors that utilize a mechanism for relatively sliding the movable scroll while causing it to eccentrically rotate with respect to the fixed scroll are not only highly efficient in compression but also have low noise, and thus are widely used in various applications such as refrigeration cycles. However, there has been a problem such as refrigerant leakage from the axial gap between the two scrolls. The scroll compressor shown in Patent Document 1 includes a thrust plate that relatively slides with the movable scroll on the back side of the movable scroll, and a part of the refrigerant compressed by the scroll compression mechanism is supplied to a back pressure chamber formed on the back side of this thrust plate. By pressing the movable scroll toward the fixed scroll, refrigerant leakage from the axial gap between the two scrolls during refrigerant compression can be reduced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] However, in the scroll compressor disclosed in Patent Document 1, since a part of the refrigerant compressed by the scroll compression mechanism is used to press the movable scroll from the back side toward the fixed scroll via the thrust plate, although the refrigerant leakage from the axial clearance between the two scrolls can be reduced, on the sliding surface involving eccentric rotation between the two scrolls, particularly between the movable scroll and the thrust plate, pressing forces act from both axial sides, resulting in a large frictional resistance, which inhibits the smooth operation of the movable scroll and cannot improve the compression efficiency.

[0006] The present invention has been made paying attention to such problems, and an object thereof is to provide a sliding part capable of stably reducing the frictional resistance between sliding surfaces involving eccentric rotation.

MEANS FOR SOLVING THE PROBLEMS

[0007] In order to solve the above problems, the sliding part of the present invention is a sliding part having a sliding surface that relatively slides with eccentric rotation, wherein a plurality of dynamic pressure generating grooves that taper and extend in the circumferential direction are provided on the sliding surface on the downstream side in the relative eccentric rotation direction with respect to the opposing sliding surface. According to this, when the opposing sliding surface relatively slides with eccentric rotation with respect to the sliding surface, the fluid in the dynamic pressure generating groove is collected in the tapered part having a tapered shape toward the downstream side in the relative eccentric rotation direction between the sliding surface and the opposing sliding surface in the dynamic pressure generating groove, and dynamic pressure can be surely generated at the part on the downstream side in the relative eccentric rotation direction of the dynamic pressure generating groove. According to this, the lubricity is improved by separating the sliding surfaces, and the frictional resistance between the sliding surfaces can be reduced.

[0008] The downstream end of the dynamic pressure generating groove in the eccentric rotation direction may be an acute-angled corner portion. According to this, the fluid in the dynamic pressure generating groove is collected at the acute-angled corner portion, and a large dynamic pressure can be generated at the corner portion.

[0009] The dynamic pressure generating groove may communicate with the external space of the sliding surface. According to this, since the fluid can be introduced into the dynamic pressure generating groove from the external space, the dynamic pressure can be surely generated in the dynamic pressure generating groove.

[0010] The sliding surface and the opposing sliding surface may relatively slide with eccentric rotation such that the opposing sliding surface overlaps with some of the plurality of dynamic pressure generating grooves and does not overlap with other dynamic pressure generating grooves. According to this, in the relative sliding with eccentric rotation between the sliding surface and the opposing sliding surface, among the plurality of dynamic pressure generating grooves arranged in the circumferential direction of the sliding surface, no dynamic pressure is generated in the other dynamic pressure generating grooves where the opposing sliding surface does not overlap, and dynamic pressure is generated only in some of the dynamic pressure generating grooves where the opposing sliding surface overlaps. According to this, it is possible to prevent the occurrence of an unintended negative pressure in other dynamic pressure generating grooves.

[0011] On at least one of the inner diameter side and the outer diameter side of the sliding surface, a plurality of the dynamic pressure generating grooves are provided in the circumferential direction, and on at least the other of the inner diameter side and the outer diameter side of the sliding surface, a plurality of other dynamic pressure generating grooves that taper and extend toward the downstream side in the relative eccentric rotation direction with respect to the opposing sliding surface are provided in the circumferential direction. According to this, it becomes possible to generate dynamic pressure by the respective dynamic pressure generating grooves on the outer diameter side and the inner diameter side of the sliding surface.

[0012] The tapered portions of the dynamic pressure generating grooves adjacent in the radial direction and the tapered portions of the other dynamic pressure generating grooves may be formed to face in opposite directions in the eccentric rotation direction. According to this, since dynamic pressure can be generated by the tapered portions of the dynamic pressure generating grooves adjacent in the radial direction and the tapered portions of the other dynamic pressure generating grooves, the sliding surfaces are separated while suppressing inclination.

[0013] The dynamic pressure generating groove and the other dynamic pressure generating groove are separated in the radial direction, and this separation width may be larger than the radial width of the annular opposing sliding surface that slides relative to the sliding surface. According to this, since the annular opposing sliding surface is not arranged across the dynamic pressure generating groove adjacent in the radial direction and the other dynamic pressure generating groove, it is possible to prevent the simultaneous generation of positive pressure and negative pressure in the dynamic pressure generating groove adjacent in the radial direction and the other dynamic pressure generating groove.

[0014] A plurality of non-communication grooves surrounded by a land that partitions the dynamic pressure generating groove and the other dynamic pressure generating groove may be provided in the circumferential direction between the dynamic pressure generating groove and the other dynamic pressure generating groove. According to this, the eccentrically rotating opposing sliding surface overlaps with either the dynamic pressure generating groove, the other dynamic pressure generating groove, or the non-communication groove in the circumferential direction. Therefore, regardless of the relative position between the sliding surface and the opposing sliding surface, dynamic pressure is generated in the circumferential direction between the sliding surfaces.

[0015] A plurality of the non-communication grooves are arranged in the radial direction between the dynamic pressure generating groove adjacent in the radial direction and the other dynamic pressure generating groove, and each non-communication groove may have a different shape. According to this, it is possible to change the dynamic pressure generated according to the relative position between the sliding surface and the opposing sliding surface.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Mode for Carrying Out the Invention

[0017] A mode for carrying out the sliding component according to the present invention will be described below based on examples.

Example

[0018] The sliding component according to Example 1 will be described with reference to FIGS. 1 to 6. For convenience of explanation, in the drawings, dots are attached to grooves and the like formed on the sliding surface of the sliding component.

[0019] The sliding component of the present invention is applied to a scroll compressor C that sucks, compresses, and discharges a refrigerant as a fluid used in a rotating machine including an eccentric mechanism, such as an air conditioning system of an automobile or the like. In this embodiment, the refrigerant is a gas and is in a state mixed with mist-like lubricating oil.

[0020] First, the scroll compressor C will be described. As shown in FIG. 1, the scroll compressor C mainly includes a housing 1, a rotating shaft 2, an inner casing 3, a scroll compression mechanism 4, a side seal 7, a thrust plate 8 as a sliding component, and a drive motor M.

[0021] The housing 1 is composed of a cylindrical casing 11 and a cover 12. The cover 12 is configured to close the opening of the casing 11. Further, the opening on the opposite side of the axis direction to the opening closed by the cover 12 in the casing 11 is closed by the drive motor M.

[0022] Inside the casing 11, a low-pressure chamber 20, a high-pressure chamber 30, and a back-pressure chamber 50 are formed. The low-pressure chamber 20 as an external space on the low-pressure side is supplied with low-pressure refrigerant from a refrigerant circuit (not shown) through an inlet 10. The high-pressure chamber 30 discharges the high-pressure refrigerant compressed by the scroll compression mechanism 4. The back-pressure chamber 50 as an external space on the high-pressure side is supplied with a part of the refrigerant compressed by the scroll compression mechanism 4 together with lubricating oil. Incidentally, the back-pressure chamber 50 is formed inside a cylindrical inner casing 3 housed inside the casing 11.

[0023] A discharge communication passage 13 is formed in the cover 12. The discharge communication passage 13 communicates the refrigerant circuit (not shown) with the high-pressure chamber 30. Further, a part of a back-pressure communication passage 14 that communicates the high-pressure chamber 30 and the back-pressure chamber 50 branches off from the discharge communication passage 13 and is formed. Incidentally, an oil separator 6 for separating lubricating oil from the refrigerant is provided in the discharge communication passage 13.

[0024] The inner casing 3 is fixed in a state where its axial end is in contact with the end plate 41a of the fixed scroll 41 that constitutes the scroll compression mechanism 4. Further, a suction communication passage 15 that penetrates in the radial direction is formed in the side wall of the inner casing 3. That is, the low-pressure chamber 20 is formed from the outside of the inner casing 3 to the inside of the inner casing 3 through the suction communication passage 15. The refrigerant supplied to the inside of the inner casing 3 through the suction communication passage 15 is sucked into the scroll compression mechanism 4.

[0025] The scroll compression mechanism 4 is mainly composed of a fixed scroll 41 and a movable scroll 42. The fixed scroll 41 is fixed to the cover 12 in a substantially sealed state. The movable scroll 42 is housed inside the inner casing 3.

[0026] The fixed scroll 41 is made of metal and has a spiral wrap 41b. The spiral wrap 41b projects from the surface of the disk-shaped end plate 41a, that is, toward the movable scroll 42 from the end plate 41a. Further, a recess 41c is formed in the fixed scroll 41 on the back surface of the end plate 41a, that is, on the inner diameter side of the end face of the end plate 41a that contacts the cover 12 and is recessed in the direction opposite to the cover 12. The high-pressure chamber 30 is defined by this recess 41c and the cover 12.

[0027] The movable scroll 42 is made of metal and has a spiral wrap 42b. The spiral wrap 42b projects from the surface of the disk-shaped end plate 42a, that is, toward the fixed scroll 41 from the end plate 42a. Further, a boss 42c that projects from the center of the back surface of the end plate 42a is formed on the movable scroll 42. An eccentric portion 2a formed on the rotating shaft 2 is inserted into the boss 42c so as to be relatively rotatable. In this embodiment, an eccentric mechanism for eccentrically rotating the rotating shaft 2 is constituted by the eccentric portion 2a of the rotating shaft 2 and a counterweight portion 2b that projects in the outer diameter direction from the rotating shaft 2.

[0028] When the rotating shaft 2 is rotationally driven by the drive motor M, the eccentric portion 2a rotates eccentrically, and the movable scroll 42 relatively slides with eccentric rotation while maintaining its posture with respect to the fixed scroll 41. At this time, the movable scroll 42 eccentrically rotates with respect to the fixed scroll 41, and with this rotation, the contact positions of the laps 41b and 42b sequentially move in the rotational direction, and the compression chamber 40 formed between the laps 41b and 42b gradually shrinks while moving toward the center. As a result, the refrigerant sucked from the low-pressure chamber 20 formed on the outer diameter side of the scroll compression mechanism 4 into the compression chamber 40 is compressed, and finally, the high-pressure refrigerant is discharged into the high-pressure chamber 30 through the discharge hole 41d provided at the center of the fixed scroll 41.

[0029] Next, the side seal 7 will be described. The side seal 7 is made of resin and has a rectangular cross-section and an annular shape in the axial direction view (see Fig. 4). Further, the side seal 7 is fixed to the back surface of the end plate 42a of the movable scroll 42.

[0030] The side seal 7 has a sliding surface 7a as an opposing sliding surface that contacts the sliding surface 8a of the thrust plate 8, and the sliding surface 7a is formed as a flat surface on which irregularities and the like are not formed.

[0031] Next, the thrust plate 8 as a sliding component in this embodiment will be described. In Fig. 3(b), for convenience of explanation, a state in which the A-A cross-sectional view is linearly developed is shown.

[0032] Referring to Figs. 2 and 3, the thrust plate 8 is made of metal and has an annular shape. The thrust plate 8 is formed with a sliding surface 8a that contacts the sliding surface 7a (see Fig. 1) of the side seal 7.

[0033] As shown in Fig. 2, the sliding surface 8a of the thrust plate 8 includes an outer hydrodynamic groove 80, an inner hydrodynamic groove 81, and a land 82. The outer hydrodynamic groove 80 as a hydrodynamic groove is provided in plurality (15 in this embodiment) on the outer diameter side of the sliding surface 8a. The inner hydrodynamic groove 81 as another hydrodynamic groove is provided in plurality (15 in this embodiment) on the inner diameter side of the sliding surface 8a. The land 82 partitions the outer hydrodynamic groove 80 and the inner hydrodynamic groove 81.

[0034] The outer hydrodynamic groove 80 extends while inclining in the circumferential direction from the outer diameter edge of the sliding surface 8a toward the inner diameter side. Further, the outer hydrodynamic groove 80 communicates with the low-pressure chamber 20 (see Fig. 1) as an external space on the outer diameter side.

[0035] Specifically, the outer hydrodynamic groove 80 is partitioned by side walls 80a, 80b, an inner end wall 80c, and a bottom wall 80d. The side walls 80a, 80b extend in the depth direction orthogonally to the flat surface 82a of the land 82, and extend while inclining in the circumferential direction from the outer diameter edge of the sliding surface 8a toward the inner diameter side in the counterclockwise direction. The inner end wall 80c connects the inner diameter ends of the side walls 80a, 80b. The bottom wall 80d extends parallel to the surface 82a and connects the depth direction ends of the side walls 80a, 80b and the inner end wall 80c.

[0036] The inner end wall 80c is shorter than the side walls 80a, 80b and extends substantially along the circumferential direction. Further, the inner end wall 80c has a smaller component of inclination in the circumferential direction than the side walls 80a, 80b.

[0037] Further, the corner 80e formed by the side wall 80a and the inner end wall 80c forms an acute angle, and the corner 80f formed by the side wall 80b and the inner end wall 80c forms an obtuse angle.

[0038] That is, the outer dynamic pressure generating groove 80 tapers and extends in the counterclockwise direction. In other words, the corner 80e functions as the tapered portion of the outer dynamic pressure generating groove 80. Note that tapering in the counterclockwise direction (i.e., the downstream side in the eccentric rotation direction) means that the angle formed by the two side walls (i.e., the two side walls facing the eccentric rotation direction among the side walls of each groove, that is, the two side walls facing the circumferential component and the radial component in the eccentric rotation direction in any state) facing the eccentric rotation direction is less than 180°. The presence of an angle less than 180° allows the fluid to gather and generate dynamic pressure. Furthermore, when the corner is an acute angle, it becomes difficult for the fluid to leak out of the groove, and it is possible to efficiently generate dynamic pressure.

[0039] On the other hand, the inner dynamic pressure generating groove 81 extends while inclining in the circumferential direction from the inner diameter edge of the sliding surface 8a toward the outer diameter side. Also, the inner dynamic pressure generating groove 81 communicates with the back pressure chamber 50 (see FIG. 1) as the external space on the inner diameter side.

[0040] Specifically, the inner dynamic pressure generating groove 81 is defined by side walls 81a, 81b, an outer end wall 81c, and a bottom wall 81d. The side walls 81a, 81b extend in the depth direction perpendicular to the flat surface 82a of the land 82. Also, the side walls 81a, 81b extend while inclining in the circumferential direction from the inner diameter edge of the sliding surface 8a toward the outer diameter side in the clockwise direction. The outer end wall 81c connects the outer diameter ends of the side walls 81a, 81b. The bottom wall 81d extends parallel to the surface 82a and connects the depth direction ends of the side walls 81a, 81b and the outer end wall 81c.

[0041] The outer end wall 81c is shorter than the side walls 81a, 81b and extends substantially along the circumferential direction. Also, the component of the outer end wall 81c that inclines is smaller than that of the side walls 81a, 81b. Further, the corner 81e formed by the side wall 81a and the outer end wall 81c forms an acute angle, and the corner 81f formed by the side wall 81b and the outer end wall 81c forms an obtuse angle.

[0042] That is, the inner dynamic pressure generating groove 81 extends taperingly in the clockwise direction. In other words, the angled portion 81e forming an acute angle functions as the tapered portion of the inner dynamic pressure generating groove 81, and the tapered portion of the outer dynamic pressure generating groove 80 and the tapered portion of the inner dynamic pressure generating groove 81 face in opposite directions in the circumferential direction.

[0043] As shown in FIGS. 3(a) and 3(b), the width dimension L1 of the outer dynamic pressure generating groove 80 (i.e., the separation width between the side walls 80a and 80b) is formed to be larger than the depth dimension L2 of the outer dynamic pressure generating groove 80 (L1 > L2). Here, the width dimension of the opening of the outer dynamic pressure generating groove 80 is illustrated as the width dimension L1 of the outer dynamic pressure generating groove 80.

[0044] Also, the width dimension L3 of the inner dynamic pressure generating groove 81 (i.e., the separation width between the side walls 81a and 81b) is formed to be larger than the depth dimension L4 of the inner dynamic pressure generating groove 81 (L3 > L4). Here, the width dimension of the opening of the inner dynamic pressure generating groove 81 is illustrated as the width dimension L3 of the inner dynamic pressure generating groove 81.

[0045] As long as the width dimensions of the outer dynamic pressure generating groove 80 and the inner dynamic pressure generating groove 81 are formed to be larger than the depth dimensions, the width dimensions and depth dimensions of the outer dynamic pressure generating groove 80 and the inner dynamic pressure generating groove 81 can be freely changed, but it is preferable that the width dimensions L1 and L3 are 10 times or more the depth dimensions L2 and L4. Furthermore, the width dimensions L1 and L3 may be the same or different. Also, the depth dimensions L2 and L4 may be the same or different.

[0046] Also, the inner end wall 80c of the outer dynamic pressure generating groove 80 and the outer end wall 81c of the inner dynamic pressure generating groove 81 are separated in the radial direction, and the radial separation width L5 between the outer dynamic pressure generating groove 80 and the inner dynamic pressure generating groove 81 is formed to be larger than the radial width L6 of the sliding surface 7a of the side seal 7 (L5 > L6).

[0047] Referring to FIG. 1, a seal ring 43 is fixed to this thrust plate 8. The seal ring 43 is in contact with the inner peripheral surface of the inner casing 3 on the surface opposite to the sliding surface 8a in the axial direction. Thereby, the thrust plate 8 functions as a thrust bearing that receives the axial load of the movable scroll 42 via the side seal 7.

[0048] Also, the side seal 7 and the seal ring 43 partition 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 inside the inner casing 3. The back-pressure chamber 50 is a sealed space formed between the inner casing 3 and the rotating shaft 2. The seal ring 44 is fixed to the inner periphery of a through-hole 3a provided at the center of the other end of the inner casing 3 and is in sealing sliding contact with the rotating shaft 2 inserted through the through-hole 3a. Further, a back-pressure communication passage 14 that communicates the high-pressure chamber 30 and the back-pressure chamber 50 is formed across the cover 12, the fixed scroll 41, and the inner casing 3. Also, an orifice (not shown) is provided in the back-pressure communication passage 14, and the refrigerant in the high-pressure chamber 30 whose pressure has been reduced and adjusted by the orifice is supplied to the back-pressure chamber 50 together with the lubricating oil separated by the oil separator 6. At this time, the pressure in the back-pressure chamber 50 is adjusted to be higher than the pressure in the low-pressure chamber 20. Incidentally, a pressure relief hole 16 that penetrates radially and communicates the low-pressure chamber 20 and the back-pressure chamber 50 is formed in the inner casing 3. Also, a pressure regulating valve 45 is provided in the pressure relief hole 16. The pressure regulating valve 45 is configured to open when the pressure in the back-pressure chamber 50 exceeds the set value.

[0049] Also, a boss 42c of the movable scroll 42 is inserted into a through-hole 8b at the center of the thrust plate 8. The through-hole 8b is formed to have a diameter that can allow eccentric rotation by the eccentric portion 2a of the rotating shaft 2 inserted into the boss 42c. That is, the sliding surface 7a of the side seal 7 can relatively slide with eccentric rotation with respect to the sliding surface 8a of the thrust plate 8 due to the eccentric rotation of the rotating shaft 2 (see FIG. 4).

[0050] In addition, in FIG. 4, FIGS. 4(a) to 4(d) show the states in which the boss 42c has rotated 90 degrees, 180 degrees, and 270 degrees counterclockwise, respectively, with respect to FIG. 4(a) among the rotation trajectories of the boss 42c when viewed from the fixed scroll 41 side. Also, the sliding region between the sliding surface 7a of the side seal 7 and the sliding surface 8a of the thrust plate 8 is schematically shown by dots. For the sake of convenience in explanation, regarding the rotating shaft 2, only the eccentric portion 2a inserted into the boss 42c is shown in the figure, and the illustration of the counterweight portion 2b and the like constituting the eccentric mechanism is omitted.

[0051] As described above, the thrust plate 8 is a sliding component having a sliding surface 8a that relatively slides with respect to the eccentric rotation of the sliding surface 7a of the side seal 7.

[0052] In addition, hereinafter, when the thrust plate 8 is regarded as an analog clock, the position directly above the paper surface is defined as the 12 o'clock position. A plurality of outer dynamic pressure generating grooves near 12 o'clock on the sliding surface 8a are referred to as outer dynamic pressure generating grooves 80A, a plurality of outer dynamic pressure generating grooves near 3 o'clock are referred to as outer dynamic pressure generating grooves 80B, a plurality of outer dynamic pressure generating grooves near 6 o'clock are referred to as outer dynamic pressure generating grooves 80C, and a plurality of outer dynamic pressure generating grooves near 9 o'clock are referred to as outer dynamic pressure generating grooves 80D. Also, a plurality of inner dynamic pressure generating grooves near 12 o'clock on the sliding surface 8a are referred to as inner dynamic pressure generating grooves 81A, a plurality of inner dynamic pressure generating grooves near 3 o'clock are referred to as inner dynamic pressure generating grooves 81B, a plurality of inner dynamic pressure generating grooves near 6 o'clock are referred to as inner dynamic pressure generating grooves 81C, and a plurality of inner dynamic pressure generating grooves near 9 o'clock are referred to as inner dynamic pressure generating grooves 81D.

[0053] Specifically, in the state of FIG. 4(a), in the portion of the sliding surface 8a near 10 o'clock to 2 o'clock, the sliding surface 7a overlaps with a plurality of outer dynamic pressure generating grooves 80A. In the portion of the sliding surface 8a near 3 o'clock, the sliding surface 7a does not overlap with the outer dynamic pressure generating groove 80B and the inner dynamic pressure generating groove 81B, and is disposed on the land 82 between the outer dynamic pressure generating groove 80B and the inner dynamic pressure generating groove 81B. In the portion of the sliding surface 8a near 4 o'clock to 8 o'clock, the sliding surface 7a overlaps with a plurality of inner dynamic pressure generating grooves 81C. In the portion of the sliding surface 8a near 9 o'clock, the sliding surface 7a does not overlap with the outer dynamic pressure generating groove 80D and the inner dynamic pressure generating groove 81D, and is disposed on the land 82 between the outer dynamic pressure generating groove 80D and the inner dynamic pressure generating groove 81D.

[0054] That is, in the state of FIG. 4(a), the sliding surface 7a overlaps with a part of the outer dynamic pressure generating grooves 80A and does not overlap with the other outer dynamic pressure generating grooves 80B to 80D. Further, the sliding surface 7a overlaps with a part of the inner dynamic pressure generating grooves 81C and does not overlap with the other inner dynamic pressure generating grooves 81A, 81B, and 81D.

[0055] Also, in the state of FIG. 4(b), at the portion near 12 o'clock on the sliding surface 8a, the sliding surface 7a does not overlap with the outer dynamic pressure generating groove 80A and the inner dynamic pressure generating groove 81A, and is disposed on the land 82 between the outer dynamic pressure generating groove 80A and the inner dynamic pressure generating groove 81A. At the portion near 1 o'clock to 5 o'clock on the sliding surface 8a, the sliding surface 7a overlaps with a plurality of inner dynamic pressure generating grooves 81B. At the portion near 6 o'clock on the sliding surface 8a, the sliding surface 7a does not overlap with the outer dynamic pressure generating groove 80C and the inner dynamic pressure generating groove 81C, and is disposed on the land 82 between the outer dynamic pressure generating groove 80C and the inner dynamic pressure generating groove 81C. At the portion near 7 o'clock to 11 o'clock on the sliding surface 8a, the sliding surface 7a overlaps with a plurality of outer dynamic pressure generating grooves 80D.

[0056] That is, in the state of FIG. 4(b), the sliding surface 7a overlaps with a part of the outer dynamic pressure generating grooves 80D and does not overlap with the other outer dynamic pressure generating grooves 80A to 80C. Further, the sliding surface 7a overlaps with a part of the inner dynamic pressure generating grooves 81B and does not overlap with the other inner dynamic pressure generating grooves 81A, 81C, and 81D.

[0057] Also, in the state of FIG. 4(c), at the portion near 10 o'clock to 2 o'clock on the sliding surface 8a, the sliding surface 7a overlaps with a plurality of inner dynamic pressure generating grooves 81A. At the portion near 3 o'clock on the sliding surface 8a, the sliding surface 7a does not overlap with the outer dynamic pressure generating groove 80B and the inner dynamic pressure generating groove 81B, and is disposed on the land 82 between the outer dynamic pressure generating groove 80B and the inner dynamic pressure generating groove 81B. At the portion near 4 o'clock to 8 o'clock on the sliding surface 8a, the sliding surface 7a overlaps with a plurality of outer dynamic pressure generating grooves 80C. At the portion near 9 o'clock on the sliding surface 8a, the sliding surface 7a does not overlap with the outer dynamic pressure generating groove 80D and the inner dynamic pressure generating groove 81D, and is disposed on the land 82 between the outer dynamic pressure generating groove 80D and the inner dynamic pressure generating groove 81D.

[0058] That is, in the state of FIG. 4(c), the sliding surface 7a overlaps with a part of the outer dynamic pressure generating grooves 80C and does not overlap with the other outer dynamic pressure generating grooves 80A, 80B, and 80D. Further, the sliding surface 7a overlaps with a part of the inner dynamic pressure generating grooves 81A and does not overlap with the other inner dynamic pressure generating grooves 81B to 81D.

[0059] Also, in the state of FIG. 4(d), at the portion near 12 o'clock on the sliding surface 8a, the sliding surface 7a does not overlap with the outer dynamic pressure generating groove 80A and the inner dynamic pressure generating groove 81A, and is disposed on the land 82 between the outer dynamic pressure generating groove 80A and the inner dynamic pressure generating groove 81A. At the portion near 1 to 5 o'clock on the sliding surface 8a, the sliding surface 7a overlaps with a plurality of outer dynamic pressure generating grooves 80B. At the portion near 6 o'clock on the sliding surface 8a, the sliding surface 7a does not overlap with the outer dynamic pressure generating groove 80C and the inner dynamic pressure generating groove 81C, and is disposed on the land 82 between the outer dynamic pressure generating groove 80C and the inner dynamic pressure generating groove 81C. At the portion near 7 to 11 o'clock on the sliding surface 8a, the sliding surface 7a overlaps with a plurality of inner dynamic pressure generating grooves 81A.

[0060] That is, in the state of FIG. 4(d), the sliding surface 7a overlaps with a part of the outer dynamic pressure generating grooves 80B and does not overlap with the other outer dynamic pressure generating grooves 80A, 80C, and 80D. Further, the sliding surface 7a overlaps with a part of the inner dynamic pressure generating grooves 81D and does not overlap with the other inner dynamic pressure generating grooves 81A to 81C.

[0061] Thus, according to the eccentric rotation angle of the sliding surface 7a, the positions of the outer dynamic pressure generating grooves 80A to 80D and the inner dynamic pressure generating grooves 81A to 81D with which the sliding surface 7a overlaps move continuously on the sliding surface 8a.

[0062] Next, the generation of hydrodynamic pressure during the relative sliding between the thrust plate 8 and the side seal 7 will be described with reference to FIGS. 5 and 6. In FIG. 5, the mode when the side seal 7 moves from the state of FIG. 4(a) to the state of FIG. 4(b) is shown, and in FIG. 6, the mode when the side seal 7 moves from the state of FIG. 4(c) to the state of FIG. 4(d) is shown. Also, in FIGS. 5 and 6, the thrust plate 8 as viewed from the fixed scroll 41 side is illustrated, and the circular marks shown in the enlarged portions indicate the locations where the pressure becomes high in the external hydrodynamic pressure generating grooves 80 and the internal hydrodynamic pressure generating grooves 81.

[0063] As shown in FIG. 5, when the side seal 7 moves in the direction of the white arrow, hydrodynamic pressure is generated in the plurality of external hydrodynamic pressure generating grooves 80A and the plurality of internal hydrodynamic pressure generating grooves 81C.

[0064] Specifically, when the side seal 7 moves in the direction of the white arrow, the fluid in the external hydrodynamic pressure generating groove 80A moves following the white arrow direction, that is, the eccentric rotation direction of the sliding surface 7a, and is collected at the acute-angled corner 80e, and a large hydrodynamic pressure is generated at the corner 80e. Similarly, in the internal hydrodynamic pressure generating groove 81C, the fluid in the internal hydrodynamic pressure generating groove 81C moves following the white arrow direction and is collected at the acute-angled corner 81e, and a large hydrodynamic pressure is generated at the corner 81e.

[0065] In this way, large hydrodynamic pressure is generated at the corner 80e of the external hydrodynamic pressure generating groove 80A and the corner 81e of the internal hydrodynamic pressure generating groove 81C, and the sliding surfaces 7a and 8a can be separated from each other. Therefore, a fluid film is formed between the sliding surfaces 7a and 8a by the fluid, and the frictional resistance between the sliding surfaces 7a and 8a can be reduced.

[0066] Further, when the fluid in the external hydrodynamic pressure generating groove 80A and the internal hydrodynamic pressure generating groove 81C moves following the eccentric rotation direction of the sliding surface 7a, the fluid in the low-pressure chamber 20 is introduced into the external hydrodynamic pressure generating groove 80A through the outer diameter side opening of the external hydrodynamic pressure generating groove 80A, and the fluid in the back-pressure chamber 50 is introduced into the internal hydrodynamic pressure generating groove 81C through the inner diameter side opening of the internal hydrodynamic pressure generating groove 81C.

[0067] Thus, since the fluid can be introduced from the low-pressure chamber 20 and the back-pressure chamber 50 into the outer dynamic pressure generating grooves 80A and the inner dynamic pressure generating grooves 81C, the dynamic pressure can be surely generated in the outer dynamic pressure generating grooves 80A and the inner dynamic pressure generating grooves 81C.

[0068] Further, since the sliding surface 7a overlaps with some of the outer dynamic pressure generating grooves 80A and does not overlap with the other outer dynamic pressure generating grooves 80B to 80D, it is possible to prevent the occurrence of unintended dynamic pressure (negative pressure) in the outer dynamic pressure generating grooves 80B to 80D where the sliding surface 7a does not overlap. Also, since the sliding surface 7a overlaps with some of the inner dynamic pressure generating grooves 81C and does not overlap with the other inner dynamic pressure generating grooves 81A, 81B, 81D, it is possible to prevent the occurrence of unintended dynamic pressure (negative pressure) in the inner dynamic pressure generating grooves 81A, 81B, 81D where the sliding surface 7a does not overlap.

[0069] Also, the corners 80e of each outer dynamic pressure generating groove 80 and the corners 81e of the inner dynamic pressure generating groove 81 face in opposite directions in the circumferential direction. In other words, the corners 80e of the outer dynamic pressure generating grooves 80 adjacent in the radial direction and the corners 81e of the inner dynamic pressure generating groove 81 face in opposite directions in the eccentric rotation direction of the sliding surface 7a. Therefore, in the state of FIG. 5, the corners 80e of the outer dynamic pressure generating groove 80A at the position around 10 o'clock to 2 o'clock on the sliding surface 8a and the corners 81e of the inner dynamic pressure generating groove 81C at the position around 10 o'clock to 2 o'clock, that is, large dynamic pressure can be generated on both sides in the radial direction of the sliding surface 8a. Therefore, the sliding surfaces 7a and 8a can be separated from each other while suppressing the inclination of the sliding surfaces 7a and 8a.

[0070] Further, since the back-pressure chamber 50 extends to the inner diameter side of the sliding surfaces 7a and 8a, when the sliding surfaces 7a and 8a are separated from each other, the fluid in the back-pressure chamber 50 is introduced from the inner diameter side of the sliding surfaces 7a and 8a. Also, when the scroll compression mechanism 4 is driven, the pressure in the back-pressure chamber 50 becomes high, and since the high-pressure fluid is introduced from the back-pressure chamber 50 between the sliding surfaces 7a and 8a, the sliding surfaces 7a and 8a can be further separated from each other by the pressure of the fluid.

[0071] Returning to FIG. 3, since the radial separation width L5 between each outer dynamic pressure generating groove 80 and each inner dynamic pressure generating groove 81 is formed to be larger than the radial width L6 of the sliding surface 7a of the side seal 7, when the sliding surface 7a overlaps with one of the outer dynamic pressure generating groove 80 and the inner dynamic pressure generating groove 81 adjacent in the radial direction, it does not overlap with the other of the outer dynamic pressure generating groove 80 and the inner dynamic pressure generating groove 81 adjacent in the radial direction.

[0072] For example, as shown in the upper enlarged portion of FIG. 5, when the sliding surface 7a overlaps with the outer dynamic pressure generating groove 80A, it does not overlap with the inner dynamic pressure generating groove 81A adjacent thereto in the radial direction. Also, as shown in the lower enlarged portion of FIG. 5, when the sliding surface 7a overlaps with the inner dynamic pressure generating groove 81A, it does not overlap with the outer dynamic pressure generating groove 80A adjacent thereto in the radial direction.

[0073] That is, since the sliding surface 7a is not disposed across the outer dynamic pressure generating groove 80A and the inner dynamic pressure generating groove 81A adjacent in the radial direction, it is possible to prevent the simultaneous generation of positive pressure in the outer dynamic pressure generating groove 80A and negative pressure in the inner dynamic pressure generating groove 81A, and the simultaneous generation of negative pressure in the outer dynamic pressure generating groove 80C and positive pressure in the inner dynamic pressure generating groove 81C.

[0074] Also, as described above, the positions of the outer dynamic pressure generating grooves 80A to 80D and the inner dynamic pressure generating grooves 81A to 81D with which the sliding surface 7a overlaps continuously move on the sliding surface 8a according to the eccentric rotation angle of the sliding surface 7a. Therefore, regardless of the eccentric rotation angle of the sliding surface 7a, it is possible to separate the sliding surfaces 7a and 8a while suppressing the inclination of the sliding surfaces 7a and 8a over the entire circumference of the sliding surface 8a.

[0075] For example, in the state of FIG. 6, when the side seal 7 moves in the direction of the white arrow, a large dynamic pressure is generated at the corner 80e of the outer dynamic pressure generating groove 80C and the corner 81e of the inner dynamic pressure generating groove 81A, and the sliding surfaces 7a and 8a can be separated from each other while suppressing the inclination of the sliding surfaces 7a and 8a.

[0076] Next, in FIG. 5, the form when the side seal 7 moves from the state of FIG. 4(a) to the state of FIG. 4(b) was described, and in FIG. 6, the form when moving from the state of FIG. 4(c) to the state of FIG. 4(d) was described. However, since dynamic pressure is generated in substantially the same form when the side seal 7 moves from the state of FIG. 4(b) to the state of FIG. 4(c) and from the state of FIG. 4(d) to the state of FIG. 4(a), the description thereof is omitted.

Embodiment

[0077] Next, the sliding surface 108a of the thrust plate 108 according to Embodiment 2 will be described with reference to FIG. 7. Note that the description of the same configuration as that of Embodiment 1 is omitted.

[0078] As shown in FIG. 7, a plurality of external dynamic pressure generating grooves 180 are provided in the circumferential direction on the sliding surface 108a of the thrust plate 108. The external dynamic pressure generating grooves 180 communicate with the external space on the outer diameter side (that is, the low-pressure chamber 20 (see FIG. 1)). That is, the sliding surface 108a is not provided with the internal dynamic pressure generating grooves 81 as in Embodiment 1, and the inner diameter side of the sliding surface 108a is formed into a flat surface by the surface 182a of the land 182.

[0079] FIG. 7 shows a state in which the side seal 7 is arranged closer to 12 o'clock from a position concentric with the thrust plate 108 (see FIG. 4(a)).

[0080] In this state, the sliding surface 7a overlaps a plurality of external dynamic pressure generating grooves 180 (that is, some of the dynamic pressure generating grooves) in the vicinity of 10 o'clock to 2 o'clock on the sliding surface 108a, and does not overlap a plurality of external dynamic pressure generating grooves 180 (that is, other dynamic pressure generating grooves) in the vicinity of 3 o'clock to 9 o'clock on the sliding surface 108a.

[0081] According to this, when the side seal 7 moves in the white arrow direction, a large dynamic pressure is generated at the acute corner portions 180e of each of the external dynamic pressure generating grooves 180 in the vicinity of 10 o'clock to 2 o'clock on the sliding surface 108a, and no dynamic pressure is generated at the portion in the vicinity of 3 o'clock to 9 o'clock on the sliding surface 108a.

[0082] In this way, since the dynamic pressure can be generated only by the external dynamic pressure generating groove 180 where the sliding surface 7a of the side seal 7 overlaps, it is possible to prevent the generation of an unintended negative pressure in other external dynamic pressure generating grooves 180 where the sliding surface 7a does not overlap.

[0083] In addition, in the second embodiment, a form in which a plurality of external dynamic pressure generating grooves 180 are provided in the circumferential direction and no internal dynamic pressure generating groove is provided is illustrated. However, a form in which a plurality of internal dynamic pressure generating grooves are provided in the circumferential direction and no external dynamic pressure generating groove is provided may also be used.

Embodiment

[0084] Next, the sliding surface 208a of the thrust plate 208 according to the third embodiment will be described with reference to FIG. 8. In addition, the description of the same configuration as that of the first embodiment is omitted.

[0085] As shown in FIG. 8, a plurality (three in the third embodiment) of non-communication grooves surrounded by lands 282 in the radial direction are arranged between each external dynamic pressure generating groove 280 and each internal dynamic pressure generating groove 281 on the sliding surface 208a of the thrust plate 208.

[0086] Specifically, the sliding surface 208a of the thrust plate 208 has a first non-communication groove 283 adjacent to the inner diameter side of the external dynamic pressure generating groove 280, a second non-communication groove 284 adjacent to the outer diameter side of the internal dynamic pressure generating groove 281, and a third non-communication groove 285 disposed between the first non-communication groove 283 and the second non-communication groove 284. The external dynamic pressure generating groove 280, the internal dynamic pressure generating groove 281, the first non-communication groove 283, the second non-communication groove 284, and the third non-communication groove 285 of the third embodiment have a circumferential width larger than the radial width.

[0087] The first non-communication groove 283 forms a substantially parallelogram when viewed axially, and acute-angled corners 283a and 283b are formed on the inner diameter side in the counterclockwise direction and the outer diameter side in the clockwise direction. The second non-communication groove 284 forms a substantially parallelogram when viewed axially, and acute-angled corners 284a and 284b are formed on the inner diameter side in the counterclockwise direction and the outer diameter side in the clockwise direction. The third non-communication groove 285 forms a substantially rectangular shape having a long side in the circumferential direction when viewed axially.

[0088] These outer dynamic pressure generating grooves 280, inner dynamic pressure generating grooves 281, first non-communication grooves 283, and second non-communication grooves 284 are arranged on an imaginary line (not shown) extending radially from the center point of the thrust plate 208. Further, the third non-communication groove 285 is arranged slightly shifted in the circumferential direction from the outer dynamic pressure generating grooves 280, inner dynamic pressure generating grooves 281, first non-communication grooves 283, and second non-communication grooves 284 arranged in the radial direction.

[0089] FIG. 8 shows a state in which the side seal 7 is arranged closer to 12 o'clock from a position concentric with the thrust plate 208 (see FIG. 4(a)).

[0090] In this state, in the region around 11 o'clock to 1 o'clock on the sliding surface 208a, the sliding surface 7a overlaps a plurality of outer dynamic pressure generating grooves 280. In the region around 2 o'clock to 4 o'clock on the sliding surface 208a, the sliding surface 7a overlaps a plurality of first non-communication grooves 283, second non-communication grooves 284, and third non-communication grooves 285. In the region around 5 o'clock to 7 o'clock on the sliding surface 208a, the sliding surface 7a overlaps a plurality of inner dynamic pressure generating grooves 281. In the region around 8 o'clock to 10 o'clock on the sliding surface 208a, the sliding surface 7a overlaps a plurality of first non-communication grooves 283, second non-communication grooves 284, and third non-communication grooves 285.

[0091] When the side seal 7 moves in the direction of the white arrow from the state of FIG. 8, hydrodynamic pressure is mainly generated at the portions near 11 o'clock to 1 o'clock and the portions near 5 o'clock to 7 o'clock on the sliding surface 208a by the plurality of outer hydrodynamic pressure generating grooves 280 and the plurality of inner hydrodynamic pressure generating grooves 281. In addition, hydrodynamic pressure can be generated at the portions near 2 o'clock to 4 o'clock and the portions near 8 o'clock to 10 o'clock on the sliding surface 208a by the plurality of first non-communication grooves 283, second non-communication grooves 284, and third non-communication grooves 285. Therefore, the inclination between the sliding surface 7a and the sliding surface 208a can be suppressed and separated.

[0092] Further, since the side seal 7 overlaps with any one of the outer hydrodynamic pressure generating groove 280, the inner hydrodynamic pressure generating groove 281, the first non-communication groove 283, the second non-communication groove 284, and the third non-communication groove 285 over the circumferential direction of the sliding surface 208a, hydrodynamic pressure can be generated over the circumferential direction regardless of the relative position between the side seal 7 and the sliding surface 208a.

[0093] Further, since the first non-communication groove 283, the second non-communication groove 284, and the third non-communication groove 285 are in a non-communication state with the external space, when the side seal 7 slides, fluid does not flow out from each non-communication groove to the external space, and hydrodynamic pressure can be surely generated. Furthermore, large hydrodynamic pressure can be generated by the corner portions 283a, 283b and the corner portions 284a, 284b.

[0094] In addition, since the first non-communication groove 283, the second non-communication groove 284, and the third non-communication groove 285 have different shapes respectively, the hydrodynamic pressure can be changed according to the relative position between the side seal 7 and the sliding surface 208a. That is, it is easy to design so as to appropriately separate the sliding surface 7a and the sliding surface 208a with respect to the eccentric rotational movement of the side seal 7.

Example

[0095] Next, the sliding surface 308a of the thrust plate 308 according to the fourth embodiment will be described with reference to FIG. 9. In addition, the description of the configuration that is the same as that of the first embodiment will be omitted.

[0096] As shown in FIG. 9, a plurality (three in the second embodiment) of non-communication grooves 383 are provided side by side in the radial direction between each outer hydrodynamic groove 380 and each inner hydrodynamic groove 381 on the sliding surface 308a of the thrust plate 308.

[0097] These non-communication grooves 383 form a substantially parallelogram of the same shape when viewed from the axial direction, and the outer hydrodynamic grooves 380, the inner hydrodynamic grooves 381, and each non-communication groove 383 are arranged side by side in the radial direction.

[0098] The side seal 7 overlaps with either the outer hydrodynamic groove 380, the inner hydrodynamic groove 381, or the non-communication groove 383 over the circumferential direction of the sliding surface 308a. Therefore, hydrodynamic pressure can be generated over the circumferential direction regardless of the relative position between the side seal 7 and the sliding surface 308a.

Embodiment

[0099] Next, the sliding surface 408a of the thrust plate 408 according to the fifth embodiment will be described with reference to FIG. 10. In addition, the description of the same configuration as that of the first embodiment will be omitted.

[0100] As shown in FIG. 10, a plurality (three in the fifth embodiment) of non-communication grooves 483 are provided side by side between each outer hydrodynamic groove 480 and each inner hydrodynamic groove 481 on the sliding surface 408a of the thrust plate 408. These outer hydrodynamic grooves 480, inner hydrodynamic grooves 481, and each non-communication groove 483 have a shape that is inverted from the various grooves of the second and third embodiments.

[0101] These rows of outer hydrodynamic grooves 480, inner hydrodynamic grooves 481, and each non-communication groove 483 arranged in the radial direction are arranged along the eccentric rotation direction of the side seal 7 from the outer hydrodynamic groove 480 toward the inner hydrodynamic groove 481. In other words, the outer hydrodynamic grooves 480, inner hydrodynamic grooves 481, and each non-communication groove 483 arranged in the radial direction are arranged obliquely in the circumferential direction. That is, they are arranged such that the dimensions between the circumferential directions of each groove are constant and they are continuous while being inclined in the circumferential direction. Note that the dimensions between the circumferential directions are not limited to being constant, and may increase or decrease at a predetermined ratio toward the outer diameter.

[0102] In this way, by forming the outer dynamic pressure generating groove 480, the inner dynamic pressure generating groove 481, and each non-communication groove 483 by reversing those in the second and third embodiments, dynamic pressure can be generated corresponding to the eccentric rotation direction of the side seal 7 in the direction opposite to that in the second and third embodiments.

Embodiment

[0103] Next, with reference to FIG. 11, the sliding surface 508a of the thrust plate 508 according to the sixth embodiment will be described. The description of the same configurations as those in the first embodiment will be omitted.

[0104] As shown in FIG. 11, a plurality of outer dynamic pressure generating grooves 580 and inner dynamic pressure generating grooves 581 are formed in the circumferential direction on the sliding surface 508a of the thrust plate 508. The outer dynamic pressure generating groove 580 has an acute-angled corner 580e formed at the inner diameter end in the counterclockwise direction. The inner dynamic pressure generating groove 581 has an acute-angled corner 581e formed at the outer diameter end in the counterclockwise direction. The outer dynamic pressure generating groove 580 communicates with the external space on the outer diameter side (that is, the low-pressure chamber 20 (see FIG. 1)), and the inner dynamic pressure generating groove 581 communicates with the external space on the inner diameter side (that is, the back pressure chamber 50 (see FIG. 1)).

[0105] In addition, between the outer dynamic pressure generating groove 580 and the inner dynamic pressure generating groove 581 adjacent to each other in the radial direction on the sliding surface 508a, a first non-communication groove 583, a second non-communication groove 584, and a third non-communication groove 585 are formed.

[0106] The first non-communication groove 583 adjacent to the inner diameter side of the outer dynamic pressure generating groove 580 forms a substantially parallelogram having acute-angled corners 583a and 583b on the inner diameter side in the counterclockwise direction and the outer diameter side in the clockwise direction.

[0107] In addition, the second non-communication groove 584 adjacent to the outer diameter side of the inner dynamic pressure generating groove 581 forms a substantially parallelogram having acute-angled corners 584a and 584b on the outer diameter side in the counterclockwise direction and the inner diameter side in the clockwise direction. The third non-communication groove 585 forms a substantially rectangle having a long side in the circumferential direction when viewed from the axial direction.

[0108] Further, the first non-communication groove 583 is displaced clockwise from the third non-communication groove 585 and is disposed on the outer diameter side thereof, and the external dynamic pressure generating groove 580 is displaced clockwise from the first non-communication groove 583 and is disposed on the outer diameter side thereof. That is, the center lines between the circumferential directions of the respective grooves are displaced in the circumferential direction, that is, they are arranged so that the center lines between the grooves adjacent in the radial direction are not continuous.

[0109] Also, the second non-communication groove 584 is displaced clockwise from the third non-communication groove 585 and is disposed on the inner diameter side thereof, and the external dynamic pressure generating groove 580 is displaced clockwise from the first non-communication groove 583 and is disposed on the inner diameter side thereof. That is, the center lines between the circumferential directions of the respective grooves are displaced in the circumferential direction, that is, they are arranged so that the center lines between the grooves adjacent in the radial direction are not continuous.

[0110] In the state of FIG. 11, in the portion around 11 o'clock to 1 o'clock on the sliding surface 508a, the sliding surface 7a overlaps a plurality of external dynamic pressure generating grooves 580. In the portion around 2 o'clock to 4 o'clock on the sliding surface 508a, the sliding surface 7a overlaps a plurality of first non-communication grooves 583, second non-communication grooves 584, and third non-communication grooves 585. In the portion around 5 o'clock to 7 o'clock on the sliding surface 508a, the sliding surface 7a overlaps a plurality of internal dynamic pressure generating grooves 581. In the portion around 8 o'clock to 10 o'clock on the sliding surface 508a, the sliding surface 7a overlaps a plurality of first non-communication grooves 583, second non-communication grooves 584, and third non-communication grooves 585.

[0111] When the side seal 7 moves in the direction of the white arrow from the state of FIG. 11, dynamic pressure is generated in the portion around 8 o'clock to 4 o'clock on the sliding surface 508a by the plurality of external dynamic pressure generating grooves 580 and the plurality of first non-communication grooves 583, second non-communication grooves 584, and third non-communication grooves 585.

[0112] On the other hand, in the portion around 7 o'clock on the sliding surface 508a, almost no dynamic pressure is generated by the plurality of internal dynamic pressure generating grooves 581, and negative pressure is generated in the portion around 5 o'clock to 6 o'clock on the sliding surface 508a.

[0113] In this way, hydrodynamic pressure can be generated in most of the circumferential direction of the sliding surface 508a, improving the lubricity between the sliding surfaces 7a and 508a. At the same time, negative pressure is generated in a part of the circumferential direction of the sliding surface 508a, and the sliding surfaces 7a and 508a are brought closer to each other, so that the state where the sliding surfaces 7a and 508a slide relative to each other can be maintained.

Embodiment

[0114] Next, the sliding surface 608a of the thrust plate 608 according to Embodiment 7 will be described with reference to FIG. 12. Note that the description of the same configuration as that in Embodiment 1 will be omitted.

[0115] As shown in FIG. 12, the inner hydrodynamic pressure generating groove 681 of the sliding surface 608a of the thrust plate 608 is partitioned by the land 682 so as to be non-communicating with the external space on the inner diameter side (that is, the back pressure chamber 50 (see FIG. 1)). Note that other shapes are the same as those in Embodiment 6.

[0116] According to this, since hydrodynamic pressure can be generated over the circumferential direction of the sliding surface 608a, the sliding surfaces 7a and 608a can be separated in a state where the relative inclination thereof is small.

Embodiment

[0117] Next, the sliding surface 708a of the thrust plate 708 according to Embodiment 8 will be described with reference to FIG. 13. Note that the description of the same configuration as that in Embodiment 1 will be omitted.

[0118] As shown in FIG. 13, each outer hydrodynamic pressure generating groove 780 in the sliding surface 708a of the thrust plate 708 is partitioned by the land 782 so as to be non-communicating with the external space on the outer diameter side (that is, the low pressure chamber 20 (see FIG. 1)). Also, each inner hydrodynamic pressure generating groove 781 communicates with the external space on the inner diameter side (that is, the back pressure chamber 50 (see FIG. 1)).

[0119] Further, between each external dynamic pressure generating groove 780 and each internal dynamic pressure generating groove 781, a first non-communication groove 783, a second non-communication groove 784, and a third non-communication groove 785 are arranged. These external dynamic pressure generating grooves 780, internal dynamic pressure generating grooves 781, first non-communication groove 783, second non-communication groove 784, and third non-communication groove 785 have shapes that are reversed from the various grooves of Examples 6 and 7.

[0120] Thus, by forming the external dynamic pressure generating groove 780, internal dynamic pressure generating groove 781, first non-communication groove 783, second non-communication groove 784, and third non-communication groove 785 in a shape reversed from that of Examples 6 and 7, dynamic pressure can be generated corresponding to the eccentric rotation direction of the side seal 7 in the opposite direction to that of Examples 6 and 7.

[0121] Further, since the external dynamic pressure generating groove 780 is partitioned in a non-communication state from the external space on the outer diameter side by the land 782, dynamic pressure can be surely generated when sliding relative to the side seal 7.

[0122] Also, when the side seal 7 is eccentrically rotated in the direction opposite to that in FIG. 13, i.e., counterclockwise, dynamic pressure can be generated over the circumferential direction of the sliding surface 708a, so that the sliding surfaces 7a and 708a can be separated in a state where the relative inclination is small.

[0123] As described above, the embodiments of the present invention have been described with reference to the drawings. However, the specific configuration is not limited to these embodiments, and modifications and additions within the scope not departing from the gist of the present invention are also included in the present invention.

[0124] In the above-described Examples 1 to 8, the aspect in which the side seal 7 as a sliding part is applied to the scroll compressor C used in an air conditioning system of an automobile or the like has been described. However, the present invention is not limited to this, and any rotary machine including an eccentric mechanism, for example, a scroll expander-compressor having an expander and a compressor integrated, may be applicable.

[0125] Further, the fluid existing in the spaces inside and outside the sliding surface of the sliding part may be any of gas, liquid, or a mixed state of gas and liquid.

[0126] Further, the sliding component of the present invention may be used in an environment where there is no pressure difference between the inside and outside of the sliding surface, as long as it has a sliding surface that relatively slides with eccentric rotation, not limited to an environment where there is a pressure difference between the inside and outside of the sliding surface. Further, the sliding component of the present invention does not need to have a function as a seal, as long as it can stably reduce the frictional resistance of the sliding surface.

[0127] In the above Examples 1 to 8, the side seal having a sliding surface that relatively slides was described as being made of resin and the thrust plate as being made of metal, but the material of the sliding component may be freely selected according to the use environment and the like.

[0128] In the above Examples 1 to 8, the mode in which a dynamic pressure generating groove is formed in the sliding region of the sliding surface of the thrust plate (see FIG. 4) was described, but not limited thereto, a dynamic pressure generating groove may be formed in the sliding surface of the side seal which is a sliding component having a sliding surface that relatively slides with eccentric rotation. Further, dynamic pressure generating grooves may be formed in both the sliding surface of the side seal and the sliding surface of the thrust plate.

[0129] In the above Examples 1 to 8, the configuration in which the sliding surface of the side seal and the sliding surface of the thrust plate as the sliding component relatively slide with eccentric rotation was described, but not limited thereto, only one of the side seal and the thrust plate may be provided, and a dynamic pressure generating groove may be formed in the sliding surface that relatively slides with eccentric rotation. For example, when only the thrust plate is provided, a dynamic pressure generating groove may be formed in one or both of the sliding surface of the thrust plate as the sliding component and the back surface of the end plate of the movable scroll. Further, when only the side seal is provided, a dynamic pressure generating groove may be formed in the sliding surface of the side seal as the sliding component. In this case, the side seal also functions as a thrust bearing that abuts against the inner peripheral surface of the inner casing and receives the axial load of the movable scroll.

[0130] Further, when there is no side seal and thrust plate, and the back surface of the end plate of the movable scroll contacts the inner peripheral surface of the inner casing to function as a thrust bearing that receives the axial load of the movable scroll, a sliding surface may be formed on the back surface of the end plate of the movable scroll or a dynamic pressure generating groove may be formed on the inner casing.

[0131] In addition, although a form has been exemplified in which there is an external space on the low-pressure side on the outer diameter side of the side seal and an external space on the high-pressure side on the inner diameter side of the side seal, there may be an external space on the low-pressure side on the inner diameter side of the side seal and an external space on the high-pressure side on the outer diameter side of the side seal.

[0132] In addition, in the above Examples 1 to 8, a corner portion forming an acute angle has been exemplified as the tapered portion of the outer dynamic pressure generating groove and the inner dynamic pressure generating groove. However, the present invention is not limited to this, and the dynamic pressure generating groove may be tapered toward the eccentric rotation direction, and the tip thereof may form a plane or a curved surface orthogonal to the eccentric rotation direction.

[0133] In addition, in the above Examples 1 to 8, the opposed sliding surfaces have been exemplified in a form in which when they overlap with one outer dynamic pressure generating groove and one inner dynamic pressure generating groove, they relatively slide with respect to the sliding surface so as not to overlap with the other outer dynamic pressure generating groove and inner dynamic pressure generating groove. However, the opposed sliding surfaces may be configured to relatively slide so as to always overlap with each outer dynamic pressure generating groove and each inner dynamic pressure generating groove.

[0134] In addition, in the above Examples 1 to 8, a form in which the side walls of the outer dynamic pressure generating groove and the side walls of the inner dynamic pressure generating groove are curved has been exemplified. However, they may be formed in a straight line.

[0135] In addition, the number of the outer dynamic pressure generating grooves and the inner dynamic pressure generating grooves is not limited to the forms of the above Examples 1 to 8 and can be freely changed. In Example 1 and the above Examples 3 to 8, a form in which the outer dynamic pressure generating grooves and the inner dynamic pressure generating grooves are provided in the same number has been exemplified. However, the present invention is not limited to this, and they may be provided in different numbers.

[0136] In addition, in the above-described First Embodiment and Third to Eighth Embodiments, the outer hydrodynamic groove has been described as a hydrodynamic groove and the inner hydrodynamic groove as another hydrodynamic groove. However, the outer hydrodynamic groove may be another hydrodynamic groove and the inner hydrodynamic groove may be a hydrodynamic groove.

Explanation of Signs

[0137] 4 Scroll Compression Mechanism 7 Side Seal 7a Sliding Surface (Opposing Sliding Surface) 8 Thrust Plate (Sliding Part) 8a Sliding Surface 20 Low-Pressure Chamber (External Space on the Outer Diameter Side) 41 Fixed Scroll 42 Movable Scroll 50 Back-Pressure Chamber (External Space on the Inner Diameter Side) 80, 80A to 80B Outer Hydrodynamic Groove (Hydrodynamic Groove) 80e Corner 81, 81A to 81B Inner Hydrodynamic Groove (Another Hydrodynamic Groove) 81e Corner 82 Land 108 Thrust Plate (Sliding Part) 108a Sliding Surface 180 Outer Hydrodynamic Groove (Hydrodynamic Groove) 180e Corner 208 Thrust Plate (Sliding Part) 208a Sliding Surface 280 Outer Hydrodynamic Groove (Hydrodynamic Groove) 281 Inner Hydrodynamic Groove (Another Hydrodynamic Groove) 283 First Non-Communication Groove 284 Second Non-Communication Groove 285 Third Non-Communication Groove 308 Thrust Plate (Sliding Part) 308a Sliding Surface 380 Outer Hydrodynamic Groove (Hydrodynamic Groove) 381 Inner Hydrodynamic Groove (Another Hydrodynamic Groove) 383 Non-Communication Groove 408 Thrust Plate (Sliding Part) 408a Sliding Surface 480 External dynamic pressure generating groove (dynamic pressure generating groove) 481 Internal dynamic pressure generating groove (another dynamic pressure generating groove) 483 Non - communicating groove 508 Thrust plate (sliding part) 508a Sliding surface 580 External dynamic pressure generating groove (dynamic pressure generating groove) 580e Corner 581 Internal dynamic pressure generating groove (another dynamic pressure generating groove) 581e Corner 583 First non - communicating groove 584 Second non - communicating groove 585 Third non - communicating groove 608 Thrust plate (sliding part) 608a Sliding surface 681 Internal dynamic pressure generating groove (another dynamic pressure generating groove) 682 Land 708 Thrust plate (sliding part) 708a Sliding surface 780 External dynamic pressure generating groove (dynamic pressure generating groove) 781 Internal dynamic pressure generating groove (another dynamic pressure generating groove) 783 First non - communicating groove 784 Second non - communicating groove 785 Third non - communicating groove C Scroll compressor M Driving motor

Claims

1. A sliding component having a sliding surface that relatively slides with eccentric rotation, wherein on at least one of the inner diameter side and the outer diameter side of the sliding surface, a plurality of dynamic pressure generating grooves that taper and extend toward the downstream side in the relative eccentric rotation direction with respect to the opposing sliding surface are provided in the circumferential direction, wherein on at least the other of the inner diameter side and the outer diameter side of the sliding surface, a plurality of other dynamic pressure generating grooves that taper and extend toward the downstream side in the relative eccentric rotation direction with respect to the opposing sliding surface are provided in the circumferential direction, wherein the sliding surface and the opposing sliding surface relatively slide with eccentric rotation such that, among the plurality of dynamic pressure generating grooves, the opposing sliding surface overlaps with some of the dynamic pressure generating grooves and does not overlap with the other dynamic pressure generating grooves, and among the plurality of the other dynamic pressure generating grooves, the opposing sliding surface overlaps with some of the other dynamic pressure generating grooves and does not overlap with the other of the other dynamic pressure generating grooves.

2. The sliding component according to claim 1, wherein an end portion on the downstream side in the eccentric rotation direction of the dynamic pressure generating groove is an angular portion having an acute angle.

3. The sliding component according to claim 1 or 2, wherein the dynamic pressure generating groove communicates with the external space of the sliding surface.

4. The sliding component according to any one of claims 1 to 3, wherein the tapered portions of the dynamic pressure generating grooves adjacent to each other in the radial direction and the tapered portions of the other dynamic pressure generating grooves are formed to face in opposite directions in the eccentric rotation direction.

5. The sliding component according to any one of claims 1 to 4, wherein the dynamic pressure generating groove and the other dynamic pressure generating groove are separated from each other in the radial direction, and this separation width is larger than the radial width of the annular opposing sliding surface that relatively slides with the sliding surface.

6. The sliding component according to any one of claims 1 to 5, wherein a plurality of non - communicating grooves surrounded by a land that partitions the dynamic pressure generating groove and the other dynamic pressure generating groove are provided in the circumferential direction between the dynamic pressure generating groove and the other dynamic pressure generating groove.

7. The sliding component according to claim 6, wherein a plurality of the non - communicating grooves are arranged in the radial direction between the dynamic pressure generating groove and the other dynamic pressure generating groove adjacent to each other in the radial direction, and each non - communicating groove has a different shape.

8. A sliding component having a sliding surface that relatively slides with eccentric rotation, wherein on at least one of the inner diameter side and the outer diameter side of the sliding surface, a plurality of dynamic pressure generating grooves that taper and extend toward the downstream side in the relative eccentric rotation direction with respect to the opposing sliding surface are provided in the circumferential direction, On at least the other one of the inner diameter side and the outer diameter side of the sliding surface, a plurality of other dynamic pressure generating grooves that taper and extend toward the downstream side in the relative eccentric rotation direction with respect to the opposing sliding surface are provided in the circumferential direction. The dynamic pressure generating groove and the other dynamic pressure generating groove are separated in the radial direction, and the separation width is larger than the radial width of the annular opposing sliding surface that slides relative to the sliding surface. A sliding component. **Claim 9**: The sliding component according to claim 8, wherein the end portion on the downstream side in the eccentric rotation direction of the dynamic pressure generating groove is an angular portion having an acute angle. **Claim 10**: The sliding component according to claim 8 or 9, wherein the dynamic pressure generating groove communicates with the external space of the sliding surface. **Claim 11**: The sliding surface and the opposing sliding surface relatively slide with eccentric rotation such that the opposing sliding surface overlaps some of the plurality of dynamic pressure generating grooves and does not overlap the other dynamic pressure generating grooves. The sliding component according to any one of claims 8 to 10. **Claim 12**: The sliding component according to any one of claims 8 to 11, wherein the tapered portions of the dynamic pressure generating grooves adjacent in the radial direction and the tapered portions of the other dynamic pressure generating grooves are formed to face in opposite directions in the eccentric rotation direction. **Claim 13**: The sliding component according to any one of claims 8 to 12, wherein a plurality of non-communication grooves surrounded by a land that partitions the dynamic pressure generating groove and the other dynamic pressure generating groove are provided in the circumferential direction between the dynamic pressure generating groove and the other dynamic pressure generating groove. **Claim 14**: The sliding component according to claim 13, wherein a plurality of the non-communication grooves are arranged in the radial direction between the dynamic pressure generating groove and the other dynamic pressure generating groove adjacent in the radial direction, and each non-communication groove has a different shape. **Claim 15**: A sliding component having a sliding surface that relatively slides with eccentric rotation, On at least one of the inner diameter side and the outer diameter side of the sliding surface, a plurality of dynamic pressure generating grooves that taper and extend toward the downstream side in the relative eccentric rotation direction with respect to the opposing sliding surface are provided in the circumferential direction. On at least the other one of the inner diameter side and the outer diameter side of the sliding surface, a plurality of other dynamic pressure generating grooves that taper and extend toward the downstream side in the relative eccentric rotation direction with respect to the opposing sliding surface are provided in the circumferential direction. A sliding component in which a plurality of non-communication grooves surrounded by a land that partitions the dynamic pressure generating groove and the other dynamic pressure generating groove are provided in the circumferential direction between the dynamic pressure generating groove and the other dynamic pressure generating groove.

16. The sliding component according to claim 15, wherein the end portion on the downstream side in the eccentric rotation direction of the hydrodynamic groove forms an acute-angled corner.

17. The sliding component according to claim 15 or 16, wherein the hydrodynamic groove communicates with the external space of the sliding surface.

18. The sliding component according to any one of claims 15 to 17, wherein the sliding surface and the opposing sliding surface relatively slide with eccentric rotation such that the opposing sliding surface overlaps a part of the plurality of hydrodynamic grooves and does not overlap the other hydrodynamic grooves.

19. The sliding component according to any one of claims 15 to 18, wherein the tapered portions of the hydrodynamic grooves adjacent to each other in the radial direction and the tapered portions of the other hydrodynamic grooves are formed to face opposite directions in the eccentric rotation direction.

20. The sliding component according to any one of claims 15 to 19, wherein the hydrodynamic groove and the other hydrodynamic groove are separated from each other in the radial direction, and the separation width is larger than the radial width of the annular opposing sliding surface that relatively slides with the sliding surface.

21. The sliding component according to any one of claims 15 to 20, wherein a plurality of non-communication grooves are arranged in the radial direction between the hydrodynamic groove adjacent to each other in the radial direction and the other hydrodynamic groove, and each non-communication groove has a different shape.

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