JP2014092238A - Thrust ball bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thrust ball bearing which sufficiently supplies a lubricant to each contact part of the through ball bearing and prevents abrasion and seizure of races and a holder.SOLUTION: A thrust ball bearing includes: upper and lower races 31, 32 which are arranged in parallel with each other so as to be spaced away from each other in an axial direction; multiple balls 33 which are disposed between the upper and lower races 31, 32 so as to roll; and a holder 34 which holds the multiple balls 33 at a substantially equal interval in a circumferential direction. The holder 34 includes lubrication passages 36, 37 which penetrate through the holder 34 in a plate thickness direction and allow upper and lower surfaces of the holder 34 to communicate with each other.

Description

  The present invention relates to a thrust ball bearing, and more particularly to a thrust ball bearing used in a hermetic compressor such as a refrigerator-freezer or an air conditioner.

  Sealed compressors such as refrigerators and air conditioners are required to be highly efficient, such as reducing power consumption and preventing noise, in order to respond to recent environmental concerns. As part of the countermeasure, a thrust ball bearing is used in a portion that rotatably supports the compressor shaft. By using a thrust ball bearing in this portion, the rotational characteristics are improved and the efficiency of the compressor is improved.

  And as a conventional thrust ball bearing used for a hermetic compressor such as a refrigerator and a refrigerator, a pair of races that are formed in an annular shape and spaced apart in parallel in the axial direction are arranged between the pair of races. A plurality of balls arranged in a freely rolling manner and a cage that is arranged between a pair of races and holds the plurality of balls at substantially equal intervals, and the plurality of balls are staggered in a double row in the circumferential direction of the race There are known ones that are arranged and have high rigidity to extend the life of the bearing (for example, see Patent Document 1) and those in which the inner diameter surface of the cage is formed in a flat shape (for example, see Patent Document 2). .

Japanese Patent Laid-Open No. 08-320018 Japanese Patent No. 4268519

  However, in the thrust ball bearing described in Patent Document 1, since the rolling surfaces of the upper and lower races are flat, the contact area with the balls is small, the surface pressure environment is high, and the upper and lower races are easily worn. In addition, when a thrust ball bearing is used in a compressor built in a refrigerator-freezer, the coolant is mixed into the lubricating oil inside the bearing and operation is performed in a low-viscosity environment. This could cause wear.

  Further, in the thrust ball bearing described in Patent Document 2, since the inner diameter surface of the cage is a flat shape, when the inner diameter surface of the cage contacts the shaft, the cage may be rotated around the shaft. For this reason, the normal rotation and revolution of the plurality of balls are hindered by the interaction between the cage and the plurality of balls, and slippage occurs between the plurality of balls and the rolling surface, resulting in early wear of the race. There was a possibility of wear of the cage.

  The present invention has been made in view of the above-described problems, and its object is to sufficiently supply a lubricant to each contact portion of a thrust ball bearing to prevent wear and seizure of the race and the cage. It is an object of the present invention to provide a thrust ball bearing that can be used.

The above object of the present invention can be achieved by the following constitution.
(1) A pair of races that are formed in an annular shape and are arranged in parallel apart from each other in the axial direction, a plurality of balls that are arranged to freely roll between the pair of races, and a pair of races, A thrust ball bearing comprising: a retainer that retains a plurality of balls in the circumferential direction at substantially equal intervals; and the retainer penetrates in the plate thickness direction and communicates with the upper and lower surfaces of the retainer. A thrust ball bearing comprising:
(2) The thrust ball bearing according to (1), wherein the lubrication passage is a groove extending in a plate thickness direction of the cage, and is formed on at least one of an inner diameter surface and an outer diameter surface of the cage.
(3) The thrust ball bearing according to (1), wherein the lubrication passage is a groove extending in a plate thickness direction of the cage, and is formed on an inner surface of a pocket that holds the ball of the cage.
(4) The thrust ball bearing according to (1), wherein the lubrication passage is a through-hole penetrating the cage in the plate thickness direction.
(5) The cage has an inner diameter surface that is chamfered at both ends in the axial direction, or an inner diameter surface that has a circular arc shape that bulges inward in the radial direction. The thrust ball bearing as described in any one.
(6) At least one rolling groove in contact with the ball is provided in at least one of the pair of races, the radius of the rolling groove is set to 60% or more of the diameter of the ball, and the depth of the rolling groove is The thrust ball bearing according to any one of (1) to (4), wherein the thrust ball bearing is set to 60 μm or less.
(7) The lubricant that lubricates each contact portion of the thrust ball bearing is supplied between the upper race disposed above the ball of the pair of races and the cage (1). Thrust ball bearing as described in any one of-(6).
(8) The thrust ball bearing according to any one of (1) to (7), wherein the thrust ball bearing is used for a compressor incorporated in a refrigerator-freezer or an air conditioner.

  According to the thrust ball bearing of the present invention, since the cage includes at least one lubrication passage that penetrates in the plate thickness direction and communicates the upper and lower surfaces of the cage, lubrication supplied between the upper race and the cage is provided. The agent can be sufficiently supplied to each contact portion of the thrust ball bearing. As a result, wear and seizure of the race and the cage can be prevented, so that the life of the thrust ball bearing can be extended.

It is sectional drawing of the compressor in which 1st Embodiment of the thrust ball bearing which concerns on this invention was used. It is an expanded sectional view explaining the thrust ball bearing shown in FIG. (A) is a top view of the holder | retainer shown in FIG. 2, (b) is the sectional view on the AA line of Fig.3 (a). It is a figure explaining 2nd Embodiment of the thrust ball bearing which concerns on this invention, (a) is a top view of a holder | retainer, (b) is the BB sectional drawing of Fig.4 (a). It is a top view of the holder | retainer for demonstrating 3rd Embodiment of the thrust ball bearing which concerns on this invention. It is a top view of a cage for explaining a 4th embodiment of a thrust ball bearing concerning the present invention. It is an expanded sectional view explaining 5th Embodiment of the thrust ball bearing which concerns on this invention. It is an expanded sectional view explaining 6th Embodiment of the thrust ball bearing which concerns on this invention. It is an expanded sectional view explaining a 7th embodiment of a thrust ball bearing concerning the present invention.

  Hereinafter, a compressor in which each embodiment of a thrust ball bearing according to the present invention is used will be described in detail based on the drawings.

(First embodiment)
First, with reference to FIGS. 1-3, the compressor in which 1st Embodiment of the thrust ball bearing which concerns on this invention was used is demonstrated.

  As shown in FIG. 1, the compressor 10 of the present embodiment has a structure in which an airtight container 11 is provided and a drive system and the like are disposed therein. Inside the sealed container 11, there are provided a rotation drive unit 14 having a stator 12 and a rotor 13, a refrigerant (for example, refrigerant gas) that is compressed or expanded by the operation of the rotation drive unit 14, and the like. The compressor 10 is built in a refrigerator-freezer or an air conditioner.

  The rotor 13 is connected to the shaft 15 in an integrated state by press fitting. The shaft 15 is formed on the main shaft portion 16 to which the rotor 13 is fixed, the flange portion 17 formed on the upper end portion of the main shaft portion 16, and the upper surface of the flange portion 17, and is arranged eccentrically with respect to the main shaft portion 16. And an eccentric shaft portion 18.

  A cylinder block 20 is provided at an upper one side position of the shaft 15. The cylinder block 20 has a substantially cylindrical compression chamber 21. A piston 22 is removably inserted into the compression chamber 21. The piston 22 is connected to the eccentric shaft portion 18 by a connecting member 23.

  The main shaft portion 16 of the shaft 15 is inserted through the main bearing 19 along the vertical direction. A thrust ball bearing 30 is disposed between the lower surface of the flange portion 17 of the shaft 15 and the upper surface of the main bearing 19. As a result, the shaft 15 is rotatably supported, and the gravity direction load (self-weight) of the shaft 15 and the rotor 13 is supported.

  As shown in FIG. 2, the thrust ball bearing 30 is formed in an annular shape, and can freely roll between a pair of upper and lower upper and lower races 31 and 32 that are spaced apart from each other in the axial direction and arranged in parallel. A plurality of balls 33 disposed between the upper and lower races 31 and 32, and a retainer 34 that holds the plurality of balls 33 in the circumferential direction at substantially equal intervals, and is loosely fitted to the main shaft portion 16. Yes. In the present embodiment, the upper and lower races 31, 32 and the plurality of balls 33 are made of metal.

  The upper and lower races 31 and 32 are each formed of an annular flat plate, and the rolling surfaces 31 a and 32 a that are in contact with the plurality of balls 33 of the upper and lower races 31 and 32 are formed in a flat shape. A hardened surface layer by nitriding treatment may be formed on the upper and lower races 31 and 32 and the plurality of balls 33. In the nitriding treatment, the surfaces of the upper and lower races 31 and 32 and the plurality of balls 33 are washed with, for example, benzine, and then thermally reacted with a nitrogen compound to form a compound reaction film on the surface. Done.

  As shown in FIG. 3, the cage 34 is formed at substantially equal intervals in the circumferential direction, and is substantially equal in the circumferential direction to a plurality of pockets 35 that hold the balls 33 in a rollable manner and an inner diameter surface 41 of the cage 34. A plurality of inner circumferential grooves (lubricating passages) 36 formed at intervals and a plurality of outer circumferential grooves (lubricating passages) 37 formed at substantially equal intervals in the circumferential direction on the outer diameter surface 42 of the cage 34 are provided.

  The inner circumferential groove 36 and the outer circumferential groove 37 are grooves extending in the plate thickness direction of the cage 34, and constitute a lubricating passage that penetrates the cage 34 in the plate thickness direction and communicates the upper and lower surfaces of the cage 34. Further, the inner circumferential groove 36 and the outer circumferential groove 37 are respectively formed between the pockets 35 adjacent in the circumferential direction. In addition, the installation number, installation position, and shape of the inner peripheral groove 36 and the outer peripheral groove 37 are arbitrary. Moreover, the inner peripheral groove | channel 36 and the outer peripheral groove | channel 37 should just be provided in any one.

  As shown in FIG. 2, an oil passage 24 for sending lubricating oil (lubricant) is formed in the main shaft portion 16, and the oil passage 24 includes an upper race 31 and a cage 34 for the thrust ball bearing 30. And an opening 25 that opens toward each other. The lubricating oil discharged from the opening 25 of the oil passage 24 is supplied between the upper race 31 and the retainer 34 of the thrust ball bearing 30 to lubricate the contact portion between the upper race 31 and the plurality of balls 33. Then, while lubricating the contact portion between the pocket 35 and the ball 33, it flows downward through the pocket 35, the inner circumferential groove 36, and the outer circumferential groove 37, and lubricates the contact portion between the lower race 32 and the plurality of balls 33.

  In the case of a conventional thrust ball bearing that does not include the inner circumferential groove 36 and the outer circumferential groove 37, the clearance between the pocket 35 and the ball 33 and the clearance between the cage 34 and the main shaft portion 16 are small, and the flow resistance of the lubricating oil is large. There is a possibility that the lubrication of the contact portion between the lower race 32 and the plurality of balls 33 is insufficient. However, in the thrust ball bearing 30 of the present embodiment, the lubricating oil supplied between the upper race 31 and the cage 34 passes through the inner peripheral groove 36 and the outer peripheral groove 37 having a small flow resistance to the lower race 32 side. As a result, the contact portion between the lower race 32 and the plurality of balls 33 can be reliably lubricated. Thereby, wear and seizure of the upper and lower races 31 and 32 and the cage 34 are prevented.

  As described above, according to the thrust ball bearing 30 of the present embodiment, the upper and lower surfaces of the cage 34 are penetrated through the inner diameter surface 41 and the outer diameter surface 42 of the cage 34 in the thickness direction of the cage 34. Since the plurality of inner circumferential grooves 36 and the plurality of outer circumferential grooves 37 that are communicated are formed, the lubricant supplied between the upper race 31 and the cage 34 is sufficiently applied to each contact portion of the thrust ball bearing 30. Can be supplied. Thereby, since wear and seizure of the upper and lower races 31 and 32 and the cage 34 can be prevented, the life of the thrust ball bearing 30 can be extended.

(Second Embodiment)
Next, a second embodiment of the thrust ball bearing according to the present invention will be described with reference to FIG. Note that portions that are the same as or equivalent to those of the first embodiment are denoted by the same reference numerals in the drawings, and description thereof is omitted or simplified.

  In the cage 34 of the present embodiment, as shown in FIG. 4, the inner circumferential groove 36 and the outer circumferential groove 37 of the first embodiment are deleted, and the thickness direction of the cage 34 along the inner surface of the pocket 35 is removed. A lubricating groove 38 extending in the direction is formed. The lubrication groove 38 forms a lubrication passage that penetrates the retainer 34 in the thickness direction and communicates the upper and lower surfaces of the retainer 34. The lubrication groove 38 is provided along the radial direction of the cage 34 in order to avoid contact between the balls 33 and the lubrication groove 38. In addition, the installation number, installation position, and shape of the lubrication groove 38 are arbitrary.

  In the present embodiment, the lubricating oil supplied between the upper race 31 and the retainer 34 of the thrust ball bearing 30 lubricates the contact portion between the upper race 31 and the plurality of balls 33, and then the pocket 35 and the ball 35. While lubricating the contact part of 33, it flows below through the pocket 35 and the lubrication groove 38, and lubricates the contact part of the lower race 32 and the some ball | bowl 33. FIG.

As described above, according to the thrust ball bearing 30 of the present embodiment, lubrication that allows the upper and lower surfaces of the cage 34 to communicate with the inner side surface of the pocket 35 of the cage 34 in the plate thickness direction of the cage 34. Since the groove 38 is formed, the lubricant supplied between the upper race 31 and the cage 34 can be sufficiently supplied to each contact portion of the thrust ball bearing 30. Thereby, since wear and seizure of the upper and lower races 31 and 32 and the cage 34 can be prevented, the life of the thrust ball bearing 30 can be extended. Further, since the lubricating groove 38 is in the vicinity of the contact portion between the lower race 32 and the ball 33, the contact portion between the lower race 32 and the ball 33 can be efficiently lubricated. Further, since the lubrication groove 38 is formed on the inner surface of the pocket 35, the contact portion between the pocket 35 and the ball 33 can be efficiently lubricated.
About another structure and an effect, it is the same as that of the said 1st Embodiment.

(Third embodiment)
Next, a third embodiment of the thrust ball bearing according to the present invention will be described with reference to FIG. Note that portions that are the same as or equivalent to those of the first embodiment are denoted by the same reference numerals in the drawings, and description thereof is omitted or simplified.

  In the cage 34 of the present embodiment, as shown in FIG. 5, the inner circumferential groove 36 and the outer circumferential groove 37 of the first embodiment are deleted, and a pair of pockets 35 adjacent to each other in the circumferential direction of the cage 34 are paired. Each through hole 39 is formed. The through hole 39 constitutes a lubricating passage that penetrates the retainer 34 in the thickness direction and communicates the upper and lower surfaces of the retainer 34. In addition, the installation number, installation position, and shape of the through hole 39 are arbitrary.

  In the present embodiment, the lubricating oil supplied between the upper race 31 of the thrust ball bearing 30 and the cage 34 lubricates the contact portions of the upper race 31 and the plurality of balls 33, and then passes through the through holes 39. The lower race 32 and the plurality of balls 33 are lubricated at the contact portions.

As described above, according to the thrust ball bearing 30 of the present embodiment, since the through hole 39 penetrating in the plate thickness direction is formed in the retainer 34, it is supplied between the upper race 31 and the retainer 34. The lubricant can be sufficiently supplied to each contact portion of the thrust ball bearing 30. Thereby, since wear and seizure of the upper and lower races 31 and 32 and the cage 34 can be prevented, the life of the thrust ball bearing 30 can be extended.
About another structure and an effect, it is the same as that of the said 1st Embodiment.

(Fourth embodiment)
Next, with reference to FIG. 6, 4th Embodiment of the thrust ball bearing which concerns on this invention is described. Note that portions that are the same as or equivalent to those of the first embodiment are denoted by the same reference numerals in the drawings, and description thereof is omitted or simplified.

  In the cage 34 of the present embodiment, as shown in FIG. 6, the inner circumferential groove 36 and the outer circumferential groove 37 of the first embodiment are formed on the inner diameter surface 41 and the outer diameter surface 42 of the cage 34, respectively. Lubricating grooves 38 of the second embodiment are formed in each pocket 35 of the vessel 34.

  In the present embodiment, the lubricating oil supplied between the upper race 31 and the retainer 34 of the thrust ball bearing 30 lubricates the contact portion between the upper race 31 and the plurality of balls 33, and then the pocket 35 and the balls 33. While lubricating the contact portion, it flows downward through the pocket 35, the inner circumferential groove 36, the outer circumferential groove 37, and the lubricating groove 38, and lubricates the contact portion of the lower race 32 and the plurality of balls 33.

As described above, according to the thrust ball bearing 30 of the present embodiment, the upper and lower surfaces of the cage 34 are penetrated through the inner diameter surface 41 and the outer diameter surface 42 of the cage 34 in the thickness direction of the cage 34. A plurality of inner peripheral grooves 36 and a plurality of outer peripheral grooves 37 are formed to be communicated with each other, and the upper and lower surfaces of the retainer 34 penetrate through the inner surface of each pocket 35 of the retainer 34 in the thickness direction of the retainer 34. Therefore, the lubricant supplied between the upper race 31 and the cage 34 can be sufficiently supplied to each contact portion of the thrust ball bearing 30. Thereby, since wear and seizure of the upper and lower races 31 and 32 and the cage 34 can be prevented, the life of the thrust ball bearing 30 can be extended.
About another structure and an effect, it is the same as that of the said 1st Embodiment.

(Fifth embodiment)
Next, a fifth embodiment of the thrust ball bearing according to the present invention will be described with reference to FIG. Note that portions that are the same as or equivalent to those of the first embodiment are denoted by the same reference numerals in the drawings, and description thereof is omitted or simplified.

  In the present embodiment, as shown in FIG. 7, the inner circumferential groove 36 and the outer circumferential groove 37 of the first embodiment are respectively formed on the inner diameter surface 41 and the outer diameter surface 42 of the cage 34, and the inner diameter of the cage 34 is also formed. Arc-shaped chamfers 41 a are respectively provided at both axial ends of the surface 41.

  The axial width L1 of the chamfer 41a on one side is set to 30% to 45% with respect to the axial width L2 of the cage. Specifically, for example, L1 = 0.7 mm to 1.03 mm, L2 = 2.3 mm, and L1 / L2 × 100 = 30% to 45%. In the present embodiment, the chamfer 41a may be a straight chamfer instead of an arc chamfer.

As described above, according to the thrust ball bearing 30 of the present embodiment, since the retainer 34 has the inner diameter surface 41 with the chamfer 41a at both ends in the axial direction, the inner diameter of the retainer 34 that contacts the shaft 15 is obtained. The area of the surface 41 can be reduced. Thereby, in addition to the lubrication performance improvement effect by the inner peripheral groove 36 and the outer peripheral groove 37, even if the retainer 34 contacts the shaft 15, the accompanying rotation of the retainer 34 can be suppressed. Early wear of the upper and lower races 31 and 32 and wear of the cage 34 due to the accompanying rotation can be suppressed.
About another structure and an effect, it is the same as that of the said 1st Embodiment.

(Sixth embodiment)
Next, a sixth embodiment of the thrust ball bearing according to the present invention will be described with reference to FIG. Note that portions that are the same as or equivalent to those of the first embodiment are denoted by the same reference numerals in the drawings, and description thereof is omitted or simplified.

  In the present embodiment, as shown in FIG. 8, the inner circumferential groove 36 and the outer circumferential groove 37 of the first embodiment are formed on the inner diameter surface 41 and the outer diameter surface 42 of the cage 34, respectively. The surface 41 is formed in a circular arc shape that bulges radially inward.

  The radius of curvature R1 of the arc of the inner diameter surface 41 is set to 50% or more and less than 100% with respect to the axial width L2 of the cage 34. More preferably, the radius of curvature R1 of the arc of the inner diameter surface 41 is set to 50% to 76% with respect to the axial width L2 of the cage 34. Specifically, for example, R1 = 1.15 mm, 1.45 mm, 1.75 mm, L2 = 2.3 mm, and R1 / L2 × 100 = 50%, 63%, and 76% are set.

As described above, according to the thrust ball bearing 30 of the present embodiment, the retainer 34 has the inner diameter surface 41 having a circular arc shape that bulges inward in the radial direction, and therefore the inner diameter of the retainer 34 that contacts the shaft 15. The area of the surface 41 can be reduced. Thereby, in addition to the lubrication performance improvement effect by the inner peripheral groove 36 and the outer peripheral groove 37, even if the retainer 34 contacts the shaft 15, the accompanying rotation of the retainer 34 can be suppressed. Early wear of the upper and lower races 31 and 32 and wear of the cage 34 due to the accompanying rotation can be suppressed.
About another structure and an effect, it is the same as that of the said 1st Embodiment.

(Seventh embodiment)
Next, a seventh embodiment of the thrust ball bearing according to the present invention will be described with reference to FIG. Note that portions that are the same as or equivalent to those of the first embodiment are denoted by the same reference numerals in the drawings, and description thereof is omitted or simplified.

  In the present embodiment, as shown in FIG. 9, the inner circumferential groove 36 and the outer circumferential groove 37 of the first embodiment are respectively formed on the inner diameter surface 41 and the outer diameter surface 42 of the cage 34, and the upper and lower races 31, 32 are formed. The rolling grooves 31b and 32b are formed on the surface in contact with the ball 33, respectively.

  The radius (curvature) R2 of the rolling grooves 31b and 32b is set to 60% or more of the diameter D of the ball 33, and the depth H of the rolling grooves 31b and 32b is set to 60 μm or less. The rolling grooves 31b and 32b are formed simultaneously when the upper and lower races 31 and 32 are pressed.

As described above, according to the thrust ball bearing 30 of the present embodiment, the upper and lower races 31 and 32 are formed with the rolling grooves 31b and 32b in contact with the balls 33, respectively, and the radius R2 of the rolling grooves 31b and 32b is set. Since the diameter 33 of the ball 33 is set to 60% or more of the diameter D and the depth H of the rolling grooves 31b and 32b is set to 60 μm or less, the rolling position of the ball 33 is regulated by the rolling grooves 31b and 32b. It is possible to prevent the cage 34 guided by 33 from coming into contact with the shaft 15. Thereby, in addition to the lubricating performance improvement effect by the inner periphery groove | channel 36 and the outer periphery groove | channel 37, since the slip between the ball | bowl 33 and the races 31 and 32 can be prevented, the abrasion of the races 31 and 32 can be prevented. The life of the thrust ball bearing 30 can be extended.
About another structure and an effect, it is the same as that of the said 1st Embodiment.

  In addition, this invention is not limited to what was illustrated by said each embodiment, In the range which does not deviate from the summary of this invention, it can change suitably.

10 Compressor 30 Thrust ball bearing 31 Upper race (race)
31a Rolling surface 31b Rolling groove 32 Lower race (race)
32a Rolling surface 32b Rolling groove 33 Ball 34 Cage 35 Pocket 36 Inner circumferential groove (lubricating passage)
37 Peripheral groove (lubrication passage)
38 Lubrication groove (Lubrication passage)
39 Through hole (lubrication passage)
41 inner diameter surface 41a chamfer 42 outer diameter surface R2 radius of rolling groove D diameter of ball H depth of rolling groove

Claims (8)

A pair of races formed in an annular shape and spaced apart in parallel in the axial direction;
A plurality of balls arranged to roll freely between the pair of races;
A thrust ball bearing comprising: a cage disposed between the pair of races and holding the plurality of balls at a substantially equal interval in a circumferential direction;
The thrust ball bearing, wherein the cage includes at least one lubrication passage that penetrates in a plate thickness direction and communicates the upper and lower surfaces of the cage.   2. The thrust ball bearing according to claim 1, wherein the lubrication passage is a groove extending in a plate thickness direction of the cage, and is formed on at least one of an inner diameter surface and an outer diameter surface of the cage.   2. The thrust ball bearing according to claim 1, wherein the lubricating passage is a groove extending in a plate thickness direction of the cage, and is formed on an inner surface of a pocket that holds the ball of the cage.   The thrust ball bearing according to claim 1, wherein the lubrication passage is a through-hole penetrating the cage in a plate thickness direction.   5. The holder according to claim 1, wherein the cage has an inner diameter surface that is chamfered at both ends in the axial direction, or an inner diameter surface having an arcuate cross section that bulges inward in the radial direction. Thrust ball bearing described in At least one rolling groove in contact with the ball is provided in at least one of the pair of races,
The radius of the rolling groove is set to 60% or more of the diameter of the ball,
The thrust ball bearing according to claim 1, wherein a depth of the rolling groove is set to 60 μm or less.   The lubricant for lubricating each contact portion of the thrust ball bearing is supplied between an upper race disposed above the ball of the pair of races and the cage. The thrust ball bearing of any one of 1-6.   The thrust ball bearing according to any one of claims 1 to 7, wherein the thrust ball bearing is used in a compressor incorporated in a refrigerator-freezer or an air conditioner.

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