JP2013160291A - Thrust ball bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thrust ball bearing that can prevent a retainer and a shaft from being brough into contact with each other, thereby lengthening the lifetime of the bearing.SOLUTION: A thrust ball bearing 30 is formed in a circular-ring shape and includes a pair of races 31, 32 placed in parallel apart from each other in an axial direction, a plurality of balls 33 disposed to be free to roll between the pair of races 31, 32, a retainer 34 disposed between the pair of races 31, 32 with a plurality of balls 33 retained at approximately equal intervals, wherein at least one of rolling grooves 31a, 32a coming into contact with the balls 33 is installed on at least one of the pair of races 31, 32, an radius R of the rolling grooves 31a, 32a is set at 60% or more of a diameter D of the ball 33, and a depth H of the rolling grooves 31a, 32a is set at 60 μm or less.

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.

  Next, a conventional thrust ball bearing 50 used in a hermetic compressor such as a refrigerator or an air conditioner will be described with reference to FIG. The thrust ball bearing 50 is formed in an annular shape, and a pair of races 51 and 52 that are axially spaced apart from each other and arranged in parallel, and a plurality of balls 53 that are rotatably arranged between the pair of races 51 and 52. And a cage 54 that is disposed between the pair of races 51 and 52 and holds a plurality of balls at substantially equal intervals. The pair of races 51 and 52 are each formed of a flat plate. For this reason, the rolling surfaces 51a and 52a of the pair of races 51 and 52 with which the plurality of balls 53 are in contact are each formed in a flat shape.

  When the thrust ball bearing 50 supports the compressor shaft, the cage 54 is guided by the plurality of balls 53. However, since the rolling surfaces 51a and 52a are flat, the cage 54 is provided. Will come into contact with the shaft and be rotated around. At this time, normal rotation and revolution of the plurality of balls 53 are hindered by the interaction between the cage 54 and the plurality of balls 53, and slip occurs between the plurality of balls 53 and the rolling surfaces 51a and 52a. End up. Then, the occurrence of this slip leads to early wear of the races 51 and 52. As a result, noise and inefficiency during rotation of the bearing may be caused, and the reliability of the compressor may be lowered.

Thus, as a conventional technique, there is known a technique in which a plurality of balls are arranged in a staggered manner in a double row in the circumferential direction of the race so as to achieve high rigidity and to extend the life of the bearing (for example, see Patent Document 1). In addition, a predetermined axial clearance is provided between the shaft and the race, and this axial clearance is formed as a lubricating oil flow path, so that abundant lubricating oil is supplied to reduce noise during bearing rotation. In order to improve efficiency, there is known (for example, see Patent Document 2). In addition, the weight of one ball is m [g], the number of balls is Z [pieces], the rolling diameter of the balls is d [mm], the maximum rotation speed of the shaft is n [r / s], and the thrust ball bearing When the applied load in the direction of gravity is Fa [N], these values satisfy the relational expression of Fa> 2.0 × 10 ⁻³ · m · Z · d · n. What prevents wear is known (see, for example, Patent Document 3). In addition, an elastic support member that supports the thrust ball bearing in the direction of gravity is provided, which suppresses the contact load between the race and the ball when an external force is applied, thereby reducing noise and increasing efficiency during rotation of the bearing. What is shown is known (see, for example, Patent Document 4).

Japanese Patent Laid-Open No. 08-320018 JP 2010-255556 A JP 2008-121628 A JP 2010-101278 A

  However, any of the above-mentioned Patent Documents 1 to 4 complicates the structure, such as preparing a separate member or performing a new process, which may increase the manufacturing cost. In addition, none of the above Patent Documents 1 to 4 presents a specific solution in terms of preventing contact between the cage and the shaft.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a thrust ball bearing capable of preventing the contact between the cage and the shaft and extending the life of the bearing. is there.

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 cage for holding a plurality of balls at substantially equal intervals, wherein at least one rolling groove in contact with the ball is provided in at least one of the pair of races, and the radius of the rolling groove is The thrust ball bearing is characterized in that it is set to 60% or more of the diameter of the ball and the depth of the rolling groove is set to 60 μm or less.
(2) The thrust ball bearing according to (1), wherein the rolling groove is formed simultaneously when the race is pressed.
(3) The thrust ball bearing according to (1) or (2), which is used for a compressor incorporated in a refrigerator-freezer or an air conditioner.

  According to the thrust ball bearing of the present invention, at least one of the pair of races is provided with at least one rolling groove in contact with the ball, and the radius of the rolling groove is set to 60% or more of the diameter of the ball. Since the depth of the groove is set to 60 μm or less, the rolling position of the ball is regulated by the rolling groove, and the cage guided by the ball can be prevented from coming into contact with the shaft. Thereby, the slip between the ball and the race can be prevented and the wear of the race can be prevented, so that the life of the thrust ball bearing can be extended.

  Further, according to the thrust ball bearing of the present invention, the rolling groove is formed at the same time when the race is pressed, so that an increase in manufacturing cost can be suppressed.

It is sectional drawing explaining the compressor with which one 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. It is an expanded sectional view explaining the conventional thrust ball bearing.

  Hereinafter, a compressor using an embodiment of a thrust ball bearing according to the present invention will be described in detail with reference to the drawings.

  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. Are arranged between the upper and lower races 31 and 32, and a retainer 34 that holds the plurality of balls 33 at substantially equal intervals, and is loosely fitted to the main shaft portion 16. In the present embodiment, the upper and lower races 31, 32 and the plurality of balls 33 are made of metal. In addition, the refrigerant mixed with the lubricating component uses the bearing space between the upper and lower races 31 and 32 as a circulation path.

  The upper and lower races 31 and 32 are each formed of an annular flat plate, and rolling grooves 31a and 32a are formed on the surfaces of the upper and lower races 31 and 32 that are in contact with the balls 33, respectively. The radius (curvature) R of the rolling grooves 31a and 32a is set to 60% or more of the ball diameter D, and the depth H of the rolling grooves 31a and 32a is set to 60 μm or less. The rolling grooves 31a and 32a 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 provided with the rolling grooves 31a and 32a in contact with the balls 33, respectively, and the radius R of the rolling grooves 31a and 32a 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 31a and 32a is set to 60 μm or less, the rolling position of the ball 33 is regulated by the rolling grooves 31a and 32a. It is possible to prevent the cage 34 guided by 33 from coming into contact with the shaft 15. Thereby, the slip between the ball 33 and the races 31 and 32 can be prevented and the wear of the races 31 and 32 can be prevented, so that the life of the thrust ball bearing 30 can be extended.

  Moreover, according to the thrust ball bearing 30 of this embodiment, since the rolling grooves 31a and 32a are formed simultaneously when the races 31 and 32 are pressed, an increase in manufacturing cost can be suppressed.

In addition, this invention is not limited to what was illustrated to the said embodiment, In the range which does not deviate from the summary of this invention, it can change suitably.
For example, in the above-described embodiment, the case where the rolling grooves are in a single row has been illustrated, but the present invention is not limited thereto, and the raceway grooves may be in two or more rows.
Moreover, although the case where the rolling groove was formed in both upper and lower races was illustrated in the said embodiment, it is not limited to this, The rolling groove may be formed only in one side of the upper and lower race.

DESCRIPTION OF SYMBOLS 10 Compressor 30 Thrust ball bearing 31 Upper race 31a Rolling groove 32 Lower race 32a Rolling groove 33 Ball 34 Cage R Radius of rolling groove H Depth of rolling groove D Diameter of ball

Claims (3)

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 substantially equal intervals;
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,
A thrust ball bearing, wherein the rolling groove has a depth of 60 μm or less.   The thrust ball bearing according to claim 1, wherein the rolling groove is formed simultaneously when the race is pressed.   The thrust ball bearing according to claim 1 or 2, wherein the thrust ball bearing is used in a compressor incorporated in a refrigerator-freezer or an air conditioner.

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