JP3737860B2 - Thrust ball bearing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thrust ball bearing that is interposed between two members that perform eccentric rotational movement between each other, such as a turning scroll member and a stationary scroll member in a scroll compressor.
[0002]
[Prior art]
For example, as shown in FIG. 5, the scroll compressor is provided with spiral partition walls 11b and 12b on the orbiting scroll member 11 and the stationary scroll member 12, respectively, and a compression chamber P formed between the spiral partition walls 11b and 12b. The fluid in the compression chamber P is compressed by changing the volume in accordance with the eccentric rotation of the orbiting scroll member 11 with respect to the stationary scroll member 12.
[0003]
The axis of the orbiting scroll member 11 and the axis of the drive motor 15 are eccentric by an eccentric amount e. When the output shaft 15a of the drive motor 15 rotates, the orbiting scroll member 11 rotates eccentrically with an orbiting radius equal to the eccentric amount e. To do. At this time, the orbiting scroll member 11 is subjected to a force to rotate it, and a thrust load accompanying a fluid compression operation is applied. Therefore, in order to prevent the orbiting scroll member 11 from rotating and to support the thrust load, the orbiting scroll member 11 and the stationary scroll member 12 (in the configuration shown in the figure, the stationary frame 13 fixed to the stationary scroll member 12). A thrust ball bearing 14 is interposed therebetween.
[0004]
As shown in an enlarged view in FIG. 7, the thrust ball bearing 14 includes a pair of race rings 14a and 14b and a plurality of balls 14c interposed between the raceway surfaces 14a1 and 14b1 of the race rings 14a and 14b. . The track rings 14a and 14b are fixed to the mounting portions 11a and 13a of the orbiting scroll member 11 and the stationary frame 13 facing each other in the axial direction.
[0005]
As shown in FIG. 6, the race rings 14a and 14b are rings of the same shape and size, and a plurality of raceway surfaces 14a1 (14b1) are formed on the same circumference on one end face thereof. Each raceway surface 14a1 (14b1) has an annular shape, and its cross-sectional shape has an arc shape. The balls 14c arranged on the raceway surfaces 14a1 (14b1) roll on the pitch circle PCD of the raceway surface 14a1 (14b1) as the orbiting scroll member 11 rotates eccentrically. The diameter d of the pitch circle PCD of the raceway surface 14a1 (14b1) is equal to the eccentricity e.
[0006]
[Problems to be solved by the invention]
In the conventional thrust ball bearing 14, the pair of race rings 14a and 14b have the same shape and the same dimensions, and the groove curvatures of the raceway surfaces 14a1 and 14b1 are the same. The reason why the raceway surfaces 14a1 and 14b1 have a groove curvature is to reduce the contact surface pressure with the ball 14c and to improve the service life.
[0007]
However, there may be a deviation in the positional relationship between the races 14a and 14b due to an attachment error or the like, and a function capable of absorbing such a positional deviation is required.
[0008]
The present invention is intended to provide a configuration capable of absorbing the positional deviation between the races while taking into account the basic requirements of reducing the contact surface pressure and ensuring the bearing function.
[0009]
[Means for Solving the Problems]
The thrust ball bearing of the present invention is formed at a plurality of locations of a pair of bearing rings that are respectively fixed to mounting portions opposite to each other in the axial direction of two members that perform eccentric rotational motion between each other. A pair of raceways having a groove surface with a large groove curvature and a raceway surface with a small groove curvature, and the pair of raceways are mutually connected. The groove curvatures of the opposed raceway surfaces are different from each other in the circumferential direction .
[0010]
The thrust ball bearing of the present invention includes a pair of raceways arranged opposite to each other in the axial direction, and balls interposed between annular raceway surfaces formed at a plurality of locations of the raceways . The raceway is a raceway of the same shape having a raceway surface having a large groove curvature and a raceway surface having a small groove curvature, and the pair of raceways are displaced in the circumferential direction so that the groove curvatures of the opposed raceway surfaces are It is characterized by being different from each other .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment when the present invention is applied to a thrust ball bearing for a scroll compressor will be described.
[0013]
FIG. 1 shows a peripheral portion of a thrust ball bearing 4 in a scroll compressor as shown in FIG. A pair of race rings 4a, 4b of a thrust ball bearing 4 are mounted on mounting portions 1a, 3a opposite to each other in the axial direction of the orbiting scroll member 1 and the stationary frame 3 (the stationary frame 3 is fixed to the stationary scroll member 2). Balls 4c are respectively disposed between a plurality of raceway surfaces 4a1 and 4b1 fixed to each other and formed on the pair of raceways 4a and 4b. When the orbiting scroll member 1 rotates eccentrically with an orbiting radius equal to the eccentric amount e with respect to the stationary scroll member 2, the volume of the compression chamber P formed between the spiral partition walls 1b and 2b changes, and the fluid The compression operation is performed. The thrust ball bearing 4 serves to support the thrust load while preventing the orbiting scroll member 1 from rotating when such a compression operation is performed.
[0014]
As shown in an enlarged view in FIG. 1B, in this embodiment, the mounting portions 1a and 3a are both stepped, and the inner periphery 4a2 of the turning-side raceway 4a is connected to the shoulder 1a1 of the mounting portion 1a. The outer periphery 4b2 of the stationary raceway ring 4b is fitted to the shoulder portion 3a1 of the mounting portion 3a, and appropriate anti-rotation means is applied.
[0015]
The raceway ring 4a (4b) is formed, for example, by pressing from a steel plate material, and a plurality of raceway surfaces 4a1 (4b1) are formed on the same circumference on one end face thereof. Each raceway surface 4a1 has an annular shape, and the ball 4c disposed on each raceway surface 4a1 rolls on the pitch circle of the raceway surface 4a1 (4b1) as the orbiting scroll member 1 rotates eccentrically.
[0016]
As shown in FIG. 2 in an enlarged manner, the thrust ball bearing 4 of this embodiment is different from the conventional configuration in that the groove curvature (curvature radius) Ra of the raceway surface 4a1 of one raceway ring, for example, the raceway ring 4a on the turning side, is set. The other raceway ring, for example, is in a point larger than the groove curvature (curvature radius) Rb of the raceway surface 4b1 of the stationary raceway ring 4b (Ra> Rb). The magnitude relationship of the groove curvature may be Ra <Rb.
[0017]
As shown in FIG. 3, when a positional deviation α occurs between the turning-side raceway ring 4a and the stationary-side raceway ring 4b due to an attachment error or the like, the raceway ring 4a having a large groove curvature on the raceway surface 4a1. The position shift is absorbed by. The diameter of the pitch circle PCD of the raceway surface 4b1 is equal to the eccentricity e.
[0018]
As shown in FIG. 4, the groove curvature of the raceway surface 4a1 of one raceway, for example, the raceway 4a on the turning side, may be infinite and flat.
[0019]
In the above, the embodiment in which a different die is used for press working from a steel plate material has been described for each of the one raceway ring 4a and the other raceway ring 4b. However, the embodiment is not necessarily limited to this. The same race may be used for both sides. For example, as shown in FIG. 8A, a raceway surface 24a1 having a large groove curvature and a raceway surface 24a2 having a small groove curvature are alternately formed on the same circumference of one raceway ring 24a, and a pair thereof may be used. Good. In this case, the pair of race rings 24a are shifted from each other in the circumferential direction by one raceway surface 24a1 (24a2) so as to face each other, and the inner circumference 24a3 of the turning raceway 24a is mounted as shown in FIG. The shoulder part 1a1 of the part 1a is fitted, and the outer periphery 24a4 of the stationary ring 24 is fitted to the shoulder part 3a1 of the mounting part 3a. Then, in each phase in the circumferential direction, the raceway surface 24a1 having a large groove curvature and the raceway surface 24a2 having a small groove curvature are opposed to each other. The groove curvature of the raceway surface 24a1 of the raceway ring 24a is the same as the groove curvature Ra of the raceway surface 4a1, and the groove curvature of the raceway surface 24a2 is the same as the groove curvature Rb of the raceway surface 4b1 (Ra>). Rb). Further, the diameter of the pitch circle PCD of the raceway surface 24a2 is equal to the eccentricity e shown in FIG. However, in FIG. 8, for the convenience of explanation, the raceway surface 24a1 is exaggerated slightly larger than the raceway surface 24a2. In addition, since other various structures are the same as that of the thrust ball bearing 4 shown in FIG. 1, description is simplified using the same code | symbol suitably.
[0020]
Since this bearing ring 24a uses the same shape as a pair, the number of parts can be reduced and the manufacturing cost can be reduced as compared with the embodiment in which the bearing rings 4a and 4b having different shapes are mounted on the turning side and the stationary side, respectively. Can be greatly reduced.
[0021]
Thus, by devising the arrangement of the raceway surfaces 24a1 and 24a2 in the pair of raceways 24a and 24a, using one type (same shape) of raceways 24a and 24a, two types (different shapes) of raceways 4a. , 4b, the positional deviation of the pair of race rings 24a, 24a due to an attachment error or the like can be reliably absorbed.
[0022]
Alternatively, as shown in FIG. 8B, a raceway surface 34a1 having a large groove curvature and a raceway surface 34a2 having a small groove curvature may be alternately formed on the same circumference of one raceway ring 34a. The track ring 34a also has the same functions and effects as the track ring 24a.
[0023]
Further, as shown in FIG. 8 (c), a raceway surface 44a1 having a large groove curvature and a raceway surface 44a2 having a small groove curvature are continuously formed on the same circumference of one raceway ring 44a by half. Also good.
[0024]
The present invention is not limited to thrust ball bearings for scroll compressors, and can be applied to thrust ball bearings that support thrust loads by interposing between two members that perform eccentric rotational motion between each other.
[0025]
【The invention's effect】
As described above, the present invention, since opposite the raceway surface groove curvature of the pair of bearing rings is so different from each other, Ru positional deviation between raceway cross is absorbed by a large raceway surface of the groove curvature At the same time, proper rolling of the ball can be ensured by the raceway surface having a small groove curvature . Therefore, according to the present invention, it is possible to provide a thrust ball bearing that can absorb the positional deviation between the race rings while satisfying the basic requirements of reducing the contact surface pressure and ensuring the bearing function.
[0026]
In addition , a pair of raceways having the same shape in which a raceway surface having a large groove curvature and a raceway surface having a small groove curvature are formed in a predetermined pattern are used as a pair, and the pair of raceways are shifted from each other in the circumferential direction to face each other. Therefore , it is possible to reduce the manufacturing cost by using only one type of track ring .
[Brief description of the drawings]
FIG. 1 is a cross-sectional view (FIG. A) showing a peripheral portion of a thrust ball bearing in a scroll compressor according to an embodiment, and an enlarged cross-sectional view (FIG. B) showing the vicinity of a thrust ball bearing.
FIG. 2 is an enlarged cross-sectional view showing a periphery of a raceway surface of a thrust ball bearing according to an embodiment.
FIG. 3 is an enlarged cross-sectional view showing the periphery of the raceway surface of the thrust ball bearing according to the embodiment.
FIG. 4 is an enlarged sectional view showing a periphery of a raceway surface of a thrust ball bearing according to the embodiment.
FIG. 5 is a perspective view showing an embodiment of a scroll compressor.
FIG. 6 is a plan view showing a track ring.
FIG. 7 is a sectional view showing a conventional thrust ball bearing.
FIGS. 8A, 8B, and 8C are plan views showing other embodiments of the raceway, respectively.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Orbiting scroll member 1a Mounting part 2 Stationary school member 3 Static frame 3a Mounting part 4 Thrust ball bearing 4a Track ring 4a1 Track surface 4b Track ring 4b1 Track surface 4c Ball 24a Track ring 24a1 Track surface 24a2 Track surface 34a Track ring 34a1 Track surface 34a2 Track surface 44a Track ring 44a1 Track surface 44a2 Track surface

Claims (2)

Two members that perform eccentric rotational movement between each other are interposed between a pair of race rings fixed to mounting portions facing each other in the axial direction and annular raceway surfaces formed at a plurality of locations of these race rings. With a ball,
The pair of races is a raceway of the same shape having a raceway surface with a large groove curvature and a raceway surface with a small groove curvature, and the pair of race rings are shifted in the circumferential direction with respect to each other. A thrust ball bearing characterized in that the groove curvatures are different from each other . A pair of raceways arranged opposite to each other in the axial direction, and balls interposed between annular raceway surfaces formed at a plurality of locations of these raceways,
The pair of races is a raceway of the same shape having a raceway surface with a large groove curvature and a raceway surface with a small groove curvature, and the pair of race rings are shifted in the circumferential direction with respect to each other. A thrust ball bearing characterized in that the groove curvatures are different from each other .

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