JPH0587131A - Thrust ball bearing - Google Patents

Abstract

PURPOSE:To improve the lifetime, and facilitate the manufacture of a thrust ball bearing for supporting a revolution scroll member of a scroll compressor or the like impossibly to rotate by itself. CONSTITUTION:A pair of ring-shape track wheels 7, 7, in which a ball 8 is interposed respectively, are manufactured separately from a fixed frame 2 and a revolution scroll member 3, and are installed to these members 2, 3. Annular track grooves 11, in which the ball 8 is rolled respectively, are provided in each track wheel 7 at multiple parts in the circumferential direction. Each track groove 11 has a circular groove cross section, and a diameter (e) of a circumferential track along the bottom of the groove is nearly equal to a radius E of the revolution movement. Each ball 8 can be held by a holder, or a holder can be omitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thrust ball bearing which is used in a scroll compressor or the like to support an orbiting member such as an orbiting scroll member so as not to rotate.

[0002]

2. Description of the Related Art As shown in FIG. 11, a scroll compressor has a revolution scroll member 51 and a stationary scroll member 5.
2 is provided with spiral partition walls 53, 54, respectively, and both walls 53, 5 are provided.
The compression chamber 55 formed between the four
The compression operation is performed by changing the volume with the revolution of 1.

The revolving scroll member 51 revolves at a revolving radius E without rotating, and a ball 56 is interposed between the revolving scroll member 51 and the fixed frame 57 to prevent the rotation and support the revolution. I am letting you. The orbiting scroll member 51 and the fixed frame 57 are provided with a recess 58 for restraining the moving range of the ball 56, and the diameter of the recess 58 is substantially equal to the revolution radius E so that the ball 56 can roll in a circular orbit. Equally designed.

Instead of the recess 58, as shown in FIG. 12, an annular raceway groove 59 having an arc-shaped groove cross section is provided with the revolution radius R.
There has also been proposed one formed with an orbital diameter e equal to (see, for example, JP-A-55-155916).

[0005]

In the example of FIG. 11,
A large axial load acts on the revolution scroll member 51 due to the compressed gas pressure in the compression chamber 55, and this load is applied to the contact surface between the ball 56 and the bottom surface of the recess 58. However, since this contact state is a point contact due to the relationship between the sphere and the plane, the contact pressure per unit area is large, and therefore, there is a problem that wear and rolling fatigue are significant and the bearing life is shortened.

In the case of the example of FIG. 12, since the inner surface of the raceway groove 59 is arcuate, the contact area of the ball 56 with the raceway surface is large and the life is greatly improved. However, it is very difficult to directly process the annular raceway groove 59 having such an arcuate cross section on the orbiting scroll member 51 or the fixed frame 57, and therefore, there is a problem that productivity is poor and manufacturing cost is high. ..

An object of the present invention is to improve the bearing life and facilitate manufacturing of a thrust ball bearing that supports the revolution.

[0008]

In the thrust ball bearing of the present invention, a pair of ring-shaped races in which balls are interposed are manufactured separately from the revolution member and the fixing member, and are mounted on the revolution member and the fixing member. Is. Each raceway ring is provided with a plurality of annular raceway grooves for rolling balls interposed between the raceway rings at a plurality of positions in the circumferential direction. Each raceway groove has an arc-shaped groove cross section, and the diameter of a circumferential orbit along the groove bottom is substantially equal to the radius of the revolution motion.

In a thrust ball bearing according to a second aspect of the present invention, a ring-shaped bearing ring is provided with a plurality of raceway groove forming members in which each raceway groove is formed, and a plurality of spot facing portions in which these raceway groove forming members are embedded. And a ring-shaped bearing ring main body having

A thrust ball bearing according to a third aspect of the present invention is provided with a ring-shaped cage for holding the balls around the entire circumference in a state where the balls are not pulled out.

[0011]

According to this structure, when the revolving member is revolved, the rolling path of the ball interposed between the revolving member and the fixing member is restricted by the local annular raceway groove in the raceway of both members. Therefore, the revolution member is prevented from rotating. The axial load applied between the revolution member and the fixed member is
It acts on the contact surface between the ball and each race. At this time, since the inner surface of the raceway groove has an arcuate cross section, the contact area with the ball is large, and therefore, the life is long against wear and rolling fatigue. Although the raceway groove is an annular groove having an arcuate cross section, it can be easily manufactured because it is formed in a dedicated raceway ring separately from the revolution member and the fixing member.

When the ring-shaped bearing ring is divided into the raceway groove forming member and the bearing ring main body, it is not necessary to subject the ring-shaped bearing ring body to heat treatment, so that heat treatment deformation does not occur and accuracy is improved. Can be achieved.

When the retainer is provided, the ball can be incorporated into the bearing ring while being retained by the retainer. As a result, all balls will be installed in the same phase for each raceway groove of both races,
There is no need for ball phasing when assembling.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. This embodiment is an example applied to a scroll compressor, and a thrust ball bearing 1 includes a fixed frame 2 and a revolving scroll member 3 which serve as a fixing member and an orbiting member, respectively.
It is provided between and.

In the revolving scroll member 3, a cylindrical portion 3a protruding in the center is rotatably fitted to a drive shaft 4 via a bearing 5 such as a needle bearing, and the drive shaft 4 is a rotating shaft such as a motor ( It is provided eccentrically (not shown), and is revolved around an orbital center Q which is the axis of the rotating shaft with an orbital radius E.
Therefore, the revolving scroll member 3 revolves around the revolving center Q with the drive shaft 4 at the revolving radius E.

A fixed scroll member (not shown) facing the upper surface of the revolving scroll member 3 is provided in the housing 6 integral with the fixed frame 2, and these revolving scroll member 3 and the fixed scroll member are provided respectively. Between the spiral partition walls (not shown), the compression chamber of the scroll compressor is configured in the same manner as in the example of FIG.

The thrust ball bearing 1 comprises a pair of facing ring-shaped orbital rings 7, 7 mounted on the fixed frame 2 and the orbiting scroll member 3, and balls 8 interposed between the orbital rings 7, 7. Composed. The orbital rings 7, 7 are fitted into the annular orbital ring mounting groove 9 formed in the fixed frame 2 and the orbiting scroll member 3 in a fitted state. As shown in FIG. 2, the bearing ring 7 is provided with a rotation preventing protrusion 1 at a part in the circumferential direction.
By engaging the projection 10 with a recess (not shown) in the bearing ring mounting groove 9, the fixed frame 2 and the revolution scroll member 3 are angularly fixed.

On the facing surfaces of the pair of races 7, annular raceway grooves 11 for rolling the balls 8 are equally arranged at a plurality of positions in the circumferential direction. These raceway grooves 11 have a groove cross section formed in an arcuate cross section having a radius of curvature r slightly larger than the ball 8, and the diameter e of the circumferential orbit along the groove bottom is substantially equal to the revolution radius E of the revolution scroll member 3. Set equal.

The relationship between the diameter e of the circumferential track of the track groove 11 and the radius of curvature r of the groove cross section is appropriately set according to the application site. For this reason, in the annular raceway groove 11, there are cases where the inner peripheral edge 11a of the opening is continuous at one point as shown in FIG. 3 and cases where the inner peripheral edge 11a of the opening is separated as shown in FIG.

The operation of the above configuration will be described. The orbiting scroll member 3 makes an orbital motion with an orbital radius E by the drive of the drive shaft 4. At this time, the fixed frame 2 and the revolving scroll member 3 are engaged with each other through the balls 8 interposed between the orbital rings 7, 7, and the rolling range of the balls 8 is inside the annular raceway groove 11 which is localized. Therefore, the revolution of the revolution scroll member 3 is prevented. That is, each ball 8 moves along the orbiting wheel 7,
In the annular raceway groove 11 of 7, a diameter e equal to the revolution radius E
Rolling on a circular orbit. Therefore, the revolution scroll member 3 revolves with respect to the fixed frame 2 while always maintaining a constant angular relationship, and the compression operation of the scroll compressor is performed by such an operation.

The revolution scroll member 3 is driven by the compressed gas pressure.
A large axial load is applied to the bearing, but this axial load is received by the contact surface between the ball 8 and the bearing rings 7, 7. At this time, since the inner surface of the raceway groove 11 is formed in an arcuate cross section, the contact area with the balls 8 is large, and therefore wear and rolling fatigue are less likely to occur and the bearing life is improved.

The raceway groove 11 is an annular groove having an arcuate cross section that is relatively difficult to machine. However, since it is formed on the raceway rings 7, 7 which are ring-shaped parts having a simple shape, the orbiting scroll member 3 having a complicated shape and the like. Compared to the case where the raceway groove 11 is directly machined in the fixed frame 2, it can be machined more easily.

The raceway groove 11 may be formed by carving out a steel plate raceway material, but in addition to this, a forming method such as press working or sintering may be adopted as follows.

In the case of press working, the recessed shape of the raceway groove 11 is worked on a ring-shaped raceway material made of steel plate by press working or forging, and then, as shown in the cross section in FIG. Surface hardening treatment such as carburizing or induction hardening. For finishing the inner surface of the raceway groove 11, a diameter slightly larger than that of the ball 8 used as a bearing (raceway groove 1
A polishing ball having a radius corresponding to the design curvature of the groove cross section of No. 1) is used, and the ball and the lapping agent are arranged in the raceway groove 11, and the pair of opposed raceways 7 are revolved in the same revolution as in use. Sliding while revolving with radius E. This allows
The raceway groove 11 can be finished into a predetermined cross-sectional shape.

In the case of the processing method by sintering, the bearing ring 7 is formed into a shape having the bearing groove 11 by using a ferrous sintered alloy. Then, carburizing the inner surface of the raceway groove 11,
Increase hardness. Finishing after carburization is performed by sliding with a polishing ball as in the case of the above-mentioned press. As described above, by adopting the press or sintering molding, the workability is improved as compared with the shaving, and the manufacturing cost can be reduced.

FIG. 6 shows another embodiment. In this example, the ring-shaped raceway ring 7 is provided with a plurality of raceway groove forming members 12 in which each raceway groove 11 is formed, and a ring-shaped raceway in which a counterbore portion 13 in which these raceway groove forming members 12 are embedded is provided. Wheel body 1
4 and. As the bearing ring forming member 12, generally used bearing steel or the like is used, and not only the surface but also the core portion is subjected to a hardening treatment by so-called soaking. Various materials can be used for the bearing ring main body 14 because no surface hardening treatment is required. For example, an aluminum alloy such as hard alumite, an aluminum casting, or the like can be adopted, which makes it possible to easily manufacture the bearing ring main body 14 having the spot facing portion 13.

In the case of this construction, since the heat treatment for hardening the surface of the bearing ring main body 14 is not required, unlike the case where the entire bearing ring 7 is heat treated as in the above-mentioned embodiments, the ring shape is not warped. No large heat treatment deformation occurs.
Therefore, the height accuracy of the raceway groove 11 of each part improves. In particular, when the width B is narrower than the outer diameter of the bearing ring 7, the above-mentioned problem of ring-shaped warpage easily occurs. In such a case, this embodiment is effective.

As shown in FIG. 7, the bearing ring forming member 12 may be formed with a flat surface portion 12a on the outer periphery thereof, which can prevent rotation in the counterbore recess 13 and prevent wear of the fitting surface. ..

8 and 9 show still another embodiment. In this example, a ring-shaped cage 15 for holding the balls 8 around the entire circumference is provided. The cage 15 has a structure similar to that of a cage provided in an ordinary flat seat type thrust ball bearing, and is capable of retaining the balls 8 in respective pockets in a retaining state. Although the material of the cage 15 is a press-formed product of an iron plate in this example, it may be a resin or brass casting.

By providing the retainer 15 in this manner, the work of assembling the ball 8 is facilitated. That is, in this type of thrust ball bearing, it is necessary to match the phases of the balls 8 with all the raceway grooves 11 of both races 7, 7 at the time of assembly. Therefore, if the balls 8 are incorporated one by one, Phase alignment work is difficult. However, when the retainer 15 is provided as in this embodiment, by incorporating the balls 8 in the state of being retained by the retainer 15, all the balls 8 are incorporated in the orbit grooves 11 in the same phase. Become. Therefore, the phase matching work is unnecessary and the assembling work becomes easy.

The retainer 15 can be provided in each of the above embodiments. For example, in an embodiment in which each raceway groove 11 of FIG. 6 is provided in a separate raceway groove forming member 12, as shown in FIG. 10, a retainer 15 may be provided in the same manner as described above.

[0032]

In the thrust ball bearing of the present invention, the ball is guided by the annular raceway groove having an arcuate cross section, so that the contact area between the ball and the raceway surface is large, and therefore, between the revolution member and the fixing member. The bearing pressure is reduced against a large axial load acting, and the life of the bearing can be significantly improved.
In addition, since the ring-shaped raceway that forms the raceway groove is manufactured separately from the revolution member and the fixed member and mounted on these revolution members, etc., it is easy to machine even though the raceway groove is an annular groove with an arc-shaped cross section. There is an effect that the cost can be reduced.

In the thrust ball bearing of the second aspect, the ring-shaped bearing ring is composed of a plurality of raceway groove forming members each having each raceway groove formed therein and a ring-shaped bearing ring main body having a spot facing portion. The accuracy can be improved without causing a large heat treatment deformation.

Since the thrust ball bearing of claim 3 is provided with the retainer for holding the balls around the entire circumference in a state where the balls are not pulled out, when the balls are incorporated in the bearing ring, they may be incorporated in the retainer. it can. Therefore, all the balls of both races are assembled in the same phase with respect to each raceway groove, and the phase matching work is unnecessary and the assembling work is simplified.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state where a thrust ball bearing according to an embodiment of the present invention is incorporated in a scroll device.

FIG. 2 is a perspective view of the bearing ring.

FIG. 3 is a partially enlarged sectional view of a modified example of a bearing ring.

FIG. 4 is a partially enlarged cross-sectional view of another modified example of the bearing ring.

FIG. 5 is a partial enlarged cross-sectional view of still another modified example of the bearing ring.

FIG. 6 is a partially exploded perspective view of another embodiment of the present invention.

FIG. 7 is a partial plan view of a bearing ring according to still another embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a state where a thrust ball bearing according to still another embodiment of the present invention is incorporated in a scroll device.

FIG. 9 is a perspective view of the retainer.

FIG. 10 is a partial sectional view showing still another embodiment of the present invention.

FIG. 11 is a partial cross-sectional view showing the relationship between a conventional thrust ball bearing and a scroll device.

FIG. 12 is a partial cross-sectional view of another conventional example.

[Explanation of symbols]

1 ... Thrust ball bearing, 2 ... Fixed frame (fixed member),
3 ... Revolution scroll member (revolution member), 4 ... Drive shaft, 7
... raceway ring, 8 ... ball, 11 ... raceway groove, 12 ... raceway groove forming member, 13 ... counterbore part, 14 ... raceway body, 15 ... cage

Claims (3)

[Claims] 1. A pair of ring-shaped orbital rings that are respectively mounted on orbiting members and fixed members that orbit each other and face each other in the axial direction, and are interposed between the two orbiting rings at a plurality of circumferential positions of these orbital rings. An annular raceway groove for rolling each formed ball is provided. Each of these raceway grooves has an arc-shaped groove cross section, and the diameter of the circumferential orbit along the groove bottom is substantially equal to the radius of the revolution motion. Ball bearings. 2. A ring-shaped bearing ring having a plurality of raceway groove forming members in which the respective raceway grooves are formed and a plurality of counterbore portions in which these raceway groove forming members are embedded. The thrust ball bearing according to claim 1, wherein the thrust ball bearing comprises a main body. 3. The thrust ball bearing according to claim 1, further comprising a ring-shaped retainer for retaining the balls around the entire circumference in a state where the balls are not pulled out.