JP2003329040A - Eccentric thrust bearing and double conical rollers therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide double conical rollers for an eccentric thrust bearing which materializes prevention of occurrence of an edge load, and improvement of withstand load performance and durability. <P>SOLUTION: A continuous crowning is provided to two conical surfaces of the double conical rollers 13 like a bead on an abacus. In no-load condition, the respective conical surfaces of the double conical rollers 13 are brought into contact closer to the respective peak sides P of the double conical rollers 13 than the normal X passing through the center of gravity G of the double conical rollers 13 with respect to the races 11, 12. By so doing, the rotation shaft S of the double conical rollers 13 is tilted by making the center of gravity G as the center during the activation of the thrust load. The tilt separates the respective peak sides of the double conical rollers 13 from the race 11, 12 to bring the major diameter side of the double conical rollers 13 close to the races 11, 12. Therefore, respective peak sides of the double conical rollers 13 and the major diameter side do not abut the edge with respect to the races 11, 12. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a double tapered roller for an eccentric thrust bearing and an eccentric thrust bearing.

[0002]

2. Description of the Related Art A scroll compressor, for example, has an orbiting scroll member which makes an eccentric orbiting motion with respect to a frame. An eccentric thrust bearing is used to smooth the eccentric orbiting motion of the orbiting scroll member.

As an example of the eccentric thrust bearing, there is, for example, Japanese Unexamined Patent Publication No. 10-184676. In this eccentric thrust bearing, so-called double tapered rollers such as abacus balls are arranged so that they can rotate and rotate one by one in a circular raceway groove provided at several places on the inner surface of each pair of races. It has become. The above tapered rollers have an apex angle of 90 degrees and are substantially square as viewed from the side.

[0004]

In the above-mentioned eccentric thrust bearing, it is preferable to increase the contact area between the tapered rollers and the race in order to reduce the maximum contact surface pressure.

For that purpose, the length from the apex of the conical surface of both tapered rollers to the large diameter portion may be increased. However, in that case, it is necessary to increase the facing distance between the pair of races, which increases the axial dimension of the eccentric thrust bearing.

Therefore, in order to increase the contact area of both tapered rollers with respect to the race without increasing the facing distance between the pair of races, the apex angle of both tapered rollers is set to be larger than 90 degrees or smaller than 90 degrees. It is considered that the shape of both tapered rollers is substantially rhomboidal when viewed from the side surface by doing so.

That is, when the apex angle of both tapered rollers is set to be larger than 90 degrees, the contact length in the radial direction of both tapered rollers with respect to the race becomes longer than that when the apex angle is set to 90 degrees. . In addition, since the circumferential curvature of each conical surface of both tapered rollers is larger than that in the case where the apex angle is set to 90 degrees, the contact length of both tapered rollers in the circumferential direction against the race under the action of thrust load. However, it is longer than when the apex angle is set to 90 degrees.

On the other hand, when the apex angle of both tapered rollers is set smaller than 90 degrees, the radial contact length of the two tapered rollers with respect to the race becomes longer than when the apex angle is set to 90 degrees. . In this case, since the circumferential curvature of each conical surface of both tapered rollers is smaller than that in the case where the apex angle is set to 90 degrees, the contact of the both tapered rollers with the race in the circumferential direction during the action of the thrust load. The length is shorter than when the apex angle is set to 90 degrees. Therefore, the total contact area is smaller than when the apex angle of both tapered rollers is set larger than 90 degrees, but the apex angle is 9
It can be made larger than when it is set to 0 degrees.

However, as described above, when the apex angle of both tapered rollers is set to be larger than 90 degrees or set to be smaller than 90 degrees, the first conical surface and the second conical surface of both tapered rollers become However, since the races are separated from each other in the radial direction, the moment that acts with the center of gravity of both tapered rollers as the origin when the thrust load is applied becomes larger than when the apex angle of both tapered rollers is set to 90 degrees. Therefore, the inclination of the rotation axis of both tapered rollers tends to be larger than when the apex angle of both tapered rollers is set to 90 degrees, so that edge loading occurs on the apex side or the large diameter side of both tapered rollers, Local parts of both tapered rollers easily seize in a short period of time.

[0010]

On the other hand, the applicant of the present invention considered crowning two conical surfaces of both tapered rollers. However, the applicant of the present application has found that it is necessary to specify the contact state between the tapered rollers and the race in the process of performing the crowning.

That is, when the crowning is performed, both the tapered rollers tend to tilt when a load is applied. However, due to the increase in slip between the tapered rollers and the race due to the tilt, and the abnormal whirling of the tapered rollers. There is concern about problems such as increased vibration, seizure of the contact part due to increased local pressure, increased rotation torque due to these, and shortened life. However, by appropriately adjusting the shape of the crowning, the problem is effectively solved. It was found that it can be reduced to.

The double tapered roller for the eccentric thrust bearing of the present invention has such a shape that the large diameter portions of the two cones are joined together, and the two conical surfaces are rolling surfaces. Each of the conical surfaces is provided with a continuous crowning, and in the unloaded state, each of the conical surfaces makes contact with the race on each apex side of both tapered rollers with respect to the vertical line passing through the center of gravity of both tapered rollers. To be done.

The shape in which the large-diameter portions of the two conical bodies are joined together means that the chamfered shape is a cylindrical shape in which both end surfaces are conical.
Meaning with two conical surfaces.

In such a contact state, when the thrust load is applied, the rotating shafts of both tapered rollers are tilted about the center of gravity by the moment acting with the center of gravity of both tapered rollers as the origin. This inclination is such that the apex sides of both tapered rollers are separated from the race and the large diameter sides of both tapered rollers are brought closer to the race. As a result, the maximum contact surface pressure between the tapered rollers and the race is reduced. Further, since the apex side and the large diameter side of the both tapered rollers due to the tilting of the both tapered rollers do not come into edge contact with the race, it is possible to prevent the occurrence of edge load.

The apex angle of each conical surface can be set larger than 90 degrees. In this case, the length from the apex of the conical surface of both tapered rollers to the large diameter portion becomes as long as possible, and the circumferential curvature becomes large. As a result, when the thrust load is applied, the contact range between the tapered rollers and each race is expanded as much as possible in the radial direction and the circumferential direction of the race, and the maximum contact surface pressure is reduced.

Further, the vertices of both tapered rollers can be chamfered. In this case, it is possible to reliably prevent each vertex of both tapered rollers from contacting the race.

The eccentric thrust bearing of the present invention is arranged between a revolving member which makes an eccentric revolving motion and a fixed member which axially opposes the revolving member. The race is composed of a pair of two annular plates. And a plurality of tapered rollers. Each race is provided separately on the facing surfaces of the two members. Both conical rollers are shaped so that the large diameter portions of the two conical bodies are joined together, and the two conical surfaces are rolling surfaces that come into contact with the races so that they can rotate and rotate. The two conical surfaces of the both tapered rollers are provided with continuous crowning, and in the unloaded state, each conical surface is more conical with respect to each race than the perpendicular line passing through the center of gravity of the both conical rollers. Contact is made at each vertex of the rollers.

In this case, as described above, the maximum contact surface pressure between the tapered rollers and the race is lowered. Further, the edge contact between both tapered rollers is eliminated, and the occurrence of edge load is prevented. Therefore, the durability of the bearing is improved and the life is extended.

The eccentric thrust bearing is also
Similarly to the above, the apex angle of each conical surface of both tapered rollers may be set to be larger than 90 degrees, or chamfering may be provided at each apex of both tapered rollers.

[0020]

1 to 10 show one embodiment of the present invention. In the figure, 1 is a scroll compressor.

This scroll compressor 1 has a generally well-known structure. For example, a rotary shaft 2 such as a motor shaft is driven to rotate, and an orbiting scroll member 3 is connected to an eccentric shaft portion 2a at the shaft end thereof. The eccentric orbiting motion of the fluid changes the volume of the compression chamber between the orbiting scroll member 3 and the fixed scroll member 4 to compress the fluid in the compression chamber.

The rotary shaft 2 is 2 with respect to the frame 5.
It is supported via two radial type rolling bearings 6 and 7. Further, the eccentric shaft portion 2a of the rotary shaft 2 is fitted and attached to the cylindrical boss portion 3a of the orbiting scroll member 3 via a radial type rolling bearing 8. Further, between the orbiting scroll member 3 and the frame 5, an eccentric thrust bearing 10 for supporting the eccentric orbiting motion of the orbiting scroll member 3 is arranged.

The eccentric thrust bearing 10 includes a pair of annular races 11 and 12 and a plurality of tapered rollers 13.

The upper race 11 is fixedly attached to the lower surface of the orbiting scroll member 3. The lower race 12 is fixedly attached to the upper surface of the frame 5. Due to this relationship, the upper race 11
Since the eccentric orbiting motion is performed integrally with the orbiting scroll member 3,
Hereinafter referred to as the movable race. On the other hand, since the lower race 12 is fixed to the frame 5 and is immovable, it is hereinafter referred to as a fixed race. Both races 11, 1
Although not shown, in order to fix 2 to the orbiting scroll member 3 and the frame 5, for example, both can be provided by arranging concavities and convexities and fitting them together.

On both races 11 and 12, circular raceway grooves 14 and 1 having a circular plane shape and a required depth at several places on the circumference.
5 is formed. Round rod-shaped pins 16 are provided at three locations on the fixed-side race 12 that are equally spaced around the circumference. Also,
Circular through holes 17 into which the pins 16 are inserted with a predetermined gap are provided at three positions on the movable race 11 corresponding to the pins 16. The pin 16 and the through hole 17 prevent the movable side race 11 from rotating and restrict the eccentric turning range.

The plurality of tapered rollers 13 are formed by the races 11,
It is interposed between each of the twelve circular raceway grooves 14, 15.
The tapered rollers 13 are formed in a substantially rhombic shape when viewed from the side.

The races 11 and 12, the tapered rollers 13 and the pins 16 described above are made of a metal material such as JIS standard SUJ2 or SAE standard 5120 which is carburized and hardened as required, or ceramics. It is formed.

As the above ceramic material, for example, silicon nitride is mainly used, yttria and alumina are used as a sintering aid, and also aluminum nitride, titanium oxide, and spinel are appropriately used, and alumina, silicon carbide, zirconia, Examples include aluminum nitride. Specifically, yttria is 1.5 to 5.5% by weight, aluminum nitride is 1 to 2% by weight, alumina is 2 to 4.5% by weight, and titanium oxide is 0.5% by weight.
It is preferable to use a ceramic having a content of ˜1.0 wt% and the rest being silicon nitride.

Next, the operation will be described. That is, FIG.
As shown in (a) to (d), the center points O of the orbiting scroll member 3 and the movable race 11 are O1, O2, O.
When it is eccentrically swung to 3, O4, both tapered rollers 13 are guided by the inner peripheral walls of the circular raceway grooves 14 and 15 as shown by the arrows in FIG. Rotating and rotating to orbit scroll member 3 and movable race 1
1 supports an eccentric turning motion.

At this time, the inner peripheral wall surface of the through hole 17 of the movable race 11 is slidably guided to the outer peripheral surface of the round bar pin 16 of the fixed race 12, so that the orbiting scroll member 3 and the movable side are movable. Because it prevents the rotation of Race 11,
While controlling the eccentric turning range of the turning scroll member 3 and the movable side race 11, the eccentric turning locus is stabilized, and
The rotating and rotating motion of both tapered rollers 13 becomes smooth.

In this embodiment, crowning is provided on the two conical surfaces of the two tapered rollers 13, and
The shape of this crowning is devised.

Specifically, as shown in FIG. 8, the apex angle θ of each conical surface of both tapered rollers 13 is set to 150 degrees. The apex angle θ is set in the shape before the crowning is provided on both tapered rollers 13 (see the broken line in FIG. 8). As a result, the length from the apex of each conical surface of both tapered rollers 13 to the large diameter portion becomes as long as possible, and the circumferential curvature becomes large. Race 1 is the contact area with each race 11 and 12
Spread as much as possible in the radial and circumferential directions of 1 and 12.

Further, continuous crowning is provided on each conical surface of both tapered rollers 13. The crowning is set to a single radius of curvature in this embodiment. As a result, the generatrix shape of each conical surface of both tapered rollers 13 is a convex curved surface having a single radius of curvature. In addition,
In the figure, the curvature of the crowning is exaggerated.

The center of curvature O of the crowning is larger than the perpendicular line X passing through the center of gravity G of the tapered rollers 13 with respect to the tapered rollers 13 with each other.
It is located on the apex side of. As a result, in the unloaded state, the conical surfaces of the two tapered rollers 13 have the respective races 11, 1
2 is contacted on the apex side of both tapered rollers 13 with respect to the perpendicular line X. Let this contact point be P.

When such a crowning is formed, when a thrust load acts, a moment M acts in the clockwise direction in FIG. 8 with the center of gravity G of both tapered rollers 13 as the origin. Due to this moment M, the rotation axis S of both tapered rollers 13 tilts in the clockwise direction in FIG. 8 about the center of gravity G. Due to this inclination, as shown in FIG. 9, each apex side of both tapered rollers 13 is separated from races 11 and 12, and both tapered rollers 13 are separated.
The larger-diameter side of the race approaches the races 11 and 12. As a result, both the apex side and the large diameter side of both tapered rollers 13 do not hit the edges of the races 11 and 12. At this time, both tapered rollers 1 for the races 11 and 12
As shown in FIG. 9, the contact areas of the races 3 are the races 11, 1
2 Oval shape spread in the radial and circumferential directions.

As shown in FIG. 8, both tapered rollers 13
Contact point P of both tapered rollers 13 from a vertical line X passing through the center of gravity G of
The distance u to L is the length of BC (L is effective for both tapered rollers, where C is the intersection of a perpendicular line Y passing through one apex A of both tapered rollers 13 and a ridge line including the other vertex B). Contact length), if the apex angle is 90 °, 120 °, 150 °, it is about (1/100) · L, and the apex angle is 6
In the case of 0 degree, it is preferable to set it to about (0.3 / 100) · L. By setting the distance u in this way, the inclination of both tapered rollers 13 can be almost eliminated.

By the way, as shown by the chain double-dashed line in FIG. 10, when the center of curvature O1 of the crowning is arranged on the perpendicular line X passing through the center of gravity G of both the tapered rollers 13, the two tapered rollers are in an unloaded state. Each conical surface of 13 is each race 1
1, 1 and 12 are brought into contact with each other at P1 on the perpendicular line X. In this case, even if the thrust load acts,
The moment M with the center of gravity G of both tapered rollers 13 as the origin is
It does not work in theory.

As shown by the alternate long and short dash line in FIG. 10, the center of curvature O2 of the crowning is set to the center of gravity G of both tapered rollers 13.
When arranged on the larger diameter side of both tapered rollers 13 with respect to the perpendicular line X passing through, the respective conical surfaces of both tapered rollers 13 with respect to the races 11 and 12 in the unloaded state are both tapered rollers more than the perpendicular line X. P2 on the large diameter side of 13 comes into contact.
In this case, when the thrust load acts, the moment M acts counterclockwise in FIG. 10 with the center of gravity G of both tapered rollers 13 as the origin. Due to this moment M, the rotation axis S of both tapered rollers 13 tilts counterclockwise in FIG. 10 about the center of gravity G. Due to this inclination, each apex side of both tapered rollers 13 approaches races 11 and 12, and the large diameter side of both tapered rollers 13 moves away from races 11 and 12. This makes it easier for the apex sides of both tapered rollers 13 to hit the edges of the races 11 and 12.

Here, regarding the contact surface pressure when the contact states of the tapered rollers 13 with respect to the races 11 and 12 are variously changed, a three-dimensional contact problem analysis program (TED / CP) is used.
Since the calculation is performed using A), it will be described.

The calculation models are Comparative Examples 1 to 3 and Example 1.
It was set to 9 in total. The specifications are shown in Table 1. In addition, in all models, the vertices of both tapered rollers 13 are made flat, and the connecting portion between this flat portion and the conical surface is rounded.

[0041]

[Table 1] In Table 1 above, the conical surface length is the length of the ridgeline from the apex to the large diameter portion in the outer shape in a state where both tapered rollers 13 are not crowned. What is the contact position?
It is the distance from the apex of both tapered rollers 13. The chamfer radius is the radius of curvature of the chamfer provided on the apex side of both tapered rollers 13.

In summary, in Comparative Example 1, as shown in FIG. 11, the outer shape of both tapered rollers 13 is substantially square, and in the unloaded state, both tapered rollers 1 with respect to races 11 and 12 are formed.
The contact position P of No. 3 is arranged on the perpendicular line X passing through the center of gravity G of both tapered rollers 13. In Comparative Example 2, as shown in FIG. 12, the outer shape of both tapered rollers 13 is substantially rhombic, and in the unloaded state, both tapered rollers 1 with respect to races 11 and 12 are formed.
The contact position P of No. 3 is arranged on the perpendicular line X passing through the center of gravity G of both tapered rollers 13. In Comparative Example 3, although not shown, the outer shape of both tapered rollers 13 is substantially rhombic, and both tapered rollers 13 with respect to races 11 and 12 in the unloaded state.
The contact position of X is a vertical line X passing through the center of gravity G of both tapered rollers 13.
It is arranged on the larger diameter side.

Examples 1 to 6 have the same outer shape as that of Comparative Example 3, but in the unloaded state, the contact position of both tapered rollers 13 with respect to races 11 and 12 is larger than that of perpendicular X. It is located on the apex side. Examples 1-6
Changes the radius of curvature of the crowning.

The results obtained when the thrust load was 50 kgf are shown in Table 2 below.

[0045]

[Table 2] In Table 2 above, regarding the moment and the tilt angle, a counterclockwise case is represented by a positive value, and a clockwise case is represented by a negative (-) value.

From the above, the following can be understood.

First, as in Comparative Examples 1 and 2, Race 1
When the contact positions of both tapered rollers 13 with respect to 1 and 12 are arranged on a perpendicular line X passing through the center of gravity G of both tapered rollers 13,
Moment does not work even when thrust load is applied. However, even in this case, the rotation axes S of the tapered rollers 13 are slightly tilted counterclockwise.

However, as in Comparative Example 3, the race 11,
If the contact position of both tapered rollers 13 with respect to 12 is arranged on the larger diameter side than the normal line X passing through the center of gravity G of both tapered rollers 13, the moment acting when the thrust load acts is counterclockwise. In this case, the rotation axis S of both tapered rollers 13
Leans counterclockwise.

On the other hand, as in Examples 1 to 6, Race 1
When the contact positions of both tapered rollers 13 with respect to 1 and 12 are arranged on the apex side of both tapered rollers 13 with respect to the perpendicular line X,
The moment that acts when the thrust load acts is clockwise. In this case, the rotation axis S of both tapered rollers 13 tilts clockwise.

Next, the maximum contact surface pressure is as follows.

Regarding Comparative Examples 1 to 3, Comparative Example 2, Comparative Example 1 and Comparative Example 3 are arranged in the descending order of maximum contact surface pressure. In particular, in Comparative Example 3, the edge load occurred, so that the load was more than twice that in Comparative Example 1. On the other hand, Examples 1 to 5
Is smaller than in Comparative Example 2 above. Example 6
Is smaller than Comparative Examples 1 and 3, but larger than Comparative Example 2.

A comprehensive consideration will be given here. First, based on the results of Comparative Examples 1 and 2, it can be said that it is preferable to make the apex angle of both tapered rollers 13 larger than 90 degrees. In addition, based on the results of Comparative Examples 2 and 3 and Examples 1 to 6, races 11 and 1
The contact position of both tapered rollers 13 with respect to 2 is
Although it may be arranged on the perpendicular line X passing through the center of gravity G of 3, it can be said that it is preferable to arrange it on the apex side of the perpendicular line X.
Further, based on the results of Examples 1 to 6 above, the maximum contact surface pressure decreases as the radius of curvature of the crowning increases, but it can be said that the maximum contact surface pressure increases if it is too large.

As described above, in this embodiment,
By setting the apex angle of both tapered rollers 13 to be larger than 90 degrees, the contact range of both tapered rollers 13 with respect to the races 11 and 12 can be widened, and the contact state of both tapered rollers 13 with respect to the races 11 and 12 can be adjusted. By specifying
It is designed to prevent edge hits.

Therefore, the maximum contact surface pressure can be reduced while preventing the occurrence of edge load on each conical surface of both tapered rollers 13. As a result, the load bearing capacity of each of the tapered rollers 13 increases, which contributes to the improvement of the load bearing capacity and durability of the eccentric thrust bearing 10 and the smooth operation of the orbiting scroll member 3. From this, the eccentric thrust bearing 10
Is also advantageous when used in harsh environments such as poor lubrication conditions.

The present invention is not limited to the above embodiment, and various applications and modifications can be considered.

(1) Both tapered rollers 1 shown in the above embodiment
As for No. 3, as shown in FIG. 13, chamfers 13a and 13b can be applied to the apex and the large diameter portion. If such chamfers 13a and 13b are provided, both tapered rollers 13
It is possible to reliably prevent the apex side and the large diameter side from hitting the edge.

(2) Both tapered rollers 1 shown in the above embodiment
Regarding the outer shape of No. 3, the apex angle .theta. Also in this case, the contact state of both tapered rollers 13 with respect to the races 11 and 12 is set in the same manner as in the above embodiment.

(3) Both tapered rollers 1 shown in the above embodiment
As shown in FIGS. 14 and 15, 3 is a cylindrical shape, and both end surfaces thereof are conical surface shapes are also included in the present invention. Also in these cases, crowning is set in the same manner as in the above-described embodiment.

(4) Both tapered rollers 1 shown in the above embodiment
For the crowning of 3, a logarithmic curve shape can be used.

[0060]

According to the present invention, in addition to the double tapered rollers for the eccentric thrust bearing, the eccentric thrust bearing is provided with the continuous crowning on each conical surface of the double tapered rollers and the contact state between the double tapered rollers and the race is devised. Therefore, when the thrust load is applied, the apex side and the large diameter side of both tapered rollers do not come into edge contact with the race. As a result, the contact surface pressure can be reduced while preventing edge loading on each conical surface of both tapered rollers. Therefore, the rotating and rotating motion of both tapered rollers becomes smooth, which contributes to the smoothness of the operation of the swiveling member and the improvement of the life of the eccentric thrust bearing.

[Brief description of drawings]

FIG. 1 is a sectional view of a scroll compressor using an eccentric thrust bearing according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of an eccentric thrust bearing.

FIG. 3 is a plan view showing the internal structure of an eccentric thrust bearing.

FIG. 4 is a cross-sectional view taken along the line (4)-(4) of FIG.

FIG. 5 is a view showing a state in which the movable side race is eccentric in FIG. 4;

FIG. 6 is a schematic diagram showing the rotational movement of both tapered rollers.

FIG. 7 is a schematic diagram used to explain the operation of an eccentric thrust bearing.

FIG. 8 is an explanatory view showing a contact state of both tapered rollers under no load.

FIG. 9 is an explanatory diagram showing a contact state and a contact range of both tapered rollers when a thrust load is applied.

FIG. 10 is an explanatory view showing various contact states of both tapered rollers.

FIG. 11 is a side view showing both tapered rollers according to Comparative Example 1 of the calculation model.

FIG. 12 is a side view showing both tapered rollers according to Comparative Example 2 of the calculation model.

FIG. 13 is a side view showing another example of the shape of both tapered rollers.

FIG. 14 is a perspective view showing still another example of the shape of both tapered rollers.

FIG. 15 is a side view of the double tapered rollers of FIG.

[Explanation of symbols]

1 scroll compressor 2 rotation axes 3 Orbiting scroll members 4 Fixed scroll member 10 Eccentric thrust bearing 11 Movable race 12 Fixed side race 13 double tapered rollers θ Vertical angle of both tapered rollers S Double tapered roller rotation axis G Center of gravity of both tapered rollers X Vertical line through the center of gravity O Crowning center of curvature P Contact point between both tapered rollers and race

Claims (4)

[Claims] 1. A double tapered roller for an eccentric thrust bearing, which has a shape such that the large diameter portions of two conical bodies are joined together, and has two conical surfaces as rolling surfaces. In the eccentric thrust bearing, continuous crowning is provided, and in the unloaded state, each conical surface is in contact with the race on each apex side of both tapered rollers with respect to the perpendicular line passing through the center of gravity of both tapered rollers. Double tapered rollers. 2. The double tapered roller for eccentric thrust bearing according to claim 1, wherein the apex angle of each of the conical surfaces is set to be larger than 90 degrees. 3. A double tapered roller for an eccentric thrust bearing according to claim 1 or 2, wherein each vertex of the double tapered roller is chamfered. 4. An eccentric thrust bearing which is disposed between a swiveling member which makes an eccentric swivel motion and a fixed member which axially opposes the swiveling member, wherein the thrust bearing is distributed to the facing surfaces of the two members. A race formed by a pair of annular plates provided and a large diameter portion of each of the two cones are joined together, and the two conical surfaces come into contact with each race so as to be rotatable and rotatable. A plurality of both tapered rollers that are rolling surfaces, and continuous crowning is provided on the two conical surfaces of the both tapered rollers, and each conical surface with respect to each race in an unloaded state. Eccentric thrust bearings that are in contact with each other at the apex sides of both tapered rollers with respect to the perpendicular line passing through the center of gravity of both tapered rollers.