JP2002089554A - Multistage thrust bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multistage thrust bearing device having spacers capable of making the amounts of axial deformation uniform while preventing non- uniformity of roller loads. SOLUTION: An outer ring spacer 10, when receiving loads which vary depending on different stages, opens a hole 10a according to the received load to adjust rigidity, although having the same thickness as an inner ring spacer 9, so that by making pairs of rollers 5 and 6, and 7 and 8 equal in length, the loads received by the rollers are made uniform and the amount of axial deformation of the spacer at each stage can be held constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multi-stage thrust bearing capable of receiving a large thrust force.

[0002]

2. Description of the Related Art When a rotating shaft receiving a large force in a thrust direction is supported, a thrust bearing is generally used.
In such a thrust bearing, a roller is sandwiched between a flange-shaped inner ring provided on the rotating shaft side and a flange-shaped outer ring provided on the housing side, and receives a force in a thrust direction.

By the way, as the force in the thrust direction increases, the surface pressure generated between the rollers and the inner and outer rings increases, and there is a problem that the life of the thrust bearing is shortened. In order to reduce the surface pressure generated between the rollers and the inner and outer rings, it is conceivable to reduce the load borne by each roller, but for that purpose, the number of rollers must be increased. However, when the number of rollers is increased, the pitch circle diameter of the rollers is increased, and the diameter of the inner and outer rings is increased. Therefore, there is a problem that the thrust bearing is enlarged in the radial direction.

[0004] In order to solve such a problem, a multi-stage thrust bearing has been developed in which a plurality of stages of inner and outer rings which respectively sandwich rollers are provided in the axial direction. According to such a multi-stage thrust bearing, since the thrust force can be dispersed and received by the rollers sandwiched between the inner and outer rings of each stage, although the outer diameter is small as compared with a normal thrust bearing,
If it is possible to receive a large thrust force, and if it receives the same thrust force, the surface pressure generated between the inner and outer rings will be lower than in the case of ordinary thrust bearings,
Longer life can be expected.

[0005]

However, the conventional multi-stage thrust bearing device has the following problems. Such a problem will be described with reference to the drawings.

FIG. 4 is a sectional view showing a part of a conventional two-stage thrust apparatus. 4, in FIG. 4, between the rotating shaft 11 and the housing 13, the inner ring 1,
2, a multi-stage thrust bearing having outer rows 3, 4 and double-row rollers 5, 6; 7, 8 sandwiched therebetween.

More specifically, the step 11a of the rotating shaft 11
The disk-shaped inner ring 1 is attached to the outer periphery of the rotating shaft 11 such that the inner peripheral side thereof abuts. A thin cylindrical inner ring spacer 9 is provided on the outer periphery of the rotating shaft 11 below the inner ring 1.
Are arranged, and the inner ring 2 is arranged below the.

On the other hand, a disk-shaped outer ring 4 is attached to the cylindrical inner wall 13b of the housing 13 so that the outer peripheral side thereof is in contact with the step 13a of the housing 13. Above the inner ring 4, a thin cylindrical outer ring spacer 10 is arranged on the cylindrical inner wall 13 b, and the inner ring 3 is arranged above the outer ring spacer 10.

Rollers 5 and 6 as rolling elements are sandwiched between the inner ring 1 and the outer ring 3, and between the inner ring 2 and the outer ring 4
Rollers 7, 8 as rolling elements are sandwiched.

Here, the inner ring spacer 9 and the outer ring spacer 10 are
When it receives a thrust force, it is compressed and deformed in the axial direction. The amount of deformation in the axial direction depends on the thrust force applied to the inner ring spacer 9 and the outer ring spacer 10 and the shape of the inner ring spacer 9 and the outer ring spacer 10, but if the respective axial deformation amounts are not equal. In addition, the roller loads at each stage become uneven, resulting in uneven loads such as a very large roller load or only a small roller load, which reduces the life of the entire bearing device. There is a problem that it becomes shorter. Therefore, in general, the thickness of the spacers 9 and 10 is changed to half in FIG. 4 so that the axial rigidity is equal to the thrust force applied to the inner ring spacer 9 and the outer ring spacer 10. In addition, a method of making the amount of deformation in the axial direction equal is employed.

However, the technique of changing the thickness of the spacers 9, 10 requires a thick spacer 9 on the inner ring side as shown in FIG. When the spacer 9 becomes thicker, the roller length becomes shorter and the rated load becomes smaller. Furthermore, 4
As can be seen from FIG. 5 showing a multi-stage thrust bearing having three stages,
As the number of steps increases, the spacers 9 and 9 'have different thicknesses.
9 ": 10, 10 ', 10" is required, and the effect is remarkable.

In view of the above-mentioned problems of the prior art, the present invention provides a multi-stage thrust provided with a spacer capable of making the amount of deformation in the axial direction uniform while preventing uneven roller loads. An object is to provide a bearing device.

[0013]

In order to achieve the above-mentioned object, a multi-stage thrust bearing device according to a first aspect of the present invention is a multi-stage thrust bearing disposed between a shaft and a housing, which is mounted on the shaft. A plurality of inner races, a plurality of outer races attached to the housing, the inner race, and rolling elements each arranged between the outer race adjacent thereto,
One or more inner ring spacers disposed between the plurality of inner rings,
One or more outer ring spacers disposed between the plurality of outer rings,
In at least one of the inner race spacer and the outer race spacer, a spacer receiving a small load has a radial cross-sectional area proportional to the small load with respect to a spacer receiving a large load. Although it has a larger radial cross-sectional area than in the case, it has a structure provided with an adjusting means and a mechanism for adjusting the amount of deformation generated in both spacers so as to approach a side to be equalized.

A multi-stage thrust bearing device according to a second aspect of the present invention comprises:
In a multi-stage thrust bearing disposed between a shaft and a housing, a plurality of inner rings attached to the shaft, a plurality of outer rings attached to the housing, and the inner ring,
Rolling elements respectively disposed between the outer ring adjacent thereto, an inner ring spacer disposed between the plurality of inner rings, and an outer ring spacer disposed between the plurality of outer rings, When the inner ring spacer and the outer ring spacer receive different loads, the spacer receiving a small load,
An adjusting means and a mechanism for adjusting the deformation amount generated in both spacers to be closer to the side where the deformation amount is equalized while having a larger radial cross-sectional area than when having a radial cross-sectional area proportional to the small load. Structure.

[0015]

According to the multi-stage thrust bearing device of the first invention, in a multi-stage thrust bearing disposed between a shaft and a housing, a plurality of inner rings mounted on the shaft and a plurality of outer rings mounted on the housing are provided. Rolling elements disposed between the inner ring and the outer ring adjacent thereto, one or more inner ring spacers disposed between the plurality of inner rings, and disposed between the plurality of outer rings. One or more outer race spacers, and at least one of the inner race spacer and the outer race spacer, a spacer receiving a small load, A structure having an adjusting means and a mechanism for adjusting the deformation amount generated in both spacers to be closer to the side where the deformation amount is equalized, while having a larger radial cross-sectional area than having a radial cross-sectional area proportional to the load. When Therefore, for example, even if the thickness of each inner ring spacer or each outer ring spacer (or each inner ring spacer and each outer ring spacer) is made substantially the same, the amount of axial deformation of each spacer is made constant. By making the length of the rolling element constant regardless of the step, the load applied to the rolling element can be equalized.

According to the multi-stage thrust bearing device of the second aspect of the present invention, in the multi-stage thrust bearing disposed between the shaft and the housing, a plurality of inner rings attached to the shaft;
A plurality of outer rings attached to the housing, the inner ring, and rolling elements respectively arranged between the outer rings adjacent thereto, and an inner ring spacer arranged between the plurality of inner rings,
An outer ring spacer arranged between the plurality of outer rings, and, when the inner ring spacer and the outer ring spacer receive different loads,
Deformation that occurs in both spacers, while a spacer that receives a small load has a larger radial cross-sectional area than a spacer that receives a small load and has a radial cross-sectional area proportional to the small load. Since it has a structure provided with an adjusting means and a mechanism for adjusting so that the amount approaches the equalizing side, for example, even if the inner ring spacer and the outer ring spacer have substantially the same thickness, the axial deformation amount of each spacer is Can be made constant, and the load applied to the rolling element can be equalized by making the length of the rolling element constant regardless of the step.

The structure having the adjusting means and the mechanism is as follows.
It is preferable to include a hole or a recess formed in the peripheral surface of the inner ring spacer or the outer ring spacer. The recessed portion is provided on the peripheral surface of the inner ring spacer so as to partially reduce its thickness.

Here, the ratio of the rigidity in the axial direction when a load is applied to a case where there is a hole in the peripheral surface of the inner ring spacer or the outer ring spacer and a case where there is no hole is c. Thinking relationship. To simplify the description, the shape of the hole is rectangular, the length in the axial direction is a, the length in the circumferential direction is b, and the number of holes is n. Assuming that the displacement in the axial direction when there is no hole is δ1, the following equation is established. δ1 = (L × F) / (π × d × t × E) (1) where L: axial length of the spacer F: axial load applied to the spacer d: center of plate thickness of the spacer The diameter of the position [(inner diameter of spacer + outer diameter of spacer) / 2]. E: Seng rate of spacer material

On the other hand, the displacement in the axial direction when there is a hole is δ2
Then, the following equation is established. δ2 = [(L−a) × F] / (π × d × t × E) + (a × F) / [(π × d−b × n) × t × E] (2) where A = A / L and B = b × n / (π × d), the ratio of the displacement with and without the hole is c = δ1 / δ2 = (1-B) / [(1- A) (1-B) + A] (3) Therefore, if the rigidity of the spacer having holes is K and the rigidity of the spacer having holes is K ′, then K ′ = cK. In the above case, the shape of the hole is rectangular, but in the case of a circular hole, when the radius of the hole is R, A = (2πR ² ) / B
By applying / L, B = 2R × n / (π × d) to the above equation (3), it is possible to approximately determine the stiffness ratio with and without a hole. In order to more accurately obtain the value of c in a hole other than a rectangle or a circle, the finite element method may be used. Further, a load can be applied by an Amsler load tester, and the displacement ratio c at that time can be obtained experimentally. When the value of the displacement ratio c is different between the calculation and the experimental result, it is practical to use the experimental result.

The axial compression stiffness K _il of the n-th inner race _{spacer is} compared to the axial compression stiffness K _il of the first-stage inner race spacer.
_in , and the axial stiffness K of the n-th stage extraneous spacer
It is preferable that the following relationship be established with _{o (Z + 1-n)} . _{0.76 × C n × K il <} K in <1.24 × C n × K il (4) 0.76 × C n × K il <K o (Z + 1-n) <1.24 × C _n × K _il (5) where C _n = (Z + 1−n) / Z, where Z is the number of steps in the spacer.

When the thickness of the outer ring spacer is equal to the thickness of the inner ring spacer, it is preferable to satisfy the expressions (4) and (5). In some cases, when all the spacers have the same thickness, Equation (4),
It is preferable that (5) be satisfied.

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an axial sectional view of a multi-stage thrust bearing according to an embodiment of the present invention. In FIG. 1, between a rotating shaft 11 and a housing 13, a multi-stage thrust having inner races 1, 2, outer races 3, 4, and double-row rollers 5, 6, 7, 8 respectively held therebetween. Bearings are arranged.

More specifically, the step 11a of the rotating shaft 11
The disk-shaped inner ring 1 is attached to the outer periphery of the rotating shaft 11 so that the inner peripheral side of the disk is in contact with the inner peripheral side. A thin cylindrical inner ring spacer 9 is provided on the outer periphery of the rotating shaft 11 below the inner ring 1.
Are arranged, and the inner ring 2 is arranged below it.

On the other hand, a cylindrical outer ring 4 is attached to the cylindrical inner wall 13b of the housing 13 so as to abut on the step 13a of the housing 13 on the outer peripheral side. Above the outer ring 4, a thin cylindrical outer ring spacer 10 is arranged on the cylindrical inner wall 13 b, and the outer ring 3 is arranged above it. Rollers 5 and 6 as rolling elements are held between the inner ring 1 and the outer ring 3, and rollers 7 and 8 as rolling elements are held between the inner ring 2 and the outer ring 4.

In the present embodiment, in order to suppress uneven load, the thickness t _in of the inner race spacer 9 and the outer race spacer 1 are determined.
The thickness t _on with 0 is made equal. The amount of compressive deformation of the inner ring spacer 9 and the outer ring spacer 10 is different only by that, so the rigidity of the outer ring spacer 10 is adjusted to be lower by that amount. As a technique for lowering the rigidity of the outer race spacer 10, there is a method of changing the material, but in the present embodiment,
As shown in FIG. 2, a rectangular hole 10a is formed in the outer race spacer 10 at equal intervals in the circumferential direction as a structure including an adjusting means and a mechanism. Here, there is a problem of how to reduce the rigidity of the outer race spacer 10 to obtain an optimum life.
This will be described below.

The multi-stage thrust bearing device of the present embodiment
It has the following specifications. Inner ring inner diameter: 400 mm Outer ring outer diameter: 800 mm Spacer plate thickness: 12 mm Length of inner ring spacer axis direction: 110 mm Length of outer ring spacer axis direction: 110 mm Number of first stage rollers: 40 Number of second stage rollers: 40 1 Stage roller effective length: 66mm Second stage roller effective length: 66mm Rated load Ca: 10000000N P / Ca: 0.1 Thrust load: 1,000,000N

The axial length L _{i of the} inner race spacer 9 and the outer race spacer 1
0 axial length L _o of the diameter d _i of the thickness of the center position of the ring spacer 9, the diameter d _o of the center position of the thickness of the outer ring spacer 10, the Young's modulus of the inner ring spacer 9 E _i, Young's modulus E _o of the material of the outer ring spacer 10, the thickness t _i of the inner ring spacer 9, the thickness t _o of the outer ring spacer 10, the axial stiffness K _i of the inner ring spacer 9, a hole open the axial stiffness of the outer ring spacer 10 when non K _o, the axial stiffness of the outer ring spacer 10 when the vacant holes and K ₀ ', the following expression holds. K ₀ '= c × K _o (6) _Ki = {(d _i / d _o ) × (E _i / E _o ) × (L _o / L _i )} × K _o (7)

When the ratio Q1 / Q2 of the rolling element load Q1 of the first stage and the rolling element load Q2 of the second stage is obtained using the stiffness ratio c as a parameter, the relationship between c and Q1 / Q2 is as shown in FIG. . c
= 0.5, Q1 = Q2, that is, both rolling element loads become equal. When c is 0.5 or more, the rolling element load of the first stage is large, and when it is 0.5 or less, the rolling element load of the second stage is large.

Further, based on the rolling element loads Q1 and Q2, L
Ungerg-Palmgren's life calculation theory can be applied to calculate the calculated life (for example, "Dynamic Load Capacity of Rolling and Roller Bearings", Junzo Okamoto, Shobunsha, 1990, 2nd printing) . Here, the life L of the rolling bearing
Is represented by the following equation. L = (C / P) ^p (8)

Since a multi-stage thrust bearing has a plurality of rows of rollers, each row has a bearing life characteristic, and the life of the bearing is determined by a combination of the plurality of bearings.

First, for each roller row, the thrust load applied to the bearing is determined by the rolling element load shown in FIG.
The life Li (i: roller train) is obtained from the equation (8).

Further, based on the life Li, the combination life L of a plurality of bearings is obtained by the following formula. 1 / L = (1 / L ₁ ^e + 1 / L ₂ ^e + 1 / L ₃ ^e + 1 / L ₄ ^e ) ^{1 / e} --- (9)

According to the life value obtained by the equation (9), the longest life is obtained when the rolling element load Q1 = Q2. Taking the obtained life value as 1 for the longest life, the rolling element load ratio Q1 /
FIG. 7 is obtained by graphing the relationship between Q2 and the life ratio.
From this figure, in the range of 0.8 ≦ Q1 / Q2 ≦ 1.2, the life value is within approximately 95% of the case where the rolling element load is equal, and by setting the difference of the rolling element load to the above range, Long bearing life is possible.

When the rolling element load ratio is 0.8 ≦ Q1 / Q2 ≦ 1.
In FIG. 6, the rigidity ratio c can be set to 0.38 ≦ c ≦ 0.62 (10) from FIG. Here, in the case of the present embodiment, from the geometrical relationship, d _i / d _o = 0.5, E _i
= E _o , L _o = L _i , and substituting these into the equation (6) gives K _i = 0.5 × K _o (6 ′). Further, both sides are multiplied by 2 to obtain K _o = 2 × K _i (6 ″).

[0035] In this case, a _{K o '= cK o = 2cK} i,
Further, since 0.76 ≦ 2c ≦ 1.24 (10 ′) is obtained based on the equation (10), 0.76 Ki ≦ Ko ′ ≦ 1.24 Ki (11) is obtained from this and the equation (7). Can be

In this embodiment, 0.76 ×
{(D _i / d _o ) × (E _i / E _o ) × (L _o / L _i )} <c <
_{1.24 × {(d i / d} o) × (E i / E o) × (L o /
A hole is made in the outer ring spacer 10 so that L ₁ )｝, and the plate thickness ti of the inner ring spacer 9 is equal to the plate thickness to of the outer ring spacer. Here, the reason why the value of c is given a width is that it is possible to appropriately cope with the situation depending on the situation, such as suppressing the cost of processing a hole, and a case where a large hole cannot be formed due to a problem in strength. .

FIG. 3 is an axial sectional view of a four-stage multi-stage thrust bearing according to another embodiment of the present invention. FIG.
In the figure, only the cross section of the spacer is hatched to make the drawing easier to see. A disk-shaped inner ring 14 is attached to the outer periphery of the rotating shaft 11 so that the inner periphery of the rotating shaft 11 is in contact with the step portion 11a. A thin cylindrical inner ring spacer 2 is provided on the outer periphery of the rotating shaft 11 below the inner ring 14.
6 is disposed, and an inner ring 15 is disposed below the reference numeral 6. On the outer periphery of the rotating shaft 11 below the inner ring 15,
An inner ring spacer 27 having a thin cylindrical shape is arranged, and the inner ring 16 is arranged below the inner ring spacer 27. A thin cylindrical inner race spacer 28 is disposed below the inner race 16 on the outer periphery of the rotating shaft 11, and an inner race 17 is disposed below the inner race spacer 28.

On the other hand, a cylindrical outer ring 21 is attached to the cylindrical inner wall 13b of the housing 13 so as to abut the step 13a of the housing 13 on the outer peripheral side. Above the outer ring 21, a thin cylindrical outer ring spacer 31 is disposed on the cylindrical inner wall 13b, and above the outer ring 20,
Is arranged. Above the outer ring 20, a thin cylindrical outer ring spacer 30 is arranged on the cylindrical inner wall 13b,
The outer ring 19 is disposed above the outer ring 19. Above the outer ring 19, a thin cylindrical outer ring spacer 29 is disposed on the cylindrical inner wall 13b, and the outer ring 18 is disposed above the outer ring spacer 29.

A roller 22 as a rolling element is sandwiched between the inner ring 14 and the outer ring 18, a roller 23 as a rolling element is sandwiched between the inner ring 15 and the outer ring 19, and the inner ring 16 and the outer ring A roller 24 as a rolling element is held between the inner ring 17 and the inner ring 17, and a roller 25 as a rolling element is held between the inner ring 17 and the outer ring 21. The material and the axial length of the outer race spacer and the material and the axial length of the inner race spacer are all the same. In addition, it is assumed that the thicknesses of the inner ring spacers and the outer ring spacers are equal.

When an axial force P acts between the rotating shaft 11 and the housing 13, the load applied to the outer ring spacers 29, 30, 31 is 1/4 × P, 2/4 × P, 3/4 × At P, the ratio is 1: 2: 3. On the other hand, inner ring spacers 26, 27, 2
The load applied to 8 is 3/4 × P, 2/4 × P, 1/4 ×
At P, the ratio becomes 3: 2: 1. Therefore, assuming that the rigidity of the spacer (inner ring spacer 26, outer ring spacer 31) in which no hole is formed is 1, the rigidity ratio c of the center spacer (inner ring spacer 27, outer ring spacer 30) is 0.667. Yes, the opposite side spacer (Inner ring spacer 2
7. The rigidity ratio c of the outer ring spacer 30) is 0.333.

When the above is generalized and applied to the case of a multi-stage thrust bearing device, the above equations (4) and (5)
Is satisfied. _{0.76 × C n × K i1 <} K in <1.24 × C n × K i1 (4) 0.76 × C n × K i1 <K o (Z + 1-n) <1.24 × C _n × K _i1 (5) where K _il is the axial compression stiffness of the first-stage inner ring spacer, and when the number of spacers is Z, Cn = (Z + 1
−n) / Z. Thus, K _in, so K _on is the median value, by'll decide the rigidity of the spacer, can be optimized life multistage thrust bearing device.

Although the present invention has been described with reference to the embodiments, it should be understood that the present invention should not be construed as being limited to the above embodiments, and that modifications and improvements can be made as appropriate. is there. For example, the present invention is not limited to the above-described two-stage thrust bearing device or four-stage thrust bearing device, but is applicable to a three-stage or other-stage thrust bearing device. In addition, various shapes such as a rectangle, a circle, and an ellipse can be used as the shape of the hole, and the hole does not need to penetrate, that is, may be a concave portion.

[0043]

According to the multi-stage thrust bearing device of the first invention, in a multi-stage thrust bearing disposed between a shaft and a housing, a plurality of inner rings mounted on the shaft and a plurality of inner rings mounted on the housing are provided. The outer ring, the inner ring, and rolling elements respectively arranged between the outer ring adjacent thereto, one or more inner ring spacers arranged between the plurality of inner rings, and between the plurality of outer rings. A plurality of outer ring spacers to be arranged, wherein at least one of the inner ring spacer and the outer ring spacer, a spacer receiving a small load, A structure provided with an adjusting means and a mechanism for adjusting the deformation amount generated in both spacers to be closer to a side where the deformation amount is equalized, while having a larger radial cross-sectional area than having a radial cross-sectional area proportional to the load. When Therefore, for example, even if the thickness of each inner ring spacer or each outer ring spacer (or each inner ring spacer and each outer ring spacer) is made substantially the same, the amount of axial deformation of each spacer is made constant. By making the length of the rolling element constant regardless of the step, the load applied to the rolling element can be equalized.

According to the multi-stage thrust bearing device of the second aspect of the present invention, in a multi-stage thrust bearing disposed between a shaft and a housing, a plurality of inner rings attached to the shaft are provided.
A plurality of outer rings attached to the housing, the inner ring, and rolling elements respectively arranged between the outer rings adjacent thereto, and an inner ring spacer arranged between the plurality of inner rings,
An outer ring spacer arranged between the plurality of outer rings, and, when the inner ring spacer and the outer ring spacer receive different loads,
Deformation that occurs in both spacers, while a spacer that receives a small load has a larger radial cross-sectional area than a spacer that receives a small load and has a radial cross-sectional area proportional to the small load. Since it has a structure provided with an adjusting means and a mechanism for adjusting so that it approaches the side of equalizing the amount, for example, even if the thickness of the inner ring spacer and the outer ring spacer is made substantially the same, the axial deformation amount of each spacer Can be made constant, and the load applied to the rolling element can be equalized by making the length of the rolling element constant regardless of the step.

[Brief description of the drawings]

FIG. 1 is an axial sectional view of a two-stage thrust bearing according to a first embodiment.

FIG. 2 is a perspective view (a) and a side view (b) showing an example of an outer ring spacer.

FIG. 3 is an axial sectional view of a four-stage thrust bearing according to a second embodiment.

FIG. 4 is a cross-sectional view showing a part of a two-stage thrust device according to the related art.

FIG. 5 is a cross-sectional view showing a part of a four-stage thrust device according to the related art.

FIG. 6 is a graph showing a relationship between a rigidity ratio and a rolling element load ratio raceway.

FIG. 7 is a graph showing a relationship between a life ratio and a rolling element load ratio.

[Explanation of symbols]

 1,2,14,15,16,17 Inner ring 3,4,18,19,20,21 Outer ring 5,6; 7,8: 22-25 Roller 9,26,27,28 Inner ring spacer 10,29, 30, 31 Outer ring spacer 11 Rotary shaft 13 Housing

Claims (2)

[Claims] 1. A multi-stage thrust bearing disposed between a shaft and a housing, wherein: a plurality of inner rings attached to the shaft; a plurality of outer rings attached to the housing; the inner ring; and the outer ring adjacent thereto. Rolling elements respectively disposed between, and one or more inner ring spacers disposed between the plurality of inner rings, one or more outer ring spacers disposed between the plurality of outer rings,
In at least one of the inner race spacer and the outer race spacer, a spacer receiving a small load has a radial cross-sectional area proportional to the small load with respect to a spacer receiving a large load. A multi-stage thrust bearing device having a structure in which a deformation amount generated in both spacers is made closer to a side for equalizing, while having a larger radial cross-sectional area than in a case. 2. A multi-stage thrust bearing disposed between a shaft and a housing, a plurality of inner rings attached to the shaft, a plurality of outer rings attached to the housing, the inner ring, and the outer ring adjacent thereto. And a rolling element respectively disposed between the plurality of inner rings, an inner ring spacer disposed between the plurality of inner rings, and an outer ring spacer disposed between the plurality of outer rings. When the outer ring spacer receives different loads, the spacer receiving a smaller load has a larger radial cross-sectional area than the spacer receiving a smaller load has a radial cross-sectional area proportional to the smaller load. However, a multi-stage thrust bearing device having a structure in which the amount of deformation generated in both spacers is made closer to the side for equalizing.