JP4051523B2 - Two-stage thrust bearing device and multi-stage thrust bearing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multistage thrust bearing capable of receiving a large thrust force.
[0002]
[Prior art]
When supporting a rotating shaft that receives a large force in the thrust direction, a thrust bearing is generally used. Such a thrust bearing receives a force in the thrust direction by sandwiching a roller between a flange-shaped inner ring provided on the rotating shaft side and a flange-shaped outer ring provided on the housing side.
[0003]
By the way, there is a problem that as the thrust force increases, the surface pressure generated between the rollers and the inner and outer rings increases, and the life of the thrust bearing becomes shorter. 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 in order to do so, 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, which causes a problem that the thrust bearing is enlarged in the radial direction.
[0004]
In response to such a problem, a multi-stage thrust bearing has been developed in which a plurality of stages of inner and outer rings are provided that sandwich the rollers along the axial direction. According to such a multi-stage thrust bearing, the thrust force can be distributed and received by the rollers sandwiched between the inner and outer rings of each stage. Therefore, compared with a normal thrust bearing, although the outer diameter is small, it is large. If the thrust force can be received and if the same thrust force is received, the surface pressure generated between the inner and outer rings is lower than that in the case of a normal thrust bearing, so that a longer life can be expected.
[0005]
[Problems to be solved by the invention]
Incidentally, the conventional multistage thrust bearing device has the following problems. Such a problem will be described with reference to the drawings.
[0006]
FIG. 4 is a cross-sectional view showing a part of a two-stage thrust device in the prior art. 4, in FIG. 4, between the rotating shaft 11 and the housing 13, the inner rings 1 and 2, the outer rings 3 and 4, and the double-row rollers 5, 6; A multi-stage thrust bearing is disposed.
[0007]
More specifically, the disc-shaped inner ring 1 is attached to the outer periphery of the rotating shaft 11 so that the inner peripheral side abuts on the step portion 11 a of the rotating shaft 11. A thin cylindrical inner ring spacer 9 is disposed on the outer periphery of the rotating shaft 11 below the inner ring 1, and the inner ring 2 is disposed below the inner ring spacer 9.
[0008]
On the other hand, a disc-shaped outer ring 4 is attached to the cylindrical inner wall 13 b of the housing 13 so that the outer peripheral side abuts on the step portion 13 a of the housing 13. A thin cylindrical outer ring spacer 10 is disposed on the cylindrical inner wall 13b above the inner ring 4, and the inner ring 3 is disposed above the outer ring spacer 10.
[0009]
Rollers 5 and 6 as rolling elements are sandwiched between the inner ring 1 and the outer ring 3, and rollers 7 and 8 as rolling elements are sandwiched between the inner ring 2 and the outer ring 4.
[0010]
Here, the inner ring spacer 9 and the outer ring spacer 10 are compressed and deformed in the axial direction upon receiving a thrust force. The amount of axial deformation varies depending on the thrust force applied to the inner ring spacer 9 and outer ring spacer 10 and the shape of the inner ring spacer 9 and outer ring spacer 10, but the amount of axial deformation is not equal. , The roller load at each stage becomes uneven, and a very large roller load is applied. On the contrary, only a small roller load is applied. There is a problem of shortening. 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. However, a technique of making the amount of deformation in the axial direction equal is adopted.
[0011]
However, the method of changing the thickness of the spacers 9 and 10 requires a thick spacer 9 on the inner ring side as shown in FIG. When the spacer 9 is thick, the roller length is shortened accordingly, and the rated load is reduced. Further, as is apparent from FIG. 5 showing a four-stage multi-stage thrust bearing, if the number of stages is increased, different thickness spacers 9, 9 ′, 9 ″: 10, 10 ′, 10 ″ are required. The impact is noticeable.
[0012]
Accordingly, in view of the problems of the prior art, the present invention provides a multi-stage thrust bearing device provided with a spacer capable of making the amount of axial deformation uniform while preventing roller load non-uniformity. The purpose is to provide.
[0013]
[Means for Solving the Problems]
  In order to achieve the above-mentioned object, a two-stage thrust bearing device according to a first aspect of the present invention is a two-stage thrust bearing device disposed between a shaft and a housing, and includes two inner rings attached to the shaft, Two outer rings attached to the housing, the inner ring, a rolling element arranged between the adjacent outer rings, an inner ring spacer arranged between the two inner rings, and the gap between the two outer rings And an outer ring spacer disposed on the
  The inner ring spacer and the outer ring spacer are cylindrical, and their thicknesses are equal to each other and are uniform over the axial direction.
  The circumferential surface of the outer ring spacer is spaced apart in the circumferential direction,As adjusting means and mechanism for adjusting the rigidity of the outer ring spacerForming a hole,
  Axial compression stiffness K of inner ring spacer_iAnd of the outer spaceAxial compressionRigidity K_oThe following relationship is established with '.
  0.76 × K_i<K_o‘<1.24 × K_i      (11)
[0014]
  A multi-stage thrust bearing device according to a second aspect of the present invention is a multi-stage thrust bearing device disposed between a shaft and a housing, wherein three or more inner rings attached to the shaft and three or more outer rings attached to the housing. Rolling elements disposed between the inner ring and the outer ring adjacent thereto, a plurality of inner ring spacers disposed between the three or more inner rings, and the three or more outer rings. A plurality of outer ring spacers disposed,
  When the plurality of inner ring spacers receive different loads, the inner ring spacer receiving a large load is larger than the case where the inner ring spacer receiving a small load has a radial cross-sectional area proportional to the small load. While having a cross-sectional area in the radial direction, the deformation amount generated in the inner ring spacer is made closer to the side to be equalized,
  The inner ring spacer is cylindrical, and its thickness is uniform in the axial direction,
  The structure isAs an adjusting means and mechanism for adjusting the rigidity of the inner ring spacer,Formed on the circumferential surface of the inner ring spacer that receives the small load at intervals in the circumferential directionholeAnd formed on the peripheral surface of the inner ring spacer that receives the large load with a circumferential interval.holeAndPreparation,
  Compressive rigidity K in the axial direction of the first stage inner ring spacer_ilIn contrast, the axial compression stiffness K of the n-th inner ring spacer_inAnd the n-th stageAxial compressionRigidity K_{o (Z + 1-n)}The following relationship is established between
  0.76 × Cn × K_il<K_in<1.24 × Cn × K_il  (4)
  0.76 × Cn × K_il<K_{o (Z + 1-n)}<1.24 × Cn × K_il  (5)
Here, Cn = (Z + 1−n) / Z, and Z is the number of steps of the spacer.
  A multi-stage thrust bearing device according to a third aspect of the present invention is a multi-stage thrust bearing device disposed between a shaft and a housing, wherein three or more inner rings attached to the shaft and three or more outer rings attached to the housing. Rolling elements disposed between the inner ring and the outer ring adjacent thereto, a plurality of inner ring spacers disposed between the three or more inner rings, and the three or more outer rings. A plurality of outer ring spacers disposed,
  When the plurality of outer ring spacers receive different loads, the outer ring spacer receiving a large load is larger than the case where the outer ring spacer receiving a small load has a radial cross-sectional area proportional to the small load. While having a cross-sectional area in the radial direction, a structure that brings the deformation amount generated in the outer ring spacer closer to the side to be equalized,
  The outer ring spacer is cylindrical, and its thickness is uniform in the axial direction,
  The structure isAs an adjusting means and mechanism for adjusting the rigidity of the outer ring spacer,Formed on the circumferential surface of the outer ring spacer that receives the small load at intervals in the circumferential direction.holeAnd formed on the peripheral surface of the outer ring spacer that receives the large load at intervals in the circumferential direction.holeAndPreparation,
  Compressive rigidity K in the axial direction of the first stage inner ring spacer_ilIn contrast, the axial compression stiffness K of the n-th inner ring spacer_inAnd the n-th stageAxial compressionRigidity K_{o (Z + 1-n)}The following relationship is established between
  0.76 × Cn × K_il<K_in<1.24 × Cn × K_il  (4)
  0.76 × Cn × K_il<K_{o (Z + 1-n)}<1.24 × Cn × K_il  (5)
Here, Cn = (Z + 1−n) / Z, and Z is the number of steps of the spacer.
[0015]
[Action]
  According to the two-stage thrust bearing device of the first aspect of the present invention, in the two-stage thrust bearing device arranged between the shaft and the housing, the two inner rings attached to the shaft and the two outer rings attached to the housing Rolling elements disposed between the inner ring and the outer ring adjacent thereto, an inner ring spacer disposed between the two inner rings, and an outer ring spacer disposed between the two outer rings. The inner ring spacer and the outer ring spacer are cylindrical, and the wall thickness thereof is equal to each other and uniform over the axial direction, and the circumferential surface of the outer ring spacer is arranged in the circumferential direction. With an intervalAs adjusting means and mechanism for adjusting the rigidity of the outer ring spacerCompressive rigidity K in the axial direction of the inner ring spacer_iAnd of the outer spaceAxial compressionRigidity K_oSince the expression (11) is established between the inner ring spacer and the outer ring spacer, for example, the axial deformation amount of each spacer is made constant even if the thicknesses of the inner ring spacer and the outer ring spacer are substantially the same. And by making the length of the rolling element constant regardless of the stage, the load received by it can be equalized.
[0016]
  According to the multistage thrust bearing device of the second aspect of the present invention, in the multistage thrust bearing device arranged between the shaft and the housing, three or more inner rings attached to the shaft and three or more attached to the housing. Rolling rings disposed between the outer ring, the inner ring, and the outer ring adjacent thereto, a plurality of inner ring spacers disposed between the three or more inner rings, and the three or more outer rings. An inner ring spacer that receives a small load with respect to the inner ring spacer that receives a large load when the plurality of inner ring spacers receive different loads. While having a larger radial cross-sectional area than the case of having a radial cross-sectional area proportional to the small load, it is configured to approach the side to equalize the amount of deformation generated in the inner ring spacer, the structure,As an adjusting means and mechanism for adjusting the rigidity of the inner ring spacer,Formed on the circumferential surface of the inner ring spacer that receives the small load at intervals in the circumferential directionholeAnd formed on the peripheral surface of the inner ring spacer that receives the large load with a circumferential interval.holeAndPreparationCompressive stiffness K in the axial direction of the first stage inner ring spacer_ilIn contrast, the axial compression stiffness K of the n-th inner ring spacer_inAnd the n-th stageAxial compressionRigidity K_{o (Z + 1-n)}Since the equations (4) and (5) are established between the inner ring spacer and the inner ring spacer, for example, the axial deformation amount of each inner ring spacer can be constant. It is possible to equalize the load received by making the length of the rolling element constant regardless of the stage.
  According to the multistage thrust bearing device of the third aspect of the present invention, in the multistage thrust bearing device disposed between the shaft and the housing, three or more inner rings attached to the shaft and three or more attached to the housing. Rolling rings disposed between the outer ring, the inner ring, and the outer ring adjacent thereto, a plurality of inner ring spacers disposed between the three or more inner rings, and the three or more outer rings. A plurality of outer ring spacers disposed between, and when the plurality of outer ring spacers receive different loads, an outer ring spacer that receives a small load with respect to the outer ring spacer that receives a large load, While having a larger radial cross-sectional area than the case of having a radial cross-sectional area proportional to the small load, the outer ring spacer is configured to approach the side to equalize the amount of deformation generated in the outer ring spacer, Cylindrical Te, and the thickness thereof is uniform in the axial direction, the structure,As an adjusting means and mechanism for adjusting the rigidity of the outer ring spacer,Formed on the circumferential surface of the outer ring spacer that receives the small load at intervals in the circumferential direction.holeAnd formed on the peripheral surface of the outer ring spacer that receives the large load at intervals in the circumferential direction.holeAndPreparationCompressive stiffness K in the axial direction of the first stage inner ring spacer_ilIn contrast, the axial compression stiffness K of the n-th inner ring spacer_inAnd the n-th stageAxial compressionRigidity K_{o (Z + 1-n)}Since the equations (4) and (5) are established between the inner ring spacer and the outer ring spacer, for example, the axial deformation amount of each inner ring spacer can be constant. It is possible to equalize the load received by making the length of the rolling element constant regardless of the stage.
[0017]
  The structure including the adjusting means and the mechanism is formed on a peripheral surface of the inner ring spacer or the outer ring spacer.Including holes.
[0018]
Here, the ratio of axial rigidity when a load is applied to the case where there is a hole on the peripheral surface of the inner ring spacer or the outer ring spacer and when there is no hole is c, and the relationship between the shape of the hole and c is considered. . In order to simplify the description, the hole shape is rectangular, the axial length is a, the circumferential length is b, and the number of holes is n. When the axial displacement when there is no hole is δ1, the following equation is established.
δ1 = (L × F) / (π × d × t × E) (1)
However,
L: Axial length of spacer
F: Axial load received by the spacer
d: Diameter of the center position of the thickness of the spacer [(inner diameter of spacer + outer diameter of spacer) / 2].
E: Seng rate of spacer material
[0019]
On the other hand, when the axial displacement when there is a hole is δ2, the following equation is established.
δ2 = [(L−a) × F] / (π × d × t × E)
+ (A × F) / [(π × db−n) × t × E] (2)
Here, if A = a / L and B = b × n / (π × d), the displacement ratio between the case with and without the hole is
c = δ1 / δ2 = (1-B) / [(1-A) (1-B) + A] (3)
It becomes. Therefore, if the stiffness of the spacer without holes is K and the stiffness of the spacer with holes is K ',
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 = (2πR²) / B / L, B = 2R × n / (π × d) is applied to the above equation (3), whereby the rigidity ratio in the case of no hole is approximately obtained. In the case of obtaining the value of c more accurately in a hole other than a rectangle or a circle, the finite element method may be used. Furthermore, a load is applied by an Amsler load tester, and the displacement ratio c at that time can also be obtained experimentally. When the value of the displacement ratio c differs between the calculation and the experimental result, it is practical to use the experimental result.
[0020]
  Also, the axial compression stiffness K of the first stage inner ring spacer_ilIn contrast, the axial compression stiffness K of the n-th inner ring spacer_inAnd the n-th stageAxial compressionRigidity K_{o (Z + 1-n)}The following relationship is preferably established between
  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 of the spacer.
[0021]
In addition, 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). It is preferable to satisfy the expressions (4) and (5) when the thicknesses of all the spacers are equal.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an axial sectional view of a multistage thrust bearing according to an embodiment of the present invention. In FIG. 1, a multi-stage thrust having inner rings 1, 2, outer rings 3, 4 and double row rollers 5, 6, 7, 8 held between the rotating shaft 11 and the housing 13. A bearing is arranged.
[0023]
More specifically, the disc-shaped inner ring 1 is attached to the outer periphery of the rotating shaft 11 so that the inner peripheral side abuts on the step portion 11 a of the rotating shaft 11. A thin cylindrical inner ring spacer 9 is disposed on the outer periphery of the rotating shaft 11 below the inner ring 1, and the inner ring 2 is disposed below the inner ring spacer 9.
[0024]
On the other hand, a cylindrical outer ring 4 is attached to a cylindrical inner wall 13 b of the housing 13 so as to abut on the outer peripheral side of the step portion 13 a of the housing 13. A thin cylindrical outer ring spacer 10 is disposed on the cylindrical inner wall 13b above the outer ring 4, and the outer ring 3 is disposed 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 rollers 7 and 8 as rolling elements are sandwiched between the inner ring 2 and the outer ring 4.
[0025]
In the present embodiment, the thickness t of the inner ring spacer 9 is used to suppress uneven load._inAnd outer ring spacer 10 thickness t_onAre equal. Only by that, the amount of compressive deformation of the inner ring spacer 9 and the outer ring spacer 10 is different, and accordingly, the rigidity of the outer ring spacer 10 is adjusted to be lowered accordingly. As a method for reducing the rigidity of the outer ring spacer 10, the material may be changed. However, in the present embodiment, as shown in FIG. 2, the outer ring spacer 10 has a structure including an adjusting unit and a mechanism. The rectangular holes 10a are spaced at equal intervals in the circumferential direction. Here, there is a problem that an optimum life can be obtained if the rigidity of the outer ring spacer 10 is lowered. This will be described below.
[0026]
The multistage thrust bearing device of the present embodiment has the following specifications.
Inner ring inner diameter: 400mm
Outer ring outer diameter: 800mm
Spacer plate thickness: 12 mm
Inner ring spacer axial length: 110 mm
Outer ring spacer axial length: 110mm
Number of first stage rollers: 40
Number of rollers on the second stage: 40
First stage roller effective length: 66mm
Second stage roller effective length: 66mm
Rated load Ca: 10000000N
P / Ca: 0.1
Thrust load: 1000000N
[0027]
  Axial length L of inner ring spacer 9_i, Axial length L of outer ring spacer 10_o, Diameter d of the center position of the thickness of the inner ring spacer 9_i, Diameter d of the center position of the thickness of the outer ring spacer 10_o, The Young's modulus of the material of the inner ring spacer 9 is E_i, The Young's modulus of the material of the outer ring spacer 10 is E_o, Thickness t of inner ring spacer 9_i, Thickness t of outer ring spacer 10_o, Axial rigidity K of inner ring spacer 9_i, The axial rigidity of the outer ring spacer 10 when there is no hole._o, Of outer ring spacer 10 when there is a holeAxial compressionStiffness is K₀If ′, the following equation is established.
  K₀′ = C × K_o   (6)
  K_i= {(D_i/ D_o) × (E_i/ E_o) X (L_o/ L_i)} × K_o   (7)
It can be expressed as
[0028]
When the ratio Q1 / Q2 between the first-stage rolling element load Q1 and the second-stage rolling element load Q2 is obtained using the rigidity ratio c as a parameter, the relationship between c and Q1 / Q2 is as shown in FIG. When c = 0.5, Q1 = Q2, that is, both rolling element loads are equal. When c is 0.5 or more, the first-stage rolling element load is large. Conversely, when c is 0.5 or less, the second-stage rolling element load is large.
[0029]
Furthermore, based on the rolling element loads Q1 and Q2, the calculation life can be obtained by applying the Lundgerg-Palmgren life calculation theory (for example, “Dynamic load capacity of rolling bearings / roller bearings” Junzo Okamoto Written by Shobunsha, 1990, second print). Here, the life L of the rolling bearing is expressed by the following equation.
L = (C / P)^p                              (8)
[0030]
Since a multi-stage thrust bearing has a plurality of rows of rollers, each row has its own bearing life characteristics, and the bearing life is determined by a combination of the plurality of bearings.
[0031]
First, for each roller train, the thrust load applied to the bearing is determined by the rolling element load of FIG. 5, and the life Li (i: roller train) is obtained from equation (8).
[0032]
Further, based on the above life Li, the combined life L of a plurality of bearings can be obtained using the following calculation formula.
1 / L = (1 / L₁ ^e+ 1 / L₂ ^e+ 1 / L_Three ^e+ 1 / L_Four ^e)^{1 / e}--- (9)
[0033]
According to the life value obtained by the equation (9), the longest life is obtained when the rolling element load Q1 = Q2. FIG. 7 is obtained by graphing the relationship between the rolling element load ratio Q1 / Q2 and the life ratio, assuming that the obtained life value is 1 for the longest life. From this figure, the life value in the range of 0.8 ≦ Q1 / Q2 ≦ 1.2 is within approximately 95% of the case where the rolling element load is equal. By making the difference of the rolling element load into the above range, Longer bearing life is possible.
[0034]
To set the rolling element load ratio to 0.8 ≦ Q1 / Q2 ≦ 1.2, the rigidity ratio c is determined from FIG.
0.38 ≦ c ≦ 0.62 (10)
It becomes possible by setting. Here, in the case of this embodiment, from the geometric relationship, d_i/ D_o= 0.5, E_i= E_o, L_o= L_iTherefore, if this is substituted into equation (6),
K_i= 0.5 × K_o                                            (6 ’)
Is obtained. Furthermore, multiply both sides by 2,
K_o= 2 × K_i                                                (6 ”)
Get.
[0035]
Where K_o′ = CK_o= 2cK_iFurthermore, based on equation (10),
0.76 ≦ 2c ≦ 1.24 (10 ′)
From this and equation (7),
0.76 Ki ≦ Ko ′ ≦ 1.24 Ki (11)
Is obtained.
[0036]
In the present embodiment, 0.76 × {(d_i/ D_o) × (E_i/ E_o) X (L_o/ L_i)} <C <1.24 × {(d_i/ D_o) × (E_i/ E_o) X (L_o/ L₁)}, A hole is made in the outer ring spacer 10 so that 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, for example, by suppressing the cost when processing the hole, or when a large hole cannot be formed due to strength problems. .
[0037]
FIG. 3 is an axial sectional view of a four-stage multi-stage thrust bearing according to another embodiment of the present invention. In FIG. 3, only the cross section of the spacer is hatched to make the drawing easy to see. A disc-shaped inner ring 14 is attached to the outer periphery of the rotating shaft 11 so that the inner peripheral side abuts on the step portion 11 a of the rotating shaft 11. A thin cylindrical inner ring spacer 26 is disposed on the outer periphery of the rotating shaft 11 below the inner ring 14, and an inner ring 15 is disposed below the inner ring spacer 26. A thin cylindrical inner ring spacer 27 is disposed on the outer periphery of the rotary shaft 11 below the inner ring 15, and an inner ring 16 is disposed below the inner ring spacer 27. A thin cylindrical inner ring spacer 28 is disposed on the outer periphery of the rotary shaft 11 below the inner ring 16, and an inner ring 17 is disposed below the inner ring spacer 28.
[0038]
On the other hand, a cylindrical outer ring 21 is attached to the cylindrical inner wall 13 b of the housing 13 so as to abut on the outer peripheral side of the step portion 13 a of the housing 13. A thin cylindrical outer ring spacer 31 is disposed on the cylindrical inner wall 13b above the outer ring 21, and the outer ring 20 is disposed above the outer ring spacer 31. A thin cylindrical outer ring spacer 30 is arranged on the cylindrical inner wall 13b above the outer ring 20, and an outer ring 19 is arranged above it. A thin cylindrical outer ring spacer 29 is disposed on the cylindrical inner wall 13b above the outer ring 19, and an outer ring 18 is disposed above the outer ring spacer 29.
[0039]
A roller 22 as a rolling element is sandwiched between the inner ring 14 and the outer ring 18, and a roller 23 as a rolling element is sandwiched between the inner ring 15 and the outer ring 19. A roller 24 as a rolling element is sandwiched between them, and a roller 25 as a rolling element is sandwiched between the inner ring 17 and the outer ring 21. The material and axial length of the outer ring spacer, the material and axial length of the inner ring spacer are all assumed to be equal. The inner ring spacers and the outer ring spacers are equal in thickness.
[0040]
When an axial force of P is applied between the rotary 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 × P, The ratio is 1: 2: 3. On the other hand, the load applied to the inner ring spacers 26, 27, and 28 is 3/4 × P, 2/4 × P, and 1/4 × P, and the ratio is 3: 2: 1. Therefore, if the rigidity of the spacer (inner ring spacer 26, outer ring spacer 31) where the hole is not drilled is 1, the rigidity ratio c of the center spacer (inner ring spacer 27, outer ring spacer 30) is 0.667. Yes, the stiffness ratio c of the opposite spacer (inner ring spacer 27, outer ring spacer 30) is 0.333.
[0041]
When the above is generalized and applied to a multi-stage thrust bearing device,
The conditions of the above formulas (4) and (5) are established.
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)
However, K_ilIs the compression rigidity in the axial direction of the first inner ring spacer, where Cn = (Z + 1−n) / Z, where Z is the number of steps of the spacer. Like this, K_in, K_onBy determining the rigidity of the spacer so that becomes the median, the life of the multistage thrust bearing device can be optimized.
[0042]
  The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be modified or improved as appropriate. For example, the present invention is not limited to the above-described two-stage thrust bearing device or four-stage thrust bearing device, and can be applied 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 for the hole, and the hole penetrates.Say things.
[0043]
【The invention's effect】
  According to the two-stage thrust bearing device of the first aspect of the present invention, in the two-stage thrust bearing device arranged between the shaft and the housing, the two inner rings attached to the shaft and the two outer rings attached to the housing Rolling elements disposed between the inner ring and the outer ring adjacent thereto, an inner ring spacer disposed between the two inner rings, and an outer ring spacer disposed between the two outer rings. The inner ring spacer and the outer ring spacer are cylindrical, and the wall thickness thereof is equal to each other and uniform over the axial direction, and the circumferential surface of the outer ring spacer is arranged in the circumferential direction. Compressive stiffness K in the axial direction of the inner ring spacer by forming holes at intervals_iAnd of the outer spaceAxial compressionRigidity K_oSince the expression (11) is established between the inner ring spacer and the outer ring spacer, for example, the axial deformation amount of each spacer is made constant even if the thicknesses of the inner ring spacer and the outer ring spacer are substantially the same. And by making the length of the rolling element constant regardless of the stage, the load received by it can be equalized.
[0044]
  According to the multistage thrust bearing device of the second aspect of the present invention, in the multistage thrust bearing device arranged between the shaft and the housing, three or more inner rings attached to the shaft and three or more attached to the housing. Rolling rings disposed between the outer ring, the inner ring, and the outer ring adjacent thereto, a plurality of inner ring spacers disposed between the three or more inner rings, and the three or more outer rings. An inner ring spacer that receives a small load with respect to the inner ring spacer that receives a large load when the plurality of inner ring spacers receive different loads. While having a larger radial cross-sectional area than the case where it has a radial cross-sectional area proportional to the small load, the inner ring spacer is configured to approach the side to equalize the amount of deformation generated in the inner ring spacer, Cylindrical Te, and the thickness thereof is uniform in the axial direction, the structure,As an adjusting means and mechanism for adjusting the rigidity of the inner ring spacer,Formed on the circumferential surface of the inner ring spacer that receives the small load at intervals in the circumferential directionholeAnd formed on the peripheral surface of the inner ring spacer that receives the large load with a circumferential interval.holeAndPreparationCompressive stiffness K in the axial direction of the first stage inner ring spacer_ilIn contrast, the axial compression stiffness K of the n-th inner ring spacer_inAnd the n-th stageAxial compressionRigidity K_{o (Z + 1-n)}Since the equations (4) and (5) are established between the inner ring spacer and the inner ring spacer, for example, the axial deformation amount of each inner ring spacer can be constant. It is possible to equalize the load received by making the length of the rolling element constant regardless of the stage.
  According to the multistage thrust bearing device of the third aspect of the present invention, in the multistage thrust bearing device disposed between the shaft and the housing, three or more inner rings attached to the shaft and three or more attached to the housing. Rolling rings disposed between the outer ring, the inner ring, and the outer ring adjacent thereto, a plurality of inner ring spacers disposed between the three or more inner rings, and the three or more outer rings. A plurality of outer ring spacers disposed between, and when the plurality of outer ring spacers receive different loads, an outer ring spacer that receives a small load with respect to the outer ring spacer that receives a large load, While having a larger radial cross-sectional area than the case of having a radial cross-sectional area proportional to the small load, the outer ring spacer is configured to approach the side to equalize the amount of deformation generated in the outer ring spacer, Cylindrical Te, and the thickness thereof is uniform in the axial direction, the structure,As an adjusting means and mechanism for adjusting the rigidity of the outer ring spacer,Formed on the circumferential surface of the outer ring spacer that receives the small load at intervals in the circumferential direction.holeAnd formed on the peripheral surface of the outer ring spacer that receives the large load at intervals in the circumferential direction.holeAndPreparationCompressive stiffness K in the axial direction of the first stage inner ring spacer_ilIn contrast, the axial compression stiffness K of the n-th inner ring spacer_inAnd the n-th stageAxial compressionRigidity K_{o (Z + 1-n)}Since the equations (4) and (5) are established between the inner ring spacer and the outer ring spacer, for example, the axial deformation amount of each inner ring spacer can be constant. It is possible to equalize the load received by making the length of the rolling element constant regardless of the stage.
[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 sectional view showing a part of a two-stage thrust device in the prior art.
FIG. 5 is a sectional view showing a part of a four-stage thrust device in the prior art.
FIG. 6 is a graph showing the relationship between the rigidity ratio and the rolling element load ratio race.
FIG. 7 is a graph showing the relationship between the life ratio and the 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
9, 26, 27, 28 Inner ring spacer
10, 29, 30, 31 Outer ring spacer
11 Rotating shaft
13 Housing

Claims (4)

In the two-stage thrust bearing device disposed between the shaft and the housing, between the two inner rings attached to the shaft, the two outer rings attached to the housing, the inner ring, and the outer ring adjacent thereto. Each of the rolling elements, an inner ring spacer disposed between the two inner rings, and an outer ring spacer disposed between the two outer rings,
The inner ring spacer and the outer ring spacer are cylindrical, and their thicknesses are equal to each other and are uniform over the axial direction.
On the peripheral surface of the outer ring spacer, a hole is formed as an adjusting means and mechanism for adjusting the rigidity of the outer ring spacer with a space in the circumferential direction.
A two-stage thrust bearing device in which the following relationship is established between the axial compression stiffness K _{i of the} inner ring spacer and the axial compression stiffness K _o ′ of the outer space spacer.
0.76 × K _i <K _o ′ <1.24 × K _i (11) In a multistage thrust bearing device disposed between a shaft and a housing, three or more inner rings attached to the shaft, three or more outer rings attached to the housing, the inner ring, and the outer ring adjacent thereto Rolling elements respectively disposed between the three or more inner rings, a plurality of inner ring spacers disposed between the three or more inner rings, and a plurality of outer ring spacers disposed between the three or more outer rings. And
When the plurality of inner ring spacers receive different loads, the inner ring spacer receiving a large load is larger than the case where the inner ring spacer receiving a small load has a radial cross-sectional area proportional to the small load. While having a cross-sectional area in the radial direction, the deformation amount generated in the inner ring spacer is made closer to the side to be equalized,
The inner ring spacer is cylindrical, and its thickness is uniform in the axial direction,
In the structure, as an adjusting means and mechanism for adjusting the rigidity of the inner ring spacer, a hole formed in the circumferential surface of the inner ring spacer that receives the small load at a circumferential interval and the large load is received. Provided with a hole formed in the circumferential surface of the inner ring spacer at intervals in the circumferential direction,
With respect to the axial direction of the compressive stiffness K _il of the inner ring spacer in the first stage, between the compressive stiffness K _in the axial direction of the inner ring spacer of the n-th stage, and the axial direction of the outer輸間seat of the n-th stage Multi-stage thrust bearing device in which the following relationship is established with the compression stiffness K _{o (Z + 1-n) of}
0.76 × Cn × K _il <K _in <1.24 × Cn × K _il (4)
0.76 * Cn * _Kil < _{Ko (Z + 1-n)} <1.24 * Cn * _Kil (5)
Here, Cn = (Z + 1−n) / Z, and Z is the number of steps of the spacer. In a multistage thrust bearing device disposed between a shaft and a housing, three or more inner rings attached to the shaft, three or more outer rings attached to the housing, the inner ring, and the outer ring adjacent thereto Rolling elements respectively disposed between the three or more inner rings, a plurality of inner ring spacers disposed between the three or more inner rings, and a plurality of outer ring spacers disposed between the three or more outer rings. And
When the plurality of outer ring spacers receive different loads, the outer ring spacer receiving a large load is larger than the case where the outer ring spacer receiving a small load has a radial cross-sectional area proportional to the small load. While having a cross-sectional area in the radial direction, a structure that brings the deformation amount generated in the outer ring spacer closer to the side to be equalized,
The outer ring spacer is cylindrical, and its thickness is uniform in the axial direction,
In the structure, as an adjusting means and mechanism for adjusting the rigidity of the outer ring spacer, a hole formed in the circumferential surface of the outer ring spacer that receives the small load at a circumferential interval and the large load. Provided with a hole formed in the circumferential surface of the outer ring spacer at intervals in the circumferential direction,
With respect to the axial direction of the compressive stiffness K _il of the inner ring spacer in the first stage, between the compressive stiffness K _in the axial direction of the inner ring spacer of the n-th stage, and the axial direction of the outer輸間seat of the n-th stage Multi-stage thrust bearing device in which the following relationship is established with the compression stiffness K _{o (Z + 1-n) of}
0.76 × Cn × K _il <K _in <1.24 × Cn × K _il (4)
0.76 * Cn * _Kil < _{Ko (Z + 1-n)} <1.24 * Cn * _Kil (5)
Here, Cn = (Z + 1−n) / Z, and Z is the number of steps of the spacer.   The multi-stage thrust bearing device according to any one of claims 1 to 3, wherein the hole has an axial dimension larger than an axial thickness of the outer ring and the inner ring.

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