JP2004084819A - Cage for bearing, and bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cage for bearing which restricts a revolution component of a rolling body among NRRO, while securing a flow of the lubricant between a pocket surface and the rolling body. <P>SOLUTION: A pocket 20 of the cage 10 is formed of an inside pocket surface 22, an intermediate pocket surface 28 and an outside pocket surface 34. The inside pocket surface 22 and the outside pocket surface 34 are respectively formed of two spherical pocket surfaces, of which center of curvature is displaced from each other, and the intermediate pocket surface 28 is formed of two cylindrical pocket surfaces, of which center axis are displaced from each other. A ratio of the minimum value δ<SB>Hmin</SB>of a clearance δ<SB>H</SB>in the circumferential direction formed between the inside pocket surface 22 and the outside pocket surface 34 and a rotating surface of the rolling body in the non-load condition to a rotation diameter D<SB>B</SB>of the rolling body is set in a range at 0.01-0.02 to structure the cage 10 for bearing. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a bearing retainer such as a deep groove ball bearing used for a motor or the like that requires low vibration, and a bearing having the bearing retainer.
[0002]
[Prior art]
2. Description of the Related Art Rolling bearings for driving motors such as hard disk drives mounted on personal computers and the like are required to reduce rotation asynchronous vibration (NRRO) that is not synchronized with rotation of the motor.
In a conventional cage used for a rolling bearing for achieving a low NRRO, a pocket surface of a pocket that houses and holds a rolling element is formed by a single spherical surface. Then, the clearance between the rolling element and the pocket surface is reduced, the amount of movement of the rolling element in the circumferential direction is reduced, and the rolling element revolution component of NRRO is suppressed.
[0003]
[Problems to be solved by the invention]
However, even if an attempt is made to achieve a low NRRO by reducing the gap between the rolling element and the pocket surface, there has been a problem that the flow of the lubricant between the rolling element and the pocket surface is hindered. And, the hindrance of the flow of the lubricant reduces the acoustic life and increases the dynamic friction torque. For this reason, there is a certain limit in achieving a low NRRO by reducing the gap between the rolling element and the pocket surface.
[0004]
The present invention has been made in order to eliminate the above-mentioned problems of the conventional technology, and an object of the present invention is to secure the flow of a lubricant between a rolling element and a pocket surface that accommodates and holds a rolling element. Another object of the present invention is to provide a bearing retainer and a bearing capable of suppressing a revolving component of a rolling element in NRRO.
[0005]
[Means for Solving the Problems]
The present invention has the following configuration to solve the problem. The invention according to claim 1 is characterized in that the pockets for accommodating and holding the rolling elements are formed at a plurality of positions in the circumferential direction by the inner wall of the pocket, which is entirely annular, and the pocket is formed on one side in the axial direction of each pocket. In a bearing retainer provided with an opening having an opening width smaller than a diameter of a rolling element, at least one of the plurality of pockets has a pocket inner wall in which an inner pocket surface and an outer pocket surface are formed in a radial direction. A second spherical pocket formed side by side and connecting the inner pocket surface to a first spherical pocket surface on the side of the opening and a first spherical pocket surface on the side opposite to the opening. And the center of the radius of curvature of the first spherical pocket surface and the center of the radius of curvature of the second spherical pocket surface are offset from each other. The third spherical pocket surface is formed by a third spherical pocket surface on the opening side and a fourth spherical pocket surface connected to the third spherical pocket surface on the side opposite to the opening. This is a bearing retainer in which the center of the radius of curvature of the surface and the center of the radius of curvature of the fourth spherical pocket surface are shifted from each other.
[0006]
According to the first aspect of the present invention, the inner wall of the pocket is formed by combining four spherical pocket surfaces each having a concave surface of a part of the spherical surface. The centers of the radii of curvature of the spherical surfaces forming the first spherical pocket surface and the second spherical pocket surface are deviated from each other and eccentric, and a boundary portion between the first spherical pocket surface and the second spherical pocket surface. Form a valley. The rolling element cannot penetrate deep into the boundary, and there is always a gap between the rolling element and this boundary, and the lubricant can flow through this gap. The same applies to the boundary between the third spherical pocket surface and the fourth spherical pocket surface, and there is always a gap between the rolling element and the lubricant.
[0007]
Excess lubricant adhering to the surface of the rolling element is scraped off at the ends of the first spherical pocket surface and the second spherical pocket surface, thereby preventing the dynamic friction torque from becoming excessive. Similarly, at the ends of the third spherical pocket surface and the fourth spherical pocket surface, excess lubricant adhering to the surface of the rolling element is scraped off.
Therefore, the distance between the rolling element and the inner wall of the pocket is reduced to suppress the revolving component of the rolling element in the NRRO, and at the same time, the flow of the lubricant is secured between the inner wall of the pocket and the rolling element, and the acoustic life is shortened. Is prevented, and the dynamic friction torque can be kept low.
[0008]
The direction of the center axis of the bearing cage is referred to as an axial direction. The direction perpendicular to the center axis of the bearing retainer and radially away from the center axis is referred to as a radial direction. Further, a direction along the circumference of the bearing retainer is referred to as a circumferential direction.
The invention according to claim 2 is the bearing retainer according to claim 1, wherein the circle formed between the rotating surface of the rolling element and the first spherical pocket surface in a no-load state. Circumferential distance δ_HIMinimum value of δ_HIminAnd the rotation diameter D of the rolling element_BRatio δ_HImin/ D_BIs set to 0.01 to 0.02, and the circumferential distance δ between the rotating surface of the rolling element and the third spherical pocket surface in a no-load state is set._HOMinimum value of δ_HOminAnd the rotation diameter D of the rolling element_BRatio δ_HOmin/ D_BIs a bearing retainer in which the value range is set to 0.01 to 0.02.
[0009]
When the rolling element moves in the circumferential direction while rotating in the pocket, and the rolling element contacts the first spherical pocket surface and the second spherical pocket surface, the distance that the rolling element moves in the circumferential direction is δ._HIMinimum value of δ_HIminΔ_HIIs the maximum value δ at the boundary between the first spherical pocket surface and the second spherical pocket surface._HImaxTake. Therefore, at least δ is provided between the boundary and the rolling element._HIMaximum value of δ_HImaxAnd the minimum value δ_HIminAnd a gap always exists, and the lubricant flows through this gap. Similarly, at least δ is provided between the rolling element and the boundary between the third spherical pocket surface and the fourth spherical pocket surface._HOMaximum value of δ_HOmaxAnd the minimum value δ_HOminAnd a gap always exists, and the lubricant flows through this gap. Therefore, the distance between the rolling element and the inner wall of the pocket is reduced to suppress the revolving component of the rolling element in the NRRO, and at the same time, the flow of the lubricant is secured between the inner wall of the pocket and the rolling element, and the acoustic life is shortened. Is prevented, and the dynamic friction torque can be kept low.
[0010]
Also, δ_HOmin/ D_BThe value of or δ_HImin/ D_BIs less than 0.01, the dynamic friction torque between the pocket and the rolling element increases, and the bearing including the bearing retainer does not rotate smoothly. δ_HOmin/ D_BThe value of or δ_HImin/ D_BExceeds 0.02, the circumferential distance between the rolling element and the pocket surface is too large, and the rolling element collides with the pocket surface with a large force. Therefore, to realize low NRRO, δ_HOmin/ D_BValue and δ_HImin/ D_BIs preferably in the range of 0.01 to 0.02.
[0011]
The invention according to claim 3 is characterized in that the pockets for accommodating and holding the rolling elements are formed at a plurality of positions in the circumferential direction by the inner wall of the pocket, which is formed in an annular shape, and the pocket is formed on one side in the axial direction of each pocket. In a bearing retainer provided with an opening having an opening width smaller than a diameter of a rolling element, at least one of the plurality of pockets has a pocket inner wall in which an inner pocket surface and an outer pocket surface are formed in a radial direction. One of the inner pocket surface and the outer pocket surface is formed with a first spherical pocket surface on the opening side and a first spherical pocket surface on the side opposite to the opening. The center of the radius of curvature of the first spherical pocket surface and the center of the radius of curvature of the second spherical pocket surface are offset from each other by being formed from a second spherical pocket surface connected to the pocket surface. And the other of the inner pocket surface and the outer pocket surface is formed of a part of the inner surface of a cylinder or a cone whose central axis is oriented in the radial direction, and a first cylindrical shape located on the opening side. A second cylindrical pocket surface comprising a pocket surface and a part of the inner surface of a cylinder or a cone whose central axis faces in the radial direction, and which is connected to the first cylindrical pocket surface on the side opposite to the opening; And the center axis of the first cylindrical pocket surface and the center axis of the second cylindrical pocket surface are shifted from each other.
[0012]
According to the third aspect of the present invention, the pocket inner wall is formed by combining the spherical pocket surface formed by a part of the concave surface of the spherical surface and the cylindrical pocket surface formed by the partial concave surface of the cylinder or the cone. Even when the tolerance of the radius of curvature of the spherical surface of the molded spherical pocket surface becomes large, the cylindrical pocket surface can be molded with high accuracy, and the holding between the rotating surface of the rolling element and the pocket surface is possible. The distance in the container circumferential direction is limited within a certain value by the cylindrical pocket surface. For this reason, the size of the gap existing between the rolling element and the pocket is controlled to a certain value or less, and the revolving component of the rolling element in NRRO can be suppressed. Therefore, the revolving component of the rolling elements in the NRRO is more effectively suppressed than in the first or second aspect of the invention.
[0013]
The centers of the radii of curvature of the spherical surfaces forming the first spherical pocket surface and the second spherical pocket surface are offset from each other and are eccentric, and the first spherical pocket surface and the second spherical pocket surface are eccentric. A valley is formed at the boundary portion, and at this boundary portion there is always a gap between the rolling element, and the lubricant can flow through this gap. The center axes of the first and second cylindrical pocket surfaces are offset from each other and eccentric, and the lubricant flows between the rolling elements also at the boundary between the first cylindrical pocket surface and the second cylindrical pocket surface. There are always possible gaps. Further, excess lubricant adhering to the surface of the rolling element is scraped off at the ends of the first spherical pocket surface and the second spherical pocket surface, thereby preventing the dynamic friction torque from becoming excessive. Therefore, the flow of the lubricant is ensured between the inner wall of the pocket and the rolling element, the acoustic life is prevented from being shortened, and the dynamic friction torque can be suppressed low.
[0014]
The invention according to claim 4 is the bearing retainer according to claim 3, wherein a circle formed between the rotating surface of the rolling element and the first spherical pocket surface in a no-load state. Circumferential distance δ_HMinimum value of δ_HminAnd the rotation diameter D of the rolling element_BRatio δ_Hmin/ D_BIs a bearing retainer in which the value range is set to 0.01 to 0.02.
When the rolling element moves in the circumferential direction while rotating in the pocket, and the rolling element contacts the first spherical pocket surface and the second spherical pocket surface, the distance that the rolling element moves in the circumferential direction is δ._HMinimum value of δ_HminIs the distance corresponding to Also, δ_HIs the maximum value δ at the boundary between the first spherical pocket surface and the second spherical pocket surface._HmaxTake. Therefore, δ between the rolling element at this boundary portion_HMaximum value of δ_HmaxAnd the minimum value δ_HminAre at least open, and there is always a gap. The lubricant flows through this gap. Therefore, the distance between the rolling element and the inner wall of the pocket is reduced to suppress the revolving component of the rolling element in the NRRO, and at the same time, the flow of the lubricant is secured between the inner wall of the pocket and the rolling element, and the acoustic life is shortened. Is prevented, and the dynamic friction torque can be kept low.
[0015]
The invention according to claim 5 is characterized in that the pockets for accommodating and holding the rolling elements are formed at a plurality of positions in the circumferential direction by the inner wall of the pocket, which is formed in an annular shape, and the pocket is formed on one side in the axial direction of each pocket. In a bearing retainer provided with an opening having an opening width smaller than a diameter of a rolling element, at least one of the plurality of pockets has an inner pocket surface, an inner pocket surface, an intermediate pocket surface, and an outer pocket. And the inner pocket surface is formed with a first spherical pocket surface on the side of the opening and a first spherical pocket surface on the side opposite to the opening. And the center of the radius of curvature of the first spherical pocket surface and the center of the radius of curvature of the second spherical pocket surface are shifted from each other. The intermediate pocket surface is formed of a part of the inner surface of a cylinder or a cone whose central axis faces in the radial direction, and the first cylindrical pocket surface on the opening side and the cylinder whose central axis faces in the radial direction. Alternatively, the first cylindrical pocket surface is formed by a second cylindrical pocket surface formed of a part of the inner surface of the cone and connected to the first cylindrical pocket surface on the side opposite to the opening. And the center axis of the second cylindrical pocket surface is shifted from each other, and the outer pocket surface is opposite to the third spherical pocket surface on the opening side and the opening. A fourth spherical pocket surface connected to the third spherical pocket surface on the side thereof, and a center of the radius of curvature of the third spherical pocket surface and a radius of curvature of the fourth spherical pocket surface. This is a bearing retainer whose center is shifted from each other.
[0016]
According to the fifth aspect of the present invention, the pocket inner wall includes a spherical pocket surface formed by a part of a spherical concave surface, a cylindrical pocket surface formed by a cylindrical or a concave part of a cone, and a partial concave surface of a spherical surface. The spherical pocket surfaces are formed in order in the radial direction. Since it is possible to mold at least the cylindrical pocket surface with high accuracy, the distance between the rotating surface of the rolling element and the pocket surface in the circumferential direction of the cage can be controlled within a certain value. The revolution component can be suppressed, and the revolution component of the rolling element in the NRRO is more effectively suppressed than the invention described in claim 1 or 2.
[0017]
The centers of the radii of curvature of the spherical surfaces forming the first spherical pocket surface and the second spherical pocket surface are offset from each other and eccentric, and the first cylindrical pocket surface and the second cylindrical pocket surface are eccentric. The central axes are offset and eccentric from each other, and the centers of the radii of curvature of the spherical surfaces forming the third spherical pocket surface and the fourth spherical pocket surface are offset and eccentric from each other. A boundary portion between the second spherical pocket surface, a boundary portion between the first cylindrical pocket surface and the second cylindrical pocket surface, and a boundary portion between the third spherical pocket surface and the fourth spherical pocket surface. In the above, there is always a gap between the rolling element and the gap that allows the lubricant to flow. Further, excess lubricant adhering to the surface of the rolling element is scraped off at the ends of the inner pocket surface and the outer pocket surface, respectively. Therefore, the flow of the lubricant is ensured between the inner wall of the pocket and the rolling element, the acoustic life is prevented from being shortened, and the dynamic friction torque can be suppressed low.
[0018]
The invention according to claim 6 is the bearing retainer according to claim 5, wherein a circle formed between the rotating surface of the rolling element and the first spherical pocket surface in a no-load state. Circumferential distance δ_HIMinimum value of δ_HIminAnd the rotation diameter D of the rolling element_BRatio δ_HImin/ D_BIs set to 0.01 to 0.02, and the circumferential distance δ between the rotating surface of the rolling element and the third spherical pocket surface in a no-load state is set._HOMinimum value of δ_HOminAnd the rotation diameter D of the rolling element_BRatio δ_HOmin/ D_BIs a bearing retainer in which the value range is set to 0.01 to 0.02.
[0019]
When the rolling element moves in the circumferential direction while rotating in the pocket, and the rolling element contacts the first spherical pocket surface and the second spherical pocket surface, the distance that the rolling element moves in the circumferential direction is δ._HIMinimum value of δ_HIminΔ_HIIs the maximum value δ at the boundary between the first spherical pocket surface and the second spherical pocket surface._HImaxTake. Therefore, at least δ between the boundary and the rolling element_HIMaximum value of δ_HImaxAnd the minimum value δ_HIminThere is a distance corresponding to the difference, and a gap always exists. Similarly, at least δ is provided between the rolling element and the boundary between the third spherical pocket surface and the fourth spherical pocket surface._HOMaximum value of δ_HOmaxAnd the minimum value δ_HOminThere is a distance corresponding to the difference, and a gap always exists.
[0020]
Therefore, by reducing the distance between the rolling element and the inner wall of the pocket, the revolving component of the rolling element in the NRRO is suppressed, and at the same time, the flow of the lubricant is secured between the inner wall of the pocket and the rolling element, and the acoustic life is shortened. Is prevented, and the dynamic friction torque can be kept low.
According to a seventh aspect of the present invention, there is provided a bearing having the bearing retainer according to any one of the first to sixth aspects.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
First, the configuration of the present embodiment will be described with reference to FIGS.
FIG. 1 shows an outer shape of a cage 10 for a bearing according to the present embodiment. The retainer 10 is a circular crown-shaped member formed by injection molding using a synthetic resin or the like as a material._CA plurality of pockets 20 are provided at predetermined intervals, and each pocket 20 is separated by a pillar 12. A pair of elastically deformable claws 14 extend from the tip of the column 12 in an arc shape, and an opening 16 of the pocket 20 is formed between the pair of claws 14._AIs open on one side. The opening width of the opening 16 is preferably set in a range of 0.85 to 0.95 times the diameter of the rolling element B.
[0022]
Then, as shown in FIGS. 2 and 3, the inner wall of the pocket 20 has an inner pocket surface 22, an intermediate pocket surface 28, and an outer pocket surface 34 which are in the radial direction L of the cage 10._RThey are arranged in order from inside to outside. The inner pocket surface 22 has two first spherical pocket surfaces 24 connected to the opening 16 between the pair of claws 14, respectively, and a second spherical pocket surface 24 located between the first spherical pocket surfaces 24. And a spherical pocket surface 26. The first spherical pocket surface 24 and the second spherical pocket surface 26 each have a radius of curvature of R_SAnd a spherical concave surface. Center of curvature O of first spherical pocket surface 24₁Is the rotation center O of the rolling element B held and accommodated in the pocket 20 in a no-load state._BAxial direction L_AOf the second spherical pocket surface 26 is unevenly distributed by a distance h to the opposite side to the opening 16 of the second spherical pocket surface 26.₂Is O_BO for₁Are located on the opposite side by a distance h.
[0023]
Also, of the inner pocket surface 22, a boundary portion X between the first spherical pocket surface 24 and the second spherical pocket surface 26._IIn the circumferential direction L of the gap formed between the portion extending from the opening 16 to the opening 16 and the rotating surface of the rolling element B in the unloaded state._CThe distance of δ_HIIt expresses. δ_HIIs the boundary part X_IAt the maximum value δ_HImaxAt the edge of the first spherical pocket surface 24 on the opening 16 side._HIminTake. δ_HIminThe range of values that can be taken is the rotational diameter D of the rolling element B._BIs set in the range of 0.01 times to 0.02 times of the above.
[0024]
Further, the distance between the inner pocket surface 22 and the rotating surface of the rolling element B in a no-load state, and the distance δ in the normal direction to the rotating surface of the rolling element B_VIIs the minimum value δ at the innermost part Y of the pocket 20._VIminTake. Further, the boundary portion X_IAt the distance δ_VITakes the maximum value and its value is δ_HImaxIs equal to
As shown in FIG. 2, the outer pocket surface 34 is configured similarly to the inner pocket surface 22, and has two third spherical pocket surfaces connected to the opening 16 between the pair of claws 14. 36, and a fourth spherical pocket surface 38 located between the third spherical pocket surfaces 36. The spherical surface of which the third spherical pocket surface 36 is a part is the same spherical surface as the spherical surface of which the first spherical pocket surface 24 is a part, and the fourth spherical pocket surface 38 is a part of the spherical surface. The spherical surface is the same spherical surface as the spherical surface of which the second spherical pocket surface 26 is a part. That is, the radius of curvature of the third spherical pocket surface 36 is R_S, Whose center of curvature is O₁And the radius of curvature of the fourth spherical pocket surface 38 is R_S, Whose center of curvature is O₂It is.
[0025]
Similarly to the inner pocket surface 22, a boundary portion X between the third spherical pocket surface 36 and the fourth spherical pocket surface 38 of the outer pocket surface 34 is provided._OIn the circumferential direction L of the gap formed between the portion extending from the opening 16 to the opening 16 and the rotating surface of the rolling element B in the unloaded state._CThe distance of δ_HOIt expresses. δ_HOIs the boundary part X_OAt the maximum value δ_HOmaxAt the edge of the third spherical pocket surface 36 on the opening 16 side._HOminTake. δ_HOminThe range of values that can be taken is the rotational diameter D of the rolling element B._BIs set in the range of 0.01 times to 0.02 times of the above.
[0026]
Furthermore, δ_VIIs the distance between the outer pocket surface 34 and the rotating surface of the rolling element B in the unloaded state, and the distance δ in the normal direction to the rotating surface of the rolling element B._VOIs the minimum value δ at the innermost part Y of the pocket 20._VOminTake. Further, the boundary portion X_OAt the distance δ_VOIs maximum and its value is δ_HOmaxIs equal to
As shown in FIGS. 2 and 4, the inner wall of the intermediate pocket surface 28 has a first cylindrical pocket surface 30 connected to the opening 16 between the pair of claws 14, and a first cylindrical pocket surface 30. And a second cylindrical pocket surface 32 located between the pocket surfaces 30. Radial direction L of first cylindrical pocket surface 30_RThe inner edge is continuous with the edge of the first spherical pocket surface 24, and the radial direction L of the second cylindrical pocket surface 32._RThe inner edge is continuous with the edge of the second spherical pocket surface 26. Similarly, the radial direction L of the first cylindrical pocket surface 30 and the second cylindrical pocket surface 32_REach outer edge is continuous with the edge of the third spherical pocket surface 36 and the edge of the fourth spherical pocket surface 38, respectively.
[0027]
The first cylindrical pocket surface 30 and the second cylindrical pocket surface 32 each have a radius of R_MAnd a curved surface which forms a part of the inner surface of a cylinder having a circular cross-section._RIs facing. The center of curvature O of the circular cross section of the cylinder forming the first cylindrical pocket surface 30_M1Is O₁, The center of rotation O of the rolling element B_BAxial direction L_AThe center of curvature O of the circular cross section of the cylinder forming the second cylindrical pocket surface 32_M2Is O₂Like O_BO for_M1Are located on the opposite side by a distance h. Accordingly, the central axes of the respective cylinders are separated from each other by a distance 2h. Note that O_M1O on the central axis of the cylinder passing through₁Exists and O_M2O on the central axis of the cylinder passing through₂Exists.
[0028]
Further, the intermediate pocket surface 28 is moved in the radial direction L_R, The distance between the rolling element B and the rotating surface of the rolling element B in an unloaded state, and the normal distance δ to the rotating surface of the rolling element B_VMIs the radial direction L_RFrom the outermost and innermost sides toward the center. δ_VMIs the radial direction L of the second cylindrical pocket surface 32 at the innermost portion Y of the pocket 20._RMinimum value δ at the center of width_VMminTake. Further, the intermediate pocket surface 28 is set in the circumferential direction L of the cage 10._C, The connecting portion X between the second cylindrical pocket surface 32 and the first cylindrical pocket surface 30_MΔ_VMIs getting bigger. δ_VMIs the boundary part X_MRadial direction L_RMaximum value δ at both ends of_VMmaxAnd its value is δ_HImaxIs equal to
[0029]
Also, the boundary portion X in the intermediate pocket surface 28_MIn the circumferential direction L of the gap formed between the portion extending from the opening 16 to the opening 16 and the rotating surface of the rolling element B in the unloaded state._CThe distance of δ_HMIt expresses. δ_HMIs the boundary part X_MAt the maximum value δ_HMmaxAt the edge of the first cylindrical pocket surface 30 on the opening 16 side._HMminTake.
[0030]
FIG. 5 shows that the pocket 20 is connected to the rotation center O of the rolling element B._BRadial direction L passing through_R2 shows a vertical cross section of FIG. The innermost part Y of the pocket 20 is on this vertical section. Then, the radial direction L of the intermediate pocket surface 28_RAssuming that W is the width and length, the following equations (1) and (2) are geometrically established.
R_M= D_B/ 2 + h + δ_VMmin… (1)
R_S= ｛R_M ²+ (W / 2)²｝^1/2… (2)
This embodiment is configured as described above, and its operation will be described next.
[0031]
When the rolling element B is inserted into the pocket 20 of the retainer 10, the rolling element B is pushed through the opening 16. The pair of claws 14 are moved in the circumferential direction L by the rolling elements B._CThe rolling element B passes through the opening 16 and fits in the pocket 20. When a bearing (not shown) incorporating the cage 10 for accommodating and holding the rolling element B in each pocket 20 rotates, the rolling element B rotates in the pocket 20 under a load.
[0032]
Further, the rolling element B rotates, and the circumferential direction L of the cage 10 in the pocket 20 is changed._C, The rotating surface of the rolling element B comes into contact with the inner wall of the pocket 20. First, a state in which the rolling element B is in contact with the first cylindrical pocket surface 30 and the second cylindrical pocket surface 32 is considered. At this time, the rotating surface of the rolling element B comes into contact with the end of the first cylindrical pocket surface 30 on the opening 16 side, and the rolling element B is rotated as compared with the case where the rolling element B is rotating under no load. B is the circumferential direction L_CTo δ_HMminOnly moving. X_MIn X_MFrom the rotating surface of the rolling element B to δ_HMmax−δ_HMminThere is a gap of length. This gap serves as a lubricant pool, and the flow of the lubricant between the rolling element B and the intermediate pocket surface 28 is not impaired.
[0033]
The same applies to the case where the rolling element B comes into contact with the first spherical pocket surface 24 and the second spherical pocket surface 26._IFrom the rotating surface of the rolling element B to δ_HImax−δ_HImin, And there is a gap, and this gap becomes a lubricant pool, and the flow of the lubricant between the rolling element B and the inner pocket surface 22 is not impaired.
[0034]
The same applies to the case where the rolling element B contacts the third spherical pocket surface 36 and the fourth spherical pocket surface 38._OFrom the rotating surface of the rolling element B to δ_HOmax−δ_HOmin, And there is a gap, and the gap forms a lubricant pool, and the flow of the lubricant between the rolling element B and the outer pocket surface 34 is not impaired.
[0035]
In addition, it is relatively difficult to mold a concave surface formed by a part of the inner surface of the spherical surface with high accuracy, but it is relatively easy to mold a concave surface formed by a part of the inner surface of the cylinder with high accuracy, and the accuracy is easily managed. For this reason, the radius of curvature R of the spherical surface forming the first spherical pocket surface 24, the second spherical pocket surface 26, the third spherical pocket surface 36, and the fourth spherical pocket surface 38._SIt is possible to finish the first cylindrical pocket surface 30 and the second cylindrical pocket surface 32 with high accuracy even if the finishing accuracy varies. Therefore, even when the finishing accuracy of the first spherical pocket surface 24, the second spherical pocket surface 26, the third spherical pocket surface 36, and the fourth spherical pocket surface 38 is poor, the pocket 20 is not required. The amount of movement of the rolling element B in the inside is suppressed by the intermediate pocket surface 28, and it is easy to manage the distance between the rolling element B and the inner wall of the pocket 20 to a predetermined value or less.
[0036]
Excess lubricant adhering to the surface of the rolling element B is removed from the inner pocket surface 22 in the radial direction L._RRadial direction L of inner end and outer pocket surface 34_REach is scraped off with the outer edge. Therefore, the adverse effect that the excess lubricant adheres to the rolling elements B and the dynamic friction torque increases is prevented.
Therefore, the bearing retainer 10 according to the present embodiment allows an appropriate amount of lubricant to flow between the inner wall of the pocket 20 and the rolling element B, thereby preventing an increase in dynamic friction torque and an acoustic life. Is prevented from decreasing. In addition, the distance between the rolling element B and the inner wall of the pocket 20 does not increase, and the revolving component of the rolling element in NRRO is suppressed.
[0037]
Further, when a bearing having the bearing retainer 10 according to the present embodiment is configured, in this bearing, the revolving component of the rolling element in the NRRO is suppressed.
In this embodiment, the pocket 20 is formed by the inner pocket surface 22, the intermediate pocket surface 28, and the outer pocket surface 34. However, the pocket 20 is formed by the inner pocket surface 22 and the intermediate pocket surface 28. It is also possible. In addition, the pocket 20 can be formed by the intermediate pocket surface 28 and the outer pocket surface 34.
[0038]
In addition, the first cylindrical pocket surface 30 and the second cylindrical pocket surface 32 are formed of curved surfaces forming a part of the inner surface of the cylinder, but are formed by curved surfaces forming a part of the inner surface of the cone. Is also possible.
Next, FIG. 6 shows a verification result of an effect achieved by the bearing retainer according to the present embodiment with respect to a reduction in the revolving component of the rolling element in NRRO.
[0039]
In this verification, the bearing cage according to the present embodiment (example of the present invention) and a conventional bearing cage (comparative example) were used within the tolerance of the pocket dimensions of each cage. The resulting NRRO rolling element revolution component was measured.
First, the cage used in the example of the present invention had the same configuration as the bearing cage according to the present embodiment, and had dimensions of an inner diameter of 5 mm, an outer diameter of 13 mm, and a width of 4 mm in the radial direction. And, the rotational speed is 7200 min.^-1Then, an axial load of 11.8 N was applied, and the rolling element revolution component of NRRO was measured in each case where the dimensions of the pocket were the maximum value, the minimum value, and the median value of the tolerance.
[0040]
Further, the cage used in the comparative example is different from the cage used in the example of the present invention in that the pocket has no intermediate pocket surface, the other configuration is the same, and the dimensions are the same as those of the example of the present invention. It is the same as a container. And, the rotational speed is 7200 min.^-1An axial load of 11.8 N was applied, and the rolling element revolution component of the NRRO was measured in each case where the dimensions of the pocket were the maximum value, the minimum value, and the median value of the tolerance.
[0041]
The vertical axis in FIG. 6 shows the rolling element revolution component of NRRO. When the dimension of the pocket is the maximum value of the tolerance, the rolling element revolution component of the NRRO was 15 nm in the example of the present invention, and was 22 nm in the comparative example. In the present invention example and the comparative example, the rolling element revolution components of the NRRO at the minimum value and the median value of the tolerance were 3 nm and 10 nm, and both examples had the same value. Therefore, it is understood that the example of the present invention can suppress the maximum value of the rolling element revolution component of the NRRO to a lower value.
[0042]
Next, δ_HImin/ D_BAnd δ_HOmin/ D_BFIG. 7 shows the results of a test performed to determine the optimum range of. Circumferential direction L between the inner wall of the pocket and the rolling surface of the rolling element_CDistance δ_HMinimum value of δ_HminAnd the rolling diameter D of the rolling element_BRatio δ_Hmin/ D_BAnd the dynamic friction torque and the rolling element revolution component of NRRO were measured.
[0043]
The horizontal axis in FIG. 7 is δ_Hmin/ D_BThe right vertical axis shows the rolling element revolution component of the NRRO, and the left vertical axis shows the dynamic friction torque. δ_Hmin/ D_BIs less than 0.01, the dynamic friction torque sharply increases, and δ_Hmin/ D_BExceeds 0.02, the revolution component of the rolling element of the NRRO rapidly increases. Therefore, in order to reduce the dynamic friction torque and the rolling element revolution component of NRRO,_Hmin/ D_BIs set to 0.01 or more and 0.02 or less. That is, δ_HImin/ D_BIs in the range of 0.01 to 0.02, and δ_HOmin/ D_BIs in the range of 0.01 or more and 0.02 or less.
[0044]
【The invention's effect】
Since the present invention is a bearing retainer and a bearing as described above, the revolving component of the rolling element of the NRRO is ensured while ensuring the flow of the lubricant between the rolling element and the pocket surface that houses and holds the rolling element. There is an effect that a bearing cage and a bearing that can be suppressed can be provided.
[Brief description of the drawings]
FIG. 1 is a perspective view of a cage according to an embodiment of the present invention.
FIG. 2 is a perspective view of a pocket of the retainer according to the present embodiment.
FIG. 3 is a diagram showing a shape of an inner pocket surface of the cage according to the present embodiment.
FIG. 4 is a diagram showing a shape of an intermediate pocket surface of the cage according to the present embodiment.
FIG. 5 is a vertical longitudinal sectional view of a pocket of the cage according to the present embodiment.
FIG. 6 is a diagram showing results of verification of the effect of the cage according to the present embodiment.
FIG. 7_Hmin/ D_BFIG. 4 is a diagram showing the relationship between dynamic friction torque, and rolling element revolution components of NRRO.
[Explanation of symbols]
10cm cage
12 pillar
14 nail
16mm opening
20 pocket
22mm inside pocket surface
24 ° first spherical pocket surface
26 ° second spherical pocket surface
28 middle pocket surface
30 ° first cylindrical pocket surface
32 ° second cylindrical pocket surface
34 outer pocket surface
36 ° third spherical pocket surface
38 ° fourth spherical pocket surface
B rolling element
O_BRolling element rotation center
D_B回 転 Rolling element rotation diameter
O₁中心 Center of curvature of the first and third spherical pocket surfaces
O₂中心 Center of curvature of the second and fourth spherical pocket surfaces
O_M1中心 Center of curvature of the circle that forms the cross section of the first cylindrical pocket surface
O_M2中心 The center of curvature of the circle that forms the cross section of the second cylindrical pocket surface
R_S半径 Radius of curvature of spherical pocket surface
R_M半径 Radius of curvature of circular cross section of cylindrical pocket surface
δ_HI距離 Circumferential distance between rolling surface of rolling element and inner pocket surface
δ_HImax最大 Maximum circumferential distance between the rotating surface of the rolling element and the inner pocket surface
δ_HImin最小 Minimum circumferential distance between the rotating surface of the rolling element and the inner pocket surface
δ_HO距離 Circumferential distance between rolling surface of rolling element and outer pocket surface
δ_HM距離 Circumferential distance between rolling surface of rolling element and intermediate pocket surface
δ_HMmax最大 Maximum circumferential distance between the rotating surface of the rolling element and the intermediate pocket surface
δ_HMmin最小 Minimum circumferential distance between the rolling surface of the rolling element and the intermediate pocket surface
X_I接 続 Connecting portion between the second spherical pocket surface and each first spherical pocket surface
X_O(4) A connection portion between the fourth spherical pocket surface and each third spherical pocket surface
X_M接 続 Connecting portion between the second cylindrical pocket surface and each of the first cylindrical pocket surfaces
The innermost part of Y pocket
W Radial width of intermediate pocket surface
L_AAxial direction of cage
L_RRadial direction of cage
L_CCircumferential direction

Claims (7)

A plurality of pockets for accommodating and holding the rolling elements are formed at a plurality of locations in the circumferential direction by a pocket inner wall having a concave surface, and the opening is formed on one side in the axial direction of each pocket with a diameter larger than the diameter of the rolling elements. In a bearing cage with an opening with a small width,
The pocket inner wall of at least one of the plurality of pockets is formed such that an inner pocket surface and an outer pocket surface are arranged in the radial direction,
Forming the inner pocket surface from a first spherical pocket surface on the opening side and a second spherical pocket surface continuous with the first spherical pocket surface on the side opposite to the opening; The center of the radius of curvature of the first spherical pocket surface and the center of the radius of curvature of the second spherical pocket surface are offset from each other;
The outer pocket surface is formed by a third spherical pocket surface on the opening side and a fourth spherical pocket surface continuous with the third spherical pocket surface on the side opposite to the opening, A bearing retainer wherein the center of the radius of curvature of the third spherical pocket surface and the center of the radius of curvature of the fourth spherical pocket surface are shifted from each other. 2. The bearing cage according to claim 1, wherein a circumferential distance δ _HI formed between a rotating surface of the rolling element in a no-load state and the first spherical pocket surface is determined. 3. and a minimum value [delta] _Himin, the range of values of the ratio [delta] _Himin / _{D B} between the rotation diameter _{D B} of the rolling element is set to 0.01 to 0.02,
The ratio of the rotation surface of the rolling element in the unloaded condition, and the minimum value [delta] _Homin circumferential distance [delta] _HO between the third spherical pocket surface, the rotation diameter D _B of the rolling element bearing retainer, characterized in that setting the range of values of δ _HOmin / _{D B} 0.01 to 0.02. A plurality of pockets for accommodating and holding the rolling elements are formed at a plurality of locations in the circumferential direction by a pocket inner wall having a concave surface, and the opening is formed on one side in the axial direction of each pocket with a diameter larger than the diameter of the rolling elements. In a bearing cage with an opening with a small width,
The pocket inner wall of at least one of the plurality of pockets is formed such that an inner pocket surface and an outer pocket surface are arranged in the radial direction,
One of the inner pocket surface and the outer pocket surface is connected to a first spherical pocket surface on the opening side and a second spherical pocket surface on the opposite side to the opening. A center of the radius of curvature of the first spherical pocket surface and a center of the radius of curvature of the second spherical pocket surface.
The other of the inner pocket surface and the outer pocket surface, a central axis is formed of a part of the inner surface of a cylinder or cone whose radial direction is oriented in the radial direction, and a first cylindrical pocket surface on the opening side, A central axis is formed of a part of the inner surface of a cylinder or a cone facing in the radial direction, and is formed from a second cylindrical pocket surface continuous with the first cylindrical pocket surface on the side opposite to the opening. The center axis of the first cylindrical pocket surface and the center axis of the second cylindrical pocket surface are offset from each other. 4. The bearing retainer according to claim 3, wherein a circumferential distance δ _H formed between the rotating surface of the rolling element and the first spherical pocket surface in a no-load state is set. 5. and a minimum value [delta] _Hmin, bearing retainer, characterized in that set to 0.01 to 0.02 to the range of values of the ratio [delta] _Hmin / _{D B} between the rotation diameter _{D B} of the rolling element. A plurality of pockets for accommodating and holding the rolling elements are formed at a plurality of locations in the circumferential direction by a pocket inner wall having a concave surface, and the opening is formed on one side in the axial direction of each pocket with a diameter larger than the diameter of the rolling elements. In a bearing cage with an opening with a small width,
The pocket inner wall of at least one of the plurality of pockets has an inner pocket surface, an intermediate pocket surface, and an outer pocket surface formed in order in the radial direction,
Forming the inner pocket surface from a first spherical pocket surface on the opening side and a second spherical pocket surface continuous with the first spherical pocket surface on the side opposite to the opening; The center of the radius of curvature of the first spherical pocket surface and the center of the radius of curvature of the second spherical pocket surface are offset from each other;
A cylinder having a central axis oriented in a radial direction, a part of the inner surface of a cylinder or a cone, and a first cylindrical pocket surface located on the opening side and a cylinder oriented in a radial direction; Alternatively, the first cylindrical pocket surface is formed by a second cylindrical pocket surface which is formed of a part of the inner surface of the cone and is continuous with the first cylindrical pocket surface on the side opposite to the opening. And the center axis of the second cylindrical pocket surface is shifted from each other,
The outer pocket surface is formed by a third spherical pocket surface on the opening side and a fourth spherical pocket surface continuous with the third spherical pocket surface on the side opposite to the opening, A bearing retainer wherein the center of the radius of curvature of the third spherical pocket surface and the center of the radius of curvature of the fourth spherical pocket surface are shifted from each other. 6. The bearing retainer according to claim 5, wherein a circumferential distance δ _HI formed between the rotating surface of the rolling element in a no-load state and the first spherical pocket surface. and a minimum value [delta] _Himin, the range of values of the ratio [delta] _Himin / _{D B} between the rotation diameter _{D B} of the rolling element is set to 0.01 to 0.02,
The ratio of the rotation surface of the rolling element in the unloaded condition, and the minimum value [delta] _Homin circumferential distance [delta] _HO between the third spherical pocket surface, the rotation diameter D _B of the rolling element bearing retainer, characterized in that setting the range of values of δ _HOmin / _{D B} 0.01 to 0.02. A bearing comprising the bearing retainer according to any one of claims 1 to 6.

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