JP2007333084A - Cage for bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cage for a bearing capable of setting a large load capacity without lowering its strength, and controlling deformation in rotating the bearing. <P>SOLUTION: This cage 11 for the bearing moving along the inside of the bearing with a plurality of rolling elements while rotatably holding the plurality of rolling elements (conical rollers 5) in the bearing, comprises at least one annular portion 2, 4 continued in the circumferential direction along the inside of the bearing, a plurality of pillars 6 extending along the inside of the bearing from the annular portions and arranged at prescribed intervals in the circumferential direction along the annular portions, and a plurality of pockets 8 defined by inner peripheral faces 2s, 4s of the annular portions and inner wall faces 6s of the plurality of pillars and rotatably holding the plurality of rolling elements one by one, and a window angle θ between the inner wall faces of two pillar portions defining each pocket is determined to be 44-60°. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bearing cage capable of setting a large load capacity without reducing strength and capable of suppressing deformation during rotation of the bearing.

  2. Description of the Related Art Conventionally, various types of bearings that rotatably support a rotating mechanism are applied to industrial machines such as railway vehicles, automobiles, steel facilities, and construction machines. As such a bearing, there are a ball bearing that is applied when supporting a relatively small load and a roller bearing that is applied when supporting a relatively large load, which corresponds to high-speed rotation under a high load in recent years. For this reason, roller bearings are often used.

  As an example of a roller bearing, the tapered roller bearing shown in FIGS. 1 (a) and 1 (b) is formed on opposing surfaces of an inner ring 1 and an outer ring 3, and inner and outer rings 1 and 3, which are arranged so as to be relatively rotatable. A plurality of rolling elements 5 rotatably incorporated between the raceway surfaces 1s and 3s, and a holder 11 having a plurality of pockets 8 for rotatably holding the plurality of rolling elements 5 one by one. It is configured. In this case, it is assumed that each rolling element 5 is a tapered roller 5 whose rolling surface 5m (the surface rolling between the raceway surfaces 1s and 3s) has a tapered shape, and holds the tapered roller. As the vessel 11, a cage retainer 11 is used.

  The cage retainer 11 includes two annular portions 2, 4 which are continuous in the circumferential direction between the inner and outer rings 1, 3 and are opposed to each other at a predetermined interval at the same center. 2 and 4 and a plurality of column portions 6 arranged at equal intervals in the circumferential direction along the annular portions 2 and 4, and the inner peripheral surface 2s of the two annular portions 2 and 4 , 4s (FIG. 1 (a)) and a plurality of pockets 8 defined by inner wall surfaces 6s (FIG. 1 (e)) on both sides of the plurality of column portions 6. In this case, the two annular portions 2, 4 are designed to have different diameters along the inclination direction of the raceway surfaces 1s, 3s of the inner and outer rings 1, 3. That is, one annular portion (large diameter side annular portion) 4 is designed to have a relatively larger diameter than the other annular portion (small diameter side annular portion) 2. The whole forms, for example, a truncated cone shape as shown in FIG.

  In such a cage retainer 11, a plurality of tapered rollers 5 are rotatably held one by one in each pocket 8 of the retainer 11. That is, in each tapered roller 5, its rolling surface 5m is held by the inner wall surface 6s of two adjacent column parts 6, and the circular side surfaces 5e formed on both sides of the rolling surface 5m are two annular rings. The inner peripheral surfaces 2s and 4s of the portions 2 and 4 are held. During the rotation of the bearing, the cage retainer 11 revolves along the space between the inner and outer rings 1 and 3 together with the tapered rollers 5 while holding the tapered rollers 5 one by one in the plurality of pockets 8. To do.

  In this case, in order to keep the rotational performance of the tapered roller 5 held in each pocket 8 constant during the revolution of the cage retainer 11, for example, Patent Document 1 discloses a window angle θ (see FIG. 1) of each pocket 8. A cage in which (e)) is set to 55 ° or more and 80 ° or less has been proposed. Here, as shown in FIG. 1 (e), the window angle θ is an angle formed between the inner wall surfaces 6 s of the two pillar portions 6 that define each pocket 8, and depends on the size of the window angle θ. Thus, the contact state between the rolling surface 5 m of the tapered roller 5 held in the pocket 8 and the inner wall surface 6 s of each column portion 6 adjacent to the tapered roller 5 is maintained well. Further, the window angle θ is tapered from the inner diameter side of the cage retainer 11 to the outer diameter side (that is, from the inner diameter surface 6in to the outer diameter surface 6out of the column portion 6), and during the rotation of the bearing. The tapered roller 5 is prevented from being detached from each pocket 8 by the acting centrifugal force.

  By the way, depending on the purpose and environment of use of the bearing, it may be necessary to set a large load capacity of the bearing. In this case, the number of the tapered rollers 5 that can be held may be increased by increasing the number of pockets 8. When the number of pockets 8 is increased, it is necessary to increase the number of the column parts 6 by the increased amount. However, when this happens, each column part 6 must be thinned, and as a result, the entire cage retainer 11 The strength of the will decrease. Therefore, there is a certain limit to the thickness reduction of each column part 6. Therefore, in order to increase the number of pockets 8 without reducing the thickness of each column portion 6 (that is, while ensuring a large section modulus of each column portion 6), each column portion 6 is moved toward the outer ring 3 side. The overall diameter of the cage retainer 11 may be increased. The section modulus refers to a value obtained by dividing the sectional secondary moment with respect to the centroid axis (the center of the section) of the column portion 6 by the distance from the centroid axis to the farthest point in the section.

  However, in the configuration in which each column portion 6 is brought closer to the outer ring 3 side, the window angle θ of each pocket 8 is geometrically large, which may cause the following problems. That is, during the rotation of the bearing, the radial contact pressure between the inner wall surface 6s of each column 6 and the rolling surface 5m of the tapered roller 5 increases, so that depending on the magnitude of the contact pressure, the cage shape The cage 11 may be deformed in the radial direction. In this case, depending on the degree of deformation, the outer diameter side of the retainer 11 (particularly, the outer diameter surface 6out of the column portion 6) strongly interferes with the raceway surface 3s of the outer ring 3 (for example, collision, sliding contact). There is a risk of doing.

As a result, it becomes difficult to smoothly revolve the retainer 11 as the bearing rotates, and as a result, it becomes difficult to maintain the rotational performance (for example, rotational stability, rotational smoothness) of the bearing constant. End up. Further, depending on the degree of interference between the outer diameter side of the retainer 11 (outer diameter surface 6out of the column portion 6) and the raceway surface 3s of the outer ring 3, the wear and wear of the interference portion are promoted. It becomes difficult to extend the life of the product. Furthermore, in the case where the entire cage retainer 11 is formed of a resin material, the retainer 11 greatly expands as the temperature around the bearing increases during the rotation of the bearing, and as a result, Such interference may increase. Particularly in applications where the bearing is used at high speed rotation, the cage 11 is further expanded by the application of centrifugal force, and the interference is further promoted.
JP 2005-188738 A

  The present invention has been made in order to solve such problems, and the object thereof is to maintain a bearing that can set a large load capacity without reducing strength and can suppress deformation during rotation of the bearing. Is to provide a vessel.

In order to achieve such an object, the present invention is a bearing retainer that revolves along the inside of the bearing together with the plurality of rolling elements while rotatably holding the plurality of rolling elements inside the bearing, At least one annular portion that is continuous in the circumferential direction along the inside of the bearing, and a plurality of column portions that extend from the annular portion along the inside of the bearing and are arranged at predetermined intervals in the circumferential direction along the annular portion And a plurality of pockets which are partitioned by the inner peripheral surface of the annular portion and the inner wall surfaces of the plurality of column portions and rotatably hold the plurality of rolling elements one by one. The window angle formed between the inner wall surfaces of the two column portions is set to 44 ° or more and 60 ° or less.
In this case, in each pocket, a roller can be rotatably held as a rolling element. Further, the entire cage is formed of a resin material.

  According to the bearing cage of the present invention, by setting the window angle of each pocket of the cage to 44 ° or more and 60 ° or less, the load capacity can be set large without reducing the strength, Deformation during bearing rotation can be suppressed.

  Hereinafter, a bearing cage according to an embodiment of the present invention will be described with reference to the accompanying drawings. The present embodiment is an improvement of the cage retainer 11 used for the roller bearing (FIGS. 1A and 1B) as described above, and the other configurations are the same as those shown in FIG. Therefore, hereinafter, the description will be limited to the cage 11 of the improved portion.

  As shown in FIGS. 1C and 1D, in the bearing retainer according to the present embodiment, the window angle θ formed between the inner wall surfaces of the two pillar portions that define each pocket (FIG. 1E). ) Is set to 44 ° or more and 60 ° or less. According to this, as the window angle is increased from the minimum θmin = 44 ° (FIG. 1 (c)) to the maximum θmax = 60 ° (FIG. 1 (d)), each column portion 6 approaches the outer ring 3 side. Thus, the number of pockets 8 of the cage retainer 11 can be increased. In this case, the number of tapered rollers 5 that can be held in the retainer 11 can be increased without reducing the thickness of each column 6 (that is, while ensuring a large section modulus of each column 6). The strength of the cage 11 is not reduced. As a result, the load capacity of the bearing in which the cage 11 is incorporated with the tapered roller 5 can be increased.

  Further, according to the present embodiment, during the rotation of the bearing, the contact pressure in the radial direction between the inner wall surface 6s of each column portion 6 and the rolling surface 5m of the tapered roller 5 is determined by a conventional technique (for example, Patent Documents). Compared with 1), it can be reduced by about 20% or more. Thereby, the deformation | transformation to the radial direction of the cage retainer 11 can be suppressed. As a result, the conventional problem that the outer diameter side of the retainer 11 (particularly, the outer diameter surface 6out of the column portion 6) interferes with the raceway surface 3s of the outer ring 3 (for example, collision or sliding contact) is solved. be able to. In this case, since the cage retainer 11 can be smoothly revolved as the bearing rotates, it becomes possible to maintain the bearing rotational performance (for example, rotational stability, rotational smoothness) constant, and the bearing life. Can be extended.

  Furthermore, according to the present embodiment, in the specification in which the entire cage retainer 11 is formed of a resin material, even if the retainer 11 is thermally expanded as the temperature rises around the bearing during rotation of the bearing, The degree of interference with the raceway surface 3s of the outer ring 3 can be significantly reduced. The same applies to applications in which the bearing is used at high speed rotation.

  The resin material applicable to the bearing cage of the present embodiment is not limited to the kind thereof, but, for example, polyamide 6 (PA6), polyamide 66 (PA66), polyamide 11 (PA11), polyamide 12 ( PA12), polyamide 46 (PA46), polybutylene terephthalate (PBT), polyoxymethylene (POM), polytetrafluoroethylene (PTFE), polyarylate (PAR), polyethersulfone (PES), polyphenylene sulfide (PPS), Examples include polyetherimide (PEI), polyamideimide (PAI), polyetheretherketone (PEEK), and polyimide (PI).

  In addition, since the cage 11 of the present embodiment is a tapered roller bearing that holds a plurality of tapered rollers 5, the cage 11 is configured so that each tapered roller 5 ( In particular, it is in a state of leaning on the upper side of FIGS. 1 (a) and 1 (b). When the bearings (inner and outer rings 1, 3) are rotated in this state, each tapered roller 5 rotates while pushing each column part 6, so that the column part 6 has a window angle θ (FIG. 1 (e)). The pressing force acts. At this time, a frictional force acts between the rolling surface 5 m of the tapered roller 5 and the inner wall surface 6 s of the column portion 6, but when the frictional force becomes larger than a force for pushing back the tapered roller 5 (that is, When in a non-lubricated state), the tapered roller 5 and the column portion 6 may bite into each other in each pocket 8.

Here, the relationship between the window angle θ formed between the inner wall surfaces 6s of the two pillars 6 that define each pocket 8 and the static friction coefficient μ is expressed by the following equation (1). The biting phenomenon as described above occurs.
μ ≧ tan θ / 2 (1)
In this case, in the material of the cage 11, the material having a coefficient of static friction (against steel) at the time of drying of 0.4 or less also has a tapered roller 5 and a column portion 6 as long as the window angle θ is 44 ° or more. The occurrence of the biting phenomenon can be avoided.

  The resin material of the cage 11 described above has a coefficient of static friction (against steel) at the time of drying of 0.4 or less. In the cage 11 using such a resin material, the window angle θ of each pocket 8 is 44 ° or more. Thus, even when the non-lubricated state as described above occurs during rotation of the bearing, the occurrence of the biting phenomenon between the tapered roller 5 and the column portion 6 can be avoided.

On the other hand, if the window angle θ of each pocket 8 is set large, the contact pressure (pressing force) in the radial direction between the inner wall surface 6s of each column 6 and the rolling surface 5m of the tapered roller 5 increases. Depending on the magnitude of the pressing force, the cage retainer 11 may be deformed in the radial direction. The amount of deformation of the cage 11 varies depending on the size and number of the tapered rollers 5, the diameter (PCD) of a virtual circle formed by connecting the centers of the tapered rollers 5, and the use state and environment of the bearing. to, can not be said sweepingly, when these conditions constant, the relationship between the window angle θ and the pressing force F _R is expressed by the following equation (2).
F _R = F _C × sin θ / 2 (2)
F _C : Contact force in the circumferential direction of the tapered roller 5

  In this case, by setting the window angle θ to 60 ° or less, the pressing force (contact pressure) in the radial direction can be reduced by about 20% or more compared to 80 ° which is the upper limit of the conventional window angle. Thereby, it becomes possible to suppress the deformation | transformation to the radial direction of the cage retainer 11, and the outer diameter side (especially outer diameter surface 6out of the column part 6) of the said retainer 11 is on the track surface 3s of the outer ring | wheel 3. On the other hand, conventional problems such as interference (for example, collision and sliding contact) can be solved.

  In the above-described embodiment, a tapered roller is assumed as the rolling element 5 and the cage 11 that can hold the tapered roller 11 is described. However, other than this, for example, a cylindrical roller, a needle roller, a spherical roller, a convex surface The effects as described above can be realized by applying the technical configuration of the present invention to the retainer 11 that can retain rollers and the like.

  Further, as the cage 11 according to the modified example of the present invention, for example, as shown in FIG. 2A, adjacent to both end portions 6 e of the column portion 6 in the annular portions 2 and 4 at the four corners of each pocket 8. You may provide the escape part 10 formed in the part which was depressed by predetermined depth. In this case, the relief portions 10 are provided at the four corners of each pocket 8 and are formed to be recessed (recessed) in the direction along the rotation center axis Q of the bearing (FIG. 1A). In other words, each relief portion 10 is not formed to be recessed (recessed) along the bearing rotation direction.

  More specifically, as shown in FIGS. 2B to 2D, the relief portion 10 includes a flat surface 10s formed flat across the annular portions 2 and 4 and a flat surface. It is composed of two arcuate surfaces R1 and R2 that are continuous with a predetermined curvature (for example, a radius of curvature) from both sides of the surface 10s toward the annular portions 2 and 4 and the column portion 6. Here, the flat surface 10s is formed so as to cross the annular portions 2 and 4 in parallel along the direction orthogonal to the rotation center axis of the bearing, and one of the two arc-shaped surfaces R1 and R2. The arcuate surface R1 is continuous from one side of the flat surface 10s to the inner peripheral surfaces 2s and 4s of the annular portions 2 and 4, and the other arcuate surface R2 is from the other side of the flat surface 10s. It is continuous with the inner wall surface 6 s of the column portion 6.

  In such a relief portion 10, assuming that the overall width dimension from the two arcuate surfaces R1 and R2 to one flat surface 10s is 2n, the width dimension 2n is the end face of the tapered roller 5 (the rolling surface 5m). Is set larger than the dimension (FIG. 1A) of the chamfer 5r formed on the annular end face that is continuous along the circumferential direction between the side face 5e and the side face 5e. Further, the relief portion 10 is configured by setting the depth dimension k within a range of 10% to 30% of the width dimension H of the annular portions 2 and 4. Here, assuming that the depth dimension k of the relief portion 10 approximates the curvature radius ρ of the arcuate surfaces R1 and R2 (ρ = k), the ratio (ρ / H) of the curvature radius ρ and the width dimension H In terms of representation, the clearance 10 is set so as to satisfy the relationship of 0.1 ≦ ρ / H ≦ 0.3.

  In the drawing, each of the arcuate surfaces R1 and R2 is formed with a continuous constant (single) radius of curvature ρ. In this case, the magnitude of the radius of curvature ρ is, for example, the depth of the relief portion 10. Since it is arbitrarily set according to the length dimension k and the width dimension 2n, the numerical value is not particularly limited here. Further, the depth dimension k and the width dimension 2n of the relief portion 10 are arbitrary depending on, for example, the size and shape of a rolling element (cone roller) (not shown) and the size and shape of the pocket 8 that holds the rolling element (cone roller). Therefore, the numerical value is not particularly limited here.

  As described above, according to the cage 11 of this modification, the cage 11 is composed of two arcuate surfaces that are continuous with a predetermined radius of curvature ρ from both sides of one flat surface 10s toward the annular portions 2 and 4 and the column portion 6. By providing the relief portions 10 at the four corners of the pocket 8, excessive stress concentration at the four corners of the pocket 8 can be reduced even under a condition in which an increase in the radius of curvature is restricted. As a result, the strength of the cage 11 can be kept constant as compared with the conventional case. As a result, the life of the cage 11 can be extended and the reliability can be improved.

  Further, according to this modification, the width dimension 2n of the relief portion 10 is set to be larger than the dimension of the chamfer 5r of the tapered roller 5, thereby preventing the lubricant (grease, oil) sealed in the bearing from being scraped off. Further, uneven wear of the pocket 8 of the cage can be prevented. That is, at the four corners of each pocket 8, it becomes possible to adhere and hold the lubricant to the end face of the tapered roller 5, whereby the annular flange 7 formed on the end face of the tapered roller 5 and the inner and outer rings 1, 3. , 9 (the roller guide projecting on both sides of the raceway surface 1s) can be continuously supplied with the lubricant. As a result, it is possible to reduce wear and wear of the tapered roller 5 and the inner and outer rings 1 and 3, and to extend the life of the bearing.

  Furthermore, according to this modification, the depth k of the relief portion 10 is set in the range of 10% to 30% of the width dimension H of the annular portions 2 and 4, thereby increasing the strength of the cage 11 as a whole. It becomes possible to keep constant, and as a result, the rotational performance of the bearing can be kept constant over a long period of time. In particular, the bearings that support the rotating shafts (for example, axles) provided on high-speed railway vehicles such as the Shinkansen and the output shafts of the main motors are subjected to high loads under high-speed rotation. Although the container 11 is required to have a high strength, the retainer 11 of the present modification can sufficiently cope with this.

Here, the effect of the cage 11 of the present modification as described above will be demonstrated using a stress generation model.
FIG. 3 (a) shows a cage model in which the pocket 8 (FIG. 2) does not have the relief portion 10, and the annular portions 2, 4 have a thickness dimension T = 8 and a width dimension H = 10. The column portion 6 is set to have a length dimension E = 15 and a column length L = 20 to the center of the annular portion. Then, a load F = 50 (for example, 50 Newton) is applied to the column portion 6 to generate a moment M in the cage model. At this time, it is assumed that a uniform distributed load W acts on the column portion 6.

From the material mechanical relationship under such conditions, the stress σ ₀ (reference stress) generated in the column portion 6 is calculated as the following equation (1) from the following equations (2) and (3).
σ ₀ = M / Z (Z: section modulus) (1)
^{M = W · L 2/2} ... (2)
^{Z = T · H 2/6} ... (3)

FIG. 3 (b) shows a cage model having an existing relief portion 10a in the pocket 8 (FIG. 2). The relief portion 10a is formed in a portion adjacent to the end portion 6e of the column portion 6 at a single portion. It has an arc shape formed with only one curvature radius ρ. In this case, when the bending stress generated in the annular portions 2 and 4 is obtained from the material mechanical relationship, the tensile stress σmax generated at the four corners of each pocket 8 in consideration of the stress concentration is calculated as Equation (4). The
σmax = ασ ₀ (α: Stress concentration factor) (4)

Here, structural analysis (FEM analysis) based on the finite element method is performed on the cage model of FIG. 3B, and from the σmax obtained from the analysis result and the reference stress σ ₀ obtained from material mechanics. The stress concentration coefficient α is calculated as equation (5).
α = σmax / σ ₀ (5)

  FIG. 4 (a) shows the calculation result of the stress concentration coefficient α in the cage model of FIG. 3 (b). The radius of curvature of the relief portion 10a is ρ, the depth dimension is k, the annular portion 2 is shown. , 4 is H and ρ = k, the stress concentration coefficient α is an extreme value (α = 3.65 to 3.76, αmin = in the range of ρ / H = 0.1 to 0.3). It can be seen that 3.39) is taken.

  FIG. 3C shows a cage model of the present embodiment having an existing relief portion 10 in the pocket 8 (FIG. 2), where the width dimension of the relief portion 10 is 2n, ρ / H = 0. When the stress concentration coefficient α is calculated based on this, a calculation result as shown in FIG. 4B is obtained. According to this calculation result, n / ρ = 1.0 is the dimensions (single curvature radius ρ) indicating the minimum value (αmin = 3.39) of the stress concentration coefficient α in FIG. It can be seen that when n / ρ exceeds 1.0, the stress concentration coefficient α decreases, and the effect of reducing stress concentration is exhibited. In this case, since n / ρ = 2.0 or later takes a substantially constant extreme value, it is preferable to set the relief portion 10 so that n / ρ is 2.0 or more.

(a) is a longitudinal sectional view of a tapered roller bearing, (b) is a transverse sectional view of FIG. (a), and (c) is set to a minimum window angle in one embodiment of the present invention. Sectional drawing which expands and shows a part of bearing in which the cage for bearings was integrated, (d) is an embodiment of the present invention, in which the cage for bearings set to the maximum window angle is incorporated Sectional drawing which expands and shows a part of bearing, (e) is a figure which shows the structure of a window angle. (a) is a perspective view showing an overall configuration example of a bearing retainer according to a modification of the present invention, (b) is an enlarged view of a part of the retainer of FIG. (c) is the enlarged view which looked at some cages of the figure (a) from the inside, (d) is the figure which expands and shows the structure of an escape part. It is a figure which shows the generation | occurrence | production model of stress, (a) is a cage model without a relief part in a pocket, (b) is a cage model which has an existing relief part, (c) is this modification example. Cage model. It is a figure which shows the FEM analysis result of a stress concentration count, Comprising: (a) is the analysis result in the existing cage, (b) is the analysis result of the cage of this modification.

Explanation of symbols

2,4 torus
2s, 4s Inner circumferential surface 6 Column 6s Inner wall surface 8 Pocket θ Window angle

Claims (7)

A bearing retainer that revolves along the inside of the bearing together with the plurality of rolling elements while holding the plurality of rolling elements within the bearing rotatably,
At least one annular portion that is circumferentially continuous along the bearing interior;
A plurality of pillars extending from the annular part along the inside of the bearing, and arranged at predetermined intervals in the circumferential direction along the annular part;
A plurality of pockets that are partitioned by the inner peripheral surface of the annular portion and the inner wall surfaces of the plurality of column portions and rotatably hold the plurality of rolling elements one by one;
A bearing retainer characterized in that a window angle formed between inner wall surfaces of two pillar portions defining each pocket is set to 44 ° or more and 60 ° or less.   The bearing cage according to claim 1, wherein each pocket can rotatably hold a roller as a rolling element.   The bearing retainer according to claim 1 or 2, wherein the whole is formed of a resin material. Each pocket is provided with a relief portion formed by recessing a portion of the annular portion adjacent to the pillar portion by a predetermined depth,
The escape portion includes one flat surface formed flat across the annular portion, and two arc-shaped surfaces continuous at a predetermined curvature from both sides of the flat surface toward the annular portion and the column portion. The bearing retainer according to any one of 1 to 3, wherein   In a bearing in which a roller is applied as a rolling element, the relief portion is configured by setting the overall width dimension from two arcuate surfaces to one flat surface larger than the chamfer dimension formed on the end surface of the roller. The bearing retainer according to claim 4, wherein the bearing retainer is provided.   The bearing retainer according to claim 4 or 5, wherein the relief portion is configured with a depth dimension set in a range of 10% to 30% of a width dimension of the annular portion. The bearing retainer according to any one of claims 1 to 6, wherein the bearing retainer is applicable to a bearing that supports a rotating shaft provided in a railway vehicle.

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