JP3949319B2 - Roller bearing and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a roller bearing including a plurality of rollers and a method for manufacturing the roller bearing.
[0002]
[Prior art]
A general needle roller bearing will be described with reference to FIGS. 8 is a cross-sectional view of the needle roller bearing, FIG. 9 is a process diagram for explaining the production of the needle roller of FIG. 8, and FIG. 10 is based on the edge load of the needle roller of FIG. It is explanatory drawing with which it uses for description of a subject.
[0003]
In FIG. 8, 2 is an outer ring, 4 is a cage, and 6 is a needle roller.
[0004]
As shown in FIG. 9, such a needle roller 6 includes a shearing process in which a roller wire is matched to the length of the needle roller, a chamfering process by a chamfering barrel on the sheared surface, a curing process by heat, Manufactured by polishing and surface finishing.
[0005]
In such a needle roller 6, as shown in FIG. 10A, the bus is composed of a central bus 6 a and both end buses 6 b. The central bus 6a corresponds to the rolling surface of the needle roller 6 and is always a straight line along the axial direction even if it rolls. The boundaries between the two bus bars 6a and 6b that appear when the needle rollers 6 roll are the edge positions of the circumferential edges. Here, 6c is an edge formed by connecting edge positions in the circumferential direction. The direction of the edge 6c is not displaced in the axial direction, but is positioned on one line substantially perpendicular to the axial direction. Therefore, the rolling trace of the edge 6c of the needle roller 6 that appears on the inner peripheral surface of the outer ring 2 due to the rolling of the needle roller 6 is shown in FIG. As shown by, it has a shape that passes on a straight line 8 in a direction orthogonal to the axial direction. Therefore, although the rolling trace 10 by rolling of the needle roller 6 is formed in the outer ring | wheel 2, the rolling trace 10 as shown in FIG.10 (c) is formed by the above-mentioned passing aspect of the edge 6c. The In this case, since the load is concentrated on the edge 6c of the needle roller 6, the rolling trace 10a formed by the edge 6c is the rolling trace formed by the rolling surface excluding the edge 6c of the needle roller 6. It becomes deeper than 10b.
[0006]
[Problems to be solved by the invention]
Therefore, in such a needle roller bearing, the range in which the needle roller is in rolling contact with the inner peripheral surface of the outer ring 2 is constant, and the rolling trace 10a by the edge 6c of the needle roller 6 is in the constant range. As a result, the rolling trace 10a in which the load is concentrated progresses further in the depth direction. As a result, the rolling trace 10a starts as a starting point, and the outer ring 2 is quickly worn or peeled off. The damage could result in poor durability.
[0007]
In order to solve this type of problem, a crowning process is generally performed to relieve the contact stress on the rolling surface. Various types of crowning shapes have been proposed, one with a constant radius of curvature, so-called multi-stage crowning with a gradually decreasing radius of curvature toward the end, and logarithmic crowning with the crowning shape bus as a logarithm Etc. In the logarithmic crowning, the contact stress on the rolling surface becomes uniform and the concentration of the contact portion stress can be prevented with respect to various misalignments. However, as shown in FIG. The stress in the range becomes high, and fatigue damage occurs in the maximum load portion δ2.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problem, a roller bearing according to the present invention is a roller bearing including a plurality of rollers, and a boundary between a chamfered portion of an end face of at least one roller included in the plurality of rollers and a rolling surface. The edge is formed at the same time as the roller wire is sheared to the roller length , and when the roller wire is sheared to the roller length, an arbitrary process from immediately after the start of shearing to just before the end of shearing. Thus, by arbitrarily changing the magnitude of the shear load, the shape of the peripheral edge of the roller shearing surface is appropriately changed in the circumferential direction, whereby the edge position is displaced in the axial direction in at least a part of the circumferential direction of the roller. It is characterized in that there.
[0010]
Preferably, crowning is applied to the end of the rolling surface of the roller including an edge that is displaced in the axial direction.
[0011]
The significance of the axial displacement of the rolling trajectory here includes not only the entire displacement but also the partial displacement, and the displacement. The degree of is not questioned.
[0012]
The method of manufacturing a roller bearing according to the present invention includes a shearing process for shearing a roller wire in accordance with the axial length of the roller, and a chamfering process for chamfering the end of the sheared roller wire. At least, the shear load applied from the substantially vertical direction to the roller wire rod in the shearing process is arbitrarily changed in the arbitrary process from immediately after the start of shearing to just before the end of shearing. Thus, an edge that becomes a boundary between the chamfered portion of the roller and the rolling surface is displaced in at least a part of the circumferential direction of the roller .
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, details of the present invention will be described in detail with reference to the drawings.
[0015]
1 and 2 relate to the present embodiment, FIG. 1 is a sectional view of the needle roller bearing, and FIG. 2 is a diagram for explaining an edge load of the needle roller bearing of FIG. In these drawings, portions corresponding to those in FIGS. 8 and 11 are denoted by the same reference numerals.
[0016]
In the roller bearing of the embodiment, the rolling locus of the edge 6c accompanying the rolling of the needle roller 6 is displaced with respect to the axial direction. In order to have such a rolling locus, specifically, a part or the whole of the edge 6c on one end side or both end sides of the needle roller 6 is displaced with respect to the axial direction.
[0017]
Such displacement of the edge 6c will be described with reference to FIG. 2 (a) corresponds to FIG. 10 (a), FIG. 2 (b) corresponds to FIG. 10 (b), and FIG. 2 (c) corresponds to FIG. 10 (c). As shown in FIG. 2A, the shape of the bus bar of the needle roller 6 according to the embodiment is composed of a center bus 6a and both end buses 6b. An edge 6c shown by connecting each edge position in the circumferential direction is inclined and displaced with respect to the axial direction. The rolling trajectory of the displaced edge 6c becomes curved trajectories 12a to 12d that change with a constant amplitude W in the axial direction, as shown in FIG. However, the trajectories 12a and 12b are trajectories during different rolling of the upper edge 6c in the axial direction, and the trajectories 12c and 12d are trajectories during different rolling of the lower edge 6c in the axial direction. In addition, A has shown the end surface part of the needle roller 6, and B has shown the chamfering part of the needle roller 6. FIG.
[0018]
Therefore, since the edge 6c of the needle roller 6 has the locus as described above, the rolling trace 10 by the needle roller 6 on the outer ring 2 is as shown in FIG. That is, since the rolling trajectory of the upper and lower edges 6 c does not repeatedly pass through the same place, the rolling trace 10 a by the upper and lower edges 6 c is more than the rolling trace 10 b by the rolling surface of the needle roller 6. It is not necessary to deepen, and conversely, wear is reduced due to the small number of rolling repetitions, so that the outer ring 2 is cracked and broken due to rolling traces by the upper and lower edges 6c. This can be prevented.
[0019]
In the case of the edge 6c described above, the line connecting all of the edge positions is a linear shape inclined with respect to the axial direction, but is not limited to such a linear shape, and at least a part of the edge positions is included. As long as the edge position of the edge 6c is displaced in the axial direction, for example, as shown in FIG. 3, it may be a curved line, a wavy line, or the like respectively indicated by a dotted line or a virtual line. It is preferably displaced entirely in the axial direction and may be partially displaced.
[0020]
The needle roller 6 having the edge 6c described above may be manufactured as shown in FIG. 9, but in such manufacture, the cost of forming the edge 6c is high, and the manufacture thereof is not always easy. Therefore, for example, as described with reference to FIG. That is, the manufacturing method of the embodiment includes at least a shearing step of shearing the roller wire in accordance with the axial length of the roller and a chamfering step of chamfering the end of the sheared roller wire. And an edge where the rolling trajectory is displaced in the axial direction is formed on the shear surface side by a change in the shear load applied to the roller wire during the shearing process. The significance of the roller wire here is not intended to limit its diameter. Any needle-like, rod-like, or other similar diameters may be used as long as it has a diameter adapted to each of the similar rollers. In other words, the rod-like or columnar shape is included in the roller wire. .
[0021]
Specifically, as shown in FIG. 4A, the shearing blade 14 is arranged so as to be guided in the direction of the arrow by a guide mechanism (not shown), and the roller wire 16 is connected by a holding mechanism and a guide mechanism (not shown). The roller can be guided to a position where it can be sheared by the shearing blade 14, and the roller wire 16 is sheared by the shearing blade 14 according to the length of the needle roller 6. At this time, as shown in FIG. 4B, the shear load applied to the roller wire 16 from the shear blade 14 is the maximum load P1 immediately after the start of shearing at the upper end of the roller wire 16, and the roller wire 16 During the shearing, for example, the load P2 at the time of half-shearing is medium, and the load P3 at the time when the roller wire 16 is just before the end of shearing becomes the minimum. Since the load on the roller wire 16 changes in the shearing process in this way, as shown in FIGS. 4C and 4D, the shape of the peripheral edge 18a to which the load P1 is applied at the peripheral edge of the shearing surface 18, and the load The shape of the peripheral edge 18b to which P2 is applied differs from the shape of the peripheral edge 18c to which the load P3 is applied. As a result, when the shear blade 14 is sheared to the length of the needle roller 6, the edge 6c constituted by the peripheral edges 18a to 18c is displaced in the axial direction as shown in FIGS. 4 (e) and 4 (f). The needle roller 6 is obtained. Since the rolling locus of the edge 6c is also displaced from the axial direction in such a needle roller 6, it becomes the edge 6c having the same effect as described above. Then, after this shearing step, a chamfering process is performed for removing the burrs existing on the peripheral edge 18c, that is, chamfering. In other words, this manufacturing method requires a shearing process in which the roller wire 16 is matched to the length of the needle roller and a chamfering process for the sheared surface 18, but a curing process by heat is required, but the polishing process is omitted. Making it possible makes it cheaper. Moreover, since the edge 6c also merely shears the roller wire with the shearing blade 14, it is easy to form the edge 6c.
[0022]
1 can be manufactured as described with reference to FIGS. 5 and 6. FIG. Hereinafter, this manufacturing method will be described with reference to FIGS. FIG. 5 shows a pair of left and right dies 20a and 20b, a roller wire 16 formed by both dies 20a and 20b, and a roller 6 shown in the direction of the arrow. FIG. One mold 20a (20b) is shown. In this manufacturing method, a pair of left and right molds 20a and 20b are prepared. Both molds 20 a and 20 b have a recess 22. These recesses 22 match the end shape of the needle roller 6 shown in FIG. Specifically, the shape of the bottom wall 22a of the recess 22 matches the outer shape of the end surface portion A of the needle roller 6 shown in FIG. 2, and the shape of the inner peripheral side wall 22b of the recess 22 is a needle. It matches the outer shape of the chamfered portion B of the roller 6. Then, both ends of the roller wire 16 are connected to a pair of left and right molds 20a. In the state inserted into the respective recesses 20b, both molds 20a, 20b are clamped from the direction of the arrow, and end portions similar to both ends of the needle roller 6 shown in FIG. A and chamfered portion B are plastically deformed and molded. As a result, a roller 6 having an edge 6c whose circumferential rolling locus is displaced in the axial direction as shown in FIG. 3 is formed.
[0023]
The present invention is not limited to the above-described embodiment, and can be similarly applied to roller bearings in general.
[0024]
In the present invention, the edge 6c displaced in the axial direction is not limited to both ends of the needle roller 6 as in the above-described embodiment, and the edge 6c on one end is displaced in the axial direction. Including cases.
[0025]
Further, in the present invention, the roller bearing need not be limited to a bearing having a needle roller, but includes a roller having a needle shape, a rod shape, or the like. In particular, it is not limited to rollers in which the entire bus bar portion of the rolling surface, which is the outer peripheral surface of the roller, is linear in the axial direction, and there is a step in any part such as in the middle of the bus bar portion of the rolling surface. Even if it is attached or has a curved shape, these shapes of rollers are included.
[0026]
Furthermore, in the present invention, the roller used for the roller bearing need not be limited to a solid roller, and includes a roller having a hollow shape or a cylindrical roller.
[0027]
Furthermore, in the embodiment, the needle roller bearing has an outer ring and has no inner ring, and the rolling surface on which the roller rolls is only the inner circumferential surface of the outer ring. In the case where an inner ring is provided as the roller bearing, the rolling surface on which the roller rolls may be the outer peripheral surface of the inner ring.
[0028]
Further, instead of a normal outer ring, the inner peripheral surface of another component may be a raceway surface.
[0029]
Further, in the present invention, in the roller bearing in which the rolling locus of the edge of the rolling surface end of the roller with respect to the raceway is displaced in the axial direction, an edge that is displaced in the axial direction is provided at the rolling surface end of the roller 6. Including it may be crowned. When such crowning is applied, even if the crowning is operated at a constant inclination θ as shown in FIG. 7, the maximum load portion always changes as δ3 and δ4, resulting in fatigue damage. It is possible to obtain a roller bearing that is difficult to perform.
[0030]
【The invention's effect】
As described above, according to the roller bearing of the present invention , even if the rolling range of the roller with respect to the rolling surface is concentrated in a certain range, the roller bearing is formed on the rolling surface. As a result of the rolling traces no longer concentrating on the range, the inner race or the outer ring where the rollers roll from the rolling trace as a starting point may cause early wear or delamination, resulting in final damage. Is eliminated and the durability is improved.
[0031]
In this case, the structure is simple in the case where at least a part of the edge positions in the circumferential direction of the roller is displaced in the axial direction and the rolling locus of the edge is displaced in the axial direction. The production cost is also low.
[0032]
According to the bearing manufacturing method of the roller according to the present invention, only the present invention-specific edge shearing wire for roller and can be easily formed, bother, as a manufacturing method of a roller bearing does not require a dedicated process It's cheap.
[Brief description of the drawings]
1 is a cross-sectional view of a needle roller bearing according to an embodiment of the present invention. FIG. 2 is a diagram for explaining an edge load of the needle roller bearing of FIG. 1. FIG. FIG. 4 is a diagram for explaining a method for manufacturing the needle roller bearing of FIG. 1. FIG. 5 is a diagram for explaining another method for manufacturing the needle roller bearing of FIG. FIG. 6 is a perspective view of the mold shown in FIG. 5. FIG. 7 is a cross-sectional view of the main part of the needle roller bearing according to another embodiment of the present invention. Fig. 8 (a) is a side view of the roller, and Fig. 8 (b) is a view showing a main portion of the roller and a main portion of the outer ring. Fig. 8 is a cross-sectional view of a conventional needle roller bearing. FIG. 10 is a diagram for explaining a conventional method for manufacturing a needle roller bearing. FIG. 10 is a diagram for explaining a problem due to an edge load of the needle roller bearing of FIG. 8. FIG. 11 is a diagram for explaining a conventional problem. Sectional view of a main portion of the shaped roller bearings EXPLANATION OF REFERENCE NUMERALS
2 Outer ring 4 Cage 6 Needle roller 6c Edge

Claims (3)

In roller bearings with multiple rollers,
The edge that becomes the boundary between the chamfered portion of the end face of at least one roller included in the plurality of rollers and the rolling surface is formed simultaneously with shearing the roller wire to the roller length , When shearing the wire to the roller length, the peripheral shape of the roller shearing surface is appropriately changed in the circumferential direction by arbitrarily changing the size of the shear load in an arbitrary process from immediately after the start of shearing to just before the end of shearing. A roller bearing, wherein the edge position is displaced in the axial direction in at least a part of the circumferential direction of the roller. The roller bearing according to claim 1,
A roller bearing characterized in that crowning is applied to an end portion of the rolling surface of the roller including an edge that is displaced in the axial direction. A shearing process for shearing the roller wire in accordance with the axial length of the roller;
And at least a chamfering step for chamfering the end of the sheared roller wire,
By arbitrarily changing the magnitude of the shear load in an arbitrary process from immediately after the start of shearing to just before the end of shearing, the shear load applied from the substantially vertical direction to the roller wire rod in the process of shearing, A method of manufacturing a roller bearing, characterized in that an edge serving as a boundary between a chamfered portion and a rolling surface is displaced in at least a part of a circumferential direction of the roller.

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