Cage for roller bearing and roller bearing

Abstract

To prevent edge contact of a roller even when the roller held in a pocket is skewed.SOLUTION: A pillar part of a holder for a roller bearing comprises: a pocket surface 22 formed in a central region of the pillar part in an axial direction and facing the pocket; a first roller guide surface 23 that is formed in one region and the other region in the axial direction of the pillar part, protrudes toward the pocket with respect to the pocket surface 22, and guides a roller; a recessed part 25 that is formed at both end parts of the pillar part in the axial direction and retreats from the pocket with respect to the pocket surface 22; and a second roller guide surface 24 that is provided between the first roller guide surface 23 and the recessed part 25 in both end regions of the pillar part in the axial direction, protrudes toward the pocket with respect to the pocket surface 22 and retreats from the pocket from the first roller guide surface 23.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a roller bearing cage that aligns a plurality of rollers. [Background technology]

[0002] A conventional roller bearing cage having a ring portion, a column portion, and a pocket in which rollers are arranged is described in JP-A-8-312650 (Patent Document 1). In Patent Document 1, in an outer diameter guide type cage, a surface on the outer diameter side of the column portion is provided that is recessed below the outer diameter surface of the ring portion, and outer diameter claws are formed on this surface, and in an inner diameter guide type cage, a surface on the inner diameter side of the column portion is provided that is recessed below the inner diameter surface of the ring portion, and inner diameter claws are formed on this surface, preventing the outer diameter claws and inner diameter claws that hold the needle rollers from breaking the oil film.

[0003] In Patent Document 1, the circumferential dimension of the pocket is large in the axial center and small at both axial ends, so even though both ends of the needle roller are constantly in contact with the column portion, the lubricating oil is not sufficiently supplied to the contact points, and there is a concern that the oil film will run out. To address this issue, a technology described in JP 2001-041250 A (Patent Document 2) is known.

[0004] In Patent Document 2, both ends of the roller are crowned so that they are tapered, and oil grooves are provided at both axial ends of the pocket to prevent contact between both ends of the roller and both ends of the column portion.

[0005] In addition, in JP 2009-079674 A (Patent Document 3), the roller stop projection is made to have a rounded shape, which prevents the roller stop projection from having a sharp edge and thus prevents edge contact. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 8-312650 [Patent Document 2] JP 2001-041250 A [Patent Document 3] JP 2009-079674 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the above-mentioned conventional roller bearing cages have the following problems. That is, when pocket surfaces facing pockets are formed at both end portions and the central region of the bar portion, and a roller guideway surface is formed at both end regions of the bar portion near the center, as in the cage of Patent Document 1, the boundary between the pocket surfaces at both end portions and the roller guideway surface becomes an upright ridge like an edge. When the rollers are tilted (a phenomenon in which both ends lag and lead in the circumferential direction of the cage), the edge of the boundary mentioned above comes into edge contact with the rollers, and the oil film is broken.

[0008] In view of the above-mentioned circumstances, an object of the present invention is to provide a technique for eliminating edge contact when rollers are skewed. [Means for solving the problem]

[0009] For this purpose, the cage for a roller bearing according to the present invention comprises a pair of opposing ring portions, a plurality of pillar portions extending in the axial direction of the ring portions to connect the ring portions, and a pocket which is a space defined between adjacent pillar portions in the circumferential direction and by the pair of ring portions and in which rollers are disposed. The pillar portions have a pocket surface formed in an axial central region of the pillar portion and facing the pocket, first roller guide surfaces formed in one and the other axial regions of the pillar portion, respectively, which protrude toward the pocket beyond the pocket surface and guide the rollers, recessed portions formed on both axial end portions of the pillar portion, respectively, and which are recessed from the pocket beyond the pocket surface, and second roller guide surfaces provided in both axial end regions of the pillar portion between the first roller guide surface and the recessed portions, which protrude toward the pocket beyond the pocket surface and are recessed from the pocket beyond the first roller guide surfaces.

[0010] According to the present invention, when the rollers skew, the second roller guideway guides the rollers instead of the first roller guideway, so that the axial outer edge of the first roller guideway does not come into contact with the rollers, preventing the oil film from running out on the roller surfaces. In addition, the second roller guideway makes the roller skew angle smaller than before.

[0011] In one aspect of the present invention, the pillar portion further has an inclined surface formed between the first roller guideway and the second roller guideway and connected to these roller guideways. According to this aspect, since there is no edge between the first roller guideway and the second roller guideway, even if the roller is skewed and abuts against the inclined surface, the oil film on the roller surface is prevented from being cut off. The inclined surface may be included in the second roller guideway. Alternatively, it may be a third roller guideway disposed between the first roller guideway and the second roller guideway, and for example, the first roller guideway and the second roller guideway are surfaces parallel to the axis, and the third roller guideway is an inclined surface not parallel to the axis.

[0012] In a preferred aspect of the present invention, the surface of the recessed portion and the second roller guide surface are adjacent, the boundary between these surfaces forms a ridgeline, and the ridgeline has an ridge angle in the range of 100° to 180°. According to this aspect, the boundary line has an obtuse angle and no edge is formed at the boundary line, so that even if the rollers are skewed and come into contact with the boundary line, oil film breakdown on the roller surfaces is prevented.

[0013] The roller bearing cage of the present invention may further have a roller stop projection that restricts radial movement of the rollers. In a further preferred aspect of the present invention, the pillar portion further has a roller stop projection that projects toward the pocket, the roller stop projection including a first projection portion disposed at the same axial position as the first roller guideway surface and a second projection portion disposed at the same axial position as the second roller guideway surface, and a first projection amount of the first projection portion that projects circumferentially from the first roller guideway surface is greater than a second projection amount of the second projection portion that projects circumferentially from the second roller guideway surface. According to this aspect, the edge of the roller stop projection is less likely to come into contact with the rollers, reducing the concern that the rollers will come into edge contact with the roller stop projection and the rollers will break the oil film when the rollers skew.

[0014] A roller bearing of the present invention comprises the roller bearing cage described above, and rollers disposed in the pockets of the roller bearing cage. Effect of the Invention

[0015] As described above, according to the present invention, when the rollers are skewed, the edges of the rollers and the column portions are prevented from coming into contact with each other, thereby eliminating the problem of oil film breakdown on the roller surfaces. [Brief description of the drawings]

[0016] [Figure 1] 1 is an overall perspective view showing one embodiment of the present invention; [Diagram 2] FIG. [Diagram 3] FIG. 4 is an enlarged view showing one pillar portion from the embodiment. [Figure 4] FIG. 4 is an enlarged view showing one pillar portion from the embodiment. [Diagram 5] FIG. 4 is a cross-sectional view showing one pocket taken out from the embodiment. [Figure 6A] 4 is an enlarged view showing a cross-sectional shape of a first roller guide surface according to the embodiment. FIG. [Figure 6B] 4 is an enlarged view showing a cross-sectional shape of a first roller guide surface according to the embodiment. FIG. [Figure 7] 1 is an enlarged image showing the same embodiment. [Figure 8] FIG. 11 is a cross-sectional view showing a pocket of a conventional example. [Figure 9] FIG. 13 is a diagram showing a pocket surface and a roller guide surface of a cage in a conventional example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is an overall perspective view showing a roller bearing cage according to one embodiment of the present invention. FIG. 2 is an enlarged perspective view showing the same embodiment. The roller bearing cage 10 includes a pair of ring portions 11, 11, a plurality of column portions 21 extending in the axial direction of the ring portions 11 and connecting the ring portions 11, 11, and a pocket 31 which is a void defined between the column portions 21, 21 adjacent in the circumferential direction and by the pair of ring portions 11, 11. In the following description, the axial direction of the roller bearing cage 10 (ring portions 11) is simply referred to as the axial direction, the circumferential direction of the roller bearing cage 10 (ring portions 11) is simply referred to as the circumferential direction, and the radial direction of the roller bearing cage 10 (ring portions 11) is simply referred to as the radial direction.

[0018] The pillar portion 21 faces the pockets 31 on both circumferential side surfaces of the roller bearing cage 10. On these side surfaces of the pillar portion 21, a pocket surface 22, a first roller guide surface 23, a second roller guide surface 24, and a recessed portion 25 are formed. The recessed portion 25 introduces lubricating oil into the pockets 31. A roller (not shown) is disposed in each pocket 31. The rollers are, for example, needle rollers. The circumferential dimension of the pockets 31 is greater than the diameter of the rollers.

[0019] FIG. 3 is an enlarged view of one column portion taken out from the embodiment, showing the state seen from the radial outside of the roller bearing cage 10. FIG. 4 is an enlarged view of one column portion taken out from the embodiment, showing the state seen in the circumferential direction of the roller bearing cage 10. The pocket surface 22 is a plane that retreats from the pocket 31, while the first roller guide surface 23 is a plane that protrudes toward the pocket 31. In other words, the first roller guide surface 23 is a surface that protrudes toward the pocket 31 more than the pocket surface 22 as shown in FIG. 3, and contacts the surface of a roller (not shown) to guide it in the circumferential direction. The roller (not shown) is held in a position parallel to the axis by simultaneously contacting the first roller guide surface 23 provided on one side of the axial direction of the column portion 21 and the first roller guide surface 23 provided on the other side of the axial direction of the column portion 21. The pocket surface 22 is always separated from the roller and does not contact it. This allows lubricating oil to flow into the gap between the pocket surface 22 and the roller.

[0020] 3, the recessed portion 25 is a recess that is recessed from the pocket 31 further than the first roller guideway surface 23 and the pocket surface 22. That is, with respect to the circumferential dimension of the pillar portion 21, the dimension Cs at the recessed portion 25 is the smallest, and the dimension Ca at the first roller guideway surface 23 is the largest.

[0021] 3, the pocket surface 22 is disposed in the axial central region of the pillar portion 21. The first roller guide surfaces 23 are disposed in one axial region and the other axial region of the pillar portion 21. The second roller guide surfaces 24 are disposed axially outward of one of the first roller guide surfaces 23 and the other of the first roller guide surfaces 23. The recessed portions 25 are provided at the joining points between the ends of the pillar portion 21 and the ring portion 11, specifically at both ends of the pillar portion 21.

[0022] The second roller guide surface 24 is recessed from the pocket 31 more than the first roller guide surface 23, but protrudes toward the pocket 31 more than the pocket surface 22. In other words, the circumferential dimension of the pillar portion 21 is such that the dimension Cb at the second roller guide surface 24 is smaller than the dimension Ca and is larger than the circumferential dimension Cd at the pocket surface 22 (Cs <Cd<Cb<Ca)。

[0023] First roller guide surface 23 and second roller guide surface 24 of the present invention are flat surfaces facing pocket 31. An axial dimension Wa of first roller guide surface 23 is larger than an axial dimension Wb of second roller guide surface 24 (Wa>Wb).

[0024] 5 is a cross-sectional view showing how the second roller guide surface 24 guides the roller, showing the state when the pocket is viewed in the radial direction. When the roller 40 is skewed, the second roller guide surface 24 contacts and guides the roller 40, and at this time, the axial outer edge 23f of the first roller guide surface 23 does not contact the roller 40. According to this embodiment, the second roller guide surface 24 reduces the skew angle of the roller 40. In addition, the second roller guide surface 24 prevents the roller 40 from contacting the axial outer edge 23f, or even if the roller 40 contacts the axial outer edge 23f, the load acting from the roller 40 on the axial outer edge 23f is reduced.

[0025] 5, in this embodiment, the value of the step formed at the boundary between the first roller guide surface 23 and the second roller guide surface 24 is represented by the dimension Cf. The dimension Cf is 0.01 mm or less (Cf≦0.01). In this way, the connection between the second roller guide surface 24 and the second roller guide surface 24 becomes less noticeable, making it difficult for an edge to be generated. This prevents the roller 40 from contacting the edge even if the roller 40 is skewed as shown by the two-dot chain line. The dimensional relationship between the dimension Cf and the dimensions Ca and Cb (FIG. 3) is as follows: [Formula 1] Cf=(Ca+Cb) / 2

[0026] 6A and 6B are enlarged views showing the gap between the first roller guide surface 23 and the second roller guide surface 24, as viewed in the radial direction. FIG. 7 is an image showing this embodiment, as viewed from the oblique outer diameter side. In this embodiment, as shown in FIG. 6A, the first roller guide surface 23 and the second roller guide surface 24 are flat or curved surfaces parallel to the axis, and an inclined surface 26 is formed between the first roller guide surface 23 and the second roller guide surface 24. The inclined surface 26 is not parallel to the axis, and smoothly connects to the first roller guide surface 23 and the second roller guide surface 24. Alternatively, as a modified example not shown, the inclined surface 26 may be smoothly connected to the first roller guide surface 23 and / or the second roller guide surface 24 via a curved surface.

[0027] 6B shows a modified example of this embodiment, in which the second roller guide surface 24 of the modified example is an inclined surface that is not parallel to the axis. According to this embodiment and the modified example, the ridge angle at the axial outer edge 23f is made obtuse, and no step is formed at the boundary between the first roller guide surface 23 and the second roller guide surface 24. Therefore, no edge is formed at the axial outer edge 23f, and even if the roller 40 is skewed and contacts the axial outer edge 23f, the oil film on the surface of the roller 40 is prevented from running out. Alternatively, as a modified example not shown, the axial outer edge 23f may be made a curved surface, and the second roller guide surface 24, which is an inclined surface, may be smoothly connected to the first roller guide surface 23 via the curved surface.

[0028] 5 indicates the boundary between the second roller guide surface 24 and the reduced thickness portion 25, and shows the state when viewed in the radial direction. The surface of the reduced thickness portion 25 and the second roller guide surface 24 are adjacent to each other, and the boundary line 27 between these surfaces forms a ridge line. This ridge line extends in the radial direction. In a cross section perpendicular to this ridge line, the ridge angle R formed by the surface of the reduced thickness portion 25 and the second roller guide surface 24 is an obtuse angle in the range of 100° or more and 180° or less (preferably less than 180°). According to this embodiment, since the ridge angle at the boundary line 27 is an obtuse angle, no edge is formed, and even if the roller 40 is skewed and contacts the boundary line 27, the oil film on the surface of the roller 40 is prevented from running out.

[0029] 3 and 4, a roller stop projection 32 is provided in the axial end region of column portion 21. Roller stop projection 32 is arranged on the outer diameter side of first roller guide surface 23 and second roller guide surface 24, and restricts the rollers from moving toward the outer diameter side. Roller stop projection 32 is arranged on the radially outer side of column portion 21, protrudes toward pocket 31, and faces roller stop projection 32 that is similarly provided on adjacent column portion 21. The distance between such roller stop projections 32, 32 is smaller than the diameter of the roller, so that the roller is prevented from falling out of pocket 31.

[0030] The axial position of the roller stop projection 32 includes a first projection portion 33 arranged at the same axial position as the axial position of the first roller guideway surface 23, and a second projection portion 34 arranged at the same axial position as the axial position of the second roller guideway surface 24. A first projection amount Pa of the first projection portion 33 protruding in the circumferential direction from the first roller guideway surface 23 is larger than a second projection amount Pb of the second projection portion 34 protruding in the circumferential direction from the second roller guideway surface 24. According to this embodiment, even if the roller stop projection 32 comes into contact with the roller in a roller skew phenomenon, the contact area becomes large, so that oil film breakdown on the roller surface is avoided.

[0031] In order to facilitate understanding of this embodiment, a conventional example will be described. Figures 8 and 9 are views showing a pocket of a conventional example, and Figure 8 is a cross-sectional view showing a state in which the bar portion is cut along a plane indicated by VIII-VIII in Figure 9 (a plane perpendicular to the diameter of the cage) and the cut surface is viewed in the radial direction. Figure 9 is an enlarged view showing the pocket surface and the roller guide surface of the conventional example, showing a state in which the bar portion 1 is taken out and viewed in the circumferential direction of the cage. Referring to Figure 8, the roller guide surface 123 of the conventional example was provided at both end regions in the axial direction of the bar portion 121. The axial outer edge 123f of the roller guide surface 123 was an edge, forming an upright ridgeline. For this reason, when the roller 40 was skewed and contacted the axial outer edge 123f, the oil film on the surface of the roller 40 was broken.

[0032] The reason for this is that burnishing is performed on excess material 133, which is a part of the side surface of column portion 121, and this burnishing forms outer claws 132 on the outer diameter side of column portion 121. Burnishing refers to a process in which a burnishing tool (not shown) is moved radially and pressed against the circumferential side surface of column portion 121 (a surface (surface of excess material 133) continuing to pocket surface 122), plastically deforming a part of excess material 133 on the circumferential side surface of column portion 121 so as to cut it radially, and causing outer claws 132 to protrude toward the pocket. In the conventional example, when such burnishing is performed, when excess material 133 is cut to form roller guide surface 123, a sharp protruding edge is formed on axial outer edge 123f of roller guide surface 123.

[0033] In this embodiment, since the second roller guide surface 24 is formed axially outward of the first roller guide surface 23, the edge 123f as in the conventional example is not generated, and the axially outer edge 23f does not become an edge.

[0034] In this embodiment, a roller stop projection 38 is provided on the radially inner side of the column portion 21. The roller stop projections 38 are arranged at two locations spaced apart in the axial central region of the column portion 21, and protrude further toward the pocket 31 than the pocket surface 22. The roller stop projections 38 restrict the rollers from moving toward the inner diameter side. The roller stop projections 38 face another roller stop projection 38 that is similarly provided on the adjacent column portion 21. The distance between these roller stop projections 38, 38 is smaller than the diameter of the roller, so the roller is prevented from falling out of the pocket 31.

[0035] The roller stop projection 38 is formed by burnishing the circumferential side surface of the column portion 21 from the outer diameter side to the inner diameter side. The pocket surface 39 after being burnished is located on the outer diameter side of the roller stop projection 38 and protrudes toward the pocket 31 further than the pocket surface 22, but is recessed from the pocket 31 further than the second roller guide surface 24.

[0036] In this embodiment, the connection regions 28, 28 between the axial center region and the axial end regions are obliquely shaped so that the axial center region of the column portion 21 is located radially inward relative to both axial ends as shown in Fig. 4. These connection regions 28, 28 are formed by pressing.

[0037] It should be noted here that the connection regions 28, 28 are formed by pressing the widthwise center region and the widthwise end region of the strip steel alternately during the rolling process of the strip steel. The column portion 21 and the pocket 31 are formed simultaneously by punching the strip steel with a punch having the same profile as the pocket 31. The strip steel is cut to an appropriate length, rolled, and both ends are joined by welding.

[0038] As shown in FIG. 4, the outer diameter surface of the column portion 21 is recessed toward the inner diameter side from the outer diameter surface 12 of the ring portion 11. Specifically, the outer diameter surface 35 of the axial end of the column portion 21 is made to be the same surface (flat surface or cylindrical surface) as the outer diameter surface 12. In addition, the outer diameter surface 36 located axially inward from the outer diameter surface 35 and axially outward from the connection region 28 is made to be a flat surface recessed toward the inner diameter side from the outer diameter surface 35. This allows lubricating oil to flow between the outer diameter surface of the roller bearing retainer 10 and the roller stop projections 32, lubricating the roller stop projections 32. This configuration is particularly useful when the roller bearing retainer 10 is used as an outer diameter guide. In addition, the outer diameter surface 37 of the axial center region of the column portion 21 is made to be a flat surface recessed toward the inner diameter side from the outer diameter surface 35. The roller bearing retainer 10 of this embodiment is a V-shaped retainer.

[0039] Although the embodiment of the present invention has been described above with reference to the drawings, the present invention is not limited to the illustrated embodiment. Various modifications and variations can be made to the illustrated embodiment within the same scope as the present invention or within an equivalent scope. [Explanation of symbols]

[0040] 10 roller bearing retainer, 11 ring portion, 21 column portion, 22 pocket surface, 23 first roller guide surface, 24 second roller guide surface, 23f: an axially outer edge of the first roller guide surface; 25: a recessed portion; 26 Slope, 27 Boundary, 28 Connection area, 31 pocket; 32, 38 roller stopper protrusion; 33 first protrusion portion; 34 second protrusion portion, 40 roller, R edge angle, 123 roller guide surface, 123f edge, 132 outer jaw 122 Pocket surface, 133 excess material.

Claims

1. a pair of ring portions; a plurality of pillar portions extending in an axial direction of the ring portions and connecting the ring portions; and pockets in which rollers are disposed, the pockets being voids defined between adjacent pillar portions in a circumferential direction and by the pair of ring portions, The column portion is a pocket surface formed in an axial center region of the pillar portion and facing the pocket; a first roller guide surface that is formed in one axial region and the other axial region of the column portion, protrudes toward the pocket beyond the pocket surface, and guides the roller; a recessed portion formed at each of both axial ends of the column portion and recessed from the pocket relative to the pocket surface; a second roller guide surface provided between the first roller guide surface and the recessed portion in each of both axial end regions of the column portion, the second roller guide surface protruding toward the pocket beyond the pocket surface and receding from the pocket beyond the first roller guide surface; a roller bearing retainer having an inclined surface formed between the first roller guideway and the second roller guideway and connecting with these roller guideways.

2. 2. The roller bearing cage according to claim 1, wherein a surface of the recessed portion and the second roller guide surface are adjacent to each other, the boundary between these surfaces forms a ridgeline, and the ridgeline has an ridge angle in the range of 100° or more and 180° or less.

3. The pillar portion further has a roller stop projection protruding toward the pocket, the roller stop projection includes a first projection portion disposed at the same axial position as the axial position of the first roller guideway surface, and a second projection portion disposed at the same axial position as the axial position of the second roller guideway surface, 3. A retainer for a roller bearing as described in claim 1 or 2, wherein a first protrusion amount of the first protrusion portion protruding circumferentially from the first roller guide surface is greater than a second protrusion amount of the second protrusion portion protruding circumferentially from the second roller guide surface.

4. A roller bearing cage according to any one of claims 1 to 3, A roller bearing comprising a roller disposed in the pocket.

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