Roller fall-off prevention tool and bearing with roller fall-off prevention tool

Abstract

A roller fall-off prevention tool (1) is applied to a bearing (11) in a form in which a roller (13) falls on an inner diameter side of a cage (12). On the outer periphery of both end portions in an axial direction, a tapered portion (2) is formed, in which an incident angle with respect to the bearing (11) is less than 45°. The outer periphery of an intermediate portion in the axial direction is a straight portion (3) forming a cylindrical surface parallel to the axis. From both end surfaces in the axial direction, four or more slits (4) are alternately formed at equal intervals in a circumferential direction. When the tool is mounted on the bearing (11), the straight portion (3) is brought into contact with the roller (13) by being fitted into the inner side of the inscribed circle of the roller (13) from the small-diameter end of the tapered portion (2). When the tool is removed from the bearing (11), the shaft or the inner ring is abutted against a ridge (5) extending in the axial direction on the inner diameter surface.

Description

Roller fall-off prevention device and bearing with roller fall-off prevention device

[0001] The present invention relates to a roller dropout prevention jig for roller bearings that rotatably support components that are subjected to large centrifugal forces due to revolution, such as planetary gears in automatic transmissions for automobiles and the large ends of connecting rods in internal combustion engines.

[0002] Cage-and-roller bearings, a typical example of needle roller bearings, do not have inner or outer rings, and typically have a cage structure that prevents the rollers from falling out to the outer or inner diameter side. However, in bearings with a large number of rollers, the column width between the cage pockets cannot be ensured, making it impossible to design a structure that prevents the rollers from falling out to the inner diameter side. Furthermore, even in shell-type needle roller bearings without an inner ring, some do not have a structure that prevents the rollers from falling out to the inner diameter side in order to avoid increasing the load capacity and complicating the structure.

[0003] For bearings that do not have a structure to prevent rollers from falling off to the inner diameter side of the cage, a roller fall-out prevention device has been proposed that is fitted inside the roller inscribed circle of the bearing to prevent the rollers from falling off to the inner diameter side of the cage until the bearing is assembled into the mounting object (application unit).

[0004] For example, as shown in Figure 6, Patent Document 1 below describes a roller fall-out prevention device 61 which has a single continuous slit 62 formed between both ends of a cylinder having an outer diameter larger than the inscribed circle diameter of the roller of the bearing, and which has elasticity in the opening and closing directions of the slit 62, and which is fitted into the inner periphery of the bearing with the slit 62 in a closed state and the outer diameter of the cylinder reduced to a diameter smaller than the inscribed circle diameter of the roller, and which is then restored to its original state so that the outer periphery abuts against the roller, thereby preventing the roller from falling out towards the inner diameter side of the bearing.

[0005] Furthermore, in Patent Document 2 listed below, as shown in Figure 7, a roller fall-out prevention device 71 is described in which elastic deformation sections 72 that are elastically deformable so as to reduce the circumferential length are provided at two opposing circumferential positions on a cylindrical body, and the elastic deformation sections 72 have a connecting section 74 between a pair of slits 73 cut into opposite axial end faces and offset in the circumferential direction, and the cylindrical body is reduced in diameter to fit into the inner periphery of a bearing, and then restored to its original shape, causing the outer periphery to abut against the rollers, thereby preventing the rollers from falling out towards the inner diameter side of the bearing.

[0006] Furthermore, Patent Document 3 listed below describes a roller fall-out prevention device 81, as shown in Figure 8, in which tapered portions 82 and flanges 83 are formed at one and the other axial ends of a cylindrical body, and V-groove-shaped elastic recessed portions 84 are formed at two locations in the circumferential direction on the outer periphery of the cylindrical body, and the flanges 83 are gripped and the cylindrical body is reduced in diameter while fitting from tapered portion 82 into the inside of the roller inscribed circle of the bearing, and then restored to its original state, causing the outer periphery of the cylindrical body to abut against the roller, thereby preventing the roller from falling out toward the inner diameter side of the bearing.

[0007] Japanese Patent Application Laid-Open No. 2002-81456 Japanese Patent Application Laid-Open No. 2017-160931 Japanese Utility Model Application Laid-Open No. 4-56921

[0008] However, roller disengagement prevention devices 61 such as those shown in Figure 6 require the diameter to be reduced before fitting them into the bearing, which is a time-consuming process. Furthermore, a single slit 62 is formed between both ends in the axial direction, resulting in a so-called split shape, which results in a large deviation in the roller retention force in the circumferential direction. Therefore, in order to ensure sufficient retention force even at the position with the weakest retention force, a considerable thickness is required, which increases material costs. Meanwhile, at the position with the strongest retention force, friction with the bearing is large, making fitting and removal difficult.

[0009] Furthermore, although the roller disengagement prevention device 71 shown in Figure 7 is provided with multiple elastic deformation portions 72, which improves the uniformity of the roller retention force in the circumferential direction, it still needs to be reduced in diameter before being fitted into the bearing, as with the device shown in Figure 6, which can still be inconvenient. In addition, if the cylindrical body is made thin-walled, there is a problem in that when the bearing is assembled into an application unit and then removed from the bearing by pushing the shaft or inner ring in, a sufficient catch cannot be ensured.

[0010] Furthermore, a roller disengagement prevention device 81 as shown in Figure 8 has a tapered portion 82 at one axial end of the cylindrical body, so it can be fitted into the bearing from the small diameter end of the tapered portion 82 without having to be reduced in diameter beforehand. However, since it has a flange 83 at the other end for axial positioning and has an asymmetrical shape in the axial direction, it is necessary to check the axial orientation when fitting it into the bearing, which can be troublesome.

[0011] Therefore, an object of the present invention is to provide a roller fall-out prevention device that is easy to fit into a bearing, uniforms the holding force of the bearing rollers in the axial and circumferential directions, reliably prevents the rollers from falling out, can be easily removed from the bearing, and material costs can be reduced.

[0012] In order to solve the above problems, the present invention provides a roller fall-out prevention device that is applied to a bearing in which rollers fall out on the inner diameter side of the cage, wherein tapered sections are formed on the outer periphery of both axial ends with an incident angle to the bearing of less than 45°, and the outer periphery of the axial middle section is a straight section that forms a cylindrical surface parallel to the axis, and when mounted on the bearing, the small diameter end of either of the tapered sections is inserted inside the inscribed circle of the bearing rollers, and the straight section abuts against the bearing rollers.

[0013] When the roller fall-off prevention device is fitted into the bearing from the small diameter end of the tapered portion, it automatically reduces in diameter as it is inserted into the bearing, so there is no need to reduce the diameter beforehand.

[0014] Furthermore, since the tapered portion and the straight portion are formed so as to be symmetrical in the axial direction, there is no need to check the orientation when fitting the bearing.

[0015] Furthermore, four or more slits are formed alternately at equal intervals in the circumferential direction from each of the two axial end faces, and further, when viewed from each axial end face, the slits are arranged on at least two symmetrical center lines that pass through the center and extend radially.As a result, the slits are arranged at equal intervals in the circumferential direction at opposite positions on either side of the center of each end face, making it possible to uniformize the roller holding force in the axial and circumferential directions, eliminating the need to increase the thickness of the wall in areas where the roller holding force is insufficient and eliminating areas where the roller holding force is excessive.

[0016] In addition, the inner diameter surface has a ridge extending in the axial direction, and two or more of these ridges are provided on the inner diameter surface.The shaft or inner ring is pushed out of the bearing by abutting the end face of the ridge, so that even if the bearing is thin, a sufficient catch for the shaft or inner ring can be ensured.

[0017] Furthermore, because these roller fall-off prevention devices are made from a resin material, the costs required for materials and processing can be reduced compared to metal devices, making them inexpensive, lightweight, and easy to handle.

[0018] The roller fall-out prevention device of this invention has tapered sections formed on the outer periphery of both axial ends, with an incident angle to the bearing of less than 45°, so it can be fitted into the bearing without first reducing its diameter, and there is no need to check the orientation when fitting it, reducing the complexity of the work required to prevent the rollers from falling out.

[0019] When fitted into the bearing, the slits are evenly arranged circumferentially, and the force of the straight sections holding the rollers acts uniformly in both the axial and circumferential directions. This means that even with a thin wall, the rollers can be reliably prevented from falling out, and the material costs required for manufacturing can be reduced.

[0020] Furthermore, since a protrusion is provided on the inner diameter surface, even if the bearing is thin, sufficient engagement can be ensured when removing it from the bearing by pushing it in with the shaft or inner ring, and it can be removed stably and easily without having to precisely position the pushing-in position.

[0021] FIG. 1 is a perspective view of a roller disengagement prevention device according to an embodiment of the present invention; FIG. 2 is a view showing the outer peripheral surface of the same; FIG. 3 is a view showing an end face in the axial direction of the same; FIG. 4 is an explanatory view in the axial direction showing the process of fitting the same into a bearing; FIG. 5 is an explanatory view in the axial direction showing the state of fitting into the bearing; FIG. 6 is a partial cross-sectional view in the radial direction showing the state of the bearing with the roller disengagement prevention device fitted in it attached to an application unit; FIG. 7 is an explanatory view in the axial direction of the same;

[0022] (Configuration of roller disengagement prevention device) The roller disengagement prevention device 1 shown in Figures 1, 2A and 2B is cylindrical and short in the axial direction, with tapered sections 2 formed on the outer periphery of both axial ends and a straight section 3 that forms a cylindrical surface parallel to the axis of the outer periphery of the middle axial section, giving it a symmetrical shape in the axial direction.

[0023] The tapered portion 2 is set so that the angle of incidence α with respect to the bearing is less than 45° (see FIG. 2A). If the angle of incidence α is 45° or more, the tapered portion 2 will abut against the end of the roller when fitting into the bearing, making it difficult to fit into the inner periphery of the bearing.

[0024] The angle of incidence α of the tapered portion 2 with respect to the bearing is preferably 30° or less so that the fitting into the bearing can be performed smoothly, as will be described later, but if it is too small, the effect of smooth fitting into the bearing is reduced. Specifically, from the viewpoint of such functionality and dimensional control during manufacturing, the lower limit is 10°.

[0025] Here, the outer diameter of the small diameter end of the tapered portion 2 is smaller than the inscribed circle of the rollers 13 of the bearing 11 to be mounted, which will be described later, and the outer diameter of the straight portion 3 is larger than the inscribed circle of the rollers 13 of the bearing 11.

[0026] The roller disengagement prevention device 1 has four slits 4 formed alternately at equal intervals in the circumferential direction from each of both axial end faces.

[0027] The number of slits 4 may be more than four, but they should be arranged at equal intervals in the circumferential direction and on at least two center lines when viewed from the end face in the axial direction.

[0028] Furthermore, four axially extending ridges 5 are formed at equal intervals in the circumferential direction on the inner diameter surface of the roller disengagement prevention device 1. When viewed from the axial direction, the ridges 5 have an arc-shaped curved surface, and are positioned midway in the circumferential direction between the slits 4 that are cut alternately from both end faces.

[0029] The number of protrusions 5 is two or more, arranged at equal intervals in the circumferential direction so that when the bearing is removed from the bearing by pushing it with the shaft or inner ring, as described below, a uniform pushing force acts in the circumferential direction.

[0030] From the viewpoint of material cost and weight reduction, it is preferable that such a roller disengagement prevention device 1 be made of a resin material rather than a metal material. Furthermore, a roller disengagement prevention device 1 having such a shape can be easily manufactured by injection molding.

[0031] 3A and 3B show the case where the roller disengagement prevention device 1 described above is attached to a cage-and-roller type bearing 11. This bearing 11 does not have a structure for preventing the cage 12 from disengaging the outer rollers 13 toward the inner diameter side.

[0032] As shown in FIG. 3A, when fitting roller disengagement prevention device 1 into bearing 11, first, one of tapered portions 2 of roller disengagement prevention device 1 is slightly inserted inside the inscribed circle of roller 13 of bearing 11, and then, from that state, force is applied in the axial direction so as to press straight portion 3 inside the inscribed circle of roller 13 of bearing 11.

[0033] When the roller disengagement prevention device 1 is fitted into the inner diameter side of the bearing 11, as shown in FIG. 3B, the straight portion 3 of the roller disengagement prevention device 1 abuts against the rollers 13 of the bearing 11, preventing the rollers 13 from disengaging from the cage 12 toward the inner diameter side.

[0034] The roller fall-out prevention device 1 as described above has tapered sections 2 formed on the outer periphery of both axial ends, with an incident angle to the bearing 11 of less than 45°, so that it can be fitted into the bearing 11 with a relatively small force without having to reduce the diameter beforehand, and there is no need to check the orientation when fitting, reducing the complexity of the work required to prevent the rollers 13 from falling out.

[0035] When fitted into the bearing 11, the slits 4 formed alternately from both axial end faces are evenly arranged in the circumferential direction, and the holding force of the rollers 13 by the straight portion 3 acts uniformly in the axial and circumferential directions. Therefore, even with a thin wall, the rollers 13 can be reliably prevented from falling off, and the material costs required for manufacturing can be reduced.

[0036] Furthermore, even for bearings 11 having rollers 13 with different inscribed circle diameters, as long as the tapered portion 2 is within a range in which it abuts against the rollers 13 when the roller disengagement prevention device 1 is fitted into the bearing 11, the roller disengagement prevention device 1 described above can be applied to prevent the rollers 13 from falling out of the cage 12 toward the inner diameter side.

[0037] (Mounting of bearing to application unit) The bearing 11 fitted with the roller fall-out prevention device 1 in this manner can be mounted on the inner diameter side of the outer member 22 of the application unit 21 with the rollers 13 held by the retainer 12, as shown in Figures 4A and 4B.

[0038] (Removal from bearing) When removing the roller disengagement prevention device 1 from the bearing 11 attached to the outer member 22 of the application unit 21, as shown in Figure 5, the inner member 23, which is the shaft or inner ring of the application unit 21, is abutted against the end face of the protrusion 5 of the roller disengagement prevention device 1 and force is applied in the axial direction to push the roller disengagement prevention device 1 out of the bearing 11.

[0039] The roller disengagement prevention device 1 as described above is provided with the ribs 5 on the inner diameter surface, so that even if it is thin-walled, when it is removed from the bearing 11 by pushing in the inner member 23, which is the shaft or inner ring, a sufficient catch can be ensured, and it can be removed stably and easily without strict positioning of the pushing-in position.

[0040] Furthermore, since two or more ridges 5 are formed at equal intervals in the circumferential direction, when the inner member 23 is pushed in to remove it from the bearing 11, a uniform pushing force acts in the circumferential direction, and the roller disengagement prevention device 1 is not pushed in a direction deviating from the axis of the bearing 11, which would increase resistance.

[0041] REFERENCE SIGNS LIST 1 Roller fall-off prevention tool 2 Tapered portion 3 Straight portion 4 Slit 5 Protrusion 11 Bearing 12 Cage 13 Roller 21 Application unit 22 Outer member 23 Inner member

Claims

1. A cylindrical roller fall-out prevention device applied to a bearing in which the rollers fall out onto the inner diameter side of the cage, wherein the outer periphery of both axial ends of the roller fall-out prevention device is tapered with an incident angle of less than 45° to the bearing, and the outer periphery of the axial middle part is a straight part that forms a cylindrical surface parallel to the axis, and the straight part comes into contact with the rollers of the bearing.

2. A roller dislodging prevention device as described in claim 1, wherein the tapered portion and the straight portion are formed so as to be symmetrical in the axial direction.

3. A roller fall-off prevention device as claimed in claim 1 or 2, in which four or more slits are formed alternately at equal intervals in the circumferential direction from each of both axial end faces.

4. A roller fall-off prevention device as described in claim 3, wherein the slits are arranged on at least two symmetrical center lines when viewed from each end face in the axial direction.

5. A roller dislodging prevention device as claimed in any one of claims 1 to 4, which has a protrusion extending in the axial direction on its inner diameter surface, and which is pushed out of the bearing by abutting the shaft or inner ring against the end face of said protrusion.

6. A roller fall-off prevention device as set forth in claim 5, wherein two or more of the ridges are provided on the inner diameter surface.

7. A roller fall-off prevention device according to any one of claims 1 to 6, which is made of a resin material.

8. A bearing with a roller disengagement prevention device, comprising: a bearing that does not have a structure to prevent rollers from falling off toward the inner diameter side of the cage; and a roller disengagement prevention device as claimed in any one of claims 1 to 6, wherein the roller disengagement prevention device is fitted inside the roller inscribed circle of the bearing.

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