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

Abstract

To provide a roller fall-off prevention tool that facilitates easy fitting into a bearing, equalizes retention force of the bearing rollers in axial and circumferential directions to reliably prevent roller detachment, allows for easy removal, and also contributes to material cost reduction.SOLUTION: 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 an 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°. An outer periphery of an intermediate portion in the axial direction is a straight portion 3 forming a cylindrical surface parallel to an axis line. 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 an inner side of an inscribed circle of the roller 13 from a small-diameter end of the tapered portion 2. When the tool is removed from the bearing 11, the shaft or an inner ring is abutted against a ridge 5 extending in the axial direction on an inner diameter surface.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a jig for preventing rollers from falling off a roller bearing which rotatably supports parts that are subjected to large centrifugal forces due to revolution, such as planetary gears in an automatic transmission of an automobile or the big end of a connecting rod in an internal combustion engine. [Background technology]

[0002] A cage-and-roller type bearing, which is a typical example of a needle roller bearing, does not have an inner ring or an outer ring, and the cage is usually structured to prevent the rollers from falling off to the outer diameter side and the inner diameter side. However, in a bearing with a large number of rollers, the column width between the cage pockets cannot be secured, and a structure that can prevent the rollers from falling off to the inner diameter side cannot be achieved. Even in a shell-type needle bearing without an inner ring, some do not have a structure that can prevent the rollers from falling off 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 the rollers from falling off into 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 into the inner diameter side of the cage until the bearing is assembled into the mounting object (application unit).

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

[0005] Furthermore, in the following Patent Document 2, as shown in FIG. 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 cylinder, and the elastic deformation sections 72 have a connecting section 74 between a pair of slits 73 cut in from opposite axial end faces, each offset in the circumferential direction, and the cylinder 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 toward the inner diameter side of the bearing.

[0006] Furthermore, the following Patent Document 3 describes a roller fall-out prevention device 81, as shown in FIG. 8, in which a tapered portion 82 and a flange 83 are formed at one and the other axial ends of a cylindrical body, and V-groove-shaped elastic concave portions 84 are provided at two circumferential locations on the outer periphery of the cylindrical body, and the flange 83 is grasped and the cylindrical body is fitted into the inside of the roller inscribed circle of the bearing from the tapered portion 82 while reducing the diameter of the cylindrical body, and then is restored to its original state, causing the outer periphery of the cylindrical body to abut against the rollers, thereby preventing the rollers from falling out toward the inner diameter side of the bearing. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2002-81456 A [Patent Document 2] JP 2017-160931 A [Patent Document 3] Japanese Utility Model Application Publication No. 4-56921 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the roller disengagement prevention device 61 as shown in Fig. 6 needs to be reduced in diameter before fitting it into the bearing, which is a hassle. Also, a single slit 62 is formed between both ends in the axial direction, so that it is a so-called one-split shape, and the roller retention force is largely biased in the circumferential direction. Therefore, in order to ensure sufficient retention force even at the position where the retention force is the weakest, it is necessary to make the wall thickness considerable, which increases the material cost, while at the same time, at the position where the retention force is the strongest, the friction force against the bearing is large, making the fitting and removal operations difficult.

[0009] Furthermore, although the roller fall-out prevention device 71 as shown in Fig. 7 is provided with multiple elastic deformation portions 72, and as a result the uniformity of the roller retention force in the circumferential direction is improved, the diameter must be reduced before fitting into the bearing, as with the device shown in Fig. 6, which can still be inconvenient. In addition, if the cylindrical body is made thin-walled, there is a problem that, after the bearing is incorporated into the application unit, a sufficient catch cannot be secured when removing it from the bearing by pushing in the shaft or inner ring.

[0010] Furthermore, a roller disengagement prevention device 81 as shown in FIG. 8 has a tapered portion 82 at one axial end of the cylindrical body, so that it can be fitted into the bearing from the small diameter end of tapered portion 82 without first reducing the diameter. However, the other end has a flange 83 for axial positioning and has an asymmetric shape in the axial direction, so that 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, uniformizes the retaining force of the bearing rollers in the axial and circumferential directions, reliably prevents the rollers from falling off, and can be easily removed from the bearing while reducing material costs. [Means for solving the problem]

[0012] In order to solve the above problems, the present invention provides a roller disengagement prevention device that is applied to a bearing in which rollers fall off onto the inner diameter side of a cage, comprising: The outer periphery of both ends in the axial direction is formed with a tapered section with an incident angle to the bearing of less than 45°, and the outer periphery of the middle part in the axial direction is a straight section that forms a cylindrical surface parallel to the axis, When mounted on a bearing, the small diameter end of any one of the tapered portions is fitted inside the inscribed circle of a roller of the bearing, and the straight portion abuts against the roller of the bearing.

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

[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] In addition, four or more slits are formed alternately at equal intervals in the circumferential direction from each of both 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 opposing positions on either side of the center of each end face in the circumferential direction, which makes it possible to uniformize the roller retention force in the axial and circumferential directions, eliminating the need to make the material thicker for parts where the roller retention force is insufficient and eliminating parts where the roller retention force is excessive.

[0016] In addition, the inner diameter surface has a ridge extending in the axial direction, with two or more ridges being 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 engagement allowance for the shaft or inner ring can be secured.

[0017] Furthermore, because these roller anti-fall-out devices are made from a resin material, the costs of materials and processing can be reduced compared to metal devices, making them inexpensive to provide and lightweight and easy to handle. Effect of the Invention

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

[0019] Furthermore, when inserted into the bearing, the slits are evenly arranged in the circumferential direction and the retaining force of the rollers by the straight sections acts uniformly in the axial and circumferential directions, so that even with a thin wall, the rollers can be reliably prevented from falling off and the material costs required for manufacturing can be reduced.

[0020] Furthermore, by providing a protrusion on the inner diameter surface, even if the bearing is thin, a sufficient amount of engagement can be secured 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. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a perspective view showing a roller fall-off prevention device according to an embodiment of the present invention; [Diagram 2] (2A) is a diagram showing the outer peripheral surface, and (2B) is a diagram showing the end surface in the axial direction. [Diagram 3] (3A) is an explanatory diagram of the axial direction showing the fitting process into the bearing, and (3B) is an explanatory diagram of the axial direction showing the fitted state into the bearing. [Figure 4] (4A) is a radial partial cross-sectional view showing the state in which the bearing with the roller fall-off prevention device is fitted to the application unit, and (4B) is an axial explanatory view. [Diagram 5] FIG. 11 is an explanatory diagram of the axial direction showing the process of removing the bearing from the application unit. [Figure 6] FIG. 1 is a perspective view showing a roller fall-off prevention device described in Patent Document 1. [Figure 7] FIG. 1 is a perspective view showing a roller fall-off prevention device described in Patent Document 2. [Figure 8] FIG. 1 is a perspective view showing a roller fall-off prevention device described in Patent Document 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0023] The tapered portion 2 is set so that the incident angle α with respect to the bearing is smaller than 45° (see FIG. 2(2A)). If the incident angle α is 45° or more, the tapered portion 2 hits the end of the roller when fitting into the bearing, making it difficult to fit into the inner circumference 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 tapered portion 2 can be smoothly fitted into the bearing as described below, but if the angle is too small, the effect of making the tapered portion 2 smoothly fitted into the bearing is reduced. Specifically, from the viewpoints 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 thereon (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] Further, the roller disengagement prevention device 1 has four slits 4 formed alternately at equal intervals in the circumferential direction from both end faces in the axial direction.

[0027] The number of slits 4 formed 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. The ridges 5 have an arc-shaped curved surface when viewed from the axial direction, and are located midway in the circumferential direction between the slits 4 that are alternately provided from both end faces.

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

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

[0031] (Fitting of roller fall-off prevention devices into bearings) 3(3A) and 3(3B) show the above-mentioned roller disengagement prevention device 1 being attached to a cage-and-roller type bearing 11. This bearing 11 does not have a structure for preventing the cage 12 from disengaging from the outer rollers 13 to the inner diameter side.

[0032] As shown in Figure 3 (3A), when fitting roller fall-off prevention device 1 into bearing 11, first, one of tapered portions 2 of roller fall-off 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] Then, when the roller fall-off prevention device 1 is fitted into the inner diameter side of the bearing 11, the straight portion 3 of the roller fall-off prevention device 1 abuts against the rollers 13 of the bearing 11, as shown in Figure 3 (B), preventing the rollers 13 from falling out of the retainer 12 to the inner diameter side.

[0034] The roller fall-off prevention device 1 as described above has tapered sections 2 formed on the outer periphery of both axial ends, with the angle of incidence with respect to the bearing 11 being less than 45°. As a result, it can be fitted into the bearing 11 with a relatively small force without having to reduce the diameter in advance, 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 off.

[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 portions 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 if the inscribed circle diameter of the rollers 13 in the bearing 11 is different, as long as the tapered portion 2 is within the range in which the roller disengagement prevention device 1 abuts against the rollers 13 when the roller disengagement prevention device 1 is fitted into the bearing 11, the above-mentioned roller disengagement prevention device 1 can be applied to prevent the rollers 13 from falling out of the cage 12 toward the inner diameter side.

[0037] (Mounting the bearing to the application unit) The bearing 11 with the roller fall-out prevention device 1 fitted 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 4 (4A) and 4 (4B).

[0038] (Removal from bearing) When removing the roller fall-off 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 fall-off prevention device 1 and force is applied in the axial direction to push the roller fall-off prevention device 1 out of the bearing 11.

[0039] The roller fall-out prevention device 1 as described above has a rib 5 formed on its 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 amount of engagement can be secured, and it can be removed stably and easily without having to determine the precise position of the push-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, thereby preventing an increase in resistance. [Explanation of symbols]

[0041] 1 Roller fall prevention device 2 Tapered section 3 Straight section 4 Slit 5 protrusions 11 Bearings 12 Cage 13 Around 21 Application Unit 22 Outer member 23 Inner member

Claims

1. A cylindrical roller dropout prevention device applied to a bearing in which rollers fall off to the inner diameter side of the cage, The roller disengagement prevention device has tapered portions formed on the outer periphery of both axial ends thereof, the tapered portions having an incident angle with respect to the bearing of less than 45°, and the outer periphery of the intermediate portion in the axial direction is a straight portion forming a cylindrical surface parallel to the axis, A roller fall-off prevention device in which the straight portion abuts against the roller of a bearing.

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

3. 2. A roller disengagement prevention device according to claim 1, wherein four or more slits are formed alternately at equal intervals in the circumferential direction from each of both axial end faces.

4. 4. A roller disengagement prevention device according to 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. The inner diameter surface has a protrusion extending in the axial direction.

2. A roller disengagement prevention device according to claim 1, wherein the roller is pushed out of the bearing by abutting an end face of the ridge with a shaft or an inner ring.

6. 6. A roller disengagement prevention device according to claim 5, wherein the projection is provided on the inner diameter surface in two or more rows.

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

8. A bearing having no structure for preventing rollers from falling off the inner diameter side of a cage, and a roller fall-off prevention device according to any one of claims 1 to 6, A bearing with roller disengagement prevention devices, characterized in that the roller disengagement prevention devices are fitted inside the roller inscribed circles of the bearing.

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