Roller bearings

Abstract

To provide a roller bearing that is configured simply but can prevent a roller from falling on an inner diameter side.SOLUTION: A roller bearing includes: a plurality of rollers; and a retaining part for retaining the rollers in a circumferential direction. The retaining part includes: a pair of rib parts separated from each other in an axial direction; an outside column part radially outside of PCD of the rollers; and an inside column part radially inside of PCD of the rollers, where the outside column part and the inside column part are not connected in other parts than the rib part.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to roller bearings.

Background Art

[0002] For example, roller bearings used in general industrial machines such as automotive mechanism parts and robot mechanism parts are required to save space and have a high load capacity. A roller bearing includes a plurality of rollers and a holding component (including a cage) that holds the rollers in the circumferential direction. The cage has a pair of annular portions spaced apart in the axial direction and a plurality of column portions extending in the axial direction to connect the annular portions to each other. Then, the rollers are held rotatably in pockets formed between adjacent column portions along the circumferential direction.

[0003] In a roller bearing, in order to increase the load capacity, it is effective to increase the number of rollers. The one described in Patent Document 1 is a high-load capacity needle roller bearing used in a speed reducer or the like that decelerates the rotation of a hydraulic motor provided in a construction machine. The column portion of the cage is provided radially outward of the PCD of the rollers. Thereby, the circumferential distance between the rollers can be shortened, and the number of rollers can be increased.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] To reduce the gap between rollers, the column section is positioned only on the outer diameter side of the PCD (pitch circle diameter) of the roller, as described in Patent Document 1. Alternatively, if the column section is continuous from the outer diameter side to the inner diameter side, the column width must be made thin in relation to the PCD. When the column section is configured in this way, the rollers will fall out on the inner diameter side. To prevent the rollers from falling out, it is necessary to separately incorporate a component such as a resin sleeve on the inner diameter side.

[0006] In view of the above circumstances, the present invention aims to provide a roller bearing that can prevent the rollers from falling out towards the inner diameter side with a simple configuration. [Means for solving the problem]

[0007] The roller bearing according to the present invention comprises a plurality of rollers and a retaining component that holds the rollers in the circumferential direction, wherein the retaining component comprises a pair of rib portions spaced apart in the axial direction, an outer column portion radially outward from the PCD of the rollers, and an inner column portion radially inward from the PCD of the rollers, and the outer column portion and the inner column portion are not connected except by the rib portions.

[0008] In this invention, the structure comprises an outer column section and an inner column section, which are not connected except by the rib section. That is, each column section has an independent structure on the outer diameter side and the inner diameter side. The inner column section can support the roller on the inner diameter side, thus providing a fall prevention mechanism that prevents the roller from falling out to the inner diameter side without the need for a separate member.

[0009] The roller has chamfered portions at both axial ends, and the outer column portion and the inner column portion can be set to a range where the pocket corner portion and the chamfered portion do not interfere with each other.

[0010] In the above configuration, an outer member having a raceway surface may be provided. In this case, the outer member is an outer ring disposed on the outer circumference side of the roller, and the retaining component can be an outer diameter guide type retaining component whose outer diameter surface contacts the outer ring raceway surface. Alternatively, an outer ring may not be provided, in which case it can be an outer diameter guide type retaining component that contacts an outer member (housing, etc.) having a raceway surface.

[0011] In the above configuration, the rollers may be in contact with each other. That is, the roller bearing of the present invention can be a so-called full-roller bearing in which the rollers are in contact with each other.

[0012] In the above configuration, the pocket width P2 in the inner diameter column portion may be larger than the pocket width P1 in the outer diameter column portion. This makes it easier to assemble the rollers from the inner diameter side.

[0013] The retaining component can be made of a metal material or a polymer material. [Effects of the Invention]

[0014] According to the present invention, it is possible to prevent the rollers from falling off towards the inner diameter side with a simple configuration. [Brief explanation of the drawing]

[0015] [Figure 1] This is a partial cross-sectional view showing a roller bearing according to the first embodiment of the present invention. [Figure 2] This is a perspective view of the cage constituting the roller bearing according to the first embodiment. [Figure 3] This is a cross-sectional view showing the entire cage of the roller bearing according to the first embodiment. [Figure 4] This is an enlarged cross-sectional view along line AA in Figure 1. [Figure 5] This diagram illustrates the relationship between the axial lengths of the roller and retainer pockets. [Figure 6] This is a partial cross-sectional view showing a roller bearing according to a second embodiment of the present invention. [Figure 7] It is an enlarged cross-sectional view taken along line A-A of another cage in which the cross-sectional shape of the column portion is different in FIG. 1.

Embodiments for Carrying out the Invention

[0016] [[ID=�10]]A first embodiment of the roller bearing of the present invention will be described based on FIGS. 1 to 5. The roller bearing in FIG. 1 shows a cylindrical roller bearing. In the following description, the direction along the bearing center axis (not shown) is referred to as the "axial direction", the direction orthogonal to the bearing center axis is referred to as the "radial direction", and the circumferential direction around the bearing center axis is referred to as the "circumferential direction".

[0017] The roller bearing includes an outer member 1, a predetermined number of rolling elements 2 disposed on the inner diameter side of the outer member 1, and a holding component 3 that holds the rolling elements 2.

[0018] The outer member 1 is an outer ring whose inner diameter surface serves as a raceway surface 4. Further, as an inner member (not shown) coaxial with the outer member 1, an inner ring whose outer diameter surface serves as a raceway surface may be provided. Further, as the inner member, a shaft or a housing having a raceway surface may be provided. A second raceway ring (inner ring) may be provided.

[0019] The rolling element 2 is a cylindrical roller in this embodiment, and is hereinafter referred to as "roller 2". As shown in FIGS. 1 and 5, the roller 2 has chamfered portions 5a and 5b having an R shape at both axial ends.

[0020] [[ID=2५]] The holding component 3 is a cage that holds the rollers 2 equidistantly on the circumference, and is hereinafter referred to as "cage 3". As shown in FIGS. 1, 2, 3, and 4, the cage 3 includes a plurality of outer column portions 6 arranged at regular intervals in the circumferential direction, a plurality of inner column portions 7 arranged at regular intervals in the circumferential direction on the inner diameter side of the outer column portions 6, a first rib portion 8a continuous in the circumferential direction on one end side (one axial side, left side in the figure) of these outer column portions 6 and inner column portions 7, and a second rib portion 8b continuous in the circumferential direction on the other end side (the other axial side, right side in the figure) opposite to one end side of the outer column portions 6 and inner column portions 7 are integrally formed.

[0021] The first rib portion 8a and the second rib portion 8b have the same configuration. As shown in Figures 2 and 3, the first and second rib portions 8a and 8b consist of outer annular portions 9a and 9b that are continuous in the circumferential direction, inner annular portions 10a and 10b that are located on the inner diameter side of the outer annular portions 9a and 9b, have a smaller diameter than the outer annular portions 9a and 9b, and are continuous in the circumferential direction, and ring portions 11a and 11b that continuously connect the outer annular portions 9a and 9b and the inner annular portions 10a and 10b in the radial direction.

[0022] The outer column section 6 connects a pair of outer ring sections 9a and 9b on the outer diameter side of the roller's PCD (pitch circle diameter) (see Figure 4), and multiple outer column sections 6 are arranged at regular intervals in the circumferential direction. Similarly, the inner column section 7 connects a pair of inner ring sections 10a and 10b on the inner diameter side of the roller's PCD (pitch circle diameter) (see Figure 4), and multiple inner column sections 7 are arranged at regular intervals in the circumferential direction. The outer column section 6 and the inner column section 7 are arranged at positions that are almost opposite each other in the radial direction. That is, the outer column section 6 and the inner column section 7 are not connected in the radial direction except for the rib sections 8a and 8b, and each column section has an independent configuration on the outer diameter side and the inner diameter side.

[0023] Multiple pockets 12 are formed between adjacent column sections 6 and 7 in the circumferential direction, and rollers 2 are placed in these pockets 12. The inner column section 7 can support the rollers 2 on its inner diameter side, and serves as a mechanism to prevent the rollers 2 from falling out.

[0024] Stress concentration occurs at the pocket corners 13a and 13b (see Figure 5), so the pocket corners 13a and 13b are R-shaped or have a curved shape that approximates it. The outer column 6 and inner column 7 are positioned so that the pocket corners 13a and 13b do not interfere with the chamfered portions 5a and 5b of the roller 2. That is, the axial length C of the outer column 6 and inner column 7 (see Figures 1 and 5) is preferably the maximum (as long as possible) within the range where the chamfered portions 5a and 5b of the pocket corners 13a and 13b do not interfere. At this time, in order to prevent interference between the roller 2 and the pocket 12, the axial length B of the chamfered portions 5a and 5b of the roller 2 is set to be greater than or equal to the axial length A of the curved portion of the pocket corners 13a and 13b.

[0025] In this embodiment, the retainer 3 is an outer diameter guide type retainer from the viewpoint of securing the cross-sectional area of ​​the column portion. That is, the outer diameter surface of the retainer 3 (the outer diameter surfaces of the outer column portion 6 and the outer ring portions 9a and 9b) comes into contact with the raceway surface 4 of the outer ring 1 during rotation.

[0026] Thus, when the retainer 3 is an outer diameter guide type retainer and the inner column portion 7 serves as a mechanism to prevent the rollers from falling out, it is preferable that the cross-sectional area of ​​the outer column portion 6 is larger than the cross-sectional area of ​​the inner column portion 7 in the cross-sections of the outer column portion 6 and the inner column portion 7 located at the same position in the radial direction (see Figure 4). Furthermore, when used in locations where thrust loads are generated, if there are large and small differences in the cross-sectional shape of the column portions, stress concentration may occur and deformation may occur. Therefore, it is preferable that the outer column portion 6 and the inner column portion 7 each have a cross-sectional shape that is substantially uniform in the axial direction.

[0027] As shown in Figure 4, the pocket width P2 in the inner column 7 is larger than the pocket width P1 in the outer column 6. This makes it easier to install the roller 2 from the inner diameter side.

[0028] The retainer 3 can be constructed from various materials, but from a strength standpoint, an alloy material mainly composed of iron is preferred. Depending on the application, stainless steel alloys are preferred when corrosion resistance is required, nickel alloys when heat resistance is required, and tool steel materials when wear resistance is required. In addition, Ti-based, Al-based, Si-based, and Mo-based alloy steels can be selected according to the purpose. Furthermore, non-metallic materials may be used due to their machinability. For further weight reduction, thermoplastic resin materials based on PEEK, PPS, PES, POM, and PA materials can be selected, and depending on the processing method, thermosetting resins and photocurable resins can also be selected. To further improve the physical properties of each material, heat treatments such as carburizing and nitriding can be performed on alloy materials and non-metallic materials.

[0029] The retainer 3 can be formed by various manufacturing methods. In the case of press forming, the processing steps for removing the space between the outer column 6 and the inner column 7 are numerous, so it may be processed using a 3D printer, machining, casting, sintering, resin molding, or stereolithography. 3D printing methods include forming by spraying metal powder, forming by laser melting and layering while supplying metal powder from a nozzle, forming by melting and solidifying spread metal powder along the sliced ​​cross-section of the workpiece, and forming by extruding, layering, and hardening metal.

[0030] In this embodiment, the inner column portion 7 of the retainer 3 can support the roller 2 on the inner diameter side, thus preventing the roller 2 from falling out on the inner diameter side with a simple configuration without the need for additional components. Furthermore, since the column portions are not continuous in the radial direction and the outer column portion 6 and the inner column portion 7 are independent, it is lighter and generates less torque than when the column portions are continuous in the radial direction. Moreover, when the retainer 3 is manufactured using a 3D printer, the volume is reduced, thus reducing the cycle time.

[0031] Figure 6 shows a second embodiment of the roller bearing of the present invention. In the second embodiment, the inner column portion of the cage is divided in the axial direction. That is, the cage 20 constituting the roller bearing of the second embodiment is integrally formed with a plurality of outer column portions 21 arranged at regular intervals in the circumferential direction, a plurality of inner column portions 22 arranged at regular intervals in the circumferential direction on the inner diameter side of the outer column portions 21, a first rib portion 23a continuous with one end side (one axial side, left side in the figure) of the outer column portions 21 and inner column portions 22, and a second rib portion 23b continuous with the other end side (the other axial side, right side in the figure) opposite to the one end side of the outer column portions 21 and inner column portions 22.

[0032] The rib portions 23a and 23b are composed of outer annular portions 24a and 24b, inner annular portions 25a and 25b, and ring portions 26a and 26b, similar to the first embodiment.

[0033] The outer column section 21 connects a pair of outer annular sections 24a and 24b and is arranged in multiples at regular intervals in the circumferential direction. The inner column section 22 is not continuous in the axial direction but is divided. That is, the inner column section 22 is composed of a first inner column section 22a extending axially outward from the inner annular section 25a that constitutes the first rib section 23a, and a second inner column section 22b extending axially inward from the inner annular section 25b that constitutes the second rib section 23b. In this embodiment as well, the outer column section 21 and the inner column section 22 are arranged at positions that are substantially opposite each other in the radial direction at their respective locations, and each column section has an independent configuration on the outer diameter side and the inner diameter side.

[0034] In this second embodiment of the roller bearing, the inner column portions 22a and 22b of the cage 20 can support the roller 2 on the inner diameter side, thus providing a mechanism to prevent the roller 2 from falling out. Moreover, it is lighter than the roller bearing of the first embodiment. In the roller bearing shown in Figure 6, components similar to those in the roller bearing shown in Figure 1 are given the same reference numerals as in Figure 1, and their descriptions are omitted.

[0035] In the first and second embodiments described above, as shown in Figure 7, the circumferential end faces of the outer column portion 31 and / or the inner column portion 32 may be inclined surfaces that slope along the circumferential direction. That is, as shown in Figure 7(a), the circumferential end face 33 of the outer column portion 31 is an inclined surface that approaches the roller 2 from the inner diameter side to the outer diameter side, and the circumferential end face 34 of the inner column portion 32 is an inclined surface that approaches the roller 2 from the outer diameter side to the inner diameter side.

[0036] Furthermore, as shown in Figure 7(b), the circumferential end face 43 of the outer column portion 41 is composed of an inclined surface 44 on the inner diameter side that approaches the roller 2 from the inner diameter side toward the outer diameter side, and a radial surface 45 that extends radially on the outer diameter side. In addition, the circumferential end face 46 of the inner column portion 42 is composed of an inclined surface 47 on the outer diameter side that approaches the roller 2 from the outer diameter side toward the inner diameter side, and a radial surface 48 that extends radially on the inner diameter side.

[0037] By configuring the outer column section 31 and / or the inner column section 32 as shown in Figure 7(a), or by configuring the outer column section 41 and / or the inner column section 42 as shown in Figure 7(b), the outer column sections 31, 41 and / or the inner column sections 32, 42 can secure a large cross-sectional area within the space of the pockets 35, 49, thereby improving the column strength.

[0038] The roller bearing of the present invention may be a so-called full-roller bearing in which the rollers are in contact with each other. In this case, the roller bearing will be equipped with retaining parts that prevent the rollers from falling out and restrain their axial movement.

[0039] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified in various ways. The rollers are not limited to cylindrical rollers, but can be various types such as needle rollers. The retainer may be an outer ring guide, a roller guide, or an inner ring guide. In addition, in the above embodiments, inner columns were provided at positions opposite all outer columns, but it is not necessary to provide inner columns corresponding to all outer columns. The number of outer columns and inner columns may differ as long as the rollers can be prevented from falling out. That is, the number of inner columns can be greater or less than the number of outer columns. [Explanation of symbols]

[0040] 1. Outer member (outer ring) 2 around 3, 20 retainer 4 Raceway surface 6, 21, 31, 41 Outer pillar section 7, 22, 32, 42 Inner column part 8a, 8b, 23a, 23b Rib section 13a, 13b Pocket corners P1, P2 pocket width

Claims

1. In a roller bearing comprising a plurality of rollers and a retaining component that holds the rollers in the circumferential direction, The retaining component comprises a pair of rib portions spaced apart in the axial direction, an outer column portion radially outward from the PCD of the roller, and an inner column portion radially inward from the PCD of the roller, wherein the pocket width P2 in the inner column portion is set to be larger than the pocket width P1 in the outer column portion, and the retaining component is an outer diameter guide type retaining component whose outer diameter surface contacts an outer member having a raceway surface, wherein in the cross-sections of the outer column portion and the inner column portion located at the same position in the radial direction, the cross-sectional area of ​​the outer column portion is larger than the cross-sectional area of ​​the inner column portion, and each of the outer column portion and the inner column portion has a substantially uniform cross-sectional shape in the axial direction, and the outer column portion and the inner column portion are not connected except by the rib portion.

2. The roller bearing according to claim 1, characterized in that the roller has chamfered portions at both axial ends, and the outer column portion and the inner column portion are within a range where the pocket corner portion and the chamfered portion do not interfere with each other.

3. A roller bearing according to claim 1 or 2, characterized by comprising an outer member having a raceway surface.

4. A roller bearing according to any one of claims 1 to 3, characterized in that the rollers are in contact with each other.

5. The roller bearing according to any one of claims 1 to 4, characterized in that the retaining component is made of a metal material.

6. The roller bearing according to any one of claims 1 to 4, characterized in that the retaining component is made of a polymer material.

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