Roller and needle roller bearings

Abstract

To provide a roller bearing and a needle roller bearing capable of improving the strength by increasing the cross section area of each pillar part, and of improving the basic dynamic (static) rated load by increasing the number of rollers.SOLUTION: To enlarge an area on the pocket inner side, opposed faces of the pillar part opposed to each other along the peripheral direction are formed as inclined faces. When the inclination angle of each inclined face is θ, 20°≤θ≤60°is established. The inclination angle is an angle to a radial line passing through a pocket center.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a roller bearing and a needle roller bearing. [Background technology]

[0002] A conventional roller bearing is a large load capacity roller bearing used for slowing down the rotation of a hydraulic motor installed in a construction machine (Patent Document 1). That is, the roller bearing described in Patent Document 1 has a plurality of rollers 1 arranged circumferentially and held at equal intervals by a cage 2, as shown in Fig. 14.

[0003] In this case, as shown in Figures 15 and 16, the retainer 2 has two circular flanges 3a, 3b and a number of column portions 4 connecting the circular flanges 3a, 3b, and the needle rollers 1 are accommodated in pockets 5 formed between adjacent column portions. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-46792 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, when the column portion 4 is disposed near the roller pitch circle P, it is necessary to make the width dimension of this column portion 4 near the roller pitch circle P smaller than the distance between adjacent rollers in the circumferential direction. In contrast, by disposing the column portion 4 on the outer diameter side of the roller pitch circle P as shown in Fig. 14, the width dimension of the column portion 4 can be made larger.

[0006] However, if an attempt is made to increase the number of rollers in a conventional cage design to improve the basic dynamic (static) load rating, the radial or circumferential width dimension of the column portion will inevitably be reduced, resulting in a decrease in the strength of the column portion.

[0007] In view of the above-mentioned circumstances, the present invention aims to provide a roller bearing and a needle roller bearing in which the cross-sectional shape of the column portion of the retaining member is made to approximate a trapezoid, thereby making effective use of the space between adjacent rollers, thereby improving strength by increasing the cross-sectional area of ​​the column portion and increasing the number of rollers, thereby improving the basic dynamic (static) load rating. [Means for solving the problem]

[0008] The roller bearing of the present invention has a pair of annular portions spaced apart in the axial direction, and a number of column portions extending axially to connect the annular portions, and has a retaining member in which rollers are held in pockets formed between adjacent column portions, the retaining member having inclined surfaces on the column portion opposing surfaces facing each other in the circumferential direction so that the inside of the pocket expands, and when the inclination angle of this inclined surface is θ, 20°≦θ≦60°, and the inclination angle is an angle with a radial line passing through the center of the pocket.

[0009] In the roller bearing of the present invention, the column-part opposing surfaces facing each other in the circumferential direction are inclined so that the pocket inner side is expanded, and therefore the column-part cross-sectional area can be set relatively large even if the column-part is disposed on the outer diameter side or the inner diameter side of the roller pitch circle. Moreover, by setting the inclination angle of the inclined surface of the column-part opposing surface to 20°≦θ≦60°, the space between adjacent rollers can be effectively utilized, and the plate thickness of the column part (radial thickness of the column part) can be set to a thickness that is stable in terms of strength. That is, if θ exceeds 60°, the plate thickness of the column part (radial thickness of the column part) may become too small, or the column part cross-sectional shape may not be able to maintain a shape that is close to a trapezoid. Furthermore, if θ is less than 20°, the width dimension of the column part must be reduced when forming the column part in the space between adjacent rollers, which leads to a decrease in the strength of the column part. Moreover, as for the lower limit, it is preferable to make the column-part cross-sectional area as large as possible, and it is preferable to set it to about 20°, taking into consideration the allowable variation during processing.

[0010] It is preferable that the plate thickness of the column portion (the radial thickness of the column portion) is 10% to 30% of the roller diameter. By setting it in this way, the column portion has a stable strength and can effectively prevent interference between the roller and the retaining member.

[0011] It is preferable that the corners formed between the annular portion and the column of the holding member are curved portions having an R-shape, which can reduce stress generated in the column during processing.

[0012] The R shape of the portion located on the outer diameter side of the curved surface portion can be set to be larger than the R shape of the central portion, or the R shape of the portion located on the inner diameter side of the curved surface portion can be set to be larger than the R shape of the central portion. By setting in this way, it is possible to effectively prevent the generated stress from increasing. Here, a large R shape means a large radius of curvature, and as a result, the distance of the curved surface portion from the annular portion to the column portion becomes longer.

[0013] To improve the basic dynamic (static) load rating, it is preferable to increase the number of rollers and increase the packing ratio. For this reason, the roller packing ratio on the pitch circle of the rollers is set to 93% or more and less than 100%, and the rollers adjacent in the circumferential direction may face each other with a gap when the bearing rotates, or there may be a portion where the rollers adjacent in the circumferential direction contact each other. Here, the roller packing ratio is the proportion of the rollers on the pitch circle, and the roller packing ratio = (Number of rollers x roller diameter) / (Pi x pitch circle diameter) It is expressed as:

[0014] The needle roller bearing of the present invention uses needle rollers for the rollers of the roller bearing. Therefore, the needle roller bearing uses a retaining member that allows the column cross-sectional area to be set relatively large and allows the plate thickness of the column (radial thickness of the column) to be a thickness that provides stable strength. This allows the number of rollers to be increased, improving the basic dynamic (static) load rating of the bearing and providing stable strength. Effect of the Invention

[0015] The present invention makes it possible to increase the number of rollers and improve the basic dynamic (static) load rating without causing a decrease in the strength of the column portion. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is an enlarged perspective view of a main portion of a retaining member for a roller bearing according to the present invention. [Diagram 2] 1 is a simplified diagram of a roller bearing using a retaining member of the present invention. [Diagram 3] FIG. 4 is a cross-sectional view of a main part of a holding member. [Figure 4] FIG. 11 is a cross-sectional view of a main portion of another holding member of the present invention. [Diagram 5] FIG. 4 is an enlarged plan view of a corner portion of the pocket. [Figure 6] FIG. 4 is an enlarged perspective view of a corner of the pocket. [Figure 7] 1 is a simplified diagram of a corner of a pocket. [Figure 8] FIG. 4 is a perspective view of a main part showing a process of processing the holding member of the present invention. [Figure 9] 11 is an enlarged cross-sectional view of a main portion showing a pillar portion of a holding member in the middle of being machined; FIG. [Figure 10] An enlarged cross-sectional view of the main part showing the column portion after processing. [Figure 11] 13 is an enlarged view of a main portion of a retaining member having a pocket with a projection for preventing interference with a roller of the retaining member; FIG. [Figure 12] 12 is a cross-sectional view of a main part of the holding member shown in FIG. 11. [Figure 13] 4 is a cross-sectional view of a main portion of a retaining member disposed on the inner diameter side of the roller pitch circle. FIG. [Figure 14] FIG. 1 is a cross-sectional view of a conventional needle roller bearing. [Figure 15] FIG. 1 is a cross-sectional view of a cage of a conventional needle roller bearing. [Figure 16] FIG. 11 is an enlarged cross-sectional view of a main portion of a cage of a conventional needle roller bearing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to Figures 1 to 13. Figure 1 shows an enlarged perspective view of a main part of a retaining member for a roller bearing of the present invention, and this retaining member 10 has a pair of annular portions 11, 12 spaced apart in the axial direction, and a number of pillar portions 13 extending in the axial direction and connecting the annular portions 11, 12, and rollers 15 (see Figure 2) are housed in pockets 14 formed between adjacent pillar portions 13.

[0018] In this case, as shown in Fig. 3, the opposing surfaces of the columns facing each other along the circumferential direction are inclined surfaces 16a and 16b so that the pocket inner side expands, that is, the pocket 14 expands from the outer diameter side toward the inner diameter side. Therefore, the cross-sectional shape of the column 13 is a shape that approximates a trapezoid. The inclination angle θ (θ1, θ2) of the inclined surfaces 16a and 16b is set to 20°≦θ (θ1, θ2) ≦ 60°. The inclination angle is the angle with a radial line L that passes through the center of the pocket.

[0019] Incidentally, the retaining member 10 is formed by pressing into a molded product S as shown in Fig. 8. In this case, the molded product S has annular portion constituent parts 11A, 12A and a plurality of column portion constituent parts 13A connecting the annular portion constituent parts 11A, 12A with each other, and a pocket portion constituent part 14A formed between adjacent column portion constituent parts 13A, 13A. That is, the column portion facing surfaces facing each other along the circumferential direction of the column portion are not inclined surfaces 16a, 16b, but are end faces 17a, 17b extending in the radial direction as shown in Fig. 9.

[0020] For this reason, as shown in Fig. 10, the end faces 17a, 17b are cut by cutting or the like to produce the inclined faces 16a, 16b. In Fig. 10, the range indicated by the two-dot chain line indicates the removed parts 21a, 21b. In this case, the inclined faces 16a, 16b of the column part 13 may be formed by pressing (surface pressing) processing.

[0021] The method of processing the inclined surfaces 16a, 16b is not limited to pressing, and cutting processes such as broaching and MC milling may be used depending on the production volume and production lead time. Furthermore, if sufficient strength is required, injection molding using resin material or sintering using powder material may be used, and if the size is relatively large, casting may be used. In other words, the material of the retaining member 10 may be metal or synthetic resin that has been conventionally used for retainers, and the molding method may be injection molding, punching (pressing), cutting (machining), etc., depending on the material used.

[0022] However, when the pocket inner diameter width W1 is made larger than the pocket outer diameter width W2, that is, when θ (θ1, θ2) is increased, the cross-sectional shape becomes triangular as shown in FIG. 4. If the cross-sectional shape of the column portion 13 becomes triangular in this way, the radial thickness T of the column portion 13 becomes small, and there is a risk that the strength will not be sufficiently maintained. When θ exceeds approximately 60°, as shown in FIG. 4, when the original plate thickness is T1 (=T) and the plate thickness after processing (after forming the inclined surface) is T2, T1>T2. In addition, the lower limit value is required to make the column portion cross-sectional area as large as possible while effectively utilizing the space 30 between adjacent rollers, and is preferably set to about 20° in consideration of the allowable variation during processing (forming).

[0023] Next, with regard to the preferred angles of the inclination angle θ of the inclined surfaces 16a, 16b of the column portion 13 for the retaining member 10 shown in Figure 1, Table 1 lists the inclination angles θ of the inclined surfaces 16a, 16b that are less than 15°, 15°, 20°, 30°, 40°, 50°, 60°, 65°, and greater than 65°. [Table 1]

[0024] If the inclination angle θ (θ1) (θ2) is 65° or more, the cross-sectional area of ​​the column portion 13 becomes small and the difference between the pocket inner diameter width W1 and the pocket outer diameter width W2 becomes too large, which may result in a decrease in the strength of the column portion 13. In this case, it is marked with × in Table 1. Also, if θ (θ1) (θ2) is 15° or less, it will be impossible to effectively utilize the area H of the space 30 (space shown by hatching in FIG. 2) between the rollers adjacent in the circumferential direction to increase the cross-sectional area of ​​the column portion, which may result in the column portion 13 not being able to maintain sufficient strength. In this case, it is marked with × in Table 1. For this reason, it can be said that it is preferable to set the inclination angle θ (θ1) (θ2) to 20° or more and 60° or less, as marked with ○ in Table 1.

[0025] Next, with respect to the retaining member 10 shown in FIG. 1, preferable ratios of the relationship (T / D) between the thickness (radial thickness of the column portion) T of the retaining member 10 and the roller diameter (roller diameter) D are shown in Table 2 for T / D less than 5%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, and 35% or more. [Table 2]

[0026] If T / D is 35% or more, the rollers 15 and the column portion 13 will interfere relatively strongly, and it will be necessary to reduce the number of rollers or to set the gap between the rollers large, which may prevent the basic dynamic (static) load rating from being improved. In addition, it will be necessary to reduce the width dimension in the circumferential direction of the retaining member, which may prevent the column portion 13 from maintaining sufficient strength. In this case, it is marked with "X" in Table 2. In addition, if T / D is 5% or less, it may prevent the column portion 13 from maintaining sufficient strength. In this case, it is marked with "X" in Table 2. For this reason, as marked with "O" in Table 2, it can be said that it is preferable to set the plate thickness (radial thickness of the column portion) T of the column portion 13 to 10% to 30% of the roller diameter (roller diameter) D (see FIG. 2).

[0027] Incidentally, as shown in FIGS. 5 and 6, the four corners between the annular portion 11(12) and the column portion 13 are formed as R-shaped curved surfaces 22. In this case, as shown in FIG. 7, the R shape of the portion located on the outer diameter side of the curved surface portion 22 is made larger than the R shape of the central portion, and the R shape of the portion located on the inner diameter side is made larger than the R shape of the central portion. Here, a large R shape means a large radius of curvature, and as a result, the distance of the curved surface portion 22 extending from the annular portion 11(12) to the column portion 13 becomes long. That is, the radius of curvature of the portion located on the outer diameter side (outer diameter side portion 22a) is set larger than the radius of curvature of the central portion (central portion in the thickness direction 22c). Also, the radius of curvature of the portion located on the inner diameter side (inner diameter side portion 22b) is set larger than the radius of curvature of the central portion (central portion in the thickness direction 22c). In this case, when the radius of curvature of the outer diameter side portion 22a is R1, the radius of curvature of the inner diameter side portion 22b is R2, and the radius of curvature of the central portion in the thickness direction 22c is R3, R1>R3 and R2>R3, and the generated stress can be reduced in the state where a load is applied to the column portion 13, and the strength of the holding member 10 can be improved. Further, for example, by setting R1≒R2 and making 1.015<(R1≒R2) / R3<1.5, the generated stress can be further reduced in the state where a load is applied to the column portion 13, and the strength of the holding member 10 can be improved. 1.015<(R1≒R2) / R3<1.5 is the case where rolling contact occurs at the center in the radial direction of the surfaces of the columns 14a and 14b. On the other hand, there are cases where the rolling is set closer to the inner diameter or the outer diameter of the columns 14a and 14b. In this case, by setting 0.6<R1 / R3<1.5 and 0.6<R2 / R3<1.5, the strength of the holding member 10 can be improved. The R shape of the portion located on the outer diameter side is made larger than the R shape of the central portion, and the R shape of the portion located on the inner diameter side is made larger than the R shape of the central portion. Here, a large R shape means a large radius of curvature, and as a result, the distance of the curved surface portion extending from the annular portion to the column portion becomes long. That is, the radius of curvature of the portion located on the outer diameter side (outer diameter side portion 22a) is set larger than the radius of curvature of the central portion (central portion in the thickness direction 22c). Also, the radius of curvature of the portion located on the inner diameter side (inner diameter side portion 22b) is set larger than the radius of curvature of the central portion (central portion in the thickness direction 22c). In this case, when the radius of curvature of the outer diameter side portion 22a is R1, the radius of curvature of the inner diameter side portion 22b is R2, and the radius of curvature of the central portion in the thickness direction 22c is R3, R1>R3 and R2>R3, and the generated stress can be reduced in the state where a load is applied to the column portion 13, and the strength of the holding member 10 can be improved. Further, for example, by setting R1≒R2 and making 1.015<(R1≒R2) / R3<1.5, the generated stress can be further reduced in the state where a load is applied to the column portion 13, and the strength of the holding member 10 can be improved. 1.015<(R1≒R2) / R3<1.5 is the case where rolling contact occurs at the center in the radial direction of the surfaces of the columns 14a and 14b. On the other hand, there are cases where the rolling is set closer to the inner diameter or the outer diameter of the columns 14a and 14b. In this case, by setting 0.6<R1 / R3<1.5 and 0.6<R2 / R3<1.5, the strength of the holding member 10 can be improved.

[0028] FIGS. 11 and 12 show that a rolling interference prevention projection 25 that bulges into the pocket is provided at the middle portion of the short side portion 24 of the pocket 14 in the annular portion 11(12). By providing this rolling interference prevention projection 25, interference between the holding member 10 and the rolling element 15 is effectively prevented.

[0029] Incidentally, in the above embodiment, the retaining member 10 is disposed on the outer diameter side of the roller pitch circle P, but the retaining member 10 may be disposed on the inner diameter side of the roller pitch circle P. In this case, as shown in Fig. 13, the pocket 14 is expanded from the inner diameter side toward the outer diameter side, and in order to expand the inside of the pocket, the column portion opposing surfaces opposing along the circumferential direction are made into inclined surfaces 16a, 16b, the column portion cross-sectional shape is made into a shape that approximates a trapezoid, and when the inclination angle of the inclined surfaces 16a, 16b is θ, it satisfies 20°≦θ≦60°.

[0030] In the roller bearing of the present invention, the column-part opposing surfaces that face each other along the circumferential direction are inclined surfaces 16a and 16b so that the pocket inner side is enlarged, and therefore the column-part cross-sectional area can be set relatively large even if the column-part opposing surfaces are disposed on the outer diameter side or the inner diameter side of the roller pitch circle P. That is, the column-part cross-sectional area can be made as large as possible by effectively utilizing the space 30 between adjacent rollers (the space on the outer diameter side of the roller pitch circle P or the space on the inner diameter side of the roller pitch circle P). Moreover, by setting the inclination angle of the inclined surfaces 16a and 16b of the column-part opposing surfaces to 20°≦θ≦60°, the plate thickness (radial thickness of the column part) of the column part 13 can be set to a thickness that is stable in terms of strength. That is, if θ exceeds 60°, the plate thickness (radial thickness of the column part) of the column part 13 may become too small, or the column-part cross-sectional shape may not be able to maintain a shape that is close to a trapezoid. Furthermore, if θ is less than 20°, when forming the column portion in the space between adjacent rollers, the width dimension of the column portion 13 must be reduced, resulting in a decrease in the strength of the column portion. As for the lower limit, it is preferable to make the column portion cross-sectional area as large as possible, and taking into account the allowable variation during processing, it is preferable to set it at around 20°.

[0031] Therefore, the present invention makes it possible to increase the number of rollers and improve the basic dynamic (static) load rating without decreasing the strength of the column portion 13. Also, it is preferable to set the plate thickness (radial thickness of the column portion) T of the column portion 13 to 10% to 30% of the roller diameter D. By setting it in this way, the column portion 13 is stable in terms of strength.

[0032] It is preferable that the corner portion between the annular portion 11(12) and the column portion 13 is a curved surface portion 22 with an R shape. By setting it in this way, the stress generated in the column portion 13 during processing can be relaxed.

[0033] Regarding the R shape of the portion located on the outer diameter side in the curved surface portion 22, it is made larger than the R shape of the central portion, and the R shape of the portion located on the inner diameter side is also made larger than the R shape of the central portion. That is, the radius of curvature of the portion located on the outer diameter side (outer diameter side portion 22a) is set larger than the radius of curvature of the central portion (central portion in the thickness direction 22c). Also, the radius of curvature of the portion located on the inner diameter side (inner diameter side portion 22b) is set larger than the radius of curvature of the central portion (central portion in the thickness direction 22c). In this case, when the radius of curvature of the outer diameter side portion 22a is R1, the radius of curvature of the inner diameter side portion 22b is R2, and the radius of curvature of the central portion in the thickness direction 22c is R3, R1 > R3 and R2 > R3. In a state where a load is applied to the column portion 13, the generated stress can be reduced, and the strength of the holding member 10 can be improved. Also, for example, by setting R1 ≒ R2 and making 1.015 < (R1 ≒ R2) / R3 < 1.5 approximately, the generated stress can be further reduced in a state where a load is applied to the column portion 13, and the strength of the holding member 10 can be improved. 1.015 < (R1 ≒ R2) / R3 < 1.5 is the case when rolling contact occurs at the center in the radial direction of the surfaces of the columns 14a and 14b. On the other hand, there may be a case where the rolling is set closer to the inner diameter or the outer diameter of the columns 14a and 14b. In this case, by making 0.6 < R1 / R3 < 1.5 and 0.6 < R2 / R3 < 1.5 approximately, the strength of the holding member 10 can be improved.

[0034] Even if the rollers adjacent to each other in the circumferential direction face each other with a gap, or even if they have a portion where the rollers adjacent to each other in the circumferential direction are in contact.

[0035] The needle roller bearing of the present invention uses the above-mentioned retaining member 10. Therefore, this needle roller bearing uses retaining member 10 which allows the cross-sectional area of ​​the column portion to be set relatively large, and further allows the plate thickness of column portion 13 (radial thickness of the column portion) to be a thickness that provides stable strength, and by increasing the number of rollers, the basic dynamic (static) load rating of the bearing can be improved, and the strength is stable.

[0036] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and various modifications are possible. The roller bearing may be one in which adjacent rollers face each other with a gap therebetween, or one in which adjacent rollers contact each other in the circumferential direction. The roller bearing is not limited to a needle roller bearing, but may be a cylindrical roller bearing or a tapered roller bearing. The bearing is not limited to a single-row type, but may be a double-row type. The roller bearing in which the retaining member is used is, for example, one used in general industrial machinery, but can be particularly used in those requiring space saving and high load capacity, for example, in automotive machine parts and robot mechanism parts.

[0037] The retaining members shown in Figures 1 to 4 are disposed on the outer diameter side of the roller pitch circle, and therefore can be of the outer ring guide type as a roller bearing. Here, outer ring guide means that the retaining member is positioned by abutting against the outer ring, and the outer surface serves as a guide surface and abuts against the inner circumference of the outer ring. The retaining member shown in Figure 13 is disposed on the inner diameter side of the pitch circle, and therefore can be of the inner ring guide type as a roller bearing. Here, inner ring guide means that the retaining member is positioned by abutting against the inner ring, and the inner surface serves as a guide surface and abuts against the outer circumference of the inner ring. [Explanation of symbols]

[0038] 10 Retaining member 11,12 Annular section 13 Pillar section 14 Pockets Around 15 16a, 16b Slope 22 Curved section 22a Outer diameter side part 22b Inner diameter side part 22c Thickness direction central part

Claims

1. A roller bearing having 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, the rollers being held in pockets formed between adjacent column portions, The retaining member has inclined surfaces on opposing column portions that face each other in the circumferential direction so that the inside of the pocket expands, and when the inclination angle of this inclined surface is θ, it is 20°≦θ≦60°, and the inclination angle is an angle with a radial line passing through the center of the pocket, and a corner formed between the annular portion and the column portion of the retaining member is an R-shaped curved portion, and the R-shape of the curved portion at the outer diameter side is set to be larger than the R-shape of a central portion.

2. A roller bearing having a pair of annular portions spaced apart in the axial direction and a plurality of pillar portions extending in the axial direction to connect the annular portions, the rollers being held in pockets formed between adjacent pillar portions, the roller bearing having a retaining member, The retaining member has inclined surfaces on opposing column portions that face each other in the circumferential direction so that the inside of the pocket expands, and when the inclination angle of this inclined surface is θ, it is 20°≦θ≦60°, and the inclination angle is an angle with a radial line passing through the center of the pocket, and a corner formed between the annular portion and the column portion of the retaining member is an R-shaped curved portion, and the R-shape of the curved portion at the portion located on the inner diameter side is set to be larger than the R-shape of a central portion.

3. 3. A roller bearing according to claim 1, wherein the radial thickness of the column portion is 10% to 30% of the roller diameter.

4. 4. A roller bearing according to claim 1, further comprising portions where adjacent rollers in the circumferential direction come into contact with each other.

5. A needle roller bearing, characterized in that needle rollers are used as the rollers of the roller bearing described in any one of claims 1 to 4.

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