JP7627636B2 - Roller and needle roller bearings - Google Patents

Description

The present invention relates to roller bearings and needle roller bearings.

Conventionally, roller bearings include high-load capacity roller bearings used to slow down the rotation of hydraulic motors installed in construction machinery (Patent Document 1). That is, the roller bearing described in Patent Document 1, as shown in Figure 14, is made up of multiple rollers 1 arranged circumferentially and held at equal intervals by a cage 2.

In this case, as shown in Figures 15 and 16, the cage 2 has two circular flanges 3a, 3b and multiple column sections 4 connecting the circular flanges 3a, 3b, and the needle rollers 1 are housed in pockets 5 formed between adjacent column sections.

JP 2007-46792 A

When the column portion 4 is disposed near the roller pitch circle P, the width dimension of the column portion 4 near the roller pitch circle P must be smaller than the distance between adjacent rollers in the circumferential direction. In contrast, as shown in Figure 14, the column portion 4 can be disposed on the outer diameter side of the roller pitch circle P to increase the width dimension of the column portion 4.

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 section will inevitably become smaller, resulting in a decrease in the strength of the column section.

In view of this situation, the present invention aims to provide a roller bearing and needle roller bearing that have a cross-sectional shape of the column portion of the retaining member that approximates a trapezoid, effectively utilizing the space between adjacent rollers to increase the cross-sectional area of the column portion, thereby improving strength, and increasing the number of rollers to improve the basic dynamic (static) load rating.

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

In the roller bearing of the present invention, the column-part opposing surfaces that face each other in the circumferential direction are inclined so that the pocket interior 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. In other words, 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. Furthermore, 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 account the allowable variation during processing.

It is preferable to set the plate thickness of the column portion (radial thickness of the column portion) to 10% to 30% of the roller diameter. By setting it in this way, the column portion is stable in terms of strength, and interference between the rollers and the retaining member can be effectively prevented.

It is preferable that the corners formed between the annular portion and the column of the holding member are curved portions with an R-shape. By setting it in this way, it is possible to reduce the stress generated in the column during processing.

The R-shape of the portion of the curved surface located on the outer diameter side can be set to be larger than the R-shape of the central portion, and the R-shape of the portion of the curved surface located on the inner diameter side can be set to be larger than the R-shape of the central portion. By setting them in this way, it is possible to effectively prevent the generated stress from becoming large. Here, a large R-shape means a large radius of curvature, which results in a longer distance of the curved surface from the annular portion to the column portion.

In order to improve the basic dynamic (static) load rating, it is preferable to increase the number of rollers and increase the packing ratio. Therefore, 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 the rollers adjacent in the circumferential direction may have a portion where they contact each other. Here, the roller packing ratio is the proportion of the rollers on the pitch circle, and is expressed as roller packing ratio = (number of rollers x roller diameter) / (pi x pitch circle diameter) .

The needle roller bearing of the present invention uses needle rollers for the rollers of the roller bearing. As a result, the cross-sectional area of the column portion of the needle roller bearing can be set relatively large, and a retaining member is used that allows the plate thickness of the column portion (radial thickness of the column portion) to be a thickness that provides stable strength. As a result, the number of rollers can be increased, and the basic dynamic (static) load rating of the bearing can be improved, and the strength of the bearing is stable.

The present invention makes it possible to increase the number of rollers, improving the basic dynamic (static) load rating, without reducing the strength of the column.

FIG. 2 is an enlarged perspective view of a main portion of a retaining member for a roller bearing according to the present invention. 1 is a simplified diagram of a roller bearing using a retaining member of the present invention. FIG. 4 is a cross-sectional view of a main part of a holding member. FIG. 11 is a cross-sectional view of a main portion of another holding member of the present invention. FIG. 4 is an enlarged plan view of a corner portion of the pocket. FIG. 4 is an enlarged perspective view of a corner of the pocket. 1 is a simplified diagram of a corner of a pocket. FIG. 4 is a perspective view of a main part showing a process of processing the holding member of the present invention. 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. An enlarged cross-sectional view of the main part showing the column portion after processing. 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. 12 is a cross-sectional view of a main part of the holding member shown in FIG. 11 . 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. FIG. 1 is a cross-sectional view of a conventional needle roller bearing. FIG. 1 is a cross-sectional view of a cage of a conventional needle roller bearing. FIG. 11 is an enlarged cross-sectional view of a main portion of a cage of a conventional needle roller bearing.

The following describes an embodiment of the present invention with reference to Figures 1 to 13. Figure 1 shows an enlarged perspective view of the essential parts of the retaining member of the roller bearing of the present invention. 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 to each other, and rollers 15 (see Figure 2) are housed in pockets 14 formed between adjacent pillar portions 13.

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 interior 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 the radial line L that passes through the center of the pocket.

The retaining member 10 is formed by pressing to produce a molded product S as shown in FIG. 8. In this case, the molded product S has annular portion components 11A, 12A and a plurality of column portion components 13A that connect the annular portion components 11A, 12A, and a pocket portion 14A is formed between adjacent column portion components 13A, 13A. In other words, the column portion facing surfaces that face each other along the circumferential direction of the column are not inclined surfaces 16a, 16b, but are end surfaces 17a, 17b that extend in the radial direction as shown in FIG. 9.

As a result, as shown in Figure 10, the end faces 17a, 17b are cut by cutting or other processing to produce the inclined faces 16a, 16b. In Figure 10, the area indicated by the two-dot chain line indicates the removed portions 21a, 21b. In this case, the inclined faces 16a, 16b of the column portion 13 may be formed by pressing (surface pressing) processing.

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 traditionally been used for retainers, and the molding method may be injection molding, punching (pressing), cutting (machining), etc., depending on the material used.

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 sufficient. 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°, taking into account the allowable variation during processing (forming).

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, the inclination angles θ of the inclined surfaces 16a, 16b are listed in Table 1 for less than 15°, 15°, 20°, 30°, 40°, 50°, 60°, 65°, and more than 65°.

If the inclination angle θ (θ1) (θ2) is 65° or more, the cross-sectional area of the column portion 13 will be small and the difference between the pocket inner diameter width W1 and the pocket outer diameter width W2 will be too large, which may result in the column portion 13 being weak in strength. In this case, it is marked with an X in Table 1. Also, if θ (θ1) (θ2) is 15° or less, it will not be possible to effectively utilize the area H of the space 30 (the space shown by hatching in Figure 2) between adjacent rollers in the circumferential direction to increase the column portion cross-sectional area, which may result in the column portion 13 not being strong enough. In this case, it is marked with an X in Table 1. For this reason, it is preferable to set the inclination angle θ (θ1) (θ2) to 20° or more and 60° or less, as marked with an O in Table 1.

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 pillar portion) T of the retaining member 10 and the roller diameter (roller diameter) D are shown in Table 2 for T/D of less than 5%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, and 35% or more.

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 larger, which may prevent the basic dynamic (static) load rating from being improved. In addition, it will be necessary to reduce the circumferential width dimension of the retaining member, which may result in the column portion 13 not being able to maintain sufficient strength. In this case, it is marked with an X in Table 2. In addition, if T/D is 5% or less, it may result in the column portion 13 not being able to maintain sufficient strength. In this case, it is marked with an X in Table 2. For this reason, as marked with an O in Table 2, 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 Figure 2).

As shown in Fig. 5 and Fig. 6, the four corners between the annular portion 11 (12) and the column portion 13 are formed as R-shaped curved surface portions 22. In this case, as shown in Fig. 7,
The R-shape of the portion located on the outer diameter side is larger than that of the central portion, and the R-shape of the portion located on the inner diameter side is larger than that of the central portion. Here, a larger R-shape means a larger radius of curvature, and as a result, the distance of the curved portion 22 from the annular portion 11 (12) to the column portion 13 becomes longer. That is, the radius of curvature of the portion located on the outer diameter side (outer diameter side portion 22a) is set to be larger than that of the central portion (thickness direction central portion 22c). Also, the radius of curvature of the portion located on the inner diameter side (inner diameter side portion 22b) is set to be larger than that of the central portion (thickness direction central portion 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 thickness direction central portion 22c is R3, R1>R3 and R2>R3 are satisfied, and the stress generated when a load is applied to the column portion 13 can be reduced, thereby improving the strength of the holding member 10. In addition, for example, by setting R1≒R2 and 1.015<(R1≒R2)/R3<1.5, the stress generated when a load is applied to the column portion 13 can be reduced, thereby improving the strength of the holding member 10. 1.015<(R1≒R2)/R3<1.5 is the case where the rollers contact the radial central portion of the surfaces of the columns 14a and 14b. On the other hand, the rollers may be set closer to the inner diameter or outer diameter of the pillars 14a, 14b. In this case, the strength of the retaining member 10 can be improved by setting the relationship to approximately 0.6<R1/R3<1.5, 0.6<R2/R3<1.5.

In Figures 11 and 12, a roller interference prevention protrusion 25 that bulges into the pocket is provided at the middle of the short side 24 of the pocket 14 in the annular portion 11 (12). By providing this roller interference prevention protrusion 25, interference between the retaining member 10 and the roller 15 is effectively prevented.

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 the column opposing surfaces that face each other along the circumferential direction are inclined surfaces 16a, 16b so that the inside of the pocket expands, and the column cross-sectional shape is made to be a shape that approximates a trapezoid, and when the inclination angle of the inclined surfaces 16a, 16b is θ, it is 20°≦θ≦60°.

In the roller bearing of the present invention, the columnar cross-sectional area can be set relatively large even if the columnar opposing surfaces facing each other along the circumferential direction are inclined surfaces 16a and 16b so that the pocket inner side is expanded. In other words, the columnar 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 columnar opposing surfaces to 20°≦θ≦60°, the plate thickness (radial thickness of the columnar portion) of the columnar portion 13 can be set to a thickness that is stable in terms of strength. In other words, if θ exceeds 60°, the plate thickness (radial thickness of the columnar portion) of the columnar portion 13 may become too small, or the columnar 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 the lower limit at around 20°.

For this reason, the present invention makes it possible to increase the number of rollers and improve the basic dynamic (static) load rating without reducing the strength of the column section 13. In addition, it is preferable to set the plate thickness (radial thickness of the column section) T of the column section 13 to 10% to 30% of the roller diameter D. By setting it in this way, the column section 13 is stable in terms of strength.

It is preferable that the corners between the annular portion 11 (12) and the column portion 13 are R-shaped curved portions 22. By setting it in this way, it is possible to reduce the stress generated in the column portion 13 during processing.

In the curved surface portion 22, the R shape of the portion located on the outer diameter side is larger than the R shape of the central portion, and the R shape of the portion located on the inner diameter side is 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 to be larger than the radius of curvature of the central portion (thickness direction central portion 22c). Also, the radius of curvature of the portion located on the inner diameter side (inner diameter side portion 22b) is set to be larger than the radius of curvature of the central portion (thickness direction central portion 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 thickness direction central portion 22c is R3, R1>R3 and R2>R3 are satisfied, and the stress generated when a load is applied to the column portion 13 can be reduced, and the strength of the retaining member 10 can be improved. Also, for example, by setting R1 ≒ R2 and 1.015 < (R1 ≒ R2) / R3 < 1.5, the stress generated when a load is applied to the column portion 13 can be reduced, and the strength of the retaining member 10 can be improved. 1.015 < (R1 ≒ R2) / R3 < 1.5 is the case where the rollers contact the radial center of the surfaces of the columns 14a and 14b. On the other hand, the rollers may be set closer to the inner diameter or outer diameter of the columns 14a and 14b, in which case the strength of the retaining member 10 can be improved by setting the relationship to about 0.6 < R1 / R3 < 1.5, 0.6 < R2 / R3 < 1.5.

The rollers may face each other with a gap between them in the circumferential direction, or may have portions where the rollers contact each other in the circumferential direction.

The needle roller bearing of the present invention uses the retaining member 10. As a result, the cross-sectional area of the column portion can be set relatively large, and the retaining member 10 is used to make the plate thickness of the column portion 13 (the radial thickness of the column portion) a thickness that provides stable strength. This increases the number of rollers, improving the basic dynamic (static) load rating of the bearing, and providing stable strength.

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 in the circumferential direction, 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. Incidentally, roller bearings in which the retaining member is used are, for example, those used in general industrial machinery, but can be used in particular in those requiring space saving and high load capacity, for example, in automotive machine parts and robot mechanism parts.

The retaining members shown in Figures 1 to 4 are disposed on the outer diameter side of the roller pitch circle, so that they can be used as an outer ring guide type 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, so that they can be used as an inner ring guide type 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.

10: retaining member 11, 12: annular portion 13: column portion 14: pocket 15: rollers 16a, 16b: inclined surface 22: curved surface portion 22a: outer diameter side portion 22b: inner diameter side portion 22c: central portion in thickness direction

Claims (5)

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 . 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 portion located on the inner diameter side is set to be larger than the R-shape of a central portion . 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. A roller bearing according to claim 1, further comprising portions where adjacent rollers in the circumferential direction come into contact with each other. A needle roller bearing, characterized in that needle rollers are used as the rollers of the roller bearing according to any one of claims 1 to 4 .

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