JP7627637B2 - Roller and needle roller bearings - Google Patents

Description

The present invention relates to roller bearings and needle rollers.

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.

That is, as shown in FIG. 15, the cage 2 has two circular flanges 3a, 3b and a number of columns 4 connecting the circular flanges 3a, 3b, and the needle rollers 1 are housed in pockets 5 formed between adjacent columns.

JP 2007-46792 A

When the bar section 4 is disposed near the roller PCD (roller pitch circle P), the width dimension of the bar section 4 near the roller pitch circle P must be smaller than the distance between adjacent rollers in the circumferential direction. In contrast, by disposing the cage bar section 4 on the outer diameter side of the roller PCD (roller pitch circle P), the width dimension of the bar section 4 can be made larger, and it is also possible to use a larger number of rollers than in conventional products.

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 4 will inevitably become smaller, as shown in Figure 16, resulting in a decrease in the strength of the column portion 4.

In view of this situation, the present invention aims to provide a roller bearing and needle roller bearing that improve the basic dynamic (static) load rating by increasing the number of rollers, by making the cross-sectional shape of the column part of the retaining member approximately trapezoidal, and by making effective use of the space between adjacent rollers, increase the cross-sectional area of the column part and suppress a decrease in strength.

The roller bearing of the present invention 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, and has a retaining member in which the rollers are retained in pockets formed between adjacent column portions, and the retaining member has column portion opposing surfaces opposing each other in the circumferential direction that are inclined so that the inside of the pocket expands, the roller filling rate on the pitch circle of the rollers is 93% or more and less than 100%, and when the circumferential length of the column portions on the contact pitch circle between the rollers and the column portions of the retaining member at a corresponding portion of the final clearance formed between circumferentially adjacent rollers on the pitch circle is B, the dimension between adjacent rollers in the circumferential direction is A and the dimension of the final clearance is rs, then A > (B + rs), and when the circumferential length of the column portions on the contact pitch circle at a portion where adjacent rollers in the circumferential direction come into contact is D and the dimension between adjacent rollers in the circumferential direction is C, then C > D. Here, the roller packing ratio is the ratio of the rollers to the pitch circle, and is expressed as: Roller packing ratio = (number of rollers x roller diameter) / (pi x pitch circle diameter) . Here, the final clearance is the clearance that ultimately occurs between the last roller and the first roller when adjacent rollers are assembled so as to be in contact with each other in the circumferential direction.

In the roller bearing of the present invention, the opposing surfaces of the columns facing each other in the circumferential direction are inclined so that they expand toward the inside of the pocket, so that the cross-sectional area of the columns can be set relatively large even if they are arranged on the outer diameter side or the inner diameter side of the roller pitch circle. Generally, if the pocket clearance is made larger than the final clearance, the circumferential width dimension of the columns becomes smaller, and even if the specifications are such that the load on the columns is reduced, the retaining member may not be able to withstand the load. However, by making A>(B+rs) and C>D, the space provided between adjacent rollers in the circumferential direction (the space on the outer diameter side of the roller pitch circle and the space on the inner diameter side of the roller pitch circle) can be effectively used to make the cross-sectional area of the columns as large as possible. Moreover, it is possible to arrange the rollers to the same extent as in the so-called full roller state, where there are parts that contact adjacent rollers in the circumferential direction.

It is preferable that the cross-sectional area of the bar portion on the side corresponding to one of the spatial areas on the outer diameter side or inner diameter side of the pitch circle between adjacent rollers in the circumferential direction is 25% to 50%. By setting it in this way, the cross-sectional area of the bar portion is stabilized in terms of strength, and contact between the bar portion and the roller can be effectively suppressed. In other words, if the cross-sectional area exceeds 50%, the pocket clearance will be smaller than the final clearance, and the roller and the bar portion will strongly interfere with each other. Note that the space area between the rollers can be on the outer diameter side of the roller pitch circle or on the inner diameter side of the roller pitch circle.

The spatial area may be on the outer diameter side of the pitch circle, and the column portion may be formed only on the outer diameter side of the pitch circle. 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 roller and the retaining member can be effectively prevented.

Can be used with the outer ring guide system. Here, outer ring guide means that the holding member is positioned by abutting it against the outer ring, and the outer surface acts as a guide surface and abuts against the inner circumference of the outer ring.

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 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. This increases the number of rollers, improving the basic dynamic (static) load rating of the bearing, and providing stable strength.

This 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 a simplified perspective view of a retaining member of the present invention. FIG. 1 is a simplified diagram of a portion where a final clearance is provided. 1 is a simplified diagram showing a portion where rollers are in contact with each other. FIG. 4 is a cross-sectional view of a portion where rollers are in contact with each other. 4 is a simplified diagram showing inter-roller spaces generated between adjacent rollers in the circumferential direction. FIG. 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. 13 is an enlarged cross-sectional view of a main portion showing the post portion of the holding member after machining. FIG. 13 is a simplified diagram of a portion where a final clearance is provided of another retaining member of the present invention. FIG. 13 is a simplified diagram of a portion where rollers of another retaining member of the present invention are in contact with each other. 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 for roller bearings 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 Figures 2 to 4, the opposing surfaces of the columns facing each other in the circumferential direction are inclined surfaces 16a, 16b so that the pocket interior side expands, i.e., so that the pocket expands from the outer diameter to the inner diameter side. Therefore, the cross-sectional shape of the column 13 is a shape that approximates a trapezoid. In addition, the retaining member 10 is positioned on the outer diameter side of the roller pitch circle P1.

The retaining member 10 is formed by pressing to produce a molded product S as shown in FIG. 9. 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 opposing 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 radially, as shown in FIG. 10.

As a result, as shown in Figure 11, the end faces 17a, 17b are cut by cutting or other processing to produce the inclined faces 16a, 16b. In Figure 11, the area indicated by the two-dot chain line indicates the removed parts 21a, 21b. The inclined faces 16a, 16b of the column part 13 may also 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.

At a portion corresponding to the final clearance G formed between circumferentially adjacent rollers on the roller pitch circle P1, the circumferential length of the column portion 13 on the contact pitch circle P2 between the roller and the column portion 13 is B, the dimension between adjacent rollers in the circumferential direction is A, and the dimension of the final clearance is rs, then A > (B + rs). Also, at a portion where adjacent rollers 15 contact each other in the circumferential direction, the circumferential length of the column portion 13 on the contact pitch circle P2 is D, and the dimension between adjacent rollers in the circumferential direction is C, then C > D. Here, the final clearance is the clearance that ultimately occurs between the last roller 15 and the first roller 15 when the rollers 15, 15 adjacent to each other in the circumferential direction are assembled so that they are in contact with each other.

The cross-sectional area of the pillar portion 13 between adjacent rollers in the circumferential direction is set to 25% to 50% of the area of the space 30 between adjacent rollers in the circumferential direction. Here, the space 30 is the space shown by cross-hatching in FIG. 5, and in this case, is the range on the outer diameter side of the roller pitch circle between adjacent rollers in the circumferential direction. The pillar portion 13 corresponding to the area of the space 30 is also provided on the outer diameter side of the pitch circle, and corresponds to its cross-sectional area. If the pillar portion 13 is provided on the inner diameter side of the pitch circle, the space 30 is also within the range on the inner diameter side. It is preferable that the radial thickness of the pillar portion 13 is 10% to 30% of the roller diameter.

Next, with respect to the retaining member 10 shown in FIG. 1 , the preferred ratio of the cross-sectional area of the pillar portion 13 to the area of the space 30 between adjacent rollers in the circumferential direction is shown in Table 1 for S1/H (%) less than 20%, 20%, 25%, 30%, 40%, 50%, 55%, and more than 55%, where H is the area of the space 30 between adjacent rollers and S1 is the cross-sectional area of the pillar portion 13.

If it is 55% or more, there is a risk of relatively strong interference between the rollers and the bar portion. In this case, it is marked with an X in Table 1. If it is 20% or less, there is a risk of poor roller retention. In this case, it is marked with an X in Table 1. For this reason, it is preferable to set the cross-sectional area of the bar portion 13 between adjacent rollers in the circumferential direction, marked with an O in Table 1, to 25% to 50% of the spatial area between adjacent rollers in the circumferential direction.

Next, with respect to the retaining member 10 shown in FIG. 1 , preferred 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 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 indicated by 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 indicated by an X in Table 2. For this reason, as indicated by 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. 6 and Fig. 7, 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. 8,
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 the above embodiment, the retaining member 10 is disposed on the outer diameter side of the roller pitch circle P1, but as shown in Figures 12 and 13, the retaining member 10 may be disposed on the inner diameter side of the roller pitch circle P1. In this case, the pocket 14 is expanded from the inner diameter side to the outer diameter side, and the columnar opposing surfaces facing each other along the circumferential direction are inclined surfaces 16a and 16b so that the inside of the pocket is expanded, and the columnar cross-sectional shape is made to be a shape that approximates a trapezoid. Then, when the circumferential length of the columnar portion 13 on the contact pitch circle P2 between the roller and the columnar portion 13 at the corresponding portion of the final gap G formed between adjacent rollers in the circumferential direction on the roller pitch circle P1 is B, the dimension between adjacent rollers along the circumferential direction is A, and the gap dimension of the final gap G is rs, A>(B+rs). In addition, the circumferential length of the column portion 13 on the contact pitch circle P2 at the location where adjacent rollers 15 contact each other in the circumferential direction is D, and the distance between adjacent rollers in the circumferential direction is C, so that C>D.

The cross-sectional area of the column portion 22 between adjacent rollers in the circumferential direction is set to 25% to 50% of the area of the space 30 between adjacent rollers in the circumferential direction. Here, this is the range between the space 30 and the inner diameter side of the roller pitch circle between adjacent rollers in the circumferential direction. It is preferable that the radial thickness of the column portion 13 is 10% to 30% of the roller diameter D1.

In the roller bearing of the present invention, the column section cross-sectional area can be set relatively large even if the column section is disposed on the outer diameter side or the inner diameter side of the roller pitch circle P1 by making the column section opposing surfaces that face each other in the circumferential direction inclined surfaces 16a, 16b so that the pocket inner side is expanded. Generally, if the pocket clearance is made larger than the final clearance, the column section circumferential width dimension becomes small, and even if the specification is such that the load on the column section 13 is reduced, the retaining member may not be able to withstand the load. However, by making A>(B+rs) and C>D, the space provided between adjacent rollers in the circumferential direction (the space on the outer diameter side of the roller pitch circle P1 and the space on the inner diameter side of the roller pitch circle P1) can be effectively used to make the column section cross-sectional area as large as possible. Moreover, it is possible to arrange the rollers 15 to the same extent as the so-called full roller state, in which there are parts that contact the adjacent rollers 15, 15 in the circumferential direction.

As a result, 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.

In the bearing shown in Figures 2 and 3, the retaining member 10 is disposed on the outer diameter side of the roller pitch circle P1, so that the roller bearing can be made to use an outer ring guide system. Here, outer ring guide means that the retaining member 10 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.

In addition, in the bearing shown in Figures 12 and 13, the retaining member 10 is disposed on the inner diameter side of the pitch circle, so that the roller bearing can be made to have an inner ring guide system. Here, inner ring guide means that the retaining member 10 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.

It is preferable that the corners between the annular portion 11 (12) and the column portion 13 are formed into curved portions 22. By setting them 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 needle roller bearing of the present invention uses the retaining member 10. As a result, this needle roller bearing can set the cross-sectional area of the column portion relatively large, and uses a retaining member that allows the plate thickness of the column portion 13 (the radial thickness of the column portion) to be a thickness that provides stable strength, and by increasing the number of rollers, the bearing can improve its basic dynamic (static) load rating and also provide a 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.

10: retaining member 11, 12: annular portion 13: column portion 14: pocket 15: roller 16a: inclined surface 16a: inclined surface P1: pitch circle P2: contact pitch circle

Claims (7)

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,
a roller bearing comprising: said retaining member having inclined surfaces facing column portions opposed in the circumferential direction so that the inside of the pocket expands; a roller filling rate on the pitch circle of the rollers is 93% or more and less than 100%; a circumferential length of the column portions on a contact pitch circle between the rollers and the column portions of the retaining member at a corresponding portion of an ultimate clearance formed between circumferentially adjacent rollers on the pitch circle is B, a dimension between adjacent rollers in the circumferential direction is A, and a dimension of the ultimate clearance is rs, where A > (B + rs); a circumferential length of the column portions on a contact pitch circle between the rollers and the column portions of the retaining member at a corresponding portion of an ultimate clearance formed between circumferentially adjacent rollers on the pitch circle is D, and a dimension between adjacent rollers in the circumferential direction is C, where C >D; a corner formed between the annular portion and the column portions of the retaining member is an R-shaped curved portion, and the R-shape of a portion of the curved portion located on 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,
a roller bearing comprising: said retaining member having inclined surfaces facing column portions opposed in the circumferential direction so that the inside of the pocket expands; a roller filling rate on the pitch circle of the rollers is 93% or more and less than 100%; a circumferential length of the column portions on a contact pitch circle between the rollers and the column portions of the retaining member at a corresponding portion of an ultimate clearance formed between circumferentially adjacent rollers on the pitch circle is B, a dimension between adjacent rollers in the circumferential direction is A, and a dimension of the ultimate clearance is rs, where A > (B + rs); a circumferential length of the column portions on a contact pitch circle between the rollers and the column portions of the retaining member at a corresponding portion of an ultimate clearance formed between circumferentially adjacent rollers on the pitch circle is D, and a dimension between adjacent rollers in the circumferential direction is C, where C >D; a corner formed between the annular portion and the column portions of the retaining member is an R-shaped curved portion, and the R-shape of a portion of the curved portion located on the inner diameter side is set to be larger than the R-shape of a central portion . A roller bearing according to claim 1 or claim 2, characterized in that the cross-sectional area of the column portion on the side corresponding to one of the spatial areas, either on the outer diameter side or the inner diameter side of the pitch circle between adjacent rollers in the circumferential direction, is 25% to 50 %. 4. A roller bearing according to claim 3, wherein the spatial area is on the outer diameter side of the pitch circle, and the pillar portion is formed only on the outer diameter side of the pitch circle. 5. A roller bearing according to claim 1, wherein the radial thickness of the column portion is 10% to 30% of the roller diameter. 6. A roller bearing according to claim 1, which is of an outer ring guide type. 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 6 .

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