Automatic self-aligning roller bearing

Abstract

To provide an automatic self-aligning roller bearing with a comb-shaped machined cage, which has sufficient strength, can restrain behaviors of a roller, can be easily processed, and can be inexpensively manufactured.SOLUTION: An automatic self-aligning roller bearing 1 comprises an outer ring 2, an inner ring 3, plural rollers 4 annularly arranged in two lines between the outer ring 2 and the inner ring 3, and a machined retainer 5 for retaining the plural rollers 4. The machine retainer 5 comprises an annular part 5a arranged between two lines of rollers, and plural column parts 5b projecting from both axial side faces of the annular part 5a. A pocket P for rollably holding each roller is formed by the column parts adjacent to each other in a circumferential direction of the plural column parts 5b, and the pocket P has a pocket bottom part connected to the annular part and positioned at a root side of the column part, and a pocket inlet part extending from an axial tip edge of the pocket bottom part to a tip of the column part. The pocket bottom part has a partial conical shape with a smaller diameter toward the root side of the column part from the axial tip edge, and the pocket inlet part has a partial cylindrical shape.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] In a spherical roller bearing, a cage that holds the rollers is used that is shaped like a comb or a squirrel cage, and various shapes of each have been proposed (Patent Documents 1 and 2).

[0003] The roller bearing cage shown in Patent Document 1 is a comb-shaped machined cage consisting of an annular portion and multiple pillar portions protruding from the annular portion, and the rollers are held in pocket portions formed by the pillar portions adjacent in the circumferential direction. As shown in Fig. 8, this pocket portion is formed by machining so that the shape of the side surface 104d of the pillar portion 104b has a concave partial cylindrical surface, and the inner shape of the pocket portion p is cylindrical up to the base portion of the pillar portion 104b.

[0004] The self-aligning roller bearing shown in Patent Document 2 has spherical rollers as rolling elements, and as shown in Figure 9, the inner shape of pocket P in retainer 214 that holds the spherical rollers is a concave shape that follows the rolling surface of the spherical rollers. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2008-069868 A [Patent Document 2] JP 2018-169044 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in a comb cage, if the side shapes 104d, 214c, 214d of the circumferentially adjacent pillars 104b, 214b that form each pocket are cylindrically concave from the tip to the base of the pillars, the cross-sectional area (hereinafter sometimes simply referred to as the "cross-sectional area") along the circumferential direction of the bases 113, 214d becomes small, making it impossible to ensure sufficient strength of the pillars. Furthermore, the gap between the rollers held in the pockets p, P and the pillars 104b, 214b becomes large, making it impossible to sufficiently suppress the behavior of the rollers, resulting in an issue of unstable position and posture of the rollers.

[0007] Furthermore, if the inner surface shape of the pockets p, P that hold the rollers is a concave shape that follows the outer diameter surface of the spherical roller, the cross-sectional area of ​​the roots 113, 214d of the column parts 104b, 214b of the cage 104, 214 will be increased, and the strength can be increased. At the same time, the gap between the column parts 104b, 214b and the rollers will be uniform along the axial direction of the pocket, so the behavior of the rollers can be suppressed. However, when such a structure is adopted, the shape of the drill for machining the pockets p, P needs to be a spherical shape that follows the outer diameter of the roller. This poses the problem that it takes time to mold the tool, and the manufacturing cost of the cage is high.

[0008] An object of the present invention is to provide a self-aligning roller bearing which can suppress the behavior of the rollers while ensuring the strength of the cage post portions and can reduce manufacturing costs. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides a self-aligning roller bearing comprising an outer ring, an inner ring, a plurality of rollers arranged in two annular rows between the outer ring and the inner ring, and a machined cage for holding the plurality of rollers. The machined cage is a comb-shaped machined cage including an annular portion arranged between the two rows of rollers and a plurality of pillar portions protruding from axial side surfaces on both sides of the annular portion. A pocket for holding each roller so that it can roll is formed by circumferentially adjacent pillar portions of the plurality of pillar portions. The pocket has a pocket bottom portion connected to the annular portion and located on the base side of the pillar portions, and a pocket inlet portion extending from the axial tip edge of the pocket bottom to the tip of the pillar portions, the pocket bottom portion being a partial conical shape whose diameter decreases from the axial tip edge toward the base side of the pillar portions, and the pocket inlet portion being a partial cylindrical shape.

[0010] According to this configuration, the cross-sectional area of ​​the base of the bar of the cage can be made larger than the cross-sectional area of ​​the tip of the bar, so the strength of the cage can be improved compared to cages of a conventional structure in which the cross-sectional area of ​​the base of the bar is smaller. Furthermore, when the rollers are skewed, the base of the bar of the cage comes into contact with the outer diameter of the roller, so the behavior of the roller can be suppressed. In addition, since the shape of the pocket is a simple shape without an R shape, it is relatively easy to mold the drill for machining the pocket, so the cage can be manufactured inexpensively.

[0011] In the self-aligning roller bearing of the present invention, the axial length of the pocket bottom may be 20 to 40% of the axial length of the roller.

[0012] With this configuration, when the bearing rotates, the roots of the columns of the cage that form the pocket bottom do not come into contact with the maximum diameter parts of the rollers, and no force is generated that tilts the rotation axis of the cage relative to the cage, so the positional relationship between the cage and the rollers is maintained in a good condition, making it possible to suppress the behavior of the rollers. If the axial length of the pocket bottom exceeds 40% of the axial length of the rollers, the maximum diameter parts of the rollers may come into contact with the partial cone surface of the partial cone shape during rotation of the bearing, and a force that tilts the rotation axis of the cage may be applied. If the axial length of the pocket bottom is less than 20% of the axial length of the rollers, the necessary and sufficient cross-sectional area of ​​the roots of the columns cannot be ensured, which may cause strength problems.

[0013] In the self-aligning roller bearing of the present invention, the angle of the slope of the partial conical surface may be the angle of the tangent of the rolling surface of the roller relative to the roller axis at an axial position that is 10 to 30% of the axial length of the roller from the axial base edge of the pocket bottom.

[0014] With this configuration, when the rollers come into contact with the roots of the bars of the cage, they do so at an appropriate skew angle, making it possible to adequately control the behavior of the rollers, and since the roots of the bars of the cage are less likely to come into contact with the edge between the outer diameter surface of the roller and the chamfer on the end face side, it is possible to reduce wear at the roots of the bars of the cage. If the skew angle exceeds 30% of the axial length of the rollers, the skew angle when the rollers come into contact with the partial conical surface becomes undesirably large, reducing the effect of controlling the behavior of the rollers. If the skew angle falls below 10% of the axial length of the rollers, the edge between the outer diameter surface of the roller and the chamfer on the end face side is more likely to come into contact, raising concerns about wear at the partial conical surface. Effect of the Invention

[0015] In the self-aligning roller bearing of the present invention, the pocket bottom of the comb-shaped machined cage has a partially conical shape that decreases in diameter from the axial tip edge toward the base of the column, and the pocket inlet is partially cylindrical, which ensures the strength of the cage column, while suppressing roller behavior and reducing manufacturing costs. [Brief description of the drawings]

[0016] [Figure 1] 1 is a vertical sectional view of a self-aligning roller bearing according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] 5 is a cross-sectional view (corresponding to FIG. 2) of a main part of a self-aligning roller bearing according to a second embodiment of the present invention. [Figure 4] FIG. 11 is a cross-sectional view of a main portion of a self-aligning roller bearing according to a third embodiment of the present invention. [Diagram 5] FIG. 11 is a vertical sectional view of a self-aligning roller bearing according to a fourth embodiment of the present invention. [Figure 6] FIG. 11 is a vertical sectional view of a self-aligning roller bearing according to a fifth embodiment of the present invention. [Figure 7] 7 is a cross-sectional view taken along line VII-VII in FIG. 6. [Figure 8] 1A, 1B, and 1C are diagrams showing an example of a conventional roller bearing cage, in which (a) is an enlarged front view of a main portion, (b) is a plan view of the same, and (c) is a left side view of the same. [Figure 9] 1A and 1B are diagrams showing an example of a conventional retainer for a self-aligning roller bearing, in which (a) is a plan view and (b) is a BB cross-sectional view of (a). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] [First embodiment] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figs. 1 and 2 are views showing a first embodiment of a spherical roller bearing of the present invention. As shown in Fig. 1, the spherical roller bearing 1 comprises an outer ring 2, an inner ring 3, a plurality of rollers 4, and a cage 5. The plurality of rollers 4 are arranged in two rows between the inner and outer rings 3, 2, and the cage 5 holds the two rows of rollers 4, 4. Grease, for example, is filled in the bearing space between the inner and outer rings 3, 2. In this specification, the spherical roller bearing 1 may be simply referred to as a "bearing".

[0018] The outer ring 2 has a concave spherical raceway 2a formed on its inner diameter surface, and the inner ring 3 has two rows of concave spherical raceway surfaces 3a, 3a formed on its outer diameter surface. The inner ring 3 has a flange 6, 6 that bulges outward in the axial direction on its outer side. The two rows of rollers 4, 4 are provided between the raceway surface 2a of the outer ring 2 and the raceway surface 3a, 3a of the inner ring 3. The rollers 4 in each row are so-called barrel-shaped rollers whose rolling surfaces bulge outwardly in a spherical shape. The subassembly including the inner ring 3, the cage 5, and the two rows of rollers 4, 4 is configured to be capable of aligning relative to the outer ring 2. The self-aligning roller bearing 1 is one of so-called radial roller bearings in which the outer ring 2 is disposed radially outward from the outer peripheral surface of the inner ring 3. The axial direction of the central axis of the inner ring 3 and the outer ring 2 is defined as the "axial direction". The direction perpendicular to the "axial direction" is defined as the "radial direction".

[0019] <Cage> As shown in FIG. 2, the cage 5 is a comb cage including an annular portion 5a and pillar portions 5b protruding from both side surfaces of the annular portion 5a in the axially outward direction. The pillar portions 5b, 5b adjacent to each other in the circumferential direction form a pocket P, which is a space for holding the rollers 4. The pockets P are provided in two rows at equal circumferential intervals on both the left and right sides of the annular portion 5a, and each pocket P holds each of the rollers 4 in the two rows. The pockets P in each row may be formed in a staggered manner with a circumferential phase shift by arranging the pillar portions 5b of the cage 5 alternately on both sides protruding from the annular portion 5a with a circumferential phase shift. This arrangement can prevent load concentration at the same circumferential phase positions of the annular portion 5a.

[0020] 1, the outer diameter surface 5bc of the column portion 5b may be shaped so that the outer diameter becomes smaller toward the outside in the rotation axis direction of the cage 5. With this configuration, the rollers can be guided approximately along the vicinity of the radial middle between the outer diameter surface 5bc of the column portion 5b and the inner diameter surface 5bd consisting of an annular surface, so that the force acting on the column portion 5b due to contact with the rollers 4 can be received near the radial center of the column portion 5b. This improves the rigidity of the column portion 5b.

[0021] 1, the pillar portions 5b of the cage 5 may have a length exceeding 50% of the axial length of the rollers 4. As a result, when the rollers 4 are held in the pocket P, the tips of the pillar portions 5b of the cage 5 extend axially outward beyond the maximum diameter position of the rollers 4, and by holding the rollers across the maximum diameter of the rollers 4, the rollers 4 can be held more stably.

[0022] As shown in Fig. 2, the cage 5 is a machined cage in which each pocket P is machined by drilling, and is a rolling element guided cage guided by a plurality of rollers 4. The cage 5 is made of an iron-based material, a brass-based material, or a resin-based material.

[0023] <Pocket shape> The pocket P has a pocket bottom Pb connected to the annular portion 5a and located on the root side of the column portion 5b, and a pocket inlet Pa extending from the axial tip edge 7 of the pocket bottom Pb to the tip of the column portion 5b. The pocket inlet Pa has a partial cylindrical shape, and the pocket bottom Pb has a partial conical shape that becomes smaller in diameter from the axial tip edge 7 toward the root side of the column portion 5b. Since the pocket P is formed by the adjacent column portions 5b, 5b, the circumferential side of the column portion 5b has a shape corresponding to the pocket P. When the pocket P has the above shape, the circumferential side of the tip portion 5ba of the column portion 5b corresponding to the inlet portion of the pocket P is a concave partial cylindrical surface. The circumferential side of the base portion 5bb of the column portion 5b corresponding to the bottom of the pocket P is a concave partial conical surface.

[0024] <Action and effect> According to the self-aligning roller bearing shown in Figs. 1 and 2 described above, the machined comb cage 5 of the self-aligning roller bearing 1 includes an annular portion 5a disposed between the two rows of rollers 4, 4, and a plurality of columnar portions 5b protruding from the axial side surfaces on both sides of the annular portion. The columnar portions 5b, 5b adjacent to each other in the circumferential direction of the plurality of columnar portions 5b form a pocket P, which is a space for holding each roller 4 so that it can roll freely. The pocket P has a pocket bottom Pb connected to the annular portion 5a and located on the base side of the columnar portions 5b, and a pocket inlet portion Pa extending from the axial tip edge 7 of the pocket bottom Pb to the tip of the columnar portion 5b, and the pocket bottom Pb has a partially conical shape whose diameter decreases from the axial tip edge 7 toward the base side of the columnar portion 5b. This makes it possible to suppress the behavior of the rollers 4 while ensuring sufficient strength of the columnar portions 5b by making the cross-sectional area of ​​the base portion of the cage 5 larger than the cross-sectional area of ​​the tip portion of the columnar portion 5b. Furthermore, since the shape of the pocket P that holds the rollers 4 in the retainer 5 is a simple shape that is easier to process than a spherical shape, the shape of the drill used to machine the retainer 5 is a relatively easy shape to form, and the retainer can be manufactured more cheaply.

[0025] <Other embodiments> [Second embodiment] A second embodiment of the present invention is shown in Fig. 3. Fig. 3 is a cross-sectional view of a machined comb cage provided in a spherical roller bearing of the present invention, corresponding to Fig. 2. In this embodiment, the axial length L1 of the pocket bottom Pb is in the range of 20% to 40% of the roller length L of the roller 4 held in the pocket P.

[0026] The strength of the columnar portions 5b protruding from the annular portion 5a of the cage 5 is related to the axial length L1 of the pocket bottom Pb having a partially conical shape in the pocket P. As the axial length L1 of the pocket bottom Pb becomes longer, the columnar portions 5b of the cage 5 become thicker in the circumferential direction, increasing the rigidity, and the cross-sectional area of ​​the base portion of the columnar portions 5b connecting to the annular portion 5a increases, improving the strength of the columnar portions 5b. On the other hand, when the axial length L1 of the pocket bottom Pb approaches 50% of the roller length L of the rollers held in the pocket P, the maximum diameter portion of the roller 4 comes into contact with the columnar portions 5b of the cage 5 during rotation of the bearing. In this case, a force is applied in a direction that tilts the rotation axis of the cage 5, so that the behavior of the rollers 4 in the pocket P cannot be sufficiently suppressed and the strength of the columnar portions 5b is reduced.

[0027] The axial length L1 of the partially conical bottom Pb of the pocket P was changed to study its relationship with the strength of the bar portion, yielding the results shown in Table 1. The values ​​in the "Pocket bottom length" column in the table represent the ratio of the axial length L1 of the pocket bottom Pb to the roller length L of the retained roller. In the column strength column in the table, the symbol "◯" indicates that the bar portion of the cage has sufficient strength, the symbol "△" indicates that the bar portion of the cage has no strength problems, and the symbol "×" indicates that the bar portion of the cage has strength problems.

[0028] [Table 1]

[0029] Taking the above into consideration, it has been determined that, in the machined comb cage provided in the spherical roller bearing of this invention, the axial length L1 of the bottom of the pocket P is preferably in the range of 20% to 40% of the length L of the rollers 4 retained in the pocket P. In this way, by determining the axial length L1 of the pocket bottom Pb having a partial conical shape in the pocket P of the cage 5 to be within an appropriate numerical range, the strength of the column portions 5b of the cage 5 can be ensured and the behavior of the rollers 4 retained in the pocket P of the cage 5 can be sufficiently suppressed.

[0030] [Third embodiment] A third embodiment of the present invention is shown in Figure 4. In the self-aligning roller bearing of the present invention, the angle of the slope of the partial conical surface of pocket bottom Pb is the angle of the tangent direction of the rolling surface of roller 4 held in pocket P with respect to the roller axis, at an axial position that is 10% to 30% of the axial length of the roller from the axial base edge 8 of pocket bottom Pb.

[0031] Whether the behavior of the rollers 4 held in the pocket P of the cage 5 is suppressed depends on the relationship between the shape of the rollers 4 and the cone slope angle of the partial conical surface Pb at the bottom of the pocket P. The results of examining this relationship are shown in Table 2. In the table, a value of, for example, 10% in the "Tangent position" column indicates that the slope angle of the partial conical surface at the pocket bottom is equal to the tangent angle of the rolling surface of the rollers 4 held in the pocket P at a position of axial length L2 that is 10% of the roller length L from the axial base edge 8 of the pocket bottom Pb. In the column for roller behavior suppression effect in the table, the symbol "◯" indicates that the behavior of the rollers 4 is sufficiently suppressed by the cage 5, the symbol "△" indicates that there is no problem with suppressing the roller behavior, and the symbol "×" indicates that there is a problem with suppressing the roller behavior.

[0032] [Table 2]

[0033] Taking the above into consideration, it has been found that in the comb-type machined retainer provided in the self-aligning roller bearing of the present invention, it is preferable that the cone inclination angle of the partial conical surface at the bottom of pocket P be the angle of the tangent to the rolling surface of roller 4 relative to the axial direction of roller 4 at a position that is 10% or more and 30% or less of the roller length L of roller 4 held in pocket P. In this manner, by determining the cone inclination angle of the partial conical surface of pocket P of cage 5 to be within an appropriate numerical range, the behavior of rollers 4 retained in pocket P of cage 5 can be sufficiently suppressed.

[0034] [Fourth embodiment] A fourth embodiment of the present invention is shown in Figure 5. Figure 5 is a longitudinal sectional view of a self-aligning roller bearing. In a machined comb cage, the outer diameter of the annular portion 5a of the cage 5 is made larger than the outer diameter of the columnar portions 5b of the cage 5, so that the cage 5 rotates in sliding contact with the inner peripheral surface of the outer ring 2, forming an outer ring guide type cage. This makes it possible to guide the rollers while sufficiently suppressing their behavior even in an environment where the outer ring rotates or is subjected to vibration.

[0035] [Fifth embodiment] 6 and 7 show a fifth embodiment of the present invention. In the comb machined cage, as shown in FIG. 6, separate comb machined cages 5L and 5R are provided for the left and right roller rows CL and CR. FIG. 7 shows a cross-sectional view of the comb machined cage 5R taken along line VII-VII in FIG. 6. A pocket P is formed by a plurality of pillars 5Rb protruding from the annular portion 5Ra of the comb machined cage 5R, and the rollers 4 are held in this pocket P. The same is true for the other comb machined cage 5L. As a result, even if a load is applied to the rollers in one row, causing a difference in the revolution speed of the left and right roller rows CL and CR, the cages 5L and 5R for the left and right roller rows CL and CR can rotate independently, so that contact between the rollers 4 and the cages 5L and 5R caused by the difference in the revolution speed of the left and right roller rows CL and CR is unlikely to occur, and the occurrence of abnormalities and wear of the cage due to contact can be reduced.

[0036] Although the present invention has been described above based on the embodiments, the embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is indicated by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0037] Reference Signs List 1... self-aligning roller bearing, 2... outer ring, 3... inner ring, 4... roller, 5... cage, 5a... annular portion, 5b... column portion, 7... axial tip edge, 8... axial base edge, P... pocket, Pa... pocket inlet portion, Pb... pocket bottom

Claims

1. A self-aligning roller bearing comprising an outer ring, an inner ring, a plurality of rollers arranged in two rows annularly between the outer ring and the inner ring, and a machined cage for retaining the plurality of rollers, The machined cage is a comb-shaped machined cage including an annular portion disposed between the two rows of rollers and a plurality of column portions protruding from axial side surfaces on both sides of the annular portion, and pockets for holding each roller in a freely rolling manner are formed by adjacent column portions in the circumferential direction of the plurality of column portions, The pocket has a pocket bottom portion connected to the annular portion and located on the base side of the column portion, and a pocket inlet portion extending from an axial tip edge of the pocket bottom portion to a tip of the column portion, a pocket bottom having a partial conical shape that decreases in diameter from the axial tip edge toward the base side of the column portion, and a pocket inlet having a partial cylindrical shape.

2. 2. The spherical roller bearing according to claim 1, A self-aligning roller bearing, wherein the axial length of the pocket bottom is 20 to 40% of the axial length of the roller.

3. The self-aligning roller bearing according to claim 1 or 2, a slope angle of the partial cone surface of the partial cone shape is an angle of a tangent of the rolling surface of the roller with respect to the roller axis at an axial position that is 10 to 30% of the axial length of the roller from the axial base edge of the pocket bottom.

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