tapered roller bearings

Abstract

To provide a conical roller bearing that suppresses the behavior of a conical roller using inexpensive means that does not require major changes of a structure of an iron plate holder and does not impair the ease of manufacturing an inner ring assembly, and is suitable for a use condition of lubrication with low-viscosity oil.SOLUTION: A column part of an iron plate holder has a shape in which an outer surface 43a of the column part is recessed. Based on the concave shape of the outer surface 43a, a gap between a conical roller and a small diameter side of the column part is made smaller than a gap between the conical roller and a large diameter side of the column part, so that the behavior of the conical rollers is suppressed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] BACKGROUND ART Conventionally, there is a tapered roller bearing in which a plurality of tapered rollers arranged between an inner ring and an outer ring are spaced apart in the circumferential direction by a steel plate cage.

[0003] Steel plate cages for tapered roller bearings are generally made by punching a circular blank plate out of iron plate material, squeezing the circular blank plate into a cup shape with a conical peripheral wall and bottom plate, punching out the peripheral wall to form a pocket, and applying a surface pressing process to the column portion (for example, Patent Document 1).

[0004] Furthermore, the inner ring of a tapered roller bearing generally has a raceway surface, a large rib, and a small rib, all of which are integral with the cage. When a steel plate cage is used, the small-diameter side of the steel plate cage is generally subjected to plastic working, in which a die is used to press the small-diameter side of the steel plate cage to expand the diameter. With tapered rollers placed in each pocket of the expanded steel plate cage, the steel plate cage, each tapered roller, and the inner ring are assembled from the small-diameter side of the inner ring, and each tapered roller is positioned on the raceway surface of the inner ring. Then, the small-diameter side of the steel plate cage is pressed with a die to return the expanded diameter to its original state (crimping), thereby preventing the tapered rollers from falling out from between the small-diameter side annular portion of the cage and the small rib of the inner ring, and an inner ring assembly is constructed in which the cage, each tapered roller, and inner ring are assembled in an inseparable state (see, for example, Patent Document 2).

[0005] The guide surfaces of the column portions of the steel plate cage that come into contact with the tapered rollers are generally formed into a flat shape by subjecting the circumferential ends of the column portions to a face pressing process (for example, Patent Document 3).

[0006] A gap is set between the column portion and the tapered roller to provide radial and circumferential clearance for the pocket. The size of this gap determines the allowable range of movement of the tapered roller relative to the cage. The final size of this gap is determined by the aforementioned crimping process. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-293698 [Patent Document 2] JP 2017-26001 A [Patent Document 3] Patent No. 6786196 Summary of the Invention [Problem to be solved by the invention]

[0008] In recent years, in various devices such as automotive drive units (differentials, transmissions, EV reducers, HEV reducers, etc.) and industrial machinery devices (robot reducers, construction machinery, tractors, etc.), the viscosity of the oils used has been reduced at an accelerating pace to increase efficiency, making it more difficult to lubricate the rolling bearings installed inside them. It has become important to provide tapered roller bearings that are suitable for such harsh operating conditions.

[0009] With low-viscosity oil, it is difficult to maintain an adequate oil film at the sliding contact area between the large end face of the tapered roller and the large rib of the inner ring, and poor lubrication can increase the resistance at the sliding contact area mentioned above, raising concerns that the behavior of the tapered rollers (skew direction, tilt direction) may be disrupted. Other bearing operating conditions (amount of lubricant, load, rotational speed, temperature, operating time, foreign matter mixed in the lubricant, etc.) can also disrupt the behavior of the tapered rollers. If the behavior of the tapered rollers is significantly disrupted, there is a concern that the smooth rotation of the bearing may be hindered due to disruptions in the contact pressure at the rolling contact area between the raceway surfaces of the inner and outer rings and the rolling surfaces of the tapered rollers, and heat generation at the sliding contact area mentioned above.

[0010] In conventional steel plate cages in which the guide surface of the column portion is flat, as in Patent Document 2, there is a limit to the gap that can be set between the column portion and the tapered rollers, and it is not possible to constrain the tapered rollers enough to stabilize their behavior (skew direction, tilt direction), leaving room for improvement.

[0011] Therefore, the problem that this invention aims to solve is to suppress the behavior of the tapered rollers using an inexpensive means that does not require major changes to the structure of the steel plate cage used in tapered roller bearings and does not impair the ease of manufacturing the inner ring assembly. [Means for solving the problem]

[0012] In order to solve the above problems, the present invention provides a tapered roller bearing comprising an inner ring, an outer ring, a plurality of tapered rollers arranged between the inner ring and the outer ring, and an iron plate retainer that holds the plurality of tapered rollers, wherein the inner ring integrally has a raceway surface, a large rib, and a small rib, and the iron plate retainer integrally has a small diameter side annular portion, a large diameter side annular portion, and a plurality of pillar portions that separate the space between the small diameter side annular portion and the large diameter side annular portion into a plurality of pockets, and the pillar portions have outer surfaces that are continuous with the outer peripheries of the small diameter side annular portion and the large diameter side annular portion, and the pillar portions have a configuration in which the outer surface of the pillar portions is recessed so that the gap between the tapered rollers and the small diameter side of the pillar portions is smaller than the gap between the tapered rollers and the large diameter side of the pillar portions.

[0013] According to the above configuration, the gap between the small-diameter side of the bar portion and the tapered rollers is smaller than the gap between the large-diameter side of the bar portion and the tapered rollers, based on the recessed shape of the outer surface of the bar portion. Therefore, when the behavior of the tapered rollers becomes unstable under various bearing operating conditions, the bar portion can quickly absorb the tip end (small-diameter side) of the tapered roller due to the behavior, thereby suppressing the behavior of the tapered rollers. Furthermore, making the gap on the small-diameter side smaller than the gap on the large-diameter side is achieved by plastic deformation of the bar portion, which is a slight bending due to the recessed shape of the outer surface of the bar portion. This can be achieved by slightly changing the shape of the crimping die that determines the final gap when assembling the inner ring assembly. This eliminates the need for major structural changes to the steel plate cage, and allows the steel plate cage to have the ability to suppress the behavior of the tapered rollers using inexpensive means that do not impair the ease of manufacturing the inner ring assembly.

[0014] When the distance between an imaginary line tangent to the outer periphery of the small diameter side annular portion and the outer periphery of the large diameter side annular portion and the outer surface of the base portion is taken as the depth of the concave shape molded in the outer surface of the base portion, it is preferable that the deepest part having the greatest depth on the outer surface of the base portion is molded on the small diameter side of the base portion. In this way, the gap on the small diameter side can be made particularly small on the smaller diameter side of the base portion, i.e., closer to the runout tip of the tapered roller, and the behavior of the tapered roller can be more effectively suppressed.

[0015] It is more preferable that the depth of the deepest part is 10 μm or more and 200 μm or less. In this way, it is possible to improve the effect of suppressing the behavior of the tapered rollers, while preventing the gap on the small diameter side from becoming excessively small, so as not to hinder the smooth rotation of the tapered rollers.

[0016] When the outer diameter of the steel plate cage is φD, the inner diameter of the steel plate cage is φd, the length of the pocket is Lw, the distance between an imaginary line tangent to the outer periphery of the small diameter side annular portion and the outer periphery of the large diameter side annular portion and the outer periphery of the bar portion is the depth of the concave shape formed in the outer surface of the bar portion, the maximum depth in the outer surface of the bar portion is Dp, and (φD / φd)×(Lw / Dp)=cage coefficient, the steel plate cage preferably satisfies 100<cage coefficient<1300. In this way, the above-mentioned concave shape can be effectively imparted to the outer surface of the bar portion with appropriate rigidity according to the size of the steel plate cage.

[0017] It is preferable that the minimum value of the gap between the small diameter side of the base portion and the tapered roller is 0.01 mm or more and 0.12 mm or less, which makes it possible to avoid strong contact between the tapered roller and the base portion under normal conditions while realizing excellent performance in suppressing the behavior of the tapered roller. [Effects of the Invention]

[0018] As described above, by adopting the above configuration, the cage according to the present invention can suppress the behavior of the tapered rollers using an inexpensive means that does not require major changes to the structure of the steel plate cage used in tapered roller bearings and does not impair the ease of manufacturing the inner ring assembly. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is an exaggerated view showing the outer surface shape of a column portion of a tapered roller bearing according to an embodiment of the present invention. [Figure 2] 2 is a cross-sectional view of a tapered roller bearing according to the embodiment of FIG. 1; [Figure 3] Cross section of the steel cage in Figure 2 [Figure 4] Partially enlarged cross-sectional view of line IV-IV in Figure 2 [Figure 5] Enlarged cross-sectional view of the VV line in Figure 2 [Figure 6] A diagram illustrating the disturbance of the tapered roller behavior in Figure 2 [Figure 7] FIG. 2 is a diagram showing a first modification of the outer surface shape of the column portion according to the embodiment of FIG. 1; [Figure 8] FIG. 2 is a diagram showing a second modified example of the outer surface shape of the column portion according to the embodiment of FIG. 1; [Figure 9] FIG. 10 is a diagram showing a third modification of the outer surface shape of the column portion according to the embodiment of FIG. 1; DETAILED DESCRIPTION OF THE INVENTION

[0020] A tapered roller bearing according to an embodiment of the present invention is shown in FIGS. 1 to 3. FIG.

[0021] The tapered roller bearing shown in Figure 2 comprises an inner ring 10, an outer ring 20, a plurality of tapered rollers 30 arranged between the inner ring 10 and the outer ring 20, and an iron plate retainer 40 that holds these plurality of tapered rollers 30.

[0022] The inner ring 10 is composed of a raceway ring integrally having a raceway surface 11 formed in a conical shape on the outer periphery thereof, a large flange 12 formed to have a larger diameter than the large-diameter side edge of the raceway surface 11, and a small flange 13 formed to have a larger diameter than the small-diameter side edge of the raceway surface 11.

[0023] The large flange 12 of the inner ring 10 supports the large end faces of the tapered rollers 30, on whose rolling surfaces 31 a thrust force toward the larger diameter side in the axial direction acts during rotation of the bearing, and also guides them in the circumferential direction.

[0024] The small flange 13 of the inner ring 10 prevents the tapered rollers 30 from falling off the raceway surface 11 to the smaller diameter side, and is a part that forms an assembly of these tapered rollers 30, the steel plate retainer 40 and the inner ring 10.

[0025] The outer ring 20 is made of a raceway ring having a raceway surface 21 formed in a conical shape on the inner periphery side.

[0026] The tapered roller 30 is a rolling element having a rolling surface 31 formed in a conical shape.

[0027] A plurality of tapered rollers 30 are arranged in a single row between the inner ring 10 and the outer ring 20.

[0028] The steel plate cage 40 is an annular bearing component that holds the multiple tapered rollers 30 at a predetermined pitch in the circumferential direction. As described in the background art, the steel plate cage 40 is formed by plastic working such as drawing and pocket punching on a circular blank plate made of iron-based plate material, and is crimped when the inner ring 10, the multiple tapered rollers 30, and the steel plate cage 40 are assembled into an inner ring assembly.

[0029] 2 shows a state in which the center lines of the inner ring 10, outer ring 20, and steel plate cage 40 are aligned, and this center line will be referred to below as the "bearing center axis CL1." Fig. 2 also shows a positional relationship in which the center axes of the inner ring 10 and outer ring 20, which are aligned with the bearing center axis CL1, and the center axis CL2 of the tapered rollers 30 are included in the same imaginary axial plane, and the center axis CL2 of the tapered rollers 30 is directly opposed to a point on the bearing center axis CL1, which is the apex of the cone shape of the inner and outer raceway surfaces 11, 21. Hereinafter, the direction along the bearing center axis CL1 will be referred to as the "axial direction," the direction perpendicular to the bearing center axis CL1 will be referred to as the "radial direction," and the circumferential direction going around the bearing center axis CL1 will be referred to as the "circumferential direction."

[0030] 3, the steel plate cage 40 integrally includes a small-diameter side annular portion 41, a large-diameter side annular portion 42, and a plurality of pillar portions 43 extending between the small-diameter side annular portion 41 and the large-diameter side annular portion 42. The steel plate cage 40 has a shape that substantially has multiple rotational symmetries in the circumferential direction.

[0031] The small diameter side annular portion 41 has a circular outer periphery 41a extending in the circumferential direction. The large diameter side annular portion 42 has an outer periphery 42a that is larger in diameter than the outer periphery 41a of the small diameter side annular portion 41. The inner diameter φd of the iron plate retainer 40 matches the inner diameter of the small diameter side annular portion 41. The outer diameter φD of the iron plate retainer 40 matches the outer diameter of the large diameter side annular portion 42.

[0032] The plurality of pillar portions 43 are plate portions that divide the space between the small diameter side annular portion 41 and the large diameter side annular portion 42 into a plurality of pockets 44. The plurality of pillar portions 43 are arranged at equal intervals in the circumferential direction. Each pocket 44 is a space that accommodates one tapered roller 30.

[0033] The column portion 43 has an outer surface 43 a located on the outer periphery of the steel plate cage 40 , an inner surface 43 b located on the inner periphery of the steel plate cage 40 , and a guide surface 43 c that comes into contact with the tapered rollers 30 .

[0034] The guide surfaces 43c of the column portions 43 are formed on both circumferential ends of each column portion 43. During plastic working of the steel plate cage 40, the guide surfaces 43c are pressed into a flat surface. In other words, the guide surfaces 43c are flat before the start of assembling the inner ring assembly.

[0035] FIG. 1 shows the shape of the outer surface 43a of the bar portion 43. The shape of the outer surface 43a shown in FIG. 1 corresponds to the shape of the generatrix of the outer surface 43a. The shape shown in FIG. 1 is substantially continuous across the entire circumferential width of the outer surface 43a. The dashed dotted line Pc in FIG. 1 is an imaginary line indicating an imaginary plane that is the boundary between the small diameter side and large diameter side of the bar portion 43. That is, the imaginary line Pc indicates the center position that bisects the length of the bar portion 43 in FIG. 1. The length of the bar portion 43 coincides with the length Lw of the pocket 44 shown in FIG. 2. The length Lw of the pocket 44 corresponds to the distance between an imaginary plane tangent to the surface portion of the small diameter side annular portion 41 facing the pocket 44 and an imaginary plane tangent to the surface portion of the large diameter side annular portion 42 facing the pocket 44. The direction of the imaginary line Pc shown in FIG. 1 is perpendicular to the center axis CL2 of the tapered roller 30 in the normal state shown in FIG. 2. In addition, in order to exaggerate the shape of the outer surface 43a in Figure 1, the shape of the outer surface 43a shown in Figure 1 has a significantly changed aspect ratio in the direction in which the imaginary line Pc extends and in the direction perpendicular to the imaginary line Pc, compared to the shape of the outer surface 43a of the column portion 43 in Figure 3.

[0036] As shown in FIGS. 1 and 3, an outer surface 43a of the column portion 43 is continuous with the outer periphery 41a of the small diameter side annular portion 41 and the outer periphery a of the large diameter side annular portion .

[0037] As shown in Fig. 1, the column portion 43 has a shape in which the outer surface 43a is recessed. This recessed shape of the outer surface 43a is formed by the crimping process performed during assembly of the inner ring assembly described above. As the crimping process plastically deforms the outer surface 43a into a recessed shape, the inner surface 43b of the column portion 43 shown in Fig. 2 is plastically deformed so as to bulge in accordance with the recessed shape of the outer surface 43a, and the column portion 43 is bent in accordance with the recessed shape of the outer surface 43a shown in Fig. 1. In other words, the crimping process causes the bent portion of the column portion 43, where the outer surface 43a is recessed, to approach the tapered roller 30 in the radial direction, and as a result, the gap (radial gap) between the tapered roller 30 and the guide surface 43c (see Fig. 3) included in this bent portion is reduced. As a result, as shown in Figures 2, 4, and 5, the radial gap (δ1 / 2) between the tapered roller 30 and the small diameter side of the base portion 43 is smaller than the radial gap (δ2 / 2) between the tapered roller 30 and the large diameter side of the base portion 43. In other words, the minimum value of the gap (δ1 / 2) on the small diameter side is smaller than the minimum value of the gap (δ2 / 2) on the large diameter side. Note that in Figures 4 and 5, the gaps (δ1 / 2) and (δ2 / 2) are exaggerated. Also, the cross sections in Figures 4 and 5 show the small diameter side and the large diameter side, respectively, with the imaginary line Pc as the boundary, and the magnitude relationship of the minimum clearances within that range is compared.

[0038] One method for measuring the clearances (δ1 / 2) and (δ2 / 2) is to, for example, assemble the steel plate cage 40, tapered rollers 30, and inner ring 10 into an assembly, set the outer surface 43a of each column portion 43 of the steel plate cage 40 in a measuring jig that is fixed in both the axial and circumferential directions on either the small diameter side or the large diameter shaft to be measured, move the inner ring 10 radially, and calculate the clearances (δ1 / 2) and (δ2 / 2) from the value measured for the amount of movement using a contact or non-contact measuring device.

[0039] 2, tapered rollers 30 come into contact with one of the guide surfaces 43c (see FIG. 3) of a pair of pillar portions 43 located on both circumferential sides of pocket 44 depending on the speed difference between the rotational speed of steel plate cage 40 and the orbital speed of tapered rollers 30, and are kept in a stable position by sliding contact with large rib 12 of inner ring 10 in a fluid lubricated state. Depending on various bearing usage conditions, tapered rollers 30 may not be fully guided by large rib 12 and one of the guide surfaces 43c, causing the behavior of tapered rollers 30 to become unstable and causing tapered rollers 30 to swing in the skew or tilt direction. The skew behavior of the tapered roller 30 refers to the central axis CL2' of the tapered roller 30 vibrating in a direction that forms an angle θ1 in the circumferential direction with respect to the normal direction (see Figure 2), as shown in Figure 6, and the tilt behavior of the tapered roller 30 refers to the central axis CL2'' of the tapered roller 30 vibrating in a direction that forms an angle θ2 in the radial direction with respect to the normal direction.

[0040] When the behavior of the tapered roller 30 becomes disturbed, the tapered roller 30 can sway in the skew direction or tilt direction within the range of the gap (see Figures 4 and 5) between a pair of pillar portions 43 (see Figure 3) located on both sides of the circumferential direction, but if it sways beyond that, the small diameter side of the tapered roller 30 will be restrained by the guide surfaces 43c (see Figure 3) of the pair of pillar portions 43, and the behavior of the tapered roller 30 will be suppressed.

[0041] Here, the dashed line L1 shown in FIGS. 1 and 3 is an imaginary line that is included in any imaginary plane that includes the center axis of the steel plate cage 40 and intersects with the outer surface 43a, and that is tangent to the outer periphery 41a of the small-diameter side annular portion and the outer periphery 42a of the large-diameter side annular portion 42 on the imaginary plane. The distance between the imaginary line L1 and the outer surface 43a of the column portion 43 is defined as the depth of the recess formed on the outer surface 43a, and the deepest part on the outer surface 43a is defined as the deepest point Pmax. The depth of the deepest point Pmax is defined as Dp. The depth Dp of the deepest point Pmax is the distance between the imaginary line L1 and the imaginary line L2 when the imaginary line L2, which is parallel to the imaginary line L1, intersects with the deepest point Pmax on the outer surface 43a, as shown in FIG.

[0042] The concave portion of the outer surface 43a of the column portion 43 is shaped so that its depth becomes shallower from the deepest point Pmax toward the outer periphery 41a of the small diameter side annular portion 41 and toward the outer periphery 42a of the large diameter side annular portion 42.

[0043] 1 and 3, the deepest point Pmax of the outer surface 43a of the pillar portion 43 is formed so as to be located on the small diameter side (left side of the line Pc) of the pillar portion 43. For this reason, during the crimping process, the guide surface 43c (see FIG. 3) on the small diameter side of the pillar portion 43 is brought particularly close to the small diameter side of the rolling surface 31 of the tapered roller 30. The position where the gap (δ1 / 2, see FIG. 4) on the small diameter side is smallest is substantially on an imaginary plane (lead line indicating the maximum depth Dp) that is parallel to the imaginary line Pc and includes the deepest point Pmax of the outer surface 43a. As a result, on the smaller diameter side of the column portion 43, that is, on the position of the swing tip side of the tapered roller 30 opposite the large rib 12 (see FIG. 2) of the inner ring 10 that guides the large diameter side of the tapered roller 30, a range where the gap on the small diameter side (δ1 / 2, see FIG. 4) is particularly small exists with a width in the axial direction at a position some distance from the large rib 12 (see FIG. 2), so the swing tip side of the tapered roller 30 is strongly restrained early on. Therefore, the effect of suppressing the behavior of the tapered roller 30 is particularly excellent.

[0044] The depth Dp of the deepest part Pmax shown in Fig. 1 is 10 µm or more and 200 µm or less, preferably 20 µm or more and 150 µm or less, and more preferably 30 µm or more and 100 µm or less. If the depth Dp of the deepest part Pmax is less than 5 µm, the gap (δ1 / 2, see Fig. 4) on the small diameter side does not become very small, and the effect of suppressing the behavior of the tapered roller 30 (see Figs. 2 and 6) is small. If it exceeds 300 µm, the gap (δ1 / 2, see Fig. 4) on the small diameter side becomes excessively small, and the contact force between the rolling surface 31 of the tapered roller 30 and the guide surface 43c becomes too high, which may hinder smooth rotation of the tapered roller 30.

[0045] Furthermore, it is necessary to provide a radial gap (see FIGS. 4 and 5) between the column portion 43, the rolling surface 31 of the tapered roller 30, and the raceway surface 11 (see FIG. 2). If the aforementioned radial gap is set too small to suppress skew and tilt movement of the tapered roller 30, the whirling movement of the steel plate cage 40 will be insufficient from the state shown in FIG. 2, resulting in a strong contact between the column portion 43 and the rolling surface 31, which will induce oil film rupture at the rolling contact area between the column portion 43 and the rolling surface 31 and raise the concern of premature damage. For this reason, it is necessary to allow a certain degree of whirling of the steel plate cage 40 (see FIG. 2) by the aforementioned radial gap (see FIGS. 4 and 5). Taking this into consideration, the minimum value of the clearance on the small diameter side (δ1 / 2, see FIG. 4) is 0.01 mm or more and 0.12 mm or less, preferably 0.03 mm or more and 0.10 mm or less. This makes it possible to realize excellent performance in suppressing the behavior of the tapered rollers 30 (see FIGS. 2 and 6), while allowing appropriate whirling of the steel plate cage 40.

[0046] Here, in the calculation using the outer diameter φD of the steel plate cage 40, the inner diameter φd of the steel plate cage 40, the length Lw of the pocket 44 (see FIG. 3), and the depth Dp of the deepest part Pmax (see FIG. 1), (φD / φd) × (Lw / Dp) = cage coefficient. The overall size of the steel plate cage 40 is largely dependent on the outer diameter φD, the inner diameter φd of the steel plate cage 40, and the length Lw of the pocket 44 (post portion 43). The thickness of the steel plate material used as the raw material is selected so that appropriate rigidity is obtained depending on the overall size of the steel plate cage 40. The plate thickness affects the concave forming of the outer surfaces 43a of the post portions 43 and the narrowing of the gaps due to the aforementioned caulking process. If the condition 100<retainer coefficient<1300 is satisfied, the aforementioned concave shape can be effectively imparted to the outer surface 43a (see Figure 1) of the column portion 43 for the tapered rollers 30 while taking into account appropriate rigidity according to the size of the steel plate retainer 40 (see Figure 3).

[0047] As described above, this tapered roller bearing comprises an inner ring 10, an outer ring 20, a plurality of tapered rollers 30 arranged between the inner ring 10 and the outer ring 20, and a steel plate cage 40 that holds the plurality of tapered rollers 30, the inner ring 10 integrally having a raceway surface 11, a large rib 12 and a small rib 13, the steel plate cage 40 integrally having a small diameter side annular portion 41, a large diameter side annular portion 42 and a plurality of pillar portions 43 that separate the space between the small diameter side annular portion 41 and the large diameter side annular portion 42 into a plurality of pockets 44, and the pillar portions 43 have outer surfaces 43a that are continuous with the outer periphery 41a of the small diameter side annular portion 41 and the outer periphery 42a of the large diameter side annular portion 42. In particular, by adopting a pillar portion 43 in which the outer surface 43a of the pillar portion 43 is recessed so that the gap (δ1 / 2) between the tapered roller 30 and the small diameter side of the pillar portion 43 is smaller than the gap (δ2 / 2) between the tapered roller 30 and the large diameter side of the pillar portion 43, the gap (δ1 / 2) on the small diameter side is set smaller than the gap (δ2 / 2) on the large diameter side based on the recessed shape of the outer surface of the pillar portion, so that when the behavior of the tapered roller 30 becomes unstable, the tip side (small diameter side) of the tapered roller 30 is received by the pillar portion 43 early on, and the behavior of the tapered roller 30 can be suppressed.

[0048] Furthermore, making the gap (δ1 / 2) on the smaller diameter side smaller than the gap (δ2 / 2) on the larger diameter side is achieved by plastic deformation of the column sections 43, where the column sections 43 are slightly bent based on the recessed shape of the outer surfaces 43a of the column sections 43, and this can be achieved by slightly modifying the shape of the mold used in the crimping process when assembling the inner ring assembly. Therefore, this tapered roller bearing does not require major changes to the structure of the steel plate cage 40, and can impart to the steel plate cage 40 the characteristic of suppressing the behavior of the tapered rollers 30 by inexpensive means that do not impair the ease of manufacture of the inner ring assembly.

[0049] Therefore, this tapered roller bearing can suppress the behavior of the tapered rollers 30 using inexpensive means that does not require major changes to the structure of the steel plate cage 40 and does not impair the ease of manufacturing the inner ring assembly.

[0050] Furthermore, in this tapered roller bearing, when the distance between an imaginary straight line L1 tangent to the outer periphery 41a of the small-diameter side annular portion 41 and the outer periphery 42a of the large-diameter side annular portion 42 and the outer surface 43a of the pillar portion 43 is taken as the depth of the concave shape molded on the outer surface 43a of the pillar portion 43, the deepest part Pmax having the maximum depth Dp on the outer surface 43a of the pillar portion 43 is molded on the small-diameter side of the pillar portion 43, so that the gap (δ1 / 2) on the small-diameter side of the pillar portion 43 (closer to the tip of the tapered roller 30) is particularly small, and the behavior of the tapered roller 30 can be more effectively suppressed.

[0051] Furthermore, this tapered roller bearing has a depth Dp of the deepest part Pmax of 10 μm or more and 200 μm or less, thereby improving the effect of suppressing the behavior of the tapered rollers 30 while preventing the gap (δ1 / 2) on the small diameter side from becoming excessively small, thereby not interfering with the smooth rotation of the tapered rollers 30.

[0052] Furthermore, in this tapered roller bearing, when the outer diameter of the steel plate retainer 40 is φD, the inner diameter of the steel plate retainer 40 is φd, the length of the pocket 44 is Lw, the distance between the imaginary line L1 tangent to the outer circumference 41a of the small diameter side annular portion 41 and the outer circumference 42a of the large diameter side annular portion 42 and the outer surface 43a of the bar portion 43 is the depth of the concave shape formed on the outer surface 43a of the bar portion 43, the maximum depth on the outer surface 43a of the bar portion 43 is Dp, and (φD / φd)×(Lw / Dp)=retainer coefficient, the steel plate retainer 40 satisfies 100<retainer coefficient<1300, so that the above-mentioned concave shape can be effectively imparted to the outer surface 43a of the bar portion 43 with appropriate rigidity according to the size of the steel plate retainer 40.

[0053] Furthermore, this tapered roller bearing has a minimum gap (δ1 / 2) between the small diameter side of the column portion 43 and the tapered roller 30 of 0.01 mm or more and 0.12 mm or less, thereby achieving excellent behavior suppression performance of the tapered roller 30 while avoiding strong contact between the tapered roller 30 and the column portion 43 under normal conditions.

[0054] In this tapered roller bearing, the deepest point Pmax of the outer surface 43a of the column portion 43 is formed in a position closer to the outer periphery 41a of the small-diameter side annular portion 41 within the small-diameter side part of the column portion 43, thereby making it possible to suppress the behavior of the tapered rollers 30 particularly at the swing tip side, but the shape of the recess in the outer surface of the column portion can be various shapes other than that shown in Figure 1. For example, as shown in Figures 7 to 9, the position of the deepest point Pmax and the maximum depth Dp can be changed appropriately so as to obtain the required tapered roller behavior suppression performance based on the above-mentioned cage coefficient. Furthermore, the recess in the outer surface of the column portion may exist over part of the length of the column portion, or over the entire length.

[0055] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined 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]

[0056] 10. Inner Circle 11 Raceway surface 12 Otsuba 13 Kotsuba 20 outer ring 30 Tapered roller 40 Steel plate retainer 41 Small diameter annular section 42 Large diameter annular portion 43 Pillar part 43a Exterior 44 pockets

Claims

1. The bearing comprises an inner ring, an outer ring, a plurality of tapered rollers arranged between the inner ring and the outer ring, and a steel plate cage that holds the plurality of tapered rollers, the inner ring integrally has a raceway surface, a large rib, and a small rib, In a tapered roller bearing, the steel plate cage integrally comprises a small diameter side annular portion, a large diameter side annular portion, and a plurality of pillar portions that separate the space between the small diameter side annular portion and the large diameter side annular portion into a plurality of pockets, and the pillar portions have outer surfaces that are continuous with the outer peripheries of the small diameter side annular portion and the large diameter side annular portion, A tapered roller bearing characterized in that the column portion has a shape in which the outer surface of the column portion is recessed so that the gap between the tapered roller and the small diameter side of the column portion is smaller than the gap between the tapered roller and the large diameter side of the column portion.

2. 2. A tapered roller bearing according to claim 1, wherein when the distance between an imaginary line tangent to the outer periphery of the small diameter side annular portion and the outer periphery of the large diameter side annular portion and the outer surface of the base portion is defined as the depth of the concave shape molded in the outer surface of the base portion, the deepest part having the greatest depth in the outer surface of the base portion is molded on the small diameter side of the base portion.

3. 3. A tapered roller bearing according to claim 2, wherein the depth of the deepest part is 10 μm or more and 200 μm or less.

4. 4. The tapered roller bearing according to claim 1, wherein the outer diameter of the iron plate cage is φD, the inner diameter of the iron plate cage is φd, the length of the pocket is Lw, the distance between an imaginary line tangent to the outer periphery of the small diameter side annular portion and the outer periphery of the large diameter side annular portion and the outer periphery of the bar portion is the depth of the concave formed in the outer surface of the bar portion, and the maximum depth in the outer surface of the bar portion is Dp, and (φD / φd) × (Lw / Dp) = cage coefficient, the iron plate cage satisfies 100 < cage coefficient < 1300.

5. 5. A tapered roller bearing according to claim 1, wherein the minimum value of the gap between the small diameter side of the column portion and the tapered roller is 0.01 mm or more and 0.12 mm or less.

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