JP2017187148A - Rolling body for conical roller bearing, and conical roller bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling body for a conical roller bearing capable of suppressing occurrence of skew and high in high-speed rotation performance.SOLUTION: A surface shape of a roller large-diameter surface 22 is a torus surface formed by rotating a circular arc D, which is separated from a roller center shaft C1 by δ and which has a center Oon the same side as the center shaft C1, around the roller center shaft C1. A curvature radius Rca in a circumference direction of the roller large-diameter end surface 22 is made larger than a curvature radius Rcb in a circumferential direction of a large flange surface 17. The large-diameter end surface 22 and the large flange surface 17 contact with each other at two points E separated from each other in the circumferential direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rolling element for a tapered roller bearing and a tapered roller bearing.

  In the conventional tapered roller bearing, the surface shape of the roller large-diameter end surface of the tapered roller is formed by a spherical surface, and the large collar surface of the inner ring is formed by a conical surface, and the roller large-diameter end surface and large collar surface of the tapered roller are Touch at one point. When such a tapered roller is skewed, the contact point between the roller large-diameter end face and the large collar surface moves to the edge side of the tapered roller and the outer diameter side of the large collar surface. By moving the contact in this manner, a moment is generated in a direction that suppresses skew by the load at the contact. The larger the moment is with respect to the amount of skew of the tapered roller, the higher the effect of suppressing the skew of the tapered roller bearing, and seizure due to high-speed rotation hardly occurs.

  For example, as shown in FIG. 13, when comparing a tapered roller 100A having a large radius of curvature R at the end surface of the large roller and a tapered roller 100B having a small radius of curvature R, the tapered roller 100A having a larger radius of curvature R is the contact point. Since the movement distance H is large, the moment M is large even if the skew amount α is the same.

  Patent Document 1 proposes a tapered roller bearing that suppresses the skew of the tapered roller by focusing on the contact between the large diameter end surface of the tapered roller and the large collar surface of the inner ring. In the tapered roller bearing of Patent Document 1, the large-diameter end surface of the tapered roller that contacts the large collar surface is a convex spherical surface, and the large collar surface is a concave spherical surface. Further, by setting the curvature radius of the convex spherical surface (the large diameter end surface of the tapered roller) to be smaller than the curvature radius of the concave spherical surface (the inner peripheral surface of the large collar surface), the roller large diameter end surface of the tapered roller and the large collar The surface is in contact with one point. This tapered roller bearing has a concave spherical shape on the large brim surface, so compared to a tapered roller bearing having a conical surface on the large brim surface, it is a contact point between the large diameter end surface of the tapered roller and the large brim surface. The contact ellipse generated by elastic deformation becomes large. Further, when the tapered roller is skewed, the moving distance of the contact point between the roller large-diameter end face and the large brim surface is increased, so that the restoring moment is increased and a large skew suppressing effect is obtained.

  In the tapered roller bearing of Patent Document 2, the curved surface shape of the roller large-diameter end surface is a curved surface shape obtained by rotating an arc having a center on the opposite side of the roller center axis around the roller center axis, and has a radius of curvature in the roller circumferential direction. Is set larger than the radius of curvature in the roller radial direction. Moreover, the surface shape of the large collar surface of the inner ring is a conical surface shape having a center on the bearing rotation shaft. The roller large-diameter end surface and the large collar surface of the inner ring are in sliding contact at one point. As a result, the contact ellipse between the roller large-diameter end face and the large collar surface of the inner ring is the same as the contact ellipse with a large contact area, without changing the length in the major axis direction, only in the length in the minor axis direction. The bearing loss is reduced by reducing the contact surface pressure.

  The roller large-diameter end surface of the tapered roller of Patent Document 3 is formed at the central portion of the large end surface, and has a spherical surface having a center on the roller central axis and an arc having no center on the roller central axis. It is composed of two curved surfaces, a curved surface rotated around the roller central axis. The large collar surface of the inner ring is in contact with the central portion of the large end surface, and the outer edge portion of the large end surface avoids edge contact even if the tapered roller is skewed, and makes it difficult to cause seizure of the contact portion. .

JP 2001-173665 A JP 2002-147461 A JP 2006-316837 A

  However, according to the tapered roller bearing of Patent Document 1, a sufficient restoring moment cannot be obtained while the skew amount is small and the contact movement amount is small as in the initial stage of skew. There was a problem that it was not stable unless it was skewed.

  Further, the tapered roller bearing of Patent Document 2 is intended to reduce the contact loss by reducing the contact surface pressure by expanding the contact area, and has a radius of curvature related to the circumferential length of the contact surface. No regulation has been made and no skew suppression effect can be expected.

  Further, the tapered roller bearing of Patent Document 3 is for preventing edge contact at the time of occurrence of skew due to the curved surface of the outer edge of the large end surface, and the curved surface formed at the center of the large end surface and the large collar surface of the inner ring. The contact is a sliding contact at one point, and does not suppress the occurrence of skew itself.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a rolling element for a tapered roller bearing and a tapered roller bearing that have high-speed rotation performance while suppressing the occurrence of skew. .

The above object of the present invention can be achieved by the following constitution.
(1) A rolling element for a tapered roller bearing, comprising a roller large-diameter end surface having a surface shape obtained by rotating an arc having a center of curvature away from the roller center axis around the roller center axis.
(2) The rolling element for a tapered roller bearing according to (1), wherein a surface shape of the roller large-diameter end surface is a torus surface.
(3) The roller large-diameter end face is a rolling element for a tapered roller bearing according to (1) or (2), which is in contact with the large collar surface of the inner ring at two points in the circumferential direction.
(4) an outer ring having an outer ring raceway surface on the inner peripheral surface;
An inner ring having an inner ring raceway surface on the outer peripheral surface;
A plurality of rolling elements according to (1) or (2), arranged so as to be freely rollable between the outer ring raceway surface and the inner ring raceway surface,
A tapered roller bearing, wherein a large collar surface of the inner ring that contacts a roller large-diameter end surface of the rolling element is a conical surface having a center on a rotating shaft of the tapered roller bearing.
(5) The surface shape of the roller large-diameter end surface is a torus surface formed by rotating an arc having a center on the same side as the roller central axis around the roller central axis,
The roller large-diameter end face of the rolling element and the large collar face of the inner ring contact at two points in the circumferential direction,
In a cross section including the roller center axis and the bearing center axis, a circumferential direction of the roller large diameter end surface at a point on the roller large diameter end surface at which the distance between the roller large diameter end surface and the large collar surface is minimized. The curvature radius Rca and the curvature radius Rcb in the circumferential direction of the large brim surface at a point on the large brim surface where the distance between the large-diameter end surface of the roller and the large brim surface is minimized have a relationship of Rcb <Rca. The tapered roller bearing according to (4), wherein
(6) The radius of the arc of the roller large-diameter end surface is Rra, the distance between the center of the arc and the roller central axis is δ, and the distance between the roller large-diameter end surface and the large collar surface is minimal. The distance from a point on the collar surface to the apex of the conical surface forming the large collar surface is L, the half apex angle of the rolling surface of the rolling element is β, the half apex angle of the inner ring raceway surface is γ, and the large When the half apex angle of the conical surface of the collar surface is π / 2−φ,
L / tanφ <Rra + δ / sin (β + γ−φ)
The tapered roller bearing according to (5), which satisfies the relational expression:
(7) The surface shape of the roller large-diameter end surface is formed by rotating an arc having a center on the opposite side of the roller central axis around the roller central axis,
The radius of the arc of the roller large-diameter end surface is Rra, the distance between the center of the arc and the roller central axis is δ, and the conical surface of the large-rib surface from the contact point between the roller large-diameter end surface and the large collar surface. The distance to the apex is L, the half apex angle of the rolling surface of the rolling element is β, the half apex angle of the inner ring raceway surface is γ, and the half apex angle of the conical surface of the large brim surface is π / 2−φ. When
{Rra-δ / sin (β + γ-φ)) / (L / tanφ) ≧ 0.85
The tapered roller bearing according to (4), wherein
(8) The surface shape of the roller large-diameter end face is two arcs of a first arc and a second arc having a center at a position deviating from the roller center axis in a cross section including the roller center axis and the bearing center axis. Are each a convex convex surface formed by rotating around the central axis of the roller,
The tapered roller bearing according to (4), wherein the large collar surface and the roller large-diameter end surface of the rolling element contact at two points.
(9) The radius of the first arc of the roller large diameter end surface is Rr1, the radius of the second arc of the roller large diameter end surface is Rr2, and the distance between the center of the first arc and the roller central axis is δ1, The distance between the center of the second arc and the roller central axis is δ2, the distance from the contact point between the first arc and the large brim surface to the apex of the conical surface of the large brim surface is L1, and the second arc The distance from the contact point with the large brim surface to the apex of the conical surface of the large brim surface is L2, the half apex angle of the rolling surface of the rolling element is β, the half apex angle of the inner ring raceway surface is γ, When the half apex angle of the conical surface of the collar surface is π / 2−φ,
{Rrn−δn / sin (β + γ−φ)) / (Ln / tanφ) ≧ 0.85 (n = 1, 2)
The tapered roller bearing according to (8), wherein the following relational expression is satisfied.

  According to the rolling element for tapered roller bearing and tapered roller bearing of the present invention, the shape of the roller large-diameter end surface is formed by rotating an arc having a center of curvature at a position away from the roller center axis around the roller center axis. Provided with rolling elements. This suppresses skew between the roller large-diameter end surface of the rolling element and the large collar surface of the inner ring, which is a conical surface having a center on the rotation axis of the tapered roller bearing, and the roller large-diameter end surface of the rolling element. Heat generation due to friction between the inner ring and the large collar surface of the inner ring is reduced and high-speed rotation performance is improved.

It is sectional drawing of the tapered roller bearing which concerns on 1st Embodiment of this invention. It is sectional drawing containing the roller center axis | shaft of the tapered roller shown in FIG. It is sectional drawing containing the bearing central axis of the inner ring | wheel shown in FIG. It is a side view which shows the state which the roller large diameter end surface of the tapered roller shown in FIG. 1 and the large collar surface of an inner ring contact at two points. FIG. 2 is an enlarged view of a portion surrounded by a circle V in FIG. 1. It is sectional drawing of the tapered roller bearing which concerns on 2nd Embodiment of this invention. It is sectional drawing containing the roller center axis | shaft of the tapered roller shown in FIG. In the conventional tapered roller bearing, it is the figure which projected on the plane parallel to a contact surface the range from which the distance of the roller large diameter end surface of a tapered roller and the large collar surface of an inner ring | wheel is 1 micrometer or less. FIG. 7 is a diagram in which a range in which the distance between the roller large-diameter end surface of the tapered roller and the large collar surface of the inner ring is 1 μm or less in the tapered roller bearing shown in FIG. 6 is projected on a plane parallel to the contact surface. It is a graph which shows the relationship between the curvature radius ratio of the tapered roller bearing shown in FIG. 6, and the area where the distance of a roller large diameter end surface and a large collar surface is 1 micrometer or less. It is sectional drawing of the tapered roller bearing which concerns on 3rd Embodiment of this invention. FIG. 12 is an enlarged view of a portion surrounded by a circle XII in FIG. 11. FIG. 5 is a schematic diagram illustrating a skew state in a conventional tapered roller bearing in which a tapered roller having a large-diameter end surface is in contact with a convex spherical surface and a large flange surface having a conical shape.

  Hereinafter, rolling elements for tapered roller bearings and tapered roller bearings according to embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a sectional view including a bearing central axis and one roller central axis of a tapered roller bearing according to a first embodiment of the present invention, FIG. 2 is a sectional view of a tapered roller including a roller central axis, and FIG. 3 is a bearing of an inner ring. It is sectional drawing containing a central axis.

  As shown in FIG. 1, the tapered roller bearing 10 of this embodiment includes an outer ring 12 having an outer ring raceway surface 11 provided on an inner peripheral surface, an inner ring 14 provided with an inner ring raceway surface 13 on an outer peripheral surface, and an outer ring raceway. A plurality of tapered rollers 15 which are rolling elements arranged between the surface 11 and the inner ring raceway surface 13.

Referring also to FIG. 3, the inner ring 14 includes a flange portion (large diameter flange portion) 16 provided at an end portion in the axial direction on the large diameter side with respect to the inner ring raceway surface 13. The inner ring raceway surface 13 of the inner ring 14 is a conical surface with a half apex angle γ having a vertex O ₂ on the bearing center axis C2, and the large collar surface 17 (the inner peripheral surface of the flange portion 16) of the inner ring 14 is the bearing center. It is a conical surface having an apex O ₃ on the axis C2 and a half apex angle π / 2−φ. That is, the radius of curvature Rrb in the radial direction of the large brim surface 17 at the point P on the large brim surface 17 is ∞, and the radius of curvature Rcb in the circumferential direction at the point P on the large brim surface 17 is The distance from the point P to the intersection of the perpendicular of the large brim surface 17 passing through the point P and the bearing central axis C2. Further, since the rolling surface 21 of the tapered roller 15 is a conical surface having a half apex angle β, the outer ring raceway surface 11 of the outer ring 12 is a conical surface having a half apex angle γ + 2β.

Referring to FIG. 2 as well, the shape of the roller large-diameter end face 22 is on the same side with respect to the roller center axis C1 (lower side of the roller center axis C1 in FIG. 2) at a position separated by δ from the roller center axis C1. This is a rotation surface obtained by rotating an arc D having a radius Rra around a point O ₁ around the roller central axis C1. Therefore, the shape of the roller large-diameter end surface 22 is represented by a radius of curvature Rra in the radial direction at a point Q on the roller large-diameter end surface 22 and a radius of curvature Rca in the circumferential direction at the point Q on the roller large-diameter end surface 22. An aspherical surface (torus surface).
Note that the radius of curvature Rca in the circumferential direction is the length of a line connecting the point Q and the point O ₄ , and the point O ₄ is an intersection of the line O ₁ Q and the central axis C ₁ . Further, the shape of the small diameter end face 23 of the tapered roller 15 is an arbitrary shape.

  In the tapered roller bearing 10 including the tapered roller 15 having a roller large-diameter end surface 22 having an aspherical shape, the rolling surface 21 of the tapered roller 15 and the inner ring raceway surface 13 coincide with each other and are in line contact with each other. 4, the roller large-diameter end surface 22 of the tapered roller 15 and the large collar surface 17 of the inner ring 14 are in contact at two points E that are separated in the circumferential direction.

  FIG. 5 is an enlarged view of a portion surrounded by a circle V in FIG. 1, and is a cross-sectional view including the bearing center axis C <b> 2 of the tapered roller bearing 10 and one roller center axis C <b> 1. The tapered roller bearing 10 does not have a point E where the roller large-diameter end face 22 and the large collar surface 17 are in contact with each other on the cross-section including the bearing central axis C2 and the central axis C1. There is a gap S between the flange surface 17 and the large-diameter end surface 22.

Here, the point on the large brim surface 17 where the gap S between the large brim surface 17 and the large diameter end surface 22 is minimum is P, the point on the roller large diameter end surface 22 is Q, and the point P When the distance to the center O ₃ on the bearing axis C2 and L (see FIG. 1), rollers and the large diameter end faces 22 and the large rib face 17, has two point E in contact with circumferentially spaced Therefore, there is a relationship of Rcb <Rca between the radius of curvature Rcb in the circumferential direction of the large brim surface 17 at the point P and the radius of curvature Rca in the circumferential direction of the roller large diameter end surface 22 at the point Q. To establish.

  Here, the radius of curvature Rcb in the circumferential direction of the large brim surface 17 can be approximated by L / tanφ, and the radius of curvature Rca in the circumferential direction of the roller large diameter end surface 22 can be approximated by Rra + δ / sin (β + γ−φ). Therefore, the relationship of Formula (1) is materialized.

  L / tanφ <Rra + δ / sin (β + γ−φ) ――― (1)

Accordingly, the contact between the roller large-diameter end surface 22 of the tapered roller 15 and the large collar surface 17 of the inner ring 14 at two points satisfies the radius Rra and the radius of the roller large-diameter end surface 22 so as to satisfy Expression (1). by determining the distance δ between the center O ₁ at the center axis C1 of Rra, it is achieved.

As described above, the surface shape of the roller large-diameter end face 22 of the tapered roller 15 is obtained by rotating the arc D having the center O ₁ away from the roller center axis C1 around the roller center axis C1. Since it is a spherical surface (torus surface), the radius of curvature Rra of the roller large-diameter end surface 22 and the radius of curvature Rca in the circumferential direction are set to different values.

The tapered roller bearing 10 of the present embodiment has a roller large-diameter end surface 22 of the tapered roller 15 and a large collar surface 17 of the inner ring 14 that is a conical surface having a center O ₂ on the rotation axis C2 of the tapered roller bearing. Since the contact is made at two points E that are separated from each other in the circumferential direction, the point E corresponds to the edge side of the roller large-diameter end face 22 and the large brim surface 17 as compared with the conventional one-point contact tapered roller bearing. Contact on the outer diameter side. Therefore, the restoring force when the skew is generated in the tapered roller 15 is increased, and even when the skew amount is small, the restoring force is restored and the stability against the skew is improved. As a result, heat generation due to friction between the roller large-diameter end surface 22 of the tapered roller 15 and the large collar surface 17 of the inner ring 14 due to skew can be suppressed, seizure can be prevented, and high-speed rotation performance is improved. .

The surface shape of the roller large-diameter end surface is a torus surface formed by rotating an arc D having the center O ₁ on the same side as the roller central axis C1 around the roller central axis C1, and the roller large-diameter end surface 22 The radius of curvature Rca in the circumferential direction of the roller large-diameter end surface 22 at a point Q on the roller large-diameter end surface 22 at which the distance S between the roller large-diameter surface 17 and the large collar surface 17 is minimal, and the roller large-diameter end surface 22 and the large collar surface 17 When the radius of curvature Rcb in the circumferential direction of the large brim surface 17 at the point P on the large brim surface 17 at which the distance S is minimal satisfies the relationship Rcb <Rca, the roller large-diameter end surface 22 and the large brim surface 17 Contact at two points E that are spaced apart in the circumferential direction.

Moreover, such a tapered roller bearing 10 is a roller Rra the radius of the arc D of the large-diameter side end surface 22, the distance between the center O ₁ at the center axis C1 of the arc D [delta], around the large diameter end faces 22 large rib surface 17 L is the distance from the point P on the large brim surface 17 at which the distance S to the minimum to the apex O _{3 of the} conical surface forming the large brim surface 17, and the half apex angle of the rolling surface 21 of the tapered roller 15 is β When the half apex angle of the inner ring raceway surface 13 is γ and the half apex angle of the conical surface of the large brim surface 17 is π / 2−φ, the relational expression L / tanφ <Rra + δ / sin (β + γ−φ) is satisfied. ing.

(Second Embodiment)
Next, a tapered roller bearing according to a second embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol or an equivalent code | symbol is attached | subjected to the same or equivalent part as 1st Embodiment, and description is simplified or abbreviate | omitted.

  In the tapered roller bearing 10 of the first embodiment, the roller large-diameter end face 22 and the large brim surface 17 are in contact with each other at two points E that are separated in the circumferential direction. In the tapered roller bearing 10 </ b> A of the embodiment, the contact surface between the roller large-diameter end surface 22 and the large collar surface 17 is widened in the circumferential direction, thereby suppressing skew.

  Specifically, the contact surface between the roller large-diameter end surface 22 and the large brim surface 17 becomes elliptical due to elastic deformation. The wider the contact surface, or the higher the contact surface as viewed from the inner ring raceway surface 13, the higher the effect of suppressing the skew of the tapered rollers 15A.

The radius of curvature of the roller large-diameter end surface 22 at the contact point P between the roller large-diameter end surface 22 and the large brim surface 17 is Rra, and the radius of curvature of the roller large-diameter end surface 22 in the circumferential direction (point P and point O ₄ is connecting length of the line) to Rca, Rcb radial radius of curvature Rrb of the large rib surface 17, the circumferential direction of the radius of curvature of the large rib surface 17 (the length of a line connecting the point P and the point O ₂₎ Then, since the large brim surface 17 is a conical surface, Rrb = ∞, and the larger the Rcb, the wider the contact surface in the radial direction.

  Further, as the value of Rca-Rcb approaches 0, the roller large-diameter end surface 22, the large brim surface 17, and the contact surface approach line contact and expand in the circumferential direction, but at the same time, the contact P decreases. This is because as the position of the contact P is lowered, Rca increases and Rcb decreases.

If the shape of the roller large-diameter end surface 22 is a spherical shape as in the prior art, since Rra = Rca, the contact surface cannot be widened without lowering the contact. On the other hand, in the tapered roller bearing 10A of the present embodiment, as shown in FIG. 7, the radius Rra having a center O _{1 in} which the shape of the roller large-diameter end face 22 of the tapered roller 15A is separated from the roller center axis C1 by δ. Since the arc D is a rotating surface (aspherical surface) rotated about the roller center axis C1, the radius of curvature Rra in the radial direction can be increased without changing the radius of curvature Rca in the circumferential direction. The contact surface can be widened.

In addition, the surface shape of the roller large-diameter end surface 22 of the present embodiment is a shape in which two circular arcs D symmetrical to the roller center axis C1 are connected. Unlike the tapered roller 15 of the first embodiment, the radius Rra an arc D of the center O ₁ of the arc D, located opposite each other with respect to the central axis C1 rollers.

  In this tapered roller bearing 10A, the difference in the radius of curvature (Rca-Rcb) in the circumferential direction between the roller large-diameter end surface 22 and the large brim surface 17 approaches zero, or between the roller large-diameter end surface 22 and the large brim surface 17. As the ratio Kr = Rca / Rcb of the radius of curvature in the circumferential direction approaches 1, the contact surface approaches line contact and becomes longer in the circumferential direction.

  Referring to FIG. 6, in the tapered roller bearing 10A of the present embodiment, the radius of curvature Rcb in the circumferential direction of the large collar surface 17 at the contact point P between the roller large diameter end surface 22 and the large collar surface 17 is L / tanφ. Can be approximated. Further, the radius of curvature Rca in the circumferential direction of the roller large-diameter end face 22 at the contact P can be approximated by Rra−δ / sin (β + γ−φ).

Accordingly, the curvature radius ratio Kr (Rca / Rcb) is expressed by the following equation (2).
Kr = {Rra−δ / sin (β + γ−φ)} / (L / tanφ) −− (2)

  Here, by determining Rra and δ so that the curvature radius ratio Kr approaches 1, the contact surface between the roller large-diameter end surface 22 and the large brim surface 17 is longer in the circumferential direction, and the contact surface becomes wider. The effect of suppressing skew is improved.

  FIG. 8 and FIG. 9 project the range in which the distance between the roller large-diameter end surface and the large collar surface is 1 μm or less on a plane parallel to the contact surface for each of the conventional bearing and the bearing of this embodiment. FIG. Here, β = 1.5 °, γ = 13.2 °, π / 2−φ = 76.4 ° (φ = 13.6 °), and the outermost diameter of the inner ring raceway surface 13 = 85 mm. . Further, in the conventional bearing (FIG. 8), the roller large-diameter end face has a spherical shape with Rra = 177 mm and δ = 0 mm. In the bearing of this embodiment (FIG. 9), the roller large-diameter end face Rra = 355 mm, δ = 3.4 mm aspherical surface.

  In both bearings, L = 45 mm, the contact height is equal, and the curvature radius ratio is the same as Kr = 0.95. However, the bearing of this embodiment shown in FIG. And a large collar surface have a wide range in which the distance is 1 μm or less, the contact area under the same load condition is increased, and the skew suppression effect is increased. In FIG. 9, since the chamfering of the roller large-diameter end surface and the rolling surface and the chamfering surface between the chamfering and the large-diameter end surface are not taken into consideration, a range of a distance of 1 μm or less extends to the roller contour. However, since chamfering and defacement surfaces are actually provided, the range of the distance of 1 μm or less is a slightly narrower range than FIG.

  Further, in Equation (2), the value of Rra is changed so that the curvature radius ratio Kr is 0.70 to 1.00, and the distance between the roller large-diameter end face and the large collar face is 1 μm or less. The area of was calculated. The specifications of the tapered roller bearing are as follows: β = 1.5 °, γ = 13.2 °, φ = 13.6 °, the outermost diameter of the inner ring raceway surface = 85 mm, and δ = 3.4 mm. did.

  Table 1 shows the calculation results, and FIG. 10 is a graph showing the relationship between the radius-of-curvature ratio Kr of the tapered roller bearing and the area where the distance between the roller large-diameter end surface and the large collar surface is 1 μm or less.

As can be seen from Table 1 and FIG. 10, when Kr ≧ 0.85, the contact area under the same load condition increases. Therefore, if Rra and δ are set so as to satisfy the relationship of Expression (3), the effect of suppressing skew is improved.
Kr = {Rra−δ / sin (β + γ−φ)} / (L / tanφ) ≧ 0.85 ――― (3)

As described above, according to the tapered roller bearing 10A of the present embodiment, the surface shape of the roller large-diameter end surface 22 is such that the circular arc D having the center O ₁ on the opposite side of the central axis C1 of the tapered roller 15A is conical. is formed by rotating the center axis C1 around the rollers 15A, rollers Rra the radius of the arc D of the large-diameter side end surface 22, the distance between the center O ₁ and the center axis C1 of the tapered roller 15A arc D [delta], roller diameter The distance from the contact point P between the end face 22 and the large collar surface 17 to the apex O ₃ of the conical surface of the large collar surface 17 is L, the half apex angle of the rolling surface of the tapered roller 15A is β, and the half apex of the inner ring raceway surface 13 When the angle is γ and the half apex angle of the conical surface of the large brim surface 17 is π / 2−φ, the relationship between the roller large diameter end surface 22 and the large brim surface 17 is satisfied by satisfying the relationship of the above formula (3). The contact area is increased, and skew can be effectively suppressed.

(Third embodiment)
Next, a tapered roller bearing according to a third embodiment of the present invention will be described with reference to FIGS. 11 and 12. In addition, the same code | symbol or an equivalent code | symbol is attached | subjected to the same or equivalent part as 1st Embodiment, and description is simplified or abbreviate | omitted.

  As described in the second embodiment, the wider the contact surface between the roller large-diameter end surface 22 and the large collar surface 17, or the higher the contact surface as viewed from the inner ring raceway surface 13, the more the skew of the tapered roller 15 </ b> A. The suppression effect becomes higher. In the tapered roller bearing 10A of the second embodiment, the contact surface between the roller large-diameter end surface 22 and the large collar surface 17 is widened in the circumferential direction to suppress skew, but the tapered roller bearing of the present embodiment. In 10B, the surface shape of the roller large-diameter end surface 22 is a combination of two types of curved surfaces, thereby forming a wide contact surface and suppressing skew.

As shown in FIGS. 11 and 12, the tapered roller bearing 10 </ b> B of the present embodiment is such that the shape of the roller large-diameter end surface 22 of the tapered roller 15 </ b> B has a center O ₁ at a position away from the roller center axis C 1 by δ _1. A rotation surface (aspherical surface) obtained by rotating the first arc D1 of Rr1 around the roller center axis C1 and a second arc D2 of radius Rr2 having a center O ₅ at a position separated by δ2 from the roller center axis C1. It is composed of a composite aspherical surface comprising a rotating surface (aspherical surface) rotated about the roller center axis C1. The centers O ₁ and O ₅ of the first and second arcs D1 and D2 are both on the opposite side of the first arc D1 and the second arc D2 with respect to the roller center axis C1.

  Therefore, as shown in FIG. 12, the composite aspherical surface of the roller large-diameter end surface 22 and the large brim surface 17 are in contact at two points P1 and P2 that are spaced apart in the radial direction. The surface shape of the outer edge on the side far from the roller center axis C1 is a rotating surface (aspheric surface) obtained by rotating the first arc D1 having the radius Rr1 around the roller center axis C1, and is close to the roller center axis C1. The surface shape of the central portion on the side is a rotating surface (aspherical surface) obtained by rotating the second arc D2 having the radius Rr2 around the roller central axis C1.

That is, the roller large end face 22, a roller connecting the large-diameter end face 22 at point P1 of the large rib surface 17, the radial curvature Rr1, and a circumferential curvature radius (points P1 and O ₄ lines has a length) Rc1 of, also, the roller and the large diameter end faces 22 in contact P2 of the large rib surface 17, the radial curvature Rr2, and a circumferential radius of curvature (point P2 and the point O ₆ The length of the connecting line) Rc2.

  In the tapered roller bearing 10B of the present embodiment, the roller large-diameter end face 22 has a surface shape of the roller large-diameter end face 22 that is a composite curved surface of two aspheric surfaces composed of the rotating surfaces of the first arc D1 and the second arc D2. 22 and the large brim surface 17 are brought into contact at two points P1 and P2, the contact surfaces at the points P1 and P2 are long in the circumferential direction, and the contact surface is widened to effectively skew the tapered roller 15B. Suppressed.

That is, as shown in FIG. 11, the half apex angle of the rolling surface 21 of the tapered roller 15 is β, the half apex angle of the inner ring raceway surface 13 is γ, and the half apex angle of the large collar surface 17 of the inner ring 14 is π / 2. -.phi, rollers δ1 central axis C1 from the center _O 1 of the first and second arc D1, D2, _{O 5} up to a distance of each, .delta.2, apex _{O 3} Karakoro large-diameter conical surface constituting the large rib surface 17 When the distances between the end surface 22 and the large brim surface 17 to the contacts P1 and P2 are L1 and L2, respectively, as in the second embodiment, the radii Rr1, δ1, and the radius so as to satisfy the relationship of Expression (4) By setting Rr2 and δ2, the contact surface between the roller large-diameter end surface 22 and the large brim surface 17 becomes longer in the circumferential direction, the contact area becomes wider, and skew can be effectively suppressed.

Krn = {Rrn−δn / sin (β + γ−φ)} / (Ln / tanφ) ≧ 0.85 (4)
However, n = 1, 2

  For example, paying attention to the rotating surface of the first arc D1 having the radius of curvature Rr1 formed on the side far from the roller center axis C1, the radius of curvature Rr1 is set to 0.70 to 1.00. The result of calculating the area in which the distance between the roller large-diameter end face and the large collar face is 1 μm or less by changing the value is the same as that of the tapered roller bearing 10B of the second embodiment shown in Table 1 and FIG. In addition, when Kr1 ≧ 0.85, the contact area under the same load condition increases. Therefore, if Rr1 and δ1 are set so as to satisfy the relationship of Expression (4), the skew can be effectively suppressed. However, the specifications of the tapered roller bearing used for the calculation are the same as the tapered roller bearing 10B of the second embodiment, β = 1.5 °, γ = 13.2 °, φ = 13.6 °, the inner ring raceway surface. The outermost diameter was 85 mm and δ was 3.4 mm.

  By similarly setting Rr2 and δ2 so as to satisfy the relationship of the formula (4), the rotation surface of the second arc D2 having the radius of curvature Rr2 formed in the central portion on the side close to the roller central axis C1 is also set. The effect of suppressing skew is improved.

As described above, according to the tapered roller bearing 10B of the present embodiment, the surface shape of the roller large-diameter end face 22 deviates from the roller center axis C1 within the cross section including the roller center axis C1 and the bearing center axis C2. A complex convex curved surface formed by rotating two arcs of the first arc D1 and the second arc D2 having the centers O ₁ and O ₅ at positions around the roller central axis C1, respectively, Since the roller large-diameter end face 22 of the tapered roller 15 contacts at two points, the skew can be effectively suppressed.

Further, the roller radius Rr1 of the first arc D1 of the large-diameter side end surface 22, the roller radius Rr2 of the second arc D2 of the large-diameter side end surface 22, the distance between the center _{O 1} at the center axis C1 of the first arc D1 .delta.1, the distance between the center _{O 5} at the central axis C1 of the second arc D2 .delta.2, the distance between the first arc D1 from the contact point P1 between the large rib surface 17 to the apex _{O 3} of the conical face of the large rib surface 17 L1, the and 2 arc D2 the distance from the contact point P2 to the vertex O ₃ of the conical face of the large rib surface 17 of the large rib surface 17 L2, the half apex angle of the rolling surface 21 of the tapered rollers 15 beta, the inner ring raceway surface 13 When the half apex angle is γ and the half apex angle of the conical surface of the large brim surface 17 is π / 2−φ,
{Rrn−δn / sin (β + γ−φ)} / (Ln / tanφ) ≧ 0.85 (n = 1, 2)
Therefore, the occurrence of skew can be suppressed, and heat generation due to friction between the roller large-diameter end surface 22 of the tapered roller 15 and the large collar surface 17 of the inner ring 14 due to the skew can be suppressed. Sticking can be prevented and high-speed rotation performance is improved.

  In addition, this invention is not limited to each embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.

10, 10A, 10B Tapered roller bearing 11 Outer ring raceway surface 12 Outer ring 13 Inner ring raceway surface 14 Inner ring 15 Tapered roller (rolling element for tapered roller bearing)
17 Large collar surface 21 Rolling surface 22 Roller large-diameter end surface C1 Roller center axis C2 Bearing center axis (rotary shaft of tapered roller bearing)
D Arc D1 First arc (arc)
D2 Second arc (arc)
Kr Curvature radius ratio L Distance from the contact point between the large roller end face and the large brim surface to the apex of the conical surface of the large brim surface L1 From the contact point of the first arc to the large brim surface to the apex of the conical surface of the large brim surface Distance L2 Distance from the contact point between the second arc and the large brim surface to the apex of the conical surface of the large brim surface O ₁ Arc center O ₃ Conical apex Rr1 Radial curvature radius of the first arc (the first arc radius)
Rr2 Radius of curvature of the second arc (radius of the second arc)
Rra The radius of curvature of the large diameter end face of the roller (radius of the arc)
Rca The radius of curvature of the roller large diameter end surface in the circumferential direction Rrb The radius of curvature of the large collar surface in the radial direction Rcb The radius of curvature of the large collar surface in the circumferential direction β The half apex angle γ of the rolling surface of the rolling element The half of the inner ring raceway surface Vertex angle δ Distance from the center of the arc to the center axis δ1 Distance from the center of the first arc to the center axis δ2 Distance from the center of the second arc to the center axis π / 2-φ Half-top of the conical surface of the large brim Corner

Claims (3)

  A rolling element for a tapered roller bearing, comprising a roller large-diameter end surface having a surface shape obtained by rotating an arc having a center of curvature away from the roller center axis around the roller center axis.   The rolling element for a tapered roller bearing according to claim 1, wherein a surface shape of the roller large-diameter end surface is a torus surface. An outer ring having an outer ring raceway surface on the inner circumferential surface;
An inner ring having an inner ring raceway surface on the outer peripheral surface;
A plurality of rolling elements according to claim 1, wherein the rolling elements are arranged so as to be freely rollable between the outer ring raceway surface and the inner ring raceway surface;
A tapered roller bearing, wherein a large collar surface of the inner ring that contacts a roller large-diameter end surface of the rolling element is a conical surface having a center on a rotating shaft of the tapered roller bearing.

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