JP2951036B2 - Tapered roller bearing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tapered roller bearing having a tapered roller incorporated between an outer ring and an inner ring.

[0002]

2. Description of the Related Art As shown in FIG.
There is a tapered roller bearing in which the large end face 24 of the tapered roller 23 incorporated between the tapered roller 23 and the large end face 24 is guided by a large collar 25 formed on the inner race 21.

The vertices of the cones of the inner ring 21, the outer ring 22, and the rollers 23 are designed to coincide with one point O on the center line L of the bearing, and the radius R of the circumference serving as the roller contact point of the large collar 25 is set.
Is also designed to have a length centered on the point O. Roller 2
The radius of curvature R1 of the large end face 24 of the No. 3 is designed to be slightly shorter than the above-mentioned flange radius R, and the center of curvature O1 is located closer to the point O.

[0004]

The large end face 24 of the roller 23
The contact state between the inner ring 21 and the large brim 25 is a point contact when there is no load, but when a thrust load is applied, FIG.
The contact surface becomes an elliptical contact as shown by a shaded portion. The shape of the contact ellipse A changes depending on the relationship between the collar radius R and the roller end face radius R1 as follows.

When the difference between the flange radius R and the large end face radius R1 is small, the major axis of the contact ellipse A becomes longer as shown in FIG. Therefore, when the applied load is large, the contact ellipse A may exceed the roller large end face 24 and extend to the chamfered portion 26 on the outer peripheral edge. When extending to the chamfered portion 26 in this manner, stress concentrates on the edge portion 27 between the large end surface 24 and the chamfered portion 26, the oil film is cut off at the edge portion 27, galling occurs, and seizure occurs. There is.

FIG. 9 shows a case where the radius R1 of the roller large end surface is shortened. In this case, although the major axis of the contact ellipse A is shortened, the restoring force in the case where the roller 23 is tilted as shown in FIG. When the skew occurs in this manner, a sticking phenomenon occurs, and even if the major axis of the contact ellipse A is short, the position of the contact ellipse A is biased to reach the edge portion 27 as shown by a chain line in FIG. Burning due to cutting is caused.

An object of the present invention is to provide a tapered roller bearing which can provide a restoring force when skew occurs, can shorten the major axis of the contact ellipse, and can prevent seizure. is there.

[0008]

In the tapered roller bearing of the present invention, the radius of curvature of the portion near the chamfered portion, which is the portion near the outer peripheral edge of the large roller end surface, is gradually reduced as approaching the outer diameter side.

In the bearing of the second aspect, in the configuration of the first aspect, the radius of curvature of a portion closer to the center than the portion near the chamfered portion of the roller large end face is set to be 70 to the radius of the roller contact point of the guide flange.
And a radius of curvature at the intersection of the portion near the chamfered portion and the chamfered portion is 5 to the radius of the roller contact.
It has a length of 0 to 70%.

[0010]

According to the above construction, since the radius of curvature of the portion near the chamfered portion of the roller large end face is shortened, the major axis of the contact ellipse with the roller guide collar is shortened, and even if a large load is applied, the contact ellipse is reduced. It does not extend to the chamfer. Since the radius of curvature gradually decreases, even if the radius of curvature changes in the middle of the large end face, the problem of oil film breakage does not occur. In addition, the restoring force against skew can be favorably obtained in a portion having a longer radius of curvature on the center side than a portion near the chamfered portion of the roller large end surface.

When the relationship between the radii of the respective parts is set in the above range, the effects of preventing skew and shortening the long axis of the contact ellipse can be obtained in the most balanced and effective manner.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 2, tapered roller bearings
It comprises an inner ring 1, an outer ring 2, a tapered roller 3, and a retainer 4 for holding the tapered roller 3. On the outer diameter surface of the inner ring 1,
A large brim 5 for guiding the rollers 3 and a small brim 6 for retaining the rollers are provided. The roller contact surface of the large brim 5 is formed as a conical surface, but may be a spherical surface.

The vertices of the cones of the inner ring 1, the outer ring 2 and the rollers 3 are designed to be concentrated at one point on the center line of the bearing, as in the example of FIG. The circumference radius R (FIG. 1) is also designed to be centered at the point.

The roller 3 has a large end surface 7 formed into a spherical surface, a recessed recess 8 formed at the center thereof, and a chamfered portion 9 having an arc-shaped cross section formed at the outer peripheral edge. A portion B of the large end face 7 between the recessed concave portion 8 and the chamfered portion 9 is polished to make the contact with the large brim 5 smooth.

The grinding portion B of the large end face 7 is formed by moving a portion 10 closer to the center of the roller than the center position P of the width of the grinding portion to a radius of curvature Ra.
It is formed in the spherical surface. The radius of curvature Ra is 70 with respect to the radius R of the large brim 5 (hereinafter, referred to as “brim radius R”).
９０90% (that is, 70% or more and 90% or less).

The portion 11 near the chamfered portion of the large end face 7 from the central portion P of the grinding portion to the chamfered portion 9 is formed so that the radius of curvature Rb is gradually reduced as it approaches the outer diameter side from the central portion P of the grinding portion. In addition, at the intersection Q with the chamfered portion 9, the length is set to 50 to 70% of the radius R of the collar. At the grinding portion center position P, the radius of curvature Rb becomes the same as the radius of curvature Ra.

According to this configuration, the central portion 10 of the large end face 7 of the roller 3 is formed with a curvature radius Ra close to the flange radius R.
Therefore, due to the contact between the central portion 10 and the large brim 5, a good restoring force against the skew of the rollers 3 can be obtained.

Further, since the radius of curvature Rb of the portion 11 near the chamfered portion is gradually reduced, the contact ellipse A with the large brim 5 as shown in FIG. And the major axis becomes shorter. Therefore, even if a large load is applied, the contact ellipse A does not extend to the chamfered portion 9. Therefore, the occurrence of oil film shortage is prevented, and the problem of burn-in is solved. Since the radius of curvature Rb is gradually reduced, no edge portion is generated, and the problem of oil film shortage due to a change in the radius of curvature Rb does not occur.

As a result of various experiments, the radius of curvature Ra of the roller large end face 7 was set to 70 to 90 with respect to the collar radius R as described above.
% And the radius of curvature Rb of 50 to 70% at the intersection 9, the effect of preventing skew and preventing image sticking by shortening the contact ellipse A was obtained in the most balanced and effective manner.

In the above embodiment, the portion 1 near the chamfered portion is used.
The boundary position between the center portion 1 and the center side portion 10 is defined as the grinding portion center position P, but this boundary position can be arbitrarily determined.

In the above embodiment, a radial tapered roller bearing has been described as an example, but as shown in FIG. 4, a thrust tapered roller bearing in which a tapered roller 14 is incorporated between an outer ring 12 and an inner ring 13 with a flange. Alternatively, as shown in FIG. 5, in a thrust tapered roller bearing in which a tapered roller 17 is incorporated between a flanged outer ring 15 and a flanged inner ring 16,
The present invention can be applied.

[0022]

According to the tapered roller bearing of the present invention, the radius of curvature of the portion near the chamfered portion of the roller large end surface is gradually reduced as approaching the outer diameter side, so that the major axis of the contact ellipse with the guide collar is shortened. Therefore, even if a large load is applied, the oil film does not break, and seizure can be prevented. In addition, the restoring force against skew can be favorably obtained in a portion having a longer radius of curvature on the roller center side than the portion near the chamfered portion. When the relationship between the radii of the respective parts is set in the range defined in claim 2, the above-described effect of preventing skew and preventing image sticking by shortening the long axis of the contact ellipse can be obtained with the best balance.

[Brief description of the drawings]

FIG. 1 is a partially enlarged sectional view of a tapered roller bearing according to one embodiment of the present invention.

FIG. 2 is a sectional view of the tapered roller bearing.

FIG. 3 is an explanatory view showing a contact state between the tapered rollers and the large brim.

FIG. 4 is a sectional view of another embodiment of the present invention.

FIG. 5 is a sectional view of still another embodiment of the present invention.

FIG. 6 is a sectional view of a conventional tapered roller bearing.

FIG. 7 is an explanatory diagram of the operation.

FIG. 8 is an explanatory diagram showing a contact state between a tapered roller and a large brim in a predetermined dimensional relationship in the conventional example.

FIG. 9 is an explanatory view showing a state of contact between a tapered roller and a large brim in a dimensional relationship different from that of FIG. 8 of the conventional example.

FIG. 10 is an explanatory diagram of the skew state.

[Explanation of symbols]

1 ... inner ring, 2 ... outer ring, 3 ... tapered rollers, 5 ... large brim, 7
... Large end face, 8 ... Recessed recess, 9 ... Chamfered part, 10 ... Center side part, 11 ... Chamfered part vicinity, A ... Contact ellipse

Claims (2)

(57) [Claims] 1. A large end face of a tapered roller incorporated between an inner ring and an outer ring has a spherical surface, and a chamfered portion is provided on an outer peripheral edge of the large end face, and a guide flange of the tapered roller is provided on at least one of the two wheels. The tapered roller bearing according to claim 1, wherein a radius of curvature of a portion near a chamfered portion of said roller large end surface is gradually reduced as approaching an outer diameter side. 2. A radius of curvature of a portion closer to the center than a portion near the chamfered portion of the roller large end surface is set to be 70 to 90% of a radius of a contact of the guide rib roller, and a portion near the chamfered portion and the chamfered portion are formed. 2. The tapered roller bearing according to claim 1, wherein the radius of curvature at the intersection of the lengths is 50 to 70% of the radius of the roller contact.