JP2015064010A - Tapered roller bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tapered roller bearing in which an outer ring is inexpensively manufactured, and which is excellent in load resistance.SOLUTION: An outer ring 5 is formed by press-working a steel plate, and shapes of axial-direction cross sections of a raceway surface 5a of the outer ring and an external peripheral face 10a of a tapered part 10 having the raceway surface 5a are formed so as to coincide with a shape of an axial-direction cross section of a convex shape of a tapered face 2b of a housing 2 when the outer ring 5 is attached to the internal peripheral surface 2a of the housing 2. By this constitution, during the operation of a bearing, a shape of the outer ring raceway surface 5a is substantially formed into a crowning shape as desired by a designer, face pressure acting on the outer ring 5 is equalized, excellent load resistance can be obtained, cutting work and grinding work necessary for conventional manufacturing of the outer ring are dispensed with, and a manufacturing cost of the outer ring 5 can be reduced.

Description

  The present invention relates to a tapered roller bearing that can be manufactured at low cost.

  Tapered roller bearings are widely used as rolling bearings suitable for simultaneously supporting large radial loads and thrust loads. The general structure is that an inner ring having a tapered raceway surface on the outer peripheral surface, an outer ring having a tapered raceway surface on the inner peripheral surface, and a plurality of cones incorporated between the raceway surfaces of these both raceways. A roller and a cage for holding each tapered roller in a rollable manner. A large flange is integrally formed at the large-diameter side end of the inner ring and a small flange is integrally formed at the small-diameter side end. I try not to fall off.

  In such a conventional tapered roller bearing, when manufacturing an outer ring, usually a forging process, a cutting process, a heat treatment and a grinding process are sequentially performed using a lump of steel material as a raw material. Increases manufacturing costs.

  Therefore, the present applicant has proposed that the outer ring is formed by pressing from a steel plate, thereby eliminating the need for cutting and grinding during the production of the conventional outer ring and reducing the production cost of the outer ring ( (See Patent Document 1).

  Moreover, in patent document 1, the axial cross-sectional shape of the raceway surface of the outer ring | wheel formed by press work from a steel plate is formed in a convex shape (convex curve shape), and the surface pressure which acts on an outer ring at the time of bearing operation is equalized. It has also been proposed to improve the load bearing performance by reducing the surface pressure received from the roller edge. In order to avoid the generation of excessive contact surface pressure due to stress concentration between the edges of the raceway surface in this way, making the axial cross-sectional shape of the raceway surface convex is generally called “crowning” The shape is often called “crowning shape”.

JP 2013-36596 A

  By the way, when the tapered roller bearing described in Patent Document 1 is attached to the housing, the tapered portion of the outer ring having the raceway surface on the inner peripheral surface is in contact with the linear tapered surface formed on the inner peripheral surface of the housing. It has become. For this reason, when the outer ring raceway surface is crowned as described above, if the axial cross-sectional shape of the outer circumferential surface of the outer ring taper portion is also convex like the raceway surface, the outer circumference of the convex shape during bearing operation The outer ring is deformed so that the surface follows the linear tapered surface of the inner circumference of the housing, the outer ring raceway surface shape deviates from the crowning shape intended by the designer, and the contact surface pressure between the outer ring raceway surface and the rolling surface, In particular, the edge surface pressure becomes excessive, and there is a possibility that sufficient load bearing performance cannot be obtained.

  On the other hand, if the outer peripheral surface shape of the tapered portion of the outer ring is a linear taper, the deformation of the outer ring during bearing operation is reduced, and the shape of the outer ring raceway surface becomes a crowning shape almost as intended by the designer. Load bearing performance can be secured. However, since it is difficult to form an outer ring with such a shape from a steel plate with a constant plate thickness by pressing, it can be formed by pressing or cutting a steel plate with a constant plate thickness. It becomes necessary and the cost reduction effect is small.

  Therefore, an object of the present invention is to provide a tapered roller bearing that can manufacture an outer ring at low cost and is excellent in load bearing performance.

  In order to solve the above-mentioned problems, the present invention incorporates a plurality of tapered rollers between the tapered raceway surfaces of the inner ring and the outer ring, and each of these tapered rollers is rotatably held by a cage. In the roller bearing, the outer ring is formed by pressing a steel plate, and the axial cross-sectional shapes of the raceway surface of the outer ring and the outer peripheral surface of the tapered portion having the raceway surface are such that the outer ring is formed inside the housing. The structure formed so that it might correspond with the convex axial cross-sectional shape of the taper surface formed in the inner peripheral surface of the said housing when it attached to the surrounding surface was employ | adopted.

  According to the above configuration, deformation of the outer ring during bearing operation is suppressed, and the shape of the outer ring raceway surface becomes a crowning shape as intended by the designer, so that the surface pressure acting on the outer ring is made uniform and resistant to damage. The load performance can be improved, and the outer ring can be formed from a steel plate having a constant thickness only by pressing. Therefore, the cutting and grinding processes in the conventional outer ring manufacturing are not required, and the manufacturing cost of the outer ring can be reduced.

  Further, if the outer diameter of the outer ring is formed larger than the inner diameter of the housing and the outer ring is attached to the inner peripheral surface of the housing in an elastically deformed state, the outer ring and the housing Since it becomes difficult to generate a gap between them, a change in the crowning shape of the outer ring raceway surface due to the intrusion or biting of foreign matter into the gap can be prevented, and the load bearing performance can be stably maintained.

  The steel plate used as the material of the outer ring may have a carbon content of 0.8 mass% or more from the viewpoint of wear resistance and ease of heat treatment.

  As described above, the tapered roller bearing of the present invention is formed by pressing the outer ring from a steel plate, and the axial cross-sectional shape of the outer ring raceway surface and the outer peripheral surface of the tapered portion having the raceway surface, When the outer ring is attached to the inner peripheral surface of the housing, it is formed so as to match the convex axial cross-sectional shape of the tapered surface of the inner periphery of the housing. It can be manufactured at low cost without the need for cutting or grinding.

Longitudinal front view of the tapered roller bearing of the embodiment in the assembled state 1 is a longitudinal front view showing a method for mounting the outer ring of FIG. 1 to a housing. Longitudinal front view showing a modified example of the method of attaching the outer ring to the housing

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a state in which the tapered roller bearing 1 of the embodiment is assembled between the housing 2 and the rotating shaft 3. The tapered roller bearing 1 includes an inner ring 4 having a tapered raceway surface 4a on an outer peripheral surface, an outer ring 5 having a tapered raceway surface 5a on an inner peripheral surface, and raceway surfaces 4a of both the raceways 4 and 5. 5a, a plurality of tapered rollers 6 incorporated between 5a, and a retainer 7 that holds each tapered roller 6 in a rollable manner, and a large flange 8 is provided at the large-diameter side end of the inner ring 4 at the small-diameter side end. A gavel 9 is integrally formed so that the tapered roller 6 and the cage 7 do not fall off from the inner ring 4. The inner ring 4 is fitted on the outer peripheral surface of the rotating shaft 3, and the outer ring 5 is attached to the inner peripheral surface of the housing 2.

  The outer ring 5 is formed by press working from a hot-rolled steel plate or a cold-rolled steel plate having a constant plate thickness. The material of the steel plate used as the material is one having a carbon content of 0.8 mass% or more, for example, high carbon chromium bearing steel (SUJ2 specified by JIS) or carbon tool steel (SK4, SK5 specified by JIS). ). The reason for selecting this material is that it has excellent wear resistance, which is a necessary property of bearings, has a large distribution volume, is inexpensive in steel materials, and has a high carbon content. (Submerged quenching) provides the same level of hardness distribution as before.

  The outer ring 5 includes a tapered portion 10 whose inner peripheral surface is a raceway surface 5 a, a flange portion 11 that extends radially outward from the large-diameter end of the tapered portion 10, and a small-diameter end of the tapered portion 10. It consists of the straight cylinder part 12 extended in an axial direction. The axial cross-sectional shapes of the raceway surface 5a and the outer peripheral surface 10a of the tapered portion 10 are the same as those in FIG. 1, that is, when the outer ring 5 is attached to the inner peripheral surface 2a of the housing 2. It is formed so as to coincide with the convex axial cross-sectional shape of the tapered surface 2b formed on 2a.

  Further, as shown in FIG. 2, the outer ring 5 is formed such that the outer diameter on the small diameter side is larger than the inner diameter on the small diameter side of the housing 2 by δ before being attached to the inner peripheral surface 2 a of the housing 2. Then, by pressing the outer ring 5 into the inner periphery of the housing 2 from the state of FIG. 2, the outer ring 5 is attached to the inner peripheral surface 2a of the housing 2 in an elastically deformed state, and the raceway surface 5a of the outer ring 5 as described above. The axial sectional shape of the outer peripheral surface 10a of the tapered portion 10 and the axial sectional shape of the tapered surface 2b of the inner periphery of the housing 2 are made to coincide with each other.

  The tapered roller bearing 1 has the above-described configuration, and the axial cross-sectional shape of the raceway surface 5a of the outer ring 5 and the outer peripheral surface 10a of the tapered portion 10 is the tapered surface 2b of the inner periphery of the housing 2 during the bearing operation. Therefore, the deformation of the outer ring 5 is suppressed and the shape of the outer ring raceway surface 5a becomes a crowning shape as intended by the designer. As a result, the surface pressure acting on the outer ring 5 is reduced. Excellent load-carrying performance is obtained by homogenization. In addition, since the outer ring 5 can be formed from a steel plate having a certain thickness only by pressing, it is possible to manufacture the outer ring 5 at a low cost without the need for cutting or grinding during the production of the outer ring.

  In addition, the outer ring 5 is pressed into the inner peripheral surface 2a of the housing 2 and attached in an elastically deformed state so that a gap is less likely to be formed between the outer ring 5 and the foreign matter entering or biting into the gap. The change of the crowning shape of the outer ring raceway surface 5a due to can be prevented, and the load bearing performance can be stably maintained.

  FIG. 3 shows a modification of the method for attaching the tapered roller bearing 1 to the housing 2. In this modification, after the outer ring 5 is press-fitted into the inner peripheral surface 2 a of the housing, a bolt 13 is screwed into the housing 2 through a bolt hole 11 a opened in the flange portion 11 of the outer ring 5. As a result, the outer ring 5 can be prevented from rotating with respect to the housing 2 and at the same time can be prevented from coming off, so that the tapered roller bearing 1 can be used more stably.

DESCRIPTION OF SYMBOLS 1 Tapered roller bearing 2 Housing 2a Inner peripheral surface 2b Tapered surface 3 Rotating shaft 4 Inner ring 4a Raceway surface 5 Outer ring 5a Raceway surface 6 Tapered roller 7 Cage 8 Large flange 9 Small flange 10 Tapered portion 10a Outer peripheral surface 11 Flange portion 12 Straight cylinder portion 13 volts

Claims (3)

In a tapered roller bearing in which a plurality of tapered rollers are incorporated between the tapered raceway surfaces of the inner ring and the outer ring, and each of these tapered rollers is rotatably held by a cage.
The outer ring is formed by pressing a steel plate, and the axial cross-sectional shape of the outer ring raceway surface and the outer peripheral surface of the tapered portion having the raceway surface is attached to the inner peripheral surface of the housing. A tapered roller bearing formed so as to coincide with a convex axial cross-sectional shape of a tapered surface formed on an inner peripheral surface of the housing.   2. The tapered roller according to claim 1, wherein an outer diameter of the outer diameter of the outer ring is larger than an inner diameter of the outer diameter of the housing, and the outer ring is attached to the inner peripheral surface of the housing in an elastically deformed state. bearing.   The tapered roller bearing according to claim 1 or 2, wherein the steel plate used as the material of the outer ring has a carbon content of 0.8 mass% or more.

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