JP2009019701A - Split type needle roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a needle roller bearing which reduces the adverse effect of a level difference made at a joint portion of a divided race ring and prevents the occurrence of noise and flaking. <P>SOLUTION: The needle roller bearing 10 whose outer ring 12 is circumferentially divided into at least two parts is characterized in that a flank 12e different in shape from an inner diameter face 12a is provided at a circumferential end portion of the inner diameter face 12a of the divided outer ring 12 and that the flank 12e and the inner diameter face 12a are continued through a curved surface. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a needle roller bearing in which a bearing ring and a cage are divided at least in the circumferential direction. For example, a split needle used in a rotating portion of a crankshaft or a connecting rod of an automotive engine or industrial machine. The present invention relates to a tapered roller bearing.

  Conventionally, as a bearing for supporting a crankshaft of an automobile engine, a split sliding bearing divided into two has been mainly used due to restrictions on assembly. However, the split type plain bearing has a high frictional resistance under high speed rotation. For this reason, in recent years, there has been a movement to improve fuel efficiency by adopting needle roller bearings with low frictional resistance.

Here, when the bearing ring and the cage of the needle roller bearing are divided into two to form the split roller bearing, for example, an integral bearing ring as described in Patent Document 1 is formed on the center line by a method of “natural split”. The method of cutting is taken.
JP-A-6-81846

  However, in the above method, as shown in FIG. 5, in the bearing 40 that supports the shaft 44, it is inevitable that a step in units of microns occurs at the joint portion of the outer ring 42 that is a divided raceway ring. In the case where the housing to be divided is a split type, a deviation at the time of assembling the upper and lower housings is superimposed as a step on the outer ring dividing surface. Therefore, at the joint of the outer ring 42, there is a problem that noise is generated due to the collision between the roller 41 and the edge 42 c at the end of the inner diameter surface 42 a of the outer ring 42, and flaking occurs from the same part. In FIG. 5, the level difference at the joint of the outer ring 42 is exaggerated.

  An object of the present invention is to provide a needle roller bearing that reduces the influence of a step generated at a joint portion of a split raceway ring and prevents noise and flaking.

The above object of the present invention can be achieved by the following constitution.
(1) In the needle roller bearing in which the outer ring is divided at least in the circumferential direction, a flank having a shape different from the inner diameter surface is provided at a circumferential end of the inner diameter surface of the divided outer ring. A needle roller bearing characterized in that the inner surface is continuous through a curved surface.

(2) The needle roller bearing according to (1), wherein the flank is a curved surface having a smaller radius of curvature than the radius of the roller.

  According to the configuration of (1), the step at the joint portion of the divided outer ring is made flat by providing the flank having a shape different from that of the inner surface at the circumferential end of the inner surface of the outer ring. The rollers do not collide with the step at the end of the inner diameter surface. Further, since the flank and the inner surface are continuous via the curved surface, the rollers are guided without impact by the curved surface when returning to the inner surface after escaping along the flank. Therefore, the impact when the roller rolls the joint portion of the outer ring is reduced and flaking is prevented.

  According to the configuration of (2), since the flank is a curved surface having a smaller radius of curvature than the radius of the roller, the roller does not enter the deepest part of the flank and the roller contacts the step of the joint. Absent.

  According to the split needle roller bearing of the present invention, when the roller rolls on the stepped portion at the joint portion of the divided outer ring, the impact is reduced, so that generation of noise and flaking can be prevented. it can.

  The split roller bearing obtained by the present invention is suitably used for supporting a crankshaft of an automobile engine when low vibration, high load resistance, and high durability are required.

Hereinafter, the present invention will be described with reference to illustrated embodiments.
FIG. 1A is a cross-sectional view of a split needle roller bearing according to the first embodiment of the present invention, and FIG. 1B is an enlarged view of a portion A in FIG.

  Referring to FIG. 1, a split needle roller bearing 10 includes a plurality of needle rollers 11 arranged in the circumferential direction, and an annular outer ring having an inner diameter surface 12 a as a raceway surface of each roller 11 on the inner periphery. The bearing ring 12 is disposed on the inner peripheral side of the outer ring 12, and includes a cage (not shown) that holds each roller 11 in a rollable manner, and a shaft 14 that functions as an inner ring. The shaft 14 is, for example, a crankshaft of an automobile engine, and the split needle roller bearing 10 is used as a bearing that supports the crankshaft 14. In the split needle roller bearing 10, the outer ring 12 and the cage are equally divided into two in the circumferential direction, and the end surfaces in the circumferential direction are joined to each other.

  A flank 12 e made of a chamfered surface is formed at the circumferential end of the inner diameter surface 12 a of the outer ring 12. The flank 12e is provided after dividing the outer ring. The angle θ between the flank 12e and the radial direction at the circumferential end 12b of the outer ring 12, that is, the chamfer angle θ is 60 ° to 70 °. The flank 12e and the inner diameter surface 12a are continuous via a curved surface 12f having a curved surface radius R.

  By forming a relief surface 12e by chamfering at the circumferential end of the inner diameter surface 12a of the outer ring 12, even when a radial deviation occurs in the joint portion of the outer ring 12, the deviation is a roller 11 having a curvature radius R2. Therefore, the edge 12c of the stepped portion 11 caused by the deviation does not interfere with each other. Further, since the roller 11 smoothly passes through the chamfered slope and the curved surface continuous with the slope to reach the inner diameter surface 12a, the impact is reduced.

  When the chamfering angle θ is smaller than 60 °, the rolling inclination of the roller 11 becomes tight, and the wedge effect between the outer ring chamfered portion and the shaft acts greatly. Moreover, since the amount of falling into the chamfer increases, there is a possibility that the rotation of the roller 11 is obstructed. On the other hand, if the chamfering angle θ is larger than 70 °, the escape space is narrowed, and the deviation generated in the divided portion cannot be allowed.

  FIG. 2 shows a second embodiment of the present invention, which is an example in which a curved surface having a radius of curvature R1 smaller than the radius of the roller 11 is provided as the flank 12e. The flank 12e and the inner diameter surface 12a are continuous via a curved surface. As shown in FIG. 2, when the radius of curvature R1 of the curved surface is made smaller than the radius R2 of the roller 11, the roller 11 does not enter the concave portion formed by the curved surface, and collides with the edge 12c of the step generated in the divided portion. Can be avoided. Further, since the flank 12e and the inner diameter surface 12a are continuous via the curved surface, the roller 11 smoothly moves from the flank 12e to the inner diameter surface 12a, and the impact is reduced.

  On the other hand, as shown in FIG. 3, when the radius of curvature R3 of the flank 12e is larger than the radius R2 of the roller 11, the roller 11 enters the deepest part of the flank that is a concave formed by a curved surface, and there is no flank. Similarly, the roller 11 collides with the step edge 12c to cause a problem of noise and flaking due to impact. However, even in the configuration of FIG. 3, the roller 11 can be moved smoothly by making the circumferential tip of the flank 12 e a curved surface and a continuous shape through the inner surface and the curved surface. The impact when 11 passes a division part can be reduced.

  FIG. 4 shows a split needle roller bearing according to a second embodiment of the present invention. In the case of this bearing, the flank 12g is formed by curving the end portion of the inner diameter surface 12a to have a curved surface convex toward the roller 11, and the radius of curvature R4 of the flank 12g is larger than the radius of the roller 11. small.

  As described above, since the end portion of the inner diameter surface 12a is a curved surface, the roller 11 does not collide with the edge when passing through the divided portion, so that the impact is reduced. Further, since the radius of curvature R4 of the flank 12g is smaller than the radius of the roller 11, the roller 11 does not enter the deepest part of the flank that is a recess formed by the flank 12g. Can be moved to.

  As described above, according to the above embodiment, the step at the joint portion of the divided outer ring approaches the flat surface by providing the relief surface having a shape different from the inner diameter surface at the circumferential end of the inner diameter surface of the outer ring. As a result, the roller does not collide with the step when rolling the joint portion of the outer ring, and the impact is reduced and flaking is prevented.

(A) is sectional drawing which shows the split-type roller bearing which is 1st Embodiment of this invention, (b) is the A section enlarged view of (a). (A) is sectional drawing of the modification of a split roller bearing, (b) is the B section enlarged view of (a). (A) is sectional drawing of the other modification of a split type roller bearing, (b) is the C section enlarged view of (a). (A) is sectional drawing which shows the split-type roller bearing which is 2nd Embodiment of this invention, (b) is the E section enlarged view of (a). (A) is sectional drawing of the conventional split roller bearing, (b) is the D section enlarged view of (a).

Explanation of symbols

10, 40 Bearing 11, 41 Roller 12, 42 Outer ring 12a Inner diameter surface 12b End surface 12c Edge 12e, 12g Relief surface 12f Curved surface 14, 44 Shaft

Claims (2)

  In the needle roller bearing in which the outer ring is divided at least in the circumferential direction, a flank having a shape different from the inner diameter surface is provided at the circumferential end of the inner diameter surface of the divided outer ring. Is a needle roller bearing characterized by being continuous through a curved surface.   The needle roller bearing according to claim 1, wherein the flank is a curved surface having a smaller radius of curvature than the radius of the roller.

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