Development of new structure anti-creep ball bearing

JTEKT Corporation (hereinafter called “JTEKT”) has newly created a tagline “Key of your operation Koyo” for the bearing brand “Koyo”. JTEKT contributes to every industry as an indispensable partner to solve customers' problems through working with customers and to provide benefits.
JTEKT has developed a new structure anti-creep ball bearing intended for use mainly in automotive transmissions.
For this developed product, we achieved the suppression of creep (phenomenon that the outer ring rotates on the housing) as a measure for life shortening of the housing and bearing due to wear, instead of thickening the outer ring, which was the conventionally general approach. This product contributes to the reduction in weight and size of automotive transmissions, etc.
We are going to expand the sales of this product as a bearing for automotive transmissions such as CVT and HV to automotive manufacturers and transmission manufacturers, as well as to a wide range of applications which require the suppression of creep.

1.Feature

(1) This developed product has the world’s first anti-creep structure and shape against a creep due to a strain of the outer ring (*Internal investigation)

(2) Creep reduction equivalent to an increase in bearing thickness by 35% (Example: housing wear is reduced by 50%)

(3) Contributes to the reduction in the weight and size of transmissions, etc. by replacing conventional bearings

2.Detailed description

The bearings affected by large radial load, such as the ball bearings for transmissions of automobiles (especially, CVT or HV) have a characteristic that creep (phenomenon that the outer ring rotates on the housing) easily occurs due to the strain of the outer ring. When the creep occurs, the wear progresses between the bearing and housing, leading to the misalignment and slant of the axis. This may cause a failure in the actual machine unit.

The outer ring thickening is a countermeasure generally taken against the creep occurrence due to the outer ring strain. However, this countermeasure has the problem that the actual machine unit becomes larger and heavier along with the bearing size increase. (Refer to figure)
In this developed product, we adopted the world’s first structure that has an extremely thin groove on the middle part of outer diameter of outer ring so that the distance from the contact point of the ball and outer ring raceway to the contact part of the outer ring outer diameter and housing is equal to that of the outer ring thickened product. By utilizing this structure, we succeeded in suppressing the creep to a level equivalent to that of a product with a 35% thicker outer ring. Thus, the abovementioned problem was solved. (Refer to figure)
This developed product eliminated the necessity for conventional thickening of the outer ring. As a result, it became possible to reduce the weight and size of automotive transmissions, etc.

3.Sales plan

4.Production plant

Ball bearing production plant in Japan and overseas