Development and volume-production of the High Ability Series “grease-lubricated angular contact ball bearing with low temperature-rise” for machine tool spindles

JTEKT Corporation (hereinafter JTEKT) has developed the “grease-lubricated angular contact ball bearing with low temperature-rise”, with the aim of improving the performance of the “High Ability Series” bearing for machine tool spindles, by optimizing the cage shape to suppress the temperature-rise during rotation and started the volume-production. This developed product contributes to the improvements in the production efficiency in assembling machine tool spindles, machining accuracy and bearing replacement intervals.

1.Background of development

Bearings for machine tool spindles are required to keep the temperature-rise low since the temperature-rise on the spindle causes the thermal expansion of the spindle and possibly deteriorates the machining accuracy.
Additionally, grease lubrication, which is widely adopted as a bearing lubrication method for reasons of easy handling and simplification of the spindle structure, requires a trial run (breaking-in) to smooth the grease when the spindle is assembled. Thus reducing the time required for the breaking-in has been an issue in regards to improving the production efficiency.
We reviewed the bearing design and have succeeded in developing a product responding to these issues.

2.Features of the developed product

The developed product realized low temperature-rise and reduction of the time required for the breaking-in with:

(1) Optimized cage pocket shape and
(2) Optimized clearance between the inner ring and cage.

[Structural figure of planetary carrier]

3.Sales plan

4.Production plant

Kokubu Plant

JTEKT Corporation has newly created a tagline “Key of your operation Koyo” for the bearing brand “Koyo”. JTEKT will continue contributing to every industry including machine tools as an indispensable partner to solve customers' problems through working with customers and to provide benefits.