US 5,344,238 A · Ball bearing assembly

Abstract

The ball bearing assembly has a total stroke range comprising a first portion where a clearance fit is applied and a second range where an interference fit is applied. The interference stroke range is used to, for example, carry a platform where precise alignment is necessary, and deflections or other movement of the platform must be minimized. Use of the ball bearing assembly to carry a platform holding a semiconductor wafer to be probed is illustrated. After each wafer is probed, the ball cage is reset such that any migration of the ball cage is eliminated so that the clearance and interference stroke ranges return to predetermined values. Further provided are means for rotationally resetting the ball cage, providing for even wear over the entire surfaces of the shaft and housing in their working zones to increase the useful lifetime of the assembly. Also provided are means for maintaining a predetermined interference fit over an extended temperature range, even where the shaft and housing operate at different temperatures.

Claims16

Dependent claims

A ball bearing assembly comprising:

a housing;
a shaft disposed in said housing;
retaining means for retaining balls, said retaining means disposed between said shaft and said housing;
a plurality of balls disposed in said retaining means;
wherein said ball bearing assembly has a total stroke range of said shaft relative to said housing comprising a first stroke range and a second stroke range, said first stroke range having a clearance fit, and said second stroke range having an interference fit.

2 more elements

A ball bearing assembly comprising:

retaining means for retaining a plurality of balls, said balls having a diameter;
a shaft;
a housing, wherein said retaining means comprising said plurality of balls is disposed between said shaft and said housing, wherein said housing is spaced from said shaft along a length, there being at least one first region and at least one second region along said length, wherein in said first region said shaft is spaced a first distance from said housing, said first distance being greater than said diameter of said balls, and wherein in said second regions said shaft is spaced a second distance from said shaft, said second distance being less than said diameter of said balls, wherein said ball bearing assembly has a clearance stroke range when said plurality of balls are between said shaft and said housing in said first region, and said ball bearing assembly has an interference stroke range when at least some of said plurality of balls are between said shaft and said housing in said second region.

Dependencies are inferred from the claim text.

Ball bearing assembly

Life of this patent

Ball bearing assembly

Life of this patent

Abstract

Claims16