Integrated stud ball bearing with precision matched raceway contact angles for consistent stiffness of gimbal assembly

Patent metadata

Field	Value
Publication number	US-11668342-B2
Application number	US-202117389529-A
Country	US
Kind code	B2
Filing date	Jul 30, 2021
Priority date	Feb 1, 2019
Publication date	Jun 6, 2023
Grant date	Jun 6, 2023

Abstract

A ball bearing and housing assembly includes a shaft having a stepped bore extending therethrough. The stepped bore is defined by a first bore segment having an inboard cylindrical interior surface that has a first bore diameter. The first bore segment extends from a shaft end and terminates at a shoulder. The shoulder is axially located between a first radial centerline of a plurality of balls and an inner axial end. The stepped bore is further defined by a second bore segment having an outboard cylindrical interior surface that has second bore diameter. The second bore segment extends axially from the inner axial end towards the shaft end and terminates at the shoulder. The second bore diameter is greater than the first bore diameter. A fastener is fitted through the first bore segment and threaded into a housing.

First claim

What is claimed is:

1. A ball bearing and housing assembly comprising:
a one piece inner ring extending from a first inner axial end to a second inner axial end, the inner ring having a first radially outwardly facing circumferential hub extending axially inward from the first inner axial end and a second radially outwardly facing circumferential hub extending axially inward from the second inner axial end, a first arcuate inner race extending from the first radially outwardly facing circumferential hub, the inner ring having a second arcuate inner race extending from the second radially outwardly facing circumferential hub, a radially outwardly facing cylindrical surface extending axially between the first arcuate inner race and the second arcuate inner race, the inner ring being integrally formed on a shaft and fixed relative thereto about a longitudinal axis, the shaft extending axially away from the first inner axial end and terminating at a shaft end and the shaft having a shaft outside diameter;
a one piece outer ring positioned coaxially around the inner ring and extending from a first outer axial end to a second outer axial end, a first radially inwardly facing circumferential rim extending axially inward from the first outer axial end and a second radially inwardly facing circumferential rim extending axially inward from the second outer axial end, the outer ring having a first arcuate outer race extending from an axially innermost portion of the first radially inwardly facing circumferential rim and terminating at a first radially outermost portion of the first arcuate outer race, the outer ring having a second arcuate outer race extending from an axially innermost portion of the second radially inwardly facing circumferential rim and terminating at a second radially outermost portion of the second arcuate outer race, a radially inwardly facing cylindrical surface extending axially between the first radially outermost portion of the first arcuate outer race and the second radially outermost portion of the second arcuate outer race;
a first plurality of balls disposed between and in rolling engagement with the first arcuate outer race and the first arcuate inner race;
a second plurality of balls disposed between and in rolling engagement with the second arcuate outer race and the second arcuate inner race;
the outer ring being rotatable relative to the inner ring about the longitudinal axis;
the first plurality of balls having a first contact angle between a first radial centerline perpendicular to the longitudinal axis and a first reference line that connects opposing first contact points of the first plurality of balls with the first arcuate outer race and the first arcuate inner race;
the second plurality of balls having a second contact angle between a second radial centerline perpendicular to the longitudinal axis and a second reference line that connects opposing second contact points of the second plurality of balls with the second arcuate outer race and the second arcuate inner race;
the first reference line and the second reference line intersecting at an intersection position in the inner ring;
the shaft having a stepped bore extending therethrough, the stepped bore being defined by:
(i) a first bore segment having an inboard cylindrical interior surface that has a first bore diameter, the first bore segment extending from the shaft end and terminating at a shoulder that faces axially toward the second inner axial end, the shoulder being axially located between the first radial centerline of the first plurality of balls and the second inner axial end; and
(ii) a second bore segment having an outboard cylindrical interior surface that has a second bore diameter, the second bore segment extending axially from the second inner axial end towards the shaft end and terminating at the shoulder, the second bore diameter being greater than the first bore diameter;
a housing having an exterior surface axially facing the first inner axial end, a recess extending axially into the exterior surface, having a recess inside diameter and being parallel to the first inner axial end, a female threaded bore extending axially into the recess, the recess inside diameter being about equal to the shaft outside diameter, the shaft end being seated in the recess such that the shaft end abuts the recess; and
a fastener extending from an inboard fastener end to an outboard fastener end, the fastener having a male threaded surface extending along the fastener from the inboard fastener end towards the outboard fastener end, and a fastener head formed on the fastener and extending axially from the outboard fastener end towards the inboard fastener end and terminating at a fastener abutment surface that faces axially toward the inboard fastener end,
wherein the fastener is fitted through the first bore segment and threaded into the housing so that a portion of the male threaded surface threadedly engages a portion of the female threaded bore so that the shaft end abuts the recess and the fastener abutment surface abuts the shoulder and compresses the shaft and the first radially outwardly facing circumferential hub between the fastener head and the recess.

2. The ball bearing and housing assembly of claim 1 , wherein the intersection position in the inner ring is located radially inward from the first arcuate inner race and the second arcuate inner race.

3. The ball bearing and housing assembly of claim 1 , wherein the shoulder is axially located equidistant between the first inner axial end and the second inner axial end.

4. The ball bearing and housing assembly of claim 1 , further comprising an annular gap located between the housing and the first inner axial end for receiving a device.

5. The ball bearing and housing assembly of claim 1 , wherein the first inner axial end is coplanar with a first axial end of the outer ring.

6. The ball bearing and housing assembly of claim 1 , wherein at least one of the first contact angle and the second contact angle is about 25 degrees to about 35 degrees.

7. The ball bearing and housing assembly of claim 1 , wherein at least one of the first contact angle and the second contact angle is about 27 degrees to about 33 degrees.

8. The ball bearing and housing assembly of claim 7 , wherein the ball bearing and housing assembly has an axial stiffness of about 45,181 N/mm to about 68,441 N/mm.

9. The ball bearing and housing assembly of claim 7 , wherein the ball bearing and housing assembly has a radial stiffness of about 66,086 N/mm to about 88,005 N/mm.

10. The ball bearing and housing assembly of claim 7 , wherein the ball bearing and housing assembly has a moment stiffness of about 1,199 N-mm/rad to about 2,265 N-mm/rad.

11. The ball bearing and housing assembly of claim 1 , wherein at least one of the first contact angle and the second contact angle is about 29 degrees to about 31 degrees.

12. The ball bearing and housing assembly of claim 1 , wherein the first plurality of balls has a pitch diameter defined as two times a distance between the longitudinal axis and a ball central axis, a ratio of the pitch diameter to a thickness of the outer ring being about 600% to about 800%.

13. The ball bearing and housing assembly of claim 12 , wherein an outer ring outside diameter of the outer ring defined as two times a distance between the exterior surface of the outer ring and the longitudinal axis, and a ratio of the outer ring outside diameter to the pitch diameter is about 120% to about 140%.

14. The ball bearing and housing assembly of claim 1 , wherein the first arcuate inner race and the second arcuate inner r

Assignees

• Roller Company Of America Inc
• Roller Bearing Co America Inc

Inventors

• Habibvand Alex
• Cowles Jr John H
• Murphy Richard

Classifications

• F16C33/585

  of raceways, e.g. ribs to guide the rollers · CPC title

• F16C33/581

  integral with other parts, e.g. with housings or machine elements such as shafts or gear wheels · CPC title

• F16C33/49

  comb-shaped · CPC title

• F16C35/042

  Housings for rolling element bearings for rotary movement · CPC title

• F16C19/183 Primary

  with two rows at opposite angles · CPC title