Anti-lash assembly for vehicle power steering

Patent metadata

Field	Value
Publication number	US-9470296-B1
Application number	US-201514689505-A
Country	US
Kind code	B1
Filing date	Apr 17, 2015
Priority date	Apr 17, 2015
Publication date	Oct 18, 2016
Grant date	Oct 18, 2016

Abstract

A vehicle power steering assembly comprises a steering member having a screw portion. The screw portion has an external screw thread convolution with a first lead spacing. A ball nut is operatively connected to the screw portion. A bushing is operatively connected to the screw portion. The bushing has a bushing screw thread convolution with a second lead spacing. The second lead spacing is different than the first lead spacing. The bushing biases the ball nut against the screw portion.

First claim

What is claimed is:

1. A vehicle power steering assembly comprising:
a steering member having a screw portion, wherein the screw portion has an external screw thread convolution with a first lead spacing;
a ball nut operatively connected to the screw portion; and
a bushing operatively connected to the screw portion, wherein the bushing has a bushing screw thread convolution with a second lead spacing different than the first lead spacing and the bushing biases the ball nut against the screw portion.

2. The vehicle power steering assembly of claim 1 further comprising:
a rack axis, wherein the external screw thread convolution and the bushing screw thread convolution are along the rack axis and the second lead spacing being different than the first lead spacing restrains the bushing laterally along the rack axis.

3. The vehicle power steering assembly of claim 1 wherein the bushing contacts the ball nut.

4. The vehicle power steering assembly of claim 1 further comprising:
a spring disposed between the ball nut and bushing.

5. The vehicle power steering assembly of claim 4 wherein the spring biases the bushing against the screw portion.

6. The vehicle power steering assembly of claim 4 wherein the spring produces first and second gaps between an end face of the ball nut and the bushing, and wherein the second gap is opposite and larger than the first gap.

7. The vehicle power steering assembly of claim 1 further comprising:
a first gap between an end face of the ball nut and the bushing; and
a second gap between the end face and the bushing, wherein the second gap is opposite and larger than the first gap.

8. The vehicle power steering assembly of claim 1 further comprising:
a notch on the ball nut; and
a member extending from the bushing, wherein the member enters the notch to rotationally restrain the bushing on the screw portion.

9. The vehicle power steering assembly of claim 1 further comprising:
a pin connecting the ball nut and the bushing, wherein the pin rotationally restrains the bushing on the screw portion.

10. A method of biasing a vehicle power steering assembly comprising the step of:
operatively connecting a ball nut to a screw portion of a steering member, wherein the screw portion has an external screw thread convolution with a first lead spacing;
operatively connecting a bushing to the screw portion, wherein the bushing has a bushing screw thread convolution with a second lead spacing different than the first lead spacing; and
tightening the bushing against the ball nut to bias the ball nut against the screw portion.

11. The method of claim 10 comprising the further step of:
compressing a spring between the ball nut and the bushing.

12. The method of claim 11 wherein the spring produces first and second gaps between an end face of the ball nut and the bushing, wherein the second gap is opposite and larger than the first gap.

Assignees

• Trw Automotive Us Llc

Inventors

• Beyerlein Jeffrey

Classifications

• F16H25/2209 Primary

  with arrangements for taking up backlash · CPC title

• B62D5/0421

  Electric motor acting on or near steering gear · CPC title

• B62D5/20

  specially adapted for particular type of steering gear or particular application (steering gears per se B62D3/00; steering linkages not characterised by being power-assisted or power-driven B62D7/00) · CPC title

• B62D5/0448

  Ball nuts · CPC title

• F16H2025/2096

  using endless flexible members · CPC title