Nylon resin driven pulley

Patent metadata

Field	Value
Publication number	US-2017190353-A1
Application number	US-201715465817-A
Country	US
Kind code	A1
Filing date	Mar 22, 2017
Priority date	Sep 28, 2012
Publication date	Jul 6, 2017
Grant date	—

Abstract

A torque transmitting assembly is provided. The assembly includes a ball nut having an outer diameter and keyway slot therein, and a pulley positioned on the ball nut. The pulley includes a cylindrical outer surface, a bore extending through the pulley such that the pulley includes an inner surface, and at least one torque member formed on the inner surface and projecting radially inward to be received by the keyway slot.

First claim

Having thus described the invention, it is claimed:

1 . A torque transmitting assembly comprising:
a ball nut having an outer diameter and keyway slot therein; and a polymer pulley positioned on the ball nut, the pulley having a cylindrical outer surface, a bore extending through the pulley such that the pulley includes an inner surface, a cut-out formed in the inner surface, and at least one torque member formed on the inner surface and projecting radially inward to be received by the keyway slot, wherein the cut-out and the at least one torque member are diametrically opposed on the inner surface; and wherein the ball nut includes a ball guide and a groove at least partially receiving the ball guide, the cut-out providing clearance to and interference and retention of the ball guide when the pulley is coupled to the ball nut.

2 . The torque transmitting assembly of claim 1 , wherein the pulley is made from glass filled nylon.

3 . The torque transmitting assembly of claim 1 , wherein the bore comprises a first section having a first radius and a second section having a second radius, the first radius being greater than the second radius.

4 . The torque transmitting assembly of claim 3 , wherein the pulley is pressed onto the ball nut.

5 . The torque transmitting assembly of claim 4 , wherein the pulley inner surface is configured to deform in the region of the second section when pressed onto the ball nut to present a substantially flat portion along the outer surface.

6 . The torque transmitting assembly of claim 1 , further comprising a plurality of teeth circumferentially spaced along the pulley outer surface.

7 . A method of fabricating a ball nut assembly, the method comprising:
providing a ball nut having a keyway slot; and forming a polymer pulley having an inner surface defining a bore, a cut-out formed in the inner surface, and a torque member extending radially inward from the inner surface, wherein the keyway slot is configured to receive the torque member therein.

8 . The method of claim 7 , wherein forming the polymer pulley further comprises fabricating the pulley from nylon resin.

9 . The method of claim 7 , further comprising forming a groove on an end of the ball nut and inserting a retainer into the groove.

10 . The method of claim 7 , further comprising inserting the polymer pulley onto the ball nut such that torque member is at least partially within the keyway slot.

11 . The method of claim 10 , further comprising deforming a portion of the polymer pulley proximate the cut-out to define a generally flat portion of the pulley.

12 . The method of claim 7 , further comprising forming a flange and coupling the flange to the polymer pulley.

13 . A method of fabricating a torque transmitting assembly, the method comprising:
providing a ball nut having an outer diameter; and forming a polymer pulley having a cylindrical outer surface, an inner surface defining a bore extending through the pulley, a cut-out formed in the inner surface, and at least one torque member extending from the inner surface into the bore.

14 . The method of claim 13 , where the step of providing a ball nut comprises providing a ball nut having a keyway slot.

15 . The method of claim 13 , wherein forming the polymer pulley further comprises fabricating the pulley from nylon resin.

16 . The method of claim 13 , further comprising forming a groove on an end of the ball nut and inserting a retainer into the groove.

17 . The method of claim 14 , further comprising inserting the polymer pulley onto the ball nut such that the at least one torque member is at least partially within the keyway slot.

18 . The method of claim 17 , further comprising deforming a portion of the polymer pulley proximate the cut-out to define a generally flat portion of the pulley.

19 . A steering system comprising:
a motor; a shaft rotatably coupled to the motor; a first pulley coupled to the shaft; a ball screw; and a torque transmitting assembly comprising:
a ball nut having an outer diameter;
and a second polymer pulley positioned on the ball nut, the second polymer pulley having a cylindrical outer surface, an inner surface defining a bore extending through the pulley, a cut-out formed in the inner surface, and at least one torque member extending from the inner surface into the bore, the bore comprises a first radius, and the cut-out comprises a second radius that is smaller than the first radius, the ball nut includes a ball guide and a groove at least partially receiving the ball guide, the cut-out provides clearance to and interference and retention of the ball guide when the second polymer pulley is coupled to the ball nut, at least a portion of the ball guide extends out of the groove beyond an outermost surface of the ball nut, and the ball nut includes a keyway slot to receive the at least one torque member.

20 . The system of claim 19 , wherein the cut-out and the at least one torque member are diametrically opposed on the inner surface.

Assignees

• Steering Solutions Ip Holding

Inventors

• Shavrnoch James J
• Strieter Troy P
• Dodak Tony M
• Otto Jeffrey M
• Vorwerck Conrad G

Classifications

• F16H25/2204

  with balls · CPC title

• F16H2025/2096

  using endless flexible members · CPC title

• B62D5/0448 Primary

  Ball nuts · CPC title

• B62D5/0424

  the axes of motor and final driven element of steering gear, e.g. rack, being parallel · CPC title

• F16H55/48

  manufactured exclusively or in part of non-metallic material, e.g. plastics  (F16H55/38, F16H55/42, F16H55/46 take precedence) · CPC title