Steering assembly and method

• US 5,544,522 A
• Filed: 10/28/1994
• Issued: 08/13/1996
• Est. Priority Date: 10/28/1994
• Status: Expired due to Term

• Current Assignee: TRW Inc. (Northrop Grumman Corporation)
• Original Assignee: TRW Inc. (Northrop Grumman Corporation)
• Inventors: Little, Scott C.
• Primary Examiner(s): Culbreth, Eric D.
• Assistant Examiner(s): ZEENDER, FLORIAN M
• Application Number:
  US08/330,986
• Time in Patent Office: 655 Days
• Field of Search: 180/148, 180/79, 180/DIG. 17, 180/DIG. 18, 73/118.1, 33/600, 33/606, 33/612
• US Class Current: 73/117.02
• CPC Class Codes: B62D 3/123 characterised by pressure yokes
• CPC Class Codes: F16H 2057/0227 Assembly method measuring first tolerances or position and selecting mating parts accordingly, e.g. special sized shims for transmission bearings
• CPC Class Codes: F16H 55/283 using pressure yokes
• CPC Class Codes: F16H 57/12 Arrangements for adjusting or for taking-up backlash not provided for elsewhere

Abstract

A steering assembly (10) for use in turning steerable vehicle wheels includes a rack (12) and a pinion (14). A yoke (28) is continuously pressed against the rack (12) by a yoke spring (32). The yoke (28) has a stem (62) which extends through an opening (64) in a housing (16). During construction of the steering assembly (10), a desired range of transverse movement between the rack (112) and the pinion (14) is obtained by applying force (114) to the rack to position the rack at a first end of the range of transverse movement. The direction of the force applied to the rack (12) is then reversed and the rack and yoke (28) are moved together away from the reference position until the yoke stem (62) has moved through the desired range of transverse movement. A yoke plug (20) is then fixed against movement relative to a main housing section (18). After the rack and pinion steering assembly (10) has been constructed, it may be desired to check the range of transverse movement between the rack (12) and pinion (14). The distance between opposite ends of the range of transverse movement is determined by determining the distance through which the stem (62) on the yoke (28) moves relative to the housing (16).

Claims

1. A method of obtaining a desired range of movement between a rack and a pinion of a steering assembly in a direction transverse to a longitudinal axis of the rack, said method comprising the steps of:

applying force to the rack to position the rack at a first end of the desired range of movement;

pressing a yoke against the rack when the rack is at the first end of the desired range of movement to position the yoke at a first reference position;

moving the yoke away from the first reference position;

measuring the distance through which the yoke moves away from the first reference position;

interrupting movement of the yoke away from the first reference position when the measured distance is equal to the desired range of transverse movement between the rack and pinion and the yoke has moved to a second reference position for the yoke; and

blocking further movement of the yoke away from the first reference position when the yoke is at the second reference position.

2. A method as set forth in claim 1 wherein said step of moving the yoke away from the first reference position includes applying force to the rack to move the rack away from the first end of the desired range of movement.

3. A method as set forth in claim 2 wherein said step of moving the yoke away from the first reference position includes pressing the yoke against the rack during movement of the yoke away from the first reference position.

4. A method as set forth in claim 1 further including detecting the position of a surface connected with the yoke relative to a housing which at least partially encloses the rack and pinon when the yoke is at the first reference position, and detecting when the position of the surface connected with the yoke has moved relative to the housing through a distance equal to the desired range of transverse movement between the rack and pinion during movement of the yoke away from the first reference position.

5. A method as set forth in claim 1 wherein said step of blocking further movement of the yoke away from the first reference position when the yoke is at the second reference position includes securing a yoke plug against movement relative to a housing which at least partially encloses the rack and pinion.

6. A method as set forth in claim 1 further including the step of pressing a surface area on the yoke against a surface area on a yoke plug and moving the yoke plug in a direction away from the first reference position during performance of said step of moving the yoke away from the first reference position.

7. A method as set forth in claim 1 further including the steps of rotating a yoke plug in a first direction relative to a housing which at least partially encloses the rack and pinion with a thread convolution on the yoke plug in engagement with a thread convolution on the housing to move the yoke plug toward the first reference position, rotating the yoke plug in a second direction opposite to the first direction during movement of the yoke away from the first reference position, pressing a surface on the yoke against a surface on the yoke plug during rotation of the yoke plug in the second direction and movement of the yoke away from the first reference position, and interrupting rotation of the yoke plug in the second direction upon movement of the yoke away from the first reference position through a distance which is equal to the desired range of transverse movement between the rack and pinion.

8. A method as set forth in claim 1 wherein said step of measuring the distance through which the yoke moves away from the first reference position includes engaging a housing which at least partially encloses the rack and pinion with a first portion of a sensor assembly, engaging a surface connected with the yoke with a second portion of the sensor assembly when the yoke is in the first reference position, moving the second portion of the sensor assembly relative to the first portion of the sensor assembly during movement of the yoke away from the first reference position, providing an output from the sensor assembly upon movement of the second portion of the sensor assembly relative to the first portion of the sensor assembly, and interrupting movement of the yoke away from the first reference position upon movement of the second portion of the sensor assembly relative to the first portion of the sensor assembly through a distance which is equal to the desired range of transverse movement between the rack and pinion.

9. A method as set forth in claim 8 wherein said step of moving the second portion of the sensor assembly relative to the first portion of the sensor assembly is performed with the surface connected with the yoke in engagement with the second portion of the sensor assembly.

10. A method as set forth in claim 1 further including positioning a yoke plug relative to a housing which at least partially encloses the rack and pinion with a stem portion of the yoke extending through an opening in the yoke plug, said step of moving the yoke away from the first reference position includes moving the yoke and the yoke plug together in a direction away from the first reference position with the stem portion of the yoke extending through the opening in the yoke plug.

11. A method of determining the range of movement between a rack and a pinion of a steering assembly in a direction transverse to a longitudinal axis of the rack, said method comprising the steps of:

applying force to the rack to position the rack at a first end of the range of movement;

pressing a yoke against the rack when the rack is at the first end of the range of movement to position the yoke at a first reference position;

moving the rack away from the first end of the range of movement to a second end of the range of movement;

pressing the yoke against the rack when the rack is at the second end of the range of movement to position the yoke in a second reference position; and

measuring the extent of movement of the yoke between the first and second reference positions to determine the distance which the rack moves between the first and second ends of the range of movement.

12. A method as set forth in claim 11 wherein said step of applying force to the rack to position the rack at a first end of the range of movement includes applying the force to the rack in a first direction, said step of moving the rack away from the first end of the range of movement to a second end of the range of movement includes applying force in a second direction to the rack.

13. A method as set forth in claim 11 further including the step of pressing the yoke against the rack during movement of the rack away from the first end of the range of movement to the second end of the range of movement.

14. A method as set forth in claim 11 further including the step of interrupting movement of the rack away from the first end of the range of movement by pressing the yoke against a surface connected with a housing which at least partially encloses the rack and pinion when the rack reaches the second end of the range of movement.

15. A method as set forth in claim 11 further including engaging a housing which at least partially encloses the rack and pinion with a first portion of a sensor assembly and engaging a surface connected with the yoke with a second portion of the sensor assembly when the yoke is at the first reference position, and moving the second portion of the sensor assembly relative to the first portion of the sensor assembly during movement of the yoke away from the first reference position to the second reference position, said step of measuring the extent of movement of the yoke between the first and second reference positions including determining the distance which the second portion of the sensor assembly moves relative to the first portion of the sensor assembly during movement of the yoke from the first reference position to the second reference position.

16. A method as set forth in claim 11 wherein said step of moving the rack away from the first end of the range of movement to a second end of the range of movement includes moving a stem portion of the yoke relative to a yoke plug from a first position in which the stem portion of the yoke projects a first distance outward from an outer side surface of the yoke plug to a second position in which the stem portion of the yoke projects a second distance outward from an outer side surface of the yoke plug, said step of measuring the extent of movement of the yoke between the first and second reference positions of the yoke includes determining the difference between the first distance which the stem portion of the yoke projects outward from the yoke plug and the second distance which the stem portion of the yoke projects outward from the plug.

17. A method comprising the steps of:

engaging a rack of a rack and pinion steering assembly with a yoke;

moving the rack from a first end of a range of transverse movement of the rack relative to the pinion to a second end of the range of transverse movement of the rack relative to the pinion with the yoke in engagement with the rack; and

measuring the distance through which the yoke moves during movement of the rack from the first end of the range of transverse movement of the rack relative to the pinion to the second end of the range of transverse movement of the rack relative to the pinion.

18. A method as set forth in claim 17 wherein the yoke has a stem portion which extends through an opening in a housing which at least partially encloses the rack and pinion, said step of measuring the distance through which the yoke moves during movement of the rack from the first end of the range of transverse movement of the rack relative to the pinion to the second end of the range of transverse movement of the rack relative to the pinion includes measuring the distance through which the stem portion of the yoke moves relative to the housing.

19. A method as set forth in claim 18 wherein said step of measuring the distance through which the stem portion of the yoke moves relative to the housing includes engaging the housing with a first portion of a sensor assembly, engaging the stem portion of the yoke with a second portion of the sensor assembly, and moving the second portion of the sensor assembly relative to the first portion of the sensor assembly during movement of the rack from the first end of the range of transverse movement of the rack relative to the pinion and the second end of the range of transverse movement of the rack relative to the pinion.