Adjusting unit for an automatic slack adjuster

Patent metadata

Field	Value
Publication number	US-10107345-B2
Application number	US-201615145146-A
Country	US
Kind code	B2
Filing date	May 3, 2016
Priority date	May 11, 2015
Publication date	Oct 23, 2018
Grant date	Oct 23, 2018

Abstract

An adjusting unit for an automatic slack adjuster of a vehicle drum brake includes a housing (19), a worm shaft (2) mounted in the housing (19) so as to be movable between two end positions along an axial travel (A), a control pinion (9) arranged on the worm shaft, a worm (7) arranged on the worm shaft, and a freewheel (13) for power transmission between the control pinion (9) and the worm (7) in a first direction of rotation and for slip between the control pinion (9) and the worm (7) in an opposite, second direction of rotation. The worm shaft (2) has a first stop surface (3) and a second stop surface (5), which can each be brought into contact with a corresponding first stop (25) and second stop (21) at the end positions of the housing (19). An automatic slack adjuster includes such an adjusting unit.

First claim

What is claimed is:

1. An adjusting unit ( 1 ) for an automatic slack adjuster ( 100 ) of a brake ( 200 ), in particular of a commercial vehicle drum brake, the adjusting unit comprising:
a housing ( 19 ),
a worm shaft ( 2 ), which is mounted in the housing ( 19 ) so as to be movable between two end positions along an axial travel (A),
a control pinion ( 9 ) arranged on the worm shaft,
only one axial spring ( 11 ),
a worm ( 7 ) arranged on the worm shaft, and
a freewheel ( 13 ), which is designed for power transmission between the control pinion ( 9 ) and the worm ( 7 ) in a first direction of rotation and for slip between the control pinion ( 9 ) and the worm ( 7 ) in an opposite, second direction of rotation,
wherein the worm shaft ( 2 ) has a first stop surface ( 3 ) and a second stop surface ( 5 ), the first stop surface ( 3 ) being spaced apart from a corresponding first stop ( 25 ) at one of the two end positions of the housing ( 19 ), the first stop surface and the second stop surface each configured to be brought into contact with the corresponding first stop ( 25 ) or a corresponding second stop ( 21 ) of the housing ( 19 ) when the worm shaft ( 2 ) is moved to one of the two end positions,
wherein the worm shaft ( 2 ) has a sliding bearing section ( 6 ) inserted into a guide recess ( 23 ) of the housing ( 19 ), the sliding bearing section ( 6 ) extending from the second stop surface ( 5 ) to the corresponding second stop ( 21 ) and being in direct contact with the guide recess ( 23 ),
wherein the axial spring ( 11 ) is operatively connected to the housing ( 19 ) and the worm shaft ( 2 ) and is designed to preload the worm shaft ( 2 ) in the direction of the corresponding second stop ( 21 ).

2. The adjusting unit ( 1 ) as claimed in claim 1 , wherein the worm ( 7 ) is fixedly connected to the worm shaft ( 2 ), and the control pinion ( 9 ) is coupled to the worm shaft ( 2 ) via the freewheel ( 13 ).

3. The adjusting unit ( 1 ) as claimed in claim 1 , wherein the control pinion ( 9 ) is arranged for conjoint rotation on the worm shaft ( 2 ), and the worm ( 7 ) is coupled to the worm shaft ( 2 ).

4. The adjusting unit ( 1 ) as claimed in claim 1 , wherein the axial spring ( 11 ) is designed as: a helical spring, diaphragm spring, wave spring or a combination of the above.

5. The adjusting unit ( 1 ) as claimed in claim 1 , wherein the control pinion ( 9 ) is mounted on the worm shaft ( 2 ) and has a recess ( 17 ) for accommodating the axial spring ( 11 ).

6. The adjusting unit ( 1 ) as claimed in claim 5 , wherein the recess ( 17 ) of the control pinion ( 9 ) is located on a side facing the first stop surface ( 3 ).

7. The adjusting unit ( 1 ) as claimed in claim 1 , wherein the first stop surface ( 3 ) is formed as a shaft end.

8. The adjusting unit ( 1 ) as claimed in claim 1 , wherein the second stop surface ( 5 ) is formed as a shaft shoulder.

9. The adjusting unit ( 1 ) as claimed in claim 1 , wherein the sliding bearing section ( 6 ) is supported loosely in the housing ( 19 ) adjacent to the second stop surface ( 5 ).

10. The adjusting unit ( 1 ) as claimed in claim 9 , wherein the sliding bearing section ( 6 ) is formed from a hardened metallic material.

11. The adjusting unit ( 1 ) as claimed in claim 1 , wherein the worm ( 7 ) and the control pinion ( 9 ) are arranged between the first and second stop surfaces ( 3 , 5 ) in the axial direction.

12. The adjusting unit ( 1 ) as claimed in claim 1 , wherein the freewheel ( 13 ) is designed as: a wrap spring, roller freewheel, bevel toothing with a preload, locking pawl or a combination of the above.

13. An automatic slack adjuster ( 100 ) for a vehicle drum brake comprising an adjusting unit ( 1 ) as claimed in claim 1 .

14. A vehicle ( 300 ) having a plurality of wheels at least one of which being associated with a drum brake ( 200 ) having an automatic slack adjuster ( 100 ) comprising an adjusting unit ( 1 ) as claimed in claim 1 .

15. An adjusting unit ( 1 ) for an automatic slack adjuster ( 100 ) of a brake ( 200 ), in particular of a commercial vehicle drum brake, the adjusting unit comprising:
a housing ( 19 ),
a worm shaft ( 2 ), which is mounted in the housing ( 19 ) so as to be movable between two end positions along an axial travel (A),
a control pinion ( 9 ) arranged on the worm shaft,
a worm ( 7 ) arranged on the worm shaft, and
a freewheel ( 13 ), which is designed for power transmission between the control pinion ( 9 ) and the worm ( 7 ) in a first direction of rotation and for slip between the control pinion ( 9 ) and the worm ( 7 ) in an opposite, second direction of rotation,
wherein the worm shaft ( 2 ) has a first stop surface ( 3 ) and a second stop surface ( 5 ), the first stop surface ( 3 ) being spaced apart from a corresponding first stop ( 25 ) at one of the two end positions of the housing ( 19 ), the first stop surface and the second stop surface each configured to be brought into contact with the corresponding first stop ( 25 ) or a corresponding second stop ( 21 ) of the housing ( 19 ) when the worm shaft ( 2 ) is moved to one of the two end positions,
wherein the worm shaft has a sliding bearing section ( 6 ) inserted into a guide recess ( 23 ) of the housing ( 19 ), the sliding bearing section ( 6 ) extending from the second stop surface ( 5 ) to the corresponding second stop ( 21 ) and being in direct contact with the guide recess ( 23 ),
wherein the guide recess ( 23 ) is longer than the sliding bearing section ( 6 ).

16. An adjusting unit ( 1 ) for an automatic slack adjuster ( 100 ) of a brake ( 200 ), in particular of a commercial vehicle drum brake, the adjusting unit comprising:
a housing ( 19 ),
a worm shaft ( 2 ), which is mounted in the housing ( 19 ) so as to be movable between two end positions along an axial travel (A),
a control pinion ( 9 ) arranged on the worm shaft,
a worm ( 7 ) arranged on the worm shaft, and
a freewheel ( 13 ), which is designed for power transmission between the control pinion ( 9 ) and the worm ( 7 ) in a first direction of rotation and for slip between the control pinion ( 9 ) and the worm ( 7 ) in an opposite, second direction of rotation,
wherein the worm shaft ( 2 ) has a first stop surface ( 3 ) and a second stop surface ( 5 ), the first stop surface ( 3 ) being spaced apart from a corresponding first stop ( 25 ) at one of the two end positions of the housing ( 19 ), the first stop surface and the second stop surface each configured to be brought into contact with the corresponding first stop ( 25 ) or a corresponding second stop ( 21 ) of the housing ( 19 ) when the worm shaft ( 2 ) is moved to one of the two end positions,
wherein the worm shaft has a sliding bearing section ( 6 ) inserted into a guide recess ( 23 ) of the housing ( 19 ), the sliding bearing section ( 6 ) extending from the second stop surface ( 5 ) to the corresponding second stop ( 21 ) and being in direct contact with the guide recess ( 23 ),
wherein the entire sliding bearing section ( 6 ) overlaps with the guide recess ( 23 ) when the second stop surface ( 5 ) is in contact with the corresponding second stop ( 21 ).

17. The adjusting unit ( 1 ) as claimed in claim 16 , further comprising only one axial spring ( 11 ), the axial spring ( 11 ) being operatively connected to the housing ( 19 ) and the worm shaft ( 2 ) and being designed to preload the worm shaft ( 2 ) in the direction of the corresponding second stop ( 21 ).

Assignees

• Wabco Europe Bvba

Inventors

• Keller Marcus
• Stafflinger Markus

Classifications

• F16D65/60 Primary

  for angular adjustment of two concentric parts of the brake control systems · CPC title

• F16D65/48 Primary

  with eccentric or helical body · CPC title

• F16D51/00

  Brakes with outwardly-movable braking members co-operating with the inner surface of a drum or the like (similar clutches F16D13/14) · CPC title

• F16D65/68 Primary

  with eccentric or helical body · CPC title