Method for producing a gear worm which is located in particular on an armature shaft, and such a gear worm

Patent metadata

Field	Value
Publication number	US-11904381-B2
Application number	US-201917285219-A
Country	US
Kind code	B2
Filing date	Oct 4, 2019
Priority date	Oct 15, 2018
Publication date	Feb 20, 2024
Grant date	Feb 20, 2024

Abstract

The invention relates to a method for producing a gear worm (12) which is located in particular on an armature shaft (14) of an electromotive drive unit (10), wherein firstly a worm gear (20) having screw flanks (22) axially opposite one another on a longitudinal axis (18) is formed by means of a rolling tool, and subsequently a groove structure (24) which is concentric about the longitudinal axis (18) is formed on the screw flanks (22) by means of an additional process step. The invention also relates to a gear worm (12) produced according to the method according to the invention, and to a transmission drive unit (10) containing such a gear worm (12).

First claim

What is claimed is:

1. A method for producing a gear worm ( 12 ), the method comprising forming, with a roller burnishing tool, a worm toothing system ( 20 ) with worm flanks ( 22 ) which lie axially opposite one another on a longitudinal axis ( 18 ), and thereafter configuring on the worm flanks ( 22 ) a groove structure ( 24 ) which is concentric about the longitudinal axis ( 18 ), wherein the concentric groove structure ( 24 ) is produced by belt grinding.

2. The method as claimed in claim 1 , wherein the gear worm ( 12 ) is manufactured as a separate component with a central bore ( 26 ) along the longitudinal axis ( 18 ), and is subsequently pressed onto a shaft of a drive unit ( 10 ).

3. The method as claimed in claim 1 , wherein the roller burnishing tool forms an endless worm thread using a through-feed method with the belt grinding method which is linked to it directly, which endless worm thread is afterward cut to the desired length ( 13 ) of the gear worm ( 12 ).

4. The method as claimed in claim 1 , wherein, during roller burnishing, a surface roughness of the worm flanks ( 22 ) of Rz of up to 0.5 μm is produced, and the subsequently configured concentric groove structure ( 24 ) has a structured roughness of Rz of from 0.2 μm to 10 μm.

5. The method as claimed in claim 1 , wherein a surface roughness of the concentric groove structure ( 24 ) can be predefined by way of properties of a grinding belt ( 30 ) and precision adjustment of process parameters, in order to realize an optimum between a sufficient self-locking action and a satisfactory degree of efficiency of a worm gear mechanism ( 50 ).

6. The method as claimed in claim 1 , wherein a flexible grinding belt ( 30 ), including an abrasive paper, is used for the belt grinding, and the flexible grinding belt ( 30 ) is pressed against the worm flanks ( 22 ) by a profiled contact piece ( 32 ) at the same time against two worm flanks ( 22 ) which lie opposite one another in a thread channel.

7. The method as claimed in claim 1 , wherein, during roller burnishing, a surface roughness of the worm flanks ( 22 ) of Rz of up to 0.1 μm is produced, and the subsequently configured concentric groove structure ( 24 ) has a structured roughness of Rz of from 0.2 μm to 10 μm.

8. The method as claimed in claim 1 , wherein the gear worm ( 12 ) is arranged on an armature shaft ( 14 ) of an electric motor drive unit ( 10 ).

9. The method as claimed in claim 8 , wherein the gear worm ( 12 ) is manufactured as a separate component with a central bore ( 26 ) along the longitudinal axis ( 18 ), and is subsequently pressed onto the armature shaft ( 14 ).

10. The method as claimed in claim 1 , wherein a flexible grinding belt ( 30 ) is used for the belt grinding, and the flexible grinding belt ( 30 ) is pressed against the worm flanks ( 22 ) by a profiled contact piece ( 32 ).

11. The method as claimed in claim 10 , wherein, during the belt grinding, the gear worm ( 12 ) is set in rotation, and the flexible grinding belt ( 30 ) is pulled with the contact piece ( 32 ) in the process along the worm flanks ( 22 ) by way of the pitch of the worm toothing system ( 20 ).

12. The method as claimed in claim 10 , wherein the flexible grinding belt ( 30 ) is moved at a lower relative speed than a circumferential speed of the worm toothing system ( 20 ) as a result of the rotation of the gear worm ( 12 ), in order to configure the concentric groove structure ( 24 ) on the worm flanks ( 22 ).

Assignees

• Bosch Gmbh Robert

Inventors

• Bao Jie
• De Graaff Bernhard
• Cettier Daniel
• Qiao Guang
• Thoene Holger
• Hertwig Otmar
• Hertweck Volker

Classifications

• F16H57/0498

  Worm gearings · CPC title

• F16H57/0006

  Vibration-damping or noise reducing means specially adapted for gearings (devices for varying tension of belts, ropes or chains with damping means F16H7/0829; toothed members with construction providing vibration damping F16H55/14; reducing vibrations or noise of the gearbox casing F16H57/028; suppression of vibrations or noise of gear selectors F16H59/0208; control of hydrostatic fluid gearing preventing or reducing vibrations or noise F16H61/4183) · CPC title

• F16H55/24

  Special devices for taking up backlash · CPC title

• F16H55/22

  for transmissions with crossing shafts, especially worms, worm-gears · CPC title

• B60N2/02253

  characterised by the transmission between the electric motor and the seat or seat parts · CPC title