Grinding robot and method for grinding electrically conductive workpieces

Patent metadata

Field	Value
Publication number	US-11772233-B2
Application number	US-201916519992-A
Country	US
Kind code	B2
Filing date	Jul 23, 2019
Priority date	Jan 23, 2017
Publication date	Oct 3, 2023
Grant date	Oct 3, 2023

Abstract

A grinding robot for grinding an electrically conducting workpiece. The grinding robot includes a grinding wheel, an actuation device for actuating grinding wheel, and a control system. The grinding wheel including an undulated tool receptacle which defines an axis of rotation about which the grinding wheel can rotate during grinding, and a head which is rotationally symmetrical with respect to the axis of rotation, and which contains abrasive material and has a grinding surface which is in contact with workpiece during grinding. The grinding wheel also includes a measuring and transmission unit and at least one conductor strand pair with two conductor strands which are electrically insulated from one another. The conductor strands are embedded in the rotationally symmetrical head and extend from the grinding surface of the head into the interior of the head and are electrically connected with measuring and transmission unit.

First claim

What is claimed is:

1. A grinding robot for grinding an electrically conducting workpiece, comprising:
a grinding wheel, including:
an undulated tool receptacle which defines an axis of rotation about which the grinding wheel can rotate during grinding;
a head which is rotationally symmetrical with respect to the axis of rotation, and the head contains abrasive material and has a grinding surface that is configured for contacting the workpiece during grinding;
a measuring and transmission unit; and
at least one conductor strand pair including two conductor strands which are electrically insulated from one another, the conductor strands are embedded in the head and extend from the grinding surface of the head into an interior of the head and are electrically connected with the measuring and transmission unit,

an actuation device for actuating the grinding wheel; and
a control system which is connected with the actuation device and which controls the grinding wheel,
wherein the conductor strands are arranged in such a way that during grinding, due to the contact with the workpiece, a closed electrical circuit is created for measuring a resistance value, wherein the electric circuit progresses from the measuring and transmission unit via one conductor strand, the workpiece, and the other conductor strand back to the measuring and transmission unit, and the conductor strands are designed in such a way that a measured resistance is dominated by a resistance of conductor strands, so that the measured resistance is a reciprocal proportional measurement for a degree of wear of the head, and wherein the measuring and transmission unit is configured for measuring and transmitting the measured resistance to the control system and wherein the control system is configured for considering the measured resistance in determining whether a predefined surface contour of the workpiece has been achieved.

2. The grinding robot according to claim 1 , wherein the conductor strands are insulated in that they are separately arranged from one another.

3. The grinding robot according to claim 1 , wherein an electrical insulating material is disposed between the conductor strands.

4. The grinding robot according to claim 3 , wherein the conductor strands progress parallel to one another.

5. The grinding robot according to claim 3 , wherein the conductor strands progress coaxially, parallel to one another, and wherein one conductor strand is tubular and includes the other conductor strand.

6. The grinding robot according to claim 1 , wherein the conductor strands consist of graphite.

7. The grinding robot according to claim 1 , wherein the conductor strands consist of carbon fiber.

8. The grinding robot according to claim 1 , wherein the measuring and transmission unit includes a battery.

9. The grinding robot according to claim 1 , wherein the measuring and transmission unit comprises a super capacitor.

10. The grinding robot according to claim 1 , wherein the measuring and transmission unit is configured to transmit the measured resistance to the control system by Bluetooth®.

11. The grinding robot according to claim 1 , wherein the grinding wheel includes a disc for measuring bending of the tool receptacle, and the wherein measuring and transmission unit is configured to transmit a measured value of bending to the control system.

12. The grinding robot according to claim 11 , wherein the disc which is mounted on the tool receptacle.

13. The grinding robot according to claim 12 , wherein the measuring and transmission unit includes at least one sensor which is configured for measuring a distance between the disc and the measuring and transmission unit.

14. A method for grinding an electrically conducting workpiece, comprising:
providing a grinding robot for grinding the electrically conducting workpiece, the grinding robot including a grinding wheel, the grinding wheel including an undulated tool receptacle which defines an axis of rotation about which the grinding wheel can rotate during grinding, a head which is rotationally symmetrical with respect to the axis of rotation, and the head contains abrasive material and has a grinding surface that is configured for contacting the workpiece during grinding, a measuring and transmission unit, and at least one conductor strand pair including two conductor strands which are electrically insulated from one another, the conductor strands are embedded in the head and extend from the grinding surface of the head into an interior of the head and are electrically connected with the measuring and transmission unit, an actuation device for actuating the grinding wheel, and a control system which is connected with the actuation device and which controls the grinding wheel, wherein the conductor strands are arranged in such a way that during grinding, due to the contact with the workpiece, a closed electrical circuit is created for measuring a resistance value, wherein the electric circuit progresses from the measuring and transmission unit via one conductor strand, the workpiece, and the other conductor strand back to the measuring and transmission unit, and the conductor strands are designed in such a way that a measured resistance is dominated by a resistance of conductor strands, so that the measured resistance is a reciprocal proportional measurement for a degree of wear of the head, and wherein the measuring and transmission unit is configured for measuring and transmitting the measured resistance to the control system and wherein the control system is configured for considering the measured resistance in determining whether a predefined surface contour of the workpiece has been achieved;
moving the grinding wheel toward the workpiece until the grinding wheel is in contact with the workpiece; and
processing of the workpiece by the grinding wheel until a predefined surface contour on the workpiece is achieved, wherein the control system terminates the moving step and transitions to the processing step as soon as it has received the resistance value from the measuring and transmission unit, and wherein in the processing step the measuring and transmission unit constantly transmits the resistance value to the control system which considers the resistance value in determining whether the predefined surface contour has been achieved.

15. The method according to claim 14 , wherein the conductor strands are insulated in that they are separately arranged from one another.

16. The method according to claim 14 , wherein an electrical insulating material is disposed between the conductor strands.

17. The method according to claim 14 , wherein the conductor strands progress parallel to one another.

18. The method according to claim 17 , wherein the conductor strands progress coaxially, parallel to one another, and wherein one conductor strand is tubular and includes the other conductor strand.

19. The method according to claim 14 , wherein the grinding wheel includes a disc for measuring bending of the tool receptacle, and the wherein measuring and transmission unit is configured to transmit a measured value of bending to the control system.

20. The method according to claim 19 , further including a step of generating an error message by the control system and removing the grinding wheel from the workpiece if, in the moving step, the measuring and transmission unit transmits a measured value of bending that exceeds a predefined value of bending.

Assignees

• Voith Patent Gmbh

Inventors

• Rohrer Martin
• Weigl Florian
• Karner Stefan

Classifications

• B24B49/10 Primary

  involving electrical means (B24B49/02, B24B49/08 take precedence) · CPC title

• B24B1/002

  using electric current (B24B37/046 and B23H5/08 take precedence) · CPC title

• B24B41/002

  Grinding heads · CPC title

• B24B41/04

  Headstocks; Working-spindles; Features relating thereto · CPC title

• B24B49/183

  Wear compensation without the presence of dressing tools · CPC title