Method for determining the clamping force

Patent metadata

Field	Value
Publication number	US-12117357-B2
Application number	US-202117484733-A
Country	US
Kind code	B2
Filing date	Sep 24, 2021
Priority date	Mar 26, 2019
Publication date	Oct 15, 2024
Grant date	Oct 15, 2024

Abstract

A method for determining the clamping force of a force-actuated, rotationally drivable clamping device of a machine tool. An object is clamped with an actuation force F. Model-based calculation of the clamping force F calc to be expected is performed based on the actuation force F and the operating parameters of the machine tool in a control unit of the machine tool. Performing clocked measurement of the clamping force F real acting upon the object in the clamping device within the time span of a measurement interval I. Wireless transming the measured value F real to the control unit of the machine tool, and comparison of the measured value F real with the calculated clamping force F calc . The measurement interval is adapted if the comparison reveals a deviation which reaches a threshold value.

First claim

What is claimed is:

1. A method for determining a clamping force of a force actuated, rotationally drivable clamping device of a machine tool, the method comprising:
clamping an object with an actuation force, the actuation force being measured by a sensor;
model-based calculating the clamping force to be expected based on the actuation force and operating parameters of the machine tool in a control device of the machine tool;
clocked measuring the clamping force acting upon the object in the clamping device, by directly measuring the clamping force, within a time span of a measurement interval;
wirelessly transmitting the measured value of the clamping force to the control device of the machine tool;
comparing the measured value with the calculated clamping force;
adapting the measurement interval when the comparison reveals a deviation which reaches a threshold value; and
adjusting the operating parameters of the clamping device when the calculated clamping force deviates from the measure value.

2. The method according to claim 1 , wherein the measurement interval is lengthened when the threshold value is not reached, and/or the measurement interval is shortened when the threshold value is exceeded.

3. The method according to claim 1 , wherein a size of the change of the measurement interval is proportionate to a deviation of the measured value from the threshold value.

4. The method according to claim 1 , wherein the threshold value for a deviation where the measured value is less than the calculated clamping force is less than or equal to the threshold value for a deviation where the measured value is greater than calculated clamping force.

5. The method according to claim 1 , wherein the deformation sensitivity of the object to be clamped is taken into account in the definition of the threshold value for a deviation where measured value is greater than calculated clamping force.

6. The method according to claim 1 , wherein the threshold value lies at a deviation of less than or equal to 2%.

7. The method according to claim 1 , wherein the actuation force, measured by the sensor, is transmitted in a wirebound manner to the control device.

8. The method according to claim 1 , wherein the clamping device is formed by a chuck, and the sensor for measuring the clamping force is assigned to one of the clamping jaws.

9. The method according to claim 1 , wherein the threshold value lies at a deviation of 1.5%.

10. The method according to claim 1 , wherein the threshold value lies at a deviation of 0.5%.

Assignees

• Roehm Gmbh

Inventors

• Stangl Martin

Classifications

• H04Q2209/40

  using a wireless architecture · CPC title

• H04Q9/00

  Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom · CPC title

• G08C17/02

  using a radio link · CPC title

• B23B2260/128

  Sensors · CPC title

• B23B2231/26

  Detection of clamping · CPC title