Method for determining the clamping force

Patent metadata

Field	Value
Publication number	US-2022011183-A1
Application number	US-202117484733-A
Country	US
Kind code	A1
Filing date	Sep 24, 2021
Priority date	Mar 26, 2019
Publication date	Jan 13, 2022
Grant date	—

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; model-based calculating the clamping force to be expected based on the actuation force and operating parameters of the machine tool in a control unit of the machine tool; clocked measuring the clamping force acting upon the object in the clamping device within a time span of a measurement interval; wirelessly transmitting the measured value to the control unit of the machine tool; comparing the measured value with a calculated clamping force; and adapting the measurement interval if the comparison reveals a deviation which reaches a threshold value.

2 . The method according to claim 1 , wherein the measurement interval is lengthened if the threshold value is not reached, and/or the measurement interface is shortened if 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 distance 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/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/equal to 2%, in particular a deviation of 1.5% and preferably a deviation of 0.5%.

7 . The method according to claim 1 , wherein a sensor is present for detecting the actuation force, whose measured data is transmitted in a wirebound manner to the control unit.

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.

Assignees

• Roehm Gmbh

Inventors

• Stangl Martin

Classifications

• G08C17/02

  using a radio link · CPC title

• H04Q2209/40

  using a wireless architecture · CPC title

• G01L5/0061 Primary

  Force sensors associated with industrial machines or actuators (for the specific machine or actuator involved see relevant class, e.g. F01, F04, F16, B66, E21) · 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

• B23B2260/128

  Sensors · CPC title