METHOD FOR MEASURING TORQUE OF A DRIVE UNIT

Abstract

The invention relates to a method for measuring the torque of a drive unit (10), particularly a vehicle drive unit (10), said drive unit (10) comprising at least one bearing (20) for connecting to a fixed support point (21), and at least one sensor (22) being provided which measures a change in force and/or position, particularly a relative rotation of the drive unit (10), as a sensor value, wherein a torque at the drive unit (10) is determined as a measurement value on the basis of said sensor value.

Claims

1. A method for measuring the torque of a drive unit (10), wherein the drive unit (10) comprises at least one bearing for connecting to a fixed support point, the method comprising providing at least one sensor that measures a change in a force and/or a position as a sensor value, and determining a torque that is applied to the drive unit (10) as a measurement value from the sensor value.

2. The method as claimed in claim 1, characterized in that a control unit (30) is provided, wherein the control unit (30) has a signal connection to the at least one sensor (22) and the measurement value is determined from the sensor value.

3. The method as claimed in claim 1, characterized in that the measurement value is determined from the sensor value and at least one bearing characteristic value.

4. The method as claimed in claim 1, characterized in that the drive unit (10) comprises a second bearing (20) for connecting to at least one fixed support point (21).

5. The method as claimed in claim 1, characterized in that the at least one sensor is disposed on the drive unit (10) and/or on the bearing (23) and at least one sensor is disposed on the fixed support point.

6. The method as claimed in claim 1, characterized in that the at least one sensor is a distance sensor.

7. The method as claimed in claim 1, characterized in that the at least one sensor is an inertial sensor, whereby a relative angular position of the drive unit (10) can be determined.

8. The method as claimed in claim 1, characterized in that the sensor is a force transducer, whereby a change in the force on the bearing can be measured.

9. The method as claimed in claim 1, characterized in that at least one sensor is disposed on a drive machine (11) of the drive unit (10).

10. A measuring system for measuring the torque of a drive unit (10), the measuring system comprising at least one sensor configured to measure a change in a force and/or a position, and at least one control unit (30), wherein the control unit (30) has a signal connection to the at least one sensor and is configured to carry out a torque measurement according to the method as claimed in claim 1.

11. A measuring system for measuring the torque of a vehicle drive unit (10), the measuring system comprising at least one sensor configured to measure a relative twist of the drive unit (10), and at least one control unit (30), wherein the control unit (30) has a signal connection to the at least one sensor and is configured to carry out a torque measurement according to the method as claimed in claim 1.

12. A method for measuring the torque of a vehicle drive unit (10), wherein the drive unit (10) comprises at least one bearing for connecting to a fixed support point, the method comprising providing at least one sensor that measures a relative twist of the drive unit (10), and determining a torque that is applied to the drive unit (10) as a measurement value from the sensor value.

13. The method as claimed in claim 1, characterized in that the measurement value is determined from the sensor value and at least one bearing characteristic value, wherein the bearing characteristic value is a tensile, bending and/or torsional rigidity.

14. The method as claimed in claim 1, characterized in that the at least one sensor is a capacitive sensor, optical sensor or acoustic sensor.

15. The method as claimed in claim 1, characterized in that the at least one sensor is an acceleration sensor or a Hall sensor, whereby a relative angular position of the drive unit (10) can be determined.

16. The method as claimed in claim 1, characterized in that at least one sensor is disposed on a differential gearbox (12).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In the following figures, the identical reference characters are used for the same technical features, even of different exemplary embodiments. In the figures:

[0019] FIG. 1 shows schematically a first embodiment of the measuring system according to the invention and

[0020] FIG. 2 shows schematically a further embodiment of the measuring system according to the invention.

DETAILED DESCRIPTION

[0021] In FIG. 1, a possible embodiment of the measuring system 100 according to the invention is shown, wherein the measuring system 100 comprises a first sensor 22 that is immovably connected to a bearing 23 of the drive unit 10 with a fixed support point 24. The bearing 23 is in this case essentially embodied elastically, so that in the event of a torque produced by the drive unit 10, a relative change in position, in particular a relative twist about the bearing 23, can be achieved. Moreover, the drive unit 10 in FIG. 1 comprises a second elastic bearing 20 that is connected to the fixed support point 21. A second sensor 25 that is disposed on the drive unit 10 is embodied as a distance sensor 25 and measures a relative change in the position of the drive unit 10. The distance sensor 25 measures the relative change in the position As between the reference point RP and the measurement point MP. In this case, the reference point RP forms the comparison value that represents the position of the drive unit 10 without an applied torque. If the drive unit 10 now produces a torque, which is represented by the arrow in the drive unit 10, then the torque produces a relative change in the position of the drive unit 10 about the two bearings 20 and 23. In this case, on the one hand a tensile force on the sensor 22 can be measured, which is produced by a displacement of the drive unit 10 as a result of the torque. At the same time, the drive unit 10 moves by the relative change in position As, so that the two sensor values from the sensor 22 and the sensor 25 can be used for the determination of the produced torque. The sensors 22 and 25 in FIG. 1 have a signal connection to the control unit 30. In this case, the control unit 30 carries out the method according to the invention for measuring the torque of the drive unit 10 and thus determines the torque produced based on the sensor values of the sensors 25 and 22 in combination with the known bearing characteristic values of the bearings 20 and 23. By way of example, the support points 21 and 24 represent the body of a vehicle, so that they are fixed reference points for the measurement of the relative change in position and/or change in force. The drive unit 10 in FIG. 1 represents a vehicle drive unit by way of example, in particular a drive machine or a differential gearbox.

[0022] FIG. 2 shows a drive unit 10 comprising a drive machine 11 and a differential/gearbox 12 for the drive of a vehicle. The drive machine 11 is connected by means of two bearings 20 and the bearing 23 to the body 21, 24 as fixed support points. Moreover, a distance sensor 22 is disposed on the drive machine 11 that measures the distance As of the drive machine 11 from the fixed support point 24. The distance As changes in the event of an applied torque, so that said change can be measured by the sensor 22. Moreover, an acceleration sensor 25 is disposed on the drive machine 11 and on the fixed support point 24 respectively that measures the acceleration of the drive machine 11 or the fixed support point and detects a relative change in position thereof. In this case, the arrow in the sensors 25 indicates the acceleration vector. Two acceleration sensors 25 are provided here, wherein a positionally fixed sensor 25 and a sensor 25 that is disposed on the drive machine 11 are provided. The positionally fixed sensor 25 is disposed on the fixed support point 24 in this case and forms a reference system for the measurement. As a result of an applied torque, the measurement value of the variable position sensor 25 on the drive machine 11 changes as a result of twisting of the drive unit 10. The torque can be determined using the changed measurement value and the measurement value of the reference system. The applied torque can be derived from the differing values for a.sub.x and a.sub.y by using the assumed torsional rigidity of the bearing 20, 23. The drive unit 10 comprises a differential 12 in FIG. 2, with which a torque of the drive machine 11 can be transmitted to a drive axle 13 by means of the differential 12. If a torque is applied to the differential 12 and accordingly to the drive axle 13, then the distance As from the drive axle 13 to the fixed support point 24 changes. Said distance As is measured by the sensor 22 on the fixed support point 24, so that the torque applied to the differential 12 or the drive axle 13 can be determined.

[0023] The above descriptions of the embodiment describe the present invention exclusively within the context of examples. Of course, individual features of the embodiment, if technically meaningful, can be freely combined without departing from the scope of the present invention.