SENSOR ASSEMBLY

Abstract

A sensor assembly for an electromechanical steering system of a motor vehicle may include a measuring device and a control device. The measuring device may include a torque sensor unit and an index sensor unit. The torque sensor unit may be connected to the control device by a power supply line to supply said unit with electrical energy. The sensor assembly is configured to transmit an index signal of the index sensor unit to the control device by modulating a signal that is transmittable via the power supply line.

Claims

1-11. (canceled)

12. A sensor assembly for an electromechanical steering system of a motor vehicle, comprising: a measuring device; and a control device, wherein the measuring device comprises a torque sensor unit and an index sensor unit, the torque sensor unit being connected to the control device by a power supply line to supply the torque sensor unit with electrical energy, wherein the sensor assembly is configured to transmit an index signal of the index sensor unit to the control device by modulating a signal that is transmittable via the power supply line.

13. The sensor assembly of claim 12 wherein the torque sensor unit comprises a modulation unit.

14. The sensor assembly of claim 12 wherein the control device is configured to demodulate the index signal that is modulated.

15. The sensor assembly of claim 12 wherein the control device comprises a demodulation unit.

16. The sensor assembly of claim 12 wherein the signal that is transmittable via the power supply line is a signal of an electrical voltage or a signal of an electrical current strength.

17. The sensor assembly of claim 16 wherein the modulation is a modulation of the electrical voltage or a modulation of the electrical current strength.

18. The sensor assembly of claim 12 wherein the modulation is a frequency modulation or an amplitude modulation.

19. The sensor assembly of claim 12 wherein the torque sensor unit comprises at least two torque sensors, wherein the at least two torque sensors are connected to the control device via the power supply line to supply the at least two torque sensors with electrical energy.

20. The sensor assembly of claim 12 configured to operate on direct current.

21. A method for detecting straight-ahead travel of a motor vehicle comprising a steering spindle by way of the sensor assembly of claim 12, the method comprising: providing a torque signal by way of the torque sensor unit; providing an index signal by way of the index sensor unit; transmitting the torque signal to the control device; transmitting the index signal via the power supply line to the control device by modulation; and detecting straight-ahead travel based on the torque signal and the index signal.

22. The method of claim 21 wherein transmitting the index signal comprises: modulating the index signal provided onto the signal that is transmittable via the power supply line; transmitting the modulated signal that is transmittable via the power supply line to the control device; and demodulating the index signal.

Description

DESCRIPTION OF THE DRAWINGS

[0025] Advantageous embodiments of the invention are described in more detail below by reference to the drawings. Taken individually, in the drawings:

[0026] FIG. 1 shows an embodiment of a sensor assembly according to the invention in a block diagram,

[0027] FIG. 2 shows an electromechanical steering system having the sensor assembly according to the invention in a perspective view,

[0028] FIG. 3 shows an embodiment of the measuring device of the sensor assembly according to the invention in a block diagram and

[0029] FIG. 4 shows an embodiment of the control device of the sensor assembly according to the invention in a block diagram.

EMBODIMENTS OF THE INVENTION

[0030] In the various figures, identical parts are always labeled with the same reference signs and are therefore usually named or mentioned only once in each case.

[0031] FIG. 1 shows an embodiment of a sensor assembly 1 according to the invention in a block diagram.

[0032] The sensor assembly 1 is suitable for an electromechanical steering system of a motor vehicle. The sensor assembly 1 comprises a measuring device 2 and a control device 3, with the measuring device 2 comprising a torque sensor unit 4 and an index sensor unit 5. The torque sensor unit 4 is connected to the control device 3 via a power supply line 6 to supply electrical energy to the sensor unit. The power supply line 6 is designed as an electrical power lead. The sensor assembly 1 is designed to transmit an index signal of the index sensor unit 5, i.e. a signal generated by the index sensor unit 5, to the control device 3 by modulating a signal that can be transmitted via the power supply line 6. Since the power supply line 6 in this case is an electrical power lead, the signal to be transmitted via the power supply line 6 is an electrical current signal. The modulation is a modulation of the electrical current strength. The torque sensor unit 4 and the index sensor unit 5 are each connected to the control device 3 via a ground lead 7.

[0033] The control device 3 comprises a control unit 8 designed as a microprocessor, and a demodulation unit 9. The demodulation unit 9 is connected via the power supply line 6 and via the ground lead 7 to the measuring device 2, more precisely to the torque sensor unit 4 and the index sensor unit 5. In addition, the demodulation unit 9 is connected to the control unit 8 via a lead 10 designed as a cable or conductor track. The demodulation unit 9 is designed to receive and demodulate the signal that can be transmitted via the power supply line 6, i.e. to recreate the index signal previously modulated onto the electrical current signal for further processing.

[0034] The torque sensor unit 4 comprises two torque sensors 11, 12, namely a first torque sensor 11 and a second torque sensor 12. The first torque sensor 11 and the second torque sensor 12 are connected to the control device 3 via the power supply line 6 to supply said sensors with electrical energy. The two torque sensors 11, 12 are designed redundantly with respect to each other. If a fault or even failure of the first torque sensor 11 is detected, the second torque sensor 12 can thus start or take over operation to replace it—or vice versa. The two torque sensors 11, 12 are each connected to the control unit 8 via leads 13, 14 formed as cables or conductor tracks. The two torque sensors 11, 12 transmit the respective torque signals to the control unit 8 via the leads 13, 14. The index sensor unit 5 comprises an index sensor 15, which is designed as a Hall-effect sensor.

[0035] FIG. 2 shows an electromechanical steering system having the sensor assembly 1 in a perspective, simplified oblique frontal view in the direction the vehicle is traveling, where non-essential components are not shown for the sake of clarity. Apart from the steering system shown in FIG. 2, however, it is also conceivable and possible to provide the sensor assembly according to the invention in a steer-by-wire steering system.

[0036] The steering system comprises a steering column 16 with a steering spindle 17. The steering column 16 is mechanically coupled to the steered wheels 19 of the motor vehicle via a steering gearbox 18. The steering gearbox 18 comprises a pinion 20 and a toothed coupling rod 21, wherein the steering gearbox 18 is used to translate a rotational movement of the pinion 20 into a translational movement of the coupling rod 21 along its longitudinal axis. At the end of the steering column 16 facing the driver, a steering wheel 22 is attached for entering a driver's steering request or command, wherein the driver can turn the steering wheel 22 in the usual manner to enter their steering request. The coupling rod 21, which moves linearly along its longitudinal axis, is mechanically coupled on both sides of the motor vehicle with a track rod 23. The track rods 23 are in turn each mechanically coupled to the vehicle wheels 19.

[0037] FIG. 3 shows an embodiment of the measuring device 2 of the sensor assembly 1 according to the invention which comprises the torque sensor unit 4 and the index sensor unit 5, in a block diagram with a partially indicated steering spindle 17.

[0038] The index sensor unit 5 comprises an index sensor 15, which is designed as a Hall-effect sensor. The index sensor unit 5 is arranged in immediate proximity to the steering spindle 17. The steering spindle 17 has a defined point 24 in the circumferential direction, in the form of a metallic elevation. The index sensor unit 5 is designed to detect a condition in which the spatial distance to the defined point 24 is a minimum or falls below a defined threshold value. When the index sensor unit 5 detects such a condition, it generates an index pulse that forms an index signal. The index pulse is a momentary increase in the current consumption of the index sensor unit 5. In other words: The index pulse corresponds to a momentary increase in the current consumption from an initial value, i.e. an activation of the index sensor unit 5 or of the index sensor 15, followed by a decrease in the current consumption back to the original value, i.e. a deactivation of the index sensor unit 5 or of the index sensor 15.

[0039] The torque sensor unit 4 comprises a torque sensor 11. The torque sensor unit 4 can transmit the torque signal to the control device 3 via the lead 13. The torque sensor unit 4 and the index sensor unit 5 are connected by leads 25, 26 designed as cables or conductor tracks, which enable power to be transmitted or supplied to the torque sensor unit 4. The increase and decrease of the current consumption of the index sensor unit 5 corresponds to a modulation of the index signal onto the signal that can be transmitted via the power supply line 6 designed as a power lead, which signal is then transmitted to the control device 3. A separate signal lead is not required to transmit the index signal to the control device 3. This is because the index signal can be transmitted to the control device 3 via the power supply line 6 in a form in which it is modulated onto the current signal.

[0040] FIG. 4 shows a block diagram of an embodiment of the control device 3 of the sensor assembly 1 according to the invention, which comprises the control unit 8.

[0041] The control device 3 is designed to receive a plurality of different signals, on the basis of which the detection of straight-ahead driving is carried out. For example, the control device 3 is designed to receive and process index signals, torque signals, vehicle speed signals, vehicle acceleration signals, and/or time-based signals.

LIST OF REFERENCE SIGNS

[0042] 1 sensor assembly

[0043] 2 measurement device

[0044] 3 control device

[0045] 4 torque sensor unit

[0046] 5 index sensor unit

[0047] 6 power supply line

[0048] 7 ground lead

[0049] 8 control unit

[0050] 9 demodulation unit

[0051] 10 lead

[0052] 11 torque sensor

[0053] 12 torque sensor

[0054] 13 lead

[0055] 14 lead

[0056] 15 index sensor

[0057] 16 steering column

[0058] 17 steering spindle

[0059] 18 steering gearbox

[0060] 19 vehicle wheel

[0061] 20 pinion

[0062] 21 coupling rod

[0063] 22 steering wheel

[0064] 23 track rod

[0065] 24 defined point

[0066] 25 lead

[0067] 26 lead