Sensor module for a master cylinder

Patent metadata

Field	Value
Publication number	US-9266517-B2
Application number	US-201113810241-A
Country	US
Kind code	B2
Filing date	Jul 15, 2011
Priority date	Jul 16, 2010
Publication date	Feb 23, 2016
Grant date	Feb 23, 2016

Abstract

A sensor assembly for use with a master cylinder is described. The master cylinder comprises an input-side activation element to which a signal transmitter element is coupled. The sensor module comprises a travel sensor for sensing travel carried out by the activation element, and a position sensor for sensing when a predefined position of the activation element is reached.

First claim

The invention claimed is:

1. A sensor assembly for use with a master cylinder, which master cylinder has an input-side actuating element, a signal transmitter element detectable by sensors being coupled to the actuating element, and the sensor assembly comprising:
a travel sensor for sensing travel performed by the actuating element;
a position sensor for sensing when a predefined position of the actuating element is reached; and
a circuit device which is designed to calibrate the travel sensor, when the position sensor senses the predefined position, by referring an output signal of the travel sensor to a reference signal and adjusting the output signal of the travel sensor to the reference signal.

2. A sensor assembly according to claim 1 , the travel sensor providing an analog signal.

3. A sensor assembly according to claim 1 , the position sensor providing a binary signal.

4. A sensor assembly according to claim 1 , the travel sensor and the position sensor being at a distance from one another and the distance being chosen in dependence on a linear extension of the signal transmitter element.

5. A sensor assembly according to claim 4 , the distance between the travel sensor and the position sensor corresponding to approximately half the length of the signal transmitter element.

6. A sensor assembly according to claim 1 , the travel sensor and the position sensor being designed to sense a magnetic flux density.

7. A sensor assembly according to claim 6 , the travel sensor being placed in such a manner that, in a starting position of the actuating element, the travel sensor lies approximately in a region of a first flux density maximum.

8. A sensor assembly according to claim 1 , the sensor assembly comprising a further travel sensor.

9. A sensor assembly according to claim 8 , the further travel sensor being placed in such a manner that, in a starting position of the actuating element, the further travel sensor lies approximately in a region of a second flux density maximum.

10. A sensor assembly according to claim 1 , the position sensor being placed in such a manner that, in a starting position of the actuating element, the position sensor lies approximately in a region between two flux density maxima.

11. A sensor assembly according to claim 1 , the position sensor being part of a stop light switch.

12. A sensor assembly according to claim 1 , the travel sensor and the position sensor being selected from a sensor group comprising the following sensors: Hall sensor, AMR sensor, GMR sensor, CMR sensor, Reed relay.

13. A sensor assembly according to claim 1 , further comprising
a vacuum sensor for sensing a vacuum in a vacuum region, provided for communication with a vacuum brake booster, of the master cylinder; and
a housing which accommodates the vacuum sensor, the travel sensor and the position sensor, the housing having a housing opening which permits a communication of the vacuum sensor with the vacuum region of the master cylinder, and a fastening arrangement for mounting the housing on the outside of the master cylinder.

14. A master cylinder assembly, comprising
a master cylinder which has the input-side actuating element, a signal transmitter element coupled to the actuating element of the master cylinder and detectable by sensors being provided; and
a sensor assembly according to claim 1 .

15. A master cylinder assembly according to claim 14 , further comprising a plunger coupled to the actuating element of the master cylinder, the plunger carrying the signal transmitter element.

16. A method for operating a sensor assembly for use in combination with a master cylinder, which master cylinder has an input-side actuating element, to which a signal transmitter element detectable by sensors is coupled, the sensor assembly comprising a travel sensor and a position sensor and the method comprising the following steps:
sensing a travel performed by the actuating element by means of the travel sensor;
sensing when a predefined position of the actuating element is reached by means of the position sensor; and
calibrating the travel sensor, when the predefined position is sensed, by referring an output signal of the travel sensor to a reference signal and adjusting the output signal of the travel sensor to the reference signal.

17. The method according to claim 16 , comprising comparing the travel performed and when the predefined position is reached.

18. The method according to claim 16 , comprising running a plausibility check on the output signal of the position sensor.

19. The method according to claim 18 , the running of the plausibility check on the output signal of the position sensor comprising a redundant evaluation of another signal indicating a braking procedure.

20. The method according to claim 16 , comprising determining a brake pedal travel on the basis of the output signal of the travel sensor.

21. The method according to claim 16 , comprising determining a vacuum in a vacuum brake booster on the basis of the output signal of the travel sensor.

Assignees

• Knechtges Josef
• Naether Niko
• Baron Thomas
• Schaust Karl-Heinz
• Ullmer Klaus
• Lucas Automotive Gmbh

Inventors

• Knechtges Josef
• Naether Niko
• Baron Thomas
• Schaust Karl-Heinz
• Ullmer Klaus

Classifications

• B60T11/16

  Master control, e.g. master cylinders (master cylinders associated with vacuum boosters B60T13/565) · CPC title

• G01L5/28

  for testing brakes · CPC title

• B60T17/22 Primary

  Devices for monitoring or checking brake systems; Signal devices · CPC title

• B60T13/52

  indirect, i.e. vacuum booster units · CPC title

• B60T7/042 Primary

  by electrical means, e.g. using travel or force sensors · CPC title