Method and device for determining torque in an automotive power window system

• US 6,304,048 B1
• Filed: 09/07/1999
• Issued: 10/16/2001
• Est. Priority Date: 09/07/1999
• Status: Expired due to Fees

• Current Assignee: Meritor Light Vehicle Systems, Inc. (Cummins Incorporated)
• Original Assignee: Meritor Light Vehicle Systems, Inc. (Cummins Incorporated)
• Inventors: Kyrtsos, Christos, Breynaert, Francois, Hopson, Charles, Davies, Timothy, Tyckowski, Joseph, Bonduel, Pascal
• Primary Examiner(s): Ro, Bentsu
• Application Number:
  US09/390,888
• Time in Patent Office: 770 Days
• Field of Search: 318/646, 318/647, 318/648, 318/652, 318/256, 318/264, 318/265, 318/266, 318/283, 318/286, 318/432, 318/434, 318/466, 318/468, 318/469, 318/474, 318/475, 49/26
• US Class Current: 318/475
• CPC Class Codes: E05F 15/41 Detection by monitoring transmitted force or torque E05F15/48 takes precedence; Safety couplings with activation dependent upon torque or force, e.g. slip couplings
• CPC Class Codes: E05F 15/603 using rotary electromotors
• CPC Class Codes: E05Y 2201/438 Rotors
• CPC Class Codes: E05Y 2201/476 Disk springs
• CPC Class Codes: E05Y 2400/55 by using load sensors
• CPC Class Codes: E05Y 2600/11 by automatically acting means
• CPC Class Codes: E05Y 2600/31 Linear motion
• CPC Class Codes: E05Y 2800/21 of identical elements, e.g. of identical compression springs
• CPC Class Codes: E05Y 2900/55 Windows
• CPC Class Codes: H02H 7/0851 for motors actuating a movable member between two end positions, e.g. detecting an end position or obstruction by overload signal
• CPC Class Codes: H02H 7/093 against increase beyond, or decrease below, a predetermined level of rotational speed centrifugal switches H01H35/10

Abstract

A method and device for determining torque applied to a motor of an automotive power window system includes a motor having a rotor mounted on a rotor shaft wherein the rotor and rotor shaft move linearly along an axial length of the rotor shaft in response to an applied torque. A ring magnet is mounted on the rotor shaft for generating a magnetic field as the rotor shaft rotates. A sensor, in communication with the ring magnet, senses a strength of the magnetic field based on a linear position of the ring magnet in relation to the sensor and generates a proportional voltage signal. A control circuit receives the voltage signal and detects a torque applied to the motor in response thereto.

Claims

1. A method for detecting torque applied to a motor of an automotive power window system, the motor having a rotor mounted on a rotor shaft, the rotor and rotor shaft being allowed to move linearly along an axial length of the rotor shaft in response to an applied torque, the method comprising:

generating a magnetic field in response to a rotation of the rotor shaft;

sensing a strength of the magnetic field based on the linear position of the rotor shaft; and

detecting a torque applied to the motor based on the strength of the magnetic field.

2. The method as recited in claim 1 wherein sensing the strength of the magnetic field further comprises generating a voltage signal proportional to the strength of the magnetic field.

3. The method as recited in claim 1 further comprising controlling the motor in response to detecting the torque.

4. The method as recited in claim 3 wherein controlling the motor includes stopping the motor.

5. The method as recited in claim 3 wherein controlling the motor includes reversing the motor.

6. The method as recited in claim 1 wherein detecting the torque further includes determining a direction of the torque based on the strength of the magnetic field and the linear position of the rotor shaft.

7. A device for driving an automotive power window system comprising:

a motor having a rotor mounted on a rotor shaft, the rotor and rotor shaft being allowed to move linearly along an axial length of the rotor shaft in response to an applied torque;

a ring magnet mounted on the rotor shaft for generating a magnetic field as the rotor shaft rotates;

a sensor in communication with the ring magnet for sensing a strength of the magnetic field based on a linear position of the ring magnet in relation to the sensor and generating a voltage signal proportional thereto; and

a control circuit for receiving the voltage signal and detecting a torque applied to the motor in response thereto.

8. The device as recited in claim 7 wherein the control circuit is further operative to control the motor in response to detecting the torque.

9. The device as recited in claim 8 wherein the control circuit, in controlling the motor, is further operative to stop the motor.

10. The device as recited in claim 8 wherein the control circuit, in controlling the motor, is further operative to reverse the motor.

11. The device as recited in claim 7 wherein the control circuit is further operative to determine a direction of the torque based on the strength of the magnetic field and the linear position of the rotor shaft.

12. The device as recited in claim 11 wherein in a steady-state mode, the ring magnet is positioned at an end of the sensor rather than at a middle position of the sensor.

13. The device as recited in claim 7 wherein the sensor is a Hall Effect sensor.