Sensor mounting for power assisted steering system
View Patent ↗A power assisted steering system includes a steering assembly and a power assist assembly. The power assist assembly includes a motor having an output shaft that is connected to the steering assembly. A target disc is connected to the output shaft for rotation therewith. A control unit has a printed circuit board including at least one sensor supported thereon. The sensor is responsive to rotation of the target disc for generating a signal. The controller is responsive to the sensor signal for controlling the operation of the motor.
1. A power assisted steering system comprising:
a steering assembly including a steering shaft; and
a power assist assembly including:
a housing defining first and second portions;
a motor having an output shaft that is connected to said steering assembly;
a target disc connected to said output shaft for rotation therewith;
a control unit having a printed circuit board and disposed in said first portion of said housing;
at least one sensor supported on said printed circuit board and responsive to rotation of said target disc for generating a signal, said controller being responsive to said sensor signal for controlling the operation of said motor; and
a torque sensor disposed in said second portion of said housing adjacent said printed circuit board, said torque sensor being connected to said control unit and generating a signal that is representative of the amount of a torque that is exerted on said steering shaft.
2. The system of claim 1 , wherein said at least one sensor is a non-contact limit switch.
3. The system of claim 2 , wherein said at least one sensor is a Hall effect sensor.
4. The system of claim 1 , wherein said at least one sensor detects rotational speed of said target disc.
5. The system of claim 1 , wherein said at least one sensor detects angular position of said target disc.
6. The system of claim 1 , wherein said at least one sensor detects rotational direction of said target disc.
7. The system of claim 1 , wherein said at least one sensor detects rotational speed and rotational direction of said target disc.
8. The system of claim 1 , wherein said target disc includes a plurality of circumferentially spaced alternating magnetically charged elements.
9. The system of claim 1 , wherein said target disc is press fit onto said output shaft.
10. The system of claim 1 , wherein said motor is mounted in a first housing, and wherein said control unit is mounted in a second housing having an open end facing said motor, said target disc being mounted between said motor and said second housing.
11. The system of claim 1 , wherein said printed circuit board has an opening formed therethrough for the passage of said output shaft.
12. The system of claim 11 , wherein said target disc is positioned between said printed circuit board and said motor.
13. The system of claim 1 , wherein said steering assembly includes a steering shaft, and wherein said power assist assembly further includes a gear assembly connected between said steering shaft and said output shaft for rotational gear reduction.
14. The system of claim 13 , wherein said gear assembly is a direct gearing configuration.
15. The system of claim 13 , wherein said gear assembly is a planetary gearing configuration.
16. The system of claim 13 , wherein said gear assembly includes a belt rotationally connecting said gear assembly to said steering shaft.
17. The system of claim 13 , wherein said steering shaft includes a pinion, and wherein said steering assembly further includes:
a steering assembly housing; and
rack slidably disposed in said housing for connecting with steered wheels of a vehicle, said rack having teeth formed thereon for engagement with said pinion.