Range switching device

Patent metadata

Field	Value
Publication number	US-9304506-B2
Application number	US-201314078659-A
Country	US
Kind code	B2
Filing date	Nov 13, 2013
Priority date	Nov 19, 2012
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

A range switching device provides a feedback control for rotating a motor toward a target rotation position. When a target shift range is switched, the range switching device rotates the motor toward a target rotation position by sequentially switching power supply phases of the motor based on an encoder count value. When the motor rotates within a predetermined stop range, the feedback control ends and a power supply to the motor is stopped. However, if the motor has not rotated to the target rotation position after a predetermined time has elapsed from the stopping of the power supply to the motor, an open drive is performed, in which the power supply phase of the motor is sequentially switched by open-loop control and the motor is rotated in small and/or minute steps toward the target rotation position. In such manner, position accuracy of the shift range switching is improved.

First claim

What is claimed is:

1. A range switching device comprising:
a range switching mechanism having a plurality of range detention concave parts;
a motor driving the range switching mechanism to switch a shift range between a plurality of shift ranges;
a detent mechanism having a latch that selectively engages one of the plurality of range detention concave parts to hold the range switching mechanism at one of the plurality of shift ranges;
an encoder sensing a rotation of the motor and outputting a pulse signal in synchronization with the rotation of the motor; and
a control unit that (i) controls the motor according to a feedback control, when a target shift range is selected, to rotate the motor toward a target rotation position that corresponds to the target shift range, by switching power supply phases of the motor based on a count value of the outputted pulse signal of the encoder, and (ii) ends the feedback control of the motor to stop a power supply to the motor when a rotation position of the motor enters a stop range that includes the target rotation position, wherein
the control unit controls the motor according to an open-loop control to rotate the motor to the target rotation position by sequentially switching the power supply phases of the motor when the motor has not rotated for a predetermined time after the end of the feedback control of the motor, and
the open-loop control by the control unit continues until the rotation position of the motor reaches the target rotation position.

2. The range switching device of claim 1 , wherein
the control unit determines whether the motor has rotated to the target rotation position when the switching of the power supply phases of the motor is performed by the open-loop control, and
the control unit ends the open-loop control to stop the power supply to the motor when the control unit determines that the motor has rotated to the target rotation position.

3. A method for switching a shift range between one of a plurality of shift ranges, the method comprising:
rotating a motor according to a feedback control, when a target shift range is selected, to rotate the motor toward a target rotation position that corresponds to the target shift range, by switching power supply phases of the motor based on a count value of an output signal of an encoder in synchronization with the rotation of the motor;
stopping a power supply to the motor when a rotation position of the motor enters a stop range that includes the target rotation position; and
rotating the motor according to an open-loop control, until the rotation position of the motor reaches the target rotation position, by sequentially switching the power supply phases of the motor, when the motor has not rotated for a predetermined time after stopping the power supply to the motor.

4. The method of claim 3 , wherein the rotating of the motor is performed according to the open-loop control, until the rotation position of the motor reaches the target rotation position, by sequentially switching the power supply phases of the motor, when the motor has not rotated for the predetermined time after the end of the feedback control of the motor and after stopping the power supply to the motor.

5. The method of claim 4 , further comprising
determining whether the motor has rotated to the target rotation position when the switching of the power supply phases of the motor is performed by the open-loop control, and
ending the open-loop control to stop the power supply to the motor upon determination that the motor has rotated to the target rotation position.

Assignees

• Denso Corp

Inventors

• Yoshida Kazuhiro
• Yamada Jun

Classifications

• F16H61/32

  Electric motors  {, actuators or related electrical control means}  therefor · CPC title

• F16H2061/326

  Actuators for range selection, i.e. actuators for controlling the range selector or the manual range valve in the transmission · CPC title

• G05B2219/42095

  First closed loop, then open loop · CPC title

• F16H2061/283

  Adjustment or calibration of actuator positions, e.g. neutral position · CPC title

• G05B19/39 Primary

  using a combination of the means covered by at least two of the preceding groups G05B19/21, G05B19/27 and G05B19/33 · CPC title