US 12,221,176 B2
Electric power steering device
Takanori Tatebe, Tokyo (JP); Shunsuke Watanabe, Tokyo (JP); Toshikuni Nagatani, Tokyo (JP); and Masatsugu Suzuki, Tokyo (JP)
Assigned to SUBARU CORPORATION, Tokyo (JP)
Filed by SUBARU CORPORATION, Tokyo (JP)
Filed on Jun. 24, 2022, as Appl. No. 17/849,251.
Claims priority of application No. 2021-111175 (JP), filed on Jul. 4, 2021.
Prior Publication US 2023/0001980 A1, Jan. 5, 2023
Int. Cl. B62D 5/04 (2006.01)
CPC B62D 5/0463 (2013.01) [B62D 5/0481 (2013.01)] 4 Claims
OG exemplary drawing
 
2. An electric power steering device comprising:
a motor configured to impart an assist force to a steering device that is to steer a steerable wheel of a vehicle;
a motor controller configured to control an output of the motor;
a first power source circuit configured to supply electric power from a power source to at least one electric load other than the motor controller when a main power source of the vehicle is on;
a second power source circuit configured to supply electric power continually from the power source to the motor;
a power source switching circuit configured to switch between a first state and a second state, the first state being a state in which electric power is supplied from the first power source circuit to the motor controller while the second power source circuit and the motor controller are cut off from one another, the second state being a state in which electric power is supplied from the second power source circuit to the motor controller while the first power source circuit and the motor controller are cut off from one another; and
a current detector configured to detect an operating current of the motor, wherein
the power source switching circuit is configured to select the first state in a case where the operating current of the motor is less than or equal to a predetermined value, and select the second state in cases other than the case.