Advics Co., Ltd.

Kentaro Yuasa

Tetsuaki Tsuzuki

Yusuke Oshio

Takashi Watanabe

Masatoshi Hanzawa

Kazuma Kondo

Shunsuke Murata

Jin Yamada

Keiichi Shino

Electric parking brake devices are configured such that a parking lever is driven by an electric actuator. The electric actuator is provided with: an electric motor drivable in a forward/reverse direction and operationally controlled by a motor control unit according to rotational loads; a conversion mechanism capable of converting a rotational motion into a linear motion, moving the parking lever from a return position toward an operating position through forward rotation of the electric motor, and moving the parking lever from the operating position toward the return position through the reverse rotation of the electric motor; and a load applying mechanism (a stopper and a disc spring assembly) for applying a predetermined rotational load to the electric motor by driving a constituent member of the conversion mechanism after the parking lever is moved from the operating position to the return position through the reverse rotation of the electric motor.

Electric parking brake device

A brake temperature detection device is configured detect brake temperature more accurately. In a situation in which the temperature in the vicinity of the brake has risen above the atmospheric temperature, indicated by a value read off of the detection signal of the temperature sensor, for example when traveling in congested traffic, a value to correct atmospheric temperature is determined, and atmospheric temperature is corrected on the basis of that atmospheric temperature correction value. Subsequently, brake temperature is calculated on the basis of the corrected air temperature. As a result of this configuration, it is possible to have the calculated brake temperature approach the actual brake temperature. This makes it possible to detect brake temperature more accurately.

Brake temperature detection device and electric parking brake control device

Provided is an electric parking brake device in which a parking lever is driven by an electric actuator. The electric actuator includes: an electric motor which can be rotationally driven in a normal/reverse direction and of which an operation is controlled by a motor control unit in accordance with rotational loads; a converting mechanism which can convert a rotational movement into a linear movement and which can move the parking lever from a returning position to an operating position in accordance with normal rotation of the electric motor and which can move the parking lever from the operating position to the returning position in accordance with reverse rotation of the electric motor; and a load applying mechanism (a stopper, a friction material) which drives components of the converting mechanism and which applies predetermined rotational loads to the electric motor, in a state where the parking lever is moved from the operating position to the returning position in accordance with reverse rotation of the electric motor.

An electronic control device for controlling operations of an electric parking brake and a service brake: determines a release impossible state in which release operation cannot be performed, based on a fact that a motor current that is supplied to an electric motor of the electric parking brake during release control is maintained in a state of a locked rotor current; and performs, when the release impossible state is determined, back-up pressurization for pressing the piston by generating a brake fluid pressure in the wheel cylinder using the service brake and for pressing the friction-applying member against the friction-applied member.

Vehicle brake device

A parking brake control device performs a releasing control with good precision by more precisely maintaining clearance between a friction-applying member and a friction-applied member. During a releasing control, a timing at which a braking force generated by an electric parking brakedrops to zero is detected based on a change in a motor current, and a second releasing operation time is set according to the magnitude of the motor current at the time the braking force drops to zero. This makes it possible for the second releasing operation time to be set in accordance with fluctuations in a motor load due to temperature changes or the like. Therefore, a clearance between a brake pad and a brake disc can be kept constant according to the motor load.

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Tokai, Japan

Kentaro Yuasa