Braking device

A braking device comprising:

• a reservoir tank configured to store a brake fluid;
• an electric cylinder configured to discharge the brake fluid by moving a piston in the cylinder in response to driving by an electric motor;
• a hydraulic pressure sensor configured to detect a hydraulic pressure of the brake fluid discharged by the electric cylinder;
• and
• a control unit configured to control the electric motor,
• the braking device being configured to generate a braking force on a wheel by supplying the brake fluid to a wheel cylinder in response to discharge of the brake fluid from the electric cylinder, wherein
• the electric cylinder includes a hydraulic chamber defined by a peripheral wall of the cylinder and the piston, an input port that is an inlet for the brake fluid from the reservoir tank to the hydraulic chamber, and an output port that is an outlet for the brake fluid from the hydraulic chamber,
• the electric cylinder is configured such that, when a moving direction of the piston for reducing a volume of the hydraulic chamber is defined as a forward direction, a direction opposite to the forward direction is defined as a retreat direction and a furthest position in the retreat direction in a movable range of the piston is defined as a retreat limit position, the input port is opened when the piston is positioned at the retreat limit position, and when the piston is moved in the forward direction from the retreat limit position and the input port is closed, the hydraulic pressure in the hydraulic chamber increases and the brake fluid is discharged from the output port,
• the braking device further comprises a release flow path configured to establish communication between the output port and the reservoir tank without passing through the hydraulic chamber, and a release valve configured to open and close the release flow path,
• the control unit holds the piston at a standby position set between a position where the input port is switched between a closed state and an opened state and the retreat limit position when generation of the braking force is not requested, and controls the electric motor to move the piston in the forward direction from the standby position when the generation of the braking force is requested, and
• the control unit executes calibration processing of executing output calibration for the hydraulic pressure sensor in a state where the release valve is opened.