Brake apparatus

A brake apparatus comprising:

• a piston body made of a resin material and disposed in a closed-ended bore formed in a housing, the closed-ended bore being communicated with a fluid passage formed within the housing, the piston body being moved in the closed-ended bore in an axial direction thereof when anti-lock brake system control is executed,
• a plate member fixed to a piston crown surface of the piston body, the plate member having a wear resistance higher than that of the resin material of the piston body,
• a first elastic member that biases the piston body toward a closed end of the bore;
• and
• a pressure regulating valve disposed in the fluid passage, the pressure regulating valve comprising a valve element, a seat portion that is brought into contact with the valve element, a rod disposed between the plate member and the valve element, the rod acting to move the valve element apart from the seat portion, and a second elastic member having one end contacted with the valve element and biasing the valve element toward the seat portion, the second elastic member having an elastic force smaller than that of the first elastic member.

A brake apparatus comprising:

• a piston body made of a resin material and disposed in a closed-ended bore formed in a housing, the closed-ended bore being communicated with a fluid passage formed within the housing,
• a plate member made of metal and disposed on a piston crown surface of the piston body, the plate member being integrally formed with the piston body,
• a coil spring that biases the piston body toward a closed end of the bore;
• and
• a pressure regulating valve disposed in the fluid passage, the pressure regulating valve comprising a valve element, a seat portion that is brought into contact with the valve element, a rod made of metal and disposed between the plate member and the valve element, the rod acting to move the valve element apart from the seat portion, and an elastic member having one end contacted with the valve element and biasing the valve element toward the seat portion, the elastic member having an elastic force smaller than a biasing force of the coil spring, the valve element being spaced apart from the seat portion in a non-operating condition of the pressure regulating valve,
• wherein the brake apparatus has a reservoir function of reserving brake fluid flowed from a wheel cylinder of a vehicle in the closed-ended bore by strokes of the piston body when anti-lock brake system control is executed,
• the piston body has a closed-ended cylindrical shape having a closed end that supports one end of the coil spring, and
• the plate member has a diameter larger than an outer diameter of the coil spring.