Brake apparatus

A brake apparatus comprising:

• a housing;
• a pair of closed-ended bores formed in the housing;
• a pair of piston bodies, each disposed within a respective closed-ended bore formed in the housing;
• a first elastic member configured to bias a piston body toward a closed end of a respective bore;
• a pair of fluid passages, wherein each fluid passage is opened to the closed end of a respective bore, wherein each fluid passage has a diameter smaller than a diameter the respective bore, and wherein the pair of fluid passages are formed to be offset from respective central axes of the piston bodies in such a direction that the pair of fluid passages are spaced apart from each other;
• a pair of pressure regulating valves, each disposed in a respective fluid passage, and each pressure regulating valve including:
• a valve element,
• a seat portion brought into contact with the valve element,
• a rod disposed between a crown surface of a respective piston body and the valve element, the rod configured 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;
• and
• a rotary gear pump configured to suck brake fluid through the pair of pressure regulating valves, wherein the rotary gear pump is disposed in a region between the pair of pressure regulating valves;
• wherein the piston body is a resin-molded member and has a hard member on a crown surface thereof, the hard member having a hardness larger than that of a resin material of the piston body, and the piston body and the rod are brought into contact with each other via the hard member.

A brake apparatus comprising:

• a housing;
• a pair of closed-ended bores formed in the housing;
• a pair of piston bodies, each disposed within a respective bore;
• a pair of retainers, each fixed to an open end portion of a respective bore;
• a first elastic member retained between the retainer and a piston body, and configured to bias the piston body toward a closed end of the respective bore;
• a pair of fluid passages, each opened to the closed end of a respective bore;
• a pair of pressure regulating valves, each disposed in a respective fluid passage, each pressure regulating valve including:
• a valve element,
• a seat portion brought into contact with the valve element,
• a rod disposed between a crown surface of the respective piston body and the valve element, the rod configured 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 rotary gear pump configured to suck brake fluid through the pair of pressure regulating valves;
• and
• a motor mounted to a front surface of the housing, and configured to drive the rotary gear pump;
• a pair of small-diameter fluid passages, wherein each small-diameter fluid passage has a diameter smaller than that of a respective fluid passage to which the small-diameter fluid passage is connected, wherein each small-diameter fluid passage is connected to a reduced diameter portion of the respective fluid passage, and wherein each small-diameter fluid passage is arranged in series with respect to the respective fluid passage,
• a seat member fixedly disposed within the respective fluid passage, and formed with the seat portion;
• a closed-ended cylindrical filter member fixed to the seat member and retaining the other end of the second elastic member, the closed-ended cylindrical filter member including a plurality of projecting portions formed on a crown surface of the closed-ended cylindrical filter member, wherein each projecting portion is engaged with a respective reduced diameter portion to allow the brake fluid to flow from the respective small-diameter fluid passage to the respective fluid passage;
• wherein when viewed from a side surface of the housing, the rotary gear pump is disposed in a region between the pair of fluid passages;
• wherein the pair of fluid passages are formed to be offset from respective central axes of the piston bodies in such a direction that the pair of fluid passages are spaced apart from each other;
• wherein the rotary gear pump is disposed in a region between the pressure regulating valves;
• and
• wherein the respective fluid passages have a diameter smaller than a diameter of the respective bores.