An EPB (Electronic Parking Brake) apparatus may include: a housing unit; a motor unit mounted in the housing unit; a worm wheel gear unit engaged and rotated with the motor unit; a piston unit connected with a brake shoe; and a nut unit mounted on the worm wheel gear unit, coupled to the piston unit, and moved by the rotation of the worm wheel gear unit so as to pressurize the piston unit. The housing unit is deformed by the movement of the piston unit and restricts the operation of the motor unit.

An EPB (Electronic Parking Brake) apparatus may include: a housing unit; a motor unit mounted in the housing unit; a worm wheel gear unit engaged and rotated with the motor unit; a piston unit connected with a brake shoe; and a nut unit mounted on the worm wheel gear unit, coupled to the piston unit, and moved by the rotation of the worm wheel gear unit so as to pressurize the piston unit. The housing unit is deformed by the movement of the piston unit and restricts the operation of the motor unit.

An EPB (Electronic Parking Brake) apparatus may include: a housing unit; a motor unit mounted in the housing unit; a worm wheel gear unit engaged and rotated with the motor unit; a piston unit connected with a brake shoe; and a nut unit mounted on the worm wheel gear unit, coupled to the piston unit, and moved by the rotation of the worm wheel gear unit so as to pressurize the piston unit. The housing unit is deformed by the movement of the piston unit and restricts the operation of the motor unit.

A reverse input blocking clutch has: a pressed member having a pressed surface; an input member having an input-side engaging portion; an output member having an output-side engaging portion; and an engaging element having an engaging element main body and a link member to move in the first direction away from or toward the pressed surface. The engaging element main body has a pair of main body plates arranged to overlap in the axial direction, and a pivot support shaft arranged on the side in the first direction closer to the pressed surface than the input-side engaging portion with the both side portions supported by the pair of main body plates. One pressing surface facing the pressed surface is provided on one main body plate, and the other pressing surface is provided on the other main body plate.

A reverse input blocking clutch has: a pressed member having a pressed surface; an input member having an input-side engaging portion; an output member having an output-side engaging portion; and an engaging element having an engaging element main body and a link member to move in the first direction away from or toward the pressed surface. The engaging element main body has a pair of main body plates arranged to overlap in the axial direction, and a pivot support shaft arranged on the side in the first direction closer to the pressed surface than the input-side engaging portion with the both side portions supported by the pair of main body plates. One pressing surface facing the pressed surface is provided on one main body plate, and the other pressing surface is provided on the other main body plate.

A distance (D.sub.1) between a rotation center (O) of an input member (3) and a contact portion (P.sub.in) between an input side engaging portion (9) and an input side engaged portion (17) in a second direction is set to be shorter than a distance (D.sub.2) between a rotation center (O) of an output member (4) and a contact portion (P.sub.out) between an output side engaging portion (12) and an output side engaged portion (14) in the second direction in a state in which a pair of pressing surfaces (13) is pressed against a pressed surface (6) in accordance with a rotation of the output member (4) in a predetermined direction and the input side engaging portion (9) engages with the input side engaged portion (17) in accordance with a rotation of the input member (3) in a direction opposite to the predetermined direction. In a locked or semi-locked state, a contact portion (C.sub.1) between the output side engaging portion (12) and the output side engaged portion (14) is located on the side closer to the rotation center (O) of the output member (4) in a first direction in relation to a virtual line (L) connecting the rotation center (O) of the output member (4) and a contact portion (C.sub.2) between one pressing surface (13) of the pair of pressing surfaces (13) and the pressed surface (6).

A reverse input blocking clutch has: a pressed member having a pressed surface; an input member having an input-side engaging portion; an output member having an output-side engaging portion; and an engaging element having an engaging element main body and a link member to move in the first direction away from or toward the pressed surface. The engaging element main body has a pair of main body plates arranged to overlap in the axial direction, and a pivot support shaft arranged on the side in the first direction closer to the pressed surface than the input-side engaging portion with the both side portions supported by the pair of main body plates. One pressing surface facing the pressed surface is provided on one main body plate, and the other pressing surface is provided on the other main body plate.

A reverse input blocking clutch has: a pressed member having a pressed surface; an input member having an input-side engaging portion; an output member having an output-side engaging portion; and an engaging element having an engaging element main body and a link member to move in the first direction away from or toward the pressed surface. The engaging element main body has a pair of main body plates arranged to overlap in the axial direction, and a pivot support shaft arranged on the side in the first direction closer to the pressed surface than the input-side engaging portion with the both side portions supported by the pair of main body plates. One pressing surface facing the pressed surface is provided on one main body plate, and the other pressing surface is provided on the other main body plate.

An EPB (Electronic Parking Brake) apparatus may include: a housing unit; a motor unit mounted in the housing unit; a worm wheel gear unit engaged and rotated with the motor unit; a piston unit connected with a brake shoe; and a nut unit mounted on the worm wheel gear unit, coupled to the piston unit, and moved by the rotation of the worm wheel gear unit so as to pressurize the piston unit. The housing unit is deformed by the movement of the piston unit and restricts the operation of the motor unit.

An EPB (Electronic Parking Brake) apparatus may include: a housing unit; a motor unit mounted in the housing unit; a worm wheel gear unit engaged and rotated with the motor unit; a piston unit connected with a brake shoe; and a nut unit mounted on the worm wheel gear unit, coupled to the piston unit, and moved by the rotation of the worm wheel gear unit so as to pressurize the piston unit. The housing unit is deformed by the movement of the piston unit and restricts the operation of the motor unit.