Fluid-pressure pump

Abstract

A fluid-pressure pump operated by a drive force of an electric motor is configured compact. A cam mechanism and a pump portion are disposed coaxial with a rotational axis of an output shaft of an electric motor. A cam mechanism includes a rotational member rotating in unison with the output shaft and a cam member having a cam face to which the rotational member comes into contact. The pump portion includes a piston which reciprocates in unison with the cam member and a spring for operating the piston in a reverse direction. At the time of rotation of the output shaft, the cam mechanism operates the piston in the forward direction by a pressing force applied from the rotational member to the cam face, and the spring, with its urging force, operates the piston in the reverse direction.

1 . A fluid-pressure pump comprising:
 a piston mounted coaxially on a rotational axis of an output shaft of an electric motor to be reciprocatable along the rotational axis;   a cam mechanism converting a rotational force of the output shaft into a pressing force along a direction of the rotational axis for operating the piston in a forward direction; and   a spring operating the piston in a reverse direction opposite the forward direction;   wherein the cam mechanism includes a rotational member rotatable in unison with the output shaft and a cam member having a cam face to which the rotational member comes into contact, the cam member being non-rotatable about the rotational axis and being reciprocatable along the rotational axis.   
     
     
         2 . The fluid-pressure pump according to  claim 1 , wherein:
 a plurality of said rotational members are disposed at a plurality of positions in a circumferential area about the rotational axis;   the cam member includes the cam face to which the plurality of rotational members come into contact simultaneously; and   when the plurality of rotational members are rotated, a direction of a resultant force combining component forces applied from the plurality of rotational members to the cam member is set on the rotational axis.   
     
     
         3 . The fluid-pressure pump according to  claim 2 , wherein a shape of the cam face when the cam member is developed in a circumferential direction is waveform. 
     
     
         4 . The fluid-pressure pump according to  claim 2 , wherein the cam face includes a reverse-side cam face for operating the piston in the reverse direction and a forward-side cam face for applying a pressing force to the piston in the forward direction, the reverse -side cam face having a steeper slope than the forward-side cam face.