Brake actuating apparatus using an electric motor

Abstract

Disclosed is a brake actuating apparatus which can perform braking without converting a rotational motion into a linear motion. The brake actuating apparatus includes a caliper body with a cylinder. An electric motor is fixed to the caliper body. A pressing piston is installed in the cylinder. A housing or plug is installed in and block the cylinder, and a rotational shaft is installed at the center of the housing to be rotated by the motor. A head is attached to the rotational shaft and defines a fluid-receiving space in cooperation with the housing. The rotation of head varies the volume of space, thereby moving the pressing piston.

1 . A brake actuating apparatus, comprising: 
 a caliper body comprising a cylinder, which comprises a first end and a second end;    a piston movably engaged with the cylinder at the first end, wherein at least one of the piston and the caliper body is configured to hold a brake pad;    a shaft rotatable about an axis;    a plug engaged with the cylinder at the second end, the plug comprising a head receiver; and    a head connected to the shaft at a distance from the axis, the head being rotatable about the axis and movable relative to the plug as the shaft rotates about the axis, the head being received by and movably engaged with the head receiver;    wherein the cylinder, the piston and the plug in combination define a first space having a first volume, which is variable depending upon a position of the piston relative to the plug;    wherein the head receiver in combination with the head defines a second space having a second volume, which is variable depending upon the position of the head relative to the plug, the second space being in fluid communication with the first space;    wherein the sum of the first volume and the second volume is substantially constant.    
   
   
       2 . The apparatus of  claim 1 , wherein the head receiver comprises a groove formed in the plug.  
   
   
       3 . The apparatus of  claim 2 , wherein the groove is configured to guide rotational movement of the head about the axis.  
   
   
       4 . The apparatus of  claim 2 , wherein at least part of the head is slidably engaged within the groove.  
   
   
       5 . The apparatus of  claim 2 , wherein the groove has an opening facing the first space.  
   
   
       6 . The apparatus of  claim 2 , wherein the head receiver further comprises a hole extending circumferentially about the axis from the groove, and wherein the head comprises a rod engaged with the hole and slidable relative to the hole.  
   
   
       7 . The apparatus of  claim 6 , wherein the rod has a cross-sectional shape selected from the group consisting of circle, oval and polygon.  
   
   
       8 . The apparatus of  claim 6 , further comprising a sealing ring surrounding the rod.  
   
   
       9 . The apparatus of  claim 2 , wherein the head receiver comprises one or more additional grooves, wherein the groove and the one or more additional grooves are disposed in the plug with the substantially same angular interval between two immediately neighboring grooves.  
   
   
       10 . The apparatus of  claim 1 , further comprising a connector connecting between the shaft and head.  
   
   
       11 . The apparatus of  claim 10 , wherein at least part of the connector is located within the first space.  
   
   
       12 . The apparatus of  claim 10 , wherein at least part of the connector is located between the plug and the piston.  
   
   
       13 . The apparatus of  claim 1 , wherein the second space is defined by one or more walls formed in the plug, and wherein the plug further comprises a passage interconnecting the first and second spaces, the passage enabling the fluid communication between the first and second spaces.  
   
   
       14 . The apparatus of  claim 1 , wherein at least part of the plug is located between the head and the piston.  
   
   
       15 . The apparatus of  claim 1 , wherein the plug comprises a first circular disk having a first radius and a second disk having a second radius, wherein the first and second circular disks are integrated with each other, wherein the first disk faces the first space, and wherein the first radius is smaller than the second radius.  
   
   
       16 . The apparatus of  claim 1 , wherein the plug comprises a through hole extending along the axis and the shaft passes through the through hole.  
   
   
       17 . The apparatus of  claim 1 , further comprising an electric motor attached to the caliper body and configured to rotate the shaft.  
   
   
       18 . The apparatus of  claim 1 , wherein the head is movable between a first position and a second position, wherein the head is configured to rotate in a first rotational direction, stop at a third position and rotate in a second rotational direction which is opposite to the first rotational direction, and wherein the third position is located between the first position and the second position.  
   
   
       19 . An automobile comprising: 
 the apparatus of  claim 1 , wherein the first and second spaces are filled with a brake fluid; and    a brake pad attached to the at least one of the piston and the caliper body.    
   
   
       20 . A method of actuating a brake, the method comprising: 
 providing the apparatus of  claim 1;     rotating the shaft in a first direction so as to rotate the head about the axis and to move relative to the plug, whereby the second volume decreases, at least part of the fluid moves from the second space to the first space, and the piston moves relative to the caliper body.    
   
   
       21 . The method of  claim 20 , further comprising rotating the shaft in a second direction opposite to the first direction so as to rotate the head about the axis and move relative to the plug, whereby the second volume increases, at least part of the fluid moves from the first space to the second space, and the piston moves relative to the caliper body.