Pulsation pressure decreased type pump for vehicle slip control system

Abstract

The present invention provides a pulsation pressure decreased type pump. When an oil pump that is driven by a motor during the operation of an electronically controlled brake system discharges a working fluid, the working fluid passes through an annular orifice provided at a position where the working fluid is discharged and is then discharged to an outlet of a pump housing through an outflow channel formed in the orifice so as to decrease a pulsating pressure using a piston reciprocated by a cam. Therefore, it is possible to decrease a pulsating pressure generated in the pump from 20 bar to 5 bar or less.

1 . A pulsation pressure decreased type pump for a vehicle slip control system, comprising:
 a hollow sleeve that is fixed to a pump housing, receives a working fluid through an inflow channel formed in a radial direction, and includes a channel formed inside an end thereof opposite to the inflow channel;   a piston that is elastically supported in the sleeve by an inner spring and is reciprocated by the drive of the pump so as to allow the working fluid to flow into an inflow channel communicating with the inflow channel of the sleeve;   an inlet check valve including a ball that blocks an outlet through which the working fluid flowing into the piston passes, a check valve spring that is fixed to an outlet of the piston and elastically supports the ball, and a cover that receives the check valve spring, is fixed to the piston, and has a radial channel serving as an outlet for the working fluid;   an outlet check valve including a ball that is received in a cap fixed to an end of the sleeve and opens or closes a passage of the working fluid discharged from the sleeve, and a check valve spring that is inserted into the cap so as to elastically support the ball; and   an orifice that is provided between the sleeve and the cap fixed to the end of the sleeve and changes the flow of the working fluid discharged from the sleeve so as to decrease a pulsating pressure of the working fluid caused by the reciprocation of the piston, an outflow channel being integrally formed with the orifice so that the working fluid discharged from the sleeve through the outlet check valve is guided to an outlet of the pump housing.   
   
   
       2 . The pulsation pressure decreased type pump as defined in  claim 1 , wherein the orifice includes:
 an annular body that has a central hole, with which the ball of the outlet check valve comes in close contact, at the center thereof;   fixation ends that protrude from the annular body and are fitted to a stepped orifice fixing end formed at the end of the sleeve; and   an outflow channel that guides the working fluid, which is discharged from the sleeve through the annular body, to the outlet of the pump housing.   
   
   
       3 . The pulsation pressure decreased type pump as defined in  claim 2 , wherein a plurality of fixation ends is provided to the orifice in order to increase a fixation force between the end of the sleeve and the fixation ends. 
   
   
       4 . The pulsation pressure decreased type pump as defined in  claim 3 , wherein the fixation ends are formed in the annular body at three positions where the annular body is divided at an interval of 120°, so as to apply a reliable fixation force to the orifice fixing end of the sleeve. 
   
   
       5 . The pulsation pressure decreased type pump as defined in  claim 3 , wherein the fixation ends include an upper fixation end that is bent to protrude toward one side of the annular body, and a pair of left and right lower fixation ends that is bent to protrude toward one side of the annular body at positions corresponding to an angle of about 120° from the upper fixation end. 
   
   
       6 . The pulsation pressure decreased type pump as defined in  claim 5 , wherein left and right divided fixation ends, which are separated from each other and face each other, are formed by cutting a central portion of the upper fixation end so that an outflow channel for guiding the working fluid discharged from the sleeve to the outlet of the pump housing is formed in the upper fixation end. 
   
   
       7 . The pulsation pressure decreased type pump as defined in  claim 2 , wherein the outflow channel includes:
 an inlet that is formed by cutting the annular body so as to allow the working fluid to flow;   a narrow portion that communicates with the inlet and decreases a flow width of the working fluid to increase the flow speed of the working fluid;   an extension portion that forms an end of the narrow portion and has a narrow width; and   a wide portion that expands at the end of the extension portion.   
   
   
       8 . The pulsation pressure decreased type pump as defined in  claim 2 , wherein the orifice is integrally formed by pressing.