Dual relief valve of bsm for vehicle engine

Abstract

A dual relief valve apparatus of a Balance Shaft and Oil Pump Module (BSM) of a vehicle engine may include the pump housing, and a primary relief valve and a secondary relief valve mounted inside the pump housing, wherein the primary relief valve and the secondary relief valve may be sequentially opened or closed, wherein the primary relief valve may be first opened to release a first oil by a first oil discharge pressure applied thereto and sequentially the secondary relief valve may be opened to release a second oil by a second oil discharge pressure applied thereto, the first oil discharge pressure being relatively smaller than the second oil discharge pressure.

What is claimed is: 
     
         1 . A dual relief valve apparatus of a Balance Shaft and Oil Pump Module (BSM) of a vehicle engine, which is a valve mounted inside a pump housing to be opened/closed by pressure of oil discharged from the BSM, the dual relief valve apparatus comprising:
 the pump housing; and   a primary relief valve and a secondary relief valve mounted inside the pump housing, wherein the primary relief valve and the secondary relief valve are sequentially opened or closed,   wherein the primary relief valve is first opened to release a first oil by a first oil discharge pressure applied thereto and sequentially the secondary relief valve is opened to release a second oil by a second oil discharge pressure applied thereto, the first oil discharge pressure being relatively smaller than the second oil discharge pressure.   
     
     
         2 . The dual relief valve apparatus of  claim 1 , wherein the primary relief valve includes:
 a primary plunger slidably positioned inside a primary valve groove formed in the pump housing to operate therein; and   a primary elastic member disposed beneath the primary plunger inside the primary valve groove to elastically support the primary plunger.   
     
     
         3 . The dual relief valve apparatus of  claim 2 , further including:
 a first relief aperture formed in the pump housing and connected to the primary valve groove.   
     
     
         4 . The dual relief valve apparatus of  claim 3 , further including:
 an oil flow path through which the first oil is configured to pass is formed inside the primary plunger of the primary relief valve,   wherein the second oil flowed from a high pressure region in the pump housing through an upper portion of the primary plunger to the oil flow path is released through the first relief aperture via the oil flow path according to a movement of the primary plunger.   
     
     
         5 . The dual relief valve apparatus of  claim 4 , wherein the first oil is released through the first relief aperture in starting to move the primary relief valve in a middle-low speed region at the same time when movement of the primary relief valve is started in a low-speed region, and the opening of the primary relief valve is finished before opening of the secondary relief valve. 
     
     
         6 . The dual relief valve apparatus of  claim 3 , wherein the secondary relief valve includes:
 a secondary plunger positioned inside a secondary valve groove formed in the pump housing to operate therein; and   a secondary elastic member disposed beneath the secondary plunger inside the secondary valve groove to elastically support the secondary plunger.   
     
     
         7 . The dual relief valve apparatus of  claim 6 , further including:
 a second relief aperture formed in the pump housing and connected to the secondary valve groove.   
     
     
         8 . The dual relief valve apparatus of  claim 7 , wherein the first relief aperture is positioned higher than the second relief aperture. 
     
     
         9 . The dual relief valve apparatus of  claim 1 , wherein the secondary relief valve includes:
 a secondary plunger positioned inside a secondary valve groove formed in the pump housing to operate therein; and   a secondary elastic member disposed beneath the secondary plunger inside the secondary valve groove to elastically support the secondary plunger.   
     
     
         10 . The dual relief valve apparatus of  claim 9 , further including:
 a second relief aperture formed in the pump housing and connected to the secondary valve groove.   
     
     
         11 . The dual relief valve apparatus of  claim 10 , wherein the second oil in the secondary valve groove is released through the second relief aperture by starting to move the secondary relief valve in a high-speed region formed in the pump housing.