Variable capacity pump and working oil supply system for internal combustion engine

Abstract

Provided is a variable capacity pump where ease of control can be improved. A variable capacity pump includes a control chamber and a control valve. The control chamber is disposed between a pump accommodating chamber and a movable member, and the volume of the control chamber is variable with the movement of the movable member. Working oil discharged from a discharge portion is introduced into the control chamber. The control valve is provided in a passage and, with the movement of a valve element, the control valve varies the cross-sectional area of a flow passage, through which working oil in the control chamber is drained to a low pressure portion, while making the discharge portion and the control chamber communicate with each other.

1 . A variable capacity pump comprising:
 a housing including a pump accommodating chamber therein;   a pump structure disposed in the pump accommodating chamber, and configured to vary volumes of a plurality of working chambers with rotation, the pump structure being further configured to discharge from a discharge portion working oil introduced from an intake portion by being rotationally driven;   a movable member disposed in the pump accommodating chamber, and accommodating the pump structure to define the plurality of working chambers, the movable member being configured to cause an amount of increase or decrease in volume of each of the plurality of working chambers during rotation of the pump structure to be varied by moving so that an amount of eccentricity of a center of an inner periphery of the movable member from a center of rotation of the pump structure varies;   a first biasing member disposed in the pump accommodating chamber in a state where a set load is applied to the first biasing member, and configured to bias the movable member in a direction that the amount of increase or decrease in volume of each of the plurality of working chambers increases;   a first control chamber which is disposed between the pump accommodating chamber and the movable member, and into which the working oil discharged from the discharge portion is introduced, a volume of the first control chamber increasing with movement of the movable member in a direction opposing a biasing force of the first biasing member;   a second control chamber which is disposed between the pump accommodating chamber and the movable member, and into which the working oil discharged from the discharge portion is introduced through a passage, a volume of the second control chamber being variable with movement of the movable member; and   a control valve provided in the passage, and configured to vary, with movement of a valve element, a cross-sectional area of a flow passage, through which working oil in the second control chamber is drained to a low pressure portion, while making the discharge portion and the second control chamber communicate with each other.   
     
     
         2 . The variable capacity pump according to  claim 1 , wherein
 with movement of the valve element in a first direction, the control valve increases the cross-sectional area of the flow passage, through which working oil in the second control chamber is drained to the low pressure portion, while decreasing a cross-sectional area of a flow passage, through which working oil is introduced from the discharge portion to the second control chamber.   
     
     
         3 . The variable capacity pump according to  claim 1 , wherein
 with movement of the valve element in a second direction, the control valve decreases the cross-sectional area of the flow passage, through which working oil in the second control chamber is drained to the low pressure portion, while increasing a cross-sectional area of a flow passage through which working oil is introduced from the discharge portion to the second control chamber.   
     
     
         4 . The variable capacity pump according to  claim 1 , wherein
 the control valve is configured to continuously change a position of the valve element.   
     
     
         5 . The variable capacity pump according to  claim 4 , wherein
 the control valve is configured to stop the valve element at any position.   
     
     
         6 . The variable capacity pump according to  claim 1 , wherein
 the control valve includes a solenoid portion configured to generate an electromagnetic force for biasing the valve element.   
     
     
         7 . The variable capacity pump according to  claim 6 , wherein
 the solenoid portion is configured to move the valve element to any position according to a control signal.   
     
     
         8 . The variable capacity pump according to  claim 6 , wherein
 the valve element is integrally coupled to a plunger of the solenoid portion.   
     
     
         9 . The variable capacity pump according to  claim 1 , wherein
 the control valve includes a hollow member which accommodates the valve element, and which has a first port communicating with the discharge portion, a second port communicating with the second control chamber, and a third port communicating with a low pressure portion, openings of the first port, the second port, and the third port being formed on an inner periphery of the hollow member.   
     
     
         10 . The variable capacity pump according to  claim 9 , wherein
 the control valve includes a solenoid portion configured to generate an electromagnetic force for biasing the valve element, and   the valve element includes   a first land portion disposed on a first port side, and biased to one side by the solenoid portion,   a second land portion disposed on a third port side, and biased to an opposite side by a second biasing member, and   a connecting portion connecting the first land portion and the second land portion with each other.   
     
     
         11 . The variable capacity pump according to  claim 10 , wherein
 the second land portion varies an area of the opening of the third port as the first land portion varies an area of the opening of the first port.   
     
     
         12 . The variable capacity pump according to  claim 9 , wherein
 the control valve includes a solenoid portion configured to generate an electromagnetic force for biasing the valve element,   the opening of the second port is disposed between the opening of the first port and the opening of the third port,   the valve element includes a land portion biased to one side by the solenoid portion, and biased to the opposite side by a second biasing member, and   the land portion varies an area of the opening of the second port communicating with the opening of the first port, and an area of the opening of the second port communicating with the opening of the third port.   
     
     
         13 . The variable capacity pump according to  claim 1 , wherein
 a volume of the second control chamber increases with movement of the movable member in the same direction as a direction of a biasing force of the first biasing member.   
     
     
         14 . The variable capacity pump according to  claim 13 , wherein
 the movable member includes a first pressure receiving surface facing the first control chamber, and a second pressure receiving surface facing the second control chamber, and having a pressure receiving area larger than a pressure receiving area of the first pressure receiving surface.   
     
     
         15 . The variable capacity pump according to  claim 13 , wherein
 the movable member is configured to oscillate around a fulcrum in the pump accommodating chamber.   
     
     
         16 . The variable capacity pump according to  claim 13 , wherein
 the movable member is configured to perform a translational motion in the pump accommodating chamber.   
     
     
         17 . The variable capacity pump according to  claim 1 , wherein
 a volume of the second control chamber increases with movement of the movable member in a direction opposing the biasing force of the first biasing member.   
     
     
         18 . A variable capacity pump comprising:
 a housing including a pump accommodating chamber therein;   a pump structure disposed in the pump accommodating chamber, and configured to vary volumes of a plurality of working chambers with rotation, the pump structure being configured to discharge from a discharge portion working oil, which is introduced from an intake portion by being rotationally driven;   a movable member disposed in the pump accommodating chamber, and accommodating the pump structure to define the plurality of working chambers, the movable member being configured to cause an amount of increase or decrease in volume of each of the plurality of working chambers during rotation of the pump structure to be varied by moving so that an amount of eccentricity of a center of an inner periphery of the movable member from a center of rotation of the pump structure varies;   a first control chamber which is disposed between the pump accommodating chamber and the movable member, and into which working oil discharged from the discharge portion is introduced, a volume of the first control chamber increasing with movement of the movable member to one side,   a second control chamber which is disposed between the pump accommodating chamber and the movable member, and into which the working oil discharged from the discharge portion is to be introduced through a passage, a volume of the second control chamber being variable with movement of the movable member;   a cylindrical member having a hollow shape, and including a first port communicating with the discharge portion, a second port communicating with the second control chamber, and a third port communicating with a low pressure portion, openings of the first port, the second port, and the third port being formed on an inner periphery of the cylindrical member; and   a control valve including a spool movable in the cylindrical member, and a solenoid portion configured to move the spool, wherein   the spool includes a first large diameter portion configured to vary an area of the opening of the first port, and a second large diameter portion configured to vary an area of the opening of the third port, and   the first large diameter portion and the second large diameter portion are disposed on the inner periphery of the cylindrical member within a range sandwiched between the first large diameter portion and the second large diameter portion such that the first port, the second port, and the third port are allowed to be at least partially open simultaneously.   
     
     
         19 . A working oil supply system for an internal combustion engine, the working oil supply system comprising:
 a variable capacity pump which introduces working oil discharged from a pump structure into a control chamber disposed around a movable member, which accommodates the pump structure therein, so as to move the movable member to vary an amount of eccentricity of a center of the movable member from a center of rotation of the pump structure, thus varying a pressure of working oil discharged from the pump structure to the internal combustion engine;   a pressure measuring portion configured to measure a pressure of working oil discharged from the pump structure;   a rotational speed measuring portion configured to measure a rotational speed of the internal combustion engine; and   a control portion which calculates a pressure difference between a pressure measured by the pressure measuring portion and a pressure of working oil which the internal combustion engine is required to have at the rotational speed measured by the rotational speed measuring portion, the control portion varying, when the rotational speed is equal to or more than a predetermined rotational speed, and the pressure difference is larger than a predetermined pressure difference, a drainage amount of working oil from the control chamber to a low pressure portion while allowing working oil to be introduced into the control chamber until the pressure difference becomes equal to or less than the predetermined pressure difference.   
     
     
         20 . The working oil supply system for an internal combustion engine according to  claim 19 , wherein
 the control portion does not drain working oil from the control chamber to the low pressure portion when the rotational speed is less than the predetermined rotational speed.