Variable displacement pump

Patent metadata

Field	Value
Publication number	US-10677245-B2
Application number	US-201615547958-A
Country	US
Kind code	B2
Filing date	Jan 27, 2016
Priority date	Feb 6, 2015
Publication date	Jun 9, 2020
Grant date	Jun 9, 2020

Abstract

A variable displacement pump includes: a pump constituting section; a movable member; a first control hydraulic chamber; a second control hydraulic chamber; a control mechanism arranged to be actuated by receiving a control hydraulic pressure which is the discharge pressure on a downstream side of the discharge portion, through a single control passage formed within the engine, and to control a supply and a discharge of the discharge pressure with respect to the second control hydraulic chamber; and a switching mechanism arranged to switch a connection and a disconnection between the control passage and the control mechanism.

First claim

The invention claimed is:

1. A variable displacement pump arranged to supply oil to a main oil gallery through an oil filter provided in a cylinder block, the variable displacement pump comprising:
a pump body including a pump receiving chamber formed therein;
a pump constituting section received in the pump receiving chamber, arranged to be driven and rotated by an internal combustion engine, and structured to vary volumes of a plurality of pump chambers, and thereby discharge oil sucked from a suction portion through a discharge portion and the oil filter to the mail oil gallery;
a movable member within which the pump constituting section is received, and which is arranged to be moved to vary variation amounts of the volumes of the pump chambers;
an urging mechanism provided with a set load, and arranged to urge the movable member in a direction in which the variation amounts of the volumes of the plurality of the pump chambers are increased;
a supply passage formed within the pump body, and bifurcated in the pump body from a passage between the discharge portion and the oil filter;
a first control hydraulic chamber formed between the moveable member and a circumferential wall of the pump body forming the pump receiving chamber, and arranged to receive the oil discharged from the discharge portion through the supply passage, and thereby act a force to the movable member in a direction in which the variation amounts of the volumes of the plurality of the pump chambers are decreased;
a second control hydraulic chamber formed between the moveable member and the circumferential wall of the pump body forming the pump receiving chamber, and arranged to receive the oil discharged from the discharge portion through the supply passage into the second control hydraulic chamber, and thereby act a force to the movable member in a direction in which the variation amounts of the volumes of the plurality of the pump chambers are increased;
a switching mechanism connected to a control passage bifurcated from the main oil gallery, and arranged to be controlled by a control unit; and
a control mechanism connected to the switching mechanism, and arranged to switch a first state in which the second control hydraulic chamber is connected to atmosphere, and a second state in which the second control hydraulic chamber and the supply passage are connected, in accordance with a hydraulic pressure of oil introduced through the switching mechanism.

2. The variable displacement pump as claimed in claim 1 , wherein the control mechanism is arranged to supply the discharge pressure from the discharge portion to the second control hydraulic chamber, or to discharge a hydraulic fluid within the second control hydraulic chamber; and when the control mechanism supplies the discharge pressure from the discharge portion to the second control hydraulic chamber at a speed of the pump that is higher than a predetermined speed, the control mechanism discharges the hydraulic fluid of the second control hydraulic chamber in accordance with an increase of the discharge pressure so as to decrease and adjust the pressure within the second control hydraulic chamber.

3. The variable displacement pump as claimed in claim 2 , wherein the control mechanism includes
an introduction port arranged to introduce a control hydraulic pressure from the control passage, and a valve body including a discharge side connection port connected to the second control hydraulic chamber, and a drain port connected to a low pressure portion,
a spool valve received within the valve body to be slideable in an axial direction of the valve body, and arranged to switch a connection and a disconnection of the discharge side connection port and the drain port with respect to the second control hydraulic chamber in accordance with an axial sliding position, and
a control spring elastically mounted within the valve body, and arranged to urge the spool valve on one axial side of the valve body by an urging force smaller than an urging force of the urging mechanism.

4. The variable displacement pump as claimed in claim 3 , wherein the variable displacement pump is configured to attain
the first state in which the drain port and the second control hydraulic chamber are connected, at a first position at which the spool valve is maximally moved relative to the one axial side of the valve body by being urged by the control spring;
the second state in which the discharge side connection port and the second control hydraulic chamber are connected, and in which the drain port and the second control hydraulic chamber are disconnected, at a second position at which the spool valve is moved relative to another axial side of the valve body against the spring force of the control spring by the control hydraulic pressure supplied to the introduction port in accordance with the increase of the discharge pressure; and
a third state in which the discharge side connection port and the second control hydraulic chamber are connected, and in which the drain port and the second control hydraulic chamber are connected, at a third position to which the spool valve is further moved relative to the another axial side of the valve body by the control hydraulic pressure by the further increase of the discharge pressure.

5. The variable displacement pump as claimed in claim 4 , wherein the spool valve includes land portions which are positioned at both axial end portions of the spool valve, and at a middle position between the both axial end portions, and which are arranged to be slideable on the valve body, and small diameter shaft portions formed, respectively, between the land portions; and the spool valve is arranged to connect the discharge side connection port and the drain port to the second control hydraulic chamber by outer circumferences of the small diameter shaft portions, and to disconnect the discharge side connection port and the drain port from the second control hydraulic chamber by the land portions.

6. The variable displacement pump as claimed in claim 5 , wherein the introduction port is provided at the one axial end of the valve body; and the spool valve includes a pressure receiving surface formed at one axial end portion of the spool valve on an introduction port side, and arranged to receive the control hydraulic pressure supplied from the control passage.

7. The variable displacement pump as claimed in claim 6 , wherein the discharge side connection port and the drain port are provided in a circumferential wall of the valve body in radial directions.

8. The variable displacement pump as claimed in claim 1 , wherein the control mechanism includes a first control portion and a second control portion;
the first control portion is arranged to supply the discharge pressure from the discharge portion to the second control hydraulic chamber, or to discharge hydraulic fluid within the second control hydraulic chamber;
the second control portion is arranged to discharge the hydraulic fluid within the second control hydraulic chamber through a drain passage, or to disconnect the second control hydraulic chamber and the drain passage; and
when the first control portion supplies the discharge pressure from the discharge portion to the second control hydraulic chamber at a speed of the pump that is higher than a predetermined speed, the second control portion is arranged to discharge the hydraulic fluid within the second control hydraulic chamber in accordance with an increase of the discharge pressure, and thereby decrease and adjust the pressure within the second control hydraulic chamber.

9. The variable displacement pump as claimed in claim 8 , wherein
the first control portion includes
a first valve body including a

Assignees

• Hitachi Automotive Systems Ltd

Inventors

• Naganuma Atsushi

Classifications

• F01M1/08

  Lubricating systems characterised by the provision therein of lubricant jetting means · CPC title

• F01M1/16 Primary

  Controlling lubricant pressure or quantity (rendering machines or engines inoperative or idling on lubricant pressure failure F01M1/22) · CPC title

• F04C14/223 Primary

  using a movable cam · CPC title

• F01M1/02

  using lubricating pumps (pumps in general F04; lubricating pumps per se F16N) · CPC title

• F04C15/008

  Prime movers · CPC title