Unisia Jecs Corporation

Hitachi, Ltd.

Hitachi Automotive Systems Steering, Ltd.

Hitachi Astemo Ltd.

Yukio Uchida

Norihiro Saita

Jun Soeda

Satoshi Muramatsu

Norikatsu Hoshina

Tatsuyoshi Maruyama

Tadaharu Yokota

Toshinori Aihara

Michiya Hiramoto

Miyoko Hamao

Atsushi Ishizuka

Kazuyoshi Ishizaki

Mizuo Ohtaki

Masateru Yamamuro

Masaaki Iijima

Sachiko Nojyo

Tomohiko Nakazono

Norikazu Kumasaka

Hiroki Imanaga

Takao Muto

Tetsuya Ishii

A pump device includes: a drive shaft; a pump element; a pump housing including; a pump element receiving space, first and second bearing receiving spaces, a suction passage, a discharge passage, a return passage, and a seal receiving space, a first bearing including a first lubrication groove, received within the first bearing receiving space, and supporting the drive shaft; a second bearing which includes a second lubrication groove having a sectional area that is perpendicular to the rotation axis, and that is greater than a sectional area of the first bearing that is perpendicular to the rotation axis, which is received within the second bearing receiving space, and which supports the drive shaft; and a seal member provided within the seal receiving space, and arranged to seal between the drive shaft and the pump housing.

Pump device

A variable displacement vane pump is provided. This pump includes a pump housing including, a driving shaft, a rotor, a plurality of vanes, a cam support surface, a cam ring, an intake port formed at the pump housing, a discharge port formed at the pump housing, and a cam ring control mechanism disposed at the pump housing and configured to control an eccentric amount of the cam ring with respect to the rotor. The cam support surface is formed in such a manner that a shortest distance between the cam support surface and a reference line decreases from a second confining region side toward a first confining region side, and the cam ring is formed in such a manner that a cam profile radius change rate decreases first and then increases again on the second confining region side when eccentric amount of the cam ring is maximized.

Variable displacement vane pump

A variable displacement vane pump and a power steering can secure a discharge flow rate when a steering wheel is turned, and restrict the discharge flow rate when the steering wheel is not turned. In the variable displacement vane pump and power steering system, a bypass line is formed. The bypass line causes a hydraulic fluid in a high pressure chamber of a control valve, which controls an eccentricity of a cam ring, to flow directly to a low pressure chamber side of the control valve. The hydraulic fluid flows directly to the low pressure chamber side of the control valve when the steering wheel is turned.

Variable displacement vane pump and power steering system

A variable displacement pump includes: a pump body; a rotor; a cam ring; inlet and outlet ports; first and second fluid pressure chambers; a metering orifice provided in a discharge passage connected with the outlet port; a pressure regulating section arranged to regulate the pressure introduced into the first or second fluid pressure chamber, and including a high pressure chamber, a middle pressure chamber, and a low pressure chamber; a relief valve; a pilot orifice provided in a passage connecting the metering orifice and the middle pressure chamber, and having a circular section with a diameter of a mm; and a damper orifice provided in a passage connecting the outlet port and the high pressure chamber, and having a circular section with a diameter of b mm. The pilot orifice and the damper orifice satisfy the following relationships: a+2b&#x2212;2.1&#x2267;0, &#x2212;4a+b&#x2212;16.3&#x2266;0, and a&#x2266;1.8.

Variable displacement pump

A variable displacement vane pump that assuredly suppresses seizing of mutually contacting surfaces of a pressure plate and a rotor where the pressure plate is formed, at one side surface thereof that slidably contacts the rotor, with an annular lubricating groove. The lubricating groove is on a seal surface of the side surface at a position between arcuate back pressure grooves formed on the seal surface and a through opening which is formed in a center part of the pressure plate to receive the drive shaft. A radial width of the lubricating groove is set to a range from 10% to 25% of a radial width of the seal surface, and a distance from a center of the radial width of the lubricating groove to an inner cylindrical surface of the through opening is set to a range from 24% to 70% of the radial width of the seal surface.

A variable displacement vane pump includes a rotor, a cam ring; and a pump casing including first and second side walls disposed on both sides of the cam ring, and a circumferential wall surrounding the cam ring and defining first and second pressure chambers. A pressure introduction groove is formed in a sliding contact surface between the cam ring and one of the first and second side walls, and arranged so that a pressure lower than an outlet pressure is introduced.

A vane pump comprising a pump housing, including an inlet, an outlet, and therein a hollow space, a cam ring received in the hollow space, a rotor placed in the cam ring and defining a rotation axis. The rotor comprises plural vanes arranged in corresponding slots formed in the rotor with a slidable contact in a radial direction of the rotor. A first wall member is received in the hollow space, one side of the first wall member faces one side of the cam ring, and the first wall member comprises an intake passage provided with a groove that is formed so that a partition wall portion is defined between the intake passage and an interface between the first wall member and the cam ring. A pair of intake ports are formed on the one side of the first wall member, each intake port is connected with the inlet by the intake passage, and a pair of outlet ports are formed on the one side of the first wall member.

Vane pump having an intake groove through a side wall member

A hydraulic pump including a pressure chamber, a drain passage communicable with the pressure chamber, a delivery port, a discharge path fluidly connecting the pressure chamber with the delivery port, and an orifice disposed in the discharge path. A first flow control valve is provided for variably controlling fluid communication between the pressure chamber and the drain passage in response to a difference between fluid pressures upstream and downstream of the orifice. A second flow control valve is disposed within the discharge path, which is operative to variably control an opening area of the orifice in response to energy of fluid passing through the discharge path. The second flow control valve includes a moveable spool exposed to a fluid pressure within the pressure chamber, a spring biasing the spool in such one direction as to increase the opening area of the orifice, and a spring retainer cooperating with the spool to define a spring chamber accommodating the spring.

Hydraulic pump for power steering system

A power assisted steering apparatus for a vehicle having a driving source, such as an engine, has an actuator, a hydraulic pump, a working oil pressure passage, and a drive switch. The actuator, which is in the vehicle steering mechanism, receives a supply or exhaust of a working oil to assist the steering operation. The pump is selectively driven by an engine via a clutch mechanism. The working oil discharged from the pump is introduced into the actuator via the passage. The check valve is interposed within the passage to enable flow in one direction away from the pump. The drive switch structure is disposed within the passage, downstream from the check valve. With this arrangement, the drive switch structure can be activated by pressure in the passage downstream of the check valve to control the clutch mechanism.

Power assisted steering apparatus for automotive vehicle

A flow control device or valve used in a power steering system of an automotive vehicle. The flow control device comprises a housing formed with an axially extending hole in which a spool valve is movably disposed. A first pressure chamber is defined in the hole, with one end of the spool valve. A drain passage is opened to the first pressure chamber and closable with the spool valve. A second pressure chamber is defined in the hole, with the other end of the spool valve. A restricting orifice is provided to be communicated with the first pressure chamber. An introduction passage is formed to be communicated through the restricting orifice with a discharge passage and opened to the first pressure chamber. The pressure in the discharge passage is introduced to the second pressure chamber. A first spring is disposed in the second pressure chamber to bias the spool valve in a direction to close the drain passage. A spring holding member is movably and coaxially disposed in the axially extending hole. The spring holding member has a first end face defining the second pressure chamber, and a second end face which is larger in pressure-receiving area than the first end face. The first spring is disposed between the spool valve and the first end face of the spring holding member. The second end face of the spring holding member defines a pressure control chamber communicated with the second pressure chamber. Additionally, a second spring is provided to bias the spring holding member in a direction to reduce a volume of the pressure control chamber.

Flow control device

In a power steering system which has a fluid pump and a hydraulic actuator, there is used a flow control device which comprises a spool unit slidably received in a spool receiving bore in a manner to partition the bore into first and second pressure chambers. The spool unit comprises a hollow cylindrical outer spool slidably received in the spool receiving bore. The outer spool has a bottom portion exposed to the second pressure chamber. The bottom portion has an aperture formed therethrough. A cylindrical inner spool is incorporated with the outer spool. The inner spool includes a larger diameter portion slidably received in a major part of the outer spool and a smaller diameter portion slidably received in the aperture of the bottom portion of the outer spool. The inner spool is engaged with a control spring to be biased toward the first pressure chamber. A spring member is employed for biasing the outer and inner spools toward the second and first pressure chambers respectively.

Flow control device of power steering system

A fluid-flow control valve device comprises a control orifice being fluidly disposed upstream of the outlet passage for variably restricting a flow of working fluid from the inlet passage to the outlet passage, a valve spool slidably accommodated in the spool chamber and defining first and second pressure chambers, and a control spring disposed in the second pressure chamber for biasing the valve spool toward the first pressure chamber, and a spring-bias adjustment device for variably adjusting a set spring-bias of the control spring associated the valve spool in response to a change in the pressure in the outlet passage.

Fluid-flow control valve

In a flow control valve, a valve spool is movable for variably controlling an opening area of a port portion of a drain passage so that a necessary flow rate of fluid is conducted from a first pressure chamber to an outlet passage through a control orifice while a surplus flow rate of fluid is returned from the first pressure chamber to the drain passage. A movable sleeve is installed in a valve spool accommodation hole and around the valve spool. The movable sleeve has through holes communicable with the drain passage and an inlet passage, respectively. The movable sleeve has a first axial end portion disposed in the first pressure chamber and a second axial end portion disposed in a low pressure chamber. A spring is disposed in the low pressure chamber for urging the movable sleeve toward the first pressure chamber side. The movable sleeve is movable relative to the valve spool in response to a variation of pressure in the first pressure chamber for varying the opening area of the port portion of the drain passage.

Growing community of inventors

Atsugi, Japan

Yukio Uchida