Abstract: A pressure detection device for detecting an increase of pressure acting thereon includes an electrically conductive device housing which has an accommodation bore extending inward from one end of the device housing and a slide bare extending between the accommodation bore and the other end of the device housing. A piston is slidably disposed within the slide bore and adopted to receive a pressure, and a terminal serving as one electric contact is fixed to the accommodation bore via an electrical insulator. A disk spring serving as the other electric contact deforms due to a pressing force of the piston and coming in contact with the terminal. The pressure detection device further comprises an electro-functional member attached to either the terminal or the disk spring in which the electro-functional member is changeable its electric resistance due to an impressed pressing force acting thereon.

Abstract: A vane type rotary pump including a stator housing, a cam ring formed at its inner periphery with a cam surface and mounted within the stator housing, a pair of end wall structures fitted to the opposite ends of the cam ring to form a pump cavity in the cam ring, a drive shaft rotatably mounted within the stator housing and extending into the interior of the pump cavity through one of the end wall structures, a rotor contained within the cam ring and mounted on the drive shaft for rotation therewith, and a plurality of circumferentially equally spaced vanes slidably fitted into the body of the rotor to move radially outward from the rotor and cooperating with the cam surface of the cam ring to form a plurality of expandable pump chambers, wherein one of the end wall structures is formed at its inside face with a suction port at a portion where the pump chambers expand as the vanes move radially outward and is formed at its inside face with a discharge port at a portion where the pump chambers contract as the

Abstract: A hydraulic power steering apparatus includes a fluid pump, a power cylinder, a reservoir, and a control valve connected to the pump via a supply passage including a high pressure hose and connected to the reservoir via a drain passage. The power steering apparatus also includes a bypass passage provided between the supply passage and the drain passage, and a check valve which is disposed in the bypass passage to allow operation fluid to flow only in a direction from the drain passage to the supply passage. The power steering apparatus can supply a sufficient amount of operation fluid to the power cylinder even when a steering wheel is abruptly turned or when an opposing force is input from a tire.

Abstract: A hydraulic power steering apparatus includes a motor-driven pump which discharges pressurized working fluid at a flow rate proportional to the rotational speed. A load-pressure responsive valve is connected to a discharge passage to which the pressurized fluid is discharged from the pump. The load-pressure responsive valve bypasses the pressurized fluid to a reservoir when the control valve is in a neutral state, thereby reducing the amount of the pressurized fluid supplied to the control valve, and increases the amount of the pressurized fluid supplied to the control valve when the load pressure of the pump increases upon operation of the control valve. With this control, the energy consumed by the pump can be reduced.

Abstract: A power steering apparatus is composed a fluid source for discharging pressurized fluid, a power cylinder, a control valve responsive to operation of a steering wheel for supplying the power cylinder with pressurized fluid from the fluid source, and a reservoir. The control valve has a first control portion for controlling the flow of pressurized fluid from the fluid source to the reservoir, and a second control portion for controlling the flow of pressurized fluid to the power cylinder. The first control portion has four paths communicating with the fluid source and the reservoir, and each of the four paths is formed with a center-open variable orifice which opens when the control valve is in a neutral state.

Abstract: A hydraulic power steering system includes a pump, a flow control valve, and a bypass control valve. The flow control valve responds to a pressure drop across a metering orifice disposed in a fluid supply passage so as to control the flow rate of operating fluid by bypassing a part of the operating fluid to a reservoir. A spring chamber of the flow control valve is connected to the supply passage through a control orifice. The bypass control valve is disposed between the spring chamber and the reservoir so as to increase the amount of bypassed fluid by controlling the pressure in the spring chamber. The bypass control valve has a control spool, a load pressure introduction port connected to the upstream side of the control orifice for leading the load pressure to a first end of the control spool and a pilot port connected to the downstream side of the control orifice for leading the pressure in the spring chamber of the flow control valve to a second end of the control spool.

Abstract: A power steering apparatus comprises a fluid source for supplying pressurized fluid, a power cylinder having a pair of fluid chambers, a control valve, and a drain control mechanism. The control valve is composed of first and second control portions. The first control portion has four paths connecting the fluid source and the reservoir, and each of the four paths is formed with a variable orifice of center-open type. The second control portion has two supply paths communicating the fluid source with the fluid chambers of the power cylinder, each of the supply paths being formed with a variable orifice of center-open type, and two drain paths communicating the fluid chambers with the reservoir, each of the drain paths being formed with a variable orifice of center-closed type.

Abstract: A power steering apparatus having a fluid source for discharging pressurized fluid, a power cylinder, a control valve responsive to operation of a steering wheel for supplying the power cylinder with pressurized fluid from the fluid source, and a reservoir. The control valve has a first control portion for controlling the flow of pressurized fluid from the fluid source to the reservoir, and a second control portion for controlling the flow of pressurized fluid to the power cylinder. The first control portion has two paths connecting the fluid source and the reservoir, each of the paths being formed with at least one variable orifice of a center-open type which opens when the control valve is in a neutral state.

Abstract: A hydraulic power steering system includes a pump, a flow control valve, and a bypass control valve. The flow control valve responds to a pressure drop across a metering orifice disposed in a fluid supply passage so as to control the flow rate of operational fluid by bypassing part of the operational fluid to a reservoir. A spring chamber of the flow control valve is connected to the supply passage through a control orifice. The bypass control valve is disposed between the spring chamber and the reservoir so as to increase the amount of bypassed fluid by controlling the pressure in the spring chamber. The bypass control valve has a control spool, a load pressure introduction port connected to the upstream side of the control orifice for leading the load pressure to a first end of the control spool and a pilot port connected to the downstream side of the control orifice for leading the pressure in the spring chamber of the flow control valve to a second end of the control spool.

Abstract: A power steering apparatus having a hydraulic pump for outputting a pressurized fluid, an assist force generation mechanism hydraulically connected to the pump through a supply passage to generate an assist force in response to rotation of a steering wheel, wherein the assist force generation mechanism has a characteristic that the back pressure thereof increases when the steering wheel is rotated. The power steering apparatus further comprises a flow control valve having a spool which is moved in response to a pressure drop at a metering orifice disposed in the middle of the supply passage, so as to control the flow rate of the pressurized fluid to be constant.

Abstract: A power steering apparatus for turning a steerable wheel of a vehicle in response to steering operation by a driver. The apparatus comprises a hydraulic pump for pumping a fluid from a reservoir so as to supply pressurized fluid to a power cylinder formed in a gear housing through a direction control valve which is operable in response to rotation of the steering wheel for selectively delivering the pressurized fluid to pair of pressure chambers of the power cylinder. The apparatus further comprises an electric motor for rotating the hydraulic pump, an accumulator for accumulating the pressurized fluid discharged from the hydraulic pump, a detector for detecting the pressure of the pressurized fluid and for outputting a signal corresponding to the detected pressure, and a controller responsible to the signal from the detector for activating the electric motor only when the detected pressure is below a predetermined level. The hydraulic pump and the electric motor are mounted on the gear housing.

Abstract: A rotary shock absorber suitable for use in a suspension system of a vehicle. The shock absorber is provided with a housing and a rotary shaft supported by the housing for relative rotation thereto. A pressure chamber is formed in the housing and a rotor having a pair of blades is received within the pressure chamber. Further, a pair of partition walls are formed within the pressure chamber to define first and second chambers at both sides of each blade, and the first and second chambers are communicated with each other through throttles. When the rotary shaft is rotated, a high viscous fluid filled within the first and second chambers flows therebetween through the throttles. Due to the flow resistances of the throttles, pressures are generated in the first or second chambers. This pressure generation is used to generate a damping force.

Abstract: A rotary coupling for torque transmission is arranged between two relatively rotatable shafts to transmit a rotational torque in response to a rotational speed difference therebetween. The device includes a housing connected to the first shaft for rotation therewith, a clutch means for transmitting rotational torque between two shafts, and a piston which thrusts the clutch means in the axial direction. The rotary coupling also includes a rotor received in a cylindrical space, in which a high viscous fluid is filled to be compulsorily moved by the rotor. Each side surface of the rotor is provided with plural depressions at regular interval in the circumferential direction. The depressions have inclining surfaces inclining in the rotational direction of the rotor. When a rotational speed difference occurs between the two shafts, wedge effects occur between the inclined surfaces and the housing and between the inclined surface and the piston so that a high pressure is generated in the space section quickly.

Abstract: A driving power transmission system for transmitting a driving power to front tires and rear tires, wherein a torque transmission device is disposed within a drive line for controlling transmissive torque transmitted to the tires. The torque transmission device is provided with a rotational housing to which a driving power from an engine is applied, a cylindrical shaft which is drivingly connected to the tires. The housing receives a clutch mechanism for transmitting a rotational torque from the housing to the cylindrical shaft, a piston located adjacent to the clutch mechanism and a pressure generating mechanism having an input rotational shaft for generating a pressure so as to actuate the clutch mechanism through the piston.

Abstract: In a vane pump, a pump housing assembly contains a cam ring having an internal cam surface. A rotor carrying plural vanes is disposed within the cam ring and rotated by a drive shaft. Both end surfaces of the cam ring contact with a pair of flat contact surfaces formed within the pump housing assembly, respectively, and the vanes define plural pump sectors between the rotor and the cam ring, together with the rotor, the cam ring and the pair of contact surfaces. The contact surfaces are formed with a pair of intake ports and a pair of exhaust ports. Furthermore, one of the contact surfaces is provided with a pair of pressure leaking grooves formed at locations between the intake ports and the exhaust ports.

Abstract: A driving power transmission device having a clutch provided between a first shaft and a second shaft relatively rotatable to each other for transmitting a driving power is provided, wherein a housing to which the first shaft is connected and a piston provided in the housing for actuating the clutch define a cylindrical space in order to receive a plurality of blades rotatable with the second shaft. High viscous fluid is filled within the cylindrical space defined by the housing and the piston. Each of the blades has a convexly curved side surface and a concavely curved side surface located at opposite sides in rotational direction. When the first shaft rotates faster than the second shaft, the convexly curved side surfaces of the blades compulsorily displaces the high viscous fluid within the space in order to generate a pressure actuating the clutch through the piston. In this forward torque transmission, the tranmissive torque becomes relatively large.

Abstract: In a vane pump, a pump housing contains a cam ring having an internal cam surface, in which a rotor carrying eight vanes is rotatable by a drive shaft. A pair of side plates positioned in the receiving bore in contact engagement with the opposite end surface of the cam ring, the internal cam surface and the rotor define a pump chamber. Each of the side plates is formed at its inside surface contacting the cam ring with a pair of intake ports, a pair of exhaust ports and a vane back pressure groove. This groove is always filled with pressurized fluid supplied from the exhaust ports such that the pressurized fluid is directed into vane support slits formed in the rotor.

Abstract: A rotary servovalve includes a valve sleeve and a rotor relatively rotatably fitted therein, and includes a pressure control section composed of lands angularly spaced from each other when the servovalve is in a neutral condition and a pressure characteristic adjusting section composed of lands disposed in overlapping relation to each other when the servovalve is in the neutral condition. The lands of the pressure control section have first chamfers for gradually reducing the area of communication between fluid supply and discharge passages as the valve sleeve and the rotor are relatively turned, and the lands of the pressure characteristic adjusting section have second and third chamfers for gradually increasing and then gradually reducing the area of communication between the fluid supply and discharge passages as the valve sleeve and the rotor are relatively turned.

Abstract: A rotary servovalve for a power steering system is provided wherein a plurality of orifices are established by a plurality of axial extending lands formed on the internal surface of a valve sleeve and the circumferential surface of a rotor received therein. As the rotor rotates relative to the sleeves, the orifices control the pressure and the flow of fluid supplied from a pump to a power cylinder of the steering system and from the power cylinder to a reservoir. Each of the lands on the rotor is formed at each of its circumferential edges with a chamfer which has a third slope for preventing the generation of cavitation and hissing noise, in addition to first and second slopes for offering an optimum steering feeling to a vehicular driver.

Abstract: A rotary valve for a power steering system includes a valve sleeve in which a rotor is rotatably carried for controlling fluid flow from a supply pump to a cylinder of the power steering system. A plurality of lands are formed on the outer periphery of the rotor, at least three of which have the same configuration. A plurality of lands are formed on the inner periphery of the valve sleeve, at least two of which have the same configuration to thereby vary the areas of two orifices formed between the three lands of the rotor and the two lands of the valve sleeve at the same rate during relative rotation therebetween. Further, the edge portions of the three lands of the rotor are formed with two longitudinally curved slopes so as to provide an optimum two-step valving characteristic.