Toyoda Koki Kabushiki Kaisha

Toyota Jidosha Kabushiki Kaisha

Toyota Jidosha Kogyo Kabushiki Kaisha

Kyosuke Haga

Mikio Suzuki

Yoshiharu Inaguma

Hideya Kato

Kenichi Fukumura

Tsuneo Tanaka

Katsuhisa Mori

Hiroaki Asano

Toshifumi Sakai

Jiro Nakano

Keiji Suzuki

Yutaka Mori

Kunihiko Eto

Motoyasu Yamamori

Keiichi Nakamura

Nobuo Kamiya

Hidetoshi Fujiwara

Tomonari Yamakawa

Katsunori Yamada

Tetsuro Yamakage

Yoshiyuki Takeuchi

Mitsuru Asai

Naoyuki Kokubo

Satoshi Ashida

Kiyotaka Kato

Satoshi Suto

Kengo Yoshioka

Ryutaro Abe

Seiho Kawakami

Yoshio Shima

Isao Ito

Yukihiro Tanigawa

Masanori Natsume

Kaname Saito

Yoshikazu Sano

Tomomi Nakayama

Hironori Hibino

Sadamu Tuge

Youzo Yamaguchi

Masaharu Ooba

Miko Suzuki

Shookichi Shiozawa

Tatsuya Yamamoto

Makoto Kawahara

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. Further, at least one of a notch and a chamfer is provided on the electro-functional member for changing its electric resistance characteristic.

Pressure detection device

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 vanes move radially inward and a bearded groove tapered from a forward end of the discharge port in a direction opposite to a rotational direction of the rotor; the vane type rotary pump being characterized in that the bearded groove is formed with an introducing portion the surface of which is inclined into the interior of the discharge port.

Vane type rotary pump having a discharge port with a tapered bearded

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.

Hydraulic power steering apparatus

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.

Power steering apparatus

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. The second control portion has two supply paths communicating with the fluid source and a pair of chambers of the power cylinder, each of the two supply paths is formed with a semi-center-open variable orifice which opens when the control valve is in the neutral state, and two drain paths communicating with the chambers of the power cylinder and the reservoir, each of the two drain paths is formed with a center-closed variable orifice of which closes when the control valve is in the neutral state.

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. Moreover, a pressure receiving area of the second end of the control spool is smaller than that of the first end of the control spool. Accordingly, a spring having a small spring constant can be used in the bypass control valve, even when the control spool is controlled within a short stroke. Further, the control spool, the load pressure introduction port, and the pilot port are formed in a sleeve.

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. The drain control mechanism is responsive to differential pressure between the fluid chambers of the power cylinder to control the communication of one fluid chamber under high pressure with the reservoir, and is responsive to a vehicle speed to control the communication of both fluid chambers with the reservoir.

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. The second control portion has two supply paths communicating with the fluid source and a pair of chambers of the power cylinder, each of the supply paths being formed with a variable orifice of a center-close type which closes when the control valve is in the neutral state, and two drain paths communicating with the pair of chambers and the reservoir, each of the drain paths being formed with a variable orifice of a center-open type which opens when the control valve is in the neutral state.

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. Moreover, a pressure receiving area of the second end of the control spool is smaller than that of the first end of the control spool. Accordingly, a spring having a small spring constant can be used in the bypass control valve, even when the control spool is controlled within a short stroke.

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. The spring chamber of the flow control valve is connected to a reservoir through a drain passage, and a drain valve is disposed in the drain passage for allowing the flow of pressurized fluid from the spring chamber to the reservoir when the back pressure of the assist force generation mechanism is low, and for prohibiting the flow of the pressurized fluid when the back pressure of the assist force generation mechanism increases.

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.

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. The shock absorber is further provided with a mechanism which changes the characteristic of damping force generation depending on the rotational direction of the rotary shaft. In some embodiments, the shock absorber has a stopper function which drastically increases the damping force at the stroke ends.

Rotary shock absorber having vanes with radial flow clearance

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.

Rotary coupling for torque transmission

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. The torque transmission device further provided with a differential speed amplifying mechanism connected to the housing and the cylindrical shaft for amplyifying a rotational speed difference therebetween in order to rotate the input rotational shaft of the pressure generating mechanism at an amplified speed. When the rotational speed difference occurs between the housing and the cylindrical shaft, the speed difference is amplified by the amplifying mechanism and then applied to the pressure generating mechanism. As a result, a large pressure is quickly generated and is applied to the clutch mechanism via the piston in order to actuate the clutch mechanism.

Driving power transmission system for vehicle

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. The locations of the pressure leaking grooves are chosen so as to leak fluid in pump sectors communicating with the exhaust ports to adjacent pump sectors communicating with the intake ports through passages formed by the pressure leaking grooves and the side edges of vanes located between the two pump sectors whenever the instantaneous pressure of the fluid in the exhaust ports approaches an instantaneous maximum pressure. With this operation, the instantaneous maximum pressure is decreased, thereby the amplitude of the pressure pulsation being reduced.

Growing community of inventors

Anjo, Japan

Kyosuke Haga