Toyoda Koki Kabushiki Kaisha

Toyota Jidosha Kogyo Kabushiki Kaisha

Toyoda Koki Kabushiki K.

Minoru Kawabata

Mikio Suzuki

Kenji Takahashi

Yoshiharu Inaguma

Susumu Honaga

Yukio Kondo

Yutaka Mori

Akio Numazawa

Ryutaro Abe

Tohru Toshioka

Toshimaso Miyata

A solenoid-operated valve particularly for use in a speed-responsive power steering system on a motor vehicle comprises a valve housing having two ports opening into a bore in the housing, a spool axially slidable in the bore and slot defining a bypass passageway extending between the two ports and variable in cross section upon axial movement of the spool. The spool is spring-biased in a direction to close the bypass passageway, but attractable by an energized solenoid to open the bypass passageway when the solenoid is supplied with an electric current dependent on the speed of travel of the vehicle. The spool has therein a restrictor disposed in the bypass passageway adjacent to the slot to restrict the flow of a fluid through the bypass passageway into and out of the bore in the housing. The restrictor develops a pressure drop while the fluid flows through the bypass passageway to maintain the spool substantially in equilibrium while the fluid under pressure flows through the bypass passageway in either direction upon axial shifting of the spool. The solenoid-operated valve enables dirigible wheels to be assisted in getting turned to the right or left by equal or balanced steering forces generated by the power steering system.

Linear solenoid-operated valve for use in power steering system

Method for producing a pressure plate used in a hydraulic pump by connecting first and second plate sections together include the steps of pressing metal powders to individually form the first and second plate sections and a ring member into predetermined configurations, placing the first plate section properly on the second plate section while the ring member is inserted in a bore formed in the first plate section, placing brazing metal along the upper side diameter of the bore, and heating the first and second plate sections and the ring member so as to connect the first and second plate sections and the ring member together by the brazing metal and simultaneously sintering the same.

Method for producing pressure plates used in hydraulic pumps

A vane type hydraulic pump for use in a power steering apparatus comprising a pump housing receiving therein a non-rotatable cam ring and non-rotatable but axially slidable pressure plate and subplate. A pump rotor rotatable integrally with a drive shaft is received in an internal cam bore of the cam ring and, when rotated, delivers pressurized fluid to a discharge port connected to the power steering apparatus. The pressure plate and subplate define at a contact portion therebetween a radial low pressure passage, which is fluidically communicated with an axial low pressure hole receiving fluid from a pump reservoir and bypassed fluid from a flow volume control valve. The radially outer portions of the low pressure passage are gradually curved in a direction of rotation of the pump rotor.

Hydraulic pump for power steering

In a power steering device for a vehicle, a first spool valve member is slidably received in a valve housing and is supplied with a steering pressure generated in response to a manual steering torque. A second spool valve member is slidably received in the first spool valve member and is supplied with a control pressure depending upon a vehicle speed. Bypass means is formed on the first and second spool valve members to be actuated by the control pressure to communicate both cylinder chambers of a manual steering torque supplementing hydraulic actuator with each other. Relative displacement between the first and second spool valve members is caused by the steering pressure to act to close the bypass means.

Power steering device

A power steering apparatus comprises a main valve member rotating in response to the action of a fluid pressure motor supplementing manual steering torque and a flap valve member rotating in response to the manual steering torque and mounted within the main valve member. The main valve member and the flap valve member are operable to control flow of fluid under pressure supplied into and discharged from the fluid pressure motor. A plunger member is slidably received in the flap valve member and is provided with an anti-vibration member. A passage communicating with a fluid supply port is provided for applying fluid under pressure to the plunger member to urge the anti-vibration member against the main valve member.

Power steering apparatus

A continuously variable speed converter is provided wherein a plurality of balls are interposed between a pair of friction discs for transmitting rotation of an input shaft to an output shaft connected with a fluid pump. A speed change mechanism is arranged to tilt the rotational axis of each of the balls in each plane, including the axis of the input shaft, to thereby change the output/input speed ratio. Disposed within a main housing carrying the input and output shafts is the fluid pump, which also serves as a pressuring means responsive to fluid delivered by itself so as to apply to the output shaft a thrust force corresponding to the pressure of the fluid, so that efficient power transmission without slippage may be provided between the friction discs and the balls.

Continuously variable speed converter for cooperative use with a fluid

A continuously variable speed converter is incorporated in a main housing of a fluid pump and is drivingly connected at an output shaft thereof to a pump rotor so as to transmit the driving power of an engine to the pump rotor at various output/input speed ratios. An actuator is operatively connected at its piston to a speed change mechanism of the speed converter and is responsive to pressurized fluids, which are delivered from the pump, respectively, through and not through a throttle element provided on an outlet passage of the pump. The piston is biased by means of a spring to operate the speed change mechanism to maintain constant the pressure difference between fluids before and behind the throttle element, so that fluid may be delivered from the pump approximately at a predetermined flow rate regardless of changes in engine rotational speed.

Fluid pump with a continuously variable speed converter

A servo valve device in a power steering apparatus of a vehicle, which has a main valve member provided with two valve chambers and disposed to rotate in response to one of the action of a fluid pressure motor supplementing manual steering torque and a manual steering torque, and which has two flap valve members respectively located in the two valve chambers and disposed to rotate in response to the other of the action of the fluid pressure motor and the manual steering torque for controlling fluid under pressure for the fluid pressure motor. The two valve chambers are formed by fluid-tightly partitioning an axial slot formed within the main valve member at a plane containing the rotational axis thereof, and the two flap valve members are integrally formed with each other.

Servo valve device in power steering apparatus

A power steering apparatus for a vehicle comprising: a hydraulic actuator for supplementing manual steering torque; a first valve means for controlling directions of pressure fluid supplied to the hydraulic actuator in response to manual steering; a second valve means for reducing the supplementing force of the hydraulic actuator by by-passing the pressure fluid; a vehicle speed detecting means for detecting the cruising speed of the vehicle; first switching means responsive to the vehicle speed detecting means for supplying electric energy to the second valve means when the cruising speed exceeds a predetermined value; and second switching means for decreasing electric energy supplied to the second valve means when the second valve means starts to by-pass the pressure fluid.

Growing community of inventors

Aichi, Japan

Minoru Kawabata