Abstract: A power steering apparatus includes a power cylinder including first and second pressure chambers, a hydraulic pump including first and second discharge ports, the hydraulic pump being arranged to supply a hydraulic pressure selectively to the first and second pressure chambers; first and second hydraulic passages connecting the first and second pressure chambers and the first and second discharge ports; a motor arranged to drive the hydraulic pump; a motor control section configured to output a drive signal to the motor; a reservoir tank storing a hydraulic fluid; first and second bypass passages connecting the first and second hydraulic passages and the reservoir tank; first and second bypass valves arranged to open and close the first and second bypass passages; and first and second flow rate restricting sections disposed in the first and second bypass passages, and arranged to decrease flow rates of the first and second bypass passages.

Abstract: In a pump device applicable to a power steering apparatus, a pump element is housed within a pump housing and is configured to drain a working oil, an electric motor is configured to drive the pump element, a reservoir tank is installed on the housing and is configured to reserve the working oil supplied to the oil element, a passage is formed within the pump housing and is connected to the pump element, and a control valve is installed in the pump housing, is configured to communicate with the passage, and is configured to control a flow of the working oil caused to flow through the passage.

Abstract: In a power-cylinder equipped power steering device, under a first condition where a first directional control valve disposed in a first pressure line receives fluid pressure supplied into a second pressure line by a reversible pump, the first directional control valve intercommunicates a reservoir and a first-pressure-line downstream passage section, and blocks fluid communication of the first-pressure-line upstream and downstream passage sections. Under a second condition where a second directional control valve receives fluid pressure supplied into the first pressure line by the pump, the first directional control valve intercommunicates the first-pressure-line upstream and downstream passage sections. Under the second condition, the second directional control valve intercommunicates the reservoir and the second-pressure-line downstream passage section, and blocks fluid communication of the second-pressure-line upstream and downstream passage sections.

Abstract: A power steering apparatus includes a hydraulic power cylinder, and a reversible pump driven by a motor. A steering assist sensor senses a steering assist force provided to a steering wheel. A controller ascertains a pump discharge quantity of the reversible pump, and a cylinder volume variation of the pressure chambers of the hydraulic power cylinder; and calculates a leak quantity of the reversible pump from a difference between the pump discharge quantity and the cylinder volume variation. The controller controls the motor to cause the motor to produce a desired fluid pressure in accordance with the steering assist force and the leak quantity.

Abstract: A power steering system includes a hydraulic power cylinder having a first and a second hydraulic chambers, for assisting a steering force of a steering mechanism, a first and a second oil passages respectively connected to the first and second hydraulic chambers, a reversible pump discharging operating oil and providing oil pressure to the hydraulic power cylinder through the first and second oil passages, and a motor connected to the reversible pump and rotating the reversible pump in normal and reverse directions. A steering load detection unit detects a steering load of a steering wheel for steering of the steered road wheels, and a motor control unit outputs a control signal to the motor to bring an actual oil pressure generated by the reversible pump closer to a desired oil pressure determined based on the detected steering load. A discharge amount per rotation of the reversible pump is smaller than or equal to 5 cc.

Abstract: A power steering system includes first and second drain passages connected to the first and second passages, respectively, and first and second passage switching valves arranged at connections of the first and second drain passages and the first and second passages, respectively. When a hydraulic pump operates to discharge the hydraulic pressure to the first passage, the first passage switching valve provides fluid communication between pump-side and cylinder-side portions of the first passage and closes off the first drain passage. And when the hydraulic pump stops, the first switching valve provides fluid communication between the cylinder-side portion of the first passage and the first drain passage.

Abstract: An inscribed gear pump that provides a housing, an outer rotor formed with a plurality of inner teeth continuously at an internal circumference thereof which is rotatably provided to an inside of the housing, an inner rotor formed with a plurality of outer teeth continuously at an external circumference thereof which is rotatably provided to an inside of the outer rotor, drive shaft rotatably drives the inner rotor. Volume chambers which are formed between the inner teeth and the outer teeth. A suction port is open at an area of the volume chamber increase in a volume gradually. A discharge port is open at an area of the volume chamber that decreases in a volume gradually. An area between a start portion of the suction port and an end portion of the discharge port have contact portions of the inner teeth and outer teeth, where the number is an integer more than 2 at a portion of a volume chamber having a maximum volume of a side of a trap portion.

Abstract: An output end and an inverted output end of a latch circuit that is connected to an output buffer circuit are switched with each other, and thereby, the relationship between the data of “0” or “1” and the drain of a memory cell is connected or not connected to a bit line is changed. In addition, an input of a sense amplifier is fixed at the grounding potential by means of a test control signal, and thereby, positive logic is confirmed in the case where the output of the output buffer circuit is “L,” and negative logic is confirmed in the case where the output of the output buffer circuit is “H.

Abstract: A power steering system for a vehicle. The system includes a hydraulic power cylinder, first and second hydraulic lines, a bypass passage through which the first and second hydraulic lines are connected with each other, and a flow passage change-over device adapted to close the bypass passage during steering assisting. A supply passage and a return passage are disposed in parallel with each other to form part of each of the first and second hydraulic lines. The flow passage change-over device is disposed in each of the first and second hydraulic lines. A differential pressure regulating valve is disposed in each of the return passages and adapted to allow hydraulic fluid to flow toward the hydraulic pressure source in a condition where pressure on side of the hydraulic power cylinder becomes higher than a set pressure or higher than pressure on side of the hydraulic pressure source.

Abstract: A semiconductor memory device includes a memory cell array, a charge circuit which compensates for OFF leakage current developed at selected bit lines, a reset circuit having a ground potential corresponding to a potential at non-selected bit lines, a read circuit constituted by a plurality of transistors whose gates are connected to the bit lines, and a bit line precharge circuit which charges the selected bit lines for a fixed time period. As a result of adopting such a configuration, there is no need to provide a transmission gate, such as a column decoder, to a charging path between the read circuit and the bit lines, so that a low-power supply voltage operation can be effected without the influence of a substrate bias effect.

Abstract: According to a conventional semiconductor memory device, in a replica circuit composed of a plurality of dummy bit lines, an off leakage current of a transistor has been significantly increased with the advance of a semiconductor microfabrication technology, so that the dummy bit line has not been able to be charged to a desired potential due to the off leakage current when charging. As a result of this, since a charging period or a discharging period of the dummy bit line is also different from a desired period, the optimal operation timing may not be set. In a dummy memory cell array, in order to connect a drain region 21 and a first dummy bit line 25, the first dummy bit line 25 is connected via contact and via holes 28 through 30 and metal electrodes 23 and 24, while a second dummy bit line 46 does not contact to a drain region 47.

Abstract: A power steering system and a method of charging the power steering system with hydraulic fluid are provided. Hydraulic fluid is selectively supplied to hydraulic chambers of a power cylinder via oil passages from a reversible pump, according to a steering torque. In addition, a bypass passage is provided between oil passages. A normally open switching valve is provided in the bypass passage. When the system is assembled, the hydraulic fluid is supplied from an oil reservoir via the switching valve or the reversible pump, and circulated in the hydraulic circuit. The air in the hydraulic circuit is discharged via the switching valve.

Abstract: To provide a nonvolatile memory microcomputer with which a step of testing a microcomputer unit using a logic tester can be omitted, thereby reducing the testing cost. A memory tester supplies test data and expectation data to the nonvolatile memory microcomputer, and the nonvolatile memory microcomputer stores them in a nonvolatile memory. Subsequently, upon receiving an address signal, the nonvolatile memory outputs a test signal and an expectation signal based on test data and expectation data corresponding to the address signal. The test signal is supplied to a circuit block in the microcomputer unit, to drive the circuit block. The circuit block returns a test result signal, which is output to the memory tester together with the expectation signal. The memory tester compares the test result signal and the expectation signal, to judge whether the microcomputer unit operates correctly.

Abstract: An oil pump comprises a cam ring, an outer rotor having inner teeth, which is rotatably provided inside of the cam ring, an inner rotor having outer teeth, which is engageable with the inner teeth of the outer rotor, a drive shaft which ratatably drive the inner rotor. A first housing and second housing are provided at opposite ends of the cam ring. A plurality of volume chambers are formed between the inner teeth of the outer rotor and the outer teeth of the inner rotor. A first axial hole is formed in the cam ring and is positioned corresponding to a mesh portion having a minimum volume of the volume chambers. A second axial hole is formed in the cam ring and is positioned corresponding to a trap portion having a maximum volume of the volume chambers. A suction port and a discharge port are formed at least in one of said housings and are open to the volume chambers between the mesh portion and the trap potion.

Abstract: A power steering apparatus includes a hydraulic power cylinder, and a reversible pump driven by a motor. A steering assist sensor senses a steering assist force provided to a steering wheel. A controller ascertains a pump discharge quantity of the reversible pump, and a cylinder volume variation of the pressure chambers of the hydraulic power cylinder; and calculates a leak quantity of the reversible pump from a difference between the pump discharge quantity and the cylinder volume variation. The controller controls the motor to cause the motor to produce a desired fluid pressure in accordance with the steering assist force and the leak quantity.

Abstract: A trochoid pump for supplying hydraulic fluid to a power cylinder in a power steering system. The trochoid pump includes a housing formed therein with an annular operating chamber. Outer rotor having internal teeth and inner rotor having external teeth are rotatably accommodated in the operating chamber in such a manner that the internal and external teeth are engageable with each other. A driving shaft is provided for rotationally driving the inner rotor. A low pressure passage is opened to a clearance between an outer peripheral surface of the outer rotor and an inner peripheral surface of the operating chamber within a discharge region at side of an engaging section at which the volume of the pump chamber is the minimum so as to release a high pressure applied to the outer peripheral surface of the outer rotor, to a low pressure side.

Abstract: An output end and an inverted output end of a latch circuit that is connected to an output buffer circuit are switched with each other, and thereby, the relationship between the data of “0” or “1” and the drain of a memory cell is connected or not connected to a bit line is changed. In addition, an input of a sense amplifier is fixed at the grounding potential by means of a test control signal, and thereby, positive logic is confirmed in the case where the output of the output buffer circuit is “L,” and negative logic is confirmed in the case where the output of the output buffer circuit is “H.

Abstract: A power steering system includes: a first drain passage for draining an oil pressure from a first oil passage, a second drain passage for draining the oil pressure from a second oil passage, and a pair of a first and second switch valves. When one of the first oil passage and the second oil passage is so pressurized by an operation of a reversible oil pump as to have an increased internal pressure, the pair of the first switch valve and the second switch valve allow the following: i) closing one of the first drain passage and the second drain passage which one is connected to the oil passage having the thus increased internal pressure, while ii) opening the other of the first drain passage and the second drain passage which other is connected to the oil passage that is so depressurized as to have a decreased internal pressure.

Abstract: A power steering system for a vehicle, comprises a steering shaft connected to a steering mechanism. A hydraulic power cylinder is provided for assisting a steering effort of the steering mechanism. A reversible pump is provided having first and second discharge ports which are respectively connected through first and second hydraulic lines with two hydraulic pressure chambers of the hydraulic power cylinder so that the two hydraulic pressure chambers are respectively provided with hydraulic pressures. A driving device is provided for driving the reversible pump to rightly and reversely rotate. A differential pressure regulating valve is disposed in the hydraulic circuit to maintain pressure at least in the first and second hydraulic lines at a level of atmospheric pressure or higher in an inoperative condition of the reversible pump.

Abstract: A first fluid passage extends from a first outlet/inlet port of a hydraulic pump to a first work chamber of a power cylinder, and a second fluid passage extends from a second outlet/inlet port of the pump to a second work chamber of the power cylinder. A switch system switches the role of the first and second outlet/inlet ports in accordance with a turning direction of a steering wheel. Flow control mechanisms are respectively incorporated with the first and second fluid passages, so that a controlled flow of hydraulic fluid from the hydraulic pump to the first or second work chamber and vice versa are appropriately carried out thereby providing the driver with a comfortable steering feeling. A bypass arrangement may be provided between the first and second fluid passages to deal with a residual pressure that would be remained in the first or second work chamber when the hydraulic pump is under inoperative condition.