Abstract: An electric pump includes a pump configured to suck, pressurize and discharge working fluid, a motor coupled with the pump and configured to drive the pump, a motor controller arranged laterally to the motor and configured to control the drive of the motor, and a cooling unit arranged between the motor and the motor controller and configured to cool the motor controller by a refrigerant circulating inside. The cooling unit includes a raised portion projecting into an inner space of the motor controller and formed with a flow passage for the circulation of the refrigerant inside.

Abstract: A steering-shaft-rotation-angle detection device that detects a rotation angle of a steering shaft that is rotated by operation of a steering wheel, includes an electric motor that assists steering of the steering wheel by a driver, a speed reduction mechanism that reduces speed of rotation of the electric motor and transmits the rotation to the steering shaft, a rotating body that is attached to a rotation shaft of the electric motor, a signal output unit that outputs a signal in accordance with rotation of the rotating body, and a controller that calculates a rotation angle of the rotating body on the basis of the output signal from the signal output unit and calculates, on the basis of this rotation angle and a speed reduction ratio of the speed reduction mechanism, a rotation angle of the steering shaft.

Abstract: A steering-shaft-rotation-angle detection device that detects a rotation angle of a steering shaft that is rotated by operation of a steering wheel, includes an electric motor that assists steering of the steering wheel by a driver, a speed reduction mechanism that reduces speed of rotation of the electric motor and transmits the rotation to the steering shaft, a rotating body that is attached to a rotation shaft of the electric motor, a signal output unit that outputs a signal in accordance with rotation of the rotating body, and a controller that calculates a rotation angle of the rotating body on the basis of the output signal from the signal output unit and calculates, on the basis of this rotation angle and a speed reduction ratio of the speed reduction mechanism, a rotation angle of the steering shaft.

Abstract: A controller samples a motor current value detected by a motor current detector at a sampling start timing for turning on a switching device to start holding in a motor current hold section, and fetches the motor current value held in the motor current hold section at a hold timing for turning off the switching device. The sampling start timing and the hold timing are variable.

Abstract: A controller samples a motor current value detected by a motor current detector at a sampling start timing for turning on a switching device to start holding in a motor current hold section, and fetches the motor current value held in the motor current hold section at a hold timing for turning off the switching device. The sampling start timing and the hold timing are variable.

Abstract: An electric power steering system remaining stable when subjected to forces from the road surface, the engine or motor, or from other sources. The electric power steering system has a torque sensor for outputting a signal corresponding to the value of the steering torque, a derivative component for outputting a signal obtained by differentiating the output signal of the torque sensor, a driver for electrically driving an assist apparatus which assists a steering force, an assist current determining component for determining current flowing to the driver in accordance with the output signal of the torque sensor and the output signal of the derivative, and a gain control for setting a gain of the derivative component to zero or reducing the gain when the output signal of the torque sensor is smaller than a predetermined value. Methods to provide a stable steering system are also part of the subject matter.

Abstract: A potentiometer to be utilized in an electric power steering system of a vehicle for generation of assist torque. The power steering system includes a torsion bar spring which receives steering torque and is twisted by the torque. The potentiometer comprises a magnet device having two magnetic polar faces, which create a magnetic field and a magneto-sensitive device placed in the magnetic field. The magnet device is rotatable relative to the magneto-sensitive device in proportion to the twist of the torsion bar spring and changes the relative angle between the magneto-sensitive device and the magnetic field causing the potentiometer to generate voltage for use in generating assist torque.

Abstract: A challenge of the present invention is to provide a system for controlling electric power steering which does not allow a pulsing motion to occur when a steering wheel W is positioned around the middle position. To answer the challenge, the system has signal level decision means 16 for selecting a reference level or an amplification level in response to a steering-torque detection signal or a motor current command-value signal; first adjustment device 17 for carrying out the selection of the reference level or the amplification level for the signal level of the motor current command-value signal; second adjustment device 18 for carrying out the selection of the reference level or the amplification level for the signal level of the motor current detection signal; Ad conversion device 15 for converting the signal sent from the second adjustment signal into a digital signal; and third adjustment device 19 for adjusting the motor current control signal to be at the reference level.

Abstract: A problem to be solved by the present invention is that, in a conventional system for controlling electric power steering, as the number of revolutions of a motor is increased, an assist force decreases, resulting in faulty steering response.

Abstract: An electric power steering system that is stable when subjected to forces from the road surface, the engine or motor, or from other sources. The electric power steering system has a torque sensor for outputting a signal corresponding to the value of the steering torque, a derivative means for outputting a signal obtained by differentiating the output signal of the torque sensor, a driving means for electrically driving an assist apparatus which assists a steering force, an assist current determining means for determining current flowing to the drive means in accordance with the output signal of the torque sensor and the output signal of the derivative means, and a gain control means for setting a gain of the derivative means to zero or reducing the gain when the output signal of the torque sensor is smaller than a predetermined value. Methods to provide a stable steering system are also part of the subject matter.

Abstract: An object of the present invention is to provide a compact torque detector. The present invention solving the object has a conversion member 23 provided on the outer circumferences of an input shaft 20 and an output shaft 21 to convert the amount of relative rotation of the input and output shafts to a displacement in the axial direction; an annular-shaped ring member 26 secured on the outer circumference of the conversion member 23 and made up of a magnet; and a plurality of magnetically sensitive devices 27 arranged at intervals around the ring member 26 and facing the ring member. The magnetically sensitive device 27 detects the amount of travel of the ring member 26 in the axial direction and supplying the detected amount as a voltage signal to a controller C.

Abstract: A potentiometer to be utilized in an electric power steering system of a vehicle for generation of assist torque. The power steering system includes a torsion bar spring which receives steering torque and is twisted by the torque. The potentiometer comprises a magnet device having two magnetic polar faces, which create a magnetic field and a magneto-sensitive device placed in the magnetic field. The magnet device is rotatable relative to the magneto-sensitive device in proportion to the twist of the torsion bar spring and changes the relative angle between the magneto-sensitive device and the magnetic field causing the potentiometer to generate voltage for use in generating assist torque.

Abstract: An object of the present invention is to provide a compact torque detector. The present invention solving the object has a conversion member 23 provided on the outer circumferences of an input shaft 20 and an output shaft 21 for convert the amount of relative rotation of the input and output shafts to a displacement in the axis direction; an annular-shaped ring member 26 secured on the outer circumference of the conversion member 23 and made up of a magnet; and a plurality of magnetically sensitive devices 27 arranged at intervals around the ring member 26 and facing the ring member. The magnetically sensitive device 27 detects the amount of travel of the ring member 26 in the axis direction and supplying the detected amount as a voltage signal to a controller C.

Abstract: A challenge of the present invention is to provide a system for controlling electric power steering which does not allow a pulsing motion to occur when a steering wheel W is positioned around the middle position. To answer the challenge, the system has signal level decision means 16 for selecting a reference level or an amplification level in response to a steering-torque detection signal or a motor current command-value signal; first adjustment means 17 for carrying out the selection of the reference level or the amplification level for the signal level of the motor current command-value signal; second adjustment means 18 for carrying out the selection of the reference level or the amplification level for the signal level of the motor current detection signal; Ad conversion means 15 for converting the signal sent from the second adjustment signal into a digital signal; and third adjustment means 19 for adjusting the motor current control signal to be at the reference level.

Abstract: A problem to be solved by the present invention is that, in a conventional system for controlling electric power steering, as the number of revolutions of a motor is increased, an assist force decreases, resulting in faulty steering response.

Abstract: A motorized power steering control device capable of reducing arrangement of an external wiring and simplifying a travel condition detecting unit, to thereby reduce a manufacturing cost of the device. A controller has an alternator pulsation detecting circuit and a power circuit arranged therein. The power circuit selectively controls a main voltage or a backup voltage to apply it to a control circuit. The control circuit operates an engine speed depending on a pulsation frequency of an alternator, to thereby actuate the power circuit to apply the main voltage to the control circuit when the engine speed is at a predetermined level or above and apply the backup voltage thereto when it is at the predetermined level or below.

Abstract: An arrangement of circuit casings and circuit boards in a motorized power steering device including a drive circuit casing, a control circuit casing and a gear casing connected to the drive circuit casing. The drive circuit casing includes a drive circuit board provided thereon with a drive circuit whereas the control circuit casing includes a control circuit board provided thereon with a control circuit for outputting a control signal to the drive circuit. An electric motor is attached to the drive circuit casing such that the drive circuit casing is interposed between the gear casing and the electric motor.