Abstract: In the power steering apparatus, a casing comprises integrated separate sections of a valve casing in which a control valve is incorporated, a cylinder tube of a power cylinder, and a gear casing in which a steering gear is incorporated. In the cylinder tube are formed a pair of supply/discharge passages, which are parallel to the axial direction of the cylinder tube, and through which hydraulic fluid flows into/from the power cylinder. In the gear casing are formed, by casting, a pair of pipes which communicate with a pair of supply/discharge passages. In the valve casing are formed a pair of supply/discharge ports which communicate with the pair of pipes.

Abstract: A method for forming a groove by plastic deformation to provide improved working efficiency. A hole 4 having a diameter larger than a width W of a desired groove 6 and a depth deeper than the desired depth of the groove 6 is formed in an end face 2 of a rod 1. Subsequently, the groove 6 is formed by plastic deformation to partially overlap the hole 4. The plastic working to form the groove may be carried without the use of a die.

Abstract: A variable-pitch racked bar has a row of rack teeth with a middle fixed pitch region and two end fixed pitch regions. A variable-pitch region is interposed between the middle fixed pitch region and each of the end fixed pitch regions. In the variable-pitch region, the pitch increases from the fixed, small-pitch middle region toward the fixed, large-pitch end regions. In the variable-pitch racked bar, the effective meshing width continuously decreases from the middle of the row of rack teeth toward both ends thereof.

Abstract: In an electromotive power steering device, when input is received in a reverse direction, i.e., from the road, no assist torque connection is made in the reverse direction. The upper inertial moment is appropriately compensated for. Detection signals from each sensor are received and converted to an input torque, vehicle speed and phase angle. An assist torque command value is calculated from the input torque and the vehicle speed, and an angular velocity and angular acceleration are calculated from the phase angle. Subsequently, the inertial moment of the steering wheel is read and multiplied by the angular acceleration, thereby computing the inertial torque of the steering wheel. It is then determined whether the multiplication of the input torque and the angular velocity results in a positive value or a negative value. Only when the value is positive, correction is made of the assist torque command value.

Abstract: A method of producing a spindle that can be easily press fit into a knuckled suspension arm with high productivity. A round bar is forged by a header to form a work in process part which is, in turn, thermally refined. If necessary, shot blast and lubrication are applied to the exterior surface of the work in process part. Subsequently, by rolling the work in process part, screw threads are formed on a male screw portion. The work in process part is set and finished in a press. The peripheral surfaces of the bearing attachment portion as well as the knuckle press fit portion of the work in process part are finished in a press. Since the surface of the knuckle press fit portion of the spindle is formed or extruded in the press, the portion can be easily press fit into a knuckled suspension arm with little resistance. The method of producing the spindle obviates the necessity of machining and grinding thereby providing enhanced productivity.

Abstract: A device for detecting asynchronization or stepping out of a stepping motor without making the stepping motor large in size. Parallel resonance circuit LC is provided in a recovery circuit of stator coil RL of the stepping motor for detecting linking current IX. If the stepping motor is out of step, the magnetic resistance between stator and rotor increases while the reactance of stator coil RL decreases. When motor drive current ID is turned off, a large transient current is momentarily generated yet is quickly dampened. While the motor drive current ID is off, linking current IX approaches zero. Consequently, if the stepping motor is out of step, there is no substantial difference in the linking current IX when motor drive current ID is turned on from when motor drive current ID was off. Also, the amplitude of the transient or resonance waveform is smaller than the amplitude when the stepping motor is operating normally.

Abstract: A method for fastening an input shaft and a torsion bar together in a power steering mechanism, and the associated torsion bar. A ball-receiving hole is bored in the end of the torsion bar. The end of the torsion bar is inserted into a bore in the input shaft and a ball is pressed into the hole to provide an interference fit between the shaft and the bar. Subsequently, the peripheral edge of the hole in the torsion bar is elliptically deformed so as to retain the ball in the hole and the bar in the shaft. Since a portion of the opening is slightly diametrically broadened by the ball, the periphery of the portion closely contacts the inner wall of the input shaft, thereby strengthening the connection between the torsion bar and the input shaft.