Abstract: A steering operation input apparatus is for allowing a predetermined neutral position to be acquired regardless of a direction in which a nut is mounted. In a mechanical stopper mechanism, a central position of the nut in an axial direction aligns with a central position of a crest and a central position of a root of an externally threaded portion with a steering wheel in a neutral state. A first imaginary line extends in a direction perpendicular to a rotational axis and passes through the crest and the root, and a second imaginary line extends perpendicularly to the first imaginary line on a line of the rotational axis in a cross section perpendicular to the rotational axis at the central position of the nut, and a pin is symmetric about the first imaginary line and asymmetric about the second imaginary line.

Abstract: The present invention provides a steering operation input apparatus that allows a predetermined neutral position to be acquired regardless of a direction in which a nut is mounted. In a mechanical stopper mechanism according to a first embodiment, a central position of a nut in an axial direction aligns with a central position of a crest and a central position of a root of an externally threaded portion with a steering wheel placed in a neutral state. Assuming that a first imaginary line is set so as to extend in a direction perpendicular to a rotational axis and pass through the crest and the root and a second imaginary line is set so as to extend perpendicularly to the first imaginary line on a line of the rotational axis in a cross section perpendicular to the rotational axis at the central position of the nut, a pin is symmetric about the first imaginary line and asymmetric about the second imaginary line.

Abstract: An object of the present invention is to provide a ball screw having a structure in which a screw shaft and a nut satisfy required performance and having improved durability, a method for manufacturing the ball screw, a power steering device, and a method for manufacturing the power steering device. A ball screw according to the present invention includes: a nut made of a steel substrate having an inner peripheral surface on which a female screw is formed; a screw shaft that is combined with the nut and is made of a steel substrate having an outer peripheral surface on which a male screw facing the female screw is formed; and a plurality of balls arranged between the female screw and the male screw. A surface of the nut in contact with the ball and a surface of the screw shaft in contact with the ball each have carburized layers. A carbon concentration in the carburized layer of the nut is higher than a carbon concentration in the carburized layer of the screw shaft.

Abstract: An object of the present invention is to provide a ball screw having a structure in which a screw shaft and a nut satisfy required performance and having improved durability, a method for manufacturing the ball screw, a power steering device, and a method for manufacturing the power steering device. A ball screw according to the present invention includes: a nut made of a steel substrate having an inner peripheral surface on which a female screw is formed; a screw shaft that is combined with the nut and is made of a steel substrate having an outer peripheral surface on which a male screw facing the female screw is formed; and a plurality of balls arranged between the female screw and the male screw. A surface of the nut in contact with the ball and a surface of the screw shaft in contact with the ball each have carburized layers. A carbon concentration in the carburized layer of the nut is higher than a carbon concentration in the carburized layer of the screw shaft.

Abstract: A brake apparatus including a housing, a piston body disposed within each of a pair of closed-ended bores formed in the housing, a first elastic member that biases the piston body toward a closed end of the respective bores, a fluid passage opened to the closed end of the respective bores, a pressure regulating valve disposed in the fluid passage, and a rotary gear pump disposed in a region between the pressure regulating valve disposed in the fluid passage opened to the closed end of one of the bores and the pressure regulating valve disposed in the fluid passage opened to the closed end of the other of the bores. The fluid passages are formed to be offset from respective central axes of the piston bodies in such a direction that the fluid passages are spaced apart from each other.

Abstract: A brake apparatus including a piston body disposed in a closed-ended bore in a housing, a first elastic member biasing the piston body toward a closed end of the bore, and a pressure regulating valve including a valve element, a rod and a second elastic member biasing the valve element toward a seat portion and having an elastic force smaller than that of the first elastic member, the brake apparatus having a reservoir function of reserving brake fluid flowed from a vehicular wheel cylinder in the bore by strokes of the piston body upon ABS control, the piston body being a resin-molded member having a hard member on a piston crown surface, the hard member having a hardness larger than that of a resin material of the piston body, and the piston body and the rod are brought into contact with each other via the hard member.

Abstract: A brake apparatus including a housing, a piston body disposed within each of a pair of closed-ended bores formed in the housing, a first elastic member that biases the piston body toward a closed end of the respective bores, a fluid passage opened to the closed end of the respective bores, a pressure regulating valve disposed in the fluid passage, and a rotary gear pump disposed in a region between the pressure regulating valve disposed in the fluid passage opened to the closed end of one of the bores and the pressure regulating valve disposed in the fluid passage opened to the closed end of the other of the bores. The fluid passages are formed to be offset from respective central axes of the piston bodies in such a direction that the fluid passages are spaced apart from each other.

Abstract: A brake apparatus including a piston body disposed in a closed-ended bore in a housing, a first elastic member biasing the piston body toward a closed end of the bore, and a pressure regulating valve including a valve element, a rod and a second elastic member biasing the valve element toward a seat portion and having an elastic force smaller than that of the first elastic member, the brake apparatus having a reservoir function of reserving brake fluid flowed from a vehicular wheel cylinder in the bore by strokes of the piston body upon ABS control, the piston body being a resin-molded member having a hard member on a piston crown surface, the hard member having a hardness larger than that of a resin material of the piston body, and the piston body and the rod are brought into contact with each other via the hard member.