Abstract: A ball screw nut has a pair of through holes and a first passage that allows the through holes to communicate with each other and that opens radially outward. In each of the through holes, a ball screw mechanism has a circulation member having a second passage in which a ball can move between a ball raceway and the first passage. The ball screw mechanism has a circulation path for communicating the two connection points set on the ball raceway by the first passage and each of the second passages. A driven pulley has a thin portion that defines a radial clearance between an inner periphery of the driven pulley and an outer periphery of the ball screw nut. The ball screw mechanism has a pressing lid that presses down each of the circulation members from the outer periphery of the ball screw nut and that covers the first passage.

Abstract: A ball screw nut has a pair of through holes and a first passage that allows the through holes to communicate with each other and that opens radially outward. In each of the through holes, a ball screw mechanism has a circulation member having a second passage in which a ball can move between a ball raceway and the first passage. The ball screw mechanism has a circulation path for communicating the two connection points set on the ball raceway by the first passage and each of the second passages. A driven pulley has a thin portion that defines a radial clearance between an inner periphery of the driven pulley and an outer periphery of the ball screw nut. The ball screw mechanism has a pressing lid that presses down each of the circulation members from the outer periphery of the ball screw nut and that covers the first passage.

Abstract: In a steered shaft in a steering system, when a section of a first end portion having a prescribed length shorter than a length from an end face to an outer peripheral rolling groove is defined as a first section, a section of the first end portion other than the first section and adjacent to the outer peripheral rolling groove is defined as a second section, a section, in the outer peripheral rolling groove, starting from a boundary between the second section and the outer peripheral rolling groove and having a prescribed length shorter than an axial length of a section along which the outer peripheral rolling groove extends is defined as a third section, a maximum value of a hardening depth in the second section is larger than a hardening depth in the first section.

Abstract: An end damper capable of providing an impact absorbing function with a short stroke is provided. A steering system includes: a large-diameter members attached one to each axial end of a rack shaft; a rack housing having stopper portions which the corresponding large-diameter members approach and separate from, the rack housing holding the rack shaft and the large-diameter members movably in an axial direction; and end dampers each of which absorbs impact by being held between the corresponding large-diameter member and the corresponding stopper portion in the axial direction. Each end damper includes: a first elastic member that is elastically deformed by being held; and a second elastic member that is elastically deformed such that an elastic modulus of the entire end damper is greater than an elastic modulus of the first elastic member, by receiving a load resulting from the elastic deformation of the first elastic member.

Abstract: The steering apparatus includes a first seal member and a second seal member. The first seal member is fixed to one of an outer peripheral surface of a rack shaft and an inner peripheral surface of a housing. The first seal member slidably contacts with a cylindrical surface which is centered on the axis and is provided on the other of the outer peripheral surface of the rack shaft and the inner peripheral surface of the housing. The second seal member is fixed to the other of the outer peripheral surface and the inner peripheral surface. The second seal member slidably contacts with a cylindrical surface which is centered on the axis and is provided on the one of the outer peripheral surface of the rack shaft and the inner peripheral surface of the housing.

Abstract: The steering apparatus includes a first seal member and a second seal member. The first seal member is fixed to one of an outer peripheral surface of a rack shaft and an inner peripheral surface of a housing. The first seal member slidably contacts with a cylindrical surface which is centered on the axis and is provided on the other of the outer peripheral surface of the rack shaft and the inner peripheral surface of the housing. The second seal member is fixed to the other of the outer peripheral surface and the inner peripheral surface. The second seal member slidably contacts with a cylindrical surface which is centered on the axis and is provided on the one of the outer peripheral surface of the rack shaft and the inner peripheral surface of the housing.

Abstract: In a hydraulic pump, a cam ring is provided in a cylindrical adaptor for movement in a radial direction, and a differential pressure control valve is provided to control internal pressure and load pressure at the front and back sides of a variable orifice to be introduced into action chambers and formed at the opposite sides of the cam ring for controlling a discharge amount of the pump in accordance with the rotation speed of the pump. The differential pressure control valve is operated under the internal pressure and load pressure respectively introduced into action chambers and the load of a thrust spring biasing the differential pressure control valve toward the internal pressure chamber. The load of the thrust spring is increased or decreased in accordance with an increase or a decrease of the load pressure.

Abstract: In a hydraulic pump, a cam ring 21 is provided in a cylindrical adaptor 13 for movement in a radial direction, and a differential pressure control valve 31 is provided to control internal pressure and load pressure at the front and back sides of a variable orifice 54 to be introduced into action chambers 51a and 51b formed at the opposite sides of the cam ring for controlling a discharge amount of the pump in accordance with the rotation speed of the pump. The differential pressure control valve is operated under the internal pressure and load pressure respectively introduced into action chambers 52a and 52b and the load of a thrust spring 33 biasing the differential pressure control valve toward the internal pressure chamber 52a. The load of the thrust spring is increased or decreased in accordance with an increase or a decrease of the load pressure.

Abstract: A flow control device, responsive to the rotational speed of a pump and to load pressure, has a simple structure. And a housing of the flow control device for saving energy can make use of a general pump housing not for saving energy as a common housing.The flow control device of a power steering apparatus, arranged in a housing of a pump, includes a flow control valve and a load pressure responsive valve. The flow control valve includes a bypass spool with a control rod penetrating a metering orifice. The load pressure responsive valve is incorporated in a union for response to the load pressure. The control rod is located on the bypass spool for response to the rotational speed of the pump.

Abstract: In a flow control device for vehicles and like, a union 17 of a pump receives a load pressure responsive valve 24. The union 17 is provided with outlet port to supply operating fluid regulated by a flow control valve to a control valve. The load pressure responsive valve, received in the union, has a variable orifice. The load pressure responsive valve brings the spring chamber into communication with the reservoir when road pressure, caused by operation of a steering wheel, is relatively low and the load pressure responsive valve shuts the communication between the spring chamber and the reservoir in response to rising of the road pressure. Therefore, the flow control device provides the power saving caused by decreasing the flow rate supplied from the pump to the control valve at low load pressure without substantial improvement of a pump housing.

Abstract: A hydraulic power steering apparatus includes a motor-driven pump which discharges pressurized working fluid at a flow rate proportional to the rotational speed. A load-pressure responsive valve is connected to a discharge passage to which the pressurized fluid is discharged from the pump. The load-pressure responsive valve bypasses the pressurized fluid to a reservoir when the control valve is in a neutral state, thereby reducing the amount of the pressurized fluid supplied to the control valve, and increases the amount of the pressurized fluid supplied to the control valve when the load pressure of the pump increases upon operation of the control valve. With this control, the energy consumed by the pump can be reduced.

Abstract: A hydraulic power steering system includes a pump, a flow control valve, and a bypass control valve. The flow control valve responds to a pressure drop across a metering orifice disposed in a fluid supply passage so as to control the flow rate of operating fluid by bypassing a part of the operating fluid to a reservoir. A spring chamber of the flow control valve is connected to the supply passage through a control orifice. The bypass control valve is disposed between the spring chamber and the reservoir so as to increase the amount of bypassed fluid by controlling the pressure in the spring chamber. The bypass control valve has a control spool, a load pressure introduction port connected to the upstream side of the control orifice for leading the load pressure to a first end of the control spool and a pilot port connected to the downstream side of the control orifice for leading the pressure in the spring chamber of the flow control valve to a second end of the control spool.

Abstract: A power steering apparatus having a fluid source for discharging pressurized fluid, a power cylinder, a control valve responsive to operation of a steering wheel for supplying the power cylinder with pressurized fluid from the fluid source, and a reservoir. The control valve has a first control portion for controlling the flow of pressurized fluid from the fluid source to the reservoir, and a second control portion for controlling the flow of pressurized fluid to the power cylinder. The first control portion has two paths connecting the fluid source and the reservoir, each of the paths being formed with at least one variable orifice of a center-open type which opens when the control valve is in a neutral state.

Abstract: A hydraulic power steering system includes a pump, a flow control valve, and a bypass control valve. The flow control valve responds to a pressure drop across a metering orifice disposed in a fluid supply passage so as to control the flow rate of operational fluid by bypassing part of the operational fluid to a reservoir. A spring chamber of the flow control valve is connected to the supply passage through a control orifice. The bypass control valve is disposed between the spring chamber and the reservoir so as to increase the amount of bypassed fluid by controlling the pressure in the spring chamber. The bypass control valve has a control spool, a load pressure introduction port connected to the upstream side of the control orifice for leading the load pressure to a first end of the control spool and a pilot port connected to the downstream side of the control orifice for leading the pressure in the spring chamber of the flow control valve to a second end of the control spool.

Abstract: A power steering apparatus for a motor vehicle is provided with a metering orifice arranged on a supply passage and a flow control device in parallel relation with the metering orifice. The flow control valve includes a spool and a spring and moves the spool against the force of the spring in response to the pressure difference across the metering orifice for returning an excess part of operating fluid discharged from an engine-driven pump to an intake side of the pump so as to keep the flow rate towards a power assist gear unit almost constant regardless of changes in rotational speed of the pump. A drooping device cooperating with the flow control valve is provided comprising a control orifice at the upstream of the metering orifice and a bypass valve in communication with a spring chamber of the flow control valve retaining the spring.

Abstract: A power steering apparatus having a hydraulic pump for outputting a pressurized fluid, an assist force generation mechanism hydraulically connected to the pump through a supply passage to generate an assist force in response to rotation of a steering wheel, wherein the assist force generation mechanism has a characteristic that the back pressure thereof increases when the steering wheel is rotated. The power steering apparatus further comprises a flow control valve having a spool which is moved in response to a pressure drop at a metering orifice disposed in the middle of the supply passage, so as to control the flow rate of the pressurized fluid to be constant.

Abstract: A variable-displacement vane pump apparatus is composed of a pump part and a switching valve. The pump part is comprised of a housing, a cam ring, a rotor, plural vanes, side plates, two pairs of intake and exhaust ports formed on the side plates, discharge pressure chambers connecting with the discharge ports, and an intake chamber connected with the intake ports. The pump part is divided into first and second pump portions, and only one of the pump portions is activated by the operation of the switching valve when the load pressure is low. Under such condition, the fluid discharged from the particular pump portion is returned to its intake port. Also, the flow rate of the operation fluid discharged from the pump is adjusted by the flow control valve by returning part of pressurized fluid into the inlet ports. A fluid supplied from a reservoir is energized two times by supercharge effect utilizing the returned fluid from the switching valve and the returned fluid from the flow control valve.

Abstract: A flexible magnetic disk drive is disclosed which has a transducer head requiring little or no positional or angular readjustment for proper data transfer contact with a flexible magnetic disk in the face of possible dimensional or mounting errors. The transducer head has a rounded contact surface for data transfer contact with the flexible magnetic disk, in which surface is defined a transducing gap, typically a read/write gap. The transducing gap is offset toward the axis of the magnetic disc from a notional line right angularly crossing, at the apex of the contact surface, another notional line connecting the apex of the contact surface and the center of the magnetic disk. So positioned on the contact surface, the transducing gap is practically free from the wobbling motion of that part of the rotating magnetic disk which is radially outward of its points of contact with the transducer head and with a pressure pad.