Abstract: A pre-filling device for a braking system. The pre-filling device includes a pre-filling channel, a pre-filling pressure being inside the channel when the braking system is in a rest and hydro-boost position, and a mechanical valve configured to be opened following a transition from the rest and hydro-boost position to a working position of the braking system; and a hydraulic valve cooperating with the mechanical valve setting the pre-filling pressure inside the channel. The hydraulic valve includes in a first area, facing the mechanical valve, a hole communicating with the channel, and in a second area, hydraulically isolated from the first area, a preloaded resilient element in a chamber held at atmospheric pressure. The hydraulic valve is configured to be connected or not to be connected, by a reciprocating movement inside the channel, to a hydro-booster device and to keep a predetermined pre-filling pressure upon varying of the hydro-boost pressure.

Abstract: A hydraulic actuator comprises a cylinder, a piston reciprocatingly received within the cylinder, a piston rod connected to the piston and a pressure release mechanism which allows hydraulic fluid to pass from a first side of the piston to a second side of the piston when the actuator encounters shock loading. This permits the piston to move. The pressure relief mechanism includes a passageway extending from the first side of the piston to the second side of the piston and a valve member adjacent to the passageway which releasably engages the piston. The valve member has a closed position where the valve member closes the passageway and engages the piston. A resilient member biases the valve member towards the closed position. A valve member limiter limits movement of the valve member away from the closed position.

Abstract: A power steering device includes a cylindrical holder coaxially arranged on a steering shaft, a cylindrical rotary cylinder coaxially and rotatably installed in the holder and forming two oil chambers spaced apart in a circumferential direction between it and an inner surface of the holder, and a spool changing-over member coaxially and rotatably inserted in the rotary cylinder and connected to the steering wheel. A differential mechanism is provided between the rotary cylinder and the spool changing-over member for integrally rotating the rotary cylinder and the spool changing-over member when a steering force applied to the steering shaft is low, and allowing a relative rotation between the rotary cylinder and the spool changing-over member when the steering force is larger than a predetermined value.

Abstract: The present invention provides a brake booster that, although simple in construction, capable of adjusting the braking force derived by operation of a solenoid mechanism without worsening the braking response. In the brake booster according to the present invention, when a movable member (34) is shifted toward the rear side by electromagnetic force of a solenoid (31), the shifting movement is transmitted to a valve seat member (21) through pins (50) to open an atmospheric valve (27) through which air is introduced into a variable pressure chamber (9,10), whereby a pressure difference is created between the variable pressure chamber and a constant pressure chamber and generates booster output (thrust output force).

Abstract: A master cylinder and pneumatic brake booster having hydraulic reaction means. The hydraulic reaction means which is mounted to slide within a main piston (12) in the master cylinder includes a central shut-off piston (4), a stepped and hollow reaction piston (5) and a ratio-change piston (6). First (71), second (72) and third (73) springs are associated with said hydraulic reaction means such that a push rod (3) receives only a portion of a reaction force is an actuation force is applied rapidly which is proportional to a difference between an internal cross section of the reaction piston (5) and an external cross section of the reaction piston (5).

Abstract: In a brake-pressure producing device of the present invention, a power piston 10 of a hydraulic booster 2 comprises a stepped piston including a large-diameter portion 10a on which fluid pressure of a power chamber 30 is exerted and a small-diameter portion 10b having the same diameter as the master cylinder piston 53. Both the pistons 10, 53 are interlocked with each other through an aligning rod 62. The pressurized fluid of the power chamber 30 is introduced into an annular chamber 51 formed on the circumference of the small-diameter portion 10b and the fluid pressure of the pressurized fluid is exerted on a stepped portion 10c between the large-diameter portion 10a and the small-diameter portion 10b in the direction opposite to the direction of the fluid pressure of the power chamber 30.

Abstract: The hydraulic system for a servo steering of a motor vehicle, incorporates a main valve mechanism producing the assistance pressure (Pa) applied to a hydraulic assistance device (12) and including a pair of parallel fluid circuits between a source (14) of pressurized fluid and a reservoir (16), each fluid circuit comprising at least two restrictions (1,2,1',2') capable of being modulated by a rotor mechanism (10) cooperating with a stator mechanism (11), the junction point of the restrictions of each circuit being connected to a respective chamber of the hydraulic assistance device (12) and a secondary valve mechanism producing the reaction pressure (Pr) applied to the steering wheel shaft and including a second pair of parallel fluid circuits between a source (24) of pressurized fluid and a reservoir (16), each of the fluid circuits comprising at least two restrictions (3,4,3',4') capable of being modulated by the rotor mechanism (10) cooperating with stator means, the rotor mechanism (11) cooperating with t

Abstract: Pressure gain compensation for a single-stage servovalve of the jet pipe type. The pressure gain compensation is provided by a separate reciprocally mounted spool having a feedback wire connected between the spool and the ejector jet. The spool has a differential pressure applied across the ends thereof from the receptors disposed opposed the ejector jet. Movement of the spool applies a force feedback to the ejector jet which is proportional to the pressure differential across the receptors and is opposite the force applied to the ejector by the torque motor to thereby compensate for pressure gain.

Abstract: A vehicle steering for turning the steerable wheels of a vehicle having a fluid motor with a housing defining a fluid chamber and a piston in the chamber dividing the chamber into first and second chamber portions. A rotatable steering input member is supported by the housing. A rotatable follow-up member is associated with the piston and rotatable upon movement of the piston in the chamber. A valve controls pressurized fluid flow to the first and second chamber portions. The valve comprises first and second relatively movable valve parts. One of the valve parts is connected with the input member and the other of the valve parts is connected with the follow-up member forming a unit therewith. The unit has a surface against which fluid pressure in the first and second chamber portions acts tending to create an axial force on the unit. Pressure is applied to another surface area of the unit to balance the axial force acting on the unit.

Abstract: A hydraulic booster includes a power piston which is inserted slidably into a cylinder member and has a tip portion which is coupled to a piston of a master cylinder, a pressure chamber disposed in the rear of the power piston, a return valve provided in such a manner as to open and close a channel for connecting the pressure chamber to a reservoir, and a supply valve disposed in such a manner as to connect the pressure chamber to a high-pressure fluid source, a high-pressure fluid being introduced into the pressure chamber as the return valve is closed and the supply valve is opened. A valve sleeve is slidably inserted in the power piston and is urged rearwardly of the power piston by a spring, and a cam portion provided in the valve sleeve is employed to open and close the supply valve.

Abstract: There is disclosed a hydraulic reaction mechanism which is easy to manufacture and for use with an automotive power steering system. The mechanism has an input shaft and an output shaft which are rotatable relative to each other and mounted in a housing. A servovalve is mounted between the shafts and actuated in response to the relative movement between the shafts. Radially protruding portions are formed at the end of the input shaft that is on the side of the output shaft. The output shaft has an enlarged portion provided with cylinder holes in which reaction pistons are received. The pistons hydraulically push both sides of the radially protruding portions. The pistons have grooves in which retaining plates for restricting rearward movement of the pistons are engaged.

Abstract: A liquid pressure booster as may be used in a brake booster or clutch booster produces an oil pressure of a level which corresponds to the magnitude of an input applied to an input shaft. The oil pressure acts upon a power piston, which then produces an amplified output in response to a small input. The oil pressure is also returned to act upon the input shaft so as to provide a reaction to the input. The invention provides a step in at least one of the input shaft and the power piston so that the combination of the step and the housing defines a pressure chamber having a pressure responsive surface at the step. A flow path switching valve selectively establishes a communication of the pressure chamber with either the power chamber or a reservoir. When the switching valve is operated, the pressure responsive area of the input shaft which is acted upon by the oil pressure can be changed, thereby changing the magnitude of the reaction transmitted to a driver.

Abstract: A compact power steering device is provided wherein the power steering valving is actuated by axial movement of a pinion having helical teeth engaging a rack in a steering housing. The valving utilizes head and seat valves with valve heads and coacting valve seats which are actuated on axes parallel to the pinion axis within the housing and requiring no more than the overall distance occupied by axial movement of the pinion as effected by rotation of a steering wheel during steering. Opposed springs effect a centered position for the pinion in neutral position of the valving for straight ahead steering. Thus, a centering spring is dominant and limited in movement to fix the valving as biased by other springs to a precise neutral position.

Abstract: A power-assist device for an automotive steering system employs spool valves of substantially identical construction and identical size to control the fluid pressure in smaller and larger area chambers of an unbalanced cylinder. For compensating difference of effective area between smaller and larger area chambers, the position of bores defned in a housing of a pressure control valve for receiving the spool valves are differed from each other so that the spool valve opening and closing an induction path for the smaller area chamber and opening closing a drain path for the larger area chamber moves at greater magnitude than that of the other spool valve which opens and closes an induction path for the larger area chamber and opens and closes an exhaust path for the smaller area chamber.

Abstract: The distributor (10, 11), typically with a star-type rotor in a discoid stator, incorporates a valve means with an OR logic function (5, 5') of preselection of the direction of the reaction (22, 23) to be applied to the input component as a function of the relative displacement between the primary and secondary components of the distributor, formed in one piece with the distributor and consisting of pairs of edges cooperating between two cavities (39a, 39b) of the stator (28, 30) and a cavity (44) of the rotor (31) advantageously formed in a reaction arm (41) of this rotor and permanently communicating with the source of pressure (14) of the distributor via a restriction (4) which can be externally modulated. The restrictions (5, 5') providing the OR logic function come into operation first, before the actual distribution restrictions (1, 2, 3; 1', 2', 3') of the distributor supplying the assistance actuator (19).

Abstract: An improvement in a known power steering system of the type in which movement of a steering wheel is transmitted via a torsion bar to an oil path switching valve to actuate a power cylinder in a desired steering direction by switching a high pressure oil path extending from an oil pump to the oil path switching valve and a low pressure oil path extending from the oil path switching valve to an oil tank. A part of the working oil flowing through the high pressure oil path is led to a reaction piston to restrain torsion of the torsion bar.

Abstract: A speed limiting hydraulic slide valve. The slide valve is provided with control pressure chambers at each end thereof. The slide is provided with a longitudinal passage at each end and this passage opens into the adjacent control pressure chamber. Each passage is normally closed by a check valve. Each longitudinal passage communicates with a peripheral passage on the valve of the slide by means of a radial passage. If the hydraulic actuator, such as a cylinder, begins to move too rapidly, the pressure in the radial passage will drop, and the pressure in the appropriate control pressure chamber will thereupon overcome the check valve in the passage which opens into such chamber, and this will cause the valve slide to move in a direction which will decelerate the action of the cylinder.

Abstract: The distributor, embodying two mutually displaceable primary (35) and secondary (38, 43) members, includes a reaction device (37, 39, 40) operated by externally modulated reaction pressures, the reaction device having opposite inlets connected to independent circuits (22, 23) extending from corresponding outlets of valve means having OR logic function (24) actuated by the primary member of the distributor (21) in a phase lead with respect to the internal valve means (1, 2; 1', 2') of the distributor.

Abstract: An auxiliary fluid power steering device having a servomotor (8) and a control valve (13) in a common steering gear housing (1). In order to relieve the control valve of axial pressure forces, the valve body (14) of the control valve has four surfaces (24, 25, 26, 27) of equal area respectively exposed exclusively to fluid in the inlet port (22), in the outlet port (23), in one of the servomotor pressure chambers (9) adjacent the control valve and in the other pressure chamber (10) of the servomotor.

Abstract: A booster steering servomotor having a piston is pressurized and exhausted by a valve having a rotary valve plug within a valve sleeve and coacting flow control grooves wherein means for centering the rotary valve plug and steering mechanism of the vehicle wheels is effected by hydraulic power after a steering operation. Accordingly, little or no resort to axle geometry is required for such purpose thereby saving the energy normally utilized in the steering operation. Such energy expenditure has been necessary to put wheel restoring force in the axle geometry, e.g., due to inclination of king pins. In essence, the components effect rotation of the rotary valve plug during steering return in a direction to pressurize the servomotor pressure chamber which has been previously non-pressurized to bring the steering linkages back to straight ahead steering.

Abstract: A control apparatus for a power-assisted steering system, comprising a power cylinder having pressure acting chambers respectively communicating with the control ports of a pressure control valve having inlet and outlet ports respectively communicable with the delivery and suction ports of a pump, and first and second flow control valves each having an inlet port and a discharge port communicating with the suction port of the pump, each flow control valve including a control pressure acting chamber communicating with a pressure acting chamber of the power cylinder to develop a differential pressure variable with a differential pressure between the pressure acting chambers of the cylinder, and a valve member movable in response to the differential pressure acting thereon and urged to provide communication between the inlet and discharge ports of each flow control valve, the inlet port of the first flow control valve being in constant communication with the delivery port of the pump and the inlet port of the pr

Abstract: A servo valve for a power steering booster comprises a power piston and cylinder assembly including a power piston reciprocatively movable therewithin and a spool assembly including a hollow spool for controlling selective supply and discharge of hydraulic pressures onto and from both sides of the power piston, a pair of reaction pistons slidably fitted within ends of the hollow spool to form a reaction hydraulic chamber therewithin, a reaction spring interposed between the reaction pistons, cover plates closing the ends of the hollow spool, through which a steering input transmission shaft passes, and reaction support pins of bearing rollers made with a high dimensional accuracy held in guide holes formed in the cover plates between the respective reaction pistons and partitions located at ends of a housing slidably accommodating the spool assembly and having ports for the selective supply and discharge of hydraulic pressures, thereby eliminating the high accuracy machining of parts associated with the spool

Abstract: A booster having a vacuum powered booster section and a hydraulic powered booster section which are normally actuated together to supply boosted force to a master cylinder. When the air valve of the vacuum booster section is operated to cause atmospheric air to enter the variable pressure chamber of the vacuum booster, it also engages and moves the hydraulic booster control valve to restrict hydraulic fluid flow therethrough, causing the hydraulic booster section control valve to be actuated to create a hydraulic pressure differential across the power wall of the hydraulic booster section. Both booster sections deliver boosted force through the output member of the hydraulic booster section to the master cylinder. Either booster section is operable when for any reason there is no power available for actuation of the other booster section.

Abstract: A hydraulic brake booster of the type utilizing pressurized fluid supplied to a hydraulic power steering device, wherein a flow regulating valve is adapted to rapidly increase the pressure in a power chamber of the booster in response to actuation of the booster and another flow regulating valve is adapted to ensure supply of the pressurized fluid to the power steering device, and wherein an accumulator is adapted to surely operate the booster even when pressure supply to the power chamber from the fluid pressure source is accidentally blocked or stopped.

Abstract: A vehicle steering system wherein a manual steering gear output controls actuation of a linear hydraulic motor. A control valve, which distributes fluid to and from the boost cylinder, is disposed between the pitman shaft and pitman arm of the manual steering gear. Rotation of the pitman shaft, in response to operator input, causes rotation of the control valve which directs fluid pressure to the hydraulic motor to provide steering assist. The fluid pressure is also directed, through the control valve, to selectively operate on hydraulic reaction members so that a force proportional to steering effort is transmitted back to the operator. A mechanical "overcenter feel" is also provided and has incorporated therewith a mechanical override to provide full manual steering when there is not sufficient fluid pressure to provide hydraulic assist for steering.

Abstract: A control valve for hydraulic servo-steering systems embodying connections for a pressure-source, a discharge and a servo-steering motor provided with a valve member, with the valve member being connected with one section of a divided steering shaft or spindle, in which one or a plurality of adjustable control pistons or reaction pistons are arranged preferably transverse and off-center to the axis of the valve member, and are activated by an activator device rotatable through a small angle relative to the valve member, and connected with the other section of the steering spindle, the activator means being positioned with one part of its length in or on the valve member, whereby the valve member is rotatably and axially immovably positioned in a generally affixed connection body, or in a sleeve connected therewith, in a manner so that the supply and release of a pressure medium into or out of the valve member, independent of the relative position of the connection body and valve member to each other, is guara

Abstract: A rotary type hydraulic servo-mechanism constructed with a hollow-cylindrical casing, an input shaft extending through the casing, a driven output member slidably mounted on the casing, a servo-valve mechanism formed in the surface of the input shaft which slides on the driven output member, a hydraulic fluid chamber to generate a resisting torque against rotational force of the input shaft, and a passage to connect this hydraulic fluid chamber with the servo-valve mechanism, and hydraulic drive chambers defined by a space between the inner wall of the hollow cylindrical casing and the outer periphery of the driven output member.