Abstract: A modular control apparatus for actuating hydraulic valve systems includes an actuating section including a tilting control member and a plurality of control rods provided with a pusher, which interacts with the control member so as to translate the control rods in the longitudinal direction, a sensor section including a plurality of sensor members suitable to detect a movement in the longitudinal direction of said control rods and a blocking section comprising a blocking device that is capable of individually blocking in the longitudinal direction each of said control rods. The actuating section can be alternately connected to the blocking section or to the sensor section so that the sensor section can be directly connected to the actuating section, detecting the longitudinal movement of the control rods also if the blocking section is not present.

Abstract: A positioner (102) for controlling a fluid operated actuator (101) including a first fluid chamber (109) and a second fluid chamber (110) is provided. The positioner (102) comprises a first fluid conduit (105) coupled to the first fluid chamber (109). The positioner (102) also comprises a second fluid conduit (106) coupled to the second fluid chamber (110). A differential pressure controller (240) provided in the positioner (102) is adapted to control a fluid supply to the first and second fluid conduits (105, 106) based on a differential pressure between the first and second fluid chamber (109, 110).

Abstract: A pneumatic brake system that includes at least one pneumatic latching valve; a single device, such as a solenoid, for providing momentary pilot signals to pneumatic latching valve; a source of pressurized supply air in communication with the pneumatic latching valve; a spring brake or other pneumatic device in communication with the pneumatic latching valve; and, optionally, an indicator device for monitoring and displaying the state of the pneumatic latching valve. Upon receiving a first momentary pilot signal the pneumatic latching valve changes from closed to open and delivers pressurized air to the spring brake. Upon receiving a second momentary pilot signal, the pneumatic latching valve changes from open to closed and exhausts pressurized air from the spring brake to the external environment. The valve remains “latched” in its current state until the signaling device is energized and the next momentary pilot signal is received.

Abstract: An efficient use of discharged energy of a boom cylinder is provided. A control unit has a function of receiving an output signal from a sensor provided in a boom operated valve and determining a manipulated direction and a manipulated variable of the boom operated valve, and a function of, in accordance with the manipulated direction and the manipulated variable, controlling the degree of opening of a proportional solenoid valve and operating the tilt-angle control units to control the tilt angles of a sub pump and an assist motor. An output of the assist motor is used to assist in an output of the sub pump and an output of the electric motor.

Abstract: An air conditioning system includes a heat source unit, an air supply device that supplies the outside air to the room as the ventilation air, a water supply type humidifier for humidifying the ventilation air, a heating medium circuit, and a supply water heating device. The heat source unit heats a heating medium that is used for heating the room in a heating medium—refrigerant heat exchanger. The heating medium circuit includes at least one room heating device that releases the heat of the heating medium heated in the heating medium—refrigerant heat exchanger into the room, and circulates the heating medium between the room heating device and the heating medium—refrigerant heat exchanger. The supply water heating device uses the heat generated from the heat source unit in order to heat water to be used in the humidifier.

Abstract: In a brake hydraulic pressure generating device in which the brake operating force is applied to a pressure adjusting valve through a stroke simulator and the hydraulic pressure supplied from the hydraulic pressure source is adjusted to a value corresponding to the brake operating force, during return of the brakes, the return stroke before the brake hydraulic pressure begins to drop is large, so that the brake feeling is bad. This invention proposes a solution to this problem. Hysteresis is imparted to the stroke simulator so that the output hydraulic pressure of the pressure adjusting valve for the stroke of the simulator piston stroke during increase of the brake operating force will be higher than that during reduction of the brake operating force by setting the sliding resistance of the simulator piston greater than that of the input piston.

Abstract: The invention provides a method and apparatus wherein the apparatus includes a housing having a first end and a second end. The housing also includes a first aperture and a second aperture. The first aperture is positioned to communicate with a first fluid source at a first pressure. The second aperture is positioned to communicate with a second fluid source at a second pressure. The first pressure is greater than the second pressure. The apparatus also includes a first piston disposed in the housing. The first piston is moveable between the first and second ends. The first piston includes a front surface communicating with the second aperture and a back surface communicating with the first aperture. The first piston also includes a first passageway communicating with the front and back surfaces. The apparatus also includes a three-way valve fluidly disposed between the first aperture and the back surface and between the front surface and the back surface.

Abstract: A hydraulic pressure control device is provided which is capable of pressure reduction and pressure increase by electronic control without changing over hydraulic circuits, and which is reliable and simple in structure. A vehicle brake device using such a control device is also provided. A pressure chamber and an offset spring are provided in a hydraulic pressure control valve. A spool valve is moved to a position corresponding to brake operating force, thereby changing over connections between the output port and the discharge port and between the output port and the input port, and adjusting the degrees of opening of valve portions. In this manner, the hydraulic pressure at the output port to a value corresponding to the brake operating force is controlled.

Abstract: An apparatus for providing feedback to an operator relative to a force applied to a system is disclosed. The apparatus has a first magnet and a second magnet. The first magnet receives a signal indicative of the force applied to the system and generates a first magnetic field in response to the signal. The second magnet is disposed adjacent the first magnet and generates a second magnetic field that interacts with the first magnetic field to generate a magnetic force. An operator interface is operatively engaged with one of the first magnet and the second magnet such that the magnetic force acts on the operator interface.

Abstract: An apparatus for providing feedback to an operator relative to a force applied to a system is disclosed. The apparatus has a first magnet and a second magnet. The first magnet receives a signal indicative of the force applied to the system and generates a first magnetic field in response to the signal. The second magnet is disposed adjacent the first magnet and generates a second magnetic field that interacts with the first magnetic field to generate a magnetic force. An operator interface is operatively engaged with one of the first magnet and the second magnet such that the magnetic force acts on the operator interface.

Abstract: An apparatus for translating the movements of a portion of an operators anatomy residing in communication with an input fitment into hydraulic signals thereby directing the motion of a machine member moved by a hydraulic driver with natural motion of the operator. The subject apparatus also transfers the motion of the machine member under control to a proportional motion of the control fitment, giving the operator a tactile sense of the direction and magnitude of the motion being executed by the machine member under the control of the apparatus. Additionally, the subject apparatus conveys a force proportional to that experienced as a resistance to movement by a machine member under the control of the apparatus to the operator through the control fitment, giving the operator a tactile sense of the resistance opposing the machine operation being directed by the operator.

Abstract: A brake system including a negative pressure booster, a master cylinder of tandem type and an intensifying arrangement. The intensifying arrangement defines an intensifying chamber disposed rearward of a primary piston, a pump for supplying a braking liquid to the intensifying chamber, and a reaction piston and a sleeve for controlling the pressure of the braking liquid which is supplied to the intensifying chamber. As a brake pedal is depressed and the intensifying arrangement is actuated, a sum of an urging force from the negative pressure booster and an urging force from the intensifying arrangement operates the primary piston to develop a master cylinder pressure. The sum is proportional to the input or a force depressing the brake pedal.

Abstract: A brake reaction which occurs as a brake booster is actuated is prevented from being transmitted to a brake pedal, and instead pseudoction reaction imparting means 41 is provided to transmit a pseudo-reaction to the brake pedal. A valve body 5 and a power piston 3 are capable of relative movement in the axial direction, and are normally urged away from each other by a spring 8. The valve body 5 is normally urged forward by a spring 42 which is disposed within the variable pressure chamber B. This arrangement allows a variation in the advancing stroke of the brake pedal to be suppressed small if a variation occurs in the magnitude of a negative pressure which is introduced into a constant pressure chamber A as the brake booster is actuated, thus providing an improved brake feeling experienced by a driver.

Abstract: A brake booster which permits an axial relative movement between a power piston and a valve body is disclosed. An arrangement is made which prevents a brake reaction from being transmitted to a brake pedal. As an alternative therefor, pseudo-reaction imparting means transmits a pseudo-reaction to a brake pedal. A rear end of the valve body is covered by a tubular cover and bellows connected thereto, and its internal space is maintained in communication with a constant pressure chamber. The bellows has an effective diameter which is chosen to be of an equal size to the diameters of a vacuum valve seat and an atmosphere valve seat. This allows a pseudo-reaction and a brake pedal stroke to be obtained which depend on the force with which a brake pedal is depressed if a negative pressure within the constant pressure chamber varies, thus imparting a better brake feeling to a driver.

Abstract: A control apparatus for a brake system having a housing with a first bore for retaining a spool valve and a second bore for retaining a selector valve. A cap separates the first bore into a first chamber and a second chamber. The first chamber has an inlet port connected to a source of fluid under pressure, a gear port for connected the source of fluid under pressure to a hydraulically operated device, a relief port connected to a reservoir and an outlet passage connected to a selector valve which communicates pressurized fluid through an outlet port to a brake booster. The second chamber is connected to the reservoir and the second bore. The a spool valve has a peripheral surface with first and second grooves separated by lands and an internal operational passage connecting the second groove to the outlet passage.

Abstract: A pneumatic brake booster comprising two working chambers, with each working chamber communicating a respective one of two reaction chambers. A divider dividing the reaction chambers provides a pressure feedback force to an input shaft. A selective valve (13) allows communication (C2) provided between the rear working chamber and the front reaction chamber to be closed, at least partially, when an airflow from the rear working chamber towards the front reaction chamber is higher than a predetermined amount. This allows the response time of the booster is adjusted.

Abstract: According to the invention, the booster is not provided with a brake reaction transmission mechanism, and hence a reaction cannot be transmitted to a brake pedal. On the other hand, a pseudo-reaction imparting means is provided to impart a pseudo-reaction of suitable magnitude which depends on the degree of depression of the brake pedal. The pseudo-reaction imparting means is arranged so that when the brake pedal is depressed relatively rapidly, a relatively smaller braking reaction is imparted than during a usual depression. With this arrangement, the transmission of an abnormally high braking reaction to a driver which is experienced in a conventional booster during a quick braking operation due to an operational rag of the booster is avoided.

Abstract: The invention provides a valve arrangement for controlling the brake pressure in a hydraulic power-brake system. By actuating a brake valve, a brake pressure proportional to the actuation force builds up in an outlet pressure chamber, with a first ball-seat valve. By displacing an actuation piston from its normal open position in which the outlet pressure chamber is connected to a relief chamber which is continuously kept free of pressure, the first ball-seat valve can be adjusted into a blocking position. After the first ball-seat valve has closed, further axial displacement of the actuation piston, (out of its normal blocking position, in which an inlet pressure chamber which is subjected to the high outlet pressure of a pressure accumulator is blocked off with respect to the outlet pressure chamber) moves a second ball-seat valve into its open position.

Abstract: A brake system for use in connection with a vehicle including a hydraulic internally boosted master cylinder, a hydraulic pump, and hydraulic brakes wherein the master cylinder controls hydraulic fluid pressure to the brakes and has a primary or sensing piston, a modulator stem, and a secondary pistons, with the sensing piston responsive to a mechanical input force to urge the secondary piston forwards increasing the hydraulic fluid pressure applied to the brakes. In a second embodiment, the internally boosted master cylinder further includes a tertiary piston movable by hydraulic pressure between retracted and extended positions and biased toward the retracted position by a tertiary piston return spring. The tertiary piston controls hydraulic pressure applied to one or more brakes independent of the brakes controlled by the secondary piston.

Abstract: A brake system with a hydraulic pilot brake valve for use in connection with a vehicle requiring finite brake control with high volume pressure control. The brake system includes the hydraulic pilot brake valve, a main hydraulic system, a control hydraulic system, and hydraulic brakes. The main hydraulic system includes a belt-driven hydraulic pump, a tank of hydraulic fluid, and an accumulator. The control hydraulic system includes an electrically actuated hydraulic pump and a tank of hydraulic fluid. The pilot brake valve is designed to control the flow of hydraulic fluid from the main hydraulic system to the hydraulic brakes, and includes a modulator chamber and a primary chamber. The modulator chamber houses a modulator piston valve, and the primary chamber houses a primary input piston which extends into a sleeve chamber of a sleeve. The modulator piston valve controls a modulating fluid flow from the control hydraulic system to generate amplified input forces on the input piston in the primary chamber.

Abstract: A brake apply control system for a vehicle. The control system has a selectively operable mechanical brake apply portion and a selectively operable hydraulic brake apply portion. The mechanical brake apply portion includes an operator linkage for connecting the operator with a mechanical brake apply mechanism and a hydraulic piston and valve combination for providing a hydraulic feedback force to the operator. The hydraulic brake apply portion includes a source of hydraulic pressure, a brake apply valve for supplying a selective brake signal of variable intensity in response to operator input, a conduit system which connects the source of hydraulic pressure to the hydraulic piston and valve combination and which communicates the brake signal to the hydraulic piston and valve combination.

Abstract: A valve control system for controlling the operation of a pressure fluid-activated device such as a hydraulic cylinder includes a valve housing having an internal, sealed valve chamber therein. A valve spool is slidably disposed for lengthwise movement within the valve chamber, the valve spool having a valve member for selectively admitting a pressure fluid through passages in the vale housing. A movable handle for manual operation of the valve is connected to the valve spool by a connecting mechanism, whereby movement of the handle causes lengthwise movement of the valve spool relative to the valve housing. A neutral-centering tactile feedback mechanism applies a return force to the handle when the handle is in an operative position. The return force varies in proportion to the pressure of the pressure fluid within the valve, which pressure actuates the device. The feedback mechanism ceases to apply the return force when the handle returns to a neutral position.

Abstract: Spool valve for fluid systems, the valve having a slidable spool in a bore in a valve block having three ports spaced aially along the bore for control of fluid flow, the spool having three spaced O-ring seals to correspond with the ports and having a reduced diameter portion between two of the O-ring seals, and a pressure-equalizing conduit connecting one end of the spool with the outlet port of the valve. Small lands of substantially equal diameter to the spool adjacent the reduced diameter portion before the two O-ring seals provides restricted or throttled fluid flow prior to increased fluid flow via reduced diameter portion.

Abstract: The invention relates to a rotary hydraulic distributor comprising a primary rotary element (3) coupled to an actuating device and connected for rotation with a valve rotor, a secondary rotary element (5) coupled to a driven device and connected for rotation with a valve stator, the valve stator and the valve rotor mutually cooperating to control a double acting servomotor of the driven device, a limited relative angular displacement being permitted between primary and secondary elements (3, 5) on either side from a central rest position, and a reaction mechanism being provided in order to bias the primary element (3) toward the central rest position. According to the invention, the reaction mechanism consists of a pair of independent substantially U-shaped pistons (7) able to tilt within respectively one bore (12) of a pair of bores symmetrically provided in secondary element (5), the legs (15) of U-shaped pistons (7) engaging and biasing opposite radial ends (4) of primary rotary element (3).

Abstract: A steering reaction force generating mechanism for generating a reaction force acting on an input shaft is provided within a cylindrical space of a housing between a lower end portion of the input shaft and an upper end portion of a pinion shaft (output shaft). The steering reaction force generating mechanism includes an input shaft accommodating section for accommodating the lower end of the input shaft together with its two control arms which protrude symmetrically and radially therefrom. A pair of reaction force chambers are provided at both sides of the input shaft accommodating section in parallel with the two control arms. Two pairs of through bores are formed respectively between one of the reaction force chambers and the input shaft accommodating section, and between the other of the reaction force chambers and the input shaft accommodating section.

Abstract: A port control member is depressed by either a mechanical force applied on it by the pilot, for moving it to meter pressure and flow from a supply pressure to the wheel brakes, or a hydraulic pressure force applied following take-off, to actuate the brakes for stopping the wheels from spinning. The valve housing defines an annular pressure chamber surrounding a portion of the port control member. The port control member includes a feedback passageway between the pressure chamber and a feedback chamber formed between the inner end of the port control member and the valve housing. The port control member is also surrounded by a sleeve which has an inner surface extending radially outwardly from the inner end of the port control member. The feedback passageway, which can include a damping orifice, produces a feedback force to the pilot which is increased when the sleeve is jammed with respect to the port control member.

Abstract: A hydraulic power steering apparatus having a hydraulic cylinder as a source for generating a force assisting a steering force, and comprising a directional control valve which switches the feeding direction of pressured oil to the hydraulic cylinder, and a constraining device which constrains its switching operation responsive to the vehicle speed, characterized in that an oil pressure control valve for controlling oil pressure fed to the directional control valve and constraining device is controlled by pressure of a vehicle speed sensor pump which develops oil pressure corresponding to the vehicle speed, and in that a sudden change of a constraining force caused by external disturbance signals such as electromagnetic waves is prevented and the constraining force corresponding to the vehicle speed can be obtained, by introducing oil pressure, which becomes higher or lower responsive to changes of the vehicle speed, into the constraining device to generate the constraining force responsive to the oil pressur

Abstract: An improved hydrostatic steering mechanism is disclosed having a rotary valve with a radially displaced resilient feedback mechanism.

Abstract: This invention provides a steering system of a fully hydraulically operated type for use in particular in construction vehicles and industrial vehicles and so forth with enhanced stability in operating a steering wheel when the vehicle is running at high speeds without impairing the operability of the steering wheel when the vehicle is running at low speeds. This steering system is provided with an apparatus for regulating the actuating force applied by an actuating shaft connected with a steering wheel by the action of the fluid pressure force to be controlled in accordance with the running speed of the vehicle. Thus, the steering force obtained by the steering gear of the present invention is increased in proportion to the increase in the vehicle speed.

Abstract: An improved hydrostatic steering mechanism is disclosed having a rotary valve with a radially displaced resilient feedback mechanism.

Abstract: In a servosteering arrangement, a control mechanism combines a pressure operated valve responsive to servomotor chamber pressure, and a solenoid and plunger responsive to speed of the vehicle by means of a proportional magnet solenoid for controlling reaction chamber pressure and thus the manual force required to be exerted by a driver for steering a vehicle. Thus, a variable throttle pressure responsive valve combined with a speed responsive solenoid responsive inversely to speed, controls the manual steering force necessary to effect steering at various speeds, particularly in tright curves at low speeds with high servomotor pressures. An important safety feature in the event of failure of solenoid current is the maintenance of openness of the pressure operated valve with consequent high resistance to steering.

Abstract: A power steering system which includes a fluid source that supplies pressure fluid of a constant flow rate, a fluid motor for supplementing manual steering torque, a servo-valve for distributing fluid to the fluid motor, and a reaction device for applying hydraulic reaction or feeling to a steering wheel. A magnetic control valve is connected to the reaction device to control fluid pressure applied thereto in accordance with a vehicle operating condition, such a vehicle speed. A flow dividing valve serves to divide the pressure fluid of a constant flow rate in a predetermined ratio into first and second flows which are respectively directed to the servo-valve and reaction device. A bypass conduit provided with a bypass orifice is connected between the fluid source and the servo-valve in parallel relation with the flow dividing valve.

Abstract: A power steering system for use in a motor has a pair of reactive pressure chambers in which the opposite ends of a valve spool are exposed, one of the reactive pressure chambers communicating with one fluid-pressure chamber in a reciprocable fluid-pressure cylinder assembly through a first orifice, the other reactive pressure chamber communicating with both fluid-pressure chambers in the cylinder assembly through second and third orifices, respectively. The first, second and third orifices are the first and second orifices are defined in the valve spool. A third passage define by a space between the spool and the valve cylinder communicates the first and third orifices.

Abstract: The invention relates to a steering force controller for power steering apparatus which controls a steering force by controlling an oil pressure supplied to an oil pressure reaction chamber of a reaction mechanism. A pressure controlling mechanism which controls the oil pressure supplied to the oil pressure reaction chamber operates to increase a channel area between a reaction passage which communicates with the oil pressure reaction chamber and a feed passage which communicates with the discharge port of a pump and at the same time reduce a channel area between the reaction passage and a discharge passage which communicates with a tank associated with the pump in accordance with a displacement of the spool in one direction which is caused by a solenoid. In this manner, the flexibility in controlling the pressure within the reaction chamber is enhanced. Chambers formed at the opposite ends of the spool valve communicate with the tank and are maintained under a low pressure.

Abstract: A power steering system including an input shaft coupled to a steering wheel, a torsion bar for transmitting rotation of the input shaft to an output shaft, a power cylinder coupled to the output shaft, an oil path switching valve for switching oil paths to the power cylinder in accordance with the difference of turning angle between the input shaft and the output shaft, a high pressure oil path for supplying working oil delivered from an oil pump to the power cylinder via the oil path switching valve, a low pressure oil path for returning the working oil from the power cylinder to an oil tank via the oil path switching valve, a reaction piston for exerting a restraining force between the input shaft and the output shaft to limit the difference of turning angle therebetween, a control oil path extending from the midway of the high pressure oil path to the reaction piston, a pressure control valve for controlling oil pressure in the control oil path extending to the reaction piston to a level not higher than a

Abstract: A steering force control apparatus for a power steering apparatus of a vehicle of the type having a reaction chamber responsive to fluid pressure applied thereto for producing a reaction force to counteract the steering force produced by a power cylinder. A main tubular spool is disposed in a valve case movably relative to the valve case and has an inner valve surface. A sub-spool is disposed in the main spool movably relative to the main spool and has an outer valve surface cooperative with the inner valve surface to define a variable throttle for selectively connecting a fluid pump to the reaction chamber and to the power cylinder according to the movement of the sub-spool relative to the main spool in response to the vehicle speed. The main spool is moved relative to the valve case and the sub-spool in response to the fluid pressure applied to the reaction chamber when the fluid pressure is above a certain value to enable the variable throttle to disconnect the fluid pump from the reaction chamber.

Abstract: A power steering system is hydraulically operated to decrease the manual steering force in response to the steering wheel angular displacement. A main pump supplies a first hydraulic fluid to the power steering system to operate the same. The main pump is hydraulically coupled to the power steering system so that the pressure of the first hydraulic fluid is affected by the operation of the power steering system and therefore is indicative of the steering wheel angular displacement. A reaction chamber receives a second hydraulic fluid from a subpump and is hydraulically operated to increase the steering force in proportion to the pressure of the second hydraulic fluid.

Abstract: There is disclosed a hydraulically operated power steering system which comprises a reciprocating-type hydraulically operated cylinder unit for moving a steering link mechanism and having first and second chambers, a reservoir containing hydraulic fluid therein, a hydraulic pump feeding the hydraulic fluid in the reservoir to the cylinder unit, a control valve unit including a line coupled to communicate the hydraulic pump, a line coupled to communicate the reservoir, a valve cylinder having passages coupled between the first and second chambers to provide fluid communication therebetween, and a valve spool slidably arranged in the valve cylinder and reciprocatingly movable in response to rotation of an input shaft, the cylinder unit including therein right and left reaction chambers to which opposite ends of the valve spool are exposed, the reaction chambers being communicated with the respective first and second hydraulic chambers through orifices, and a valve for dividing the left reaction chamber into a r

Abstract: A working fluid passage supplying a fixed flow rate is divided into passages so that a flow rate ratio between the two passages is varied by a variable orifice valve based on a detection signal of a physical quantity factor which varies depending on travelling and steering conditions of the vehicle. The working fluid from one of the two passages is supplied to a steering assisting force generating mechanism through a changeover valve which changes over the passages in accordance with a direction of steering torque acting on the input shaft steering the vehicle, to generate the steering assisting force. The working fluid from the other passage is supplied to a steering reaction force generating mechanism through the changeover valve, and by generating the steering reaction force to the input shaft, the steering force is controlled to an adequate condition corresponding to the physical quantity factor.

Abstract: A power steering system for positioning the steerable wheels of a vehicle that provides increased handling feedback to the operator via the steering wheel. The system uses a motor driven pump and a bidirectional hand pump to supply and control fluid pressure for steering the wheels. Two pairs of servomotors steer the vehicle with a first pair receiving a regulating amount of fluid from the bidirectional hand pump and a second pair primarily receiving fluid pressure for moving the steerable wheels from the motor driven pump. In order to increase read ability during selected steering manuevers and change the steering ratio, a compensating valve decreases fluid pressure from the power pump to the second pair of servomotors in response to an operator controlled condition such as turning angle or vehicle speed. The system can also be arranged to have a maximum ratio which will facilitate steering in the absence of fluid pressure from the motor driven pump.

Abstract: In a brake valve of the type in which a given ratio is maintained between a master pressure developed by a brake pedal and an actual brake pressure, an arrangement is provided for continuous, rather than stepwise, adjustment of this ratio. The brake valve includes a control piston which is subjected to the master pressure and which, by the displacement thereof, opens and closes connecting channels between an accumulator containing a primary pressure fluid and a brake, as well as between the brake and a fluid collecting tank. The control piston and a measurement piston apply counter forces to the arms of a balance beam whose lever ratio determines the degree of feedback of the instantaneous brake pressure to the control piston. A stop is provided in the path of the axis of the control piston, which limits the stroke of the piston, to prevent the overloading of the balance beam during abnormally high braking pressures such as occur, for instance, during panic braking.

Abstract: A power steering system which includes a fluid source that supplies pressure fluid of a constant flow rate, a fluid motor for supplementing manual steering torque, a servo-valve for distributing fluid to the fluid motor, and a reaction device for applying hydraulic reaction or feeling to a steering wheel. A magnetic pressure control valve is connected to the reaction device to control fluid pressure applied thereto in accordance with a vehicle operating condition, such a vehicle speed. A flow dividing valve serves to divide the pressure fluid of a constant flow rate in a predetermined ratio into first and second flows which are respectively directed to the servo-valve and reaction device. The predetermined ratio is varied such that the flow rate of the fluid supplied to the reaction device increases as the pressure of the fluid supplied to the fluid motor increases.

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: The distributor (10), typically with a star-shaped rotor in a discoid stator, comprises a reaction device (11) advantageously integrated in the distributor and providing the actuating member (17) of the distributor with a reaction opposite to the actuating torque exerted on this actuating member and proportional to the power-assistance force supplied by a jack (12) controlled by the distributor (10). A regulating valve (30, 31) is associated with the reaction device (11), being typically located upstream of the latter, and is put into effect when the reaction force applied by the reaction device reaches a maximum predetermined value, in order to limit the reaction force to this predetermined value.

Abstract: In a handle steering force control mechanism adapted to stabilize steering feeling of a steering handle by imparting hydraulic reaction to a power steering device when the vehicle is travelling at high speed, a hydraulic control apparatus for supplying stabilized pressure oil to the power steering device and a hydraulic reaction chamber. This hydraulic control apparatus comprises a main spool and a sub-spool slidably inserted into the main spool to form a variable throttle whose open area is varied by relative displacement therebetween. This variable throttle, when the vehicle travels at high speed, closes the main valve side by the sub-spool and opens the hydraulic reaction side to increase reaction pressure. When reaction pressure reaches a predetermined value in response to steering pressure, the main spool is displaced by pressure oil to cut the reaction pressure.

Abstract: A power steering apparatus which includes an input member rotatably mounted in a valve housing, an output member rotatably and axially slidably mounted in a gear housing integral with the valve housing and arranged coaxially with the input member, a valve rotor integral with the input member, a valve sleeve rotatably mounted in the valve housing and arranged in surrounding relationship with the valve rotor, the valve sleeve being connected integrally with the output member to cooperate with the valve rotor for selectively directing fluid under pressure to opposite ends of a hydraulic power cylinder in response to relative rotation between the input and output members, a cam follower element positioned between the inner ends of the input and output members for permitting relative rotation between the input and output members, and a pressure mechanism arranged to apply fluid under pressure responsive to the vehicle speed to the outer end of the output member for increasing the resistance to relative rotation of

Abstract: Simulated steering resistance is provided for the rotative valving control of a booster steering servomotor by providing the manually rotated section of the valving control which connects to a steering wheel with a coaxial reaction piston having faces exposed to operating pressures of the respective chambers of a double ended servomotor. The reaction piston is helically geared on the manually rotated section and restrained by a sliding keyway against rotation relative the valving control section conventionally connected by a torque rod to the manually rotated section. During steering, operating pressure on one face or the other of the reaction piston will cause it to shift and thereby effect a torque force on the manually rotated section due to the helical gearing which force opposes the manual steering force to thus simulate steering resistance.

Abstract: Disclosed is a device for controlling the pressure of a fluid supplied to a power steering apparatus in response to the speed of a vehicle. The device is arranged such that in a fluid return passage from the power steering apparatus to a pump, there is provided a throttle valve controlled by the speed of the vehicle, so that the controlled oil pressure is guided to an oil pressure reaction chamber in the power steering apparatus.

Abstract: A supply pressure control device for an air clutch providing a valve for controlling a pressure of compressed air supplied to the air clutch, providing a pneumatic feed-back mechanism giving an air clutch supply pressure to said valve in the direction of reducing pressure, providing a control spring elastically urging said valve in the direction of increasing pressure against the pneumatic feed-back mechanism, providing a spring bearing changing an urging force of the control spring, interconnecting the spring bearing to a clutch pedal in order to actuate the spring bearing in the direction of weakening the urging force of the control spring when the clutch pedal is stepped on, and providing a stepping force loading mechanism withstanding the stepping-on of the clutch pedal.

Abstract: A booster steering valve control of the kind that comprises a pair of valve pistons reciprocal in a rotative valve body are driven by a fork shaped member at the end of a steering spindle. The fork shaped member comprises a pair of spaced actuator pins which engage in openings of the respective valve pistons. Thus, the valve body and the fork shaped member have a common axis about which the actuator pins rotate. A particular construction of the invention resides in the displacement of the actuator pins such that their axes are not in a common plane with the steering spindle axis but offset so that the surfaces of engagement between the actuator pins with the respective valve pistons and the spindle axis are coplanar. Engagement is maintained by spring bias acting on the valve pistons.