Abstract: In a hydraulic power steering apparatus, hydraulic pressure for generating steering assist power is varied by varying opening of a variable throttle portion by movement of a spool. The spool is disposed in a provisional origin by driving a stepping motor in one direction according to a number of steps for setting provisional origin from a position at a time of start of control, and the number of steps at a time of completing of the driving is set to a provisional origin for calculation. In a return to origin permission state where the spool is disposed in a provisional origin and the number of steps from the provisional origin for calculation is zero, a number of steps at a time when the driving of the stepping motor according to a number of steps obtained by subtracting the number of steps for setting provisional origin from a number of steps for setting origin is completed is set to an origin for calculation, and the movement of the spool is stopped at the origin with a stopper.

Abstract: A hydraulic auxiliary power steering for motor vehicles having a source for a hydraulic medium, in particular an oil pump, which can be driven during operation by a drive device, in particular by an internal combustion engine of the vehicle or by an electric motor, having a steering transmission and having a line system for the hydraulic medium connecting the source to the steering transmission, wherein the line system has at least two line sections through which the hydraulic medium can flow.

Abstract: A steering system includes a fluid actuator, a first steering circuit in selective fluid communication with the fluid actuator, and a second steering circuit in selective fluid communication with the fluid actuator and disposed in parallel to the first steering circuit. The second steering circuit includes a load-reaction feature and an isolation valve with the isolation valve being adapted to enable and disable the load-reaction feature.

Abstract: In a power steering device employing a hydraulic power cylinder, a motor-driven pump, and a driving power source for the motor, a power steering control system is configured to electrically connected to at least the motor and the power source for controlling a driving state of the motor and a power source voltage of the power source. The power steering control system includes a motor control circuit that generates a motor driving signal, whose command signal value is determined based on a steering assist force applied through the power cylinder to steered road wheels, a booster circuit that boosts the power source voltage, a motor angular acceleration detection circuit that detects or estimates a motor angular acceleration, and a booster-circuit control circuit that controls, responsively to the motor angular acceleration, switching between operating and non-operating states of the booster circuit.

Abstract: There is provided a power steering system including an electric motor for generating a steering force in response to an command value, and a controller for generating the command value to the electric motor. Here, the controller generates the command value in correspondence with steering state of wheels, thereby controlling torque or rotation number of the electric motor.

Abstract: A method of controlling a magneto-rheological power steering coupling is provided. The method is to be employed by a controller and is initiated upon engine start-up. The method includes initializing calibration parameters and reading a plurality of input values. Subsequently, a hand wheel angle rate value is calculated from one of said plurality of input values. A pump speed command value is calculated as a function of at least the hand wheel angle rate value. A pump speed error value is then calculated, and a proportional-integral-derivative calculation is performed acting on the pump speed error value to determine a pulse width modulation duty cycle value. The duty cycle value is then output to a power driver to provide a control signal to the magneto-rheological power steering coupling. Also provided is control system and apparatus operable to perform the functions described hereinabove.

Abstract: A piston is disclosed that includes a longitudinal passage disposed between outlets on the opposing faces of the piston, and a radial passage extending from a node with the longitudinal passage to an outlet on the annular wall between opposing piston seals. Check valves are disposed in the longitudinal passage between the node and each of the piston faces, such that each of the check valves enables fluid flow from its inlet to the outlet on the annular wall, and block fluid flow from the outlet on the annular wall to the inlet. In the event of pistons in a fluid system becoming out of phase with each other, fluid may be admitted through the inlet of the longitudinal passage and the respective check valve and out a side wall outlet, thereby bypassing the piston to exit via the respective end port, until another, out-of-phase piston or pistons in the system also reach full extension or retraction, automatically returning all pistons in the system to be in phase with each other.

Abstract: In a hydraulic power cylinder equipped power steering apparatus, a part of each of first and second hydraulic lines, associated with respective hydraulic chambers of the power cylinder, is constructed by a low-rigidity line functioning as a variable volume hydraulic-line section and formed of an elastically-deformable, flexible tube, made of a synthetic rubber. The line length of the low-rigidity line, which is disposed in each of the first and second hydraulic lines, is dimensioned so that each of an apparent modulus Ke of volume elasticity of working fluid in a first hydraulic pressure transmission path and an apparent modulus Ke of volume elasticity of working fluid in a second hydraulic pressure transmission path is set within a specified apparent volume modulus range, defined by an inequality 100 MPa?Ke?300 MPa.

Abstract: A power steering apparatus (10) includes a first pump (24) which is continuously driven to supply fluid under pressure to a power steering motor assembly (18). A second pump (32) is driven by the engine (30) of the vehicle when a predetermined vehicle operating condition occurs. The predetermined vehicle operating condition may, if desired, be operation of the engine (30) of a vehicle at a speed which is less than a predetermined speed. A flow control valve (40) directs fluid flow from the first and second pumps to the power steering motor assembly (18) during operation of both pumps. A diverter valve (62) directs fluid from the first pump (24) along a fluid flow path which is spaced from the flow control valve (40) during operation of only the first pump. The first pump (24) may, if desired, be smaller than the second pump (32).

Abstract: A fluid system is described, which comprises first and second cylinders, each of which comprises a piston, and a first end and a second end corresponding to full stroke positions of the corresponding piston. The first ends and second ends of the two cylinders thereby define four cylinder ends. The first and second cylinders are fluidly coupled to each other via a first matched pair of cylinder ends selected from the first ends or the second ends. The system includes first and second bypass devices. The bypass devices are each configured so that when a full stroke position is occupied at a respective bypass end from among the four cylinder ends by the corresponding piston, the respective bypass device opens an outlet that allows a flow from the respective cylinder to bypass to a conduit coupled to the respective bypass end. This allows for the two cylinders to self-correct any tendency to lose synchronization with each other, and allows the system to balance pressure between the two cylinders.

Abstract: An electrically actuated, hydraulic power steering system is provided. The steering system includes a hydraulic pump for generating hydraulic pressure, a hydraulic fluid reservoir, a hydraulic cylinder, and a control valve arrangement that selectively connects the hydraulic cylinder to the pump and the hydraulic fluid reservoir. The control valve arrangement is characterized during the on-center position by a first and a second chamber of the hydraulic cylinder being in fluid communication with each other but not with the fluid reservoir. In one embodiment, the steering system has a steering sensor, a control box, and two pressure accumulators for providing at least two levels of steering assist.

Abstract: A method for endforming a tubular member for use assembly for a hydraulic system comprises (1) a connector member having an inner surface exhibiting a stepped configuration and a fixing member at the distal end thereof, and (2) an endform tubular member having an outer surface corresponding to the inner surface of the connector member, wherein the endform tubular member mates with inner surface of the connector member to provide an endform tubular assembly having an improved design for conveying fluids in a hydraulic system. The endform tubular assembly has inherent features therein that are measured to provide quantified values for assessing the robustness of the assembly and predict the performance of such assembly in high pressure applications for prolonged periods of time.

Abstract: The invention provides a method and a system for moving an element, e.g. a rudder of a ship or a wheel of a vehicle. The element is moved by a hydraulic fluid. According to the invention, an operator indicates a desired movement, and in accordance with the desired movement, at fluid is provided from at least three fluid providers each providing a share of the fluid in parallel streams and only considering the desired movement not the shares provided by the other fluid providers. The invention allows continuation of a steering task even if one fluid provider is disabled, and the invention allows the continuation even without having to notice that one provider is disabled. Accordingly, the invention provides an improvement and simplification relative to the known hydraulic steering systems.

Abstract: A hydraulic traction system for vehicles is described. The system comprises a hydraulic vane motor mounted at each wheel of the vehicle, and equal number of identical hydraulic vane motors operated as engine driven pumps, and a control system for regulating the flow and direction of hydraulic oil during operation. The hydraulic motor is of a novel design that has a hollow non-drive shaft that accepts incoming hydraulic oil, this allows internal components of the hydraulic motor to be arranged in such a way to improve the efficiency of the hydraulic traction system.

Abstract: A center-closed power steering system provides power steering assistance in engine-off conditions for reduced fuel consumption. The power steering system includes a hydraulic pump mechanically driven by the engine, a high pressure accumulator, a steering gearbox fluidly connected to the accumulator, and a center closed valve mechanically connected to a driver-operated steering wheel. The valve is configured to selectively control flow of pressurized fluid from the accumulator to the steering gearbox to provide power steering assistance. The inner shaft of the rotary center-closed valve is provided with a cavity with V-shaped notches on the transition surfaces on lands configured to sealingly engage the inner surface of the valve outer sleeve, in order to provide a smooth transition in flow for power steering assistance, and a better driver feel.

Abstract: A vehicular hydraulic system having a hydraulic pump, an optional flow-splitting valve, a first hydraulic application, a pressure reducing valve and a second hydraulic application arranged in series along a primary flow path. When the pressure in the primary flow path between the pump and first application is elevated to a first threshold value, the flow-splitting valve, if present, splits the fluid discharged by the pump into a first fluid flow communicated to the primary flow path upstream of the first application and a second fluid flow communicated to the primary flow path between the first application and the pressure-reducing valve. The pressure reducing valve limits the maximum pressure of the fluid discharged therefrom to a second threshold value wherein the first threshold value is greater than the second threshold value. The first and second hydraulic applications may take the form of a brake booster and a steering gear, respectively.

Abstract: The invention provides an electric power steering apparatus which can improve a steering feeling. In the electric power steering apparatus, in the case that once the electric abnormality is generated in the hardware such as the motor, the torque sensor or the like and an output of the assist force by the motor is reduced, however, the electric abnormality is thereafter dissolved due to some kind or another reason, the output of the assist force by the motor is increased immediately to an intermediate target value (within a broken line ?). Accordingly, it is possible to prevent such a steering feeling as the steering wheel becomes suddenly heavy.

Abstract: The method provides hydraulic pressure for mechanical work from an engine lubricating system in an internal combustion engine by supplying oil to an engine lubrication gallery for lubricating the engine and to at least one variable oil demand accessory. Each of the variable oil demand accessories has an individual pressure regulator. The output of the variable displacement pump is regulated based on the sum of fluid flow required by the engine lubricating system and the engine accessories, regardless of the engine output. The demand for fluid is determined by the individual pressure regulators on each of the engine accessories. In a preferred embodiment, an accumulator stores high-pressure fluid to be used to power the hydraulic accessories.

Abstract: A hydraulic steering apparatus with steering amount amplification is provided, wherein a metering device for supplying pressure medium to steering cylinders is actuated in accordance with an amount of rotation of the steering wheel. With the aid of a control block it is possible to deliver an additional pressure medium volume to the steering cylinders, wherein control of the control block is effected through the intermediary of a control circuit containing an effective control pressure that is substantially lower than the load pressure for transmitting the steering moment at the steering cylinder. A spring assembly for the control block is also provided, wherein two springs are arranged in parallel, one of which only takes effect following a predetermined stroke of the control element.

Abstract: In an electrical power steering apparatus, steering shaft reaction torque is estimated by a steering shaft reaction torque estimation unit, and a reference road reaction torque is estimated by a reference road reaction torque estimation unit. The estimated steering shaft reaction torque and the reference road reaction torque are weighted, and, in response, a target steering reaction torque is set by a target steering reaction torque generation unit, hysteresis width and slope of the target steering reaction torque are respectively adjusted, and steering feeling is thereby easily improved.

Abstract: The flow control device comprises a supply passage (2) for supplying hydraulic fluid discharged by a pump (1) to a power steering output section (8); a variable throttle section (3) situated at an intermediate position of the supply passage (2); and a flow control valve (4) for returning the hydraulic fluid in the supply passage (2) to the pump inlet side, in accordance with a pressure differential between upstream and downstream of the variable throttle section (3). When the pump (1) is halted, the flow control valve (4) is impelled by a spring (13) and closes the variable throttle section (3). A throttle passage (51) is provided for connecting the upstream side and the downstream side of the variable throttle section with the supply passage (2).

Abstract: An engine driven pump 24 is connected with a power steering motor assembly 18. An electric motor 36 drives a pump 34 connected with the power steering motor assembly 18. A control apparatus 38, 44, 52, 62 and 72 effects operation of the electric motor 36 to drive the pump 34 when the power steering motor assembly 18 requires fluid in addition to fluid supplied by the engine driven pump 24.

Abstract: A power steering system includes first and second drain passages connected to the first and second passages, respectively, and first and second passage switching valves arranged at connections of the first and second drain passages and the first and second passages, respectively. When a hydraulic pump operates to discharge the hydraulic pressure to the first passage, the first passage switching valve provides fluid communication between pump-side and cylinder-side portions of the first passage and closes off the first drain passage. And when the hydraulic pump stops, the first switching valve provides fluid communication between the cylinder-side portion of the first passage and the first drain passage.

Abstract: An all terrain vehicle has a frame carried by a group of wheels. At least one of the wheels is steerably connected to the frame. A steering handle assembly is rotatably connected to the frame. A servo valve has an input shaft connected to the steering handle assembly and an output shaft connected to a pitman arm. A linkage extends from the pitman arm to the steerable wheel or wheels. A pump draws fluid from a reservoir and passes the fluid through the servo valve before the fluid is returned to the reservoir. The servo valve redirects at least a portion of the flow to a cylinder to drive a ram within the cylinder in response to steering movement of the steering handle assembly. The ram, in turn, provides a power assist to the steerable wheel or wheels. A variable speed, constant displacement pump can be used to vary the flow rate in a manner that reduces the flow rate as the vehicle speed increases. Alternatively, a bypass can be used to vary a flow rate through the servo valve.

Abstract: A power steering system and a method of charging the power steering system with hydraulic fluid are provided. Hydraulic fluid is selectively supplied to hydraulic chambers of a power cylinder via oil passages from a reversible pump, according to a steering torque. In addition, a bypass passage is provided between oil passages. A normally open switching valve is provided in the bypass passage. When the system is assembled, the hydraulic fluid is supplied from an oil reservoir via the switching valve or the reversible pump, and circulated in the hydraulic circuit. The air in the hydraulic circuit is discharged via the switching valve.

Abstract: An integrated hydraulic control system includes a steering control unit and a priority flow divider integrated into a unitary casing. An interface fluidly couples the casing for the steering control unit and priority flow divider directly to a control valve casing. All hydraulic communication between the steering control unit, the priority flow divider, and the control valve are located inside the casings.

Abstract: A system and method of controlling flow outlet from a hydraulic pump. The system provides the level of flow required to execute the driver's steering commands. This method of control reduces the average torque requirement of the hydraulic pump thereby improving fuel economy by unloading the vehicle's accessory drive, while also providing the variable assist power steering feature. The Fuel Efficient Power Steering (FEPS) control algorithm is an optimal method of regulating flow by actuating the electronic flow control device in the pump assembly. This electronic flow control device allows an increase in hydraulic fluid flow to the steering gear in order to increase the provided assist and to reduce hydraulic fluid flow to the steering gear to improve fuel economy, if no additional assist is needed. The calculation of the desired flow control device current is primarily based on vehicle speed and steering wheel rate.

Abstract: A power steering system includes: a first drain passage for draining an oil pressure from a first oil passage, a second drain passage for draining the oil pressure from a second oil passage, and a pair of a first and second switch valves. When one of the first oil passage and the second oil passage is so pressurized by an operation of a reversible oil pump as to have an increased internal pressure, the pair of the first switch valve and the second switch valve allow the following: i) closing one of the first drain passage and the second drain passage which one is connected to the oil passage having the thus increased internal pressure, while ii) opening the other of the first drain passage and the second drain passage which other is connected to the oil passage that is so depressurized as to have a decreased internal pressure.

Abstract: Operates steering angular velocity in first steering angular velocity calculating unit and second steering angular velocity calculating unit, by using steering angle signal from steering angle generating unit, and outputs steering angular velocity by switching them with reference to a certain threshold value of steering angular velocity.

Abstract: A power steering system includes a rotary slide valve which has a housing, an input shaft and an output shaft which can be rotated relative to each other to a limited extent. A centering piston is provided which is non-rotatably and axially movably connected with the input shaft and delimits a pressure space in the housing. The rotary slide valve further comprises a centering ring which is non-rotatably connected with the output shaft, and arm inlet to the pressure chamber. The pressure chamber has a controlled outlet. There is also proposed a method of operating such a power steering system.

Abstract: The invention relates to a device and a method to ensure the steerability of an industrial truck that has a hydraulic steering system. The invention includes at least one gas generation cartridge (8) and a device (16) to activate the generation of the gas. The invention teaches that energy is available in an emergency for the hydraulic circuit of a hydraulic steering system. On the side of the gas generation cartridge (8), when there is a need to supply energy to the hydraulic circuit, pressure is increased which can then be transmitted to the hydraulic medium. The invention makes available an advantageous emergency power supply system for a hydraulic steering system of an industrial truck.

Abstract: A system and method to allow a paving machine to form tight radii in continuous extrusions such as curbs and gutters is disclosed. A shift cylinder is used with the steering mechanism of a typical paving machine to allow sharp radius turns. The steering cylinder is used to pivot the track of the paving machine about its leg and the steering cylinder is used to pivot the leg relative to the frame of the paving machine. A hydraulic circuit is operator activated to allow fluid flow through a flow divider to ensure each cylinder operates in concert.

Abstract: A method of providing hydraulic pressure for mechanical work from an engine lubricating system in an internal combustion engine by supplying oil to an engine lubrication gallery for lubricating the engine and at least one variable oil demand accessory. Each of the variable oil demand accessories have individual pressure regulators. The output of the variable displacement pump is regulated to the sum of fluid flow required by the engine lubricating system and the demand for fluid generated by the individual pressure regulators on each of the engine accessories, regardless of the engine output.

Abstract: A power steering system for a vehicle, comprises a steering shaft connected to a steering mechanism. A hydraulic power cylinder is provided for assisting a steering effort of the steering mechanism. A reversible pump is provided having first and second discharge ports which are respectively connected through first and second hydraulic lines with two hydraulic pressure chambers of the hydraulic power cylinder so that the two hydraulic pressure chambers are respectively provided with hydraulic pressures. A driving device is provided for driving the reversible pump to rightly and reversely rotate. A differential pressure regulating valve is disposed in the hydraulic circuit to maintain pressure at least in the first and second hydraulic lines at a level of atmospheric pressure or higher in an inoperative condition of the reversible pump.

Abstract: A first fluid passage extends from a first outlet/inlet port of a hydraulic pump to a first work chamber of a power cylinder, and a second fluid passage extends from a second outlet/inlet port of the pump to a second work chamber of the power cylinder. A switch system switches the role of the first and second outlet/inlet ports in accordance with a turning direction of a steering wheel. Flow control mechanisms are respectively incorporated with the first and second fluid passages, so that a controlled flow of hydraulic fluid from the hydraulic pump to the first or second work chamber and vice versa are appropriately carried out thereby providing the driver with a comfortable steering feeling. A bypass arrangement may be provided between the first and second fluid passages to deal with a residual pressure that would be remained in the first or second work chamber when the hydraulic pump is under inoperative condition.

Abstract: A power steering system includes: a first drain passage for draining an oil pressure from a first oil passage, a second drain passage for draining the oil pressure from a second oil passage, and a pair of a first and second switch valves. When one of the first oil passage and the second oil passage is so pressurized by an operation of a reversible oil pump as to have an increased internal pressure, the pair of the first switch valve and the second switch valve allow the following: i) closing one of the first drain passage and the second drain passage which one is connected to the oil passage having the thus increased internal pressure, while ii) opening the other of the first drain passage and the second drain passage which other is connected to the oil passage that is so depressurized as to have a decreased internal pressure.

Abstract: The invention relates to a hydraulically supported steering system with a steering gear, which is driven by a hydraulic piston/cylinder unit. The steering system includes a piston. The piston is axially displaced in a cylinder and divides the cylinder into two cylinder chambers. Each cylinder chamber is connected to a separate hydraulic line that serves both as pressure supply line and as return line. The hydraulic lines are also connected to a servo valve. A throttle mechanism, which features a variable flow resistance in at least one flow direction is arranged in at least one hydraulic line. The flow of hydraulic fluid through the self-regulating throttle mechanism determines the flow resistance in this flow direction, namely a higher flow resistance will occur at low flow and lower flow resistance at high flow.

Abstract: A power steering system includes first and second drain passages connected to the first and second passages, respectively, and first and second passage switching valves arranged at connections of the first and second drain passages and the first and second passages, respectively. When a hydraulic pump operates to discharge the hydraulic pressure to the first passage, the first passage switching valve provides fluid communication between pump-side and cylinder-side portions of the first passage and closes off the first drain passage. And when the hydraulic pump stops, the first switching valve provides fluid communication between the cylinder-side portion of the first passage and the first drain passage.

Abstract: A power steering system includes: a first drain passage for draining an oil pressure from a first oil passage, a second drain passage for draining the oil pressure from a second oil passage, and a pair of a first and second switch valves. When one of the first oil passage and the second oil passage is so pressurized by an operation of a reversible oil pump as to have an increased internal pressure, the pair of the first switch valve and the second switch valve allow the following: i) closing one of the first drain passage and the second drain passage which one is connected to the oil passage having the thus increased internal pressure, while ii) opening the other of the first drain passage and the second drain passage which other is connected to the oil passage that is so depressurized as to have a decreased internal pressure.

Abstract: To provide a power steering device capable of increasing the degree of freedom in the layout of the various elements, stabilizing the surface of the oil and preventing air from being included or mixing foreign materials with the oil in the oil tank. The power steering device includes a power assist cylinder arranged between a steering shaft and a chassis frame. A control valve is operated by the steering shaft to control the power assist cylinder. An oil pump pressurizes operating oil supplied to the power assist cylinder. Furthermore, an oil tank stores the operating oil, wherein the oil tank is of a closed type and integrally arranged in the oil pump.

Abstract: A steering system and a method for steering a vehicle, that has a wheel steering and an articulated steering. The steering system (1) has a steering unit (2), a first steering motor arrangement (7), which acts upon steered wheels, a second steering motor arrangement (8), which acts upon a converting kit, and a selection valve (6), which connects the steering unit (2) with either the first steering motor arrangement (7) or the second steering motor arrangement (8) in such a way that a steering will activate either the wheel steering or the articulated steering.

Abstract: A power steering system for a vehicle, comprises a steering shaft connected to a steering mechanism. A hydraulic power cylinder is provided for assisting a steering effort of the steering mechanism. A reversible pump is provided having first and second discharge ports which are respectively connected through first and second hydraulic lines with two hydraulic pressure chambers of the hydraulic power cylinder so that the two hydraulic pressure chambers are respectively provided with hydraulic pressures. A driving device is provided for driving the reversible pump to rightly and reversely rotate. A differential pressure regulating valve is disposed in the hydraulic circuit to maintain pressure at least in the first and second hydraulic lines at a level of atmospheric pressure or higher in an inoperative condition of the reversible pump.

Abstract: A hydraulic steering system (1) for a vehicle with two steering motor arrangements, particularly an articulated vehicle with wheel steering, with a hydraulic steering unit (2) having a measuring motor section (22, 23), with a selection valve (6), which connects an outlet (L, R) of the steering unit (2) with either a first steering motor arrangement (7) that preferably acts upon steered wheels, or a second steering motor arrangement (9) that preferably acts upon a converting kit, and which is hydraulically operable via a pilot valve (14), and with a pump (4), which is connected with the steering unit (2) and the pilot valve (14). This permits the vehicle to be steerable in connection with an emergency.

Abstract: A hydraulic power steering system for use in a vehicle to eliminate energy waste when power assist is not required is disclosed. The hydraulic power steering system includes a pulley powered by a crankshaft in the vehicle, a clutch operably connected to the pulley, a hydraulic pump operably connected to the clutch, and controlling means for engaging and disengaging the clutch with the pulley and the hydraulic pump to provide hydraulic power to the system. It also includes a hydraulic accumulator to provide system pressure for short periods before the pump clutch can engage in response to a steering input.

Abstract: A hydraulic steering arrangement with a steering handwheel which is connected with a hydraulic steering unit, and with a steering motor connected with a pump via a steering valve. In a steering arrangement of this kind, a simple construction is desired, though under maintenance of the required security. For this purpose, the steering valve can optionally be operated by a steering handwheel or by a hydraulic pressure generated by a control pressure generator.

Abstract: A power steering system is provided which comprises a bypass conduit connecting between first and second communication conduits and having bypass conduit ports. A pair of valves disposed in the bypass conduit for selectively opening and closing the bypass conduit ports in response to the pressure fluid from the pressure source. The valves are adapted to provide communication between the first and second communication conduits when the hydraulic pressure source is inoperative.

Abstract: A hydraulic power steering system includes a steering gear having a cylinder, and a piston slidably disposed in the cylinder to divide the cylinder into first and second cavities on opposed sides of the piston. A pair of turn tubes are coupled to the cylinder for connecting the cylinder cavities to a source of hydraulic fluid. An open fluid leakage path extends between the cylinder cavities or between the turn tubes. This open leakage path is sized to damp fluid pressure fluctuations and thereby reduce fluid-induced shudder in the steering system. The open fluid leakage path may comprise a valve or a passage extending between the turn tubes, a passage in the piston or in the seal between the piston and the gear housing cylinder, or a passage in a banjo block connected across the turn tube inputs to the gear housing.

Abstract: A dual counterbalance valve is added in the hydraulic lines between the steering unit and the steering cylinders on an implement to maintain pressure in the steering lines by metering hydraulic fluid to and from the cylinders under pressure so that the steered wheels stay in phase. Since the steering system is kept under constant pressure, the wheels can only be steered by the steering unit and not by tractive soil forces so toe in and toe out problems are eliminated without need for a mechanical tie rod connecting the steered wheels. The valve is added in-line to the system so that current machines can be easily retrofitted.

Abstract: The invention relates to a locking mechanism (1) for electromechanical protection of the hydraulic circuit of mechanically driven vessels/boats and vehicles, mostly trucks, but also private cars can be equipped with it, in which the steering gear and/or braking system can be blocked, in which a core cylinder (13) of the roughly 3/2-valve constructed locking mechanism (1) is operated by electronic control, in which in the driving position the mentioned core cylinder (13) is locked or blocked, in which the locking mechanism with accompanying electronic control (9) is mounted in a closed steel housing underneath the bonnet, which is also secured by the system and in which also an encoder unit (4) for further protection is provided, through which an optimally secure locking mechanism (1) against theft is created.

Abstract: A hydraulic power steering apparatus 1 which is arranged so that a damper valve 10 is disposed in hydraulic oil circuits 8 and 9 for connecting an oil passage selector valve 11 in a gear box with right and left oil chambers of a power cylinder 6. The damper valve 10 comprises a spool valve. And a control oil chamber 21 of the spool valve 10 is connected with a hydraulic oil feed passage 18 for connecting a hydraulic pump 13 which is driven by an internal combustion engine so as to discharge hydraulic oil, with the oil passage selector valve 11. Its back pressure chamber 17 is connected with a hydraulic oil circulating passage 19 for connecting the oil passage selector valve 11 with a reservoir tank 12. Orifices 27 and 28 are provided in connecting oil passages 22 and 20, such that when discharge oil pressure of the hydraulic pump 13 rises, opening of the spool valve 10 increase.