Linde Aktiengesellschaft

Horst Deininger

Eckehart Schulze

Gustav Kleineisel

Alfred Langen

Franz H Forster

Walter Kropp

Rudolf Richter

Wolfgang Grone

Binio Binev

Burkhard Stuermer

A valve system is provided for the hydraulic work system of a work vehicle, in particular of an industrial truck, with a elevating drive system for raising and lowering a load and a tilting drive system, each of which can be actuated by a control valve, in particular by an electrically actuated control valve, the opening width of which determines the speed of movement of the user. The elevating drive system is realized in the form of a single-action hydraulic cylinder and a check valve in the form of a seat valve that can be opened toward the hydraulic cylinder is located in a hydraulic line leading from the control valve to the hydraulic cylinder. The tilting drive system is realized in the form of a double-action hydraulic cylinder. The valve system has an improved function with low energy losses.

Control valve system for the hydraulic work system of a work vehicle

A hydrostatic axial piston machine employs a swash plate construction in which the diagonal position of the swash plate can be controlled by at least one positioning piston pressurized with a control pressure. A control valve is in a line which leads to at least one positioning piston. A simple electrical-hydraulic control of the swash plate can be accomplished by the electrical actuation of the control valve. The control valve may be in the form of a rotary disk valve which can be actuated by a stepper motor.

Hydrostatic axial piston machine with electro-hydraulic swash plate control

A control valve device controls the movement of at least one hydraulic user. Relative movement of a control spool valve of a control valve with respect to a housing controls the connection of at least one hydraulic connection that is in communication with the user with a delivery connection and with a reservoir connection. The control spool valve can be moved relative to the housing by an actuator device. The housing has a multi-layer construction consisting of plates connected with one another by soldering or another adhesive, which plates comprise intermediate plates that are located between two end plates. The thickness (D) of the end plates is greater than the thickness (d) of the intermediate plates, whereby the end plates are provided with a fastening device for the actuator device and/or of connection devices for the hydraulic lines.

Control valve device

A hydrostatic drive system with an adjustable pump in the delivery flow has at least one consuming device connected to the pump. Associated with each consuming device are actuation devices that specify the direction of movement and the speed of movement. A control valve device controls the direction of movement and the speed of movement. The delivery flow of the pump can be adjusted to the hydraulic flow required by the actuated consuming devices. The hydrostatic drive system makes possible the operation of the consuming devices independently of the load and the operation of the consuming devices independently of the direction of the load, in a simple manner and with lower energy losses. Associated with each consuming device is a delivery flow sensor that measures the hydraulic flow discharged from the consuming device to a reservoir, and/or a delivery flow sensor that measures the hydraulic flow from a delivery line of the pump to the consuming device. Each delivery flow sensor is connected to an electronic control. The electronic control is connected to the actuation device, to the control valve device and to a delivery flow setting device of the pump. The electronic control controls the control valve device and/or the delivery flow setting device of the pump as a function of the direction of movement and the speed of movement specified at the actuation device and of the hydraulic flow discharged from the consuming device measured at the delivery flow sensor and/or the hydraulic flow admitted to the consuming device measured at the delivery flow sensor.

Hydrostatic drive system

A hydrostatic drive system with a pump and at least one consuming device that is connected to the pump can be actuated by a control valve. The control valve can be actuated as a function of an actuator that specifies a desired speed of movement and a direction of movement of the consuming device. The control valve in the center position, makes possible an unpressurized circulation of the pump. The control valve can be actuated electrically, and there is a sensor that measures the actual speed of movement of the consuming device. The control valve, the speed-of-movement sensor and the actuator are connected with an electronic control that controls the control valve as a function of the direction and speed of movement specified by the deflection of the actuator and of the actual speed of movement of the consuming device as measured by the speed-of-movement sensor. The speed-of-movement sensor may be a delivery flow sensor.

A control valve device for a hydraulic user includes an electrically actuated control valve that has a sliding spool for the control of the connection of at least one user channel that is in communication with the user with a delivery channel and a reservoir channel. A shutoff valve located in the user channel blocks a return flow from the user to the control valve. A pilot control valve actuates the shutoff valve. When the user channel is connected with the reservoir channel, the pilot control valve can be actuated to move the shutoff valve into the open position by an actuator element. The control valve device has a low actuation force for the deflection of the sliding spool and for the actuation of the pilot control valve. A gear train actuates the sliding spool and the actuator element. The gear train has an input element which is effectively connected with an electrical drive device and the output element which is in a driving connection with the sliding spool and is effectively connected with the actuator element. In one configuration, the output element is in connection by a connecting rod with the sliding spool and located on the output element is a cam disc which is connected by a rocker arm with the actuator element.

Control valve device for a hydraulic user

Hydrostatic axial piston machine

Hydrostatic unit for driving an industrial truck with a pump, a hydrostatic propulsion unit and additional users of hydraulic energy, wherein the pump is located on an axle body of a drive axle. A control valve for the pressurization of the propulsion unit and at least one control valve for the pressurization of an additional user are located on the axle body or at least partly integrating into the axle body. In one embodiment, the axle body is a control seat receptacle of the pump and at least one traction motor of the hydrostatic propulsion unit. The control valves can be actuated electrically or hydraulically.

Hydrostatic unit for driving an industrial truck

A hydrostatic drive system is provided for a vehicle, in particular an industrial truck, with a hydrostatic traction drive system (16), a hydraulic work system (13) and a hydraulic steering system (9). The invention provides a drive system that is compact and exhibits improved operating behavior during the change from traction operation to coasting operation. To supply the traction drive system (16), the hydraulic work system (13) and the steering system (9), there is a hydraulic pump (1) with an adjustable delivery volume that works in the open circuit, which pump (1) discharges into a delivery line (5), in which there is a traction drive control valve (19) for the pressurization of the traction drive system, which is connected to an outlet line (22) leading to a reservoir, and which can be connected to delivery lines (20a, 20b) leading to the traction drive system (16), whereby in both the delivery line (5) and in the outlet line (22) there are respective flow regulators (23, 24), each of which can be pressurized by the pressure upstream of the choke point of the traction drive control valve (19) in the closing direction, and by the pressure downstream of a throttle point of the traction drive control valve (19) and by a spring in the opening direction. In one embodiment of the invention, a delivery branch line (5a) branches off from the delivery line (5) upstream of the flow regulator (24) and can be brought into communication with the steering system (9) and the hydraulic work system (13).

Hydrostatic drive system for a vehicle

A hydrostatic drive system is provided for a vehicle, in particular an industrial truck having a hydrostatic traction drive system (16), a hydraulic work system (20) and a hydraulic steering system (8). The drive system is compact and the energy utilization in the drive system is improved by providing a hydraulic pump (1) with an adjustable delivery volume working in an open circuit to supply the traction drive system (16), the hydraulic work system (20) and the steering system (8). In one configuration of the invention, there is at least one traction drive control valve (23) in the delivery line (5b) of the pump (1), whereby upstream of the traction drive control valve (23) in the delivery line (5b) of the pump (1) there is a priority valve (18) for the hydraulic work system (20), and upstream of the priority valve (18) of the hydraulic work system (20) there is a priority valve (6) for the steering system (8). In one embodiment of the invention, a feed line (11) of a feeder device (15) can be connected to the delivery line (5a) between the priority valve (6) of the hydraulic steering system (8) and the priority valve (18) of the hydraulic work system (20).

A regulating device for a hydrostatic positive displacement unit, such as an axial piston machine employing the swash plate principle, includes a control valve which pressurizes a regulating piston which determines the stroke volume or the displacement volume of the positive displacement unit. An electric-hydraulic regulating device having a simple construction is provided with the control valve in the form of a slide valve which can be actuated electrically. In one configuration of the invention, the slide valve can be actuated by a stepper motor.

Regulating device for a hydrostatic positive displacement unit

A track-laying vehicle has two tracks, each with a hydrostatic drive unit, where at least one drive motor 1, 2 adjustable in working volume is provided in each drive unit and to which at least one pressure medium supply line 3, 4, 5, 6 connected to a hydrostatic pump leads and which has a working volume adjusting device 9, 11, 10, 12 that can be influenced by a signal dependent on the operating pressure. To avoid unintentional changes in direction of the track-laying vehicle in the case of different resistances to the tracks, it is proposed to connect the pressure medium supply lines 3, 4, 5, 6 of all the drive motors 1, 2 to a shuttle valve circuit 32, 33, 34 which determines the highest of the operating pressures of the hydrostatic drive unit and empties in a signal line 19 that is connected to the control elements of the working volume adjusting devices 9, 11, 10, 12 of all the drive motors 1, 2.

Hydrostatic travelling mechanism for track-laying vehicles

A hydrostatic transmission in a closed circuit which includes a hydraulic engine having a stroke-volume control device and a hydraulic pump connected to said hydraulic engine by two pressure lines. The stroke volume of the pump and/or the engine is regulated by the stroke-volume control device. The closed circuit includes a reversing valve which is connected to both pressure lines and is controlled by the prevailing pressures in the pressure lines. The reversing valve connects the pressure line carrying the lower pressure to a delivery valve and connects the pressure line carrying the higher pressure to a pressure-reducing valve so that the level of the control pressure in the stroke-volume control device is determined. A pressure-reducing valve is located in each pressure line and the pressure-reducing valves and the reversing valve are combined as a single combination valve.

Hydrostatic transmission

A control device for a variable displacement hydrostatic machine having a stroke-volume regulator which is responsive to an actuating pressure. The control device includes a booster pump. The delivery pressure of the machine is the actuating pressure unless the delivery pressure of the machine is insufficient in which case the actuating pressure is a feed pressure produced by the booster pump. The control device includes a plurality of delivery-pressure lines and a proportioning pressure regulator having an outlet pressure which is proportionally reduced relative to the intake pressure connected between each delivery-pressure line and the stroke-volume regulator.

Control device for a variable displacement hydrostatic machine

An electrohydraulic signal converter includes an armature which is movable in a magnetic field generated by field coils and is located between two inlet channel orifices that are provided with restrictors. Drain channels are connected downstream from the orifices and lead to a pressureless tank. The armature is connected to the orifices so that a pressure differential can be produced between the pair of inlet channels in the converter. In order to keep the loss of oil of the signal converter low, the orifices are closed when the armature is in its neutral or central position. When the armature is moved from its neutral position, the orifice away from the armature is opened and permits the flow of hydraulic oil from one inlet channel to a drain channel. The orifices are each formed by a borehole into which can be inserted a cylindrical projection on each front face of the armature.

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Horstein-Alzenau, Germany

Horst Deininger