Deere + Company

Marcus Bitter

Richard Tudor

Folker Beck

Helmut Schaefer

Hendrik Nordhoff

Andreas Remmelmann

Christian Brueser

Scott R Wiens

Michael Kühn

Reiner Hoffmann

Harm-Hendrik Lange

Karsten Oberst

Marlin Martin Onnen

Helmut Schäfer

David Price

Steffen Schlemmer

Heinz Peter Huth

The invention relates to an system for supplying a hydraulic circuit with hydraulic fluid. The system includes a working reservoir and an auxiliary reservoir connected to the working reservoir by a hydraulic line. An air pump has an inlet connected to a suction line that opens into a liquid-free portion of the auxiliary reservoir so that a negative pressure can be built up in the auxiliary reservoir relative to the atmospheric ambient pressure. The air pump inlet is also connected to a control line, which comprises a control opening which is covered by the hydraulic fluid in the working reservoir, at least before the air pump is started up.

Hydraulic circuit supply system

For controlling supply priorities, a hydraulic system includes several loads, a pump, and a tank. One load has a first-level supply priority, and optionally a second load has a second-level supply priority subordinate to the first level. A third load has a third-level supply priority subordinate to the second level. Each load can be connected to the pump by a separate supply line. The supply lines for the first and the optional second load are connected to the pump by a common load-pressure-controlled priority valve and the supply line for the third load is connected to the pump by an additional load-pressure-controlled priority valve. A first load-pressure line leading to the pump is connected to a load-pressure line of the third hydraulic load and to a second load-pressure line.

Hydraulic system

A hydraulic arrangement for braking a trailer comprises a brake line connected between a brake system of a trailer and a trailer brake valve. The trailer brake valve is activated via a first control-pressure line which extends between the brake line and the trailer brake valve and via a second control-pressure line which extends between the trailer brake valve and a control-pressure source and acts in opposition to the pressure imposed on the trailer brake valve by the first control-pressure line. An adjustable pressure-reducing means for controlling the control pressure in the second control-pressure line is arranged in the second control-pressure line. It is proposed to design the control-pressure source as part of a hydraulic control of a brake system of a traction vehicle drawing the trailer and to force the pressure-reducing means mechanically into an open basic position by means of an adjustable prestressing force.

Hydraulic braking arrangement for a trailer

A hydraulic system includes an engine driven adjustable hydraulic pump which supplies fluid to a hydraulic consumer, and an electronic control unit. The adjustable pump includes flow controller for controlling a pressure difference between the consumer and the adjustable pump to a pre-determined control pressure difference. The flow controller includes an actuator controlled by the control unit, through which the pressure difference can be controlled. The electronic control unit receives an engine speed signal and controls the actuator to control the pressure difference, in order to make power delivery of the adjustable pump conform to the operating conditions of a vehicle.

The invention relates to a hitch system for an agricultural vehicle for lifting and lowering a load or an attachment. The hitch system further includes a hydraulic system with a double-action hydraulic cylinder, and an electronic control unit connected to the hydraulic system for controlling the hydraulic system and the pressurization of the hydraulic cylinder. The control unit controls a contact pressure for a working device as a function of a sensed load on the axle.

Hitch system

A hydraulic arrangement for regulating a lifting mechanism () of an agricultural machine () is described. The hydraulic arrangement () comprises a hydraulic cylinder () having a chamber () capable of being acted upon by pressure, a proportionally adjustable inflow valve () which is connected on the outlet side via an inflow line () to the chamber () and which is connected on the inlet side to a hydraulic pump ('), a first outlet line () which makes a connection between the chamber () and a hydraulic tank (), adjustment means () for generating an adjustment signal for the hydraulic cylinder (), and an electronic control unit ().

Hydraulic arrangement

A hydraulic system for an agricultural vehicle is proposed. The hydraulic system comprises a main hydraulic circuit, which is fed with hydraulic fluid by a main hydraulic pump, a variable displacement charge pump which supplies charge pressure to the main hydraulic pump, and a lubricating hydraulic circuits. In order to keep efficiency losses on the vehicle to a minimum, particularly at high engine speeds, part of the hydraulic fluid delivered by the charge pump can be diverted to the lubricating hydraulic circuit.

A loader includes a hydraulically operated extension arm, a load sensor for monitoring the load condition on the loader and a hydraulic arrangement for actuation of the extension arm and/or an implement attached to the extension arm. The hydraulic arrangement exhibits at least one hydraulic cylinder with one supply line on the piston rod side and one supply line on the piston side. At least one mechanically switchable control device is coupled between a source of fluid pressure and a hydraulic tank, on the one hand, and the supply lines on the other hand. An electronic control unit is connected for effecting operation of a restricting device coupled between the supply lines in response to a load signal received from the load sensor so as to achieve a slowed-down actuation of the hydraulic cylinder in conjunction with the on set of a critical load condition. Thus, a restriction of a volumetric flow is achieved in at least one of the supply line on the piston rod side or the supply line on the piston side of the hydraulic cylinder.

Loader

A suspension system for an agricultural or construction industry vehicle is described. The suspension system comprises two hydraulic cylinders which support a frame in relation to an axle of the vehicle, the hydraulic cylinders being hydraulically connected to one another in a cross connection, so that a piston-side chamber of the one hydraulic cylinder is connected to the piston rod-side chamber of the other hydraulic cylinder and vice versa, in each case one hydraulic accumulator assigned to a hydraulic cylinder, a hydraulic source, a hydraulic tank, a control valve device, an electronic control unit, electrically switchable switch valves which are arranged in the cross connection between the hydraulic accumulators and the hydraulic cylinders, and a first and second supply line, which supply lines connect the control vale device to the cross connection. In order to prevent the activation of a suspension state in critical vehicle states, means for the detection and compensation of load states of the vehicle are provided in the suspension system.

Suspension system

A suspension system for an agricultural or construction industry vehicle is described. The suspension system comprises two hydraulic cylinders, which support a frame in relation to an axle of the vehicle, the hydraulic cylinders each having a piston-side chamber and a piston rod-side chamber and each of the chambers of the hydraulic cylinders being connectable to one another via connecting lines provided with a switch valve, a first supply line, which can be connected via a switch valve to the piston-side connecting line of the first hydraulic cylinder, a second supply line, which can be connected via a switch valve to the piston-side connecting line of the second hydraulic cylinder, a hydraulic accumulator, in each case connectable to the supply lines via proportionally adjustable orifices, a hydraulic source, a hydraulic tank, a control valve device, and an electronic control unit. In order to prevent the activation of a suspension state in critical vehicle states, means for the detection and compensation of load states of the vehicle are provided in the suspension system.

A loader includes a hydraulically operated extension arm, a load sensor for monitoring the load condition on the loader and a hydraulic arrangement for actuation of the extension arm and/or an implement attached to the extension arm. The hydraulic arrangement exhibits at least one hydraulic cylinder with one supply line on the piston rod side and one supply line on the piston side. At least one hydraulically switchable control device is coupled between a source of fluid pressure and a hydraulic tank, on the one hand, and the supply lines on the other hand. An actuating device is coupled for routing control pressure to the control device via first and second control pressure lines. An electronic control unit is connected for effecting operation of a control pressure control device, which is coupled to at least one of the control pressure lines, in response to a load signal received from the load sensor so as to actuate the control device for achieving a slowed-down actuation of the hydraulic cylinder in conjunction with the onset of a critical load condition. Thus, a restriction of a volumetric flow is achieved in at least one of the supply lines coupled to the hydraulic cylinder.

A hydraulic system for a suspension system is disclosed. The system has a hydraulic cylinder, a hydraulic tank, a conveying means, a hydraulic accumulator, a control device, a load holding device disposed between the hydraulic accumulator and the hydraulic cylinder, and an on-off valve disposed between the hydraulic accumulator and the control device. In order to provide a suspension function for the hydraulic cylinder while simultaneously ensuring safeguarding of the hydraulic cylinder and of the hydraulic accumulator against a pressure drop in the case of a tube break, the present invention provides a system that controls the on-off valve and the load holding device synchronously through a control pressure device, such that when the suspension function is activated the load holding device is opened and the on-off valve is closed.

An improved hydraulic arrangement is provided for a spring support system. The arrangement comprises a hydraulic cylinder, a hydraulic reservoir, a hydraulic fluid feeder, a hydraulic accumulator, a first control valve between the hydraulic cylinder and the accumulator, a second control valve between the hydraulic cylinder and the hydraulic reservoir as well as an automatic shut-off valve and a controller with a lifting position, a lowering position and a neutral position for the hydraulic cylinder. In order to prevent different pressure loads between the accumulator and the hydraulic cylinder, it is suggested to equalize the pressure between the accumulator and the hydraulic cylinder, without impairing the spring support system or the automatic shut-off valve. Accordingly, the accumulator is suitably connected to a non-return valve and to a flow restrictor or orifice.

A hydraulic arrangement for implementing a float position is provided. The arrangement includes: a hydraulic cylinder having a first chamber and a second chamber, a first supply pipe connected to the first chamber and a second supply pipe connected to the second chamber; a volumetric control valve assembly located within a hydraulic pipe and arranged between the first and second chamber; a hydraulic fluid feeder in fluid communication with a hydraulic reservoir; and a controller having a raise position, a lower position, a neutral position, and a float position to control the hydraulic cylinder. The second supply pipe is fluidly connected to the hydraulic reservoir and the first and second supply pipes are substantially prevented from being fluidly connected to the hydraulic fluid feeder when the controller is in the float position.

A hydraulic arrangement is provided for a tool locking device of a loader. The hydraulic arrangement comprises a hydraulic cylinder with first and second chambers, which cylinder has a first position for unlocking and a second position for locking, a first supply line hydraulically connected to the first chamber, a second supply line hydraulically connected to the second chamber and a control valve hydraulically connected to the first chamber. So as to prevent the faulty actuation of the hydraulic cylinder, it is proposed that the control valve has a first position and a second position, the control valve in the first position allowing hydraulic fluid to flow only in the direction of the first chamber and in the second position allowing hydraulic fluid to flow both to the first chamber and out of the first chamber and the control valve being controlled such that it assumes the first position when the hydraulic cylinder assumes its first position. In order to bring the hydraulic cylinder from the second position to the first position, the control valve always has to be moved to the second position first.

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Mannheim, Germany

Marcus Bitter