Deere + Company

Helmut Schaefer

Scott R Wiens

Christian Brueser

Guenter Rheinheimer

Harm-Hendrik Lange

Marcus Bitter

Steffen Frassek

A transmission control circuit for controlling a system pressure provided by a pressure pump in a transmission. The circuit includes a pressure control valve and an electronic control unit. Load states and operating states of the working machine can be detected by the control unit and transmission input torque limits associated with the load states and state values representing at least one first operating state and state values representing at least one second operating state are stored therein. The first operating state corresponds with the maximum system pressure and the second operating state corresponds with a reduced system pressure compared to the maximum system pressure. The circuit includes a pressure limiting valve activated by the control unit to overrule the pressure control valve in order to variably set the reduced system pressure.

Transmission control circuit

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

The invention concerns a system for supplying hydraulic fluid to a hydraulic system, with an operating reservoir that accepts the hydraulic fluid provided for the operation of the hydraulic system and an auxiliary reservoir connected to the operating reservoir over a hydraulic line for intermediate storage of hydraulic fluid withdrawn from the operating reservoir. According to the invention, an air pump is available that is connected on the one hand on its low pressure side to a suction line that ends in a fluid free area of the auxiliary reservoir, so that a negative pressure can be built up in the auxiliary reservoir as against the external atmospheric pressure, and that is connected, on the other hand, to a control line that is provided with a control opening that is covered by the hydraulic fluid in the operating reservoir at least before the air pump is put into operation.

System for supplying hydraulic fluid

A replaceable shift pad which can be mounted on the end of a shift fork comprises two plate-like side legs which are interconnected and parallel to each other. The inner sides of the side legs contact appropriate side surfaces of the shift fork. The outer sides of the side legs comprise sliding planes for sliding force transmission between the shift fork and a rotating shift sleeve. To provide a large supported area between the shift fork and the shift sleeve and to provide a shift pad which is resistant against vibratory stress it is suggested to connect the two side legs to each other by connecting means which are in line with the side legs, and which are tangentially orientated with regard to the shift sleeve rotation direction and extend beyond the end of the shift fork.

Plastic slider pad for gearbox shift fork

A valve for flow control with a flow recess and with a valve seat inside the flow recess is located beyond the axis of rotation of a rotating component and extends parallel to the axis of rotation. Inside the flow recess there is a movable valve body which interacts with the valve seat. A return spring takes effect on the valve body and the valve body is pressed in a closed position in the valve seat by the flow medium.

Flow control valve for rotating component

The cooling of a hydraulically-operated wet clutch with coolant is primarily required during the slippage phase when the linings are heated by the slip, that is, when the torque transmitted by the clutch is less than the torque delivered by the engine. A coolant flow control is provided in which a coolant control valve is controlled in such a way that it interrupts the coolant flow to the clutch during operation with clutch engaged or disengaged and opens the coolant flow to the clutch during the engagement process of the clutch and, if required, for a predetermined time interval following the engagement process. However, the coolant control valve only opens the coolant flow to the clutch during the disengagement process if the slippage phase during disengagement lasts longer than a predetermined second time interval.

Growing community of inventors

Ketsch, Germany

Helmut Schaefer