Abstract: A solenoid valve for controlling a hydraulic system having a coil which is composed of an electrical conductor, an armature which is situated at least partially inside the coil and is connected to a valve element for opening and closing a flow opening of the solenoid valve, and a hydraulic fluid-filled valve chamber that accommodates the armature and communicates fluidically with the hydraulic system. The armature is supported in movable fashion in the hydraulic fluid of the hydraulic system. In order to reduce the viscosity of the hydraulic fluid, the coil is situated so that a heating of the coil produced by a current flow produces a heating of the hydraulic fluid in the valve chamber.

Abstract: A drive system for a motor vehicle with a continuously driven primary axle and a selectably driven secondary axle has a differential that acts between the wheels of the secondary axle, and has a torque transmission device for transmitting a drive torque to the differential. The torque transmission device has a clutch and a pump, wherein the pump produces a hydraulic pressure in a first pressure chamber of the clutch when a speed difference occurs between the primary axle and the secondary axle. The first pressure chamber is connected via a connecting line to a second pressure chamber, which is associated with an actuating member of the differential, so that the pressure produced by the pump also permits an at least partial locking of the differential. The first pressure chamber is connected to a low-pressure chamber through a first discharge line, in which is arranged a first control valve.

Abstract: A clutch arrangement having an input element and an output element that are rotatable relevant to one another, a friction clutch and a pump. The friction clutch couples the input element with the output element in dependence on a hydraulic pressure in a pressure space of the clutch arrangement. The pump has a first pump part that is rotationally fixedly connected to the input element and a second pump part that is rotationally fixedly connected to the output element. The pump may be driven by a rotary movement of the input element and the output element relative to one another, with a pressure side of the pump being connected to the pressure space. An orifice having a substantially temperature independent leakage characteristic is arranged in a leakage line that leads from the pressure space to a low pressure space and which extends parallel to the pump.

Abstract: A drive system for a motor vehicle with a continuously driven primary axle and a selectably driven secondary axle has a differential that acts between the wheels of the secondary axle, and has a torque transmission device for transmitting a drive torque to the differential. The torque transmission device has a clutch and a pump, wherein the pump produces a hydraulic pressure in a first pressure chamber of the clutch when a speed difference occurs between the primary axle and the secondary axle. The first pressure chamber is connected via a connecting line to a second pressure chamber, which is associated with an actuating member of the differential, so that the pressure produced by the pump also permits an at least partial locking of the differential. The first pressure chamber is connected to a low-pressure chamber through a first discharge line, in which is arranged a first control valve.

Abstract: A method controlling a clutch arrangement that serves, in a powertrain of a motor vehicle, for the transmission of a torque from an input element to an output element. Starting from an activated state of the clutch arrangement, a respective estimated torque value is calculated in repeating calculation cycles. A torque build-up value is calculated in dependence on at least one speed difference value. A torque reduction value is calculated in dependence on at least the last calculated estimated torque value. The estimated torque value is re-calculated on the basis of the last calculated estimated torque value by up integration of the calculated torque build-up value and down integration of the calculated torque reduction value. The recalculated estimated torque value is compared with a torque threshold value. The clutch arrangement is deactivated when the recalculated estimated torque value is below the torque threshold value.

Abstract: A multi-disk clutch having a plurality of interengaging disks movable along a longitudinal clutch axis and a resetting device for the mutual release of adjacent disks along a release distance, with the release distance being bounded by an abutment device. The abutment device includes at least one contact section of a clutch part movable along the longitudinal clutch axis and at least one contact section of an axially fixed clutch part, with the moving clutch part and the axially fixed clutch part having different thermal coefficients of expansion and with the contact sections at both sides cooperating such that the bounding of the release distance varies in dependence on the temperature, with at least one of the contact sections having a sloping surface.

Abstract: The invention relates to a solenoid valve for controlling a hydraulic system, having a coil, which is composed of an electrical conductor, having an armature, which is situated at least partially inside the coil and is connected to a valve element for opening and closing a flow opening of the solenoid valve, and having a hydraulic fluid-filled valve chamber that accommodates the armature and communicates fluidically with the hydraulic system. The armature is supported in movable fashion in the hydraulic fluid of the hydraulic system; in order to reduce the viscosity of the hydraulic fluid, the coil is situated so that a heating of the coil produced by a current flow produces a heating of the hydraulic fluid in the valve chamber.

Abstract: A method controlling a clutch arrangement that serves, in a powertrain of a motor vehicle, for the transmission of a torque from an input element to an output element. Starting from an activated state of the clutch arrangement, a respective estimated torque value is calculated in repeating calculation cycles. A torque build-up value is calculated in dependence on at least one speed difference value. A torque reduction value is calculated in dependence on at least the last calculated estimated torque value. The estimated torque value is re-calculated on the basis of the last calculated estimated torque value by up integration of the calculated torque build-up value and down integration of the calculated torque reduction value. The recalculated estimated torque value is compared with a torque threshold value. The clutch arrangement is deactivated when the recalculated estimated torque value is below the torque threshold value.

Abstract: A clutch arrangement responsive to a speed difference including an input element and an output element that are rotatable relevant to one another, a friction clutch, and a pump. The friction clutch couples the input element with the output element in dependence on a hydraulic pressure prevails in a pressure space of the clutch arrangement. The pump has a first pump part that is rotationally fixedly connected to the input element and a second pump part that is rotationally fixedly connected to the output element. The pump may be driven by a rotary movement of the input element and the output element relative to one another, with a pressure side of the pump being connected to the pressure space. An orifice having a substantially temperature independent leakage characteristic is arranged at a leakage line that leads from the pressure space to a low pressure space and extends parallel to the pump.

Abstract: A multi-disk clutch having a plurality of interengaging disks movable along a longitudinal clutch axis and a resetting device for the mutual release of adjacent disks along a release distance, with the release distance being bounded by an abutment device. The abutment device includes at least one contact section of a clutch part movable along the longitudinal clutch axis and at least one contact section of an axially fixed clutch part, with the moving clutch part and the axially fixed clutch part having different thermal coefficients of expansion and with the contact sections at both sides cooperating such that the bounding of the release distance varies in dependence on the temperature, with at least one of the contact sections having a sloping surface.