Abstract: Proposed is a system for operating and lubricating a clutch of a work vehicle. The system includes a forward-backward switching clutch portion connected to a first transmission hydraulic line, a main transmission clutch portion connected to the first transmission hydraulic line so as to be disposed in parallel with the forward-backward switching clutch portion, an auxiliary transmission clutch portion connected to a second transmission hydraulic line disposed in parallel with the first transmission hydraulic line, and a lubricating oil supply portion configured to supply oil as a lubricant to each clutch friction element. The lubricating oil supply portion includes a clutch lubrication valve unit, and is configured to always allow oil supply to the clutch friction elements of each of the main transmission clutch portion and the auxiliary transmission clutch portion, and is configured to intermittently allow oil supply to the clutch friction element of the forward-backward switching clutch portion.

Abstract: A harvester power takeoff (PTO) clutch system includes a detachable PTO extension module and transmission gearbox housing, which has a clutch compartment and a clutch service port through which the clutch compartment can be accessed. A PTO clutch is disposed in the clutch compartment, while a clutch shaft extends from the PTO clutch and projects from the clutch compartment through the clutch service port. The detachable PTO extension module includes, in turn: a PTO housing extension mounted to the transmission gearbox housing; a PTO shaft rotatably coupled to the PTO clutch and projecting from the PTO housing extension in a direction opposite the transmission gearbox housing; an inner extension bearing disposed in the PTO housing extension and rotatably supporting the clutch shaft; and an outer extension bearing further disposed in the PTO housing extension and rotatably supporting the PTO shaft.

Abstract: Presented are clutch-type engine disconnect devices, methods for making/using such disconnect devices, and motor vehicles equipped with such disconnect devices. An engine disconnect device includes a notch plate, which has multiple notches and attaches to a torque converter, and a pocket plate, which has multiple pockets and attaches to an engine's crankshaft. A pawl is movably mounted within each notch; these pawls selectively engage the notches with the pockets. A notch plate insert is nested within each notch, supporting thereon one of the pawls. A selector plate interposed between the pocket and notch plates moves from a first position, to shift the pawls out of engagement with the pockets, and a second position, to move the notch plate inserts within the notches and allow the pawls to engage the notches with the pockets to thereby lock the notch plate to the pocket plate to rotate in unison with each other.

Abstract: A method for controlling an electric oil pump (EOP) of a hybrid vehicle may include determining whether or not the hybrid vehicle is in a decelerating situation in an EV mode, driving the EOP at an RPM at a point L, corresponding to a minimum RPM of the EOP to form a target line pressure of a transmission, upon determining that the hybrid vehicle is decelerating in the EV mode, determining whether or not an RPM of a turbine is equal to or greater than a predetermined reference RPM, and driving the EOP at an RPM acquired by adding a predetermined additional RPM to secure an additional flow rate of automatic transmission fluid supplied to a balance chamber of an engine clutch to the RPM at the point L, upon determining that the RPM of the turbine is equal to or greater than the predetermined reference RPM.

Abstract: A drive module for a vehicle includes an input extending along an axis and configured to be driven by an engine. An electric motor has a rotor carrier hub configured to be rotated about the axis. The rotor carrier hub is non-rotatably connected to a torque converter cover and is selectively coupled to the input via a clutch. The rotor carrier hub has an inner surface defining an interior, an outer surface defining an exterior, and a plurality of holes extending through the rotor carrier hub from the inner surface to the outer surface to enable oil to transfer from the interior to the exterior. This provides a controlled and relative constant oil flow for cooling the drive module.

Abstract: A friction engagement element control system is provided, which includes a friction engagement element including friction plates, and an actuation system configured to engage an input-side friction plate with an output-side friction plate with a pushing force, the friction plates having a negative slope characteristic in which a friction coefficient thereof decreases as a rotational difference between the friction plates increases, a rotational difference sensor of the friction engagement element, a separator configured to divide a variation in the detected rotational difference into a high-frequency component that is a vibration component and other low-frequency components, and a controller configured to control a pushing force only for the vibration component of the rotational difference so that the negative slope characteristic becomes a positive slope characteristic in which a frictional force of the friction engagement element decreases as the rotational difference decreases, when engaging the friction e

Abstract: This clutch control device is provided with: a supply valve and a supply valve control unit, which control the supply of an operating fluid to a pressure chamber; a first discharge valve and a first discharge valve control unit, which control the discharge of the operating fluid in the pressure chamber; and a second discharge valve and a second discharge valve control unit, which control the discharge of the operating fluid in the pressure chamber. When it is determined that the engagement and disengagement switching of a clutch device 2, which is necessitated by the discharge of the operating fluid in the pressure chamber, is required, the first discharge valve is controlled to be opened and then the second discharge valve is controlled to be opened.

Abstract: A clutch control method for a vehicle may include determining, by a controller, whether a tip-in has occurred during an in-gear state of a transmission; increasing the clutch slip rapidly to a first target slip by the controller; feedback-controlling, by the controller, so that the clutch slip is reduced toward a second target slip during a predetermined first control time period after the increasing of the clutch slip; controlling, by the controller, a clutch of the transmission with a first target slip angular acceleration after the predetermined first control time period has elapsed; feedback-controlling by the controller so that target slip angular acceleration of the clutch gradually becomes zero during a predetermined second control time period; and feedback-controlling by the controller so that the clutch slip becomes a third target slip after the predetermined second control time period has elapsed.

Abstract: The clutch control device comprises: a pump that feeds oil to a hydraulic clutch; a control part that controls the pump; an input-side oil channel through which oil suctioned into the pump from an oil tank passes; an output-side oil channel connecting the pump and the hydraulic clutch; a pressure sensor; a connecting oil channel connected to the input-side oil channel and the output-side oil channel; and a solenoid valve that interrupts or allows the flow of oil in the connecting oil channel. The opening degree of the valve can be adjusted. When a drive shaft and a driven shaft are connected by the hydraulic clutch, the control part adjusts the opening degree of the valve on the basis of the pressure of oil in the output-side oil channel and the number of rotations made by the driven shaft while monotonically increasing the number of rotations of the drive part.

Abstract: A lubrication system for a power transmission unit that supplies oil to a starting clutch in an appropriate amount irrespective of an engagement state of the starting clutch. When the friction clutch is completely engaged or disengaged, a first control valve is brought into a low inflow rate mode, and the second control valve is brought into a low outflow rate mode. When the friction clutch is engaged while causing a slip the first control valve is brought into a high inflow rate mode, and the second control valve is brought a high outflow rate mode.

Abstract: The invention relates to a method for controlling the oil level (h3) in a differential gearbox for a vehicle having an oil sump (3) and an oil reservoir (4) that is pneumatically separated from the oil sump (3). The oil reservoir (4) is connected to the oil sump (3) by way of at least one oil channel (34), and the oil sump (3) is connected to a pneumatic pressure source (8) by way of at least one control valve (7) and an air line (5), wherein in at least one position (B) of the of a the control valve (7), the pressure source (8) is pneumatically connected to the oil sump (3). In order to improve the efficiency, at least one first characteristic operating parameter of the vehicle, according to the invention, is detected, and the control valve (7) is operated in dependence of at least said first characteristic operating parameter, wherein the vehicle speed (v) is selected as first characteristic operating parameter.

Abstract: A clutch control device includes a pump to feed oil to a hydraulic clutch, an input side oil passage connecting an oil tank and the pump and through which oil sucked from the oil tank to the pump passes, and an output side oil passage connecting the pump and the hydraulic clutch and through which oil that is pressurized by the pump and is fed from the pump to the hydraulic clutch passes. A damper connected to the input side oil passage and the output side oil passage includes an oil container containing oil, a partition that partitions the oil container into first and second spaces along a predetermined direction and at least a portion of which is movable in the predetermined direction, a first connection oil passage connecting the first space and the input side oil passage, a second connection oil passage connecting the second space and the output side oil passage, and an elastic portion that applies a force to the partition to move the partition toward the second space in the predetermined direction.

Abstract: A clutch hydraulic control method and the double clutch transmission system may include performing a clutch pack flow rate control, which pre-fills a flow rate for clutch engage in a clutch pack of a clutch before shifting, when a shifting attempt is detected in a clutch controller.

Abstract: An arrangement for a multi-clutch assembly including a popoff valve is disclosed. The arrangement also includes a first clutch, a second clutch, and a spool valve assembly. Depending on the mode, the popoff valve either provides a flowpath for residual hydraulic fluid from a latching chamber of the spool valve assembly to a vent of the popoff valve, or provides a flowpath for supplying hydraulic fluid to the latching chamber of the spool valve assembly via a fluid connection from a supply inlet to a latch port of the popoff valve.

Abstract: A shift control device includes: a hydraulic circuit, an actuation valve, a control unit, and a pressure holding valve. The hydraulic circuit is provided with a supply oil passage coupled to a hydraulic oil supply source, a drain oil passage coupled to a tank, and an actuator oil passage coupled to a travel actuator. The actuation valve is provided in the hydraulic circuit and couples the actuator oil passage to the supply oil passage or the drain oil passage. The control unit switches the actuation valve in accordance with a shift position command of a shift operation device. The pressure holding valve is provided in the drain oil passage and holds a pressure of the drain oil passage at a predetermined pressure.

Abstract: A method for controlling a pneumatic actuator (1) of a transmission having at least one sealing element (6, 7), arranged between two elements (2, 3) of the clutch actuator (1) that move relative to one another, and within a specifiable operating temperature range in which leakproofness of the clutch actuator (1) is ensured. The clutch actuator (1) is acted upon with compressed air from an air supply system for actuating a shifting and/or starting clutch arranged between a drive aggregate and a transmission. In order to warm up the clutch actuator (1), if a temperature of the clutch actuator (1) is lower then a glass transition temperature of the at least one sealing element (6, 7), the drive aggregate is operated at a higher rotational speed compared to the idling speed of the drive aggregate.

Abstract: A system for controlling fluid pressure to a transmission system through a MEMS microvalve includes a transmission controller configured to receive a target command pressure, a current system command pressure input signal, and a transmission system operating temperature. A power determination module determines a temperature-related power factor from the target command pressure, the current system command pressure input signal, the transmission system operating temperature received in the controller, and a look-up table within the controller. A power signal module adjusts the current system command pressure input signal by the temperature-related power factor and applies the adjusted current system command pressure input signal to the MEMS microvalve via the controller.

Abstract: Provided is a work-machine erroneous forward/backward travelling operation notifying device capable of improving safety by notifying, when a travel direction inputted to an operation input unit does not conform to the condition of a transmission clutch, an operator of the non-conformance. Whether the conditions of clutches 121 to 124 conform to a travel direction inputted to a selection lever 141 is determined on the basis of a pressure Pf sensed by a first pressure sensor 133a or a pressure Pr sensed by a second pressure sensor 134a and the travelling direction inputted to the selection lever 141. When it is determined that the conditions of the clutches 121 to 124 do not conform to the travel direction inputted to the selection lever 141, a vehicle 10 is notified that an erroneous operation will occur.

Abstract: A method for stopping of a motor vehicle including providing a creep torque via a drive train of the motor vehicle and then increasing, independently of the driver, engine speed of a drive engine of the drive train to increase a drive torque of the drive engine and simultaneously increasing, independently of the driver, a braking torque of a brake system of the motor vehicle to balance the drive torque and the braking torque of the motor wherein the maximum braking torque is as great as the creep torque during a standstill of the motor vehicle. The method then maintains the braking torque and simultaneously reduces the engine speed of the drive engine to point at which the motor vehicle comes to a standstill.

Abstract: A hydraulic control system of an automatic transmission for a vehicle provided with an idle stop and go (ISG) system includes a mechanical hydraulic pump driven by a torque of an engine, the mechanical hydraulic pump pumping a fluid stored in an oil pan, a regulator valve, a manual valve, a linear solenoid valve for controlling the hydraulic pressure supplied from the manual valve through the second hydraulic line and for supplying the controlled hydraulic pressure to a third hydraulic line, a switch valve, and an electric hydraulic pump driven by electric energy for pumping the fluid stored in the oil pan through a fifth hydraulic line and for feeding the pumped fluid to a sixth hydraulic line connected to the fourth hydraulic line.

Abstract: A piston-cylinder unit (40) for hydraulic actuation of a clutch in a vehicle, including a piston (42), a cylinder (41) and a sealing element (43). The piston cylinder unit is fluidically linked to a fluid circuit (44), the piston (42) is axially displaceable in the cylinder, and the sealing element is arranged sealingly between the piston and the cylinder, characterized in that a sensor is arranged in or on the piston-cylinder unit, by which sensor a pressure can be measured in the interior of the piston-cylinder unit and/or in the fluidically linked fluid circuit. A method for operating the piston-cylinder unit is also provided.

Abstract: A hydraulic control device including: a throttle valve; a pressure regulating valve; an on/off solenoid valve of a normally open type that allows communication therethrough when not energized; and a failure circuit that, when power supply to the linear solenoid valve and the on/off solenoid valve is cut off, supplies a certain hydraulic pressure based on switching off of the on/off solenoid valve to the control oil chamber of the pressure regulating valve.

Abstract: A method for characterizing a fluid control solenoid with current compensation is described. A current command is sent to the fluid control solenoid. The current command indicates a desired current value related to a desired fluid output pressure to be applied to the solenoid. An actual fluid output pressure is measured at a valve associated with the fluid control solenoid for the desired current value applied to the solenoid. An actual current received value at the fluid control solenoid is also measured. Post processing is then applied. A compensated current value related to the actual fluid output pressure is determined based on a difference between the current command and the actual current received value. Methods for dynamic current compensation are also described.

Abstract: An example robot includes movable members, a hydraulic system including at least (i) hydraulic actuators configured to operate the movable members, and (ii) a source of hydraulic fluid, and a controller. The controller may be configured to: determine a task to be performed by the robot, where the task includes a plurality of phases; cause hydraulic fluid having a first pressure level to flow from the source to the hydraulic actuators for the robot to perform a first phase of the plurality of phases of the task; based on a second phase of the task, determine a second pressure level for the hydraulic fluid; and adjust, based on the second pressure level, operation of the hydraulic system before the robot begins the second phase of the task.

Abstract: A vehicle includes a motive power source, a transmission, and a clutch system. The vehicle further includes a controller that causes the clutch system to generate a generally constant clutch pressure to mechanically couple the motive power source and transmission as a line pressure associated with the transmission varies.

Abstract: A hydraulic control system for a clutch of a transmission having a plurality of torque transmitting mechanisms and includes a source of pressurized hydraulic fluid, a clutch pressure regulating valve, a clutch pump valve, a first and a second fluid flow check valve, a pressure valve, a first torque transmitting mechanism actuation device, and a pressure control solenoid.

Abstract: A powertrain system in a hybrid vehicle includes a hydraulic device, a pilot valve, and a regulator valve. The pilot valve is operably connected to the hydraulic device and configured to actuate. The pilot valve includes at least one micro-electro-mechanical systems (MEMS) based device. The regulator valve is operably connected to the pilot valve and the hydraulic device. The regulator valve is configured to direct fluid to the hydraulic device based on the actuation of the pilot valve.

Abstract: A clutch assembly includes a fluid-actuated piston that allows clutch usage in both high pressure and low pressure applications. The configuration of the clutch assembly allows the piston to be used with different seal arrangements. These different seal configurations create differently sized piston surface areas against which the inlet pressure will act to drive the piston. The ability to change the size of the affected piston surface areas allows for the piston to receive essentially the same driving force under both high pressure and low pressure applications. Thus, the clutch assembly enables use of high hydraulic pressure (e.g., 320 psi) in combination with a seal arrangement that creates a small piston-driving surface area, and also use of low pneumatic pressure (e.g., 120 psi) with a seal arrangement that creates a large piston-driving surface area.

Abstract: A front module disposed between an engine and a torque converter, and a method for coupling or decoupling the front module to the torque converter is provided. The front module has a housing that defines a cavity and has at least one access window, but preferably two access windows. The access windows may each include a notch. Disposed in the housing of the front module is a motor/generator and an engine disconnect clutch. A flexplate connects an output of the front module to the torque converter. The flexplate has a plurality of notches located on a periphery of the flexplate, and the flexplate is connected to the torque converter by a plurality of fasteners. Both the notches on the periphery of the flexplate and the plurality of fasteners are accessible through the access windows.

Abstract: A pump apparatus with a switching valve includes an actuator that is rotationally driven, a pump, a switching valve and a driving power interrupting device. The pump discharges a fluid sucked by rotational driving of the actuator. The switching valve is changed in phase by the rotational driving of the actuator so as to be switchable among a plurality of destinations of the fluid discharged from a pump chamber of the pump. The driving power interrupting device for a valve is switchable between a state where rotational driving power of the actuator is transmitted to the switching valve and a state where the rotational driving power of the actuator is interrupted.

Abstract: The present disclosure relates to a limited-slip driveline apparatus including a first driveline component that is rotatable relative to a second driveline component. The driveline apparatus also includes a clutch configured to resist relative rotation between the first driveline component and the second driveline component at least when the clutch is actuated. The driveline apparatus further includes an actuation arrangement for actuating the clutch. The actuation arrangement includes a hydraulic pump that pumps hydraulic fluid through a hydraulic circuit when relative rotation exists between the first and second driveline components. The hydraulic pressure generated by the hydraulic pump within the hydraulic circuit is used to actuate the clutch. The actuation arrangement also includes a flow regulating valve for regulating a hydraulic fluid flow rate through the hydraulic circuit.

Abstract: An actuator system for hydraulic actuation of a clutch comprises a master cylinder with a master piston, a readjustment container for containing hydraulic fluid, a connection opening between the readjustment container and the master cylinder, where a degree of openness of the connection opening is dependent on the position of the master piston, and a hydraulic actuator to control a position of the master piston. In an actuator system, a control device for controlling the hydrostatic actuator is also provided, such that a speed of motion of the master piston is high while the connection opening is wide open, and low while the connection opening is open a little. In a method according to the disclosure, a position of the master piston is detected, and the actuator is controlled at different speeds depending on the position or the degree of openness.

Abstract: A hydraulic control system of an automatic transmission includes a clutch compensator feed circuit that is in communication with clutch apply circuit exhaust fluid. The clutch compensator feed circuit receives exhaust fluid from one or more apply clutches, or other torque transmitting device(s), and feeds the exhaust fluid to the balance side of the clutch or other torque transmitting device. The clutch compensator feed circuit may be open to atmospheric pressure, such that the clutch compensator feed circuit is not pressurized with respect to atmospheric pressure.

Abstract: A latch valve includes a first port containing line pressure, a second port containing control pressure, a third port located between the first and second ports, alternately connecting the first and second ports to a transmission control element, and a fourth port containing control pressure that tends to close the second port and open the first port in opposition to a spring force.

Abstract: A vehicle includes an engine, a transmission, and a controller which executes a method. The transmission includes a clutch having an actuator which applies the clutch using position-based control logic. The transmission also includes a fluid pump and a variable-force or other solenoid valve positioned downstream of the pump and upstream of the clutch. The valve outputs a flow rate (Q) for a corresponding solenoid control current (I). The controller adapts a calibrated Q vs. I characteristic table of the valve for different transmission temperatures by applying closed-loop position control signals to the actuator at the different transmission temperatures and recording a null point(s) describing the corresponding solenoid control current (I) at a zero flow rate condition. The controller calculates an offset value for solenoid control current (I) using the recorded null point(s), applies the offset value to the characteristic table, and controls the clutch using the adapted characteristic table.

Abstract: A hydraulic control system for a clutch of a transmission includes a source of pressurized hydraulic fluid, a line pressure regulator valve, a clutch control valve, a control valve bore, and a bypass sleeve. The bypass sleeve is installed in the control valve bore and includes an axial bore, and a first and a second port. The first port is in communication with the axial bore and the first of the plurality of ports of the control valve bore, the second port is in communication with the axial bore and the second of the plurality of ports of the control valve bore, and the axial bore is not in communication with the remainder of the plurality of ports of the control valve bore.

Abstract: An internal combustion engine is provided with a plurality of hydraulic clutches, a plurality of hydraulic controlling valves for individually controlling the oil pressure for the hydraulic clutches, and a plurality of clutch oil pressure sensors for individually detecting the controlling oil pressure of controlling oil supplying paths interconnecting the hydraulic controlling valves and the hydraulic clutches. The oil pressure sensors individually correspond to the hydraulic clutches compactly, thereby to preventing an increase in size. The clutch oil pressure sensors are provided on an engine main body so as to be disposed in the proximity of and in parallel to each other while axial directions thereof are directed in a forward and backward direction of a saddle type vehicle in a state in which the engine main body is mounted on the saddle type vehicle.

Abstract: A valve body assembly for a hybrid drive unit includes a pressure regulator valve, a first on/off shift valve for controlling a stationary clutch, a second on/off shift valve for controlling a rotating clutch, and a third on/off shift valve for controlling a damper bypass clutch. The control system controls the stationary clutch and the rotating clutch to operate the hybrid drive unit in four different modes. The first shift valve, the second shift valve and the third shift valve do not include a regulated pressure feedback port, nor a pressure switch for indicating a clutch fill level.

Abstract: A pneumatic decoupling device for an electromechanical actuator, in particular, for flight applications includes a pressure accumulator housing for storing a compressed gas, which can be released to a decoupling mechanism of an electromechanical actuator for separating the drive components, so that in the event of a decoupling the electromechanical actuator runs totally freely.

Abstract: Disclosed is an electrically controlled silicon oil fan clutch rotary valve device. The valve device is based on a magnetic mandrel, including a triangle, a driven disc, a driving disc, and a guide disc intercombined, which achieves control over flow of silicon oil by controlling rotation of a valve, and achieves precise control over positions by resetting through a reset torsion spring and using outer teeth and inner teeth of the driving disc and the driven disc as well as a stop device. In the present invention, the valve may be controlled to be stable at an appropriate position through the size of the current of the coil, so as to achieve a stepless speed and achieve a purpose of precisely controlling the clutch.

Abstract: A hydraulic clutch control device of a vehicle power unit in which the oil pressure control valve is prevented from being exposed above the oil level even when a vehicle body inclines frontward or rearward. A housing chamber housing an actuator is formed in a housing chamber forming body attached to an engine main body and an oil pressure control valve partially facing the housing chamber is supported by the housing chamber forming body. An oil return hole used to return excess hydraulic oil from the housing chamber into the engine main body is provided in the housing chamber forming body to communicate with an upper portion of the housing chamber at an end portion of the housing chamber on a side close to the oil pressure control valve.

Abstract: A hydraulic arrangement for the activation of two actuators, with a hydraulic pressure supply unit which is assigned jointly to the two actuators. The pressure supply unit is designed to be reversible in its direction of action, so that, depending on the direction of action, in each case only one of the actuators is driven.

Abstract: An automatic transmission for a vehicle includes a hydraulically-controlled component and a pilot valve. The pilot valve includes at least one micro-electrical-mechanical systems (MEMS) based device. The pilot valve is operably connected to and is configured for actuating the hydraulically-controlled component. The pilot valve additionally includes a regulating valve operably connected to the pilot valve and to the hydraulically-controlled component. The regulating valve is configured to direct fluid to the hydraulically-controlled component when actuated by the pilot valve.

Abstract: A continuously variable transmission (CVT) for a vehicle includes a hydraulically-controlled component and a pilot valve. The pilot valve includes at least one micro-electrical-mechanical-systems (MEMS) based device. The pilot valve is operably connected to and is configured for actuating the hydraulically-controlled component. The pilot valve additionally includes a regulating valve operably connected to the pilot valve and to the hydraulically-controlled component. The regulating valve is configured to direct fluid to the hydraulically-controlled component when actuated by the pilot valve.

Abstract: A pressure and flow control system includes a hydraulically-controlled component, a pilot valve, and a regulating valve. The pilot valve is configured to produce a pilot signal and includes a first valve, which is a MEMS microvalve. The regulating valve is in fluid communication with the pilot valve, and is configured to receive the pilot signal. The regulating valve is further configured to output a control signal, which controls the hydraulically-controlled component.

Abstract: According to an embodiment, a valve assembly is provided for use with a fluid system for controlling flow rate to a fluid circuit for cooling and/or lubricating a clutch assembly in a transmission. The spool valve has a first outlet and a second outlet in fluid communication with the fluid circuit. The spool valve has a first configuration with zero flow to the fluid circuit, a second configuration providing a first flow to the fluid circuit through the first outlet, and a third configuration providing a second flow to the fluid circuit through the first and second outlets. The first outlet has a metering orifice. The flow across the valve is a function of the stroke distance of the spool.

Abstract: In a linear solenoid 107n, an electromagnetic coil 71n, a pressure sensor 72n, and label resistors 73n and 74n for correcting an inherent variation in a pressure detection characteristic are integrated; the standard characteristic of the pressure sensor 72n is stored in a control module 120M; when driving is started, the resistance values of the label resistors 73n and 74n are read, the pressure detection characteristic of the utilized pressure sensor 72n is corrected, and an excitation current for the electromagnetic coil 71n is controlled in such a way that a target adjusted hydraulic pressure is obtained. Even when due to a change in the oil temperature, the valve opening characteristic of the linear solenoid 107n changes, the adjusted hydraulic pressure is controlled to be constant.

Abstract: Taught herein is a clutch control apparatus that suppresses oil leakage from a seal member of a hydraulic cylinder even when vibration occurs, without enhancing sealability of the seal member per se. The clutch control apparatus includes normally-closed first clutch, a hydraulic cylinder, a piston, a lip seal and a pressure holding control section. The first clutch is disposed between an engine and driving wheels and is held in engagement by an elastic force applied to the first clutch CL1 by a diaphragm spring. The lip seal is disposed on the piston and enhances sealability between the piston and a housing slide surface in accordance with an increase in hydraulic pressure in the piston chamber. When the first clutch is engaged, the pressure holding control section applies a hydraulic pressure to retain the sealability of the lip seal to the piston chamber while maintaining engagement of the first clutch.

Abstract: Providing a hydraulic control apparatus for a vehicular automatic transmission, which makes it possible to design an oil pump with a reduced delivery capacity, thereby permitting an improvement of fuel economy of a vehicle. The hydraulic control apparatus includes a supply passage connecting/disconnecting valve 114A which is operated, in synchronization with a switching operation of a lock-up relay valve 114, to apply a modulator pressure PM via an orifice 118 to a lock-up clutch 18, for placing the lock-up clutch 18 in the lock-up on state, and to inhibit the application of the modulator pressure PM to the lock-up clutch 18, for placing the lock-up clutch 18 in its lock-up off state.

Abstract: The invention relates to a fluid friction clutch (1) having a housing (2, 3), having a clutch disk (4) which is rotatable relative to the housing (2, 3), and which is rotatably arranged on an end (5) of a shaft (6) which is mounted centrally within the housing (2, 3); having a working chamber (9) between the housing (2, 3) and the clutch disk (4); having a storage chamber (10) for clutch fluid; having a supply duct (11) which leads from the storage chamber (10) to the working chamber (9); having a stationary clutch part (13) relative to which the housing (2, 3) is rotatable; and having a pump element (14), wherein the pump element (14) defines a shear gap (12) with an annular wall (19) arranged in the storage chamber (10), wherein an active element (7) is fastened to the housing (2, 3), and wherein the shear rate in the shear gap (12) can be regulated by means of an electric motor (20) which is mounted on the shaft (6).