Abstract: A coupling device with two parts which are coaxially rotatable relative to one another, comprising a friction coupling whose friction plates are alternately connected to each of the rotatable parts. Further the coupling device comprises an actuating device for the friction coupling, which comprises an annular chamber formed in one of the rotatable parts and containing a highly viscous fluid. A rotational member is arranged in the annular chamber and is drivingly connected to the other one of the rotatable parts. The actuating device, when the rotatable parts rotate relative to one another, causes an increase in pressure of the highly viscous fluid for the purpose of loading the friction coupling. When the relative rotation between the rotatable parts exceeds a given value, the increase in pressure is checked to limit the torque transferred through the friction coupling.

Abstract: Line pressure is adjusted by one valve for supplying the pressure to control the engagement of a clutch in normal and abnormal operating conditions. In the normal operating condition, the valve control pressure which is controlled by a starting clutch control valve 41 is used for the control of a clutch pressure control valve 42, so the line pressure from a line 61b is adjusted to control the engagement of the starting clutch 5. If there is a breakdown, two electrically controlled valves 41 and 45 are turned off, and the line pressure is applied through another line 64. As a result, the spool of a shift restriction valve 43 is shifted to the left, so the hydraulic oil is supplied to a pitot flange 51. In this condition, the pressure (correspondent pressure) which corresponds to the rotational speed of the engine is supplied as a signal pressure from a pitot pipe 53 through lines 66 and 67 to the shift restriction valve 43.

Abstract: The control method comprises the stages of: generating a reference torque signal, the instantaneous value of which indicates the desired value of the torque transmitted through the clutch; generating a reaction signal correlated to the position of an actuating member of the clutch, the position of the actuating member being comprised between a first end-of-travel position in which the clutch is completely open and a second end-of-travel position in which the clutch is completely closed; generating an estimated torque signal, the instantaneous value of which indicates the estimated value of the torque transmitted through the clutch, on the basis of the reaction signal and a transmissibility function of the clutch; and generating a control signal for adjusting the position of the clutch as a function of the reference torque signal and the estimated torque signal.

Abstract: A hydraulic coupling including a multi-plate clutch assembly operably connecting two relatively rotatable members and an actuator assembly for actuating the clutch assembly in response to speed differentiation between the two rotary members. The actuator assembly includes a hydraulic pump, a piston disposed in a piston chamber, and a fluid distribution system including a first flow path for supplying hydraulic fluid from a sump to the hydraulic pump and a second flow path for supplying hydraulic fluid from the hydraulic pump to the piston chamber. Hydraulic pressure in the piston chamber controls the magnitude of the clutch engagement force exerted by the piston on the clutch assembly. The fluid distribution system further includes a third flow path between the piston chamber and a clutch chamber.

Abstract: A coupling device for transmitting torque between a first part and a second part which are rotatable relative to one another is disclosed. The coupling device comprises a multi-plate coupling unit with axially alternating arranged first plates and second plates. The first plates are each connected in a rotationally fixed manner to one of the first part or the second part and the second plates are each connected in a rotationally fixed manner to the other of the first part or the second part. The coupling device further comprises an actuating assembly for axially loading the multi-plate coupling unit by means of a setting piston. The multi-plate coupling unit also comprises a first annular chamber filled with a highly viscous fluid and delimited by the setting piston, and a rotational member arranged in the annular chamber. The first annular chamber is formed in one of the first or second parts with the rotational member being connected in a rotationally fixed manner to the other of the first or second part.

Abstract: A hydraulic coupling for use in motor vehicle driveline applications to limit speed differentiation and transfer drive torque between two rotary members. The hydraulic coupling includes a multi-plate clutch assembly operably connecting the two relatively rotatable members, and a sealed actuator assembly for actuating the clutch assembly in response to the magnitude of speed differentiation between the two rotary members. The actuator assembly includes a hydraulic pump and a piston which are sealed relative to the clutch assembly. The sealed actuator assembly includes an internal recirculation path for supplying hydraulic fluid retained therein between a low pressure supply chamber at the inlet side of the hydraulic pump and a high pressure piston chamber provided at the discharge side of the hydraulic pump. Hydraulic pressure in the piston chamber controls the magnitude of the clutch engagement force exerted by the piston on the clutch assembly.

Abstract: A coupling device with two parts which are coaxially rotatable relative to one another, comprising a friction coupling whose friction plates are alternately connected to each of the rotatable parts. Further the coupling device comprises an actuating device for the friction coupling, which comprises an annular chamber formed in one of the rotatable parts and containing a highly viscous fluid. A rotational chamber is arranged in the annular chamber and is drivingly connected to the other one of the rotatable parts. The actuating device, when the rotatable parts rotate relative to one another, causes an increase in pressure for the purpose of loading the friction coupling.

Abstract: The hydraulic power transformer has a controllable, non-slip jumpering of the hydrodynamic system with insertion of a torsional vibration damper. The torsional vibration damper exhibits a device that varies the damping based on a liquid pressure acting in the vicinity of the device. This device preferably has a piston, which can be moved by the liquid pressure against a surface, and hence generates a damping.

Abstract: A hydraulic coupling includes a clutch assembly operatively connecting two rotary members and an actuator assembly for actuating the clutch assembly in response to speed differentiation between the two rotary members. The clutch assembly includes a multi-plate clutch pack alternately connected between the two rotary members within a clutch chamber. The actuator assembly includes a hydraulic pump, a piston disposed in a piston chamber, and a fluid distribution system having a first flow path between a supply chamber and the hydraulic pump, a second flow path between the hydraulic pump and the piston chamber, and a third flow path between the hydraulic pump and the clutch chamber. The fluid delivered to the piston chamber controls engagement of the piston with the clutch pack for controlling actuation of the clutch assembly. Additionally, the fluid delivered to the clutch chamber is used to cool and lubricate the clutch pack.

Abstract: A device for transmitting torque between two parts rotatably mounted relative to one another. The device comprises a friction coupling 12 having friction elements rotationally fixed to each of the parts. The friction elements are rotatably relative to one another. The friction coupling 12 is loadable by at least two movable pistons 19.sub.1, 19.sub.2, which delimit a pressure chamber 21 on one side. The pressure chamber 21 is filled with a viscous fluid, and is connected to a reservoir 26. The pressure chamber 21 is formed by a rotational housing 20 and the pistons 19.sub.1, 19.sub.2. The rotational housing 20 is connected with one of the rotatable parts. A rotational member 22 rotates inside the chamber 21 and is connected to the other rotatable part. A control member 23 is positioned in a pressure chamber 21 and faces of the rotational member and counter faces of the control member and constitute at least one shear channel 38 which communicates with the reservoir 26 and the pressure chamber 21.

Abstract: An actuating drive for actuating a friction clutch and an automated shift transmission, having valve units which enable a switching operation, on the one hand, of the friction clutch, and on the other hand, of the shift transmission. It is possible for a change to the switching state at the friction clutch to be triggered by a gear selection device. The valve unit that is assigned to the friction clutch is assigned a switching device which has a link between the actuating cylinder for the slot selection and the hydraulic circuit that is connected to the actuating cylinder for actuating the friction clutch and enables the driving, as required, of one or the other actuating cylinder.

Abstract: An hydraulic valve has two outlets and is switchable so that fluid can only be supplied to one outlet at a time. A spool with two seals is slidable in a housing under the action of two proportional solenoids and is urged to a central position by two springs where the seals block passage to both outlets. When the spool is moved in one direction it allows flow to one outlet and also allows flow via a bypass channel to an opposite side of the spool counteracting the force applied by the solenoid so that the force applied to an outlet can be controlled gradually.

Abstract: A coupling assembly has at least one friction coupling unit which comprises a driveable housing and a hub to be driven, and having differential-speed-dependent actuating means operating by a pressure agent and comprising a pump unit. The pump unit comprises housing parts and hub parts, which housing parts are rotatable relative to said hub parts with the one part of the pump unit being connected in a rotationally fixed way to the housing of the friction coupling unit and the other parts of the pump unit being connected in a rotationally fixed way to the hub of the friction coupling unit. The hub of the at least one friction coupling unit is receiving an outer joint part of a constant velocity universal joint.

Abstract: Torque is transmitted between two rotatable, coaxial shaft members in a stationary housing which includes a number of alternate clutch discs connected to the shaft members and engageable to counteract differential rotational speed therebetween, and a hydraulic arrangement driven by the speed differential. The arrangement includes a number of pistons which are axially movable in the housing and are intended to create a hydraulic pressure in the arrangement and thereby to engage the clutch discs, piston actuating devices engaging a shaft member via cams, so as to impart to the pistons a reciprocating movement, and a closed hydraulic system connecting cylinders at all pistons with a hydraulic line containing check-valves. Oil is supplied to the system with a pump and may be removed from the system via an overflow valve.

Abstract: A coupling device with two parts which are coaxially rotatable relative to one another, comprising a friction coupling whose friction plates are alternately connected to each of the rotatable parts. Further the coupling device comprises an actuating device for the friction coupling, which comprises an annular chamber formed in one of the rotatable parts and containing a highly viscous fluid. A rotational chamber is arranged in the annular chamber and is drivingly connected to the other one of the rotatable parts. The actuating device, when the rotatable parts rotate relative to one another, causes an increase in pressure for the purpose of loading the friction coupling.

Abstract: A coupling has two parts supported one inside the other, which are rotatable relative to one another around a common longitudinal axis. Together, the parts form a chamber filled with a highly viscous fluid and which is sealed by an axially movable piston. The coupling also includes a friction coupling with friction elements, having a spring assembly which is supported on a stop part and acting on a pressure plate. When the piston is in a position of rest, the friction elements of the friction coupling are held against a further stop part under pretension generated when the relative rotation begins. In the case of axial displacement, the piston displaces the pressure plate against the force of the spring assembly towards the first stop part, with there being provided an axial gap between the piston in a position of rest and a further stop part which is displaceable towards the first stop part.

Abstract: A hydraulic coupling including a multi-plate clutch assembly operably connecting two relatively rotatable members and an actuator assembly for actuating the clutch assembly in response to speed differentiation between the two rotary members. The actuator assembly includes a hydraulic pump, a piston disposed in a piston chamber, and a fluid distribution system including a first flow path for supplying hydraulic fluid from a sump to the hydraulic pump and a second flow path for supplying hydraulic fluid from the hydraulic pump to the piston chamber. Hydraulic pressure in the piston chamber controls the magnitude of the clutch engagement force exerted by the piston on the clutch assembly. The fluid distribution system further includes a third flow path between the piston chamber and a clutch chamber.

Abstract: A vehicle drivetrain differential (22) driven by a rotary drive member (24) rotatively drives a pair of rotary members (26, 28) and includes a housing (30) for containing hydraulic fluid and in which a hydraulic coupling (32) is received. A casing (34) of the hydraulic coupling has a ring gear (44) rotatively driven by the rotary drive member (24). A planetary gear set (36) of the bevel gear type is located within the casing (34) and includes a pair of bevel gears (124, 126) having associated spline connections (128, 130) to the pair of rotary members (26, 28), and the planetary gear set also includes planet gears 132 that revolve with the casing 34 and are meshed with both bevel gears to provide a differential gear action. A fluid inlet 58 and an outlet port 78 of the casing are provided with a gerotor type pump (48) provides pumping of hydraulic fluid into and out of the casing.

Abstract: A clutch mechanism is provided for a cooling fan of a size capable of fitting into the limited envelope available in an over-the-road diesel tractor. A compact housing has a belt drive input and an output connected to the fan hub. The housing includes a pressure chamber in fluid communication with a pressurized air supply and a controllable valve in the air supply line for regulating the pressure in the pressure chamber when the clutch must be operated. The air pressure actuates an internal piston to translate the clutch in a continuously variable manner between engaged and disengaged conditions.A small envelope clutch, having an outer diameter less than about 9.8 inches in diameter within the fan hub and less than about 6 inches under the belts and 7.3 inches overall so the housing may be positioned between the radiator and the engine, is capable of generating 150 foot-pounds of torque, running a 55 horsepower fan at 2100 rpm, and dissipating 10 horsepower of heat while in the slip mode.

Abstract: A drive force transmission apparatus includes a housing connected to one of two shafts that are rotatable relative to each other, a rotary shaft rotatably supported by the housing and connected to the other shaft, and a multiple disc clutch composed of a plurality of outer plates engaged with the housing in the rotational direction and a plurality of inner plates engaged with the rotary shaft in the rotational direction. The multiple disc clutch transmits rotational torque between the housing and the rotary shaft through frictional engagement between the outer plates and the inner plates. The apparatus also includes a pressure generation mechanism for generating a pressure corresponding to a rotational-speed difference between the housing and the rotary shaft and for applying the generated force to the multiple disc clutch via a piston.

Abstract: A hydraulic coupling arrangement used for a 4WD vehicle for imparting a drive torque of an engine to auxiliary drive wheels based on a first rotational difference between main and auxiliary drive wheels. A first rotary shaft is coupled to the main drive wheel and a second rotary shaft is coupled to the auxiliary drive wheel. A hydraulic pump of the coupling arrangement is adapted to be driven according to a second rotational difference between the first and second rotary shafts for generating an oil pressure corresponding to the second rotational difference. A clutch connects the first rotary shaft with the second rotary shaft based on the oil pressure generated by the hydraulic pump. A first oil passage extends to the clutch. First and second ports are formed in the hydraulic pump and function as inlet and outlet ports or vice versa based on the second rotational difference and a rotational direction of the first rotary shaft.

Abstract: A control valve (80) of a hydraulic coupling (32) controls pumping from a casing inlet port (58) by a hydraulic pump (48) through a casing outlet port (78) to control coupling between two rotary members such as by operation of a clutch (68). The casing (34) is connected to one of the rotary members while a pumping component embodied by an impeller (50) is connected to the other rotary member and meshed with an internal ring gear (54) having one more tooth than the number of impeller teeth to provide sufficient pumping capacity so that the pump can act as a brake while still having relatively constant pumping pressure. The control valve (80) includes an elongated valve element (82) mounted within a recess (98) to provide accurate control of its closure when the pumped hydraulic fluid reaches a predetermined pressure corresponding to a predetermined extent of relative rotation between the two drivetrain members.

Abstract: A coupling assembly has a friction coupling with friction plates alternately connected to respective ones of first and second coaxial parts which are rotatable relative to one another. A hydraulic actuating device for actuating the friction coupling has an annular chamber formed in one of the first and second parts. The annular chamber is defined by an axially movable piston which acts on the friction plates and containing a conveyor member for effecting fluid shear. The conveying member is connected to the other of the first and second parts. The annular chamber receives a highly viscous fluid, such that a pressure build up is generated to increase torque transmission between the first and second parts. The annular chamber is connected to a compensating chamber with a variable volume force for the highly viscous fluid. The compensating chamber is formed by an axially open annular groove and an axially movable annular element sealing said annular groove.

Abstract: A hydraulic fan coupling comprises a hermetically sealed case that is driven by the engine. The case is made of metal. Fan blades made of resin are molded onto elongated outer portions of the case.

Abstract: In the control system of an automatic transmission for a motor vehicle wherein power delivered from an engine is transmitted to a gear shift mechanism through a damper and then transmitted from the gear shift mechanism to driving wheels through a starting clutch, when an engine speed detected by engine speed sensor (in FIG. 1) is not higher than a predetermined value in the engine starting operation, an engageable element (in FIG. 1) constituting the gear shift mechanism is released, and when the engine speed is higher than the predetermined value, the engageable element is brought into engagement, thereby to alter the resonance point of a rotary system including the damper and to prevent the damper from resonating, so that a vibration of large amplitude does not occur in the engine starting operation.

Abstract: A clutch mechanism is provided for a cooling fan of a size capable of fitting into the limited envelope available in an over-the-road diesel tractor. A compact housing has a belt drive input and an output connected to the fan hub. The housing includes a pressure chamber in fluid communication with a pressurized air supply and a controllable valve in the air supply line for regulating the pressure in the pressure chamber when the clutch must be operated. The air pressure actuates an internal piston to translate the clutch in a continuously variable manner between engaged and disengaged conditions.A small envelope clutch, having an outer diameter less than about 9.8 inches in diameter within the fan hub and less than about 6 inches under the belts and 7.3 inches overall so the housing may be positioned between the radiator and the engine, is capable of generating 150 foot-pounds of torque, running a 55 horsepower fan at 2100 rpm, and dissipating 10 horsepower of heat while in the slip mode.

Abstract: A method and device for speed control of a friction clutch in a drive unit having a drive engine and in which the friction clutch includes at least two clutch parts that can be pressed together for purposes of torque transfer. The first clutch part is coupled at least indirectly to the drive engine and the second clutch part can be coupled to the drive engine via the first clutch part. The contact force for the clutch parts required for torque transfer is automatically applied hydraulically at least on achieving the idling speed of the drive engine by rotational pressure of a rotating ring of hydraulic fluid.

Abstract: A supplemental pressurized hydraulic supply (103) provides control of a hydraulic coupling (32a,32b,32c) that normally operates in response to differential rotation between a pair of rotary members (26,28) to provide actuation of a clutch (68) that couples the pair of rotary members. A rotary seal assembly (104) of the supply (103) feeds pressurized hydraulic fluid to the coupling to provide supplemental actuation of the clutch (68) that is normally actuated by hydraulic fluid from a hydraulic pump (48) that operates in response to the differential rotation between the pair of rotary members. In one embodiment, the hydraulic coupling (32a) also includes a differential gear set (36). A further embodiment of the hydraulic coupling (32b) includes a clutch (68) having a pair of clutch packs (69) that can be individually actuated by the supplement pressurized hydraulic fluid supply (103).

Abstract: A system for controlling a four-wheel drive for a motor vehicle comprises a drive mode switch for detecting a drive mode of the motor vehicle selectable between a two-wheel drive mode and a four-wheel drive mode. The four-wheel drive mode is selectable between a direct-coupled four-wheel drive mode. A an auto four-wheel drive mode, a controller controls the distribution of traction between main and secondary driving wheels. A traction transmission train distributes traction between the main and secondary driving wheels. The traction transmission train has an oil pressure supply system having a friction clutch and a solenoid.

Abstract: A power take off (PTO) clutch control system for an agricultural tractor is disclosed herein. The PTO clutch is a hydraulic clutch which is operated by a proportional valve capable of pressurizing the clutch with hydraulic fluid at a pressure related to the pulse width of a pulse width modulated (PWM) control signal applied to the valve. The PWM signal is produced by a controller which monitors the input shaft speed and the output shaft speed. A first control signal is applied to the valve when both the input and output shaft speeds are greater than zero. A second control signal is applied to the valve when the input shaft speed has decreased by a predetermined amount and the output shaft speed is substantially zero.

Abstract: A force or torque transmitting apparatus which transmits torque from the output element of a prime mover to the input element of a transmission or another driven unit in a motor vehicle by way of a hydrokinetic torque converter and/or by way of a lockup clutch. When the vehicle embodying the apparatus is coasting, the housing of the torque converter is engaged only by the friction lining on the axially movable piston of the lockup clutch when the latter is engaged, either entirely or with slip. Thus, it is not necessary to provide one or more thrust bearings between the piston of the lockup clutch and the housing of the torque converter.

Abstract: An automatic transmission system with a lock-up clutch for use with an engine includes an automatic transmission having an input shaft and an output shaft. A torque converter with a lock-up clutch is provided between the input shaft of the automatic transmission and an output shaft of the engine. A first device calculates a measure of time-domain variation in the rotational speed of the output shaft of the engine. A second device detects whether or not the measure of time-domain variation in the rotational speed of the output shaft of the engine exceeds a predetermined threshold value. A third device changes the condition of the lock up when the second device detects that the measure of time-domain variation exceeds the threshold value. A similar system is operable when the second device calculates a measure of time-domain variation in the rotational speed of the output shaft or the input shaft of the automatic transmission.

Abstract: A control valve (80) of a hydraulic coupling (32) controls pumping from a casing inlet port (58) by a hydraulic pump (48) through a casing outlet port (78) to control coupling between two rotary members such as by operation of a clutch (68). The casing (34) is connected to one of the rotary members while a pumping component embodied by an impeller (50) is connected to the other rotary member and meshed with an internal ring gear (54) having one more tooth than the number of impeller teeth to provide sufficient pumping capacity so that the pump can act as a brake while still having relatively constant pumping pressure. The control valve (80) includes an elongated valve element (82) mounted within a recess (98) to provide accurate control of its closure when the pumped hydraulic fluid reaches a predetermined pressure corresponding to a predetermined extent of relative rotation between the two drivetrain members.

Abstract: Tandem rear axle assembly for motor vehicles, especially trucks. The tandem rear axle assembly herein does not employ an inter-axle differential. Instead, torque is transmitted from a motor drive shaft to a longitudinally extending through shaft, which may drive a differential for a rearward rear axle. A forward rear axle is selectively engaged or disengaged, as driving conditions require, by a disk-type friction clutch or clutch pack. The clutch pack may be actuated by an actuator assembly which includes sensors for determining the rotational speeds of the two rear axles, and a computer controlled unit or signal generator for generating an output signal when the difference in rotational exceeds a predetermined limit. The output signal actuates, for example, by air pressure, a piston which compresses the clutch pack so as to engage the clutch and thereby transmit torque to both the forward and rearward rear axles simultaneously. The clutch may be manually actuated if desired.

Abstract: A hydrokinetic torque converter has a rotary housing which is connectable to the crankshaft or camshaft of a combustion engine in a motor vehicle to drive the input shaft of the transmission. The housing confines a turbine, a pump, a stator (if necessary) and a lockup clutch between a radially extending wall of the housing and the turbine. A piston of the lockup clutch is movable in the axial direction of the housing and defines a first fluid-filled compartment with the turbine as well as a second fluid-filled compartment with the wall of the housing. The force which is required to engage, to partially disengage or to fully disengage the lockup clutch is reduced by the provision of one or more profiles on the piston and/or on a friction disc of the lockup clutch which extends or extend into the adjacent compartment or compartments to influence the speed of circulation of fluids in the respective compartments and/or the fluid pressures acting upon opposite sides of the piston.

Abstract: A process is proposed to regulate a continuously variable transmission (2) with a clutch (9). The slip torque of the clutch is cyclically or anticyclically determined and the intensity of the clutch thrust is compared with a characteristic curve. This comparison sets a correction value used for modifying the characteristic curve.

Abstract: A clutch mechanism for a cooling fan of a size capable of fitting into the limited envelope available in an over-the-road diesel tractor. A compact housing has a belt drive input and an output connected to the fan hub. A wet clutch is included within the housing lubricated by oil from the engine lubrication system. The housing includes an internal positive displacement booster pump cooperating with a controllable valve in the oil return line to the engine sump. When it is desired to operate the clutch, the valve is controllably closed to restrict flow from the clutch mechanism to the engine sump line. The positive displacement pump thereupon causes an increase in pressure in a pressure chamber in the housing, which acts on an internal piston to translate the clutch in a continuously variable manner between engaged and disengaged conditions.

Abstract: A hydrokinetic torque converter has a rotary housing which is connectable to the crankshaft or camshaft of a combustion engine in a motor vehicle to drive the input shaft of the transmission. The housing confines a turbine, a pump, a stator (if necessary) and a lockup clutch between a radially extending wall of the housing and the turbine. A piston of the lockup clutch is movable in the axial direction of the housing and defines a first fluid-filled compartment with the turbine as well as a second fluid-filled compartment with the wall of the housing. The force which is required to engage, to partially disengage or to fully disengage the lockup clutch is reduced by the provision of one or more profiles on the piston and/or on a friction disc of the lockup clutch which extends or extend into the adjacent compartment or compartments to influence the speed of circulation of fluids in the respective compartments and/or the fluid pressures acting upon opposite sides of the piston.

Abstract: An axle drive for distributing torque from a propeller shaft to two axle shafts of a motor vehicle axle which is not permanently driven, having two torque transmitting friction couplings which are arranged in the coupling housing and intended to drive the axle shafts, and having two actuating devices for the two friction couplings. There is provided a common pump housing which is non-rotatably connected to the coupling housing and which contains two symmetrically and axially movably arranged pistons delimiting one end of pressure chambers each filled with a highly viscous fluid and connected to a reservoir. Pumping and control members are arranged opposite the pump housing between two end positions so as to be rotatable to a limited extent. The pressure chambers each contain conveying members which are each non-rotatably connected to one of the axle shafts. Rotational faces of a conveying member, together with counter-faces of the pumping and control member, constitute at least one sealed shear channel.

Abstract: A hydrokinetic torque converter has a rotary housing which is connectable to the crankshaft or camshaft of a combustion engine in a motor vehicle to drive the input shaft of the transmission. The housing confines a turbine, a pump, a stator (if necessary) and a lockup clutch between a radially extending wall of the housing and the turbine. A piston of the lockup clutch is movable in the axial direction of the housing and defines a first fluid-filled compartment with the turbine as well as a second fluid-filled compartment with the wall of the housing. The force which is required to engage, to partially disengage or to fully disengage the lockup clutch is reduced by the provision of one or more profiles on the piston and/or on a friction disc of the lockup clutch which extends or extend into the adjacent compartment or compartments to influence the speed of circulation of fluids in the respective compartments and/or the fluid pressures acting upon opposite sides of the piston.

Abstract: The proposal is for a process for controlling and regulating the load take-up in an automatic transmission. To this end, in an overlapping gear change, the torque take-up of a first engaging clutch is derived from feedback values. The feedback values control or regulate the operation of a second disengaging clutch.

Abstract: A power take off (PTO) clutch control system for an agricultural tractor is disclosed herein. The PTO clutch is a hydraulic clutch which is operated by a proportional valve capable of pressurizing the clutch with hydraulic fluid at a pressure related to the pulse width of a pulse width modulated (PWM) signal applied to the valve. The PWM signal is produced by a controller which monitors the output shaft speed and movement to determine the time at which the shaft begins movement. Prior to shaft movement, the PWM signals control the proportional valve to prevent clutch engagement when the hydraulic fluid in the system is cold, clutch engagement has not occurred in a timely fashion and the operator has left the seat of the tractor.

Abstract: A combined transmission assembly and monitoring system for indicating the operating condition of the transmission assembly includes a transmission assembly having an input shaft, an output shaft, and a plurality of components for connecting the output shaft for rotation at a predetermined speed relative to the input shaft, a sensor attached to a portion of the transmission assembly, the sensor being responsive to vibration of the portion of the transmission assembly for generating signals indicative of the sensed vibration, and a controller for receiving the signals from the sensor and generating an indication of the operating condition of the transmission assembly based on the vibration of the portion of the transmission assembly. Preferably the sensor is adapted to detect both the frequency and magnitude of vibration of the transmission assembly and to generate signals indicative of the sensed frequency and magnitude of vibration.

Abstract: A modular speed sensor for sensing the speed of a rotating body is disclosed. The sensor includes a sensor housing comprising an elongate tube and a sensor housing body. A hall effect sensor is installed in the elongate tube and wires connected to the hall effect sensor extend through the tube and connect to a wire interconnect board installed within the sensor housing body. A compression grommet is provided to hold the wire interconnect board within the sensor housing body. Preferably, a second set of wires extend through holes in the compression grommet and connect to the wire interconnect board. The second set of wires can then be connected to a control circuit or other device to read a speed signal from the modular speed sensor.

Abstract: A power take off (PTO) clutch control system is disclosed herein. The PTO clutch is a hydraulic clutch which is operated by a proportional valve capable of pressurizing the clutch with hydraulic fluid at a pressure related to the pulse width of a pulse width modulated (PWM) signal applied to the valve. The PWM signal is produced by a controller which monitors the input and output shaft speeds to determine the pulse width of the PWM signal. The clutch control also includes a brake which inhibits rotation of the clutch output shaft when the clutch is disengaged. The brake is operated by an on/off valve which is also controlled by the controller.

Abstract: A power take off (PTO) clutch control system is disclosed herein. The PTO clutch is a hydraulic clutch which is operated by a proportional valve capable of pressurizing the clutch with hydraulic fluid at a pressure related to the pulse width of a pulse width modulated (PWM) signal applied to the valve. The PWM signal is produced by a controller which monitors the output shaft speed and movement to determine the time at which the shaft begins movement. Prior to shaft movement, the PWM signals control the proportional valve to engage the clutch slowly and smoothly to avoid producing unacceptably high torques in the PTO shaft connected to the clutch during clutch engagement.

Abstract: A fluid clutch includes a rotatably driven shaft. A closed casing is rotatably mounted on the shaft by bearings. The casing includes an oil basin chamber and a torque transfer chamber. A driving disc is rigidly mounted to the shaft and in the torque transfer chamber. An exhaust passage extends from an outer position in the torque transfer chamber to the oil basin chamber. A dam in the torque transfer chamber urges oil into the exhaust passage and to the oil basin chamber. A pump is disposed between the oil basin chamber and the torque transfer chamber and is operative to urge oil from the oil basin chamber downstream into the torque transfer chamber. A valve is operative to selectively open or close access to the pump in accordance with sensed temperature. Thus, the dam and exhaust passage urge oil from the torque transfer chamber to prevent accompanying rotation. However, the pump urges oil into the torque transfer chamber in accordance with cooling needs.

Abstract: A device for transmitting torque between two rotatable, coaxial shaft members (1, 2) in a stationary housing (4) has a clutch (11, 12) engageable to counteract differential rotational speed between the shaft members. A hydraulic clutch piston (14) is arranged to engage the clutch, and a hydraulic pump arrangement (1', 18-21, 11", 14-17), driven by the speed differential between the two shaft members, creates a hydraulic pressure on the clutch piston. The hydraulic pump arrangement includes a supply piston (18) and the clutch piston. Rollers (17, 21) are rotatable with one of the shaft members (2) and engage the other of the shaft members (1) via cams (1', 11"), which are angularly offset in relation to each other, so as to impart to the pistons a reciprocating movement at the differential rotational speed between the shaft members.

Abstract: A torque coupling device for use as, for example, a so-called center differential provided between front and rear road wheel axles of a four-wheeled vehicle comprises a cup-shape front housing, a rear housing closing an open end of the front housing, a rotational shaft co-axially rotatably supported by the front and rear housings therewithin, and a clutch disc assembly interposed within the front housing between an axial inner end of the front housing and an axial inner end of the rear housing. The initial clearance in axial direction between the clutch assembly and the inner ends of the front and rear housings is tuned so that when the relative rotation between the housings and said rotational shaft causes a certain temperature difference between the housing and the clutch assembly, the difference in thermal expansion between the front housing and the clutch assembly brings clutch discs of the clutch assembly into friction contact to transmit a rotational torque between the housings and the rotational shaft.

Abstract: A torque split control apparatus for use with an automotive vehicle including an engine for producing a drive. The automotive vehicle is supported on a pair of primary drive wheels and a pair of secondary drive wheels. The drive is transmitted from the engine to the primary drive wheels and to the secondary drive wheels through a torque distributing clutch capable of varying a torque transmitted to the secondary drive wheels. A control torque is calculated based upon a difference between the primary and secondary drive wheel rotational speeds. The control torque is transmitted through the torque distributing clutch to provide a desired turning characteristic to the vehicle. At least one vehicle condition dependent torque, which is dependent on a specified vehicle operating condition, is calculated. Vehicle operating conditions are monitored to produce a command signal when a 4WD control is demanded.