Abstract: A clutch arrangement for a multi-spindle machine includes a starting clutch 12 and a machine brake clutch 14 positioned on a starting clutch drive shaft 16. A high speed clutch 18 and a snubbing clutch 22 are positioned on a long worm drive shaft 20. All clutches are pneumatically operated by solenoid valves 40, 42, 44 and 46 and electrically actuated by electrical circuit 60. When the multi-spindle machine shifts from a high speed to a low speed, the present invention activates the machine brake clutch 14 and snubbing clutch 22 for a predetermined time period to cause the drive train gears to slow down allowing synchronous meshing with the low speed drive train of the multi-spindle machine to enable a reduction in machine cycle time.

Abstract: A damper for use with a hydraulic actuator of the type including a master cylinder and a slave cylinder with a conduit interconnecting the outlet of the master cylinder and the inlet of the slave cylinder. The damper is positioned in the conduit between the master cylinder and the slave cylinder and includes a housing member defining a chamber opening in one face of the housing member and a mounting bracket plate. The mounting bracket plate includes a housing portion corresponding in size and configuration to the one face of the housing member and is positioned against the one face of the housing member to coact with the housing member to seal the chamber. The bracket plate further includes a bracket portion extending outwardly from the housing portion in the form of mounting arms which are utilized to facilitate mounting of the damper to a fixed vehicle structure.

Abstract: A coupling control device for a coupling has at least one valve for controlling at least one coupling, and at least one throttle arrangement arranged between the at least one valve and the at least one coupling.

Abstract: A method for controlling operation of a hydraulic valve having a magnet fixed to a displaceable spool, a sensor producing a signal responsive to the sensed intensity of a field produced by the magnet representing the position of the spool in the valve spool, the method comprising producing from the signal a time series record of the position of the spool; determining the desired position of the spool, producing a error signal from the difference between actual and desired spool position, determining a compensated correction error, producing a commanded control pressure signal to change the magnitude of control pressure supplied to the valve, and changing the position of the spool in response to the control pressure signal.

Abstract: An operation device for a friction clutch arranged in the drive train of a motor vehicle. The operation device includes a positioning servo arrangement with a pneumatic power cylinder arrangement. The pneumatic power cylinder arrangement acts on a clutch release sleeve arrangement. The positioning servo arrangement can be operated with a control valve that is connected to a pneumatic source depending on a command variable representing a desired position and an actual variable representing the axial position of the clutch release sleeve arrangement. The pneumatic power cylinder arrangement is arranged inside of the bell-shaped housing and the control valve is arranged outside of the bell-shaped housing or the bell-shaped housing is arranged at least partially inside of the bell-shaped housing, but is accessible from the outside and/or can be removed when the bell-shaped housing is attached to the combustion engine.

Abstract: By determining the abrasion of a gear clutch during the operation of a construction machine and ascertaining the present abrasion state, it is possible to systematically predict the replacement time of a clutch disc and also to ascertain the presence of an abnormally worn clutch disc.

Abstract: In one aspect of this invention, a fluid actuated clutch is disclosed. The fluid actuated clutch is operatively connected to a control valve that is actuated by an electronic controller that receives a signal from an input mechanism, including a value for speed of an engine drive and a value of output speed for a torque converter. The method includes detecting a torque converter ratio which is the output speed of the torque converter divided by the engine drive speed, and detecting if there is at least one torque converter decrease exceeding a predetermined level and preferably detecting if there are at least two consecutive decreases in the torque converter ratio with at least one of the torque converter decreases exceeding a predetermined minimum level. This condition represents the end-of-fill point for the fluid actuated clutch.

Abstract: A pushrod assembly for use in association with a vehicle clutch control system of the type including a slave cylinder having an output member adapted for control of the clutch mechanism of the vehicle, a master cylinder for supplying hydraulic fluid to the slave cylinder, and a clutch control pedal assembly for actuating the master cylinder via the pushrod assembly. The pushrod assembly is connected at a forward end thereof to the master cylinder piston and is adapted for connection at a rearward end thereof to the clutch pedal arm and includes an isolator member of resilient material carried by the pushrod and interposed between the rearward pushrod end and the clutch pedal in a position to be resiliently distorted in response to movement of the control pedal in a release direction relative to the pushrod.

Abstract: A hydraulic pressure-control valve for controlling a pressure to be supplied to a frictional engaging element such as a start clutch in an automatic vehicle transmission, including a first pressure-regulating valve connected to a hydraulic pressure source and connected to the frictional engaging element through a second passage, and a solenoid for displacing the first-pressure-regulating valve.

Abstract: A clutch-actuated piston structure is provided for engaging and releasing a clutch engaging member 23 of a power disconnecting clutch 9. The clutch-actuated piston structure is especially useful in a torque converter. The clutch-actuated piston structure is powered by hydraulic oil from the torque converter or other device. The hydraulic oil is discharged from the torque converter through one or more oil paths 47. The clutch-actuated piston structure has a piston 25 movably coupled to a hydraulic chamber structural member 26. The piston 25 and the hydraulic chamber structural member 26 form therebetween a first hydraulic chamber A and a second hydraulic chamber B. The first hydraulic chamber A receives the hydraulic oil from the torque converter or other device. The second hydraulic chamber B is connected to the first hydraulic chamber A via a diaphragm D, which restricts the flow of hydraulic oil from the first hydraulic chamber A to the second hydraulic chamber B.

Abstract: A control system for an engine transmission provided with a coupling mechanism for engaging or disengaging coupling of the transmission. The control system has one or more valves movable between two positions for controlling engagement and disengagement of the coupling mechanism. The valves are connected to an automatic control unit which has an intermittent signal supply trigger for supplying an intermittent pulsed signal to the valves, thereby providing an intermittent movement of the valves between the two positions.

Abstract: A multiple disk clutch includes a clutch drum having an interior surface with a plurality of spline grooves, a servo piston, a clutch plate with splines engaged within the spline grooves, and a cushion plate, with splines engaged within the spline grooves, arranged between the clutch plate and the servo piston. The splines of the clutch plate and those of the cushion plate are engaged within different spline grooves so that the splines of the clutch plates and those of the cushion plate do not contact each other when the clutch is engaged by a load imposed by operation of the piston.

Abstract: A hydraulic pressure-control valve for controlling a pressure to be supplied to a frictional engaging element such as a start clutch in an automatic vehicle transmission, including a first pressure-regulating valve connected to a hydraulic pressure source and connected to the frictional engaging element through a second passage, and a solenoid for displacing the first-pressure-regulating valve.

Abstract: In one aspect of this invention, a fluid actuated clutch is disclosed. The fluid actuated clutch is operatively connected to a control valve that is activated by an electronic controller that receives a signal from an input mechanism. The system and method includes detecting an instantaneous clutch slip and detecting when the instantaneous clutch slip is less than an average of a predetermined number of cycles of instantaneous clutch slip that is divided by a predetermined factor. This condition represents the end-of-fill point for the fluid actuated clutch.

Abstract: A throttle device for the directionally-dependent influencing of the flow velocity of the fluid in hydraulic actuator systems, in particular of friction clutches in motor vehicles, with a throttle located between a master cylinder and a slave cylinder in the hydraulic system. The throttle is formed by a base body with at least one through hole, which through hole can be at least partly closed by a rubber-elastomer disc. The rubber-elastomeric disc is located on the side of the base body facing the slave cylinder, which disc radially overlaps a through hole, which through hole can be at least partly closed.

Abstract: A control system and method for operating the solenoid valves for controlling the supply of hydraulic fluid to a hydraulic actuator is described. The system and the method involves initially applying a first, increasing linear pressure up to a predetermined magnitude and then holding the pressure at that level for a period of time. This predetermined magnitude is equal to the amount of pressure required to cause initial movement of the piston. By holding the pressure level at a plateau for a period of time, the initial movement of the piston is accomplished in a smooth manner. This period of time is relatively short, typically less than one second. Thereafter, the system and the method involve operating the solenoid valves so as to apply a second, increasing linear pressure up to a predetermined final magnitude.

Abstract: A fluid-operated system which can supply a pressurized fluid (e.g., oil) to one or more adjustable consumers (such as a clutch and/or a transmission) in a motor vehicle. The system employs one or more fluid pressurizing pumps and/or accumulators and an arrangement of valves in a path for pressurized fluid from the pressurizing unit(s) to the consumer(s). The valves can vary the fluid pressure in dependency upon at least one variable (such variable can be selected by a control unit in conjunction with an actor). In accordance with one presently preferred embodiment, the valves can cooperate with one or more flow restrictors to impart to the fluid in the path a first pressure within a first range of varying pressures as a first function of the at least one variable, and a second pressure within a second range of varying pressures as a different second function of the at least one variable. One of the valves can be embodied in or located outside of the mobile valving element and/or housing of another valve.

Abstract: A clutch engagement control has a flow regulating valve to control the engagement timing of the clutch. The regulating valve responds to a flow signal to reduce the fluid flow rate through the valve after the clutch apply piston has taken up the clutch free running clearance. The regulating valve has a control area communicating with a venturi between the regulating valve and the apply piston such that a flow rate signal is present at the control area.

Abstract: In a vehicle having a power shift transmission engageable in a plurality of forward gear ratios by engaging and disengaging first and second fluid clutches with a fluid from a fluid supply, a manifold apparatus for measuring a pressure of the fluid and simultaneously filling the first and second clutches with the fluid supply having a first clutch fill valve fluidly coupled to the first clutch to control the flow of the fluid to the first clutch; a second clutch fill valve fluidly coupled to the second clutch to control the flow of the fluid to the second clutch; a manifold fluidly coupled to the first and second clutch valves to conduct the fluid from the fluid supply to the first and second clutch valves; a first flow restrictor disposed between the manifold and the fluid supply to restrict the flow of the fluid from the fluid supply to the manifold; and a pressure transducer fluidly communicating with the manifold to generate a signal representative of the pressure of the fluid within the manifold, where t

Abstract: A facing surface of a clutch piston is previously moved to a position just before it abuts against an inner surface of a torque converter cover, or a position in which it extremely slightly abuts against the inner surface of the torque converter cover by outputting an initial engage pressure YMIN set in accordance with a vehicle speed and the like only for a predetermined time TMPS prior to the start of engagement of a lockup clutch. When the engagement of the lockup clutch is started, the engage pressure is gradually increased. When the engage pressure approaches a target pressure set in accordance with the target speed ratio, a feedback control of the engage pressure is carried out such that the actual speed ratio of the torque converter is converged to the target speed ratio. Thus, when the lockup clutch of the torque converter is brought into an engaged state, the responsiveness can be enhanced while preventing the generation of a shock.

Abstract: A changeover valve (13) connected to a shift valve unit (12) via four oil passages L3-L6, and two pressure regulating valves (14.sub.1, 14.sub.2) are provided. At speed changing when the changeover valve (13) is in a first (right) position, an off-going hydraulic clutch is connected to oil passage L3 to control its pressure drop by the pressure regulating valve (14.sub.1) and an on-coming hydraulic clutch is connected to L5 to control its pressure rise by the pressure regulating valve (14.sub.2). After completion of the speed changing, the changeover valve (13) is switched to a second (left) position. At speed changing when the changeover valve (13) is in the second position, an on-coming hydraulic clutch is connected to L4 to control its pressure rise by the pressure regulating valve (14.sub.1) and an off-going hydraulic clutch is connected to the L6 to control its pressure drop by the pressure regulating valve (14).

Abstract: A powershift transmission includes a plurality of hydraulically operated clutch packs which are selectively engaged and disengaged to enable various gear ratios. A control circuit for such a transmission includes a system pressure source, a fluid reservoir, a control gallery, a plurality of control valves and a plurality of latching valves. Each control valve and each latching valve is connected with a corresponding one of the clutch packs, and is communicated with each other, with the system pressure source, with the reservoir and with the control gallery. The control valves, latching valves and the control gallery cooperate to prevent pressurization of any one of the clutch packs before all the clutch packs are filled with hydraulic fluid. The control valves and the latching valves also cooperate to maintain disengaged clutch packs at reservoir pressure, and to maintain engaged clutch packs at system pressure.

Abstract: This invention includes an apparatus for calibrating fluid clutch fill times including a valve, a clutch connected to the valve, a fluid supply connected to the valve, a pressure transducer connected between the fluid supply and the valve, and a processor adapted to control the valve, read the pressure transducer, and calculate the time required to fill the clutch. The invention further includes a method for adaptively controlling clutch engagement and disengagement in a clutch control system including signalling a first clutch valve to fill a clutch, measuring the time required to fill the clutch, signalling a second clutch valve to empty a second clutch, and saving the time value.

Abstract: A hydraulic control has a valve body assembly in which a plurality of control valves are contained. The valve body has separate structures which are secured together by fasteners. Separator plates are positioned between the structure levels to establish flow passages and sealing elements between fluid passages in the separate structures. The separator plate has two conical valve seats formed therein which cooperate with two pintle valves to control the flow of hydraulic fluid to and from a ratio controller within a power transmissions.

Abstract: A pressure-control device is used to affect the engaging behavior of powershift clutches in a powershift gear with a control valve cooperating with a damping device, as a pressure-control valve (2), by which the pressure cycle can be set on engaging the clutch concerned. The pressure in a chamber (C3), between a displacement piston (4) and a pressure-control piston (3), can be controlled via a first switching valve (11) switched by a magnetic valve (10). A chamber (C2) behind the displacement piston (4) can be exhausted, via a second switching valve (14) switched by the same magnetic valve (10), whereby the pressure-control piston (3) is held in its initial position to release the full valve aperture cross section from the pressure line (1) to the clutch line (7).

Abstract: There is disclosed a motor vehicle having a set of front wheels, a set of rear wheels, an engine, and a transmission driven by the engine and having a transmission output shaft. The motor vehicle further has a transfer including a variable torque trasmitting (VTT) clutch for varying a distribution of torque between the set of front wheels and the set of rear wheels depending upon degree of engagement thereof. A clutch activating pressure is generated and transmitted to the VTT clutch under the control of a mode selector valve.

Abstract: Disclosed is a modulating hydraulic circuit for controlling a clutch such as the clutch on a power takeoff (PTO) shaft. The circuit includes a throttling valve having (a) an inlet port for receiving hydraulic fluid from a source, and (b) a discharge port connected to the clutch. The discharge port is also connected to an accumulator which is at an accumulator pressure. The discharge port and the clutch are at a pressure generally proportional to the accumulator pressure. As accumlator pressure rises at a controlled rate, the clutch is progressively engaged. Optionally, the circuit includes a brake control valve for "softly" disengaging a PTO shaft brake as the accumulator pressure rises. A method for controlling the clutch includes flowing hydraulic fluid through hydraulic lines to a throttling valve connected to an accumulator and to the clutch, increasing pressure in the lines and progressively engaging the clutch.

Abstract: An automatic transmission control system includes a frictional engagement element formed of alternating radially inner and outer thin plates for selectively transmitting a torque. The control system further includes a hydraulic servo having a piston which selectively engages/disengages the frictional engagement element responsive to an oil pressure. An electric characteristic detector detects (monitors) an electric characteristic which changes with change in the apply force of the frictional engagement element; and an apply force control unit controls the apply force of the frictional engagement element. The electric characteristic detector includes a signal generator for generating an electric signal in accordance with the relative positions of two electrically conductive members, which move as the frictional engagement element is engaged/disengaged.

Abstract: A rotating clutch has a feed passage that is maintained at a predetermined pressure by a backfill control valve during periods of clutch disengagement when the clutch apply chamber is not pressurized. The valve is slidably disposed in a stationary housing in fluid communication between a pressure source and the apply chamber of the clutch. When the pressure source is reduced below a predetermined level, the valve is positioned to prevent the pressure in the passage from decreasing below the predetermined level while exhausting the clutch apply chamber. When clutch actuation is desired, the pressure source increases to open the backfill valve. With the valve opened by pressure, the fluid pressure is supplied to the clutch apply chamber thereby applying the clutch. The valve is positioned in the housing to admit pressurized fluid from the source to the clutch apply chamber while disconnecting the apply chamber from exhaust when clutch apply is required.

Abstract: An electronically controlled clutch pedal dashpot driveline torque limiter utilizes a solenoid to regulate the apply rate of a vehicle master clutch based on current vehicle operating conditions such as engine speed, transmission input speed, and clutch pedal release rate. The present invention allows greater control authority of master clutch apply rates to reduce or eliminate the incidence of engine stall and excessive slipping of the master clutch.

Abstract: A reversing transmission for marine propulsion units or the like. The reversing transmission includes a multiple disc clutch assembly that is cooperative with a pair of bevel gear and clutch assemblies. These bevel gear and clutch assemblies are made up of a two-part construction each comprised of a bevel gear and a tubular sleeve that is affixed to the bevel gear and which carries a series of clutch plates. A clutch actuating piston is also incorporated that has a tapered end face so as to improve and make smoother the clutch engagement.

Abstract: A press includes a drive system which includes a brake and a clutch operated by fluid pressure. The brake and clutch control the movement of a crankshaft in relation to a flywheel. A unique control system supplies the pressurized fluid for operation of the brake and clutch. The unique control system includes a pressure relief valve for defining a maximum fluid pressure and a plurality of valve modules which each define a specific fluid pressure. Each valve module is selectively movable between a relief condition and a blocked condition. Thus, by selectively operating the valve modules, it is possible to select the fluid pressure being supplied to the brake and clutch.

Abstract: A control method/system for controlling the operation of a pneumatically actuated vehicular master clutch (20) is provided. A position sensor (76) senses the position of an actuating piston (82) in a cylinder (80), and the piston is controlled to move to and remain at an axial position (DOP, EOP) offset stop members (88, 90) in at least one of the fully disengaged and engaged positions of the clutch.

Abstract: A hydraulic control system for displacing a synchronizer into engagement with a rotating gear in a gearbox includes a hydraulic piston/cylinder unit mechanically coupled to the synchronizer, an electrically controllable pressure regulating valve for supplying hydraulic fluid to the piston/cylinder unit and an electrical control circuit acting on the pressure regulating valve to vary the pressure of the hydraulic fluid supplied to the piston/cylinder unit. In order to effect a rapid and smooth engagement of the synchronizer, the control circuit acts to increase the pressure of the hydraulic fluid supplied to the piston/cylinder unit progressively.

Abstract: A hydraulic pressure system for a frictional engaging element such as clutches for a vehicle automatic transmission. The engagement state of the clutches is detected from the clutch slip rate, and the desired change rate of the rotational speed of the transmission input shaft (the main shaft rotational speed) during the gearshift operation period is varied based thereon. The hydraulic pressures supplied to the clutches are controlled for bringing the actual rotational speed change rate to the desired value. Since the clutch engagement state can therefore be controlled based on the desired value, irrespective of the temperature of the oil (ATF) and aging of the clutches, it is at all times possible to secure optimum gearshift characteristics and to avoid the occurrence of gearshift shock.

Abstract: A hydraulic pressure supply system for a variable torque transfer of a four-wheel drive vehicle in which a driving-torque distribution ratio between front and rear road wheels is varied by adjusting a clutch pressure applied to a variable torque clutch assembled in said transfer, comprises an oil pressure source supplying a pressurized working fluid into a hydraulic line, at least one pressure regulating valve fluidly connected to the line for decreasingly regulating the pressurized working fluid at a predetermined clutch pressure, and a directional control valve fluidly connected to the pressure regulating valve for directing the clutch pressure to a transfer clutch. An electromagnetic solenoid valve is provided for controlling the pressure regulating valve and the directional control valve for selectively supplying one of a stand-by pressure and a clutch engaging pressure to the transfer clutch.

Abstract: A torque converter having a lockup mechanism makes it possible to positively and forcibly suppress the frictional heat and others generated on the frictional surfaces of the lockup clutch and its counterpart while the lockup clutch is in operation, particularly in a slipping state. Hence, the life of the lockup clutch or that of the torque converter as a whole is prolonged. In this torque converter having the lockup mechanism, a hydraulic control mechanism is provided for maintaining the difference of pressure substantially at a constant level and changing the flow rate of a fluid to be supplied to the frictional surface of the lockup clutch in order to control the slipping state of the lockup clutch. Oil grooves are cut on the frictional member of the lockup clutch.

Abstract: The thermal load on a transmission clutch, which is generated when a shift between forward and reverse is made, can be reduced and a shock from a speed change can be eliminated. To these ends, as soon as a speed change signal is received (step 150), an all clutch control system (ACC) is actuated to set a target acceleration in terms of the amount of control (steps 152, 154). Then, it is determined whether the speed change involves a shift between forward and reverse (FR speed change) (step 156). If the speed change is found to be the FR speed change, then it is further determined whether the vehicle speed V is larger than a reference value V.sub.O (step 158); if the vehicle speed is larger than the reference value, then the oil pressure for operating a steering brake is read from preestablished map data (step 160), and the steering brake is operated by the oil pressure which has been read (steps 162, 164). After that, the ACC control program goes back to step 156.

Abstract: A pulse width modulated solenoid valve for control of hydrodynamic torque converters of automatic transmissions, comprising an electromagnetic switching element (11) and a valve body (12 ), wherein the valve body (12 ) has: an end (13 ) facing the switching element; an end (14 ) remote from the switching element; a control pressure chamber (15) for a fluid medium; a control spool (28) with at least one control groove (29a); a control pressure connection (20) to the control pressure chamber (15) for the fluid medium; at least one first pressure connection (22) connecting the control pressure chamber (15) to at least one outlet (21); at least one second pressure connection (24, 26) connecting at least one working chamber (16, 17) with at least one outlet (23, 25); at least one counter-pressure chamber (18) located at the opposite end of the valve body (12) to the control pressure chamber (15); at least one pressure connection (20, 22, 24, 26) being capable of being connected to at least one outlet (21, 23, 25)

Abstract: According to this invention, this is obtained by providing a sensor (18) on a clutch linkage (20) or master cylinder (117) to sense the force applied by the operator. The sensor (18) then actuates a valve (36) which provides pressure to a booster cylinder (28). The booster cylinder (28) is connected to the clutch release lever (26) in parallel with the clutch linkage (20) or slave cylinder (117), both of which transmit forces to operate the clutch.

Abstract: A regulator valve (14) includes a valve spool (30) biased in a valve chamber (32) by control pressure whose magnitude is determined by operation of a variable force solenoid (42), first and second control areas (28, 26) exposed to friction element pressure. A shift valve (16) includes a spool having multiple control lands (66, 68), the position of spool determined by the state of an on/off solenoid (70). The shift valve produces high and low hydraulic pressure operative to open and close line pressure or a vent to a hydraulically-activated clutch.

Abstract: A two stage electrohydraulic pressure control valve includes a pilot stage for providing regulated pressure at lower flows to a larger main stage that handles the higher control flows to and from a pressure applied clutch or pressure released brake. The regulated pressure from the pilot stage acts on an end of the main stage for controlling the position of the main stage. An energy storage device in the form of either an accumulator or a load piston device is connected to the end of the main stage to permit instantaneous independent movement of the main stage relative to the pilot stage. The energy storage device quickly provides for or accepts displaced fluid from the main stage much faster than the limited flow capacity and response time of the pilot stage. This permits the main stage to quickly adjust to flow changes to the clutch or brake with minimal change in pressure until the pilot stage can respond.

Abstract: A cutoff valve for pistons of hydraulic self-adjusting devices, comprising an essentially cylindrical through element (18), attached axially to the internal end of the rod (3) of the device (1), and a cutoff element (19), also essentially cylindrical, arranged coaxially with the rod (3) on which it slides with a tight fit. The through element (18) has through holes (23) through which the liquid fluid (F) contained within the main body (2) of the device (1) can flow. The cutoff element (19) has a cutoff joint (29), which can block the holes (23) of the through element (18), and a peripheral thickening (30) provided with a sealing joint or ring (33) and a number of channels (31) through which the liquid fluid (F) can flow freely. The cutoff valve can be used in the car industry.

Abstract: A bridging coupling is actuated by an annular piston to which the converter's internal pressure is applied on one side thereof in an opening direction and a closing pressure is applied in the closing direction. The closing pressure is controlled by a precontrolled regulating valve depending on the output pressure of the converter and on a control pressure that depends upon further operating parameters. With the coupling open, the closing pressure in the closing pressure chamber remains below the internal pressure of the converter by a specified value. This ensures that the bridging coupling responds quickly and can be precisely regulated within narrow tolerances. In addition, only relatively little power is needed for the regulation.

Abstract: A multi-speed power transmission has a fluid operated torque transmitting device, such as a clutch, which is selectively engaged during two forward ranges. A hydraulic control is provided to enforce operation of the clutch in a manner consistent with a one-way shifting device.

Abstract: A diagnostic strategy for an automatic transmission having electronic shift control solenoids for controlling application and release of clutches and brakes during the establishment and disestablishment of torque ratios in multiple-ratio gearing for the transmission wherein provision is made for developing diagnostic data that detects failure modes due to a faulty shift solenoid by using predetermined failure modes stored in the RAM portion of a microprocessor and comparing those known failure modes to the actual performance of the shift solenoids.

Abstract: A pneumatic transmission for a motor vehicle is provided with a gear shifting device which comprises a first pneumatic cylinder mounted to a housing for moving a shift arm fixed to a shift shaft thereof in predetermined shift positions, and a second pneumatic cylinder mounted to the housing and arranged in a cross relationship with the first cylinder for moving the shift arm in predetermined select positions. The second cylinder includes a selector shaft and a select rod slidably disposed therein in an axially spaced opposite relationship with each other, and select arms extending from ends of the selector shaft and the select rod to converge toward an end portion of the shift arm. A yoke is provided to interlink the select arms with the shift arm so as to move the shift arm in the predetermined select positions through the clockwise and counterclockwise rotation of the shift arm by a linear movement of the selector shaft.

Abstract: A frictional engagement device for an automatic transmission, by which an input shaft and an output shaft are engaged or disengaged by use of oil pressure. A casing connected to an input shaft and a first piston disposed in the casing define a first oil pressure chamber. The first piston is rotationally movable by predetermined angle and is axially movable by predetermined distance relative to the casing. A second piston disposed in the first piston defines a second oil pressure chamber with the first piston, and the second piston is axially movable relative to the first piston. Separator plates axially slidably connected to the first piston and clutch discs axially slidably connected to a hub which is fixedly connected to the output shaft are engaged by a displacement of the second piston by supplying pressurized oil to the second oil pressure chamber and/or to the first oil pressure chamber.

Abstract: An engagement control valve for a fluid operated torque transmitter, such as a clutch, has a pulse width modulated (PWM) solenoid, a valve spool and an accumulator. The PWM solenoid supplies control pressure through a flow restrictor to a control chamber adjacent one end of the valve spool which responds by establishing a proportionate engagement pressure for the torque transmitter. The accumulator has a piston slidably disposed in the valve spool, adjacent the control chamber, for fluid communication with the control pressure from the PWM solenoid. A damping chamber is formed adjacent the other end of the valve spool and is in fluid communication with an exhaust port via a flow restrictor.

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.