Abstract: Hydraulic control system and method for an automatic transmission. The hydraulic control system includes a hydraulic pressure source, a flow rate control valve having a spool with an orifice and a drain hole, stroke position determining means, and pressure regulator means. The stroke position determining means determines that the spool is displaced from a large spool-stroke position where a communication area of the drain hole is not less than a first predetermined area, to a small spool-stroke position where the communication area is not more than a second predetermined area. The pressure regulator means regulates a hydraulic oil pressure downstream of the orifice and corrects the hydraulic oil pressure downstream of the orifice by adding a predetermined correction amount for a first predetermined time when the stroke position determining means determines that the spool is displaced from the large stroke position to the small stroke position.

Abstract: In a system for controlling an automatic transmission, at the time of ultra-low temperature start with the oil temperature of ?20° C. or less, control is carried out such that when the state that the actual line pressure is equal to or greater than an ultra-low set value continues for a period longer than a line-pressure low-pressure control command set time, it is determined that the line pressure is under regulation, maximizing an indicated value of the line pressure.

Abstract: The invention involves an agricultural machine with a drive train to be coupled onto the power take-off shaft of a tractor, with a transmission integrated into the drive train. In these types of agricultural machines it is frequently necessary, after starting at a high torque, to select a lower transmission ratio, so that the agricultural machine can be driven at an optimal speed by an engine to which sufficient power is then still available for the propulsion for the tractor. In order to make this possible, it is proposed, in an agricultural machine of this type, to construct the transmission as a continuously variable conical-disk belt or chain transmission which is preferably fully hydraulic, is coupled with a hydraulic clutch, and has idle-shifting in the starting transmission ratio.

Abstract: Hydraulic control apparatus includes a belt-drive CVT, a pressure regulator valve (P.REG.V) regulating the oil pressure produced by an oil pressure source, a controller programmed to develop a transmission control signal, a transmission actuator driven based on the signal, and a transmission control valve actuated by the actuator. There are provided a first oil passage for supplying an oil pressure regulated by the P.REG.V, a second oil passage for supplying the oil pressure regulated to a primary pulley cylinder chamber of the CVT and draining the oil pressure therefrom, a third oil passage for draining the oil pressure within the cylinder chamber, and a fourth oil passage downstream of the P.REG.V. The third and fourth oil passages are connected to supply an oil pressure to the cylinder chamber and establish a minimum oil pressure required for clamping the belt depending on reduction of the oil pressure within the cylinder chamber.

Abstract: There is provided a line pressure control apparatus that is comprised of a line pressure control section that controls line pressure according to its target value calculated based on input torque information, target gear ratio, and so forth; and a line pressure setting section that sets the upper limit of the line pressure according to an inputted range signal when the engine speed is equal to or higher than a predetermined speed. The line pressure control section suppresses an increase in line pressure by controlling the line pressure such that it does not exceed the set upper limit in the case where the upper limit of the line pressure has been set. Therefore, it is possible to prevent the occurrence of cavitation noise in an oil pump, which generates basic pressure for line pressure, during high-speed engine revolution.

Abstract: A power transmission device for utility machinery is disclosed, the device including: a) a sleeve supporting a first sheave member having a first face; b) a hub received through said sleeve and moveable axially in relation thereto, said hub supporting a second sheave member having a second face that opposes said first face such that said first and second faces define therebetween a groove adapted to receive a belt and relative axial movement between said sleeve and said hub being adapted to vary at least one of pitch diameter and grip imparted to said belt from said sheaves; and c) an actuator mechanism adapted, through control of relative axial displacement between said sleeve and said hub, to vary at least one of said pitch and grip, said actuator mechanism comprising a control rod disposed substantially perpendicularly to the line of action of said axial displacement and connected to said hub through a link mechanism, said control rod being adapted to rotate and said link mechanism being adapted to transl

Abstract: A transmission with a drive side and an output side conical disk pair. One conical disk pair includes a fixed disk carried by a shaft, a movable disk non-rotatably connected with and axially movable relative to the shaft, and a support ring axially attached to the shaft adjacent a back side of the movable disk. A pressure chamber between the support ring and the back side of the movable disk is supplied with hydraulic pressure medium through a passage in the shaft that opens to the surface of the shaft. An end region of the movable disk when moved along the shaft passes over the opening at a maximum spacing of the movable disk from the fixed disk, and a hydraulic medium connection exists between the passage and the pressure chamber through drainage slots between an inner surface of the movable disk and the peripheral surface of the shaft.

Abstract: Hydraulic control system and method for a belt-drive continuously variable transmission (CVT). The system includes an oil pump operative to produce an oil pressure and an oil flow amount which are supplied to the CVT, a pressure regulator valve operative to regulate the oil pressure, an oil supply passage for supplying oil to the belt on a downstream side of the pressure regulator valve, means for detecting an engine operating condition and generating a signal indicative of the engine operating condition detected, and a controller programmed to calculate a CVT input torque based on the signal, calculate a required belt lubricating oil flow amount to be supplied to the belt on the basis of the signal and the CVT input torque, determine a minimum speed of the oil pump based on the required belt lubricating oil flow amount, and control the oil pump at the minimum speed.

Abstract: A hydraulic system of a CVT transmission of a motor vehicle is proposed, which has an oil pump for conveying oil from an oil sump to a variator comprising a first pulley set and a second pulley set. In each case, a valve mechanism is provided for controlling a pressure acting on the pulley set concerned. Between the valve mechanisms associated with the respective pulley sets is arranged a pressure selector valve, whose position determines which of the the valve mechanisms controls a main pressure to be delivered by the oil pump.

Abstract: CVT control unit of a belt CVT checks whether a reverse rotation of pulleys is generated. When the reverse rotation is generated, a PLpri torque capacity is calculated from a primary pressure Ppri, and this PLpri torque capacity is used as a torque limit value of a torque-down control of an engine control unit. An input torque to a transmission mechanism is compared with the PLpri torque capacity, and when the input torque exceeds the PLpri torque capacity, shortage of the PLpri torque capacity for the input torque is calculated. Then, this shortage is added to the input torque as a correction amount, and a line pressure is set on the basis of a result of this addition.

Abstract: A device, in a continuously variable belt transmission system, for guiding a conical pulley (3) of a variator on a variator shaft (1). The moveable conical pulley (3) is fitted onto two bearing sections (4, 5) of the variation shaft (1). At least one cylindrical pin (6), which is fitted into an axial guide grove (7) in the variator shaft (1) and an axial guide groove (8) of the movable conical pulley (3), is provided to transfer torque between the movable conical pulley (3) and the variator shaft (1).

Abstract: There is provided an oil pressure reduction rate restricting apparatus for a V-belt type continuously variable transmission, which is comprised of a reduction rate restricting section that calculates a reduction rate restricted secondary pressure and a reduction rate restricted primary pressure by restricting respective reduction rates of the target secondary pressure and the target primary pressure when the reduction rates of the target secondary pressure and the target primary pressure calculated by a target secondary pressure calculating section and a target primary pressure calculating section, respectively, are equal to or greater than respective predetermined values. The secondary pressure and the primary pressure are controlled based on the reduction rate restricted secondary pressure and the reduction rate restricted primary pressure whose reduction rates have been restricted such that the gradient thereof are small.

Abstract: A transmission includes a set of pulleys, in which at least one disc is axially displaceable and provided with cylinder piston elements. The cylinder/piston elements include at least one pressure chamber with radial walls and concentric cylinder walls and at least one of the radial walls of the pressure chamber is secured to one of the concentric cylinder walls by an immovable fit. The wall near to the fit is produced with a resiliently hingeable feature, in which the hinging feature is realized with the inclusion of an axially extending sleeve like foot part, integral to the wall, and with both axial faces thereof extending uninterrupted smoothly up to the lower end part of the wall.

Abstract: A continuously variable transmission for a motor vehicle, possessing a variator (2, 2?) with a primary V-pulley set (3, 3?) and a secondary V-pulley set (4, 4?). In this arrangement are a primary V-pulley disk (5, 5?) and a secondary V-pulley disk (6, 6?), which are axially slidable by hydraulic force for the controlled adjustment of a pressure can be, respectively, loaded with an oil flow through an electro-hydraulically controlled pressure supply apparatus (1, 1?). The pressure supply apparatus (1,1?) is so designed, that the oil flow is brought to the V-pulley disks (5, 5?, 5, 6?) through a pressure line (8, 8?, 9, 9?) with at least one pressure controller (10, 10?, 11, 11?) and one pressure chamber (12, 12?, 13, 13?) with a variable volume (V1, V2).

Abstract: A pressure feed in a shaft (1) of a transmission with a hydraulic or pneumatic control device through which the pressure feed can be acted upon with the pressure medium, with a gearbox (2), in which the shaft (1) is positioned through at least one bearing (3), whereby the gearbox (2) has a beating bore (4) in the region of the bearing (3) and whereby the bearing (3) is affixed axially in the gearbox (2) using a retaining sheet (5), with a gearbox cover (6) which covers the bearing bore (4) of the gearbox (2) and has feeding bores (7, 8) through which the pressure medium is transmitted from the hydraulic or pneumatic control device to the shaft (1). A pressure line (10) consisting of a tube (11) and a connection piece (12) inseparably connected pressure-tight to the tube be arranged between the hydraulic control device and a feeding bore (8) of the gearbox cover (6) arranged parallel to the shaft (1).

Abstract: A hydraulic fluid feed mechanism that feeds into a shaft (1) of a transmission having a hydraulic control device, by which the hydraulic feed mechanism can be supplied with hydraulic fluid, comprising a transmission housing (3) in which the shaft is held, and a housing cover (7) that is equipped with feed bores (8, 9), by which the hydraulic fluid is fed from the hydraulic control device into the shaft (1). A hydraulic fluid line (12) is positioned between the hydraulic or pneumatic control device and a feed bore (9) in the housing cover (7) that extends parallel to the shaft (1), with this hydraulic fluid line being comprised of a fitting (13) and a tube (14) which is permanently inserted into the fitting at nearly right angles, forming a pressure-tight seal.

Abstract: A system (10), in particular an electrohydraulic system (10), for adjusting the contract pressures of a continuously variable gear, in particular a double-cone pulley belt-contact gear, which has a device for changing the gear ratio of the gear having at least one primary pressure chamber and one secondary pressure chamber is proposed. An electrically triggerable primary pressure valve (Vprim) for adjusting the pressure in the primary pressure chamber and an electrically triggerable secondary pressure valve (Vsec) for adjusting the pressure in the secondary pressure chamber are provided. The pressure (pprim) of the primary pressure chamber and the pressure (psec) of the secondary pressure chamber can be carried to the secondary pressure valve (Vsec). The object is to enable a more-accurate adjustment of the pressure (pprim) in the primary pressure chamber.

Abstract: A variator for ratio adjustment of a continuously variable chain drive transmission having one variator shaft (1) and one variator pulley (2) supported upon the variator shaft (1) and axially movable by pressurizing a variator pressure chamber (31). The variator shaft (1) has on one end an axial hole (10) through which the variator pressure chamber (31) and a second pressure chamber (8) can be loaded with pressure independent of each other. The pressure is supplied to the variator pressure chamber (31) via a first section (13) of the axial hole (10) and the pressure is supplied to the second pressure chamber (8) via a non-rotating pipe (7) and a second section (15) of the axial hole (10), the pipe (7) is situated within the first hole section (13).

Abstract: A hydraulic controller of an automatic transmission which releases the lockup clutch when it fails. An output port of a solenoid valve is connected to a port of a lockup control valve and a port of a garage shift valve. An output port of a solenoid valve is connected to a port of the lockup control valve and a port of the garage shift valve. At least one of the solenoid valves is freely duty-controlled. A pattern, which enables regular control of the automatic transmission in normal operation and does not allow the lockup clutch to change from its released state to its engaged state, is selected for use from among plural combinations of signal pressures of the solenoid valves.

Abstract: The invention relates to a device for controlling the contact pressure of a transmission element of a continuously variable transmission, especially the traction element of a flexible drive for motor vehicles. The inventive device is provided with at least two levers as the transmission elements that provide the contact pressure depending on torque and ratio. Said levers are pivoted to the driving transmission elements and to the driven transmission elements and act upon an axially displaceable transmission element that indirectly or directly exerts the contact pressure via at least one rolling element each. The lever length effective to exert the contact pressure can be varied in accordance with the selected transmission ratio.

Abstract: A continuously variable transmission having a primary pulley and a secondary pulley on which a belt wound on the primary pulley is fitted. The width of the groove on the primary pulley is adjusted by the oil pressure in the primary hydraulic chamber in the primary cylinder, the width of the groove on the secondary pulley is adjusted by the oil pressure in the secondary hydraulic chamber in the secondary cylinder. The switching operation between the speed change operation in a state in which the line pressure is supplied to the secondary hydraulic chamber and the primary pressure is supplied to the primary hydraulic chamber by the oil passage switching valve, and the speed change control in a state in which the line pressure is supplied to the primary hydraulic chamber and the primary pressure is supplied to the secondary hydraulic chamber can be performed.

Abstract: A belt clamping pressure setting device includes: a belt clamping pressure setting unit that sets a belt clamping pressure of a continuously variable transmission that includes an input-side pulley, an output-side pulley, and a belt running between the input-side pulley and the out-side pulley; an input revolution detection sensor that detects a number of input revolutions of the input-side pulley; an output revolution detection sensor that detects a number of output revolutions of the output-side pulley; an input torque detection unit that detects an input torque to the input-side pulley; a reference clamping pressure computing unit that computes a reference clamping pressure, based on the number of input revolutions detected by the input revolution detection sensor, the number of output revolutions detected by the output revolution detection sensor, and the input torque detected by the input torque detection unit; and a belt clamping pressure computing unit that computes the belt clamping pressure to be set

Abstract: A control system for a continuously variable transmission and continuously variable transmission wherein such is utilised, includes a drive belt located between pulley discs of a first pulley and of a second pulley, the pulleys being rotatable at a rotational speed and being operable by a first and a second piston/cylinder assembly respectively. The control system controls the respective cylinder pressure in the first and second piston/cylinder assemblies, at least based on a torque signal representing the torque to be transmitted by the transmission and two speed signals representing the rotational speeds of the first and second pulley, for clamping the drive belt between the discs thereby enabling torque transmission between the pulleys and the drive belt.

Abstract: The invention relates to a control circuit for generating a control signal (I) for controlling the transmission ratio adjustment of a belt transmission continuously adjustable with respect to its transmission ratio. The belt transmission includes a drive end (7), an output end (8) and a primary valve (15) for adjusting the transmission ratio. The primary valve (15) is driven by the control signal (I). The control circuit includes means for generating the control signal (I) in dependence upon operating parameters of the vehicle transmitted to the control circuit. It is suggested that the control signal (I) is generated in dependence upon a value (y) for a desired speed of the transmission ratio change or from a quantity derived therefrom. The value (y) for the desired speed of the transmission ratio change is determined from the operating parameters transmitted to the control circuit.

Abstract: A gear change control system of a belt-type continuously variable transmission includes: a movable pulley piston chamber for causing a thrust force to a movable pulley varying a groove width of primary pulley and secondary pulley. The movable pulley piston chamber has double-piston constitution including: a primary clamp chamber and a secondary clamp chamber, for causing a clamp force of clamping the belt, and a cylinder chamber including a primary pulley cylinder chamber and a secondary pulley cylinder chamber, for causing a differential thrust force at a gear change. A clamp chamber oil pressure setting section sets up a clamp chamber oil pressure by the following calculation: dividing the one of the primary thrust force and the secondary thrust force by addition of: applied pressure area of one of the primary clamp chamber and the secondary clamp chamber, and applied pressure area of the cylinder chamber on a selected side.

Abstract: A hydraulic transmission (21) has an electric actuator (86) for changing its output/input rotation speed ratio. A controller (19) of the actuator memorizes a command current value to the actuator supposing that load is not applied on the hydraulic transmission, and calculates a value of load applied on the hydraulic transmission by calculating a difference between an actual command current value to the actuator and the memorized command current value. A command current value is compensated based on the value of load, and the actuator receives feedback to be controlled. A vehicle may have a differential mechanism (10), which combines rotation powers on input side and output side of the hydraulic transmission. A detector (82) detects rotation speed of a main speed change output shaft (27) serving as an output shaft of the differential mechanism.

Abstract: A controller (50) controls the supply of oil pressure to a primary pulley (41) and a secondary pulley (42) of a belt-drive continuously variable transmission (1) in accordance with the depression amount of an accelerator pedal (81) of a vehicle. When slippage is detected in a V-belt (43) that is wrapped around the primary pulley (41) and secondary pulley (42), the controller (50) reduces the output torque of an engine (70) of the vehicle to stop the V-belt (43) from slipping. Meanwhile, damage to the V-belt (43) caused by slippage is prevented by reducing the oil pressure supply to the secondary pulley (42).

Abstract: A continuously variable transmission having a primary pulley and a secondary pulley on which a belt wound on the primary pulley is fitted. The width of the groove on the primary pulley is adjusted by the oil pressure in the primary hydraulic chamber in the primary cylinder, the width of the groove on the secondary pulley is adjusted by the oil pressure in the secondary hydraulic chamber in the secondary cylinder. The switching operation between the speed change operation in a state in which the line pressure is supplied to the secondary hydraulic chamber and the primary pressure is supplied to the primary hydraulic chamber by the oil passage switching valve, and the speed change control in a state in which the line pressure is supplied to the primary hydraulic chamber and the primary pressure is supplied to the secondary hydraulic chamber can be performed.

Abstract: A belt-type continuously variable transmission having a forward clutch is incorporated with a speed-changing hydraulic pressure control system. The control system includes an engaging pressure regulating device for outputting an engaging pressure for the forward clutch. An electronically controlled hydraulic pressure control valve is provided to output a signal pressure which is able to cause the engaging pressure regulating device to set the engaging pressure. A control unit is provided to output a control command signal to the hydraulic pressure control valve, the control command signal causing the hydraulic pressure control valve to output the signal pressure. Here, the engaging pressure regulating device is arranged to output a minimum value of the engaging pressure in response to a maximum value of the signal pressure from the hydraulic pressure control valve, and to output a maximum value of the engaging pressure in response to a minimum value of the signal pressure.

Abstract: When a speed of a vehicle is less than 8 km/h, an upshift determination condition is established, an idle switch signal is turned off, and a downshift is detected, an operating speed of the step motor is limited. Thereby, since the operating speed of the step motor is limited even when the vehicle is rapidly decelerated and re-accelerated before a pulley ratio is returned to a lowest value Lo, a shift speed of the downshift performed in the re-acceleration is lowered, and no slippage occurs in a V-belt between pulleys.

Abstract: In case information such as an actual gear ratio is not stored in an EEPROM 28 due to a trouble of a backup power source 29 or like when an initialization operation of a step motor 27 is performed at the time of start of a vehicle or during stoppage of the vehicle, an output torque of an engine is limited before the initialization operation. Thereby, even if an accelerator is depressed during the initialization operation of the step motor 27 in which a sufficient primary pulley pressure cannot be ensured, the output torque of the engine is limited, so that torque inputted to a V-belt type continuously variable transmission is small and slippage does not occurs between the primary pulley and a secondary pulley.

Abstract: There is provided an oil pressure reduction rate restricting apparatus for a V-belt type continuously variable transmission, which is comprised of a reduction rate restricting section that calculates a reduction rate restricted secondary pressure and a reduction rate restricted primary pressure by restricting respective reduction rates of the target secondary pressure and the target primary pressure when the reduction rates of the target secondary pressure and the target primary pressure calculated by a target secondary pressure calculating section and a target primary pressure calculating section, respectively, are equal to or greater than respective predetermined values. The secondary pressure and the primary pressure are controlled based on the reduction rate restricted secondary pressure and the reduction rate restricted primary pressure whose reduction rates have been restricted such that the gradient thereof are small.

Abstract: During a downshift of a belt-drive continuously variable transmission, occurring owing to vehicle deceleration, a CVT controller foretells that a slippage between a drive belt and each of primary and secondary variable-width pulleys tends to occur, when a primary pulley pressure is less than a first predetermined pressure level and a primary pulley speed is less than a first predetermined rotational speed. When the belt slippage has been foretold, the CVT controller inhibits the primary pulley pressure from dropping by setting an actual transmission ratio calculated before a set time period from a time when the slippage has been foretold or a transmission ratio of a relatively higher speed side as compared with a ratio-change operating state obtained when the slippage has been foretold, to a desired transmission ratio, or by relatively rising a line pressure as compared with a line pressure level produced when the slippage has been foretold.

Abstract: A shift control system for a V-belt type CVT is constructed to input a target torque signal obtained by estimating engine torque in accordance with vehicle operating conditions and a target shift ratio of the CVT, input an actual torque signal obtained by detecting actual engine torque, synthesize the target and actual torque signals to provide an estimated-torque signal, and control the line pressure in accordance with the estimated-torque signal.

Abstract: There is provided a hydraulic control apparatus for a belt CVT, which is comprised of a pulley pressure control section that controls the line pressure in accordance with the oil amount balance of an oil pump based on the engine speed and the oil temperature during a select-judgment period from the detection of a change from a driving range to a non-driving range or a change from the non-driving range to the driving range to the lapse of a predetermined period of time, or when the non-driving range is detected. This eliminates the possibility that the oil pump cannot generate a specified oil pressure due to a decrease in the engine speed. Further, the secondary pressure is multiplied by the ratio of the line pressure in accordance with the oil amount balance of the oil pump to the line pressure which has been intended to be specified, and the secondary pressure is controlled according to the calculation result. This makes it possible to maintain the pulley ratio without causing a down-shift of the belt CVT.

Abstract: CVT control unit of a belt CVT checks whether a reverse rotation of pulleys is generated. When the reverse rotation is generated, a PLpri torque capacity is calculated from a primary pressure Ppri, and this PLpri torque capacity is used as a torque limit value of a torque-down control of an engine control unit. An input torque to a transmission mechanism is compared with the PLpri torque capacity, and when the input torque exceeds the PLpri torque capacity, shortage of the PLpri torque capacity for the input torque is calculated. Then, this shortage is added to the input torque as a correction amount, and a line pressure is set on the basis of a result of this addition.

Abstract: A hydraulic control system for a continuously variable transmission (CVT) includes a ratio control valve for distributing fluid to components in the CVT. The ratio control valve receives a system controlled pressure and distributes both a high pressure control fluid and a low pressure control fluid. A variable bypass valve distributes excess fluid pressure back to the inlet of a control pump. The bypass valve is responsive to the pressure differential between the high pressure control fluid and the system pressure controlled fluid to establish the operating point at which the excess fluid is bypassed. The system pressure controlled fluid is the highest pressure in the system. During operation of the CVT, the high pressure control fluid operates on one variable sheave of the CVT and the low pressure control fluid operates on another variable sheave of the CVT.

Abstract: A continuously variable transmission, having a first pair of conical disks including an axially moveable disk and an axially non-movable disk whereby a running radius of the first pair of disks is changeable, a second pair of conical disks including an axially movable disk and an axially non-movable disk whereby a running radius of the second pair of disks is changeable, and an endless transmission element arranged to couple the first pair of disks with the second pair of disks. A first hydraulic actuator in operative connection with the movable disk of the first pair of disks for axially moving the disk, the first actuator having an inlet port, and a second hydraulic actuator is in operative connection with the movable disk of the second pair of disks for axially moving the disk, the second actuator having an inlet port. A first, four-quadrant controllable pump-motor has a first port connected to the inlet port of the first actuator, and a second port connected to the inlet port of the second actuator.

Abstract: In case a primary hydraulic pressure sensor is normal, when reverse rotation of pulleys is detected a primary pulley (Plpri) torque capacity is calculated from a primary pressure detected by the primary hydraulic pressure sensor. When the primary hydraulic pressure sensor fails, a secondary hydraulic pressure sensor is checked, and when the secondary hydraulic pressure sensor is normal, the PLpri torque capacity is determined from a secondary pressure detected by the secondary hydraulic pressure sensor by using a map. On the other hand, when the secondary hydraulic pressure sensor fails too, the PLpri torque capacity is read out from the map by using a secondary pressure target value as the secondary pressure.

Abstract: There is provided a line pressure control apparatus that is comprised of a line pressure control section that controls line pressure according to its target value calculated based on input torque information, target gear ratio, and so forth; and a line pressure setting section that sets the upper limit of the line pressure according to an inputted range signal when the engine speed is equal to or higher than a predetermined speed. The line pressure control section suppresses an increase in line pressure by controlling the line pressure such that it does not exceed the set upper limit in the case where the upper limit of the line pressure has been set. Therefore, it is possible to prevent the occurrence of cavitation noise in an oil pump, which generates basic pressure for line pressure, during high-speed engine revolution.

Abstract: A transmission mechanism of continuously variable transmission in a vehicle comprises a primary pulley and a secondary pulley provided with a first cylinder chamber and a second cylinder chamber, with groove widths being changed by supply of hydraulic pressure, and a belt provided between the pulleys. A hydraulic pressure to the first cylinder chamber is controlled by CVT control unit through a shift control valve according to a driving state of the vehicle, and the second cylinder chamber is continuously supplied with a line pressure. CVT control unit includes an internal memory to retain a heavy-current system fail flag according to the failure information inputted from a motor control unit.

Abstract: In a system for controlling an automatic transmission, at the time of ultra-low temperature start with the oil temperature of −20° C. or less, control is carried out such that when the state that the actual line pressure is equal to or greater than an ultra-low set value continues for a period longer than a line-pressure low-pressure control command set time, it is determined that the line pressure is under regulation, maximizing an indicated value of the line pressure.

Abstract: Hydraulic control system and method for a belt-drive continuously variable transmission (CVT). The system includes an oil pump operative to produce an oil pressure and an oil flow amount which are supplied to the CVT, a pressure regulator valve operative to regulate the oil pressure, an oil supply passage for supplying oil to the belt on a downstream side of the pressure regulator valve, means for detecting an engine operating condition and generating a signal indicative of the engine operating condition detected, and a controller programmed to calculate a CVT input torque based on the signal, calculate a required belt lubricating oil flow amount to be supplied to the belt on the basis of the signal and the CVT input torque, determine a minimum speed of the oil pump based on the required belt lubricating oil flow amount, and control the oil pump at the minimum speed.

Abstract: Hydraulic control apparatus includes a belt-drive CVT, a pressure regulator valve (P.REG.V) regulating the oil pressure produced by an oil pressure source, a controller programmed to develop a transmission control signal, a transmission actuator driven based on the signal, and a transmission control valve actuated by the actuator. There are provided a first oil passage for supplying an oil pressure regulated by the P.REG.V, a second oil passage for supplying the oil pressure regulated to a primary pulley cylinder chamber of the CVT and draining the oil pressure therefrom, a third oil passage for draining the oil pressure within the cylinder chamber, and a fourth oil passage downstream of the P.REG.V. The third and fourth oil passages are connected to supply an oil pressure to the cylinder chamber and establish a minimum oil pressure required for clamping the belt depending on reduction of the oil pressure within the cylinder chamber.

Abstract: A belt-type CVT is comprised of a driving pulley and a driven pulley each of which has having a transmission piston chamber and a clamp piston chamber. An effective cross sectional area of the driving-side clamp piston chamber is equal to an effective cross sectional area of the driven-side clamp piston chamber. The driving-side clamp piston chamber is fluidly communicated with the driven-side clamp piston chamber through a common passage.

Abstract: A belt-type continuously variable transmission has a drive pulley (16) and a driven pulley (26) in which the pulley width between a fixed disk and a movable disk may be varied in accordance with oil pressure, a V-belt (5) which is wound around the drive pulley and driven pulley, and a clutch for controlling the transmission of torque from an engine to the drive pulley. The belt-type continuously variable transmission further has a first spring (40) for constantly urging the movable disk of the drive pulley to the fixed disk side and a second spring (41) for constantly urging the movable disk of the driven pulley to the fixed disk side.

Abstract: The invention relates to a safety device (SD) to be used in connection with machines and devices in the production or finishing line of paper and/or paperboard as well as in connection with devices utilized for production of pulp used in the manufacture of paper and/or paperboard. According to the invention the safety device (SD) comprises a reeling core (RC) and a safety structure (SW) reeled around said reeling core (RC). In a preferred embodiment of the invention the reelable safety device (SD) is composed of separate, substantially rigid lamellae (L) that are attached to each other in an articulated manner. As a result of the reelable structure, the safety device (SD) can be easily reeled away from the working area during maintenance and repair and thereafter it can be easily and rapidly reeled back into its place.

Abstract: A system for determining the speed of a pump (6) used to supply hydraulic fluid for a control system is disclosed. The pump output exhibits small pressure fluctuations and these are detected by a transducer (50) and provided to a data processor (54) which analyses the output of the transducer and calculates the speed of the pump.

Abstract: The invention describes a method and a device for controlling a drive train of a motor vehicle with a drive assembly and a continuously variable automatic transmission with a variable speed gear, wherein an electronic control unit for controlling at least the continuously variable automatic transmission and an emergency device are provided, with this unit being activated in the event of failure of the electronic control unit and a constant pressure/force ratio being established in the variable speed gear. Pursuant to the invention, in the event of failure of the electronic control unit the frictional connection between the drive assembly and the continuously variable automatic transmission is interrupted before the emergency driving mode is made available through the emergency device by re-establishing the frictional connection.

Abstract: A hydraulic controller (10, 10a, 10b) for a continuously variable transmission (12) is proposed. Using a pump (42), the delivery chambers (24, 26) of a first and second adjusting device (14, 16) are acted upon to alter the transmission ratio of the transmission (12). The valve (36, 36a, 36b), which can be controlled using a pressure drop created at a throttle position (50), serves to control the pressure in the delivery chamber (24). According to the invention, additional means are provided to prevent an adjustment of the transmission (12) in the “low” direction in the (N) operating state and, as necessary, in the (P) and (N) operating states.