Abstract: A continuously variable transmission and method for preventing transmission belt slippage in the case of a sudden change in load torque on the transmission involve one or both of inserting a lag in the transmission with a torsional spring damper or elastomer damper device between the device to be driven and an output shaft of the secondary pulley of the transmission, and inserting a lag in a hydraulic pressure control loop of the transmission compensating for a difference between the rate of torque transmission between the device to be driven and the transmission, and a response rate of the hydraulic pressure control loop to a sudden change in load torque. The transmission is used to drive an aircraft electrical generator at a constant speed in the disclosed embodiment.

Abstract: A continuously variable transmission (CVT) has a drive sheave and a driven sheave, each of which has an adjustable portion, that are positioned by hydraulic control pistons. The pistons are pressurized from a control system to properly position each adjustable portion, such that a flexible drive member, trained over the sheaves, operates at the required diameter to establish the desired speed ratio between the drive sheave and the driven sheave. The control has two variable displacement pump assemblies that supply hydraulic fluid at the required pressure to maintain the desired ratio and to effect a ratio change as required by the operating conditions. One of the pumps supplies a primary pressure which is proportional to the torque requirement of the CVT and the other pump supplies the necessary pressure bias to effect the ratio change.

Abstract: A continuously variable transmission is provided with an adjustable pulley assembly including two sheaves on a pulley shaft, at least one sheave is axially movable with respect to the pulley shaft by a hydraulically operated movement, the movement includes a piston/cylinder assembly for generating a first force acting on the movable sheave and centrifugal pressure compensator for generating a second force acting on the movable sheave in a direction opposite with respect to the first force; the centrifugal pressure compensator includes a further cylinder fixed to the axially movable sheave in radial direction beyond the piston/cylinder assembly, and a further piston fixed to the pulley shaft, the further piston and the further cylinder form a further piston/cylinder assembly.

Abstract: A CVT-oil-pressure control apparatus has a primary cylinder provided for a primary pulley, having an oil chamber for applying an oil pressure to the primary pulley and a balance oil chamber for applying a centrifugal oil pressure to the primary pulley in a direction which is reverse of a centrifugal oil pressure generated in the oil chamber; a primary valve for adjusting a primary pressure to be applied to the oil chamber based on a line pressure applied by an oil pump; and a balance oil line that connects a drain port of the primary valve and the balance oil chamber. The oil is supplied from the primary valve to the balance oil chamber through the balance oil line.

Abstract: A continuously variable transmission wherein each of two parallel shafts carries a pulley having a fixed flange and a second flange movable axially of the shaft toward and away from the respective fixed flange. An endless torque transmitting chain or belt is trained over the two pulleys. At least one flange of at least one of the pulleys is assembled of two or more parts which consist of sheet metal and are welded and/or otherwise affixed to each other.

Abstract: A continuously variable speed transmission with a first adjustable pulley on an input shaft, a second adjustable pulley on an output shaft, and an endless chain or belt trained over the pulleys employs at least one coil spring which biases one flange of one of the pulleys axially of the respective shaft. The coil spring has larger-diameter end convolutions and smaller-diameter intermediate convolutions. A plenum chamber of a torque sensor or of at least one of several piston-cylinder units—which serve to adjust the axially movable flanges of the pulleys—is bounded in part by a check valve in the form of a composite seal having a rigid annular element and an elastic annular element. One of the annular elements surrounds the other element.

Abstract: The method for monitoring a continuously variable transmission (CVT) with a variator for adjustment of the speed ratio, which has its primary and secondary adjustment devices respectively controlled by a pressure-regulating valve, consists of a travel monitoring and/or pressure monitoring of the pressure-regulating valves wherein in case of detection of an incorrect operation the power-flow transmitting clutch is opened.

Abstract: A control system controls a line pressure applied to a CVT upon taking account of a certrifugal pressure caused by a rotation of pulleys. The control system determines whether the centrifugal pressure is greater than a predeterminied value only by which the pulley transmits an input torque from an engine. When the determination is affirmative, a lower limit of a duty ratio for operating a line pressure control valve is switched from a lower limit of a linear range to 0% duty ratio. Therefore, an actual transmissiou ratio control range is expanded while preventing an undershoot of the line pressure.

Abstract: An electronic transmission control system for an automotive vehicle with a belt-type continuously variable automatic transmission comprises a transmission ratio control device including a first motor-driven oil pump supplying working pressure directly to a secondary pulley actuation chamber, and a second motor-driven oil pump supplying working pressure directly to a primary pulley actuation chamber and enabling working oil to come and go between the primary and secondary pulley actuation chambers therethrough. A first control section is provided for controlling the first motor-driven oil pump with feed-forward compensation for the working pressure supplied to the secondary pulley actuation chamber, based on changes in a flow rate of the working oil coming and going between the primary and secondary pulley actuation chambers, so that the secondary pulley pressure is regulated as a belt capacity holding pressure needed to hold a belt capacity of the drive belt in a first motor-driven pump side.

Abstract: In a pair of conical disks (pulley halves) of an infinitely variable cone-pulley transmission, in the case where the conical disks are spaced apart, a pressure compartment through channels formed in a shaft A connects to a pressure chamber that serves to move one of the conical disks. The pressure compartment is on one side delimited by a piston-like part serving to modulate the pressure inside the compartment dependent on the torque acting on the pair of conical disks. By switching on the connection to the pressure compartment, the system pressure can be modulated not only dependent on the torque but also dependent on the transmission ratio. Advantageous designs of the valve arrangement for switching the pressure compartment on and off are described.

Abstract: A continuously variable transmission and method for preventing transmission belt slippage in the case of a sudden increase in load torque on the transmission involves both inserting a lag in the transmission to allow the control loops time to respond to the sudden increase in load torque and speeding up the responses of the control loops in response to the sudden increase in load torque. The transmission is used to drive an aircraft electrical generator at a constant speed in the disclosed embodiment.

Abstract: A continuously variable transmission, and particularly a control arrangement thereof and a method for reducing belt slippage in the transmission, are disclosed. A single source of constant hydraulic pressure is operatively connected for driving each of the hydraulically operated actuators for axially movable sheaves of primary and secondary pulleys of the transmission. A hydraulic pressure control loop controls the hydraulic pressure applied to the actuator of the secondary pulley as a function of the sensed load of the device being driven on the transmission and the pitch radius of the secondary pulley. An output speed control loop controls the output speed of the transmission driving the device to be driven. Preferably, the output speed control loop may be set to control the output speed at a constant value for driving an aircraft electric generator. The control arrangement and method are simpler and more robust than previous control arrangements and methods.

Abstract: An infinitely variable transmission has a first pair of conical flanges arranged on a first shaft and a second pair of conical flanges arranged on a second shaft, where each pair has an axially movable flange and an axially fixed flange. A torque-transmitting means is disposed between the pairs of conical flanges. Piston/cylinder units and plenum chambers comprising circular ring-shaped elements serve to apply pressure to and effect axial movement of the movable conical flanges. The ring-shaped elements have radially inner portions with openings to receive the shafts. The radially inner portion of at least one of the ring-shaped elements has a welded seam connecting the ring-shaped element to the shaft received by its opening.

Abstract: In a transmission having shaft-mounted components operated by a pressurized medium or fluid, the fluid is supplied to the components using an at least partially hollow shaft. A hollow tube within the bore of the shaft carries the fluid. The tube may be divided into separate passageways so as to control flow of fluid to selected components and isolate components from each other. The fluid pressure in the components may be torque-dependently modulated by a torque sensor.

Abstract: A pulley structure of a belt driven continuously variable transmission includes a fixed sheave, a moving sheave, a cylinder member fixed to the moving sheave, a piston member fixed to a pulley shaft and a hydraulic actuator formed by the cylinder member and the piston member for actuating the cylinder member so as to move the moving sheave axially on the pulley shaft. The pulley structure further includes a mating section integrally formed with the cylinder member, a mating surface on the mating section and formed annularly around and perpendicularly to the pulley shaft, a flange surface provided on the moving sheave and formed annularly around and perpendicularly to the pulley shaft, a mating means for mating the mating surface with the flange surface so as to have a tight contact therebetween, a bolt hole bored on the mating section, a tapped hole provided on the moving sheave, and a fastening means for fastening the mating section to the moving sheave with bolts.

Abstract: A pressure reducing valve and a continuously variable transmission comprising an output pressure feedback loop operatively connected to provide proportional control of an output pressure of a flow of fluid passing through the pressure reducing valve in response to an input signal applied to a pilot stage control valve of the pressure reducing valve from an external source. The pressure reducing valve includes a main stage two-way spool valve having a valve body and a valve spool movable within the valve body in response to an imbalance of forces on the valve spool. The valve body has a supply port for receiving pressurized fluid from a source of constant hydraulic pressure and a load port for communicating a load pressure and flow from the spool valve to an actuator of the secondary pulley of the transmission to maintain transmission belt tension while preventing or minimizing belt slippage. The open area of the load port is dependent on the position of the valve spool within the valve body.

Abstract: An infinitely variable-speed transmission for use in the power train of a motor vehicle has two rotary sheaves and an endless flexible element trained over the sheaves to transmit torque from the flanges of one of the sheaves to the flanges of the other sheave when the one sheave is driven by the prime mover of the vehicle. The flanges have exposed conical surfaces which are frictionally engaged by the exposed end surfaces of pintles forming part of the flexible element when the latter transmits torque. The flanges are hardened, cushioned, roughened and/or otherwise treated at their exposed surfaces to promote the ability of the sheaves to eliminate or reduce noise on contact with the pintles, to stand long periods of use without extensive wear, and/or to transmit pronounced and variable torques.

Abstract: A control for a continuously variable unit (CVU) provides control pressures to the variable sheave portions of the CVU pulleys. A first of the pulleys has a direct control pressure and the second of the pulleys has a control pressure proportional to the direct control pressure. The proportional pressure is established by a pair of control valves. One of the control valves issues a bias pressure, proportional to the commanded ratio in the CVU, to the other of the control valves. The other control valve communicates a sheave control pressure, proportional to or equal to the bias pressure, to the second pulley to control the relative position of the variable sheave.

Abstract: A transmission is constituted by drive and driven side movable pulleys (11 and 16), a metallic V belt (15) and drive and driven side cylinder chambers (14 and 19) for controlling the width of both pulleys. A hydraulic control system for the transmission, according to the present invention, is characterized as follow. The line pressure (PL) is set using first and second regulator valves (31, 32). First control oil pressure (PC1) supplied to the drive side cylinder chamber is controlled using a first linear solenoid valve (41) and a first pulley control valve (43). Second control oil pressure (PC2) supplied to the driven side cylinder chamber is set using a second linear solenoid valve (45) and a second pulley control valve (47). In addition, first and second regulator valves (31, 32) regulates the line pressure using control back pressure which is the higher of first and second control back pressure respectively set by the first and second linear solenoid valves (41, 45).

Abstract: An emergency hydraulic control is provided for a transmission-dependent change of the hydraulic fluid pressures in a first and second hydraulic conical disk axial displacement of a continuously variable transmission, wherein a pump supplies at least the piston chamber of a second axial displacement, and a downstream-connected remote-controlled differential pressure regulator and at least one electro-magnetically actuable pressure relief valve limits the fluid pressure there, and feed from this supply the piston chamber of a first axial displacement, as well as a remote control having an opening function leading to the valve via the remote-control line, via a continuous way valve, whose opening movement into the flow-through position is controlled with the aid of the pressure present upstream of the valve, wherein at least the individual driving states such as forward running, reverse running and idling, can be selected by means of appropriate switching positions of an manual switching valve; and in case of an

Abstract: In a pulley arrangement of a belt-type continuously variable transmission, a ring member (6) integrated with a first cylinder member (3) is coupled to a second cylinder member (5) using splines (6d and 5c) to limit mutual movements of the first and second cylinder members and using snap ring (7) to limit the axial displacement therebetween in peripheral directions of the respective first and second cylinder members. The first cylinder member is slidably contacted on an outer peripheral surface of a hollow cylindrical portion of a second conical pulley component. The second cylinder member is fixed onto an outer peripheral surface of a shaft portion of a first conical pulley component.

Abstract: A continuously variable speed transmission has two adjustable sheaves and an endless chain or belt which is trained over and transmits torque between the sheaves. One of the sheaves can be driven by a prime mover, and the other sheave can drive a torque receiving device. Each sheave has a shaft, a first flange which is fixed to the shaft, and a second flange which is movable axially of the shaft toward and away from the first flange. The shaft portion between the flanges of at least one of the sheaves is located in the path of one or more sprays of a cooling and/or lubricating fluid which flows axially of the shaft and along the confronting conical surfaces of the flanges. The spray or sprays are supplied by the nozzle(s) of a conduit which receives fluid from a pump in the hydraulic system of the transmission.

Abstract: A continuously variable transmission for an automotive vehicle comprises a drive pulley including axially first and second wheel counterparts which define therebetween a pulley groove. The first wheel counterpart of the drive pulley is axially movable under an axial thrust to decrease the width of the pulley groove. A driven pulley is provided including first and second wheel counterparts which define therebetween a pulley groove. The first wheel counterpart of the driven pulley is axially movable under an axial thrust to decrease the width of the pulley groove. An annular belt is passed on the drive and driven pulleys to drivingly connect the drive and driven pulleys. The belt is fitted in the pulley groove of each pulley, and includes a plurality of elements which are aligned along periphery of the belt. A control unit variably controls the width of the pulley groove in accordance with a transmission ratio based on an operating condition of the vehicle, and sets the axial thrust (Q) so that a value of (Q.

Abstract: A system for adjusting the tension of a belt of a belt transmission provides a higher accuracy of the estimate of the engine torque, which is to be expected, and therefore a better proportioning of the tension is obtained. For this purpose, signals are made available from the engine control which controls the internal combustion engine. These signals make possible a precise estimation of the engine torque. In a first embodiment, this signal can, for example, be an estimated value for the engine torque to be expected. The estimated value is, for example, formed in the engine control. In a second embodiment, these signals can be the quantity of air mass inducted by the engine (that is, the signal derived therefrom) and the ignition angle of the engine. The tension of the belt can be reduced by the more accurate estimate of the engine torque so that an improved transmission efficiency results.

Abstract: A power train for use in motor vehicles has an infinitely variable transmission with two adjustable sheaves, an endless flexible torque transmitting element trained over the sheaves, and at least one hydraulic adjusting unit for each of the sheaves. The adjusting units receive pressurized fluid from a pump and the pressure of such fluid, and hence the extent of frictional clamping engagement between the sheaves and the flexible element, is regulated by a torque sensor including a plenum chamber with an outlet having an effective cross-sectional area which is variable in dependency upon variations of torque being applied to the torque sensor by the engine of the vehicle. The energy of fluid leaving the plenum chamber is used to operate a jet pump which draws fluid from a source for lubrication and/or cooling of the transmission and/or one or more clutches forming part of the power train.

Abstract: In a belt type continuously variable transmission, the oil for the canceler oil chamber and the oil for lubricating the endless belt are commonly used to reduce the required amount of oil to be supplied. The gear shift control oil is supplied to the pulley oil chamber of the driven pulley mounted on the output shaft of the belt type continuously variable transmission through a feed pipe, oil holes of a plug, an oil groove, oil holes of the output shaft and oil holes of the movable pulley half. The lubricating oil supplied to a first in-shaft oil chamber of the output shaft is further supplied through the oil holes of the output shaft to the canceler oil chamber of the driven pulley and also from the first in-shaft oil chamber through a throttle in the plug, the second in-shaft oil chamber and the oil holes of the output shaft to the endless belt.

Abstract: A continuously variable transmission control system determines the desired speed ratio for a continuously variable transmission from various input data received from the vehicle and operator. The desired speed ratio is compared with a commanded speed ratio to provide an error signal which establishes a new commanded speed ratio for the continuously variable transmission. The comparing process of desired speed ratio to commanded speed ratio is repeated until the error signal is substantially null. Also, the control provides an adaptive modifier for the actuator of the continuously variable transmission such that a comparison of actual transmission ratio to commanded speed ratio will determine if an adaptive modification is necessary. The control further provides a step control function which is operable when the ratio of the continuously variable transmission is moving toward an underdrive ratio.

Abstract: An apparatus for controlling a dynamic system, for example, a continuously variable transmission for an automotive vehicle which adjusts a gear ratio by bringing a pulley position of a primary pulley into agreement with a target one through a hydraulic system under the feedforward and sliding mode control is provided. The apparatus calculates a feedforward-controlled variable in addition to a feedback-controlled variable and adjusts the pulley position of the primary pulley to a target one using the hydraulic pressure provided based on the sum of the feedforward-controlled variable and the feedback-controlled variable, thereby enhancing the robustness of the sliding mode control without causing the hunting.

Abstract: A process for regulating continuously variable transmissions in motor vehicles by means of a controller includes a first control circuit as a speed controller for regulating the transmission input speed as the product calculated from the transmission output speed and the transmission ratio, and a second control circuit post-connected to the first control circuit as a speed gradient controller for regulating the time derivative of the transmission input speed. A correction value, dependent on the functional value of a correcting function and obtained from a correction element, is added to the summation element at the controller input of one of the two control circuits. The correction value is obtained such that the regulating ranges are specified, respectively, with a different control behavior of the controller.

Abstract: A hydraulic emergency control for changing the hydraulic oil pressure in the hydraulic conical pulley axial adjustment mechanism of a continuously variable transmission (10) for varying the clamping force ratio has a pump (20) in an open hydraulic circuit that supplies the respective piston chambers (17, 13) of the secondary and primary axial adjustment mechanisms with hydraulic oil. The primary and secondary oil pressures are regulated by separate oil pressure limiting valves (30, 40). At least one throttle valve (51) is arranged between the pump (20) and the output pipe (92) of the open hydraulic circuit, at a point where the pump volumetric flow can be influenced. The hydraulic emergency control allows a starting transmission ratio to be set in a low range when starting the vehicle, whereas a very small reduction ratio is selected at a high driving speed and at light throttle.

Abstract: For a CVT (3) a regulating system is proposed in which a corrector is located upstream of the control path. The disturbances and non-linearities in the control path (28) are taken into account in the corrector, via a mathematical model, so that the regulator can be designed as a simple PID regulator.

Abstract: An apparatus for manually engaging a primary clutch of a constantly variable transmission, which contains a fixed piston assembly enclosed within a movable cylinder assembly. The fixed piston assembly contains cylindrical center cup with a flange integrally connected to a first stepped cylindrical section, and a second stepped cylindrical section integrally connected to the first stepped cylindrical section. Several orifices extend through the first cylindrical section. A piston is connected to the second stepped cylindrical assembly. A movable cylinder is lcoated within the first stepped cylindrical section and is contiguous with the piston.

Abstract: The proposal is for a device for controlling a CVT (3) driven by a drive unit (1) in which an emergency running unit is activated on the breakdown of the electronic control device (15). It sets a constant compression or power ratio between the primary (S1) and secondary (S2) pulleys.

Abstract: A continuously variable transmission provided with a variator for adjusting the transmission ratio of the transmission and one or more hydraulic circuits for lubrication, cooling and transmission control, one or more pumps being installed for the hydraulic circuit. The transmission comprises at least one electric motor to give the transmission better sizing and an improved efficiency.

Abstract: A hydraulic emergency control for a gear-ratio-dependent change in hydraulic fluid pressures in a first and second hydraulic bevel-gear axial adjuster of a continuously variable transmission (10), is provided in which a pump (1) supplies at least the piston chamber (17) of the second axial adjuster, and at least one downstream pressure limiting valve (40) limits the fluid pressure there and moreover from this supply, via a continuous path valve (20), supplies the piston chamber (13) of the first axial adjuster, and the continuous path valve (20) is controlled with the aid of a pressure differential acting on a throttle valve (39) that is downstream of the pump (1) and is integrated with a switching valve (30).

Abstract: In a pulley working fluid (oil) passage arrangement for a belt-type continuously variable transmission having a V belt wound about a letter V-shaped groove formed with mutually opposing oblique surfaces of movable and stationary sheaves and a working fluid pressure cylinder chamber to which a working fluid pressure is supplied so as to move the movable sheave toward or away from the stationary sheave, thus a gear shift being varied, a first working fluid passage communicated with an axle chamber working fluid passage is extended in an axial direction of the axle member at an opposing surface thereof against the axle member and the movable sheave and a second working fluid passage having one end communicated with the first working fluid passage and the other end opened to a working fluid pressure cylinder chamber is extended along a radial direction of the axle member.

Abstract: Continuously variable transmission, in particular for a motor vehicle, provided with a primary pulley mounted on a primary shaft, a secondary pulley mounted on a secondary shaft, and a drive belt running over both pulleys, each pulley formed by two sheaves, one of which is movable axially relative to the other under the influence of a hydraulic cylinder, for setting the transmission ratio, a pumping unit with at least two pumps for delivering hydraulic medium to the hydraulic cylinders, and a control unit for controlling the pump delivery depending on the operating conditions of the transmission, includes a pumping unit with at least two pumps, the first of which serves as a booster pump for the second pump connected in series, and a switch valve, under the control of the control unit, fitted so that the two pumps can be switched over from series connection to parallel connection if the volume flow of the medium required by the transmission is greater than the available volume flow in the series connection.

Abstract: A hydraulic emergency control system for a continuous looped gear type continuously variable transmission (10) includes first and second hydraulic beveled conical pulley axial actuators controlling a gear ratio. A pump supplies a first piston chamber (13) of said first axial actuator via a sensor valve (20), wherein the sensor valve (20) is controlled by a flow control valve (73) connected downstream of the pump (80). The pump (80) supplies a second piston chamber (17) of the second axial actuator, with a pressure relief valve (40) limiting fluid pressure in said second piston chamber. Fluid in the second piston chamber (17) is controlled as a function of the fluid pressure in the first piston chamber (13) via a control line (52, 113).

Abstract: A metal V-belt type continuously variable transmission in which the length of a side of an element contacting with a V-face of a pulley is shortened to increase a ratio range. If the element side length of a metal element is represented by L, the angle of the V-face of the pulley is represented by .alpha., and the hertz surface pressure between the pulley and the metal element is represented by .sigma..sub.H, the following relation is established: L .varies. sin .alpha./.sigma..sub.H.sup.2. When the hertz surface pressure .sigma..sub.H is determined to be between an upper limit value defined by the wear durability of the metal element and a lower limit value defined by the limit tensile force of an endless belt, the element side length L can be decreased by decreasing the angle of the V-face of the pulley. Thus, the distance through which the metal element can be moved radially of the pulley is increased to increase the ratio range.

Abstract: Continuously variable transmission, for a motor vehicle, provided with a primary pulley with an input pulley shaft, a secondary pulley with an output pulley shaft, a drive belt positioned around the primary and secondary pulleys and a transmission mechanism which is constructed in combination with a direct/neutral/reverse group and is positioned after the secondary pulley and has at least two adjustable transmission ratios for forward drive. The primary pulley with input pulley shaft and the secondary pulley with output pulley shaft are each coupled via a gear group to, respectively, an input transmission shaft and an output transmission shaft. The two transmission shafts essentially lie in the extension of one another and the two pulleys are located on either side of the axis line of the two transmission shafts. A hydraulic control circuit is installed which has at least a primary and a secondary control valve for controlling the pressures for the primary and the secondary pulley respectively.

Abstract: A hydraulic control apparatus for a continuously variable transmission which can produce stable drive pulley pressure and driven pulley pressure and also control the speed change time. The line pressure regulated by the regulator valve 22 is supplied to the control valve 24.sub.DR of the drive pulley 5 and to the control valve 24.sub.DN of the driven pulley 7. These control valves regulate the line pressure according to the PB pressure and the PC pressure output from the solenoid valves SOL-B, SOL-C, respectively, and produce the drive pulley pressure P.sub.DR and the driven pulley pressure P.sub.DN. When the PB pressure and the PC pressure are both zero, and P.sub.DR =P.sub.DN, the control apparatus maintains the same gear ratio. When the PB pressure is increased from zero while keeping the PC pressure at zero, i.e. P.sub.DR >P.sub.DN, the gear ratio changes toward the high-speed overdrive. When the PC pressure is increased from zero while holding the PB pressure at zero, i.e. P.sub.DR <P.sub.

Abstract: The electro-hydraulic control device is designed to control a continuously variable loop transmission including a hydraulic bevel disk displacement device having two pairs of bevel disks, each pair of which has piston/cylinder elements with a piston chamber, and a pump for supplying one of the piston chambers with hydraulic oil. The electro-hydraulic control device supplies and regulates a hydraulic pressure in the piston chamber by means of a flow control valve (50) and a proportioning pressure relief valve (30). The electro-hydraulic control device also includes a pressure sensor (90) for generating an electronic pressure sensor signal according to the hydraulic pressure in a low-pressure control pressure line (34) connecting the flow control valve (50) and the proportioning pressure relief valve (30) and an electronic control unit for generating an electrical current for actuating the flow control valve (50) according to the pressure sensor signal.

Abstract: A hydromechanical torque sensor having several plenum chambers can be utilized to transmit torque between the driving and driven parts in the power train of a motor vehicle as well as to make necessary adjustments in a hydraulically adjustable transmission. To this end, the plenum chambers of the torque sensor can be connected to or sealed from each other. The torque sensor and the transmission can receive fluid from discrete sources or from a single source by way of suitable valves.

Abstract: For an electro-hydraulically actuable continuously variable belt transmission, the selected contact pressure at the movable conical pulley discs must be of such a magnitude that the chain, the force transmitting belt or the like does not slip. On the other hand, the contact pressure should not be too great for a high efficiency of the transmission to be achieved at every operating point. The invention reliably prevents slippage of the belt (chain, force transmitting belt or the like) by controlling the belt slip. The mean contact pressure is thereby reduced. As a result, there is a decrease in the mechanical and hydraulic losses at the transmission. A variant of the invention includes an embodiment of a rotational-speed sensor which makes it simultaneously possible to measure the axial position of the pulley disc(s). As a result, there is a reduction in the additional complexity required for slip control compared to the belt-tension control.

Abstract: A continuously variable transmission has springs, which urge the movable sheaves of primary-side and secondary-side pulleys, set to achieve a pulley ratio r.sub.1 approximate to or within a predetermined range of a neutral pulley ratio r.sub.N so that a vehicle takeoff response delay is eliminated when the driver shifts the transmission from a vehicle stop range (the P or N range) to the drive range (D range). This setting prevents a vehicle from moving backward when the driver shifts from the vehicle stop range to the D range immediately after starting the engine. The pulley ratio r.sub.1 can be achieved either before or after the minimum required fluid pressure is supplied.

Abstract: A continuously variable transmission includes a main shaft having a stepped portion in the vicinity of an end thereof, stationary and movable flanges, and a stopper for preventing a movement of the movable flange. The stepped portion of the main shaft, an end of the movable flange, and the stopper cooperate to define a space around the main shaft.

Abstract: A pulley, in particular for a continuously variable transmission, provided with two sheaves placed on a pulley shaft, at least one sheave being movable in the axial direction relative to the pulley shaft by movement structure. This movement structure includes at least one piston/cylinder assembly, and also fixing structure which fixes the movable sheave in the direction of rotation relative to the pulley shaft. According to the invention, the fixing structure is fitted at least inside a cylinder of the piston/cylinder assembly.

Abstract: A belt-type continuously variable transmission has a pulley side pressure control valve for controlling side pressures of driving and driven pulleys and a controller for controlling the pulley side pressure control valve. The controller has a correcting device for correcting a belt transmission torque calculated by a belt transmission torque calculator when the polarity of the belt transmission torque changes. The correcting device adds to the belt transmission torque for a predetermined time a correction value corresponding to a peak torque of the belt transmission torque arising at times of throttle opening and closing. That is, because the belt transmission torque is corrected in correspondence with the peak torque arising at times of throttle opening and closing, the side pressures of the pulleys are kept at suitable values at all times and slippage of the metal V-belt is prevented.

Abstract: A continuously-variable-ratio transmission ("CVT") of the band-and-sheave type capable of "torque control", so that what the operator demands, by movement of the accelerator pedal or other control member, is a particular driving torque applied to the ratio-varying components ("variator") A connection (21, 22) between at least one of the variator sheaves (3, 4) and its shaft (5) is torque-sensitive, so that torque at that sheave generates an axial force which is a function of the magnitude and direction of the torque to which the sheave is subjected. Examples are described in which the operating axial load, applied to the variator pulley units, comprises two parts--a first part to maintain traction between sheaves and band, and a second part related to the applied torque--and a variator using more than one band.

Abstract: A hydraulic control apparatus for a continuously variable transmission includes an inhibit valve that blocks the supply of hydraulic pressure to a reverse-drive brake during forward movement, and an inhibit solenoid valve that relieves the hydraulic pressure in a fluid passage acting on a spool of the inhibit valve so as to move the spool to the closed side and also relieves the hydraulic pressure in another fluid passage acting on a high-pressure regulator valve to urge the same to the low-pressure side, thereby increasing the high fluid pressure. This arrangement is able to improve the transient response of the control apparatus without providing additional pressure control valves as done in the conventional apparatus. The control apparatus can be manufactured with reduced number of components and at a relatively low cost.