Abstract: A vehicular automatic transmission, for establishing a plurality of forward gear stages, includes: a transmission case; an input shaft; a transmission mechanism connected to the input shaft and including a plurality of transmission elements; an output shaft connected to the transmission mechanism; a clutch drivably connecting any one of the input shaft and the transmission elements individually; and a hydraulic servo for applying the clutch responsive to an oil pressure. The transmission case encloses the transmission mechanism, the clutch and the hydraulic servo, and includes axial end walls, on one of which is formed a stationary cylinder for the hydraulic servo. A piston is slidably mounted in the cylinder and together with the cylinder, defines an oil chamber for receipt of the actuating oil pressure. A bearing is arranged between the piston and the clutch for transmitting the thrust force from the piston to the clutch, while allowing relative rotation between the piston and the clutch.

Abstract: A band brake drum supporting device for an automatic transmission having a band drum to be retained in a case by fastening a band brake which is joined to a rotary element of the automatic transmission and arranged in the case. The drum includes a band engaging portion and a cylindrical drum supporting portion extending radially inward from the band engaging portion while being offset axially with respect to the band engaging portion. The outer circumference of the drum supporting portion is supported through two axially juxtaposed bearings on a stationary support portion which extends radially outward of the drum supporting portion from the case. The stationary support portion includes a cylindrical boss portion disposed coaxially with the drum supporting portion and engaging at its inner circumference with the two bearings and a planar flange portion extending radially outward from the end portion of the boss portion which is located closer to the band brake.

Abstract: A control system for use in an automatic transmission which includes a gear shift mechanism having first and second frictional engagement elements for establishing: a first gear stage with the first frictional engagement element being applied and the second frictional engagement element being released; and a second gear stage with the first frictional engagement element being released and the second frictional engagement element being applied. The control system, in turn, includes: a first oil passage for feeding an oil pressure to the first frictional engagement element; a second oil passage for feeding an oil pressure to the second frictional engagement element; and a first valve arranged in the first oil passage for regulating the oil pressure of the first oil passage. At the time of a shift from the first gear stage to the second gear stage, the oil pressure of the first oil passage is regulated by the first valve responsive to the oil pressure of the second oil passage.

Abstract: A control system for an automatic transmission, has a fluid transmission unit for transmitting the rotation of an engine to a speed change unit; a clutch adapted to be applied when a forward running range is selected to transmit the rotation of the fluid transmission unit to the transmission mechanism of the speed change unit; a stopped state detector for detecting a stopped state of a vehicle wherein the stopped state is defined as a forward running range being selected, the throttle opening being fully closed, the brake pedal being depressed, and the vehicle speed being substantially zero; engine speed detector for detecting the engine speed; clutch operation force generating means for generating the application force of the clutch; and a control unit. The control unit releases the clutch by reducing the engaging force of the clutch when the stopped state of the vehicle is detected by the stopped state detecting means.

Abstract: An automatic transmission control apparatus has an input clutch, a hydraulic servo for the clutch, a fluid temperature detector, an engine start detector, a range shift detector, and a control device for controlling the fluid pressure supply to the hydraulic servo. The control device raises the fluid pressure supply to the hydraulic servo on the basis of predetermined rising characteristics in normal operation. When it is determined that the shift has been performed for the first time since the start of the engine and it is determined that the fluid temperature is lower than a predetermined temperature, the control device rapidly raises the fluid pressure supply to the hydraulic servo up to the required engaging pressure.

Abstract: A control system for an automatic transmission includes a clutch for transmitting the rotation of an engine to the transmission and a hydraulic servo for applying/releasing the clutch. A starting state is determined by satisfaction of at least one of the following conditions: the throttle opening is not fully closed; the brake pedal is released; and/or the vehicle speed is substantially above zero. Sensors detect the throttle opening of the engine and the applied/released state of the clutch and send signals to a control unit. A hydraulic controller controls the oil pressure fed to the hydraulic servo. When the starting state is detected, the control unit detects the actual applied/released state of the clutch to determine the difference between the applied/released state and a predetermined ideal applied/released state to set an oil pressure correction according to that difference.

Abstract: A 5-speed automatic transmission for a vehicle having a highly efficient top gear, a compact construction and a wide overall range of gear ratios. The automatic transmission has a speed changer which provides five gear stages, namely two speeds on the speed decreasing side and two speeds on the speed increasing side with a direct-coupled gear therebetween. The speed changer includes a ring gear connected to an output shaft, a first carrier, a first sun gear, a second carrier connected to the first carrier, a stepped pinion gear supported by these two carriers, and a sun gear meshing with the pinion gear. The first carrier is connected to an input shaft by a clutch and the first sun gear is connected to the input shaft by a clutch. The first sun gear may be stopped by a first brake, a second brake stops the second sun gear and a third brake is provided to stop a third sun gear. Top gear is achieved by meshing of the pinion gear with the second sun gear and the ring gear.

Abstract: A shift control system of an automatic transmission for setting a predetermined gear stage by applying first frictional engagement means and releasing second frictional engagement means, comprising: a pressure regulating mechanism for regulating an oil pressure to be fed to or drained from the first frictional engagement means; a failure detector for detecting a failure of an apparatus to participate in the regulation and control of the oil pressure which is to be fed to or drained from at least one of the first and second frictional engagement means: and a gear stage inhibitor for inhibiting the setting of the predetermined gear stage if the failure is detected by the failure detector.

Abstract: The automatic transmission equipped with the control system of this invention is combined with a coupling for transmitting the rotation of the engine to the transmission and includes: a clutch which is applied when a forward running range is selected; a hydraulic servo which receives an oil pressure for applying the clutch; and a hydraulic control unit for controlling the oil pressure to the hydraulic servo.

Abstract: A control system for control of a clutch interposed between a fluid transmission unit and a speed change unit in a vehicular automatic transmission. The control system includes a first R.P.M. detector for detecting clutch input side R.P.M. and a second R.P.M. detector for detecting clutch output side R.P.M. A stop state detector determines if the vehicle is at a standstill and a starting operation detector detects a starting operation by the driver.

Abstract: A system and method for controlling an automatic transmission in a vehicle drive train including an engine, the automatic transmission and a fluid coupling for transmitting the rotation of the engine to the transmission. The transmission includes a clutch applied when a forward running range is selected; a second one-way clutch which is applied, when the first clutch is applied, to establish a forward 1st speed; and a brake for locking the one-way clutch, when applied, to block the reverse rotation of the output shaft of the transmission. A first hydraulic servo receives a first oil pressure for applying the first clutch and a second hydraulic servo receives a second oil pressure for applying the brake. When a forward running range is selected, with the vehicle stopped, the engine idling and a foot brake engaged, the oil pressure of the first hydraulic servo is lowered from the oil pressure at the 1st speed whereas the oil pressure of the second hydraulic servo is raised to a modulated pressure.

Abstract: A control system for an automatic transmission including a main transmission unit for setting a reverse stage and a plurality of forward stages and an auxiliary transmission unit connected in series to the main transmission unit and capable to be changed between two higher and lower stages. The control system comprises: a solenoid valve for outputting a signal pressure when at least the reverse stage and a predetermined one of the forward stages are to be set; a change-over valve for changing the signal pressure selectively into a signal pressure for setting the auxiliary transmission unit to a high gear stage and a signal pressure for controlling an engine braking state; and an engine braking control valve for controlling an engine braking frictional element at the predetermined forward stage into a released state in response to the signal pressure coming from the change-over valve.

Abstract: A shift mechanism for an automatic transmission includes a frictional engagement element arranged between the case of the automatic transmission and one element of a planetary gear unit and a hydraulic servo unit for engaging the frictional engagement element. A one-way clutch is connected to that same one element of the planetary gear unit for selectively locking it to the case. The one-way clutch is axially spaced from the frictional engagement element with the hydraulic servo unit therebetween. Further, the one-way clutch has its outer race connected to the case and its inner race connected to the aforementioned element of the planetary gear unit through a connection member axially extending along the inner circumferential side of the hydraulic servo unit. The inner race is formed with a radial lubricating oil passage in fluid communication with an oil passage in a transmission shaft.

Abstract: A control system for an automatic transmission includes a first frictional engagement element and a second frictional engagement element; and a first hydraulic servo for controlling the application/release of the first frictional engagement element and a second hydraulic servo for controlling the application/release of the second frictional engagement element. A regulator valve regulates the oil pressure to the first hydraulic servo. A signal pressure is applied to the regulator valve to establish a predetermined gear stage by switching the applied/released states of the first frictional engagement element and the second frictional engagement element by feeding/releasing oil pressure to/from the first hydraulic servo and the second hydraulic servo.

Abstract: A control system for an automatic transmission, having a fluid transmission unit for transmitting the rotation of an engine to a speed change unit. The control system includes a clutch which is applied responsive to selection of forward running range; a one-way clutch which is locked, when the clutch is applied, to establish a forward first speed; a brake for locking the one-way clutch, to block reverse rotation of the output shaft of the speed change unit. First and second hydraulic servos apply, respectively, the clutch and the brake responsive to receipt of oil pressures. A control unit controls the oil pressures fed to the first and second hydraulic servos. The control unit starts the feed of oil pressure to the second hydraulic servo responsive to selection of a forward running range, provided the vehicle is substantially stopped, the engine is idling and the foot brake is engaged.

Abstract: A shift control system for shifting an automatic transmission from a predetermined gear stage to another by draining an oil pressure from predetermined frictional engagement element to release the same frictional engagement element and by feeding the oil pressure to another frictional engagement element to engage the same frictional engagement element while controlling the drain oil pressure of the frictional engagement element to be released and the engaging oil pressure to the frictional engagement element to be engaged. The shift control system includes an engine racing detector for detecting the racing of the engine while the transmission is being shifted in a clutch-to-clutch manner, and a hydraulic control circuit for controlling at least one of the drain oil pressure and the engaging oil pressure, on the basis of the degree of racing of the engine, as detected by the engine racing detector, such that the amount of racing of the engine falls within a predetermined range.

Abstract: First and second hydraulic servo units operate respective frictional engagement elements in a transmission and each includes first and second cylinders, each having a side wall portion interposed between the two frictional engagement elements. The first cylinder has first outer and inner cylinder portions and the first hydraulic servo unit further includes a first piston having inner and outer cylindrical surfaces slidably supported by the first outer and first inner cylinder portions of the first cylinder for reciprocating axial motion into and out of engagement with one frictional engagement element. First return springs are arranged radially inward of the one frictional engagement element for returning the first piston.

Abstract: A controller for an automatic transmission which reduces wear of frictional engagement elements and shortens gear change time even when a gear change jump is made. The controller of the present invention includes a first hydraulic servo to which oil is supplied to make a gear change jump, a second hydraulic servo to which oil is supplied to make a gear change to an intermediate gear stage, a limited supply oil circuit having an oil flow limiting element, a quick supply oil circuit bypassing the oil flow limiting element and a pressure governor for regulating a line pressure to supply oil at a controlled pressure to the quick supply oil circuit. An oil path switching valve switches oil supply, to the first hydraulic servo or the second hydraulic servo, between the limited supply oil circuit and the quick supply oil circuit.

Abstract: An transmission control unit includes a sensor for detecting a vehicle condition, a traffic condition monitor for determining whether or not traffic is heavy, a transmission pattern selector, and a transmission controller. The traffic condition monitor adds or subtracts a predetermined value in response to vehicle speed detected at set intervals of time so as to provide a vehicle speed value. The heavier the traffic, the larger the additional value. Also, the lighter the traffic, the larger the subtractive value. The vehicle traffic value is used in order to determine how heavy the traffic is.

Abstract: A control system for an automatic transmission, which receives the rotation of the engine through a fluid coupling, and which has a clutch applied when a forward running range is selected and released when a neutral range is selected and a range selecting mechanism for selecting a range. The control system includes a range detector for detecting the selected range, a hydraulic circuit and a control unit. The hydraulic circuit includes a hydraulic servo which is fed an oil pressure for applying the clutch and a manual valve movable between at least a forward range position for generating a forward range oil pressure and a neutral range position, by operation of the range selecting mechanism. A regulator valve regulates the forward range oil pressure to generate a regulated oil pressure.