Abstract: An automatic transmission control apparatus has first and second hydraulic servos for engaging forward and reverse driving friction engaging elements, respectively, a fluid pressure control unit, a range shift detector, and an electronic control unit. When the forward driving range is selected, the fluid pressure control unit supplies a forward driving range pressure to the hydraulic servo via a changeover valve operated by a signal pressure from a normal open-type solenoid valve, when the signal pressure is drained. When the reverse driving range is selected, the electronic control unit outputs a signal to magnetize the solenoid valve. The solenoid valve is thus turned on to discontinue the drain. The control apparatus thus prevents low pressure in the reverse driving range pressure to prevent delay of engagement of the clutch.

Abstract: The invention provides a control apparatus for an automatic transmission for carrying out neutral control and hill-hold control in a range that causes no slip of a hill-hold brake.

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: 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: An automatic transmission control apparatus has a vehicle speed detector, an accelerator pedal operation detector, a brake pedal operation detector, a clutch hydraulic servo that is neutral-controlled, a brake hydraulic servo that is hill holding-controlled, and a control device for controlling the fluid pressure supplied to the two servos. The control device selectively changes the start timing of the fluid pressure supply control. If it is determined that the vehicle is stopped and that the vehicle is not on an uphill, the control device causes a pressure reducing device and a pressure supplying device to simultaneously start reducing the fluid pressure supply to the clutch servo and supplying fluid pressure to the brake servo, respectively.

Abstract: A continuously variable transmission system includes a belt type continuously variable transmission unit which, in turn, is composed of a primary pulley and a secondary pulley wherein the torque transmitting direction is switched by torque circulation in changeover between forward and reverse travel. When a low mode is selected in a D range, a somewhat higher hydraulic pressure from a regulator valve is supplied, through a manual valve, to a secondary hydraulic servo, which moves one sheave of the secondary pulley, and a somewhat lower hydraulic pressure from a ratio control valve is supplied to a primary hydraulic servo which moves one sheave of the primary pulley. When the D range is switched to R range by the manual valve, the supplies of the above hydraulic pressures are reversed. With this arrangement, the relative axial forces on the pulleys are changed in switching between forward and reverse travel.

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 hydraulic control system for an automatic transmission to establish a predetermined stage by applying a first frictional engagement element and releasing a second frictional engagement element, comprising: a first hydraulic servo for actuating the first frictional engagement element; a second hydraulic servo for actuating the second frictional engagement element; change-over means for switching the feed of an oil pressure to the first hydraulic servo; signal pressure generating means for generating a signal pressure; and a pressure regulator valve for regulating the pressure to be fed to the second hydraulic servo.

Abstract: A continuously variable transmission system includes a belt type continuously variable transmission unit (CVT) wherein the direction of torque transmission is switched by torque circulation between a low mode and a high mode accompanied by a change in the axial forces on the pulleys of the CVT. In the Low mode of the D range, a comparatively high hydraulic pressure from a regulator valve is supplied to a Low clutch hydraulic servo via a low-high shifting valve and to a secondary hydraulic servo. In addition, a comparatively low hydraulic pressure from a ratio control valve is supplied to a primary hydraulic servo. These oil pressure feeds are reversed by the switching of the low-high shifting valve.

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: A belt type continuously variable transmission (CVT) and a planetary gear unit are combined in a continuously variable transmission system for an automobile to deliver an output from the output shaft in the normal and reverse directions with a neutral position therebetween. A control mechanism with a hydraulic circuit controls hydraulic pressure of primary and secondary hydraulic servos for controlling axial forces applied to respective primary and secondary pulleys of the belt type continuously variable transmission. When an axial force difference is produced between the primary pulley and the secondary pulley, the belt type continuously variable transmission changes its speed corresponding to a torque transmission direction and normal and reverse rotation directions.

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 hydraulic control system for an automatic transmission includes a regulator valve in a hydraulic circuit for supplying pressure to a servo of a frictional engagement element. The regulator valve has an input port, an output port and a drain port. A valve member of the regulator valve includes a pressure receiving area fed with a feedback pressure from the portion of the hydraulic circuit between the regulator valve and the servo, and another pressure receiving area selectively fed with pressure from a signal pressure source. A further pressure receiving area, having a surface area different from the another pressure receiving area, is constantly fed pressure from the signal pressure source.

Abstract: An oil pressure controller of an automatic transmission which is capable of supplying engaging pressures to hydraulic servos of two frictional engaging elements which require different engaging pressures by a single pressure governing valve with a good pressure governing accuracy. The oil pressure controller comprises a hydraulic power source (10), hydraulic servos (70 and 80), signal pressure generating means (20), a pressure governing valve (30) for governing an oil pressure (P.sub.s) from the hydraulic power source (10) by a signal pressure (P.sub.ACC) and a control valve (40). The pressure governing valve (30)has a pressure receiving face A.sub.1 to which the signal pressure is applied, a pressure receiving face A.sub.2 to which the engaging pressure (P.sub.s) is fed back in the opposite direction and a pressure receiving face (A.sub.

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.