Abstract: An accumulator fluid control system for a hydraulic servo in a vehicular automatic transmission includes an accumulator having a cylinder, a piston, a return spring, a chamber disposed in the cylinder, a first and second input ports connected to a first passage, an output port connected to a second passage, and a check valve for controlling the connection between the first and second passages through the second input port.

Abstract: A check valve and an orifice are situated in a feeder oil passage to an accumulator so that influence of drained oil from the accumulator is eliminated when a hydraulic servo is drained. The hydraulic pressure is supplied to the servo through the orifice, and to the accumulator with the feeder oil passage separate from the oil passage to the hydraulic servo with the check valve being opened. When draining, the hydraulic pressure in the hydraulic servo is drained quickly, however, the hydraulic pressure in the accumulator is drained gradually because the check valve is closed.

Abstract: A sequence valve for the first brake (B.sub.1) is installed, and the forward four speed modes are attained by two solenoid valves. At in the second speed mode of D range, hydraulic pressure is applied to the second brake hydraulic servo to restrain certain rotating element through the one-way clutch. After the application to the second brake hydraulic servo is completed, then the hydraulic pressure is applied to the sequence valve for the first brake, and through the sequence valve, the hydraulic pressure is applied to the first brake hydraulic servo. Accordingly, when up shifting from the first speed mode to the second speed mode, the shifting is conducted smoothly by the engagement of the second brake, after that the first brake is engaged. When up shifting from the third speed mode to the fourth speed mode, the first brake hydraulic servo is swiftly drained by the 3-4 shift valve.

Abstract: An automatic transmission hydraulic controller having a multiplicity of hydraulic servos for respectively controlling a multiplicity of frictional engagement elements. A hydraulic pressure to be supplied to the hydraulic servos is applied to accumulator chambers of a multiplicity of accumulators. A line pressure to be supplied to the hydraulic servos is produced by a primary regulator valve and an engine output pressure control valve is controlled by an electrical signal from a control section to produce a hydraulic pressure corresponding to the engine output. Each of at least two particular ones of the multiplicity of accumulators has a back pressure chamber formed at the rear of a piston. The pressure receiving area of this back pressure chamber and that of the corresponding accumulator chamber are substantially equal to each other.

Abstract: A hydraulic controller for an automatic transmission, having a band brake having a large stopping force based on a self-boosting effect against rotation in a self-binding direction and having a comparatively small stopping force against rotation in the unbinding direction, a modulator valve for producing a modulator pressure by reducing a line pressure, a band brake hydraulic servo having a brake engaging hydraulic chamber and a brake releasing hydraulic chamber. A line pressure is supplied to the band brake hydraulic servo to stop rotation in the self binding direction when a predetermined transmission speed is selected. The line pressure is also supplied the band brake hydraulic servo to stop rotation in the unbinding direction when another transmission speed is selected. A modulator pressure is supplied to the brake engaging hydraulic chamber to stop the rotation in the self-binding direction of the band brake and to allow the rotation in the unbinding direction when an intermediate speed is selected.

Abstract: The first and second emergency control valves are a back up device in case all solenoid valves are in failure (non electrified). When the first and second solenoid valves are all off due to wire disconnection and the like in case the manual valve is at the 3 range, a 1-2 shift valve is constrained by the first emergency control valve, so that the hydraulic control device becomes the third speed mode. In case t#e manual shift lever is at the 2 range and a 2-3 shift valve, the 2-3 shift valve are constrained by the first and the second emergency control valves, so that the hydraulic control device becomes the second speed mode. In case the manual shift lever is at the 1 range, the first emergency control valve is constrained, and the 2-3 shift valve is constrained by the second emergency control valve, so that the hydraulic control device becomes the first speed mode. When the manual valve is at the D range, the fourth speed mode is attained in case the first and second solenoid valves are all off.

Abstract: A reverse shift control device of an automatic transmission prevents reverse running of the automatic transmission, even though a manual shift lever is set to a reverse range, when the vehicle runs at more than a predetermined speed. Certain shift valves have ports to which line pressure is applied from the manual valve when set to reverse, and also have ports which communicate with a hydraulic servo of a frictional engaging component which is engaged when the vehicle travels in reverse. When the manual valve is set to reverse and the vehicle speed is more than a predetermined speed (for example, 7 km/h), respective pairs of the ports are disconnected due to the shifting of the shift valves based on the signal issued by a controller.

Abstract: An orifice is installed on an oil passage to a hydraulic servo for a direct clutch. In forward high speed running, a line pressure from the D range port of a manual valve is supplied to the hydraulic servo through an oil passage used for forward high speed running and a three way cock (non manual type). Then comparatively large amount of oil is supplied to the servo in accordance with the high speed running. In reverse running, the line pressure from the R range port of the manual valve is supplied to the servo through the orifice and the three way cock. Consequently, comparatively small amount of oil is supplied to the hydraulic servo.

Abstract: A hydraulic control device for an automatic transmission, having a gear ratio different from that of usual D range by a manual shift down from the D range to range 3 or 2, is mounted on an automobile. A first solenoid valve, a first shift valve and a second shift valve are connected so that the first solenoid valve controls the first and second shift valves. A second solenoid valve, a third shift valve and a down shift control valve are connected so that the second solenoid valve controls the third shift valve and the down shift control valve. Oil paths through which line pressure is applied in accordance with the range at which the manual valve is set are connected to certain shift valves, so that motions of the valves in the shift valves and the down shift control valve are constrained in accordance with the set range of the manual valve.

Abstract: A hydraulic servo regulating device of an automatic transmission, which according to the present invention applies enough line pressure quickly to a hydraulic servo and obviates a delay when the line pressure is to be drained, is disposed in an oil path between a shift valve and an accumulator. The device employs regulator valve which has an application port connected to a shift valve, a regulating port in selective communication with the application port, a first feedback port through which feedback pressure is applied to one end of a spool, a second feedback port through which feedback pressure is applied to the other end of the spool, a spring and a drain port connected to the regulating port. Furthermore, the regulating port communicates with a hydraulic servo through a first oil path, and an accumulator chamber through a second oil path having an orifice and branched off from the first oil path.

Abstract: A manual valve which is used for an automatic transmission is designed to be shortened axially.A port for reverse running and the ports for forward running are made on the same axial direction against ports for the port for line pressure application.A spool has; a first oil chamber which connects the port for line pressure application and the ports for forward running, a second oil chamber which connects the port for reverse running and the port for line pressure application or a drain hole, and a drain path connecting the ports for forward running and the drain portion.

Abstract: A hydraulic control device of an automatic transmission for a vehicle utilizes a shift valve for shifting at a high speed stage to prevent creeping and provide a hill-stop mechanism. The shift valve for shifting at the high speed stage has a port open to a forward clutch hydraulic servo, a port communicating with a brake hydraulic servo, and a port receiving modulator pressure from a modulator valve. A solenoid valve controlling the shift valve is in turn controlled by signals issued when the vehicle stops and begins to travel, and the modulator valve is controlled by a linear solenoid throttle valve. The modulator pressure is applied to the forward clutch hydraulic servo, and line pressure is applied to the brake hydraulic servo when the vehicle stops. Line pressure is applied to the forward clutch hydraulic servo and line pressure to the brake hydraulic servo is drained when the vehicle runs.

Abstract: A strainer is mounted in an oil passage within a valve body constituting the hydraulic control unit of an automatic transmission. The strainer includes a frame (4) fitted into the oil passage, a reticulate member (5) secured to the frame (4) so as to form a barrier across the oil passage, and a permanent magnet (8) secured by press-fitting or by bonding to frame at a position ahead of the reticulate member (5) in terms of the direction of working oil flow. Foreign matter contained in the working oil is removed by the reticulate member (5) while extremely small contaminants exhibiting a magnetic property, such as ferrous chips, that cannot be removed by the reticulate member (5) are removed by the magnet (8).

Abstract: A governor valve for a hydraulic controller in an automatic transmission, which is disclosed herein, comprises an adapter having a line pressure supply bore made therethrough, a cylindrical governor rotary shaft loosely fitted into the adapter sleeve and having a line pressure supply port made therein, the port including notches intersecting the axis at right angles, a centrifugal weight mounted on one end of the governor rotary shaft and having a return spring, and a spool adapted to slide within the governor rotary shaft with the weight being urged against one end thereof. In this governor valve, there are provided dirt and dust collecting means for preventing dirt and dust separated by a centrifugal action from collecting in the line pressure supply port during the stoppage of the governor rotary shaft so as to make the shaft stick.

Abstract: An automatic transmission locking mechanism for parking, including a cam rod provided in the front portion thereof with a cam of a predetermined shape and interlocked at the rear end thereof with a manual shift lever, a sleeve supporting and guiding the cam rod for smooth axial movement and a pawl provided with a detent which made to engage with the parking gear of an automatic transmission by the axial movement of the cam rod when the manual shift lever is shifted to place the automatic transmission in the parking range.

Abstract: An automatic transmission locking mechanism including a lever rotatively interlocked with a manual shift lever, a rod adapted to be advanced or retracted by the lever, a parking gear, a pawl with a detent having a detent to be engaged with the parking gear, a cam mounted on the rod for pushing up the pawl in shifting the manual shift lever to the parking position, a bracket on which the cam runs and a spring for releasing the pawl from the parking gear and for retaining the pawl at the released position, wherein the pawl is rotatably supported on a shaft of a reduced length and the spring is disposed near the free end of the pawl within a plane in which the pawl is turned on the shaft and thereby the locking mechanism is formed in a compact construction and is suitably applicable to a front-engine front-drive vehicle.

Abstract: An automatic transmission locking mechanism for parking, comprising a detent lever interlocked with and adapted to be turned by a manual shift lever, a rod adapted to be advanced or retracted by the detent lever, a cam slidably mounted on the rod and adapted to push a pawl having a detent to the operating position where the detent engages with a parking gear when the automatic transmission is placed in the parking range, a bracket on which the cam runs and a spring for disengaging the detent from the parking gear and for retaining the pawl at the released position. The spring is disposed in the vicinity of the free end of the pawl and within a plane in which the pole turns, with one end thereof engaged with the free end portion of the pawl and with the other end thereof fixed in a finished hole formed in a stationary part.

Abstract: An automatic transmission locking mechanism including a detent lever rotatively interlocked with a manual shift lever and provided with notches corresponding to the shift positions, respectively, of the manual shift lever for receiving the detent of a detent spring, a rod adapted to be advanced or retracted by the detent lever, a parking gear fixed to the output shaft of the automatic transmission, a pawl having a detent to be engaged with the parking gear in locking the parking gear, a cam slidably mounted on the rod and adapted to push the pawl for turning when the rod is advanced in shifting the manual shift lever to the parking position, a bracket on which the cam runs upward and a spring for releasing the pawl from the parking gear and for retaining the pawl at the released position. A contact surface formed in the free end of the pawl for engagement with the cam is formed so as to reduce the detrimental slip between the cam and the contact surface to the least possible degree.