Abstract: A shift control system for an automatic transmission, includes: a plurality of frictional engagement elements adapted to be hydraulically engaged for setting a plurality of gear stages; and a shift lever for switching between an automatic mode, in which a gear stage is set on the basis of the running state of a vehicle, and a manual mode in which a gear stage is selected by manipulating the shift lever. A shift detector detects that a gear stage should be selected for the shift in the manual mode state and a shift start timing adjuster, if the shift in the manual mode state is detected, the switching rate of the frictional engagement elements which are switched for executing the detected shift.

Abstract: A method is provided for the control of servo hydraulic pressure in an automatic transmission. Servo hydraulic pressure is adapted to engage or release first and second frictional engagement elements arranged in such a relationship that, upon shifting from one particular speed stage to another, one of the first and second frictional engagement elements is released while the other is engaged. The servo hydraulic pressure, engaging one frictional engagement element, is linearly lowered in a torque phase during a shift so it releases the one frictional engagement element, responsive to a rise in the servo hydraulic pressure to the frictional engagement element to be engaged, to maintain an inversely proportional relationship between the servo hydraulic pressure being raised and that being released.

Abstract: In a certain speed stage shifting of an automatic transmission of a vehicle including a speed change gear mechanism including rotary members such as gears and gear carriers and hydraulically operated friction engaging brakes and clutches adapted to provide various speed stages according to selective engagement and disengagement of the friction engaging brakes and clutches, the servo oil pressure of a first friction engaging brake is immediately lowered down to a stand-by pressure marginally higher than a threshold pressure bordering non sliding and sliding of the first friction engaging brake at the start of a change-over of a second friction engaging brake is and then, when a substantial change-over of the second friction engaging means started, the servo oil pressure is further lowered across the threshold pressure and thereafter periodically lowered by a decrement the magnitude of which may desirably be increased along with a lapse of time.

Abstract: A control system is provided for servo hydraulic pressure in an automatic transmission having planetary gear mechanisms. Shifting elements of the mechanisms can be connected to establish a different power flow in accordance with engagement or release of frictional engagement devices under the control of servo hydraulic pressure to achieve plural speed stages. The system comprises first and second frictional engagement devices engageable simultaneously in a reverse range, first and second servo pressure feed lines for feeding servo hydraulic pressure to the devices, a regulator valve disposed in the first line, a solenoid for controlling the valve, an electronic control unit for outputting a signal to the solenoid, and a detector for detecting shifting to the reverse range. The valve is controlled by the solenoid in accordance with an output from the unit upon detection of shifting to the reverse range by the detector, whereby engagement of the first device is coincided with that of the second device.

Abstract: A shift control system controls an automatic transmission of a vehicle wherein half-lock-up control for a lock-up clutch is executed when the running state of the vehicle is in a predetermined operative range.

Abstract: A control system is provided for servo hydraulic pressure in a vehicular automatic transmission having planetary gear mechanisms. Shifting elements of the mechanisms can be connected to establish a different power flow in accordance with engagement or release of frictional engagement devices under the control of servo hydraulic pressure to achieve plural speed stages. The system comprises a servo pressure feed line for feeding, even in a non-running range, servo hydraulic pressure to at least one particular device out of plural frictional engagement devices which are caused to simultaneously engage in a reverse range of the transmission, a directional control valve disposed in the line to control feed or drain of the servo hydraulic pressure to or from said particular device through the line, and a solenoid valve for controlling the control valve to prevent the feed of the servo hydraulic pressure at vehicle speeds above a predetermined value.

Abstract: A rotary element engaging device of an automatic transmission includes a stationary member, a planetary gear set having rotary elements, a frictionally engaging element interposed between the stationary member and one of the rotary elements, a one-way clutch interposed between the stationary member and the one rotary element, and an operating member for engaging and disengaging the frictionally engaging element. The rotary element is adapted to be selectively engaged with the stationary member through two paths formed of the frictionally engaging element and the one-way clutch. The one-way clutch is disposed between the frictionally engaging element and the operating member. The one-way clutch includes an inner race connected to the one rotary element and an outer race fixed to the stationary member. The operating member is adapted to act on the frictionally engaging element through the outer race.

Abstract: A five-speed automatic transmission includes a main transmission and an over-drive transmission of a front disposition type. The main transmission includes three sets of planetary gears, a clutch for engaging and disengaging speed-change elements of the planetary gear sets, and a brake for fixing and releasing the speed change elements, and provides for four forward speed ranges and one reverse speed range. In the over-drive transmission of a front disposition type, a speed change element of an over-drive planetary gear set connected to an input element of the main transmission is adapted to be engaged, disengaged and fixed for achieving either a directly coupled stage or an over-drive stage. The over-drive transmission releases the direct coupling for reverse driving operation. One of the clutches of the main transmission for achieving the directly coupled stage and one of the brakes for achieving the low speed stage are engageable in the reverse driving operation.

Abstract: A linear solenoid valve apparatus includes a linear solenoid housed within a valve body. The linear solenoid valve includes a sleeve with an open channel conduit on its exterior surface, an exhaust port in communication with the open channel in the lower portion of the sleeve, a feedback port, a spool and a spring. The valve body includes a supply passage connecting with the open channel, off center at the top of the sleeve. The structure is designed to prevent the valve from sticking.

Abstract: A control system of an automatic transmission for determining and setting a gear stage on the basis of at least two of the parameters including a vehicle speed and a throttle opening. The control system comprises: a first detector for detecting a first parameter; a second detector for detecting a second parameter; a gear stage memory for determining and storing speed stage areas for holding the gear stages individually in terms of the first and second parameter and any two speed stage areas in a partially overlaid manner; a shift decider for determining a shift to be executed, on the basis of the first parameter outputted from the first detector, the second parameter outputted from the second detector, and the stored content of the gear stage memory; and a gear stage determiner for determining a gear stage to be set, if there are a plurality of gear stages determined by the first parameter and second parameter detected, at any of the gear stages.

Abstract: An automatic transmission which includes a device for selecting and temporarily setting such one of other speed stages, if any, between a present speed stage and a target speed stage as can have a small number of fluctuating revolutions of rotary members of planetary gear sets of the automatic transmission and two or less frictional engagement elements to be switched.

Abstract: A linear solenoid valve apparatus includes an electromagnetic valve, a modulator valve with a valve sleeve, valve spool, a spring biasing the spool, a feedback pressure chamber, and an adjusting means provided between the electromagnetic valve and the modulator valve so that the plunger position corresponding to the value of suction power coincides with the spool position.

Abstract: In controlling an automatic transmission in a vehicle by a combination of an electronic computer system and a hydraulic actuation system according to a principle of feedback control so that the electronic computer system computes a target control state for the hydraulic actuation system and the hydraulic actuation system is operated according to a difference between the target control state and a current control state thereof, the difference is modified by an amount which is decreased along with lapse of time so that the delay in the operation of the hydraulic actuation system is compensated for by a simulation that at the start of control the difference is beforehand increased for an amount which is gradually cancelled by a delay function of the difference itself as the delay in the operation of the hydraulic actuation system disappears. The difference may further be modified so that the modification is started with a time lag. The difference may further be modified by the rate of change of itself.

Abstract: A control system in an automatic transmission for controlling the change-over of the three speed change patterns which are a speed change pattern having a cross gear ratio on a low speed side, a speed change pattern having a cross gear ratio on a high speed side and a speed change pattern having a normal gear ratio. According to this controlling system, when one of the three speed change pattern is selected based one a throttle opening and a vehicle speed, and when it is judged that the gear shift from a speed range in the present speed change pattern to a speed range in the selected speed change pattern falls under on of prohibited conditions, e.g., requiring engagement and/or disengagement of three or more frictional engaging elements for the gear shift, the gear shift is performed using a temporary speed change pattern (including the present speed change pattern) including a speed range not falling under the prohibited conditions.

Abstract: In an automatic transmission in a vehicle having a tandem connection of a first gear unit such as lower and upper gear stages and a second gear unit such as having three gear stages so that selective engagement and disengagement of clutches and brakes in each gear unit selectively provide six gear states, a certain clutch or brake of the first gear unit is controlled in reference to a difference between certain target engaged/disengaged condition and actual engaged/disengaged condition of itself in setting up a certain gear stage in the first gear unit as well as to difference between certain target engaged/disengaged condition and actual engaged/disengaged condition of (and further, though optionally, a signal for controlling) a certain clutch or brake of the second gear unit in setting up a certain gear stage in the second gear unit.

Abstract: A linear solenoid valve apparatus for discharging foreign matter collected at the exhaust port by engaging the electromagnet of the linear solenoid valve. The apparatus includes a linear solenoid valve having a valve sleeve, a spool, a spring, and an electromagnet, and a modulator valve including an exhaust port in which foreign matter is collected. The electromagnet is energized by foreign matter discharging control, responsive to detection of lack of need for output pressure from the solenoid valve, so that the foreign matter is discharged from the exhaust port.

Abstract: An automatic transmission with a reverse inhibit feedback passage between front and rear oil sumps. The transmission includes a case, a passage in the case for returning oil to the front sump from the rear sump and a flap valve for allowing the flow from rear sump to front sump while inhibiting oil flow in the reverse direction.

Abstract: A shift control system and method for use in an automatic transmission includes a plurality of frictional engagement elements and a gear train settable to a plurality of speed stages of different gear ratios according to the engagement/release states of the frictional engagement means and having a plurality of different engagement/release combinations for the frictional engagement elements to set a predetermined one of the speed stages. A shift decision unit decides a shift to be performed. A speed stage selection determines a speed stage to be set after the shift. An engagement/release pattern selects and outputs one of the engagement/release combinations of the frictional engagement elements for setting a speed in which either the current speed stage or the speed stage to be set after the shift is the predetermined speed stage, wherein two or less of the frictional engagement elements have their engagement/release states switched during the shift.

Abstract: A shift control system for use in an automatic transmission having a gear train to be set to a plurality of gear stages of different gear ratios in accordance with the engagement/release states of a plurality of fricitional engagement devices. The gear train is enabled to set a predetermined gear stage in accordance with plural kinds of combination of the engagement/release of the frictional engagement devices. The shift control system comprises: an input torque detector for detecting input torque to be inputted to the gear train; a torque evaluator for evaluating the level of the input torque; and an engagement/release pattern selector for selecting the combination of engagement/release of the frictional engagement devices for setting the predetermined gear stage, on the basis of the result of the input torque evaluated by the torque evaluator.

Abstract: A shift control system for use in an automatic transmission which comprises: a plurality of frictional engagement components; and a gear train adapted to set a plurality of speed stages having different gear ratios in accordance with the combination for engagement/release of the frictional engagement components and enabled to select a combination for engaging and releasing any of the frictional engagement components as that for engagement/release of the frictional engagement components for setting any of the speed stages.