摘要:
An automatic transmission has lower side and higher side friction engagement devices, with the lower side one being engaged and the higher side one being disengaged when a lower speed stage is engaged, while the lower side one is disengaged and the higher side one is engaged when the speed stage one higher than that lower speed stage is engaged. A control device for the transmission includes a shift valve for switching actuating fluid pressure between the lower side and the higher side friction engagement device and for draining the other one thereof, to provide the lower or the higher speed stage. An upshift smoothing valve is interposed in the drain path for the lower side friction engagement device for providing a higher flow resistance when a value representing engine output is relatively high and for providing a lower flow resistance when the value representing engine output is relatively low. Thus upshifting shock is reduced, particularly under low engine output conditions, in which overlapping of the engagement of the lower side and the higher side friction engagement devices is reduced. Optionally, the upshift smoothing valve may provide its higher or lower flow resistance, according as to whether the value representing engine output prevails over the actuating pressure for the higher stage friction engagement device, in a relationship between them, or not.
摘要:
In an automatic transmission comprising a fluid type torque converter having an input member including a pump vane wheel and an output member including a turbine vane wheel, and an auxiliary transmission having one or plural stages of gear trains through which the torque of said output member is transmitted to driving wheels, a lock-up control device for a torque converter in an automatic transmission for vehicle comprising a hydraulic direct coupling clutch having a slip characteristic provided between the input and output members of the torque converter and capable of mechanically coupling said both members and a modulator valve disposed in an oil passage for connecting an oil pressure cylinder of said direct coupling clutch with an oil pressure source, said modulator valve being composed of a valve body for opening and closing said oil passage, a spring for biasing said valve body in a valve-opening direction, a first oil pressure chamber for introducing pilot oil pressure for biasing said valve body in a valve-closing direction from an input port side of said modulator valve, and a second pilot oil pressure chamber for introducing pilot oil pressure for biasing said valve body in the valve-opening direction, wherein an output side of a device for generating oil pressure proportional to vehicle speed for releasing oil pressure which is changed proportional to the vehicle speed is connected through a throttle to said second pilot oil pressure chamber and a valve device for detecting the idle state of an engine throttle valve to release said second pilot oil pressure chamber to atmosphere is connected to said second pilot oil pressure chamber.
摘要:
A direct coupling clutch controller interposed between a direct coupling clutch in a torque converter of an automatic transmission and a hydraulic pressure source for temporarily disconnecting the direct coupling clutch whenever the transmission shifts gears. The controller is particularly suitable for transmissions having four or more gear stages, and includes a valve having a first and a second switching position where the pressure source is connected to the clutch. As the valve moves between the positions, the connection is interrupted. The valve is pilot operated by the transmission controller.
摘要:
In a transmission for an automotive vehicle, a control system is provided for controlling a direct-coupling mechanism for mechanically engaging input and output members of a hydraulic power transmission mechanism of the transmission. The control system includes a first sensor for detecting the value of a first parameter indicative of the engine load, and a control mechanism adapted to compare the value of the first parameter detected by the first sensor with a predetermined reference value for selectively engaging and disengaging the input and output members with and from each other through the direct-coupling mechanism. A second sensor detects the value of a second parameter indicative of the vehicle speed, and a reference value setting device sets the predetermined reference value to a value dependent on the value of the second parameter detected by the second sensor.
摘要:
A control device for controlling the operation of a direct-coupling hydraulic clutch of a hydraulic torque converter for use in an automotive vehicle, wherein the hydraulic torque converter is coupled to a transmission of the automotive vehicle selectable at a plurality of transmission gear ratios. A first fluid line is connected to the direct-coupling hydraulic clutch for supplying same with operating fluid pressure generated by an operating fluid pressure source. A selector valve is arranged across the first fluid line and shiftable to a first or a second position thereof in response to a transmission gear ratio established by the transmission, and is adapted to open the first fluid line when it assumes the first or second position, and to close the first fluid line when it assumes a third position between the first and second positions. A second fluid line branches off from the first fluid line at a location between the selector valve and the direct-coupling hydraulic clutch and communicates with a zone under lower pressure, and across which the selector valve is arranged. The selector valve has a valve operable to close the second fluid line when the first or second position is assumed, and to open the second fluid line to thereby escape operating oil pressure to the zone under lower pressure when the third position is assumed. Preferably, at least one restriction is arranged in the first fluid line at a location between the junction of the first and second fluid lines and the operating fluid pressure source.
摘要:
In an automatic transmission for a vehicle, a lock-up device is provided for a direct coupling clutch. The automatic transmission includes a fluid type torque converter having a hydraulic direct coupling clutch, and an auxiliary transmission having plural stages of gear trains. The lock-up control device has a valve for controlling the supply of oil pressure from a common oil pressure source to the direct coupling clutch, the valve having a body movable between opposite end positions and adapted to take a first switch position at one of the end positions when applied with a single signal pressure and a second switch position at the other end position, after release of the signal pressure, due to resilient force of a spring. The valve allows flow of the actuating oil pressure to the direct coupling clutch when the valve body is at both the first and second switch positions and interrupts the flow during shifting movement of the valve body from the first to second positions or vice versa. Thus, the direct coupling clutch is instantaneously disconnected during gear shifting operation over adjacent three gear ratios with use of the single signal pressure.
摘要:
A direct-coupling control system for torque converter in automatic transmission, comprising a fluid torque converter coupled in series to an auxiliary transmission capable of selectively switching a speed ratio over to one of a plurality of different stages and a direct-coupling mechanism capable of directly mechanically coupling together input and output members of the torque converter using the engaging capacity determined by the function of difference between the actuating pressure acting on the engaging side of the torque converter and the internal pressure acting on the release side thereof. The control system is also provided with a switch valve for allowing the actuating oil to escape to an oil tank synchronously with the speed change operation, and a supplementary mechanism for performing a switching operation so as to raise the internal pressure of the torque converter synchronously with the speed change operation. There is further provided with a supplementary oil passage for supplementing pressurized oil to the torque converter and a switch device for allowing the actuating oil to escape to the oil tank and opening the supplementary oil passage when the throttle opening is at an idle position.
摘要:
A direct-coupling control device for a torque converter for an automatic vehicular transmission in which a valve controlling the locking force of a direct-coupling mechanism is provided with two independently-formed pressure chambers pushing a valve body in a direction in which a locking force is increased. The device is also provided with a first fluid pressure output connected to one of the pressure chambers, and a second fluid pressure output connected to the other. When the first fluid pressure is higher than the second fluid pressure, the first fluid pressure acts on the sum of the individual working areas of the first and second fluid pressures on the valve body. A reliable speed change control can be provided by the two fluid pressures, and the capacity characteristics of the direct-coupling mechanism can be selected optimally with respect to these fluid pressures. The locking force of the direct-coupling mechanism can be increased quickly in proportion to increasing vehicle speed, and fuel costs can be reduced very effectively.
摘要:
A direct-coupling controller for a torque converter direct-coupling clutch in an automatic transmission. The controller can include a feedback pilot oil pressure operated reduction valve with a throttling orifice in the signal line and a pilot oil pressure switched vehicle speed response valve in parallel with the reduction valve. The vehicle speed response valve bypasses the reduction valve when vehicle speed is above a predetermined value. Alternatively, the controller includes a single valve which is pilot oil pressure switched depending on vehicle speed which in an open position directly feeds oil pressure to the clutch and which in a closed position feeds the oil pressure to the clutch while throttling the oil pressure through an orifice and permitting some of the working oil to pass the drain through another throttling orifice.
摘要:
In an automatic transmission which prevents creep in advance speed change gear trains and which makes it possible to apply engine brake in the advance speed change gear trains, the invention provides a creep prevention apparatus for a car equipped with an automatic transmission which ensures effective engine brake even if control elements for the creep prevention mechanism are out of order by accident.