摘要:
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. Since the rotational state of the engine being shifted is controlled by hydraulic control of the frictional engagement elements participating in the clutch-to-clutch shift, it is possible to reliably prevent any excessive racing of the engine and to prevent reduction of output shaft torque due to the tie-up of the frictional engagement elements.
摘要:
A control system is provided for servo hydraulic pressure in an automatic transmission having planetary gear mechanisms. First and second frictional engagement devices, whose servo pressures are reversed in feed/drain relationship between desired two high speed stages, are controlled by a shift valve and a directional control valve. The shift valve is switched by a first solenoid. The directional control valve is interposed in a servo hydraulic pressure feed/drain line communicating the shift valve with the first frictional engagement device and is controlled by a second solenoid. The first and second solenoids are controlled by an electronic control unit in accordance with a shift position detected by a detector, whereby the timings of feed or drain of the servo hydraulic pressures to or from the first and second frictional engagement devices are changed by predetermined relative amounts, respectively.
摘要:
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.
摘要:
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.
摘要:
An automatic transmission comprising a torque converter and a change speed transmission having a plurality of planetary gearsets and friction elements is provided with an input shaft supported by a transmission case. On the input shaft is mounted a small-diameter first drum. In the first drum are mounted a first clutch having a clutch piston, friction plates, separate plates and a clutch hub. On the input shaft is further mounted a large diameter second drum, in which are disposed a second clutch having a clutch piston, friction plates, separate plates and a clutch hub.The friction plates and separate plates in the second drum are disposed radially outside on top of the friction plates and separate plates in the first drum.
摘要:
A direct coupling clutch being assembled within a casing of a fluid coupling having an impeller mounted on the casing and a turbine supported on an output shaft of the fluid coupling. The direct coupling clutch includes a piston mounted slidably on a turbine hub in axial direction for engaging with and disengaging from a front cover of the casing and a damper device resiliently connecting the turbine hub and piston. The damper device includes an annular driven plate consisting of two guide plates secured concentrically with each other and having a first set and a second set of spaces arranged in double rows along two concentric circles, an annular drive plate having a set of openings arranged in a row along a first circle, a set of projections arranged in a row along a second circle, a first coil spring inserted in each of the first set of spaces and within each of the set of openings and a second coil spring inserted in each of the second set of spaces and between the projections. The first coil spring is continually compressed by the relative rotation of the drive and driven plates and the second coil spring having a greater spring constant than that of the first coil spring is compressed after the first coil spring has been compressed in a predetermined value.
摘要:
In a torque converter, in order to reduce the cost, simplify the manufacturing process and ensure the centering precision of of the stator relative to the outer race of a one-way clutch, the stator and the outer race of the one-way clutch have first engaging surface portions preventing relative rotation therebetween and second engaging surface portions providing concentricity therebetween. The first and second surface portions are axially offset from each other.
摘要:
In order to improve transmission efficiency of an automatic transmission, an engagement brake which does not cause drag is used and the surety of its engagement and release, and quick switching between forward maneuver and backward maneuver, is enabled. The automatic transmission comprises a transmission mechanism to achieve forward maneuver and backward maneuver. A backward motion brake which stops the rotation element to achieve backward maneuver is the engagement brake and an input clutch to transfer power by meshing with the rotation element during both forward maneuver and backward maneuver is a friction clutch. The control apparatus executes the control operation to prepare for speedy re-meshing by holding a supply pressure for the clutch hydraulic servo at a sufficient oil pressure to place the pressure in the stand-by condition at the piston stroke position immediately before the start of clutch engagement during the engagement or releasing of engagement of the engagement brake at the time of D.fwdarw.R or R.fwdarw.D shift.
摘要:
A control system for use in an automatic transmission having a transmission mechanism for establishing a plurality of forward stages, a neutral state and a reverse stage. The transmission mechanism includes a predetermined rotary element to be retained for establishing the reverse stage; a reverse brake for retaining the rotary element; and a frictional engagement element capable of stopping the rotation of the rotary element. The reverse brake is a meshing type brake which meshes with and retains the rotary element. The control system has an engagement mechanism for applying the frictional engagement element. When the reverse stage is selected, the frictional engagement element is applied at least until the meshing engagement of the reverse brake is established, to stop the predetermined rotary element.
摘要:
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. The control system further includes a second valve arranged in the first oil passage for selectively feeding or shutting off the oil pressure of the first oil passage to and from the first frictional engagement element.