Abstract:
An automatic engine stop/restart-type vehicle and control method determine whether a vehicle is in a non-running range. The vehicle comprises: an engine; a transmission, an oil pump and a controller. The transmission has a coupling element that transmits an output torque of the engine. The oil pump supplies a hydraulic pressure to the transmission. The controller controls an output from the engine; controls the hydraulic pressure supplied to the transmission; and determines whether the engine is in an automatic stop state when a manually set mode of the transmission is shifted from a non-running range to a running range. A hydraulic pressure compensation procedure is performed to conform friction coupling characteristics of the coupling element and input characteristics of the transmission with each other if the controller determines that the engine is in the automatic stop state.
Abstract:
A method for controlling gear shifting of a transmission in a vehicle. The transmission is supplied with electric power from a battery or an alternator and drives an actuator to shift gear ranges of the transmission. The transmission has an output shaft that becomes difficult to rotate if a predetermined range is selected when the engine stops running. The method includes determining whether a gear range differing from the predetermined range is selected when the vehicle stops traveling, and forcibly shifts the gear range to the predetermined range when a gear range differing from the predetermined range is selected by driving the actuator with electric power supplied from the alternator.
Abstract:
A compact automatic transmission for a vehicle capable of preventing increase in relative rotational speed between shift elements. A planetary gear unit is provided with a sun gear to which rotation of an input shaft is input, a carrier that can be stopped from rotating, and a ring gear for outputting, to a planetary gear set, rotation that is reduced in speed relative to that of the input shaft. A clutch is connected/disconnected, the input shaft and the sun gear are appropriately connected/disconnected, and the carrier is appropriately stopped/unstopped by a brake and a one-way clutch. This prevents relative rotational speed between shift elements of the gear unit that does not participate in a shifting operation from excessively increasing. When the clutch is disposed between the input shaft and the sun gear, the torque capacity of the clutch can be reduced as compared with the case where it is disposed between the gear unit and the gear set. Therefore, the clutch can be formed into a more compact structure and the overall automatic transmission can be made more compact.
Abstract:
A gear having high pitching resistance, sufficient surface hardness, sufficient hardened depth, high abrasion resistance, high breakage resistance, high fatigue resistance, and low gear noises. A material equivalent to JIS-SCM420 is soft nitrided for two hours in a mixture gas containing 45 to 65 volume % of residual NH.sub.3 at a gas temperature of 530 to 565.degree. C., thus producing a compound layer having a hardness equal to or higher than that of the material plus Hv 50 and a thickness of 200 .mu.m or more.
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. 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.
Abstract:
An automatic transmission for a vehicle, as provided a plurality of planetary gear units in which the ratios of the tooth numbers of the sun gears to the tooth numbers of the ring gears are different from each other. In the two sets of planetary gear units in which the ratios of the tooth numbers of the sun gears to the tooth numbers of the ring gears are different from each other, the ring gears are identical to each other in the tooth number, the normal module, the normal pressure angle, the angle of torsion, the pitch radius, the base radius, the bottom diameter, the top diameter, the tooth height, the dedendum, the addendum, the lead, the coefficient of normal shift and the arcuate tooth thickness, and the pinions of those two sets of planetary gear units are identical to each other in at least the arcuate tooth thickness, the coefficient of normal shift, the dedendum, the addendum, the tooth height, the angle of torsion, the normal pressure angle and the normal module.
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:
A control system for an automatic transmission, comprising a gear transmission unit for establishing a predetermined gear stage by applying a plurality of frictional engagement elements selectively. The gear transmission unit includes a main transmission portion capable of establishing at least a reverse gear stage, and an auxiliary transmission portion capable of switching a high gear stage and a low gear stage. The auxiliary transmission portion is set to the high stage at the shifting time to the reverse stage. The reverse stage is established by controlling the application of predetermined frictional engagement elements of the main transmission portion when a reverse stage shifting command is generated. A torque-down of an engine is executed at the time of controlling the engagement of the frictional engagement elements for the reverse stage. The auxiliary transmission portion is set to the high stage by controlling the applications of predetermined frictional engagement elements of the auxiliary transmission portion when the reverse stage in the main transmission portion is detected. A signal to end the engine torque-down is sent when a shift of the auxiliary transmission portion to the high stage is detected.
Abstract:
A hydraulic control circuit for an automatic transmission which has a plurality of hydraulic type frictional engagement elements for switching gear stages and a lockup clutch juxtaposed to a hydraulic power transmission device for transmitting engine power to the gearing. The hydraulic control circuit includes a lockup relay valve for switching oil pressure between an application side oil chamber and a release side oil chamber of the lockup clutch to apply and release the lockup clutch and a lockup switching valve for switching the lockup relay valve. A lockup control valve functions to increase the pressure difference between the application side oil chamber and the release side oil chamber at the time of application of the lockup clutch, as a signal pressure rises. A transient pressure control valve controls the transient pressure of a hydraulic frictional engagement element in accordance with the signal pressure. A single linear solenoid valve regulates the signal pressure fed both to the lockup control valve and to the transient pressure control valve. A signal pressure relay valve has a first output port connected to the lockup control valve and a second output port connected to the transient pressure control valve. The signal pressure relay valve is switched by first and second relay pressures to selectively switch the destination of the signal pressure which is regulated by the linear solenoid valve. When the signal pressure is fed to the accumulator control valve, a modulator oil pressure is fed to the lockup control valve.
Abstract:
A shift control system for an automatic transmission, comprising a shift unit for selecting by manipulating a shift lever an automatic shift mode, in which a gear stage is determined on the basis of a running state of a vehicle, and a manual shift mode in which a gear state is determined from an output signal based on the manipulation. The shift unit has a drive range capable of setting a plurality of forward gear stages and a plurality of range positions arrayed and includes: a first shift path for guiding the shift lever into the range positions; a second shift path intersecting the first shift path for guiding the shift lever; two third shift paths formed at the two end portions of the second shift path, the third shift paths having at their individual end portions gear stage positions for indicating the forward gear stages in the automatic shift mode and for guiding the shift lever; and a manual shift instructor for outputting a signal instructing a gear stage corresponding to the gear stage position when the shift lever is moved to the gear stage position. The shift control system comprises a gear stage setter for setting the gear stage which is instructed by the output signal of the manual shift instructor.