Abstract: The transmission is constructed with a first ring gear and a third ring gear that are firmly connected. A second ring gear and a third carrier are also firmly connected. A second sun gear and a third sun gear are also firmly connected. An input shaft is connectable to a first carrier via a first clutch. The input shaft is connectable to a first sun gear via a second clutch. A third clutch is disposed between the first carrier and a second ring gear. The first carrier is connectable to the second ring gear and the third carrier via the third clutch. A first brake is provided between the first sun gear and a transmission case. A second brake is provided between the transmission case and the first ring gear as well as the third ring gear. A third brake and a one-way clutch are provided in parallel between the first carrier and the transmission case. A fourth brake is provided between the transmission case and the second sun gear as well as the third sun gear.

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.

Abstract: When a current downshift is determined to be a multiple downshift, it is determined whether or not a torque down during a first downshift is in a condition of interfering with learning performed for stabilizing the downshift operation during a second downshift is executed. If the torque down during the first downshift is determined to be in the condition of interfering with the learning, the learning is prohibited.

Abstract: A vehicle planetary gear type multiple-step transmission wherein each of five rotary elements is constituted by sun gears, carriers and ring gears of three planetary gear sets, and speeds of the rotary elements are represented by respective straight lines in a collinear chart, and the first, second and third rotary elements are made stationary by respective first, second and third brakes, and the fifth, third and first rotary elements are connected to an input shaft by respective first, second and third clutches, while the third rotary element is brought to a disconnected state by fourth clutch, and the fourth rotary element is connected to an output rotary member.

Abstract: A condition for driving an electric oil pump is set. A turbine speed or an input speed of an automatic transmission is measured. A correction amount for a hydraulic pressure is calculated on the basis of the turbine speed obtained by reference to a relation between the turbine speed and hydraulic pressure, and a correction amount for a drive duty ratio of the electric oil pump which is required for generation of the corrected hydraulic pressure is calculated. The procedure is resumed after the procedure has been performed. The condition for driving the electric oil pump is updated on the basis of the correction amount for the drive duty ratio calculated.

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 shift device, which sends a command signal to an electric actuator for shifting a plurality of gear ranges of a transmission of a vehicle by the electric actuator. The gear ranges include a plurality of drive ranges and a parking range. A shift lever is arranged to move between a neutral position and a plurality of manipulation positions located about the neutral position. A restoration mechanism restores the shift lever to the neutral position. A first sensor electrically detects a manipulation performed to select one of the drive ranges. A second sensor electrically detects a manipulation performed to select the parking range. The first sensor detects toward which of the manipulation positions the shift lever is manipulated.

Abstract: An automatic start controlling apparatus for automatically starting an internal combustion engine. A transmission is coupled to the engine. The transmission has a clutch, which is actuated by an oil pump other than the engine when the engine stops. The transmission has an input shaft and an output shaft. The input shaft is connected to the engine. The automatic start controlling apparatus has a controller. When the engine is automatically started, the controller detects whether the clutch is completely engaged. When the controller judges that the clutch is partially engaged, the controller reduces the output torque of the engine or limits an increase of the output torque.

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: An automatic start controlling apparatus for automatically starting an internal combustion engine. A transmission is coupled to the engine. The transmission has a clutch, which is actuated by an oil pump other than the engine when the engine stops. The transmission has an input shaft and an output shaft. The input shaft is connected to the engine. The automatic start controlling apparatus has a controller. When the engine is automatically started, the controller detects whether the clutch is completely engaged. When the controller judges that the clutch is partially engaged, the controller reduces the output torque of the engine or limits an increase of the output torque.

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.

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 parking control mechanism to prevent generation of noise and shock when a parking range is released after a vehicle has been parked so that a driver does not feel uncomfortable. A parking apparatus of an automatic transmission has a parking gear; a parking pole swingably disposed and provided with a claw arranged to selectively be engaged with a tooth space of the parking gear; an engagement inhibition device movably disposed and arranged to be moved to an inhibition position for inhibiting engagement between the claw and the tooth space and to an inhibition release position for releasing the inhibition of the engagement; and an engagement inhibition release device for moving the engagement inhibition device to the inhibition release position in synchronization with the rotation of the parking gear. After a residual torque existing between the parking gear and drive wheels has been released, the claw and the tooth space are engaged with each other.

Abstract: An automatic transmission including at least one rotary member; a rotary member enclosure enclosing the rotary member; and an oil reservoir arranged below the rotary member enclosure for collecting and reserving the oil. An oil separator is located facing the outer circumference of the rotary member for separating the oil adhering to the rotary member. Because the amount of oil left on the surface of the rotary member is reduced, the amount of oil recovered in the oil reservoir is accordingly increased and the level of the oil surface in the oil reservoir is prevented from falling.

Abstract: A shift control system of an automatic transmission sets a predetermined gear stage by applying a first frictional engagement element and releasing a second frictional engagement element. A pressure regulating mechanism regulates an oil pressure to be fed to or drained from the first frictional engagement element. A failure detector detects a failure of an apparatus to participate in the regulation and control of the oil pressure which is to be fed to or drained from at least one of the first and second frictional engagement elements. A gear stage inhibitor inhibits the setting of the predetermined gear stage if the failure is detected by the failure detector.

Abstract: An oil seal member is compressed between a connecting pipe for supplying oil to an oil chamber of a hydraulic servo and the cylinder drum of the hydraulic servo. The cylinder drum has an interior oil chamber and turns through a predetermined angle upon operation of a frictional engagement element by the hydraulic servo. The end of the seal member pressed against the cylindrical drum surrounds an oil hole 73 formed in the cylindrical drum, and oil pressure is supplied to the oil chamber through an oil passage in which the seal member is mounted and through the oil hole. A recess is formed in the outer surface of the cylindrical drum around the oil hole and the end of the seal member is received in the recess. When the cylindrical member turns within the predetermined angular range, the end of the seal member is protected by the recess. As a result, the end of the seal member is not damaged and the integrity of the seal is protected.

Abstract: A control system for an automatic transmission, in which a first frictional engagement element and a second frictional engagement element are released according to a shift from a running range to a non-running range. The shift from the running range to the non-running range is detected, and the reduction in the oil pressure of the second frictional engagement element is controlled on the basis of the reduction in the oil pressure of the first frictional engagement element when the shift from the running range to the non-running range is detected.

Abstract: An automatic transmission control system is equipped with a pressure modulating valve for regulating the engaging pressure to be supplied to frictional engagement elements for setting respective gear stages of the automatic transmission, a signal pressure output valve for providing signal pressure, and a switching valve.

Abstract: An oil temperature responsive hydraulic control system for an automatic transmission includes a hydraulic servo for applying/releasing a frictional engagement element; a pressure regulator valve for regulating oil pressure fed to the hydraulic servo; and a signal pressure oil passage for applying a pressure regulating signal pressure to the pressure regulator valve. A control valve is arranged in the signal pressure oil passage for changing the effective diameter of the signal pressure oil passage responsive to change in oil temperature.

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.