Abstract: A working fluid pressure control system for an automatic power transmission includes a pre-charge pressure regulating mechanism for temporarily elevating a working fluid pressure abruptly and subsequently drop the working fluid pressure for generating a pre-charging constant pressure for a start-up friction element, and a detecting portion for detecting an operational range before selection of neutral range. When selection is made from neutral range to a traveling range, and the traveling range is different from the operational range before selection of the neutral range, the pre-charge pressure regulating mechanism is actuated when judgement is made that the start-up friction element engaged in the operational range before selection of neutral range is released, thus selection being performed within a short period without accompanying with a shock.

Abstract: An engine output control apparatus for an internal combustion engine includes a drive force transferring section interconnected with a crankshaft of the engine. The output of the engine is controlled at a desired value by an output control section. A transferred torque through the drive force transferring section is estimated by a torque estimating section. A torque suppressing section lowers the output of the engine so as to keep the estimated torque within a predetermined range by sending a signal to the output control section. A shift detecting section outputs a signal to a time delaying section when it detects a shifting from an output-control required shift position to a normal shift position. The time delay section outputs the estimated torque value to the torque suppressing section upon delaying for a predetermined delay time corresponding to a shifting time when the time delay section is operated by the shift detecting section.

Abstract: Along a peripheral wall surface of a pump housing at a closure portion where a working fluid in a volume chamber defined by engagement of an inner rotor and an outer rotor, is enclosed, a liquid pressure is relieved by the liquid pressure relieving groove for relieving a liquid pressure of the working fluid from the volume chamber to a sliding gap along an outer peripheral surface of the outer rotor.

Abstract: A hydraulic control device for an automatic transmission includes a reverse inhibit valve for inhibiting a reverse gear position to be established when the reverse range is selected by mistake. This reverse inhibit valve is placed in a selected one of a first state in which a first port communicates with a third port, and a second state in which a second port communicates with the third port, depending upon whether a solenoid pressure is applied to one end of a spool of the valve. If the reverse range is selected during forward running of a vehicle, the reverse inhibit valve is placed in the first state in which the first port communicates with the third port, so that an oil pressure of a friction element is drained through the first port.

Abstract: A cooling structure of an automatic transmission is provided which is capable of reducing the number of assembly parts and obtaining a high cooling efficiency by placing two heat sources away from each other. A high clutch device (15) is disposed between a front planetary gear device (13) and a rear planetary gear device (14) which is parallelly disposed in the direction in which an input shaft (4) in the front planetary gear device (13) extends. The high clutch device (15) includes a cylindrical clutch drum (15a), a clutch piston (15b) which slides in the direction of the input shaft (4) inside of the clutch drum portion (15a) and forms a piston-operating oil hydraulic chamber (20) in combination with the clutch drum portion (15a), and a plurality of clutch plates (15c) which are pressed by the clutch piston (15b) and laminated in the direction in which the input shaft (4) extends. The clutch drum (15a) is formed intetrally with a planetary carrier (18).

Abstract: A planet carrier of an automotive automatic transmission includes an annular main body portion disposed around a pinion shaft between the carrier body and the pinion gear. A washer formed of a porous material such that lubricating fluid can flow therethrough to both sides of the washer is disposed around the pinion shaft. Further, a boss portion may be formed at the inner periphery of the washer opening, which portion is inserted between the surface of the pinion shaft and an inner circumference of the pinion gear. A fluid passage is defined according to installation of the washer, between the edge of the washer and the bearings of the pinion gear such that lubricating fluid is retained therein, which fluid flows around the pinion shaft.

Abstract: In a hydraulic control device for an automatic transmission for obtaining the optimum shift-down timing by regulating an accumulator back pressure for an engaging element to be engaged in low-speed gear positions, switch control means is provided for communicating an output oil path communicating with an accumulator back pressure chamber, with a selected one of an accumulator control pressure oil path and a drain oil path. The switch control means maintains communication between the output oil path and the accumulator control pressure oil path due to the output feed-back pressure in the N-speed gear position, and brings the output oil path into communication with the drain oil path, using the N+1 pressure as the operating signal pressure, upon shifting-up from the N-speed to N+1-speed gear position.

Abstract: A clutch device for automatic transmission comprises a rotatable high clutch drum, a ring-like piston movably fit in the high clutch drum in the axial direction, and a drift-on ball which is inserted in a staged through-hole penetrating the piston in its axial direction and is able to interrupt and communicate with the through-hole by movements thereof in the axial direction. An oil supplying and discharging port which is able to supply oil into an oil chamber partitioned by the high clutch drum and piston is formed at inner circumference of the high clutch drum. A groove which causes the oil supplying and discharging port of the high clutch drum and the through-hole to communicate with each other through a space between each inner circumference of the piston and the high clutch drum is formed at the oil chamber side of the piston.

Abstract: A slip control system for an automotive vehicle includes an automatic power transmission, a torque converter, a lock-up control device for controlling operation of the lock-up device depending upon an input from a traveling state detection device which detects traveling condition including driving operation, an acceleration slip detection device provided as a part of the traveling state detection device for detecting acceleration slip of the driving wheels, a torque reduction device for reducing a torque to be delivered to the drive wheels, an acceleration slip control device for operating the torque reduction device for performing acceleration slip suppressing control when the acceleration slip detecting device detects acceleration slip, and a holding device for inhibiting switching of operational state of the lock-up device by the lock-up control device while the acceleration slip control device is in operative state for performing acceleration slip suppressing control, to maintain the torque converter in t

Abstract: An automatic transmission control unit switches on and off operations for a plurality of solenoids in response to combinations of throttle openings estimated on the basis of an output of a throttle sensor and vehicle speeds estimated on the basis of an output of a vehicle speed sensor to set a proper speed change gear. The automatic control unit sets second gear when a vehicle is stopped to suppress creep during the stoppage of the vehicle, and starts the vehicle with the second gear as it is when the changing rate of the throttle opening is small. When the changing rate of the throttle opening exceeds a predetermined rate in an acceleration state, it is determined that an operator desires powerful acceleration and hence the operation is shifted to first gear. In contrast, when the operator requires a slow start, a second gear start is automatically selected without permitting down-shift to the first gear every time the vehicle is started.

Abstract: A method for producing a washer having a boss comprises the following steps in the sequence set forth: (a) sprinkling powder of a bearing alloy onto a backing metal made of an iron-based alloy to form a composite material; (b) sintering the composite material to obtain a bimetal material so as to accomplish a primary sintering; (c) fabricating the bimetal material into a shape of the washer having the boss; and (d) simultaneously accomplishing a secondary sintering and carburizing of the washer having the boss. By virtue of simultaneously conducting the secondary sintering and the carburizing for the washer, the number of steps in producing method (particularly, during a heat treatment) is reduced thereby improving the productivity of the washer having the boss while reducing thermal energy required for the heat treatment.

Abstract: A casing body of a transmission casing has an oil pan mounting flange including an oil pan joint surface for joining an end surface of the oil pan, and a housing mounting flange including a housing joint surface for joining an end surface of a housing. The oil pan mounting flange and the housing mounting flange are provided substantially perpendicularly to each other. A reinforcing rib is formed parallel to the oil pan joint surface to reinforce the casing body. A pocket part is formed on the back surface of the reinforcing rib opposite to the direction of the oil pan joint surface, and a processing/assembling reference hole is formed in the reinforcing rib at a location of the rib where the pocket part is formed. As the reference hole is obtained without protruding the flanges, a greater degree of design freedom is provided and material costs are reduced. Further, if the flange is clamped, a claiming force is not exerted on the reference hole, thereby preventing deformation or displacement of the hole.

Abstract: According to the clutching device of the present invention, a flexible member, which uniformly forces a plurality of friction plates almost in the circumferential direction, is inserted between edge faces, of fixed friction plates, to which no load is applied at the time of engagement, and a spline face that is opposite to the edge faces. The insertion position is selected at such a location where the rotational direction of a rotary body is diagonally upward and toward the center. Since a load on and a degree of distortion of the flexible member are small, the flexible member can be compactly made and can have a simple design, and the mounting structure on the spline side is also simpler.The clutching device with this structure effectively prevents the vibration of friction plates, requires only a small number of components. And additional components are easily installed and removed.

Abstract: A transmission gear support arrangement supports an output gear associated with a planetary gear arrangement receiving torque from an input shaft. The output gear drives and engaged gear mounted on a second shaft mounted in parallel to the input shaft. The output gear is supported on a cylindrical boss portion disposed coaxially around the input shaft, projected from an internal wall of the transmission casing. A bearing is mounted on the outer circumference of the boss portion and has an inner race between the inner side of the bearing and the outer surface of the boss portion and an outer race between the outer side of the bearing and an inner circumference of an output gear which is mounted around the boss portion. In this way the output gear may be provided closely adjacent the planetary gear and the length of the input shaft and the second shaft may be kept substantially short.

Abstract: In response to a signal indicating the present throttle valve opening degree detected by a throttle valve sensor and a signal indicating the present vehicle speed detected by a vehicle speed sensor, a lock-up controller determines whether a lock-up clutch should be brought into the operatively connected state or it should be released from the operatively connected state, and on completion of the foregoing determination, the controller outputs a certain signal to a solenoid valve. In the case that the lock-up clutch has been released, this state is maintained. On the contrary, in the case that the lock-up clutch has been in the operatively connected state, the controller determines whether maintains this state or selects a lock-up clutch releasing pattern depending on the present throttle valve opening degree.

Abstract: A clutch assembly structure for a multiple disk clutch is provided which includes a first clutch assembly and a second clutch assembly which are coaxially arranged in parallel with each other, such that the first clutch assembly is located radially outwardly of the second clutch assembly. The second clutch assembly includes a second drum, a second piston slidably received in the second drum, and a second oil chamber formed between the second drum and the second piston. A canceling oil chamber for canceling the centrifugal oil pressure in the second oil chamber is formed within the second piston. In the canceling oil chamber is provided a canceling piston for canceling the centrifugal oil pressure in the second oil chamber. A second return spring consisting of a wave spring is provided between the second piston and the canceling piston. The axial length of the clutch assembly is reduced, thereby rendering the whole multiple disk clutch small-sized.

Abstract: An engagement structure for coupling a connecting shell to a clutch drum of an automatic transmission includes protrusions on the connecting shell that engage with grooves of the clutch drum. Edges of the grooves and edges of the protrusions are rendered by plastic deformation upon press-stamping to be formed thicker than other portions of the connecting shell and clutch drum. The resulting increased area of abutment between the connecting shell and the clutch drum transmits the same torque with less surface pressure, such that reduction in weight and size of the overall transmission components can be realized.

Abstract: A gear shift control apparatus for use with an automatic transmission including a friction element operable on a hydraulic pressure applied thereto in an engaged and disengaged state. A gear ratio obtained in the automatic transmission is calculated based on transmission input and output shaft speeds. A reference gear ratio is set based on at least one of the transmission input and output shaft speeds. The hydraulic pressure is changed from a first level to a second level to change the friction element from the disengaged state to the engaged state so as to produce a change from a higher gear to a lower gear when the gear ratio reaches the reference gear ratio. The reference gear ratio increases as at least one of the transmission input and output shaft speeds increases. Alternatively, the reference gear ratio may be set at a smaller value as the rate of change of the gear ratio increases.

Abstract: In response to a signal indicating the present throttle valve opening degree detected by a throttle valve sensor and a signal indicating the present vehicle speed detected by a vehicle speed sensor, a lock-up controller determines whether a lock-up clutch should be brought into the operatively connected state or it should be released from the operatively connected state, and on completion of the foregoing determination, the controller outputs a certain signal to a solenoid valve. In the case that the lock-up clutch has been released, this state is maintained. On the contrary, in the case that the lock-up clutch has been in the operatively connected state, the controller determines whether maintains this state or selects a lock-up clutch releasing pattern depending on the present throttle valve opening degree.

Abstract: A gear shift control apparatus for use in an automatic transmission having a friction element operable on a hydraulic pressure applied thereto in an engaged and disengaged state. A shift change control is performed to change the hydraulic pressure in a manner to produce a shift change according to a predetermined shift schedule based on transmission input and output shaft speeds and engine load. A section is provided for calculating the gear ratio obtained in the automatic transmission based on the transmission input and output shaft speeds. When a change is effected to one of highest and lowest gears or when a change is effected from one of the highest and lowest gears, a transient hydraulic pressure control of changing the hydraulic pressure from the first level to the second level is performed to change the friction element state so as to effect a shift change when the calculated gear ratio reaches a reference gear ratio.