Toyota Jidosha Kabushiki Kaisha

Nobuyuki Kato

Hiroshi Itoh

Kunio Morisawa

Yuji Hattori

Masami Sugaya

Mitsuru Takada

Yoshinobu Soga

Ryoji Habuchi

Katsumi Kouno

Mitsuhiko Okada

Michitaka Kakamu

Seitoku Kubo

Takashi Hayashi

Shinya Nakamura

Koujiro Kuramochi

Hideki Miyata

Tokuyuki Takahashi

Tetsuya Abe

Hiroyasu Honda

Yasuo Houjo

A plurality of convex portions that protrude radially outward from a plurality of positions separated in the circumferential direction are provided on the outer peripheral surface of a driven gear. Each convex portion has, in the circumferential direction of the driven gear, a rising surface that rises from a minimum diameter position to a maximum diameter position in the direction opposite the rotational direction of the driven gear, and a falling surface that falls from that maximum diameter position to a minimum diameter position that is adjacent to and in back of that maximum diameter position with respect to the rotational direction of the driven gear. The circumferential length of the falling surface is greater than the circumferential length of the rising surface.

Oil pump for a vehicle

A hydraulic control apparatus for controlling a vehicle power transmitting system including a belt-and-pulley type continuously variable transmission and a torque converter provided with a lock-up clutch. The transmission includes a pair of hydraulic actuators one of which receives a belt tensioning pressure for controlling a tension of a transmission belt. The hydraulic control apparatus includes a lock-up clutch control valve which is selectively placed in an engaging and a releasing position for engaging and releasing the lock-up clutch, respectively, a slip control valve for controlling an amount of slipping of the lock-up clutch until the clutch is fully engaged, a pressure control device for raising the belt tensioning pressure so as to increase the tension of the transmission belt; and a pilot-pressure generating device for applying a pilot pressure simultaneously to the slip control valve and the pressure control means, so that the belt tensioning pressure is raised while the slip control valve controls the amount of slipping of the lock-up clutch.

Hydraulic control apparatus for power transmitting system including

A hydraulic control apparatus for a power transmitting system including a continuously variable transmission, a reversing device, and an auxiliary transmission, which apparatus includes: a solenoid valve for generating a pilot pressure for selectively placing the auxiliary transmission in high- and low-gear positions; high-gear and low-gear control valves normally operable based on the pilot pressure, to control high- and low-gear coupling devices of the auxiliary transmission to establish the high- and low-gear positions. The low-gear control valve is operated to engage the low-gear coupling device, when the low-gear control valve receives a pressure to be applied to the reversing device for forward run of the vehicle. The high-gear control valve may be operated to release the high-gear coupling device, when a thrust based on a pressure applied to the low-gear coupling device exceeds a predetermined value. The hydraulic control apparatus may further include a device for increasing a torque capacity of the high-gear coupling device during an engaging action thereof when a shift lever is operated to a reverse-drive position for reverse run of the vehicle.

Hydraulic control apparatus for continuously variable power transmitting

A hydraulic control apparatus for controlling a belt-and-pulley type continuously variable transmission of a motor vehicle having an engine, which transmission includes a pair of hydraulic actuators one of which receives a belt tensioning pressure for controlling a tension of a transmission belt. The hydraulic control apparatus includes an engine-output detecting valve for generating an engine output pressure indicative of a currently required output of the engine, a solenoid-operated valve for regulating a modified engine output pressure based on the engine output pressure generated by the engine-output detecting valve, and a pressure regulating valve for regulating the belt tensioning pressure based on at least the modified output pressure. The modified engine output pressure is obtained so that the belt tensioning pressure is controlled to an optimum level.

Hydraulic control apparatus for belt-and-pulley type continuously

A hydraulic control apparatus for controlling a continuously variable transmission of a motor vehicle, which transmission includes a first and a second shaft, a pair of variable-diameter pulleys provided on the first and second shafts, respectively, a transmission belt connecting the pulleys, and a pair of hydraulic actuators one of which receives a belt tensioning pressure for controlling a tension of the belt. The hydraulic control apparatus includes a reversal detecting device for determining whether a rotating direction of the pulleys has been reversed or not, and a pressure increasing device for temporarily increasing the belt tensioning pressure when the reversal detecting device detects reversal of the rotating direction of the pulleys.

A hydraulic control apparatus for a vehicle continuously variable transmission including a pressure regulating valve having a valve spool which operates depending upon a determined current speed ratio of the transmission and a currently detected required output of the vehicle engine, to generate a controlled belt tensioning pressure for controlling the tension of a transmission belt at a required minimum level. The apparatus further includes a device responsive to an electric signal, for generating a pilot pressure to be applied to the valve, and an electronic control device for calculating a basic output pressure of the valve, based on the current speed ratio and the currently required output, according to a stored predetermined relationship among these two parameters and the basic output pressure, to determine the electric signal so that the belt tensioning pressure coincides with the optimum value.

A hydraulic control apparatus for a vehicle power transmission for transmitting power from an engine to a drive wheel a reversing mechanism having a reverse position established by a hydraulic actuator. The apparatus includes a reverse inhibit valve disposed in a hydraulic line leading to the hydraulic actuator and having a reverse inhibit position for inhibiting the mechanism from being placed in the reverse position and a non-inhibit position for permitting the mechanism to be placed in the reverse position. The apparatus uses a first and a second pilot pressure generating device for producing a first and a second pilot pressure, respectively. A relay valve is provided for producing a first hydraulic signal for establishing the reverse inhibit position of the reverse inhibit valve, based on one of combinations of operating states of the two pilot pressure generating devices, and a second hydraulic signal for establishing the non-inhibit position, based on the other combinations.

Hydraulic control apparatus for vehicle transmission system,

An apparatus for controlling a hydraulic clutch, including a two-position clutch control valve, a two-position rapid clutch release valve, and a first fluid passage system for releasing the clutch, a second fluid passage system for engaging the clutch, and a third fluid passage system for releasing the clutch. These three passage systems for feeding and discharging a fluid into and from the clutch are selected by respective three combinations of the operating positions of the two valves. Normally, a predetermined one of the first and third passage systems is selected for releasing the clutch, and the other of these two systems is selected in the event of a trouble with the valves.

Apparatus for controlling hydraulically operated clutch in vehicle

An apparatus for controlling a vehicle continuously variable transmission, including a directional control valve having a first spool movable between a shift-down and a shift-up position, a flow control valve including a second spool movable between a flow-restricting and a non-restricting position, and a first and a second solenoid-operated valve for applying an actuating pressure to the first and second spools. The directional and flow control valves and the solenoid-operated valves are adapted such that the first and second spools are moved toward the shift-up and flow restricting positions, respectively, when the actuating pressure is not applied to the spools, or when solenoid coils of the two solenoid-operated valves are both off. The directional control valve may have a shift-down chamber for receiving a pilot pressure to move the first spool to the shift-down position when a failure of one of the solenoid coils exists while the vehicle speed is lower than a predetermined limit.

The hydraulic pressure for operating the two wheel drive/four wheel drive switchover clutch in the part-time type four wheel drive device or the central differential lock-up clutch in the full-time type four wheel drive device is produced by a combination of a pressure regulation valve and two switchover valves to be selectable among several substantially different pressure levels so that the four wheel drive device can be quickly switched over between the complete four wheel operation and the complete two wheel operation, including one or more intermediate half clutched incomplete four wheel operation.

Hydraulic pressure control device for clutch for controlling drive

A hydraulically actuated clutch is included in a four wheel drive device included in a vehicle power train, and is utilized for torque distribution between the front vehicle wheels and the rear vehicle wheels. A hydraulic control device for this torque distribution clutch includes a device for producing a control hydraulic fluid pressure for this clutch according to an oscillatory method such as a duty factor method or a dither method, an output conduit for conducting this control hydraulic fluid pressure out from this device for producing it, and a device for smoothing hydraulic pressure fluctuations in this output conduit. Accordingly, when wobbling or relatively small fluctuations tend to be induced in this control hydraulic fluid pressure in this output conduit, as may typically be caused by the oscillatory nature of the process for producing this control hydraulic fluid pressure, these wobbles and fluctuations are smoothed out by the smoothing device, thus making for smoother control of the control pressure for the clutch. Thereby, the engagement pressure of the clutch and hence the torque transmission capacity thereof are properly stabilized, and the torque distribution between the front wheels of the vehicle and the rear wheels of the vehicle is prevented from fluctuating, accordingly enhancing the drivability and the operational feeling of the vehicle, as well as decreasing tire wear and increasing roadability. This device for smoothing hydraulic pressure fluctuations may be a hydraulic accumulator; and the device for producing a control hydraulic fluid pressure may be an electromagnetic valve.

Hydraulic control device for 4WD torque distribution clutch providing

A method and apparatus for controlling a power transmitting system for an automotive vehicle, including a continuously variable transmission (CVT) and an auxiliary transmission which is connected to the CVT and which is automatically shifted from one of two or more forward drive positions to the other depending upon operating conditions of the vehicle. To control the speed ratio of the CVT, a target speed of the input shaft of the CVT is determined according to one of different relationships between the target speed and at least one variable such as a currently required output of the engine. The relationships are stored in memory, corresponding to the forward drive positions of the auxiliary transmission. The appropriate relationship is selected depending upon the forward drive position in which the auxiliary transmission is currently placed while the transmission shift lever is in an auto-shift or engine-brake position. The automatic shift-down and shift-up operations of the auxiliary transmission may be effected according to predetermined shift patterns corresponding to drivability modes of the vehicle selected on a suitable drivability selector device.

Method and apparatus for controlling power transmitting system for

A belt type continuously variable transmission system which includes: a fluid coupling device for transmitting an output from an engine by use of fluid; a belt type continuously variable transmission device for transmitting an output from the fluid coupling device at a continuously variable transmission gear ratio through a belt; an auxiliary transmission device having a function of shifting an output from the belt type continuously variable transmission device in accordance with the forward reverse running conditions; a reduction gear device for reducing an output from the auxiliary transmission device; and an oil pump device for feeding the hydraulic pressures to various hydraulic pressure components such as a valve body and the like wherein the various devices are connected to one another while preventing the various devices from interfering with one another, whereby proper functions of the various devices are satisfactorily performed and the transmission system as a whole can be made simplified in construction and be compact in size.

Belt type continuously variable transmission system

A hydraulic control apparatus for controlling a hydraulically-operated power transmitting system for an automotive vehicle, the transmitting system having a continuously variable transmission and an auxiliary transmission coupled to an output side of the continuously variable transmission. The controlling apparatus comprises a first pressure generator for generating a first line pressure used to operate the continuously variable transmission, and a second pressure generator for generating a second line pressure used to operate a frictional coupling assembly incorporated in the auxiliary transmission.

Hydraulic control apparatus for hydraulically-operated power

A hydraulic control apparatus for controlling a hydraulically hydraulically-operated power transmitting system for an automotive vehicle, the transmitting system having a continuously variable transmission and an auxiliary transmission coupled to an output side of the continuously variable transmission. The controlling apparatus comprises a first pressure generator for generating a first line pressure used to operate the continuously variable transmission, and a second pressure generator for generating a second line pressure used to operate a frictional coupling assembly incorporated in the auxiliary transmission.

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Toyota, Japan

Nobuyuki Kato