Honda Giken Kogyo Kabushiki Kaisha

Takashi Iino

Eiichiro Kawahara

Yoshihiro Katagiri

Mikihiro Takano

Kazuya Maki

Akihito Okuda

Shigeru Morimoto

Kenichi Ikejiri

Noboru Yamamoto

Koji Yamaguchi

Yasuhiro Sawa

Tsuneaki Seino

Kenjiro Iwasawa

A hydraulic continuously variable transmission for use on a vehicle comprises a hydraulic variable pump, which is driven by an engine, and a hydraulic variable motor, which is driven by oil discharged from the hydraulic variable pump to drive wheels. In addition, this transmission includes shift position detecting means, which detects a shift position, and vehicle stop detecting means, which detects whether the vehicle is in halt. In this transmission, when the vehicle stop detecting means detects that the vehicle is in halt and the shift position detecting means detects that the shift position is in a forward or rearward drive position, the discharge capacity of the hydraulic variable motor is set to a maximum, and the discharge capacity of the hydraulic variable pump is controlled to a predetermined capacity (first predetermined capacity) in correspondence with the shift position. Thereby, the vehicle is prevented from relapse phenomenon, i.e., being dragged in the direction opposite to the direction set with the shift lever when the vehicle is stopped on a slope.

Hydraulic continuously variable transmission for use on vehicle

An axial piston pump provided with a pump shaft, a pump cylinder, pistons and a swashplate is stored in the inside of first and second case halves and connected to a valve plate by bolts. A tensile force is made to act on the bolts by transmitting a hydraulic pressure reaction received by the cylinder to the second case half through the valve plate and by transmitting a hydraulic pressure reaction received by the pistons to the first case half through the pump swashplate 32. The tensile force is canceled by generating a thrust force in the pump shaft 10 by meshing a helical gear 50 provided on the pump shaft 10 with a helical gear 49 supported on the valve plate 27, and transmitting this thrust force from the ball bearing 46 to the first case half 42. Thus, it is possible to reduce a tensile force which acts on the casing of an axial piston machine.

Axial piston machine

A hydraulic continuously variable transmission for use on a vehicle comprises a hydraulic closed circuit, first and second pressure controlling means, brake operation detecting means and deceleration detecting means. The hydraulic closed circuit includes a hydraulic pump, a hydraulic motor, a first oil passage connecting a port of the hydraulic pump with a port of the hydraulic motor and a second oil passage connecting another port of the hydraulic pump with another port of the hydraulic motor, and first and second pressure controlling means control the pressures of the first and second oil passages, respectively. If the deceleration of the vehicle is greater than a standard deceleration when the operation of the brake is detected, then the pressure of the first or second oil passage whose pressure is higher than that of the other is lowered to a predetermined low pressure that is higher than the pressure of either oil passage which is lower by either the first or second pressure controlling means. This predetermined low pressure is determined in reverse proportion to the engine rotational speed, thus preventing the engine from stalling when the wheels are locked up in an abrupt braking operation.

In a hydraulic/mechanical transmitting system, an input shaft of a power dividing device and a power collecting shaft coupled to a motor cylinder are disposed coaxially with each other. The power dividing device includes a first output member which is carried on an outer periphery of the power collecting shaft and operatively connected to a pump shaft parallel to the power collecting shaft, and a second output shaft which is fixedly mounted on the power collecting shaft. Thus, the number of the parallel shafts can be decreased to provide a simplified and compact structure.

Hydraulic/mechanical power transmitting system

A hydraulic/mechanical transmission device for providing variable speed change ratios with a decreased number of parallel shafts and a simplified and compact structure. A hydrostatic continuously variable transmission includes a hydraulic pump 24 with a pump cylinder block 28 and a hydraulic motor 25 with a motor cylinder block 34. An input shaft 9 and first and second output shafts 10.sub.1 and 10.sub.2 of a power dividing device 3 are coaxially disposed. The first output shaft 10.sub.1, is coaxially connected to the pump cylinder block 28 of the hydraulic pump 24. A power collecting shaft 17 is disposed parallel to the first and second output shafts 10.sub.1 and 10.sub.2 and coaxially connected to the motor cylinder block 34 of the hydraulic motor 25.

Hydraulic/mechanical transmission

A hydraulically operated continuously variable transmission associated with the engine of a motor vehicle has a clutch for controlling the transfer of power through the transmission and a hydraulic servo unit for selectively connecting and disconnecting the clutch. A clutch control device comprises a first discharge oil passage for discharging working oil from the hydraulic servo unit when the clutch is connected by the hydraulic servo unit to start the transfer of power, an orifice disposed in the first discharge oil passage and having a prescribed cross-sectional area, a second discharge oil passage for discharging the working oil from the first discharge oil passage, the second discharge oil passage communicating with the first discharge oil passage upstream of the orifice with respect to the direction in which the working oil flows through the first discharge oil passage, and a relief valve disposed in the second discharge oil passage and openable only when the pressure of the working oil in the second discharge passage is higher than the pressure of the working oil which is developed in the first discharge oil passage upstream of the orifice when the working oil is at a normal temperature. The degree to which the flow of the working oil is restricted by the orifice may be modified by an orifice charging valve depending on the magnitude of an indication of the throttle valve opening of the engine.

Clutch control device for transmission

A continuously variable automotive transmission continuously varies the speed ratio between input and output rotational speeds according to an indication of the driver's intention of acceleration or deceleration, an indication of an engine power output, and alternative selection of forward and neutral transmission positions, and also transmits the engine power output to wheels dependent on the operation of a clutch. The operating condition of the clutch is detected and fed back for the control of the transmission in order to perform speed changing operation of the transmission more quickly when the clutch is operated toward a shut-off position upon automobile deceleration than when ordinary speed changing operation is effected by the transmission.

Continuously variable automatic transmission

A hydraulically operated continuously variable transmission comprises a hydraulic pump and a hydraulic motor having a motor cylinder including an integral tubular member. A distribution disc is coupled to the motor cylinder at one end of the tubular portion and has oil passages communicating with the hydraulic pump and the hydraulic motor. A hollow fixed shaft is inserted in the tubular member, and a distribution ring is axially movably mounted on the fixed shaft and has an end face slidably held against the distribution disc. A mechanical seal assembly includes an annular rotatable seal member rotatably disposed in the tubular member, and an annular fixed seal member axially movably, but nonrotatably, mounted on the fixed shaft. A compression spring is disposed between the fixed seal member and the distribution ring and is resiliently extensible for applying a preload to abut an axial end face of the fixed seal member against an axial end face of the rotatable seal member and a preload to abut the end face of the distribution ring against the distribution disc.

Hydraulically operated continuously variable transmission

The transmission ratio of an automotive continuously variable transmission is controlled on the basis of the difference between a target rotational speed of the engine which is preset according to an indication of the driver's intention of acceleration or deceleration and a detected rotational speed of the engine. The gain of the rate of change of the transmission ratio is reduced as the detected rotational speed of the engine becomes higher, and the gain of the rate of change of the transmission ratio is increased as the detected rotational speed of the engine becomes lower. Alternatively, the gain of the rate of change of the transmission ratio is of a relatively small value when the detected rotational speed of the engine is equal to or higher than a preset speed, and the gain of the rate of change of the transmission ratio is of a relatively large value when the detected rotational speed of the engine is lower than said preset speed.

Method of controlling continuously variable automotive transmission

A hydraulically operated continuously variable automotive transmission includes a transmission ratio controlling member and a hydraulic actuator operatively coupled to the transmission ratio controlling member for continuously operating the transmission ratio controlling member to increase or reduce the transmission ratio of the continuously variable automotive transmission. A control valve is provided for applying a controlling hydraulic pressure to the hydraulic actuator dependent on the difference between a first control force commensurate with an indication of the automobile driver's intention of acceleration or deceleration and a second force commensurate with the engine rotational speed, in order to change the direction in which the hydraulic actuator is operated. The control valve includes, but is not limited to, a cylinder having two ports communicating with the hydraulic actuator, a port communicating with a source of hydraulic pressure, and a port communicating with an oil tank, a first spool slidably disposed in the cylinder and slidable dependent on the difference between the first and second control forces for selectively bringing the ports into and out of communication, a second spool slidably disposed in the first spool and movable in response to a control force commensurate with a control signal, and variable restrictions disposed between the first and second spools for varying the amount of controlling hydraulic pressure applied to the hydraulic actuator.

Apparatus for controlling continuously variable automotive transmission

A hydraulically operated continuously variable transmission for an automobile includes a hydraulic pump coupled to an input shaft and having an outlet port, a hydraulic motor coupled to an output shaft, at least one of the hydraulic pump and the hydraulic motor being of the variable-displacement type, a closed hydraulic circuit interconnecting the hydraulic pump and the hydraulic motor, and a device for selectively making and breaking the hydraulic circuit respectively by opening and closing the outlet port. The device comprises a valve body for closing the outlet port, a valve holder for driving the valve body to selectively open and close the outlet port, and a spring for normally urging the valve body in a direction to close the outlet port, the valve body and the valve holder being held in engagement with each other for relative displacement in directions to open and close the outlet port.

A hydraulically operated continuously variable transmission includes a hydraulic pump coupled to an input shaft, a variable-displacement hydraulic motor coupled to an output shaft, and a closed hydraulic circuit interconnecting the hydraulic pump and the hydraulic motor and including a passage connecting the inlet and outlet ports of the hydraulic pump. A servomotor makes and breaks the hydraulic circuit respectively by opening and closing the outlet port. A clutch valve continuously varies the cross-sectional area of the passage to change the amount of power transmitted between the hydraulic pump and the hydraulic motor. A control system independently controls the servomotor and the clutch valve, the control system being arranged to hold the servomotor in a position to open the outlet port when the clutch valve is opened beyond a prescribed degree. The hydraulic motor has motor plungers axially movable through a stroke which is variable by a tiltable motor swash plate which can be tilted by another servomotor. The servomotors include pilot valves which are operatively coupled to each other by a cam mechanism. The hydraulic circuit is kept broken when a motor vehicle incorporating the transmission runs at a prescribed speed or a higher speed and the angle of inclination of the motor swash plate is substantially minimal.

A continuously variable transmission for a motor vehicle has a closed hydraulic circuit disposed between a hydraulic pump and a hydraulic motor with the hydraulic motor being of the variable displacement type. The hydraulic pump is driven by the engine and the hydraulic motor is driven by the hydraulic pressure from the hydraulic pump for driving the road wheels. A pair of bypass passages are connected between the two oil passages of the closed hydraulic circuit between the hydraulic pump and hydraulic motor and a clutch valve is disposed in each bypass passage for adjusting the opening of that bypass passage. The opening of the bypass passages corresponding to the amount of operation of the clutch valves when the transmission receives driving forces from the road wheels during deceleration is controlled so as to be greater than the opening of the bypass passages when the transmission is driven by the engine to drive the road wheels.

Control device for a continuously variable transmission for motor

A hydraulic control device for a continuously variable vehicle transmission having a closed hydraulic circuit disposed between a hydraulic pump and a hydraulic motor, with at least one of said hydraulic pump and said hydraulic motor being of the variable displacement type. The hydraulic pump is driven by an engine and the hydraulic motor is connected to the road wheels and is driven by hydraulic pressure from the hydraulic pump. A pair or relief valves are disposed between the two oil passages of the closed hydraulic circuit extending between the hydraulic pump and the hydraulic motor, each of which are for relieving the pressure from one oil passage to the other oil passage. One relief valve relieves the pressure from the oil passage which has the higher pressure when the continuously variable transmission is driven by driving forces from the engine to drive the road wheels, and has a relief pressure setting controlled so as to increase as the speed of rotation of the engine increases. The other relief valve which relieves the pressure from the other oil passage which increases in pressure when said continuously variable transmission receives driving forces from the road wheels, has a relief pressure setting controlled so as to increase as the speed of the motor vehicle increases.

Hydraulic control device for a continuously variable transmission for

An actuator has a pilot valve incorporated in a piston thereof which is slidably disposed in a cylinder tube, the piston having first and second piston lands slidably disposed in first and second coaxial cylinder chambers. A spool valve body has first and second spool lands slidably disposed in an inner hole in the piston. When the spool valve body is moved in one direction, a first axial passage in the piston communicates with a pressure sink through a first return port which is opened by the first spool land, and a second axial passage in the piston communicates with a portion of the inner hole in front of the second spool land through a second supply port which is opened by the second spool land. When the spool valve body is moved in the opposite direction, the second axial passage communicates with the pressure sink through a second return passage which is opened by the second spool land, and the first axial passage communicates with a portion of the inner hole in front of the first spool land through a first supply port which is opened by the first spool land. The spool valve body is movable under a differential pressure between two inlet ports. The pilot valve cam amplify the operating force on the piston even if the difference between applied input oil pressure is small. In addition, the actuator is compact in size.

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Saitama, Japan

Takashi Iino