Honda Giken Kogyo Kabushiki Kaisha

Akihito Okuda

Yoshihiro Katagiri

Shigeru Morimoto

Takashi Iino

Yoshihiro Kanamaru

Koichi Fushimi

Hirohisa Ogawa

Toshiaki Tane

Eiichiro Kawahara

Kenichi Ikejiri

Mikihiro Takano

Michio Suzuki

Hiroshi Terayama

Hiromi Aoki

The present invention provides a hydraulic controller for a variable capacity hydraulic transmission. This hydraulic controller reduces the load of the engine to improve fuel efficiency while maintaining a hydraulic pressure which is necessary for the control of the skew angles of the swash plates of the variable capacity type hydraulic pump and hydraulic motor that are incorporated in the transmission. The hydraulic controller adjusts the hydraulic pressure supplied to the servo cylinders and which are to tilt the pump swash plate and the motor swash plate , to a minimum necessary pressure on the basis of the pressure Ph of the oil passage which is at the higher pressure in the hydraulic closed circuit . The hydraulic controller adjusts the hydraulic pressure also on the basis of the types of the valve plates of the hydraulic pump and the hydraulic motor , the skew angles of the swash plates, the rotational speed Np of the hydraulic pump and the rotational speed Nm of the hydraulic motor, and the operational condition of the transmission.

Hydraulic controller for variable capacity hydraulic transmission

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

A relief pressure controlling device comprises a driving side relief pressure controlling valve, a capacity detector which detects the capacity of a hydraulic pump, and an engine throttle opening detector. When the hydraulic pump and the hydraulic motor which are connected by a first oil passage and a second oil passage constituting a hydraulic closed circuit are driven by an engine, the relief pressure controlling valve controls the relief pressure of the oil passage on the driving side that is either the first oil passage or the second oil passage whose pressure becomes higher than the other, to a target relief pressure. The target relief pressure is determined in correspondence with the engine output and corrected on the basis of the pump efficiency which is predetermined in relation to the capacity of the hydraulic pump and to the throttle opening, and this corrected target relief pressure is set as a driving side target relief pressure. The driving side relief pressure controlling valve performs a relief pressure control so that the relief pressure of the driving side oil passage will become the driving side target relief pressure, which is set in correspondence with the capacity of the hydraulic pump and the engine throttle opening.

Relief pressure controlling device used in vehicular hydraulic

A power of an input shaft driven by an engine is divided by a power dividing device and transmitted to first and second output shafts and a hydraulic pump of a hydrostatic continuously variable transmission is driven by the first output shaft, whereas a hydraulic motor is driven by the second output shaft through a mechanical transmission device and also by the hydraulic pump. A main oil pump is provided at the input shaft which rotates at the same speed as an engine speed, and a subsidiary oil pump is provided at the first output shaft which decreases rotational speed thereof to zero with an increase in the engine rotational speed. In a low rotational speed region of the engine, oil is supplied by both the main oil pump and the subsidiary oil pump, whereas in a high rotational speed region of the engine, oil is supplied by only the main oil pump. With this construction, it is possible to prevent a waste of energy required to drive the oil pump in the high rotational speed region of the engine while ensuring the quantity of oil supply from the oil pump in the low rotational speed region of the engine.

Hydraulic and mechanical transmission apparatus

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 swash-plate plunger-type hydraulic device has a cylinder block with a plurality of plungers slidably fitted in cylinder bores, a swash plate confronting one end of the cylinder block, and a distribution valve plate slidably held against the other end of the cylinder block. The cylinder block has an odd number of circularly arrayed connecting ports communicating with the cylinder bores and opening at the other end thereof. The distribution valve plate has inlet and outlet ports. The cylinder block is rotatable through an angular displacement .theta.1 in which the hydraulic pressure in one connecting port between the inlet and outlet ports increases from a lower pressure to a higher pressure, through an angular displacement .theta.2 in which the hydraulic pressure in one connecting port between the inlet and output ports decreases from the higher pressure to the lower pressure, and through an angular displacement .theta.3 from a position where the hydraulic pressure starts to increase to a position where the hydraulic pressure starts to decrease. The inlet and outlet ports are defined such that the angular displacements .theta.1, .theta.2, .theta.3 are expressed by:

High-efficiency reduced-noise swash-plate-type hydraulic device

A swash-plate plunger-type hydraulic device has a cylinder block with a plurality of plungers slidably fitted in cylinder bores, a swash plate confronting one end of the cylinder block, and a distribution valve plate slidably held against the other end of the cylinder block. The cylinder block has an even number of circularly arrayed connecting ports communicating with the cylinder bores and opening at the other end thereof. The distribution valve plate has inlet and outlet ports. The cylinder block is rotatable through an angular displacement .theta.1 in which the hydraulic pressure in one connecting port between the inlet and outlet ports increases from a lower pressure to a higher pressure, through an angular displacement .theta.2 in which the hydraulic pressure in one connecting port between the inlet and output ports decreases from the higher pressure to the lower pressure, and through an angular displacement .theta.3 from a position where the hydraulic pressure starts to increase to a position where the hydraulic pressure starts to decrease. The inlet and outlet ports are defined such that the angular displacements .theta.1, .theta.2, .theta.3 are expressed by:

High efficiency reduced-noise swash-plate-type hydraulic device

A hydraulically operated continuously variable transmission comprising a hydraulic motor of the variable displacement type having a motor cylinder coupled to an output shaft and including motor plungers slidably disposed respectively in a number of cylinder holes defined in an annular pattern surrounding the axis of rotation of the motor cylinder, and a hydraulic pump coupled to an input shaft. The hydraulic motor and hydraulic pump are interconnected by a closed hydraulic circuit in which the flow of working oil is controlled by a distribution ring which is relatively rotatably and slidably held against an end surface of the motor cylinder for successively switching the introduction of working oil into the cylinder bores and the discharge of working oil from the cylinder bores in response to rotation of the motor cylinder. The distribution ring has an asymmetrical hydraulic pressure bearing area in order to minimize forces tending to tilt the distribution ring relative to the motor cylinder end surface.

Distribution ring in hydraulically operated continuously variable

A hydraulically operated continuously variable transmission comprises a hydraulic motor coupled to an output shaft, a hydraulic pump coupled an input shaft, and a closed hydraulic circuit interconnecting the hydraulic motor and the hydraulic pump. The hydraulic motor has an annular array of slidable motor plungers disposed around an axis of rotation thereof and slidably disposed in respective cylinder holes defined in the motor cylinder. The hydraulic motor also has a distribution ring supported on the fixed shaft and rotatable relatively to and slidable against an end face of the motor cylinder for introducing high-pressure oil successively into the cylinder holes and discharging oil successively from the cylinder holes in response to rotation of the motor cylinder. The transmission also includes a hydraulic pump coupled to an input shaft, at least one of the hydraulic pump and the hydraulic motor being of the variable-displacement type, and a closed hydraulic circuit interconnecting the hydraulic pump and the hydraulic motor. The distribution ring is held in engagement with the fixed shaft for preventing the distribution ring from rotating with respect to the fixed shaft.

Hydraulically operated continuously variable transmission

A hydraulically operated continuously variable transmission includes a hydraulic motor coupled to an output shaft, a hydraulic pump coupled to an input shaft, and a closed hydraulic circuit interconnecting the hydraulic motor and the hydraulic pump. The hydraulic motor has an annular array of slidable motor plungers disposed around an axis of rotation thereof and slidably disposed in respective cylinder holes defined in a motor cylinder, the motor cylinder having an annular array of communication ports disposed around the axis of rotation and communicating with the cylinder holes. The hydraulic motor also has a distribution ring supported on a fixed shaft and rotatable relative to and slidable against an end face of the motor cylinder, the distribution ring having a suction port for communicating with the communication ports corresponding to those motor plungers which are in an expansion stroke, and a discharge port for communicating with the communication ports corresponding to those motor plungers which are in a contraction stroke. The suction and discharge ports are arcuate in shape and extend substantially along the annular array of communication ports, the suction and discharge ports having outer peripheral edges having a radius greater than the radius of a circumscribed circle of the communication ports and inner peripheral edges having a radius smaller than the radius of an inscribed circle of the communication ports.

Growing community of inventors

Utsunomiya, Japan

Akihito Okuda