Yanmar Co., Ltd.

Yanmar Agricultural Equipment Co., Ltd.

Yukio Kubota

Kunihiko Sakamoto

Fumio Ishibashi

Yasuo Noma

Akifumi Kuroda

Masakazu Komatsu

Shuji Shiozaki

Junichi Hitachi

Hisanori Mori

Takeshi Oouchida

Hiroshi Matsuyama

Susumu Akashima

Yuuji Kitasaka

Susumu Nochi

Yasuhiko Hori

A hydraulic transmission () has an electric actuator () for changing its output/input rotation speed ratio. A controller () of the actuator memorizes a command current value to the actuator supposing that load is not applied on the hydraulic transmission, and calculates a value of load applied on the hydraulic transmission by calculating a difference between an actual command current value to the actuator and the memorized command current value. A command current value is compensated based on the value of load, and the actuator receives feedback to be controlled. A vehicle may have a differential mechanism (), which combines rotation powers on input side and output side of the hydraulic transmission. A detector () detects rotation speed of a main speed change output shaft () serving as an output shaft of the differential mechanism. If the detected rotation speed differs from target rotation speed of the shaft () determined based on operation of a speed change operation tool, the actuator is forcedly controlled. This difference is supposed to be caused by load applied on the hydraulic transmission, whereby the load is calculated.

Hydraulic transmission vehicle

A hydraulic continuously variable transmission has a variable displacement type first hydraulic system having a first plunger and a plunger abutting section which actuates the first plunger, and a second hydraulic system having a second plunger and provided with an output rotary section which rotates with abutment on the second plunger. A cylinder block rotates about an axis and has a first plunger hole and a second plunger hole which respectively retain the first and second plungers. A hydraulic closing circuit connects the first and second plunger holes and circulates a working oil between the first and second plunger holes. The continuously variable transmission has a distributing valve for controlling circulation of the working oil in the hydraulic closing circuit, a valve hole, formed in the cylinder block, for retaining the distributing valve, and a shaft which penetrates the cylinder block. The shaft and the cylinder block rotate synchronously and the output rotary section is rotatably supported around the shaft. The valve hole is formed in parallel to the shaft, and restriction means is arranged inclined with respect to the shaft and rotates in synchronism with the cylinder block to reciprocate the distributing valve with the distributing valve being restricted.

Hydraulic continuously variable transmission and power transmission apparatus

A hydraulic transmission () has an electric actuator () for changing its output/input rotation speed ratio. A controllerof the actuator memorizes a command current value to the actuator supposing that load is not applied on the hydraulic transmission, and calculates a value of load applied on the hydraulic transmission by calculating a difference between an actual command current value to the actuator and the memorized command current value. A command current value is compensated based on the value of load, and the actuator receives feedback to be controlled. A vehicle may have a differential mechanism (), which combines rotation powers on input side and output side of the hydraulic transmission. A detector () detects rotation speed of a main speed change output shaft () serving as an output shaft of the differential mechanism. If the detected rotation speed differs from target rotation speed of the shaft () determined based on operation of a speed change operation tool, the actuator is forcedly controlled. This difference is supposed to be caused by load applied on the hydraulic transmission, whereby the load is calculated.

A tractor having right and left traveling crawlers () installed thereon, comprising a hydraulic transmission swing mechanism (), a forced-diff () for driving a crawler driving sprocket (), and an engine (), a hydraulic transmission straight-ahead driving mechanism (), and a transmission case () disposed from the front side to the rear side of a machine body in that order, wherein an allowance for heat radiation is provided to a space under a machine floor for storing the hydraulic transmission straight-ahead driving mechanism () to eliminate the problem of the machine floor becoming too high, and the forced-diff () is driven by the hydraulic transmission swing mechanism () with a simple structure.

Tractor

A hydraulic and mechanical composite continuously variable transmission (HMT) is disclosed. The HMT includes a hydraulic continuously variable transmission (HST) and a mechanical speed change mechanism using a group of planetary gears as the differential part. The output rotation of the HST and the rotation of the input part of the mechanical speed change mechanism that receives power from the engine are transmitted to the differential part which translates the rotation to a speed change output shaft. The speed change input part is formed at one end of a pump shaft and the differential input part is coaxially formed at the other end thereof. Further, the operator may manually set the speed ratio via electrical means on the mechanical speed chance mechanism.

Continuously variable transmission

Growing community of inventors

Osaka, Japan

Yukio Kubota