Kubota Corporation

Yoshinobu Murayama

Takashi Yoshii

Tetsuaki Hayashi

Kenzo Sada

Mitsuhiro Kutomi

A planetary gear type forward and backward drive switching apparatus, comprising a sun gear mounted on an input transmission shaft, a carrier mounting planetary gears meshing the sun gear and rotatable about the transmission shaft, a ring gear meshing the planetary gears and rotatable about the transmission shaft, and a friction brake mechanism for selectively braking rotations of the carrier and the ring gear, including a ring-formed main brake body having braking faces for acting on side faces of the carrier and the ring gear, the main brake body being shiftable axially of the transmission shafts for selectively braking the carrier and the ring gear, a clutch mechanism for selectively transmitting rotational outputs of the carrier and the ring gear to an output transmission shaft, and a control lever for controlling the forward and backward drive switching apparatus. According to this planetary gear type forward and backward drive switching apparatus, the control lever provides a forward drive by braking the ring gear and at the same time by operatively connecting the carrier to the output transmission shaft and provides a backward drive by braking the carrier and at the same time by operatively connecting the ring gear to the output transmission shaft.

Transmission system for vehicle having planetary gear type forward and

A change speed apparatus for a tractor comprising a combination of frictional stepless change speed means and planetary reduction means. A large diameter gear is used to drive the frictional stepless change speed means by means of engine output, and the frictional stepless change speed means includes a large diameter driven disc which engages an outer periphery of an internal gear of the planetary reduction means to be axially movable but not rotatable relative to the internal gear. The planetary reduction means is located in a space defined by the large diameter gear and the frictional stepless change speed means.

Change speed apparatus for a tractor

An agricultural tractor comprising differential case, a transmission case, a speed change case interposed between the two cases and directly coupled thereto, and a speed change mechanism contained in the speed change case and adapted to provide a great reduction ratio. The speed change case is not integral with the two other cases.

Agricultural tractor

A tractor travelling system transmission mechanism for providing tractor travelling system stepless speed change including the stop status of a tractor, and tractor forward/backward changeover, by using a friction type stepless transmission means, a planet reduction gearing and a forward/reverse changeover gearing, which is independently disposed without commonly utilizing the friction type stepless transmission means or the planet reduction gearing as a forward/reverse changeover means.

Tractor travelling system transmission mechanism

In a farm tractor of four wheel drive type, a speed change device for a power takeoff shaft projecting from a rear portion of a transmission case for driving a work implement attached to the rear end of the tractor is mounted in the rear portion of the transmission case, and a main shaft to receive output of the engine, a pinion shaft for driving the rear wheels and a transmission shaft for driving the front wheels are mounted in the front half of the transmission case with minimum spacing between the three shafts. This arrangement permits the transmission case to be compact in the vertical as well as transverse directions and provides a large space in the tractor underbelly for attaching a work implement.

Transmission for a farm tractor of four wheel drive type

A tractor transmission mechanism in which power ON/OFF operations of the travelling system and the PTO system may be carried out in succession by double action clutch means by utilizing a tractor transmission case of the type in which power ON/OFF operations of the travelling system and the PTO system are carried out at the same time by a main clutch.

Tractor transmission mechanism

A speed change mechanism for a transmission comprises a main shaft provided with a plurality of power transmitting gears, and a propelling speed change gear system and a power takeoff speed change gear system supported on the opposite sides of the main shaft in parallel thereto. Each of the propelling and power takeoff speed change systems includes a speed change shaft freely rotatably carrying a suitable number of speed change gears meshing with the power transmitting gears on the main shaft at all times. The speed change shaft accommodates an axially slidable speed change rod which, when moved, forces pins outward or inward radially of the shaft to couple the speed change shaft to the corresponding speed change gear or disconnect the shaft from the gear. The freely rotatable speed change gears are held against axial movement, while axially slidable engaging members which are otherwise provided between the adjacent speed change gears are eliminated. The transmission therefore has a shortened axial length and does not require a clutch which must be usually provided between the engine and the main shaft. The propelling speed change system further incorporates a creeping assembly of the planetary roller type for super-speed reduction and is provided with a secondary speed change assembly. The transmission also includes a power takeoff assembly for driving the front wheels of the tractor utilizing the secondary speed change assembly.

Transmission for tractors

In a power transmission system in which the torque delivered to an input shaft is transmitted to an output shaft via a planetary gear speed reduction mechanism, a stepless speed change system comprising a stepless speed change mechanism including a disk operatively connected to a gear mounted on the input shaft, a roller in contact with the disk and shiftable diametrically of the disk in a direction intersecting the axis of rotation of the disk, and a handle lever for shifting the roller, the roller being rotatable by the disk in a positive or reverse direction or stoppable when positioned at the center of rotation of the disk; and a worm and a worm wheel for transmitting the positive or reverse rotation of the roller to an internal gear of the planetary gear mechanism. When the output shaft is subjected to a load, part of the resulting counteracting torque is fed to the input shaft through the stepless speed change mechanism.

Growing community of inventors

Sakai, Japan

Yoshinobu Murayama