Kubota Corporation

Shigekazu Hasegawa

Tetsu Fukui

Yoshimi Oota

Satoshi Machida

Takeshi Ura

Norimi Nakamura

Yoshiyuki Katayama

Shigeaki Okuyama

Toshiya Fukumoto

Tetsuya Nishida

Muneji Okamoto

Yoshimi Ota

Naoki Okita

Shouhei Nakai

A transmission system having a first clutch for receiving engine drive, a second clutch disposed downstream of the first clutch with respect to a direction of drive transmission, change speed gearing disused between the first clutch and second clutch, a first transmission shaft for transmitting drive from the first clutch to the change speed gearing, a second transmission shaft for transmitting drive in varied speeds from the change speed gearing to the second clutch, a third transmission shaft for transmitting drive from the second clutch to drive wheels, and a third clutch for transmitting drive at a low speed to the first transmission shaft. The first clutch and second clutch are disengageable upon start of a shifting operation of the change speed gearing, and re-engageable upon completion of the shifting operation. To obtain matching between rotating rates of an input line and an output line of the change speed gearing, the third clutch transmits the low speed drive to the first transmission shaft upon disengagement of the first clutch and second clutch, and breaks the drive upon completion of the shifting operation of the change speed gearing.

Transmission system for transmitting engine drive in varied speeds to

A control system for controlling change speed gearing (A) of a vehicle for transmitting output of an engine (1) in varied speeds to wheels. This system has a first clutch mechanism mounted in a drive transmitting line between the engine and the change speed gearing, the first clutch mechanism including two hydraulically operable clutches (5, 6) for forward drive and backward drive, and a backward-forward changeover valve (32) for selectively operating the two clutches; a second clutch mechanism mounted in a drive transmitting line between the change speed gearing and the wheels, the second clutch mechanism including a quick operating clutch (19) for quickly making and breaking drive transmission, and a clutch control valve (26) for controlling the quick operating clutch; actuators (T1, T2) for shifting the change speed gearing; and a control unit (30) operatively connected to the backward-forward changeover valve, clutch control valve and actuators. In response to start of a shifting operation of the actuators, the quick operating clutch is disengaged and an engaged one of the hydraulically operable clutches of the first clutch mechanism is reduced to a predetermined low pressure. In response to completion of the shifting operation of the actuators, the quick operating clutch is engaged and the clutch of the first clutch mechanism is gradually raised from the predetermined low pressure.

Propelling transmission structure for a working vehicle

A four wheel drive working vehicle having transmission clutches separately operable for driving right and left rear wheels. Power for driving right and left front wheels is transmitted thereto from a change speed device through a front differential, while power for driving the rear wheels is transmitted thereto from the change speed device through the transmission clutches, respectively. When the front wheels are steered from a straight running position beyond a predetermined angle in order to turn the vehicle, the transmission clutch corresponding to the rear wheel lying on the inside of the turn is disengaged while the transmission clutch corresponding to the outside rear wheel remains engaged. Consequently, the rear wheel lying on the inside of the turn and describing the smallest turning radius is placed in free rotation state. The working vehicle can change running directions and make small, sharp turns smoothly without a rear differential.

Four wheel drive working vehicle having transmission clutches separately

A rolling clutch apparatus having two one-way transmission mechanisms arranged axially of a drive shaft and a driven shaft. Each transmission mechanism includes an inner ring defining a conical outside surface, an outer ring disposed coaxially with the inner ring and defining a conical inside surface, and tapered rollers arranged between the conical surfaces of the inner and outer rings. The transmission mechanisms are shiftable at the same time so that the rollers in one of the transmission mechanisms are displaced axilly to be pressed between the conical surfaces of the inner and outer rings whereby the inner and outer rings rotate together to transmit drive.

Conical roller type clutch apparatus

A grass cutting system for use on a walking operator type or a riding type lawn mower as mounted between front and rear wheels. This grass cutting system comprises a cutting blade rotatable on a vertical axis, a grass catcher disposed above the cutting blade and defining a top opening, and a housing surrounding the grass catcher. A cylindrical space is defined between the grass catcher and the housing, through which grass clippings are fed with air currents from the cutting blade to the grass catcher.

Grass cutting system having a grass catcher

A change speed control structure for a hydraulic transmission comprising a rotary valve for controlling a plurality of hydraulic actuators, a shift lever extending through a crooked guide groove, and a relay assembly for transmitting movements of the shift lever to the rotary valve on a reduced scale. The guide groove includes three straight portions extending parallel to one another in series and offset in a transverse direction thereof, each straight portion including a plurality of change speed positions. An adjacent pair of the straight portions are interconnected end to end by a bight portion.

Change speed control structure for hydraulic transmission

There is disclosed a plowing depth detecting system for a rotary plow adapted to detect an actual plowing depth on the basis of distance data with respect to the ground received from a distance sensor attached to the rotary plow which is vertically movably connected to a vehicle through a link mechanism. The distance sensor provides a microprocessor with distance data with respect to the ground rearwardly of the rotary plow. The microprocessor determines a value of actual plowing depth of the rotary plow on the basis of this distance data and a correction value according to a working condition of the rotary plow.

Plowing depth detecting system for rotary plow

A hydraulic construction for a working vehicle comprising a transmission case housing a hydraulic clutch and defining a lateral opening, and hydraulic control device mounted on an inner face of a cover attached to the transmission case to close the opening, the hydraulic control device acting to control oil flows to the hydraulic clutch. The hydraulic control device is hydraulically connectable to oil passage device connected to the hydraulic clutch when the cover is attached to the transmission case.

Transmission casing including a hydraulic clutch

A hydraulic circuit construction for a power shift transmission having logical operation valves mounted on a pressure oil supply passage connecting a hydraulic clutch to a pressure oil source, the logical operation valves being operable to engage and disengage the hydraulic clutch by opening and closing the pressure oil supply passage in response to a switching operation of a change speed device connected upstream of and in series to the hydraulic clutch. The pressure oil supply passage has mounted thereon a pressure control device including a first valve mechanism, a second valve mechanism and an orifice parallel-connected to the pressure oil supply passage, and an accumulator is mounted between the pressure control device and the hydraulic clutch to assure a speedy and smooth operation of the hydraulic clutch.

Hydraulic circuit construction for power shift transmission

A drive apparatus for a work vehicle such as a tractor is disclosed, with an engine, an input shaft coupled to the engine, a change-speed mechanism, a hydraulic clutch, an auxiliary change-speed mechanism and a reduction mechanism housed in a common transmission case. Power from the reduction mechanism is transmitted to the rear wheels through a rear differential and to the front wheels through a drive shaft and a front differential.

Drive apparatus

A seated-operator type tractor has a vehicle proper (1), equipped rearwardly thereof with a link mechanism (6) and a scraper (9) for ground-leveling. The vehicle (1) is further provided with: a position-controlling mechanism (34) for controlling up-and-down position of the scraper (9); an automatic control mechanism for maintaining the scraper (9) in its left-and-right horizontal posture, by a sensor (50) therefor; a controlling valve (24) for controlling blade-angle adjustment of the scraper (9); and a manual switch (47) disposed near at hand of the seated operator, for shifting over the vehicle (24).

Tractor with three-point linkage connecting scraper thereto and

An automatic position control apparatus for a ground working vehicle equipped with a liftable working implement. The control apparatus is adapted to automatically control lifting and lowering of the implement so that the deviation of the draft value of the implement acutally detected by a draft detector from the draft value preset by a draft setting unit is maintained within a permissible range preset by a sensitivity setting unit. The control apparatus is characterized in that the apparatus includes a detector for detecting that the deviation is not decreasing outside the permissible range above the maximum permissible value thereof so as to automatically control the lift of the implement only while the deviation detector is in detecting operation.

Growing community of inventors

Sakai, Japan

Shigekazu Hasegawa