Kubota Corporation

Ryoma Iwase

Tomonari Tsuchida

Tetsuo Yamaguchi

Tomoyuki Tanaka

Takahiro Matsuo

Atsushi Jinnai

Hidetoshi Hana

Hiroyuki Aikawa

Rikuto Araki

Keitaro Morinaga

Atsuro Hayami

Tsuyoshi Gono

Yuji Hirase

Takuya Nishikubo

Susumu Takeoka

Makoto Kubota

Komei Yamawaki

Kazuhiro Wada

Koki Date

Yusuke Nabana

Yoshiki Fujiyama

Naoyuki Miyamoto

Yosui Nishijima

Hiroyuki Sadamoto

Satoru Nagano

Takuma Hokeguchi

Tsubasa Kawazoe

A work vehicle includes a controller configured or programmed to include an input revolutions number calculator to calculate an input revolutions number, and a vehicle speed controller switchable between a first vehicle-speed control mode and a second vehicle-speed control mode. In the first vehicle-speed control mode, the vehicle speed controller is configured or programmed to control a vehicle speed of the work vehicle based on a value detected by an input rotation sensor. In the second vehicle-speed control mode, the vehicle speed controller is configured or programmed to control the vehicle speed based on a value calculated by the input revolutions number calculator.

Work vehicle

A clutch hub includes oil supply holes extending therethrough to supply lubricating oil from an interior of the clutch hub toward first clutch plates and second clutch plates. An injection port to allow injection of the lubricating oil into the interior of the clutch hub is located inside of the clutch hub between the clutch hub and a rotation axis of a clutch body. The clutch hub includes an inner circumferential portion including an opposing portion opposing the injection port, and a first portion closer to a first end portion of the clutch hub than the opposing portion in a direction extending along the rotation axis. The first portion includes an inclined inner circumferential surface structured such that a radius of the clutch hub decreases toward the first end portion.

Hydraulic clutch and work-vehicle travel power transmission apparatus including the hydraulic clutch

A hydraulic clutch includes friction plates to transmit motive power, a piston movable between (i) a pressing position, at which the piston presses the friction plates for the hydraulic clutch to be engaged to transmit motive power, and (ii) a separated position, at which the piston is spaced apart from the friction plates for the hydraulic clutch to be disengaged to block motive power, the piston being movable into the pressing position in response to receiving hydraulic fluid to move the piston toward the pressing position, and a holder to (i) hold the piston at an intermediate position between the pressing position and the separated position in response to the piston coming into contact with the holder and (ii) release the piston from the intermediate position.

Hydraulic clutch, travel power transmission device, and work vehicle

There is provided a work vehicle including a partition wall to keep partition between a first space zone as part of an internal space of the transmission case in which a differential mechanism is located and a second space zone as part of the internal space which is adjacent to the first space zone. An upper space is disposed above the partition wall and configured to allow lubricating oil scooped up from the first space zone by a ring gear to flow in the second space zone. A flow-out path is disposed below the upper space and configured to allow the lubricating oil to flow out of the second space zone to the first space zone.

There is provided a work vehicle including an oil outlet port and a partition part. The oil outlet port opens to a bottom portion in one end side of a transmission case in a vehicle body front-back direction and a vehicle body left-right direction. The oil outlet port takes out a lubricating oil from an interior of the transmission case. The partition part divided an internal space of the transmission case into a first space zone along a sidewall portion of the transmission case, and a second space zone other than the first space zone. The partition part brings the first space zone into a sealed state.

An electromagnetic valve control device includes a current gear ratio obtainer to obtain a current gear ratio as a ratio of an output revolutions number of a driver and an output revolutions number of a transmission, a current electric current value obtainer to obtain a current electric current value as a value of an electric current to be inputted to a first electromagnetic valve or a second electromagnetic valve, and a switching controller to, based on the current electric current value and a gear ratio difference as a difference between a target gear ratio and the current gear ratio, perform electromagnetic valve switching control to switch between use of the first electromagnetic valve to control a pump swash plate and use of the second electromagnetic valve to control the pump swash plate.

Electromagnetic valve control device and work vehicle

A continuously variable powertrain device for a work vehicle includes a hydraulic static transmission to output a continuously shifted motive power while continuously varying a velocity of a motive power received from an engine, a planetary transmission to receive the motive power from the engine and the continuously shifted motive power and to output a compound motive power, a pressure detector to detect a hydraulic pressure in a closed circuit of the hydraulic static transmission, a planetary clutch mechanism to switch a shift level of the planetary transmission, and a powertrain controller to control actuation of the hydraulic static transmission and the planetary transmission based on a shift command.

Continuously variable powertrain device for work vehicle and work vehicle including the same

A continuously variable powertrain device for a work vehicle includes a continuously variable transmission to output a continuously shifted motive power while continuously varying a speed of a motive power received from an engine, a planetary transmission to receive the motive power from the engine and the continuously shifted motive power and to output a compound motive power, a planetary clutch to switch a shift level of the planetary transmission a forward-reverse direction switch to receive the compound motive power and to output either a forward motive power or a reverse motive power, rotation detectors, and a powertrain controller.

A traveling transmission device of a tractor including a transmission case to which power from an engine is inputted via an input shaft, a speed changer transmission section provided inside the transmission case and configured to input power from the input shaft and to speed-change the inputted power and output it, and a rear wheel differential mechanism provided inside the transmission case and configured to input power outputted from the speed changer transmission section and transmit the inputted power to left and right rear wheels. The speed changer transmission section includes a plurality of speed changer sections configured to speed-change power from the input shaft by a gear coupling mechanism and a multiple-disc clutch and output it, and, inside the transmission case, an oil feeding pipe extends upwardly of the speed changer transmission section and a discharge nozzle connects to respective portions of the plurality of speed changer sections.

Traveling transmission device of tractor

A work vehicle includes a restrainer vehicle speed setter to set a restrainer vehicle speed, and a switch restrainer to permit switching of the forward/backward travel switching device while a detected vehicle speed is lower than the restrainer vehicle speed and prevent switching of the forward/backward travel switching device while the detected vehicle speed is a high speed not lower than the restrainer vehicle speed.

An electromagnetic valve control device includes a control signal generator to, through feedback control involving an environmental coefficient, generate a control signal intended for at least one electromagnetic valve and corresponding to a target electric current value, a coefficient determiner to determine an environmental coefficient during a learning period from a start of a driver operation to an end of a predetermined time, and an operation limiter to limit respective operations of the at least one electromagnetic valve and a gear transmission during the learning period.

A power transmission device for a work vehicle includes a transmission case, a gear transmission housed in the transmission case and configured to transmit power to a travel device, and a transmission gear provided in the gear transmission in a state of sitting in lubricating oil stored in an internal space of the transmission case, the transmission case being provided with a wall part supporting a support shaft of the transmission gear in a state of being adjacent to the transmission gear, and the wall part being provided with a cover part protruding toward the outer periphery of the transmission gear from the wall part and covering the transmission gear.

Power transmission device for work vehicle

Provided are a speed changer device, a forward/reverse switchover device for converting output of the speed changer device into forward traveling power and reverse traveling power, a rear wheel differential mechanism for inputting output of the forward/reverse switchover device and transmitting it to rear wheels, and a gear transmission mechanism for transmitting power of an output shaft of the forward/reverse switchover device to an input shaft of the rear wheel differential mechanism. A transmission case is separable into a front case portion accommodating the speed changer device and a rear case portion accommodating the forward/reverse switchover device, the rear wheel differential mechanism and the gear transmission mechanism. The gear transmission mechanism is detachably provided at a portion of the inside of the transmission case which portion corresponds to a front end portion of the rear case portion.

A work vehicle includes a hydrostatic stepless speed changer device configured to speed-change driving power of an engine steplessly, a plurality of planetary gear speed changer devices configured to speed-change the driving power speed-changed by the stepless speed changer device, a plurality of clutch mechanisms corresponding to the plurality of planetary gear speed changer devices in order to take off the driving powers from these plurality of planetary gear speed changer devices individually, and a traveling speed changer device for speed-changing and transmitting the driving powers transmitted from the plurality of clutch mechanisms to a traveling mechanism. The plurality of planetary gear speed changer devices the plurality of clutch mechanisms and the traveling speed changer device are accommodated in a transmission case.

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Osaka, Japan

Ryoma Iwase