Search

US-12617268-B2 - Work vehicle

US12617268B2US 12617268 B2US12617268 B2US 12617268B2US-12617268-B2

Abstract

A work vehicle includes a prime mover; a transmission device; and an axle. The transmission device includes first and second transmission sections. The first transmission section is switchable into a decelerating power transmission mode and an accelerating power transmission mode. The axle is driven at a first drive rate with the first transmission section in the accelerating power transmission mode and the second transmission section in a transmission mode for a maximum speed and at a second drive rate with the first transmission section in the decelerating power transmission mode and the second transmission section in the transmission mode for a maximum speed. The first drive rate is higher than the second drive rate.

Inventors

  • Hiroki Bessho

Assignees

  • KUBOTA CORPORATION

Dates

Publication Date
20260505
Application Date
20250422
Priority Date
20240502

Claims (4)

  1. 1 . A work vehicle, comprising: a prime mover; a continuously variable transmission device comprised of an input shaft, an output shaft, an input pulley, an output pulley, and an endless belt; a transmission device configured to receive motive power from the prime mover via the continuously variable transmission device, adjust the motive power, and output the motive power as adjusted; and an axle drivable by the motive power from the transmission device, the transmission device comprising a first transmission section and a second transmission section connected to each other in series in a motive power transmission system for transmitting the motive power from the prime mover to the axle, the first transmission section comprising: a first power transmission shaft upstream in a motive power transmission direction; a second power transmission shaft downstream in the motive power transmission direction; and a first power transmission wheel and a second power transmission wheel each detachably attachable to each of the first power transmission shaft and the second power transmission shaft, and wherein: the first transmission section is switchable (i) in response to the first power transmission wheel being attached to the first power transmission shaft and the second power transmission wheel being attached to the second power transmission shaft, into a decelerating power transmission mode in which the first power transmission wheel and the second power transmission wheel decrease motive power transmitted from the first power transmission shaft to the second power transmission shaft and (ii) in response to the first power transmission wheel being attached to the second power transmission shaft and the second power transmission wheel being attached to the first power transmission shaft, into an accelerating power transmission mode in which the first power transmission wheel and the second power transmission wheel increase the motive power transmitted from the first power transmission shaft to the second power transmission shaft, the transmission device is switchable into (i) a first maximum speed power transmission mode in which the first transmission section is in the accelerating power transmission mode, and the second transmission section is in a transmission mode for a maximum speed and (ii) a second maximum speed power transmission mode in which the first transmission section is in the decelerating power transmission mode, and the second transmission section is in the transmission mode for a maximum speed, and the transmission device is configured to, in the first maximum speed power transmission mode, cause the axle to be driven at a first drive rate and, in the second maximum speed power transmission mode, cause the axle to be driven at a second drive rate, the first drive rate is higher than the second drive rate.
  2. 2 . The work vehicle according to claim 1 , wherein: the first transmission section comprises a first transmission case containing the first power transmission wheel and the second power transmission wheel, and the second transmission section comprises a second transmission section separate from the first transmission case.
  3. 3 . The work vehicle according to claim 1 , wherein: the first power transmission wheel is a first gear, and the second power transmission wheel is a second gear engageable with the first gear and having an outer diameter larger than an outer diameter of the first gear.
  4. 4 . The work vehicle according to claim 1 , wherein: the first power transmission wheel is a first belt pulley, and the second power transmission wheel is a second belt pulley coupled to the first belt pulley with use of an endless belt and having an outer diameter larger than an outer diameter of the first belt pulley.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to Japanese Patent Application No. 2024-074761 filed May 2, 2024, the disclosure of which is hereby incorporated by reference in its entirety. BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a work vehicle. Description of Related Art Japanese Unexamined Patent Application Publication, Tokukai, No. 2003-081144 discloses a track (crawler travel device) including a drive wheel (sprocket) attachable to an axle (rear axle), a front guide wheel (front tension wheel), a rear guide wheel (rear rotation wheel), two or more ground wheels (ground rotation wheels), and a crawler belt. SUMMARY OF THE INVENTION There has been a demand for a work vehicle capable of traveling with use of not only wheels but also tracks (crawler travel devices). A track may include a drive wheel attachable to an axle. The drive wheel typically has an outer diameter smaller than that of a wheel. With tracks attached, a work vehicle travels at a speed lower than in the case of traveling with use of wheels, even in response to the axles being driven at a speed equal to that for the case of traveling with use of wheels. Such a work vehicle, which is capable of traveling at a restricted maximum speed with wheels attached, is only capable of traveling at a speed lower than the restricted maximum speed with tracks attached. The present invention provides a work vehicle capable of traveling with use of tracks at a maximum travel speed equal to or not so different from a predetermined maximum travel speed as compared to the case of traveling with use of wheels. A work vehicle according to the present invention includes: a prime mover; a transmission device configured to receive motive power from the prime mover, adjust the motive power, and output the motive power as adjusted; and an axle drivable by the motive power from the transmission device, the transmission device including a first transmission section and a second transmission section connected to each other in series in a motive power transmission system for transmitting the motive power from the prime mover to the axle, the first transmission section including: a first power transmission shaft upstream in a motive power transmission direction; a second power transmission shaft downstream in the motive power transmission direction; and a first power transmission wheel and a second power transmission wheel each detachably attachable to each of the first power transmission shaft and the second power transmission shaft, the first transmission section being switchable (i) in response to the first power transmission wheel being attached to the first power transmission shaft and the second power transmission wheel being attached to the second power transmission shaft, into a decelerating power transmission mode in which the first power transmission wheel and the second power transmission wheel decrease motive power transmitted from the first power transmission shaft to the second power transmission shaft and (ii) in response to the first power transmission wheel being attached to the second power transmission shaft and the second power transmission wheel being attached to the first power transmission shaft, into an accelerating power transmission mode in which the first power transmission wheel and the second power transmission wheel increase the motive power transmitted from the first power transmission shaft to the second power transmission shaft, the transmission device being switchable into (i) a first maximum speed power transmission mode in which the first transmission section is in the accelerating power transmission mode, and the second transmission section is in a transmission mode for a maximum speed and (ii) a second maximum speed power transmission mode in which the first transmission section is in the decelerating power transmission mode, and the second transmission section is in the transmission mode for a maximum speed, the transmission device being configured to, in the first maximum speed power transmission mode, cause the axle to be driven at a first drive rate and, in the second maximum speed power transmission mode, cause the axle to be driven at a second drive rate, the first drive rate being higher than the second drive rate. The above configuration sets an appropriate difference between the drive rate of the axle in the first maximum speed power transmission mode and that in the second maximum speed power transmission mode on the basis of the difference between the outer diameter of each wheel and that of the drive wheel of each track (crawler travel device). The transmission device is switched into the first high-speed power-transmitting mode with the wheels attached and into the second high-speed power-transmitting mode with the tracks attached. This achieves an equal or substantially equal circumferential speed for both the wheels and the respective drive wheels of