EP-4497617-B1 - WORK VEHICLE

Inventors

• ITO, HIROKAZU
• SHIBATA, TAKASHI

Dates

Publication Date

20260513

Application Date

20240708

Claims (5)

1. A work vehicle comprising: a first motor (21); a second motor (22); a first transmission mechanism (30) configured to transmit motive power from the first motor to a working power output section; a second transmission mechanism (40) configured to transmit motive power from the second motor to a traveling power output section (14,15), characterized in that it comprises: a first inverter (23) connected to the first motor; a second inverter (24) connected to the second motor; and a cooling device (60) configured to circulate and supply a refrigerant to the first motor, the second motor, the first inverter, and the second inverter, in that the cooling device circulates and supplies the refrigerant in such a manner that the refrigerant passes through the first inverter and the second inverter before passing through the first motor and the second motor, and in that the first motor (21) is located above the second motor (22), the first inverter (23) being attached to a lateral portion of the first motor (21) and the second inverter (24) being attached to a lateral portion of the second motor (22).
2. The work vehicle according to claim 1, wherein the cooling device (60) circulates and supplies the refrigerant in such a manner that the refrigerant passes through the second inverter (24) before passing through the first inverter (23).
3. The work vehicle according to claim 1 or 2, wherein the cooling device (60) circulates and supplies the refrigerant in such a manner that the refrigerant passes through the second motor (22) before passing through the first motor (21).
4. The work vehicle according to any one of claims 1 to 3, wherein the second transmission mechanism (40) includes: a planetary gear mechanism (41) configured to generate combined motive power by combining motive power received from the first motor (21) with motive power received from the second motor (22), and output the combined motive power; and a travel transmission section (42) configured to transmit the combined motive power output by the planetary gear mechanism to the traveling power output section (14,15).
5. The work vehicle according to claim 4, further comprising: a control device (50) configured to control rotation of the first motor (21) and control rotation of the second motor (22); and an operating device (51) configured to issue a forward travel command and a reverse travel command to the control device, wherein in response to receiving the forward travel command, the control device controls rotation of the second motor (22) in such a manner that the combined motive power output by the planetary gear mechanism (41) is used as forward motive power, and in response to receiving the reverse travel command, the control device (i) controls rotation of the first motor (21) in such a manner that the first motor decelerates or stops, and (ii) controls rotation of the second motor (22) in such a manner that motive power output by the planetary gear mechanism is used as reverse motive power.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work vehicle. 2. Description of the Related Art As disclosed in Patent Document 1 (JP 2022-77306A), there is a work vehicle (tractor) that includes a first motor, a first transmission mechanism (first input gear, second gear) that transmits motive power generated by the first motor to a working power output section (first output shaft), a second motor, and a second transmission mechanism (second input shaft, second input gear, third gear, planetary gear mechanism, first gear, switching mechanism, transmission mechanism, differential device) that transmits motive power generated by the second motor to a traveling power output section (second output shaft). JP 2022-77306 discloses a work vehicle according to the preamble of claim 1. SUMMARY OF THE INVENTION In some work vehicles of this type, inverters are connected to the first motor and the second motor. If the temperature of any of the motors or the inverters rises too high, a failure will occur in the motor or the inverter, and therefore it is necessary to stop operation of the motor or the inverter before the temperature rises too high. In other words, the time that work can continuously be performed is determined by the temperatures of the motors and the inverters. There is demand for a work vehicle that can continuously perform work for a long period of time. The present invention provides a work vehicle that can extend the time that work can be continuously performed with a simple structure. A work vehicle according to an aspect of the present invention is defined in claim 1. According to this configuration, the first inverter, the second inverter, the first motor, and the second motor are cooled by the refrigerant, thus making it possible to suppress a rise in the temperature of the first inverter, the second inverter, the first motor, and the second motor. The first inverter and the second inverter are cooled by the refrigerant before the first motor and the second motor are cooled, and therefore the first inverter and the second inverter, which are preferably kept at a lower temperature than the first motor and the second motor, are cooled efficiently. The structure of the cooling device can be made simpler than in the case of a configuration in which the refrigerant is circulated and supplied individually to the first inverter, the second inverter, the first motor, and the second motor. Since the first inverter, the second inverter, the first motor, and the second motor are cooled by the refrigerant, and furthermore, the first inverter and the second inverter are cooled efficiently, it is possible to suppress a rise in the temperature of the first inverter, the second inverter, the first motor, and the second motor, and furthermore, the time that operation can be continued can be extended with a cooling device having a simple structure. In an aspect of the present invention, it is preferable that the cooling device circulates and supplies the refrigerant in such a manner that the refrigerant passes through the second inverter before passing through the first inverter. According to this configuration, in the case where a motor having a lower output than the first motor is used as the second motor, the second inverter, which is connected to the second motor that has a lower output than the first motor and which is less likely to rise in temperature than the first inverter connected to the first motor, is cooled by the refrigerant before the first inverter, and thus the second inverter is cooled more efficiently than in the case where the refrigerant cools the second inverter after the first inverter. In an aspect of the present invention, it is preferable that the cooling device circulates and supplies the refrigerant in such a manner that the refrigerant passes through the second motor before passing through the first motor. According to this configuration, in the case where a motor having a lower output than the first motor is used as the second motor, the second motor, which is less likely to rise in temperature than the first motor, is cooled by the refrigerant before the first motor, and thus the second motor is cooled more efficiently than in the case where the refrigerant cools the second motor after the first motor. In an aspect of the present invention, it is preferable that the second transmission mechanism includes: a planetary gear mechanism configured to generate combined motive power by combining motive power received from the first motor with motive power received from the second motor, and output the combined motive power; and a travel transmission section configured to transmit the combined motive power output by the planetary gear mechanism to the traveling power output section. According to this configuration, even if the rotation direction and the rotation speed of motive power input from the first motor to the planetary gear mechanism are co