Working vehicle

Patent metadata

Field	Value
Publication number	US-11248668-B2
Application number	US-202016950328-A
Country	US
Kind code	B2
Filing date	Nov 17, 2020
Priority date	Dec 2, 2019
Publication date	Feb 15, 2022
Grant date	Feb 15, 2022

Abstract

A working vehicle includes a first hydraulic clutch connected to the first traveling shaft, a second hydraulic clutch connected to the first traveling shaft separately from the first hydraulic clutch, a first gear mechanism to transmit, to a second traveling shaft, power from the first hydraulic clutch when the first hydraulic clutch is engaged and not to transmit, to the second traveling shaft, power from the first hydraulic clutch when the first hydraulic clutch is disengaged, and a second gear mechanism to transmit, to the second traveling shaft, power from the second hydraulic clutch when the second hydraulic clutch is engaged and not to transmit, to the second traveling shaft, power from the second hydraulic clutch when the second hydraulic clutch is disengaged.

First claim

What is claimed is:

1. A working vehicle comprising:
a first traveling shaft to be rotated by power of a prime mover;
a second traveling shaft to be rotated by the power of the prime mover and to transmit the power to a wheel;
a first hydraulic clutch connected to the first traveling shaft;
a second hydraulic clutch connected to the first traveling shaft separately from the first hydraulic clutch;
a first gear mechanism to transmit, to the second traveling shaft, power from the first hydraulic clutch when the first hydraulic clutch is engaged and not to transmit, to the second traveling shaft, power from the first hydraulic clutch when the first hydraulic clutch is disengaged;
a second gear mechanism to transmit, to the second traveling shaft, power from the second hydraulic clutch when the second hydraulic clutch is engaged and not to transmit, to the second traveling shaft, power from the second hydraulic clutch when the second hydraulic clutch is disengaged;
a hydraulic control valve having an aperture to be changed in accordance with a control signal, the hydraulic control valve being configured to supply operation fluid to the first and second hydraulic clutches and drain from the operation fluid the first and second hydraulic clutches; and
a controller device to gradually reduce a duty ratio of the control signal when any one of the first hydraulic clutch and the second hydraulic clutch is switched from being engaged to being disengaged.

2. The working vehicle according to claim 1 , comprising
a temperature detector device to detect temperature of operation fluid, wherein
the controller device changes the duty ratio based on the temperature of operation fluid detected by the temperature detector device.

3. The working vehicle according to claim 1 , comprising
an adjuster dial to be manually operated, wherein
the controller device changes the duty ratio based on operation of the adjuster dial.

4. The working vehicle according to claim 1 , wherein
the first gear mechanism includes a plurality of first gears engaged each other,
the second gear mechanism includes a plurality of second gears engaged each other, and
the plurality of second gears has a gear ratio providing a rotation speed of the second traveling shaft higher than another rotation speed of the second traveling shaft rotated with the plurality of first gears.

5. The working vehicle according to claim 4 , comprising
a temperature detector device to detect temperature of operation fluid, wherein
the controller device changes the duty ratio based on the temperature of operation fluid detected by the temperature detector device.

6. The working vehicle according to claim 4 , comprising
an adjuster dial to be manually operated, wherein
the controller device changes the duty ratio based on operation of the adjuster dial.

7. The working vehicle according to claim 4 , comprising
a third traveling shaft to be rotated by the power of the prime mover and to transmit the power to a rear wheel, wherein
the second traveling shaft transmits the power to a front wheel.

8. The working vehicle according to claim 7 , comprising
a temperature detector device to detect temperature of operation fluid, wherein
the controller device changes the duty ratio based on the temperature of operation fluid detected by the temperature detector device.

9. The working vehicle according to claim 7 , comprising
an adjuster dial to be manually operated, wherein
the controller device changes the duty ratio based on operation of the adjuster dial.

10. The working vehicle according to claim 7 , comprising:
a traveling body; and
a switching device to switch driving of the traveling body between two-wheel driving, four-wheel driving, and acceleration driving, wherein
the controller device disengages the first hydraulic clutch and the second hydraulic clutch in the two-wheel driving in accordance with the control signal, engages the first hydraulic clutch and disengages the second hydraulic clutch in the four-wheel driving in accordance with the control signal, and disengages the first hydraulic clutch and engages the second hydraulic clutch in the acceleration driving in accordance with the control signal.

11. The working vehicle according to claim 10 , comprising
a temperature detector device to detect temperature of operation fluid, wherein
the controller device changes the duty ratio based on the temperature of operation fluid detected by the temperature detector device.

12. The working vehicle according to claim 10 , comprising
an adjuster dial to be manually operated, wherein
the controller device changes the duty ratio based on operation of the adjuster dial.

13. The working vehicle according to claim 10 , wherein
the controller device gradually reduces the duty ratio of the control signal when the first hydraulic clutch is switched from being engaged to being disengaged.

14. The working vehicle according to claim 13 , comprising
a temperature detector device to detect temperature of operation fluid, wherein
the controller device changes the duty ratio based on the temperature of operation fluid detected by the temperature detector device.

15. The working vehicle according to claim 10 , wherein
the controller device gradually reduces the duty ratio of the control signal when the second hydraulic clutch is switched from being engaged to being disengaged.

16. The working vehicle according to claim 15 , comprising
a temperature detector device to detect temperature of operation fluid, wherein
the controller device changes the duty ratio based on the temperature of operation fluid detected by the temperature detector device.

17. The working vehicle according to claim 10 , wherein
the controller device gradually reduces the duty ratio of the control signal corresponding to the first hydraulic clutch and gradually increases the duty ratio of the control signal corresponding to the second hydraulic clutch when the first hydraulic clutch is switched to being disengaged and the second hydraulic clutch is switched to being engaged in accordance with the control signal.

18. The working vehicle according to claim 17 , comprising
a temperature detector device to detect temperature of operation fluid, wherein
the controller device changes the duty ratio based on the temperature of operation fluid detected by the temperature detector device.

19. The working vehicle according to claim 10 , wherein
the controller device gradually reduces the duty ratio of the control signal corresponding to the second hydraulic clutch and gradually increases the duty ratio of the control signal corresponding to the first hydraulic clutch when the second hydraulic clutch is switched to being disengaged and the first hydraulic clutch is switched to being engaged in accordance with the control signal.

20. The working vehicle according to claim 19 , comprising
a temperature detector device to detect temperature of operation fluid, wherein
the controller device changes the duty ratio based on the temperature of operation fluid detected by the temperature detector device.

Assignees

• Kubota Kk

Inventors

• Azuma Hitoshi
• Yamaguchi Tetsuo
• Ohara Shinji

Classifications

• B60K2023/0858

  with electric means, e.g. electro-hydraulic means · CPC title

• F16D2500/31493

  Switches on the dashboard · CPC title

• F16D2500/30803

  Oil temperature · CPC title

• F16H47/04 Primary

  the mechanical gearing being of the type with members having orbital motion · CPC title

• B60Y2200/221

  Tractors · CPC title