Speed control for working vehicle

• US 9,725,090 B2
• Filed: 07/22/2015
• Issued: 08/08/2017
• Est. Priority Date: 08/01/2014
• Status: Active Grant

• Current Assignee: Kubota Corporation
• Original Assignee: Kubota Corporation
• Inventors: Komatsu, Shigeru, Takahashi, Keiji
• Primary Examiner(s): Mawari, Redhwan K
• Assistant Examiner(s): Sood, Anshul
• Application Number:
  US14/806,021
• Publication Number:
  US 20160031443A1
• Time in Patent Office: 748 Days
• Field of Search: 701 93
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/101 Infinitely variable gearings
• CPC Class Codes: B60W 2300/152 Tractors
• CPC Class Codes: B60W 30/143 Speed control B60W30/16 takes precedence

Abstract

A speed control device in a traveling work vehicle changes a speed of rotational drive power from an engine to drive vehicle wheels and includes: a target speed calculator determining a target speed, based on operation deflection of a speed change device. A vehicle speed controller adjusting a speed change ratio based on the target speed. A vehicle speed obtainer obtaining an actual vehicle speed. A forcible target speed modifier forcibly modifying the target speed to a lower speed based on operation of a braking device. A release can treat an operation of the speed change device as a trigger to cancel the target speed forcibly modified by the forcible target speed modifier, and conforming the target speed to the actual vehicle speed.

Claims

1. A speed control device in a traveling work vehicle, the speed control device changing a speed of rotational drive power from an engine to drive vehicle wheels and comprising:

a speed change device;

a maximum speed definer defining a maximum speed of the traveling work vehicle;

a target speed calculator determining a target speed, based on operation movement or position of the speed change device;

a vehicle speed controller adjusting or changing at least one of;

engine revolutions; and

/or

a speed change ratio;

a vehicle speed obtainer obtaining an actual speed of the traveling work vehicle;

a braking device that is different and distinct from the speed change device and that is configured to brake the traveling work vehicle;

a forcible target speed modifier forcibly modifying the target speed to a lower speed based on operation or movement of the braking device; and

a release operable to treat an operation of the speed change device as a trigger to cancel the target speed forcibly modified by the forcible target speed modifier, and conform the target speed to the actual vehicle speed.

2. The speed control device according to claim 1, wherein the rotational drive power from the engine occurs via a continuously variable transmission mechanism.

3. The speed control device according to claim 1, wherein the target speed calculator calculating a speed ratio relative to the maximum speed defined by the maximum speed definer.

4. The speed control device according to claim 1, wherein the vehicle speed controller adjusts or changes the speed change ratio, wherein the traveling work vehicle includes a continuously variable transmission mechanism and wherein the speed change ratio is a speed change ratio of the continuously variable transmission mechanism.

5. The speed control device according to claim 1, wherein the maximum speed is at least one of:

a work travel mode maximum speed;

a road travel mode maximum speed having a higher speed than the work travel mode maximum speed; and

/or

a work travel mode maximum speed operating during a road travel mode.

6. The speed control device according to claim 5, further comprising:

a travel status determiner determining whether the traveling work vehicle is in a work travel state or a road travel state based on a detection signal from a status detection sensor detecting a status of the work vehicle.

7. The speed control device according to claim 5, wherein the work travel mode is set or activated when a travel status determiner determines that the traveling work vehicle is in the work travel state, and the road travel mode is set or activated when the travel status determiner determines that the vehicle is in the road travel state.

8. The speed control device according to claim 7, wherein, when a fixed speed change ratio mode is activated, the speed change ratio assumes a fixed speed change ratio mode, and the vehicle speed controller adjusts the engine revolutions of the engine based on the target speed.

9. The speed control device according to claim 5, wherein, when a fixed speed change ratio mode is activated, the speed change ratio assumes a fixed speed change ratio mode, and the vehicle speed controller adjusts the engine revolutions of the engine based on the target speed.

10. The speed control device according to claim 1, wherein, when a fixed speed change ratio mode is activated, the speed change ratio assumes a fixed speed change ratio mode, and the vehicle speed controller adjusts the engine revolutions of the engine based on the target speed.

11. The speed control device according to claim 10, wherein the speed change device is a multifunction lever that is hand and/or driver operable.

12. The speed control device according to claim 10, wherein the speed change device is settable in each of:

a first operation function activating a speed change operation; and

a second operation function activating the fixed speed change ratio mode.

13. The speed control device according to claim 12, wherein the speed change device is a multifunction lever that is hand and/or driver operable.

14. The speed control device according to claim 1, wherein the braking device is a brake pedal, such that movement of the brake pedal beyond a predetermined amount, the target speed is modified to become no speed or a zero-percent speed.

15. A speed control device in a traveling work vehicle, the speed control device changing a speed of rotational drive power from an engine to drive vehicle wheels and comprising:

a user hand operable speed change device;

a user foot operable braking device configured to brake the traveling work vehicle;

a control system configured to each of;

receive an input signal from the braking device;

define or set a maximum speed of the traveling work vehicle;

determine or set a target speed based on operation movement or position of the speed change device;

change or adjust at least one of;

engine speed;

transmission output speed; and

/or

a transmission speed change ratio;

obtain or determine an actual speed of the traveling work vehicle; and

lower the target speed based on operation or movement of the braking device,

wherein the target speed is configured to be modified by a forcible target speed modifier, and the control system is further configured to treat an operation of the speed change device as a trigger to cancel the target speed forcibly modified by the forcible target speed modifier, and conform the target speed to the actual vehicle speed.

16. The speed control device according to claim 15, wherein the braking device comprises a brake pedal sensor that outputs the input signal to the control system.

17. A speed control device in a traveling work vehicle, the speed control device changing a speed of rotational drive power from an engine to drive vehicle wheels and comprising:

a user operable speed change device;

a braking device that is different and distinct from the speed change device and that is configured to brake the traveling work vehicle;

a control system configured to each of;

define and/or set a maximum speed of the traveling work vehicle;

determine and/or set a target speed based on operation movement or position of the speed change device;

change or adjust at least one of;

engine speed;

transmission output speed; and

/or

a transmission speed change ratio;

obtain or determine an actual speed of the traveling work vehicle; and

automatically change the target speed based on operation or movement of the braking device,

wherein the target speed is configured to be modified by a forcible target speed modifier, and the control system is further configured to treat an operation of the speed change device as a trigger to cancel the target speed forcibly modified by the forcible target speed modifier, and conform the target speed to the actual vehicle speed.

18. The speed control device according to claim 17, wherein the braking device comprises a brake pedal and a brake pedal sensor, and the control system receives an input signal from the brake pedal sensor.