Travel control system of construction machine

• US 10,640,951 B2
• Filed: 06/29/2016
• Issued: 05/05/2020
• Est. Priority Date: 07/03/2015
• Status: Active Grant

• Current Assignee: Caterpillar Sarl (Caterpillar Incorporated)
• Original Assignee: Caterpillar Sarl (Caterpillar Incorporated)
• Inventors: Murota, Isao, Hoshaku, Shota, Funabiki, Naoto
• Primary Examiner(s): Boehler, Anne Marie M
• Application Number:
  US15/741,723
• Publication Number:
  US 20180202127A1
• Time in Patent Office: 1,406 Days
• CPC Class Codes: B62D 1/12 Hand levers
• CPC Class Codes: B62D 1/22 Alternative steering-control elements, e.g. for teaching purposes
• CPC Class Codes: B62D 11/003 Electric or electronic control systems
• CPC Class Codes: B62D 11/02 by differentially driving ground-engaging elements on opposite vehicle sides
• CPC Class Codes: B62D 11/04 by means of separate power sources
• CPC Class Codes: E02F 3/32 working downwardly and towards the machine, e.g. with backhoes
• CPC Class Codes: E02F 9/2004 Control mechanisms, e.g. control levers control levers per se G05G
• CPC Class Codes: E02F 9/2012 Setting the functions of the control levers, e.g. changing assigned functions among operations levers, setting functions dependent on the operator or seat orientation
• CPC Class Codes: E02F 9/2246 Control of prime movers, e.g. depending on the hydraulic load of work tools
• CPC Class Codes: E02F 9/225 Control of steering, e.g. for hydraulic motors driving the vehicle tracks steering in general B62D
• CPC Class Codes: E02F 9/2253 Controlling the travelling speed of vehicles, e.g. adjusting travelling speed according to implement loads, control of hydrostatic transmission
• CPC Class Codes: E02F 9/2285 Pilot-operated systems
• CPC Class Codes: E02F 9/2292 Systems with two or more pumps
• CPC Class Codes: E02F 9/26 Indicating devices E02F5/145 takes precedence

Abstract

To reduce load on the operator and to establish traveling stability in the steering operation of a construction machine that has a pair of right and left traveling devices, and an engine as a driving power to the right and left traveling devices, a controller is provided which is responsive to a switch for traveling to drive or stop both a right and a left traveling devices. A switch for steering causes the controller to change the direction of travel of the construction machine, and the controller also acts to reduce the engine speed in accordance with the operation amount of the switch for steering.

Claims

1. A travel control system for a construction machine, the construction machine including

a left traveling device and a right traveling device;

an engine operatively coupled to the left traveling device and the right traveling device for transfer of traveling power to the left traveling device and the right traveling device;

left and right manipulators for traveling that are configured to direct traveling power to the left traveling device and the right traveling device, respectively;

a work device for executing work other than traveling; and

a manipulator for work that is operated to drive the work device, the travel control system comprising;

a switch for traveling that is provided separately from the left and right manipulators for traveling and configured to output a signal irrespective of a position of the left and right manipulators for traveling to drive and stop both the left traveling device and the right traveling device,

a manipulator for steering that is configured to output a signal to change a direction of travel of the construction machine, the manipulator for steering being configured for manipulation in a left direction and a right direction, the manipulator for steering being biased toward a neutral position disposed between the left direction and the right direction; and

a controller operatively coupled to the switch for traveling and the manipulator for steering, the controller being configured to

activate a travel mode in response to an input from the switch for traveling,

reduce a rotational speed of the left traveling device and reduce a rotational speed of the engine in response to the manipulator for steering being moved toward the left direction and in response to the activation of the travel mode,

reduce a rotational speed of the right traveling device and reduce the rotational speed of the engine in response to the manipulator for steering being moved toward the right direction and in response to the activation of the travel mode, and

reduce the rotational speed of the engine by a speed magnitude that is proportional to a distance of movement of the manipulator for steering away from the neutral position, during the travel mode.

2. The travel control system according to claim 1, wherein the manipulator for work includes an operating lever disposed on a left side or a right side of a seat for an operator, and

the switch for traveling and the manipulator for steering are disposed in a grip portion of the operating lever.

3. The travel control system according to claim 1, wherein the controller is further configured to

receive traveling input signals from the left and right manipulators for traveling,

receive working input signals from the manipulator for work, and

deactivate the travel mode in response to the traveling input signals or the working input signals, thereby disabling control of the left traveling device and the right traveling device in response to manipulation of the manipulator for steering.

4. The travel control system according to claim 1, further comprising a lock mechanism that prohibits driving of the left traveling device, the right traveling device, and the work device.

5. The travel control system according to claim 1, wherein the controller is further configured to activate a standby mode, in which the driving of the left traveling device and the right traveling device is put on hold, when the switch for traveling is operated while the left traveling device and the right traveling device are stopped.

6. The travel control system according to claim 5, further comprising notification means, wherein the controller is further configured to

notify an operator, via the notification means, when the standby mode is activated, and

activate the travel mode when the switch for traveling is operated within a predetermined time period after activation of the standby mode.

7. The travel control system according to claim 1, wherein the controller is further configured to operate each of the left traveling device and the right traveling device at a predetermined rotational speed in response to

the manipulator for steering being located in the neutral position, and

the activation of the travel mode.

8. The travel control system according to claim 1, wherein the controller is further configured to operate the left traveling device at a first reduced rotational speed and operate the right traveling device at a predetermined rotational speed in response to the manipulator for steering being moved toward the left direction, the first reduced rotational speed being less than the predetermined rotational speed.

9. The travel control system according to claim 8, wherein the controller is further configured to

reduce the rotational speed of the left traveling device in proportion to a distance of movement of the manipulator for steering along the left direction, and

maintain operation of the right traveling device at the predetermined rotational speed in response to the manipulator for steering being manipulated along the left direction.

10. The travel control system according to claim 8, wherein the controller is further configured to operate the right traveling device at a second reduced rotational speed and operate the right traveling device at the predetermined rotational speed in response to the manipulator for steering being moved toward the right direction, the second reduced rotational speed being less than the predetermined rotational speed.

11. The travel control system according to claim 10, wherein the controller is further configured to

reduce the rotational speed of the left traveling device in proportion to a distance of movement of the manipulator for steering along the left direction, and

maintain operation of the right traveling device at the predetermined rotational speed in response to the manipulator for steering being manipulated along the left direction.

12. The travel control system according to claim 11, wherein the controller is further configured to

reduce the rotational speed of the right traveling device in proportion to a distance of movement of the manipulator for steering along the right direction, and

maintain operation of the left traveling device at the predetermined rotational speed in response to the manipulator for steering being manipulated along the right direction.

13. A construction machine, comprising:

a left traveling device and a right traveling device;

an engine operatively coupled to the left traveling device and the right traveling device for transfer of traveling power to the left traveling device and the right traveling device;

left and right manipulators for traveling that are configured to direct traveling power to the left traveling device and the right traveling device, respectively;

a work device for executing work other than traveling;

a manipulator for work that is operated to drive the work device;

a switch for traveling that is provided separately from the left and right manipulators for traveling and configured to output a signal irrespective of a position of the left and right manipulators for traveling to drive and stop both the left traveling device and the right traveling device;

a manipulator for steering that is configured to output a signal to change a direction of travel of the construction machine, the manipulator for steering being configured for manipulation in a left direction and a right direction, the manipulator for steering being biased toward a neutral position disposed between the left direction and the right direction; and

a controller operatively coupled to the switch for traveling, the manipulator for steering, the engine, the left traveling device, and the right traveling device, the controller being configured to

activate a travel mode in response to an input from the switch for traveling,

reduce a rotational speed of the left traveling device and reduce a rotational speed of the engine in response to the manipulator for steering being moved toward the left direction and in response to the activation of the travel mode,

reduce a rotational speed of the right traveling device and reduce the rotational speed of the engine in response to the manipulator for steering being moved toward the right direction and in response to the activation of the travel mode, and

reduce the rotational speed of the engine by a speed magnitude that is proportional to a distance of movement of the manipulator for steering away from the neutral position, during the travel mode.

14. The construction machine according to claim 13, wherein the work device includes a shovel, and in which an upper rotating body is supported in a rotatable manner on a lower traveling body and which is provided with display means for displaying a direction of travel of the lower traveling body with respect to the upper rotating body.