JP2000006608A - Tread changing device for work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change a tread as efficiently as possible at a proper speed by providing a means specifying the type of a work machine to be connected, and adjusting the tread changing speed based on this information. SOLUTION: A controller 13 is provided with a CPU serving as an arithmetic process section of various signals, a ROM storing a tread change control program, and a RAM temporarily storing the values of various setting units and sensors. A tread changing switch 15, a tread setting unit 16, a work machine specifying switch 17, stroke sensors 41L, 41R, a vehicle speed sensor 42 and a clutch pedal 12 are connected to the input side. The setting of the tread changing speed is changed in response to the type of the work machine specified by the work machine specifying switch 17. When a heavy work machine is connected, the load required for a tread change is large, thus the tread changing speed is slowed down.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tread changing device for changing and adjusting the distance between wheels of an agricultural or construction work vehicle.

[0002]

2. Description of the Related Art There is known an agricultural tractor in which a tread can be changed by sliding wheels to the left and right by an actuator such as a hydraulic cylinder. Conventionally, the tread change speed has always been constant.

[0003]

In order to change the tread efficiently, the tread changing speed may be increased. However, if the tread changing speed is too fast, especially when a heavy working machine is connected, the hydraulic system or An excessive load may be applied to the component for changing the tread, and the component may be damaged. Therefore, an object of the present invention is to make it possible to change a tread as efficiently as possible at an appropriate speed according to a working machine to be connected.

[0004]

Means for Solving the Problems In order to solve the above problems, the present invention is configured as follows. That is, the tread changing device for a work vehicle according to the present invention is a tread-adjustable work vehicle capable of selectively connecting various work machines, a means for detecting a weight of the work machine to be connected,
One of a means for setting the weight of the working machine to be connected and a means for specifying the model of the working machine to be connected is provided, and the tread change speed is adjusted based on information from the means. .

[0005]

Preferred embodiments of the present invention will be described below with reference to the drawings. The tractor 1 shown in FIG.
A four-wheel drive vehicle including a pair of left and right front wheels 2, 2 and rear wheels 3, 3, wherein an engine 5 is mounted at a front portion of the body,
A clutch case 6 is provided on the rear side, and a transmission case 7 is further provided on the rear side. The front wheels 2, 2 are supported to be steerable below the engine 5, and the rear wheels 3, 3 are mounted on rear axle housings 7a, 7a projecting left and right from the rear of the transmission case 7 so as to be capable of changing tread.

[0006] Fenders 8, 8 are attached from the front of the left and right rear wheels 3, 3 to above, and a seat 9 is installed between the left and right fenders. A steering handle 10 for steering the front wheels 2 is provided in front of the seat 9. Below the seat 9, a clutch pedal 11 for disengaging the main clutch in the clutch case 6 by stepping pressure operation is provided. When the clutch pedal 11 is depressed, it is detected by the clutch pedal switch 12. In addition, seat 9
A control box 14 for accommodating a controller 13 to be described later is provided beside the. On the upper surface of the control box 14, a tread change switch 1
5, a tread setting device 16, a work machine designation switch 17, and the like.

[0007] At the rear of the machine body, lift arms 21 and 21 are provided, which are vertically moved by an elevating cylinder 20. The distal ends of the lift arms and lower links 22 and 2 for mounting a working machine are provided.
2 are connected to the intermediate portion by lift rods 23, 23. By raising and lowering the lift arms 21 and 21, the working machine 25 supported by the three-point link mechanism including the lower links 22 and 22 and the top link 24 moves up and down. One of the lift rods 18 (the left side in the illustrated example) is a rolling cylinder, and the horizontal inclination of the working machine is adjusted by expanding and contracting the cylinder. The figure shows a state in which a rotary plow is connected as a working machine.

FIG. 2 is a horizontal sectional view of a part of the transmission case showing the rear wheel support. Rear wheel drive power taken out to the pinion shaft 30 via a transmission (not shown) is transmitted to the disc brake devices 32 and 3 via a rear wheel differential device 31.
2 is transmitted to the left and right relay shafts 33 having the rear axle 3 via the reduction gears 34.
5, 35. A spline is formed in the rear axles 35, 35, and the spline is formed on the rear axle 35, 35.
6 and 36 are fitted so as to rotate integrally and to slide left and right. The rear wheel axles 36, 36 are slidable with respect to the rear axle housings 7a, 7a.
7 and 37 are rotatably supported via bearings 38 and 38. The rear wheels 3, 3 are integrally attached to the rear wheel axles 36, 36.

At the front portions of the rear axle housings 7a, zoom cylinders 40L, 40R, which are actuators for changing the rear wheel tread L, are provided in the left-right direction. The pistons of the zoom cylinders 40L, 40R are connected to slide cases 37, 37, and the rear axles 36,
36 is slid left and right. The amount of expansion and contraction of the zoom cylinders 40L and 40R is determined by a stroke sensor
1L and 41R are detected. The left slide case 37 is provided with a vehicle speed sensor 42 for detecting the number of rotations of the rear wheel 3 to determine the vehicle speed.

A hydraulic circuit for operating the zoom cylinder is configured as shown in FIG. Pump P sucks oil from tank T, which also serves as a transmission case, and supplies it to left and right zoom cylinders 40L, 40R. Since the switching control valves 43L and 43R for switching the oil supply direction are provided for the left and right zoom cylinders 40L and 40R, both zoom cylinders can be operated individually. Switching control valve 4
3L (43R) is a solenoid valve, and solenoid 4
When 3aL (43aR) is excited, the zoom cylinder 40L
(40R) is extended and the solenoid 43bL (43b
When R) is excited, the zoom cylinder 40L (40R) contracts and operates, and if neither solenoid is excited, the operation of the zoom cylinder stops. Solenoid 43bL, 43
bR is driven by pulse energization from the controller 13. By changing the duty ratio of the pulse ON time, the operation speed of the zoom cylinder, that is, the tread change speed can be adjusted.

The controller 13 includes, as shown in FIG.
The system includes a CPU that is an arithmetic processing unit for various signals, a ROM that stores a tread change control program and the like, and a RAM that temporarily stores values of various setting devices and sensors. The tread change switch 15, tread setting device 16, work implement designating switch 17, stroke sensors 41L and 41R, vehicle speed sensor 42, and clutch pedal switch 12 are connected to the input side. On the output side, an extension solenoid 43aL and a contraction solenoid 43aR of a switching control valve 43L for controlling the left zoom cylinder are provided.
And a solenoid 43bL for extension and a solenoid 43bR for contraction of the switching control valve 43R for controlling the right zoom cylinder.
And are connected.

The controller 13 performs the following control (see FIG. 5). First, when the power is turned on, the values of various setting devices and sensors are read and stored in the RAM. When the tread change switch 15 is turned on in this state, the zoom cylinders 40L and 40R are operated in the following manner to change the tread so that the tread set by the tread setting device 16 is obtained. However, the vehicle speed sensor 42
If the vehicle speed detected in step (1) is 0 or a very low speed close to 0, the load is too large and the tread is not changed.
If the clutch pedal 11 is depressed during the tread change (the clutch pedal switch 12 is turned on), the tread change is stopped.

The zoom cylinders 40L and 40R are expanded and contracted so that the detection values of the stroke sensors 41L and 41R match the set values of the tread setting device 16.
The operation speed of the zoom cylinder, that is, the tread change speed is set stepwise as shown in the graph of FIG. That is, the change speed is gradually increased at the beginning of the operation, the change speed is maintained in the intermediate portion at the high speed, and the change speed is gradually reduced at the end of the operation. As a result, the tread change is completed as quickly as possible while preventing excessive load from being applied to the hydraulic system and the components for changing the tread at the beginning and end of the operation, so that the maneuverability is not impaired.

Further, the setting of the tread change speed is changed according to the type of the work equipment designated by the work equipment designation switch 17. For example, in the graph of FIG. 6, the solid line indicates the tread change speed when the weight of the specified work machine is heavy, and the broken line indicates the tread change speed when the weight of the specified work machine is light. When a heavy work machine is connected, the load required for changing the tread is large, so that the tread changing speed is reduced. Regardless of whether the working machine is light or heavy, the tread changing speed is set to a low speed at the beginning and end of the operation as described above. The work machines may be classified into three or more stages based on weight, and the tread changing speed may be changed according to the classification. Further, in the present embodiment, the weight of the work equipment is specified by specifying the model of the work equipment with the work equipment designating switch 17, but the means for setting the weight of the work equipment or the weight of the work equipment is actually reduced. A means for detecting may be provided, and the tread changing speed may be changed based on information on the weight of the work implement from the means.

While the tread is being changed, the stroke sensor 41
The actual tread change speed is calculated from the change in the L and 41R values, and the actual change speed is compared with the setting change speed.
If the actual change speed is lower than the setting change speed, it is determined that an excessive load is applied, and the output to the zoom cylinder is increased to control the actual change speed to approach the setting change speed.

Further, when the vehicle speed detected by the vehicle speed sensor 42 is equal to or higher than a predetermined speed, abrupt tread change is dangerous, so the setting change speed is corrected so that the tread change speed becomes slow. Instead of detecting the actual vehicle speed with the vehicle speed sensor 42, it may be determined whether or not the vehicle is in a high-speed running state from the shift position of the transmission.

[0017]

As is apparent from the above description, the tread changing device for a working vehicle according to the present invention detects the weight of the connected working machine or sets the weight of the connected working machine. The tread change speed is adjusted in accordance with the weight of the work equipment determined based on information from the means or the means for specifying the model of the work equipment to be connected. The tread can be changed efficiently without imposing an excessive load on the constituent members.

[Brief description of the drawings]

FIG. 1 is a side view showing a working state by a tractor.

FIG. 2 is a horizontal sectional view of a part of a transmission case.

FIG. 3 is a tread changing hydraulic circuit diagram.

FIG. 4 is a block diagram of a tread change control device.

FIG. 5 is a flowchart of tread change control.

FIG. 6 is a graph showing a relationship between a tread and a tread change speed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Tractor 2 Front wheel 3 Rear wheel 5 Engine 7 Transmission case 11 Clutch pedal switch 12 Clutch pedal switch 13 Controller 15 Tread change switch 16 Tread setting device 17 Work machine designation switch (means for designating the model of work machine) 40L, 40R Zoom cylinder 41L, 41R Stroke sensor 42 Vehicle speed sensor 43 Switching control valve

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ryota Nagano 1st Hachikura, Tobe-cho, Iyo-gun, Ehime Prefecture Iseki Agricultural Machinery Co., Ltd. Engineering Department

Claims (1)

[Claims] 1. A work vehicle capable of selectively connecting various work machines with a tread adjustable, means for detecting the weight of the work machine to be connected, means for setting the weight of the work machine to be connected, and A tread changing device for a work vehicle, comprising: a means for designating a model of a working machine to be connected; and adjusting a tread changing speed based on information from the means.