JPH02113156A - Control device for speed change of tractor - Google Patents

Abstract

PURPOSE:To make it possible to perform suitable control for respective works by changing control content of clutch-on/off operation, gear change operation, and brake operation according to kinds of work. CONSTITUTION:For example, control content at shift-down operation changes according to kinds of work input to CPU 22 from a control mode switch 26. In the case of draft control at a plow working, normal control of clutch-on is performed after clutch-off and one stage shift down. When the engine load increases over a certain value, shift-up operation is not performed. On the other hand, in the case of plow depth control at a rotary working, brake is actuated at the same time as clutch-off and after one stage shift-down, the clutch is gradually on and the brake is returned to the non-acting side. In this way, as the output from the CPU 22 to solenoid valves V1-V7 is changeovered according to the kinds of working, safe and good working condition can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a speed change control device that controls the speed change operation of a tractor.

[Prior Art] An electronically controlled speed change control device that automatically performs a gear change operation and a gear change operation when changing gears is employed in tractors and the like.

[Problems to be Solved by the Invention] The conventional speed change control device described above is such that when a rotary tiller is attached to a tractor for tilling work, if the clutch is disengaged during gear change, the reaction force of the rotary tiller causes the vehicle body to shift. Sometimes progress is made.

For this reason, good tillage conditions could not be obtained and it was also dangerous.

[Means for Solving the Problems] In order to solve the above problems, the present invention has the following configuration.

That is, the speed change control device according to the present invention is a speed change control device for a tractor that automatically controls clutch engagement/disengagement operations, gear change operations, and brake operations, and adjusts the clutch operation according to the type of work. It is characterized by the ability to change the control details for on/off operations, gear change operations, and brake operations.

[Function] The system automatically controls clutch engagement/disengagement, gear change operation, and brake operation during gear shifting, and changes the control content depending on the type of work, so each work This allows suitable control to be carried out, resulting in good working conditions.

[Example] Fig. 1 is a power transmission system diagram of a tractor which is an example of the present invention, in which the rotational power of the engine 1 is transmitted to the driven side via the clutch 2, and is shifted by the main and auxiliary transmission devices 4.5. and drives the drive wheels 6.6. Drive wheels6.
6 is provided with a brake device 7.

The main and auxiliary transmissions 4.5 are each capable of shifting into four gears, and the main transmission 4 uses cylinder CI as a shift conversion means.
, C2 and valves Vl, V2, and the sub-shift trace N3 includes cylinders C3, C4 and valves V3, V4. The clutch 2 has an operating fork connected to a clutch pedal 10 and a cylinder C5 whose pressure is controlled by a valve 5, and the clutch can be operated by either the pedal or the cylinder. Brake equipment M7 also has brake pedal 1
1 or left and right brake operation cylinders C6 and C7 controlled by valves V6 and V7 can be operated. Each of the above cylinders Cl-C
Stroke sensors 5l-S7 are respectively attached to the cylinders 7 and 7 for detecting their contracted states. In addition, rotation speed sensors R1 and R2 detect the engine rotation speed of the rotary drive shaft, the rotation speed after the clutch, and the rotation speed after gear shifting.
, R3 are provided, respectively. clutch? , Main and sub-shift traces! 4.5 and the brake device 7 are controlled by a speed change control device 20 within the control box 13.

FIG. 2 is a block diagram of the speed change control device, in which the detection results of each stroke sensor 5l-37 are input to the CPU 22 via the A/D converter 21, and the detection results of each rotation speed sensor are directly input to the CPU 22. has been done. When a shift is set by the operation switch 24 of the main and auxiliary transmissions, an output is output to the solenoid valve V5 to disengage the clutch 2, and
A gear change is performed by outputting an output to solenoid valves 1 to V4 to achieve the set shift. When the gear change is completed, clutch 2 is engaged. When the clutch operation switch 25 is turned on by depressing the clutch pedal 10 during automatic control,
The command from the pedal side takes priority and automatic control is stopped.

On the other hand, when a work machine such as a plow or a rotary tiller is attached to a tractor and work is being carried out, speed change control is performed according to the type of work, for example, as follows.

First, let's take plowing work as an example. During this work, draft control using traction force is normally employed as the working machine elevation control mode.

As for shift control, only downshifting is performed when the engine drops due to an increase in engine load. In addition, in the case of rotary tillage work, depth control is adopted as the work equipment elevation control mode, but as for speed change control, when the running latch 2 is turned off, the vehicle body is moved by the reaction force of the rotary tiller. The brake device 7 is operated to prevent the vehicle from moving forward. In some cases, instead of activating brake equipment M7, P
The TO clutch (not shown) may be disengaged to temporarily stop power transmission to the working machine.

To illustrate these controls, for example, the control contents when downshifting differs depending on the type of work input from the control mode switch 26, as shown in the flowchart of FIG.

For draft control during plowing, normal control is performed by disengaging the clutch, shifting down one gear, and then connecting the clutch.Upshifting is not performed when the engine load increases above a certain level. . On the other hand, in the case of plowing depth control during rotary work, the clutch is disengaged and the brake is activated, and after downshifting by one gear, the clutch is gradually engaged and the brake is gradually returned to the non-operating side. During rotary work,
Since the brake is activated at the same time as the clutch is operated, the machine will not move forward due to the rotational reaction force of the tiller's rotary blade even if the clutch is released.

Incidentally, data indicating the states of the clutch 2, the main and auxiliary transmissions 4-5, and the brake device 7 is also transmitted to the engine control unit 27 and display unit 28.

[Effects of the Invention] As is clear from the above description, the tractor gear shift control device according to the present invention controls clutch engagement/disengagement operations, gear change operations, and brake operations during gear shifts depending on the type of work. This makes it possible to perform control suitable for each task, resulting in safe and good working conditions.

[Brief explanation of drawings]

FIG. 1 is a power transmission system diagram of a tractor as an example of the present invention, FIG. 2 is a block diagram of a speed change control device, and FIG. 3 is a flowchart showing the control contents thereof. DESCRIPTION OF SYMBOLS 1... Engine, 2... Clutch, 4... Main transmission, 5... Sub-transmission, 6... Driving wheel, 7...
- Brake device, 20... Speed change control device, 26...
Control mode switch・Figure 3

Claims (1)

[Claims] (1) A tractor speed change control device that automatically controls clutch engagement/disengagement, gear change operation, and brake operation, and the clutch engagement/disengagement operation and gear change operation according to the type of work. and a speed change control device for a traveling vehicle, characterized in that the content of control of brake operation is changed.