JPS5914709A - Apparatus for controlling revolving time in tractor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for turning a tractor on a headland at the end of a field, and more specifically to a control device for automatically raising a working machine required when the tractor turns. .

Generally, when turning a tractor, (1) decelerating the traveling speed by lowering the engine accelerator lever, (2) operating the lift door of the work equipment by raising the lift arm, and (3) rotating the steering handle. Aircraft turning operation by
(4) Operate the aircraft to enter a straight course by rotating the steering handle in the opposite direction; (5) lift down the work equipment by lowering the lift arm; (6) accelerate the traveling speed by raising the accelerator lever. 6 stages (1) ~
Performing the operation in (6) requires a high degree of skill, and
In addition, unskilled operators may cause errors or delays in operating procedures, reducing work efficiency and making the field tilled unevenly.
Furthermore, accidents such as damage to work equipment, injury to operators, etc. have occurred due to incorrect operation. In addition, after turning the tractor, when the steering wheel is returned to the straight-ahead state, the work equipment is automatically lowered using a fat system (Japanese Patent Publication No. 38-239
(Refer to Publication No. 62), however, this device only automated the above-mentioned operation (5), which had a relatively sufficient margin, while the tractor was in a low-speed state, and the operator was unable to perform many other operations. However, the above-mentioned drawbacks still have not been solved, and the steering handle is generally returned to the straight-ahead position before the tractor turn is completed, and then overhandled in the opposite direction, causing the tractor to return to the straight-ahead course. Because of the approach, there was a risk that the work equipment would descend during the turn. In addition, a speed control device (Japanese Patent Publication No. 41-6687) was devised, which is equipped with an engine speed control device so that the engine speed decreases as the steering angle of the steering device increases. However, with this device, when the handle is returned, the engine speed increases, so the tractor's traveling speed increases in the later stage of the turning stroke, and the above-mentioned straight course entry operation (4) and work equipment lift down operation (5) ) could become difficult.

Therefore, the present invention installs a turning angle detection sensor capable of detecting when the aircraft is turning, and further communicates the hydraulic pressure with the control valve of the hydraulic cylinder for controlling the toe arm via a switching valve and a pressure reducing valve. When the aircraft is moving straight, reduced pressure is applied to the control valve of the hydraulic cylinder via the pressure reducing valve, and when the aircraft is making a sharp turn, the hydraulic pressure is applied directly to the control valve of the hydraulic cylinder via the switching valve, and the control valve is switched to lift the aircraft. This book aims to provide a turning control device for a tractor, which eliminates the above-mentioned drawbacks by configuring the arm to rise rapidly.

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, the tractor 1 has front wheels 2.
It has a fuselage 3 supported by a and rear wheels 2b,
The aircraft body 3 is equipped with an engine 5 and a driver's seat 6. Furthermore, a three-point link device 10 consisting of a top link 7 and a lower link 9 is installed at the rear of the fuselage 3.
A lower rotary 11 is attached to the lower link 9, and a hydraulic cylinder 12 (see Figures 5 and 6) K is attached to the lower link 9.
The lift rod 1 is moved up and down by the lift rod 1
They are connected via 5. Further, the driver's seat 6 is provided with a steering handle 1G, an accelerator lever 17, a manual start push button switch 19, etc., and the rotary 11 is still equipped with a tilling blade 20, a rotary cover 21, and a rotary cover 21 that is pivotally supported. A rear cover 22 and the like are provided, and tillage depth detection wheels 23 supported on a shaft that substantially coincides with the axis of the tiller blade 20 are provided on the left and right sides of the tiller blade 20, respectively. .

As shown in detail in FIG. 3, a lever 27 fixed to a cover shaft 26 is supported on the cover case 25 of the engine. It is connected to a link 33 via a hydrodynamic cylinder 31 and another rod 32, and the link 33 is further connected to an accelerator lever 17 via an accelerator lever Jl 135. Therefore, in addition to being operated by the accelerator lever 17, the cover lever 27 is also used to operate the hydraulic cylinder 31.
The length l of the tip p1°h1 pivot shaft and the link tip pivot shaft can be controlled by changing.

On the other hand, the pitman arm 36, which is linked to the steering handle 16, is attached to the front wheel 2a, which is pivotally supported by the kingpin 40-, via the drive link 37 and the knuckle arm 39, as shown in detail in FIG. connected. Left and right turning angle detection sensors 411 and 41r are installed before and after the pitman arm 36, and when the arm 36 rotates by a predetermined amount Xt and Xr, the detection sensor 411 or 11r is turned on. In addition, X 1ma
x and Xrmax respectively indicate the left and right maximum displacement angles.

In addition, FIG. 5 is a diagram showing the hydraulic circuit according to this embodiment.
12 is a hydraulic cylinder that operates the lift arm 13, and is operated by a lowering electromagnetic pilot valve 4:3, an ascending electromagnetic pilot valve 45, a switching valve 46, a relief valve 47, and a relief valve 49; 7a is a hydraulic cylinder constituting the top link 7, and therefore the top link is configured to be expandable, and the electromagnetic switching valve 5
Operated by 0. And terminal a of each solenoid
, b, c.

d is operated based on signals from the lift arm angle detection sensor, the plow shooting angle detection sensor, the tillage depth detection sensor 23, etc., to control the lifting and lowering of the working machine in a pattern optimal for rotary work or plow work.

Furthermore, in the figure, 31 is kat (Nareno (-27 is 1r + J
This double-acting hydraulic cylinder is operated by an electromagnetic switching valve 51. Further, 52 is a pump, 53 is a flow rate distribution valve, 55 is a relief valve, 56 is an electromagnetic switching valve, 57 is a flow rate distribution valve, and 59 is an operator t! It is a variable throttle valve that adjusts the control speed of the engine rotational speed according to the state, and the flow rate distribution valve 53 is moved by pressure oil from the pump 52 (throttle against the engine 53a). Then, pressure oil at a constant pressure is allowed to flow through the pipe line n, and high pressure oil is allowed to flow through the pipe line. Further, the high pressure oil pipe 11 is branched into an electromagnetic switching valve 56 and a flow rate distribution valve 57, and a left/right rotation detection sensor 411 or 41
When r is on, that is, when the tractor is turning, terminal e is energized and the electromagnetic switching valve 56 is connected, and high-pressure oil is sent directly to the lift arm lifting cylinder 12 and the engine rotation control cylinder 31, causing the tractor to move straight ahead. Occasionally, oil under reduced pressure by the flow distribution valve 57 is sent to each cylinder 12.31.

Furthermore, FIG. 6 is a control electric circuit diagram according to this embodiment, in which 411.41r is a left and right turning angle detection sensor, LE is an engine rotation speed setting device during turning, and SE
is the engine speed sensor. Further, 60 is a comparison circuit that compares the current rotation speed with the set engine rotation speed, and 61 is a conversion circuit that converts the engine into an operation determined by an internal program according to a signal from the turning angle detection sensor. Based on this, each of the terminals a to e of the electromagnetic switching valve 56, the electromagnetic pilot valves 43 and 45 for lifting the lift arm, and the electromagnetic switching valve 50 for expanding and contracting the top link is energized, and is output to the conversion circuit 62.

Further, the conversion circuit 62 determines the state based on the signals from the comparison circuit 60 and the conversion circuit 61, and energizes each terminal f or g of the electromagnetic switching valve 51 for engine speed control. In the figure, 63 is an automatic/manual changeover switch, and 19 is a manual start push button switch, which is directly connected to power supply B.

Since this embodiment has the above configuration, the tractor 1
When traveling straight, the steering wheel 16 is within a predetermined range from the straight traveling state, and the pitman arm 36 is in the left/right turning angle detection sensor 41! , 41r, these sensors are in the off state. In this state, the electromagnetic switching valve 56 is connected to the terminal e.
The high pressure side of the flow rate distribution valve 53, on which the high pressure of the pump 52 is applied, is reduced in pressure by the flow rate distribution valve 57, and the relief valve 4 for lifting and lowering the lift arm is closed.
7 and a switching valve 51 for engine speed control. Note that the pressure reducing side n of the flow rate distribution valve 53 is always acting on the top link expansion/contraction switching valve 50. Therefore, in the case of rotary work as shown in Figs. 1 and 2, the engine load is further controlled by tilling depth control based on the tillage depth detection Iia 23, or in the case of book work, by resistance control or slip rate control. As a result, the working machine 11 is raised and lowered and the engine speed is controlled either automatically or manually by the operator, but in the tilling work state, the control is performed slowly based on the reduced pressure hydraulic oil. .

When the tractor 1 reaches the headland at the end of the field and turns the steering knob 16 sharply to the right or left, the front wheels 2a are steered via the pitman arm 36, drag link 37, etc. At the same time, the pitman arm 36 moves to the left or right within a predetermined range XI.

When the turning angle detection sensor 41 rotates by more than Xr,
Turn on 1 or 41r. Then, based on the conversion circuit 61, the electromagnetic switching valve 56 is brought into communication by energizing the terminal e.
In addition to applying high pressure directly to each valve 47 and 51, the terminal of the lifting pilot valve 45 is energized to close the relief valve 47, and high pressure oil is force-fed to the hydraulic cylinder 12, rapidly moving the tow arm 13. At the same time, based on the conversion circuit 62, the terminal f of the switching valve 51 is energized to contract the double-acting hydraulic cylinder 31, and the cover lever 27 is rotated in the deceleration direction to rapidly set the engine speed. The rotation speed is reduced to the speed set by the controller LE, and the tractor 1 is decelerated. The tractor turns without any problem, but when the reversal is completed and it enters the straight course, it performs an overhand link further in the opposite direction from the straight ahead position, and the reverse turning angle detection sensor 41r or 41
Turn on 1. Then, based on the conversion circuit 61, the lowering pyro energizes the terminal a of the lift valve 43 to switch the switching valve 46, drain the hydraulic cylinder 12, and open the lift arm 13.
is lowered and set to a predetermined plowing depth before turning, and then based on the conversion circuit 61, the terminal g of the switching valve 51 is energized to extend the double-acting hydraulic cylinder 31, and the engine rotation speed is set to the pre-turning engine rotation speed, Further, the energization to the terminal e of the switching valve 56 is stopped, and the reduced pressure hydraulic oil by the flow rate distribution valve 57 is applied to each valve 47, 51 again. As a result, the tractor 1 is moved straight ahead to perform the next stage of tilling work.

If the straight direction of the aircraft becomes optimal during the overhand link, by pressing the push button switch 19, the signal from the conversion circuit 61 is prioritized and the valve 43.
51, the working machine can be lowered and the engine speed can be increased.

In the above embodiment, the pitman arm 36 was used to detect when the tractor 1 was turning, but as shown in FIG.
, 41'r may be installed. In addition, 65 in the figure is a tie rod.

Furthermore, as shown in detail in FIG. 8, a serpentine traveling direction detector 67 is rotatably installed on the rear cover 22 of the rotary 11 with a boss 66, and the detector 67 detects when the tractor is turning. It's okay.

Further, the working machine is not limited to the rotary, but it goes without saying that the present invention can also be applied to other ground-based working machines such as plows, soil cultivators, mowers, and fertilizers. Furthermore, the flow distribution valve 57 that applies pressure reduction to each valve 47, 51 may be another pressure reduction valve.

As explained above, according to the present invention, the hydraulic pressure is communicated with the control valve 47 of the hydraulic cylinder 12 for controlling the lift arm through the switching valve 56 and the pressure reducing valve 57 in parallel. Although the work equipment 11 can be controlled slowly and accurately by applying reduced pressure hydraulic oil to the switch valve 5, when turning, the switching valve 5
6, the hydraulic pressure can be applied directly to the control valve 47 to rapidly control the lifting of the working machine.

Although the work equipment is controlled by detecting machine rotation based on 41'r and 67, the lift-up operation can be performed automatically without any delay, so even inexperienced operators can operate it accurately and reliably. At the same time, operator fatigue can be significantly reduced, and headlands can be reduced to improve work efficiency. Furthermore, when the descending control of the work equipment and the speed increase control of the engine speed are performed based on the overhand link, the same turning angle detection sensor is used to control the rise and fall of the work equipment, and the deceleration and speed increase control of the engine speed. This makes it possible to reduce the number of sensors, and it is also possible to reliably prevent the turning work from becoming difficult due to an increase in the engine rotational speed when the working machine is lowered early.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing a tractor to which the present invention is applied, Fig. 2 is a side view thereof, Fig. 3 is a side view showing a hydraulic cylinder for engine speed control, and Fig. 4 is a turning angle detection sensor. FIG. 5 is a hydraulic circuit diagram used for automatic control, FIG. 6 is an electric circuit diagram thereof, FIG. 7 is a plan view showing another turning angle detection sensor, and FIG. 8 is a diagram showing another turning angle detection sensor. It is a figure which shows a turning angle detection sensor, (a) is a side sectional view, (b) is a bottom view. 1...Tractor, 12...Hydraulic cylinder,
13...Lift arm, 411,41r.

Claims (1)

[Claims] (1) In a tractor equipped with an engine and having a lift arm that can be raised and lowered by a hydraulic cylinder, a turning angle detection sensor that can detect when the machine is turning is installed,
Furthermore, the hydraulic pressure is connected to the control valve of the hydraulic cylinder for controlling the toe arm through a switching valve and a pressure reducing valve in parallel, and when the aircraft is moving straight, the reduced hydraulic pressure is applied to the control valve of the hydraulic cylinder via the pressure reducing valve. 7. A turning control device for a tractor, which applies hydraulic pressure directly to a control valve of a hydraulic cylinder via a switching valve when the machine turns, and switches the control valve to rapidly raise a tow arm.