JPH0139723B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a tilling device on a traveling vehicle body that can be raised and lowered via a single-acting lift arm cylinder, and a control valve for raising and lowering operation is provided in a pressure oil supply path to the cylinder. A rotary cover of the tilling device is provided to be swingable, and a tillage depth control mechanism is provided that automatically operates the cylinder to maintain the swing angle of the rotary cover within a set range based on the displacement of the rotary cover. This invention relates to a riding-type cultivator equipped with an electric power tiller.

Conventionally, to configure the plowing depth control mechanism using the above, the amount of rocking displacement of the rotary cover is electrically detected using a potentiometer, etc., and the detected signal is corrected to determine the actual plowing depth. The control valve was configured to be detected and to automatically operate the control valve based on a comparison between the detection result and the set value by the setting device.
That is, tillage depth control was performed by electrically linking the rotary cover and the control valve.

However, since it incorporates an electrical control circuit for signal processing, it is expensive and has the disadvantage of being prone to failure.

SUMMARY OF THE INVENTION In view of the above points, it is an object of the present invention to make a simple improvement to a hydraulic circuit so that a plowing depth control mechanism can be constructed at low cost.

In order to achieve the above object, the present invention provides the above-mentioned riding type cultivator, in which the plowing depth control mechanism includes a pressure oil supply path between the control valve and the cylinder. A return path is connected to release the supplied pressure oil with the control valve in the raised operation position, and an opening adjustment valve is interposed in the return path, and the opening adjustment valve and the rotary cover are connected to the rotary cover. The rotary cover is interlocked and connected via a mechanical linkage mechanism so that as the rotary cover swings upward, the opening becomes smaller, and as the rotary cover swings downward, the opening becomes larger. Features.

In other words, there is back pressure in the lift arm cylinder due to the weight of the tiller, and if you adjust the balance between that back pressure and the pressure of the pressure oil supplied to the lift arm cylinder, the lift arm cylinder will always be Focusing on the ability to raise and lower the tillage device while supplying pressure oil, we connected a return path to a predetermined location of the pressure oil supply path, and installed an opening adjustment valve in the return path. The displacement of the rotary cover itself is applied as an operating force via a mechanical linkage mechanism, and when the rotary cover swings upward, the opening degree is reduced, the lift arm cylinder is extended against back pressure, and the tilling device is activated. raise it above the ground,
Conversely, when the rotary cover swings downward, the opening is increased, oil is drained from the lift arm cylinder by back pressure, the tilling device is lowered relative to the ground, and the tilling device is maintained at the set height relative to the ground. Let it happen.

Therefore, although it is a simple improvement of adding a return path and an opening adjustment valve to the conventional hydraulic circuit, it is possible to construct a plowing depth control mechanism with fewer failures and at a lower cost by using a mechanical coupling mechanism. Summer.

In particular, according to the present invention, when a plow device is installed in place of the tilling device and leveling work is performed,
By removing the mechanical linkage mechanism from the opening adjustment valve and interlockingly connecting the top link holder attached via a torsion bar and the opening adjustment valve via a draft rod, it is possible to reduce the ground depth even when working with a plow device. It can be carried out under a constant condition and has great practical effects.

Hereinafter, embodiments of the present invention will be described in detail based on illustrative drawings.

A rotary tilling device 3 is connected to the rear of the traveling vehicle body 1 via a three-point link mechanism 2 consisting of a top link 2a and a pair of left and right lower links 2b, 2b, and a rotary tiller 3 is connected to the lower links 2a, 2b and the upper part of the tractor 1. A pair of left and right lift arms 4, 4
are connected via lift rods 5, 5, and one single-acting hydraulic cylinder (hereinafter referred to as lift arm cylinder) is connected to the lift arms 4, 4.
6 are interlocked and connected to form a riding type cultivator.

The lift arm cylinder 6 is configured to supply pressure oil via a control valve 11 by a pump P driven by engine output, and an operating lever 9 is interlocked and connected to the control valve 11 via a link mechanism 8. At the same time, the lift arm 4 is interlocked and connected to the link mechanism 8 via the rod 10, and as the control valve 11 is operated by the operating lever 9, the lift arm cylinder 6 is operated and the lift arm 4 is
When the lift arm 4 is swung, the oscillating displacement of the lift arm 4 is fed back to the control valve 11 via the link mechanism 8, and when the lift arm 4 is swung to a position corresponding to the operating position of the operating lever 9, the control valve 11 is is automatically switched to a neutral state, and vertical movement of the tilling device 3 is automatically stopped.

In the figure, reference numeral 12 indicates a valve for adjusting the ascending and descending speed, and is designed to prevent the descending speed from increasing due to the weight of the tilling device 3.

Between the control valve 11 and the speed regulating valve 12, there is a return path 1 in the middle of the pressure oil supply path for releasing the supplied pressure oil.
3 are connected in communication, and an opening adjustment valve 14 is interposed in the return path 13, and by adjusting the opening of the valve 14, the back pressure from the lift arm cylinder 6 and the pressure oil supplied to the cylinder 6 are controlled. The height of the rotary tiller 3 is maintained stably by adjusting the balance with the pressure and maintaining the pressure balance between the two in equilibrium.

In the rotary tilling device 3, a rotary cover 15 is pivotally connected to a rotary frame 16 so as to be able to swing freely around the left-right axis Q of the vehicle body, and a swing arm 17 is interlocked and connected to the rotary cover 15;
A link mechanism 18 operatively connected to the opening adjustment valve 14 is connected via a push-pull wire 19, and a plowing depth setting lever 2 is connected to the link mechanism 18.
0 are interlocked and connected, and when the plowing depth by the rotary tillage device 3 changes, the cover 15 is displaced accordingly, and the displacement of the cover 15 causes the opening adjustment valve 14 to change.
A plowing depth control mechanism 21 is configured to automatically operate the lift arm cylinder 6 and automatically maintain the plowing depth set by the plowing depth setting lever 20.

The push-pull wire 19 is connected to the link mechanism 1
8, and when working with the plow device 22 installed, the plow device 22
The structure is such that it can be easily changed to a working mode in which the plowing depth is maintained constant (so-called draft control), which will be described in detail next.

That is, as shown in FIG. 3, a top link holder 24 is attached to the rear of the vehicle via a torsion bar 23.
At the same time, a plow device 22 is connected to the top link 2a and the lower links 2b, 2b instead of the tilling device 3, and the top link holder 24 and the opening adjustment valve 14 are connected to the rod 2.
5, which converts ground load fluctuations to the plow device 22 due to changes in plowing depth into displacements of the top link holder 24 in the front-rear direction, and thereby operates the opening adjustment valve 14 to open the plow. device 22
is configured to automatically maintain the plowing depth at a set depth.

In order to interlock and connect the rotary cover 15 and the opening adjustment valve 14, it is not limited to the push-pull wire 19 as described above, but also a bell crank, a link, a rod, etc., in a side view, the lower links 2b, 2b. The push-pull wire 19 may be provided in an overlapping manner on the pivot portions of the vehicle body side and the tilling device 3 side, respectively, so that the rotary cover 15 and the opening adjustment valve 14 are linked.
Alternatively, a mechanism consisting of a bell crank, a link, and a rod is collectively referred to as a mechanical linkage mechanism 19.

[Brief explanation of drawings]

The drawings show an embodiment of the riding type cultivator according to the present invention, in which Fig. 1 is a perspective view of the main parts, Fig. 2 is a schematic mechanical diagram of the tillage depth control mechanism shown together with the hydraulic circuit, and Fig. 3 is a diagram showing the structure during plowing. FIG. 3... Cultivation device, 6... Lift arm cylinder, 11... Control valve, 13... Return path, 14...
Opening adjustment valve, 15... Rotary cover, 19...
Mechanical linkage mechanism, push-pull wire, 21...
...Plowing depth control mechanism.

Claims (1)

[Scope of Claims] 1. A tilling device 3 is provided on the traveling vehicle body so that it can be raised and lowered via a single-acting lift arm cylinder 6, and a control valve 11 for raising and lowering is provided in the pressure oil supply path to the cylinder 6, The rotary cover 15 of the tilling device 3 is swingably provided, and the rotary cover 15
The cylinder 6 is configured to maintain the swing angle of the rotary cover 15 within a set range based on the displacement of the rotary cover 15.
A riding type cultivator is provided with a tillage depth control mechanism 21 that automatically operates the tillage depth control mechanism 21.
, the control valve 11 and the cylinder 6
A return passage 13 is connected to the pressure oil supply passage for releasing the supplied pressure oil with the control valve 11 in the upward operation position, and the return passage 13 is connected to the pressure oil supply passage.
An opening adjustment valve 14 is interposed in the opening adjustment valve 14.
and the rotary cover 15 are machined so that as the rotary cover 15 swings upward, the opening becomes smaller, and as the rotary cover 15 swings down, the opening becomes larger. A riding type cultivator characterized by being interlocked and connected via a type linkage mechanism 19. 2. The tiller according to claim 1, wherein the mechanical linkage mechanism is a push-pull wire 19.