JPH0451532Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a drive control configuration of a hydraulic cylinder for controlling the plowing depth and angle of a working machine such as a rotary tiller attached to a tractor.

(b) Prior Art Conventionally, the technology of controlling the plowing depth and left/right inclination angle of a working implement attached to a tractor using a hydraulic cylinder is known.

For example, as in Japanese Utility Model Application Publication No. 52-55817.

(c) Problems to be solved by the invention However, in the conventional control device, a single-rod hydraulic cylinder is used as the hydraulic cylinder, and the same amount of oil is sent to the contraction side and the expansion side of the cylinder. Since the cylinder was being contracted and expanded, there was a problem in that the speeds were different between the contraction side and the expansion side.

Therefore, in both plowing depth control and angle control, there was a difference in control convergence between the reduction side and the extension side, and this appeared as a disturbance in the control state.

The present invention solves this problem.

(d) Means for solving the problem The purpose of the present invention is as described above. Next, the configuration for achieving the purpose will be explained.

In a configuration in which posture control is performed by raising and lowering a working machine using a single-rod hydraulic cylinder, the hydraulic valve is adjusted depending on the difference in operating speed due to the presence or absence of a rod on the contraction side and extension side of the single-rod hydraulic cylinder.
The ON time or OFF time is changed.

(E) Embodiment The purpose and structure of the present invention are as described above. Next, the structure of the embodiment shown in the attached drawings will be explained.

Figure 1 is a rear view of the left/right tilt control device for a rotary tiller, Figure 2 is a sectional view of the single-rod hydraulic cylinder for the control device in Figure 1, and Figure 3 is for controlling the solenoid of the electrohydraulic valve by ON time. Fig. 4 is a pulse diagram of the contraction side and extension side when the electrohydraulic valve is controlled by the OFF time. Fig. 5 is a hydraulic circuit diagram of the present invention. FIG. 6 is a plan view of the left-right tilt control device.

The overall configuration will be explained with reference to FIG.

The rotary tiller R is supported by one top link and two lower links, so when the tractor wheels move up and down according to the unevenness of the field, the rotary tiller R also follows the left and right tilting condition. I end up doing it.

The left/right tilt control device is configured to eliminate this problem. A tilt sensor S is provided on the top surface of the tilling cover of the rotary tiller R, and the tilt sensor S detects the tilt angle of the rotary tiller R. The inclination angle of the tilling device R is compared with the setting value by the setting device, and the single rod hydraulic cylinder interposed in the right lift link 6 is expanded or contracted in accordance with the comparison value.

Lift arms 4R, 4L and lower link 10
Left and right lift links 6 and 5 are interposed between R and 10L.

Next, FIG. 5 will be explained.

A hydraulic pump P is attached to the engine of the tractor, and the pressure oil discharged from the hydraulic pump P is divided by a flow divider D, one of which is a hydraulic valve for raising and lowering the lift arm 4, and the other is an external outlet. The oil is sent to an externally mounted working machine such as a front loader through the switching valve 15.

The other is supplied via the relief valve L to the electrohydraulic valve SV, which is the essential part of the present invention.
Pressure oil controlled by the electromagnetic hydraulic valve SV is sent to the single-rod hydraulic cylinder via check valves 7 and 8.

The electrohydraulic valve SV is provided with switching solenoids S1 and S2, and switching excitation of the solenoids S1 and S2 causes the electrohydraulic valve to switch.
SV is switched and pressure oil is checked at check valve 7,
8 to oil chamber A or B of single-rod hydraulic cylinder
The oil is sent to

Next, FIGS. 1 and 2 will be explained.

Of the left and right lift links 5 and 6 that support the rotary tillage device R, only the right lift link 6 is equipped with a single-rod hydraulic cylinder, and the oil chamber A on the extension side or the contraction side of the single-rod hydraulic cylinder is interposed in only the right lift link 6. Pressure oil is sent to either oil chamber B,
The piston 2 inside the hydraulic cylinder 1 moves up and down.

However, the piston 2 in the hydraulic cylinder 1 is provided with the rod 3 only on one side. Therefore, the extension side oil chamber A and the contraction side oil chamber B have different piston action areas and different volumes due to the presence of the rod 3, and when the same amount of oil is sent, the contraction side oil chamber B The rate of change of the cylinder is faster when oil is sent to the extension side oil chamber A, and the extension speed is slower when oil is sent to the extension side oil chamber A.

The difference in volume between the extension-side oil chamber A and the contraction-side oil chamber B directly affects the control, and the degree of convergence of the left-right tilt control differs between the left and right sides.

The ratio of the volume of the extension side oil chamber A to the volume of the contraction side oil chamber B is the same as the ratio of the working area of the piston 2. Therefore, if the working area on the extension side oil chamber A side is a, and the working area on the contracting oil chamber B side is b, then if the oil amount is fed at the ratio of a/b, the speed of expansion and contraction can be made the same. It can be done.

Figure 3 shows solenoids S1 and S2 energized ON.
By setting the time to the ratio a/b, the extension speed of the single-rod hydraulic cylinder is made the same.

That is, in the case of FIG. 3, when the solenoid on the oil feeding side is energized, the solenoid is not continuously excited, but the time during which the solenoid is excited is determined by a pulse signal. In the case of ON time control, the time during which the solenoid is energized is varied to obtain a constant ratio of oil volume, and the OFF time of the solenoid is kept constant.

In the case of this embodiment, if the ON time of solenoid S2 for sending oil to the contraction side oil chamber B is T1, and the ON time of solenoid S1 for sending oil to the extension side oil chamber A is T0, then T1 /T0=b/a.

The case shown in Fig. 4 is the same in that the solenoid of the electrohydraulic valve SV is energized by a pulse, but the 0N time of the pulse is the same.
The amount of oil is adjusted by changing the OFF time.

In the case of the OFF time control, the OFF time of solenoid S2 that sends oil to the contraction side oil chamber B is set as t1,
Solenoid S1 on the side that sends oil to the extension side oil chamber A
If OFF time is t0, t1/t0=a/b
It is constructed in inverse proportion.

As described above, when controlling using a single-rod hydraulic cylinder, the expansion and contraction times can be made the same for the extension side oil chamber A and the contraction side oil chamber B by changing the ON time and OFF time. It is.

In addition, since a single-rod hydraulic cylinder is interposed in the direction of lowering the rotary tilling device R, the weight of the rotary tilling device R may act on the cylinder, which may affect the expansion and contraction speed. When performing the left-right tilt control, the rotary tillage device R is supported on the field,
Since a state similar to that in which the rotary tiller R is supported by the tilled soil is obtained, the own weight has no effect.

Further, in this embodiment, the left-right tilt control device has been described, but the present invention can be similarly applied to a tillage device.

(f) Effects of the invention Since the invention is constructed as described above, it has the following effects.

In other words, single-rod hydraulic cylinders have been used in conventional work equipment control, but in this case, the operating speeds are different between the extension side and the contraction side, and this causes a difference in the elapsed time from the start of control to convergence. It was becoming more apparent. As a result, unevenness occurred in left and right control.

The cause of this is that it is a single rod, so it would be fine to use both rods, but due to the cylinder's oil-tight structure, support structure, etc.
Using both rods had a significant effect on increasing costs.

In the present invention, this problem can be easily corrected by simply modifying the control flowchart, and uniform control can be achieved.

[Brief explanation of the drawing]

Figure 1 is a rear view of the left/right tilt control device for a rotary tiller, Figure 2 is a sectional view of the single-rod hydraulic cylinder for the control device in Figure 1, and Figure 3 is for controlling the solenoid of the electrohydraulic valve by ON time. Fig. 4 is a pulse diagram of the contraction side and extension side when the electrohydraulic valve is controlled by the OFF time. Fig. 5 is a hydraulic circuit diagram of the present invention. FIG. 6 is a plan view of the left-right tilt control device. 1... Hydraulic cylinder, 2... Piston, 3...
...Rod, A...Extension side oil chamber, B...Reduction side oil chamber.

Claims (1)

[Scope of utility model registration request] In a configuration in which a single-rod hydraulic cylinder is used to raise and lower a work machine and control its posture, the hydraulic valve is operated according to the difference in operating speed due to the presence or absence of a rod on the contraction side and the extension side of the single-rod hydraulic cylinder.
An automatic control device for a tractor implement characterized by varying the ON time or OFF time.