JPS6367405A - Hydraulic control mechanism for elevating work machine - Google Patents

Abstract

PURPOSE:To prevent the noise of a hydraulic control valve and improve the durability thereof, by juxtaposing a flow-control solenoid valve in parallel with a solenoid valve for moving a work machine upward and a solenoid valve for moving out the machine downward, and connecting the flow-control solenoid valve to a flow-control valve for moving the work machine upward. CONSTITUTION:A flow-control solenoid valve (a) is juxtaposed in parallel with a solenoid valve (b) for moving a work machine upward and a solenoid valve (c) for moving the work machine downward which control the upward/downward motion of a work machine. The flow-control solenoid valve (a) is connected to a flow-control valve for moving work machine upward 4. Therefore, it is unnecessary to make the upward/downward motion of the work machine slow or quick in response to the change of duty ratio of pulse, so as to prevent the noise of a hydraulic control valve. Moreover, it is possible to automatically control the work machine not by means of pulse-drive but by means of ON-OFF control of solenoid valves, consequently for improving the durability of the hydraulic control valve.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial application field The present invention is a rice transplanter, a tractor, etc., in which a working machine is attached to the rear of the machine, which is a traveling device, through a mounting device, and a single-acting hydraulic This invention relates to a hydraulic control mechanism for lifting and lowering a working machine that is lifted and lowered by a cylinder.

(B) Prior Art Conventionally, in working machines attached to tractors, rice transplanters, etc., the lifting speed is slow when controlled by an automatic control device, and conversely, when turning around at the edge of the field, the lifting speed is set to be slow. The technique of changing the pulse width of a solenoid valve to obtain an optimum value is known.

For example, Japanese Patent Application Laid-Open No. 138303/1983.

(c) Problems to be Solved by the Invention The purpose of the present invention is to change the lifting speed using the conventional pulse width by high-speed continuous switching of the solenoid valve, thereby improving the reliability of the operation of the hydraulic control valve and improving the reliability of the operation of the hydraulic control valve. There were problems with the durability of the valve. The present invention aims to solve this problem.

That is, it is the same in that a solenoid valve is used, but instead of adjusting the flow rate by changing the pulse, a solenoid valve for adjusting the flow M is placed separately, and the solenoid valve is turned ON and OFF to quickly adjust the flow rate. This is a slow speed switch.

(d) Means for Solving the Problems The objects of the present invention are as described above, and the configuration for achieving the objects will now be explained.

In a hydraulic control valve for a lifting mechanism that raises and lowers a work machine using a single-acting hydraulic cylinder, a solenoid valve for raising and a solenoid valve for lowering C are configured as pilot valves to raise and lower the work machine.
At the same time, by arranging another flow control solenoid valve a and switching the flow control solenoid valve a, the raising flow control valve 4 in the raising circuit and the lowering flow control valve 7 in the lowering circuit can be operated at the same time. , it is possible to switch between the open side and the throttle side, and the lifting and lowering of the work equipment can be changed rapidly or slowly.

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

Fig. 1 is a drawing showing a flowchart of the control device of the present invention, Fig. 2 is a drawing showing the vertical movement of a float 9 of a rice transplanter as an example of a sensor of the control device, and Fig. 3 is a drawing showing the lifting and lowering of the working machine of the present invention. Fig. 4 is a diagram showing the operating states of three solenoid valves a-b-c, Fig. 5 is a plan view of the hydraulic control valve of the present invention, and Fig. 6 is a bottom view. , FIG. 7 is a cross-sectional view taken along line H-H in FIG. 16, FIG. 8 is a cross-sectional view taken along line B-B in FIG. 7, and FIG. 10 is a cross-sectional view taken along line - in Figure 12, Figure 11 is a cross-sectional view taken along line D-D in Figure 12, and Figure 12 is taken along line G- in Figure 7.
C cross-sectional view in the direction of arrows, FIG. 13 is a cross-sectional view of A-A in FIG. 7,
14 is a sectional view taken along the line EE in FIG. 12, FIG. 15 is a sectional view taken along the line FF in FIG. 11, and FIG. 16 is a left side view.

The working machine elevation control mechanism of the present invention will be explained with reference to FIGS. 1, 2, 3, and 4.

As an example in which the present invention is implemented in a rice transplanter, the sensor of the control device is installed on a float in the planting section, and the float 9
Depending on the rotation angle of the front end of the planter, the planting section, which is a working machine, can be switched between rapid and slow elevation. If the present invention is applied to a tractor, the rear cover of a rotary tiller or the like may be used as the sensor.

Next, at the inclination angle of the float, let vS be the level of the horizontal plane, which is the field surface. A dead zone level VS-VDS is provided above the horizontal level VS (actually, the position where the working machine has sunk and the tip of the float 9 has risen).

Further, a slow rise level ■P is provided above the unsteady zone level VS-VDS (the position where the work machine sinks and the float 9 rises). Similarly, a slow descending level VH is provided below the horizontal level ■S (the position where the work machine has risen and the float 9 has rotated downward).

Then, the detected value V■ from the sensor which is also used by the float 9, the horizontal level VS, the fuwazai level VS-VDS-
The flow control solenoid valve a, the raising solenoid valve b, and the lowering solenoid valve C are turned ON and OFF by comparing the slow speed increase level v p -fl with the speed decrease level VH.

In Figure 1, from the control start position, the planting part UP
Switch/planting part D OW N switch 0N-OFF
The determination is made based on the position of the detected value Vl.

First, when the planting section UP switch is ON, the flow control solenoid valve a is turned on, and the raising flow control valve 4 and the lowering flow control valve 7 are operated to the open side, and the raising solenoid valve is set ONL to unload. This closes valve 2. By this operation, pressure oil rapidly flows into the single-acting hydraulic cylinder, causing a rapid rise.

Next, when the planting section UP switch is OFF and the planting section DOWN switch is also OFF, the control outputs are output because they are in the neutral position. Both remain OFF.

Next, when the planting section UP switch is OFF and the planting section DOWN switch is ON, the flow control solenoid valve a is turned ON, and with the raising flow control valve 4 and the lowering flow control valve 7 open, the detected value When Vl>slow descent level VH, the lowering solenoid valve C is turned on, the lowering check valve 6 is opened, and rapid lowering is performed.

When slow descending level VH > detected value VI > horizontal level vS, lowering solenoid valve C is turned ON to open lowering check valve 6, flow control solenoid valve a is turned OFF, and raising flow control valve 4 and lowering check valve 6 are opened. The lowering flow control valve 7 is in a throttled state and is slowly lowered.

Horizontal level VS)l*output value Vl>fuwatai level 5-VD
In the case of S, the control output is stopped in order to maintain the neutral position.

In the case of fuwazai level VS-VDS>detected value vr>slow rise level vp, the raising solenoid valve 4 is turned on and the unloading valve 2 is closed, the flow control solenoid valve a is turned OFF, and the raising flow control valve 4 is turned on. The lowering flow control valve 7 is in a throttled state and the lowering flow control valve 7 is slowly raised.

When the slow speed increase level vp>detected value Vl, the raising solenoid valve is turned on, the unloading valve 2 is closed, and the flow control solenoid valve a is turned on.
The raising flow control valve 4 and the lowering flow control valve 7 are opened to allow a rapid rise.

As you can see from the above explanation, turn on the planting section UP switch.
In this case, it is often at the end of automatic control work such as turning around at the edge of the field, so for this operation, the flow control solenoid valve a should be turned OFF, and the raising flow control valve 4 and the lowering flow control valve 4 should be turned OFF. The flow control valve 7 is not in a throttled state, and only a rapid rise is performed.

On the other hand, in response to the operation of the planting section DOWN switch, the work equipment is not only lowered (it is in an automatic control state, but may also be raised depending on the situation). The section DOWN switch can also be called an automatic control switch.

Control according to the flowchart is repeatedly executed while being detected at intervals of several milliseconds.

Figure 4 shows the 0N-O of the flow control solenoid valve a, the lowering solenoid valve C, and the raising solenoid valve during rapid and slow ascending and descending.
The state of the FF is shown in an easy-to-understand manner, with O indicating the ON state of the solenoid valve and x indicating the OFF state of the solenoid valve.

In the flow control solenoid valve a, the ○ state indicates that the solenoid valve is ON, and the raising flow control valve 4 and the lowering flow control valve 7 are in an open state. × indicates that the solenoid valve is OFF, and the raising flow control valve 4 and the lowering flow control valve 7 are in a throttled state.

Next, the circuit diagram of the hydraulic control valve shown in FIG. 3 will be explained.

Inside the valve case (■) constituting the hydraulic control valve of the present invention, there is a pump boat P from the hydraulic pump, a tank boat T that is a boat for drain oil to the hydraulic oil tank, and a cylinder that is a boat for the single-acting hydraulic cylinder. It consists of three ports: port Cy.

Then, inside the valve case ■, when the relief valve 1° that protects the entire structure of the hydraulic control valve is closed, the unload valve 2° that sends pressure oil to the cylinder boat Cy is throttled by the raising flow control valve 4. Flocon relief valve 3 to discharge surplus oil to tank boat T. Raising Flocon relief valve 4 to throttle the oil amount in the rising circuit. Raising Flocon relief valve 4 which is placed between the Raising Flocon valve 4 and cylinder boat 070 to regulate the return of pressure oil. Check valve 5° Lowering check valve 6° Lowering check valve disposed between the check valve 5 and cylinder port 1-Cy, and opened when descending to discharge the pressure oil in the cylinder port Cy to the tank boat T. Pressure applied to the oil path 22 while connecting the oil path 22 and oil path 34 for hydraulically operating the lower flow control valve 7 and the up flow control valve 4 when the lowering flow control valve 7 is opened. It consists of a check valve 8° arranged in a direction that raises oil and does not act on the flow control valve 4.

Then, on the top surface of the valve case V, which has the above-mentioned valves inside, a flow control solenoid valve a, a solenoid valve for raising, and a solenoid valve for lowering C, which serve as pilot valves for operating each valve, are arranged. , the three solenoid valves are turned ON-OFF by a control signal based on the flowchart.

Next, each valve in the hydraulic control valve and the path of pressure oil will be explained based on the drawings from FIG. 7 to FIG. 16.

Pressure oil from the hydraulic pump is sent via piping to a pump boat P, which is clearly shown in FIG.

A pressure oil passage 21 extends from the pump port P, and the oil passage 41 of the relief valve 1, the unload valve 2, and the flow controller are connected to the core oil passage 21, as clearly shown in FIG. The pressure oil working surfaces of the relief valve 3 and the lifting flow control valve 4 are in communication with each other.

The oil passage for the relief valve 1 will be explained. pump bow)
As described above, the oil passage 41 communicates with the oil passage 21 of P, and pressure oil acts on the pressure oil acting surface of the valve body.

When the hydraulic pressure increases and the valve body moves against the spring, the pressure oil in the oil passage 21 passes through the oil passage 46 and the oil passage 30 to the tank port 1-
It is led to an oil passage 25 which is an oil passage to T. 13 is a relief pressure adjustment screw.

Next, the oil passage of the unload valve 2 will be explained. The pressure oil working surface of the spool of the unload valve 2 is connected to the pump bow 1-
The oil passage 20 which protrudes into the oil passage 21 of P and communicates with the lifting solenoid valve is open on the back chamber side biased by a spring. As shown in Fig. 15, the lifting solenoid valve is configured to move the internal poppet valve b1 forward and backward by the solenoids and springs on both sides of the valve, thereby opening the oil passage 20 and the oil passage 3 on the tank port side.
It opens and closes between 0 and 0. Solenoid valve for cough relief
When the FF is open and the back pressure in the back chamber of the unload valve 2 is released, the pressure in the oil passage 21 of the pump boat P overcomes the spring force, the unload valve 2 opens, and the pressure oil is released. The oil flows out from the oil passage 40 at the tip of the load valve 2 into the oil passage 25 of the tank boat T, and returns to the tank. Conversely, when the lifting solenoid valve is turned ON and moved to the closing side, the pressure in the back chamber of the unloading valve 2 becomes large, the unloading valve 2 is closed, and the pressure oil in the pump bow +-p is transferred to the lifting flow controller. It flows in the direction of valve 4 and causes the single-acting hydraulic cylinder to extend in the upward direction.

Next, let me explain about the flow control relief valve 3. 1st
This is clearly illustrated in FIG.

The flow control relief valve 3 is the throttle 1 of the lifting flow control valve 4.
It plays the role of releasing excess pressure oil to the tank port T according to the opening degree of 0, and after passing through the lifting flow control valve 4, it is placed on the back chamber side where the spring of the flow control relief valve 3 is installed. Pressure oil is supplied to four people through the oil passage 36. When communicating the oil passage in the back chamber of the flocon relief valve 3 from the core oil passage 36, a throttle 12 is provided to provide a damper effect between the switching of the raising flocon valve 4 and the switching of the flocon relief valve 3. A hole is inserted into the spool of the relief valve 3. Furthermore, the oil passage 21 of the pump boat P is opened at the pressure oil acting surface of the flow control relief valve 3, as described above.

Then, when the lifting float control valve 4 is switched to the throttle side for slow lifting, the hydraulic pressure applied to the pressure oil acting surface of the flow control relief valve 3 increases and is pushed against the spring, causing the oil in the tank boat T to This increases the amount of discharge into the passage 25. When the lifting float control valve 4 is switched to the open side for rapid lifting, the hydraulic pressure applied to the pressure oil acting surface of the flow control relief valve 3 and the back chamber becomes equal, but a spring is installed on the back chamber side. Therefore, the flow control relief valve 3 is in the closing direction. The amount of oil discharged from the tank boat T into the oil passage 25 is reduced.

Next, the oil passage of the lifting flow control valve 4 will be explained. This is clearly illustrated in FIG.

The pressure oil acting surface of the cough relief flow control valve 4 opens to the oil passage 21 of the pump boat P, and a spring is interposed on the back chamber side in the direction of pushing the cough relief flow control valve 4 toward the throttle side by the throttle 10. Pressure oil in the oil passage 21 is introduced via the throttle 11 in the direction of sliding toward the open side. The flow control solenoid valve is also constructed as shown in FIG. In the case of flow control, the flow control solenoid valve a is turned on, closing the oil passage 30 to the tank boat T, and the pressure oil from the throttle 11 pushes the raising flow control valve 4 against the spring toward the back chamber side, and the flow control valve a is turned on. 10
is opened to place the lifting flow control valve 4 in the open position, and the normal amount of pressurized oil flows into the oil path 26 to the lifting check valve 5 without passing through the throttle. In the case of reverse slow lifting, the flow control solenoid valve a is turned OFF and opened, so the pressure oil on the throttle 11 side flows from the oil path 22 to the tank boat T, and from the oil path 23 of the flow control solenoid valve a to the tank boat. The oil is discharged through the oil passage 23, transferred to the oil passage 30, guided to the oil passage 25 of the tank boat T, and returned to the tank. Therefore, the biasing force of the spring in the back chamber of the raising flow control valve 4 is stronger, and the flow control relief valve 3 is switched to the throttle position where the throttle 10 acts, resulting in slow upward and downward movement. In order to prevent back pressure from being generated in the back chamber where a spring is installed in the lifting flow control valve 4, the back chamber is connected to the oil passage 2 of the tank boat T.
5 are communicated with each other by oil passages 33 and 30.

Next, the oil passage configuration of the lift check valve 5 will be explained.

This is clearly illustrated in FIGS. 7, 9 and 10.

The pressure oil discharged from the lifting flow control valve 4 flows through the oil passage 26.
This leads to an oil chamber in the direction that pushes the lowering check valve 5, and this oil chamber also reaches the pressure oil working surface of the lowering check valve 6 via the oil passage 32.

A cylinder boat Cy leading to the single-acting hydraulic cylinder is opened in the oil passage 32. Piping is also connected to the cylinder boat Cy to guide pressure oil to the single-acting hydraulic cylinder.

Next, the oil passage for the lowering check valve 6 will be explained. 7, 9 and 14 are clearly illustrated.

A spring is interposed in the back chamber of the lowering check valve 6,
Further, the pressure oil in the oil passage 32 is guided in the direction of closing the lowering check valve 6 via the throttle 44, and the pressure oil is discharged from the oil passage 28 on the back chamber side to the oil passage 29 on the tank boat T side. It is closed by a lowering solenoid valve C. Lowering solenoid valve C
As shown in FIG. 12, the lifting solenoid valve b and the flow control solenoid valve a have the same structure and open and close between the oil passage 28 and the oil passage 29. The oil passage 28 is led from the back chamber of the lowering check valve 6 to the lowering solenoid valve C, and when the lowering solenoid valve C is turned on, the pressure oil in the back chamber of the lowering check valve 6 flows from the oil passage 28 to the lowering solenoid valve C. is discharged to the tank port) T via the oil passages 29 and 30, and the lowering check valve 6 opens, and the pressure oil in the single-acting hydraulic cylinder is transferred from the oil passage 32 to the oil passage 38 direction, that is, the lowering flow control valve. It is discharged in the direction of 7.

Next, the configuration of the lowering flow control valve 7 will be explained.

The lowering flow control valve 7 is clearly illustrated in FIGS. 13 and 14.

A spring is interposed in the back chamber of the lowering flow control valve 7, and the oil passage 38 on the discharge side of the lowering check valve 6 is opened at the pressure oil acting surface.

The lowering flow control valve 7 is opened and closed by switching the flow control solenoid valve a, similar to the above-mentioned raising flow control valve 4. A midway portion of the oil passage 22 between the float control solenoid valve a and the raising float control valve 4 communicates with the check valve 8 from a position before reaching the throttle 11 of the raising flow control valve 4. The check valve 8 is arranged in the direction '' so that the pressure oil from the oil passage 22 does not act on the lowering flow control valve 7. It is configured to communicate with the inside of the spool of the lowering flow control valve 7 via the oil passage 38 and the throttle 15, and to act on the side to open the lowering flow control valve 7.

Therefore, the flow control solenoid valve a is turned on and the oil passages 22 and 2 are closed.
3 is closed, the lowering flow control valve 7
Like the lifting flow control valve 4, it is opened in the direction in which the normal flow rate for rapid lifting flows, and the lowering check valve 6
The pressure oil discharged from the tank boat T passes through the land portion of the open throttle 14 and is transferred from the oil passage 39 to the oil passage 25 of the tank boat T.
The amount of oil that has not been squeezed out is discharged.

Then, when the flow control solenoid valve a is turned OFF and the space between the oil passage 22 and the oil passage 23 is opened, the pressure oil in the oil passage 38 escapes to the tank port T direction via the check valve 8, and the lowering flow control valve 7 is pushed by a spring and moves in the direction in which the throttle 14 acts, throttles the discharge flow rate from the oil passage 38 to the oil passage 39 of the tank port T, and slowly lowers the flow rate.

What actually switches the lowering flow control valve 7 is the pressure of the pressure oil discharged from the lowering check valve 6 toward the oil path 38, and when the lowering check valve 6 is closed, the flow control solenoid valve a is switched. Even if , the lowering flow control valve 7 cannot be switched.

A throttle 15 is interposed on the side where the lowering check valve 6 opens the lowering flow control valve 7 and acts in a direction to flow the normal flow rate. The structure is such that there is a gap between the switching to the open side and the switching to the open side. Reference numeral 17 denotes a throttle amount adjustment screw, which is used to change the opening amount of the throttle 14 depending on the degree of contact with the end of the lower flow control valve 7.

With the above configuration, when the flow control solenoid valve a is turned ON, the flow control valve 4 for raising and the flow control valve 7 for lowering have the normal flow rate, and perform rapid raising and lowering, and when it is turned OFF, the flow control valve 4 for raising and lowering the flow control valve 7 performs rapid lifting.
・No. 14 is activated, the flow rate is low, and the pump moves slowly up and down.

When the lifting solenoid valve is turned ON, the unloading valve 2 closes and pressure oil flows to the side where the working machine is to be lifted.

When the lowering solenoid valve C is turned ON, the lowering solenoid valve C is opened, the lowering check valve 6 is opened, the pressure oil of the single-acting hydraulic sealing is discharged to the tank boat T, and the work equipment is lowered. It is.

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

First, unlike conventional hydraulic control mechanisms for lifting and lowering work equipment, the rapid and slow lifting and lowering of work equipment is not performed by changing the duty ratio of pulses, so there is no need to drive the valve in pulses, and This makes it possible to eliminate noise from the hydraulic control valve that accompanies driving.

Second, because it is configured to perform automatic control by ON-OFF control of the solenoid valve without pulse drive, there is no need to use an expensive hydraulic control valve that can withstand pulse drive, and instead of using conventional solenoid valves and hydraulic pressure control valves. Since it can be configured with a control valve, the cost is low, the durability of the hydraulic control valve is improved, and accurate operation can be performed.

[Brief explanation of the drawing]

Fig. 1 is a drawing showing a flowchart of the control device of the present invention, Fig. 2 is a drawing showing the vertical movement of the float 9 of a rice transplanter, which is a sensor of the control device, and Fig. 3 is a drawing showing the vertical movement of the float 9 of the rice transplanter, which is a sensor of the control device. Circuit diagram of hydraulic control valve, Figure 4 shows three solenoid valves a.
5 is a plan view of the hydraulic control valve of the present invention, FIG. 6 is a bottom view, and FIG. 7 is a sectional view taken along line H-H in FIG. Figure 8 is B-B in Figure 7.
9 is a sectional view taken along the line C-C in FIG.
Figure 0 is a cross-sectional view of Figure 12, and Figure 11 is a cross-sectional view of Figure 12.
12 is a cross-sectional view taken along line G-C in FIG. 7, FIG. 13 is a Δ-A cross-sectional view shown in FIG. 7, and FIG.
The drawings are a cross-sectional view taken along the line E--E in FIG. 12, FIG. 15 is a cross-sectional view taken along the line F--F in FIG. 11, and FIG. 16 is a left side view. ■...Valve case a...Flocon solenoid valve b...Raising solenoid valve C...Lowering solenoid valve 1...Valve relief valve 2...Unloading valve 3 ...Flocon relief valve 4...Flocon valve for lifting 5...Upper check valve 6...Check valve for lowering 7...Floor control valve for lowering 8...Check valve application Person Kanzaki Kokyukoki Seisakusho Co., Ltd. Agent Patent Attorney Toshibe Yano Figure 5, Figure 4, Figure 6, Figure 8v! I Figure 9 Figure 10 Figure 16 Figure 15

Claims (1)

[Claims] In a hydraulic control valve for a lifting mechanism that raises and lowers a working machine using a single-acting hydraulic cylinder, the lifting and lowering of the working machine are operated by a raising solenoid valve b and a lowering solenoid valve c, which are configured as pilot valves, and an additional solenoid valve. A flow control solenoid valve a is arranged, and by switching the flow control solenoid valve a, the raising flow control valve 4 of the raising circuit and the lowering flow control valve 7 of the lowering circuit are simultaneously switched to the open side and the throttle side. , a hydraulic control mechanism for raising and lowering a working machine, characterized by being able to switch the raising and lowering of the working machine between rapid and slow speeds.