JPH017842Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is a hydraulic system for raising and lowering the reaping part of a combine harvester, a hydraulic system for raising and lowering the ground work equipment of an agricultural tractor, etc., and a cylinder port that communicates with a single-acting cylinder for raising and lowering working equipment. In the valve case, a pump port communicating with a pump for supplying fluid and a drain port for discharging fluid are formed.
A check valve that opens and closes the flow path to the cylinder port and is biased in the direction of closing the flow path by the back pressure of the cylinder, and a shift caused by the supply of pressure fluid from the pump port to the pilot chamber. a pilot piston that presses a check valve to open the cylinder port, and a sensor that detects the height of the working device above the ground;
and a spool that is switched and operated in accordance with the operation of a manual lifting operation lever, and the spool is pressed against the cylinder by pressing the check valve toward the flow path opening side with pressure fluid from the pump port. a first state in which the pump is operated to raise the working device; a second state in which the fluid supply from the pump port to the cylinder side is stopped to keep the cylinder inactive; and a second state in which the pressure fluid from the pump port is operated to the pilot and a third state in which the cylinder is supplied to the chamber and the cylinder port and the drain port are communicated to operate the cylinder to the lowering side of the working device, and further, the spool is moved by the lifting operation lever. The present invention relates to a fluid pressure device for a working machine, which is provided with a pusher that presses the pilot piston so as to operate the check valve to open the flow path in conjunction with switching to the third state.

In the fluid pressure system of this type of work equipment, when the engine is operating, the opening of the check valve necessary for lowering the work equipment is controlled by the pressure fluid supplied from the pump port to the pilot chamber. Although pilot pressure can be used to make operations easier, for example, when it is necessary to lower the work equipment while the engine is stopped, such as during maintenance work on the work equipment, Since the check valve can be manually pressed and opened freely via the pusher and pilot piston, there is no need to start the engine each time to drive the pump that supplies pressure fluid, and the work device can be used even when the engine is stopped. Although it has the advantage of being able to easily perform the lowering, it has the following drawbacks.

That is, conventionally, a support rod is integrally provided upright on the shaft portion of the spool that operates the valve inside the valve case and extends out of the valve case so as to be orthogonal to the axial direction of the spool. The pusher is attached to the support rod, and the pusher is configured to press the operating end of the pilot piston facing the outside of the valve case when the spool is moved to the third state.

Therefore, in the conventional device described above, the spool and the pusher are integrated, and therefore, when the spool is operated, the fluid pressure and operation reaction force that the pilot piston receives acts on the pusher and moves the spool through the support rod. This bending moment acts as a bending moment against
A strain occurs between the spool and the valve case,
The drawback was that the spool operation became difficult.

The present invention was devised in view of the above-mentioned circumstances, and aims to provide a fluid pressure device for a work machine that allows smooth operation of the spool without causing any twisting between the spool and the valve case. shall be.

The characteristic structure of the fluid pressure device for a work machine of the present invention, which has been made to achieve such an object, is the above-mentioned one, which includes a swing arm that swings around one axis in response to the operation of the lift operation lever. On its free end side, the operating force of the swinging arm is transmitted to the spool only in the operating direction of the spool, and the force from the swinging arm in a direction perpendicular to the operating direction does not act on the spool. engaged with the spool so that the swinging of the swinging arm and the operation of the spool are linked, and
The pusher is provided at a location on the swing arm that is spaced apart from the spool engagement location.

That is, the pusher and the spool for manually operating the check valve toward the flow path opening side transmit force to the spool in the operating direction, and strain may occur between the spool and the valve case. In order to prevent the spool from acting on the spool in a direction perpendicular to the operating direction of the spool, the spool is connected via a swinging arm that engages with the spool, so that the fluid pressure and operation applied from the pilot piston to the pusher is prevented. Even if reaction forces act on the swinging arm, these forces do not act as a bending moment on the spool that would cause the twisting, as in the case of conventional systems, so the spool can be operated easily and smoothly. This has resulted in the effect that the check valve can be manually operated easily and easily when the engine is stopped.

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

As shown in FIG. 1, a threshing device 1 and a control section 2
A single-acting hydraulic cylinder 6 is installed at the front of the machine A, which is equipped with a reaping unit B, which is equipped with a pulling device 3, a clipper-type reaping device 4, and a device 5 for conveying and supplying the harvested grain culm to the threshing device 1. Drive up and down freely through the
It constitutes a combine harvester, which is an example of a work machine.

Further, as shown in FIG. 2, a support bracket 8 is installed on the frame 7 of the reaping section B on the lateral outer side of the control section 2 of the reaping device 4, and a support bracket 8 is attached to the frame 7 of the reaping section B. A pair of left and right ground-type height detection sensors 9, 9 are provided, each swinging up and down using its front end as a fulcrum as the height changes (mowing height change). A mechanism 10 for automatically controlling the operation of the control valve V ₁ for the hydraulic cylinder 6 and a manual lifting/lowering operation lever 11 for the control valve V ₁ are provided so that the cutting height is maintained within a set range based on the mowing height. There is.

The automatic elevating control mechanism 10 is constructed as follows.

As shown in FIGS. 3 to 7, the mounting frame 12 of the control valve V ₁ supports inner and outer double shafts 13 and 14 that are relatively rotatable, and one end of the inner shaft 13 is provided with a shaft as described below. valve
Swing arm 16 linked to spool 15 of V ₁
is fixed so as to be able to swing together with the inner shaft 13 around the axis of the inner shaft 13, and an arm 17 fixed to the other end and interlocking brackets 18, 18 connected to the boss portions of the sensors 9, 9. and springs 20, 20 which are interlocked and connected via a release wire 19 and bias the sensors 9, 9 in the grounding direction, respectively, and the sensors 9, 9 swing upward and the release wire 19 is loosened. A spring 21 is provided which switches and operates the valve _V1 via the swing arm 16 to the raised state when the valve V1 is raised.

When the sensors 9, 9 are both in the swing position within the set range, the valve V ₁ is placed in the neutral position for raising and lowering the reaping section, and when the sensors 9, 9 both rise above the set value, the valve V ₁ is activated. The valve V1 is switched to the reaping section up state and is operated, and furthermore, when the sensors 9, 9 are both lowered by a set value or more, the valve _V1 is switched to the reaping section lowered state and operated.

Further, the automatic elevation control mechanism 10 has a linking hole 2 with a release wire 19 on the sensor 9 side.
By making holes 2 and 22 into elongated holes, the valve V ₁ is operated in the downward state even when either of the sensors 9, 9 is downward, and the valve V ₁ is operated only when both the sensors 9, 9 are upward. The device is configured to operate in a raised state.

The linkage structure between the lift operation lever 11 and the valve _V1 is constructed as follows.

The lever 11 and an arm 23 fixed to one end of the outer shaft 14 are interlocked and connected via a turnbuckle 24, and the release wire 19 is connected to the arm 23, and
A pair of notch grooves 25, 25 having a predetermined width in the circumferential direction are formed at the other end of the outer shaft 14 with a phase difference of 180° in the circumferential direction.
5, 25, a pin 26 attached to the inner shaft 13
This allows the switching operation of the valve V ₁ based on the vertical swing of the sensors 9, 9 within the range of the notched grooves 25, 25, and also allows the notched grooves 25, 25 to be operated by the lifting operation lever 11. The valve V ₁ is configured to be manually switched and operated in conjunction with a swinging operation of a width greater than or equal to the notch width.

The control valve _V1 includes a port P1 communicating with the cylinder ₆ , a pump port _P2 , a drain port _P3 , and left and right steering hydraulic cylinders (an example of a fluid pressure actuator) in the valve case 27. Parallel valve holes are formed that communicate and connect to a carryover port _P4 that can supply hydraulic pressure to the control valves _V2 of 28 and 28, and one of the valve holes has a connection to the cylinder port _P1. The check valve 29 is capable of opening and closing the flow path and is biased in the closing direction by the back pressure on the cylinder 6 side, and the check valve 29 is pressed by the shift accompanying the supply of pressure oil into the pilot chamber 30. and a pilot piston 31 for opening the flow path to the cylinder port _P1 , and both of these 2
A pressure oil supply and drainage passage 32 for the cylinder 6 is formed between the cylinders 9 and 31. In the other valve hole,
Notch groove 1 formed on the free end side of the swing arm 16
The spool 15 having a pin 33 that can be engaged and interlocked is slidably inserted into the spool 15, and the spool 15 has an oil passage 15a and an orifice that can communicate and connect the pump port _P3 and the pilot chamber 30. 15b, the pilot chamber 30 and the drain port _P3 , the pressure oil supply and drain passage 32 and the drain port
A first annular groove _15c that can be connected in communication with the pump port P3, a second annular groove 15d that can be connected in communication with the pump port _P3 and the pressure oil supply/drainage path ₃₂ , and the pump port P2 and the carrier port _P4 . The configuration is such that the following three states can be created by shifting the spool 15.

First state (reaping section raised) The check valve 29 is directly opened and operated by the pressure oil supplied from the pump port _P2 to the pressure oil supply/drainage path 32, and the cylinder 6 is operated to the reaping section upward side.

Second state (reaping section lifting/lowering stopped) The pilot chamber 30 and the drain port _P3 are communicated with each other, and the hydraulic pressure from the pump port _P2 is supplied to the carryover port _P4 to keep the cylinder 6 inactive. The steering hydraulic cylinders 28, 28 can be operated.

Third state (reaping part lowered) Pressure oil from the pump port _P2 is transferred to the oil passage 15a,
It is supplied to the pilot chamber 30 through the orifice 15b, and is also supplied to the carryover port _P4 , and communicates the cylinder port _P1 with the drain port _P3 , thereby operating the steering hydraulic cylinders 28, 28. The cylinder 6 is operated in the downward direction using the dead weight of the reaping part B while maintaining the possible state.

In the third state, the check valve 2
Since it is necessary to secure enough pilot pressure to open valve 9 against back pressure, a throttle valve 34 is interposed in the oil path from the carryover port _P4 to the steering control valve _V2 . .

The swing arm 16 and the pilot piston 31
A mechanical push mechanism 35 is provided between the spool 15 and the spool 15, which presses and opens the check valve 29 via the pilot piston 31 when the spool 15 is switched to the third state using the lift operation lever 11.

This push mechanism 35 includes the swing arm 16
A bolt for the pilot piston 31 is provided at a location away from the spool engagement interlocking portion, that is, at an intermediate portion between the connection location with the inner shaft 13 in the swing arm 16 and the notch groove 16a. A pusher 35a is screwed onto the pusher 35a so that its mounting position can be adjusted freely, and a locking nut 35b is screwed onto the pusher 35a.

Then, when it becomes necessary to lower the reaping section B under the condition that the engine that controls the drive of the hydraulic pump 36 is stopped, such as during maintenance work on the reaping section B, the lifting operation lever 11 is moved as described above. By operating the reaping part to the lowering operation position that brings about the third state, the check valve 29 is opened against the back pressure by the pusher 32a of the pusher mechanism 35 via the pilot piston 31, and the reaping part B descends under its own weight.

The pusher 35a is set so that the check valve 29 is at the minimum open position when the spool 15 reaches the stroke end in conjunction with switching to the third state.

In other words, when the hydraulic pump 36 is driven,
When the lift operation lever 11 is operated to the reaping section lowering operation position, the pilot piston 31 is pushed by pilot pressure before the pusher 35a is operated.

The spool 15 has a spool body 15 in which the oil passage 15a, orifice 15b, etc. are formed.
A and a linking part 15B having the pin 33, of which the linking part 15B is screwed and fixed to a female thread formed at the end of the oil passage 15a of the spool body 15A. With this configuration, there is no need for a plug to block the oil passage 15a, and the mounting position of the spool 15 can also be adjusted.

Note that although reference numerals are written in the claims section of the utility model registration for convenience of comparison with the drawings, the present invention is not limited to the structure of the attached drawings by such entry.

[Brief explanation of the drawing]

Figure 1 is a side view of the front part of the combine, Figure 2 is a diagram of the reaping section lifting/lowering control system, Figure 3 is a hydraulic circuit diagram, Figure 4 is
The figure is an enlarged sectional view of the valve mounting part, and Figure 5 is the 4th section.
FIG. 6 is an enlarged sectional view of the bulb, and FIG. 7 is a view taken along the line - in FIG. 6. 6... Cylinder, 11... Lifting operation lever, 1
5... Spool, 16... Swinging arm, 27...
Valve case, 29...Check valve, 30...Pilot chamber, 31...Pilot piston, 35
a... Pusher, P ₁ ... Cylinder port, P ₂
...Pump port, P ₃ ...Drain port.

Claims (1)

[Claims for Utility Model Registration] 1. Cylinder port P _{1 communicating with single-acting cylinder 6 for lifting and lowering working equipment, pump port P 2 communicating} with pump 36 for fluid supply, and drain port for discharging fluid. The cylinder port P 1 is located in the valve case 27 which is formed with the cylinder port P _{3 .}
A check valve 29 that opens and closes the flow path to the pump and is biased in the direction of closing the flow path by the back pressure of the cylinder 6, and a shift associated with the supply of pressure fluid from the pump port _P2 to the pilot chamber 30. The pilot piston 31 presses the check valve 29 to open the cylinder port _P1 , the detection result of the sensor 9 detects the height of the working device above the ground, and the lift operation lever 11 for manual operation. A spool 15 that is switched and operated in accordance with the operation is provided, and the spool 15 is used to press the check valve 29 toward the flow path opening side with pressure fluid from the pump port P ₂ to connect the cylinder 6 to the working device. A first state in which the pump is operated on the upward side; a second state in which fluid supply from the pump port _P2 to the cylinder 6 side is stopped to keep the cylinder 6 inactive; and a pressurized fluid from the pump port _P2. is supplied to the pilot chamber 30, and the cylinder port
A third valve that connects _P1 and the drain port _P3 to operate the cylinder 6 toward the lowering side of the working device.
It is configured so that it can be switched between the state and
The spool 1 is controlled by the lifting operation lever 11.
In the fluid pressure system of the work machine, the hydraulic pressure device is provided with a pusher 35a that presses the pilot piston 31 so as to operate the check valve 29 toward the flow path opening side in conjunction with the switching to the third state of the working machine. A swinging arm 1 that swings around one axis in response to the operation of a lift control lever 11
6, on its free end side, the operating force of the swinging arm 16 is transmitted to the spool 15 only in the operating direction of the spool 15, and the force from the swinging arm 16 in the direction perpendicular to the operating direction is The pusher 35 is engaged with the spool 15 so that the swinging of the swinging arm 16 and the operation of the spool 15 are linked so that the pusher 35 does not act on the spool 15. A fluid pressure device for a working machine, characterized in that it is provided at a location on the swing arm 16 that is spaced apart from the spool engagement location. 2. The fluid pressure device for a work machine according to claim 1, wherein the pusher 35a is screwed and fixed to the swing arm 16 in a state where the mounting position can be adjusted.