JPH0718136B2 - Work machine height control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a device for controlling the height of an actuator such as an auger or a rotary pawl in a work machine such as a snow blower or an agricultural machine.

(Prior Art) FIG. 3 shows a conventional snow remover, in which a traveling body 2 provided with a crawler 1 is provided with a body b on which an engine or the like is mounted. On the other hand, it is rotatably supported around the support shaft 3.

An auger 4 is provided on the front side of the body b, and a shooter 6 is provided on a cover 5 that covers the auger 4. A handle 7 is provided on the rear side of the body b so that the operator can operate the handle while following the snow remover.

The support shaft 3 connecting and supporting the traveling body 2 and the body b is
The traveling body 2 is located slightly rearward of the center in the front-rear direction and maintains the balance of the center of rotation. That is,
When the handle 7 is released, the weight of the auger 4 exerts a moment in the direction in which the auger 4 comes into contact with the road surface.

Therefore, when the snow blower is not used, or when the auger 4 is traveling away from the road surface, the auger 4 must be held in the raised position.

Therefore, the fastener 8 is rotatably attached to the traveling body 2 and the elongated hole 9 is formed in the fastener 8. The body b is provided with a fastening means 10 including a bolt and a nut.

Therefore, force is applied to the handle 7 to lift the auger 4, and the fastening means 10 is fastened at the lifted position to hold the position.

(Problems to be Solved by the Present Invention) In the conventional working machine configured as described above, the fastening means 10 is maintained while the actuator such as the auger 4 is being lifted.
Since it is necessary to tighten the work, there is a problem that the operator is required to have an unnatural posture, which makes the work extremely difficult. Moreover, fastening means
The auger 4 cannot be kept at a predetermined height position unless 10 is strongly tightened, but for example, in the case of a woman, the tightening force is limited, so that the tightening means 10 cannot be strongly tightened. There were things. If the tightening force of the fastening means 10 is weak, the actuator may drop accidentally, which is very dangerous, but there is also a problem that this danger cannot be avoided.

It is an object of the present invention to provide a device that controls the height position of an actuator by using a control cylinder and eliminates the above-mentioned conventional drawbacks.

(Means for Solving Problems) In order to achieve the above object, the present invention provides a supporting member for an actuator such as an auger or a rotary claw in a working machine such as a snow blower or an agricultural machine, and the supporting member is used as a body. The control cylinder is provided between the support member and the body so as to be rotatable with respect to the main piston, and the control cylinder has a free piston inside the bottom side chamber defined by the main piston. Has
A buffer valve that exerts a damping force when the fluid in the rod side chamber flows to the bottom side chamber and a check valve that allows only the flow from the free piston side to the rod side chamber are provided in parallel, and the bottom side chamber and the rod side chamber are An operating check valve is provided in a passage communicating with a pump or the like.

(Operation of the present invention) Since the present invention is configured as described above, when the pressure fluid from the pump is supplied to the bottom side chamber, the main piston moves together with the free piston. The height position of the actuator of the working machine is determined.

In this state, for example, when the actuator rides on a convex portion of the road surface, the main piston moves in the direction away from the free piston, and the fluid in the rod side chamber at this time passes through the buffer valve to the free piston and the main piston. Flowing between.

Therefore, if the fluid in the rod-side chamber passes through the buffer valve as described above, its damping force is exerted, so that the shock when the actuator rides on the convex portion of the road surface is absorbed.

Further, when the main piston moves and the fluid in the rod side chamber flows between the free piston and the main piston as described above, the flow rate corresponding to the rod volume becomes insufficient between the two pistons. By that amount, negative pressure is generated between both pistons. Therefore, if the impact is alleviated, the main piston returns to the initial position in an attempt to correct this negative pressure. That is, the actuator
It will be returned to the positioned position.

(Effect of the present invention) According to the device of the present invention as described above, the pressure position of the fluid supplied to the cylinder is used to control the height position of the actuator of the working machine.
No manual operation is required, which makes positioning work easier.

Further, even if a shock is applied to the actuator while the working machine is running, the shock can be absorbed by the buffer valve provided in the main piston, so that the influence on the operator is reduced.

The control device of the present invention can naturally be used not only for snowplows and agricultural machines but also for industrial machines and the like.

(Example of the present invention) The example shown in Figs. 1 and 2 relates to a snow blower,
A traveling body 12 provided with a crawler 11 is equipped with a body b. The base end 13a of the support member 13 is attached to the body b.
Is rotatably attached, and an auger 14 as an actuator of the present invention is attached to the free end 13b of the support member 13.
Is attached.

The tip end of the piston rod 15 of the control cylinder S is rotatably attached at a substantially intermediate position between the base end 13a and the free end 13b of the support member 13.
The base end side of is rotatably attached to the body b.

A main piston 16 to which a piston rod 15 is connected is installed in the control cylinder S as described above, and the inside of the cylinder S is partitioned into a bottom side chamber 17 and a rod side chamber 18.

The main piston 16 is provided with a buffer valve 19. The buffer valve 19 allows the flow of fluid from the rod side chamber 18 to the bottom side chamber 17 and exerts a damping force when this flow occurs. .

A check valve 20 is also provided on the main piston 16, but the check valve 20 is configured to allow only the flow from the intermediate chamber 22 to the rod side chamber 18.

The bottom chamber 17 of the control cylinder S as described above is provided with a free piston 21 therein, and an intermediate chamber 22 is formed between the free piston 21 and the main piston 16.

The bottom side chamber 17 and the rod side chamber 18 of this control cylinder S
Each of which is connected to the pump P via the passages 23 and 24, and the operate check valve 2 is connected to the passages 23 and 24.
5 and 26 are connected. This operate check valve 25, 2
6 allows only the flow from the pump P to the control cylinder S in the normal state. However, when pressure is applied to the operating check valve 25 on the passage 24 side and to the operating check valve 26 on the passage 23 side, the check valve 25,
26 opens, allowing the flow from the control cylinder S to the pump P.

Then, the passages 27, 28 and 29, 30 communicating with the tank T are connected to the passages 23, 24, respectively.
Check valves 31 and 32 are connected to 27 and 28, and relief valves 33 and 34 are connected to the passages 29 and 30. The check valves 31 and 32 allow only the flow from the tank T to the passages 23 and 24.

Further, although a manual switching valve 35 is connected to the passages 23 and 24, the switching valve 35 connects both the bottom side chamber 17 and the rod side chamber 18 via a passage 36 depending on the switching position. , To communicate with the tank T.

Now, when the manual switching valve 35 is closed, the motor M is driven to operate the pump P, and, for example, the pressure fluid is supplied to the passage 23 side, this pressure fluid is guided to the bottom side chamber 17 and the passage 23 side. The pressure causes the operation check valve 26 to enter the free flow state. Therefore, the rod side chamber 18
The free piston 21 and the main piston 16 move to the right in the drawing while discharging the fluid in the passage 24. At this time, the fluid in the rod-side chamber 18 circulates to the pump P, and the circulated fluid is again supplied to the bottom-side chamber 17 via the passage 23. However, the flow rate discharged from the rod side chamber 18 becomes insufficient as compared with the flow rate supplied to the bottom side chamber 17 by the amount corresponding to the volume of the piston rod 15.
Therefore, this shortage is sucked from the tank T through the check valve 32.

Free piston 21 and main piston as above
When the control cylinder S and 16 move together in the right direction in the drawing, the control cylinder S extends. When the control cylinder S extends, the support member 13 rotates clockwise in FIG. 1 to raise the auger 14. When the auger 14 is raised to the desired height position in this way, the motor M is stopped and the discharge amount of the pump P is made zero.

Operate check valve 2 when the pump discharge is zero
Since 5, 26 are in the normal state, discharge of fluid from the bottom side chamber 17 and the rod side chamber 18 is prevented. Therefore, the main piston 16 holds its stop position and holds the auger 14 at the desired position.

When the pump P is rotated in the opposite direction from this state, the pressure fluid from the pump P passes through the passage 24 and the rod side chamber 18
And the pressure check on the side of the passage 24 brings the operating check valve 25 into a free flow state.

Therefore, if the pump P is rotated in the opposite direction to the above, the free piston 21 and the main piston 16 move leftward in the drawing, and the control cylinder S contracts. When the control cylinder S contracts in this manner, the support member 13 rotates counterclockwise in FIG. 1 to lower the auger 14.

When the control cylinder S contracts as described above, the fluid is discharged to the bottom side chamber 17 into the passage 23 and circulates to the pump P. The recirculated flow rate is again discharged from the pump P and supplied to the rod side chamber 18, but the flow rate discharged from the bottom side chamber 17 is equal to the volume increase of the bottom side chamber 18 by the rod volume. Will increase. Therefore, the increased flow rate is returned from the relief valve 34 to the tank T.

By controlling the motor M and specifying the rotation direction of the pump P as described above, the control cylinder S can be expanded / contracted according to the rotation direction.

Further, when the push-up force acts on the auger 14 with the free piston 21 and the main piston 16 of the control cylinder S positioned so that the auger 14 comes into contact with the road surface, the push-up force is applied by the buffer valve 19. Be absorbed. Then, after absorbing this thrusting force, the main piston 16 returns to the initial set position, and the principle thereof is as follows.

For example, the free piston 21 and the main piston 16 are the second
At the position shown in the figure, if a force in the direction of arrow 37, that is, a thrust force is applied to the cylinder S, the operating check valves 25 and 26 are in the normal state and are substantially closed. The fluid in 18 is the buffer valve 19
Via, into the intermediate chamber 22 between the two pistons 16, 21,
The free piston 21 and the main piston 16 are separated from each other.
When the fluid in the rod-side chamber 18 thus passes through the buffer valve 19, the buffer valve 19 exerts a damping force to absorb the thrust force.

However, with respect to the volume increase amount of the intermediate chamber 22 at this time, the flow rate flowing into the intermediate chamber 22 via the buffer valve 19 is likely to be insufficient by the amount corresponding to the volume of the piston rod 15,
The intermediate chamber 22 has a negative pressure. Therefore, when the thrust force is absorbed, the main piston 16 returns to the original position so as to correct the pressure difference between the intermediate chamber 22 and the rod side chamber 18. At this time, the fluid in the intermediate chamber 22 flows into the rod side chamber 18 via the check valve 20.

Therefore, when a force in the direction of arrow 37 acts on the piston rod 15, the thrusting force can be absorbed by the buffer valve 19 and the auger 14 can be slowly returned to the initial set position.

When the intermediate chamber 22 becomes negative pressure, the free piston 21
The cracking pressure of the operate check valve 25 must be set to a relatively high value so that the following does not follow the May piston 16. Because, if the cracking pressure of the operate check valve 25 is extremely low, when the main piston 16 moves in the direction of arrow 37, the free piston 21 follows the main piston 16 while sucking the fluid from the tank T, and the intermediate chamber This is because no negative pressure will be generated at 22.

Further, the free piston 21 is for preventing the fluid from passing through the check valve 20 and flowing out to the rod side chamber 18 when the pressure fluid is supplied to the bottom side chamber 17.

Further, when the pump P or the like fails, the manual valve 35 is opened, and the bottom side chamber 17 and the rod side chamber 18 are short-circuited and both are communicated with the tank T. In this way, the auger 14 can be manually raised and lowered.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention.
The figure is a schematic view of a main part, FIG. 2 is a hydraulic circuit diagram, and FIG. 3 is a front view of a conventional snow remover. b …… Body, 13 …… Supporting member, 14 …… Auger, S ……
Control cylinder, 16 ... Main piston, 17 ... Bottom side chamber, 18 ... Rod side chamber, 19 ... Buffer valve, 20 ... Check valve, 21 ... Free piston, 23,24 ... Passage, 25,26
...... Operate check valve, P ...... Pump.

Claims (1)

[Claims] 1. In a working machine such as a snow blower or an agricultural machine, a supporting member is provided on an actuator such as an auger or a rotary claw, the supporting member is rotatably provided with respect to the body, and the supporting member and the body are combined. A control cylinder is provided in between, and this control cylinder has a free piston inside the bottom side chamber defined by the main piston.
The main piston is provided with, in parallel, a buffer valve that exerts a damping force when the fluid in the rod side chamber flows to the bottom side chamber, and a check valve that allows only the flow from the free piston side to the rod side chamber in parallel. A height control device for a working machine in which an operating check valve is provided in a passage that connects the bottom side chamber and the rod side chamber to a pump or the like.