JPH0349131Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a positioning cylinder that is optimal for controlling the height of actuators such as augers and rotary claws in working machines such as snow blowers and agricultural machinery.

(Prior Art) Figures 3 and 4 show a conventional snow blower, in which a body b on which an engine, etc. is mounted is provided on a pedestal 2 on which a crawler 1 is provided. In contrast, it is rotatably supported around a support shaft 3.

An auger 4 is provided on the front side of the body b, and a shutter 6 is provided on a cover 5 that covers the auger 4. Further, a handle 7 is provided on the rear side of the body b, and a cylinder 8 for positioning is provided between the handle 7 and the pedestal 2.

The support shaft 3, which connects and supports the pedestal 2 and the body b, is located slightly rearward of the center of the pedestal 2 in the front-rear direction, and maintains the balance of its center of rotation. In other words, when the handle 7 is released, the weight of the auger 4 exerts a moment in the direction in which the auger 4 contacts the road surface.

Therefore, when the snow blower is not in use or when traveling with the auger 4 away from the road surface, the cylinder 8 is contracted and the auger 4 is removed.
hold in the raised position.

The circuit diagram shown in FIG. 4 controls this cylinder 8.

The bottom side chamber 9 and rod side chamber 10 of this cylinder 8 are connected to the pump P via passages 11 and 12, and to these passages 11 and 12 are connected operating check valves 13 and 14. . The operating check valves 13 and 14 only allow flow from the pump P to the cylinder 8 in a normal state. However, if pressure builds up on the passage 12 side for the operated check valve 13 and on the passage 11 side for the operated check valve 14,
The check valves 13 and 14 are opened, and the cylinder 8
Flow from the pump P to the pump P is also allowed.

A free piston 15 is installed inside the bottom side chamber 9 of the cylinder 8, and a main piston 16
A control room 17 is formed between the two.
The main piston 16 also includes a control chamber 17.
A check valve 18 that only allows oil to flow from the rod side chamber 10 to the control chamber 17, and a buffer valve 19 that generates a damping force when oil flows from the rod side chamber 10 to the control chamber 17 are provided.

When an external force acts on the cylinder 8 positioned at a predetermined position and the main piston 16 moves in the direction of the arrow, the hydraulic oil in the rod side chamber 10 flows into the control chamber 17 via the buffer valve 19. . When the oil in the rod side chamber 10 flows into the control chamber 17 in this manner, a predetermined damping force is generated to absorb the external force.

At this time, the amount of flow from the rod side chamber 10 to the control chamber 17 tends to be insufficient by the rod volume, so the control chamber 17 becomes under negative pressure. for that,
After the external force is absorbed, the pressure difference between the rod side chamber 10 and the control chamber 17 causes the main piston to
6 returns to the original position.

(Problems to be Solved by the Present Invention) The conventional cylinder as described above requires a control circuit to control it, so there is a problem that the installation space becomes large.

Also, a check valve 18 is installed inside the main piston 16.
Since a buffer valve 19 and a buffer valve 19 must be provided, there is a problem in that a plurality of configurations are required.

The object of this invention is to provide a positioning cylinder that does not require the above-mentioned control circuit and does not require a buffer valve or the like to be provided within the main piston.

(Means for Solving the Problems) In order to achieve the above object, this invention includes a main piston inside the cylinder, divides the inside of the cylinder into a bottom side chamber and a rod side chamber, and a piston in the bottom side chamber. The pressure-receiving area of the piston in the rod side chamber is made smaller by the cross-sectional area of the piston rod than the pressure-receiving area of The rod side chamber is in direct communication with the pressure accumulating mechanism through a communication passage, and a restriction is formed in the communication passage.

(Operation of the present invention) Since the present invention is constructed as described above, when the on-off valve is opened, the oil lock state is released and both the bottom side chamber and the rod side chamber communicate with the hydraulic chamber. Therefore, both chambers have the same pressure, but since the bottom side chamber has a larger pressure receiving area, the difference in area causes the main piston to move and the cylinder to extend. Then, when the cylinder is extended to a predetermined position, the on-off valve is closed.
When the on-off valve is closed in this way, the bottom side chamber becomes an oil lock state and the cylinder stops at that position.

Furthermore, when the cylinder is in the oil lock state, if an external force is applied in a direction that causes the cylinder to extend, the main piston moves in the above-mentioned direction of extension. Therefore, the oil in the rod side chamber flows into the hydraulic chamber via the communication passage, and the impact is absorbed by the throttle formed in the communication passage.

Moreover, when the main piston moves as described above, since the on-off valve is closed, the pressure in the bottom side chamber becomes slightly negative. Therefore, after the impact force is absorbed by the throttle, the pressure in the rod side chamber communicating with the hydraulic chamber becomes higher than the pressure in the bottom side chamber.
In this way, a pressure difference is generated between the two chambers, and this pressure difference causes the main piston to return to its original position.

(Effects of the present invention) According to the positioning cylinder of this invention, the piston can be moved using the pressure in the hydraulic chamber, and the movement position can be controlled by the on-off valve.
It does not require a control circuit like the conventional one. Therefore, the installation space can be reduced accordingly, and the overall device can be made smaller.

Moreover, since it is sufficient to form a throttle in the main piston, there is also the effect that the configuration can be simplified.

(Embodiment of the present invention) The embodiment shown in FIGS. 1 and 2 relates to a snow blower, in which a body b is mounted on a pedestal 21 on which a crawler 20 is provided. And in this body b,
The base end 22a of the support member 22 is rotatably attached, and the auger 23 is attached to the free end 22b of the support member 22.

The tip of the piston rod 24 of the cylinder S is rotatably attached to an approximately intermediate position between the base end 22a and the free end 22b of the support member 22, and the base end of the cylinder S is attached to the body b. It is attached so that it can rotate freely.

The cylinder S is composed of an inner cylinder 25 and an outer cylinder 26. A main piston 27 is housed in the inner cylinder 25, and the inside of the inner cylinder 25 is divided into a bottom side chamber 28 and a rod side chamber 29. .

The space formed between the inner cylinder 25 and the outer cylinder 26 is used as a communication path 30, and the inner cylinder 25
The rod side chamber 29 and the communication passage 30 are communicated through a throttle 31 formed at the tip of the rod 5.

Furthermore, an auxiliary tank T is provided on one side of the cylinder S, and a free piston 32 is installed inside this auxiliary tank T, and the inside of the auxiliary tank T is divided into a gas pressure chamber 33 and a hydraulic chamber 34. There is.

The hydraulic chamber 34 directly communicates with the communication passage 30 and also communicates with the bottom chamber 28 via an electromagnetic on-off valve 35 .

This electromagnetic opening/closing valve 35 normally blocks communication between the hydraulic chamber 34 and the bottom side chamber 28, but opens when an excitation current is applied to it, allowing the hydraulic chamber 34 and the bottom side chamber 28 to communicate with each other. .

In other words, the rod side chamber 29 is always in communication with the hydraulic chamber 34 via the throttle 31 and the communication passage 30, but the bottom side chamber 28 is communicated with the hydraulic chamber 34 only when the electromagnetic on-off valve 35 is opened. ing.

When the electromagnetic on-off valve 35 is closed, the bottom chamber 28 is in an oil-locked state, so the main piston 27 remains stopped.

When the electromagnetic on-off valve 35 is opened from the state illustrated above,
The pressure oil in the hydraulic chamber 34 flows into the bottom side chamber 28, but at this time, the bottom side chamber 28 and the rod side chamber 29 remain at the same pressure, so the main piston 27 receives the pressure in both chambers 28 and 29. Due to the area difference, it moves in the direction of arrow 36 and extends piston rod 24. In other words, the support member 22
Rotate clockwise in the figure to raise the auger 23. Then, when the auger 23 is raised to a desired position, the electromagnetic on-off valve 35 is closed. By closing the electromagnetic on-off valve 35, the bottom side chamber 28 is oil-locked, so that the auger 23 stops at its raised position.

When lowering the auger 23 again from this raised position, the solenoid on-off valve 35 is opened and the auger 23 is lowered again.
Apply an external force such as input to 3 to force it down. When the auger 23 is forcibly lowered in this way, the main piston 27 moves in the opposite direction to the arrow 36 and drains the hydraulic oil in the bottom side chamber 28 to the hydraulic chamber 34.
Return to side. When the hydraulic oil flows into the hydraulic chamber 34 in this manner, the free piston 32 moves accordingly, increasing the pressure within the gas pressure chamber 34.

At this time, the hydraulic oil in the hydraulic chamber 34 flows into the rod side chamber 29, but the rate of change in the volume of the rod side chamber is reduced by the volume of the piston rod 24 between the bottom side chamber and the rod side chamber. Relatively speaking, the amount of oil flowing into the hydraulic chamber 34 increases.

The position of the auger 23 is controlled by moving the main piston 27 as described above. For example, when the main piston 27 is in the position shown in FIG. As mentioned above, stop at and,
Assuming that the illustrated stop position is the working position of the auger 23 and that a thrusting force is applied to the auger 23 at that position, the cylinder S functions as follows.

That is, when the upward force acts on the auger 23 as described above, the main piston 27 moves in the direction of the arrow 36.
move in the direction. In this way, the main piston 27
When the rod moves in the direction of arrow 36, the hydraulic oil in the rod side chamber 29 flows into the hydraulic chamber 34 via the throttle 31 and the communication passage 30. When the hydraulic oil flows through the throttle 31 in this manner, a damping force corresponding to the diameter of the throttle 31 is generated, and the shock is absorbed.

At this time, since the electromagnetic on-off valve 35 is closed, the main piston 27 moves as described above, and the inside of the bottom side chamber 28 becomes negative pressure. However, since the rod side chamber 29 communicates with the hydraulic chamber 34, a pressure difference occurs between the two chambers 28 and 29. This pressure difference causes the main piston 27 to move toward the arrow 36.
It moves in the opposite direction and returns to its original position.

In the above embodiment, the throttle 31 was formed at the tip of the inner cylinder 25, but the throttle of this invention can be used in any direction within the communication passage 30, which is the passage process that communicates the rod side chamber and the hydraulic chamber. It may be provided at any location.

As described above, according to this embodiment, by opening the electromagnetic on-off valve 35, the auger 23 can be raised, and by closing the electromagnetic on-off valve 35, the auger 23 can be positioned. becomes possible. Moreover, in this positioned state,
When thrusting force is applied to the auger 23, the aperture 31
After absorbing the impact force completely, the auger 23 is returned to its original position.

In this case, there is no need for a special control circuit, and there is no need to provide the main piston 27 with a buffer valve, a check valve, or the like.

The auxiliary tank T of the above embodiment constitutes the pressure accumulating mechanism of this invention. In other words, when the pressure inside the hydraulic chamber 34 increases, the free piston 3
2 moves, the gas chamber 33 compresses and accumulates pressure, while keeping the overall volume constant. Therefore, this auxiliary tank T is equipped with a pressure accumulation mechanism and a volume compensation function.

[Brief explanation of drawings]

Figures 1 and 2 show an embodiment of this invention; Figure 1 is a partial view of the device in use, Figure 2 is a sectional view, and Figures 3 and 4 show a conventional snow blower. 3 is a side view, and FIG. 4 is a diagram of its control circuit. S...Cylinder, 27...Main piston, 2
8... Bottom side chamber, 29... Rod side chamber, 30...
...Communication path, 31...Aperture, 34...Hydraulic chamber, 35
...Solenoid on-off valve.

Claims (1)

[Scope of utility model registration request] A main piston is installed inside the cylinder, and the inside of this cylinder is divided into a bottom side chamber and a rod side chamber, and the pressure receiving area of the piston in the rod side chamber is made smaller by the cross-sectional area of the piston rod than the pressure receiving area of the piston in the bottom side chamber. Moreover, a pressure accumulating mechanism with a volume compensation function is provided separately from the cylinder, and the bottom side chamber and the hydraulic chamber of the pressure accumulating mechanism communicate with each other via an on-off valve, while the rod side chamber communicates with the pressure accumulating mechanism via a communication passage. A positioning cylinder that communicates directly with the cylinder and has a restriction formed in the communication path.