JP2558971Y2 - Hydraulic actuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention] (Industrial application field) The present invention relates to a hydraulic operating device characterized by a release valve mechanism that releases pressure oil.

(Prior Art) A cutter using hydraulic pressure, which is portable and easy to handle, has been developed to cut a reinforcing bar, a metal pipe, or the like at a building site. Also, a portable hydraulically-operated puncher for punching a steel plate, a portable hydraulically-operated bending machine for bending a reinforcing bar, a metal pipe, and the like have been developed.

Various hydraulic processing devices utilizing such hydraulic pressure include a hydraulic operating device as an operating mechanism.

As the hydraulic operating device, a pump mechanism for pumping oil in the oil tank is provided in a casing body provided with the oil tank,
The pressure oil from this pump mechanism is sent into the cylinder,
The cutting operation is performed by the cutting blade mounted on the tip of the piston rod by sliding the piston head slidably disposed in the cylinder and linearly moving the piston rod connected to the piston head. A hydraulically-operated cutter (for example, U.S. Pat. No. 3,733,699) or a hydraulically-operated cutter as an improved device thereof (Japanese Utility Model Application No.
No.) are known.

In the hydraulically operated cutter described in Japanese Utility Model Application Laid-Open No. 60-66411, a release valve mechanism for releasing hydraulic oil is disposed concentrically with the piston head.

FIG. 6 is a sectional view showing the release valve mechanism. The cylinder 20 is provided with an oil supply passage 23 for supplying pressure oil to the cylinder interior 20a and an oil release passage 26 for releasing pressure oil from the interior 20a. Inside 20a of cylinder 20
, A piston head 21 is disposed slidably in the axial direction, and a piston rod 22 is integrally connected to the piston head 21 with their respective axes aligned. An internal space 21a is formed inside the piston head 21 from the hydraulic working surface of the piston head 21 in the axial direction of the piston rod 22, and a plate 3 for closing the internal space 21a is fixed to an inlet end of the internal space 21a. Have been. In addition, internal space 21a
Inside, a cylindrical slide valve 1 is slidably disposed in the axial direction. The sliding valve 1 is configured so that the plate 3 is inserted with a gap 5 therebetween, and one end of the sliding valve 1 can contact the inner wall surface of the cylinder 20 so as to surround the oil release passage 26. A stop ring 2 is fixed near the other end, and a kick spring 4 is attached to the outer periphery of the slide valve 1 using the stop ring 2.
Is installed. A recess 1a is formed on the side of the sliding valve that contacts the inner wall surface of the cylinder, and a spring 29 is mounted in the recess 1a.

In the figure, reference numeral 32 denotes a jaw-shaped casing that slidably holds the piston rod 22, and a spring 33 is provided between the jaw-shaped casing 32 and the piston head 21.

(Problem to be Solved by the Invention) In the release valve mechanism of the conventional hydraulic operating device having such a configuration, when the piston head 21 comes to its forward end position, the sliding valve 1 moves the inner wall surface of the cylinder 20. From the oil release passage 26 to release the closed state of the oil release passage 26 and release the pressure oil in the cylinder interior 20a through the oil release passage 26, which is performed as follows.
That is, when the piston head 21 reaches its forward end position, the kick spring 4 mounted on the slide valve 1 is compressed between the kick spring 4 and the plate 3. The sliding valve 1 attempts to separate from the inner wall surface of the cylinder 20 by the elastic force of the kick spring 4 and the urging force of the spring 29. At this time, the sliding valve 1 passes through the gap 5 between the plate 3 and the sliding valve 1. Interior space
Since the pressure oil introduced into 21a acts on the distal end surface of the slide valve 1, the elastic force of the springs 4, 29 is reduced by the pressing force of the pressure oil. For this reason, the sliding valve 1 becomes difficult to separate from the inner wall surface of the cylinder 20, and there have been problems that the hydraulic release operation cannot be performed quickly and that the kick spring 4 must be strengthened.

The present invention has been made in view of such a point, and a hydraulic actuating device having a release valve mechanism capable of reliably releasing the pressure oil and reducing the size of the device is provided. The purpose is to provide.

[Structure of device]

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a plate fixed to an inlet end of an internal space of a piston head and a sliding valve which slidably passes through the plate. The gap between the rod-shaped rod portion and the plate is formed so as to be located inside the outer shape of the flange portion of the sliding valve.

According to the present invention, when the piston head comes to its forward end position, the pressure oil supplied through the gap between the rod-shaped rod portion of the sliding valve and the plate acts on the back surface of the valve element, The body is forced away from the tip of the guide bar by pressure oil. This ensures that the pressure oil is released through the oil release passage.

(Example) Hereinafter, an example of the present invention is described with reference to drawings. FIG. 1 is a side sectional view showing an embodiment of the hydraulic operating device of the present invention, showing an example applied to a portable hydraulic operating cutter.

In the figure, reference numeral 11 denotes a motor, which is attached to the casing main body 13 with the motor shaft 12 inserted into the casing main body 13. An oil tank 14 for storing oil is provided in the casing body 13, and a pump mechanism 15 for pumping oil in the oil tank 14 is provided. Pump mechanism 15
Is a cam portion 16 formed on the motor shaft 12 and the cam portion 16
The piston 17 is reciprocated via a needle bearing, and an opening / closing valve 18 disposed in the oil passage. The opening / closing valve 18 normally closes the oil passage by a spring 19. Reference numeral 20 denotes a cylinder,
It is connected to the casing body 13. A piston head 21 is slidably disposed in the cylinder 20, and a piston rod 22 is integrally connected to the piston head 21 with their respective axes aligned. Oil tank on cylinder 20
An oil supply passage 23 communicating between the cylinder 14 and the inside 20a of the cylinder is provided, and the oil supply passage 23 is closed by the on-off valve 18 as described above. The piston head 21 is provided with an oil release passage 26 that communicates the inside 20a of the cylinder with the oil tank 14 outside the cylinder, and can be opened and closed by a release valve mechanism 25.

Inside the piston head 21, an internal space 21a is formed in the axial direction of the piston rod 22.
A sliding valve 27 is provided in 1a so as to be slidable in the axial direction. The sliding valve 27 has a rod-shaped rod portion 27a and a flange portion 27b provided at an end of the rod portion 27a, and has a concave portion at the other end of the rod portion 27a on the side that contacts the inner wall surface of the cylinder 20. Place 27c
Are formed. The other end of the rod 27a can be brought into contact with the inner wall surface of the cylinder 20 so as to surround the oil release passage 26, and a spring 29 is mounted in the recess 27c.

At the inlet end of the internal space 21a of the piston head 21, a plate 31 is fixed so as to close the internal space 21a. The rod portion 27a of the sliding valve 27 is
Is slidably communicated with a gap 30.

FIG. 2 is a partially enlarged view of FIG. 1 showing the release valve mechanism 25. FIG. 3 is a partial sectional view taken along the line III-III in FIG. As shown in FIGS. 2 and 3, the inner diameter portion of the plate 31 has a shape in which a part is cut off, and a gap 30 is formed between the inner diameter portion of the plate 31 and the outer circumference of the rod portion 27a of the sliding valve 27.
Are formed. The gap 30 is formed such that its maximum radial outward position is located inside the outer shape of the flange portion 27b of the slide valve 27.

A spring 33 is disposed between the surface of the piston head 21 on the piston rod 22 side (the rear surface of the piston head) and the jaw-shaped casing 32. Reference numeral 34 denotes a cutting blade attached to the tip of the piston rod 22.

Next, the operation of this embodiment having such a configuration will be described with reference to FIGS. First,
As shown in the figure, the motor 11 is driven while the piston head 21 is positioned at the innermost end of the cylinder 20, and the motor shaft 12 is driven to rotate. As a result, the cam 16 rotates, causing the piston 17 to reciprocate, thereby pumping the oil in the oil tank 14 toward the oil passage 23.
The pressure oil generated by the pump mechanism 15 pushes up the on-off valve 18 against the spring 19 and passes through the oil passage 23 to the inside of the cylinder.
Sent to 20a. The pressure oil fed into the cylinder interior 20a acts on the flange surface of the piston head 21 to move the piston head 21 rightward in FIG. As a result, the piston rod 22 also moves to the right, and the cutting blade 34 cuts a reinforcing bar or the like. Piston head 21 inside cylinder
While moving 20a to the right, the sliding valve 27 is pressed by the oil pressure of the pressure oil flowing into the internal space 21a of the piston head 21 through the gap 30, and the other end (flange portion 27b
End of the cylinder 20 abuts against the inner wall surface of the cylinder 20 to close the oil release passage 26. Further, the plate 31 fixed to the piston head 21 slides in the axial direction together with the piston head 21 along the rod portion 27a.

When the piston head 21 has moved to its forward end position, that is, as shown in FIG. 4, the rod portion 27a of the sliding valve 27 and the plate 31 relatively move, and the flange portion 27b of the sliding valve 27 Upon contact with 31, the gap 30 is closed by the flange portion 27b, and the supply of the pressure oil into the internal space 21a is stopped. At this time, on the back of the flange portion 27b,
The pressure oil in the cylinder interior 20a acts, and a pressure acts to separate the slide valve 27 from the plate 31. This pressure and the force obtained by adding the urging force of the spring 29 become larger than the pressing force by the hydraulic pressure that was pressing the sliding valve 27 until then.
The sliding valve 27 momentarily moves away from the plate 31 and the inner wall surface of the cylinder 20 (FIG. 5). This allows the oil release passage 26
Is released. The pressure oil inside the cylinder 20a flows outside the cylinder 20 through the oil release passage 26, the pressure difference on both sides of the flange surface of the piston head 21 is eliminated, the forward movement of the piston head 21 stops, and the cutting blade 34 The cutting action by is completed. After stopping, the piston head 21 is subsequently pushed back by the spring 33 to the left in FIG. During this time, the slide valve 27 is kept separated from the inner wall surface of the cylinder 20 by the spring 29, the oil release passage 26 is opened,
The backward movement of the piston head 21 is performed quickly.

In this backward movement, the tip of the flange portion 27b of the sliding valve 27 is pushed by the innermost wall of the internal space 21a in the piston head 21, and the other end of the sliding valve 27 again contacts the inner wall surface of the cylinder 20. Stop by touching. The piston head 21 returns to the position shown in FIG. 1, and one step of the hydraulic operating device according to the present embodiment ends.

Thus, according to the present embodiment, when the sliding valve 27 performs the opening operation (release passage opening operation), the cylinder internal 20a
Pressure oil acts on the flange portion 27b of the sliding valve,
To the cylinder 20 from the inner wall surface. For this reason, the pressing force of the pressure oil, which conventionally worked as a force for maintaining the sliding valve 27 in the closed state, can be used as a force for opening the sliding valve 27, and the opening of the sliding valve 27 can be performed. The operation can be performed more smoothly. In addition, since the pressing force of the pressure oil is used for the opening operation of the sliding valve 27, the structure of the release valve mechanism 25 can be made smaller and simpler without the need for a conventional spring.

Note that, in the present embodiment, an example in which the piston rod 22 is connected to the piston head 21 so that the axis thereof is aligned with the piston head 21 has been described. It can also be applied when If the piston rod 22 is connected to an eccentric position, the piston head 21 and the piston rod 22 do not rotate even if a key for preventing rotation is not provided on the piston rod 22, for example, a strong rotational force is applied from the outside. A hydraulic actuator is preferred.

The sliding valve 27 and the internal space 21a are connected to the piston rod 2
Although an example is shown in which it is disposed at a position coinciding with the axis 2 of FIG. 2, it may be disposed at an eccentric position that does not coincide with the axis of the piston rod 22.

[Effect of the invention]

As described above, according to the present invention, since the pressure oil is used for the opening operation of the release valve, the release operation of the release valve can be quickly and reliably performed, and the release valve mechanism can be downsized and simplified. can do.

The hydraulic actuator according to the present invention has a particularly excellent effect when used in a portable hydraulic cutter, a hydraulic puncher and the like.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of a hydraulic operating device according to the present invention, FIG. 2 is a partial sectional view showing an example of a release valve mechanism according to the present invention, and FIG. 3 is a sectional view taken along the line III-III of FIG. FIGS. 4, 5 and 6 are sectional views showing the operation of the release valve mechanism according to the present invention, and FIG. 6 is a sectional view showing a release valve mechanism in a conventional hydraulic operating device. 20: Cylinder, 20a: Inside the cylinder, 21: Piston head, 21a: Internal space, 23: Oil supply passage, 25:
... release valve mechanism, 26 ... oil release passage, 27 ... sliding valve, 27a ... rod portion, 27b ... flange portion, 30 ... gap, 31 ... plate.

Claims (1)

(57) [Scope of request for utility model registration] 1. A cylinder having an oil supply passage for supplying oil into the cylinder and an oil release passage for releasing oil outside the cylinder, and is disposed in the cylinder so as to be slidable in the axial direction. A slider for opening and closing an oil release passage of the cylinder having a piston head having an inner space formed in the axial direction and a rod-shaped rod portion slidably disposed in the inner space of the piston head in the axial direction. A valve for closing the internal space at an inlet end of the internal space of the piston head, and the sliding valve is integrally provided at an end of the rod-shaped rod portion. And the rod-shaped rod portion is slidably inserted into the plate with a gap, and the gap is inside the outer shape of the flange portion of the slide valve. A hydraulic actuating device, wherein the hydraulic actuator is located so as to be able to close the gap by a flange portion of the sliding valve.