JP2502527Y2 - Hydraulic actuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a hydraulic actuating device characterized by a release valve mechanism for releasing pressure oil.

(Prior Art) A cutter utilizing hydraulic pressure has been developed that is convenient to carry and easy to handle in order to cut reinforcing bars, metal pipes, etc. at a construction site. In addition, a portable hydraulically-operated puncher for making a hole in an iron 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 that utilize such hydraulic pressure include a hydraulic operating device as an operating mechanism.

As this hydraulic operating device, a pump mechanism for pumping the oil in the oil tank is provided in the casing body provided with the oil tank,
By sending pressure oil from this pump mechanism into the cylinder,
A piston head slidably arranged in the cylinder is slid, and a piston rod connected to the piston head is linearly moved to perform cutting work by a cutting blade attached to the tip of the piston rod. Hydraulically operated cutter (for example, U.S. Pat. No. 3,733,699) or a hydraulically operated cutter as an improved device (Jitsuko 63-46069)
No.) is known.

The hydraulically operated cutter described in Japanese Utility Model Publication No. 63-46069 was filed by the applicant of the present application.The hydraulically operated device in this hydraulically operated cutter is such that the release valve mechanism for releasing pressure oil is a piston head. It is arranged in a concentric position.

FIG. 10 is a sectional view showing this release valve mechanism. This release valve mechanism is projected from the inner wall of the cylinder 20,
It has a protruding member (hereinafter referred to as “guide bar”) 26 that extends until it is inserted into the internal space 21a of the piston head 21. This guide bar 26 has a cylinder 20
Is provided with a through hole 26a penetrating the inner wall of the. The through hole 26a of the guide bar 26 is closed by the valve body 1 of the release valve. That is, the valve body 1 has an outer diameter larger than that of the tip portion of the guide bar 26, and can close the through hole 26a in close contact with the tip portion. A rod 2 extending in the axial direction is connected to the valve body 1, and a release valve is mounted by slidably inserting the rod 2 into the through hole 26a. The rod 2 has a shape in which a part of a circular cross section is shaved off, and the working oil flows through a gap between the shaved off part and the inner wall of the through hole 26a.

Inside the through hole 26a, a spring 29 that contacts the back surface of the valve body 1 (the surface on the side that closes the through hole 26a) is disposed.
Is urged in a direction away from the tip of the guide bar 26. A plate 3 that closes the internal space 21a is fixed to the inlet end of the internal space 21a of the piston head 21. The guide bar 26 is slidably inserted into the plate 3, and the valve body 1 is attached to the piston head 21.
When it comes to its advanced end position, its rear surface can come into contact with this plate 3. Further, a spring 4 is fixed to the back surface of the valve body 1 so that when the piston head 21 reaches its forward end position, it is compressed between the back surface of the valve body 1 and the plate 3.

The plate 3 is provided with a through hole 5 that connects the inside of the cylinder 20a and the internal space 21a of the piston head 21.
The pressure oil supplied to the inside 20a of the cylinder through this through hole 5 is sent to the internal space 21a and acts on the head of the valve body 1,
The valve body 1 is pressed against the tip of the guide bar 26.

(Problems to be Solved by the Invention) In such a conventional release valve mechanism, when the piston head 21 reaches its forward end position, the valve element 1 is separated from the tip end portion of the guide bar 26 and the through hole 26a is formed. The closed state is opened and the pressure oil in the cylinder 20a is released through the through hole 26a. This is done as follows. That is, as shown in FIG. 10, when the piston head 21 reaches its forward end position, the back surface of the valve body 1 contacts the plate 3 and the spring 4 fixed to the back surface of the valve body 1 It is compressed with the plate 3. Disc 1
Tries to separate from the tip portion of the guide bar 26 by the elastic force of the spring 4 and the urging force of the spring 29. At this time, the internal space 21 passes through the through hole 5 of the plate 3.
Since the pressure oil introduced into a acts on the valve element 1, the elastic force of the springs 4, 29 is reduced by the pressing force of this pressure oil. Therefore, the valve body 1 is a guide bar.
There were problems that it became difficult to separate from the tip of 26, the hydraulic release action could not be performed quickly, and the spring 4 had to be strengthened.

The present invention has been made in consideration of such a point, and provides a hydraulic actuating device equipped with a release valve mechanism capable of reliably performing pressure oil releasing action and downsizing the device. The purpose is to provide.

[Constitution of device]

(Means for Solving the Problems) In order to solve the above problems, the present invention comprises a plate fixed to the inlet end of the internal space of a piston head and a guide bar slidably inserted through the plate. It is characterized in that the gap is formed inside the outer shape of the valve body that abuts on the tip of the guide bar.

(Operation) According to the present invention, when the piston head comes to the forward end position thereof, the pressure oil supplied through the gap between the guide bar and the plate acts on the back surface of the valve body, and the valve body is operated by the pressure oil. Forcibly disengage from the tip of the guide bar. This ensures that the pressure oil is released through the through hole of the guide bar.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view showing an embodiment of the hydraulically actuated device according to the present invention, which is applied to a portable hydraulically actuated cutter.

In the figure, reference numeral 11 is a motor, and the motor shaft 12 is attached to the casing body 13 in a state of being inserted into the casing body 13. An oil tank 14 for storing oil is provided in the casing body 13, and a pump mechanism 15 for pumping the oil in the oil tank 14 is further arranged. Pump mechanism 15
Is the cam portion 16 formed on the motor shaft 12 and the cam portion 16
The piston 17 is reciprocally moved by a needle bearing, and an opening / closing valve 18 is arranged in the oil passage. The opening / closing valve 18 normally closes the oil passage with a spring 19. Reference numeral 20 is a cylinder,
It is connected to the casing body 13. A piston head 21 is slidably arranged in the cylinder 20, and a piston rod 22 is integrally connected to the piston head 21 with their respective axes aligned. The cylinder 20 has an oil tank
An oil passage 23 that communicates between 14 and the inside of the cylinder 20a is bored,
The oil passage 23 is closed by the opening / closing valve 18 as described above. In addition, the piston head 21 has
An oil release passage communicating with the oil tank 14 outside the cylinder is provided, 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 guide bar 26 is provided so as to be inserted into 1a so as to project from the inner wall of the cylinder 20 in the axial direction. Guide bar
A through hole 26a penetrating the inner wall of the cylinder 20 is formed in the cylinder 26 in the axial direction. A plate 31 is fixedly provided at the inlet end of the internal space 21a of the piston head 21 so as to close the internal space 21a. The guide bar 26 is slidably inserted into the plate 31 with a gap 30.

The oil release passage is formed through the through hole 26 of the guide bar 26 described above.
and a gap formed between the plate 31 and the guide bar 26.

The release valve mechanism 25 has a release valve that closes the through hole 26a of the guide bar 26 to open and close this oil release passage. FIG. 2 is a partially enlarged view of FIG. 1 showing the release valve mechanism 25. Release valve is guide bar 26
Flange portion 27a that abuts the tip of the and closes the through hole 26a
And a valve body 27 having a head portion 27b that abuts the innermost wall surface of the piston head 21 forming the internal space 21a, and the valve body 2
7, a rod 28 fixedly provided on the rear surface side of the flange portion 27a and slidably inserted into the through hole 26a of the guide bar 26.

The outer peripheral shape of the flange portion 27a of the valve body 27 is larger than the outer peripheral shape of the tip end portion of the guide bar 26. Also,
The rod 28 has a shape in which a part of a circular cross section is shaved off, and release oil flows through a gap 28a between the shaved portion and the inner wall of the through hole 26a. Guide bar
In the through hole 26a of the valve 26, a spring 29 that contacts the back surface of the flange portion 27a of the valve element 27 is arranged, and the valve element 27 is guided by the guide bar.
It is biased away from the tip of 26.

Gap 30 formed between the guide bar 26 and the plate 31
Are provided at two locations in the vertical direction, for example, as shown in FIG. The gap 30 has a size large enough to realize the oil release from the inside 20a of the cylinder, which is necessary for the piston head 21 to move backward. , Flange portion 27 of valve body 27
It is formed so as to be located inside the outer shape of a.

A spring 33 is arranged between the surface of the piston head 21 on the piston rod 22 side (the back surface of the piston head) and the jaw-shaped casing 32. Further, reference numeral 34 is a cutting blade attached to the tip of the piston rod 22.

Next, referring to FIGS. 4 and 5, the operation of the present embodiment having such a configuration will be described. First of all
As shown in the figure, the piston head 21 is positioned at the innermost end of the cylinder 20 to drive the motor 11 and rotationally drive the motor shaft 12. As a result, the cam 16 rotates, the piston 17 is reciprocated, and the oil in the oil tank 14 is pressure-fed 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, passes through the oil passage 23, and moves in the cylinder 20.
sent to a. The pressure oil sent into the cylinder 20a is
It acts on the flange surface of the piston head 21, and moves the piston head 21 to the right in FIG. As a result, the piston rod 22 also moves to the right, and the cutting blade 34 cuts the reinforcing bar or the like.

While the piston head 21 is moving to the right in the cylinder 20a, the valve body 27 contacts the tip surface of the guide bar 26 by the hydraulic pressure of the pressure oil flowing into the internal space 21a through the gap 30 to open the oil release passage. The constituting through hole 26a and the gap 30 are cut off from each other. The plate 31 fixed to the piston head 21 slides along the guide bar 26 in the axial direction.

When the piston head 21 moves to its forward end position, that is, as shown in FIG. 4, the guide bar 26 and the plate 31 move relative to each other, and the flange portion 27a of the valve body 27 is located at the tip of the guide bar 26. Upon contact, the gap 30 is closed by the flange portion 27a. At this time, the pressure oil inside the cylinder 20a acts on the back surface of the flange portion 27a, and the pressure for separating the valve body 27 from the tip portion of the guide bar 26 acts. This pressure and the force applied by the urging force of the spring 29 become larger than the pressing force by the hydraulic pressure that has pressed the valve body 27 until then, and the valve body 27 is momentarily separated from the tip end portion of the guide bar 26. As a result, the through hole 26a and the gap 30 communicate with each other, and the oil release passage is opened. The pressure oil in the cylinder 20a flows through the gap 30 to the through hole 26a, 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 is stopped, and the cutting action by the cutting blade 34 is Complete. After the piston head 21 stops, it is pushed back to the left in FIG. 1 by the spring 33. During this time the valve body
The spring 27 is held in a state of being separated from the tip end surface of the guide bar 26 by the spring 29, the oil release passage is opened, and the backward movement of the piston head 21 is quickly performed.

In this backward movement, the head 27b of the valve body 27 is moved to the piston head 2
It is stopped by being pushed by the innermost wall of the internal space 21a in 1 and coming into contact with the tip end portion of the guide bar 26 again. The piston head 21 is returned to the position shown in FIG. 1, and one step of the hydraulic operating system according to this embodiment is completed.

As described above, according to the present embodiment, when the valve body 27 performs the opening operation (release passage opening operation), the pressure oil in the cylinder 20a acts on the flange portion 27a of the valve body, and the valve body 27 is guided by the guide bar. It exerts the force to disengage from the tip of 26. Therefore, the pressing force of the pressure oil, which has conventionally been acting as a force for maintaining the valve body 27 in the closed state, can be used as a force for opening the valve body 27, and the opening operation of the valve body 27 can be further performed. It can be done smoothly. In addition, since the pressing force of the pressure oil is used for the opening operation of the valve body 27, the spring of the prior art is not required, and the structure of the release valve mechanism 25 can be made smaller and simpler.

FIGS. 6 to 8 show other shapes of the gap formed between the guide bar 26 and the plate 31. In FIG. 6, one gap 30a is provided.
In FIG. 7, three gaps 30b are provided, and in FIG. 8, four gaps 30c are provided. These gaps 30a, 30b, 30c are the piston head 21
Has a cross-sectional area sufficient to secure the amount of release oil required to realize the return movement of the valve body 27, and is provided inside the outer diameter of the flange portion 27a of the valve body 27. In addition to this, for example, a uniform gap may be provided between the guide bar 26 and the plate 31.

In this embodiment, the structure in which the flange portion 27a of the valve body 27 abuts the plate 31 has been described.
The opening operation of the valve body 27 may be performed immediately before the contact of 27a with the plate 31. Further, as a supplementary structure, a spring may be fixed to the flange portion 27a as in the conventional case.

Further, in the present embodiment, an example in which the piston rod 22 is connected to the piston head 21 with its axis aligned is shown. However, as shown in FIG. 9, the piston rod 22 is aligned with the axis of the piston head 21. It can also be applied to the case where they are connected to eccentric positions. 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 locking the piston rod 22 is not provided, and for example, a strong rotational force acts from the outside. In the case of hydraulically actuated devices, this is preferred.

Further, although the example in which the guide bar 26 is provided at a position that coincides with the axis of the piston rod 22 is shown, it may be provided at an eccentric position that does not coincide with the axis of the piston rod 22.

[Effect of device]

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

The hydraulically actuated device according to the present invention is particularly effective when used in a portable hydraulically actuated cutter, hydraulically actuated puncher or the like.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of a hydraulic actuator according to the present invention, FIG. 2 is a sectional view showing an example of a release valve mechanism according to the present invention, and FIG. 3 is a sectional view taken along line III-III in FIG. FIGS. 4 and 5 are sectional views showing the operation of the release valve mechanism according to the present invention, and FIGS. 6 to 8 are sectional views showing various forms of the clearance provided between the guide bar and the plate. Figure equivalent,
FIG. 9 is a partial sectional view showing another embodiment of the present invention, and FIG. 10 is a sectional view showing a release valve mechanism formed in a conventional hydraulic operating device. 20 …… Cylinder, 20a …… Inside cylinder, 21 …… Piston head, 21a …… Internal space, 25 …… Release valve mechanism, 26
...... Projecting member (guide bar), 26a …… Through hole, 27 ……
Valve body, 30 ... gap, 31 ... plate.

Claims (1)

(57) [Scope of utility model registration request] 1. A cylinder according to claim 1, wherein a release valve mechanism for releasing pressure oil sent into a cylinder for advancing a piston head arranged in the cylinder is inserted into an internal space of the piston head. A projecting member having a through hole penetrating through the inner wall of the cylinder and projecting from the inner wall of the projecting member, and having an outer shape larger than the tip of the projecting member and closely contacting the tip of the projecting member to close the through hole of the projecting member. In a hydraulic operating device including a valve body, a plate closing the internal space is fixedly provided at an inlet end of the internal space of the piston head, and the protruding member is slidable with respect to the plate. And a gap formed so as to be positioned inside the outer shape of the valve body.