JP2003148417A - Hydraulic control cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic control cylinder, capable of constructing check valves of a plurality of relief passages of a simple structure with a small number of parts, and facilitating machining to inexpensively provide the valves. SOLUTION: This hydraulic control cylinder has a cylinder body 6a, both ends of which are closed and having an oil pressure passage communicated with both end parts, a piston 6b inserted in the cylinder body 6a to reciprocate, and a piston rod 6c fixed to the piston 6b and led through one end side of the cylinder body 6a to go in and out. A plurality of relief passages 9, 9 are provided for communicating between oil pressure chambers a, b on both end sides of the cylinder body partitioned by the piston 6b, and the relief passages 9, 9 are provided with a check valve 20. The check valve 20 has one valve element 20a common to all of the relief passages 9, 9 to thereby open and close all of the relief passages 9, 9 at the same time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control cylinder mainly used for controlling shell opening / closing operation of a single rope type grab bucket.

[0002]

2. Description of the Related Art Generally, the operation of a hydraulic control cylinder,
Single rope grab buckets that open and close shells by crane lifting and hanging operations are widely used. As shown in FIG. 6, this conventional single rope type grab bucket 1 comprises a pair of shells 2 and 2 that are configured to be grabs and are opened and closed to face each other, and a pivotal center of the rotation center of each shell 2 and 2. The lower frame 3 that has been made to be located, the upper side of the lower frame 3, and the rear surfaces of the shells 2 and 2 and the suspension arms 4, 4 ...
To the upper frame 5 connected via the intermediate movable frame 7 between the upper and lower frames and connected to the lower frame 3 via the hydraulic control cylinder A (shown in FIG. 7). On the other hand, the operation of the hydraulic control cylinder A and the wire rope 8 for suspending and closing the grab which is fixed to the lower end and is wound around pulleys provided on the intermediate movable frame 7 and the upper frame 5 and extended upward. And a hydraulic valve control block B (shown in FIG. 8) for controlling the.

The hydraulic valve control block B is connected to both ends of the hydraulic control cylinder A and includes a pilot type check valve which is switched between a state in which only one-way flow is allowed and a state in which two-way flow is allowed. It constitutes a hydraulic control channel.

In this single rope type grab bucket, the lower frame 3 is moved in the middle by operating the hydraulic control means with the shell shown in FIG. 6 closed and lifted to operate the hydraulic control cylinder A in a free state. The frame 7 becomes free, and the weights of the lower frame 3 and the shell 2 cause the lower frame 3 to descend and the shells 2 and 2 to open, as shown in FIG.

In this state, the crane is operated to move the grab bucket onto the desired grip and lower it. Then, when the wire rope 8 is lowered with the shells 2 and 2 placed on the grasped object (landing state), the upper frame 5
On the other hand, the intermediate movable frame 7 becomes free, and the intermediate movable frame 7 descends toward the lower frame 3 and at the same time the piston rod 6 of the hydraulic control cylinder A is moved.
c is pushed into the cylinder body 6a.

When the intermediate movable frame 7 is lowered to a predetermined position in this way, the hydraulic valve control block B automatically disables the hydraulic control cylinder A.
In this state, the wire rope 8 is lifted by a crane to move the intermediate movable frame 7 toward the upper frame 5, the shells 2 and 2 are closed, the grasped object is grasped in the shell, and the state shown in FIG. 6 is obtained. Be hung up.

The conventional hydraulic control cylinder A used in the single rope type grab bucket which operates in this manner is shown in FIG.
As shown in Fig. 7, a plurality of escape passages 9 are formed in the piston 6b sliding in the cylinder body 6a on the circumference around the connecting portion of the piston rod 6c so as to penetrate the piston 6b. Check valves 10 that operate individually are provided in the flow passages 9, and when the intermediate movable frame 7 described above moves (falls) toward the lower frame 3 due to its own weight, each relief flow passage 9 is opened. The intermediate movable frame 7 is smoothly lowered even at high speed.

As shown in FIG. 9, each check valve 10 is provided with a valve seat 10a in the relief flow passage 9 and a valve body 10b which opposes the valve seat 10a constitutes a relief flow passage and a valve chamber 10c. A structure is used in which the valve body 10b is inserted into the inside and is biased toward the valve seat 10a by the coil spring 10d.

[0009]

In the conventional hydraulic control cylinder as described above, since the precise check valve is individually provided in the relief passage provided in the piston, the valve seat, the valve body and the oil passage are precisely provided. Since it is necessary to machine in this way, and more than one escape passage is required, it is necessary to install check valves individually by that number, the number of parts is large, many precision machining is required, and the machining cost is high. There is a problem in that the device becomes bulky and the entire device becomes expensive.

In view of the situation of the prior art as described above, the present invention can construct a check valve having a plurality of escape passages with a simple structure and a small number of parts, and can be easily processed and provided at a low cost. For the purpose of providing.

[0011]

The features of the present invention for solving the above-mentioned conventional problems and achieving the intended purpose are as follows.
A cylinder body with both ends closed and hydraulic passages communicating with the both ends, a piston reciprocally inserted into the cylinder body, and a piston fixed to the piston and capable of moving in and out on one end side of the cylinder body Between the hydraulic chambers on both end sides of the cylinder body partitioned by the piston into a piston rod and a hydraulic control flow path communicating between the hydraulic chambers on both end sides of the cylinder body. A plurality of relief passages communicating with each other are provided, a check valve is provided in the relief passage, and the hydraulic control passage is switched between a state in which only one direction flow is allowed and a state in which both directions flow is permitted. In the hydraulic control cylinder having a pilot type check valve, the check valve is configured such that all the release passages are simultaneously opened / closed by a single valve body common to all the release passages. Lies in that it has.

It should be noted that the ends of the plurality of escape passages are opened in an annular arrangement centered on the piston rod connected to the piston, the open ends serve as valve seats, and the outer periphery of the piston rod has its axial direction. It is preferable that the check valve is configured such that one movably ring-shaped valve body is fitted and the valve body opens and closes the plurality of escape passages.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a hydraulic control cylinder according to the present invention will be described with reference to FIGS.
The same parts as those in the conventional example described above are designated by the same reference numerals, and duplicate description will be omitted.

This hydraulic control cylinder is used for the single rope type grab bucket shown in FIGS. 6 and 7 as in the prior art described above, and FIG. 1 shows the hydraulic control cylinder A and the hydraulic control cylinder A according to the present invention. FIG. 3 is a hydraulic circuit diagram showing a schematic configuration of a hydraulic valve control block B that constitutes a hydraulic control flow path.

The hydraulic control cylinder A includes a cylinder body 6a, a piston 6b reciprocally inserted into the cylinder body 6a, and a piston 6b fixed at the center position thereof to one end side of the cylinder body 6a. And a piston rod 6c led out so that the piston 6
In b, a plurality of escape passages 9, 9 for communicating between the hydraulic chambers on both end sides of the cylinder body partitioned by the piston 6b, that is, the piston head side hydraulic chamber a and the rod side hydraulic chamber b are communicated. Is equipped with.

As shown in FIGS. 2 to 5, the escape channels 9, 9 ... Are installed in an annular arrangement centered on the piston rod 6c, and the opening end on the rod side hydraulic chamber side serves as a valve seat. There is. Each of the escape passages 9, 9 ... Has a valve seat at the periphery of its open end, and is closed simultaneously by a single common check valve 20 that reciprocates in opposition to this. There is.

The check valve 20 is composed of a valve body 20a formed in an annular shape and a spring 20b for urging the valve body 20a for urging it toward the flow path opening side, that is, the valve seat side. A guide shaft portion projecting in the center of the end surface, that is, the outer circumference of the guide shaft portion 22 which is also used as the piston rod 6c in this embodiment, is fitted movably in the axial direction, and the back surface thereof is a coil spring. Two
Pressing with 0b.

At the end of the guide shaft portion 22, there is provided a valve body stopping portion 23 formed by increasing the diameter, and the stroke in the opening direction of the valve body 20a is restricted by this.

Although not shown, the spring 20b may be omitted if the delay of the operation of the valve body 20a at the time of shifting from the open state to the closed state does not cause a problem.

The hydraulic control cylinder constructed as described above is used for a single rope grab bucket as in the above-mentioned conventional example, and the internal pressure of the piston head side hydraulic chamber a is increased by applying an external force in the axial direction to the piston 6b. Rod side hydraulic chamber b
When it becomes higher, the hydraulic oil flows from the relief passage 9 to the same b side from the hydraulic chamber a, and the piston 6b is smoothly moved to the piston head side. On the contrary, when the internal pressure of the piston head side hydraulic chamber a becomes lower than that of the rod side hydraulic chamber b, the valve body 20a is pressed against the valve seat side by the internal pressure of the hydraulic chamber a and the escape passage 9
Is closed, and the flow of hydraulic oil through the escape passage 9 is blocked.

As shown in FIG. 1, the hydraulic valve control block B constituting the hydraulic control flow path of the hydraulic control cylinder A has a hydraulic control flow path 7 at both ends of the cylinder body 6a via connection flow paths 11 and 11. The hydraulic control flow path 7 is provided with a throttle valve 12 and a pilot check valve 13.

This pilot type check valve 13 is normally structured so that the flow from the upper end side to the lower end side of the cylinder body 6a is blocked and flows freely in the opposite direction. The hydraulic pressure is made to act through the opening / closing valve 14 formed of a valve. When the opening / closing valve 14 is opened and the hydraulic pressure is made to act on the pilot port, the non-return state is released, and any direction in the hydraulic control passage 7 It has a structure that does not block the flow of.

Therefore, by operating the opening / closing valve 14 from the closed state of the pilot flow passage 15 shown in FIG. 1 to the open state in the shell closed state shown in FIG.
The non-returned state of the check valve 13 is released, the hydraulic pressure control flow path 7 is opened, and the upward movement of the piston 6b becomes possible. The throttle valve 12 controls the flow rate at that time and controls the operating speed of the piston.

In the above-mentioned embodiment, the example in which the piston rod is connected to only one side of the piston has been described, but the piston rod may be connected to both the front and rear faces. Further, in the above-described embodiment, the check valve is provided on the end surface of the piston on the piston rod side, but it may be provided on the end surface on the piston head side.

[0025]

As described above, in the hydraulic control cylinder according to the present invention, both ends are closed, and a cylinder body having hydraulic passages communicating with the both ends is reciprocally inserted into the cylinder body. A piston, a piston rod fixed to the piston and led out to one end side of the cylinder body so as to be able to move in and out, and a hydraulic control flow path communicating between both hydraulic chambers on both end sides of the cylinder body, The piston is provided with a plurality of relief passages communicating between the hydraulic chambers on both ends of the cylinder body partitioned by the pistons, the relief passage is provided with a check valve, and the hydraulic control passage is unidirectionally provided. In a hydraulic control cylinder comprising a pilot type check valve that is switched between a state in which only flow is allowed and a state in which bidirectional flow is allowed, the check valve is
Since all the escape channels are configured to be opened and closed at the same time by using a single valve element common to all the escape channels, the structure of the escape channels can be simplified, so that the processing cost can be suppressed. In addition, the number of man-hours for processing the precise check valve body is reduced, and the hydraulic control cylinder can be manufactured at low cost. Further, since the valve body constituting the check valve opens and closes the escape passages collectively, the number of failures is reduced and the repair is facilitated.

In addition to the above-mentioned invention, the end portions of the plurality of escape passages are opened in an annular arrangement centered on the piston rod connected to the piston, the open end portions serve as valve seats, and the outer circumference of the piston rod is increased. The valve body is configured such that the valve body is fitted with a ring-shaped valve body movably in the axial direction, and the check valve is configured to open and close the plurality of escape passages with the valve body. Since it slides along the rod, the check valve can obtain smoother operation.

Further, since the piston rod is provided with the valve body stopping portion for regulating the moving length of the valve body in the opening direction with respect to the valve seat, the opening portion in the state where the check valve is opened is regulated,
It is possible to restrict the rapid flow of oil between the hydraulic chambers, and to suppress the operating speed of the hydraulic control cylinder.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of a hydraulic circuit of a hydraulic control cylinder according to the present invention.

FIG. 2 is a sectional view showing a main part of a hydraulic control cylinder according to the present invention.

3 is a cross-sectional view taken along the line AA in FIG.

FIG. 4 is a sectional view taken along line BB of the above.

FIG. 5 is a sectional view showing a closed state of the above check valve.

FIG. 6 is a front view showing a state in which the shell of the single rope type grab bucket is closed.

FIG. 7 is a front view showing a state in which the glove of the above-described single rope type grab bucket is opened.

FIG. 8 is a sectional view showing an outline of a conventional hydraulic cylinder.

FIG. 9 is a cross-sectional view showing a main part of a conventional hydraulic control cylinder.

[Explanation of symbols]

A hydraulic control cylinder B Hydraulic valve control block a Piston head side hydraulic chamber b Rod side hydraulic chamber 6a Cylinder body 6b piston 6c piston rod 7 Control hydraulic flow path 9 Escape channel 11 connection channels 12 Throttle valve 13 Pilot type check valve 13a Pilot port 14 Pilot valve 15 Pilot channel 20 Check valve 20a valve body 20b spring 22 Guide shaft 23 Valve stop

Claims (3)

[Claims] 1. A cylinder body having both ends closed and hydraulic passages communicating with the both ends, a piston reciprocally inserted in the cylinder body, and a cylinder body fixed to the piston. The cylinder main body has both ends of the cylinder body, which has a piston rod led out to and from one end, and a hydraulic control flow path communicating between the hydraulic chambers on both ends of the cylinder body, and which is partitioned by the piston into the piston. A plurality of relief passages communicating between the hydraulic chambers, a check valve provided in the relief passages, and a state in which only one direction flow is permitted in the hydraulic control passage and a state in which both directions are permitted. In a hydraulic control cylinder provided with a pilot type check valve that is switched between and, the check valve simultaneously opens and closes all the escape passages with a single valve element common to all the escape passages. A hydraulic control cylinder characterized by being configured as follows. 2. An end portion of a plurality of escape passages is opened in an annular arrangement centered on a piston rod connected to a piston, the opening end portions serve as valve seats, and the piston rod has an axial direction on the outer periphery thereof. 2. The hydraulic control cylinder according to claim 1, wherein a check valve is configured so that a movably ring-shaped valve body is fitted to the valve body, and the valve body opens and closes the plurality of escape passages. 3. The hydraulic control cylinder according to claim 2, wherein the piston rod is provided with a valve body stopping portion that regulates a moving length of the valve body in the opening direction with respect to the valve seat.