JPS58113673A - Counterbalance valve - Google Patents

Abstract

PURPOSE:To prevent hunting without complicated work by providing an adjusting screw having a flow path in an orifice portion of a pilot circuit to provide a fine gap between an orifice and the adjusting screw for substantially reducing the orifice diameter. CONSTITUTION:When pressurized oil is supplied from the port 37 side, a portion of the pressurized oil is introduced into a chamber 36 as pilot pressure to urge a spool 15 rightward and open a return circuit of a counterbalance valve 6 so that the cylinder head side return oil returns to a tank from a port 19. Then, an orifice 38 in an orifice plate 13 has the bore reduced substantially by a fine gap G between a tapered portion 46 of the adjusting screw 39 and a tapered portion 47 of a screwed hole 43 so that time taken for releasing the pilot pressure is elongated to prevent early closure of the valve 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention makes it possible to prevent the phenomenon of
Regarding the reform of the t7 turbulence valve.

This type of counterbalance valve (back pressure valve), known as a type of pressure control valve, applies back pressure to the cylinder head side in order to prevent heavy objects from falling freely due to load. Barpuyaa/
It is almost the same as the road pulp, but the difference is that it has a built-in check valve for the rounded riser. In other words, if you apply back pressure to the cylinder head side, you can achieve rounding that balances the cylinder K or 64 weight, the pump supply side does not become negative, and you can obtain a constant descending speed.
When raising the piston, sequence pulp without a check valve has the disadvantage that pressure oil cannot be sent from the secondary side to the primary side, and the rounding and rising speed becomes uneven. This problem is solved by using counterbalance pulp.

However, the operation of the counterbalance pulp spreading 11m path is such that the pilot pressure from the pressure side pushes the check gradation/jar of the pulp to fight TMS, and when lowering the heavy object, the p cylinder is activated by hydraulic pressure. Due to the weight of the heavy object, the speed of bong elongation is lower than the bong's elongation speed, causing the bong to roll up, the discharge volume of the bong on the pressure side cannot meet the speed, the pilot pressure decreases, and the counterbalance pulp circuit closes or opens. Therefore, when lowering a heavy object, there is a problem in which the so-called hunting phenomenon is aggravated by intermittent stopping, lowering, stopping, and lowering. The main cause of this hunting phenomenon is the diameter of the nine orifices provided in the pilot circuit. In other words, if the orifice diameter is large, the pilot pressure will cause the check glazer to operate and when the pulp circuit is used, the pilot pressure will immediately escape.
This is because the circuit will be closed, and to prevent this, it is necessary to throttle the ori-swiss to allow time for the pilot pressure to escape.

However, in the past, Oriswiss was generally formed by drilling, so it was not possible to drill micro holes that exceeded the drilling limit, and manufacturing costs increased when holes were drilled by electric discharge machining or the like. The inconvenience was that it was expensive.

The present invention has been made in view of the above-mentioned points, and by disposing an adjusting screw having a flow path in the orifice portion of the pilot circuit, and providing a minute gap at the threshold between the IIJiIk screw and the orifice, The present invention provides a counterbalanced pulp in which the diameter of the orifice can be made substantially smaller, the drilling of the orifice facilitates processing, and the direct placement of the orifice in the pilot circuit can be slightly adjusted to prevent the hunting phenomenon. be.

Hereinafter, the present invention will be explained in detail based on practical examples shown in the drawings.

Figure 41 is a front view of a cylinder equipped with counterbalance pulp according to the present invention, and Figure 2 is the oil pressure wAi of the cylinder.
6 in figure l1. The cylinder 1 has a piston 2 whose head IA side and bottom IBN each have a conduit 3.4.
It is connected to a port (not shown) via a. A counterbalance pulp 6, which will be described later and which is incorporated into a manifold block and arranged around the outer periphery of the cylinder 1, is disposed in the pipe line 3, and this pulp 6 and the pipe line 4 are connected by a pilot circuit 35. . Said cylinder 1
is used, for example, as the boom cylinder 9 of the backhoe 8 shown in FIG. 3, and includes, in addition to the counterbalance pulp 6, a relief pulp T to prevent the boom 60 from falling suddenly due to damage to the hose.

The counterbalance pulp 6 is fitted and fixed into the hole 11 of the manifold block 5, as shown in detail in FIG.
It has a body 14, and a co/pe/center spool 15 that is slidable in the axial direction is fitted inside the cylindrical body 14.

Two annular grooves 16A and 16B are formed at an appropriate interval in the center of the outer peripheral surface of the WJ body 14, and each annular groove #l 116A.

Eleven through holes 17B communicating with 16B are formed in the diametrical direction. Among the two annular #116A and 16B, one annular #16A is communicated with a bo/g (not shown) via a #Il boat 19 provided in the manifold block 5 and a pipe 3, and the other annular groove 16B is connected to the annular groove 16B. is communicated with the shilling head 1A side (see FIG. 2) via a flow path 20 formed in the manifold block 5 and shown by a dotted line.

The compensation center spool 15 is formed into a cylindrical shape with both shoulders open, and an annular #I21 communicating with the through hole 17B of the cocoon recording cylinder 14 is formed on its outer periphery, and the annular groove is formed in the diametrical direction. A through hole 22 communicating with 21 is formed and machined. Further, the compensating center spool 15 is always biased to the left in the drawing by a spring guide 21 interposed between the spool 15 and the spring guide 12 threshold, so that the right am of the annular groove 21 is The inner hole 2SK of the cylindrical body 14 is provided and is normally pressed into contact with the nine-step difference 24. Inner hole 2 of m era conven center spool 15 @
A check plunger 21 constituting a check valve is slidably inserted in the axial direction, and a spring seat 28 that closes the left end opening of the spool 15 is fitted, and this spring seat 28 is fitted with a stop ring. 29 prevents it from coming off. The check plunger 2T is formed in a cylindrical shape with an open left end, and has a through hole 3 on the outer peripheral surface that communicates with the through hole 22 of the compensator mace spool 150.
0 is formed in the direct direction. The check plunger 27 is always biased to the right in the figure by a spring 31 whose one end is press-locked to the spring seat 28. 32 is normally pressed against a step 33 formed in the inner hole 2@ of the co/pe/center spool 15.

For this reason, the through holes 17A and 17B of the cylinder body 140 are not normally in communication with each other, and oil is supplied to the first boat 19 from the ninth bog/g which raises the boom 60, and the oil pressure is applied to the above-mentioned teacup puller/jar 27tl-spring 31. Pressure oil from the cylinder bottom IBIIK valve is supplied from the second boat 37 provided in the manifold block 5, and a portion of this pressure oil is It passes through a pilot circuit 35 to a hydraulic chamber 36 surrounded by the orifice plate 13, the cylinder 14, and the spring seat 28 and the spool 15. Four colors of pilot pressure are applied to the conven center spool 15t''. It is configured so that when it is suppressed and moved to the right against the suffling 23, it misses.

An orifice 38 that communicates the pilot circuit 35 and the hydraulic chamber 36 is formed in the audio orifice plate 13, and an 11 set screw 39 is screwed coaxially with the orifice 38. The adjusting screw 39 has a thread 40 formed on its outer periphery as shown in FIG.
(III S f!2 (see cl)), a screw body 41 that is screwed into the screw body 41, a nine small diameter 1142 protruding from the tip surface of the screw body 41, and a flow path provided in the screw body 41, The channel is a narrow diametrical groove 44 (FIG. 5(a)) formed in the male threaded portion 40, or one end opens at the rear end surface of the screw body 41, and the other end opens at the outer periphery of the small diameter portion 42. It is constituted by a through hole 45 (FIG. 5(b)).The outer periphery of the tip of the small diameter portion 420 is formed in a tapered shape, and the bottom of the screw hole 43 is formed in a tapered shape corresponding to the tapered portion 4@. and adjusting screw 39.
Screwed into Hachiji hole 43, flow rate! ll Adjustment screw part 40
is attached to the orifice plate 13 by caulking with a punch or the like. In this case, the 53rd Q(c
), the tapered portion 46 of the small diameter portion 42 and the screw hole 43
A minute distance 111G is set between the taper portion 47 of
The pilot circuit 35 and the orifice 3B are constantly communicated with each other by this and the flow path provided in the screw body 41.

As a result, the hole diameter of the orifice 38 can be easily set by setting the orifice diameter to be substantially small using the flow path of the adjusting screw 39 and the minute gap G without changing the hole diameter of the orifice 38 itself. . In this case, the outer periphery of the tip of the small diameter portion 42 of the adjustment screw 39 is not formed into a tapered shape, but is chamfered by an appropriate vehicle, and this m-shaped portion and the tapered portion 4 of the screw hole 43 are chamfered.
7 may be provided with a minute gap.

In addition, 50 in the ig4 figure is a plate that closes the hole 11;
1 is a hexagon socket head bolt, 52 is an O-ring, 53° and 54 are backup rings, and 55 and 5ε are retaining rings.

Next, the operation of the counterbalance pulp 6 with the above configuration will be explained i1#i.

As shown in Figure s4, when the counterbalance pulp 6 is closed, the cylinder 1 does not operate and the boom 6
0 is stopped at that position.

In this state, the pump on the cylinder head 1A side is operated, and the counterbalance pulp 6 is pumped from the first port 19.
When pressure oil is supplied to and the check plunger 2T is moved to the left against the spring 31 using the oil pressure, the reverse valve opens through the ninth through hole 17A and is guided into the inner hole 25 of the body 14. Supply oil is supplied to competition/-/inner hole 2 of tarspool 15
6-Through hole 22-1I-shaped groove 21-Cylinder 140 Through hole 17
B - Siri/ through the flow path 20 of the manifold block 5
The piston 2 shown in Figure 2 is supplied to the single person side of the da head.
move to the right. As a result, the backhoe 80 poom@O rises. At this time, the pressure oil on the cylinder/darbottom IB side passes through the second bow) 3F and returns to the tank (not shown) K.

Next, stop the bonder of the first boat 19@, and
When the bonder on the 37 side is operated and 2 cylinder bottom IBIIK pressure oil is supplied, the piston 2 moves to the left in the opposite direction and lowers the poom 60.

A part of this pressure oil is simultaneously used as pilot pressure at a pressure of 1 m1.
36, the co/pe/center spool 15 and the spring seat 28 are moved to the right against the spring 23, and the return circuit of the counterbalance pulp 6 is opened. The return oil from the cylinder head 1A side passes through the flow path 20 - through hole 17B - inner hole z5 of the cylinder 14 and the co/pense/ter spool 150 gap - through hole 17A1 to the first boat. Return to the tank from 111.

Here, when the pilot pressure is introduced to the pressure 'M36 and the counterbalance pulp 6 is opened, if the orifice 38 provided in the orifice plate 13 has a large opening, the pilot pressure immediately decreases and the pulp 6 is closed. However, as mentioned above, in the present invention, all! Since the orifice diameter is substantially reduced by the minute gap G (see Fig. 5) formed by the tapered part 46 of the thread 39 and the tapered part 4T of the threaded hole 43, the time for the pilot pressure to escape is increased, and the counterbalance pulp You can do K to prevent 6 from closing early. As a result, the hunting phenomenon in which the counterbalance pulp 60 circuit closes or opens due to a decrease in pilot pressure can be prevented, and the boom 60 can be smoothly and continuously lowered.

FIG. 6 is a front view when the nine-orange screw 39 used in the above-mentioned example is used as a restrictor of a 7/1 hydraulic circuit;
Figures 7(a) and 7(b) are a front view and a sectional view of a main part in the same case where the adjusting screw 39 is used for the socket pulp 70. In this case, socket pulp TO is placed in cylinder 1.
Lower λ! (Bottom @) If IIC is installed, the speed of cylinder 1 can be slowed down.

It goes without saying that the present invention is not limited to the nine counterbalance pulps shown in Figure 114, but can be applied to various counterbalance pulps.

As explained above, in the counterbalance pulp according to the present invention, an adjusting screw having a flow path is provided in the orifice of the pilot circuit, and a minute gap is provided between the orifice and the adjusting screw, so that the orifice diameter can be substantially adjusted. Because of its small size, the large size of the orifice is easy to process, does not require high precision, prevents a rapid drop in pilot pressure, and allows for a longer pulp closing time. Therefore,
The hunting phenomenon that occurs when lowering heavy objects can be prevented, and the effect is very large.

[Brief explanation of drawings]

Fig. 1 is a front view of a nine-cylinder equipped with counterbalance pulp according to the present invention, Fig. 2 is a hydraulic circuit diagram of the cylinder, and Fig. 3 is a backhoe incorporating the same cylinder as a boom cylinder. 5 is a partial cross-sectional front view showing one row of counterbalanced pulp;
Figures (a) to (C) are side views of the adjusting screw and a cross-sectional view of the main part of the orifice diameter v-), and Figure 6 is the front view of the cylinder showing the actual cylinder when the adjusting screw is used as a restrictor in a hydraulic circuit. Fig. 117(a). tb) also shows a front view and a sectional view of the main part of the cylinder showing an example in which the adjusting screw is used as a socket pulp. @111...e cylinder, 6...counter balance pulp, 14...cylindrical body, 15...compensation center spool, 2"r-fist...check plunger,
35... Pilot circuit, 38... Orifice, 3s... Adjustment screw, 43... Screw hole, 44...
...Groove, 45...Through hole, 46.1...Taber portion, G...Minute gap. Figure 2 Figure 4

Claims (1)

[Scope of Claims] (1) By opening and closing the p cylinder OB passage using the pie night pressure and applying back pressure to the cylinder, the pixel is stopped due to negative pressure, and the pixel is stopped in response to the supplied oil. In counterbalance pulp that maintains control mode, Pilot IIj
An adjustment screw having a flow path is disposed in the orifice portion provided with the 11K, and a small gap smaller than the diameter of the orifice and the OMK screw is provided, and a minute gap between the adjustment screw and the orifice allows the pilot 1Nil diameter and the orifice to be adjusted. A counterbalance valve that communicates with the 9th and 7th. (8) The minute gap is a tapered part formed at the tip of the adjustment screw, and the adjustment screw is screwed into the corresponding adjustment screw. (3) The flow path of the screw is formed in the axial direction on the outer periphery of the screw. The claim li! is characterized in that the base is a nine groove groove! (2) The flow path of the adjustment screw is formed inside the screw, one end opens into the bimit circuit end box, and the other end opens into the end of the screw. !I
3. The counterbalance valve according to claim S1 or 2, wherein the counterbalance valve is a through hole that projects from the outside and opens on the outer periphery of a small diameter portion that has a tapered portion.