JPS60241506A - Cylinder controlling device - Google Patents

Abstract

PURPOSE:To improve the effect of saving energy by enabling a period of changing over a direction change-over valve to be adjusted by an regulator according to a piston position detecting signal at the hitting stroke end. CONSTITUTION:A variable throttle valve 24 is disposed in a path 30 for interconnecting a chamber 9 and a path 17, and a period of changing over a direction change-over valve 5 according to a piston position detecting signal at the hitting stroke end is adjusted by the variable throttle valve 24 to coincide with a piston kicking-up point of a piston. Thus, fluid energy can be recovered or saved by kicking up the piston so that energy saving can be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cylinder control device used in a device that repeatedly strikes an object by a reciprocating piston of the cylinder control device, such as a hydraulic breaker, a pile driver, and a punching press.

This type of cylinder control device is, for example, as shown in FIG.
3), pop the small pressure chamber (2) on the pressure receiving surface (4).
), and the pressure chamber (3) with a large pressure-receiving surface is alternately communicated with the pump (4) and the tank (6) by a directional switching valve (5) with 6 points and 2 positions. When the directional control valve (5) is in position B, the pressure chamber (3) communicates with the tank (6), so the piston (7) moves to the right in the figure [return stroke, upward stroke], and at the end of the return stroke. , pilot room O
A chamber communicating with a (131) and a chamber communicating with tank (6) (
When the piston rod (19) communicates with the piston rod (19) through the annular groove 0e, the directional control valve (5) is switched to position A by the pump hydraulic pressure in the pilot chamber C23, and the pressure chamber (3) K also receives the pump hydraulic pressure. so that the piston (7) is in the pressure chamber (2) (3
) moves to the left in the figure [impact stroke, descending stroke] and strikes the object to be hit (8) at the end of the striking stroke. At that time, the pressure chamber (2) and the chamber (9) communicate with each other through the annular groove (11) of the piston rod (10), and the directional control valve (5) moves from position A to position B by the pump hydraulic pressure acting on the pilot chamber O2. As soon as the force of the piston hits the hit object (8), it reverses and moves to the right in the figure, and the above-described operation is repeated.

By the way, when hitting the object to be hit (8), if the object to be hit is hard, the piston (the force will jump). However, in the conventional device, when the force hits the piston (the object to be hit (8)), the directional control valve (
5) immediately switches to position B, and at this time the piston (if the force jumps up faster than the flow rate of the pressure liquid into the pressure chamber (2), a large negative pressure is created in the pressure chamber (2) K, so this negative pressure Therefore, the piston (7) can only obtain a speed corresponding to the flow rate of the pressure fluid supplied to the pressure chamber (2), and the piston's jump energy cannot be utilized. Ta.

An object of the present invention is to recover or save fluid energy by utilizing the piston jumping phenomenon that occurs when the piston hits an object to be hit.

In order to achieve the above object, the present invention includes two stroke end position detection means for detecting the stroke end position of a piston in a double acting cylinder/cylinder, and a piston position detection signal that is alternately received from both stroke end position detection means. A cylinder control device that is equipped with a directional valve that alternately connects the pressure chamber of a double-acting cylinder to a pressure source and a tank, in which the timing of switching the directional valve is adjusted by an adjusting means based on a piston position detection signal at the end of the impact stroke. It is.

The present invention will be explained below based on embodiments shown in the drawings. 1st
In the figure, among the pressure chambers (21 (3)) of the double-rod double-acting cylinder (1), the pressure chamber (2) with a small pressure receiving surface is communicated with the pump (4) via the flow path @C1! The pressure chamber (3), which is larger than the pressure chamber (2), has a flow path (21) and a tank (6) that communicate with the pump (4) via a 6-port directional control valve (5). The return channels (19 are alternately connected to the

Tafururosodo double acting 7 cylinder (1) piston rod 0■
At the base of the piston, there is provided an annular 111013 that communicates the pressure chamber (2) and the chamber (9) at the end of the striking stroke of the sword, and at the tip of the piston rod (19, there is a chamber Q31041 at the end of the return stroke of the piston). In addition to providing a communicating annular groove Q6), the chamber (+31 is a passage 07) connects the chamber (9).
is connected to the pilot chamber (121) of the directional control valve (5) from the passage (to) Q7)K, and the chamber Q41 is connected to the return passage (19) of the directional control valve (5). (5) In order to take position A when no pump hydraulic pressure acts on the pilot chamber side, a pilot chamber whose pressure receiving surface is smaller than the pilot chamber 02 is provided, and the pump hydraulic pressure is always guided to this.

The above configuration is the same as the conventional device shown in FIG.

In this embodiment, in the above configuration, a passage C30)K connecting the chamber (9) to the passage 07) has a flow control valve such as a variable throttle valve c! 4). This variable throttle valve adjusts the flow rate of the pump-side pressure fluid guided to the pilot chamber 021 of the directional control valve (5) at the end of the impact stroke, and the piston (force hits the object to be hit (8) and jumps). The directional control valve (5) is set so as to switch to position B when the position is reached.

This will be explained with reference to FIG. The vertical axis is the piston stroke,
The horizontal axis is time. In Figure (1), the piston descends from the end of the return stroke (A) to the end of the impact stroke (B), and when the directional control valve is switched at this point, the piston rises to the end of the return stroke (C). The time required for this rise is a. It is. Now, looking at only this return stroke in FIG. (II), when the direction switching valve is switched at the end of the impact stroke (b), the piston moves upward as shown by the solid line a under the pump hydraulic pressure.

Next, in the case of broken line S, the switching timing of the switching valve at the end of the impact stroke is shifted by bl, and the piston jump stroke during this period is changed to Sb.
Then, the piston moves from the end of the stroke (b) to the jump point (
), then jumps up to the end of the return stroke (g), then rises parallel to the solid line a [at the same speed] from (g) to the end of the return stroke (g), and reaches the end of the return stroke (g), and this rising time Lotus. So, the ``second rise time a'' for the solid line a without jump. It is significantly shorter than . In addition, the opening direction switching valve from (b) to (f) is located at position A and communicates with the pressure chambers (21 (3)) on both sides of the piston, so the pressure fluid caused by the piston jumping is transferred to the pump side. Since the pressure liquid is pushed back to the pressure chamber (21K), no vacuum is generated.Moreover, since the pressure receiving area of the pressure chamber (3) is larger than that of (2)K, there is a large amount of liquid returned to the pump side, and pressure liquid accumulates on the pump side. If there is a mechanism, for example an accumulator, excess pressure fluid can be collected and stored, and then released when needed.Therefore, from the perspective of the pump, the consumption flow rate of the pressure fluid equivalent to the jump of the piston is zero or the recovery capacity. .However, in the case of the broken line S, the number of strikes increases due to the shortening of the rising time.Next, in the case of the dashed line C, the time from when the piston hits the object to be struck until the switching valve is switched is excessive. In this case, the directional control valve remains in position A, so the piston that jumped up descends again from the jump point (a) and rises at the end of the re-stroke stroke (from 1 to the re-jump point (nu)). The directional control valve has been switched, and the pump will rise from the point where it jumps again to the rising end under the pressure of the pump fluid.

In this example, the rising time is C6, which is wasteful in terms of time and significantly reduces the number of hits. Therefore, it is important to find the optimum value for the switching time.

In the embodiment shown in FIG. 6, a variable throttle valve Q (a) is interposed between the passage θ force connected to the pilot chamber IJ7J of the directional control valve (5) and the flow passage (two swords) connected to the pump (4). passage 2
5), and the other configuration is the same as the circuit configuration shown in FIG. 1 except for the variable throttle valve Oa. In this embodiment, when the switching delay of the directional control valve (5) is large, an appropriate amount of pump pressure fluid is supplied from the variable throttle valve (2 (a) to the pilot chamber 02 in advance.
) to obtain the optimal replacement time.

In the embodiment shown in FIG. 4, a passage 0η connecting to the pilot chamber 0 of the directional control valve (5) and a passage connecting to the return passage (1) are connected to the variable throttle valve (2 (a)). They communicate through an interposed passageway 4, and the other configuration is the same as the circuit configuration shown in FIG. 1 except for the variable throttle valve (24).

In this embodiment, if the switching time of the directional control valve (5) is too early, the optimum switching time can be obtained by releasing a small amount of the pressure fluid in the passage 07) to the tank side using the variable throttle valve Q(a) in advance. I have to.

In the embodiment shown in FIG. 5, the 6-point, 2-position switching valve in the hydraulic circuit shown in FIG. 1 is replaced with a 4-point, 2-position switching valve. In this embodiment, in the illustrated state in which the directional control valve t27) is in position B, the pump pressure liquid is introduced into the pressure chamber (2), and the pressure chamber (3) communicates with the tank (6), so that the piston (7)
moves to the right (rises) in the figure, and the piston reaches the end of the return stroke.The chamber 13) Q4) communicates with the piston rod (19) through the annular groove Oe, and the pilot chamber +1'lJ connects to the tank (6).
When the switch valve (5) is connected to the tank (6), the switching valve (5) is switched to the position A, and the pump pressure liquid flows into the pressure chamber (3) K, and the pressure chamber (2) is connected to the tank (6).
), the force travels to the left in the figure and strikes the object (8) at the end of the striking stroke.

In this case, the directional control valve (27) and the pilot chamber (12
The piston is set to take position A until it reaches the jump point by the action of a variable throttle valve (24) that throttles the amount of pump pressure fluid supplied at No. 5, and the piston (7)
) When the piston hits K and jumps up, the liquid returns from the tank side to the pressure chamber (2) due to the negative pressure caused by the jump, so no vacuum is created, and the pressure liquid in the pressure chamber (3) flows out of the piston. The excess pressure fluid that is pushed back toward the pump (4) is collected and stored in an accumulator (not shown).

When the piston reaches its lifting point, the directional valve (27) switches to position B and the piston continues to rise due to the pressure fluid from the pump.

The embodiment shown in FIG. 6 connects the pilot chamber of the directional valve (5) to the flow path (toward) communicating with the pump (4) using a check valve (2) that allows fluid flow only to the pilot chamber (23). A passage (29) in which the second and variable throttle valves 241 are arranged in parallel, and the other configuration is the same as the circuit configuration except for the variable throttle valve in FIG. The pilot chamber (1) of the switching valve (5) is pushed by the pump side pressure liquid and is pushed out from the pilot chamber c! I'm trying to find time.

Note that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the gist thereof. For example, one pilot chamber (two moats) of the directional control valve may be replaced with a spring. Also, an appropriate known flow control valve may be used instead of the variable throttle valve. Also, the stroke end position detection means Alternatively, a limit switch may be used to switch a normally closed valve connected to the pilot chamber of the directional control valve from closed to open using the piston position detection signal.

As explained above, according to the present invention, since the timing of switching the directional control valve based on the piston position detection signal at the end of the percussion stroke is adjusted to the jump point of the piston by the adjusting means, the fluid energy due to the jump of the piston is It is possible to provide a cylinder control device that can recover or save energy and has a large energy-saving effect.

FIG. 2 is a diagram showing the relationship between the piston lift stroke and the directional control valve switching time, and the relationship between the piston stroke and time, and FIG. 7 is a hydraulic circuit diagram showing an embodiment of the present invention. FIG.

1...Double rod double acting cylinder, 2. Ro...Pressure chamber, 4. Pump, 5.27. Directional switching valve, 8. Hit object, 9, 13.14. Chamber, 11.16. Annular groove, 2.
4-・Variable throttle valve.

Patent applicant: Kawasaki Heavy Industries, Ltd. Agent: Patent attorney Kenzo Ota

Claims (1)

[Claims] 1. Two stroke end position detection means for detecting the stroke end position of the piston in the double acting cylinder, and a piston position detection signal alternately received from both stroke end position detection means to detect the pressure of the double acting cylinder. A cylinder control device equipped with a directional valve that alternately connects a chamber to a pressure source and a tank, characterized by comprising an adjusting means for adjusting the timing of switching the directional valve based on a piston position detection signal at the end of a percussion stroke. /Linda control device. 2. Claim 1, wherein the directional switching valve is a pilot-operated switching valve, and the directional switching valve switching timing adjusting means is a flow rate control valve.
Cylinder control device as described in section.