JP2577406Y2 - Vibration prevention device at the time of stop of actuator with inertial load - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention is intended to reduce the vibration generated when an actuator having a large inertial load such as a boom cylinder of a power shovel is operated and then suddenly stopped is reduced as early as possible, thereby reducing operator fatigue. The present invention relates to a stop-time vibration preventing device that reduces the noise and improves the operability.

[0002]

BACKGROUND ART FIG. 4 (A) is a basic hydraulic circuit used in the working machine system such as a power shovel, the pump 11 and tank 12 are connected to the oil supply port and the drain oil port of the directional control valve 13, the direction The two output ports of the switching valve 13 are connected to the line 14,
The actuator 16 is connected to a head-side chamber 16a and a rod-side chamber 16b of an actuator (such as a boom cylinder of a power shovel) 16 via an actuator 15. The actuator 16 operates an inertial load such as a boom. An operation position 13b shrinkage upper neutral position 13a actuator among three positions shown in FIG. 4 (A) to the indicated direction switching valve 13, the lower actuator extended operating position 13c.

When the directional control valve 13 is returned to the neutral position 13a while the pressure oil supplied from the pump 11 is supplied to and discharged from the actuator 16 via the directional control valve 13, the position between the directional control valve 13 and the actuator 16 is reduced. for compression of chamber oil conduit 14, 15 and actuator 16, after neutral return of the directional control valve 13 as shown in the upper diagram in FIG. 4 (B), FIG. 4
(B) As shown in the lower diagram, the inertial load 17 of the actuator 16 causes residual vibration with poor damping. The changes over time in the pressure of the head-side chamber 16a and the rod-side chamber 16b of the actuator (boom cylinder) 16 at this time are shown by dotted lines in FIG.

[0004]

As shown [devised Problems to be Solved] in FIG 4 (B) and FIG. 2, the actuator operating speed be returned to the directional control valve 13 to the neutral position 13a is not immediately zero and gradually attenuates appeal but since the residual vibration shown in the lower part of FIG. 4 (B) in some cases, be up to more than 10 times, an operator such as a power shovel fatigue feeling the residual vibration of the (Vomiting sense) That is not uncommon.

The present invention has been made in view of such a point, and reduces vibration generated when an actuator having a large inertial load is suddenly stopped as early as possible.
It is an object of the present invention to provide a stop-time vibration preventing device that reduces operator fatigue and improves operability.

[0006]

According to the first aspect of the present invention, there is provided a fluid pressure circuit in which a fluid pressure generated by a fluid pressure source is controlled to be supplied to and discharged from an actuator operated by the fluid pressure by a directional switching valve. while one of the conduit and one chamber output port and the actuator and connection of the directional control valve, and the other conduit connecting the other chamber of the other output port and the actuator of the directional control valve, whereas Pipeline and the other pipeline
Between, comprising a damping device which is provided through a pair of diaphragm, the damping device, the device
Body, a low inertia piston slidably fitted within the device body, and a compartment formed by the low inertia piston
By a pair of damping chamber in communication with the respectively each aperture, low inertia piston is provided on the rod end
Small-diameter piston and large-diameter piston
And the damping chamber faces the small-diameter piston.
And the head side chamber of the cylinder actuator
Head side damping chamber with small cross-sectional area and large diameter
Of the cylinder type actuator
Rod-side damping chamber with a large cross-sectional area
This is a vibration prevention device for an actuator having an inertial load when the actuator is stopped.

[0007] The invention according to claim 2 is a device according to claim 1 .
In the vibration prevention device at stoppage, one of the damping chambers
A load offset spring is provided.

[0008]

According to the first aspect of the present invention, the vibration pressure generated by the actuator is guided to the damping chamber of the damping device through the throttle, and the low inertia piston is slid, whereby the vibration energy is consumed by the throttle to generate heat. Thus, the vibration generated when the actuator is stopped is attenuated at an early stage. In particular, the damping chamber has a small diameter and a large diameter.
Due to the eccentric load acting on the inertial load,
The head side is higher in time average than the rod side
The cross-sectional area of the damping chamber connected to the head
Structure smaller than the cross-sectional area of the damping chamber connected to the
And the pressure of the low inertia piston
The area of the high pressure side is smaller than that of the low pressure side.
Balance in a position where it can move freely.

[0009] The invention according to claim 2 is a device for unbalanced inertia load.
As the weight increases, the low inertia piston
It is pressed against the end of the pumping chamber and stops.
In this state, the effect of the damping device is lost.
By providing an offset load offset spring,
Corresponds to excessive inertial load.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to FIG.
Ru shown in 3 strange Katachirei referring to will be described in detail.

FIG. 1 is a basic hydraulic circuit used in a working machine system of a power shovel, in which a pump 11 and a tank 12 are connected to an oil supply port and an oil discharge port of a directional control valve 13. One output port is connected to one conduit 14 and
The actuator 16 is connected to a head-side chamber 16a and a rod-side chamber 16b of an actuator (such as a boom cylinder of a power shovel) 16 via the other conduit 15, and the actuator 16 supports an inertial load 17 such as a boom. The upper side of the neutral position 13a among the three positions of the direction switching valve 13 shown in FIG. 1 is the actuator contraction operation position 13b, and the lower side is the actuator extension operation position 13c.

A branch pipe 14a branched from a pipe 14 connecting one output port of the direction switching valve 13 and the head side chamber 16a of the actuator 16 is provided at a port provided at one end of a device body 22 of the damping device 21. 23, and the other output port of the directional control valve 13 and the actuator.
A branch pipe 15a branched from a pipe 15 connecting the 16 rod-side chambers 16b communicates with a port 24 provided at the other end of the device body 22 of the damping device 21.

A pair of throttles (hereinafter referred to as orifices) 25 and 26 for exhausting vibration energy by heat generation are provided in the port portions 23 and 24 of the branch pipes 14a and 15a.
Each is provided. The orifices 25, 26 may be provided in-line in the pipes of the branch pipes 14a, 15a.

In the damping device 21, a small-diameter cylinder 31 and a large-diameter cylinder 32 are continuously formed in the device body 22 between the pair of orifices 25 and 26, and a low inertia piston 33 is formed in each of the cylinders 31 and 32 . A small-diameter piston portion 33a formed at one end of the rod and a large-diameter piston portion 33b formed at the other end of the rod are slidably fitted by a seal 34 in a liquid-tight manner.

The small-diameter piston portion 33a faces a head-side damping chamber 35 formed in the small-diameter cylinder 31, and the large-diameter piston portion 33b has a large-diameter rod formed in the large-diameter cylinder 32. Facing the side damping chamber 36.

The head side damping chamber 35 is connected to the head side branch pipe 14a via the orifice 25, and the rod side damping chamber 36 is connected to the rod side branch pipe 15a via the orifice 26. Small diameter piston 33a and large diameter piston
An intermediate chamber 37 between the tank 33 and the tank 33b is communicated with the tank 12 by an oil drain pipe 39 drawn from a drain port 38.

The reason why the diameters of the damping chambers 35 and 36 are made small and large is that, because an eccentric load (gravity) F acts on the inertial load 17, the head side chamber 16a of the actuator 16 is time-averaged from the rod side chamber 16b. This is to prevent the low inertia piston 33 from being biased toward the damping chamber 36 due to the high pressure. That is, the pressure receiving area of the piston portion 33a facing the damping chamber 35 connected to the relatively high pressure head side chamber 16a is increased by the piston portion 33b facing the damping chamber 36 connected to the relatively low pressure rod side chamber 16b. By making the pressure receiving area smaller than the pressure receiving area, the forces applied to both end faces of the low inertia piston 33 are balanced when averaged over time, and the low inertia piston 33 is maintained in a balanced state inside the damping chambers 35 and 36.

Next, the operation of the embodiment shown in FIG. 1 will be described.

In FIG. 1, the directional control valve 13 is moved to a neutral position 13a.
When the actuator is returned to the neutral position 13a after operating to the actuator retracting operation position 13b or extension operation position 13c,
If there is no damping device 21, the pressure oscillation is repeated as shown by the actual measurement data indicated by the dotted line in FIG. Due to the presence of the damping device 21, the vibration pressure due to the compressibility in the pipelines 14, 15 acts on both ends of the low inertia piston 33.

Therefore, when the vibration pressure reverses on the head side and the rod side, the low inertia piston 33 slides in reverse from the balance point in the same cycle as the oscillation cycle. During this time, pipeline 14,
The oil flow accompanying the compressibility in 15 loses vibration energy due to heat generation through the throttle resistance of the orifices 25 and 26.

On the other hand, since the load 17 of the actuator 16 has a large inertia, the low inertia piston 33 almost completely absorbs the compressible oil for generating the vibration, so that the vibration is rapidly stopped. The state of vibration damping when the damping device 21 is provided in the hydraulic circuit is shown by actual measurement data indicated by a solid line in FIG.

FIG. 2 shows the change over time in the cylinder head side pressure and the rod side pressure when the boom cylinder for moving the boom of the power shovel up and down is operated as the actuator 16, and FIG. FIG. 2B shows a change in cylinder rod side pressure at the time of stop of boom raising, FIG. 2C shows a change of cylinder head side pressure at the time of stop of boom lowering,
FIG. 2D shows a change in cylinder rod side pressure at the time of boom lowering stop.

As described above, the vibration pressure generated by the actuator 16 is guided to the damping chambers 35, 36 of the damping device 21 via the orifices 25, 26, and the low inertia piston 33 is slid, thereby causing the orifices 25, 26 to slide. , The vibration energy is consumed by heat generation, and the vibration generated when the actuator 16 stops is attenuated at an early stage.

Further, an eccentric load acts as the inertial load 17, and the head side of the actuator 16 has a high pressure when averaged over time from the rod side.
Are small and large, and the cross-sectional area of the damping chamber 35 connected to the high-pressure head side is smaller than the cross-sectional area of the damping chamber 36 connected to the rod side. Then the balance position is maintained.

FIG. 3 shows a first modification 21a of the damping device, in which an offset load offset spring 41 is provided in the rod-side damping chamber. This is because when the eccentric load (gravity) F of the inertial load 17 increases, the low inertia piston 33 is pressed against the inner end of the rod side damping chamber 36 and stops, and in this state, the effect of the damping device is lost. By providing the offset load offset spring 41, an excessive offset load (gravity)
That corresponds to F.

[0026]

[Effect of the invention] According to the invention of claim 1, a vibration pressure generated in the actuator is guided to the pair of damping chamber of the damping device through a pair of squeezing by sliding the low inertia piston, Vibration energy can be efficiently consumed by heat generation by a pair of throttles, and residual vibration generated when the actuator is suddenly stopped can be attenuated at an early stage. For example, fatigue of an operator operating a construction machine vehicle having a large inertial load is reduced. And operability can be improved.

In particular, the head of a cylinder type actuator
Lock the cross-sectional area of the head-side Damping chamber connected to the side chamber is
From the cross-sectional area of the rod-side damping chamber connected to the
It has a small structure and enters the head side damping chamber
Pressure is received by the small diameter piston part of the low inertia piston
The pressure entering the rod-side damping chamber is
The cylinder-type actuator head
Low inertia even when the eccentric load due to the gravitational inertia load acts on the side
The piston can be prevented from shifting to the bias position, and low inertia piston
To a position where it can move freely.
You.

Further, the low inertia piston is provided at one end of the rod.
Due to the small diameter piston and the large diameter piston at the other end of the rod
Since only the pressure receiving part is formed to the required diameter, truly low inertia and
Can be sensitive to pressure fluctuations in the damping chamber
it can.

The low inertia piston has a small diameter piston.
The entire piston part and the large-diameter piston part are
Mated with rod side damping chamber and rod side damping chamber
Because it is not projected outside, safety can be ensured.

According to the invention of claim 2, the unbalanced load offset spring, can be reliably prevented migration to bias the position of the low inertia piston by unbalanced load.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a stop vibration prevention device according to the present invention.

FIG. 2 is an actually measured hydraulic pressure waveform diagram showing a change with time of a cylinder head side pressure and a rod side pressure when a boom cylinder is operated with and without a vibration prevention device.
Is a waveform diagram showing a change in cylinder head side pressure when stopping the boom raising, B is a waveform diagram showing a change in cylinder rod side pressure when stopping the boom raising, C is a waveform diagram showing a change in cylinder head side pressure when stopping the boom lowering, D is a waveform diagram showing a change in cylinder rod side pressure at the time of boom lowering stop.

3 is a cross-sectional view showing a modification Katachirei of the same anti-vibration equipment.

FIG. 4A is a boom for explaining a conventional problem.
Hydraulic circuit diagram for cylinder, (B) shows the directional control valve and
FIG. 5 is a waveform diagram showing a change over time of a boom cylinder speed.
You.

[Explanation of symbols]

 13 Directional valve 14, 15 Pipeline 16 Fluid pressure actuator 16a Head side chamber 16b Rod side chamber 21 Damping device 22 Device body 25, 26 Restrictor 33 Low inertia piston 33a Small diameter piston part 33b Large diameter piston part 35 Head side damping chamber 36 Rod side Damping chamber 41 Spring for offset load offset

Continuing from the front page (72) Inventor Yoshio Aso 2337 Inami, Inami-cho, Kako-gun, Hyogo Prefecture Inside the Akashi Machinery Works Tsuchiyama Plant (56) References JP-A-63-30601 (JP, A) (58) Fields surveyed (Int.Cl. ⁶ , DB name) F15B 11/00-11/22 E02F 9/22

Claims (2)

(57) [Scope of request for utility model registration] 1. A fluid pressure circuit in which a fluid pressure generated by a fluid pressure source is controlled to be supplied to and discharged from an actuator operated by a fluid pressure by a direction switching valve, wherein one output port of the direction switching valve and one of the actuators are provided. between the one conduit connecting the chamber, and the other conduit and the other output port and the other chamber of the actuator are connected directional control valve, between one conduit and another conduit, Through a pair of apertures
; And a provided damping device, the damping device comprises a device body, and low inertia piston slidably fitted within the device body, and each aperture is defined and formed by the low inertia piston its
And a pair of damping chambers which communicate respectively communicating, low inertia piston includes a small-diameter piston section provided on the rod end, and a large-diameter piston section provided on the rod the other end, the damping chamber is small Cylinder type actuator provided facing the piston
Head-side damper with a small cross-section that communicates with the
And ring chamber, the cylinder-shaped actuator disposed facing the large diameter piston portion
Rod-side damper with a large cross-sectional area that communicates with the rod-side chamber of the motor
A vibration prevention device for an actuator having an inertial load when the actuator is stopped, comprising: 2. An eccentric load provided in one damping chamber.
2. The apparatus according to claim 1, further comprising an offset spring .