JPH0589903U - Vibration suppression circuit device for hydraulic actuator - Google Patents

Abstract

(57) [Abstract] [Purpose] To suppress the vibrations that occur when stopping hydraulic actuators for construction machinery, etc. to improve operability and reduce operator fatigue. [Structure] Two main pipelines 3, 4 leading to the hydraulic cylinder 1
Are connected by a hydraulic shock absorber 12. Hydraulic shock absorber 12
Accommodates a piston 14 and a coil spring 15 in a cylinder 13, and has oil ports 16 and 17 at both ends of the cylinder 13. When the contraction of the hydraulic cylinder 1 is stopped, the pressure of the main pipe line 4 connected to the bottom side oil chamber 1b of the hydraulic cylinder 1 suddenly rises. When the pressure exceeds the set pressure of the hydraulic shock absorber 12, hydraulic oil flows into the piston side oil chamber 20 and absorbs the reaction force generated in the bottom side oil chamber 1b of the hydraulic cylinder 1.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vibration suppressing circuit device for a hydraulic actuator, and particularly to a hydraulic circuit device suppressing a vibration generated when the operation of a hydraulic cylinder is stopped.

[0002]

[Prior Art]

 A conventional hydraulic actuator drive circuit will be described with reference to FIGS. FIG. 3 shows a boom cylinder drive circuit of a hydraulic excavator, and a pilot operated directional control valve 5 is provided in main pipe lines 3 and 4 connecting a hydraulic cylinder 1 for boom drive and a hydraulic pump 2. The directional control valve 5 is controlled by the pilot operating unit 6 and is switched in synchronism with the movement of the operating lever 7 of the pilot operating unit 6, so that the elevation angle of the boom of the hydraulic excavator can be operated. Reference numeral 8 is a pilot hydraulic pump.

Next, the operation of the boom cylinder drive circuit will be described with reference to the timing chart of FIG. Hydraulic excavator operator t₁When the operation lever 7 is rotated to the right side in FIG.₂At time t, the spool of the directional control valve 5 starts moving from the neutral position C to the L position, and t₃The maximum displacement position is reached at. Operation start of the operating lever 7 t ₁ Delay (t from when the directional control valve 5 is activated)₂-T₁) Is caused by the pressure loss of the pilot system and the elasticity of the pilot hydraulic hose.

When the directional control valve 5 is switched from the neutral position C to the L position, the pressure oil 3 from the hydraulic pump 2, the directional control valve 5, and the main pipe 3 are supplied to the piston rod side oil chamber 1 a of the hydraulic cylinder 1. Then, the hydraulic cylinder 1 contracts. When the operator returns the operation lever 7 to the neutral position at time t ₄ , the directional control valve 5 is delayed and starts the returning operation at t ₅ , and becomes the neutral position C at t ₆ .

Since the mass of the entire boom of the hydraulic excavator driven by the hydraulic cylinder 1 is large and the inertia is large, when the return operation of the directional control valve 5 is started at t ₅ and the contraction speed of the hydraulic cylinder 1 decreases, the hydraulic cylinder 1 The pressure in the bottom side oil chamber 1b of No. 1 rapidly increases due to the inertia of the boom (P _{1 in} FIG. 5). Then, due to the reaction force, the piston rod 1c of the hydraulic cylinder 1 is extended, and the pressure in the piston rod side oil chamber 1a rises due to this extension operation (P ₂ ). Subsequently, the hydraulic cylinder 1 contracts due to the reaction force of the surge pressure P _{2 in} the piston rod side oil chamber 1a. Then, the contraction and expansion are repeated in sequence, and the pressure in the bottom side oil chamber 1b and the pressure in the piston rod side oil chamber 1a alternately rise to vibrate the piston rod 1c, and gradually the pressure fluctuation is attenuated and the vibration stops. It

[0006]

[Problems to be solved by the device]

 The above-described conventional hydraulic actuator drive circuit has a problem in operability when the operation of a large-mass moving part such as a boom of a hydraulic excavator is stopped due to vibration of the hydraulic cylinder due to inertia of the boom or the like. Further, the vibration of the hydraulic cylinder causes the vibration of the main body of the hydraulic equipment, increasing the fatigue of the operator and reducing the work efficiency.

Therefore, there is a technical problem to be solved in order to suppress the vibration generated when the hydraulic actuator stops to improve the operability and reduce the physical burden on the operator to improve the work efficiency. This invention aims to solve the above problems.

[0008]

[Means for Solving the Problems]

 This invention is proposed to achieve the above-mentioned object, and in a hydraulic machine in which a hydraulic actuator is controlled by a directional control valve, a piston and a rod are housed in a cylinder and the piston is removed. Urging in the direction of the cylinder to form an oil port at both ends of the cylinder to form a hydraulic shock absorber, and connect the piston side oil port of the hydraulic shock absorber with one of the main pipelines of the hydraulic actuator to connect the hydraulic shock absorber. The oil port on the spring side of the container and the other main line of the hydraulic actuator are connected, and the operating pressure of the hydraulic shock absorber is set higher than the operating pressure of the one main line and less than or equal to the surge pressure of the main line. The present invention provides a vibration suppressing circuit device for a hydraulic actuator.

[0009]

[Action]

 When the pressure in the main pipe branching to the oil port on the piston side of the hydraulic shock absorber rises sharply, for example, by stopping the hydraulic cylinder, and exceeds the set pressure of the hydraulic shock absorber, the piston of the hydraulic shock absorber is pushed down and the piston Hydraulic oil flows into the side oil chamber. This suppresses the pressure rise in the main pipeline.

On the other hand, due to the movement of the piston of the hydraulic shock absorber, the hydraulic oil in the spring-side oil chamber is discharged to the other main pipeline, which eliminates the imbalance of the main pipeline pressure generated by inertia when the hydraulic cylinder is stopped, and the reverse Since the generation of force is suppressed, the piston of the hydraulic cylinder stops smoothly without vibrating.

[0011]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. The circuit configurations of the hydraulic cylinder 1, the directional control valve 5, the hydraulic pumps 2, 8 and the pilot operating unit 6 shown in FIGS. 1 and 2 are the same as those shown in FIG. 3 as a conventional example. The hydraulic shock absorber 12 constituting the vibration suppression circuit device 11 shown in FIG. 1 accommodates a piston 14 and a coil spring 15 in a cylinder 13, and the piston 14 is pressed against one end of the cylinder 13 by the coil spring 15. . Oil ports 16 and 17 are provided at both ends of the cylinder 13, and the piston side oil port 16 is connected to a main pipe line 4 communicating with a bottom side oil chamber 1b of the hydraulic cylinder 1 by a pipe line 18. Further, the spring side oil port 17 is connected to a main pipe line 3 communicating with a piston rod side oil chamber 1a of the hydraulic cylinder 1 via a pipe line 19.

The spring constant of the coil spring 15 is set to be higher than the operating pressure of the main pipe line 4 on the bottom side and lower than the surge pressure generated in the main pipe line 4 at the time of the stop operation, and the hydraulic cylinder 1 is normally operated. The piston 14 is formed so as not to move under pressure. Next, the operation of the vibration suppression circuit device 11 will be described. Since the pressure in the main pipe 4 is within the operating pressure when the operating lever 7 is in the neutral state and the rotating state, the piston 14 of the hydraulic shock absorber 12 is pressed against the piston side oil port 16 by the bias of the coil spring 15. ing.

When the operation lever 7 is rotated to the right and the hydraulic cylinder 1 is contracted and then the operation lever 7 is returned to the neutral position, the main conduit 4 on the bottom side due to the inertia of the boom or the like as described in the conventional example. The pressure rises above the operating pressure. When this surge pressure exceeds the set pressure of the hydraulic shock absorber 12, the piston 14 of the hydraulic shock absorber 12 is pushed in, and the oil amount V for the displacement of the hydraulic cylinder 1 (V = A · Δχ, where A = the cross-sectional area of the hydraulic cylinder , Δχ = the piston displacement amount of the hydraulic cylinder) flows into the piston side oil chamber 20 and the pressure increase in the main pipeline 4 is suppressed.

Further, hydraulic oil of the same amount as the inflowing oil amount is sent from the spring side oil chamber 21 to the main pipe line 3 on the piston rod side, and the pressure drop of the main pipe line 3 on the piston rod side due to the displacement of the piston of the hydraulic cylinder 1. To compensate. Then, the piston 14 of the hydraulic shock absorber 12 moves back and forth according to the pressure until the peak pressure of the pulsation of the bottom side main pipeline pressure falls below the set value of the coil spring 15, and the hydraulic pressures of the two main pipelines are reduced. The piston rod 1c of the hydraulic cylinder 1 is smoothly stopped by balancing.

When the hydraulic cylinder 1 is driven in the extension direction and stopped, the pressure in the piston rod side oil chamber 1a rises due to the inertia of the movable part such as the boom, and the hydraulic cylinder 1 reverses to the contraction direction. The pressure fluctuation after reversal has almost the same waveform as when the operation in the contraction direction was stopped. For this reason, at the time of reversal after once stopped, the hydraulic shock absorber 12 operates to suppress the vibration of the hydraulic cylinder 1 in the same manner as when the contraction is stopped as described above.

FIG. 2 shows another embodiment. A counter balance valve 33 including a relief valve 31 and a check valve 32 is inserted between the piston side oil port 16 of the hydraulic shock absorber 12 and the main pipe line 4. ing. The primary pressure side oil port 34 of the counter balance valve 33 is connected to the main pipe line 4 on the bottom side, and the flow of hydraulic oil from the main pipe line 4 to the hydraulic shock absorber 12 is controlled by the relief valve 31. The pressure for operating the hydraulic shock absorber 12 is set by setting the operating pressure of the relief valve 31.

When the operation lever 7 is returned from the right side to the neutral position in the figure to stop the contraction of the hydraulic cylinder 1, the hydraulic oil in the bottom side main pipeline 4 is compressed and the pipeline pressure is reduced to the relief valve 31. When the set pressure is exceeded, the relief valve 31 opens and hydraulic oil is accumulated in the piston side oil chamber 20 of the hydraulic shock absorber 12 as in the case shown in FIG. Therefore, the reversal pressure for expanding the hydraulic cylinder 1 is suppressed, and the vibration of the piston rod does not occur.

[0018]

[Effect of the device]

 As described in detail in the above-mentioned one embodiment, this invention absorbs surge pressure generated when the hydraulic actuator stops operating by means of the hydraulic shock absorber, so that the reaction force is reduced and the hydraulic actuator and the hydraulic equipment main body are reduced. Vibration is suppressed and operability is improved. Further, since the vibration is reduced, the degree of physical fatigue of the operator is significantly reduced, which contributes to the improvement of workability.

[Brief description of drawings]

FIG. 1 is a hydraulic actuator drive circuit diagram showing a vibration suppression circuit device of the present invention.

FIG. 2 is a hydraulic actuator drive circuit diagram showing another embodiment.

FIG. 3 is a conventional hydraulic actuator drive circuit diagram.

FIG. 4 is a timing chart of each part by a conventional hydraulic actuator drive circuit.

[Explanation of symbols]

 1 Hydraulic Cylinder 3, 4 Main Pipe Line 5 Directional Control Valve 7 Operation Lever 11 Vibration Suppression Circuit Device 12 Hydraulic Shock Absorber 13 Cylinder 14 Piston 15 Coil Spring 16 Piston Side Oil Port 17 Spring Side Oil Port 20 Piston Side Oil Chamber 21 Spring Side Oil Room

Claims (1)

[Scope of utility model registration request] 1. A hydraulic machine for controlling a hydraulic actuator with a directional control valve, wherein a piston and a spring are housed in a cylinder to urge the piston in one direction, and oil ports are provided at both ends of the cylinder. A hydraulic shock absorber is formed, and a piston side oil port of the hydraulic shock absorber is connected to one main pipeline of the hydraulic actuator, and a spring side oil port of the hydraulic shock absorber is connected to the other main pipeline of the hydraulic actuator. At the same time, a vibration suppressing circuit device for a hydraulic actuator, in which an operating pressure of the hydraulic shock absorber is set to be higher than an operating pressure of the one main pipeline and equal to or lower than a surge pressure of the main pipeline.