JPH0530252U - Hydraulic shovel front damping system - Google Patents

Abstract

(57) [Summary] [Purpose] In the past, vibration from the front part was transmitted to the cab, which sometimes hindered the operation of the operator. An object of the present invention is to suppress the above-mentioned vibration of the front part by a hydraulic control system for absorbing the vibration of the front part. A front damping device for a hydraulic excavator in which a vibration damping device including a hydraulic control system for rapidly damping front vibration is provided and the damping device is activated only when a hydraulic cylinder is stopped.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vibration damping system for a front portion of a construction machine such as a hydraulic excavator and a wheel loader, and particularly to a front vibration damping system for a hydraulic excavator.

[0002]

[Prior Art]

 In the conventional hydraulic excavator, as shown in FIG. 4, the constituent parts of the hydraulic excavator can be largely divided into a front part, a machine body 9, a cab 10, and a traveling device 11. The front part is composed of a boom 1, an arm 2, a bucket 3, a boom cylinder 4, an arm cylinder 5, a bucket cylinder 6, a strap 7 and a rod 8, and the respective constituent parts are pin-connected. The excavation and loading are performed by expanding and contracting the three cylinders by the lever operation of the operator inside the cab 10. By the way, in order to move the bucket 3 to a desired place and perform the work, the boom, the arm, and the cylinders for operating the respective members for operating the bucket are expanded and contracted to perform excavation loading and other work. It was necessary to inject the pressure oil into the oil chamber or to discharge the pressure oil from the oil chamber, and a large vibration was often generated each time. However, the operator has endured the vibration and continued working. However, in recent years, attention has been paid to safety issues, research to eliminate harsh labor, improve difficult tasks, and eliminate those tasks if possible, so that anyone can do the work. In particular, they have been particularly focusing on issues such as improving the working environment. In that sense, research on the operation of power shovels has not been sufficiently conducted.

[0003]

[Problems to be solved by the device]

 Conventionally, as shown in Fig. 3, no vibration prevention measures have been taken in the hydraulic circuit of the boom cylinder. As a result, as shown in FIG. 4, when the arm cylinder 5 and the bucket cylinder 6 are fixed and the length of the boom cylinder 4 is changed and stopped, the front portion becomes long, and therefore the boom foot pin of its own size is very large. Vibration of the entire front is induced by the oil column spring based on the moment of inertia around 12 and the compressibility of the oil in the oil closing chamber of the boom cylinder 4, and the body 9 and the cab 10 are also vibrated. The ride comfort of the operator was significantly impaired. In the conventional hydraulic system shown in FIG. 3, the oil generated by the main pump 21 flows into the boom cylinder 4 via the flow rate adjusting valve 23 and expands and contracts. Then, the operation lever 24 is operated to open / close the flow rate adjusting valve 23 by the pilot pressure to control the expansion / contraction of the cylinder. At that time, vibration is generated. The front vibration is based on the natural vibration determined by the oil column springs in the oil chambers 4a and 4b and the front equivalent load 25. It is also possible to improve the damping performance by inserting a throttle such as an orifice in the piston 4c. However, in the case of hydraulic excavators, it is necessary to support the static load due to gravity. Therefore, even if the orifice is inserted, the entire front falls and due to the nature of the hydraulic excavator, the front part cannot be lowered. Then, this invention aims at solving the said problem.

[0004]

[Means for solving the problem]

 The present invention is a front vibration control device for a hydraulic excavator, which is provided with a vibration control device including a hydraulic control system for rapidly damping front vibrations, and the vibration control device is activated only when the hydraulic cylinder is stopped. A hydraulic damping device is installed in the hydraulic cylinder installed in the front part, and a damping device consisting of a hydraulic control system is installed in at least the boom cylinder among the hydraulic cylinders in the front part. The pressure oil is generated at 31, and the pilot operated relief valve 32 supplies a constant pressure to the servo valve 34. The operation of the servo valve 34 detects various state quantities such as front displacement, speed, acceleration and pressure. , The controller 36 calculates and outputs the control signal (u), and the servo amplifier 35 supplies the servo current (i) to the servo valve 34. And the servo valve is driven, and a switching valve 33 is set between the boom cylinder 4 and the servo valve 34 so that the vibration damping system does not work during the normal cylinder expansion and contraction operation. This is a front damping system for a hydraulic excavator in which the servo valve 34 and the cylinder 4 are connected only when the cylinder is stopped.

[0005]

[Action]

 The front damping system of the hydraulic excavator of the present invention will be described with reference to FIG. First, when the operator operates the operation lever 24 to continuously operate the boom cylinder 4, the switching valve 33 does not operate the vibration damping system, and the sensor 37 detects various state quantities such as displacement, speed, acceleration, and pressure. Keep doing. Next, when the operator judges that the length of the boom cylinder 4 has reached the target value, the operation lever 24 is returned and the boom cylinder vibrates at the same time. However, the switching valve 33 is switched by the pilot pressure, and the boom cylinder 4 and the servo valve 4 are switched. 34 is directly connected. At the same time, the servo valve 34 operates according to a command from the controller 36 via the servo amplifier 35, and operates so as to reduce the vibration of the boom cylinder 4.

[0006]

[First Embodiment] A front vibration damping system for a hydraulic excavator in which a boom cylinder is provided with a vibration damping device.

[0007]

[Second Embodiment] A front damping system for a hydraulic excavator in which a hydraulic cylinder provided at a front portion is provided with a vibration damping device using a servo valve device.

[0008]

Third Embodiment A front vibration damping system for a hydraulic excavator including a vibration damping device including a servo valve device connected to an oil chamber of a hydraulic cylinder.

[0009]

Fourth Embodiment A servo valve of a servo valve device formed by a sensor for controlling a servo valve, a controller, a servo amplifier, etc. is connected to an oil chamber of a hydraulic cylinder, and the hydraulic cylinder and the servo are connected in a circuit of the servo valve device. A switching valve is provided to enable switching of valve on / off by pilot pressure of the operating lever, a pump for supplying high-pressure oil of a constant pressure is provided to the servo valve, and a pilot pressure is driven by the switch. This is a front vibration control system for hydraulic excavators that is equipped with a relief valve that is operated by a shutoff valve.

[0010]

Fifth Embodiment A pressure oil is generated by a sub pump, a constant pressure is supplied to a servo valve by a pilot relief valve, various front state quantities such as displacement, speed, acceleration, and pressure are detected and controlled by a controller. This is a front damping system for hydraulic excavators that calculates and outputs a signal, and the servo amplifier converts the servo current to be supplied to the servo valve to drive the servo valve.

[0011]

[Sixth Embodiment] A switching valve is installed between the boom cylinder and the servo valve so that the vibration damping system does not work during normal cylinder expansion and contraction, and the switching valve connects the servo valve and the cylinder only when the cylinder is stopped. This is a front vibration control system for hydraulic excavators.

[0012]

[Embodiment 7] A front vibration damping system for a hydraulic excavator in which a relief valve is operated by a switch.

[0013]

[Embodiment 8] A front vibration damping system for a hydraulic excavator in which a vibration damping device including a hydraulic control system for rapidly damping front vibration is provided and the vibration damping device is activated only when a hydraulic cylinder is stopped. ..

[0014]

Ninth Embodiment A pressure oil is generated by the auxiliary pump 31, and a constant pressure is supplied to the servo valve 34 by the pilot operated relief valve 32. The operation of the servo valve 34 is such that various state quantities (displacement, velocity, acceleration, pressure, etc.) at the front are detected, and the controller 36 calculates and outputs the control signal (u). Convert the servo current (i) to be supplied to drive the servo valve, while preventing the damping system from operating between the boom cylinder 4 and the servo valve 34 during normal cylinder expansion and contraction operation. A switching valve 33 is installed on the hydraulic excavator so that the switching valve 33 connects the servo valve 34 and the cylinder 4 only when the cylinder is stopped, and the relief valve 32 is operated by the switch 38. It is a front damping system.

[0015]

【effect】

 The front damping system of the hydraulic excavator of the present invention rapidly attenuates the machine vibration due to the uncomfortable front vibration generated when the boom cylinder is stopped during the aerial operation of the hydraulic excavator, thereby improving the ride comfort of the operator and improving the work environment. There is an effect that can be improved. In addition, even a young operator with little experience can operate with less vibration, which is extremely advantageous in terms of occupational health. Also, by applying the front damping system of the hydraulic excavator of the present invention to the hydraulic cylinder at the front part of the conventional hydraulic excavator, the front vibration generated by the oil column spring in the oil chamber when the operation of the hydraulic cylinder is stopped can be rapidly performed. There is an effect that can be attenuated. In addition, the front vibration is based on the natural frequency determined by the oil column of the oil chamber and the load equivalent to the front, but when the vehicle is stopped, it is stopped by a vibration control device consisting of an appropriate hydraulic control system to damp that vibration. There is an effect that the generated vibration can be rapidly attenuated. In order to rapidly attenuate front vibration, the present invention has a structure in which a vibration control device using a hydraulic control system is added to a conventional hydraulic cylinder of the front part as shown in FIG. 2, and a sub pump 31 generates pressure oil, The pilot-operated relief valve 32 supplies a constant pressure to the servo valve 34, and the operation of the servo valve 34 detects various front state quantities such as displacement, speed, acceleration, and pressure, and the controller 36 controls the control signal (u ) Is calculated and output, the servo amplifier 35 converts it into a servo current (i) to be supplied to the servo valve 34, and drives the servo valve so that the normal operation is performed between the boom cylinder 4 and the servo valve 34. The switching valve 33 is installed so that the vibration damping system does not work during the cylinder expansion and contraction operation, and the switching valve 33 connects the servo valve 34 and the schilling 4 only when the cylinder is stopped. Since a hydraulic shovel of a front control system comprising so as to be, be any working conditions quickly vibration of the front portion occurring at the time of stop, and there is certainly effective, which can be attenuated. Further, the front damping system of the hydraulic excavator of the present invention was developed by taking the working environment of the operator into consideration, and the improvement of the working condition of the operator is the most important. Therefore, according to the present invention, when the operator operates the operation lever 24 to continuously operate the boom cylinder 4, the switching valve 33 does not operate the vibration damping system, and the sensor 37 causes various changes in displacement, speed, acceleration, pressure, etc. It continues to detect the state quantity. When it is determined that the length of the boom cylinder 4 has reached the operator's target value, the operation lever 24 is returned and the boom cylinder 4 vibrates at the same time, but the switching valve 33 is switched by the pilot pressure and the boom cylinder 4 and the servo valve 3 are switched. 4 are connected. At the same time, the servo valve 34 is actuated by a command from the controller 36 via the servo amplifier 35, and operates so as to damp the vibration of the boom cylinder 4. In this way, not only a skilled operator but also an operator who is not so skilled can work efficiently in a comfortable working environment and working conditions.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a vibration damping system according to a first embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram of a first embodiment of the present invention.

FIG. 3 is a hydraulic circuit diagram for driving a conventional boom cylinder.

FIG. 4 is an explanatory diagram showing a front vibration generation state in the hydraulic excavator.

[Explanation of symbols]

1 boom 14 flow control valve 23
Flow path between the oil chamber 4b and the arm 2 Arm 15 Flow path between the main pump 21 and the flow rate adjusting valve 3 Bucket 16 Flow rate adjusting valve 23
Between the tank and the tank 4 Boom cylinder 17 Flow path between the flow path 16 and the servo valve 4a Oil chamber 18 Flow path between the auxiliary pump 31 and the servo valve 4b Oil chamber 19 Transmission from the switch 38 to the relief valve 32 Road 5 Arm cylinder 6 Bucket cylinder 20 Control lever 24
To the switching valve 33 7 Strap 8 Rod 21 Main pump 9 Airframe 22 Tank 10 Cab 23 Flow rate adjusting valve 11 Traveling device 24 Operating lever 12 Foot pin 25 Front equivalent load 13 Flow rate adjusting valve 23 and oil chamber 26 Oil chamber 4a Flow path between the switching valve 33 and the switching valve 33 flow path between the switching chamber 33 and the switching valve 33 27 flow path between the oil chamber 4b and the switching valve 33 flow path between the switching valve 33 and the servo valve 34 flow between the switching valve 33 and the servo valve 34 Path 30 Signal transmission path from sensor 37 to controller 36 and servo amplifier 35 to servo valve 34 31 Sub pump 32 Pilot operated relief valve 33 Switching valve 34 Servo valve 35 Servo amplifier 36 Controller 37 Sensor 38 Switch

Claims (10)

[Scope of utility model registration request] 1. A front vibration damping system for a hydraulic excavator, comprising a hydraulic vibration damping device provided on a hydraulic cylinder arranged at a front portion. 2. The front damping system for a hydraulic excavator according to claim 1, wherein the boom cylinder is provided with a damping device. 3. A front vibration damping system for a hydraulic excavator according to claim 1, wherein a vibration damping device including a servo valve device is provided on a hydraulic cylinder arranged at a front portion. 4. The front vibration damping system for a hydraulic excavator according to claim 1, further comprising a vibration damping device including a servo valve device connected to an oil chamber of the hydraulic cylinder. 5. A servo valve of a servo valve device formed by a sensor for controlling the servo valve, a controller, a servo amplifier, etc. is connected to an oil chamber of a hydraulic silling, and the hydraulic cylinder and the servo are connected in a circuit of the servo valve device. Provided with a switching valve for switching the valve on / off by pilot pressure of the operating lever, provided with a pump for supplying high pressure oil of a constant pressure to the servo valve, and pilot operated by hydraulically applying pilot pressure by the switch. The front damping system for a hydraulic excavator according to claim 1, further comprising a relief valve. 6. A sub pump generates pressure oil, a pilot relief valve supplies a constant pressure to a servo valve, detects various front state quantities such as displacement, speed, acceleration, and pressure, and controls by a controller. 2. The front damping system for a hydraulic excavator according to claim 1, wherein a signal is calculated and output, and the servo amplifier converts the signal into a servo current to be supplied to the servo valve to drive the servo valve. 7. A switching valve is installed between the boom cylinder and the servo valve so that the vibration damping system does not work during normal cylinder expansion and contraction, and the servo valve and the cylinder are connected by the switching valve only when the cylinder is stopped. The front damping system for the hydraulic excavator according to claim 1, wherein 8. The front damping system for a hydraulic excavator according to claim 1, wherein the relief valve is actuated by a switch. 9. The front of the hydraulic excavator according to claim 1, wherein a vibration damping device including a hydraulic control system for rapidly damping front vibration is provided, and the vibration damping device is activated only when the hydraulic cylinder is stopped. Vibration control system. 10. The auxiliary pump 31 generates pressure oil, and the pilot operated relief valve 32 can supply a constant pressure to the servo valve 34. The operation of the servo valve 34 includes displacement, velocity, acceleration and pressure. Detects various state quantities at the front,
The controller 36 calculates and outputs the control signal (u), and the servo amplifier 35 converts it into the servo current (i) to be supplied to the servo valve 34 so as to drive the servo valve. On the other hand, the boom cylinder 4 A switching valve 33 is installed between the servo valve 34 and the servo valve 34 so that the vibration damping system does not work during normal cylinder expansion and contraction, and the switching valve 33 connects the servo valve 34 and the cylinder 4 only when the cylinder is stopped. The front damping system for the hydraulic excavator according to claim 1, wherein the relief valve 32 is operated by a switch 38.