Key hints: the method of vibration reduction and maintenance of engineering machinery engine: engine is the main source of vibration of engineering machinery, taking some effective methods to reduce vibration, it can greatly improve the driver's comfort, and also has a great help for the extension of machine life.
Engine is the main vibration source of engineering machinery. Some effective methods to reduce vibration can greatly improve the driver's comfort, and it also has a great help for the extension of machine life.
1. Vibration source control
The vibration source control runs through the whole process of design, manufacture and use, which is embodied in improving the balance performance of the engine, dynamic performance, processing and assembly precision of parts. There are various forms of engine vibration in the work. The main reasons are: the periodic movement of the engine center of gravity, the inertia force acting along the cylinder up and down, all the centrifugal inertia forces of the rotating parts, and the rotation of the crankshaft by the alternating action of the gas pressure. These unbalanced forces and moments can be used to adjust the natural frequency of the system by changing the design parameters of the engine to avoid structural resonance and to improve the resonance characteristics of the system, such as the modal analysis of the body and the finite element calculation to study the vibration modes of the natural frequency of the body. In order to weaken the vibration source and avoid resonance, it should be considered from the design stage. It is necessary to run through the system engineering idea in the whole design and fully apply modern design methods, such as the design of finite source, reliability design, robust design, optimization design, computer aided design, and intelligent system and expert system design.
Two. Isolation of vibration
1. Rubber isolation
The traditional engine adopts elastic support to reduce vibration, and the isolation device has simple structure, low cost and reliable performance. Rubber bearings are usually mounted on the frame. They are divided into compression type, shear type and compression shear type according to the force. The compression type is simple in structure, easy to manufacture and widely used, and is usually limited to vertical direction because of its high natural frequency. The shear type self vibration frequency is low, but the strength is not high. The compression shear composite type combines the advantages of the above two structures to meet the requirements of durability and reliability, which is the most widely used at home and abroad. In order to make the vibration isolation rubber support system have better damping performance, the parameter table requires the same constant spring constant, which also reduces the number of dimensions.
2, spiral wire rope isolation
As a damping element, wire rope has the performance of variable frequency parameters with low frequency and large damping and high frequency and low stiffness. Therefore, it can effectively reduce the vibration of the body. Compared with the traditional rubber damping source, it has the advantages of oil resistance, corrosion resistance, temperature tolerance, high temperature resistance, aging resistance and small volume. The vibration isolation effect mainly depends on its nonlinear hysteresis characteristics.
3, hydraulic vibration isolation
The hydraulic support system is a structure composed of the traditional rubber bearing and the hydraulic damping. It can provide large damping in the low frequency range, and quickly attenuates the vibration of the engine. It has a lower dynamic stiffness in the middle and high frequency, and can effectively reduce the vibration and dryness of the cab.
Three. Control of engine vibration of engineering machinery
Sometimes resonance can not be avoided in engineering. Therefore, damping is often augment or vibration absorbers are reduced by dynamic vibration absorbers. The dynamic vibration absorber belongs to the control of the squeezing band, and the viscoelastic damping material has high energy loss. When the vibration is transmitted to the damping material, the deformation of tensile, bending and shearing is produced inside the material, which consumes a lot of vibration energy and attenuates the vibration. The main advantage of damping technology is that it does not need to change the original structure, does not need to add auxiliary equipment, does not need external energy and takes up less effective space. It is a promising vibration and noise reduction measure. The new product of "Xiamen Liteng Engineering Machinery Co., Ltd" in Fujian, the new product LT968 wheel loader, first adopts the dynamic vibration absorber on the selection of shock absorber, and uses the new technology to achieve the ideal vibration and noise reduction effect.
