Vibration Reduction Methods For Engineering Machinery Engines

Vibration and noise are two major public hazards when construction machinery is working. The engine is the main vibration source of engineering machinery. The propagation of engine vibration directly affects the overall reliability and service life of engineering machinery. It also worsens the driver’s riding comfort and reduces work efficiency. Some effective methods must be taken to reduce vibration.

1. Vibration source control

Vibration source control runs through the entire process of design, manufacturing and even use, and is reflected in improvements such as engine balance performance, dynamic performance, and parts processing and assembly accuracy. There are various forms of vibration generated by the engine during operation. The main reasons are: the periodic movement of the center of gravity of the engine, the inertia force acting up and down along the cylinder of the reciprocating parts, the centrifugal inertia force of all rotating parts, and the alternating action of gas pressure causing the crankshaft rotation period. changes etc. These unbalanced forces and moments can usually be adjusted by changing the engine design parameters to adjust the natural frequency of the system to avoid structural resonance and improve the system resonance characteristics. For example, through modal analysis and finite element calculation of the airframe to study the mode shape of the natural frequency of the airframe. wait. Weakening machine vibration sources and avoiding resonance should first be considered at the design stage. Systems engineering thinking should be integrated into the overall design, and modern design methods should be fully applied, such as finite source design, reliability design, robust design, optimization design, computer-aided design and intelligent systems. and expert system design.

2. Vibration isolation

(1.) Rubber vibration isolation

Traditional engines use elastic supports to reduce vibration. The vibration isolation device has a simple structure, low cost and reliable performance. Rubber bearings are generally installed on the frame and are divided into compression type, shear type and compression-shear composite type according to the force conditions. The compression type has a simple structure, is easy to manufacture, and is widely used. Due to its high natural frequency, it is generally limited to use in the vertical direction. The shear type natural vibration frequency is lower, but the intensity is not high. The compression-shear composite type combines the advantages of the previous two structures to meet durability and reliability requirements. It is currently the most widely used at home and abroad. In order to make the vibration isolation rubber support system have better vibration damping performance, the parameter table requires spring constants in the same direction, which can also reduce the geometry size.

(2. )Spiral wire rope vibration isolation

As a vibration damping element, the steel wire rope has variable parameter performance of low frequency, large damping, high frequency and low stiffness, so it can effectively reduce the vibration of the machine body. Compared with traditional rubber vibration damping sources, it has the advantages of oil resistance, corrosion resistance, temperature difference resistance, high temperature resistance, aging resistance and small size. The vibration isolation effect mainly depends on its nonlinear hysteresis characteristics.

(3. )Hydraulic vibration isolation

The hydraulic support system is a structure that integrates traditional rubber supports and hydraulic damping. It can provide large damping in the low frequency range, quickly attenuate the large amplitude vibration of the engine, and has low dynamic stiffness and energy at medium and high frequencies. Effectively reduce vibration and noise in the cab.

3. Control of vibration of engineering machinery engines

Sometimes resonance cannot be avoided in engineering. Therefore, it is common to increase system damping or use dynamic vibration absorbers to reduce vibration response. The dynamic vibration absorber belongs to the frequency band control. The use of viscoelastic damping material has high energy loss. When the vibration is transmitted to the damping material, stretching, bending, shearing and other deformations will occur inside the material, thus consuming a large amount of vibration energy, causing the Vibration attenuation. The main advantages of using damping technology to reduce vibration are that there is no need to change the original structure, no need to add auxiliary equipment, no need for external energy, and less effective space occupied. It is a promising measure for vibration reduction and noise reduction. The new product 955A wheel loader produced by Zhengzhou “Yutong Heavy Industry” is the first to use this kind of dynamic shock absorber in the selection of shock absorbers, using new technologies to achieve ideal vibration and noise reduction effects.