Vibration and noise are two major hazards when the loader works. The engine is a major source of vibration loader. The vibration not only affects the engine itself, but the transmission of vibration directly affects the reliability and service life of the loader. At the same time, the ride comfort of the driver becomes poor, reducing the driver's the work efficiency. Main reason for the loader vibration is the rotation of the loader's rotating parts. The periodical change of gas pressure inside the engine cylinder and a periodic change of moving parts make vibration and engine crankshaft system vibrate. External forces also cause the loader to vibrate. For example, loading changes are caused by loader shoveling and unloading, the road is rough when the loader is driving, the change of speed and direction of motion cause a sudden change in the size and direction of the earth's force on the tire, etc. Therefore, some effective methods must be adopted to reduce vibration.
First, it can be suppressed from parameter selection.
It is the reason why the wheel loader vibrates during driving that the natural vibration frequency of the vehicle body is within the range of the interference frequency caused by the unevenness of the road surface. In order to avoid resonance, the vibration characteristic of the vehicle body is calculated in the design, so that the vibration frequency of the vehicle body is not within the range of interference frequency caused by the road surface. It is found that the interference frequency of the road surface is proportional to the speed of driving and inversely proportional to the undulating wavelength of the road surface. The average wavelength range of the road surface is determined by a large number of measurements, and the interference frequency caused by different speeds is limited to a small range. In the design, the wheelbase should be increased as much as possible. Optimized structure and materials should be adopted to reduce the quality of the whole machine. The distributed mass is as close as possible to the vehicle's centroid, so that the moment of inertia around the centroid is small. In addition, a more ideal loader tire with large damping coefficient and small elastic coefficient should be chosen.
Second, vibration isolation measures can be taken.
First, rubber isolation can be chosen. Rubber damping blocks are added to the multi-point support used in the installation of loader engine and rear frame. On the one hand, the elastic vibration of the rubber damping block cushioned the vibration of the engine itself, making it transmitted to the rear frame as little as possible. On the other hand, it also cushioned the vibration of the frame, allowing it to pass as little as possible to the engine. The rubber conical support system is adopted. The vibration isolation device has simple structure, low cost and reliable performance. The rubber support is generally installed on the rear frame of the loader, which can be divided into compression type, shear type and compression-shear type according to the stress. Compression type is simple in structure, easy to manufacture, widely used, and generally limited to vertical direction due to high frequency of self-vibration. Natural frequency of sheers' vibration is low, but the intensity is not high. Compression-shear compound type combines the advantages of the two structures to meet the requirements of durability and reliability. Compression-shear compound type is the most widely used rubber vibration isolation in China. In order to make the vibration reduction performance of the vibration isolation rubber support system better, the spring constant in the same direction needs to stay the same. When the stiffness is strengthened in other directions, steel plate can be added into the rubber to change the compression-shear spring constant. This can also reduce the appearance size.
Secondly, you can choose steel wire rope vibration isolation. As a vibration damping component, the steel wire rope has the properties of low frequency large damping, high frequency low stiffness and variable parameters, so it can effectively reduce the vibration. Compared with the traditional rubber shock absorber, wire rope vibration isolator has the advantages of anti-oil, anti-corrosion, anti-temperature difference, anti-high temperature, anti-aging and small volume. The vibration isolation effect mainly depends on its nonlinear hysteresis characteristics. The acceleration transfer rate of wire rope vibration isolator is related to frequency. Even in the case of resonance, the acceleration transfer rate of wire rope vibration isolator is less than 1. Therefore, the use of wire rope vibration isolator can effectively inhibit resonance. When the external excitation frequency is close to the natural frequency of the vibration isolator, steel wire rope vibration isolator gradually becomes soft, making natural frequency be away from the excitation frequency. Wire rope vibration isolator automatically changes the natural frequency to avoid resonance.
With the continuous improvement of people's requirements for the performance of the loader, the traditional vibration damping technology is increasingly unable to meet the requirements, so it is imperative to adopt new vibration damping technology. On the one hand, loader products should continue to apply modern design methods and means, use advanced manufacturing technology and improve the level of the design and manufacture of engine, so as to reduce or eliminate the harmful vibration in the engine's work. On the other hand, we adopt engine vibration isolation system with effective control and reasonable cost, making its full play. Thus it can reduce the influence of engine vibration on the performance of the loader and improve the reliability, comfort and operating efficiency of the loader. In this way, we can and improve the competitiveness of products in the market.