Application of steel cord for rubber vibration damping track on bulldozer

Energy saving and environmental protection has become an important research content. Compared with ordinary vehicles, the noise of construction machinery is more serious to the environment pollution. Therefore, how to effectively control the engineering mechanical noise has become an important factor to enhance the competitiveness of domestic products

Along with the technical progress of construction machinery, energy saving and environmental protection has become an important research content. Compared with ordinary vehicles, the noise of construction machinery is more serious to the environment pollution. Therefore, how to effectively control the engineering mechanical noise has become an important factor to enhance the competitiveness of domestic products.

1 crawler type bulldozer noise generation and transmission mode

As shown in Figure 1, according to the mechanism of bulldozer noise generation and propagation, track steel cord can put the noise control techniques are classified into the following three categories: Figure 1 bulldozer noise generation and propagation mechanism is the source of the noise control; the second is the control of noise transmission path; the third is the protection to the noise receiver. Control of noise source is one of the most basic, the most direct measures, including reduce noise excitation force and reduce engine parts of exciting force response, namely, the transformation vibration source and sound source. But when it is difficult to control the source of noise, we need to take measures in the noise of the transmission channels, such as sound absorption, sound insulation, noise elimination, vibration and vibration isolation and other measures.

图1 推土机噪声产生和传播的机理

2 Properties of rubber

A rubber is a viscoelastic material, is a kind of high molecular polymer. When the external force is subjected to an external force, the compression, the dislocation and the relaxation of the molecular chain of the polymer material form a network, which can be used for increasing the damping of the mechanical structure. Rubber materials because of both viscous liquid and elastic solid characteristics, so its mechanical properties are also between the two. When an alternative load is applied to the elastic material, the stress and strain in the material increase or decrease almost at the same time, both of which are close to the same.

3 rubber vibration reduction in bulldozer application

(1) the application of the engine

At present, there are many kinds of engine vibration cushion, and the rubber vibration pad has the advantages of small size, low cost and easy to adjust the elasticity and stiffness, and it has been widely used in the field of engine vibration and noise reduction. Therefore, the current bulldozer diesel engine supports almost all of the use of damping rubber.

In support of parts of the use of rubber, high interface requirements, and also pay attention to high temperature and is not affected by the erosion of oil. Not only pay attention to the diesel engine rotates at a high speed, the vibration isolation, and the diesel engine idling and start and stop when the vibration isolation and prevent the resonance of the parts of the body should pay full attention to.

Figure 2 is a high power diesel engine used rubber bearing sample, the power of diesel engine for 735 kW, the quality of 5.7 T, supported by 4 points in the frame, each rubber support shape as shown in Figure 3 is surface bonding rubber oil resistance. Rubber bearing itself with an angle of 30 degrees layout, removing diesel engine, removed from the engine side foot and body side between the level, loaded diesel engine, diesel engine body and a level.

(2) the application effect on the wheel track guiding to a crawler type bulldozer steering wheel mounted rubber vibration damper as an example, figure 4 shows the installation position of the rubber shock absorber, figure 5 said its shape, from the figure visible, its shape looks like a wedge "sandwich", the role is on the vertical straight and two horizontal directions can be to buffer role.

Vibration damping rubber working temperature: -30~60 degrees C; the maximum amplitude of vibration load: 270 kN; load frequency: Hz 012~200; the frequency of the main load: Hz 4~8. For small amplitude vibration load, the vibration absorber can absorb more than 80% of the vibration energy; while for the impact load, it can be more than 50% of the impact energy dissipation.

(3) the application of the bulldozer suspension mechanism

Hebei Xuanhua Engineering Machinery Co., Ltd production of the SD8 and PR series overhead driving crawler bulldozer installed rubber suspension mechanism (see Figure 6), walking system adopts the elastic suspension device, easy to guide wheel over obstacles and continuous vice hanging device can through the floating effect close to the ground running. Buffer device absorbing impact on the ground, reduce the chassis is about 50% of the impact load is transmitted, to improve the stability of the walking machine and the driver's comfort, increase the track and ground contact area increased (about 15%), improve the machine traction. Walking frame and the frame hinged by pivot replaces the traditional character beam structure, improve the frame and the frame connection stiffness.

The vibration and noise of a bulldozer with a rubber suspension is greatly reduced. The practice has proved that the rubber suspension device is suitable for the operation in harsh environment, the suspension device has reliable performance, durability, low price and convenient replacement. So the damping buffer structure is expected to be the main structure of the vibration and noise reduction mechanism of the bulldozer.