The Reasons Influencing Walking Performance Are Briefly Discussed

- Jul 02, 2018-

Engineering vehicles, in crawler travel mechanism has to adapt to the wide roads, traction, passing ability, grounding than the small, good stability, the advantages of small turning radius and hoisting machinery, widely used, earthmoving machines and drilling machines, etc. The influence factors of caterpillar engineering vehicles to walk a lot, if not considerate, unreasonable design, there will be walking and turning difficult, poor acceleration, greatly influence on the performance of the vehicle use. The following is a brief introduction of several factors that affect the performance of tracked engineering vehicles.

To 1, in the face of crawler running resistance in the face of crawler running resistance refers to the ground deformation caused by the running resistance, its size and the ground pressure, caterpillar centroid position and ground conditions and other factors. Owing to bad engineering vehicles is typically in comparison of construction work on the ground, so in operation than the drag coefficient of choice, should give full consideration to the various work environment, select suitable resistance coefficient. For some more common road conditions, the drag coefficient of muddy land, fine sand soil and cultivated land is *.

2. The internal resistance mainly refers to the resistance caused by the friction within the walking mechanism. The general crawler walking mechanism is composed of driving mechanism, crawler, supporting wheel, guiding wheel, supporting chain wheel or supporting chain plate. Videotapes, friction between these institutions will produce certain internal resistance, the resistance mainly consists of five parts: (1) general segments to bypass the guide wheel and the drive wheels, track pin to track pin sleeve when the relative rotation of friction resistance. This resistance is related to the diameter of the track pin, the friction coefficient between the track pin and the pin sleeve. (2) friction resistance at the supporting heavy wheel. This resistance is related to the external diameter of the supporting wheel, the diameter of the supporting wheel, the gravity of the supporting wheel to the track plate and the friction coefficient between the supporting wheel and the axle. (3) friction resistance at the guide wheel. This resistance is related to friction coefficient between guide wheel shaft and bearing, guide wheel shaft diameter and guide wheel raceway diameter. (4) friction resistance at the driving wheel. This resistance is related to the friction coefficient of the drive wheel bearing, the diameter of the drive wheel shaft, the diameter of the drive wheel knuckle circle and the tension of the track belt. (5) friction resistance at sprocket or sprocket. This resistance is mainly related to the weight, contact area and friction coefficient of the crawler board supported by sprocket or sprocket. The internal resistance generally accounts for about 16% of the walking resistance, so full consideration should be given to the design

3. The slope resistance refers to the walking resistance caused by the component of self-weight when the vehicle climbs the slope. The general construction site is convex and concave, which requires the tracked project vehicle must have a certain ability to climb the slope. The formula of slope resistance is F= mgsina. It can be seen that the magnitude of slope resistance is mainly determined by the vehicle's slope and self-weight, and is proportional to both. This resistance generally accounts for about 60% of the total driving resistance, which is the main factor affecting the driving performance of tracked engineering vehicles.

4. Turning resistance there are two main types of turning resistance :(1) in situ turning resistance. In situ turning resistance refers to the resistance generated when both tracks turn in reverse at the same time, which is mainly related to the ratio coefficient of vertical load and friction resistance, the length of track ground and track distance. (2) steering resistance of single track. The steering resistance of single track refers to the resistance caused by braking on one side of track and turning on the other side. This resistance is mainly related to flow resistance coefficient, steering resistance coefficient, track length and track distance. In addition, both the size of the resistance is also associated with the center of mass of the vehicle, if mechanical centroid fall in the center of the crawler frame (both caterpillar earth pressure distribution), then turning resistance than caterpillar grounding than the non-uniform distribution of smaller, so should try to make the vehicle mass center when turning on the center of the crawler frame.

5. The size of wind resistance is mainly related to the windward area, structural filling rate and wind speed of the vehicle. For medium - and large-sized tracked engineering vehicles, wind resistance generally accounts for only 0.1% of the traction force because of its large traction force. Therefore, wind resistance can only be used as a reference factor.

6. Inertia resistance. Inertial resistance is the walking resistance caused by the acceleration of the vehicle when starting, and its size is mainly related to the self-weight and starting acceleration, and is proportional to it. This factor can also be used as a reference for some engineering vehicles with slow speed and no need for quick start.