According to China Hafnium, with the widespread popularity of wheeled tractors, crawler tractors have become more and more unfamiliar to many domestic users. However, in the actual use of farmland operations, in recent years, the return of crawler machinery has gradually emerged. This change is more due to some irreplaceable advantages of crawler tractors compared with wheeled tractors.
1. Traction force and traction efficiency
Crawler tractors have higher adhesion and greater traction than wheeled tractors. Under the same machine weight, the traction force of a crawler tractor is 1.4-1.8 times that of a wheeled tractor. The actual test: the 140-horsepower C1402 track tractor is 1.3 times that of the 180-horsepower 1804 wheel tractor (the 1804 machine is 400 kg heavier than the 1402 machine).
In terms of traction efficiency, theoretically, the traction efficiency of wheeled tractors is 55-65%, and that of crawler tractors can reach 70-80%. That is to say, for tractors with the same horsepower, the effective power of wheel tractor engines will lose 15% more than that of crawler tractors. The test shows that on hard ground and cultivated land, the traction performance of crawler tractors and four-wheel drive wheeled tractors is compared under similar conditions, and the traction efficiency of crawler tractors is about 10-20% higher. Generally speaking, 85 or 90 horsepower crawler tractors can It is used as a wheel tow with more than 100 horsepower.
2. Ground specific pressure, adhesion and influence on soil structure
Tracked tractors have a lower ground pressure ratio. The ground specific pressure of various types of crawler tractors from 51.5kW to 132kW is 44.7-53kPa, while the ground specific pressure of wheeled tractors of the same power level is much higher, resulting in poor tire adhesion and high slip rate. Take the 95.6 kW tractor as an example: the specific grounding pressure of Dongfanghong C1302 crawler tractor (with bulldozer installed) is 47.7kPa, while the grounding specific pressure of a wheeled tractor with the same horsepower range is about 104 kPa, equivalent to twice that of a crawler tractor many. According to the test, when the high-power wheeled tractor is matched with the five plow, the slip rate is generally 10-20% when the average moisture content of the soil is 30%, the firmness is 0.3MPa, and the forward speed of the unit is about 7.2km/h. , some up to 25%.
The ground pressure of wheeled tractors is high. When plowing, the rear wheels always walk in the furrow, and the shearing effect of the tires on the soil destroys the soil structure of the plow layer. After several years of cultivation, a hard bottom layer will be formed under the plow layer of the soil, which is not conducive to the storage of water and moisture in the soil and the growth of crops. Even after deep raking, small compacted lumps will remain and the microstructure of the soil will be destroyed. In addition, in farms in central Henan and farming surveys in Northwest China, it was found that the deep grooves rolled by the rear wheels of wheeled tractors caused inconsistencies in seed sowing depth and covering soil, which had a very negative impact on the quality of sowing. And also bring difficulty to follow-up watering operation.
Tests have shown that the emergence rate of arable land is only 30%-40% after being compacted by wheel tows, while the emergence rate can still reach 80%-90% after being compacted by shoes. The grounding ratio of crawler tractors is lower than that of wheeled tractors, and the degree of compaction to the soil is smaller than that of wheeled tractors. The effect of deep plowing and intensive cultivation is particularly prominent, which makes crawler tractors have obvious advantages in low and wet land operations. Use wheel tow.
3. Operation efficiency, operation environment and operation quality
When tractors are working on farmland, the speed of rotary tillage is generally 5-6km/h, the speed of plowing is generally 7-9km/h, and the speed of harrowing is generally 10-12km/h. At present, the farming gear speed of crawler trailers is equivalent to that of wheel trailers. Whether it is plowing, harrowing, sowing and other farmland operations, shoe trailers are not slower than wheel trailers, and the traction advantage is very obvious. For example, when the C1802 crawler tractor is used for field tests, it can drive a 6.5m heavy harrow, while the wheel tractor with the same power can only drive a 5.3m heavy harrow. The operation efficiency of crawler towing is obviously higher.
Due to the low center of gravity and large adhesion coefficient, crawler tractors have good slope stability against overturning and sliding, and also have the characteristics of maneuverability with small turning radius and strong off-road capability of climbing ability. It has better adaptability than wheeled tractors for heavy-duty planting operations and terraced field operations such as heavy sticky land and land reclamation operations. Especially in hilly areas, the slope of cultivated land is relatively large, and the soil resistance is uneven, resulting in poor stability, unsafety, uneven operation depth and low operation quality of wheeled tractors when operating on slopes. Farmers choose crawler tractors for plowing, plowing, and harrowing. Ground work will significantly improve the quality of work.
Crawler tractors are also particularly suitable for farming under harsh soil conditions, especially in field operations in early spring when the soil is not thawed. Generally speaking, crawler tractors can go to the ground 2-3 days earlier than wheel tractors, which is convenient for farming. After equipped with rubber crawlers, the crawler tractor can also drive on the road, which is more of an all-terrain working machine.
4. Utilization rate and maintenance convenience
In addition to field operations, crawler tractors can also play a role in farmland infrastructure and small water conservancy projects. If a shovel is installed, it can be used as a bulldozer in agricultural earthworks such as ditching, cleaning fish ponds, and changing slopes to ladders. The comprehensive utilization rate is higher than that of wheeled tractors. Moreover, the full frame structure of the crawler tractor, compared with the frameless structure of the wheel tractor, does not need to be broken and disassembled like a wheel tractor during maintenance, which greatly facilitates the daily repair and maintenance of the whole machine by users.
5. Economy and price comparison
The farmland operation test shows that the 120/140 horsepower crawler trailer with the same weight can be used as a 160/180 horsepower wheel trailer, but the fuel consumption is greatly reduced (it can save more than 25% of fuel), and the economic benefits are obvious. At the same time, in terms of selling price, the sales price of the 140-horsepower C1402 track trailer with the same operating capacity is about 250,000 yuan, while the price of the 180-horsepower 1804 wheel trailer is about 420,000 yuan, with a price difference of nearly 70%. Compared with the 1604 wheeled trailer, the C1202 shoe trailer costs about 200,000 yuan, and the wheeled trailer costs about 380,000 yuan, which is nearly twice as expensive. The cost performance of wheeled trailers and shoe trailers is obvious.