IMPROVING THE MAINTENANCE OF CHAIN TRANSMISSIONS FOR AGRICULTURAL PURPOSES
The article presents differentiated rates for recommended ultimate lengthening of the main standard drive chains for agricultural purposes, depending on the number of teeth of the largest chain sprocket. It has been established that in the most common range of the number of teeth, the proposed rejection rates are 2-4 times higher than the current rate of 3% for roller chains. It follows from this that such an ultimate lengthening of the chain pitch will require its corresponding device and the device of its tension element, as well as the procedure for its maintenance. There has been described the mechanism of operation of tension sprockets and the causes of their occurrence in the chain drive. There has been outlined the procedure for position adjusting of the tension sprockets, which can smooth out additional cyclic loads in the chain circuit. It has also been established that the displacement of the sprockets in one plane leads to a number of negative phenomena. There is no method for controlling displacement using a conventional ruler, so the article proposes to control it using a special gauge ruler, made in the shape of a square tube with different slots on the sides. There has been described a technique for its application. The article presents the results of field tests whose purpose was to confirm the efficient use of the gauge ruler and the issues related to lubrication and storage of chains in the wintertime. The wear of the pins of the chain transmission, adjusted using a gauge ruler, was uniform over the entire working surface and amounted to 0,047 mm, which confirms the effectiveness of its application. The tests also established that storage requires the application of refractory indelible lubricants, while the use of lubricants should not be recommended in the process of operation in a highly dusty zone. According to test results it was found that the pins of the lubricated chain transmission are worn out by 20% more than those of the non-lubricated one.