Proper maintenance of bulldozers

(1) Keep the tracks at an appropriate tension

If the tension is excessive, the tension of the guide wheel spring acts on the track pin and pin sleeve, and the outer circle of the pin and the inner circle of the pin sleeve are constantly subjected to high compressive stress. During operation, the pin and pin sleeve will wear out prematurely. At the same time, the elastic force of the guide wheel tensioning spring also acts on the guide wheel shaft and shaft sleeve, generating a large surface contact stress, which makes the guide wheel shaft sleeve prone to wear into a semi-circle. The pitch of the track links is prone to elongation, which will reduce the mechanical transmission efficiency and waste the power transmitted from the engine to the drive wheels and tracks.

If the tracks are tensioned too loosely, they are prone to detaching from the guide wheels and idler wheels. Moreover, the tracks lose correct alignment, causing fluctuations, slapping and impact during operation, which leads to abnormal wear of the guide wheels and idler wheels.

The adjustment of the track tension is achieved by adding grease to the oil injector of the tensioning cylinder or discharging grease from the oil drain, and then making the adjustment in accordance with the standard clearance of each model. When the pitch of the track link is stretched to the point where a set of track links needs to be removed, the meshing surface between the drive wheel tooth surface and the pin sleeve will also be abnormally worn. At this time, appropriate treatment should be carried out before the meshing condition deteriorates, such as turning the pin and pin sleeve over, replacing the excessively worn pin and pin sleeve, and replacing the track link assembly, etc.

(2) Keep the guide wheels centered

Misalignment of the guide wheels has a significant impact on other parts of the traveling mechanism. Therefore, adjusting the gap between the guide wheel guide plate and the track frame (correcting misalignment) is a key point to extend the service life of the traveling mechanism. When adjusting, use the gasket between the guide plate and the bearing to correct. If the gap is large, remove the gasket. The gap is small. Add gaskets. The standard clearance is 0.5 to 1.0mm, and the maximum allowable clearance is 3.0mm.

(3) Turn the track pins and pin sleeves over at the appropriate time

During the wear process of the track pins and pin sleeves, the pitch of the track links is gradually elongated, resulting in poor meshing between the drive wheels and the pin sleeves, causing damage to the pin sleeves and abnormal wear of the drive wheel tooth surfaces. This can lead to snaking, slapping and impact, significantly shortening the service life of the traveling mechanism. When the pitch still cannot be restored by adjusting the tension, the track pins and pin sleeves need to be turned over to obtain the correct track pitch. There are two moments on site that determine the flipping of the track pins and pin sleeves. One method is to determine the moment when the track link is elongated by 3mm. Another method is to determine the moment when the outer diameter of the pin sleeve wears down by 3mm.

(4) Tighten the bolts and nuts in time

When the bolts of the traveling mechanism become loose, they are prone to breakage or loss, causing a series of malfunctions. During routine maintenance and repair, the following bolts should be inspected: installation bolts for the idler wheels and supporting wheels, installation bolts for the drive wheel tooth blocks, installation bolts for the track plates, installation bolts for the idler wheel guard plates, and installation bolts for the diagonal brace heads. The tightening torque of the main bolts should be referred to the manual of each model.

(5) Timely lubrication

The lubrication of the traveling mechanism is of great significance. Many idler wheel bearings "burn out" and are overcharged because oil leakage is not detected in time. It is generally believed that the following five points may cause oil leakage: Due to the poor or damaged O-ring between the retaining ring and the shaft, oil leakage occurs from the outside of the retaining ring and the shaft. Due to poor contact of the floating seal ring or defects in the O-ring, oil leakage occurs between the outer side of the retaining ring and the supporting wheels (idler wheels, guide wheels, drive wheels). Due to the poor O-ring condition between the support wheel (idler wheel, guide wheel, drive wheel) and the bushing, oil leakage occurs between the bushing and the roller. Oil leakage occurs at the filling plug due to loose filling port plugs or damaged seat holes sealed by conical plugs. Due to the poor quality of the O-ring, oil leakage occurs between the cover and the roller. Therefore, it is necessary to pay attention to checking the above-mentioned parts in daily life and add or replace them regularly according to the lubrication cycle of each part.

(6) Check for cracks

Cracks in the walking mechanism should be inspected in a timely manner, and welding repair and reinforcement should be carried out promptly.