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Improvement of track rollers on track chassis--Fujian

by:Laike     2020-07-16
After the first batch of crawler chassis delivered by our company to foreign users, the friction of the rollers was too large, the seals were easily damaged, the chassis was heavy, and the useless power consumption was large. --Fujian Supporting Wheel

The running speed of crawler chassis construction machinery is generally lower than 5??km/h, and its driving function is only used when short-distance transitions and moving working positions. If it moves for a long distance, it should be transported by trailer. The crawler chassis ordered by this foreign user is mainly used for non-road transportation machinery, and its driving speed is up to 12?km/h, and the operation is only its auxiliary function. The track roller selected for this track chassis is heavy-duty and of great quality. The track roller is a copper sleeve type sliding bearing, and the seal is a floating oil seal

The analysis believes that due to the higher driving speed of the chassis, the line speed of the floating oil seal on the track roller exceeds the design, which causes the floating oil seal to heat up. The heating of the floating oil seal not only causes the rapid aging of the O-ring and the decrease of the sealing effect, but also causes the increase of the axial pressure and the increase of the friction resistance of the roller. In addition, the copper sleeves of its rollers will also wear due to increased linear speed and poor lubrication. --Fujian Supporting Wheel

In response to the above problems, we carried out the first structural improvement of its rollers (see Figure 1). The method is as follows: the sliding bearing (copper sleeve) is changed to a rolling bearing to adapt to higher speeds; to reduce quality and simplify processing The process is to change the wheel body from forging to casting (the bearing capacity is slightly reduced); the diameter of the floating oil seal is reduced, so that the linear speed of the floating oil seal is within the allowable value to reduce heat generation.

After the rollers are improved, the rotational resistance they receive is reduced, but because the old floating oil seal is still used, the rotational resistance is still very large. In order to reduce the rotation resistance of the roller, it was decided to replace the appropriate oil seal. --Fujian Supporting Wheel

After inquiry, a special combination oil seal was finally found (see partial view in Figure 2). The combined oil seals are made of nitrile rubber, and its inner diameter is lined with L-shaped stainless steel lining. There are 2 lips in the axial direction and 3 lips in the radial direction. The cavity formed by the L-shaped stainless steel lining and the lips is used for filling grease.

After the combined oil seal is installed in place, its outer diameter is in interference fit with the wheel housing bearing hole, and its L-shaped stainless steel lining is also in interference fit with the roller axle. When the roller is rotating, the rotating part of the combined oil seal is inside it, that is, between the L-shaped stainless steel lining and the lips. The test results show that the combined oil seal has a good sealing effect, and the rotational friction is reduced to 1/3 before improvement. --Fujian Supporting Wheel

The improved track roller has the advantages of simple structure, low manufacturing cost, light weight, good sealing effect, convenient lubrication and long service life, and can meet the requirements of users for driving speed. Later, we changed the track roller to the welded structure of the stamped wheel body and the bearing housing, and its quality was further reduced. The improved crawler chassis has been used by users for more than one year in rainforest and mountain conditions, and no previous problems have occurred, which proves the success of this improvement.
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