The steering bearing of three wheeled agricultural vehicle mainly adopts tapered roller bearing, thrust ball bearing and thrust angular contact ball bearing

The front fork of the Three-wheel agricultural vehicle mainly bears a large axial impact load and a relatively small radial load. In addition, the flexible steering requires that the steering bearing can bear both a large axial impact force and a certain radial force with a small friction torque. Limited by the cost and space structure, the steering bearing mainly adopts three types: tapered roller bearing, thrust ball bearing and thrust angular contact ball bearing. The main specifications and models are as follows (the original code is in brackets).

Tapered roller bearing 30205 (7205 E) 30206 (7206 E)

Thrust ball bearing 51107 (8107) 51108 (8108) 51109 (8109) 51109 a 51206 (8206) 51209 (8209)

Thrust angular contact ball bearing 668709, 668909, 91680709, 768905, 768906, 698709,  698909, 698908, 698706, 698709A, 698909A

Tapered roller bearings are mainly used to bear the combined radial and axial loads dominated by radial loads. Generally, they should not bear the axial loads alone. The axial clearance of this kind of bearing has a great influence on the normal operation of the bearing. When the bearing clearance is too small, the steering resistance is large; When the axial clearance is too large, the bearing is easy to be damaged. The use of this kind of bearing in three wheel agricultural transport vehicles shows large steering resistance, easy to get stuck, and affects the driving safety. At present, three wheel agricultural transport vehicles rarely use this type of bearing.

The thrust ball bearing can only bear axial load in one direction, not radial load. As the axial load is evenly distributed on each steel ball, the load capacity is large. This type of bearing is often used in combination with deep groove ball bearing in the steering of three wheel agricultural transport vehicles, which is complex to install and has high cost. If only thrust ball bearings are used, the bearings will be prematurely damaged due to uneven load because they can not bear radial force. Some three wheeled agricultural vehicles use this type of bearings, which has poor reliability and is prone to failure.

The thrust angular contact ball bearing can bear the combined radial and axial load dominated by axial load. This type of steering bearing is used in the three wheeled agricultural transport vehicle, which has the most suitable stress mode, large rigidity and small steering resistance Most three wheeled agricultural vehicles use this type of bearing, which has high reliability and low failure rate. Compared with thrust ball bearings, the price is slightly higher. There are some differences among several commonly used bearing structures 6687009 and 668909 are steering bearings used in the early stage. The shaft ring is separated from the seat ring and is fully loaded with steel balls, which is not convenient for assembly. Because there is a grinding wheel over travel groove at the outer circle and end face at the seat ring step, stress concentration is easy to occur during quenching, and it is easy to be broken during assembly and use 6957009 and 698909 use an outer dust cover to integrate the shaft ring, seat ring and steel ball into an assembly unit, which is suitable for the production of assembly line. 698709a and 698909a are reinforced types of 6987009 and 6989009, with stronger bearing capacity and longer service life. They are new products in steering bearings. 6989008, 6987006 and 768905 are steering bearings used on small tonnage three wheel agricultural transport vehicles. 9168709 and 768906 have the same internal and external diameter as 51209 and 51206. The assembly height is slightly higher and the bearing mode is more reasonable. There are no small steps and grinding wheel over travel grooves. The three wheel agricultural transport vehicles with 9168709 as steering bearings have no faults in use, However, due to the separation of shaft ring, seat ring and cage, the assembly is slightly more difficult.

From the above analysis, it can be said that thrust angular contact ball bearings are suitable for the steering bearings of three wheeled agricultural vehicles. Now the most commonly used are 6987009, 698909 and 698709a, 698909a. The most suitable structural type is 9168709 without steps.

More about WSW tapered roller bearing and thrust ball bearing:

WSW Tapered roller bearings feature a cup and cone assembly. The cup is comprised of the outer ring and the cone assembly consists of inner ring, rollers, and cage. This bearing construction accommodates combined loads and provides low friction during operation. By adjusting one single row tapered roller bearing against a second tapered roller bearing and applying a preload, a rigid bearing application can be achieved.

The thrust ball bearing adopts the design that can bear the thrust load during high-speed operation, and is composed of washer like ferrule with ball rolling raceway groove. Because the ferrule is cushion shaped, the thrust ball bearing is divided into two types: flat bottom cushion type and self-aligning spherical cushion type. In addition, the bearing can bear axial load, but can not bear radial load.