# Thread: Problem with Pivot Bearings

1. ## Problem with Pivot Bearings

Hello All,

As you can see in figure 0, a standard pivot bearing assembly is shown. A shaft is been suspended between 2 small ball bearings. During assembling, the ball bearings are screwed towards the shaft (by a screw driver manually).
As you can see in figure 1,you can sense that due to manual screwing of ball bearings, uneven clearance is incorporated (C1 & C2) in the assembly.
So, when a Force F1 comes from left, the shaft will be shifted to right side and vice versa. You can see it clearly in figure 2. This shaft shifting pattern will be uneven because of the fact that the clearance (C1 & C2) is UNEVEN. In other words, this abrupt shaft shifting problem is called as ENPLAY.

So, we have to find out some way to the problem…THE ENDPLAY Problem.

Need your comments & any trick to screw these bearings which will solve the problem of ENDPLAY.

2. Would it be practical to preload the assembly, possibly with a wave spring or Belleville spring/washer?

Just a thought.

Dick Z

3. But in what accuracy a beliivele spring can position the bearings...??

4. Preload one bearing from one side toward a fixed bearing on the opposite side. The axial position accuracy will be determined by the fixed bearing.

Dick Z

5. Won't it be helpful, if we clamp the pivot bearings with Wrenches...

...So, the pressure will be even from bothe sides

6. Kinda like hitting your finger with a hammer. The force is applied on one side, but the results are felt on both sides. Sharing the pain as a result of the applied force.LOL

This is an example of equal and opposite reaction.

You can apply the force from one side with one screw. Two screws would aid in adjusting the axial location of the shaft, but the force would be shared on each end with either method.

Dick Z

7. But how should we hold the bellievele washer...Should I attach BELLIEVELE WASHER to a SPRING so that the Spring keeps Washer by preloading the SHAFT neatly.

Thk

8. A Belleville washer is a spring. It is "cupped", that is convex on one side, concave on the opposite side. The material, thickness, temper and size determine the "springiness" of the washer.

Another type of spring is the wave spring washer. You might look up Smalley Springs.

Dick Z

9. hI,

tHK

As you can see in the figure, a moving element is been suspended on a shaft. The Belleville Washer is been fixed to a PART. Threading is being provided on the shaft as well on the PART. By moving the PART, the BELLIVILLE Washer will contact the MOVING ELEMENT & Preload it properly.

Also if at some point of time, if the Washer wears out, then the washer will automatically expand (due to spring action ) & compensate for the SIDE PLAY Problem.

Am I right?

Thk