The methods for testing the raceway diameters of turntable bearings

How to further reduce the errors in measuring the deep groove ball raceway diameter? Below we’ll introduce two methods for testing the diameters of the raceway of  four point contact  ball turntable bearings. Each method of testing has its own pros and cons.

Indirect rolling ball testing

Method to implement:

First choose a steel ball whose diameter matching the deep groove ball raceway. Put it into the deep groove ball raceway. Use the micrometer to measure the thickness of the wall between the position of the maximum diameter of the steel ball and the diameter of  the top of the inner ring gear of the four point contact ball bearing. By measuring the wall thickness of the steel ball, we can calculate the diameters of the groove. Usually use the reverse-calculation method: according to the required diameter of the deep groove raceway, we can reverse-calculate the wall thickness of the steel ball. In manufacturing process, we only need to control the steel ball wall thickness. This method is relatively straightforward, convenient.

1.Analysis of advantages and weakness of this method

Advantages:

The ease of use of the testing tools.

Weakness:

Relatively high requirements for the talents and experience of the testing personnel.

When the deep groove raceway has a relatively small diameter, it’s a bit difficult to carry out this method.

Hard to obtain the diameter of the top of the inner ring gear in practice.

2.Direct measuring method

Method to implement

First choose a special auxiliary caliper pin that matches the inner ring of the deep groove ball raceway. Fixate it on the caliper pin of the 1.5m caliper. Use this specially-made caliper to measure the deep groove ball raceway. The measuring results minus the auxiliary caliper pin value would be the diameter of the deep groove ball raceway. The auxiliary caliper pin should be made semicircular in its front section and the rear part should be fixated on the caliper pin of the caliper by the cylindrical pin. When measuring, choose the auxiliary caliper pin according to the dimensions of the deep groove ball raceway.

Analysis of advantages and weakness of this method:

Advantages:

Ease of use of this measuring method, no special skills required. (2) Solve the difficult problem of measuring the small deep groove ball raceway, which is usually hard to measure . (3) No need to measure the diameters of the top of the inner ring gear. (4)Direct measuring method results in smaller measuring errors. (5) High time and work efficiency.

Weakness:

The measuring tools need to be self-made.