Thread: Radial Force on Ball Bearing Via Vice Setup, Type of Vice Recommendation Needed

Originally Posted by dian

can you draw a picture of what you are doing? shaft parallel to jaws and vice somehow assmetrically squeezing the bearings? dont you want to have some controll over the force? fine adjustment, measurement? a vice is not suitable for this.

i would use a leveraged fish scale for this purpose.

This is a rough sketch of what I have in mind, any obvious issues with this design?

This is a rough model of my idea. The two bearings being tested are in RED. Any obvious issues with this idea? the arbor press idea is popular, but it would put a big toll on the motor if im not mistaken. The setup I have is to prevent the shaft from experiencing the heavy load and transferring that load to the motor and other components.

This is cheating A bearing always will be in a housing riggid enough to keep the outerrace round In this setup you will deform the outerrace and that will result in different wear as in a real world situation
I would make some sort of housing A hole to size in a piece of thick sheetmetall will dPeter

Simplest setup is with a aircilinder The setup will not consume air beside some mi or leaking perhaps With a regulator you can adjust the force very easy And it can be acompact setup Weld a U shapefixture that holds the cillinder and the bearings
Peter

that was helpful Im not very familiar with air cylinder output, will it be enough to induce fatigue. The dynamic load of most of the bearings of interest is close to a ton (1500-2000 lbf).

BTW Whydo you have those2 pillowblocks over there?You already have 2 bearings in the motor/gearbox Now you have 4 bearings in line That needs a lott of alignment Bad situation in my book
Peter

I placed those there because I did not want to run the shaft from the motor directly. Instead what you see at the right of the picture is a belt driven pulley.

Why not directly A extension piece on the shaft perhaps if the shaft is not the right size
If you keep your setup with the 2 testbearings pushed either side you have very little load on the bearings of the motor
You still need only one air cilinder if you make it possible for the fixture to slide a bit so it is selfaligning
Simple Keep it simple

Why not put your test bearing between the pillow blocks? That makes it easy to put a half housing on the test bearing (not a vee block, although a vee block will will accellerate the failure)that you can use an air cyl with regulator or screw jack or arbor press with load cell to apply and measure the load . The pillow blocks should be sized for multiple the load of the test bearing using larger bores with shaft bushings if necessary.

That will be similar to actual use of the bearing without axial load if that is what you want.

Vee not a good idea for what should be obvious reasons.
Standard vise screw not such a good idea either unless you plan to use load cells to know the actual force.
Not sure what you are after here. Why?
Bob

One issue with the setup drawn is that the vise will need to 'float' in the same direction as jaw movement while being confined the other way. If not, the tiniest offset from either jaw referenced to the support bearings will cause uneven loading to the extent that the shaft is unable to bend. What I'm trying to say is that the load on the bearings will be uneven since some is almost certainly going to be taken in one direction by the pillow block set. Probably doesn't matter in this case though, unless you want to objectively compare the two bearings' failure.

3 bearings in the vise, one loaded between the other two, and belt drive the shaft. No need for additiknal pillowblocks to compensate for the moment or bending force produced by 2 bearings in the vise.

Vises are often fairly springy, a spring on an arm hanging off the vise leadscrew would keep force on the bearing.


For axial loading, you can fit bellville washers between the inner or outer race and simply bolt the stack together, and drive the outer race with a belt.

Seems to me that you'll need to properly press fit the bearings as they would normally be mounted to get meaningful results. If you are doing that, you can easily make a housing with one bearing and a smaller shuttle housing off of a flange from the first that is preloaded with belleville washers.

If you need RPM but don't need to transfer any load, I would just make the shaft aluminum with a flange and spin a magnet in close proximity to it.

so make rigid rectangular housings for three bearings and load the middle one. or just make one housing for the bearing to be tested and use two bigger bearings (like your pillow blocks) that will not mind the load.

This thread is a fool's mission and as described can not offer any useful education barring the misapplication of anti-friction bearings.

I suggest the OP reconsider the value of his efforts and intentions.