Bearing help needed

[CHA5]

Help, I've never worked with bearings. All of my previous parts have been simple 2d/3d single items but this one is going to be very complex.

From the Solidworks image. I need to fit a roller bearing & a plain bearing into the blue highlighted lever. The lever can be anything from 6mm-10mm but I have no idea how to fit a bearing in there. Will I have to ream the hole then press or loktite in the bearing? Won't the nut & bolt lock it all up anyways?

The lever needs to be able to move freely, the black item is a hydraulic master cylinder which needs to be operated by a thumb activated lever.

[Manxmodder]

CHA5, I think you probably need to provide us with a bit more detail of the speed and loads the bearings are going to be encountering and is this just for providing a couple of pivot points in a lever mechanism or is there high speed high rpm involved.

Initially looking at your application there may be a simple solution by fitting plastic polymer bush bearings,such as the ones sold by igus bearings in their thin walled bush selection.
Link to igus below,have a browse to see if you can find similar applications on their site.....OZ.
http://www.igus.co.uk/iglidur

[CHA5]

It'll need to move in an arc of approx 30deg. It's just a thumb operated lever activating a brake MC, used infrequently with very little pressure applied.

It needs to be a roller bearing for 'feel' rather than an engineering reason.

[Jonny]

Design in and fit one of these for the pivot MR106ZZ which is 6mm bore x 10 o/d x 3mm thick.
Tension up to get the feel guaranteed to work.

Just drill through for the bore and counterbore with a 3 flute 2.8mm deep, easy.

[Manxmodder]

It'll need to move in an arc of approx 30deg. It's just a thumb operated lever activating a brake MC, used infrequently with very little pressure applied.

It needs to be a roller bearing for 'feel' rather than an engineering reason.

CHA5, I don't understand why you believe you will get better feel using a roller bearing than a plain low friction bush.

I use ball bearings,roller bearings and plastic polymer bearings quite frequently on projects and I don't see anything within your application that would persuade me to fit a roller bearing.

[BaronJ]

It'll need to move in an arc of approx 30deg. It's just a thumb operated lever activating a brake MC, used infrequently with very little pressure applied.

It needs to be a roller bearing for 'feel' rather than an engineering reason.

CHA5, I don't understand why you believe you will get better feel using a roller bearing than a plain low friction bush.

I use ball bearings,roller bearings and plastic polymer bearings quite frequently on projects and I don't see anything within your application that would persuade me to fit a roller bearing.

I agree with Manxmodder !  If its just pushing a master cylinder rod, I assume that you will also be fitting a return spring, or are you trying to rely on the back pressure returning the lever to its normal position.

[CHA5]

I assume that you will also be fitting a return spring, or are you trying to rely on the back pressure returning the lever to its normal position.

It doesn't need a separate return spring, there is a spring built into the MC. Hydraulic clutches & front brake MC's on motorcycles don't have separate return springs & they are only fitted to foot operated rear systems for construction & use regs'. The MC I'll be using is proven to not need any extra help on returning.

I've been to a bearing shop today & picked up an assortment of roller & plain bronze bearings. They don't stock plastics in such small sizes so I'll order an assortment off the net. I'm happy to experiment & the device will certainly gets lots of real world abuse during R&D.

This is the first time I've worked with bearings, I'm more interested in how to get the hole size right & how to keep it all working once it's all bolted up.

Any help appreciated.

[BaronJ]

Hi Cha5,


When I'm machining a bore for a bearing I aim for a push fit with my fingers not with a press.  The important thing is the finish on the bore.  The last few tenths are polished using emery cloth.  I usually go for a piece that is quite well used since its easy to introduce scratches with new stuff especially if its on the coarse side.


The other thing that I note from your drawing for maximum rigidity the spindle wants to be as short as convenient.  This will reduce the twisting moment on the bearing surfaces.