Gear train/transfer for medical device.

[Medmach]

We are working on a new power tool project which has drive transfer at 90° or 83° (decision on angle of drive transfer will be taken after feasibility study). At this moment we are working on various different options for this drive transfer from vertical motor to horizontal drive train.

Few of them are :

1. Using 90° bevel gear set from motor pinion to drive shaft gear.
2. Using 83° bevel gear set from motor pinion to drive shaft gear.
3. Using Face gear set for drive transfer at 90 or 83°.

Right now we are also working on gear ratio of 1.71:1 (custom), 1.5:1 (standard) or 1:1 for above configuration.

I have also attached tentative spec for bevel & face gear with this post. Have a look on it.

The tentative spec for vertical motor:

Motor Torque 1.6875 in-lbs

Motor RPM max 21000

The main questions which are rolling in my mind & would like to get input for are:

· The practicality of face gears vs. bevels for these uses.

· Feasibility (noise and strength considerations) for the high speed and low speed designs. (We have gear train also in our design and we are also doing feasibility of putting this gear train before / after drive transfer. If we put gear train after drive transfer than probably drive transfer gears will rotate at high pitch line velocity (approx 3200 ftm) and if we do drive transfer ahead of gear reduction by gear train than drive transfer gears would rotate at 250 ftm pitch line velocity.

· Cost consideration for gears at 90 and 83 degrees, and whether there is a difference both for face and bevel gears.

Any input will be very helpful...application is medical/surgical device hand pieces.

 

[MikeHalloran]

Face gears/ crown gears are generally crap.

For higher ratios, you could use Helicon or Spiracon gears, which are not crap, and priced accordingly.

You didn't tell us the output shaft speed, or the 'gearset' ratio. If you make the direction change and the speed reduction in one pass, you save an entire gearset, associated bearings, etc.



Mike Halloran
Pembroke Pines, FL, USA

 

[Medmach]

Here is an attachment to the specs being considered.
Thanks

 

[mfgenggear]

Mike

where did you come up with this one? I never heard of a helicon gear set.

http://www.youtube.com/watch?v=I7CGsY1eNms

why are face gears are generally crap?



Mfgenggear
if it can be built it can be calculated.
if it can be calculated it can be built.

 

[MikeHalloran]

Two Helicon gearsets were at the heart of a blood cell counter I worked on some decades ago. I couldn't find a picture, sorry.

Face gears are usually found in toys, and subject to budgetary constraints, or in outboard motor handles, where they are subject to geometric constraints.


Mike Halloran
Pembroke Pines, FL, USA

 

[MrRock109]

hi, I found some information you put in an earlier post regarding the mattson bevel gear attachment as used on a shaping machine, which I am interested in, as I have a book on this, which I have leant to a friend. I am interested in making my own one, but have little information regarding this.
Anyway, to attend to your question, here is an article which you may find of interest regarding right angle drives, see

http://www.zakgear.com/Hypoid_worm.html

which may be a cheap solution, with a very good answer.