Gear Lab - Cylindrical, Bevel, Face Gears

antlu65

(Writing this partly to organize my own thoughts, and possibly to spur further discussion or comments.)

I think many of these issues result from my (admittedly poor) decision to include all types of gears in the feature. The bevel angle input was meant to allow users to create different types of gears, including cylindrical and face gears (bevel angle = 0 and 90, respectively). As someone who was completely new to gears, I thought this was a neat feature for exploration and learning. As has been mentioned in previous posts, this is far from the ideal workflow for generating a bevel gear pair. As currently implemented, a gear pair must be created sequentially, instead of simultaneously. The first gear's bevel angle and tooth count (δa, Za) are fixed after creation. When creating the second bevel gear, the user specifies a desired shaft angle (Σ, Zb) and the feature attempts to satisfy these constraints by calculating the second gear's bevel angle δb. The range of bevel angle δb is continuous, whilst the range of tooth count Zb is discrete - the latter is restricted to integer values. It is not always possible to satisfy the user-requested shaft angle Σ, given the user's other inputs. I readily concede that these details were not communicated properly, and even if they had been, would be a poor design choice for most users who want to create bevel gear pairs. Much frustration ensued, and I extend my apologies to the injured parties.

Instead, from what I have gathered from comments and other linked bevel gear features / calculators, a better workflow would be if the user could specify both tooth counts Za, Zb (and consequently the gear ratio) and shaft angle Σ. The feature would then calculate the bevel angles δa, δb to exactly satisfy the inputs.

antlu65

https://forum.onshape.com/discussion/comment/108664#Comment_108664

@james_aguilar160

"Importing the number of teeth I want and my desired shaft angle, and then picking any face width. Adjusting the face width didn't seem to affect things. Then, I took the bevel angle output from that calculator and input it into OnShape. Onshape is still reporting shaft angles about five thousandths of a degree off from perfectly level, but I think that the manufacturing processes I'm using are not up to producing this level of precision anyway, so this is good enough for me.

The ideal would be if the featurescript could be updated to automatically calculate the bevel angle."

Roger that. Unfortunately, my code was not structured for the workflow described. I think the best solution would be to create a new bevel gear feature - I will look into that.

Drew

First, I'd like to say that this is the easiest gear tool. I really like that you added the feature for internal gears, it saves having to use workarounds.

Now, I would just like to see if there's some clarity you can provide on how some of the fields get calculated. Tooth width and Internal gear ring depth seem to be a ratio of something. I can't seem to just input a number that gives me the width of the tooth and the outer ring diameter exactly. IE, I want a gear with a Module of 2.5, with 200 teeth, outer diameter of 555mm, and width of 25mm. To get these numbers tooth width is 10 and Ring Depth is 9.75. It seems width is just the Module x Tooth width. But I can't seem to make a good correlation with the Ring Depth.

Thanks.

alessio_zoboli

Hello, your function was very helpful to develop bevel gears for my parkinson's auto stabilizing spoon. I'm going to use them in my universitary project so I would like to ask your permission to use them for it. I would really like to thank you for you great work.