Epicyclic gear train

Post unfinished work here for feedback and advise.
DaveG27
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Epicyclic gear train

Postby DaveG27 » Wed May 20, 2009 2:32 pm

HI
Been working on and off on this epicyclic gear train for the past four weeks.
Just about to start rendering the carrier but looking at it overall something does not look quite right not being very artistic myself I wonder if someone can tell me what is wrong?
Fairly new to Inkscape and learned a lot about the program and it's quirks if I was starting over again I would take a slightly different approach.
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EarlyBlake
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Re: Epicyclic gear train

Postby EarlyBlake » Wed May 20, 2009 3:06 pm

Nice. Good job on the shading. How much time did that take?

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brynn
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Re: Epicyclic gear train

Postby brynn » Thu May 21, 2009 10:01 am

I'm not clear on how the highlights are working. On the top of the silver, there's the white highlight, and on top of the gold, a yellow highlight. They all seem to be smaller towards the center of each, and grow wider towards the outer areas. Why is that? I might expect that if light were emanating from the center points (somehow).

The other thing that seems "off", is the 3-prong white piece that sits on top of everything. It doesn't have the same detailed quality of the rest -- maybe it's just not finished yet?

All that said, it could be that I just have never seen such a device before. I do like the sharp, crisp quality of your style. And I like how everything is perfectly proportioned. Perfectly!

DaveG27
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Re: Epicyclic gear train

Postby DaveG27 » Thu May 21, 2009 11:23 am

The shading took ages to sort the technique out but once I got into the routine I could get along pretty quickly and I think if I did it again I could do it in a few hours? I have been thinking today there is a simpler solution I could have used which would have been quicker overall but slower at the early stage!
They all seem to be smaller towards the center of each, and grow wider towards the outer areas

If you look at a CD that is how the light reflect and you get the same effect on machined components.
Yes the three pronged thingy is not finished.
I think the perspective is not quite correct I had a lot of trouble getting the perspective tool to behave and I think I ended up doing it slightly wrong.
Below is a test I carried out before I started. The gear on the left the shading on the teeth is more consistent with how the light emanates. I had not done that in this case as it seemed O.K. at the time but I was viewing with stroke's on when I removed them the problem appeared. I will have to go back and sort the highlights out so it the same as my test!
My problem is I am an engineer by profession and are to precise and don't know when to use artistic licence?

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brynn
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Re: Epicyclic gear train

Postby brynn » Fri May 22, 2009 5:38 am

I think the perspective is not quite correct I had a lot of trouble getting the perspective tool to behave and I think I ended up doing it slightly wrong.

Yeah, the perspective tool gives me such fits that I pretend it's not there! But I don't notice any problems with the perspective on either image.

I think on the highlights, something of a cross between that in the 1st image and that in the 2nd, might work. LIke in the 1st image, if the highlights were blurred sort of like in the 2nd, yet still with the wedge kind of shape.. But not having anything in front of me to compare, and not having any experience with machined parts, I'm probably not the best judge :roll:

Simarilius
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Re: Epicyclic gear train

Postby Simarilius » Sun May 31, 2009 4:08 am

Nice image. The carrier doesnt look like its centered on the sun tho, as the hole and the rings on the gear arent concentric.

jeremiah
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Re: Epicyclic gear train

Postby jeremiah » Wed Jul 01, 2009 5:43 am

hi
im really impressed with work.
how do you calculate the centres of the sun gears ?

DaveG27
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Re: Epicyclic gear train

Postby DaveG27 » Sat Jul 04, 2009 8:48 pm

how do you calculate the centres of the sun gears ?

Basically I didn't it was more by trial and error. I found examples on the internet and found 12 teeth sun,12 planets & 36 outer ring. I then used the "render gear" in inkscape to create a 2D drawing and found they fitted perfectly. I then used the perspective function to create perspective view this the most difficult part as each gear had to be done separately with a lot of manipulation. I then used the extrude tool and ungroup each gear. This left a 3D look but a lot of things were in the wrong Z order which took of sorting out.
I also found 12 sun 18 planets 48 ring works so I think the formula for it is Ring=sun+2*planets but I could be wrong! but the gears should be nice multiples of each other i.e. 2,3,4 or 6 etc'
There are formula's for calculating the effective diameter of a gears which are best avoided.
I am working in a new version as there is a lot of things about the other I do not like.
Work in progress would like to add splined dive shafts but are still trying to think of a way to do it!
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DaveG27
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Re: Epicyclic gear train

Postby DaveG27 » Tue Jul 07, 2009 5:47 am

This is the completed version.
Click on image for larger version!
Image

jeremiah
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Re: Epicyclic gear train

Postby jeremiah » Wed Jul 08, 2009 7:14 am

thanks for the explanation ,im trying to draw planetary gear in autocad ring 60 teeth sun 30 and planets 15 teeth ,6 planets ,i have drawn all in 2d just trying to render

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ErikTiePie
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Re: Epicyclic gear train

Postby ErikTiePie » Wed Jul 08, 2009 7:36 am

It looks great, at fist view.

But, from a technical point of view, I don't think it would turn too smooth....

The teeth on the planet wheels and the outer ring are so closely matched, I think it would give a lot of friction. There's not enough room for the teeth from one side to slide between the teeth of the other side.

I think that can be solved by giving the outer ring similar teeth as the sun wheel.

DaveG27
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Re: Epicyclic gear train

Postby DaveG27 » Wed Jul 08, 2009 8:02 am

But, from a technical point of view, I don't think it would turn too smooth....

I think your right. The profile I think is entirely wrong for the ring, I took a normal gear generated by the render gear function in inkskape and differenced it with a circle. To lazy to find out or even to generate the correct profile.
edit I think the pressure angle is wrong on the ring.

DaveG27
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Re: Epicyclic gear train

Postby DaveG27 » Thu Jul 09, 2009 1:12 am

Update
Been doing some investigation into internal teeth profiles out of curiousity much to my suprise it seems its as I had done it, the reverse to an external gear!
7.2 Tooth Parts of Internal Gear
Because the internal gear is reversed relative to the external gear, the tooth parts are also reversed relative to the ordinary
(external) gear. This is shown in Figure 1.34. Tooth proportions and standards are the same as for external gears except that the
addendum of the gear is reduced to avoid trimming of the teeth in the fabrication process.

Link to PDF document

Thenomolitan
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Re: Epicyclic gear train

Postby Thenomolitan » Wed Sep 23, 2009 4:24 am

this kind of things i prefer doing with blender, you can choose a cartoon shader to get this effects.

crafter2u
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Re: Epicyclic gear train

Postby crafter2u » Mon Dec 14, 2015 4:28 pm

how did you make that planetary gear in inkcape?

crafter2u
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Re: Epicyclic gear train

Postby crafter2u » Mon Dec 21, 2015 7:45 am

i still dont know how to make this in inkscape

Lazur
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Re: Epicyclic gear train

Postby Lazur » Mon Dec 21, 2015 8:37 am

A (belated) welcome aboard!

Well you revived a quite old topic, doubt the original poster is reading this.

There is an extension to render gears and also an lpe to generate gears,
then you can use either the motion or extrude extensions to get a base.

Personally I don't think those gears are looking good, the real thing is based on involutes of a circle, which could be generated/constructed with an accurate shape.


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