Planetary Gear Inner Gear

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NormandC
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Re: Planetary Gear Inner Gear

Postby NormandC » Sun Sep 30, 2018 6:37 pm

OakLD wrote:
Sun Sep 30, 2018 5:25 pm
Thank you, this tool has option for external and internal teeth. However, the "High precision" option doesn't do anything aparent to
Maybe it's just your 3D view display tessellation settings. Default is 0.5% which will approximate curves with straight line segments.
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OakLD
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Location: Brno

Re: Planetary Gear Inner Gear

Postby OakLD » Mon Oct 01, 2018 9:27 pm

NormandC wrote:
Sun Sep 30, 2018 6:37 pm
Maybe it's just your 3D view display tessellation settings. Default is 0.5% which will approximate curves with straight line segments.
Thank you for your suggestion. Do you mean Edit --> Preferences : Part Design Section : Shape View Tab : "Maximum deviation depending on the bounding box" with default value 0.5%? What is a "correct" value to get proper shape? I tried also 0,05% and 0,5% including FreeCAD restart and see no progress.

Since I'm on RealThunder's line of FC builds (0.8.3), I also tried "factory" FC16, which I also have on my machine. Both give me exactly same bad result :(.

EDIT: I think it's not the display issue only. It came to my mind, that I can export the shape to DXF; I then opened the DXF in DraftSight and I can see the tooth sides are really formed by 3 lines each.
DraftSight_gear.PNG
DraftSight_gear.PNG (7.81 KiB) Viewed 348 times
Perhaps I do something wrong or have a wrong setting, but I don't know where to look to fix it...

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.14369 (Git)
Build type: Release
Branch: (HEAD detached at FETCH_HEAD)
Hash: 45b39e8ff6861d15f4277f9759d012b41aae071f
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: Czech/CzechRepublic (cs_CZ)
Regards,

Oak
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Kunda1
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Re: Planetary Gear Inner Gear

Postby Kunda1 » Mon Oct 01, 2018 9:36 pm

OakLD wrote:
Mon Oct 01, 2018 9:27 pm
Since I'm on RealThunder's line of FC builds (0.8.3), I also tried "factory" FC16, which I also have on my machine. Both give me exactly same bad result :(.
realthunder's fork is very different than the main FreeCAD repo. Can you recreate the issues you are reporting on 0.17 and 0.18dev?
FYI, realthunder's fork is currently on 0.8.6
Want to contribute back to FC? Checkout:
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OakLD
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Re: Planetary Gear Inner Gear

Postby OakLD » Mon Oct 01, 2018 10:21 pm

Kunda1 wrote:
Mon Oct 01, 2018 9:36 pm
realthunder's fork is very different than the main FreeCAD repo. Can you recreate the issues you are reporting on 0.17 and 0.18dev?
FYI, realthunder's fork is currently on 0.8.6
Sure I'll try. I have 0.17 on my W7 machine, I'll test it there on Wednesday. I'll try to install 0.17 on this W10 machine and test it (not tonight). I perhpas could test it on my OpenSuSE Leap 0.43 machine, depending on that I could get functional SUSE executables of 0.17 release or build it without issues.

Ooops, I've got the latest (0.8.6), just messed up the numbering... Sorry.
Regards,

Oak
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meme2704
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Re: Planetary Gear Inner Gear

Postby meme2704 » Tue Oct 02, 2018 8:47 am

Oooops :mrgreen:
I see that I have an approximation:
Fc in his great wisdom has provided gears with internal teeth, and clicking "external = false, we have the internal teeth
Attachments
external pinion.FCStd
(967.41 KiB) Downloaded 11 times
external pinion.PNG
external pinion.PNG (61.38 KiB) Viewed 321 times
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OakLD
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Re: Planetary Gear Inner Gear

Postby OakLD » Tue Oct 02, 2018 11:20 am

OK, everywhere same result. W7 tested over remote desktop, but that shouldn't matter...


OS: Windows 7
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.13522 (Git)
Build type: Release
Branch: releases/FreeCAD-0-17
Hash: 3bb5ff4e70c0c526f2d9dd69b1004155b2f527f2
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: Czech/CzechRepublic (cs_CZ)

OS: Windows 7
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.6712 (Git)
Build type: Release
Branch: releases/FreeCAD-0-16
Hash: da2d364457257a7a8c6fb2137cea12c45becd71a
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17

OS: Windows 7
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.14369 (Git)
Build type: Release
Branch: (HEAD detached at FETCH_HEAD)
Hash: 45b39e8ff6861d15f4277f9759d012b41aae071f
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: Czech/CzechRepublic (cs_CZ)

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.6712 (Git)
Build type: Release
Branch: releases/FreeCAD-0-16
Hash: da2d364457257a7a8c6fb2137cea12c45becd71a
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.13541 (Git)
Build type: Release
Branch: releases/FreeCAD-0-17
Hash: 9948ee4f1570df9216862a79705afb367b2c6ffb
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: Czech/CzechRepublic (cs_CZ)

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.14369 (Git)
Build type: Release
Branch: (HEAD detached at FETCH_HEAD)
Hash: 45b39e8ff6861d15f4277f9759d012b41aae071f
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: Czech/CzechRepublic (cs_CZ)

OS: "openSUSE Leap 42.2"
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.Unknown
Build type: Release
Python version: 2.7.12
Qt version: 4.8.6
Coin version: 3.1.3
OCC version: 6.9.1.oce-0.18


So there's something with my FC settings or system configuration or something wrong between keyboard and the chair :-).
Regards,

Oak
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NormandC
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Location: Québec, Canada

Re: Planetary Gear Inner Gear

Postby NormandC » Wed Oct 03, 2018 4:52 am

Can you please share your file?
ian.rees
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Re: Planetary Gear Inner Gear

Postby ian.rees » Wed Oct 03, 2018 6:10 am

meme2704 wrote:
Sun Sep 30, 2018 1:26 pm
know this is an old thread.

But I want to emphasize, that if you substract involute gear from a cylinder you DON'T get valid involute inner teeth.
I did it yesterday, but it was too quick thinkging. The result could be acceptable for some info graphics, but certainly not e.g. for 3D printing a real gear.

I think, that at this moment, the only way is to take an engineering handbook and draw a precise sketch to base the gear with inner teeth on...
Complete Fake news, you do not know anything about machining pinion, look at my answer 2 post above :!: :!: :mrgreen:
Let's try to keep a more respectful tone, please.

Also not a gear expert, but I think the internal/external spur gear difference is a little more than just terminology (and, I am sure that "external" in this context means "spur that has the teeth pointing out" - the Part Design tool is the right way around). The addendum of one becomes the dedendum of the other, obviously, and the involute parameters will be the same. But, I think as a practical matter you'd not want to specify the root radius of the internal gear, by making a rounded tooth tip of an internal gear, then inverting it... Often the internal gear has to have different dimensions to prevent the tips of teeth from interfering, and that sort of thing too.

That said, looo has made a rather nice gear workbench: https://github.com/looooo/FCGear

As to the "bug" - mine looks fine when I ensure that the visualisation deviation is low enough:

OS: Ubuntu 18.04.1 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.14803 (Git)
Build type: Debug
Branch: master
Hash: ff0cacca0ad016948f42377333644ccecb875936
Python version: 3.6.6
Qt version: 5.9.5
Coin version: 4.0.0a
OCC version: 6.9.1.oce-0.18
Locale: English/UnitedKingdom (en_GB)
UR_
Posts: 935
Joined: Tue Jan 03, 2017 8:42 pm

Re: Planetary Gear Inner Gear

Postby UR_ » Wed Oct 03, 2018 11:40 am

OakLD wrote:
Mon Oct 01, 2018 9:27 pm
It came to my mind, that I can export the shape to DXF; I then opened the DXF in DraftSight and I can see the tooth sides are really formed by 3 lines each.
Exporting to DXF is not a got choice to evaluate curves data.
Please see here: https://forum.freecadweb.org/viewtopic.php?f=3&t=31280

Better will be using Info tool from CurvesWB.

2018-10-03 13_27_08-FreeCAD 0.18.png
2018-10-03 13_27_08-FreeCAD 0.18.png (41.63 KiB) Viewed 250 times
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OakLD
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Location: Brno

Re: Planetary Gear Inner Gear

Postby OakLD » Fri Oct 05, 2018 7:47 am

UR_ wrote:
Wed Oct 03, 2018 11:40 am
Exporting to DXF is not a got choice to evaluate curves data.
Please see here: https://forum.freecadweb.org/viewtopic.php?f=3&t=31280

Better will be using Info tool from CurvesWB.
I'm going to learn something new :-).

But if it is a screen and DXF processing issue, I still may need to export correct object in DXF or STEP later. And as for now, the DXF is wrong too and I have no idea what is causing the issue.
Regards,

Oak