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Gears in Comsol
Posted Apr 25, 2017, 5:50 a.m. EDT 3 Replies
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Hi everyone,
I am using the library part "spur gear 2D" to calculate contact pressure between two gears in contact. I have the dimensions of the gears set but when i try to plug the values in into Comsol i get an error message that says that the "Addendum of the gear is too large". The only way that i can get it to work is by adding a larger number of teeth to the gear (or by decreasing the addendum). Have anyone of you encountered this problem when working with this library part?
I have (or at least i hope so) calculated everything according to standard.
My input parameters is attached below.
The module of the gear is 4,5.
Help would be greatly appreciated.
Regards,
Anders Holmberg
I am using the library part "spur gear 2D" to calculate contact pressure between two gears in contact. I have the dimensions of the gears set but when i try to plug the values in into Comsol i get an error message that says that the "Addendum of the gear is too large". The only way that i can get it to work is by adding a larger number of teeth to the gear (or by decreasing the addendum). Have anyone of you encountered this problem when working with this library part?
I have (or at least i hope so) calculated everything according to standard.
My input parameters is attached below.
The module of the gear is 4,5.
Help would be greatly appreciated.
Regards,
Anders Holmberg
3 Replies Last Post May 30, 2017, 4:53 a.m. EDT
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Posted:
8 years ago
Dear Anders,
This type of error message is thrown when it is not possible to build a gear tooth geometry based on the given input parameters.
If you think that all the input parameters you have provided are correct and still library part fails to build the gear geometry, then kindly share all the input parameters you are using. So that we can investigate and if required suggest a work around for it.
Best Regards,
Pawan Soami
This type of error message is thrown when it is not possible to build a gear tooth geometry based on the given input parameters.
If you think that all the input parameters you have provided are correct and still library part fails to build the gear geometry, then kindly share all the input parameters you are using. So that we can investigate and if required suggest a work around for it.
Best Regards,
Pawan Soami
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Posted:
8 years ago
Hi and sorry for my late reply.
My parameters are:
Top diameter: 82,46 mm
Base diameter (or pitch diameter): 67,6579
Root diameter: 61,34
Normal module: 4,5
Number of teeth: 16
Pressure angle: 20°
This then gives:
Addendum = (82,46-67,6579)/2 = 5,23 mm
Addendum to module ratio = 5,23/4,5 = 1,231 mm
Tooth height = (82,46-61,34)/2 = 9,06 mm
Tooth height to addendum ration = 9,06/4,5 mm
Let me know if there is something missing!
Regards,
Anders Holmberg
My parameters are:
Top diameter: 82,46 mm
Base diameter (or pitch diameter): 67,6579
Root diameter: 61,34
Normal module: 4,5
Number of teeth: 16
Pressure angle: 20°
This then gives:
Addendum = (82,46-67,6579)/2 = 5,23 mm
Addendum to module ratio = 5,23/4,5 = 1,231 mm
Tooth height = (82,46-61,34)/2 = 9,06 mm
Tooth height to addendum ration = 9,06/4,5 mm
Let me know if there is something missing!
Regards,
Anders Holmberg
Please login with a confirmed email address before reporting spam
Posted:
8 years ago
Dear Anders,
Thanks for providing the gear parameters.
We have investigated this issue at our end. It seems like there is a restriction/check to limit the amount of addendum based on the working depth decided by the difference in the pitch and base diameter. Looks like for various reasons, we may want to have addendum value larger than this limiting value.
So now we have removed this restriction on the addendum. If you are using v5.3, you can update your Part Libraries in order to get the updated parts by following the below steps:
* Select Part Libraries from the Windows menu in the Home tab
* Click on the Update COMSOL Part Libraries
Regarding the gear parameters, I just noticed some of the minor mistakes. Please find below the corrected definitions and values:
Base diameter = 67.6579 mm
Pitch diameter = 67.6579/cos(20[deg]) = 72 mm
Addendum = (82.46-72)/2 = 5.23 mm
Addendum to module ratio = 5.23/4.5 = 1.162
Tooth height = (82.46-61.34)/2 = 10.56 mm
Tooth height to addendum ratio = 10.56/5.23 = 2.019
Let me know if you are still facing any issues while building the gear geometry.
Best Regards,
Pawan Soami
Thanks for providing the gear parameters.
We have investigated this issue at our end. It seems like there is a restriction/check to limit the amount of addendum based on the working depth decided by the difference in the pitch and base diameter. Looks like for various reasons, we may want to have addendum value larger than this limiting value.
So now we have removed this restriction on the addendum. If you are using v5.3, you can update your Part Libraries in order to get the updated parts by following the below steps:
* Select Part Libraries from the Windows menu in the Home tab
* Click on the Update COMSOL Part Libraries
Regarding the gear parameters, I just noticed some of the minor mistakes. Please find below the corrected definitions and values:
Base diameter = 67.6579 mm
Pitch diameter = 67.6579/cos(20[deg]) = 72 mm
Addendum = (82.46-72)/2 = 5.23 mm
Addendum to module ratio = 5.23/4.5 = 1.162
Tooth height = (82.46-61.34)/2 = 10.56 mm
Tooth height to addendum ratio = 10.56/5.23 = 2.019
Let me know if you are still facing any issues while building the gear geometry.
Best Regards,
Pawan Soami