Kaydon - KAA17BG0Z_B2B - Angular contact bearing, duplex pair B2B

[divyashah]

Description	Field
Datasheet component	[link or attachment ]
Project	ergoCub (& future) joints
Alias Creo	KAYDON_KAA17BG0Z_B2B
IIT-Code	16073
Applicant	Divya Shah, @divyashah
Supervisor	Andrea Mura, @MrAndrea
Maintainer	Marcello Savoldi, @marcellosavoldi
Coworkers	@icub-tech-iit/silo-mech

Attachment:

Notes:

Checklist:

Complete the checklist in order to proceed with the request.

• [x] Created the Alias following the standard convention.
• [x] Added, if necessary, the source files (STEP, IGS, etc), the links/datasheets/drawings or other information used to create the library part.
• [x] File imported using the Creo start part commercial.
• [x] Checked mass properties.
• [x] Checked if one special case applies to this component.
• [x] Converted the files with the EDU-COM license.
• [x] Created IIT code in WINGST with manufacturer and at least one supplier.

[divyashah]

Added the file with the previous commit.

As per the data sheet the weight of the single bearing should be 0.045 pounds which is about 0.02041 kg. So for a duplex pair, the weight is about 0.04082 kg. CAD is aligned with the datasheet.

[divyashah]

Some useful information from the supplier regarding the use of this duplex pair of angular contact bearing:

For preloaded bearings, we do not recommend interference fits for factory preloaded bearings. Interference fits will effectively increase the preload in the bearing.

We also recommend that the shaft and housing diameter tolerances be the same as the bearing tolerances.

At a maximum preload of 0.018 inch, we expect .0001 inch (0.0025 mm) of outer ring stretch and .0001 inch (0.0025 mm) of inner ring compression after preload. (See attached printout).

Therefore, we would suggest a shaft tolerance of 44.4325 +0/-0.015. The recommended housing ID would be 53.9775 +0.013/-0

If the shaft and housing coefficients of thermal expansion (CTE) are different than the bearing, then the fits may need to be adjusted if the bearing needs to operate at high or low temperatures, to compensate for the differential thermal expansion.

The bearing set has an overall width tolerance of +0/-0.25 mm. Therefore the “A” and “B” gaps shown below should be at least 0.25mm, and no more than 0.50mm.

As we have discussed before, we generally try to keep the clamping stress below 6000 psi. For this size part, the maximum clamping force should not exceed 7000 N on the inner ring or 8100 N on the outer.

To prevent excessive clamping they may want to consider using shims in the “A” and “B” gaps.
That would be considered best practice, but is rarely done.

cc @marcellosavoldi

[divyashah]

The real weight measured for two single bearings is 0.0392 kg. Since the difference with respect to the datasheet weight for a duplex pair is not much (<4%), we can leave the mass properties as it is.

I think then we can close this issue.