| Author |
Message |
Timothy J. Dressel (Tjd)
Junior Member
Username: Tjd
Post Number: 52
Registered: 4-2001
| | Posted on Friday, July 05, 2002 - 12:37 pm: | |
From my conversations with bearing guys, the reason for the /C4 spec, in addition to the high temperature mentioned, is likely the high speed requirements and very tight press fit on the shaft. --tim d |
Steve Magnusson (91tr)
Member
Username: 91tr
Post Number: 818
Registered: 1-2001
| | Posted on Tuesday, July 02, 2002 - 3:52 pm: | |
Rob -- the devil is in the alpha-numeric soup that follows the manufacturer's main ball-bearing part number (which always makes substitution difficult). Rather than "looser tolerances", I think it's more accurate to say that C4s have a "larger nominal radial internal clearance" than C3s (although other characters in the soup can be used to also control tolerance ranges). In addition to providing enough clearance for the operating conditions (thermal, fits, etc.), increasing the nominal radial internal clearance also increases the contact angle (when axially loaded) so the bearing can better support axial thrust loads. For the inner bearing (which I think takes the entire thrust load due to the helical spur gears) it would be best to stay with C4 rather than C3 if you can without undue hassle IMO. I've got a fairly comprehensive SKF catalog so let me know if you'd like to try to decode any other "supplementary designations". |
Robert W. Garven Jr. (Robertgarven)
Junior Member
Username: Robertgarven
Post Number: 57
Registered: 2-2002
| | Posted on Tuesday, July 02, 2002 - 11:47 am: | |
Dear Friends,
I tried to out source bearings from a local bearing house for my on-going project and was surprised by the suffix number of C3 on the bearings I got from them, which differed from the C4 suffix of the official Ferrari supplied
bearings. I learned from SKF that C4's would have looser tolerances in-between the balls and
races. They thought that Ferrari had specified the C4's for some reason which could include
internal expansion due to heat, etc. I ordered some bearings also from GT car parts and they sent
me the same C3's, which I returned. I have decided to go for the C4's thinking Ferrari engineers have some reason for using this application. Do any of you have any thoughts or information on this issue. Ric I know you know quite a bit about bearings?
Rob
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