Sonic Shifter - recent feedback?

[Paul Copioli]

BoilerMentor,

Were you guys using the old ball shifter shaft without the pin in it or the new shaft?

I ask because the press fit in the original shaft would allow the deflection you speak of but the new shaft would most definitely not.

Also, a cantilevered shaft with the proper bearing spacing behind it is a perfectly legitimate design strategy especially with the cantilevered gear so close to the external bearing face.

Additionally, this is the first example of a failure like this that we have seen with the 3 CIM shifter so I really would like to get more information from you.

PM me if you would like me to email you.

Again, this failure mode is not normal in the typical 3 CIM ball shifter use case (even with your ratios you are within our normal use case).

Thanks,
Paul

[aldaeron]

Originally Posted by Paul Copioli

BoilerMentor,
Also, a cantilevered shaft with the proper bearing spacing behind it is a perfectly legitimate design strategy especially with the cantilevered gear so close to the external bearing face.

It is a legitimate approach, but will have more deflection than if the end of the shaft were supported. Is the difference in deflection sufficient to cause a problem? Sounds like it was in a few cases.

Based on your reply (and the comparison here) it sounds like there were a lot of design changes in the v2 Ball Shifter Shaft. Under what circumstances do you recommend teams replace this shaft? We just bought the upgrade, but have not installed it.

[Paul Copioli]

Originally Posted by aldaeron

It is a legitimate approach, but will have more deflection than if the end of the shaft were supported. Is the difference in deflection sufficient to cause a problem? Sounds like it was in a few cases.

Based on your reply (and the comparison here) it sounds like there were a lot of design changes in the v2 Ball Shifter Shaft. Under what circumstances do you recommend teams replace this shaft? We just bought the upgrade, but have not installed it.

I would use the upgrade. The upgraded shafts are much better and allow for the use of the ThunderHex bearing without any additional machining.

By my math, the deflection difference is not enough to cause their problem. I believe it was related to a loose fit between the hex and shifter shaft in the v1 version of the ball shifter shaft combined with their increased load case.

[waialua359]

Originally Posted by Paul Copioli

I would use the upgrade. The upgraded shafts are much better and allow for the use of the ThunderHex bearing without any additional machining.

By my math, the deflection difference is not enough to cause their problem. I believe it was related to a loose fit between the hex and shifter shaft in the v1 version of the ball shifter shaft combined with their increased load case.

I bought several v1 Ball Shifters Transmissions when they first came out which are still unopened. We have yet to use them in our drivetrains, and used some of them instead for other robot features such as our winch for the ball launcher in 2014.
I better have them checked to possibly get the upgraded shafts.

[cbale2000]

Originally Posted by Paul Copioli

BoilerMentor,

Were you guys using the old ball shifter shaft without the pin in it or the new shaft?

I ask because the press fit in the original shaft would allow the deflection you speak of but the new shaft would most definitely not.

Also, a cantilevered shaft with the proper bearing spacing behind it is a perfectly legitimate design strategy especially with the cantilevered gear so close to the external bearing face.

Additionally, this is the first example of a failure like this that we have seen with the 3 CIM shifter so I really would like to get more information from you.

PM me if you would like me to email you.

Again, this failure mode is not normal in the typical 3 CIM ball shifter use case (even with your ratios you are within our normal use case).

Thanks,
Paul

I was wondering if someone from Vex would drop by this thread. Glad to hear this issue is an unusual/unique failure mode. Makes me feel better about our teams continued use of Ball Shifter Gearboxes (which as I've said already, we've been very happy with so far).