Driveshaft Splines
Discussion
Ive bought some drive shafts for my car. The shaft spline into the outer CV joint cage is fairly loose fitting.
A couple of people have said its not right for there to be play and Im not sure myself but wondered if anyone knew any better on here? Ive spoken to the guy who made them who says its normal (which it may be)???
A couple of people have said its not right for there to be play and Im not sure myself but wondered if anyone knew any better on here? Ive spoken to the guy who made them who says its normal (which it may be)???
Just to clarify, this is what I mean, the driveshaft spline to cage. Im holding the cage so it cant move so all that's moving is the splines.
https://vimeo.com/45724648
Just out of interest, if it is mean to be slightly loose, why is that? I would have thought engagement should be spot on. Ive taken apart Rover and Honda TypeR driveshafts and both are a tight fit.
Thanks
https://vimeo.com/45724648
Just out of interest, if it is mean to be slightly loose, why is that? I would have thought engagement should be spot on. Ive taken apart Rover and Honda TypeR driveshafts and both are a tight fit.
Thanks
Edited by boblet75 on Friday 13th July 23:01
Honestly to me there is sod all wrong with the parts shown ,a little play but come on production tolerances can vary enormously unless you are going to be putt vastly more than orig power through them lube wll fit and get on with it ! ,if you are really picky /pedantic buy borrow 1000 shafts or so and spend a month on selective assembly!!!!!
no way would i be fitting that to my car!
It should be a tight sliding fit. The geometry and "meshing" of the splines is critical to the load carrying performance of the joint. It absolutely must not incur a point load, or the pressure will result in immediate material failure.
A typical car, making 300nm (not including dynamic forces such as those when you "dump the clutch" etc which can be as large again as the static loads!) at the flywheel, in 1st gear (say 2.6:1) and with a final drive ratio of say 4:1 will be loading it's driven wheels with 3120Nm.
If we assume that is evenly shared by both wheels, and that the mean contact radius of the splines is 14mm (28mm dia) then there is 111.4kN of force in that joint. Shared across multiple splines thats ok, point loaded into a couple, er, no, that would be bad!
It should be a tight sliding fit. The geometry and "meshing" of the splines is critical to the load carrying performance of the joint. It absolutely must not incur a point load, or the pressure will result in immediate material failure.
A typical car, making 300nm (not including dynamic forces such as those when you "dump the clutch" etc which can be as large again as the static loads!) at the flywheel, in 1st gear (say 2.6:1) and with a final drive ratio of say 4:1 will be loading it's driven wheels with 3120Nm.
If we assume that is evenly shared by both wheels, and that the mean contact radius of the splines is 14mm (28mm dia) then there is 111.4kN of force in that joint. Shared across multiple splines thats ok, point loaded into a couple, er, no, that would be bad!
Fish981 - And this is the problem. Ive reassembled Ford focus shafts/CVs, compared these shafts with Honda Type-R and Rover spline fit. Ive never seen this before.
Mick - For a start, how do you know theyre not £1000 shafts?
Im not being picky, Im being careful. Lets say ive driving along and one lets go and I take another car out or somebody on the side of the road. These were not cheap shafts and when I have various people telling me theyre not right, should I ignore them? Would you? This could all go away so easily but I fear its only going to escalate.
Max_Torque - This is what ive read about spline engagement (Shigleys mech design) but I dont have the practical knowledge (hence asking around). These are for a car that will be used on track with more than 300nm!
Mick - For a start, how do you know theyre not £1000 shafts?
Im not being picky, Im being careful. Lets say ive driving along and one lets go and I take another car out or somebody on the side of the road. These were not cheap shafts and when I have various people telling me theyre not right, should I ignore them? Would you? This could all go away so easily but I fear its only going to escalate.Max_Torque - This is what ive read about spline engagement (Shigleys mech design) but I dont have the practical knowledge (hence asking around). These are for a car that will be used on track with more than 300nm!
My comments were my thoughts ,backed up by a life time in the trade and not a little experience in comp car prep and build , you will no doubt go your own way and thats your choice ,if you have issues with the quality of fit in the components take then back get a refund and start again . selective assembly may well find what you are looking for but will involve delay and prob cost good luck with the project and I hope you get a result and enjoy your car
I think we should be absolutely clear here:
That issue is NOT one of production tollerancing or selective fit. If you care to take a look at a set of drawings for a multispline joint, you will see tollerance in the order of 10's of microns, not in mm !!
I have a nagging idea at the back of my head that metric and imperial splines sized around about 1 inch do fit together but cause that sort of poor fit ??
to repeat: The joint should be a tight sliding fit, possibly needing a small amount of force (light hammer taps etc) to push the parts together. Any free play or slop will result in point loads, fretting and vibration noise. All of those WILL result in early life failure (whether that is the first time you "dump the clutch" or 10k miles down the line who knows, but it is not, imo, sensible to use those parts)
That issue is NOT one of production tollerancing or selective fit. If you care to take a look at a set of drawings for a multispline joint, you will see tollerance in the order of 10's of microns, not in mm !!
I have a nagging idea at the back of my head that metric and imperial splines sized around about 1 inch do fit together but cause that sort of poor fit ??
to repeat: The joint should be a tight sliding fit, possibly needing a small amount of force (light hammer taps etc) to push the parts together. Any free play or slop will result in point loads, fretting and vibration noise. All of those WILL result in early life failure (whether that is the first time you "dump the clutch" or 10k miles down the line who knows, but it is not, imo, sensible to use those parts)
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