Help on JIS D2001-1959/JIS B1603-1995 spline 1

[origbiscuit]

Hi - I am trying to design a hub with female splines to fit with a shaft, that has the following splines:

Axle Info
* Spline Std = JIS D2001-1959 (Japanese Automotive spec) (this spec has been superceded by JIS B1603-1995)
* 12x10x1 (12mm nom dia x 10 teeth x 1 module)
* Addendum modification coeff = 0.8
* Press angle 30 deg
* Flat root spline
* Unknown tol class for tooth width, I assume standard tol class for a sliding fit.


The hub will be a powdered metal part, since there is no power transmission between the shaft and the hub; the only requirement is that the hub can be fixed/held externally with a tool, so that a mating part can be unthreaded off of the end of the shaft. This results in minimal static torque reaction between the hub and the shaft.

I need to create a 3D model of the hub, so that the "mold" can be made for the powdered metal production tooling. Since there is no power tranmission, the teeth will not be cut, but formed net shape.

If possible can someone point me to a program that can create the spline data for importing into Unigraphics, or a program that can create a .dxf file. Or maybe someone can be kind enough to create the info for me and post it?

From what I have read, the JIS spec is similar, but not the same, to the DIN standard for involute splines.

Also I am considering designing the gear tooth profile without the involute shape, just a straight line, since there is no power being transmitted (if I can't get the involute profile data). Thoughts or comments on this?

BTW I do have the JIS specs (translated in English).

Thanks!

 

[gearcutter]

If you can get a copy of the specs to me I can send you an IGES, SAT, Iventor or Solid Works 3D model of the hub. If you prefer 2D I can also do a DXF.
Go to the link below where you'll be able to email me with your contact details. Don't post your email here or your post will be deleted from the forum. I'll then get back in touch with you so as you can send me a copy of the specs.

http://www.aussieweb.com.au/email.aspx?id=1194181

 

[gearcutter]

JIS D2001-1959 is for automotive splines with 20 deg P.A. & not 30 deg P.A. as you’ve noted in you post.
Do you have more information on the shaft such as measurement over pins or circular tooth thickness? In other words, what tolerance or type of fit will you require between the mating parts?
Do you have a sample shaft to work from?

 

[gearcutter]

The old "generated vs base pressure angle" problem again. I though I'd share the follow ups via email on this thread. Any thoughts as to how I might have worded my response would be appreciated.
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gearcutter:
The way you should look at pressure angles of splines is by the generating tool’s angle. If the tool is 20 degrees then the spline should be defined as 20 degrees. The generated pressure angle will be different depending on the amount of profile shift or addendum modification. The pressure angle also varies along the involute curve, starting at the base circle all the way to the tip of the tooth. However the pressure angle at the base circle can not change and in this case must always be 20 degrees, this is the important thing to remember as the base circle is what the involute curve is derived from. No amount of profile shift will change the pressure angle at the base circle. The only thing that can change the base pressure angle is the tool used.
Your tooling supplier should know this and I’m surprised that they are questioning the standard……a splines pressure angle is never defined by the generated pressure angle. You should tell your supplier that it is 20 degrees with the appropriate amount of addendum correction and “that’s it”. Don’t let them confuse you with different pressure angles found along the involute curve as this is irrelevant……remember that it’s the pressure angle at the base circle that is the only pressure angle anyone should be talking about.
How did you come up with the tool form to create the drawing you sent to the tooling supplier? A generating tool’s shape is going to be different to a non-generating tool’s shape such as a broach. If you are getting the hubs broached (which is practically the only way of manufacturing these small items other than Wire EDM) then you’ll have to design the broach’s shape and give this to the supplier.
I’ll put a DXF of the hub & shaft together for you in the next couple of days.

Cheers,
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origbiscuit:
I have another question about the involute spline standard I sent you. My understanding that per the JIS D2001 spec, the PA is 20 deg at the base of the tooth, and due to the nature of the involute shape, the angle at the pitch diameter is 30 deg, where the teeth theoretically meet. This applies to either female or male splines, correct?

The reason I ask is that I am also designing a 7mm (7z x 0.75m x 20) hub per this JIS D2001 standard. I sent the tooling drawing to the broach tool maker, he thinks the PA should be 30 deg, but I am assuming he is used to making ANSI spec broaches which probably have a 30 deg PA.

Also if you could, could you draw out a .dxf file of this hub (7 tooth x 0.75m x 20) in millimeters and send it to me? That would clear things up for them. I am designing the hub for a sliding fit, so per pg 310 of the JIS B1603 document I sent you, the tolerances are:

* Major diam: 7mm (-.013 / -.028) -- R7 tol
* Minor diam: 5.5mm (+.012 / 0) -- H7 tol
* Measurement over pins: 3.872 +.055 / 0 (1.5mm pin diameter)

Greatly appreciate the help!

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origbiscuit:
Regarding the PA, thank you for catching my mistake. I must have typed that wrong.

Regarding the shaft, I do not have any information on the circular tooth thickness. In this application, the type of fit can be sliding or clearance type fit. There is no power transmission between the shaft and hub. The hub's function is allow the shaft to be fixed, when removing a mating part off of the end of the shaft (threaded end). So per pg 301 of the spec, I would classify the fit as "loose" or at best "sliding".

My guess is that the shaft is made per the class a (loose fit). Inspection of a sample production axle here shows no chamfer on the tooth tip, so the shaft is probably designed for tooth flank fit. Also I measured a sample shaft, and the over pin (using two Ø1.8mm gauge pins) measurement was 13.415mm using a micrometer. So per the table on pg 313, the shaft falls into the class a or "loose" tolerance class.

So for the hub, per the table on pg 313, I am assuming the following tolerancing:

* Major diam: R7 tol (-.016 / -.034)
* Minor diam: H7 tol (+.015 / 0)
* Measurement over pins: 8.066 +.07 / 0

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gearcutter:
JIS D2001-1959 is for automotive splines with 20 deg P.A. & not 30 deg P.A. as you’ve noted in you post.
Do you have more information on the shaft such as measurement over pins or circular tooth thickness? In other words, what tolerance or type of fit will you require between the mating parts? Do you have a sample shaft?