Por d i f f e r e n t f i e l d s of application involving f i n e mechanics, see D I N Sheet 1 Section 4, Table I column 1 s p e c i f i e s a range. DIN Spur Gear Drives for Fine Mechanics; Tables. DIN Spur Gear Drives for Fine Mechanics; Indication in Drawings, Examples for Calculation.
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For the end faces of a gear blank which are used as contact face o r clamping face the permissible axial eccentricity Tea is specified in Table 5.
The e r r o r i n a x i a l parallelism i e designated by Spa. The uncertainty i n measurement due t o var i at i on of the measuring Observance of t h e s p e c i fi e d allowances may be determined d i r e c te.
Gear f i t s not l i s t e d i n this Table should be dih only i n exceptional circumstances. I n t h e equations gear 2 is t h e master gear.
Assuming t h a t t h e gear t o be t e s t e d i s within the scope according t o D I N Sheet 1, Sect i o n 2, the centre distance of s t r a i g h t or h ein l i c a l spur gears without addendum modification i s set on the dual flank r o l l t e s t e r a s folows: In this case the permissible radial eccentricity for the tip circle should be taken from Table 3.
When gears f o r which the gear blanks are disc-shaped are to be cut in batches, then, instead of a pemissible axial eccentricity for the face farthest from the contact face, a permissible degree of non-parallelism should be specified see Figure?
G e a r b l rin n k s f o r t vin p p e d s p u r s e a r a Since i n t h i s case the t i p cylinder is machined by the gear-cutting t o o lthe t i p cylinder of the gear blank i s given a machining allowance which may differ according t o t h e gear-cutting method used.
Base tanuent lenuth allowances; dual cone width allowances; Dem. The cumulative error of a tooth system is the common and simultaneous effect of a number of individual errors on the ideal position and geometry of the tooth flanks.
For gears not covered i n the scope it may be necessary i certain circumstances to modify the n allowances and tolerances. This i s performed a s follows: The following are distinguished: Gear blank f o r gear with external t eet h Bearing seating diameter Centre hole Figure The q u a l fin t y of a tooth system depends very l ar gel y on 558405 accuracy of the gear blanks.
For grades P 8 it is recommended that the tip cylinder should be 584005 for setting up the gear blank, or that test flanges should be provided. In connection v i t h the s e l e c t i o n of b a l l b e d n g e i t should be noted t h a t the tolerance allowed f o r t he bearing bores Q i n t h e housing r e l a t i v e t o the tolerance on t he centre distance Ta must be reduced by the amount of the r a d i a l run-out of the b a l diin bearing outer ringe frL.
In t h i s connection i t should be noted i n p a r t i c u l a r t h a ti n the case of disc-shaped gear blanks i n which t h e length of bore i a not s u f f i c i e n t t o support the gear blank during the gear-cutting procese, the end faces serve ae contact faces during the gear-cutting process and hence t h e i r geometrical and position var i at i ons determine t he qual i t y of th e tooth system. I n t h e case of housings made of aluminium a l l o y s and s i m i l a r materials, s u i t a b l e measues should be taken, e.
Tolerances and allowances for housing AB understood in this Standard, t h e t e m housing r e f e r e t o the component connecting the bearings of a p a i r of mating gears.
In this case the permissible axial eccentricity TAa is: The cumulative error can be found by rolling the gear to be tested with a master gear, f o r which purpose the total composite error of the master gear must be known and, where necessary, deducted from the teet result. For any given bearing a l l the s t at i onar y par t e belong t o the housing and a l l the p a r t s r o t a t i n g with the gear belong t o the shaft f o r permissible variat i o n of the “shaft” see Table I columu I O.
The e r r o r t r a c e must remain between the two l i n e s previously drawn which represent the bounda r i e s of t h e tolerance zone. For denomination of contact f aces and of the relevant qual i t y i ndi cessee Figure 1 and 2 ; f o r marking the d i f f e r e n t ear blank shapes, see reference regarding Sup, plementary Sheet 2 i n DIN Sheet I page The face alignment error is designated as pos i t i ve if t he var i at i on i s i n the right-hand dir e c t i o nand negative i f i t i a i n the left-hand di r ect i on with reference t o the design value n of the h e l i x angle Bo.
This i s why permissible v a ri a t i o n s a r e specified for the gear blank i n accordance w i t h the required qua l i t y of the tooth system. I test flanges a r e provi0ed f o r setting up purposes, the permissible radial eccentricity f applies t o these. The ideal involute surface corresponding to the nominal dimension and shown in Figure 4 is outside the boundary involutes 58045 of the negative base tangent dn allowances see a l s o DIN Sheet IFigure I.
Base tannent lenRth allowances; dual cone width allowances; Derm. Base tannent lennth allowances; dual cone width allowances; perm.
Minor var iat i o n s may, however, a r i s e in this connection because the individual allowances have been rounded t o preferred numbers. The c e n tre distance a” i s then reduced each time by the upper and louer allowance of the base tangent length converted t o the r a d i a l direction.
The difference between the upper and the lower allowance of the tip circle ia appended as a minus tolerance.
The following 2 measuring planes a re distinguished: The acceptance for tooth Systeme mainly consists of a cumulative e r r o r testing r o l l testing.
If the c h a r t feed i s operated and a t ra c e drawn corresponding t o t he upper and lower allowance, two concentric c i r c l e s a r e obtained if the recording i a made in pol ar Co-ordinates see Figure 5 and two p a r a l l e l s t r a i g h t lines i f the recording i s made i n rectangular Co-ordinates see Figure 6.
The s l i p gauges a re then removed, t h e two gears ar e mounted on the arbors, brought i n t o cont a c t and r o l l e d one on the other.