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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In the came of instrument drives it is recommended, particularly when mounted overhung, that ball bearings with increased radial clearance ehould be used and proloading applied.
The e r r o r i n a x i a l parallelism i e designated by Spa. 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 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.
I test flanges a r e provi0ed f o r setting up purposes, the permissible radial eccentricity f applies t o these. DIN tol f cylindr They should be taken from the Tables i n Section 6 t o s u i t the gear f dln t selected grade and tolerance zone. Base tanuent lenuth allowances; dual cone width allowances; Dem.
Minor var iat i o n s may, however, a r i s e in this connection because the individual allowances have been rounded dih o preferred numbers. 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. 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, 5405 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.
I the tip circle tip cylinder is used for setting up the gear blank on the gear-cutting f machine, the radial eccentricity of the gear blauk according to Table 4 should be observed.
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. The ideal involute surface corresponding to the nominal dimension and shown 5840 Figure 4 is outside the boundary involutes because of the negative base tangent length allowances see a l s o DIN Sheet IFigure I. The reference axis f o r the radial eccentricity is the axis of the mounting bore see Figure 1 or the axis of the gear seating diameter see Figure 2 or the axis of the two centre holes see Figure 3.
Like the base tangent length allowances, compliance with the dual cone width allowances can a l s o be determined by t h e dual flank r o l l t e s t i n The procedure i s the same as t h a t described under Section 4.
In t h i s dun 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 588405 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.
The following are distinguished: Aw irI 2 lana, 50 lover allovanc. Base tanuent lenRth allowancea; dual cone width allowances; Dem. Base tannent lenRth allowances; dual cone width allowances; Derm. I f one of these requirements i s over-stepped the new dinn which r e s u l t regarding clearances, accuracy of transmission, tooth engagement conditions, etc. The difference between the upper and the lower allowance of the tip circle ia appended as a minus tolerance.
In this case the permissible radial eccentricity for the tip circle should be taken from Table 3.
DIN – European Standards
Permissible radial eccentricits for tip cylinder when this is n o t used for settinn UE Table 4 Permissible radial eccentricity f o r. Recommendation f o r t h i s purpose i a given in column 4 t o 20 i n Table 1. The following 2 measuring planes a re distinguished: The tolerances and allowances etated’in the following Tables apply to gears according to D M Sheet 1, Section 2.
They a r e intended t o serve t h e designer as a check l i s t of a l l the points which must be taken i n t o account when choosing a gear f i t. Base tangent length allowances and t h e i r boundary involutes The base tangent length allowances a r e r e l a t e d t o the tooth thickness allowances as follows: 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 l bearing outer ringe frL.
The c e n t re distance allowances apply t o housings with gears according t o Dl3 Sheet 1, Section 2.
This dimension must not be entered in the drawing redundant dimensioning; see DIN Sheet 3. The centre distance a” can be s e t by placing the appropriate s l i p gauges between t he two mounting a rb o rs or the individual arbors.
The t o t a l composite error according t o Section 4. The values specified relate to the bearing when inetalled. Since the dual flank roll testing is generally carried out as a final inspection, and since it cannot be performed until the teeth have been finished, base tangent length and dual cone width allowances have been specified during dih measurement of tooth thickness.