Interlocking
| Toothing - related terms | |
|---|---|
| One-sided toothing | Perforation |
| Splines of drivers | Serration , spline , Hirth serration |
| Toothing of gears | Involute toothing , cycloid toothing ; Helical gearing |
A toothing in the art, the shaping of a workpiece with teeth, tines or wedges for preparing a compound, for increasing the friction or as a separating tool . The term toothing can refer to the shape and arrangement as well as the manufacture of the teeth. Toothing of saws in both meanings is also called toothing .
General
Opposing gears with form-fitting interlocking tooth flanks are suitable for the transmission of power , torque or rotational speed, as is the case with gearwheels and other gear parts. Splines as rigidly interlocking gears can have the purpose of a fixed but detachable coupling , as in the case of the Hirth gearing .
The interlocking of beams , planks and girders is an old technique used by carpenters to increase the length and load-bearing strength of wooden components. Today machine-made finger jointing is common.
In masonry construction, interlocking means the creation of a connection point in the masonry bond for a wall to be built later, which is at an angle of 90 ° to the interlocked wall. A distinction is made between perforated teeth, vertical and horizontal teeth.
One-sided serrations are suitable for increasing friction ( checker plate , knurling ), as a gripping tool ( rake , comb , toothed spatula , spoon of an excavator) or as a cutting part of a cutting tool for machining workpieces ( saw , rasp , file , milling tool ), in which the Teeth serve as cutting wedges. The knurling and some milling tools are examples of cross-cut teeth.
There is also talk of toothing without a form fit with rough surfaces (such as sandblasting ) and textiles . When joining, this toothing is distinguished from adhesion as static friction . In the case of nonwovens and felts , the static friction is increased by entangling the fibers. Interlocking with barbs enables the zip or Velcro fastener .
Toothings for connection or to increase friction also occur in nature: the true beetle cicada has teeth on its legs that synchronize their movement.
Splines and gears
The machine elements with splines or splines include connecting elements with serrations and splines which, for example, as drivers, allow at most one axial movement to one another, such as the internal multi-tooth profile for screw head drives. The majority of these applications belong to the shaft-hub connections .
In addition, there are positively interlocking parts that move against one another, such as gear wheels, racks and worm wheels . Racks can be combined with gears or worm gears to convert a linear movement (forward - backward) into a rotating one, or vice versa as with the rack railway . Gears can be combined with other gears, racks or worm gears. In addition, in combination with toothed wheels, there are dimensionally stable, but elastically deformable toothed belts , which, like a crawler, turn the frictional connection of the V-belt into a positive connection .
The geometry of movable tooth flanks should be designed in such a way that the transmission of the forces (the torque in the case of a gearwheel ) takes place with as little friction as possible in accordance with the law of gearing . The touching tooth flanks of roller gears should roll off one another (with worm gears they slide). According to the shape of the tooth flanks gearing types are distinguished: Most commonly found in mechanical engineering is the involute . Gears with large gear ratios, such as those used in clockworks, have cycloidal gears . In addition to the straight teeth parallel to the axis of rotation, there are also helical teeth to compensate for axial forces, such as herringbone teeth, as well as curved or spiral teeth.
Manufacturing
See also: Gear # Manufacturing
The manufacture of splines and gears is considered to be complicated, which is why special processes have been developed for it. This includes the Wälzhobeln , gear shaping and hobbing , the latter being used in volume production and the first two because of lower productivity, but higher flexibility for individual pieces and small series. The finishing is done in all cases by generating grinding . Instead of planing, slotting or milling, drop forging can also be used for the raw parts. Generating and whirling (which is related to milling) are suitable for worm gears .
literature
- Alfred Böge (ed.): Vieweg Handbuch Maschinenbau , Vieweg, Wiesbaden 2007, pp. O 83 – O 94. ISBN 978-3-8348-0110-4
- Ernst Widmer: Milling and toothing , Springer, Basel 1979. ISBN 978-37643-1134-6
- Herbert Wittel, Dieter Jannasch, Joachim Voßiek, Christian Spura: Roloff / Matek. Machine elements. Standardization, calculation, design. , Springer Vieweg, Wiesbaden 2019. ISBN 978-3-658-26279-2
Individual evidence
- ^ Karl Ferdinand von Ehrenberg: Baulexikon , Sauerländer, Frankfurt am Main 1840, p. 892.
- ↑ Klaus-Jürgen Schneider et al. (Ed.): Baulexikon , Beuth 2016. ISBN 978-3-410-24655-8 URL: https://baulexikon.beuth.de/VERZAHNUNG.HTM
- ↑ Eberhard Pauksch et al .: Zerspantechnik , 12th edition, Vieweg, Wiesbaden 2008, pp. 185f. ISBN 978-3-8348-0279-8
- ↑ Chokri Cherif (ed.): Textile materials for lightweight construction , Springer, Heidelberg 2011, p. 469. ISBN 978-3-642-17991-4