Worm and wheel

Worm and wheel

Worm and wheel(in the form of a screw gear) (a spur gear is similar in appearance, and it is also called a worm wheel) of meshes with a worm gear, a gear management. The term often worm, worm gear, or as a unit worm gear worm drive imprecise term used to refer not to be confused by.

Explanation

Using a worm and wheel gearbox designed a simple spur gears considerably smaller than the one at 90 ° to each other and will focus his campaign. With a single start worm, worm, each 360 ° turn, only one of the gear teeth of the worm gear. Therefore, regardless of the size of the worm (despite sensible limits Engineering), the gear ratio "1 - - The size of the worm gear is". Given a single start worm, a 20 tooth worm gear speed will be reduced by the ratio of 20: 1 (good engineering practices designed to be so small) spur gears, 12 teeth with a gear ratio of 20 to achieve the same with a 240 tooth gear will be matched: 1. diametrical pitch (DP) had every reason to be in gear, the same, then, 20 the gear teeth of the gear teeth 240 in terms of physical size, insect management is fairly small in volume.

Types

That can be used in a worm and wheel are three different types.

NEXT is the first worm gear. If the worm or worm wheel or around the frame machined from a throat, or groove, is not required. A sore throat is the second worm wheel worm gear are. The final type of sore throat which double worm gears gears are. Most of this type of gearing loading can support.

A-enveloping (hourglass) worm from both ends toward the middle portion of one or more teeth and increases in diameter.

Double enveloping worm gearing worm gears mated with fully-enveloping enveloping contain bugs. It is also known as globoidal worm gearing.

Direction of transmission

Usually a single start (spiral) is used when the worm and wheel, the friction between the involved due to the large reduction ratio, using the contrast with the gear trains, transmission (output shaft vs. input shaft) direction is not reversible. The input to eliminate any possibility of driving the output is desired it can also be an advantage. A multistart worm (multiple spirals) is used if the ratio is reduced

accordingly and be able to drive the worm gear as a worm and worm gear braking effect may need to be .

Worm gear drive which can not be self-locking worm gear is configured. A Worm and wheel and gear lead angle, pressure angle, and the friction coefficient depends on whether it will turn itself; however, the lead angle of the tangent of the friction coefficient is lower than a worm and gear will turn itself that is to say is almost correct.