Judging the axial force direction of helical cylindrical gear by left-right hand rule

"? "Law to grasp the thread? : "The left screw uses the left screw and the right screw uses the right hand. Grasp the shaft of the driving wheel, and the other four fingers represent the direction of rotation except the thumb.

The thumb points to the direction of the driving shaft towards the force, and the direction of the driven shaft towards the force is opposite and equal to that of the driving shaft. "This rule only applies to driving wheels.

Extended data:

In order to improve the stability of transmission and reduce impact vibration, it is better to have more teeth, and the number of teeth of the pinion can be z 1=20~40. Open (semi-open) gear transmission, because the gear teeth are mainly worn, in order to make the gear not too small, it is not advisable to choose too many teeth for the pinion, and it is generally appropriate to use z 1= 17~20.

At the tangent point P of the pitch circles of two gears, the acute angle formed by the common normal of the two tooth profile curves (that is, the stress direction of the tooth profile) and the common tangent of the two circles (that is, the instantaneous motion direction at point P) is called the pressure angle. For a single gear, it is the tooth angle. The pressure angle of standard gear is generally 20 ". In some cases, α = 14.5, 15, 22.50 and 25 are also used.