Adding an intermediate wheel uses the outer ring to achieve transmission to change the direction.
The rotation of a gear is to drive the rotation of another gear, and to drive the rotation of another gear, the two gears must be connected to each other. So what you can see here is that when one gear turns in one direction, the other gear turns in the opposite direction, which changes the direction of the force. When the chain rotates, when you ride a bicycle, you can easily find that the rotation direction of the gear is consistent with the direction of the chain, and the rotation direction of the small gear and the large gear is also the same, so it should not change the direction of the force.
Gears are mechanical transmissions that use the teeth of two gears to mesh with each other to transmit power and motion. According to the relative positions of the gear axes, they are divided into parallel axis cylindrical gear transmission, intersecting axis bevel gear transmission and staggered axis helical gear transmission to change direction.
Gear transmission generally has a high speed. In order to improve the stability of the transmission and reduce impact vibration, it is better to have more teeth. The number of teeth of the pinion can be z1=20~40. In open (semi-open) gear transmission, since the gear teeth are mainly due to wear and failure, in order to prevent the gear from being too small, the pinion gear should not use too many teeth. Generally, z1=17~20 is recommended.
At the tangent point P of the two gear pitch circles, the acute angle formed by the common normal of the two tooth profile curves (i.e., the force direction of the tooth profile) and the common tangent of the two pitch circles (i.e., the instantaneous movement direction at point P) is called Pressure angle, also called mesh angle. For a single gear, it is the tooth profile angle. The pressure angle of standard gears is generally 20″. In some cases, α=14.5°, 15°, 22.50° and 25° are also used.
Post time: Sep-23-2023