A pair of helical gears with any helical angle are installed so that their axes are neither parallel nor intersecting, forming a helical staggered gears transmission, so the staggered axis helical gear transmission is used to transmit motion and power between two staggered axes in space. A single gear is a helical gear, but because the relative positions of the two shafts of the staggered-axis helical gear transmission and the helical gear transmission are different, the transmission characteristics are also different. Next, I will introduce the characteristics and meshing conditions of the staggered shaft helical gear transmission.
First, the meshing conditions of helical staggered gears are introduced. The teeth of the two wheels only mesh in the normal direction, so the correct meshing condition is that the normal modulus and the normal pressure angle of the two wheels should be equal respectively, and they are standard values.
Since the helix angles of the two wheels are not necessarily equal in the transmission, the end face modulus and the end face pressure angle of the two wheels are not necessarily equal, which is the difference between the helical staggered gears transmission and the helical gear transmission.
The second is the design of the gear transmission. The single gear in the staggered-axis helical gear transmission is the helical cylindrical gear, so the calculation formula of the helical cylindrical gear can be used for the calculation of the geometric parameters and dimensions of the two wheels. However, since the axes of the staggered-axis helical gear transmission and the helical gear transmission have different relative positions, the calculation formula of the center distance is different.
Last but not least, is the characteristic of helical staggered gears
1. When the transmission ratio is confirmed, the diameter of the two-wheel indexing circle can be changed by changing the size of the helix angle, so as to meet the requirements of the center distance. When the two-wheel indexing circles are determined, the requirements of the transmission ratio can be met by changing the size of the helix angle.
2. The steering of the driven wheel can be changed by changing the helix angle.
3. During meshing transmission, in addition to relative sliding in the direction of tooth height, there is also relatively large relative sliding in the direction of tooth length, so the gear teeth are easy to wear and the transmission efficiency is low.
4. The two teeth are in point contact during meshing transmission, so the contact stress is large, and the tooth surface is easily crushed, thereby increasing the wear of the gear teeth.
5. Axial force is generated during meshing transmission, and the requirements for bearings are relatively high.
Due to the above characteristics of the helical staggered gears transmission, this kind of transmission is suitable for the environment of transmitting motion or small power.