Helical gear will produce axial force during transmission, which is caused by the inclination angle of helical gear. Axial force may have adverse effects on transmission system and bearings, so measures need to be taken to eliminate or reduce axial force. Here are some common methods:
1. Using symmetrical helical gears:
By changing the inclination angle of the helical gear, the helical gear is symmetrical, and the generation of axial force can be reduced.
Symmetrical helical gears have two identical inclination angles, so that the axial forces on both sides cancel each other out.
2. Using reverse helical gear:
Reverse helical gear is a special kind of helical gear, and its inclination direction is opposite to the transmission direction.
When the reverse helical gear and the common helical gear are paired, their axial forces can cancel each other out.
3. Using helical gear coupling:
Helical gear coupling is a special coupling, in which the helical gears have opposite inclination angles.
Helical gear coupling can cancel each other’s axial forces, thus reducing the impact on the transmission system.
4. Use axial force balancing device:
The axial force balancing device can balance the axial force generated by the helical gear by introducing a balancing shaft or using devices such as springs.
These devices can reduce the influence of axial force on the transmission system and bearings.
It is necessary to choose a suitable method to eliminate or reduce the axial force generated by helical gears according to the specific application situation.
In the design process, the influence of axial force can be further reduced by optimizing the geometric parameters of helical gears and increasing lubrication and damping measures.
The axial force of helical gear can be calculated by the following formula:
Fz = Ft * tan(α) / (cos(β) * cos(γ))
Fz is the axial force,
Ft is the tangential force (generated by the transmission torque),
α is the pressure angle of the helical tooth,
β is the pressure angle of the gear,
γ is the helix angle of the gear.
It should be noted that this formula is obtained under the ideal condition that the friction coefficient of gears is 1. In practical application, the friction coefficient may be different, so it can be modified according to the actual situation. In addition, the angle unit in the formula is usually radian, so it needs to be converted according to the specific situation.