Basic principles and application scope of worm gear hard tooth surface reducer transmission

Date:2021-07-19 11:10:17

1、 The main parameters of the worm gear reducer are: modulus m, pressure angle, worm direct pass index q, lead angle, number of worm heads, number of worm teeth, tooth tip height index (taken as 1), and backlash index (taken as 0.2).

Among them, the modulus m and pressure angle refer to the modulus and pressure angle of the worm gear shaft surface, that is, the modulus and pressure angle of the worm gear shaft surface, and both are indicator values; The straight axis index q of the worm is the ratio of the modulus m between the diameters of the worm pitch circles.

2、 The calculation of geometric specifications is basically the same as that of cylindrical gears, but many difficulties need to be paid special attention to are: the worm lead angle () is the angle between the broken line of the helical line on the cylindrical body of the worm gear and the middle of the worm inner hole, and is related to the helical angle of the screw. The greater the helical angle of the worm gear, the higher the transmission efficiency. When it is less than the equivalent friction angle between the meshing teeth, the self-locking structure is formed.

The introduction of the worm gear straight through index q is to limit the number of worm gear cutters, so that the diameter of the worm gear indexing circle can be standardized. When m is constant, the larger q, the greater the bending stiffness and compressive strength of the worm shaft; At a certain time, the smaller the q, the larger the lead angle, and the higher the transmission efficiency.

The recommended values for the number of worm heads are 1, 2, 4, and 6. When the smaller value is taken, the reduction ratio is larger and it has self-locking properties; When taking a large value, the transmission efficiency is high.

Unlike cylindrical gear transmission, the reduction ratio of the worm and worm gear organization is different, but the base distance of the worm and worm gear organization is different.

The discrimination method for the rotation of the worm gear in worm gear transmission can be based on the orientation at the meshing point K, the orientation (parallel to the broken line of the spiral), and the material triangle of the velocity vector that should be drawn perpendicular to the center line of the worm gear; You can also use "right-handed worm gear, left-handed worm gear, four thumbs" to distinguish.

3、 The standard for proper meshing of worm gear and worm wheel: 1. The modulus and pressure angle of the worm gear and worm wheel in the center plane diagram are the same, that is, the inner hole modulus of the worm wheel is equal to the axial modulus of the worm gear and is the indicator value; The inner hole pressure angle of the worm gear should be equal to the axial pressure angle of the worm gear and be the indicator value, i.e.==m,==.

2. When the overlap angle of the worm gear is, it is necessary to ensure that the direction of rotation of the worm gear and the helix of the worm gear is the same.

4、 The characteristics of worm gear and worm gear organization can achieve a relatively large reduction ratio, which is more compact than the structure of overlapping shaft bevel gears.

The contact between the two meshing tooth surfaces is linear, and its bearing capacity is much higher than that of the overlapping shaft bevel gear structure.

Worm gear transmission is very different from spiral transmission, as it is a multi tooth meshing transmission, so the transmission is stable and the noise is not significant.

Capable of self-locking.