The main characteristics of worm gear and worm drive are as follows:

Large transmission ratio can be obtained, which is more compact than the staggered helical gear mechanism.

2. The meshing tooth surfaces of two wheels are in line contact capacity, and the load-carrying of the two wheels is much higher than that of the staggered gear mechanism. Helical gear mechanism.

3. Worm transmission is equivalent to spiral transmission, which is multi-tooth meshing transmission, so the transmission is smooth and the noise is very low.

<4. Self-locking. When the guide angle of the worm is less than the equivalent friction angle between the meshing gear teeth, the mechanism has self-locking If the self-locking worm mechanism is used in lifting mechanism, its reverse self-locking can play a safe protection role.

5. The transmission efficiency is low and the wear is serious. In worm and worm meshing Transmission, the relative sliding speed between meshing gear teeth is high, so the friction loss is large and the efficiency is low. On the other hand, the relative sliding speed makes the tooth surface worn serious and heated serious. In order to dissipate heat and reduce wear, materials with high friction and wear resistance and good lubric They are often used, which are more expensive, so the cost is higher.

Basic parameters of worm gear and worm: modulus m, pressure angle, worm diameter coefficient q, lead angle, number of worm heads, number of turbine teeth, top height coefficient (1) and top clearance coefficient (0.2). Among the m, modulus and pressure ref angle Er to the modulus and pressure angle of the worm axle, that is, the modulus and pressure angle of the turbine end face, and they are all standard values; the worm diameter coefficient q is the ratio of the worm indexing circle diameter to its modulus M.

Worm drive is composed of the worm and worm wheel, and worm is the main part in general. E threads, worm has right-handed and left-handed worm drive, which are called right-handed worm and left-handed worm respectively. There is only on e helix on the worm called a single-head worm, that is, the worm revolves around, the worm wheel revolves a tooth, if there are two helixes on the worm, it calls a double-head worm, that is, the word M revolves around, the worm wheel revolves two teeth.

When worm is active, efficiency_ = Tan gamma/tan (gamma+v), efficiency_increase with the increase of lead angle gamma of worm helix, but usually gamma< 30 degrees; reducing equivalent friction angle V can also improve efficiency_. In multi-stage transmission of gear and drive Worm drive, if the speed is not too high, worm drive is usually placed in the high-speed stage to increase relative sliding speed Vs and then reduce it. Measure friction angle V to improve efficiency.

Practice has proved that when steel worm is used to cooperate with bronze turbine, the turbine mechanism has excellent friction reduction and F. The total efficiency of worm transmission is equal to the transmission efficiency of worm helical pair, the bearing efficiency of supporting worm wheel and worm, and the transmission efficiency of splashing oil lubrication. TG (lead angle) / TG (lead angle + equivalent friction angle)

< p > TG (lead angle) = (number of spiral head of worm * modulus) / diameter of worm indexing circle

< p > < p > From the above three formulas, it can be seen when the diameter of worm indexing circle, TG (angle), lead angle, lead angle equivalent friction But because of the existence of equivalent friction angle, TG (lead angle + equivalent friction angle) decreases faster than TG (lead angle + equivalent friction angle), the transmission efficiency of worm helical pair, and finally the total worm transmission efficiency

< p > So, the dividing circle diameter of worm is closely relat The plane double enveloping hourglass worm reducer of worm gear reducer is an advanced heavy-duty transmission device, which has such excellent characteristics as large load-carrying capacity, high transmission rate and long service life. It is the best choice to replace other worm.