Worm and worm wheel mechanism is used to traner between two crisscross axis of sports and power. Worm gear and worm in it in gear with plane between equivalent to rack, and the worm and and screw shape similar
Basic parameters
Module m, pressure Angle, worm diameter index q, guide process Angle, regardless of the worm gear, gear, worm top high coefficient (1) and take the top gap coefficient (for 0.2). Among them, the module m and pressure Angle refers to the worm shaft module and pressure Angle, ., the end of the worm gear module and pressure Angle, and are standard; Worm diameter index q worm dividing circle diameter for its modulus of the ratio of the m.
classification
Worm gear and worm generally there are these series: 1, WH series worm gear and worm reducer: WHT/WHX/WHS/WHC 2, CW series worm gear and worm reducer: CWU/the CWS/CWO 3, reference series worm gear and worm reducer: WPA/WPS/WPW/WPE/WPZ/WPD
Worm gear and worm right of meshing conditions
1. The worm and worm among plane within the modulus and pressure Angle, namely the worm gear were equivalent modulus is equal to the end of the worm shaft side modulus and for standard; Worm gear of end pressure Angle should be equal to the worm shaft side pressure Angle and standard for, namely = = m, = =
2. When the worm crisscross Angle, still need to ensure thats too, and worm gear and worm helical screw to must be identical.
Four, geometry size calculation and cylindrical gears basic same, several problems that should pay attention to
1. The worm process Angle () is the worm indexing columns helical on the tangent and end the Angle between the worm, and screw spiral Angle for, the relationship between the worm is spiral Angle, high transmission efficiency, less than the paired gears when between friction Angle, agency equivalent since the lock.
2. The worm diameter index q is introduced to limit the number of worm gear hob, make the worm dividing circle diameter standardized the m a, q is big, and the worm shaft stiffness and strength increases accordingly; A small, q is guide process Angle is increased, the transmission efficiency increase.
3. Regardless of the worm recommended value is 1, 2, 4, 6, take small value, its velocity ratio of big, and has since lock sex; Take great value, high transmission efficiency.
4. The worm gear and worm of worm gear in the judgement of the steering, this method can mesh point K place according to the direction, the direction of parallel to the helix (tangent) and should be perpendicular to the axis velocity vector triangle worm gear painting to judge; Also can use "worm dextral left hand to hold the right hands, levorotatory worm, four thumbs" refers to will judge.
Worm and worm wheel mechanism characteristic
1. Can get a great transmission ratio of than crisscross the helical gear shaft, compact bodies
2. Two gear tooth surface for line contact between, its carrying capacity and much higher than the crisscross shaft inclined gear institutions 3. The worm drive, which is equivalent to screw transmission gear meshing transmission, the stable transmission, the noise is small
4. The lock with sex. When the process is less than the worm gear meshing Angle between the equivalent of the friction Angle, agencies have since the lock, and it can realize the reverse of that locks, only by the worm gear and worm drive, and not by the worm gear and worm drive. As in the heavy machinery used in the organization, its reverse worm lock locking sex but up security role.
5. The transmission efficiency is low, the severe wear. Worm gear and worm drive, meshing gear meshing of the relative speed between sliding friction loss is big, so, the low efficiency. On the other hand, relative sliding speed ambassador tooth face severe worn, heating, cooling and serious in order to reduce wear, often the price is relatively high of reducing friction with the abrasion resistance of better materials and good lubrication device and high cost worm axial force is bigger