What is the working principle of WPWDKS120-20 worm gear reducer?

Working principle of WPWDKS120-20 worm gear reducer (detailed explanation combined with model characteristics)

WPWDKS120-20 belongs to the WP series two-stage worm gear reducer (model disassembly: W = worm, P = Archimedean/planar enveloping worm, D = two-stage transmission, K = hollow shaft output, S = flange installation, 120 = center distance 120mm, 20 = total transmission ratio 20). Its core working principle is through 'space staggered shaft transmission of worm gear meshing' Achieve deceleration and torque increase, while using the two-stage series structure to optimize the transmission ratio, and finally convert the high-speed and low-torque of the motor into the low-speed and high torque required by the equipment. The following is a detailed description of the core mechanism, structural coordination, and transmission process, combined with the model parameters:

1. Core working mechanism: worm gear meshing transmission (space staggered shaft meshing)

1. Basic meshing principles

The essence of the worm gear is 'a special form of helical gear transmission'. The axes of the two are intersecting at 90° in space (no intersection, non-parallel), and power transmission is achieved through sliding friction + rolling friction on the tooth surface:

Worm: Equivalent to 'right-hand/left-hand helical gear', the number of teeth is 1-4 teeth (called 'number of heads', WPWDKS120-20 commonly used worm head number z1=2 or 4), the helix angle is usually 5°-15°, the tooth surface pushes the worm gear teeth like a 'screw' when rotating;

Worm gear: Equivalent to 'a nut driven by a screw', the tooth surface is arc-shaped (adapted to the worm helical surface), the number of teeth z2 is usually 20-80 teeth (the number of teeth of the WPWDKS120-20 worm gear z2=40 or 80, and the total transmission ratio is achieved by matching the number of worm heads to achieve a total transmission ratio of 20);

Key features: When meshing, the worm is active and the worm gear is driven, and power can only be transmitted from the worm to the worm gear (reverse self-locking, that is, the worm gear cannot drive the worm, which can realize equipment shutdown and positioning without the need for additional braking devices).

2. The core logic of decelerating and increasing torque (formula + model example)

(1) Reduction ratio calculation (two-stage transmission ratio = product of two-stage single-stage transmission ratio)

WPWDKS120-20 is a double-stage worm gear in series (two single-stage worm gear mechanisms are connected front and back), and the calculation formula of the total transmission ratio i is:

i = i1 × i2 = (z21 / z11) × (z22 / z12)

Symbol explanation: i1 and i2 are the first and second-stage single-stage transmission ratios; z11 and z12 are the number of first and second-stage worm gears; z21 and z22 are the number of first and second-stage worm gear teeth;

Model example: WPWDKS120-20 The total transmission ratio i=20, the common configuration is the first stage i1=5, the second stage i2=4 (such as z11=2, z21=10; z12=2, z22=8), or i1=4, i2=5 (z11=2, z21=8; z12=2, z22=10), finally achieving a total transmission ratio of 5×4=20.

(2) Conversion of speed and torque (ignoring efficiency loss)

Speed ​​relationship: output speed n2 = input speed n1 /i

Example: The motor input speed n1=1450rpm (ordinary 4-pole motor), then the output speed n2=1450/20=72.5rpm (in line with the rated output speed range of this model 60-80rpm);

Torque relationship: output torque T2 = input torque T1 × i × η

Example: Motor input torque T1=15N·m (1.5kW motor), reducer transmission efficiency η=0.75 (two-stage worm gear efficiency is usually 0.7-0.8), then output torque T2=15×20×0.75=225N·m (matching WPWDKS120-20 rated output torque 200-250N·m);

Core conclusion: The larger the transmission ratio, the lower the output speed and the greater the output torque (provided that the input power remains unchanged). This is also the core value of the reducer 'deceleration and torque increase'.

2. Model-specific structural coordination: structural advantages of two-stage transmission (designed in combination with WPWDKS120-20)

1. Core component composition (adapted to 120mm center distance)

First-stage worm gear : center distance a1=80mm (small center distance, achieving preliminary deceleration), worm shaft diameter φ30-35mm, worm gear indexing circle diameter φ160-180mm;

Second-stage worm gear : center distance a2=120mm (main center distance, achieving secondary deceleration), worm shaft diameter φ40-45mm, worm gear indexing circle diameter φ200-220mm;

Support structure : The two-stage worm is supported by deep groove ball bearings (first stage 6306/6307, second stage 6308/6309) to ensure axial movement ≤ 0.1mm and radial runout ≤ 0.08mm; the output end is a hollow shaft (aperture φ50-60mm) with a flange mounting seat (S-type design), and the adapting equipment is fixed.

2. Advantages of double-stage transmission (compared to single-stage)

Larger transmission ratio : the maximum transmission ratio of the single-stage worm gear is about 80, and the two-stage can easily reach more than 1000. The 20 transmission ratio of WPWDKS120-20 is distributed through two stages, which can reduce the single-stage meshing pressure (avoiding the overload of the single-stage worm gear tooth surface);

The speed gradient is gentler : the high-speed motor (1450rpm) decelerates to 290rpm (1450/5) through the first stage, and then decelerates to 72.5rpm through the second stage, reducing tooth surface impact friction, lowering oil temperature, and extending service life;

: Under the 120mm center distance design, the two-stage series connection is smaller than the single-stage large transmission ratio structure, and is suitable for scenarios with limited installation space (such as small conveyor lines, packaging machinery).