The following are the main differences between the old and new worm gearboxes:
1. Material & Performance
Compared with the aluminum bronze (CuAl) worm gear used in the old gearbox, the new worm gear is made of tin bronze (CuSn). The tin bronze worm gear enables the gearbox to deliver higher torque and strength, smoother transmission, and lower noise.
2. Dimensions
As shown in the figures below, we detail the dimensional differences between the old and new models.
2.1 NMRVS30 vs. NMRV30
The only change in the 30 series is the mounting hole spacing at the input end of the gearbox. This change does not affect compatibility with NEMA 23 motors under standard mounting conditions.
2.2 NMRVS40 vs. NMRV40
As shown in the figure, the changes to the 40 series are as follows:
① The distance between the input flange face and the output shaft is shorter; this change reduces the overall length of the new gearbox by 1 mm.
② The pilot diameter of the motor input mounting hole is larger; the outer diameter of the input mounting hole on the new gearbox has increased by 1 mm compared to the old model. This does not affect compatibility with NEMA 34 motors under standard mounting conditions.
2.3 NMRVS50 vs. NMRV50
The dimensional changes in the 50 series are mainly reflected in the following points:
① The distance between the input flange face and the output shaft is greater; the overall length of the new gearbox increases by 3 mm.
② The pilot diameter of the motor input mounting hole is larger; the outer diameter of the input mounting hole on the new gearbox has increased by 1 mm compared to the old model. This does not affect compatibility with NEMA 42 motors under standard mounting conditions.
③ The input flange face is larger; the input flange of the new gearbox measures 112 × 112 mm. Compared to the old model, the input flange is 1 mm larger on each side.
④ The housing width is smaller; the width of the new gearbox is reduced by 0.5 mm.
⑤ The distance between the mounting holes on the underside of the gearbox is smaller; the spacing on the new gearbox has been reduced by 1 mm. Since the mounting holes are slotted, this change actually improves compatibility.
Based on the dimensions above, the input motor requirements for the new gearbox remain the same as those for the old model, and the new gearbox remains fully compatible with the same input motors. The changes to the housing dimensions do not affect the overall performance of the gearbox.
3. Availability of Old-Model Gearboxes
The old-model gearbox will be discontinued once current stock is depleted. If you require the old model, please contact us to place a pre-order. Note that a minimum order quantity applies.