RV75 Worm Gearbox Overview
The RV75 worm gearbox is used in conveyors, packaging machines, food machinery, mixers, material handling and other industrial equipment. Its right-angle shaft arrangement provides compact speed reduction where machine space is limited.
| Specification | RV75 / NMRV075 |
|---|---|
| Gearbox size / center distance | 75 mm |
| Gear type | Worm gear |
| Common output bore | Ø28 mm |
| Ratios shown in supplied material | 5, 7.5, 10, 15, 20, 25, 30, 40, 50, 60, 80, 100 |
| Motor power examples shown | 0.55–4 kW |
| Housing | Aluminum alloy |
| Motor connection | IEC round flange or compatible custom square flange, subject to configuration |
RV75 Dimensions
The supplied drawing shows preliminary envelope references of approximately 112 mm, 172 mm and 205 mm. These values help with an initial replacement comparison, but input flange dimensions change with the motor shaft, IEC frame or custom adapter.
Before replacing an existing gearbox, compare:
- 28 mm output bore, keyway and tolerance
- Input bore and motor shaft diameter
- Flange outside or edge length and pilot bore
- Diagonal bolt spacing and mounting-hole pattern
- Overall gearbox height, width and installation clearance
- Mounting position and breather arrangement
What Is the RV75 Output Bore?
A common RV75 hollow output bore is Ø28 mm. Check the driven shaft diameter, key size, keyway position and fit tolerance before ordering. A nominal bore alone is not enough to confirm interchangeability.
RV75 Ratios and Output Speed
The supplied material lists 5, 7.5, 10, 15, 20, 25, 30, 40, 50, 60, 80 and 100. Confirm availability and rated performance for the selected unit, especially at the lowest ratio.
Actual speed follows the loaded motor speed, frequency and slip.
| Ratio | Example with 1400 rpm motor |
|---|---|
| 20:1 | Approximately 70 rpm |
| 30:1 | Approximately 47 rpm |
| 50:1 | Approximately 28 rpm |
| 100:1 | Approximately 14 rpm |
How to Select the RV75 Ratio
Start with the motor rated speed and the required machine speed. If a 1400 rpm motor must drive the machine at about 47 rpm:
A 30:1 RV75 is therefore a ratio to evaluate, not a complete gearbox selection.
Then verify continuous and peak torque, service factor, operating hours, starts per hour, thermal capacity and any radial load from a pulley or sprocket. The worm gearbox service-factor guide explains these duty checks.
RV75 Motor and Round-Flange Options
The supplied chart illustrates these motor-matching examples:
| Input bore | Motor power examples | Flange diameter examples |
|---|---|---|
| 19 mm | 0.55 / 0.75 kW | Ø120 small / Ø200 large |
| 24 mm | 1.1 / 1.5 kW | Ø140 small / Ø200 large |
| 28 mm | 2.2 / 3 / 4 kW | Ø160 small / Ø250 large |
These are illustrated combinations only. Confirm the IEC frame, motor shaft, pilot diameter, bolt pattern and rated duty before purchase. See the SMK three-phase motor page and motor-to-gearbox matching guide.
Square Flanges for Stepper or Servo Motors
The image also shows square adapter examples with flange edge lengths from 80 to 130 mm, pilot bores from 70 to 110 mm, diagonal bolt spacing from 90 to 145 mm and input bores from 19 to 24 mm. A custom adapter must be confirmed from the actual motor drawing; do not select it from motor type alone.
RV63 vs RV75
RV75 has a 75 mm center distance and a common 28 mm output bore, making it the next larger size after the 63 mm class. Compare the RV63 dimensions and 25 mm bore guide when deciding whether the existing shaft and mounting interface require size 63 or size 75. The broader NMRV size guide covers RV25 through RV150.
Typical RV75 Applications
RV75 reducers are commonly considered for conveyors, packaging lines, mixers, food-processing equipment, agricultural machinery and industrial automation. Conveyor selection should also consider drum diameter, belt speed, conveyed load, incline and starts per hour; see the conveyor gearbox selection page.
Need an RV75 Replacement?
For an existing RV75, NMRV075 or similar worm reducer, send:
- Gearbox and motor nameplate photos
- Motor power, voltage, frequency and rated speed
- Existing ratio or required output speed
- Output bore, keyway and shaft dimensions
- Input flange and bolt-pattern dimensions
- Mounting position and application
- Required continuous and peak load information
Conclusion
RV75 selection starts with the required ratio and 28 mm output connection, then continues with torque, service factor, motor power, input flange and mounting checks. Use the diagram for preliminary comparison and obtain an approved drawing before finalizing the machine interface.