What is an NBR worm gear reducer?
The NBR worm gear reducer is a compact reducer with worm gearing, designed for industrial applications requiring low output speed and high torque. The NBR worm gearbox range covers nine standard sizes — from NBR030 to NBR150 — with input power from 0.06 to 15 kW and gear ratios from 5 to 5,000 (compound configurations). Nibora Ltd is the official distributor of NBR gearboxes in Bulgaria, maintaining full in-stock availability of all sizes and ratios at our warehouse in Pleven.
The worm gear mechanism provides a self-locking effect at gear ratios above 20:1, eliminating the need for additional brakes in vertical applications. The gearboxes are suitable for conveyor systems, screw conveyors, packaging machines, construction equipment and food processing.
Series and Technical Data
| Size | Weight (kg) | Input Power (kW) | Max Radial Force Fr2 (N) | Output Shaft | Gear Ratio i |
|---|---|---|---|---|---|
| NBR 030 | 1.2 | 0.06 – 0.37 | 3 490 | Ø14 H8 | 5 – 80 |
| NBR 040 | 2.3 | 0.06 – 0.55 | 3 490 | Ø18 H8 | 5 – 100 |
| NBR 050 | 3.5 | 0.06 – 0.75 | 4 840 | Ø25 H8 | 5 – 100 |
| NBR 063 | 6.2 | 0.09 – 1.10 | 6 270 | Ø25 H8 | 5 – 100 |
| NBR 075 | 9.0 | 0.18 – 1.50 | 7 380 | Ø28 H8 | 5 – 100 |
| NBR 090 | 13.0 | 0.25 – 2.20 | 8 180 | Ø35 H8 | 5 – 100 |
| NBR 110 | 35.0 | 0.37 – 9.20 | 10 320 | Ø42 H8 | 5 – 100 |
| NBR 130 | 48.0 | 0.55 – 11.0 | 13 500 | Ø45 H8 | 5 – 100 |
| NBR 150 | 84.0 | 1.10 – 15.0 | 18 000 | Ø50 H8 | 5 – 80 |
| Configuration | Ratio range i |
|---|---|
| NBR 030/040 | 5 – 5 000 |
| NBR 030/050 | 5 – 5 000 |
| NBR 030/063 | 5 – 5 000 |
| NBR 040/075 | 5 – 5 000 |
| NBR 040/090 | 5 – 5 000 |
| NBR 050/110 | 5 – 5 000 |
| NBR 063/130 | 400 – 5 000 |
| NBR 063/150 | 150 – 5 000 |
Mounting and configuration
Mounting Configurations
NBR gearboxes are available in six standard mounting configurations, compatible with IEC motors (PAM flange B5 and B14). All versions have a hollow output shaft with H8 tolerance.
| Code | Description (EN) |
|---|---|
| FA | Foot mount – horizontal output (B3) |
| FB | Foot mount – horizontal output, reverse |
| FC | B5 flange – 4 holes |
| FD | B5 flange – alternate orientation |
| VS | Vertical input shaft (motor below) |
| NBRS | Low-speed side shaft (tandem mounting) |
Accessories and Compound Configurations
- PC063 / PC071 / PC080 / PC090 – pre-reducers for additional speed reduction (i = 2.42–3)
- NBRS series – extended low-speed shaft version for tandem mounting
- Output shafts (AS / AB) – single and double output for direct mounting of driven elements
- Torque arm – for hollow shaft versions without floor support
- Input shaft cover
- B5 and B14 input flanges for IEC sizes 056–200
Why NBR
Key Advantages
- Self-locking at i > 20:1 – no additional brake needed for vertical mounting
- Compact design for high torque – optimised power-to-weight ratio for tight installations
- Wide gear ratio range – from i=5 to i=5,000 in compound configurations
- IEC motor compatibility – PAM flange for easy motor replacement without adapters
- Hollow output shaft (H8) – direct mounting of driven elements without additional couplings
- Lifetime lubrication – no periodic oil change required under standard conditions
- All 9 sizes in stock in Pleven – fast delivery within 24–48 hours across Bulgaria
- Competitive price point – NBR own brand meeting European standards
Typical Applications
- Conveyor systems and roller tables
- Screw conveyors and dosing systems
- Packaging and filling machines
- Lifting mechanisms (hoists, valves, gates)
- Food and pharmaceutical processing
- Construction machinery and mixers
- Ventilation drives with adjustable speed
- Agricultural machinery (grain handling, pelletising)
NBR Dimensions
Download NBR Dimensions ↓NBR Specifications
Download NBR Specifications ↓Check availability by specification
| Size | Ratio i | PAM flange | Mounting | Availability |
|---|
No matching gearbox in stock — contact us for a custom configuration.
The data above is for guidance only. For the correct choice, please consult our specialist by phone - +359 64 681 058
The data above is for guidance only. For the correct choice, please consult our specialist by phone - +359 64 681 058
| D H8 | b | t |
|---|---|---|
Possible motor combinations
| P1 (kW) | Motor | n2 (rpm) | M2 (Nm) | f.s. | Fr2 (N) | Motor |
|---|
Frequently Asked Questions (FAQ)
What gear ratios are available for NBR worm gearboxes?
Single-stage gearboxes NBR030–NBR150 cover i = 5, 7.5, 10, 15, 20, 25, 30, 40, 50, 60, 80 and 100. Compound two-stage configurations (e.g. NBR030/063) extend the range to i = 5,000.
Are NBR worm gearboxes self-locking?
Yes – at gear ratios above 20:1 the worm gear is self-locking. This means that when the drive stops, the output shaft cannot be back-driven by the load, without requiring an additional brake. Critical for vertical lifting applications.
Which motors are compatible with NBR gearboxes?
NBR gearboxes mount directly to IEC asynchronous motors via PAM flange B5 or B14. Compatible motor sizes range from frame 56 (NBR030) to 160/180 (NBR150). Nibora offers a full range of SIMOTOP, NBR Drive and Motovario motors.
What is the maximum permissible radial load on the output shaft?
The maximum radial force (Fr2) ranges from 3,490 N for NBR030 to 18,000 N for NBR150. Exact values depend on the gear ratio and motor power – contact us for a specific calculation.
Do you have stock available in Bulgaria?
Yes – Nibora Ltd maintains permanent stock of all 9 sizes (NBR030–NBR150) with over 2,960 units at our warehouse in Pleven. Delivery within Bulgaria is within 24–48 hours.
How do I order an NBR worm gearbox?
Send your enquiry to nibora@nibora.com or call +359 64 681 058. Please specify the size (e.g. NBR063), gear ratio, mounting configuration (FA/FB/FC...) and motor frame size (PAM80 B5 etc.). You will receive a quote within 2–4 hours.