Categories: Perlombongan

Worm Gearbox for Belt Conveyor Systems

Belt conveyors are the circulatory system of Australia’s mining and bulk-materials industry, moving millions of tonnes of coal, iron ore, grain, and mineral aggregate every year. Behind every reliably running conveyor is a precisely selected drive unit — and the kotak gear cacing has earned its dominant position through a combination of self-locking geometry, compact right-angle output, and robust high-torque delivery.

The self-locking characteristic is particularly critical on inclined conveyors: when power is removed, the irreversible worm geometry prevents the loaded belt from reversing under gravity. This eliminates the need for a separate backstop or motorised brake on many installations, simplifying the mechanical design and reducing maintenance exposure.

Standard NMRV and NRV series aluminium or ductile-iron worm gearboxes are available in frames from 025 to 150, providing output torques from 2.6 N·m up to 4,200 N·m and reduction ratios from 5:1 to 100:1 in a single compact stage. Two-stage tandem configurations extend this to 3,600:1.

Aplikasi & Kes Penggunaan Industri

In a typical belt conveyor drive arrangement, the kotak gear cacing sits between the electric motor and the conveyor head drum. Key application points include:

Head-end drive units on horizontal conveyors — steady torque, self-lock on stop
Inclined conveyor drives — self-locking prevents roll-back under loaded belt weight
Take-up winch drives — precise low-speed tension control on counterweight systems
Belt weigh feeder drives — accurate, vibration-free low-speed output

Materials: Worm shaft in surface-hardened alloy steel 20CrMnTi (HRC 58–62). Worm wheel in centrifugally cast phosphor bronze. Housing in ductile iron GGG40 with IP65 dust-and-jet-water sealing.

Working principle: The helical worm thread engages the bronze wheel teeth at 90°. Back-driving from the wheel side is geometrically prevented when the lead angle is below the friction angle — this is the self-locking mechanism at the heart of safe conveyor operation.

Spesifikasi Teknikal & Panduan Pemilihan

Gunakan jadual di bawah untuk mengenal pasti model yang sesuai. Parameter utama termasuk nisbah pengurangan, tork output, dimensi aci dan bahan perumah. Sentiasa gunakan yang betul Faktor Perkhidmatan (SF) untuk kitaran tugas anda.

Parameter	Julat / Nilai Lazim	Nota Pemilihan
Nisbah	5:1 – 100:1 (single-stage)	Two-stage tandem available up to 3,600:1
Tork Output	2.6 – 4,200 N·m	Dependent on frame size 025–150
Input Shaft Diameter	11 – 42 mm	IEC 60034 standard flange sizes B5/B14
Output Shaft Diameter	14 – 50 mm (solid)	Hollow bore available from frame 030 up
Bahan Perumahan	Aluminium alloy / Ductile iron GGG40	Stainless steel 316 available on request
Mounting Type	Foot / Flange / Shaft-mounted	All standard orientations F1–F8
Kelas Perlindungan	IP65 standard; IP66 / IP69K optional	Specify at order for outdoor / washdown duty

► Faktor Perkhidmatan (SF): Beban seragam SF=1.0 | Kejutan sederhana SF=1.25–1.5 | Kejutan berat / 24 jam berterusan SF=1.75–2.0

► Suhu ambien: Unit standard yang dinilai –10°C hingga +40°C. Tapak ambien tinggi Australia (>45°C) memerlukan pelincir suhu tinggi dan penyahterapan haba 15%.

Kotak Gear Cacing Siri NMRV / NRV

Terdapat dalam saiz bingkai 025 hingga 150. Nisbah pengurangan peringkat tunggal 5:1 hingga 100:1. Tork output sehingga 4,200 N·m. Perumah aluminium atau besi mulur. Bebibir motor IEC B5/B14. Piawaian IP65, IP66/IP67 pilihan. Pelinciran minyak sintetik atau mineral.

Piawaian Pematuhan & Kualiti

✓ ISO 9001:2015
Sistem pengurusan kualiti diperakui. Setiap unit yang dikeluarkan dan diperiksa di bawah SPK yang didokumenkan dengan kebolehkesanan penuh.

✓ Pensijilan CE
Ditanda CE untuk Arahan Jentera EU. Diterima secara meluas untuk projek kejuruteraan Australia dan New Zealand.

✓ Antara Muka Motor IEC 60034
Dimensi bebibir dan aci piawai IEC. Keserasian pemasangan terus dengan semua jenama motor utama.

✓ Perlindungan IP65 / IP66
Kedap habuk dan tahan jet-air bertekanan tinggi. Piawaian untuk pemasangan luar Australia.

Kajian Kes

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Case Study 1 — Open-Cut Coal Mine, Hunter Valley NSW

Perlombongan
Inclined Belt Conveyor

Titik Kesakitan Pelanggan: A coal mine was experiencing rollback on a 15° inclined conveyor each time the belt tripped under overload. The mechanical backstop failed twice in six months, causing 18 hours of downtime per incident.

Penyelesaian: NMRV-110 worm gearboxes (ratio 60:1, ductile iron, IP65) were installed on both drive stations. The inherent self-locking eliminated the need for the external backstop entirely.

Keputusan: Zero rollback incidents over 14 months. Annual maintenance cost reduced by 35%. The mine standardised the same model across three further inclined conveyors on site.

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Case Study 2 — Mineral Processing Plant, Western Australia

Perlombongan
Horizontal Ore Conveyor

Titik Kesakitan Pelanggan: A WA iron ore processor needed to replace an ageing helical gearbox generating 74 dB(A) of gear noise, with oil changes every 1,500 hours due to worn lip seals.

Penyelesaian: NRV series worm gearbox (ratio 40:1, 1,800 N·m) with upgraded FKM double-lip seals and synthetic PAO gear oil.

Keputusan: Operating noise reduced to 61 dB(A). Oil change interval extended to 5,000 hours. Zero seal leaks during two 12-month inspection cycles.

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Case Study 3 — Grain Handling Terminal, Port of Geraldton WA

Bulk Handling
Belt Weigh Feeder

Titik Kesakitan Pelanggan: A grain terminal’s weigh feeder was overspeeding by up to 8%, causing inaccurate throughput measurement and regulatory compliance issues.

Penyelesaian: NMRV-063 worm gearboxes (ratio 80:1) replaced the helical-bevel units. Smooth, low-backlash output eliminated speed hunting corrupting the load cell signal.

Keputusan: Throughput accuracy improved to within 0.3% of certified scale. Port authority compliance reinstated within one week.

Kotak gear cacing siri NMRV / NRV — saiz bingkai 025 hingga 150, dikeluarkan mengikut ISO 9001:2015

Mengapa Pilih Kami?

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20+ Tahun Pembuatan
Pengeluaran yang diperakui ISO sejak tahun 2003. Kotak gear cacing dihantar ke lebih 60 buah negara.

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Sokongan Teknikal Jauh
Diagnostik panggilan video merentasi zon waktu Australia. Respons pantas tanpa lawatan di tapak.

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Pengubahsuaian OEM / ODM
Aci bukan standard, lubang berongga, bebibir dan nisbah tersuai. Ulasan lukisan penuh tersedia.

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Nilai Langsung Kilang
Tiada margin pengedar. Penentuan harga volum yang telus dengan penjimatan yang ketara untuk pesanan berulang.

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Stok & Penghantaran Pantas
Bingkai NMRV/NRV standard dalam stok gudang. Pesanan segera diproses untuk penghantaran ekspres.

Soalan Lazim

▼ What is the difference between NMRV and NRV worm gearboxes for conveyor applications?

NMRV units feature an aluminium alloy housing — lighter and suited to lighter-duty or indoor drives. NRV units use cast iron — greater rigidity and thermal mass, preferred for continuous heavy-load mining conveyors. Both share identical internal geometry and are interchangeable in mounting footprint within the same frame size.

▼ How do I calculate the required reduction ratio for my belt conveyor?

Required ratio = Motor RPM ÷ Required drum RPM. Drum RPM = (Belt speed m/s × 60) ÷ (π × drum diameter m). For example, 1.5 m/s belt on a 400 mm drum needs 71.6 RPM. With a 1,400 RPM motor, required ratio is 19.6:1 — select 20:1 or 25:1. Contact our pasukan kejuruteraan for a free calculation.

▼ Does a worm gearbox on an inclined conveyor require a separate anti-rollback device?

For inclinations up to approximately 20° and loads within the rated self-locking torque, worm geometry alone provides sufficient anti-rollback protection. Above 20° inclination or for very high-inertia belt loads, a supplementary backstop or brake is recommended as safety redundancy.

▼ What IP protection rating should I specify for a mine-site belt conveyor gearbox?

IP65 is the minimum for all open mine-site conveyor applications. For conveyors near water sprays, dewatering areas, or underground wet zones, specify IP66 or IP67. Our standard NMRV/NRV range is IP65 as standard, with IP66 and IP67 available as factory options.

▼ What lubricant is recommended for worm gearboxes on mining conveyors in hot Australian climates?

Standard mineral ISO VG 220–460 is suitable for ambient temperatures up to 35°C. For outback sites regularly exceeding 40°C, synthetic PAO ISO VG 320 is recommended — it reduces internal operating temperature by 8–12°C and extends the oil change interval from 2,000 hours to 5,000+ hours.

▼ Can worm gearboxes be used for reversing conveyor applications?

Yes — worm gearboxes can be driven in both directions at the same rated torque. The self-locking feature applies in both directions. For applications requiring free coasting in reverse, a low-lead-angle (non-self-locking) ratio must be specifically selected. Consult our technical team to confirm self-locking status for your chosen ratio.