カテゴリー: 鉱業

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 ウォームギアボックス 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.

業界における応用例とユースケース

In a typical belt conveyor drive arrangement, the ウォームギアボックス 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.

技術仕様および選定ガイド

以下の表を使用して、適切なモデルを特定してください。主なパラメータには、減速比、出力トルク、シャフト寸法、ハウジング材質が含まれます。常に正しいものを適用してください。 サービス係数（SF） 使用サイクルに合わせて。

パラメータ	標準範囲／値	選考ノート
比率	5:1 – 100:1 (single-stage)	Two-stage tandem available up to 3,600:1
出力トルク	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
ハウジング材	Aluminium alloy / Ductile iron GGG40	Stainless steel 316 available on request
Mounting Type	Foot / Flange / Shaft-mounted	All standard orientations F1–F8
保護等級	IP65 standard; IP66 / IP69K optional	Specify at order for outdoor / washdown duty

► サービス係数（SF）： 均一荷重SF=1.0 | 中程度の衝撃SF=1.25～1.5 | 重度の衝撃／24時間連続SF=1.75～2.0

► 周囲温度： 標準ユニットの動作温度範囲は-10℃～+40℃です。オーストラリアの高温環境（45℃以上）で使用する場合は、高温用潤滑剤と15%規格に基づく熱定格低減が必要です。

NMRV / NRVシリーズウォームギアボックス

フレームサイズは025～150までご用意。単段減速比は5:1～100:1。出力トルクは最大4,200 N·m。ハウジングはアルミニウムまたはダクタイル鋳鉄製。モーターフランジはIEC B5/B14規格。IP65標準、IP66/IP67オプション。潤滑油は合成油または鉱物油。

コンプライアンスおよび品質基準

✓ ISO 9001:2015
品質マネジメントシステム認証取得済み。すべての製品は、文書化された品質マネジメントシステムに基づき、完全なトレーサビリティを確保した上で製造および検査されています。

✓ CE認証
EU機械指令に準拠したCEマーク付き。オーストラリアおよびニュージーランドのエンジニアリングプロジェクトで広く採用されています。

✓ IEC 60034 モーターインターフェース
IEC規格のフランジおよびシャフト寸法。 主要モーターメーカー全社と直接取り付け可能。

✓ IP65 / IP66 保護等級
防塵性と高圧噴射水への耐性を備えています。オーストラリアの屋外設置における標準規格です。

事例研究

⛏️

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

鉱業
Inclined Belt Conveyor

顧客の課題： 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.

解決： 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.

結果： 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.

🏭

Case Study 2 — Mineral Processing Plant, Western Australia

鉱業
Horizontal Ore Conveyor

顧客の課題： 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.

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

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

🌾

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

Bulk Handling
Belt Weigh Feeder

顧客の課題： A grain terminal’s weigh feeder was overspeeding by up to 8%, causing inaccurate throughput measurement and regulatory compliance issues.

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

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

NMRV / NRVシリーズウォームギアボックス - フレームサイズ025～150、ISO 9001:2015規格に準拠して製造

当社を選ぶ理由とは？

🏭

20年以上の製造実績
2003年よりISO認証取得済みの生産体制。ウォームギアボックスは60カ国以上に出荷されています。

📞

リモートテクニカルサポート
オーストラリアのタイムゾーンをまたいだビデオ通話による診断。現地訪問なしで迅速な対応が可能。

⚙️

OEM/ODMカスタマイズ
非標準シャフト、中空ボア、特注フランジ、各種比率に対応可能です。図面レビューも承ります。

💰

工場直販価格
販売代理店のマージンは一切ありません。透明性の高いボリュームディスカウントで、リピート注文で大幅な割引が受けられます。

📦

在庫あり＆迅速発送
標準的なNMRV/NRVフレームは倉庫に在庫がございます。緊急のご注文は速達便にて対応いたします。

よくある質問

▼ 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 engineering team 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.