Medium Hardened Helical Bevel Speed Reducer Three Stage Gearing Gear Reducers Parallel Shaft

QJ Series Medium-Hardened Helical Gear Reducer involute gears three-stage gearing

I. Product Introduction

The QJ series reducer is a medium-hardened, parallel shaft, helical gear reducer. It is specifically designed for hoisting machinery and complies with the Chinese Machinery Industry Standard JB/T 8905.1-1999 (equivalent to the W series reducer from Mannesmann Demag AG, Germany). This series employs involute gears that undergo precision machining processes like quenching and grinding, resulting in high load capacity, long service life, high efficiency, and low noise. Its structure features three-stage gearing and a cast iron housing with excellent rigidity, making it a core transmission component in heavy industries, particularly in material handling and lifting.

II. Main Technical Parameters

1. Model Designation: QJS, QJR, QJS-D, QJR-D, etc. (D denotes models with a cooling coil).

2. Center Distance (mm): Main sizes include: 160, 180, 200, 224, 250, 280, 315, 355, 400, 450, 500, 560, 630, 710, 800.

3. Number of Stages: Three-stage reduction.

4. Ratio Range (i): Nominal ratio range is very wide, typically from 25 to 450, with an even broader practical selection available.

5. Input Power (kW): Covers a vast range, from several kW to over 1000 kW.

6. Output Torque (N·m): Extremely wide range, from several thousand N·m to several million N·m.

7. Permissible Radial Load: High permissible radial load depending on the model, capable of directly withstanding the immense radial force from heavy-duty drums.

8. Gear Accuracy: High gear precision, typically achieving Grade 6 or better per GB/T 10095.1-2008 (comparable to ISO 1328).

9. Gear Material: Gears are made from high-quality alloy steel (e.g., 20CrMnTi, 42CrMo), treated by case carburizing and hardening or surface hardening. Tooth surface hardness reaches HRC 54-62.

10. Efficiency: High single-stage efficiency (>98%), overall efficiency is typically above 95%.

III. Key Advantages & Features

1. High Load Capacity: Medium-hardened tooth surfaces (hard surface, tough core) and gear grinding ensure high strength, precision, and ability to withstand extreme shock loads.

2. High Reliability: Designed specifically for the demanding duty cycles (e.g., S4, S5) of hoisting machinery. Robust construction ensures long operational life.

3. High Transmission Efficiency: Gear grinding provides high meshing accuracy and low friction loss, offering significantly higher efficiency than soft-faced gear reducers.

4. Compact Design, Small Size: Offers a smaller footprint compared to soft-faced reducers with equivalent output torque, saving installation space.

5. Excellent Thermal Performance: Housing is designed with cooling fins. Larger models can be equipped with a cooling coil (D-type) or external cooling system for effective temperature control.

6. Easy Installation & High Adaptability: Input shaft end can accommodate elastic couplings, gear couplings, or connections with a brake drum. The output shaft end features a large cylindrical shaft, facilitating direct connection to the drum and capable of handling high radial loads.

IV. Primary Application Fields

The QJ series reducer is the standard in the lifting industry and is widely used in various equipment for heavy load lifting and movement:

• Overhead Cranes (EOT Cranes): Gantry travel mechanism, crab travel mechanism, hoisting mechanism.

• Gantry Cranes: Hoisting mechanism, gantry travel mechanism.

• Tower Cranes: Hoisting mechanism, slewing mechanism (for some models).

• Port Machinery: Ship-to-shore container cranes (STS), rubber-tyred gantry cranes (RTG), portal slewing cranes.

• Metallurgical Machinery: Charge rod lifting mechanisms for steelmaking furnaces, auxiliary drives for rolling mills.

• Mining Machinery: Mine hoists, drive units for belt conveyors.

• Construction Machinery: Winches, lifting mechanisms for mixing plants.

• Any other heavy industrial applications requiring low-speed, high-torque, and highly reliable transmission.