High Load Capacity Heavy Duty Gear Reduction Box PJ Type High Transmission Efficiency

ZQA (PJ) Series Medium-Hard Gear Reducer high load capacity, high transmission efficiency

1. Introduction

The ZQA series reducer (also known as PJ type) is a very popular medium-to-hard hardened cylindrical gear reducer. It is an upgraded version of the traditional ZQ (JZQ) soft-gear reducer, inheriting its mounting dimensions and interfaces while achieving a qualitative leap in performance and reliability. This series uses alloy steel forged gears that are carburized and quenched, resulting in high tooth surface hardness (HRC 54-62), and are precision ground. Its characteristics include high load capacity, high transmission efficiency, long service life, and strong universality. It is an ideal choice for replacing older ZQ series reducers in many industrial fields.

2. Key Parameters

• Models: Usually denoted by center distance, e.g., ZQA-350, ZQA-400, ZQA-500, ZQA-650, ZQA-750, ZQA-850, ZQA-1000 (the number represents the center distance in millimeters). PJ models correspond, e.g., PJ350.

• Transmission Stages: Double and triple stage reduction.

• Ratio Range (i): Wide range of coverage, common ratios from about 8:1 to 50:1.

• Center Distance (a): Ranges from 250mm to over 1000mm, forming a complete series.

• Input Power: Ranges from tens of kilowatts to hundreds of kilowatts.

• Output Torque: Provides medium to very high output torque to meet various heavy-duty needs.

• Gear Design:

  • Tooth Profile: Involute cylindrical gears.

  • Surface Hardness: Hardened (HRC 54-62), with extremely high surface hardness, excellent wear and pitting resistance.

  • Precision: High gear precision (usually up to Grade 6-7 per GB/T10095), precision ground.

• Mounting Position: Horizontal mounting. Fully compatible with ZQ series mounting dimensions, facilitating equipment upgrades and retrofits.

• Lubrication: Usually splash lubrication.

3. Product Advantages

• Extremely High Load Capacity: The hardened gear design increases its load capacity by 3-5 times compared to soft-gear ZQ series reducers of the same center distance.

• Perfect Interchangeability: Mounting dimensions and interfaces are completely identical to the traditional ZQ (JZQ) series. This allows for direct replacement and upgrade without modifying foundations or connecting parts, significantly improving equipment performance.

• High Transmission Efficiency: Precision ground gears enable transmission efficiency of over 97%, leading to significant energy savings.

• Long Service Life: Excellent wear resistance extends service life by several times compared to soft-gear reducers under the same operating conditions.

• High Reliability: Manufactured with high-quality materials and advanced processes, ensuring stable operation and low failure rates.

• High Cost-Effectiveness: Although the unit cost is higher than that of soft-gear reducers, the significant performance improvement and extended service life result in higher comprehensive economic benefits.

4. Typical Applications

The ZQA (PJ) series is widely used in various equipment requiring heavy-duty, medium-to-low speed transmission. It is the premier choice for technical renovation of old equipment.

• Conveying Equipment: Belt conveyors, apron conveyors, scraper conveyors.

• Lifting Equipment: Travel and hoist mechanisms of overhead cranes and gantry cranes.

• Metallurgy & Mining: Auxiliary drives for rolling mills, wire drawing machines, hoists, feeders.

• Chemical Equipment: Large agitators, kiln drives.

• General Machinery: Any application originally using a ZQ series reducer can be efficiently upgraded with the ZQA series.