Cylindrical Reducer

ZLYJ Series Plastic Extruder Gearbox Reducer

The ZLYJ Series Plastic Extruder Gearbox Reducer is a high-precision, high-torque parallel-shaft gearbox specifically engineered for single-screw plastic extruders used in film blowing, pipe extrusion, sheet production, pelletizing, and compounding lines.

Mounted directly between the motor and the extruder screw, this gearbox transmits power while amplifying torque to drive the rotating screw under high backpressure—often exceeding 30 MPa. Designed for continuous 24/7 operation at elevated temperatures, the ZLYJ series delivers exceptional rigidity, thermal stability, and long-term reliability even under extreme load conditions.

product Information

Key advantages include

High power density with compact footprint

Precision-ground hardened gears for low noise and minimal wear

Integrated thrust bearing system to handle axial screw forces

Multiple cooling options for optimal thermal management

Customizable output shafts compatible with global extruder standards

By ensuring stable screw rotation and consistent melt pressure, the ZLYJ gearbox plays a pivotal role in achieving uniform product quality, energy efficiency, and extended machine uptime.

Product Advantages

Integrated Heavy-Duty Thrust Bearing

Utilizing precision-ground gears and optimized tooth profile design, the transmission backlash is ensured to be ≤1 arcmin, meeting the stringent requirements of servo systems for positioning accuracy and repeatability.

High-Precision Ground Gears

Gears made from high-purity alloy steel (e.g., 18CrNiMo7-6), carburized, quenched, and precision ground to ISO Class 6 accuracy—ensuring smooth meshing, low vibration, and >100,000 hours service life.

Robust Housing with High Rigidity

One-piece ductile iron (QT600-3) or welded steel housing provides excellent torsional stiffness, minimizing deflection under peak loads and maintaining gear alignment.

Low Noise & Vibration

Optimized gear tooth profile and precision assembly keep operational noise below 75 dB(A)—ideal for modern factory environments with strict acoustic requirements.

Multiple Output Shaft Configurations

Available with hollow output shaft (with keyway or spline) to directly connect to the extruder screw, compatible with standard screw designs from Clextral, Leistritz, Berlyn, and domestic manufacturers.

Flexible Cooling & Lubrication Options

Supports natural cooling, forced oil circulation, or oil-water heat exchange systems (see Section 7), enabling stable operation even at high torque and ambient temperatures.

product Information

Working Principle

The ZLYJ gearbox operates as a two-stage or three-stage hardened parallel-shaft reducer:

Input Stage: The motor drives the high-speed input shaft, which connects to the first-stage pinion gear.

Intermediate Stage(s): Power is transferred through one or two intermediate gear sets, progressively reducing speed and increasing torque.

Output Stage: The final gear drives the hollow output shaft, which is directly coupled to the extruder screw.

Critically, the thrust bearing assembly—located inside the output housing—absorbs the massive axial force generated by molten plastic pressure pushing back against the screw. This integrated design ensures that gear teeth only transmit torque, not axial loads, dramatically improving reliability.

Lubrication is typically via oil bath or forced circulation, with oil splashed or pumped onto gear meshes and bearings to dissipate heat and reduce wear.

Product Application

The ZLYJ Series is widely used in a variety of plastic processing equipment, including

Pelletizing & Stranding Lines
Sheet & Plate Production Lines
Cable Sheathing & Coating Machines
Film Blowing Lines (shopping bags, agricultural films)
Single-Screw Extruders for PE, PP, PVC, PET, ABS, and engineering plastics
Pipe & Profile Extrusion Systems (water pipes, window frames)
Recycling & Compounding Extruders (with fillers, glass fiber, masterbatch)
Suitable for both new machine builds and retrofit replacements in brands such as CMT, Battenfeld, Kautex, and Chinese OEMs.

How to Select the Right Model

To choose the correct ZLYJ gearbox, please provide the following details:

Extruder screw diameter (e.g., Φ65 mm, Φ90 mm, Φ120 mm)

Screw L/D ratio (e.g., 30:1, 34:1)

Maximum operating torque or motor power & speed

Material type (e.g., HDPE, filled PP, recycled PET – affects backpressure)

Output shaft interface (hollow shaft ID, keyway size, spline standard)

Cooling preference (natural, oil pump, oil cooler – see Section 7)

Installation space constraints (horizontal/vertical mounting, center height)

Model	ZLYJ112	ZLYJ133	ZLYJ146	ZLYJ173	ZLYJ200	ZLYJ225	ZLYJ250
Thrust KN	41	54	60	153	187	250	268
Model	ZLYJ280	ZLYJ315	ZLYJ330	ZLYJ375	ZLYJ420	ZLYJ450
Thrust KN	356	403	448	495	545	590

Model	ZLYJ112	ZLYJ133	ZLYJ146	ZLYJ173	ZLYJ200	ZLYJ225	ZLYJ250	ZLYJ280	ZLYJ315	ZLYJ330	ZLYJ375	ZLYJ420	ZLYJ450
Ratio	8	8	10	10	12.5	12.5	16	16	16	16	16	16	16
Screw diameter	35	45.5	55	65	75	90	100	105.110	120	130.150	150.160	165	165
Motor power	5.5-4P	7.5-4P	11-4P	18.5-4P	25-4P	45-4P	45-4P	55-6P	75-6P	132-6P	132-6P	160-6P	200-6P
Input speed	800	800	900	900	1000	1000	1120	960	960	960	960	960	960
Output speed	100	100	90	90	80	80	70	60	60	60	60	60	60
Remarks	Motor and reducer are driven by pulley							The motor and reducer are connected by coupling

Assembling Way

Our engineers can perform torque verification, thermal analysis, and provide 3D CAD models (STEP/IGES) to ensure perfect integration.

Cooling Methods

To maintain optimal oil temperature (<80°C) and prevent lubricant degradation under continuous high-load operation, the ZLYJ series supports three cooling configurations:

● Natural Air Cooling (Standard for Small Models)

Suitable for low-to-medium power extruders (<150 kW)

Heat dissipation through ribbed housing surface

Simple, cost-effective, no auxiliary components

● Forced Oil Circulation (Oil Pump Cooling)

Integrated gear pump circulates oil through internal channels

Enhances lubrication to bearings and gear meshes

Recommended for medium-duty applications (150–300 kW)

● Oil Pump + Oil Cooler (For Heavy-Duty & High-Torque Use)

Combines forced circulation with an external oil-to-water or oil-to-air heat exchanger

Maintains stable oil temperature even in high-ambient or high-backpressure conditions

Ideal for large extruders (>300 kW), recycling lines, or 24/7 industrial operations