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  • November 08, 2026

Hard toothed cylindrical gear reducer: types, 9 assembly forms

H1: The Ultimate Guide to Hard Tooth Surface Cylindrical Gear Reducers (ZDY, ZLY, ZSY, ZXY)

Choosing the appropriate gearbox architecture is crucial for reliability and space efficiency when designing heavy-duty industrial drive systems. This guide provides a detailed breakdown of the hard toothed cylindrical gear reducer series, covering basic configurations, hollow shaft options, 9 standard assembly types, and complete model code decoding logic.

Tooth Surface Cylindrical Reducer

H2: 1. Basic Types and Hollow Shaft Configurations

The series is categorized by the number of gear stages, offering immense flexibility for various torque and speed requirements.

Tooth Surface Cylindrical Reducer Basic Configurations (Solid Shaft)

  • ZDY Type: Single-stage reducer. Ideal for low reduction ratios.

  • ZLY Type: Two-stage reducer. The industry workhorse for medium to heavy loads.

  • ZSY Type: Three-stage reducer. Designed for higher ratios and massive torque.

  • ZXY Type: Four-stage reducer (Note: specific applications only).

Hollow Shaft Types (The "A" Series)

For applications requiring a more compact footprint or direct mounting onto the driven machine's shaft, hollow shaft variants are available.

  • ZLYA Type: Two-stage hollow shaft reducer.

  • ZSYA Type: Three-stage hollow shaft reducer.

  • ZXYAZ Type: Four-stage hollow shaft reducer.

By eliminating the need for a flexible coupling, the ZLYA hollow shaft gearbox saves critical installation space and reduces alignment errors.

H2: 2. Assembly Configurations: 9 Standard Mounting Types

Flexibility in plant layout is one of the biggest advantages of this series. As shown in the manual, the gearboxes (ZDY, ZLY, ZSY) offer nine distinct assembly configurations (Types I through IX).

These configurations dictate the physical orientation of the input shaft relative to the output shaft.

  • Types I – III: Typically feature horizontal mounting with specific left/right input and output shaft extensions.

  • Types IV – VI: Variations designed to accommodate different coupling alignments.

  • Types VII – IX: Vertical or specialized angular arrangements.

Engineering Tip: When ordering, the assembly type directly affects the internal oil routing and bearing lubrication. Therefore, the mounting position (I-IX) must be specified at the time of purchase.

H2: Need Help Selecting the Right Configuration?

Navigating through the 9 assembly types and matching them to your layout can be complex. Whether you need a standard ZLY two-stage reducer or a specialized ZLYA hollow shaft unit with forced lubrication, we are here to help.

Send us your application details:

  1. Motor power (kW) and Input speed (r/min)

  2. Required ratio or output speed

  3. Mounting orientation / Assembly Type (I-IX)

  4. Required shaft type (Solid or Hollow)



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