Z3A Locking Assembly

Z2 Locking Assembly

Overview

The Z3A Locking Assembly is a heavy‑duty, self‑centering keyless shaft‑hub locking device engineered for demanding torque transmission and zero‑backlash operation. Unlike standard Z2 or Z3 designs, the Z3A features a steeper taper angle and longer engagement length, resulting in significantly higher radial clamping force per screw. Tightening the high‑strength 12.9 bolts uniformly expands the inner and outer rings against shaft and hub, creating a reliable friction lock – no keyways, no splines, no shrink fits.

Key Features

High torque density – Up to 30% more torque capacity than standard Z3 in the same outer diameter.

Wide clamping range – Accommodates larger shaft tolerances (h8/h9) without performance loss.

Self‑centering & backlash‑free – Maintains ≤0.02 mm concentricity ideal for precision drives.

Easy assembly – Only a torque wrench needed; no heating, pressing or hydraulics.

Reversible & reusable – Withstands reversing loads and can be reassembled multiple times.

Interchangeable – Direct replacement for TLK130, KLDA, RCK70, LOCK4, and other major Z3A‑style locking assemblies.

Typical Applications

Conveyor drives, belt pulleys, sprockets

Gearboxes, speed reducers, couplings

Packaging machinery, labeling machines

Woodworking equipment, printing presses

Industrial fans, pumps, blowers

Specfications:

Customer satisfaction:

FAQS:

Q1:What is the difference between Z3A and Z3 locking assemblies?
Z3A offers a wider clamping range and higher torque capacity per diameter, thanks to an optimized taper angle and longer axial length. Z3 is more compact for light‑to‑medium duty, while Z3A is preferred for heavy‑duty, high‑shock applications.

Q2:Can the Z3A locking assembly be used in high‑speed applications?
Yes, but above 3000 RPM dynamic balancing is recommended. The self‑centering design maintains concentricity, yet high rotational speeds may require additional balancing verification.

Q3:What surface finish is required on the shaft and hub for Z3A?
Surface roughness Ra ≤ 1.6 µm and a hardness of at least 180 HB are recommended. The contact surfaces must be clean, dry, and free from grease or oil.

Q4:How to calculate the required tightening torque for Z3A screws?
Refer to the torque‑tightening chart provided with each size. As a rule, use the specified torque (Nm) for property class 12.9 screws. Over‑tightening can distort the rings; under‑tightening leads to slippage.

Q5:Is the Z3A locking assembly suitable for reversing loads?
Absolutely. The friction‑locked connection is backlash‑free and withstands frequent forward‑reverse and impact loads without fatigue failure, provided the installation torque is correct.

Q6:What happens if the Z3A locking assembly is overloaded?
It acts as a torque limiter: the device will slip on the shaft or inside the hub, protecting connected machinery from damage. After overloading, disassemble, inspect for scoring, and reassemble with proper torque.

Q7:Does the Z3A locking assembly require any lubrication before installation?
No. The locking screws must be lightly oiled (on threads and under heads) to achieve correct preload, but the tapered ring interfaces and contact surfaces with shaft/hub must remain completely oil‑free to maintain friction.

Robin Cheu

Marketing Manager

sales@shangxincaster.com

Ningbo Shangxin Caster Wheels

No.187, Langxia street, Yuyao city, Ningbo, Zhejiang, China.

Tel. +86 0574-62188162

Whatsapp/Mob. +86 152 5836 8162

Wechat: robin-cheu

www.shangxincaster.com

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