1. Overview

Industrial NM Flexible Rubber Couplings (Cast Iron Jaw Couplings)

Reliable Shock-Absorbing Shaft Couplings for Water Pumps & Heavy Industrial Drive Systems

Apex Coupling’s NM Flexible Rubber Couplings feature high-grade cast iron hubs (precision cast according to GB9439 standards) and a high-wear natural/NBR rubber spider element. Engineered for exceptional vibration dampening and torsional flexibility, NM couplings protect connected equipment from shock loads while compensating for axial, radial, and angular shaft misalignments.

• Hub Material: Premium Cast Iron (Precision Cast)

• Buffer Element: Wear-Resistant Rubber Spider

• Bore Precision: H7 Bore Tolerance

• Applicable Shaft Diameter: 7 mm – 75 mm

• Applicable Motor Power: Up to 45 kW (60 HP)

• Max Torque Capacity: Up to 125 kg·m (1,225 N·m)

• Custom Bores Supported: Keyway (K), Hexagon (F), Square (S), Spline (H)

• MOQ: 1 PCS (Fast production for bulk wholesale orders)

Request B2B Wholesale Quote ]  Download NM Coupling Specs (PDF) ]

2. Key Features & Industrial Advantages

Why Choose Apex NM Flexible Rubber Couplings?

1. High-Precision H7 Bore Fitting: Precision-machined H7 tolerance inner bores ensure exact shaft alignment, reducing runout, maximizing power transfer efficiency, and preventing premature shaft wear.

2. Superior Shock & Vibration Dampening: The flexible rubber insert acts as a cushion, absorbing shock loads and dampening system vibrations to safeguard motor bearings, pumps, and gearboxes.

3. High Strength Cast Iron Hubs: Manufactured with quality cast iron and advanced precision casting processes, preventing hub fracturing under high-torque starting loads.

4. Simple Structure & Easy Installation: Consists of only two cast iron jaw hubs and one flexible rubber ring. Quick to install, align, and maintain without moving connected machinery.

5. Corrosion & Wear Resistance: Finished with industrial protective spray painting (custom coatings available) to resist corrosion, moisture, and mild chemicals in tough pumping environments.

3. Technical Specifications & Dimension Chart

Technical Parameters & Model Selection Guide

Model Naming & Custom Bore Options

• Model Example:  NM50-50×51.5-7×7 (Outer Diameter D = 50 mm, Length L =
  51.5 mm, Bore d1 = 7 mm, Bore d2 = 7 mm)

• Custom Hole Coding:

  • Keyway Bore: Add suffix K (e.g. 7K)

  • Hexagonal Hole: Add suffix F

  • Square Hole: Add suffix S

  • Splined Bore: Add suffix H

(Need special bore dimensions, custom keyways, or specific rubber hardness? Contact our engineering support.)

4. Target Industrial Applications

Wide Range of Industrial Applications

Apex NM flexible rubber couplings are designed for continuous duty across demanding industries:

• Water Pump & Centrifugal Pump Connections

• CNC Machine Tools & Woodworking Machinery

• Packaging, Food Processing & Printing Equipment

• Metallurgy, Chemical & Mining Conveyor Systems

• Photovoltaic Power & Semiconductor Manufacturing Gear

• Railway Track & Heavy Drive Machinery

5. B2B Inquiry Form

Get a Fast Factory Quote for NM Couplings

Looking for a trusted manufacturer for bulk NM couplings, custom bore machining, or OEM replacement parts? Submit your technical requirements below.

• Company / Contact Name:

• Business Email (Work Email Preferred):

• Target NM Model / Shaft Diameter (d1/d2)：

• Custom Requirements (Keyway size, Set screws, Rubber material):

• Estimated Order Quantity (PCS / Sets):

• Upload Shaft/Machine Drawing (Optional):