NM Flexible Jaw Coupling Cast Iron for Water Pumps & Electric Motors

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NM Series Cast Iron Flexible Rubber Jaw Coupling | Water Pump & Electric Motor Shaft Coupling

Model Number
Check below, custom

NM50-D50-Bore(7~19)-L(51.5~52)
NM67-D67-Bore(8~28)-L(62~62.5)
NM82-D82-Bore(10~32)-L(82~84)
NM97-D97-Bore(12~42)-L(102~104)
NM112-D112-Bore(14~48)-L(122.5~124.5)
NM128-D128-Bore(18~55)-L(142.5~144.5)
NM148-D148-Bore(22~65)-L(162.5~164.5)
NM168-D148-Bore(28~75)-L(174.5~180.5)
NM198-D198-Bore(32~88)-L(202.5~204.5)
NM218-D218-Bore(45~95)-L(222~230)
NM240-D240-Bore(60~110)-L(242~246)

NM265-D265-Bore(70~120)-L(283.5~287.5)

Product Description

NM Series Cast Iron Flexible Jaw Rubber Coupling

Precision Cast Iron Shaft Coupling for Electric Motors & Industrial Water Pumps

The NM Series Flexible Jaw Coupling is engineered for heavy-duty industrial applications, specifically designed to couple electric motors with water pumps, compressors, and fluid machinery. Constructed from precision-cast iron compliant with GB9439 standards and fitted with a resilient natural rubber ring insert, the NM coupling delivers high torque transfer (up to 125 kg·m / 1250 N·m), smooth operation, and exceptional shock absorption.

Key Advantages & Features

Precision Cast Iron Construction: Manufactured using high-grade precision casting techniques compliant with GB9439 standards, preventing premature fracture and ensuring maximum mechanical reliability.
High Torque Capacity: Delivers robust torque transmission with ratings up to 125 kg·m (1250 N·m), ideal for electric motors up to 60 HP / 45 kW.
Natural Rubber Ring Insert: Flexible elastomeric insert absorbs vibration, dampens operational noise, and compensates for minor axial, radial, and angular misalignments.
Smooth & Quiet Operation: Engineered for stable rotational balance and low-noise performance in continuous-duty pumping and industrial systems.
Wide Bore Range & Standardized Models: Supports shaft diameters from 7mm up to 120mm across standard NM model sizes (NM50 to NM265).

Technical Specifications

Parameter	Specification Details
Coupling Series	NM Series Flexible Jaw / Rubber Coupling
Hub Material	Precision Cast Iron (GB9439 Standard Compliant)
Insert Material	High-Durability Natural Rubber Ring
Maximum Torque	Up to 125 kg·m / 1,250 N·m (Range: 230 – 1250 N·m)
Applicable Motor Power	Up to 60 HP / 45 kW
Shaft Bore Capacity Range	7 mm to 120 mm
Max Speed Rating	Up to 5,000 RPM (Rotational range: 0~10,000 RPM)
Fastening Method	Keyway & Setscrew
Certifications	ISO9001 Quality System Certified

Standard Model Sizes (NM Series Specification Chart)

Model designation	Outer Diameter (D)	Bore Range (mm)	Total Length (L)
NM50	50 mm	7 – 19 mm	51.5 – 52 mm
NM67	67 mm	8 – 28 mm	62 – 62.5 mm
NM82	82 mm	10 – 32 mm	82 – 84 mm
NM97	97 mm	12 – 42 mm	102 – 104 mm
NM112	112 mm	14 – 48 mm	122.5 – 124.5 mm
NM128	128 mm	18 – 55 mm	142.5 – 144.5 mm
NM148	148 mm	22 – 65 mm	162.5 – 164.5 mm
NM168	168 mm	28 – 75 mm	174.5 – 180.5 mm
NM198	198 mm	32 – 88 mm	202.5 – 204.5 mm
NM218	218 mm	45 – 95 mm	222 – 230 mm
NM240	240 mm	60 – 110 mm	242 – 246 mm
NM265	265 mm	70 – 120 mm	283.5 – 287.5 mm

Applications & Industries Served

The NM cast iron rubber coupling is an industry workhorse widely used in heavy industrial and fluid handling machinery:

Pumping Systems: Centrifugal water pumps, industrial chemical pumps, sewage pumps, and agricultural irrigation pumps.
Electric Motors & Power Drives: Standard AC electric motors, gearboxes, and generators.
Industrial Equipment: Food processing machinery, construction works, mining equipment, printing machinery, and heavy manufacturing plant machinery.

Custom & OEM/ODM Manufacturing (Non-Standard Bore & Keyway Options)

At ApexCoupling, we offer custom machining for non-standard shaft bores, special keyway dimensions, spline fits, and custom hub lengths to suit your specific pump or motor installation requirements.