Allpa Flexible Rubber Propeller Shaft Coupling with Metal Inserts – 140–200 Nm

Allpa Flexible Rubber Propeller Shaft Coupling with Metal Inserts – 140–200 Nm

The Allpa Flexible Rubber Propeller Shaft Coupling is a marine coupling component featuring a flexible rubber body with metal inserts. It is designed for inboard marine propulsion shaft connections and is available in two torque ratings: 140 Nm and 200 Nm.

The coupling provides a flexible connection between compatible coupling flanges in a marine propulsion system. Both versions have model-specific mounting dimensions and a specified maximum rotational speed of 2,000 rpm.

Coupling selection is based on the transmitted torque and the application factors specified for pleasure boats, commercial vessels and different engine cylinder configurations.

Key Features

• Flexible rubber construction: Coupling body with metal inserts.
• Two torque ratings: Available in 140 Nm and 200 Nm versions.
• Inboard application: Intended for marine propulsion shaft connections.
• Maximum rotational speed: 2,000 rpm.
• Mounting pitch dimension: 82.5 mm specified for both models.
• Model-specific dimensions: Different axial and flange dimensions for each configuration.
• Application-based torque selection: Selection factors specified for pleasure and commercial vessels.
• Engine configuration factor: Separate factors for engines with four cylinders or fewer and engines with more than four cylinders.

Technical Specifications

Available Models and Dimensions

The following dimensions correspond to the designations shown in the technical drawings. Linear dimensions are expressed in millimetres.

Flexible Rubber Coupling Construction

The coupling features a flexible rubber body with metal inserts incorporated into the mounting arrangement.

Its design provides a flexible mechanical connection within the marine propulsion shaft assembly. The selected coupling must match the required transmitted torque and the dimensions of the mating flanges.

Torque Ratings and Selection Formula

The two available couplings have specified torque ratings of 140 Nm and 200 Nm.

The coupling selection formula is:

Mt = Mtm × Ks × Kc

• Mt: Required coupling torque rating in Nm.
• Mtm: Engine torque in Nm.
• Ks: Vessel application factor.
• Kc: Engine cylinder configuration factor.

The calculated required torque rating should be used to select an appropriately rated coupling.

Application Selection Factors

Maximum Rotational Speed

The maximum specified rotational speed for the flexible rubber coupling range is 2,000 rpm.

The coupling must be selected with consideration of the operating rotational speed and transmitted torque of the propulsion shaft system.

Mounting Dimensions

The 140 Nm and 200 Nm couplings have different mounting dimensions. Both versions have a specified dimension A of 82.5 mm, while dimension B is 108 mm for article 9001140 and 120 mm for article 9002200.

Additional dimensions C, D, E and F are specified for each model. Dimensions G and H are additionally provided for article 9001140.

Verify the dimensional drawing and mating flange arrangement before installation.

Propeller Shaft Torque Calculation

Propeller shaft torque can be calculated from engine power, engine rotational speed and gearbox reduction ratio using the following relationship:

Shaft Torque (Nm) = [Engine Power (kW) / Engine Speed (rpm)] × 9680 × Gearbox Reduction Ratio

An alternative relationship using metric horsepower is:

Shaft Torque (kgm) = [Engine Power (PS) / Engine Speed (rpm)] × 726 × Gearbox Reduction Ratio

Conversion factors:

• 1 kgm = 9.807 Nm
• 1 PS = 0.736 kW
• 1 kgf = 9.807 N
• 1 kN = 1,000 N

Selection and Compatibility

Select the appropriate Allpa flexible rubber coupling according to the calculated torque requirement, maximum rotational speed and mounting dimensions.

• 9001140: 140 Nm torque rating, dimension A 82.5 mm and dimension B 108 mm.
• 9002200: 200 Nm torque rating, dimension A 82.5 mm and dimension B 120 mm.

Before ordering, verify the required torque rating, mating flange dimensions, mounting hole arrangement and operating speed of the propulsion system.