Universal Coupling Explained

A universal coupling makes use of its mechanism to connect two shafts that are not aligned on the same axis.

Universal Coupling

The universal coupling enables the continuous rotation of the coupled shafts at an angle, allowing for the reliable transmission of torque and motion.

This type of coupling is notable for its large angular compensation ability, compact design, and high transmission efficiency. The angle between the two axes of different structural types of universal joints typically ranges from 5° to 45°.

The structure types

Universal couplings come in various structural types, including:

  • Cross shaft type
  • Ball cage type
  • Ball fork type
  • Bump type
  • Ball type
  • Ball hinge type
  • Ball hinged plunger type
  • Three-pin type
  • Trigeminal type
  • Tripod type
  • Hinge type

The cross shaft type is the most widely used, followed by the ball cage type.

In practical applications, universal couplings are classified into heavy, medium, light, and small types based on the magnitude of the transmitted torque.


There are many types of couplings, and they can be divided based on the change in the relative position and orientation of the two connected shafts.

① Fixed coupling: These couplings are mainly used in applications where strict alignment between the two shafts is required and no relative displacement occurs during operation. They have a simple structure, are easy to manufacture, and the speeds of the two shafts are the same at all times. The most common types of fixed couplings include flange couplings, sleeve couplings, and cage couplings.

② Movable Coupling

Movable couplings are mainly used to accommodate the deflection of two axes or relative displacement in a working setup.

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Based on the compensation method for displacement, movable couplings can be further categorized into rigid and elastic types.

Rigid movable couplings compensate for displacement through the movable joint formed between the working parts of the coupling, in a specific direction or multiple directions of motion. Examples of rigid movable couplings include dental couplings (which allow for axial displacement), cross groove couplings (for connecting two shafts with parallel or angular displacement), universal joints (for accommodating large deflection angles of two shafts or large angular displacement during operation), gear couplings (allowing for integrated displacement), and chain couplings (allowing for radial displacement).

The elastic movable coupling, also known as an elastic coupling, utilizes the elastic deformation of an elastic element to compensate for the deflection and displacement of two shafts.

Additionally, the elastic element provides cushioning and damping properties, such as in the case of serpentine spring couplings, radial multi-layer leaf spring couplings, elastic ring bolt couplings, nylon bolt couplings, and rubber sleeve couplings.

Some of these couplings have been standardized.

When selecting an elastic movable coupling, it is important to follow these steps: First, choose the appropriate type based on your work requirements. Then, calculate the torque and speed based on the shaft diameter. Next, find the applicable model from the relevant manual. Finally, perform necessary checks for key parts.

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