𝟔 𝓟𝓸𝓲𝓷𝓽𝓼 𝓨𝓸𝓾 𝓢𝓱𝓸𝓾𝓵𝓭 𝓚𝓷𝓸𝔀 𝓑𝓮𝓯𝓸𝓻𝓮 𝓢𝓮𝓵𝓮𝓬𝓽𝓲𝓷𝓰 𝓐 𝓒𝓪𝓻𝓭𝓪𝓷 𝓢𝓱𝓪𝓯𝓽

The cardan shaft is a versatile component in power transmission systems. Its primary feature is the ability to connect two drives that are not on the same axis, reliably transmitting torque and motion. This coupling is known for its high load-bearing capacity, long lifespan, smooth operation, noise-free performance, large axial compensation, and easy maintenance.

Before selecting a cardan shaft, it is essential to clarify certain prerequisites and considerations:

1. Transmission Devices Between the Prime Mover and Cardan Shaft

Determine if there are transmission devices between the prime mover and the universal joint shaft. If present, understand the transmission ratio and the number of output shafts after passing through intermediate transmission devices, consider the type, power, and speed of the prime mover, the magnitude and nature of the torque to be transmitted, and the requirements for buffering and vibration reduction. For example, high-power, heavy-load transmission systems may benefit from gear couplings, while high-speed transmission shafts may require couplings with high balancing precision, such as membrane couplings.

2. Load Categories for Cardan Shaft Selection

Consider the type of prime mover and the load category for transferring loads using the cardan shaft. Determine if it can handle unidirectional constant loads, pulsating loads, or bidirectional alternating loads. Check the installation orientation, ensuring that the axial angle is less than 3 degrees. If inclined installation is unavoidable, determine the horizontal and vertical angles.

3. Operating Environment of the Prime Mover

Evaluate the working environment of the prime mover, including factors such as high temperature, dust, water exposure, chemical corrosion, etc. Choose a corresponding type of cardan shaft based on different usage conditions. Generally speaking, couplings made of non-lubricated metal components are more reliable, while lubricated couplings may be influenced by lubrication levels and could potentially contaminate the environment.

4. Connection Requirements and Installation Dimensions

Understand the connection forms required at both ends of the universal joint shaft and specific installation dimensions, such as the holes, the key, and the shaft sleeves. Also, be aware of any special requirements, such as the need for installation brackets.

5. Shaft Speed and Dynamic Balancing

Determine the rotational speed of the cross-coupling universal joint shaft and assess whether dynamic balancing is necessary. Specify the required level of balance quality. For example, shaft speeds are typically around 1000 RPM for some paper machines, and a balance grade of G16 is commonly chosen.   

6. Installation Constraints and Length

Consider whether there are limitations on the installation position and determine the specific installation length. Assess the need for scalability. If scalability is required, understand the elongation when the cardan shaft is in a shortened state. For non-scalable cardan shafts, compensate for axial dimension errors and determine the compensation position within the system.

By understanding the aforementioned prerequisites, gradually determine the specifications of the cardan shaft and then choose the appropriate structural form. Common structural forms include cross-coupling, ball-cage, ball-fork, convex-block, ball-pin, ball-hinge, ball-hinge-plunger, triple-pin, triple-fork, triple-ball-pin, and hinge-rod. The cross-coupling and ball-cage are commonly used, and in practical applications, they are categorized as heavy-duty, medium-duty, light-duty, and small-duty based on the transmitted torque. Choosing the right universal joint shaft for the prime mover requires a profound understanding of the mentioned prerequisites and external influencing factors.