Universal Joint

In this Article, we will learn about What is Universal Joint ? It’s Application Advantage, Disadvantage and It’s working with Figure.

what is universal joint ?

A Universal Joint is a mechanical device which is used to joint or coupling the connecting rigid shafts whose axes are inclined to each other.

Note : It is also called U-joint or a Universal Coupling.

A universal-joint, or U-joint, is a mechanical device used to connect two rotating shafts at an angle. It offers flexibility by accommodating misalignment and compensating for axial and radial movements. Universal joints efficiently transmit torque and rotational power, but they can introduce backlash, vibration, and noise. Despite these limitations, they are widely used in various industries for their versatility, cost-effectiveness, and ability to transmit power between non-aligned shafts.

Must Read : Knuckle Joint

universal joint cross or coupler

A universal joint coupler, also known as a U-joint coupler or universal joint cross. Function of UJ Cross is to maintain uniform motion between the rotating shafts by coupling the stiff metal rods and allowing shaft to move flexibly in angular directions.

universal joint diagram

parts of universal joint

It is composed of several key parts that work together to enable its function effectively. The main parts of a universal joint include:

These parts work together to allow the universal-joint to accommodate misalignment, transmit torque, and enable angular motion between the driving and driven shafts.

how does universal universal joint works

It consists of a cross-shaped component with bearings at the end of each arm.

When one shaft, referred to as the input shaft, rotates, it causes the cross-shaped component to rotate as well. As the component rotates, the bearings allow it to pivot and accommodate the misalignment between the input shaft and the output shaft.

The rotational motion from the input shaft is transferred to the output shaft through the cross-shaped component and the bearings. As a result, the output shaft rotates at a different angle or orientation than the input shaft.

The design of the universal joint allows it to compensate for angular misalignment between the shafts and also absorb small amounts of axial and radial movements. This flexibility enables the universal-joint to maintain a constant velocity ratio between the input and output shafts, even when they are not aligned in a straight line.

By utilising this mechanism, universal-joints are able to transmit power and torque between non-aligned shafts, making them suitable for applications where flexibility and efficient power transmission are required.

working of Universal joint in automobile with figure

The universal joint, depicted in the diagram above, comprises a driving yoke ‘1’ connected to the gearbox’s main shaft, while a driven yoke ‘3’ is connected to the propeller shaft.

These two yokes are linked through a crossed spider ‘2’, which possesses four arms referred to as trunnions. As the driving shaft rotates, it imparts rotation to the driven shaft while allowing for angular motion. Consequently, power is transmitted from the gearbox to the propeller shaft at an inclined angle.

In essence, these joints serve to establish a flexible connection between two rigid shafts positioned at an angle to each other. They facilitate the transmission of power not only at an angle but also during the continuous variation of this angle.

why does universal joint required in propeller shaft

When a vehicle travels on an uneven road, the differential experiences fluctuations in its position, causing the propeller shaft to also adjust its angle as it rotates.

In such situations, universal joints play a crucial role by enabling the propeller shaft to accommodate these angle changes without interrupting the transmission.

If the differential were directly connected to the gearbox without a universal joint, the connection would fail during the movement of the rear axle. This is because without a universal joint, the system lacks the necessary flexibility to handle the adjustments caused by the uneven road surface.

Universal Joint types

(a)Cross or spider joint (variable velocity joint).

(b) Ball and trunnion joint (variable velocity joint).

(c) Constant velocity joints.

A. Cross or spider joint

The universal joint is composed of two Y-shaped yokes and a crosspiece, commonly referred to as the spider. One yoke is connected to the driving shaft, while the other is connected to the driven shaft.

The crosspiece features four arms, known as trunnions, which are attached to the ends of the yokes. Each arm of the crosspiece is equipped with a needle bearing, allowing the yoke to pivot around the trunnion when the driving and driven shafts rotate together at an angle.

b. ball or trunnion joint

A ball trunnion joint is a unique assembly that combines both universal and slip joints. It consists of a ball-type head securely attached to one end of the propeller or drive shaft.

The assembly includes a pin or cross shaft that is pressed through the shaft end, creating a ‘T’ shape. Within this pin, two steel balls are firmly fitted. This joint enables rotational motion through the interaction of the balls and the pin, allowing for smooth movement. Additionally, the balls have the capability to move axially in a specific direction. It’s important to note that ball and trunnion joints also function as variable velocity joints.

c. Constant velocity joints

A Constant Velocity Joint (CV joint) is a specific type of universal joint that enables both the driving and driven shafts to maintain a constant velocity. This is achieved by positioning the two joints at the same angle.

CV joints are commonly utilised in front-wheel drive vehicles, where maintaining a consistent speed between the driving and driven shafts is crucial. Without the use of CV joints, the speed variation between these shafts would pose challenges to the steering system and lead to excessive tire wear.

a universal joint is used to transmit

universal joint is used to connect two shaft whose axes are inclined to each other.

application of universal joint ?

Universal joints have a wide range of applications across different industries and fields. Some of the key applications of universal joints include:

These are just a few examples of the diverse applications of universal joints. Their ability to accommodate misalignment and transmit power between non-aligned shafts makes them invaluable in many industries, where flexibility and efficient power transmission are required.

advantages of universal joint

Universal joints offer several advantages that make them widely used in various applications. Some of the key advantages of universal joints include:

While universal joints offer numerous advantages, it’s important to consider their limitations as well. They can introduce some backlash, vibration, and noise due to their design, and they may not be suitable for applications that require constant velocity or very precise motion control. In such cases, alternative mechanisms like constant velocity joints (CV joints) or flexible couplings may be more appropriate.

disadvantages of universal joint

Disadvantages of universal joints:

It’s important to note that while universal-joints have these disadvantages, they are still widely used in many applications due to their flexibility, cost-effectiveness, and ability to accommodate misalignment. However, in certain specialised applications where precision, high speeds, or low noise levels are critical, alternative mechanisms may be preferred.

Source : Wikipedia

Leave a Reply

Your email address will not be published. Required fields are marked *