How Does a Constant Velocity Joint Work

How Does a Constant Velocity Joint Work: Should know a car owner

Ever wondered how easily your car wheels are turning at variable angles with only one power source inside? That’s the magic a CV joint spells! Every vehicle has CV joints that work in the same manner, whether it’s a front-wheel-drive or rear-wheel-drive vehicle.

A CV joint gives your car the flexibility it needs to move and ensure proper transmission of power without sacrificing the rotation and speed. So how does a constant velocity joint work? We are about to find it out in this article!

Stay tuned to explore!

What Are Constant Velocity Joint (CV Joints)? 

CV Joint

Constant Velocity joints or CV joints are something that assists the driveshaft to carry on its task. These joints are attached to the two different ends of the driveshaft.

These joints work perfectly well to transmit the power from the transmitter to the wheels of the vehicle.

There are basically two joints that are attached to any driveshaft. If you are not well-versed in CV joints and all, both of them will look extremely identical, and you may confuse one with the other.

But the reality is, the two joints are meant to be attached to two different places. Basically, these two joints are referred to as outboard and inboard joints. The outboard ones are connected to the car wheels’ hub assembly. This joint doesn’t move that much except for a bit of twisting.

On the other hand, the inboard joint is connected to the transmission of the vehicle to channel the power from it. The outboard is generally referred to as a fixed joint for its lesser mobility, while the inboard is known as and sliding joint for its sliding nature.

What Do Exactly These CV Joints do?

How Does a Constant Velocity Joint Work? Now, you have got a rough idea of why these joints are in your car; it’s time you go a bit deeper on what do these joints do. There are generally three things that car joints do.

  • Develops the motion of the car wheels
  • Transfers power to the wheels.
  • Rotates the vehicle wheels at a constant speed

It develops the motion of the car wheels

If your car wheels are attached to a rigid shaft, it will force the wheels to move with the suspension of your vehicle. So if you are driving your car on a bumpy road, the shaft will cause the entire car to bump upwards and downwards.

If that’s not the case, the shaft may even get detached from the wheels, causing the wheels to drift away from the car itself.

Using an outboard CV joint makes sure that the car wheels have a wide range of motion to make sure it moves quite fast and smoothly on different roads.

Transfers power from the transmission to the wheels

As for the inboard CV joints, these joints contain some good round-shaped ball bearings. These bearing can move and rotate without causing any friction, which allows it to drag power from the transmission and channel it to the wheels.

It causes very low heat loss, making it possible to transfer almost all the power produced from the transmission.

Rotates the vehicle wheels at a constant speed 

Both the inboard and outboard CV joints will rotate and move at a universal speed. This means the wheels will also move without any hamper. This ensures that the wheels will constantly move no matter at what angle the joints are turning.

So in any of these regular operations gets disrupted, you will find the vehicle acting weird when it comes to turning the wheels or accelerating the speed. The cranking sound and slight bumping can be some of the common symptoms of a bad CV joint.

How Many Types of CV Joints Are There?

Before we delve into the issue of how a CV joint works, you first need to understand that there are plenty of CV joints out there. Primarily divided into three groups - coupling type, sliding type, and fixed cup type, there are generally 6 different types of CV joints you can find in details. The most common CV joints are-

  • Rzeppa CV Joints
  • Fixed and Plunge Joints
  • Tripod and Ball-type Plunge Joints
  • Tripod Joints
  • Fixed Tripod Joints
  • Inboard and Outboard Joints

How Does a Constant Velocity Joint Work?

Well, as we have seen, CV joints are of 6 types, but as we need general knowledge on how the CV joints work, we will be picking up two common joints to explore them. One outboard joint - Rzeppa joint, and one inboard joint - Tripod joint.

How Do Rzeppa Joints Operate

A US engineer, Alfred Hans Rezeppa, from Ford Motor Company, invented the Rzeppa joint in 1926. He later patented it in 1935. No wonder he patented it after his own name. This is a fixed type joint that can easily twist at the highest angle of 55-degree. But at the same time, it doesn’t have any horizontal travel.

It comes with four parts - an outer race, a cage, an inner race, and ball bearings. Now the course of action follows the following pattern.

  • At first, you turn on the car engine
  • The input shaft of the joints starts spinning as soon as the car engine turns on
  • The ball bearings move to the top of the inner ring
  • The ball bearings are placed and sheltered in a cage with a spherical shape
  • The outer race of the joint come with grooves that allow the ball bearings to fit inside
  • The outer race has a connection to the output shaft
  • The output shaft has a connection to the vehicle wheels

The ball bearings are the actual parts that do the job. These bearing are placed in the middle of the inner and outer shaft and transfer power from one to the other.

How Do Tripod Joints Operate

Now comes the inboard joints - the tripod joints. These joints were first made by a Frenchman known as Michel Orain of the Glaenzer Spicer company. He patented in the year 2000.

The tripod joint is a sliding type joint that can easily twist at 25 to 26 degrees. Plus, it can move up to 51mm of axial travel if you are using the best replacement CV axles. The joint consists of a spider, needle bearing, 3 roller bearings, an outer housing.

Now, this is how exactly it goes.

  • The outer housing of the tripod joint is placed and connected to the transmission of the vehicle
  • As soon as the engine starts, the transmission starts to rotate. The outer housing also follows it in rotation
  • Now this power that is produced by the rotation is swiftly transferred to the inner shaft
  • Next, the power is once again transferred to the outboard joint - the Rzeppa joint
  • Both the needle and roller bearings are placed inside the housing in grooves

Now, why exactly do you need the tripod joint as the inboard CV joint? This is because the cost of the tripod joint is really in our reach, and still, it does a great job as you need it.

As for the operating angle, this one is attached to the actual vehicle transmission inside, which is strongly placed in the center of the vehicle. That’s why the angle doesn’t even cross the 20-degree angle mark.

As you turn your wheels of the car, it’s the outer joint that is actually carrying on the task of twisting and rotating.

Final Words

So now that you know how does a constant velocity joint work, it’s evident that you can troubleshoot your own car’s CV joint issues. Although you can always go for a thorough check up at the mechanics, examining your own car with your own knowledge is always better.

So, the next time you hear a cranking sound when the wheels are turning, there’s nothing to get scared about. Simply pull off the vehicle and have a close look at the CV joints to make sure they are in good condition.

If you find any anomaly, take immediate action!

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One comment

  1. […] CV joints are usually found in the wheel-area of the wheels that actually turn the vehicle. If you are driving a front-wheel turning vehicle, the joints will be there. If you are using a car that comes with a rear-wheel turning vehicle, the joints will be on the rear wheels. So, it’s kind of a must for you to know how constant velocity (CV) joints work. […]

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