What Is Stub Axle?

A stub axle, often referred to as stub axel, is one of the types of front axle that hold one wheel in a rear-wheel-drive vehicle. It’s essential to understand what is a stub axle and its significance. The axle is capable of limited angular speed about the kingpin to drive the vehicle.

The stub axle assembly has wheel bearings that support the wheel hub, and for a clearer understanding, a stub axle diagram can be referred to. The stub axle is a sub-assembly of the front axle beam on which the road wheel mounts.

The stub axle is attached to a front axle using a kingpin. These stubs revolve around the axle kingpin, which is a light drive that fits into the axle beam eye, which is located and locked by the taper cotter pin.

Types of Stub Axle:

As The Engineers Posts explains, when discussing the type of axle, there are four primary types of stub axle.

1. Lamoine Type Stub Axle

The front axle makes the eye for support on the beam and stub axles. The stub axle and kingpin are integrated to form the reverse. The front axle is found in the L shape assembly. Thrust washer place between stub axle and front axle beams.

Here the cotter pin in the joints is used to lock the front axle in positions. The kingpin is free to roam in the bushes placed in the eye of the front axle. The thrust washer carries a vertical load in the joint.

2. Elliot Type Stub Axle

This type of stub axle attaches to the front axle by placing it in the yoke end with a kingpin & a cotter to connect the two together. The swivel pins are usually fixed in the stub axle forging, which is intended to forcibly close the axle beam.

The axle beam is formed as a gamble and receives a stub axle. Thrust washer location on top of the stub axle.

3. Reverse Elliot Type Stub Axle

The reverse Elliott-type stub axle forms the fork end to receive the front axle beam. The front axle forms the end eye, and the thrust washer is placed under the front axle beam on the contact faces with the stub axle.

The cotter pins in the joints lock the speed of the kingpin in the front axle. Phosphors placed in the eye of the kingpin fork end are free to move into bronze bushes.

The thrust washer carries a vertical load at the joint and is used to extend the life of both the stub axle and the front axle. The stub axle is formed as a yoke and receives the front axle. The thrust washers are placed at the bottom.

4. Reverse Lamoine Type Stub Axle

The front axle forms a beam-end eye to support the stub axle. The stub axle and kingpin are integrated to form an inverted L-shaped assembly to obtain the front axle.

The thrusts washers are placed at the bottom, as shown in the figure. To lock the cotter pin front axle into position in joint use.

The kingpin is free to roam in the bushes placed in the eye of the shaft. The thrust washer carries vertical loads, and it extends the life of both the stub axle and the front axle.

What Is Front Axle?

The front axle, one of the front axle types, is used to carry weights of the front section of the vehicle. A front axle diagram can provide a visual representation of its structure., as wells, as facilitates steering & to absorbs shocks due to changes in the road surface.

It is made up of an I-section in the center position, while the ends are made either circular or oval. It takes the bending load and also the torque due to the braking of the wheel.

To keep the height of the chassis low, its middle section gives a down-step sweep. Sometimes it also delivers torque from differential to drive wheels.

The Necessity of Front Axle:

Front axles are necessary to carry and support a portion of the vehicle’s weight and facilitate steering and absorb the road shock as well as the torque applied to the vehicle’s braking. And sometimes, it transfers torque from differential to drive wheels.

Classification of Axle:

1. Live Front Axle

The live axle receives powers from the gearbox & transmits them to the road wheels. It is an axle with a differential mechanism through which the power of the engine flows towards the front of the wheels.

To drive the front wheel, a constant velocity joint includes a half shaft; These joints help to bend the stub axles around the kingpin.

2. Front Dead Axle

Is it just a dummy axle that has no connection to the engine? Unlike live axles, these axles do not rotate with the driver. The dead front axle has sufficient rigidity & strength to carry the weight of the vehicle from the springs to the front wheels.

The ends of the axle beam are appropriately shaped to assemble the stub axle. To accommodate a swivel pin connecting the sub-axle portion of the assembly, the terms of a portion of the beam are usually shaped as either a yoke or an unfrozen surface with a drilled hole.

Different Types of Axle:

The axis is divided into three categories:

1. Rear Axle

The rear axle is in charge of supplying power to the drive wheels. It is made up of two parts, known as half shafts, which are connected by a gap. Rear axles are usually live, meaning that they rotate along with the car’s wheels.

2. Front Axle

The front axle, which is located in front of the car, is in charge of assisting with steering and processing shock from the bumpy surface of the road.

Beam, swivel pin, track rod, and stub axle are the four main components. The front axles should be as strong as possible, which is why they are usually made of carbon or nickel alloys.

3. Stub Axle

Stub axles are attached to the front wheels of the vehicle and are connected to the front axle by the kingpin.

4. Dead Axis

Because the dead axle is not connected to the engine, it is called a dead axle and will not express the power of the engine. A dead axis sometimes referred to as a lazy axis, is a non-powertrain axis that rotates freely.

Many vehicles and trailers have dead axles for load-bearing reasons alone. A dead axle that sits right in front of the driving axle is known as a pusher axle. A dead axle that is in front of the driving axle is known as a tag axle.

Dead axles are found on semi-trailers, agricultural equipment, and some heavy construction equipment. On some cars, the tag axle may be playable. In some configurations, the wheels on a lazy axle may contact the ground only when the weight is considerable.

5. Live Axle

A live axle is a form of beam axle that provides power to the wheels through the shaft. The term “live axle” refers to an axle with a differential system that directs the power of the engine to the front wheels.

In addition to transferring weight, the live axle must also provide engine power to the wheels.

Although the Live Axle, also known as the Solid Axle, is still used in light trucks and some SUVs, current muscle cars such as the Mustang, Camaro, and Challenger now use independent rear suspension.

The wheels are attached to live axles, which move around with them. Live automobile axles, which push a set of wheels, are found in all vehicles moving on wheels. This type delivers powers & torque to the wheels while supporting the vehicle’s load.

Semi Floating Axle of Live Rear Axles:

The semi-floating live rear axle is shown in the diagram. The short rear axle shaft inner end only supports differential side gears.

The differential case carries the internal bearing between it and the axle shaft housing that supports it. Thus the inner end of the axle shaft is freed from the function of supporting the weight of the vehicles.

The weight of the vehicles is supported by the axle housing. Now the outers end of the axle supports the weights of the vehicles & takes the end thrust.

Therefore, this construction is called a semi-floating rear axle. The inner end of the axle shafts is divided into differential side gears. The outer end is flanged, & the wheel is bolted directly to it.

In some designs, the hubs of the wheel are placed at the outer end of the axle shaft. The axle housing supports wheel bearings, which are placed inside the outer end of the axle housing.

The bearing is mounted on an axle by a retainer. The bearing is mounted on an axle by a retainer. Most axle bearings are pre-lubricated. With this arrangement, the brake drum, wheel, and bearing retainer plate must be removed to retract the axle shaft.

As a result of this arrangement, the axle shaft helps support the weight of the vehicles in addition to transmitting rotations to the wheels. Semi-floatings live rear axles are found in cars, SUVs, & mid-size trucks such as 1/2 ton trucks and light-duty pickup trucks.

Three Quarter Floating Axle of Live Rear Axles:

The three-quarter floating live rear axle is shown in the figure. In this axle, the wheel hub is supported by single bearings located at the center of the wheel hub. The wheel hub moves on the axle housing.

The axle shaft is rigidly attached to the wheel hub. This arrangement provides the driving connection and maintains the alignment of the wheel. The construction at the inner end of the axle shaft is similar to the semi-floating type. This axle is not supported by bearings at either end.

The three-quarter floating live rear axle has only one bearing at its outer end. It is not quite as full floating type

Full Floating Axle of Live Rear Axles:

The full floating live rear axle is shown in the diagram. In this axle, the wheel’s hub is supported by two bearings. The bearings are run directly on the axle housing.

The axle shaft is connected to the wheel hub flange through couplings. Through coupling, the rotary motion of the axle shaft is transmitted to the hub & wheel. With this arrangement, the axle shafts can be removed from the housing without disturbing the wheels by removing the hub cap and couplings.

In full-floating axles, the axle shaft is not supported by bearings at either end. The position of the axle shafts is maintained in such a way that it is supported at both ends.

As such, the axles are relieved of all the stress caused by the weight of the vehicle or the final thrust. Now, the only function of the axle shafts is to deliver rotary speed or torque to the wheel.

Due to this fact, the axle is called a full floating live rear axle. The full floating axle is the only construction that keeps the wheel in position even when the axle shaft is broken. In other variants, the wheel stops and drops the vehicle.

Full-floating axles are used almost exclusively in trucks. In all applications, either tapered roller or ball bearings are used in axle manufacturing.

Larger vehicles, such as heavy-duty trucks, benefit from a fully floating live rear axle. Full-floating live rear axles may support some mid-size trucks that have a high towing capacity or that often use four-wheel drive.

FAQ: Comprehensive Guide to Stub Axles

What Is a Stub Axle?

A stub axle, also known as a stub axel, is a type of front axle that holds one wheel in a rear-wheel-drive vehicle. It allows for limited angular movement around the kingpin to drive the vehicle.

What Is the Function of a Stub Axle?

The stub axle supports the wheel hub through wheel bearings and is part of the front axle assembly. It connects to the front axle via a kingpin and allows for rotational movement, facilitating steering and handling.

How Is a Stub Axle Attached to a Front Axle?

A stub axle is attached to a front axle using a kingpin. The kingpin fits into the axle beam eye and is secured with a taper cotter pin, allowing the stub axle to revolve around it.

What Are the Main Types of Stub Axles?

The four primary types of stub axles are:

1. Lamoine Type Stub Axle
2. Elliot Type Stub Axle
3. Reverse Elliot Type Stub Axle
4. Reverse Lamoine Type Stub Axle

What Is a Lamoine Type Stub Axle?

In a Lamoine Type Stub Axle, the front axle forms an eye for support, and the stub axle and kingpin are integrated into an L-shaped assembly. Thrust washers are placed between the stub axle and front axle beams to carry vertical loads.

What Is an Elliot Type Stub Axle?

An Elliot Type Stub Axle attaches to the front axle by fitting into the yoke end with a kingpin and a cotter pin. The axle beam is designed to receive the stub axle, with thrust washers placed on top.

What Is a Reverse Elliot Type Stub Axle?

A Reverse Elliot Type Stub Axle has a fork end to receive the front axle beam, with thrust washers placed under the front axle beam. The kingpin is free to move within bronze bushes placed in the eye of the kingpin fork end.

What Is a Reverse Lamoine Type Stub Axle?

In a Reverse Lamoine Type Stub Axle, the front axle forms a beam-end eye to support the stub axle. The assembly is inverted into an L-shape, with thrust washers placed at the bottom to carry vertical loads.

What Is the Significance of a Front Axle?

A front axle supports a portion of the vehicle’s weight, facilitates steering, absorbs road shocks, and sometimes transfers torque from the differential to the drive wheels.

What Are the Different Types of Axles?

The different types of axles are:

1. Rear Axle
2. Front Axle
3. Stub Axle
4. Dead Axle
5. Live Axle

What Is a Live Front Axle?

A live front axle receives power from the gearbox and transmits it to the road wheels. It includes a differential mechanism that directs engine power to the front wheels.

What Is a Dead Front Axle?

A dead front axle does not receive power from the engine. It is primarily a dummy axle used to support the vehicle’s weight and facilitate steering.

What Is a Semi-Floating Axle in a Live Rear Axle?

A semi-floating axle supports the vehicle’s weight partially. The inner end supports differential side gears, while the outer end supports the vehicle’s weight and takes the end thrust.

What Is a Three-Quarter Floating Axle?

A14: A three-quarter floating axle has a single bearing at the center of the wheel hub, which moves on the axle housing. It provides the driving connection and maintains wheel alignment.

What Is a Full Floating Axle?

A full floating axle has two bearings running directly on the axle housing, supporting the wheel hub. The axle shaft transmits rotary motion to the hub and can be removed without disturbing the wheels.

Where Are Full Floating Axles Typically Used?

Full floating axles are used in larger vehicles, such as heavy-duty trucks, to support significant weight and provide durability. They are also used in some mid-size trucks with high towing capacities.