Differential And Rear Axle PdfBy Margalit Z. In and pdf 04.12.2020 at 06:26 8 min read
File Name: differential and rear axle .zip
A differential is a gear train with three shafts that has the property that the rotational speed of one shaft is the average of the speeds of the others, or a fixed multiple of that average.
- Types of Differential and How They Work
- Rear Axle Assembly Construction and Operation
- Differential gear
Types of Differential and How They Work
Like most things on modern automobiles, the simple piece of gearing known as a differential has seen constant refinement and experimentation - leading to a range of types each with their own advantages and disadvantages. The concept of the differential — that is, to allow wheels mounted on the same axle to rotate independently of each other — is an ancient design, with the first known instance of its use recorded in China during the 1 st millennium BC.
But this was far from ideal as it meant they were underpowered and encountered frequent problems with traction on anything other than firm, level ground.
Eventually this led to the development of the Open Differential before other more complicated types were developed to overcome more complex driving conditions. A differential in its most basic form comprises two halves of an axle with a gear on each end, connected together by a third gear making up three sides of a square. This is usually supplemented by a fourth gear for added strength, completing the square. This basic unit is then further augmented by a ring gear being added to the differential case that holds the basic core gears — and this ring gear allows the wheels to be powered by connecting to the drive shaft via a pinion.
In this example you can see the three sides of the internal gearing that make up the core mechanism, with the larger blue gear representing the ring gear that would connect to the drive shaft. The left image shows the differential with both wheels turning at the same speed, while the right image illustrates how the inner gears engage when one wheel turns slower than the other.
This gearing arrangement makes up the open type differential, and is the most common type of automotive differential from which more complicated systems are derived. It does also benefit from its basic design being relatively cheap to produce. The disadvantage of this type is that because the torque is split evenly between both wheels, the amount of power able to be transmitted through the wheels is limited by the wheel with the lowest amount of grip.
Once the traction limit of both wheels combined is reached, the wheel with the lowest amount of traction will begin to spin — reducing that limit even further as there is even less resistance from the already spinning wheel. The locked or locking differential is a variant found on some vehicles, primarily those that go off road.
It is essentially an open differential with the ability to be locked in place to create a fixed axle instead of an independent one. This can happen manually or electronically depending on technology in the vehicle. The benefit of a locked differential is it is able to gain a considerably greater amount of traction than an open differential.
One disadvantage of locked diffs is called binding, which occurs when excess rotational energy torque is built up within the drive train and needs releasing — typically achieved by the wheels leaving the ground to reset the position. Or by simply releasing the locks once they are no longer needed.
Welded differentials are essentially the same as a locked differential, only it has been permanently welded from an open differential into a fixed axle also known as a spool diff. There are two categories which use different forms of resistance to achieve the same effect:.
This type of LSD surrounds the same core gearing seen in the open diff with a pair of pressure rings, which exert force on two sets of clutch plates positioned alongside the gears. This provides resistance to the independent rotation of the wheels changing the effect of the differential from open to locked — and providing it with the increased traction this type benefits from over an open differential. In this cutaway, you can see the the pressure rings also cut away surrounding the core gears, which are forced apart by the central gear pins pushing against the angled surfaces under rotation.
This movement pushes the pressure rings onto the clutch packs yellow and blue on either side, generating resistance and changing the behaviour of the axle from an open to a fixed type of effect.
The downside to mechanical LSDs is they require regular maintenance to keep operational and are prone to wearing out completely, making for an expensive part replacement. The second type of limited slip differential, they instead use a thick liquid in place of clutches to create the resistance needed to alter the differentials behaviour between open and locked.
VLSDs are also able to direct torque more effectively to the wheel that has more traction. Because the fluid acts to be resistant under speed, if a wheel ever loses traction and spins the difference in speed between the two wheels inside the differential creates more resistance on the slower moving wheel - channelling more torque from the drive shaft to it.
VLSDs do become less effective with prolonged use, as the fluid heats it becomes less viscose and provides less resistance. It also cannot lock as fully as a mechanical LSD due to a fluid being unable to provide absolute resistance within an adequate space.
A disadvantage with both mechanical and viscous LSDs is that the system does not always channel torque effectively during high speed cornering, as it can interpret the faster moving outer wheel as losing traction. The Torsen Tor que — Sen sing differential employs the use of some clever gearing to produce the same effect as a limited Slip Differential without the need for clutches or fluid resistance.
These sets of worm gears acting on each axle provide the resistance required to enable torque transfer, which it then achieves by having the worm gears in constant mesh with each other via connected spur gears.
While the first and second images are of the orginal torsen design, the third image is of the second version of the torsen differential. This removes the power limitation that open differentials suffer because the amount of torque available is not being limited by the amount traction in either wheel.
This all achieved mechanically without the use of electronics or any form of perishable part being sacrificed for friction, and overall the Torsen differential is the superior mechanical system that combines the primary benefits of all the previous differential types listed. Very similar to a limited slip differential, the active differential still employs mechanisms to provide the resistance needed to transfer torque from one side to another - but rather than relying on purely mechanical force, these clutches can be electronically activated.
The active differential can use electronics to artificially alter the mechanical forces the system is experiencing through changing driving conditions.
This drastically improves performance, especially over imperfect road surfaces, and is particularly favoured by rally drivers whose cars endure rapidly changing driving conditions and need a system that can keep up with their continuous adjustments to the vehicle. The TVD takes this electronically enhanced system even further by using it to manipulate the angle, or vector, of the vehicle in and out of the turns by encouraging specific wheels to receive more torque at key moments - improving cornering performance.
By activating the opposite clutch to what a purely mechanically driven LSD would normally engage, you can use the effect to assist with steering while also putting more power down, overcoming the deficiencies in the LSD system. This imbalance of power to the outside encourages the vehicle to turn into the corner sharper and reducing understeer.
This allows for greater acceleration out of the corner while the car's turning abilitty is increased. Every system has it owns benefits and disadvantages, and although the more complicated systems are generally superior they have an attached cost that far exceeds the simpler systems.
As with everything automotive, how much benefit you will gain from each system comes to down to what exactly you will be doing with your vehicle and what you need your differential to be capable of. Types of Differential and How They Work Like most things on modern automobiles, the simple piece of gearing known as a differential has seen constant refinement and experimentation - leading to a range of types each with their own advantages and disadvantages.
Watch this video which explains with 3D imagery how the following types of differential work:. Found this post useful? Why not share it with your network:. Back to Listing. Previous Next. Instagram Feed Latest Vacancies.
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Rear Axle Assembly Construction and Operation
Differential gear , in automotive mechanics, gear arrangement that permits power from the engine to be transmitted to a pair of driving wheels, dividing the force equally between them but permitting them to follow paths of different lengths, as when turning a corner or traversing an uneven road. On a straight road the wheels rotate at the same speed; when turning a corner the outside wheel has farther to go and will turn faster than the inner wheel if unrestrained. It was used first on steam-driven vehicles and was a well-known device when internal-combustion engines appeared at the end of the 19th century. The elements of the Pecqueur differential are shown in the Figure. The power from the transmission is delivered to the bevel ring gear by the drive-shaft pinion, both of which are held in bearings not shown in the rear-axle housing. The case is an open boxlike structure that is bolted to the ring gear and contains bearings to support one or two pairs of diametrically opposite differential bevel pinions.
With a limited-slip differential, the lock-up can be achieved one of three ways — a viscous fluid, a clutch park or a complex gear train. Each type of differential has its own challenges, and it takes an expert in automotive repair to understand how to best service your unique car. Fortunately, the experienced auto repair experts at our Independence auto shop are trained to handle every type of differential on any kind of car or truck — even foreign and luxury cars! Call our shop near Blue Springs, Missouri to make an appointment today, and discover the nice difference! Blog Home Sep 12, Sep 12, Share. Open Differential Splits the engine torque into two outputs Allows the wheels to rotate at different speeds When one tire loses traction, the opposing tire will also lose power Found in family sedans and economy cars Locking Differential Connected wheels always spin at the same speed Turning the vehicle can be very difficult Found in Jeep Wranglers and most full-size trucks Limited-Slip Differential Combination of open and locking differentials Usually acts as an open differential Automatically locks when slipping occurs Found in sports vehicles like Nissan Z and the Mazda MX-5 Miata With a limited-slip differential, the lock-up can be achieved one of three ways — a viscous fluid, a clutch park or a complex gear train.
6. Understand basic service and repair of a differential. 7. Understand the adjustment of the ring and pinion gears. 8. Identify the parts of the rear drive axle and.
Like most things on modern automobiles, the simple piece of gearing known as a differential has seen constant refinement and experimentation - leading to a range of types each with their own advantages and disadvantages. The concept of the differential — that is, to allow wheels mounted on the same axle to rotate independently of each other — is an ancient design, with the first known instance of its use recorded in China during the 1 st millennium BC. But this was far from ideal as it meant they were underpowered and encountered frequent problems with traction on anything other than firm, level ground. Eventually this led to the development of the Open Differential before other more complicated types were developed to overcome more complex driving conditions.
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