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The differential is a complex mechanism designed to transfer torque from an engine onto wheels for vehicle movement. Comprised of various parts, each part serves its own specific function in this complex mechanism.
Common components include the differential case or carrier, which contains various gears and bearings as well as its crown wheel for attaching to the drive pinion.
1. Axle Shafts
Axle shafts play a pivotal role in your vehicle’s drivetrain. As the central link between transmission, wheel hub and driveway, and wheels, they transfer power and torque from your differential to all four of them.
Axles play an integral part in maintaining proper alignment and stability. Axels must endure constant rotational forces, sudden stops/starts, varying loads conditions, rough road surfaces and rougher weather – they must all be capable of withstanding these stresses without fail.
These shafts are then pressed into ball or tapered roller bearings which are secured within/onto axle housings using flanges, bolts and nuts; this design is known as “semi-floating”, since axial loads only are placed upon them without bearing any radial loads.
Full-floating axles use a hub with two bearings mounted to a spindle protrusion at the end of their housing rather than having an attached flange to support weight distribution from their vehicle’s weight onto an axle shaft. This design makes a much stronger product.
These axles can be found in light, medium-duty and heavy-duty trucks as well as some rear-wheel drive cars.
Axle shafts are typically composed of chromoly (chromium-molybdenum steel), known for its malleability, tensile strength, and flexural memory properties. Chromoly is often utilized when building high performance or off road components due to its ability to withstand harsh environmental conditions and rapid temperature shifts.
Differential Shafts are an integral component of your differential assembly and can be divided into three major types: half shafts, universal joints and ring gears. Your axle’s pinion gear connects with your differential’s ring gear which then transmits power from transmission to wheels via transmission shafts.
Your differential’s ring gear is connected to a large pinion gear on one of your axle shafts, whose rotating mechanism causes its ring gear to turn in turn, distributing power and force across both axle shafts.
Differentials are designed to withstand stress during regular motoring, yet they may still break when on an extended drive. Your differential may fail when its ring gear or pinion breaks, causing your vehicle to no longer function as intended – that is why replacing it when necessary is so essential.
2. Gears
Gears are used to allow a differential between axles of a machine to function optimally in its drive system, making turning easier, reducing wear on tires and tracks and accommodating torque differentials between left and right wheels.
An automotive differential assembly utilizes various gears, including spider (also called pinion) gears and side gears, that transmit power from its big ring gear to each axle of the vehicle.
Differential assemblies enable transmissions to send various amounts of power and torque directly to each wheel, helping the car turn faster while less easily in corners, thus decreasing tire wear.
Gears in differential assemblies typically consist of gears fabricated from various metals such as aluminum, magnesium and steel – these materials being costly to produce, which drives up costs associated with differential assembly.
Manufacturing differential gears is a complex process requiring forging, annealing, rough machining and carburizing processes – each operation adding costs that increase the price of assembly significantly. Scrap material generated during this phase also adds to costs significantly.
Therefore, it is desirable to develop a method for producing differential gears that enables lower-cost processes without compromising on quality or functionality. This invention solves these problems by offering an approach for producing differential gears using a heated tubular preform.
This tubular preform is placed into a die and formed into a gear with multiple teeth circumferentially surrounding an aperture. It includes an internal spline for drivingly interconnecting its first side gear with an axle half-shaft rotatably mounted within an axle housing.
Tubular preforms are then heated until their outer cylindrical surfaces engage an outer cylindrical surface of a pin in the die and formed into net shapes around their inner cylindrical surfaces for forging in the die, producing a gear with multiple driveable contact surfaces that has then been hardened for increased strength and durability.
3. Crown Wheel & Pinion
Crown wheel and pinion gears are essential components in differential assemblies, helping power transfer from engine to front wheels efficiently. This is especially useful for motorway travel where there may be increased traction or torque requirements on vehicles.
Backlash, the free clearance between meshing teeth of crown wheel and pinion gear sets, is essential to maintaining an efficient gearing system.
Backlash settings vary depending on the make and model of vehicle. When exceeded, backlash prevents proper mesh between crown wheel and pinion and causes wear and damage to gears, reducing their effectiveness over time.
Before dismantling a crown wheel and pinion assembly, it is imperative to inspect it for any wear or tear in order to detect potential issues before they worsen. Doing this will allow any issues that may arise to be identified early and addressed as soon as possible.
As this will prevent damage to your differential gears during dismantlement and assembly, replacing them may become necessary if damage does occur.
Rear-Axle Differentials This type of differential can usually be found at the rear of a vehicle, consisting of a housing that contains crown wheel, pinion gears and differential gears. The housing may either be banjo-type or unitised with both crown wheel and pinion bolted directly onto its faceplate.
Banjo-type units This type of axle is commonly found on small and medium passenger cars, station wagons and commercial vehicles. Constructed of pressed steel for strength and consisting of a housing that holds crown wheel, pinion gear and differential gear assemblies – banjo axles have become an industry standard over the years.
The pinion is secured to the crown wheel via an internal ring with an integral stop body that helps prevent any radial displacement of its position.
In one embodiment of the invention, this is accomplished by applying a radially inwardly increasing head shortening to the teeth of a pinion gear, helping increase durability of crown gear and pinion pairing by eliminating an undercut of teeth that weakens them and leads to wear and tear.
4. Bearings
Differential bearings are an integral component of differential assemblies, helping distribute engine driving force evenly over all four wheels while mitigating wear-and-tear, decreasing fuel consumption by providing low friction torque, and acting as an antiwear measure.
A differential assembly consists of many parts, such as a gear case, pair of hypoid gears and pinion gear. Additionally, this device also comes equipped with various bearings, seals and shims for optimal operation.
Some bearings are fixed to the gear case and pinion, while others can be removed easily. Most of these bearings are made of durable metals with high-strength construction to provide optimal protection for your car’s gears, while having long service lives even under difficult conditions such as dirty gear oil.
Differentials utilize two kinds of bearings: screw and shim-type bearings. Screw bearings tend to be small in size and installed from within the gear case, while larger shim bearings can be found atop each gear.
An essential step when building a differential is checking and adjusting its side bearings, either using adjustable screw nuts or by shimming in and out to create just the correct amount of backlash.
Before adjusting the side bearings, it is essential to measure their preload so you understand how much room there is for movement. A pull scale and cord can be used to make this measurement.
After measuring the preload, tighten the adjusting screws until all shims are touching crown wheel and pinion teeth. This should only take a few minutes for quality adjustments to last over time.
Once you’ve installed the appropriate amount of shims, the next step in assembly should be assembly of the differential. Place both its case and crown wheel onto pedestals of its differential carrier before installing bearing cups over bearing cones and installing adjusting nuts into threaded pedestals ensuring they turn easily without interfering with one another.