Assembling an Automotive Differential with 3D Printed Parts

Automotive transmission systems are essential to the performance, safety and efficiency of any vehicle. Among these systems, the automotive differential plays a crucial role. Responsible for allowing a vehicle's wheels to rotate at different speeds while receiving power from the engine, the differential is fundamental to the car's stability and maneuverability, especially when cornering. Without it, the inner and outer wheels, when turning, would be forced to rotate at the same speed, which could cause slipping, excessive tire wear and driving difficulties.

The invention of the differential dates back to ancient times, but its improvement and practical application in the automotive sector were only consolidated with the advancement of mechanical engineering. The basic mechanism involves a set of planetary gears that redistribute torque between the wheels, compensating for the difference in speed required while driving. The integration of this system with modern engines, whether internal combustion or electric, has evolved to improve the energy efficiency and dynamic performance of vehicles, adapting to the demands of a market increasingly oriented towards technological innovation.

This article will not only explore the fundamental principles of the automotive differential, but also demonstrate, step by step, how to assemble this mechanism using 3D printed parts and a DC motor to transmit motion. With a detailed design and clear instructions, you will be able to understand and replicate the operation of this vital component. Read on to discover how 3D printing technology is revolutionizing mechanical systems prototyping and education, bringing complex concepts into practical, accessible reality.

Development of the Automotive Differential Mechanism

The automotive differential mechanism is an essential part of the transmission system that allows a vehicle's drive wheels to rotate at different speeds, which is crucial during cornering.

The differential is made up of a set of planetary gears: a central gear called the ring gear, which is connected to the transmission shaft, and two satellite gears connected to each axle shaft of the wheels. When the vehicle moves in a straight line, the satellite gears do not rotate around their own axes, and the engine power is distributed equally to both wheels. However, when turning, satellite gears allow one wheel to turn faster than the other, compensating for the difference in distance each wheel must travel.

During a turn, the outside wheel needs to travel a greater distance than the inside wheel. The differential accommodates this difference by allowing the inside wheel to turn more slowly and the outside wheel to turn faster, maintaining traction and vehicle stability. This is achieved because the satellite gears within the differential rotate around their own axes, in addition to rotating around the central axis, distributing torque variably between the wheels. This differential feature is crucial to prevent excessive tire wear and transmission stress, improving vehicle efficiency and providing a smoother, safer drive.

In addition to the basic function of allowing different wheel speeds, the differential can also be configured to optimize traction in adverse conditions, such as on slippery roads or off-road. Limited slip differentials (LSD) and lockable differentials are variations that provide greater control and performance. LSD limits the speed difference between the wheels, providing more torque to the wheel with the most traction. The lockable differential allows both wheels to rotate at the same speed when necessary, such as in rough terrain. Understanding how the differential works and its variations helps to appreciate the complexity and importance of this component in the vehicle's overall performance.

The structure of the differential mechanism is presented below. See the complete structure. All parts of the mechanism were printed with SLA technology, using resin, at JLC3DP. There are different types of resin materials and some pieces can be obtained for as little as $0.3.

The automotive differential mechanism is made up of several main parts, each playing a crucial role in its operation. Firstly, the gear set is fundamental. This includes bevel gears, which allow the distribution of power in a balanced manner between the wheels, and satellite gears, which facilitate the difference in speed between the wheels during curves. The gears are mounted inside the differential case, which serves as the supporting structure for the entire system and keeps the gears in correct alignment.

Another essential component is the pinion, which is connected to the transmission shaft and transmits power from the engine to the differential gear set. The set is complemented by the crown, which is coupled to the pinion and the differential housing, allowing movement transfer. In addition, there is the semi-axle, which connects the differential to the wheels, transmitting the generated torque. Together, these components work harmoniously to allow the wheels to move at different speeds, ensuring smooth and efficient driving, especially when cornering.

The first step in assembling the mechanism is fixing the axle to the side wheels with the help of 2 screws. See the structure below. Repeat the process for the left side.

From this assembled wheel structure, we must assemble the differential mechanism structure. This mechanism is formed by the combination of 4 gears. A pair of gears represented in the following figures.

From the combination of gears, it is necessary to use a shaft with a union of a pair of gears. See the structure below.

Now it is necessary to assemble the central system of the automotive differential mechanism. This part is the heart of the mechanism. To do this, we must assemble the structure below. It is used to assist in coupling the 4 gears.

After assembling this gear coupling, it is necessary to assemble the structure with the gear that is coupled directly to the DC motor movement transmission system.

From this assembled structure, we must attach it to the support base. See the structure of the support base in the figure below.

From the structure above, we must couple the two wheel axles that will rotate based on the movement of the central gears of the mechanism.

After fixing the wheels, it is necessary to couple the transmission motor. For this, we use a 100RPM N20 engine. See the engine below. Its shaft must be coupled to a gear that will be coupled to the larger gear.

The support base structure has a space reserved for coupling the motor body. See below the process of installing the motor on the support base.

After fixing the engine, the protective cover on its body is installed. See the figure below.

This structure represents the step-by-step assembly of the automotive differential mechanism. Each part is crucial for the structure to function correctly.

Next, see how the assembled system works: https://www.youtube.com/watch?v=823fDJo94wI

Conclusion

After watching the video of how the automotive differential mechanism works, it becomes clear how this innovation is fundamental to ensuring safe and efficient driving. Composed of essential components such as bevel gears, satellite gears, pinion, ring gear and half shaft, the differential allows the vehicle's wheels to rotate at different speeds, essential for curves and maneuvers.

In the current context of advanced manufacturing, JLC3DP stands out for its ability to produce high-quality parts for this mechanism, using 3D printing in resin with a high level of surface finish. The industrial quality of the parts printed by JLC3DP guarantees the precision and durability necessary for the differential to function perfectly. Furthermore, with an affordable cost of just $0.3 per part, the JLC3DP offers an economical and efficient solution for companies in the automotive sector, significantly contributing to innovation and technological advancement in the manufacturing of automotive components.

We invite you to learn about JLC3DP's services and take advantage of this unique opportunity to print your first parts with industrial quality and low manufacturing costs. Don't miss the discount coupons available for new customers and discover how JLC3DP can transform your projects with precision and savings. Visit our website and take the first step towards integrating cutting-edge technology and savings into your operations.