Common Automotive Gear Materials and Their Applications in Vehicle Systems

Why Gear Material Selection Matters in Automotive Systems?

The basic function of the gears is torque transmission. Torque is the rotational force in the vehicle; gears help transmit(regulate) torque during acceleration. The lower gear (a higher numerical ratio) will transmit more torque for climbing hills and towing heavy loads.

The gear transfers motion from the crankshaft to the driveshaft, which ultimately leads to the wheels. In vehicles, gears can also perform a reverse action during turns.

Maintaining the powertrain's rotational speed is the primary function of the gear in a vehicle. The lower gears help maintain higher RPM, and vice versa.

Two kinds of gears could be used in a vehicle. Knowing the differences between high-load transmission gears and small-motor gears will help you understand the concept.

• High-load transmission gears transmit power and torque in heavy machinery. These gears are larger, with higher helical sets or multiple ratios.
• Lower-power devices use small motor gears for power and torque transmission. These gears are smaller and have simple spur gears.

The selection of the right material is important because an incorrect choice can trigger a chain of mechanical, safety, performance, and economic problems in automotive systems. The effects are often severe, costly, and sometimes dangerous. When selecting gear material, it is important to balance manufacturability, cost, and mechanical properties.

The vehicle's gear must be reliable enough to withstand millions of cycles without damage, thereby avoiding repair and replacement costs. Noise reduction is achi eved by selecting helical gears instead of spur gears, which maintain peace inside the cabin. The gear must have high wear resistance to maintain the transmission life and reduce maintenance costs.

Gear Materials in the Automotive Industry

Various materials can be used to manufacture vehicle gears. The details of all these materials are as follows:

· Steel Alloy Gears: Strength and Durability

The most common manufacturing material for gears is steel and its alloys. It provides high resistance, strength, toughness, and heat resistance.

• The carbon content of steel determines its strength. The concentration of carbon is around 0.3-0.6%. Carbon steel is the cost-effective solution for durability, strength, and heat resistance.
• The 20CrMnTi alloy contains chromium, titanium, and manganese. The alloy provides high hardenability, fatigue, and wear resistance.
• The 18CrNiMo7-6 alloy is designed to withstand heavy loads and deliver high performance.

Advantages

• The steel alloy has high tensile strength, meaning it can withstand pressures greater than 1080 MPa.
• 18CrNiMo7-6, 20CrMnTi, and carbon steel alloys have high durability and greater heat resistance.

Applications

• The most common use of the steel alloy gears is in the input and output shafts.
• Ring and pinion sets in automotive differentials are made from steel alloys.
• High-torque devices such as turbines, aerospace gearboxes, and mining equipment use these gears.

Manufacturing process

• For the precise production of gear spurs, tooth and shaping, CNC machining is used.
• The hardness and toughness of the material are maintained through heat treatments such as quenching and carburizing.

·  Stainless Steel Alloy Gears: Corrosion Resistance and Long Lifespan

Automobile gears require stainless steel alloys that have corrosion resistance, durability, and long service life. Chromium content creates a protective layer of oxides, which means that they resist rust, oxidation, and chemical damage (as well), thus the alloys are best suited to moisture-exposed and outdoor car systems. Available heat-treated grades are high-strength, fatigue-resistant, and wear well.

Advantages

• High level of resistance to corrosion and rust.
• Great fatigue strength and life.
• High service life and low maintenance.

Applications

• Gears of the sunroof and window lifts
• Mirror folding mechanisms
• HVAC actuator systems
• EV auxiliary drive systems

Manufacturing

Strength, accuracy, and smooth gear mesh are guaranteed by CNC machining, heat treatment, surface finishing, and precision grinding.

· Engineering Plastic Gears: Noise Reduction and Cost Efficiency

The use of engineering is very common in the automotive industry. Gears for the adjustment systems are manufactured from these materials. Common engineering that could be used in the manufacture of gears is as follows:

• It is a crystalline engineering thermoplastic that could be used in the manufacturing of gears in the molding industry. It has low friction (0.2-0.3) and self-lubricating properties. POM has a (2-3.5%) shrinkage rate and very low moisture absorption (0.2-0.5%).
• It is a semi-crystalline thermoplastic that has high wear and tear resistance. Nylon has a greater moisture absorption capacity, which is around (up to 3% or more).
• The addition of glass fiber and other materials increases the material’s strength.

Advantages

• The main features of engineering plastics are that they are lightweight yet have high strength and wear resistance.
• These plastics have excellent damping resistance, reducing the noise.
• This material remains unaffected by harsh chemicals and moisture.

Application

• POM and nylon gears are common in power-folding side mirrors due to their quiet assembly.
• The seat recline mechanism in the vehicle often uses gears made of engineering plastics.
• The headset and window regulators also have these gears.

Manufacturing

• The method for mass-producing POM and nylon gears is injection molding, which provides precise results.
• For small batches with customization, CNC manufacturing is done using prototypes.

· Aluminum Alloy Gears: Lightweight and Efficiency

Aluminum alloys have been widely used in automotive gears, where lightweight design, corrosion resistance, and aesthetic appearance are demanded. Their natural oxide coating provides strong corrosion resistance, enabling them to be used in vehicle systems for extended periods. Aluminum gears are also economical in weight, as they are low in density, and are suitable for electric vehicles (EVs) and low- to medium-load comfort systems. Their machinability is excellent, yielding to precise and efficient production.

Advantages

• Groundbreaking lightweight construction
• High corrosion resistance
• Excellent machinability
• Good thermal conductivity
• Aesthetic surface finish

Applications

• Seat adjustment mechanisms
• Window regulators
• Comfort and auxiliary systems of EV
• Internally mounted actuator assemblies
• Low-load motor gear systems

Manufacturing

High precision gears are manufactured using CNC milling and turning. Surface finishing and anodizing enhance durability and corrosion resistance, and precision machining provides smooth meshing and silent running.

· Brass Alloys Gears: Smooth Motion and Wear Control

Car gears made of brass alloys are widely used for their high wear resistance, stable friction, and corrosion resistance. Mechanical strength and heat resistance are increased with the addition of zinc, copper, magnesium, and aluminum. Brass offers controlled, smooth friction and is hence ideal for synchronizer rings that allow smooth gear shifting.

Advantages

• Wear and friction resistance are high.
• Very good corrosion resistance.
• Higher thermal and electrical conductivity.
• Smooth gear change and transmission.
• Complex parts are highly machinable.

Applications

• Transmission systems synchronizer rings.
• Valves, cementing fittings, and connectors of the fuel system.
• HVAC control mechanisms
• EV charging interfaces and connectors of high voltage.
• Components of electrical and lighting systems.

Manufacturing

CNC machining of brass gears is done to achieve high dimensional accuracy and geometries. Precision turning, milling, and finishing efforts deliver smooth surfaces, tight tolerances, and stable, long-term performance.

Applications in Vehicle Systems

Automotive gears made of different materials are used in various areas. Some of them are as follows:

· Seat Motor Adjustment Gears

The seat adjustment gears offer multi-directional seat adjustment. They can withstand a weight of up to 300lbs. The gear in the seat allows for a smooth, controlled recline.  

The material used to manufacture the motor adjustment gears in the seat is usually steel or self-lubricating reinforced plastic. These gears are injection-molded, reducing friction and noise. These are cost-effective as well.

The machining precision is required to replace the failed gear parts if they wear easily. High-precision machining can reduce noise and make components more durable.

Usually, the gears in the seat motors are made of engineering plastic, and they suffer some kind of symptoms of failure:

• Stuck at the lowest and the highest recline
• Clicking sound
• The motor runs, but the seat does not move

Honscn manufactures steel and brass gears that can withstand repeated reclining and handling of weight. Their product does not suffer wear and produces noise after some cycles. These brass and steel gears could be used in SUVs and trucks. The motor's service life is extended, offering great durability.

· Window Lift Motor Gears

The gears used in the window lifts require some operational specifications. These gears must support the thousands of up/down cycles. The gear must support intermittent loads, be corrosion-resistant, and maintain precision. The window gears must be noise-controlled during operation.

Using POM gears in window motors is ideal because they are cost-effective and self-lubricating. The noise-reduction requirement for the window lift motor assembly makes POM an ideal material. The more expensive, more durable counterpart is steel-alloy gears, which offer greater resistance and can withstand heavy loads.

· Sunroof Motor Gears

Before installing the kind of gear for the sunroof, it is important to assess the requirements that the material must withstand during the process. The sunroof is exposed to humidity, moisture, and dust. The gear material in the sunroof assembly must be corrosion and wear-resistant.  

The material used in the gear must be engineering plastic or stainless steel. These materials have high corrosion resistance and strength. Nylon is used for the quiet tilting and folding of the sunroof. The high strength and ductility of the steel are also required in the sunroof motor gear.

· Mirror Folding Gears

The frequency of use is quite high, so the gear material must be lightweight and withstand millions of cycles. Nylon and POM are ideal materials because they offer minimal torque and a compact structure. The use of steel, brass, and aluminum gears is common in trucks and SUVs for fatigue and wear resistance.

· Tailgate/Trunk Motor Gears

The gear material used in the trunk must have very high weight and strength resistance. Mostly, the gears used in it are made of a steel alloy that can handle loads of up to many tons. The carbon content in the steel decides the strength and durability of the gears. High carbon steel alloy offers better load management in the gear of a trunk motor. The combination of steel and plastic gear could achieve the same results at a lower cost. Machining precision is required for durability and to prevent spillage.

Selecting the Right Materials and Manufacturing Processes

While selecting the material of the gear to be used in the different motor systems of a vehicle, there are certain factors to be considered before making any decision:

The selection of materials depends on their ability to control torque, manage load, and withstand external environmental conditions. For high load bearing, steel alloy must be used, and for (NVH control) noise control, nylon gears are ideal.

CNC machining is used to manufacture customized gears, while the plastic gears are manufactured by injection molding for bulk orders. Powder metallurgy is used to produce sintered metal alloys for greater precision.

Choosing a CNC supplier for gears is rather difficult. Replacing nylon gears with steel-alloy gears is quite common in the aftermarket. Even slight variations in spur, bore diameter, and tooth size do not mean that the supplier of CNC machining will offer a different product. The purchaser must choose a supplier of high-precision gears with excellent customer service.

Delivering Superior Automotive Components: Honscn

We are 20 years old, and our company provides free material selection consultation to our customers. They will be able to choose materials depending on the torque, load, noise, and cost. We are offering high-quality prototyping for customized gear designs.

Our high-technology gear-machining includes 3- and 5-axis CNC milling/turning with narrow tolerances (+0.005-0.01mm). We guarantee an ideal tooth profile, smooth meshing, and low backlash.

Our quality control is strict, using in-house testing facilities, 100 percent inspection, and certification (ISO, IATF 16949, RoHS). We assure high durability and reliability. We have a consistent material supply chain that helps to avoid delays.

Conclusion

Gears in the automotive industry are essential for power transmission, speed regulation, and the smooth, reliable operation of vehicles. This article brought out the extent to which the choice of material between high-strength steel alloys, brass, lightweight aluminum, and engineering plastics has a direct influence on performance, durability, noise control, and cost. The balance between the load capacity, wear resistance, and environmental tolerance required by each vehicle system is customized. The manufacturing process of the gear is of high quality, including CNC machining, injection molding, and heat treatment, which contribute to the reliability of the gears. For OEMs and aftermarket clients, selecting accurate, customizable, and tested gear solutions is key to ensuring long service life, efficiency, and overall vehicle performance. Visit us on the web https://www.cnchonscn.com/.