Gears coupling: an analysis of materials and their combinations

Main types of materials used in gears

• Steel: It is one of the most common materials for gears due to its high strength and durability. It can withstand heavy loads and high temperatures without significantly deforming. However, steel is heavier than other materials and can be subject to corrosion if not treated properly.
• Plastic (polymers): offers light weight, corrosion resistance, reduced gear operating noise and low friction. They are less subject to wear than metals. However, plastics can be less resistant and durable than metals, especially under high load conditions or extreme temperatures.
• Bronze: It is often chosen for its good wear resistance, low friction and corrosion resistance. It is particularly suitable for applications requiring good strength and durability. However, bronze is less durable than steel and may require lubrication to avoid excessive friction.
• Aluminium: It is known for its light weight, good thermal conductivity and corrosion resistance. It is often used when weight is a critical factor. However, aluminum is generally less mechanically strong than steel and can deform under high loads.
• Cast iron: offers high resistance to wear and deformation, together with good vibration absorbing properties. It is particularly suitable for high load and high strength applications. However, cast iron is more brittle than steel and can be prone to fracture under sudden loads.

Role of the material in the main characteristics required of gears

• Strength and durability: Steel is preferred for high-load applications, while plastics are used to reduce weight and noise.
• Reduced wear: Materials such as bronze are chosen for their ability to resist wear and maintain performance over time.
• Noise reduction: Plastics reduce gear operating noise, improving user comfort.
• Corrosion resistance: Aluminum and bronze are preferred in corrosive environments due to their corrosion resistance.

Frequent couplings of different materials: opportunities and disadvantages

• Steel-Plastic: This combination offers a combination of the strength of steel with the lightness and noise reduction of plastic. It is particularly useful in applications where weight reduction is critical, such as in the automotive industry. However, you need to pay attention to wear and tear, as plastic may not be able to withstand heavy loads or high-temperature applications. Additionally, there may be challenges in terms of thermal compatibility between the two materials, which could cause adhesion or warping issues.
• Steel-Bronze: This pairing offers a combination of the wear resistance of steel with the self-lubricating, low-friction properties of bronze. It is often used in heavy industrial applications, such as in the marine industry and mechanical engineering. However, it requires lubrication to maintain proper operation and avoid premature wear. This can add cost and complexity to system maintenance. Furthermore, it is important to consider the chemical compatibility of the lubricant with both materials to avoid corrosion problems.
• Plastic-Plastic: This coupling offers a significant reduction in weight and noise compared to other heavier materials such as steel. It is commonly used in applications where weight reduction and silence are priorities, such as in electronic devices and the food industry. However, plastic materials can have limitations in terms of strength and durability, especially under heavy loads or in extreme environmental conditions. This may require a more robust design or the addition of structural reinforcements, potentially increasing manufacturing costs.