Type of Gears - Spur Gear
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Spur gears are simple, cylindrical gears with straight teeth that are parallel to the axis of rotation. They are used to transmit power between parallel shafts, are known for being cost-effective and reliable, and are found in many applications from automotive parts to industrial machinery.
 
Key features and advantages:
  • Simple design: Spur gears are the most basic type of gear, making them easy to manufacture and install.
  • Efficient power transmission: They have high power transmission efficiency, ideal for applications where maintaining power efficiency is important.
  • Constant velocity: They provide a constant velocity ratio, which is beneficial for applications that require a consistent speed.
  • Reliable and durable: Their straightforward design makes them durable and reliable, with few components that can fail.
  • No axial thrust: They do not produce an axial thrust load, meaning the force from the gear does not push along the shaft's axis.
  • Cost-effective: They are often cheaper than other types of gears due to their simpler manufacturing process. 
Disadvantages
  • Noise and vibration: The teeth engage and disengage abruptly, causing significant noise and vibration, particularly at high speeds.
  • Limited load capacity: They are not ideal for heavy loads because the full contact of the teeth creates high impact stress, which can lead to wear and potential tooth breakage.
  • Parallel shafts only: Spur gears can only transmit power between parallel shafts and are not suitable for transmitting power between non-parallel shafts.
  • Limited centre distance: The gears must be positioned so their teeth mesh directly, which limits the distance between their centre points.
  • Stress concentration: The direct engagement of the teeth can lead to stress concentrations at the edges, which can result in fatigue failure.
How they work
  • Spur gears transmit motion when the teeth of one gear mesh with the teeth of another.
  • They are used to transfer power between two shafts that are parallel to each other.
  • The gear with more teeth is called the "gear," while the one with fewer teeth is called the "pinion"
Materials and applications
  • Materials: They are made from various materials, including plastic (like acetal or nylon) and metals (like aluminum, brass, and stainless steel)
  • Applications: They are widely used in industries such as automotive, manufacturing, and consumer electronics.
    Plastic gears: These are lightweight, non-rusting, and can operate without lubrication, making them suitable for food production and medical equipment.
  • Metal gears: These offer greater strength, load-carrying capacity, and heat resistance.