What Is a Spur Gear?
A spur gear is a type of gear with a cylindrical tooth trace that is straight and parallel to the shaft. A spur gear can be used for a wide range of applications, from light to heavy loads and from low to high speeds, depending on the design. Because they are relatively easy to machine, spur gears are the most commonly used of all types of gears.
Spur gears have many options in terms of material (metal or resin), processing method (machining, molding, or sintering), and lubrication (type and availability of lubricant). Therefore, they must be selected appropriately for each application.
Uses of Spur Gears
Spur gears are versatile and are one of the most widely used machine elements. They are used in a wide range of fields due to their large drive transmission force, freely selectable speed of rotation, and the convenience of being able to change the direction of rotation and having a large drive transmission force.
Spur gears are used in a wide variety of applications, including drive transmission parts for toy cars, drive transmission parts inside clocks and watches, drive transmission parts for various printers, drive transmission parts for industrial robots, and drive transmission applications for power tools and agricultural machinery.
Principle of Spur Gears
Spur gears transmit motion to other parts of a gear by meshing the teeth one after another. Because the teeth of spur gears are cut parallel to the direction of the shaft, theoretically no axial force (thrust load) is generated, which leads to a reduction in equipment size and simplification of the overall structure.
With a pair of meshing spur gears, the direction of rotation is opposite, the number of rotations is inversely proportional to the number of teeth, and the torque is also proportional to the number of teeth. These drive transmission theories do not depend on tooth size, so it is possible to think in the same way from small power to large power.
When spur gears are used for large power portions, it is common to use metal as the material and lubricate the meshing area. Without lubricant, the gears will wear out in an extremely short time. Its hardness can be increased by hardening the surface of the metal material, thereby extending the life of the gears.
When spur gears are used for medium to low-load areas, the resin can be used as a material. In addition, in the case of resin, it is easier to obtain cost benefits by molding and manufacturing gears.