What is a spur gear?

Spur gears will be the most easily visualized common gears that transmit movement between two parallel shafts. Because of the shape, they are categorized as a type of cylindrical gears. Because the tooth surfaces of the gears are parallel to the axes of the installed shafts, there is no thrust force generated in the axial path. Also, because of the simple production, these gears can be made to a high degree of precision. However, spur gears possess a disadvantage in that they very easily make noise. Generally speaking, when two spur gears are in mesh, the gear with more the teeth is named the “gear” and the one with the smaller number of tooth is named the “pinion”.

The unit to point the sizes of spur gears is often stated, as specified by ISO, to be “module”. In recent years, it is usual to set the pressure angle to 20 degrees. In commercial machinery, it is most common to employ a part of an involute curve as the tooth profile.

Even though not limited by spur gears, profile shifted gears are utilized when it is required to adjust the center distance slightly or to strengthen the gear teeth. They are produced by adjusting the range between your gear cutting device called the hobbing tool and the gear in the production stage. When the change is positive, the bending strength of the gear increases, while a negative shift slightly reduces the center distance. The backlash may be the play between the the teeth when two gears are meshed and is needed for the soft rotation of gears. When the backlash can be too large, it leads to improved vibration and noise while the backlash that’s too small leads to tooth failing due to the lack of greenhouse motor lubrication.

All KHK spur gears have an involute tooth shape. Put simply, they are involute gears using part of the involute curve as their tooth forms. Searching generally, the involute shape may be the most wide-spread equipment tooth form because of, among other factors, the ability to absorb small center distance errors, very easily made production equipment simplify manufacturing, heavy roots of the teeth make it strong, etc. Tooth form is often referred to as a specification in drawing of a spur gear as indicated by the height of teeth. Furthermore to standard full depth teeth, prolonged addendum and stub tooth profiles exist.


China Coupling Co., Ltd.

Mail: [email protected]

As one of leading Couplings manufacturers, suppliers and exporters of mechanical products, We offer Coupling and many other products.
Please contact us for details.

Recent Posts