Spur gear and helical gear are two common types of gears in mechanical transmission. They have their own characteristics and advantages. The main differences are reflected in the gear tooth profile, transmission performance and application scenarios.

1. tooth profile

The tooth profile of the spur gear is parallel to the axis, that is, the tooth profile of the gear is straight. The tooth profile of the helical gear forms an angle with the axis, usually 45 degrees or other angles, and the tooth profile is oblique.

2. transmission performance

1. Contact mode: When a spur gear is driving, its tooth surface contact is distributed along a straight line from one end of the gear to the other end. The helical gear is a gradual transition from one end to the other, along the diagonal contact. This makes the helical gear have a higher contact area during transmission, thereby improving the bearing capacity and service life of the gear.

2. Transmission smoothness: Since the tooth surface contact of the helical gear is oblique line distribution, its transmission smoothness is better, suitable for high-speed and heavy-duty occasions. The spur gear is prone to impact and noise during transmission, and is suitable for low-speed or medium-speed transmission.

3. Overlap coefficient: The large overlap coefficient of helical gears means that there are more teeth involved in the transmission at the same time, which is beneficial to improve the stability and load distribution of the transmission. The overlap coefficient of the spur gear is small, and the number of teeth involved in the transmission is relatively small.

3. Application Scenarios

Because of its simple structure and convenient manufacture, spur gears are widely used in some occasions that do not require high transmission, such as ordinary machinery and equipment, household appliances, etc.

Helical gears are suitable for occasions that require high transmission performance, such as automobiles, machine tools, ships and other heavy equipment. Helical gears can transmit large torques and perform well under high-speed and heavy-duty conditions.

4. other differences

In addition to the above main differences, there are also differences between spur gears and helical gears in terms of manufacturing difficulty, cost, and meshing efficiency. Generally speaking, the manufacturing difficulty and cost of helical gear is slightly higher than that of spur gear, but its transmission performance is superior, which makes it irreplaceable in some occasions.

In short, spur gears and helical gears have their own characteristics and advantages, and the appropriate gear type should be selected according to actual needs in the application. Spur gears are suitable for some occasions that do not require high transmission performance, while helical gears are suitable for heavy equipment that require high transmission performance. Understanding the difference between the two helps to better select and use these two gears to improve the performance and efficiency of mechanical equipment.