Gears are used in a large number of mechanical equipment. They perform several important jobs, but most importantly, they provide gear reduction for motorized equipment. This is key, because as is often the case, small motors that rotate very quickly can provide enough power to the device, but not enough torque. The article mainly introduces the functions of gears and what are the important parameters.

For example, the gear deceleration of an electric screwdriver is very large because it requires a lot of torque to turn the screws, but the motor only produces a small amount of torque at high speeds. By gear reduction, it is possible to increase torque and reduce output speed at the same time.

Another thing the gears do is adjust the direction of rotation. For example, in a differential between the rear wheels of a car, power is transmitted through an axle running along the center of the car, and the differential must rotate power 90 degrees to apply it to the wheels.

The function of the gear
Gears are often used to transfer rotary motion between mechanical shafts. When different types and sizes of gears are combined, the speed and direction of the rotation axis can be changed to change the rotational motion into linear motion.

Since there are many different types of gears, our common gears have spur gears. The spur gear is mainly divided into two types: external spur gear and internal spur gear, external spur gear may be commonly used and simpler gear system, external spur gear is a cylindrical gear with straight teeth parallel to the axis. They are used to transfer rotational motion between parallel axes, which rotate in opposite directions. When the surfaces of two gears are in contact at the same time, they tend to produce noise at high speeds.

Internal spur gear: Internal spur gear works similarly to external spur gear, except that the pinion is located inside the spur gear. They are used to transfer rotational motion between parallel axes, but in this arrangement, the axes rotate in the same direction. The internal spur gear of the internal spur gear works similarly to the external spur gear, except that the pinion is the inside of the spur gear. They are used to transfer rotational motion between parallel axes, but in this arrangement, the axes rotate in the same direction.

What are the important parameters of gears
Several important parameters of the gear: modulus, indexing circle, pressure angle and parameter parameters. Modulus is a very important parameter in gear transmission. The size of the gear tooth is defined by the modulus. The symbols m (modulus) and the number (mm) indicate that the smaller the tooth size, the smaller the modulus, and the larger the tooth size, the larger the modulus. The modulus is multiplied by PI to get the pitch (p), which is the length between two adjacent teeth. Formula: p = PI x modulus = πm

Indexing circle: The indexing circle is a dimensional reference chosen to facilitate gear design and manufacturing. The gear index circle has a standard module and a standard pressure angle, which is generally used as the basis for calculation. The circumference of the gear index circle = Td = zp.

Pressure angle: The pressure angle is the angle at which the tooth is tilted relative to the normal of the joint. The pressure angle is generally 20°. However, pressure angles of 14.5° or 17.5° are sometimes used. The greater the pressure angle, the wider the tooth root and the higher the strength. The angle between the radius line and the tangent line of the tooth profile. The pressure angle (α) is generally 20°. Modulus (m), pressure angle (α) and number of teeth (z) are the three basic parameters of a gear.

Number of teeth: The important parameters of the gear are also the number of teeth, it is necessary to determine the number of teeth of a pair of meshing gears to calculate the speed ratio, pay attention to the minimum number of teeth (except worms). The number of teeth in the pinion needs to be minimized to expand the deceleration or increase the ratio. However, the tip of a rack tool may overlap the tooth root, and if the number of teeth falls below a certain value, the tip may measure the tooth root.

The article mainly introduces the functions of gears and what are the important parameters, and you can understand that gears are usually used to transmit rotational motion between mechanical shafts. When different types and sizes of gears are combined, the speed and direction of the rotation axis can be changed to change the rotational motion into linear motion. In addition, several important parameters of the gear can be known: modulus, indexing circle, pressure angle, number of teeth, etc.