Spur gears are one of the most important aspects of mechanical design and mechanical engineering. A good engineer must know all the aspects of spur gears. Here, we give very important information about spur gears that are provided by Mechanical Base.
Important Points About Spur Gears
- Torque and speed relations in gear systems: First of all, it is the most important parameter for power transmission in machinery via gear sets. If the driving gear is bigger than the driven gear, the torque at the output shaft is reduced, but rotational speed increased. The same thing is valid for other situations.
- Types of spur gears and involute gear tooth form: Types of spur gears change according to the purpose and constructional parameters of mechanical application. Involute design of gear teeth is used to reduce mechanical problems of gear meshing.
- Pitch and metric module of spur gears: In gear pairs or gear systems, the pitches or metric modules of gears must be the same. You can find pitches and metric modules of gear standards if you are selecting gears for your mechanical application. Pitch of gear is a standard set of gears in US Customary and the metric module is the standard sets of spur gears in SI units. These two values can be converted to each other. Gear manufacturers produce gears in standard pitch and metric module values.
- Teeth geometry on spur gears: Meshing of gear pairs is not an easy thing. For proper working of gear pairs, some parameters must be calculated and assessed for gear pairs. You can use geometrical calculators for the calculations.
- Contact ratio calculation for spur gear pairs: Spur gear manufacturers recommend a contact ratio of 1.2 minimum between spur gear sets. In general applications, the contact ratio of spur gear pairs is generally around 1.5.
- Preventing interference in spur gear design: Interference is a very important problem that must be solved by the designer in the design stage of gear systems. Interference is a mechanical problem between mating gear teeth during working. With some design considerations, the interference problem can be eliminated. Also, if a gear system has an interference problem, this can be solved with the application of ‘undercutting’ on gear teeth.
- Velocity ratio calculation for spur gear mates: Velocity ratio is also a very important beginning parameter that must be calculated before starting gear system design. It is the ratio of driven gear’s teeth number to driving gear teeth number.
- Gear trains and train value calculations: Gear trains are commonly used gear system that includes a bunch of gear mates in a one gear system. The velocity ratio of all the gear pairs inside gear trains is the training value of the gear train system. If you multiply input torque with train value, you can find the output torque of all gear train systems.
- Use of idler gears in spur gear systems: Like other parameters, the direction of rotation of a shaft is an important thing. If there is an uncompromising situation with the turning rotations of gears, idler gears are generally used to change the turning direction of the driven gear. Idler gears are also used for transfer gears when the two shafts are distant.
- Use of internal spur gear systems: In internal spur gear systems, the driven gear has teeth not outside of the gear body, inside of the gear body. And pinion is placed inside the internal gear. Internal gear systems are also used to save space and also used when the rotation direction of driven and driving gear must be the same.
- Rack and pinion gear systems and rack velocity: Rack and pinion systems are also very important to spur gear systems that are generally used in steering systems of automobiles and sliders of doors or types of machinery. The rack is a straight gear that is mated with pinions. Rack velocity must be calculated by using the pitch diameter of the pinion to obtain a precise value.
Conclusion About Spur Gear Systems
These contents above in Mechanical Base include precious information about spur gear systems at the engineering level. And you can find out specific information related to spur gears by using this guide.
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