Reducer in mechanical design


Reducer The reducer is an independent closed transmissi […]

The reducer is an independent closed transmission device between the prime mover and the working machine, which is used to reduce the speed and increase the torque to meet the work needs. The reducer has a compact structure, high efficiency, accurate and reliable transmission motion, easy use and maintenance, and can be produced in batches, so it is widely used.
The working principle of the reducer
The reducer is generally used in low-speed and high-torque transmission equipment. The motor, internal combustion engine or other high-speed running power is passed through the gear with a small number of teeth on the input shaft of the reducer to mesh with the large gear on the output shaft to achieve the purpose of deceleration. The reducer will also have several pairs of gears with the same principle to achieve the desired reduction effect. The ratio of the number of teeth of the large and small gears is the transmission ratio.
The basic structure of the reducer:
The reducer is mainly composed of transmission parts (gears or worms), shafts, bearings, boxes and accessories. Its basic structure has three parts: (1) gear, shaft and bearing combination; (2) box body; (3) reducer accessories;
Gear, shaft and bearing combination The pinion gear is made into one piece with the shaft, called the gear shaft. This structure is used when the diameter of the gear is not related to the diameter of the shaft. If the diameter of the shaft is d, the diameter of the gear root circle is df, when df-d ≤ 6 ~ 7mn, this structure should be used. When df-d>6~7mn, the gear and shaft are separated into two parts, such as a low-speed shaft and a large gear. At this time, the gear is connected with the circumferential fixed flat key of the shaft, and the parts on the shaft are axially fixed by the shaft shoulder, the sleeve and the bearing cover. The box is an important component of the reducer. It is the base of the transmission parts and should have sufficient strength and rigidity. The box body is usually made of gray cast iron. For heavy-duty or shock-loaded reducers, a cast steel box can also be used. Reducer accessories
In order to ensure the normal operation of the reducer, in addition to giving enough attention to the structural design of gears, shafts, bearing combinations and casings, consideration should also be given to filling, draining, checking the oil level, processing and Reasonable selection and design of auxiliary parts and components such as precise positioning and lifting of box cover and box seat during disassembly and maintenance.
The box of most reducers is made of medium-strength cast iron, and the heavy-duty reducers are made of high-strength cast iron and cast steel. When a single piece is produced in small quantities, it can also be welded with steel plates. The shape of the reducer box requires a simple shape and a flat surface. In order to facilitate installation, the box body is often made into a split type, and the split surface often coincides with the axis plane.
Reducer assembly general steps
Mounting base → input shaft shaft assembly → intermediate shaft shaft assembly → output shaft shaft assembly → install each shaft → mesh rotation → upper cover assembly → upper cover assembly → bolt assembly → end cover assembly

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