Planetary gear transmission in scraper chain conveyors

The gear unit was designed for planetary gearing. Compared with cylindrical bevel gear reducer, it is small in size, light in weight and high in efficiency.
The scraper transporter is a common face transporting machine used in the coal industry. The scraper transporter reducer in China is almost always driven by a conical cylindrical three-stage gear, and there are few planetary gears. Planetary gear transmission is a moving shaft transmission. It uses several planetary gears to transmit power. It uses reasonable internal meshing to divert power. It is small in size, light in weight, large in carrying capacity, stable in operation, low in noise, high in efficiency, long in life and high in reliability. . The coal industry has been widely used in drum type coal mining machines, roadway boring machines, belt conveyors, mining hoists and mining small winches, and has achieved good economic and social benefits. Practice has proved that the use of planetary gear transmission can not only reduce manufacturing costs and operating costs, but also mature and reliable technology.
1 Planetary Gear Reducer Arrangement The scraper conveyor reducer is arranged in three types: parallel, vertical and hybrid, that is, the axis of the reducer is parallel to the conveyor body, vertical or both. For small and medium-sized scraper transporters using planetary gears, the reducers should be arranged in a parallel arrangement. The advantage is that the width of the head is small and the empty top distance is small to facilitate the management of the top plate. The type of reducer assembly is as shown. The reducer adopts two-stage gear transmission, the first stage adopts the bevel gear transmission, and the second stage adopts the 2H-K type planetary gear negative number transmission. The gear unit with a single unit power below 75 kW is assembled as shown in (a), and the chain tensioner is installed at the shaft end; the gear unit of the single unit with a power of 90 kW or more is assembled as shown in (b) on its I axis. Install the chain tensioner. The shaft end form of the reducer is selected according to the assembly requirements.
For heavy-duty scraper conveyors with planetary gears, the gearboxes should be vertically arranged, and the two-stage gears are driven by 2H-K planetary gears. This eliminates the bevel gear transmission with relatively weak bearing capacity, reduces the circumferential dimension of the reducer, and increases the size of the vertical direction of the machine head. The reducer adopts the assembly type as shown in (c) and is mounted on its I axis. Tight chain device.
2The application of planetary gear reducer on scraper conveyor With the implementation of the coal industry's production efficiency strategy, most of the transport capacity has reached 1500~3000t/h, and the installed power has reached 2X(375~525)kW. The 750kW scraper conveyor motor has been introduced, so it is imperative to use a planetary gear transmission reducer for the scraper transporter. In the southern mines of China, due to the small size of the wells, most of them use small scraper transporters. The installation, disassembly and handling are basically done manually. The labor intensity of the workers is very high, and because the working face is small, it brings extremes to the overhaul. Great inconvenience, therefore, it is necessary to reduce the weight of the reducer and improve the reliability of the reducer. For a reducer with a motor power of less than 40 kW, the hydraulic coupler should not be used between the motor and the reducer. Therefore, a mechanical overload protection device must be installed. To protect the motor and reducer. The conventional reducer passes through a hollow shaft in the fourth shaft, and uses a twist-back drive to install a mechanical break-off protection device, making the four-axis shaft system very complicated. In the planetary gear transmission reducer, a mechanical break pin protection device can be installed between the inner ring gear and the casing. When the gear is normally driven, the power is output through the planetary gear bar. Once the machine is seriously overloaded, the inner ring gear and the casing are cut and installed. The safety pin between the two, at this time, the inner ring gear rotates, the planetary wheel rotates without revolving, thereby achieving the purpose of overload protection. This type of reducer can be floated in a floating manner. For gear units with motor power above 40 kW, since there is no need to set up a mechanical protection type 22 scraper conveyor reducer transmission system to protect the device, the floating mode of the sun gear and the planetary wheel can be used at the same time.
/22 type scraper conveyor. For the modified design of the scraper conveyor, a planetary gear reducer is used instead of the conventional conical cylindrical gear reducer, and the transmission system is as shown. The total gear ratio of the reducer is 21.88, the first stage is 3.928, the second stage is 5.57, the mechanical efficiency is 0.943, and the weight is about 2 650N. The original conical cylindrical gear reducer has a total transmission ratio of 22.24 and a mechanical efficiency of 0.867. The weight is about 4700N. It can be seen that the planetary gear transmission reducer is light in weight, small in size, high in transmission efficiency and low in power consumption. The size and weight of the reducer are reduced, and the strength and life of the gear can be improved by chemical treatments such as high-quality materials and hardened surfaces, thereby improving the reliability of the reducer. 3 Conclusion The planetary gear transmission technology is mature and reliable. It can be used on the scraper conveyor to not only reduce the weight of the reducer, but also improve the reliability and service life and reduce the labor intensity of the user. Therefore, replacing the traditional conical cylindrical gear reducer with a planetary gear transmission reducer will bring obvious economic and social benefits.