Many industry practitioners only compare the power to match the reducer model, and are confused when faced with the complicated reduction ratio, rated torque, allowable torque, shaft diameter and other parameters in the manufacturer"s sample. As everyone knows, the hoist is an alternating impact load device, and the single power matching error is extremely large, which is also the core cause of tooth chipping, shaft breakage, and overload burnout of the reducer.
Putting aside complicated professional terminology, combined with the specific working conditions of the elevator, the meaning, value standards and model naming rules of the four core parameters are easily understood and the suitable models are accurately screened through the parameters.
1. Model naming parameters: understand the model and quickly lock the model attributes
There are unified rules for the model coding of hoist reducers on the market. Take the high-frequency ZSY355-28-2S and NBD450-20 as examples to teach you how to quickly decode:
1. ZSY355-28-2S: ZSY represents the three-stage hard tooth surface cylindrical gear reducer; 355 refers to the low-speed gear center distance (mm), the larger the value, the stronger the load; 28 is the nominal reduction ratio; 2S represents the double-output shaft installation form;
2. NBD450-20: NBD is a special hard tooth surface model for new heavy-duty hoists; 450 is the base specification; 20 corresponds to the equipment reduction ratio; this model has optimized box structure and has better impact resistance than the traditional ZSY series.
In addition, the number at the end of the K series model represents the base size, and the BLD number represents the base number. The base number is the basis of Selection, which directly determines the volume and load capacity of the reducer.
2. Reduction ratio: the key to controlling the lifting speed of the elevator
In layman"s terms, the reduction ratio is the ratio of the input speed to the output speed, which directly determines the lifting speed of the elevator hopper, and at the same time affects the output torque in reverse: the larger the reduction ratio, the lower the output speed, the greater the torque, and the stronger the ability to withstand heavy loads.
Based on practical experience in the industry, we will provide you with clear adaptation values:
1. Light grain elevator: suitable reduction ratio 10-30, fast hopper lifting speed and high lifting efficiency;
2. Medium-sized sand and gravel elevator: suitable reduction ratio 30-60, taking into account efficiency and load stability;
3. Heavy-duty ore hoist: suitable reduction ratio 60-80, low speed and high torque, buffering material impact.
Important reminder: It is strictly forbidden to use a model with a too small speed ratio for the hoist. Excessive speed will aggravate the start-stop impact and greatly increase the probability of gear damage.
3. Rated torque & allowable torque: impact resistance Selection core parameters
These are the two parameters that are most easily confused, and they are also the top priority of the hoist Selection. They have different divisions of labor and one is indispensable:
1. Rated torque: refers to the standard torque that the reducer can continuously carry for a long time, adapting to the smooth operating state of the elevator. Selection Bottom line: rated torque > the normal operating torque of the equipment;
2. Allowable impact torque: the instantaneous limit torque that can be withstood in a short period of time, corresponding to impact conditions such as material jamming, heavy load starting, and emergency braking of the elevator. Industry rigid standards: Under hoist operating conditions, the allowable torque must be more than 1.8 times the normal load torque, and it must be 2.5 times under super-heavy duty conditions.
Taking the NBD450 model as an example, its rated torque is 26,000N·m, and its allowable peak torque can reach 65,000N·m. It has sufficient torque redundancy and is suitable for the extreme impact conditions of large mining hoists.
4. Shaft diameter and installation parameters: avoid installation and adaptation failures
After the parameters are matched, the basic installation parameters must be verified. Many equipment failures are caused by shaft diameter mismatch and installation form conflicts:
1. Input/output shaft diameter: It needs to be accurately matched with the motor shaft and elevator main shaft, and the error shall not exceed ±0.5mm. If the shaft diameter is too small, it will easily cause shaft breakage, and if it is too large, it cannot be assembled. The output shaft of heavy-duty models generally adopts an integrated forging process, and the hollow shaft aperture covers 50-200mm;
2. Installation form: The horizontal model of the elevator is suitable for most bucket elevators; the vertical model is suitable for small loaders; the side-mounted model is specially designed for chain elevators with limited space. Do not mix installation modes.
