Many customers may have engineers who are familiar with their professional machinery and have great prestige, but there are many shortcomings in the selection of reducers in Shanghai. Many are selected according to the most ambitious books and there may be no unexpected conditions. The time when the machine was used did not meet its own expectations, so let me talk about how to choose the type of reducer that suits me.
Try to choose a reduction ratio close to ambition:
Reduction ratio = motor speed / reducer output shaft speed
Torque calculation: Torque calculation is very important for the life of the reducer.
And pay attention to the maximum torque value (TP) of the acceleration, whether it exceeds the maximum load torque of the reducer.
The applicable power is generally the applicable power of the servo reducer models on the market. The adaptability of the reducer is very high, and the operating coefficient can be maintained above 1.2, but the selection can also be decided according to your own needs:
There are two main points:
1. The output shaft diameter of the selected servo motor cannot be greater than the maximum application shaft diameter on the table;
2. If the rotation speed can be satisfied with the normal operation through the torque calculation operation, but when the servo output is full, if there is a lack of phenomenon, you can do current limiting control on the motor side driver or torque protection on the mechanical shaft. This is It is necessary.
The selection of general reducer includes the process of proposing original conditions, selecting types, and recognizing specifications.
In contrast, the type selection is relatively simple, and accurately supplying the working conditions of the reducer, grasping the characteristics of the reducer's planning, production and operation is the key to the correct and reasonable selection specifications of the general reducer.
The selection of specifications should satisfy the conditions of strength, thermal balance, and radial load on the shaft extension.
The biggest difference between the general and special reducer planning and selection methods is that the former is suitable for all occupations,
However, the deceleration can only be planned according to a specific working condition, so the user needs to consider different correction factors according to their respective requirements when selecting, and the factory should nameplate the motor power (not the rated power of the reducer) selected in practice; the latter According to the user's special conditions, the coefficient of consideration is generally considered in planning. When selecting, you only need to use the power less than or equal to the rated power of the reducer. The method is relatively simple.
The rated power of the universal reducer is generally based on the application (working condition) coefficient KA = 1 (the motor or steam turbine is the prime mover, the load of the working machine is stable, the daily operation is 3 ~ 10h, the recommended number of times per hour is ≤5 times, and the allowable recommended torque is (2 times the working torque), the safety factor of the touch strength SH≈1, the failure probability of the single-pair gear ≈1%, and other conditions are accepted.
The rated power of the selected reducer should be satisfactory
PC = P2KAKSKR≤PN
In the formula PC-accounting power (KW);
PN-the rated power of the reducer (KW);
P2——Working machine power (KW);
KA——Use coefficient, consider the influence of application conditions;
KS——Recommended coefficient, considering the influence of the recommended frequency;
KR——Reliability coefficient, considering different reliability requirements.
The application coefficients used by countries all over the world are basically the same. Although many samples do not reflect the two coefficients KS \ KR,
However, due to confidant (clear requirements on their own working conditions) and confidant (clear on the function and characteristics of the reducer), foreign models generally have a large amount of surplus when selecting models, which is equivalent to considering the impact of KR \ KS.
Due to different application occasions, different degrees of importance, different sizes of personal safety and production loss after damage, and different repair difficulty, the requirements for the reliability of the reducer are also different. The coefficient KR is the reliability required by practice to modify the reliability of the original plan. It conforms to the regulations of ISO6336, GB3480 and AGMA2001-B88 (American Gear Manufacturers Association Specification) on the gear strength calculation method. Some domestic users have not put forward specific requirements on the reliability of the reducer. They can follow the planning rules of the general special reducer (SH≥1.25, failure probability≤1 / 1000), and take KR = 1.25 = 1.56 on more important occasions .
Thermal balance check:
The allowable thermal power value of the universal reducer is under the specific working conditions (general ambient temperature 20 ℃, 100% per hour, continuous operation, power utilization rate 100%), according to the maximum equilibrium temperature of the lubricant (generally 85 ℃) admitted. Different conditions
It is corrected according to the corresponding coefficient (sometimes combined into a coefficient).
The selected reducer should be satisfactory
PCt = P2KTKWKP≤Pt
In the formula PCt——Accounted thermal power (KW);
KT——Ambient temperature coefficient;
KW-operating cycle coefficient;
KP——Power utilization factor;
Pt——Allowable thermal power of reducer (KW).
Check the load of the shaft:
Universal reducers often have to restrict the maximum radial load that can be accepted in the center of the shaft extension of the input shaft and output shaft, and should be checked. When exceeding, the manufacturer should be requested to increase the shaft diameter and increase the bearing.