How to choose the model of the reducer? How to choose a reducer?

Try to choose a gear ratio that is close to the ideal:

Reduction ratio=servo motor speed/reducer output shaft speed

Torque calculation: For the lifespan of the gearbox, torque calculation is very important, and attention should be paid to the maximum torque value (TP) of acceleration, whether it exceeds the maximum load torque of the gearbox.

The applicable power is usually the applicable power of servo models on the market. The applicability of reducers is very high, and the working coefficient can be maintained above 1.2. However, the selection can also be determined according to one's own needs:

There are two key points:

1. The output shaft diameter of the selected servo motor cannot be greater than the maximum used shaft diameter on the table;

2. If the torque calculation work is carried out, the speed can meet the normal operation, but when there is insufficient phenomenon when the servo is fully output, it is necessary to perform current limiting control on the driver on the motor side or torque protection on the mechanical shaft.

The selection of a universal reducer includes steps such as proposing original conditions, selecting types, and determining specifications.

In contrast, the type selection is relatively simple, and accurately providing the working conditions of the reducer and mastering the design, manufacturing, and usage characteristics of the reducer are the key to correctly and reasonably selecting specifications for universal reducers.

The selection of specifications should meet the conditions of strength, thermal balance, and radial load bearing on the shaft extension part.

Select specifications:

The biggest difference between the design and selection methods of universal reducers and specialized reducers is that the former is applicable to various industries, but the reducer can only be designed according to a specific operating condition. Therefore, when selecting, users need to consider different correction factors based on their own requirements. Factories should choose the actual motor power (not the rated power of the reducer) according to their actual requirements; The latter is designed according to the specific conditions of the user, and the coefficients to be considered are generally taken into account during design. When selecting, it is relatively simple to ensure that the power used is less than or equal to the rated power of the reducer.

The rated power of a universal reducer is generally determined based on the use (working condition) coefficient KA=1 (the electric motor or steam turbine is the prime mover, the working load is stable, the working time is 3-10 hours per day, the number of starts per hour is ≤ 5, and the allowable starting torque is twice the working torque), the contact strength safety coefficient SH ≈ 1, the failure probability of a single pair of gears ≈ 1%, and other conditions.

The rated power of the selected reducer should meet

PC=P2KAKSKR ≤ PN

In the formula, PC - calculated power (KW);

PN - Rated power of the reducer (KW);

P2- Working machine power (KW);

KA - coefficient of use, considering the impact of operating conditions;

KS - Starting coefficient, considering the influence of starting times;

KR - Reliability coefficient, considering different reliability requirements.

The usage coefficients used by countries around the world are basically the same. Although many samples do not reflect the two coefficients of KSKR, due to knowing oneself (having clear requirements for its own operating conditions) and knowing others (having clear performance characteristics of reducers), foreign selection generally leaves a large margin, which is equivalent to considering the influence of KRKS.

Due to different usage scenarios, varying degrees of importance, varying degrees of damage to personal safety and production, and varying degrees of difficulty in maintenance, the requirements for the reliability of reducers are also different. The coefficient KR is the actual required reliability to modify the reliability of the original design. It complies with the provisions of ISO6336, GB3480, and AGMA2001-B88 (American Gear Manufacturers Association Standard) for gear strength calculation methods. Some domestic users do not yet have specific requirements for the reliability of reducers. They can follow the design regulations for general specialized reducers (SH ≥ 1.25, failure probability ≤ 1/1000), and for more important fields, KR=1.25=1.56.

Thermal balance verification:

The allowable thermal power value of a universal reducer is determined based on the maximum allowable equilibrium temperature of the lubricating oil (usually 85 ℃) under specific operating conditions (generally 20 ℃, 100% per hour, continuous operation, and 100% power utilization).

When the conditions are different, correction shall be made according to the corresponding coefficient (sometimes combined into a single coefficient).

The selected reducer should meet the requirements of

PCt=P2KTKWKP ≤ Pt

In the formula, PCt - calculated thermal power (KW);

KT - Environmental temperature coefficient;

KW - operating cycle coefficient;

KP - Power utilization coefficient;

Pt - allowable thermal power of the reducer (KW).

Check the load of the shaft:

Universal reducers often require limitations on the maximum radial load allowed to be borne by the input and output shafts in the middle, which should be verified. If exceeded, requirements such as thicker shaft diameters and larger bearings should be proposed to the manufacturer.

Lubrication maintenance

Before putting into operation, install the recommended model and value of lubricating grease into the gearbox. The gearbox is lubricated with lubricating oil. For vertically installed reducers, considering that lubricating oil may not guarantee reliable lubrication of the top bearing, additional lubrication measures are adopted.

Before operation, inject an appropriate amount of lubricating oil into the gearbox. Gearboxes are usually equipped with oil injection holes and oil drain plugs. Therefore, the installation position must be specified when ordering the gearbox.

The working oil temperature should not exceed 80 ℃.

The combination gearbox with lifelong lubrication is filled with synthetic oil at the manufacturing factory. In addition, the gearbox is usually supplied without lubricating oil and with oil filling and oil drain plugs. The quantity of gearbox lubricating oil listed in this sample is only an estimated value. Set the position of the oil level plug according to the installation position specified during the order to ensure correct oil injection. The oil injection amount of the gearbox should be determined according to different installation methods. If the transmission power exceeds the thermal capacity of the gearbox, an external cooling device must be provided.