Many non professional demanders usually demand that the smaller the size, the greater the torque, the lower the noise, and the cheaper the price when selecting DC motors . In fact, this selection not only increases the cost of the product, but also prevents the selection of a suitable model. Based on the experience of experienced engineers in the industry, it is recommended to select from the following aspects:

1： Mechanical dimensions

1. The maximum acceptable installation space, such as diameter, length, etc.

2. The size and installation position of the screws, such as their specifications, effective depth, spacing, etc.

3. The diameter of the product output shaft, flat screws, pin holes, positioning plates, and other dimensions should be considered for installation matching first.

In product design, try to reserve a larger product assembly space and have more models to choose from.

2： Selection of electrical performance

1. Determine the rated torque and speed. If you don't know what you need, you can estimate and buy a ready-made one in the market for testing. Once it's OK, send it to the supplier for testing and confirmation. At this time, you only need to provide the power on voltage and working current.

2. Maximum allowable current and torque. Usually, it is believed that the greater the torque, the better. In fact, excessive torque can cause damage to the entire equipment system, causing mechanical and structural wear, as well as damage to the DC motor and gearbox itself and insufficient lifespan.

3. When selecting electrical performance, try to choose low speed and small reduction ratio as much as possible, in order to obtain a high strength and long service life product.

3： Selection of noise

Usually, the noise referred to refers to mechanical noise

1. After installing the motor into the product, it was found that the noise was quite loud. It is necessary to improve the noise. Repeated sample sending still cannot solve the problem, which often occurs. In fact, this kind of noise may not necessarily be the noise emitted by the product itself, but may be caused by various noises, such as resonance caused by too fast rotation speed, resonance formed by direct rigid cooperation between the gearbox and mechanical equipment, or noise caused by eccentricity of the dragging load.

2. In addition, the selection of the product itself also requires strong technical support. Generally, choosing plastic gears has lower noise than metal gears, and choosing helical gears has lower noise than straight gears. Metal worm structures and planetary gearboxes have higher noise. Of course, optimizing design and ensuring machining accuracy can also effectively reduce noise.

4： Determine the priority direction for product assurance

1. Select different reduction motors based on different usage environments. For example, financial machinery requires product reliability, such as toys, safety and environmental protection. For industrial products such as valves, priority should be given to product lifespan, while for household products, priority should be given to product silence.

2. Usually, experienced engineers will tailor detailed products that meet customer requirements based on different customer requirements, rather than just meeting the rotational speed and torque requirements of the product.

Due to the wide variety of product uses, it is difficult to achieve professional proficiency in the selection of gearmotors as a subject in a short period of time. In this case, it is best to entrust professional engineers to help with the selection, which can achieve twice the result with half the effort.

At present, micro DC reduction motors are relatively widely used. Let's take it as a simple example:

The DC voltage used for micro motors is generally below 36V. According to the needs of various batteries and applications in the market, 5V, 12V, and 24V are relatively more common. This type of deceleration motor is equipped with multiple points, such as brush motors, brushless stepper motors, and servo motors. Specific analysis of subsequent articles will be written out one by one.

Generally, a single motor has a rotational speed of thousands of revolutions, with small motors producing high rotational speed and small torque, and large motors producing low rotational speed (which can reach several hundred revolutions) and large torque. But some applications only require a few to tens of revolutions, so an acceleration and deceleration gearbox is needed. It can be understood that a gearbox is used to reduce speed and increase torque.

The efficiency varies depending on the number of stages of the gearbox. The efficiency of a general spur gearbox is 0.9, and the efficiency of the fifth stage reduction is 0.9X0.9X0.9X0.9X0.9=0.59049; The efficiency of the planetary gearbox is 0.8, and the fourth stage reduction efficiency is 0.8X0.8X0.8X0.8=0.4096