Many non-professional buyers usually request when selecting a motor: the smaller the size, the better, the larger the torque, the better, the smaller the noise, the better, and the cheaper the price, the better. In fact, this selection not only increases the product cost, but also makes it difficult to select the appropriate 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 the specifications of the screws, effective depth, spacing, etc.

3. Regarding the diameter of the output shaft of the product, dimensions such as flat screws, pin holes, positioning blocks, etc., consider the installation match first.

In terms of product design, try to reserve a larger space for product assembly so that there are 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 make an estimate and buy a ready-made one in the market for testing. After it's OK, send it to the supplier for testing and confirmation. At this time, you only need to give the power-on voltage and working current.

2. Maximum allowable current and torque. Generally speaking, everyone thinks that the bigger the torque, the better. In fact, excessive torque will cause damage to the entire equipment system, cause mechanical and structural wear, and will also cause damage and insufficient lifespan to the motor and gearbox itself.

3. When selecting electrical performance, try to choose low speed and small reduction ratio, so as to obtain a product with high strength and long life.

Three: Noise selection

Usually, the noise refers to mechanical noise

1. After installing the motor into the product, it is found that the sound is relatively loud and the noise needs to be improved. Sending samples repeatedly still does not solve the problem. This situation often occurs. In fact, this kind of noise may not necessarily be the noise made by the product itself, but may be caused by a variety of noises, such as resonance caused by too fast rotation, such as resonance caused by the direct rigid cooperation of the reduction box and mechanical equipment, such as dragging a load. Noise caused by eccentricity, etc.

2. In addition, the selection of the product itself also requires strong technical support. Usually, the selection of plastic gears has lower noise than metal gears, the selection of helical gears has lower noise than spur gears, and the selection of metal worm and worm gear structures and planetary gears The box makes a lot of noise, etc. Of course, noise can also be effectively reduced by optimizing design and ensuring processing accuracy.

Four: Determine the priority direction of product assurance

1. Choose different reduction motors according to different usage environments. For example, financial machinery requires product reliability, toys require product safety and environmental protection, industrial products such as valves require priority on product life, and household products require priority on product silence.

2. Under normal circumstances, experienced engineers will tailor-make detailed products that meet the customer's requirements according to different customer requirements, and are by no means limited to meeting the speed and torque of the product.

Due to the wide variety of product uses, the selection of geared motors is a science, and it is difficult to achieve a professional level in a short time. In this case, it is best to entrust a professional engineer 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 use it to briefly explain:

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

Generally, a single motor can rotate at tens of thousands of revolutions, a small motor can produce high speed and small torque, and a large motor can produce low speed (can reach hundreds of revolutions) and large torque. But some applications only require a few or dozens of revolutions, so an acceleration and reduction gearbox is needed. It can be understood that the reduction box is used to reduce the speed and increase the torque.

The efficiency will be different if the number of reduction gearbox stages is different. Generally, the efficiency of the spur gearbox is 0.9, and the five-stage reduction efficiency is 0.9X 0.9X 0.9X 0.9X 0.9=0.59049; the efficiency of the planetary reduction gearbox is 0.8, and the four-stage reduction efficiency is 0.8X0.8X0.8X0.8=0.4096