How to Reduce Noise for DC Spur Gear Motor?

The Pros and Cons of Spur Gear？
Usually, we say spur gear, and we mean a normal spur gear motor. DC spur gear motor, also known as DC motors with the spur gearbox, are widely used in different daily applications, like electronic lock, vending machines, valves, smart curtains, etc.

There are many advantages of spur gear motor. Firstly, the gearbox efficiency is much higher than that of the right angle gearbox. Secondly, with a spur gearbox, we can combine different gear ratios to fit for different applications. Moreover, costly effectiveness is a big advantage of DC spur gear motor, compared with other gearboxes like a planetary gearbox. This is also the main reason why it is the most widely used gearbox type in daily automation products. For these spur gears, the custom materials include metal and POM, and metal gears are much stronger, while POM gears are much better in sound performance.

Compared with the planetary gearbox, the efficiency of the spur gearbox is also a disadvantage. With the same driving motor and same gear ratio, the spur gear motor can not produce such high torque as the planetary gear motor.

The solutions to reduce dc spur gear motor noise
Currently, we are working on an office facility project, which has strict noise requirements for the spur gear motor. According to the customer’s requirements, we worked out the first version solution DM-37RS5450244800-10K. This solution meets the requirements of the rated torque of around 1kgf.cm at the speed of 350rpm, this solution’s total length also suits the customer’s request. However, tests on the customer side showed that the noise level is not good, especially the noise greatly changed in the loading process.

With the above feedback, we analyze the backup samples and confirm that the unexpected noise comes from both the gearbox and the driving DC motor. For the gearbox, we tried different combinations of gear. The first one is normal plastic gear with robbing gear; the second one is bake-lite gear with robbing gear; the third one is PEEK plastic gear with robbing gear. Compared with all the 3 combinations, we found that the 2nd solution(bake-lite gear with robbing gear) is the best, especially the performance while loading. The third one is also very nice. Finally, we have a meeting with clients, advising the pros and cons of both the 2nd and 3rd solutions. The bake-lite gear is with good performance, but it is too weak to run in the gearbox well over a long period, and it is also difficult to conduct in the production process. With the testing videos for the noise, the customer finally chose the 3rd solution, using PEEK plastic gear with robbing gear in the gearbox.

Moreover, we found the driving DC motor is also another issue in producing the noise. The original 545 is an open-type dc motor with heat sinkholes. We choose this motor for the first version sample due to the high torque and reasonable length. It is not easy to find an alternative. We tested a few possible solutions, and finally developed a driving DC motor 3042. The diameter is 30mm while the length is 42mm, the size is much smaller than 545, but it produces similar torque with 545 at the same speed due to the strong magnets. Most importantly, the motor DM-3042 is fully closed and has a great noise performance. At last, we tried the combination DM-37RS30420244300-10K and tested in our lab, sent the videos to customers, and they were very satisfied.