Writer： admin Time：2020-06-16 10:58 Browse：℃
With the recent outbreak of COVID-19, how the governments and hospitals of various countries respond to this global crisis in the coming weeks will have a profound and ever-increasing impact on people's lives and society. The demand for medical equipment is increasing rapidly, and many of these devices rely on precise motors to work. COVID-19 is a respiratory disease. Due to pneumonia and other serious respiratory diseases, it is difficult for patients to breathe. Patients like this usually need a ventilator to help them breathe. A key component of the ventilator is a motor that helps pump air, making it easier for patients to breathe. These devices can be combined with different types of motors, such as hybrid stepper motors, standard brushless DC motors, frameless brushless DC motors or slotless coreless brushless DC motors.
In most cases, medical applications exhibit space constraints, so the smaller the available motor, the better for the design engineer. Smaller motors require less power during operation, so energy costs can be saved. However, small motors also have shortcomings. The main shortcoming is reduced torque. Although you might think that smaller means lower costs, manufacturing small and precise motors usually costs more. The stepper motor has high accuracy, quiet operation and small size, which is very suitable for medical equipment and applications. These characteristics are the result of the appropriate process and quality required in the manufacturing and assembly of stepper motors, all of which means that design engineers who incorporate micro stepper motors into their medical device designs must weigh the trade-offs.
The medical application field involves complex cutting in the patient's eyes, pumping critical body fluids, or any other type of medical application, and must consider the size, accuracy, smoothness of motion, noise level, quality, and reliability of the motor. By increasing the step angle from the typical 1.8 degrees to 3.46 degrees, the stepper motor can achieve nearly twice the torque as a design and nearly four times the holding torque up to 0.01Nm) similar to the size of the traditional permanent magnet stepper motor ( The highest is 3.53×10-3Nm). In addition, a typical permanent magnet motor has 20 steps per revolution, that is, a step angle of 18 degrees. The resolution of a 3.46 degree motor is 5.7 times that of a common permanent magnet motor. The higher resolution translates directly into higher accuracy, providing the benefits of a hybrid stepper motor, rather than the disadvantages of a permanent magnet motor. In addition to this step angle change, a low-inertia rotor design is also used, and the motor can obtain a dynamic torque of more than 0.01Nm at a speed close to 8000 rpm, thereby providing speed performance similar to a standard brushless DC motor.
When it comes to the size of the motor, the length is usually the key to installing the motor in medical equipment. The length may vary from motor manufacturer to manufacturer and will change with redesigns and upgrades. The hybrid stepper motor is easy to adjust and fully meets the design requirements. Generally speaking, the stepper motor has a standard square flange and is mounted on the bracket. But for some motors, especially modular motors, the demand for customized housings is greater. Using a modular motor design, they molded it into a plastic housing without the need for screws to install the motor, which saved space and made the device small enough to be handheld. The stepper motor rotates in degrees, and the increment of each step can be 1.8°, 0.9°, or even 0.45°, which is the inherent natural stepping of the motor. When micro-stepping, the motor is forced to take finer increments with each movement. A 0.9 degree motor can be further stepped every 0.45 degrees, which is called half step. The 64 micro-stepping motor divides 0.9 degrees into 64 steps, with 0.014 degrees per step. The micro-stepping is usually handled by the driver electronics.
When looking for a reliable stepper motor, engineers often request to provide mean time between failure (MTBF) data to ensure that the potential motor can last for a certain period. The average trouble-free working time of stepper motors usually exceeds 20,000 hours. When the stepper motor is operated under the rated axial and radial loads of its bearings or when the temperature is below 50°C, the stepper motor usually lasts for 20 years, assuming a 50% duty cycle.
Introduction of Zhengde stepper motor: 15BY25-166 permanent magnet stepper motor
Main application areas: pin printers, electronic scales, attendance machines, etc.
Model Item Item Specification Spec
15BY25-166 Driving Voltage 5±10%VDC
Exciting Method 2-2
Exciting Mode Bipolar
Step Angle 18±7%°
Rotor Inertia 0.06gcm²
Turn to Rotation CW/CCW
Maximum pull-in frequency Max.pull-in Frequency 1100Hz
Maximum pull-out frequency Max.pull-out Frequency 1500Hz
Holding Torque Holding Torque 30gf.cm (5VDC)
Positioning torque Detent Torque 7gf.cm
Insulation Resistance 100MΩ 500VDC
Noise Noise ≤40dB