In MOONS' slotless & coreless series motors, the windings are patented (patent pending: winding structure to reduce the thickness of the motor's end, patent authorization number: ZL201510121440.7). This design offers high torque, high torque, and low noise. Its compact size and lack of cogging result in smoother high-speed and low-speed operation, more precise control, and higher efficiency.
With 11 types of winding, theØ13mm series slotless BLDC motors are available in long and short versions with 2 different output powers. MOONS' new micro motions system includes a slotless motor, gearbox, encoder, driver, and mechanical components.
Coreless Brushed DC Motors have excellent performance and are easier to control. We provide three types of coreless brushed DC motors whose diameters are 13mm, 17mm, and 24mm, with hollow rotor design, which feature high acceleration, low rotational inertia, no cogging effect, no iron loss, compactness, and lightness.
MOONS' exhibited slotless and coreless products in Beijing International Medical Equipment Fair in 2019.
■ What is a coreless motors?
The coreless motor breaks through the rotor structure of the traditional motor in structure, and adopts an ironless rotor, also called a coreless rotor. By eliminating eddy currents formed by the iron core, this novel rotor structure eliminates power loss. Additionally, the rotor's weight and moment of inertia are greatly reduced, which reduces its mechanical energy loss. Due to the structural change of the rotor, the running characteristics of the motor have been greatly improved, which not only has outstanding energy-saving characteristics but more importantly, has the control and drag characteristics that cannot be achieved by iron core motors. Coreless motors are servo-controlled motors with DC permanent magnets, and can also be referred to as micromotors. The coreless motor has outstanding energy-saving characteristics, sensitive and convenient control characteristics, and stable operation characteristics, and has obvious technical advantages. In many fields, electric motors are being developed as high-efficiency energy conversion devices.
■ Self-supporting winding technology for coreless motors
The self-supporting winding of the coreless is made of enameled wire. The enameled wire is composed of two parts: a copper conductor and an insulating paint layer. After the bare wire is softened by annealing, it is painted and baked many times. During the manufacturing process, the paint on adjacent copper wires is melted together by applying pressure and temperature. Paint is a thermoplastic that contains a solvent that makes it easy to mold. Due to the high-temperature manufacturing process, the solvent gas escapes, the thermoplastic becomes hard, and the winding becomes stable and stiff. The strength and dimensional stability of the wrap can be further enhanced by proper bonding (tape or fiberglass). This is especially important in the case of high current and high load because, in the case of high current and high load, the heating value of the winding increases and the paint becomes softer.
■ Classification of coreless motors
Slotless Motor DC brushless cogging motor, commonly known as "brushless coreless" in the industry.
Coreless Motor DC brushed ironless motor, commonly known as "brush coreless" in the industry.
■ Structural differences between brushed coreless and brushless coreless
The coreless motor is divided into two types: brushed and brushless. There is no iron core in the rotor of the brushed motor, and there is no iron core in the stator of the brushless motor (also known as the Cogged brushless motor). Based on the figure below, the difference between the two motors is that the brushed coreless motor uses a carbon brush (or metal brush) and a commutator for commutation. The brushless coreless motor has no physical structure, the coil wire is directly connected to the controller, and commutation is completed by processing the position signal fed back by the Hall on the connecting plate; the brushed coreless motor is a coil, and the commutator and the connecting plate rotate between the shell and the permanent magnet, and they together form the rotor. The coil of the brushless coreless is fixed, and the permanent magnet rotates in the middle as the rotor. MOONS' has developed brushless coreless motors with frame sizes of φ13mm, φ16mm, φ22mm, and φ30mm. The no-load speed of the motor can reach 15000rpm~50000rpm; φ13mm, φ16mm, φ17mm, φ24mm, and many other frame sizes, the no-load speed of the motor is 10000rpm~16000rpm, the coreless motor can also be used as a torque motor and positional motor after matching with reducers with different speed ratios and encoders with different resolutions The device used for feedback.
Structural diagram of coreless motor
Structural diagram of slotless motor
■ Features of coreless motor
Smooth operation at low speed No cogging, Low vibration, low noise Rotor can be controlled in any position
Better magnetic circuit design Higher power density Low temperature rise, high efficiency
High dynamic response High acceleration
■ Brushless coreless motor (brushless without cogging) and brushed coreless motor
Long life (20000h)
Limited motor life (2000h)
Electromagnetic interference can be ignored
With iron loss
Without iron loss
Requires drive control
■ Industry application of coreless motor?
As the coreless motor avoids various technical drawbacks of the iron core motor, and its outstanding features are concentrated in its main performance, it has a wide range of applications. With the rapid development of industrial technology, higher expectations for the servo characteristics of motors are continually being raised, making coreless motors irreplaceable in many applications. Since coreless motors entered the large industrial and civil fields from the military and high-tech fields, especially in industrialized countries, they have been used in virtually all industries and have impacted most products. 1. Fast-response follow-up system. With its rapid adjustment of the missile's flight direction, follow-up control of a high-magnification optical drive, rapid automatic focusing, highly sensitive recording and detection equipment, industrial robots, bionic prostheses, etc., the coreless motor can easily meet its technical requirements. 2. Driving components that require smooth and long-lasting drag. The power supply time can be more than doubled with the same power supplies for portable instruments, personal portable equipment, field equipment, etc. 3. Various aircraft, including aviation, aerospace, model aircraft, etc. As a result of the lightweight, small size, and low energy consumption of the coreless motor, the aircraft's weight can be greatly reduced. 4. As well as optical instruments, medical equipment, robots, etc., subdivided applications include dental equipment, micro-pumps, infrared lenses, pipetting modules, grippers, robotic hands, dispensing valves, surgical tools, etc.