1、Descrition of Slotless BLDC Motor  

The winding of a slotless BLDC motor is not wound around stator teeth compared With a traditional Brushless motor. Instead, it is an ironless, cylindrically shaped self-supporting structure placed within the motor air gap between the stator back iron laminations and the rotor assembly. The slotless designs eliminate cogging torque, yielding a motor with very smooth rotation, and reduced vibration and audible noise level.  The rotor is similar to that used in the traditional brushless motor. It has a number of Arc magnets that define the motor poles and are affixed to a rotor core centered about and fixed to the motor shaft. The magnets are usually a high-strength, RE Magnets, such as NdFeB or SmCo. Slotless BLDC motor consists of a stator winding positioned inside a Laminated stator ring with teethfree and a permanent magnet motor. This provides more peripheral space for the stator winding. This also provides more effective magnet surface area and air-gap flux. Strong RE magnets enable high torque to motor weight ratio very possible. Stator with teethfree, it enables more winding copper and power density which can produce more torque. Of course, coggingfree and audible noise level down are easily achieved.

2、Slotless BLDC Motor Basical Confiquration

Unlike conventional slotted brushless motors, slotless motor wires are directly wound into a cylindrical shape and are encapsulated in a high-temperature epoxy resin to maintain their orientation with respect to the stator laminations and housing assembly. This configuration, which replaces the stator teeth, eliminates cogging altogether and results in desired quiet operation and smooth performance.The slotless design also reduces damping losses related to eddy currents. These currents are quite weaker in a slotless motor, regarding the gap between the laminated iron and magnets is quite bigger than in a slotted motor. Slotless motors are typically designed with sinusoidal torque output that produces negligible distortion, rather then a trapezoidal voltage output. The sinusoidal output reduces torque ripple, especially when used with a sinusoidal driver.
Because of the slotless design no stator teeth to interact with the permanent magnets, the motor does not generate detent torque. In addition, low magnetic field saturation allows the motor to run at several times its rated power for short intervals without perceptible torque roll-off at higher power levels. Compared with slotted motors, slotless construction also can significantly reduce     inductance to improve current bandwidth. The teeth in a slotted motor naturally arise more inductance: the coils of copper wire around the teeth interact with the iron in a slotted motor, and this interaction tends to send the current back on itself, resulting in more damping (or dragging) and impacting negatively on  slotted motor response and acceleration. In terms of delivering power,conventional slotted motors used to enjoy the advantage over slotless types, due (as noted) to the proximity of iron and magnets and the reduced air gap.However, this advantage has virtually evaporated, in large part due to the utilization of high-energy, RE magnets (such as SmCo and NdFeB). By incorporating these magnets, manufacturers of slotless brushless motors have been able to routinely compensate for the greater air-gap distance. These more powerful magnets
effectively enable the same (or better) torque performance for slotless products compared with slotted. Eliminating the teeth and using stronger magnets both serve to maximize the strength of the electromagnetic field for optimum power output. RE magnets, along with the fact that fewer coils, or "turns," of the wire are required in slotless motors, also help contribute to low electrical resistance, low winding inductance, low static friction, and high thermal efficiency in slotless motor types. One more important difference between slotless and slotted designs is the rotor       diameter. Slotless motors have a larger rotor diameter than slotted construction for the same outside motor diameter and will generate a higher inertia, as well as accommodating more magnet material for greater torque. For applications with high-inertia loads, the slotless product is more likely to be specified.

3、Advantages and Features of Slotess BLDC Motor
Slotless BLDC designs show many advantages over conventional slotted stator construction. Coggingfree provides improved servo efficiency and enable extremely smooth, quiet motion. Low inductanceand high current bandwidth provides precise control and location. Slotless construction also provide excellent winding heat transfer for high thermal efficiency and transient load capacity. these motors are easily achieved in size smaller, weight lighter and more efficient than traditional
brush motors with comparable outputs.
3-1   Zero-Cogging torque for smooth operation and vibration minimization
3-2   High speed capability of up to 120,000 RPM
3-3   Excellent power-to-weight ratio enabling the design of compact, light-weight hand tools
3-4   Protected windings for applications requiring autoclavability
3-5   Hall sensors with pullup resistors and bypass capacitors for electrical noise suppression
3-6   RE (NdFeB or SmCo) magnets make torque output maximization
3-7   Low loss lamination material for increased performance
3-8   Exceelent life, smooth high speed operation and lower audible noise level
3-9   Higher Temperature insulation Grade for higher reliability

4、Slotless BLDC Motor types which Toptech makes
4-1  Slotless BLDC RE Magnet Motor: JRBLN-X

5、Slotless BLDC RE Magnet Motor Drive System:

  If needed, contact with Toptech  Engineers

6、Main Application of Slotless BLDC Motor

Medical
6-1    Powered surgical handpieces
6-2    Surgical robot systems
6-3    Prosthetic limb drive systems
6-4    High speed medical drills
6-5    Small centrifuges

Factory Automation
6-6    Semiconductor device assembly and test systems
6-7    High speed miniature spindles
6-8    High speed pick and place electronic assembly systems
6-9    Rotating adhesive/coatings dispensing systems
6-10   High speed semiconductor drills

Military Application
6-11   Air Forec such as position elements drives system
6-12   Navy such as low noise or Noisefree equipments or underwater Navigator

7、Slotless BLDC Motor Order Information Necessary

E-mail:    hktoptech@toptechelectric.com  
Website:   www.toptechelectric.com    

Military Application
6-11   Air Forec such as position elements drives system

6-12   Navy such as low noise or Noisefree equipments or underwater Navigator

Military Application
6-11   Air Forec such as position elements drives system
6-12   Navy such as low noise or Noisefree equipments or underwater Navigator