Common brushless motor stators with inward-facing slots typically utilize specialized inner winding machines, available in two, four, six, or eight stations. However, different machines also offer different winding methods, with top winding and bottom winding being the most common. So, what’s the difference between top and bottom winding on a needle-type inner winding machine? What are the differences in the wire feeding methods? Vacuz will explain.

I. The Core Differences Between Top and Bottom Winding

1. Winding Direction and Mold Positioning

Top Winding: The needle begins winding from the top of the stator. The nozzle moves up and down, driven by a servo motor, while the mold rotates left and right to arrange the wire. Initial mold positioning must be accurate to ensure the nozzle is aligned with the slot to prevent winding deviation.

Bottom Winding: The needle begins winding from the bottom of the stator. The principle is similar to top winding, but the mold’s rotation direction or initial angle may be adjusted to accommodate the spatial layout of the bottom winding.

2. Applicable Product Differences

Top Winding: Commonly used in stator products such as pumps, stepper motors, servo motors, household appliances, and medical devices. These products require high winding accuracy and slot fill rate.

Bottom Winding: Commonly used in stators for power tool motors and garden tool motors. Due to structural limitations or process requirements, these products may require bottom winding to optimize space utilization.

3. Equipment Configuration and Workstation Selection

Both types are available in two-, four-, or six-station configurations.

Bottom winding equipment may feature optimized die designs for thick wire or special slot shapes to reduce winding resistance.

Both types can achieve no-load speeds of up to 800 rpm, but actual winding speed is affected by wire diameter, number of slots, and wire density.

II. Differences in Wire Feeding Methods

1. Wire Feeding Path for Top Winding

After being drawn from the spool, the enameled wire passes through a tensioner and guide pulley into the needle bar nozzle. The nozzle drives the wire into the slot as the needle bar moves up and down.

As the die rotates, the nozzle must move back and forth synchronously to ensure the wire is arranged in layers within the slots, preventing overlap or damage.

Key Point: The coordinated movement of the nozzle and die requires high precision; otherwise, it can easily lead to chaotic wire routing or wire breakage.

2. Wire Path for Lower Winding

The enameled wire path is similar to that for upper winding, but the nozzle must enter the slots from below the stator. The die’s rotation direction or initial angle may need to be adjusted to accommodate the spatial layout of the lower winding.

For thick wire or unusual slot shapes, the nozzle may feature a wider design or special materials to reduce winding resistance and prevent wire damage.

Key Point: For lower winding, ensure that the wire does not interfere with the die, and the wire density must meet product performance requirements.

Selection Recommendation:

For products with high winding accuracy and slot fill requirements (such as medical devices and precision servo motors), upper winding equipment is preferred.

If your product has a thicker wire diameter or a special groove shape (such as in power tool motors) and you need to control costs, you may consider using a winding machine, but ensure the mold design can meet your wire routing requirements.

Vacuz hopes the above information meets your needs. If you have further questions about needle-type internal winding machines or related technologies, or if you have any feedback on this content, please feel free to let Vacuz know so that we can better serve you.

E-mail: sales@vacuz.com