What to look for?
Many beginners are tricked by the apparent ease with which mobile robot wheels can be supposedly connected to motors. In many designs, the wheels are driven directly by a motor shaft or gearbox. In smaller, lightweight amateur robots, a press-fit connection can be used - some wheels have been adapted to this method of mounting, and the only thing to look for is to match the diameter of the wheel mounting hole to the dimensions of the motor axis. However, larger or more precise designs require other mounting methods that not only provide adequate rigidity (no excessive play) but also strength and stability. In such applications, aluminum motor adapters, commonly called mounting hubs, come to the rescue. Hubs take the form of rings that are fastened to the drive shaft by a clamping screw, and the driven element (e.g. a wheel) is connected to the adapter via four tapped holes.
Other adapter variants
In addition to clamping hubs (suitable for drive shafts with diameters from 3 mm to 8 mm), we also offer motor adapters in the form of hexagonal sleeves that are clamped by screws on both sides. Each adapter of this type is adjusted to strictly specified shaft diameters - the elements available in our store have on one side a hole of 12 mm diameter, and on the other side - 3 mm, 4 mm or 6 mm. Of course, in addition to attaching the drive wheels of mobile robots, this type of elements can also be used in other mechanisms - for example to connect the axes of stepper motors to the drive screws of CNC devices or self-constructed 3D printers. In this category you will also find a number of other types of adapters for motors, such as bearing pulleys (smooth or toothed), clamping hubs compatible with MakeBlock system or adapters that allow you to connect different types of motors to LEGO wheels.
Connecting encoders to robot mechanics
Special attention should be paid to how the motor shaft is connected to the encoder axis. Because encoders are precise and relatively delicate sensors, they should not be subjected to any vibration or stress that might occur if the sensor axis is not correlated accurately enough with the motor shaft axis. In such situations, flexible motor adapters, usually called encoder couplers, should be used. These types of components accurately transfer the rotation to the encoder shaft, reducing unwanted circular movement of the axis (so-called runout) and thus protecting the sensitive encoder interior.