# What motors should I use that do not require gearboxes? This is a car like robot [closed]

I am new to robotics, and ime looking for a <12v motor that can be used to power a car-like robot.I will have two of these, so I can turn on-spot. Furthermore I want them not to require a gearbox, so I can just attach them to the wheels. I don't really know where to start looking for one.

I have heard servos have built in gearboxes, but don't they only have 180 degree rotation?

So does any body know a motor like I described in paragraph 1, or at least point me in the right direction?

• Servo motors can rotate $n$ degrees or have a continuous rotation. There are many different types of motor to choose from. What is the application for this car? – nFu9DT Dec 2 '14 at 4:30
• Why don't you want a gearbox? A motor with no gearbox won't have enough torque to move much weight. Is it to simplify the mechanical aspect? i.e. don't need to worry about connecting the motor to gearbox. – Ben Dec 3 '14 at 14:47

Without knowing more about your robot nobody can help size your motor. We would need to know things like weight, desired top speed, desired acceleration, where you plan to drive it (indoor vs outdoor) etc. Here is a good starting point tutorial at Society of Robots that covers how to size a motor.

That same site also has nice explanations of the different kinds of motors here.

There are many places to buy raw motors, or motors with integrated gear boxes:

Note that you can run most DC motors at a large range of voltages.

Yes, most hobby servos are not continuous rotation. But you can modify them (or buy them modified) to be continuous rotation. But there are many other better options than hobby servos. Dynamixels are nice and versatile for example.

As I mentioned in the comment, you typically don't use a motor without a gearbox because it spins too fast, and doesn't have enough torque. That is why so many motors have integrated gearboxes.

If you provide info on your robot size, weight, wheel size, required speed, etc. (perhaps in another question), I'm sure we will be able to help you pick a motor and gearbox combination for your application.