Hi im new in the robot community.
I am currently trying to create a 400400530mm 4WD Mecanum Robot which is expected to weight/carry up to 50kg load.
The question is whether it is better to directly connect the motor shaft on the wheel or to use an intermediary shaft/hub between the two?
What are the determining factors when taking this decision?
Thanks in advance for your comments.
Literally just the radial load (rating) of the motor shaft, factoring in any bumps, slightly offset wheels etc. If the axial load of the motor’s shaft is (random example) 10Kg and your four wheel robot weighs 50Kg, then the load per shaft is above their rating and they would break. Often the output shaft of a planetary gear motor is only supported by one radial ball bearing and is not intended to support a radial (or axial) load. However for smaller robots, the total weight is not too high and it’s not an issue (worth the savings in complexity and cost). 50Kg is a pretty big robot so you’re likely looking at supporting the wheels from a separate shaft (connected to the motor’s shaft by a chain, timing belt, gears etc). A direct drive BLDC motor is a different question (“hub motor” style for example).
Thanks for the answer, as the axial load a motor can carry is rarely specified in the basic characteristics I didn’t knew in which direction I was supposed to look into.
Is it also relevant to use connector like this one (right after the wheel and a bearing)?
ServoCity Flexible Clamping Shaft Coupler 0.250in to 6mm - RobotShop
Not particularly. That’s used largely to connect one shaft to another and help a bit if they’re offset or one is torqued very quickly.
If possible, a medium sized robot’s wheel would be supported on one side by the motor’s shaft, and on the other side by a ball bearing.
