Just a few. How would Kevlar compare to aluminum in this case?How many do you need? If only a few, you might consider making a mould from that one with modelling clay. Modify the mould to suit your needs. Then cast one in the mould with a two part epoxy, include short fibres of something like Kevlar for reinforcing if needed.
That depends on the size and the forces involved in your application, which you have not yet identified.How would Kevlar compare to aluminum in this case?
This is basically attached to a high torque servo that will act as the shoulder for a robotic arm which weighs about 3 pounds. It's goal will be to raise a robotic arm that's about the length of a human arm.That depends on the size and the forces involved in your application, which you have not yet identified.
A coupling like that will tend to be expanded when torque is applied. That is because of the tooth face contact angle.
If made from something like epoxy, then winding a Kevlar thread many times around the outside will counter that expansion.
The servo is attached both front and back to the shoulder. Front being the part where the piece above attaches, and back being the opposite side on the back of the motor. The only gears are inside the servo itself. This is a very high torque servo and not a standard one. The arm itself is also very optimized for weight, the heavier parts being closer to the motor while the parts more outward are lighter, such as carbon fiber. I've tested it, it works.Consider the human arm. It has three major bones with ball joints, hanging from the shoulder with several muscles that change length. The geometry of the linkage has evolved into an optimised solution.
It is a mistake to transmit the full torque through a small diameter coupler directly from a servo motor. How will you link the servo to the arm and how many turns will the servo make to swing the arm through 90° ? Is it geared?