- #1
dmend
- 1
- 0
Hello Everyone,
I'm new to your forum and have a personal project that I need some help with. I'm not an engineering student; just a back-yard hack with a welder and grinding wheel. My project is making a chair seat with an electric motor so it rotates 1 rpm and stops. The mechanical issue I'm dealing with now is reducing the resistance produced by the seat when it is loaded. For a 200 lb person on the chair it takes 15 lbs-ft with thrust bearings installed.
Through gearing I can reduce the 15 lbs-ft to 5 lbs-ft, but I'm challenged finding a used small DC stepper motor with that power. A new motor at $350 plus is not in the budget. Even using a compound gear set-up to reduce torque I'm having a hard time finding the right motor.
So, my thinking is to reduce the resistance. I replaced the thrust bearing with a tapered roller bearing and it took up to 35 lbs-ft to rotate the loaded seat.
Chair Description:
The chair is actually a boat seat. A steel, pedestal base that supports an aluminum vertical post (1-3/4" OD). The seat base has a 3/4" steel shaft that inserts into the top of the vertical post. The vertical post does have a resin-based insert to accept the 3/4" shaft. The bearings set between top of the aluminum post and the seat base.
The drive system will be 1/4" ANSI #25 roller chain and roller chain sprockets.
Can anyone suggest a way to reduce the friction (other then using a lighter person in the seat)?
Thank-you,
dmend
I'm new to your forum and have a personal project that I need some help with. I'm not an engineering student; just a back-yard hack with a welder and grinding wheel. My project is making a chair seat with an electric motor so it rotates 1 rpm and stops. The mechanical issue I'm dealing with now is reducing the resistance produced by the seat when it is loaded. For a 200 lb person on the chair it takes 15 lbs-ft with thrust bearings installed.
Through gearing I can reduce the 15 lbs-ft to 5 lbs-ft, but I'm challenged finding a used small DC stepper motor with that power. A new motor at $350 plus is not in the budget. Even using a compound gear set-up to reduce torque I'm having a hard time finding the right motor.
So, my thinking is to reduce the resistance. I replaced the thrust bearing with a tapered roller bearing and it took up to 35 lbs-ft to rotate the loaded seat.
Chair Description:
The chair is actually a boat seat. A steel, pedestal base that supports an aluminum vertical post (1-3/4" OD). The seat base has a 3/4" steel shaft that inserts into the top of the vertical post. The vertical post does have a resin-based insert to accept the 3/4" shaft. The bearings set between top of the aluminum post and the seat base.
The drive system will be 1/4" ANSI #25 roller chain and roller chain sprockets.
Can anyone suggest a way to reduce the friction (other then using a lighter person in the seat)?
Thank-you,
dmend