# Spring and damper on rocker

• Automotive
• LowBlackFast
In summary, the conversation is about an idea to use a progressive pull spring and a digressive shock on a rocker to control the timing and rotation of an axle. The person is unsure about the math behind it and wonders if it would act like a series mass damper. They also mention wanting timed compliance while maintaining torque at the axle.
LowBlackFast
Can someone help me evaluate an idea that I have?
I'm investigating the idea of placing a very progressive pull spring and a digressive shock on a rocker to control the timing and rotation of an axle.

I could be way off, but here's the scenario in my head. Both shock and spring are being pulled when a torque is applied. Spring is progressive, eventually hitting a bushing and going solid. The shock is digressive in rebound and significantly stiffer than the spring at high speed. But as the spring goes solid rotation speed of the axle will decrease. As the velocity decreases the shock becomes softer, thus allowing rotational compliance that can be "timed"

I apologize in advance if I'm ignoring some fundamentals. I believe this would act in a similar manner as a series mass damper? I'm not sure on the math. It's kinda over my head.

Thanks

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What I'm aiming to gain is timed compliance while maintaining the torque applied at the axle.

Last edited by a moderator:
berkeman
Hi LowBlackFast. This site explains the spring mass damper. https://www.shimrestackor.com/Physics/Spring_Mass_Damper/spring-mass-damper.htm

When you add all the forces of each component (the load, the damper, and the spring) you get a 2nd order differential equation. The solution the characteristic equation are the constants are tau and zeta. It seems like you are wanting the frequency which is a function of tau and zeta.

Last edited:

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