- #1
mr pizzle
- 5
- 0
Hi i am currently studying a bicycle seat post suspension unit. It is one of the lower end of the range models which consists of a spring and a rubber dampener. Basic outline in cad below.
[URL=http://imageshack.us/photo/my-images/407/drawing1layout1.jpg/][PLAIN]http://imageshack.us/a/img407/1720/drawing1layout1.th.jpg[/URL][/PLAIN]
I would like to know the calculations behind the spring and damper selection. Should i be using the spring mass damper ones found on the forum in other threads. I have read a lot about shock absorber and suspension systems and have got lost in the vast amounts of information.
As i understand it (but unsure if it correct) the load from the user is initially taken up by the spring compressing. The damper (rubber/elastomer) absorbs and dissapates some of this energy through rebound resilience? (of the material used as the damper). Some energy is returned back through the spring.
If the user is 80kg and the travel of the unit is 50mm how does one go about calculating the spring and damper?
Do i need to find a spring with a constant which equals the load at given length of compression and then select the dampening to suit the amount of energy to loose from the spring? So also must need to know the relationship between when the spring is doing one thing what is the damper doing.
I think as i write this I am slightly unsure of to what going on in the system to actually understand what to calculate.
I apprieciate any feed back and would be greatful for a point in the right direction.
Regards Sean
[URL=http://imageshack.us/photo/my-images/407/drawing1layout1.jpg/][PLAIN]http://imageshack.us/a/img407/1720/drawing1layout1.th.jpg[/URL][/PLAIN]
I would like to know the calculations behind the spring and damper selection. Should i be using the spring mass damper ones found on the forum in other threads. I have read a lot about shock absorber and suspension systems and have got lost in the vast amounts of information.
As i understand it (but unsure if it correct) the load from the user is initially taken up by the spring compressing. The damper (rubber/elastomer) absorbs and dissapates some of this energy through rebound resilience? (of the material used as the damper). Some energy is returned back through the spring.
If the user is 80kg and the travel of the unit is 50mm how does one go about calculating the spring and damper?
Do i need to find a spring with a constant which equals the load at given length of compression and then select the dampening to suit the amount of energy to loose from the spring? So also must need to know the relationship between when the spring is doing one thing what is the damper doing.
I think as i write this I am slightly unsure of to what going on in the system to actually understand what to calculate.
I apprieciate any feed back and would be greatful for a point in the right direction.
Regards Sean