ecentricity of bearings

[fvincent]

I refer first to crank sliding bearings. What are the minimum clearance and the minimum eccentricity possible considering the best technology available for a let's say 100HP engine? (4 cylinders at 5000 rpm)

In fact I have in mind some special applications - a kind of gear pump or rotary engine - where eccentricity should be avoided. Any hint? The use of ball/roller bearing could reduce eccentricity for values below 0.01 mm (0.004")or even lower, considering journal load equal to 10kN at 7000 rps?

For wankel engine would be possible/benefical to replace sliding bearing by roller or ball bearings to decrease appex sealing oscillation?

Is there any possible compensation for eccentricity in such applications? I mean dynamical compensation since load vector moves direction constantly between -30o and 30o

Magnetic bearing has a future for car engines?

Bently pressurized sliding bearings?

many questions... sorry

Thanks


fvincent

 

[rnd2]

fvincent
0.01mm = 0.0004"
00.1mm = 0.004"
approximately.
Which one do you mean?

 

[fvincent]

Sorry... it is 0.01mm = 0.0004"



fvincent

 

[rnd2]

At 7000rpm a complex relationship exists between the rotational velocity, the viscousity of the fluid, load, and lift generated by the fluid that will determine the depth and "stiffness" of the film.
If your concept can't work within those parameters it probably is doomed.

 

[fvincent]

re-phrasing
My question is whether it is possible to consider regular sliding bearing, pressurized bearing and or ball/roller bearings in order to acchieve a maximum shaft eccentricity of 0.01mm (or less) when a radial force of 10kN is applied on a rotor shaft running at 7000 rpm.
The second question is whether there is any automatic device to compensate eccentricity by moving the entire bearing set in the opposite direction of the shaft center displacement. Is that feasible? reasonably cheap?

regards







fvincent

 

[rnd2]

For the first part of your question the answer is a guarded yes. Plenty of R&D to do though.
For the second part, I doubt it at 7000rpm.