Hydraulic systems seem to have become ubiquitous. From huge cranes and excavators to disk brakes to door hinges. Basic requirement everywhere is the need to multiply force; trading greater force for lesser movement, the latter being compensated by use of electric motors or petrol/diesel engines.
My question is, when the same mechanical advantage can be obtained by using a couple of gears meshed together, why use a system that is costlier, complicated and messier ?
Advantages of hydraulics: Can transfer force through long curved paths, which otherwise would be tedious to accomplish through mechanical linkages.
Disadvantages I envision:
Use of fluids with the optimal thermal and chemical properties for the job might increase the cost.
Fluids are leaky, leakproof design adds to the cost.
Piston must be of precise dimensions without any gaps; again more investment in R&D.
Needs additional circuitry of valves, reservoir, pumping and recirculation.
So, all in all, they are increasingly used in smaller and trivial applications just because customers want it because it sounds cool to use a hydraulic device that forces fluid through a cylinder or are there real advantages ? Please explain the real benefits.