Just day dreaming a bit I guess... Many possibilities for improving things like bicycles, scooters, drones, etc but only if they could be supplied with a transmission and motors that have 10,000 hour life cycles!
Printable View
Just day dreaming a bit I guess... Many possibilities for improving things like bicycles, scooters, drones, etc but only if they could be supplied with a transmission and motors that have 10,000 hour life cycles!
I have seen - on the internet; not in person - some giant-scale model aircraft that had hydraulic actuators for their landing gear; and there are some highly-detailed model excavators that have hydraulic drive systems. I can say that they aren't cheap... thousands of dollars. You could almost pick up a used example of the real thing for what they go for. Many off-road model buggies/trucks have hydraulic shocks; and high-end mountain bikes have hydraulic shocks as well.
Many rockets (all of them?) use hydraulic actuators for gimbaling the engines and moving any aero-surfaces they may have; and given that the rocket equation is so unrelenting; I imagine that they must have expended some effort to lighten them... perhaps like the pressure vessels that hold the helium for pressurizing the tanks, they are composite-wrapped?
i was thinking about axial piston pumps with a variable displacement as being the thing to have along with motors and cylinders
Hows this for a reason to have light weight and cheap hydraulics... A hybrid pneumatic+hydraulic pedal car where there is a compressor unit (the pedals) consisting of an axial piston pump directly connected to an axial piston motor that is compressing air. This would allow the difficulty of pedaling to stay the same irregardless of how much psi there is stored in the air tank. And the driven wheel(s) would have an axial piston air motor that is driving an axial piston pump that is driving an axial piston motor so that it can deliver more consistent speed+torque as the pressure in the tank fluctuates.
Sounds like an interesting experiment, but I think it has already been long proven that there are unrecoverable losses in fluid dynamics compared to simple mechanical drives via gears or chain methods. Hydraulics are used primarily for it's ability to provide remote power.... small compact mechanisms connected at distances otherwise inconvenient for mechanical methods, but also for predictable accuracy and smoothness.Quote:
Originally Posted by Smertrios
While an excavator or even a small hydraulically driven tractor can have no problem negotiating it's environment, it uses far more power to do so moving the volume and pressure to do so than it would mechanically IF there were a way to be as convenient to it mechanically.
Hmmmm....with hydraulics or pneumatics you are up against sliding components and that means friction and wear.....the Human body functions without a single sliding component...…..it's all about moving rigid components immersed in soft jelly with more soft jelly resisting it.
Here's an example of moving something without a single moving part.....the scissor jack, trolley jack or simple screw jack to lift a car body when you want to change a tyre....that was replaced in some places with an air bag powered by the engine exhaust gas pressure.
Oh yeah, I forgot, and a hovercraft weighing tons floats on a cushion of air without any mechanical contact with it's environment.
Ian.