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Thread: Brake bias valves, how do they work?

  1. #1
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    Question Brake bias valves, how do they work?

    I don't really understand how these work.

    wwvalve.jpg

    Let me explain. Brakes work on pressure, not fluid flow. I get that there IS a very slight amount of fluid flow.
    How do these valves reduce pressure on the down side of the valve for more than a fraction of a second?
    I could see where they might reduce the rate at which braking pressure is applied.

    Do they really reduce braking bias for long applications of braking (e.g. at end of straight where brakes might be applied for a few seconds)?
    Am I missing something?

  2. #2
    Def's Avatar
    Def is offline Lead Disagreement Eng PE
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    It's not a "valve" per say, it's actually a pressure regulator that has an outlet pressure gain set by the geometry of the internal components (i.e. the 57% pressure gain you get on the outlet vs. inlet above the knee point).

    This has some information on how it functions, and I'd assume it's a single stage regulator due to the size and application:

    https://en.wikipedia.org/wiki/Pressure_regulator


    At least that's my understanding of how they work without cutting one open, but it seems consistent with their operation. You're right in that it can't be something like a needle valve, as that only throttles pressure based on pressure drop vs. flow.

  3. #3
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    BINGO!! This makes perfect sense now. Not a flow rate regulator but a pressure regulator (by regulating the volume).
    Thanks!!

    Quote Originally Posted by Def View Post
    It's not a "valve" per say, it's actually a pressure regulator that has an outlet pressure gain set by the geometry of the internal components (i.e. the 57% pressure gain you get on the outlet vs. inlet above the knee point).

    This has some information on how it functions, and I'd assume it's a single stage regulator due to the size and application:

    https://en.wikipedia.org/wiki/Pressure_regulator


    At least that's my understanding of how they work without cutting one open, but it seems consistent with their operation. You're right in that it can't be something like a needle valve, as that only throttles pressure based on pressure drop vs. flow.

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