VALVE MECHANISM FOR ADJUSTING BRAKE PRESSURE

PURPOSE:To constitute a relief valve which enables steering action to be smoothly performed without generating a shock even when a spring pressure is large adjusted in a short time by forming a piston part in a valve unit. CONSTITUTION:Even when a spring 21 for setting a brake pressure is compressibly controlled in a short time, a piston part 20b suppresses a valve unit 20 from its movement being slowed. Even when the spring 21 in a compressed condition is controlled to be released in a short time, the valve unit 20 is permitted in its movement by every amount corresponding to the amount of inflow oil to the first oil chamber S1 through a clearance part T, so that the valve unit 20 is slowed in its movement. A mechanism may be constituted, fitting a piston member 28 to the inside of a tubular spacer 22 further providing thread members 29, 29, adjusting a position of this piston member 28, in a side of the spacer 22.