| 摘要 |
A brake master cylinder is provided to reduce the damage of a seal which is a packing member for opening and closing a cut-off hole repeatedly, and to improve durability. A brake master cylinder comprises a cylinder(1) which is empty and closed at one end, first and second pistons installed to the inside of the cylinder at regular intervals, a first liquid pressure chamber which is a space between the first piston and the second piston, a second liquid pressure chamber which is a space between the second piston and the end of the cylinder, first and second connection ports(1d) formed on the front and the rear of the upper part of the cylinder to supply air from an oil tank to the first liquid pressure chamber and the second liquid pressure chamber respectively, first and second seals(6,6a) forming a closed structure with the inside of the cylinder on the front end of the first and second pistons, first and second restoring springs(5a) installed to the first and second liquid pressure chambers to restore each piston to the original state when the pressure of an output shaft is released, a support member supporting one end of the first and second restoring springs, a guide member and a stem installed to keep the variation of oil pressure inside the first liquid pressure chamber regularly, a second guide member(10) supporting one end of the second restoring spring and installed symmetrically to the guide member on the end of the second piston, a T-shaped second stem(11) inserted to a guide hole of the second guide member to guide a rectilinear reciprocating movement of the second piston, a third guide member(12) inserted to the second stem together with the second guide member and installed symmetrically to the second guide member to support the other end of the second restoring spring, an oil inflow passage(13) connected with the second connection port to let the oil of the oil tank flow in, and a ring-shaped packing member(14) installed to the outer circumference of the second stem to open and close the oil inflow passage from the inside of the cylinder. |
