1. A method of manufacturing a float valve apparatus which includes a valve case, an upper lid attached to the valve case to define a valve chamber, and a float valve liftably arranged under the valve chamber, the method comprising:
forming an exhaust hole, which communicates with a lead-out pipe of the upper lid, in an inner surface of the upper lid;
inserting a seal cap, provided separately from the upper lid, to the upper lid such that the seal cap surrounds the exhaust hole and has a valve seat on which the float valve abuts;
spin-welding the seal cap to the upper lid; and
providing the valve case on the upper lid so that the seal cap, spin-welded on the inner surface of the upper lid, is enclosed within the valve chamber, wherein the seal cap is spin-welded to the upper lid before the valve case is provided.
2. The method of manufacturing a float valve apparatus according to claim 1, further comprising:
providing a first cylindrical rib on the upper lid; and
engaging the first cylindrical rib with a step portion formed on the seal cap.
3. The method of manufacturing a float valve apparatus according to claim 2, further comprising:
inserting the first cylindrical rib into an annular groove formed on the seal cap.
4. The method of manufacturing a float valve apparatus according to claim 3, further comprising:
contacting the first cylindrical rib of the upper lid in the annular groove; and
engaging the first cylindrical rib with the step portion on the seal cap, such that a resin material between the contacting surfaces melts during spin welding.
5. The method of manufacturing a float valve apparatus according to claim 4, further comprising:
containing burrs flowing out of the first cylindrical rib in the annular groove.
6. The method of manufacturing a float valve apparatus according to claim 3, further comprising:
installing the upper lid on a positioning jig of a spin welding apparatus; and
incorporating the seal cap by fitting the annular groove into the first cylindrical rib.
7. The method of manufacturing a float valve apparatus according to claim 2, further comprising:
providing a second cylindrical rib outside of the first cylindrical rib on the inner surface of the upper lid.
8. The method of manufacturing a float valve apparatus according to claim 7, further comprising:
providing a plurality of tongues in a circumferential direction of the second cylindrical rib that project from the inner surface of the upper lid.
9. The method of manufacturing a float valve apparatus according to claim 2, further comprising:
forming protrusions on a surface of the step portion on the seal cap.
10. The method of manufacturing a float valve apparatus according to claim 1, further comprising:
providing protrusions on the seal cap; and
engaging the protrusions with a rotary holder of a spin welding device.
11. The method of manufacturing a float valve apparatus according to claim 10, further comprising:
engaging the protrusions on the seal cap with protrusions on a spin welding apparatus.
12. A method of manufacturing a float valve apparatus which includes a valve case, an upper lid attached to the valve case to define a valve chamber, and a float valve liflably arranged under the valve chamber, the method comprising:
forming an exhaust hole in an inner surface of the upper lid so as to communicate to a lead-out pipe of the upper lid;
forming a seal cap provided separately from the upper lid, the seal cap including:
inner and outer cylindrical walls defining an annular groove therebetween; and
a valve seat on which the float valve abuts; and
providing the seal cap onto the inner surface of the upper lid so that a first cylindrical rib is fitted into the annular groove;
spin-welding the seal cap to the upper lid;
providing the valve case on the upper lid so that the seal cap, spin-welded on the inner surface of the upper lid, is enclosed within the valve chamber, wherein the seal cap is spin-welded to the upper lid before the valve case is provided.
13. The method of manufacturing a float valve apparatus according to claim 12, further comprising:
providing the first cylindrical rib on the upper lid; and
engaging the first cylindrical rib with a step portion formed on the seal cap.
14. The method of manufacturing a float valve apparatus according to claim 13, further comprising:
providing a second cylindrical rib outside of the first cylindrical rib on the inner surface of the upper lid.
15. The method of manufacturing a float valve apparatus according to claim 12, further comprising:
forming the first cylindrical rib for enclosing the exhaust hole in the inner surface of the upper lid;
providing a circumferential wall for fitting into the cylindrical rib in the seal cap; and
providing a melting part melted in the case of the spin welding in a surface of contact between the cylindrical rib of the upper lid and the circumferential wall of the seal cap.
16. The method of manufacturing a float valve apparatus according to claim 12, further comprising:
providing a double cylindrical wall for enclosing a rib of the upper lid in a circumferential wall of the seal cap; and
providing a melting part in either an inner wall or an outer wall of the double cylindrical wall.
17. The method of manufacturing a float valve apparatus according to claim 12, further comprising:
providing protrusions on the seal cap; and
engaging the protrusions with a rotary holder of a spin welding device.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A brake system comprising:
a master cylinder for generating brake fluid pressure based on braking operation of a driver;
an electrical fluid pressure generator communicating with the master cylinder, and having a rear fluid chamber and a front fluid chamber generating brake fluid pressure by an electrically controllable actuator; and
a plurality of wheel cylinders communicating with the rear fluid chamber and the front fluid chamber, respectively, and generating a braking force for braking wheels so that when the electrical fluid pressure generator fails, the wheel cylinders are operated by the brake fluid pressure generated by the master cylinder;
the electrical fluid pressure generator including:
a rear piston and a front piston which are advanced by the actuator to generate brake fluid pressure in the rear fluid chamber and the front fluid chamber, respectively;
a rear inlet port and a rear outlet port which are formed in the rear fluid chamber and connected to the master cylinder and the wheel cylinder, respectively;
a front inlet port and a front outlet port which are formed in the front fluid chamber and connected to the master cylinder and the wheel cylinder, respectively;
a rear first cup seal arranged at a front end of the rear piston so as to face forward;
a rear second cup seal arranged at a rear end of the rear piston so as to face forward;
a front first cup seal arranged at a front end of the front piston so as to face forward;
a front second cup seal arranged at a rear end of the front piston so as to face rearward; and
a rear supply port formed adjacent to and in the rear of the rear inlet port, and a front supply port formed adjacent to and in the rear of the front inlet port, the rear and front supply ports being connected to a reservoir.
2. The brake system according to claim 1, further comprising an anti-lock braking system (\u201cABS\u201d) provided between the electrical fluid pressure generator and the wheel cylinder, the ABS decreasing, maintaining and increasing brake fluid pressure transmitted to the wheel cylinder in order to suppress locking of a wheel upon braking.
3. The brake system according to claim 2, further comprising a shutoff valve provided between the master cylinder and the electrical fluid pressure generator, the shutoff valve being closed at least during operation of the ABS.
4. The brake system according to claim 1, wherein a fluid passage extended from the rear supply port and another fluid passage extended from the front supply port are connected together into a single fluid passage which is connected to the reservoir of the master cylinder.
5. The brake system according to claim 1, further comprising a fluid pressure sensor for detecting brake fluid pressure generated by the master cylinder, and which is provided in a fluid pressure system in which a stroke simulator is arranged.
6. A brake system comprising:
a master cylinder for generating brake fluid pressure based on braking operation of a driver;
an electrical fluid pressure generator communicating with the master cylinder, and having a rear fluid chamber and a front fluid chamber generating brake fluid pressure by an electrically controllable actuator; and
a plurality of wheel cylinders communicating with the rear fluid chamber and the front fluid chamber, respectively, and generating a braking force for braking wheels so that when the electrical fluid pressure generator fails, the wheel cylinders are operated by the brake fluid pressure generated by the master cylinder;
the electrical fluid pressure generator including:
a rear piston and a front piston which are advanced by the actuator to generate brake fluid pressure in the rear fluid chamber and the front fluid chamber, respectively;
a rear inlet port and a rear outlet port which are formed in the rear fluid chamber and connected to the master cylinder and the wheel cylinder, respectively;
a front inlet port and a front outlet port which are formed in the front fluid chamber and connected to the master cylinder and the wheel cylinder, respectively;
a rear first cup seal arranged at a front end of the rear piston so as to face forward;
a rear second cup seal arranged at a rear end of the rear piston so as to face forward;
a front first cup seal arranged at a front end of the front piston so as to face forward;
a front second cup seal arranged at a rear end of the front piston so as to face rearward; and
a means for preventing leakage of the brake fluid of the front fluid chamber through the rear fluid chamber;
wherein the means for preventing leakage of the brake fluid of the front fluid chamber through the rear fluid chamber comprises a rear supply port formed adjacent to and in the rear of the rear inlet port, and a front supply port formed adjacent to and in the rear of the front inlet port, the rear and front supply ports being connected to a reservoir.
7. The brake system according to claim 6, wherein the reservoir is connected to the master cylinder, and a fluid passage extended from the rear supply port and another fluid passage extended from the front supply port are connected together into a single fluid passage which is connected to the reservoir.
8. The brake system according to claim 6, further comprising a fluid pressure sensor for detecting brake fluid pressure generated by the master cylinder, and which is provided in a fluid pressure system in which a stroke simulator is arranged.