Solid-type brake disc and method of manufacturing the same
Disclosed is a solid-type brake disc including a hat part, which includes a circular main body mounted on a rotation shaft of a wheel, and a plurality of protrusions protruding in a circumferential direction from an outside surface of the main body, and a friction part, which includes a ring body having a through-hole formed in the center thereof for receiving the hat part in the through-hole, and recessed portions protruding from the periphery of the through-hole toward the respective protrusions, the recessed portions being connected to the respective protrusions to enclose the protrusions.
1. A solid-type brake disc comprising:
a hat part including a circular main body mounted on a rotation shaft of a wheel, and a plurality of protrusions protruding in a circumferential direction from an outside surface of the main body; and
a friction part including a ring body having a through-opening formed in a center thereof for receiving the hat part in the through-opening, and recessed portions protruding from a periphery of the through-opening toward the respective protrusions, the recessed portions being connected to the respective protrusions to enclose the protrusions,
wherein a ratio of a length that each protrusion protrudes from the outside surface of the main body in a radial direction to a length from an end portion of each recessed portion to an outer periphery of the ring body ranges from 0.18 to 0.28.
2. The brake disc according to claim 1 , wherein each of the recessed portions has an end portion in contact with the outside surface of the main body, and is provided with an inside space for enclosing a corresponding one of the protrusions.
3. The brake disc according to claim 1 , wherein each of the protrusions is divided into a first protruding body, which protrudes from the outside surface of the main body and is shaped to be reduced in thickness with decreasing distance to an end portion thereof in an axial direction, and a second protruding body, which extends outward from the first protruding body and is shaped to be increased in thickness with decreasing distance to an end portion thereof, wherein the protrusion is thinnest at a boundary between the first protruding body and the second protruding body.
4. The brake disc according to claim 1 , wherein each of the protrusions is shaped to be reduced in width with decreasing distance to an end portion thereof.
5. The brake disc according to claim 3 , wherein a ratio of a thickness at a boundary between the first protruding body and the second protruding body to a thickness of the ring body ranges from 0.35 to 0.40.
6. The brake disc according to claim 3 , wherein the second protruding body has upper and lower slopes in an axial direction, and is formed to be tilted upward and downward by an angle of 1.5 to 2 degrees relative to imaginary lines that extend in parallel to a radial direction at an upper end portion and a lower end portion of a boundary between the first protruding body and the second protruding body.
7. The brake disc according to claim 1 , wherein the protrusions and the recessed portions form a plurality of bridges, which are spaced apart from one another by a same distance along an outside surface of the main body and a periphery of the through-opening to form discharge openings between the bridges.
8. The brake disc according to claim 7 , wherein a number of bridges is nine.
9. A method of manufacturing a solid-type brake disc, the method comprising:
cast-molding a hat part, which includes a circular main body mounted on a rotation shaft of a wheel and a plurality of protrusions protruding from an outside surface of the main body in a circumferential direction;
inserting the hat part into a mold; and
cast-molding a friction part, which includes a ring body having a through-opening in a center thereof for receiving the hat part in the through-opening and recessed portions protruding from a periphery of the through-opening toward the respective protrusions, the recessed portions being connected to the respective protrusions to enclose the protrusions, via casting,
wherein a ratio of a length that each protrusion protrudes from the outside surface of the main body in a radial direction to a length from an end portion of each recessed portion to an outer periphery of the ring body ranges from 0.18 to 0.28.
10. The method according to claim 9 , wherein, in the cast-molding the hat part and the cast-molding the friction part, cast iron is used to cast the hat part and the friction part, and a strength of the cast iron used to cast the hat part is higher than a strength of the cast iron used to cast the friction part.