JPH0861403A - Brake rotor and metal mold for casting therefor - Google Patents

Abstract

PURPOSE: To simplify a casting process while securing cooling performance. CONSTITUTION: Plural air passages 1 disposed in the central part of the board thickness of an annular disc part 2 are formed substantially in parallel to each other in the radial direction in the respective fan-shaped parts 2a, 2b, 2c formed by dividing the disc part into plural part in the circumferential direction. On the other hand, a metal mold for manufacturing the above brake rotor comprises a pair of molds which are opposite to each other in the axial direction of the brake rotor and have the divided faces on one friction surface of the disc part, wherein one of molds for forming the other friction surface and the outer peripheral surface of the disc part is formed in such a manner as to be divided to be drawn in the radial direction, and plural air passage forming male molds are projected from the face for forming the outer peripheral surface of the disc part inwards in the drawing direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake rotor for a disc brake and a die for casting the same, and more particularly to a brake rotor having an air passage formed in the center of the disc portion in the plate thickness direction and a die for casting the same. It is a thing.

[0002]

2. Description of the Related Art In order to prevent deterioration of braking performance due to heating of a brake pad, so-called heat fade, a so-called ventilator in which a ventilation passage is formed in a central portion of a plate portion of a brake rotor so as to increase a heat radiation area. Ted disc brakes are known. Conventionally, a plurality of ventilation passages of such a brake rotor are generally formed radially so as to penetrate between the inner and outer peripheries of the disk portion (see Japanese Utility Model Publication No. 5-1703).

[0003]

However, in such a conventional type brake rotor, since the ventilation passage is radial, molding is substantially impossible unless a sand core is used for the convenience of die cutting. there were. Therefore, sand removal is troublesome, and there is a disadvantage that the manufacturing process is complicated and the manufacturing cost is increased.

The present invention has been devised in order to eliminate such disadvantages of the prior art, and its main purpose is to:
It is an object of the present invention to provide a brake rotor capable of simplifying the casting process while ensuring cooling performance, and a die for casting the brake rotor.

[0005]

According to the present invention, the above-mentioned object is a brake rotor in which an air passage is formed in a center portion in the plate thickness direction of an annular disc portion, wherein the air passage has the above-mentioned structure. This is achieved by providing a brake rotor characterized in that a plurality of fan-shaped portions formed by dividing the disk portion into a plurality of portions in the circumferential direction are formed substantially parallel to the radial direction thereof.

In particular, in each of the plurality of fan-shaped portions, the ventilation passages are formed in the same arrangement at substantially equal intervals substantially parallel to the median line of the central angle of the fan-shaped portions, and the outer peripheral side is in the axial direction. And it is preferable that the width is increased in the radial direction. Moreover,
It is preferable that a hole that connects the inner and outer circumferences of the disk portion is provided at each boundary of the plurality of fan-shaped portions.

Further, in manufacturing such a brake rotor, there is provided a mold for casting a brake rotor in which an air passage is formed in a center portion in the plate thickness direction of an annular disk portion, and the brake rotor has an axial direction. And a pair of dies facing each other and having a split surface on one friction surface of the disk portion, and one of the dies forming the other friction surface and the outer peripheral surface of the disk portion is die-cut in the radial direction. Casting of a brake rotor, characterized in that it is configured to be divided so that a plurality of male dies for forming air passages project inward from the surface forming the outer peripheral surface of the disk portion in the die cutting direction. It is good to use a metal mold.

[0008]

In this way, by using a mold that is divided corresponding to each fan-shaped portion, each mold can be die-cut in the direction of the formed air passage, so there is no need to use a core. The casting process is simplified.

In particular, when the ventilation passages are formed at substantially equal intervals in parallel with the center line of the central angle of the fan-shaped portion, most of the ventilation passages can be formed so as to penetrate between the inner and outer circumferences of the disk portion. Cooling performance does not deteriorate. Further, if the ventilation passage is slightly widened on the outer peripheral side in the axial direction and the radial direction, the die cutting can be facilitated.

Further, if a hole is provided at the boundary of the fan-shaped portion so as to connect the inner and outer circumferences of the disk portion, air can flow from the inner peripheral side to the outer peripheral side of the disk portion in all the ventilation passages. Cooling performance is further improved.

Further, in such a brake rotor, when the above-mentioned mold for casting the brake rotor is used,
The mold releasing work is simplified because one of the molds that can be divided can be separated while the mold is cut in the longitudinal direction of the air passage and the other mold can be released only by cutting in the axial direction of the brake rotor. .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

1 and 2 show a brake rotor to which the present invention is applied. This brake rotor is composed of an annular disc portion 2 having a plurality of ventilation passages 1 formed in the central portion in the plate thickness direction, and an axle mounting portion 3. A shaft hole 4 is formed at the center of the mounting portion 3, and four fixing bolt holes 5 are formed around the shaft hole 4. Further, the disc portion 2 is formed with a pair of friction surfaces 6a and 6b on the front and back surfaces, with which the pads are in sliding contact.

The air passage 1 is formed by dividing the disk portion 2 into three equal parts in the circumferential direction, and each fan-shaped portion (the portion defined by the one-dot chain line in the figure).
The ventilation passages 1 in 2a, 2b, and 2c are arranged symmetrically, and are formed at equal intervals substantially parallel to the center line of the central angle of each of the fan-shaped portions 2a, 2b, and 2c. This ventilation path 1
Has a tapered shape in which the outer peripheral surface 7 side is slightly widened in the axial direction and the radial direction. Further, a radial hole 8 is provided at the boundary between the fan-shaped portions 2a, 2b and 2c so as to communicate the inner and outer circumferences of the disc portion 2.

As shown in FIG. 3, this brake rotor has a pair of upper and lower dies 10 and 10 which are opposed to each other in the axial direction of the brake rotor and have a split surface 9 on one friction surface 6a of the disk portion 2. Cast using a mold consisting of 11,
A cavity C into which the molten metal is poured is formed with the upper die 10 and the lower die 11 joined together. It should be noted that, in FIG. 3, for convenience of explanation, the upper and lower sides are reversed, and the gate is not shown.

As shown in FIG. 4, the upper die 10 is divided into three fan-shaped portions each having a central angle of 120 ° corresponding to each fan-shaped portion 2a, 2b, 2c of the disk portion 2. The upper die 10 forms the other friction surface 6b and the outer peripheral surface 7 of the disk portion 2, and as shown in FIG. 5, a plurality of inner surfaces are formed inward from the surface 12 forming the outer peripheral surface 7 in the die cutting direction. The male mold 13 for forming the air passage is provided in a protruding manner.

In the mold release after casting, the upper mold 10 is arranged such that the upper mold 10 is in the longitudinal direction of the air passage 1 with respect to the casting, that is, the fan-shaped portions 2a.
It is possible to perform die cutting by moving along the center line of the central angle of b · 2c. The lower die 11 is punched upward, that is, in the axial direction of the brake rotor.

In the brake rotor thus separated from the mold, the ribs 14 of the fan-shaped portions adjacent to each other are connected at the boundary portion of the fan-shaped portions 2a, 2b, 2c. Therefore, radial holes 8 are bored in the ribs 14 in order to further improve the cooling performance. As a result, air can flow from the inner peripheral side to the outer peripheral side of the disk portion 2 in all the ventilation paths 1.

In the first and second embodiments, the ventilation passage 1 is symmetrically formed in the fan-shaped portion formed by dividing the disk portion into three parts, but the present invention is not limited to such division into three parts. Instead, for example, it may be divided into four or more.

[0020]

As is apparent from the above description, according to the brake rotor and the casting mold thereof according to the present invention,
It is possible to perform casting without using a core, and it is possible to achieve a great effect in simplifying the manufacturing process and reducing the manufacturing cost while ensuring the cooling efficiency.

Further, in this case, since the lengths of the air passages are different, the standing wave is suppressed, and there is also a secondary effect that noise is reduced.

[Brief description of drawings]

FIG. 1 is a plan view showing a brake rotor to which the present invention is applied.

FIG. 2 is a vertical sectional view showing the brake rotor shown in FIG. 1 along a line II-II.

FIG. 3 is a vertical cross-sectional view showing a state in which an upper die and a lower die of the mold are joined together.

FIG. 4 is a plan view (IV-IV arrow view) showing the upper mold shown in FIG. 3.

5 is a perspective view showing one of the upper mold halves shown in FIG.

[Explanation of symbols]

 1 Ventilation path 2 Disk part 2a / 2b / 2c Fan-shaped part 3 Mounting part 4 Shaft hole 5 Bolt hole 6 Friction surface 7 Outer peripheral surface 8 Radial hole 9 Dividing surface 10 / 10a / 10b / 10c Upper mold 11 Lower mold 12 Surface 13 Male 14 for air passage formation

Claims (4)

[Claims] 1. A brake rotor in which an air passage is formed at a central portion in the plate thickness direction of an annular disc portion, wherein each air passage divides the disc portion into a plurality of circumferential portions. In the brake rotor, a plurality of brake rotors are formed substantially parallel to the radial direction. 2. The air passages are formed in each of the plurality of fan-shaped portions in the same arrangement at substantially equal intervals substantially parallel to the median line of the central angle of the fan-shaped portions, and the outer peripheral side is in the axial direction. The brake rotor according to claim 1, wherein the brake rotor is widened in the radial direction. 3. The brake rotor according to claim 1, wherein each of the boundary portions of the plurality of fan-shaped portions is provided with a hole that communicates the inner and outer circumferences of the disc portion. 4. A mold for casting a brake rotor in which an air passage is formed at a center portion in the plate thickness direction of an annular disc portion, the die being opposed to each other in the axial direction of the brake rotor, and one of the disc portions. Of a pair of dies having a dividing surface on the friction surface of the disk portion, and one of the dies forming the other friction surface and the outer peripheral surface of the disk portion is configured to be dividable for radial die cutting, A mold for casting a brake rotor, characterized in that a plurality of male molds for forming air passages are provided so as to project inward from the surface forming the outer peripheral surface of the disk portion in the mold cutting direction.