JPH02209632A - Rotor for ventilated disk brake - Google Patents

Abstract

PURPOSE:To reduce weight, to improve cooling efficiency and to facilitate manufacture by providing vent holes with a circular cross section by means of linearly communicating the outer circumferential end side and the inner circumferential end side of a solid rotor in the doughnut shape through drill machining. CONSTITUTION:A groove 4 which opens to one end is formed on the whole circumference of the inner circumferential end side of a rotor 1. Numerous vent holes 5 which communicates from the outer circumferential end to the groove 4 are linearly provided in the thickness of the rotor 1. These vent holes 5 are provided by drill machining from the outer circumferential surface toward the inner circumferential surface of the solid rotor 1. In this way, weight of the rotor can be reduced and cooling efficiency can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotor used in a ventilated disc brake of a motorcycle or the like.

[Prior Art] A rotor for ventilated disc brakes that has a large number of radial ventilation holes formed in the radial direction of the rotor to improve the heat dissipation effect is known (for example,
(Refer to Publication No.-7408).

Such rotors for ventilated disc brakes are generally manufactured by casting, and ventilation holes are integrally formed during the casting process. The cross-sectional shape of this ventilation hole is generally oval or rectangular, and the cross-sectional area is increased to increase the amount of ventilation.

[Problems to be Solved by the Invention] Incidentally, in order to improve the cooling efficiency of the rotor, it is conceivable to increase the amount of ventilation by increasing the number of ventilation holes or the like. For this reason, it is desirable to make the wall thickness between adjacent ventilation holes as thin as possible. However, there is a limit to the wall thickness between the vent holes due to casting technology, and as a result, the degree of freedom in designing the vent holes is limited and the device is relatively heavy. In addition, unevenness due to the casting surface was created inside the ventilation hole, which caused ventilation resistance. Furthermore, in order to form the ventilation holes, it was necessary to use a core during casting, which increased the number of molding steps.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a rotor for ventilated disc brakes that is lightweight, has good cooling performance, and is easy to manufacture.

[Means for Solving the Problems] In order to solve the above problems, a ventilated disc brake rotor according to the present invention forms a donut-shaped solid rotor, and drills the outer peripheral end side and the inner peripheral end side of the rotor. It is characterized by having ventilation holes with a circular cross section that communicate linearly with each other.

[Operation of the Invention] When a ventilation hole that communicates between the outer peripheral end and the inner peripheral end is drilled into a codonut-shaped solid rotor, the ventilation hole is formed with a circular cross section and the adjacent ventilation holes The wall thickness between the parts can be made thinner than when it is cast, making it possible to increase the number of ventilation holes and making it lighter.

Furthermore, since the unevenness on the inner surface of the vent hole is reduced, the ventilation resistance is reduced and the diameter can be reduced. Moreover, since the cross section of the ventilation hole is circular, the cross-sectional area of the ventilation hole is larger than that in the case of other cross-sectional shapes. Therefore, by forming a large number of small-diameter ventilation holes, the amount of ventilation increases and the cooling efficiency improves.

[Example code] An embodiment of the present invention is shown in FIGS. 1 to 3.

FIG. 1 is a view showing approximately one-third of the side surface shape of a rotor 1 formed by casting, and a protrusion 2 is integrally formed on the inner circumferential end of the rotor 1 to protrude toward the center. He is installed floating.

A groove 4 that opens to one side all around the inner circumference of the rotor 1
is formed. A large number of ventilation holes 5 are linearly bored in the thickness of the rotor 1 and communicate with the grooves 4 from the outer peripheral end thereof. Note that the ventilation holes 5 are formed with a slight inclination with respect to the radial direction in order to improve the air guiding effect.

This vent hole 5 is a predecessor of the rotor 1, and is formed by drilling from the outer peripheral surface to the inner peripheral surface of the solid rotor after casting a solid rotor in which no ventilation holes have been formed yet. As a result, the ventilation hole 5 has a circular cross section, one end opening into the outer peripheral surface of the rotor 1, and the other end communicating with the groove 4. As shown in FIGS. 1 and 2, the ventilation holes 5 are formed at equal pitches, and are also formed on the outer peripheral side of the protrusion 2.

Since the protrusion 2 is a part where stress is concentrated, it is formed relatively thick and protrudes to one side so as to cover the opening of the ventilation hole 5, as shown in FIG. 4 is formed.

Next, the operation of this embodiment will be explained. When the rotor 1 rotates in the direction of arrow C, cooling air enters the ventilation hole 5 from the inner circumferential side. Further, the protrusion 2 portion first enters the groove 4 as shown by the arrow, and then enters the vent hole 5 on the outer circumferential side of the protrusion 2 communicating with the groove 4, so that the entire rotor 1 is uniformly cooled. At this time, since the ventilation holes 5 are formed by drilling, the wall thickness between adjacent ventilation holes 5 becomes thinner, and the number of ventilation holes 5 increases accordingly. Therefore, the rotor l is lightweight and has improved cooling efficiency. Further, since the ventilation hole 5 has a circular cross section by drilling, the cross-sectional area of the ventilation hole 5 is made as large as possible. Moreover, since the inner surface of the vent hole 5 has fewer irregularities than the casting surface, the ventilation resistance is reduced. Therefore, in these respects as well, the amount of ventilation increases and the cooling efficiency increases.

Moreover, in this embodiment, since the groove 4 is formed on the base side of the protrusion 2, even if the relatively thick protrusion 2 for floating mounting is provided, the cooling air can flow through the ventilation hole 5 on the outer peripheral side of the protrusion 2. This makes it possible to uniformly cool the entire rotor 1, making it difficult for thermal deformation due to uneven cooling to occur.

Furthermore, the present invention is not limited to the above embodiments, and various applications and modifications are possible. For example, as shown in FIG. 4, by arranging the ventilation holes 5 in a staggered manner, the distribution density can be increased and the number thereof can be increased. Further, as shown in FIG. 5, the pitches and hole diameters can be made random, such as by arranging the large-diameter ventilation holes 5a and the small-diameter ventilation holes 5b alternately or by forming them at uneven pitches. Furthermore, as shown in FIG. 6, a tapered vent hole 5c can be used to make the vent hole 5c thinner.

[Effects of the Invention] Since the ventilation holes according to the present invention are formed by drilling into the solid rotor, the wall thickness between adjacent ventilation holes can be made as thin as possible, and as a result, the rotor can be made lighter. At the same time, the cooling efficiency can be improved by increasing the number of ventilation holes and increasing the amount of ventilation. Moreover, the cooling efficiency is further increased because the cross section is made circular to maximize the cross-sectional area of ventilation, and the inner surface is smoothed by drilling to reduce ventilation resistance. Further, since a core during casting is not required as in the conventional method, manufacturing is also facilitated.

[Brief explanation of the drawing]

1 to 3 show one embodiment, FIG. 1 is a partially cutaway side view of the rotor, FIG. 2 is an enlarged partial view in the direction of the arrow A in FIG. 1, and FIG. It is an enlarged sectional view along the BB line of a figure. FIG. 4 is a view similar to FIG. 2 showing another embodiment, and FIGS. 5 and 6 are partial sectional views of rotors according to other embodiments. (Explanation of symbols) 1...Rotor, 2...Protrusion, 3...Hub, 4...
・Groove, 5...Vent hole. The first re

Claims (1)

[Claims] A rotor for a ventilated disc brake, characterized in that a donut-shaped solid rotor is formed, and a ventilation hole having a circular cross section is formed by drilling the outer peripheral end side and the inner peripheral end side thereof into linear communication.