JP2007192350A - Disc rotor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of reducing braking force, since a friction coefficient of a sliding surface reduces, when moisture sticks between a brake pad and the disc rotor sliding surface. <P>SOLUTION: This disc rotor 10 is a ventilated type disc rotor having a pair of opposed outer side sliding plate 12 and inner side sliding plate 14, a plurality of fins 20 radially arranged between the pair of sliding plates and a plurality of ventilation holes 30 defined by the pair of sliding plates and the fins 20. A venturi part 26 is formed between an inner peripheral side opening part and an outer peripheral side opening part of a ventilation hole 30a. The venturi part 26 is formed with a communicating hole 22 communicating the sliding surface 12a of the outer side sliding plate 12 with the inside of the ventilation hole 30a and a communicating hole 24 communicating the sliding surface 14a of the inner side sliding plate with the inside of the ventilation hole 30a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a disc rotor used in a vehicle disc brake device.

  2. Description of the Related Art Conventionally, ventilated disk rotors are known as disk rotors used in vehicle disk brake devices (for example, Patent Document 1). In order to improve the cooling performance of the disk rotor, a plurality of ventilation holes penetrating from the inner circumference side to the outer circumference side of the disk rotor are formed.

  When such a ventilated disc rotor rotates, the air in the ventilation hole is discharged to the outside from the outer peripheral side opening by centrifugal force. As a result, the inside of the ventilation hole is in a negative pressure state, and external air is taken in from the inner peripheral side opening of the ventilation hole, whereby an air flow is created in the disk rotor, and the disk rotor can be cooled.

Patent Document 2 proposes a ventilated type disk rotor in which a venturi is formed in the ventilation hole by changing the thickness of the sliding plate, and the cooling action is increased by increasing the air flow rate. Yes.
JP-T-2004-526924 JP 2000-501383 A

  By the way, in the disc brake device, if moisture adheres between the brake pad and the disc rotor sliding surface, there is a problem that the braking force is reduced because the friction coefficient of the sliding surface is lowered.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a disc rotor that can reduce moisture adhering to a sliding surface.

  In order to solve the above problems, a disk rotor according to an aspect of the present invention includes a pair of opposed sliding plates, a plurality of fins radially disposed between the pair of sliding plates, and a pair of sliding plates. A ventilated type disk rotor having a plurality of ventilation holes defined by fins, wherein a venturi is formed between an inner circumferential side opening and an outer circumferential side opening of the ventilation hole, In the venturi portion, a communication hole that connects the sliding surface of the sliding plate and the inside of the ventilation hole is formed.

  According to this aspect, when the disk rotor rotates together with the rotation of the wheel, air flows in the ventilation hole from the inner peripheral side to the outer peripheral side of the disk rotor. The flow velocity of air in the vent hole in which the venturi portion is formed is the highest in the venturi portion. As a result, the pressure in the ventilation hole is lowest in the venturi portion. When the pressure in the venturi portion decreases, air flows into the ventilation hole through the communication hole from the sliding surface side of the sliding plate. The air flowing into the ventilation hole through the communication hole is discharged from the outer peripheral side opening to the outside of the disk rotor together with the air flowing from the inner peripheral opening of the ventilation hole. When moisture adheres to the sliding surface, the air flows in this manner, whereby moisture is sucked into the ventilation hole through the communication hole and discharged from the opening on the outer peripheral side of the ventilation hole. As a result, the amount of water adhering to the sliding surface can be reduced, so that a decrease in the friction coefficient of the sliding surface is suppressed, and the braking force of the disc brake device can be improved. Further, since a new air flow from the sliding surface to the inside of the ventilation hole occurs, the cooling performance of the disk rotor can be improved.

  The venturi may be formed by a curved side surface of the fin. Moreover, a venturi part may be formed by making the curved convex surface of an adjacent fin oppose. When the venturi portion is formed by using the curved surface of the fin, the weight of the disk rotor can be reduced as compared with the case where the venturi portion is formed by changing the thickness of the sliding plate.

  According to the present invention, moisture adhering to the sliding surface of the disk rotor can be reduced.

  The structure of the disk rotor 10 according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a partially broken front view of a disk rotor 10 according to the present embodiment. 2 is a cross-sectional view taken along the line AA of the disk rotor 10 shown in FIG.

  As shown in FIGS. 1 and 2, the disc rotor 10 includes an outer side sliding plate 12 disposed on the outer side in the vehicle width direction, and faces the outer side sliding plate 12 in parallel to the inner side in the vehicle width direction. And an inner side sliding plate 14 disposed. The center part of the outer side sliding plate 12 and the inner side sliding plate 14 is greatly opened, and a hat portion 40 used for attachment to the axle is formed on the inner peripheral edge of the outer side sliding plate 12. Is provided. The bottom plate portion of the hat portion 40 is provided with a plurality of bolt holes 42 for inserting bolts.

  A plurality of fins 20 are arranged radially between the pair of outer side sliding plate 12 and inner side sliding plate 14, and the outer side sliding plate 12 and the inner side sliding plate 14 are coupled to each other. Yes. The plurality of fins 20 and the pair of outer side sliding plate 12 and inner side sliding plate 14 form a plurality of ventilation holes 30 that extend radially from the inner peripheral side to the outer peripheral side of the disk rotor 10. ing. In the disc rotor 10 shown in FIG. 1, 40 fins are arranged at substantially equal intervals (360/40 = 9 degrees) in the circumferential direction, and therefore 40 ventilation holes 30 (some are not shown). Is formed.

  In the disk rotor 10 according to the present embodiment, among the 40 vent holes 30 formed, the eight vent holes 30a (not shown in part) selected at intervals of 45 degrees have a cross-sectional area of the vent holes. A narrowed venturi portion 26 is formed.

  The venturi portion 26 is formed by curving the side surfaces of adjacent fins 20a and 20b that form the ventilation hole 30a and making the curved convex surfaces 18 face each other. The width of the peripheral method of the fin 20a and the fin 20b is substantially the same as the width of the fin 20 formed in a straight line other than the fin 20a and the fin 20b. By forming the fins 20a and 20b in such a shape, the cross-sectional area of the ventilation hole 30a gradually decreases from the inner peripheral side opening of the ventilation hole 30a to the venturi part 26, and becomes the smallest in the venturi part 26. Yes. And it becomes large gradually from the venturi part 26 to the outer peripheral side opening part of the ventilation hole 30a.

  As shown in FIG. 2, in the disk rotor 10 according to the present embodiment, in the venturi portion 26, the communication hole 22 that connects the sliding surface 12 a of the outer side sliding plate 12 and the inside of the ventilation hole 30 a, and the inner side A communication hole 24 that connects the sliding surface 14a of the sliding plate 14 and the inside of the ventilation hole 30a is formed.

  The configuration of the disk rotor 10 according to the present embodiment has been described above. Next, the operation of the disk rotor 10 configured as described above will be described. 3 and 4 are views showing a state in which air flows in the ventilation holes of the disk rotor 10. FIG. 3 is an enlarged view of a part of the front view shown in FIG. FIG. 4 is an enlarged view of a part of the cross-sectional view shown in FIG. In FIG. 3 and FIG. 4, the air flow is represented by arrows.

  When the disk rotor 10 rotates in the ω direction together with the rotation of the wheel (not shown), the air in the ventilation hole 30 is discharged to the outside from the outer peripheral side opening of the ventilation hole 30 by centrifugal force. When the air in the ventilation hole 30 is discharged to the outside, the inside of the ventilation hole 30 is in a negative pressure state, and external air is taken in from the inner peripheral side opening of the ventilation hole 30. Thus, when the disk rotor 10 rotates, an air flow from the inner peripheral side to the outer peripheral side of the disk rotor 10 is created as shown in FIG.

  Here, when attention is paid to the flow velocity of air in the vent hole 30a in which the venturi portion 26 is formed, the flow velocity of air taken in from the inner peripheral side opening of the vent hole 30a is the highest in the venturi portion 26, and then decelerates. To do. From Bernoulli's theorem, the pressure decreases as the flow velocity increases, and therefore the pressure is the lowest in the venturi section 26 in the vent hole 30a.

  In the disk rotor 10 according to the present embodiment, since the communication hole 22 is provided in the venturi portion 26, when the pressure of the venturi portion 26 decreases, the sliding of the outer side sliding plate 12 is performed as shown in FIG. Air flows into the ventilation hole 30a through the communication hole 22 from the moving surface 12a side. Similarly, air flows from the sliding surface 14 a side of the inner side sliding plate 14 into the ventilation hole 30 a through the communication hole 24. The air that has flowed into the ventilation hole 30a through the communication holes 22 and 24 is discharged to the outside from the outer circumferential side opening together with the air that has flowed from the inner circumferential side opening of the ventilation hole 30a.

  As described above, in the disk rotor 10 according to the present embodiment, the communication hole 22 and the communication hole 24 are formed in the venturi portion 26 where the pressure in the ventilation hole 30a is the lowest. The efficiency of sucking the air on the sliding surface side can be increased as compared with the case of making it.

  When moisture has adhered to the sliding surfaces 12a and 14a, the moisture that has adhered to the sliding surface is sucked into the ventilation holes 30a through the communication holes 22 and 24 when the air flows in this manner. It is discharged from the outer peripheral side opening of the ventilation hole 30a. As a result, the amount of moisture adhering to the sliding surfaces 12a and 14a is reduced, so that a decrease in the friction coefficient of the sliding surfaces 12a and 14a is suppressed, and the braking force of the disc brake device can be improved.

  Further, since a new air flow from the sliding surfaces 12a and 14a toward the inside of the ventilation hole 30a occurs, the cooling performance of the disk rotor 10 can be enhanced.

  Further, according to the disk rotor 10 according to the present embodiment, it is not necessary to change the structure of the disk brake device itself, so that it can be easily applied to an existing disk brake device.

  When the venturi portion is formed by changing the thickness of the outer side sliding plate or the inner side sliding plate, the weight of the disc rotor may be increased. According to the disk rotor 10 according to the present embodiment, the venturi portion 26 is formed by curving the side surface of the fin that defines the ventilation hole, and therefore the outer side sliding plate 12 or the inner side sliding plate 14. It is not necessary to change the thickness of the disk rotor, and the weight of the disk rotor 10 can be reduced as compared with the case where the venturi portion is formed by changing the thickness of the sliding plate.

  The present invention has been described above based on the embodiment. It should be understood by those skilled in the art that these embodiments are exemplifications, and that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention.

  For example, in the above-described embodiment, the number of fins formed between the pair of outer side sliding plates and the inner side sliding plates is 40, but the number of fins is not limited thereto. In the embodiment, eight vent holes forming the venturi portion are formed at intervals of 45 degrees, but the number is not limited to this. When the number of ventilation holes forming the venturi portion is increased, water adhering to the sliding surface can be more effectively removed.

  In the embodiment, all the venturi portions are formed on the same circle, but the venturi portions may be alternately formed on the inner peripheral side and the outer peripheral side of the disk rotor. In this case, moisture adhering to the inner peripheral side and the outer peripheral side of the disk rotor sliding surface can be efficiently removed.

It is a partially broken front view of the disk rotor which concerns on this Embodiment. It is AA sectional drawing of the disc rotor shown in FIG. It is a figure which shows a mode that air flows through the ventilation hole of a disk rotor. It is a figure which shows a mode that air flows through the ventilation hole of a disk rotor.

Explanation of symbols

  10 disk rotor, 12 outer side sliding plate, 12a, 14a sliding surface, 14 inner side sliding plate, 18 curved convex surface, 20 fin, 22, 24 communication hole, 26 venturi portion, 30 vent hole, 40 hat portion, 42 Bolt hole.

Claims (3)

A pair of opposed sliding plates, a plurality of fins radially disposed between the pair of sliding plates, and a plurality of ventilation holes defined by the pair of sliding plates and the fins A ventilated disc rotor,
A venturi part is formed between the inner peripheral side opening and the outer peripheral side opening of the ventilation hole, and a communication hole is formed in the venturi part to communicate the sliding surface of the sliding plate and the inside of the ventilation hole. A disc rotor characterized by that.   The disk rotor according to claim 1, wherein the venturi portion is formed by a curved side surface of the fin.   The disk rotor according to claim 1, wherein the venturi portion is formed by opposing curved convex surfaces of adjacent fins.

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