JP2024056215A - Brake disc rotor and vehicle equipped with same - Google Patents

Abstract

[Problem] To provide a brake disc rotor with improved cooling performance without being subject to significant restrictions on manufacturing method, materials, etc. [Solution] A brake disc rotor having a disc portion having a first surface and a second surface, a plurality of substantially radial fins formed on at least one of the first surface and the second surface of the disc portion from the center of rotation of the disc toward the outer edge of the disc, and apexes formed on the fins to serve as sliding surfaces. [Selected drawing] Figure 1

Description

This disclosure relates to a brake disc rotor and a vehicle equipped with the same.

Various brake disc rotor configurations have been proposed to improve various performance aspects, such as cooling performance.

For example, Patent Document 1 discloses a brake disc configuration that combines multiple discs with fins to achieve both friction damping and cooling performance.

Patent document 2 also discloses a configuration in which notches of different sizes are made in a roughly cylindrical connecting portion that connects the disk portion and the flange portion in a solid disk rotor composed of a disk portion and a hat portion.

Patent document 3 discloses a rotor for a disc brake that has multiple holes that penetrate from the outer surface to the inner surface of the rotor.

Patent document 4 discloses a configuration in which, in a solid-type disc rotor, a low-rigidity section is provided at the boundary between the sliding section and the connecting section, so that when axial vibration occurs in the disc rotor, the low-rigidity section shows a large displacement as the antinode of the vibration, quickly attenuating the vibration caused by the pressure contact of the brake pads, and effectively suppressing brake squeal.

JP 2018-021614 A JP 2001-234956 A JP 2000-145842 A Japanese Patent Application Laid-Open No. 10-089388

To improve cooling performance, brake rotors known as ventilated discs are known. Generally, ventilated discs have a hollow structure with cooling paths inside two discs. A disadvantage of ventilated discs is that there is an upper limit to the size of the cooling path due to the balance between cooling performance and heat capacity. Furthermore, ventilated discs are manufactured as a single piece from cast iron from the standpoint of balancing cost and shape, which also has the disadvantage of restricting the materials that can be used.

However, as mentioned in the above-mentioned prior art documents, there are still problems to be solved with conventional solid-type disc rotors. In other words, conventional solid-type disc rotors have not yet satisfied the demands of users in terms of cooling performance.

This disclosure was made in consideration of the above-mentioned problems, and aims to provide a brake disc rotor with excellent cooling performance and with few major restrictions on manufacturing methods and materials.

To solve the above problem, the brake disc rotor in one embodiment of the present disclosure is characterized by having a disc portion having a first surface and a second surface, a plurality of radial fins formed on at least one of the first surface and the second surface of the disc portion from the center of rotation toward the outer edge of the disc, and a ridge formed on the fin that serves as a sliding surface.

This disclosure makes it possible to provide a brake disc rotor with improved cooling performance without being subject to significant constraints on manufacturing methods, materials, etc.

1 is a perspective view of a brake disc rotor according to an embodiment of the present invention, as viewed from the inside of a vehicle. 1 is a perspective view of a brake disc rotor according to an embodiment of the present invention, as viewed from outside a vehicle. 2 is a front view of the brake disc rotor according to the embodiment to which a brake caliper and a dust cover are attached, as viewed from outside the vehicle. FIG. This is a cross-sectional view taken along line A-A' in Figure 3. This is a cross-sectional view taken along line B-B' in Figure 3. FIG. 11 is a perspective view of a brake disc rotor according to another embodiment, as viewed from the inside of a vehicle. FIG. 11 is a perspective view of a brake disc rotor according to another embodiment, as viewed from outside the vehicle. 13 is a front view of a brake disc rotor according to another embodiment to which a brake caliper and a dust cover are attached, as viewed from outside the vehicle. FIG. This is a cross-sectional view of A-A' in Figure 8. 9 is another example of a cross-sectional view taken along line A-A' in FIG. 8. This is a cross-sectional view taken along line B-B' in Figure 8.

Next, a preferred embodiment of the present disclosure will be described. Note that in all drawings of the following embodiments, the same or corresponding parts are given the same reference numerals. Furthermore, the present disclosure is not limited to the embodiments described below.

First Embodiment
A brake disc rotor 100 according to the present disclosure will be described. FIGS. 1 to 5 show a brake disc rotor 100 according to an embodiment of the present disclosure. FIG. 1 is a perspective view of the brake disc rotor 100 as viewed from inside the vehicle 1. FIG. 2 is a perspective view of the brake disc rotor 100 as viewed from outside the vehicle 1. FIG. 3 is a front view of the brake disc rotor 100 as viewed from outside the vehicle 1 when a brake caliper and a dust cover are attached to the brake disc rotor 100. FIG. 4 is an A-A' cross-sectional view in FIG. 3, and FIG. 5 is a B-B' cross-sectional view in FIG. 3. In FIG. 3, the front side of the paper shows the outside of the vehicle. Also, the A-A' line in FIG. 3 overlaps with a diameter passing through the center of rotation O, and is a line that forms a cross section of two fin grooves 22d that face each other with the center of rotation O as the center. In FIGS. 4 and 5, the top of the paper shows the outside of the vehicle, and the bottom of the paper shows the inside of the vehicle.

The brake disc rotor 100 is fixed to a vehicle hub (not shown) on the inside of a vehicle wheel. The brake disc rotor 100 is used in a vehicle disc brake and has a hat portion 21 that is attached to the vehicle hub via a known bolt or the like, and a flat disc portion 22 that extends in a ring shape around the hat portion 21. The hat portion 21 and the disc portion 22 may be integrally formed, or may be connected to each other by a fixing pin or bolt (not shown). The disc portion 22 has a first surface 22a and a second surface 22b. As shown in FIG. 1, the brake disc rotor 100 can be attached to a vehicle so that the first surface 22a is on the inside of the vehicle and the second surface 22b is on the outside of the vehicle.

Regarding the braking function of the brake disc rotor 100, the hat portion 21 is connected to the vehicle hub, and the brake pads of the brake caliper attached to the vehicle are pressed against the vehicle inner surface (first surface) 22a and the vehicle outer surface (second surface) 22b of the disc portion 22, generating friction between the brake pads and the first surface 22a and the second surface 22b, thereby generating a braking force for the vehicle.

The disk portion 22 is formed using cast iron or carbon. The hat portion 21 may be formed using the same type of metal material as the disk portion 22, or may be formed using a metal different from the disk portion 22, such as aluminum or stainless steel. As an example, the size of the brake disk rotor 100 is such that the outer diameter (diameter) of the disk portion 22 is 300 to 400 mm, the diameter (inner diameter) of the hat portion 21 is approximately 250 mm, and the thickness of the disk portion 22 is 4 to 30 mm, but is not limited to these.

In this embodiment, both sides of the disk portion 22 have different planar shapes. That is, as shown in FIG. 1, the surface 22a (first surface) on the inside of the vehicle is uneven. On the other hand, the surface 22b (second surface) on the outside of the vehicle is not uneven.

To explain more specifically the shape of the vehicle-inner surface 22a of the disk portion 22, multiple radial fins 22c are formed from the rotation center O of the disk portion 22 toward the outer edge. The apex of each fin 22c forms a fin sliding surface 22e. Fin grooves 22d are formed between multiple adjacent fins 22c.

(Fin 22c)
In this embodiment, as described above, a plurality of fins 22c are formed radially from the rotation center O toward the outer edge in the disk portion 22. The fins 22c have a function of dissipating heat from the surface of the disk portion 22 by expanding the heat transfer area. In the figure, 24 fins 22c are formed, but this is not limited to this. In the figure, the fins 22c are formed at equal intervals, but they may be unequal. Furthermore, the fins 22c are formed in a linear shape along the radial direction, but this is not limited to this, and they may have a curved shape such as a spiral or a wavy shape. The width of the fins 22c may be the same width from the rotation center O toward the outer edge, or the width may be different.

(Fin sliding surface 22e)
As described above, the apex of the fin 22c is a surface having a predetermined width, forming the fin sliding surface 22e. The fin sliding surface 22e has a function of braking the vehicle by contacting the brake pad of the brake caliper and converting kinetic energy into thermal energy through friction. As shown in FIG. 5, the fin sliding surface 22e is a surface that is approximately parallel to the second surface 22b of the disk portion 22. The width of the fin sliding surface 22e and the central angle _θ1 formed by both ends of the arc of one fin sliding surface 22e and the rotation center O of the disk portion 22 can be appropriately changed depending on the number of the fins 22c formed, etc.

(Fin groove 22d)
As described above, the fin groove 22d is formed between a plurality of adjacent fins 22c. Specifically, the fin groove 22d is formed by the side surfaces of the adjacent fins 22c and the surface connecting the lowest ends of the side surfaces. The cross section of the fin groove 22d perpendicular to the longitudinal direction has an upwardly convex U-shape as shown in FIG. 5 and the like, but is not limited thereto and may be a dome shape or the like. The number of fin grooves 22d formed on the first surface 22a is not particularly limited and can be appropriately set according to the number of fins 22c formed, etc. In the figure, the fin grooves 22d are formed at equal intervals, but may be unequal. Furthermore, in the figure, the width of the fin groove 22d is equal from the rotation center O of the disk portion 22 to the outer edge, but is not limited thereto. There is no particular limit to the depth of the fin groove 22d, and it can be appropriately set according to the height of the fin 22c, etc.

When braking the brake disc rotor 100, the brake pads of the brake caliper can come into contact with both the fin sliding surface 22e and the sliding surface 22b (second surface). On the other hand, the brake pads do not come into direct contact with the fin grooves 22d.

The fin grooves 22d function as flow paths for cooling air as the surrounding air enters due to the rotation of the brake disc rotor 100. Specifically, the fin grooves 22d allow the wind generated by the rotation of the brake disc rotor 100 to flow as cooling air through the inside of the fin grooves 22d from the center of rotation O of the disc portion 22 toward the outer edge (see FIG. 4).

(First embodiment: air flow during rotor rotation)
The flow of cooling air when the brake disc rotor 100 of this embodiment rotates will be described below.

As the vehicle travels, the brake disc rotor 100 rotates in the direction of travel. The air around the brake disc rotor 100 moves as the brake disc rotor 100 rotates. In particular, the air inside the fin groove 22d is released toward the outer edge due to the centrifugal force of the rotation. Then, the air pressure near the rotation center O of the disc portion 22 drops, so air flows from the inside of the vehicle toward the vicinity of the rotation center O of the disc portion 22. In this way, air flows inside the fin groove 22d from the vicinity of the rotation center O of the disc portion 22 toward the outer edge. The air flowing inside the fin groove 22d moves while absorbing heat from the disc portion 22 and is released to the outside of the vehicle, so that the brake disc rotor 100 of this embodiment can be effectively cooled.

As shown in Figures 3 to 5, the brake disc rotor 100 of this embodiment can be used in combination with a dust cover DC. In this case, the flow path of the cooling air is surrounded by the fin groove 22d and the dust cover DC. Then, as the brake disc rotor 100 rotates, the air (cooling air) in the fin groove 22d moves through the flow path from the center of rotation toward the outer edge.

(Effects of the First Embodiment)
The effects of using the brake disc rotor 100 of this embodiment alone are as follows. The air flowing through the inside of the fin grooves 22d moves while absorbing heat from the disc portion 22 and is discharged to the outside of the vehicle, improving the cooling performance. In addition, the improved cooling performance of the brake disc rotor 100 reduces heat transfer to the piston side of the vehicle engine, suppressing the paper lock phenomenon. Furthermore, the brake disc rotor 100 of this embodiment can discharge gas generated by thermal decomposition of the brake pad friction material toward the outer edge of the disc portion 22 together with the cooling air. This makes it possible to suppress the fade phenomenon.

In addition, since the brake disc rotor 100 of this embodiment is a solid disc, it can be manufactured at a lower cost than a hollow structure. Also, since it does not need to be hollow, manufacturing methods other than casting can be applied. Furthermore, as mentioned above, the gas generated by the thermal decomposition of the brake pad friction material can be released outside the vehicle together with the cooling air, which provides a cleaning effect for the pad surface after the fade phenomenon.

The effect of using the brake disc rotor 100 of this embodiment in combination with the dust cover DC is as follows. By using the brake disc rotor 100 in combination with the dust cover DC, a flow path for cooling air is formed between the brake disc rotor 100 and the dust cover DC. In other words, there is an advantage that a cooling effect similar to that of a conventional ventilated type disc can be obtained using a solid disc that does not have a hollow structure. In addition, in this embodiment, the air in the fin groove 22d that absorbs the heat from the brake disc rotor 100 also comes into contact with the surface of the dust cover DC. Therefore, the heat of the brake disc rotor 100 can be indirectly transferred to the dust cover DC, and the dust cover itself functions as a heat sink. In this way, by combining the brake disc rotor 100 with the dust cover DC, the cooling performance can be further improved.

The brake disc rotor 100 has been described above as an example in which the fins 22c are formed on the surface 22a (first surface) on the inside of the vehicle, but this embodiment is not limited to this. That is, the brake disc rotor 100 of this embodiment may have the fins 22c formed on the surface 22b (second surface) on the outside of the vehicle, and may have no fins formed on the surface 22a (first surface) on the inside of the vehicle. However, from the viewpoint of forming a cooling air flow path in cooperation with a dust cover that is usually arranged on the inside of the vehicle of the brake disc rotor, it is more preferable that the fins 22c are formed on the surface on the inside of the vehicle.

Second Embodiment
Next, a brake disc rotor 200 according to a second embodiment of the present disclosure will be described with reference to Figures 6 to 10. The brake disc rotor 200 according to the second embodiment differs from the first embodiment described above in that fins are formed on both sides of the disc portion 22. Therefore, the above differences will be mainly described, and components common to the first embodiment described above will be denoted by common reference numerals and their description will be omitted.

Figure 6 is a perspective view of the brake disc rotor 200 of the second embodiment as seen from inside the vehicle. Figure 7 is a perspective view of the brake disc rotor 200 of the second embodiment as seen from outside the vehicle. Figure 8 is a front view of the brake disc rotor 200 of the second embodiment with a brake caliper and dust cover attached as seen from outside the vehicle. Figure 9 is a cross-sectional view taken along line A-A' in Figure 8. Figure 10 is a cross-sectional view taken along line B-B' in Figure 8. Note that the front of the page in Figure 8 shows the outside of the vehicle. Line A-A' in Figure 8 overlaps with a diameter passing through the center of rotation O, and is a line that forms a cross section of two fin grooves 22o that face each other around the center of rotation O. In Figures 9 and 10, the top of the page shows the outside of the vehicle, and the bottom of the page shows the inside of the vehicle.

As shown in FIG. 6, the first surface 22a on the vehicle inner side is formed with a plurality of substantially radial fins 22c extending from the rotation center O of the disk portion 22 toward the outer edge, as in the first embodiment described above. The apexes of the fins 22c form the fin sliding surface 22e.

On the other hand, as shown in FIG. 7, a plurality of substantially radial fins 22m are formed on the second surface 22b on the outer side of the vehicle, extending from the rotation center O of the disk portion 22 toward the outer edge. The apex of the fins 22m forms a fin sliding surface 22n. Fin grooves 22o are formed between the adjacent fins 22m.

(Fin 22m)
In the brake disc rotor 200 of this embodiment, the fins 22m are formed in a plurality of substantially radial directions from the rotation center O to the outer edge in the disk portion 22, similar to the fins 22c on the first surface. The fins 22m also have a function of dissipating heat from the surface of the disk portion 22 by expanding the heat transfer area, similar to the fins 22c. In the figure, 24 fins 22m are formed, but this is not limited to this. In the figure, the fins 22m are formed at equal intervals, but they may be unequal. Furthermore, the fins 22m are formed in a straight line along the radial direction, but this is not limited to this, and they may have a shape such as a spiral curve or a wave shape. The width of the fins 22m may be the same width from the rotation center O to the outer edge, or the width may be different. In addition, the fins 22c and the fins 22m may have the same shape or different shapes.

In this embodiment, the fins 22m formed on the surface 22b (second surface) on the outer side of the vehicle are out of phase with the fins 22c formed on the opposite surface 22a (first surface). That is, as shown in FIG. 7, a fin groove 22d is disposed on the opposite side (first surface side) of any fin 22m. Note that in this embodiment, it is not necessary for all fins 22m to be out of phase with the fins 22c on the first surface, and it is sufficient that at least one fin 22m is out of phase with the fin 22c.

(Fin sliding surface 22n)
The apex of the fin 22m is a surface having a predetermined width, forming a fin sliding surface 22n. The fin sliding surface 22n has a function of braking the vehicle by contacting the brake pad of the brake caliper and converting kinetic energy into thermal energy by friction when braking the vehicle. As shown in FIG. 7, the fin sliding surface 22n is a surface that is approximately parallel to the fin sliding surface 22e of the fin 22c formed on the second surface 22b of the disk portion 22. The width of the fin sliding surface 22n and the central angle _θ2 formed by both ends of the arc of each fin sliding surface 22n and the center of rotation O of the disk portion 22 can be appropriately changed depending on the number of fins 22m formed, etc.

(Fin groove 22o)
The fin groove 22o is formed between a plurality of adjacent fins 22m. The fin groove 22o is formed by the side surfaces of the adjacent fins 22m and the surface connecting the lowest ends of the side surfaces. As shown in FIG. 10 and the like, the cross section of the fin groove 22o perpendicular to the longitudinal direction has a substantially V-shape, but is not limited to this and may be U-shaped or the like. The number of fin grooves 22o formed on the second surface 22b is not particularly limited and can be appropriately set according to the number of fins 22m formed, etc. In the figure, the fin grooves 22d are formed at equal intervals, but may be unequal. Furthermore, in the figure, the width of the fin groove 22d is equal from the rotation center O of the disk portion 22 to the outer edge, but is not limited to this. There is no particular limit to the depth of the fin groove 22o (the height of the fin 22m) and it can be appropriately set. The fin groove 22o and the fin groove 22d may have the same shape or different shapes.

In this embodiment, the fin grooves 22o are out of phase with the fin grooves 22d formed on the opposite surface 22a (first surface). That is, as shown in FIG 7, a fin 22c is disposed on the opposite side (first surface side) of any fin groove 22o.
In this embodiment, it is not necessary for all of the fin grooves 22o to be out of phase with the fin grooves 22d on the first surface, but it is sufficient that at least one fin groove 22o is out of phase with the fin groove 22d.

In this embodiment, the effects of making the phases of the fins and fin grooves on both sides of the disk portion 22 different from each other are as follows. That is, by making the phases different from each other, it is possible to deepen the depth of the fin grooves on both sides while making the overall thickness of the disk portion 22 uniform. By making the overall thickness of the disk portion 22 uniform, it is possible to avoid distortion and cracks in the rotor due to thermal effects, and by making the fin grooves deeper, it is possible to improve cooling performance.

(Second embodiment: air flow during rotor rotation)
The flow of cooling air when the brake disc rotor 200 of this embodiment rotates will be described below.

As the vehicle travels, the brake disc rotor 200 rotates in the direction of travel. The air around the brake disc rotor 200 is discharged from the vicinity of the rotation center O of the disc portion 22 through the fin grooves 22d and fin grooves 22o toward the outer edge due to the centrifugal force of the rotation. That is, this air passes through the fin grooves 22d and fin grooves 22o while removing heat held by the brake disc rotor 200 from both sides of the disc portion 22, and is discharged outside the vehicle from the outer edge. Therefore, the brake disc rotor 200 of this embodiment can further improve the cooling performance of the rotor. In this embodiment, the cooling air flows from the center of the vehicle into the fin groove 22o as shown by the arrow in FIG. 9, and is discharged toward the outer edge. As shown in FIG. 9, a through hole for passing the cooling air is formed on the rotation center O side of the fin groove 22o (i.e., near the connection between the hat portion 21 and the fin 22c). However, in this embodiment, the through hole is not an essential configuration. In other words, as long as fins are formed on both sides of the disk portion 22, the brake disk rotor 200 of this embodiment can further improve cooling performance.

In the cross-sectional view of FIG. 9, the fins 22c and fin grooves 22o each have a uniform thickness from the center of rotation O to the outer edge. However, this is not limited to this, and the thickness may be different from the center of rotation O to the outer edge. That is, as shown in FIG. 10, by making the depth of the fin grooves 22o at the rotor outer edge deeper than the depth of the fin grooves 22o near the center of rotation O to generate negative pressure, the cooling air can more easily flow into the fin grooves 22o, improving cooling performance.

The brake disc rotor 200 of this embodiment may be used in combination with a known dust cover DC. Specifically, as shown in Figs. 8 to 10, the dust cover _DC1 and the dust cover DC2 can be arranged on both the first surface 22a and the second surface 22b of the brake disc rotor ₂₀₀ of this embodiment with a gap therebetween. As shown in Fig. 10, on the surface 22a (first surface) on the inside of the vehicle, the space surrounded by the fin groove 22d and the dust cover _DC1 becomes the flow path of the cooling air. On the other hand, on the surface 22b (second surface) on the outside of the vehicle, the space surrounded by the inside of the fin groove 22o and the dust cover _DC2 becomes the flow path of the cooling air.

(Effects of the Second Embodiment)
The effects of using the brake disc rotor 200 of this embodiment alone are as follows. That is, in this embodiment, a cooling air flow path is formed between the brake disc rotor 200 and the dust cover _DC1 and the dust cover _DC2 , so that a solid disc without a hollow structure can be used to obtain the same cooling effect as a conventional ventilated type disc. In addition, the air around the brake disc rotor 200 passes through the fin grooves 22d and 22o while removing the heat held by the brake disc rotor 200 from both sides of the disc portion 22, and is released to the outside of the vehicle from the outer edge portion. Therefore, the brake disc rotor 200 of this embodiment can further improve the cooling performance of the rotor. In addition, as the same effects as the first embodiment, there are also effects such as being able to be manufactured at a lower cost than a ventilated type disc, and being able to clean the pad surface after the fade phenomenon.

Furthermore, when the brake disc rotor 200 of this embodiment is used in combination with two dust covers _DC1 and _DC2 , the effect is as follows. That is, the cooling air flowing through the fin groove 22d indirectly transfers the heat taken from the brake disc rotor 200 to the dust cover _DC1 . Similarly, the cooling air flowing through the fin groove 22o indirectly transfers the heat taken from the brake disc rotor 200 to the dust cover _DC2 . In this way, the heat held inside the brake disc rotor 200 of this embodiment is transferred to the cooling air flowing on both sides and released in the direction of the rotor outer edge, and is also transferred to the two dust covers. Therefore, the cooling performance of the rotor can be further improved.

The above describes preferred embodiments of the present disclosure with reference to the attached drawings, but the present disclosure is not limited to these examples. In other words, it is understood that a person skilled in the art would clearly be able to attempt further modifications to the above-described embodiments.

100: brake disc rotor, 200: brake disc rotor, 21: hat portion, 22: disc portion, 22a: vehicle inner surface (first surface), 22b: vehicle outer surface (second surface), O: rotation center, 22c: fin, 22e: fin sliding surface, 22d: fin groove, 22m: fin, 22n: fin sliding surface, 22o: fin groove, DC: dust cover, _DC1 : dust cover, _DC2 : dust cover

Claims (5)

a disk portion having a first surface and a second surface;
a plurality of radial fins formed on at least one of the first surface and the second surface from a rotation center of the disk portion toward an outer edge thereof;
A top portion that serves as a sliding surface formed on the fin;
A brake disc rotor having The brake disc rotor according to claim 1, wherein the fins are formed on both the first surface and the second surface. The brake disc rotor according to claim 2, wherein the fins formed on the first surface and the fins formed on the second surface are out of phase with each other. A dust cover is disposed opposite the fin,
The brake disc rotor according to claim 3 , wherein a cooling air flow path is formed between the fin and the dust cover. A vehicle comprising the brake disc rotor according to any one of claims 1 to 4.

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