JP7820137B2 - disc brake pads - Google Patents

Description

The present invention relates to a disc brake pad.

In recent years, with the trend toward making automobiles more environmentally friendly and fuel-efficient, efforts to reduce the weight of each automobile part have been considered and implemented. Typically, metal materials account for more than half of the raw materials used in an automobile, but their use has been declining year by year in order to reduce the weight of the vehicle body. Furthermore, in recent years, there has been an increasing trend toward the use of aluminum (aluminum alloys or aluminum composites) or resins as materials for reducing the weight of the vehicle body. Amid this trend toward weight reduction, there is a growing demand for weight reduction not only in the body and frame, but also in each of the elements that make up the vehicle.

Similarly, the demand for lighter vehicle bodies is also growing for disc brake pads, which are one of the components of the braking system used to brake a vehicle. Traditionally, disc brake pads have used back plates made of steel plate material, but in recent years, back plates made primarily of lightweight metals such as aluminum and magnesium, their alloys, and resins have been proposed (see, for example, Patent Documents 1 to 3).

Japanese Patent Application Laid-Open No. 2000-46078 JP 2013-60974 A Japanese Patent Application Laid-Open No. 2015-135177

However, lightweight materials such as aluminum, magnesium, and other metals, their alloys, and resins tend to be less durable than steel, and steel is more difficult to reduce in weight than lightweight materials such as aluminum, magnesium, and other metals, their alloys, and resins. Therefore, there has been a demand for disc brake pads equipped with back plates that achieve both further weight reduction and durability.

The present invention was made in consideration of the existence of the above-mentioned problems, and aims to provide a disc brake pad equipped with a back plate that is lightweight and has improved durability.

The present inventors have found that the above problems can be solved by adopting the following configurations. That is, the present invention relates to the following [1] to [9].
[1] A disc brake pad comprising a friction material that comes into frictional contact with a disc rotor that rotates together with a vehicle wheel during a brake operation, and a back plate that is fixed to the friction material, wherein the back plate comprises a back plate main body, a pair of ears that are arranged on both sides of the back plate main body, and a thickened portion that is thickened on the side opposite to the surface to which the friction material is fixed, and the thickened portion comprises a pair of first thickened portions that are thickened at the pair of ears, and a pair of second thickened portions that are adjacent to the first thickened portions and that are thickened at both sides of the back plate main body. a pair of second thick portions, the second thick portions comprising an inner second thick portion arranged on the inner side of the disc rotor of the back plate main body portion, and an outer second thick portion adjacent to the inner second thick portion and arranged on the outer side of the disc rotor of the back plate main body portion, wherein, in rear view, the maximum distance from the side of the ear opposite the back plate main body portion to the inner second thick portions is greater than the maximum distance on the disc rotor from the side of the ear opposite the back plate main body portion to the outer second thick portions.
[2] The disc brake pad according to [1] above, wherein the ear portion comprises a pair of root portions having a curved shape adjacent to and connected to the back plate main body portion, the inner second thick portion comprises inner second thick portion side portions arranged along the side portions of the back plate main body portion, the inner second thick portion side portions extending to the inner end portions of the inner root portion, and the outer second thick portion extending to the outer end portions of the outer root portion.
[3] The disc brake pad according to [2] above, wherein the inner circumferential second thick portion includes a diagonal portion disposed at an angle relative to the radial direction of the disc rotor from a side portion of the inner circumferential second thick portion.
[4] The disc brake pad according to the above [3], wherein the side portion of the inner circumferential second thick portion and the diagonal portion are integral with each other.
[5] The disc brake pad according to the above [3] or [4], wherein the diagonal cross section does not have a curved shape.
[6] The disc brake pad according to the above [3] or [4], wherein the diagonal cross section has at least a part of a curved shape.
[7] The disc brake pad according to any one of [1] to [6] above, wherein the thickness of the back plate body and the ear portions in the plate thickness direction is 15 mm or less, and the thickness of the thick portion in the plate thickness direction is 0.1 mm or more.
[8] The disc brake pad according to any one of the above [1] to [7], wherein the material of the back plate is at least one selected from the group consisting of an iron alloy, an aluminum alloy, an aluminum composite material, and a magnesium alloy.
[9] The disc brake pad according to the above [8], wherein the material of the back plate is an aluminum alloy or an aluminum composite material, the Cu content of the aluminum alloy or the aluminum composite material is 1% or less, and the Mg content is 3% or less, and the aluminum alloy or the aluminum composite material does not belong to a high-strength aluminum alloy.

The present invention provides a disc brake pad equipped with a back plate that is lightweight and has improved durability.

1 is a front view illustrating the appearance of a disc brake pad according to an embodiment of the present invention, showing the surface that faces the wheel when attached. FIG. 2 is an external rear view illustrating the back plate according to the embodiment. FIG. 2 is a schematic bottom view illustrating the appearance of a backplate according to the embodiment. 1 is an external rear view illustrating a state in which the disc brake pad according to the present embodiment is attached to a torque receiving member. FIG. FIG. 10 is an external rear view illustrating a back plate according to a modified example. FIG. 10 is an external rear view illustrating a back plate according to a modified example. FIG. 10 is an external rear view illustrating a back plate according to a modified example. FIG. 10 is an external rear view illustrating a back plate according to a modified example. FIG. 10 is an external rear view illustrating a back plate according to a modified example.

Preferred embodiments for carrying out the present invention will be described below with reference to the drawings. Note that the following embodiments do not limit the inventions according to the claims, and not all of the combinations of features described in the embodiments are essential to the solution of the invention.
The same applies to numerical values and their ranges, and do not limit the present invention. In the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in the Examples. In addition, embodiments in which the items described in this specification are combined in any manner are also included in the present invention.
In this specification, unless otherwise specified, the term "approximately" refers to a concept including differences or modifications to the extent that identity is not lost. In this specification, the term "anti-X portion" refers to a portion located on the opposite side of the X portion.

The disc brake pad 100 according to this embodiment will be described using Figures 1 to 4. Figure 1 is an external front view illustrating the disc brake pad according to this embodiment, showing the surface that faces the wheel when installed. Figure 2 is an external rear view illustrating the back plate according to this embodiment, and Figure 3 is an external schematic bottom view illustrating the back plate according to this embodiment. Figure 4 is an external rear view illustrating the state in which the disc brake pad according to this embodiment is installed on a torque receiving member.

[Disc brake pad 100]
As shown in FIGS. 1 to 4, a disc brake pad 100 according to this embodiment is a disc brake pad comprising a friction material 10 that comes into frictional contact with a disc rotor 20 that rotates together with a vehicle wheel during a braking operation, and a back plate 30 to which the friction material 10 is fixed. The back plate 30 comprises a back plate main body 31, a pair of ears 33, 33 disposed on both sides of the back plate main body 31, and a thick portion 40 that is thickened on the side opposite to the surface to which the friction material 10 is fixed. The thick portion 40 comprises a pair of first thick portions 41, 41 that are thickened from the pair of ears 33, 33, and a back plate 30 that is adjacent to the first thick portion 41 and that is thickened by a back plate 30. The backplate main body 31 is provided with a pair of second thick portions 43, 43 formed by thickening both side portions of the backplate main body 31, and the second thick portion 43 includes an inner second thick portion 45 arranged on the inner side of the disc rotor of the backplate main body 31, and an outer second thick portion 47 adjacent to the inner second thick portion 45 and arranged on the outer side of the disc rotor of the backplate main body 31, and the maximum distance D2 in the circumferential direction of the disc rotor from the anti-backplate main body side 37 of the ear 33 to the inner second thick portion 45 is greater than the maximum distance D1 in the circumferential direction of the disc rotor from the anti-backplate main body side 37 of the ear 33 to the outer second thick portion 47.

The disc brake pad 100 can be surface-coated to improve corrosion resistance and stabilize appearance quality. Surface coating techniques that can be used include, for example, powder coating using electrostatic spraying, and solvent coating using a spray.

<Friction material 10>
1, 2, and 4, during braking, the friction material 10 is pressed by a pressing member (not shown) that presses the disc brake pad 100, and comes into frictional contact with the disc rotor 20 that rotates together with the vehicle wheel, and the generated frictional force brakes the rotation of the wheel that is coupled to the disc rotor 20 and rotates integrally with it. The friction material 10 only needs to be fixed to a portion of the back plate 30 described below excluding ear portions 33, and the shape of the friction material 10 may be substantially the same as or different from a back plate main body portion 31 of the back plate 30 described below. The method for fixing the friction material 10 to the back plate 30 is not particularly limited, and they can be fixed together using a known adhesive, for example.

The friction material 10 is not particularly limited, and known friction materials can be used. For example, a preferred embodiment is a friction material formed from a friction material composition containing a binder, organic filler, inorganic filler, and a fibrous base material. The friction material 10 can be formed, for example, by overlapping the friction material composition or a preform of the friction material composition with the back plate 30, thermocompressing the resulting material, and then heat-treating the material to harden the thermosetting resin binder. The friction material 10 may also be formed by combining two types of friction material compositions: an upper layer and an underlayer. In this case, the disc brake pad 100 can have a configuration in which the upper layer is disposed on the back plate 30 via the underlayer, with the underlayer positioned on the friction sliding surface. The friction material 10 serves as the upper layer, and the underlayer functions primarily as a layer with excellent shear strength and crack resistance. Known underlayers can be used.

The thickness of the friction material 10 is not particularly limited, but from the standpoint of durability, it can be 4 mm or more and 15 mm or less, 6 mm or more and 15 mm or less, or 7 mm or more and 13 mm or less.

<Back plate 30>
As shown in Figures 1 to 4, the backplate 30 of this embodiment includes a backplate main body portion 31, a pair of ear portions 33, 33 arranged on both sides of the backplate main body portion 31, and a thick portion 40.

The backplate 30 according to this embodiment can be formed integrally with the backplate main body 31 and the pair of ears 33, 33. By integrally molding the backplate main body 31 and the pair of ears 33, 33, durability tends to be improved. The backplate main body 31 and the pair of ears 33, 33 may be made of the same material, or may be made of different materials.

The thickness of the backplate main body 31 and the ears 33 in the thickness direction can be changed as appropriate depending on the specific gravity of the material used for the backplate, and is not particularly limited. However, both can be set to 2 mm to 15 mm, 3 mm to 11 mm, or 4 mm to 10 mm. The backplate 30 according to this embodiment includes a thick portion 40 that is thicker in the thickness direction than the backplate main body 31 and the ears 33. This allows for a thinner backplate main body 31, particularly, for weight reduction while improving durability. The thickness of the backplate main body 31 and the ears 33 in the thickness direction may be approximately the same or different. Having the thickness of the backplate main body 31 and the ears 33 in the thickness direction approximately the same tends to improve manufacturing efficiency.

The thickness of the backplate main body 31 in the thickness direction is measured at three points: the center, lower right, and upper left of the backplate main body 31, as viewed from the pressing surface (on the paper surface of Figures 2 and 4) that is pressed by a pressing member (not shown) that presses against the disc brake pad 100 during braking, so as not to overlap the area where the thickened portion 40 is formed, and the average of these measurements can be used as the thickness of the backplate main body 31 in the thickness direction. In this case, if the backplate main body 31 has been subjected to additional processing such as engraving, drilling, slitting, or similar processing, it is preferable to measure at a position that does not overlap the area where the thickened portion 40 is formed and is at least 2 mm away from the additional processing.

As shown in FIG. 1, the backplate main body 31 according to this embodiment has a generally rectangular shape with chamfered edges, but the shape of the backplate main body 31 is not limited to this and may also have a generally rectangular shape without chamfered edges. Furthermore, the backplate main body 31 may be provided with, for example, friction material fall-off prevention holes to prevent the friction material 10 from falling off, or may have weight-reducing holes or be engraved in areas that are less likely to receive torque from the disc rotor 20.

As shown in Figures 1, 2, and 4, the pair of ears 33, 33 are ear-shaped portions that protrude from both sides of the backplate main body 31 in the disc rotor circumferential direction. As shown in Figure 4, the pair of ears 33, 33 are held by a torque receiving member 70 that receives torque from the disc rotor 20, which acts as a reaction force to the frictional force generated when the disc brake pad 100 is pressed by a pressing member (not shown) during braking. In this embodiment, the pair of ears 33, 33 are positioned approximately in the center of both sides of the backplate main body 31 in the disc rotor radial direction, but the position of the ears 33 is not particularly limited. Note that "approximately in the center of both sides of the backplate main body 31 in the disc rotor radial direction" refers to a position between one-third and two-thirds of the length of both sides of the backplate main body 31 in the disc rotor radial direction. When the ear holders 71 of the torque receiving member 70 that hold the ears 33 have a shape that corresponds to the ears 33, installation of the disc brake pad 100 on the torque receiving member 70 tends to be easier.

1, 2, and 4, the ear portion 33 may include a root portion 35 that is adjacent to the backplate main body portion 31 and connects to the backplate main body portion 31 in a curved shape. More specifically, the root portion 35 (35A, 35B) having a curved shape may be configured so that the root end, where the curved shape ends on the backplate main body portion 31 side, connects to the end of the backplate main body portion 31. Connecting the ear portion 33 to the backplate main body portion 31 via the root portion 35 (35A, 35B) having a curved shape can further improve the durability of the connection portion between the backplate main body portion 31 and the ear portion 33. The root portion 35 in this embodiment consists of a root portion 35A on the outer periphery of the disc rotor (hereinafter simply referred to as the outer periphery root portion 35A) and a root portion 35B on the inner periphery of the disc rotor (hereinafter simply referred to as the inner periphery root portion 35B). However, the configuration may include only the outer periphery root portion 35A of the disc rotor, only the inner periphery root portion 35B of the disc rotor, or no root portion 35B at all.

As shown in Figures 2 and 4, the thickened portion 40 can be considered to be a portion of the backplate main body 31 and the pair of ears 33, 33 that are thickened on the side opposite to the surface to which the friction material 10 is fixed, and does not include the backplate main body 31 or the pair of ears 33, 33, as shown in Figure 3. In other words, the thickened portion 40 is a portion that is thicker in the plate thickness direction than the backplate main body 31 and the pair of ears 33, 33. The thickened portion 40 consists of a pair of first thickened portions 41, 41 that are formed by thickening the pair of ears 33, 33, and a pair of second thickened portions 43, 43 that are formed by thickening both side portions of the backplate main body 31.

The thickened portion 40 may be formed by integrally molding the backplate main body 31 and the pair of ears 33, 33, by gluing the thickened portion 40 to the backplate main body 31 and the ears 33, or by performing cutting or other processing on the portions of the backplate 30 that are not thickened.

The thickness of the thick-walled portion 40 in the plate thickness direction is not particularly limited, but can be set to 0.1 mm or more and 5.0 mm or less from the viewpoint of achieving both lightweight and durability.

The first thick portion 41 may have the same shape as the ear portion 33. Having the first thick portion 41 have the same shape as the ear portion 33 tends to make the back plate 30 easier to manufacture. However, for example, a portion of the ear portion 33 may not be thickened, and the first thick portion 41 and the ear portion 33 may have different shapes. Alternatively, the first thick portion 41 may have a thin portion that is thicker in the thickness direction than the ear portion 33 but thinner in the thickness direction than the first thick portion 41. In the present invention, the thickened portion of the ear portion 33 that is thicker in the thickness direction than the ear portion 33 is the first thick portion 41, and this thin portion is included in the first thick portion 41.

As shown in Figures 2 and 4, the second thick portions 43 are thickened portions of both sides of the backplate main body 31 in the disc rotor circumferential direction. In other words, the second thick portions 43 are portions of both sides of the backplate main body 31 that are thicker in the plate thickness direction than the backplate main body 31. The second thick portions 43 include an inner second thick portion 45 located on the disc rotor inner side of the backplate main body 31, and an outer second thick portion 47 adjacent to the inner second thick portion 45 and located on the disc rotor outer side of the backplate main body 31. The second thick portions 43 are configured so that the maximum distance D2 in the disc rotor circumferential direction from the anti-backplate main body side 37 of the ear 33 to the inner second thick portion 45 is greater than the maximum distance D1 in the disc rotor circumferential direction from the anti-backplate main body side 37 of the ear 33 to the outer second thick portion 47.

The inner second thick portion 45 is a thickened portion located on the circumferential side of the backplate main body 31, facing the inner periphery of the disc rotor. In this embodiment, the inner second thick portion 45 has a generally trapezoidal shape. However, the shape of the inner second thick portion 45 is not limited to this. For example, as shown in FIG. 5, a non-thick portion 39, which is a non-thickened portion of the backplate main body 31, may be provided on the side of the backplate main body 31 facing the inner periphery of the disc rotor to reduce weight in areas less susceptible to torque from the disc rotor 20. Furthermore, for weight reduction, a thin portion may be provided that is thinner in the thickness direction than the inner second thick portion 45 but thicker in the thickness direction than the backplate main body 31. There are no particular limitations on the shape of the non-thick portion 39 and the thin portion of the backplate main body 31 that are not thickened. As described above, the thin portion is included in the inner second thick portion 45. Furthermore, as shown in FIG. 5, even in this embodiment where the back plate 30 has a non-thick portion 39 on the side in the circumferential direction of the disc rotor, that is, on the inner side of the disc rotor, the maximum distance D2 in the circumferential direction of the disc rotor from the side 37 of the ear 33 opposite the back plate main body to the inner second thick portion 45 remains the same as when the non-thick portion 39 is not present.

The outer-periphery-side second thick portion 47 is adjacent to the inner-periphery-side second thick portion 45 and is located on the outer peripheral side of the disc rotor of the backplate main body 31, where the backplate main body 31 is thickened. The outer-periphery-side second thick portion 47 can be configured to extend from the inner-periphery-side second thick portion 45 along the side edge of the backplate main body 31 to the outer peripheral end of the disc rotor at the connection between the ear 33's root portion 35A on the outer peripheral side of the disc rotor and the backplate main body 31. In other words, the outer-periphery-side second thick portion 47 can be configured to extend from the inner-periphery-side second thick portion 45 to the outer peripheral end of the root portion 35A on the outer peripheral side of the disc rotor. This configuration tends to improve the durability of the connection between the backplate main body 31 and the ear 33. The outer-periphery-side second thick portion 47 may be configured to extend at least to the outer-periphery-side end of the root portion 35A on the outer periphery of the disc rotor, or may be configured to extend beyond the outer-periphery-side end of the root portion 35A on the outer periphery of the disc rotor. Although the outer-periphery-side second thick portion 47 according to this embodiment is configured to have a substantially rectangular shape, the shape of the outer-periphery-side second thick portion 47 is not limited thereto. For example, the outer-periphery-side second thick portion 47 may have a chamfered shape in which corners on the outer periphery of the disc rotor are chamfered, or may have a triangular, trapezoidal, polygonal, or other shape. Furthermore, similar to the inner-periphery-side second thick portion 45, for weight reduction, the backplate main body 31 may have a non-thick portion 39 at the end of the backplate main body 31 on the outer periphery of the disc rotor, which is a portion of the backplate main body 31 that is not thickened. Furthermore, the backplate main body 31 may have a thin portion that is thinner in the thickness direction than the outer-periphery-side second thick portion 47 but thicker in the thickness direction than the backplate main body 31. There are no particular restrictions on the shapes of the non-thick portion 39 and the thin portion of the back plate main body 31 that are not thickened. As in the case described above, the thin portion is included in the outer circumferential second thick portion 47.

As described above, the disc brake pad 100 according to this embodiment is configured so that the maximum distance D2 in the circumferential direction of the disc rotor from the side 37 of the ear 33 opposite the back plate main body to the inner second thick portion 45 is greater than the maximum distance D1 in the circumferential direction of the disc rotor from the side 37 of the ear 33 opposite the back plate main body to the outer second thick portion 47. This configuration prevents deformation of the back plate 30 due to torque from the disc rotor 20 generated during braking, improving the durability of the back plate 30.

2, the outer peripheral second thick portion 47 according to this embodiment has a generally rectangular shape, so that the maximum distance D1 from the anti-backplate main body side 37 of the ear 33, which is located on the opposite side of the backplate main body 31, to the outer peripheral second thick portion 47 in the disc rotor circumferential direction is generally the same at any position on the outer peripheral second thick portion 47. Meanwhile, the inner peripheral second thick portion 45 according to this embodiment has a generally trapezoidal shape, so that the maximum distance D2 from the anti-backplate main body side 37 of the ear 33 to the inner peripheral second thick portion 45 in the disc rotor circumferential direction is the distance from the anti-backplate main body side 37 of the ear 33 to the base of the trapezoid shape of the inner peripheral second thick portion 45. For ease of explanation, in Figure 2, an extension line is drawn along the side 37 of the ear 33 opposite the back plate main body, and an extension line is also drawn from the base of the trapezoidal shape of the inner second thick portion 45, showing the maximum distance D2 from the side 37 of the ear 33 opposite the back plate main body to the inner second thick portion 45 in the circumferential direction of the disc rotor.

Furthermore, as shown in FIG. 2, the inner second thick portion 45 and the outer second thick portion 47 can be arranged so that an extension line EL of the connection point where the inner second thick portion 45 and the outer second thick portion 47 connect passes through approximately the center of the ear portion 33 in the radial direction of the disc rotor. Here, "approximately the center of the ear portion 33 in the radial direction of the disc rotor" refers to a position 1/3 to 2/3 of the way along the length of the ear portion 33 in the radial direction of the disc rotor. This configuration makes it easy to achieve both durability and lightweight design.

From the standpoint of durability, the extension line of the connection point where the inner second thick portion 45 and the outer second thick portion 47 join can be positioned so that it passes through 1/3 to 2/3 of the length of the ear 33 in the radial direction of the disc rotor, or 2/5 to 4/5 of the length of the ear 33 in the radial direction of the disc rotor, based on the inner end of the ear 33 on the disc rotor.

The material of the backplate 30 (referring to the material of the backplate main body 31, the lug portions 33, and the thick portions 40, respectively; the same applies below) is not particularly limited, but can be an iron alloy, an aluminum alloy, a magnesium alloy, a resin, or a composite material consisting of at least two of these. Furthermore, the backplate 30 can be subjected to a surface treatment, for example, to improve the adhesion of the surface coating and corrosion resistance when a surface coating is applied. Suitable surface treatments include, for example, zirconium treatment, chromate treatment, zinc phosphate treatment, boehmite treatment, anodizing treatment, silane coupling treatment, electrolytic nickel plating treatment, electroless nickel plating treatment, and Geomet treatment.

The back plate 30 can be made of, for example, an aluminum alloy with a Cu content of 1% or less, or an aluminum composite material using such an aluminum alloy. By keeping the Cu content in the aluminum alloy at 1% or less, corrosion resistance tends to be improved.

The back plate 30 can be made of, for example, an aluminum alloy that does not fall under the category of high-strength aluminum alloys, or an aluminum composite material using such an aluminum alloy, that contains 1% or less of Cu and 3% or less of Mg. Using such a material tends to help prevent stress corrosion cracking. Here, stress corrosion cracking refers to cracks that form along grain boundaries due to stress generated at the tip of intergranular corrosion that occurs at the grain boundaries. By keeping the Mg content in the aluminum alloy at 3% or less, precipitation of Al-Mg alloys within grain boundaries can be effectively suppressed, making intergranular corrosion less likely to occur. Furthermore, the lower the strength, the less likely cracks due to crack propagation tend to occur. Therefore, the above-mentioned alloys, which have resistance to stress corrosion cracking, are suitable for use as the material for the back plate 30.

When using an aluminum alloy or an expanded aluminum composite material as the material for the back plate 30, there are no particular limitations. However, from the standpoint of strength against the torque from the disc rotor 20 and the pressing force of the pressing member, aluminum alloys such as 2000 series (Al-Cu series), 4000 series (Al-Si series), 5000 series (Al-Mg series), 6000 series (Al-Mg-Si series), and 7000 series (Al-Zn-Mn series) are suitable.

When using an aluminum alloy or wrought aluminum composite material as the material for the back plate 30, there are no particular limitations, but it is preferable that the material exhibits little deterioration in material strength and yield strength even in high-temperature environments of 100°C and 250°C. This is because it is desirable that the material strength does not decrease as the temperature of the back plate 30 increases during braking. An example of an aluminum alloy that exhibits little deterioration in material strength in high-temperature environments is A5454.

The aluminum composite material is manufactured by dispersing ceramic particles in the aluminum alloy or by impregnating a porous ceramic body with the aluminum alloy, and therefore has a higher Young's modulus than the aluminum alloy, thereby achieving higher rigidity when used as the material for the back plate 30. Examples of the ceramic that can be used include oxide ceramics such as _Al2O3 , _TiO2 , _SiO2 , and _ZrO2 , carbide ceramics such as SiC and _TiC , and nitride ceramics such as TiN.

The above describes the disc brake pad 100 according to this embodiment, but the technical scope of the present invention is not limited to the scope described in the above embodiment. Various modifications and improvements can be made to the above embodiment. In the following description, components that are the same as or similar to those in the above embodiment may be assigned the same reference numerals and their description may be omitted.

For example, in the above-described embodiment, the thickened portion 40 is provided on the side opposite to the surface to which the friction material 10 is fixed, but the thickened portion may also be provided on the surface to which the friction material 10 is fixed.

In the above-described embodiment, the friction material 10 and the back plate 30 are directly bonded to each other. However, for example, the friction material 10 and the back plate 30 may be bonded to each other via an underlayer. A preferred embodiment of the underlayer is a friction material formed from a friction material composition containing a binder, an organic filler, an inorganic filler, and a fibrous base material. When the friction material 10 is bonded to the back plate 30 via the underlayer, the friction material composition and the underlayer composition, or a preform of the friction material composition and the underlayer composition, are superimposed on the back plate 30 and subjected to thermocompression molding, followed by heat treatment to cure the thermosetting resin binder. When an underlayer is provided between the friction material 10 and the back plate 30, the thickness of the underlayer can be set to 1 mm to 5 mm, 1 mm to 3 mm, or 1 mm to 2 mm, from the viewpoints of improving the insulating effect between the friction material 10 and the back plate 30 and effectively suppressing cracks and breakage in the back plate 30.

Furthermore, in the above-described embodiment, the inner second thick portion 45 has a generally trapezoidal shape, and the outer second thick portion 47 has a generally rectangular shape. However, for example, as shown in FIG. 6, the shape of the inner second thick portion 45 (45A, 45B) of the thick portion 40 (40A, 40B) of the back plate 30 (30A, 30B) can be changed. As shown in the sub-views (a) and (b) of FIG. 6, the inner second thick portion 45 (45A, 45B) may have an arc or curved shape that widens toward the inner periphery of the disc rotor, i.e., it may have an arc or curved shape that narrows toward the outer periphery of the disc rotor. Furthermore, when the inner second thick-walled portion 45 (45A, 45B) has an arc shape, the center of the arc may be configured to be on the outside of the back plate 30A, as shown in the partial view (a) of Figure 6, or on the inside of the back plate 30B, as shown in the partial view (b) of Figure 6.

Furthermore, for example, as shown in FIG. 7, the shape of the inner second thick portion 45 (45C, 45D) of the thick portion 40 (40C, 40D) of the back plate 30 (30C, 30D) can be changed. For example, as shown in the sub-diagram (a) of FIG. 7, the inner second thick portion 45C may have a substantially circular or substantially elliptical shape, and as shown in the sub-diagram (b) of FIG. 7, the inner second thick portion 45D may have a substantially rectangular shape or a polygonal shape with pentagons or more sides.

Furthermore, for example, as shown in the partial view (a) of FIG. 8, the outer peripheral second thick portion 47A of the back plate 30E may be configured to widen toward the outer peripheral side of the disc rotor, i.e., narrow toward the inner peripheral side of the disc rotor. Also, for example, as shown in the partial view (b) of FIG. 8, the outer peripheral second thick portion 47B of the back plate 30F may be configured to widen toward the inner peripheral side of the disc rotor. Furthermore, the outer peripheral second thick portion 47B, which is configured to widen toward the inner peripheral side of the disc rotor, and the inner peripheral second thick portion 45' may be connected in a linear shape without providing a constriction.

9, the inner second thick portion 45G may include an inner second thick portion side 49 arranged along the side of the backplate main body, and a diagonal brace 51 inclined from the inner second thick portion side 49 to the radial direction of the disc rotor, and the inner second thick portion side 49 may extend to the inner edge of the inner root portion 35B of the disc rotor. By having the inner second thick portion side 49 extend to the edge of the inner root portion 35B of the disc rotor, it is possible to achieve both improved durability and weight reduction at the connection between the backplate main body 31 and the ear portion 33. It is sufficient that the inner second thick portion side 49 extends at least to the inner edge of the inner root portion 35B of the disc rotor, and it may also extend beyond the inner edge of the inner root portion 35B.

In the above-described embodiment, the inner circumferential second thick portion side portion 49 and the diagonal joint portion 51 are integrally configured. However, as shown in FIG. 9 , the inner circumferential second thick portion side portion 49 and the diagonal joint portion 51 can be provided separately, thereby further reducing the weight of the back plate 30G while maintaining its durability. In the back plate 30G according to this modified example, the diagonal joint portion 51 is formed to have a substantially rectangular shape and is not curved, but at least a portion of the diagonal joint portion 51 may have a curved shape. That is, the diagonal joint portion 51 may be configured to be bent, for example, in a hook shape. Alternatively, the inner circumferential second thick portion side portion 49 and the diagonal joint portion 51 may be configured to have a substantially U-shape.

When the inner second thick portion 45 has a diagonal cross section 51, the maximum distance D2 in the circumferential direction of the disc rotor from the side 37 of the ear 33 opposite the backplate main body to the inner second thick portion 47 is the distance from the side 37 of the ear 33 opposite the backplate main body to the end of the diagonal cross section 51 on the center side of the backplate main body 31, as shown in Figure 9.

It is clear from the claims that such modifications and improvements are also included within the technical scope of the present invention.

100: disc brake pads,
10: Friction material,
20: disc rotor,
30 (30A, 30B, 30C, 30D, 30E, 30F): back plate, 31: back plate main body portion, 33: ear portion, 35 (35A, 35B): root portion, 37: side portion opposite to back plate main body portion, 39: non-thick portion, 40 (40A, 40B, 40C, 40D, 40E, 40F, 40G): thick portion, 41: first thick portion, 43 (43A, 43B, 43C, 43D, 43E, 43F, 43G): second thick portion, 45 (45A, 45B, 45C, 45D, 45', 45G): inner circumferential side second thick portion, 47 (47A, 47B): outer circumferential side second thick portion, 49: inner circumferential side second thick portion side, 51: diagonal cross portion,
70: Torque receiving member, 71: Ear holding part,
D1: distance, D2: distance, EL: extension line of the connection point between the inner second thick portion and the outer second thick portion

Claims (9)

a friction material that comes into frictional contact with a disc rotor that rotates together with the vehicle wheel during braking;
a back plate fixed to the friction material;
A disc brake pad comprising:
The back plate is
a backplate main body;
a pair of ears disposed on both sides of the back plate body;
a thickened portion on the opposite side to the surface to which the friction material is fixed,
The thick portion is
a pair of first thick portions formed by thickening the pair of ear portions;
a pair of second thick portions adjacent to the first thick portions and thickening both side portions of the back plate main body portion,
The second thick portion is
an inner circumferential second thick portion disposed on the inner circumferential side of the disc rotor of the back plate main body;
an outer circumferential side second thick portion adjacent to the inner circumferential side second thick portion and thickening both side portions of the back plate main body;
Equipped with
The ear portion includes a pair of root portions having a curved shape adjacent to and connected to the back plate main body portion,
A disc brake pad in which, when viewed from behind, the maximum distance in the circumferential direction of the disc rotor from the side of the ear portion opposite the back plate main body portion to the inner second thick portion is greater than the maximum distance in the circumferential direction of the disc rotor from the side of the ear portion opposite the back plate main body portion to the outer second thick portion. The ear portion includes a pair of root portions having a curved shape adjacent to and connected to the back plate main body portion,
the inner circumferential second thick portion includes an inner circumferential second thick portion side portion that is arranged along a side portion of the back plate main body portion,
2. The disc brake pad according to claim 1, wherein the inner second thick portion side extends to an inner end of the inner root portion, and the outer second thick portion extends to an outer end of the outer root portion. The disc brake pad of claim 2, wherein the inner second thick portion has a diagonal cross section that is inclined from the side of the inner second thick portion relative to the radial direction of the disc rotor. The disc brake pad of claim 3, wherein the inner circumferential second thick portion side portion and the diagonal brace portion are integral with each other. The disc brake pad according to claim 3 or 4, wherein the diagonal cross section does not have a curved shape. The disc brake pad according to claim 3 or 4, wherein at least a portion of the bracing portion has a curved shape. A disc brake pad according to any one of claims 1 to 6, wherein the thickness of the back plate main body and the ear portions is 15 mm or less, and the thickness of the thick portion is 0.1 mm or more. The disc brake pad according to any one of claims 1 to 7, wherein the back plate is made of at least one material selected from the group consisting of iron alloy, aluminum alloy, aluminum composite material, and magnesium alloy. The disc brake pad of claim 8, wherein the back plate is made of an aluminum alloy or aluminum composite material, the Cu content of the aluminum alloy or aluminum composite material being 1% or less and the Mg content being 3% or less, and the aluminum alloy or aluminum composite material not belonging to the high-strength aluminum alloy category.