disc brake pads

Abstract

To provide a disc brake pad 100 equipped with a back plate 30 reduced in weight and improved in durability.SOLUTION: A disc brake pad 100 is equipped with a friction material 10 and a back plate 30. The back plate 30 is equipped with a back plate body portion 31, a pair of ear portions 33 and 33, and a wall thickness portion 40 formed thick. The wall thickness portion 40 is composed of a pair of first wall-thickness portions 41 obtained by making the pair of ear portions 33 and 33 thick, and a pair of second wall-thickness portions 43 making both side parts of the back plate body portion 31 thick. The second wall-thickness portion 43 is equipped with an inner peripheral side second thickness portion 45 disposed on a disc rotor inner peripheral side of the back plate body portion 31, and an outer peripheral side second wall-thickness portion 47 that is adjacent to the inner peripheral side second wall-thickness portion 45 and is disposed on the disc rotor outer peripheral side of the back plate body portion 31. The inner peripheral side second wall-thickness portion 45 and the outer peripheral side second wall-thickness portion 47 satisfy a specific relationship.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a disc brake pad. [Background technology]

[0002] In recent years, with the progress of environmental friendliness and fuel efficiency in automobiles, weight reduction of each automobile part has been studied and implemented. Normally, metal materials account for more than half of the raw materials used in an automobile, but the amount of metal materials used has been decreasing year by year in order to reduce the weight of the vehicle body. In addition, in recent years, the use of aluminum (aluminum alloys or aluminum composites) or resins as materials has tended to increase in order to reduce 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 element that makes up the vehicle.

[0003] The demand for such vehicle body weight reduction is also growing for disc brake pads, which are one of the components of the brake system used for braking a vehicle. Conventionally, 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, resins, etc. have been proposed (see, for example, Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-46078 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-60974 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-135177 Summary of the Invention [Problem to be solved by the invention]

[0005] However, lightweight materials such as metals such as aluminum and magnesium, their alloys, and resins tend to be less durable than steel, and steel has the disadvantage of being more difficult to reduce in weight than lightweight materials such as metals such as aluminum and magnesium, their alloys, and resins. Therefore, there has been a demand for a disc brake pad with a back plate that achieves both further weight reduction and durability.

[0006] The present invention has been made in consideration of the existence of the above-mentioned problems, and has an object to provide a disc brake pad having a back plate that is lightweight and has improved durability. [Means for solving the problem]

[0007] The present inventors have found that the above problems can be solved by employing 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 braking, 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 disposed 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 described in [1] above, wherein the ear portion has a pair of root portions that are adjacent to and connected to the back plate main body portion and have a curved shape, the inner second thick portion has inner second thick portion side portions that are arranged along the side portions of the back plate main body portion, the inner second thick portion side portions extending to the inner end of the root portion on the inner side, and the outer second thick portion extending to the outer end of the root portion on the outer side. [3] The disc brake pad described in [2] above, wherein the inner circumferential second thick portion has a diagonal cross section arranged at an angle from the side of the inner circumferential second thick portion to the radial direction of the disc rotor. [4] The disc brake pad according to [3] above, 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 [3] or [4] above, wherein the diagonal cross section does not have a curved shape. [6] The disc brake pad according to [3] or [4] above, wherein the diagonal cross section has at least a portion having a curved shape. [7] A disc brake pad according to any one of [1] to [6] above, wherein the thickness of the back plate main body and the ear portions in the thickness direction is 15 mm or less, and the thickness of the thick portion in the 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 [8] above, 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 back plate does not belong to the high-strength aluminum alloy. [Effects of the Invention]

[0008] According to the present invention, a disc brake pad is provided that is lightweight and has a back plate that has improved durability. [Brief explanation of the drawings]

[0009] [Figure 1] 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. [Figure 2] FIG. 2 is an external rear view illustrating the back plate according to the embodiment. [Figure 3] FIG. 2 is a schematic bottom view illustrating the appearance of a backplate according to the embodiment. [Figure 4] 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. [Figure 5] FIG. 10 is an external rear view illustrating a back plate according to a modified example. [Figure 6] FIG. 10 is an external rear view illustrating a back plate according to a modified example. [Figure 7] FIG. 10 is an external rear view illustrating a back plate according to a modified example. [Figure 8] FIG. 10 is an external rear view illustrating a back plate according to a modified example. [Figure 9] FIG. 10 is an external rear view illustrating a back plate according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] 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 "opposite X portion" refers to a portion located on the opposite side of the X portion.

[0011] A disc brake pad 100 according to this embodiment will be described with reference to Figs. 1 to 4. Fig. 1 is an external front view illustrating the disc brake pad according to this embodiment, showing the surface that faces the wheel when attached. Fig. 2 is an external rear view illustrating the back plate according to this embodiment, and Fig. 3 is an external schematic bottom view illustrating the back plate according to this embodiment. Fig. 4 is an external rear view illustrating the state in which the disc brake pad according to this embodiment is attached to a torque receiving member.

[0012] [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. and a pair of second thick portions 43, 43 formed by thickening both side portions of the backplate main body 31, the second thick portion 43 comprising an inner circumferential second thick portion 45 arranged on the inner circumferential side of the disc rotor of the backplate main body 31, and an outer circumferential second thick portion 47 adjacent to the inner circumferential second thick portion 45 and arranged on the outer circumferential 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 opposite backplate main body side 37 of the ear 33 to the inner circumferential second thick portion 45 is greater than the maximum distance D1 in the circumferential direction of the disc rotor from the opposite backplate main body side 37 of the ear 33 to the outer circumferential second thick portion 47.

[0013] To improve corrosion resistance and stabilize the appearance quality, the disc brake pad 100 may be surface-coated. Examples of surface coating techniques that may be used include powder coating using electrostatic spraying and solvent coating using a spray.

[0014] <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 a 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.

[0015] 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, an organic filler, an inorganic filler, and a fibrous base material. The friction material 10 can be formed, for example, by overlapping a friction material composition or a preform of the friction material composition with a back plate 30, thermocompressing the composition, and then heat-treating the composition 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 superior in shear strength and crack resistance, and known underlayers can be used.

[0016] The thickness of the friction material 10 is not particularly limited, but from the viewpoint 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.

[0017] <Backplate 30> As shown in FIGS. 1 to 4, the backplate 30 according to this embodiment includes a backplate main body 31, a pair of ears 33, 33 arranged on both sides of the backplate main body 31, and a thick portion 40.

[0018] In the backplate 30 according to this embodiment, the backplate main body 31 and the pair of ears 33, 33 can be integrally molded. 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 different materials.

[0019] The thicknesses of the backplate main body 31 and the ear portions 33 in the plate thickness direction can be appropriately changed depending on the specific gravity of the material used for the backplate, and are not particularly limited. They can be 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 plate thickness direction than the backplate main body 31 and the ear portions 33. Therefore, the thickness of the backplate main body 31 in particular can be reduced, thereby reducing weight and improving durability. The thicknesses of the backplate main body 31 and the ear portions 33 in the plate thickness direction may be approximately the same or different. Having the thicknesses of the backplate main body 31 and the ear portions 33 in the plate thickness direction approximately the same tends to improve manufacturing efficiency.

[0020] The measurement positions for the thickness of the backplate main body 31 in the plate thickness direction are measured at three points: the center, lower right, and upper left of the backplate main body 31, as viewed from the pressing surface pressed by a pressing member (not shown) that presses the disc brake pad 100 during braking (on the paper surface of FIGS. 2 and 4), so as not to overlap the portion where the thick portion 40 is formed, and the average value of these measurements can be used as the thickness of the backplate main body 31 in the plate thickness direction. At this time, if the backplate main body 31 has been subjected to additional processing such as engraving, hole drilling, slitting, or similar processing, it is preferable to measure at a position that does not overlap the portion where the thick portion 40 is formed and that is at least 2 mm away from the additional processing.

[0021] 1, the backplate main body 31 according to this embodiment is configured to have a substantially rectangular shape with chamfered edges, but the shape of the backplate main body 31 is not limited to this and may be a substantially rectangular shape without chamfered edges. Also, 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 be provided with or engraved with weight-reducing holes in locations that are less likely to receive torque from the disc rotor 20.

[0022] As shown in FIGS. 1, 2, and 4, the pair of ears 33 are ear-shaped portions protruding from both sides of the backplate main body 31 in the disc rotor circumferential direction. As shown in FIG. 4, the pair of ears 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 a pressing member (not shown) presses the disc brake pad 100 during braking. According to this embodiment, the pair of ears 33 are disposed approximately at 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 the center of both sides of the backplate main body 31 in the disc rotor radial direction" refers to a position 1 / 3 to 2 / 3 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 corresponding to the ears 33, the disc brake pad 100 tends to be easily installed on the torque receiving member 70.

[0023] 1, 2, and 4, the ears 33 may include root portions 35 that are adjacent to and connect to the backplate main body 31 and have a curved shape. More specifically, the root portions 35 (35A, 35B) having a curved shape may be configured so that the root end, which is the portion where the curved shape ends on the backplate main body 31 side, connects to the end of the backplate main body 31. Connecting the ears 33 to the backplate main body 31 via the curved root portions 35 (35A, 35B) can further improve the durability of the connection between the backplate main body 31 and the ears 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 root portion 35A on the outer periphery) and a root portion 35B on the inner periphery of the disc rotor (hereinafter simply referred to as the root portion 35B on the inner periphery), but it may be configured to have only the root portion 35A on the outer periphery of the disc rotor, or only the root portion 35B on the inner periphery of the disc rotor, or it may not have a root portion 35 at all.

[0024] 2 and 4, the thick-walled portion 40 can be considered to be a portion where the backplate main body 31 and the pair of ears 33, 33 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 Fig. 3. In other words, the thick-walled 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 thick-walled portion 40 is made up of a pair of first thick-walled portions 41, 41 formed by thickening the pair of ears 33, 33, and a pair of second thick-walled portions 43, 43 formed by thickening both side portions of the backplate main body 31.

[0025] The thick portion 40 may be formed by integrally molding the backplate main body 31 and the pair of ear portions 33, 33, or by gluing the thick portion 40 to the backplate main body 31 and the ear portions 33, or by performing cutting processing or the like on the portions of the backplate 30 that are not thickened.

[0026] The thickness of the thick portion 40 in the plate thickness direction is not particularly limited, but from the viewpoint of achieving both weight reduction and durability, it can be set to 0.1 mm or more and 5.0 mm or less.

[0027] 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 facilitate the manufacture of the back plate 30. 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. Also, 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 the thin portion is included in the first thick portion 41.

[0028] 2 and 4, the second thick portions 43 are thickened portions of both side portions of the backplate main body 31 in the disc rotor circumferential direction. In other words, the second thick portions 43 are portions of both side portions 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 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 located on the outer side of the disc rotor of the backplate main body 31. The second thick portions 43 are configured such 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.

[0029] The inner second thick portion 45 is a thickened portion located on a side of the backplate main body 31 in the disc rotor circumferential direction, on the inner side of the disc rotor. According to the present 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 thereto. 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 on the inner side of the disc rotor to reduce weight in a location less susceptible to torque from the disc rotor 20. Furthermore, to reduce weight, 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 shapes of the non-thick portion 39 and the thin portion of the backplate main body 31 that are not thickened. As in the above-described case, the thin portion is included in the inner second thick portion 45. Furthermore, as shown in FIG. 5, in this embodiment, even if the back plate 30 has a non-thick portion 39 on the side in the circumferential direction of the disc rotor, 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 portion 33 opposite the back plate main body to the inner side second thick portion 45 is the same as when the non-thick portion 39 is not present.

[0030] The outer-periphery-side second thick portion 47 is adjacent to the inner-periphery-side second thick portion 45 and is located on the disc rotor outer periphery side 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 disc rotor outer periphery end of the connection portion where the disc rotor outer periphery-side root portion 35A of the ear portion 33 connects to the backplate main body 31. That is, 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 periphery-side end of the disc rotor outer periphery-side root portion 35A. This configuration tends to improve the durability of the connection portion between the backplate main body 31 and the ear portion 33. The outer-periphery-side second thick portion 47 can be configured to extend at least to the outer periphery-side end of the disc rotor outer periphery-side root portion 35A, or it may be configured to extend beyond the disc rotor outer periphery-side end of the disc rotor outer periphery-side root portion 35A. Although the outer-periphery-side second thick portion 47 according to this embodiment has 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. Similarly to the inner-periphery-side second thick portion 45, the backplate main body 31 may have a non-thick portion 39, which is a non-thickened portion of the backplate main body 31, at the end of the backplate main body 31 on the outer periphery of the disc rotor, to reduce weight. Furthermore, the backplate main body 31 may have a thin portion that is thinner than the outer-periphery-side second thick portion 47 but thicker than the backplate main body 31 in the thickness direction. The shapes of the non-thick portion 39 and the thin portion of the backplate main body 31 that are not thickened are not particularly limited. As described above, the thin portion is included in the outer-periphery-side second thick portion 47.

[0031] 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 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. This configuration can prevent deformation of the backplate 30 due to torque from the disc rotor 20 generated during braking, and can improve the durability of the backplate 30.

[0032] 2, the outer periphery-side second thick portion 47 according to this embodiment has a substantially 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 from the backplate main body 31, to the outer periphery-side second thick portion 47 in the disc rotor circumferential direction is substantially the same at any position on the outer periphery-side second thick portion 47. On the other hand, the inner periphery-side second thick portion 45 according to this embodiment has a substantially trapezoidal shape, so that the maximum distance D2 from the anti-backplate main body side 37 of the ear 33 to the inner periphery-side 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 periphery-side second thick portion 45. In Figure 2, for ease of explanation, an extension line is drawn along the side 37 of the ear portion 33 opposite the back plate main body portion, and an extension line is also drawn from the trapezoidal base portion of the inner second thick portion 45, showing the maximum distance D2 from the side 37 of the ear portion 33 opposite the back plate main body portion to the inner second thick portion 45 in the circumferential direction of the disc rotor.

[0033] 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 are connected passes through approximately the center of the ear 33 in the radial direction of the disc rotor. Here, "approximately the center of the ear 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 33 in the radial direction of the disc rotor. This configuration makes it easy to achieve both durability and lightweight design.

[0034] 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 connect can be arranged so as to pass through 1 / 3 to 2 / 3 of the length of the ear portion 33 in the radial direction of the disc rotor, based on the inner end of the ear portion 33 on the disc rotor, or can be arranged so as to pass through 2 / 5 to 4 / 5 of the length of the ear portion 33 in the radial direction of the disc rotor, or can be arranged so as to pass through 1 / 2 to 4 / 5 of the length of the ear portion 33 in the radial direction of the disc rotor.

[0035] The material of the backplate 30 (referring to the material of each of the backplate main body 31, the lug portions 33, and the thick portions 40, the same applies below) is not particularly limited, but may be an iron alloy, an aluminum alloy, a magnesium alloy, a resin, or a composite material made of at least two of these. Furthermore, the backplate 30 may be subjected to a surface treatment, for example, to improve the adhesion of a 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.

[0036] For example, an aluminum alloy containing 1% or less of Cu or an aluminum composite material using such an aluminum alloy can be used as the material for the back plate 30. By keeping the ratio of Cu in the aluminum alloy at 1% or less, corrosion resistance tends to be improved.

[0037] The back plate 30 can be made of, for example, an aluminum alloy containing 1% or less of Cu and 3% or less of Mg, which is not classified as a high-strength aluminum alloy, or an aluminum composite material using such an aluminum alloy. 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, which occurs at the grain boundaries. By keeping the Mg content of 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, can be suitably used as the material for the back plate 30.

[0038] When an aluminum alloy or an extruded aluminum composite material is used as the material for the back plate 30, there are no particular limitations on the material. However, from the viewpoint 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) can be suitably used.

[0039] When an aluminum alloy or an extruded aluminum composite material is used as the material for the back plate 30, 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., although there are no particular limitations. This is because it is desirable that the material strength does not decrease with the temperature rise of the back plate 30 during braking, and an example of an aluminum alloy that exhibits little deterioration in material strength in high-temperature environments is A5454.

[0040] 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.

[0041] The disc brake pad 100 according to this embodiment has been described above, 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 will be given the same reference numerals and their description may be omitted.

[0042] For example, in the above-described embodiment, the friction material 10 has a thickened portion 40 on the side opposite to the surface to which it is fixed, but the friction material 10 may also have a thickened portion on the surface to which it is fixed.

[0043] 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 an 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 harden the thermosetting resin binder. When an underlayer is provided between the friction material 10 and the back plate 30, the thickness of the underlayer may be 1 mm to 5 mm, 1 mm to 3 mm, or 1 mm to 2 mm, from the viewpoints of improving the heat insulating effect between the friction material 10 and the back plate 30 and effectively suppressing cracks and breakage in the back plate 30.

[0044] Furthermore, in the above-described embodiment, the inner second thick portion 45 has a substantially trapezoidal shape, and the outer second thick portion 47 has a substantially rectangular shape, but 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-diagrams (a) and (b) in Fig. 6, the inner second thick portion 45 (45A, 45B) may have an arc shape or a curved shape that widens toward the inner periphery of the disc rotor, that is, it may have an arc shape or a curved shape that narrows toward the outer periphery of the disc rotor. Furthermore, when the inner second thick portion 45 (45A, 45B) has an arc shape, the center of the arc may be configured to be outside the back plate 30A, as shown in the partial view (a) of Figure 6, or may be configured to be inside the back plate 30B, as shown in the partial view (b) of Figure 6.

[0045] 7, the shape of the inner circumferential 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 circumferential 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 circumferential second thick portion 45D may have a substantially rectangular shape or a polygonal shape with pentagons or more sides.

[0046] Furthermore, for example, as shown in the partial view (a) of Figure 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. Furthermore, for example, as shown in the partial view (b) of Figure 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.

[0047] 9 , the inner second thick portion 45G may include an inner second thick portion side 49 disposed along the side of the back plate main body and a diagonal brace 51 inclined from the inner second thick portion side 49 relative to the radial direction of the disc rotor, and the inner second thick portion side 49 may extend to the inner end of the inner root portion 35B of the disc rotor. By having the inner second thick portion side 49 extend to the end 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 back plate main body 31 and the ear portion 33. Note that the inner second thick portion side 49 may extend at least to the inner end of the inner root portion 35B of the disc rotor, and may extend beyond the inner end of the inner root portion 35B.

[0048] In the above-described embodiment, the inner periphery-side second thick-portion side portions 49 and the diagonal interlocking portions 51 are integrally configured. However, as shown in FIG. 9 , the inner periphery-side second thick-portion side portions 49 and the diagonal interlocking portions 51 can be separately provided, thereby further reducing the weight of the back plate 30G while maintaining its durability. In the back plate 30G according to this modification, the diagonal interlocking portions 51 are formed to have a substantially rectangular shape and are not curved. However, at least a portion of the diagonal interlocking portions 51 may have a curved shape. That is, the diagonal interlocking portions 51 may be configured to be curved, for example, in a hook shape. Alternatively, the inner periphery-side second thick-portion side portions 49 and the diagonal interlocking portions 51 may be configured to have a substantially U-shape.

[0049] In addition, 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 portion 33 opposite the backplate main body portion to the inner second thick portion 47 is the distance from the side 37 of the ear portion 33 opposite the backplate main body portion to the end of the diagonal cross section 51 on the central side of the backplate main body portion 31, as shown in Figure 9.

[0050] It is clear from the claims that the technical scope of the present invention includes forms to which the above-mentioned modifications or improvements have been made. [Explanation of symbols]

[0051] 100: Disc brake pads, 10:Friction material, 20: disc rotor, 30 (30A, 30B, 30C, 30D, 30E, 30F): Back plate, 31: Back plate main body, 33: Ear, 35 (35A, 35B): Base, 37: Side of back plate main body opposite, 39: Non-thick portion 40(40A,40B,40C,40D,40E,40F,40G):Thick wall part, 41:First thick wall part, 43(43A,43B,43C,43D,43E,43F,43G):Second thick wall part Part, 45 (45A, 45B, 45C, 45D, 45', 45G): Inner peripheral side second thick wall part, 47 (47A, 47B): Outer peripheral side second thick wall part, 49: Inner peripheral side second thick wall part side part, 51: Bracing part, 70: Torque receiving member, 71: Ear holding part, D1: distance, D2: distance, EL: extension line of the connection point between the inner second thick-walled part and the outer second thick-walled part

Claims

1. 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.

2. 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.

3. The disc brake pad according to claim 2 , wherein the inner circumferential second thick portion includes a diagonal portion inclined from a side portion of the inner circumferential second thick portion relative to a radial direction of the disc rotor.

4. The disc brake pad according to claim 3 , wherein the side portion of the inner circumferential second thick portion and the diagonal portion are integral with each other.

5. 5. The disc brake pad according to claim 3 or 4, wherein the diagonal portion does not have a curved shape.

6. The disc brake pad according to claim 3 or 4, wherein the diagonal cross section has at least a portion thereof curved.

7. 7. The disc brake pad according to claim 1, 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. 8. The disc brake pad according to claim 1, wherein the back plate is made of at least one material selected from the group consisting of an iron alloy, an aluminum alloy, an aluminum composite material, and a magnesium alloy.

9. 9. The disc brake pad according to claim 8, wherein the back plate is made of an aluminum alloy or an aluminum composite material, the aluminum alloy or the aluminum composite material having a Cu content of 1% or less and a Mg content of 3% or less, and not belonging to a high-strength aluminum alloy.

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