JP6859285B2 - Friction members and brake pads - Google Patents

Description

The present invention relates to friction members and brake pads.

Patent Document 1 discloses a friction member for a brake pad. It is desirable that such a friction member has high wear resistance even in a high temperature region.

Japanese Unexamined Patent Publication No. 5-86359

An object of the present invention is to provide a friction member and a brake pad having high wear resistance even in a high temperature region.

The friction member according to the first aspect of the present invention has a friction surface configured to be in contact with a rotating body and contains an intermetallic compound produced from cobalt and titanium.
According to the friction member on the first side surface, by including such an intermetallic compound, the strength increases as the temperature rises, and high wear resistance can be realized even in a high temperature region.

In the friction member of the second side surface according to the first side surface, the intermetallic compound contains Co ₃ Ti.
According to the friction member on the second side _{surface, by including Co 3} Ti, the strength increases as the temperature rises, and high wear resistance can be realized even in a high temperature region.

In the friction member of the third side surface according to the first or second side surface, the first dimension of the friction surface in the first direction parallel to the friction surface is 15 mm or more and 30 mm or less.
According to the friction member on the third side surface, the first dimension is set to 15 mm or more to maintain braking performance, and the first dimension is set to 30 mm or less to form a compact structure.

In the friction member of the fourth side surface according to the third side surface, the second dimension of the friction surface in the second direction parallel to the friction surface and perpendicular to the first direction is 10 mm or more and 20 mm or less.
According to the friction member on the fourth side surface, the braking property can be maintained by setting the second dimension to 10 mm or more, and the compact configuration can be achieved by setting the second dimension to 20 mm or less.

In the friction member of the fifth side surface according to the fourth side surface, the second dimension is smaller than the first dimension.
According to the friction member on the fifth side surface, the rotating body can be suitably contacted by increasing the first dimension along the rotation direction of the rotating body.

The friction member on the sixth side surface according to any one of the third to fifth side surfaces is curved so as to form irregularities in the first direction.
According to the friction member on the sixth side surface, the friction surface can be arranged along the rotation direction of the rotating body, and the braking performance can be improved.

In the friction member on the seventh side surface according to any one of the first to sixth side surfaces, the third dimension of the friction member in the third direction perpendicular to the friction surface is 1.5 mm or more and 5 mm or less. ..
According to the friction member on the seventh side surface, the strength can be secured by setting the third dimension to 1.5 mm or more, and the third dimension can be set to 5 mm or less to form a compact structure.

In the friction member of the eighth side surface according to any one of the first to seventh side surfaces, the first volume ratio of cobalt used for producing the intermetallic compound to the total material is set to 5% or more and 40% or less. To.
According to the friction member on the eighth side surface, a suitable frictional force can be generated between the rotating body and the friction member.

In the friction member on the ninth side surface according to any one of the first to eighth side surfaces, the second volume ratio of titanium used for producing the intermetallic compound to the total material is set to 5% or more and 40% or less. To.
According to the friction member on the ninth side surface, a suitable frictional force can be generated between the rotating body and the friction member.

In the friction member of the tenth side surface according to the ninth side surface, the first volume ratio of cobalt used for producing the intermetallic compound to the total material is the second volume of titanium used for producing the intermetallic compound with respect to all the materials. Different from the ratio.
According to the friction member on the tenth side surface, a suitable frictional force can be generated between the rotating body and the friction member.

In the friction member of the eleventh side surface according to the tenth side surface, the first volume ratio is larger than the second volume ratio.
According to the friction member on the eleventh side surface, a suitable frictional force can be generated between the rotating body and the friction member.

In the friction member of the twelfth side surface according to any one of the first to eleventh side surfaces, the first mass ratio of cobalt used for producing the intermetallic compound to the total material is set to 30% or more and 70% or less. To.
According to the friction member on the twelfth side surface, a suitable frictional force can be generated between the rotating body and the friction member.

In the friction member of the 13th side surface according to any one of the 1st to 12th side surfaces, the second mass ratio of titanium used for producing the intermetallic compound to the total material is set to 5% or more and 20% or less. To.
According to the friction member on the thirteenth side surface, a suitable frictional force can be generated between the rotating body and the friction member.

In the friction member of the 14th side surface according to the 13th side surface, the first mass ratio of cobalt used for producing the intermetallic compound to the total material is the second mass ratio of titanium used for producing the intermetallic compound with respect to all the materials. Different from the ratio.
According to the friction member on the 14th side surface, a suitable frictional force can be generated between the rotating body and the friction member.

In the friction member on the fifteenth side surface that follows the fourteenth side surface, the first mass ratio is larger than the second mass ratio.
According to the friction member on the fifteenth side surface, a suitable frictional force can be generated between the rotating body and the friction member.

The friction member of the 16th side surface according to any one of the 1st to 15th side surfaces further contains a friction modifier.
According to the friction member on the 16th side surface, the frictional force with respect to the rotating body can be suitably adjusted.

The friction member on the 17th side surface according to any one of the 1st to 16th side surfaces further contains a grinding agent.
According to the friction member on the 17th side surface, braking performance can be improved.

The friction member on the 18th side surface according to any one of the 1st to 17th side surfaces further contains a volume adjusting agent.
According to the friction member on the 18th side surface, a suitable volume can be obtained.

The brake pad on the 19th side surface includes a friction member according to any one of the 1st to 18th side surfaces, and a back plate that supports the friction member.
According to the brake pad on the 19th side surface, it can be easily attached to the brake caliper of the bicycle.

In the brake pad on the 20th side surface according to the 19th side surface, the friction member is diffusively joined to the back plate.
According to the brake pad on the 20th side surface, the friction member can be suitably connected to the back plate.

In the brake pad on the 21st side surface that follows the 19th side surface, the friction member is mechanically joined to the back plate.
According to the brake pad on the 21st side surface, the friction member can be suitably connected to the back plate.

In the brake pads on the 22nd side surface according to the 19th to 21st side surfaces, the back plate is formed of any of iron alloy, titanium, titanium alloy, and aluminum alloy.
According to the brake pad on the 22nd side surface, high rigidity can be obtained.

In the brake pad on the 23rd side surface according to the 19th to 22nd side surfaces, the back plate includes a support portion for supporting the friction member and a heat radiating portion having a heat radiating structure.
According to the brake pad on the 23rd side surface, heat generation during braking can be suppressed.

In the brake pad on the 24th side according to the 23rd, the heat dissipation structure includes fins.
According to the brake pad on the 24th side surface, since the heat dissipation structure is simple, it can be easily manufactured.

The friction member and brake pad of the present invention have high wear resistance in a high temperature range.

The perspective view of the brake pad of 1st Embodiment. The plan view of the brake pad of 1st Embodiment. The side view of the brake pad of 1st Embodiment. The schematic diagram for demonstrating the first example of the manufacturing method of a brake pad. The schematic diagram for demonstrating the 2nd example of the manufacturing method of a brake pad. The schematic diagram for demonstrating the 2nd example of the manufacturing method of a brake pad. The schematic diagram for demonstrating the 3rd example of the manufacturing method of a brake pad. The schematic diagram for demonstrating the 3rd example of the manufacturing method of a brake pad. The graph which shows the wear amount of the comparative example, Example 1 and Example 2. The chart which shows the dynamic friction coefficient of the comparative example, Example 1 and Example 2. The graph which shows the friction amount of the comparative example and Examples 1, 3 to 6. The chart which shows the dynamic friction coefficient of the comparative example and Examples 1, 3 to 6. A perspective view of a modified example of the brake pad. FIG. 3 is a perspective view of a modified example of the brake pad viewed from a viewpoint different from that of FIG.

(Embodiment)
The brake pad 10 according to the embodiment of the present invention will be described with reference to FIGS. 1 to 3.
The brake pad 10 is attached to, for example, a human-powered vehicle. Here, the human-powered vehicle means a vehicle that uses human power at least partially with respect to a driving force for traveling, and includes a vehicle that electrically assists human power. Vehicles that use only driving forces other than human power are not included in human-powered vehicles. In particular, vehicles that use only an internal combustion engine as a driving force are not included in human-powered vehicles. Normally, a small light vehicle is assumed as a human-powered vehicle, and a vehicle that does not require a license to drive on a public road is assumed. The human-powered vehicle includes a bicycle propelled only by human power, a bicycle (e-bike) that assists human power by using electric energy, and a unicycle, two-wheeled vehicle, and tricycle that propel by using only electric energy. The brake pad 10 is attached to the rotating shaft of the wheel and brakes a rotating body that rotates in synchronization with the wheel. The rotating body includes, for example, a disc brake rotor. The brake pad 10 has a friction surface 12A (see below) that comes into contact with a braking surface that is at least one surface that intersects the rotation center axis of the rotating body. The brake pad 10 reduces the rotational speed of the rotating body by contacting the friction surface 12A of the brake pad 10 with the braking surface of the rotating body. The "rotating body" in the embodiment means a disc brake rotor (not shown).

As shown in FIGS. 1 and 2, the brake pad 10 includes a friction member 12 and a back plate 14 that supports the friction member 12.

The back plate 14 includes a support portion 16 that supports the friction member 12, and a connecting portion 18 that extends from the support portion 16 and is connected to the brake caliper.
The support portion 16 has a first surface 16A facing the rotating body and a second surface 16B opposite to the first surface 16A in a state where the back plate 14 is attached to the brake caliper of the human-powered vehicle. (See FIG. 3). The friction member 12 is joined to the first surface 16A. Preferably, the first surface 16A is parallel to the friction surface 12A described below. The connecting portion 18 has a through hole 18A. The brake pad 10 is attached to the brake caliper by passing a pin of the brake caliper (not shown) through the through hole 18A. The back plate 14 is formed of any of iron alloys including stainless steel alloys, titanium, titanium alloys, and aluminum alloys.

Next, the friction member 12 will be described. The friction member 12 has a friction surface 12A configured to be in contact with the rotating body and contains an intermetallic compound produced from cobalt and titanium. Preferably, the area of the friction surface 12A is 150 mm ² or more and 600 mm ² or less. More preferably, the area of the friction surface 12A is 250 mm ² or more and 500 mm ² or less. Preferably, the first dimension L1 (see FIG. 2) of the friction surface 12A in the first direction D1 parallel to the friction surface 12A is 15 mm or more and 30 mm or less. Preferably, the second dimension L2 of the friction surface 12A in the second direction D2, which is parallel to the friction surface 12A and perpendicular to the first direction D1, is 10 mm or more and 20 mm or less. Preferably, in the friction member 12, the second dimension L2 is preferably smaller than the first dimension L1. Preferably, the third dimension L3 (see FIG. 3) of the friction member 12 in the third direction D3 perpendicular to the friction surface 12A is 1.5 mm or more and 5 mm or less.

The friction member 12 is arranged so that the second direction D2 of the friction member 12 is along the radial direction perpendicular to the rotation center axis of the rotating body with the back plate 14 attached to the brake caliper of the human-powered vehicle. As a result, the first direction D1, which is the longitudinal direction of the friction member 12, can be substantially along the rotation direction of the rotating body. As shown by the broken line in FIG. 2, the friction member 12 may be curved so as to form an unevenness in the first direction D1. As a result, the friction member 12 is further aligned with the rotation direction of the rotating body.

The friction member 12 further includes tapered surfaces 12B and 12C. The tapered surfaces 12B and 12C are continuously provided on the friction surface 12A. The first tapered surface 12B is inclined from the friction surface 12A toward the support portion 16 of the back plate 14. The first tapered surface 12B extends from the edge of the friction surface 12A opposite to the connecting portion 18 in the second direction D2. The second tapered surface 12C extends from the edge of the friction surface 12A on the connecting portion 18 side in the second direction D2.

The friction member 12 contains an intermetallic compound produced from cobalt and titanium, as described above. _{The friction member 12 contains Co 3} Ti, Co ₂ Ti- (C36), Co ₂ Ti- (C15), Co ₂ Ti (c), and Co ₂ Ti (h) as intermetallic compounds produced from cobalt and titanium. , CoTi, and CoTi ₂ may be included. The intermetallic compound preferably contains _{Co 3 Ti.}

Preferably, in the material for forming the friction member 12, the first volume ratio of cobalt used for producing the intermetallic compound to the total material is set to 5% or more and 40% or less.
Preferably, in the material for forming the friction member 12, the second volume ratio of titanium used for producing the intermetallic compound to the total material is set to 5% or more and 40% or less.
Preferably, in the material for forming the friction member 12, the first volume ratio of cobalt used for the formation of the intermetallic compound to the total material is the second volume ratio of the titanium used for the formation of the intermetallic compound to the total material. different. Preferably, the first volume ratio is larger than the second volume ratio. By making the first volume ratio of cobalt larger than the second volume ratio of titanium, Co ₃ Ti can be efficiently produced.

Preferably, in the material for forming the friction member 12, the first mass ratio of cobalt used for producing the intermetallic compound to the total material is set to 30% or more and 70% or less. Preferably, in the material for forming the friction member 12, the second mass ratio of titanium used for producing the intermetallic compound to the total material is set to 5% or more and 20% or less. Preferably, in the material for forming the friction member 12, the first mass ratio of cobalt used in the formation of the intermetallic compound to the total material is the second mass ratio of titanium used in the formation of the intermetallic compound to the total material. different. Preferably, the first mass ratio is greater than the second mass ratio. By making the first mass ratio of cobalt larger than the second mass ratio of titanium, Co ₃ Ti can be efficiently produced.

The friction member 12 preferably contains at least one of the following materials in addition to titanium and cobalt. For example, the friction member 12 further contains a friction modifier. The friction modifier adjusts the coefficient of dynamic friction between the friction member 12 and the rotating body. The friction modifier adjusts the frictional force of the friction member 12 with respect to the rotating body. Friction modifiers include graphite, coke, molybdenum disulfide, and antimony trifluent. One or more of these substances are selected and used as a friction modifier. In order to make the slidability of the friction member 12 with respect to the rotating body appropriate, the volume ratio of the friction modifier in the formation of the friction member 12 is preferably 10% or more and 60% or less. Further, the mass ratio of the friction modifier in the formation of the friction member 12 is preferably 5% or more and 20% or less.

Preferably, the friction member 12 further contains a grinding agent. The grinding agent improves the braking property due to the contact between the friction member 12 and the rotating body. Grinding agents include mullite, zircon, and sericite. One or more of these substances are selected and used as a grinding agent. In order to make the braking property of the friction member 12 appropriate, the volume ratio of the grinding agent in the formation of the friction member 12 is preferably 5% or more and 30% or less. Further, the mass ratio of the grinding agent in the formation of the friction member 12 is preferably 5% or more and 20% or less.

Preferably, the friction member 12 further comprises a volume modifier. The volume adjuster adjusts the volume of the friction member 12. By adding the volume adjusting agent, the volume of the friction member 12 and the size of the friction surface 12A can be adjusted. Calcium fluoride (CaF ₂ ) can be mentioned as a volume modifier. In order to achieve both miniaturization of the friction member 12 and braking performance, the volume ratio of the volume adjusting agent in the production of the friction member 12 is preferably 5% or more and 30% or less. Further, the mass ratio of the volume modifier in the formation of the friction member 12 is preferably 5% or more and 15% or less.

Next, the microscopic structure of the friction member 12 will be described. The friction member 12 of the first example contains titanium, cobalt, an intermetallic compound of titanium and cobalt, titanium oxide, and cobalt oxide. The intermetallic compound is considered to be formed on the surfaces of titanium and cobalt. The intermetallic compound is, for example, at least one of Co ₃ Ti, Co ₂ Ti- (C36), Co ₂ Ti- (C15), Co ₂ Ti (c), Co ₂ Ti (h), CoTi, and CoTi _2. It is a Ti—Co-based intermetallic compound containing one. The friction member 12 of the second example includes an additive material in the friction member 12 of the first example. Additive materials include, for example, mullite, zircon, sericite and calcium fluoride. Non-metallic particles may also be included as additive materials. For example, artificial graphite and natural graphite.

The friction member 12 is formed by sintering a material. The material includes a metallic material. Metallic materials include cobalt powder and titanium powder. Preferably, the material comprises an additive material. The additive material is, for example, at least one of mullite, zircon, sericite, and calcium fluoride described above. By burning a workpiece containing cobalt powder and titanium powder, Co ₃ Ti, Co ₂ Ti- (C36), Co ₂ Ti- (C15), Co ₂ Ti (c), Co ₂ Ti (h), CoTi, CoTi ₂ At least one of is formed.

Next, three examples of the connection structure of the friction member 12 in the back plate 14 will be given below. 4 to 8 show the cross-sectional structure of the friction member at a position corresponding to the position of the cross section along the line AA of FIG.

The first example will be described with reference to FIG. The friction member is diffusion-bonded to the back plate 14. The term "diffusion bonding" refers to "a boundary structure is formed by the diffusion of a metal element derived from one of the two metal members into the inside of the other metal member, or a metal derived from the two metal members. Boundary structures are formed by the mutual diffusion of elements, which allows the two metal members to be directly (ie, different from the two metal members, without intervening connecting members such as adhesives and solders). , Inorganic and chemically linked. "

A second example will be described with reference to FIGS. 5 and 6. The friction member is mechanically joined to the back plate 14. Specifically, the friction member 12 has a plurality of engaging portions 12E that engage with the back plate on the back surface 12D on the side opposite to the friction surface 12A. The engaging portion 12E protrudes from the back surface 12D. The back plate 14 has a through hole 14A that engages with the engaging portion 12E. The engaging portion 12E of the friction member 12 is press-fitted into the through hole 14A of the back plate 14, or the engaging portion 12E of the friction member 12 is crushed while being inserted into the through hole 14A of the back plate 14. The friction member 12 and the back plate 14 are coupled.

A third example will be described with reference to FIGS. 7 and 8. The friction member 12 is mechanically joined to the back plate 14, and the friction member 12 is mechanically joined to the back plate 14. In this example, the joining plate 20 is interposed between the friction member 12 and the back plate 14. The friction member is diffusively joined to the joining plate 20. The back plate 14 has a through hole 14B. The joining plate 20 and the back plate 14 are joined by an engaging portion 20A formed by a part of the joining plate 20 flowing into the through hole 14B of the back plate 14 by softening or melting.

A method of manufacturing the brake pad 10a of the first example described above will be described with reference to FIG.
First, in the first step, a work is formed from a material containing at least cobalt powder and titanium powder. The work is obtained by pressure molding the material. The material is in powder form and becomes a friction member 12 containing an intermetallic compound in the next step. The material may include the above-mentioned additive materials in addition to the cobalt powder and the titanium powder.

Next, in the second step, the work is heated without bringing the work into contact with the back plate 14, thereby inducing a combustion synthesis that produces an intermetallic compound in the friction member 12. In this way, the friction member 12 is obtained.

Next, in the third step, the friction member 12 and the back plate 14 are arranged so that the friction surface 12A of the friction member 12 faces outward and the back surface 12D on the opposite side of the friction surface 12A is in contact with the back plate. Brake pads 10a are manufactured by heating and pressurizing the laminate. The heating and pressurizing conditions depend on the material of the friction member 12 and the back plate 14, as long as the pressure and temperature are sufficient to connect the friction member 12 and the back plate 14 at least partially or chemically. It can be appropriately adjusted depending on the composition of the intermetallic compound of the friction member 12 and the material of the back plate 14.

A boundary structure exists at the boundary between the friction member 12 and the back plate 14. Elements derived from the friction member 12 (cobalt, titanium, etc.) and elements derived from the back plate 14 (for example, titanium, aluminum, etc.) coexist in the vicinity of the interface between the friction member 12 and the back plate 14. A boundary structure is formed by diffusing elements derived from one of the friction member 12 and the back plate 14 (for example, the friction member 12) into the inside of the other (for example, the back plate) of the friction member 12 and the back plate. A boundary structure is formed over a depth range of about 0 μm to 100 μm. The presence of the boundary structure indicates that the friction member 12 and the back plate 14 are connected, at least partially, inorganically and chemically by diffusion bonding.

A method of manufacturing the brake pad 10b of the second example described above will be described with reference to FIGS. 5 and 6.
First, in the first step, as in the first example, the work WK is formed from a material containing at least cobalt powder and titanium powder. Work WK is obtained by pressure molding the material. At the time of pressure molding, an engaging portion is provided on the work WK.

In the second step, the work WK is heated without contacting the work WK with the back plate 14 to induce a combustion synthesis that produces an intermetallic compound in the friction member 12. In this way, the friction member 12 is obtained.

In the third step, the friction member 12 and the back plate 14 are arranged so that the friction surface 12A of the friction member 12 faces outward and the engaging portion 12E is inserted into the through hole 14A of the back plate 14, and the laminated body is formed. To form. Then, the portion of the engaging portion 12E of the friction member 12 protruding from the through hole 14A is crushed, and the engaging portion 12E and the back plate 14 are engaged with each other. Further, preferably, a diffusion bond may be formed at the boundary portion between the friction member 12 and the back plate 14 by heat-treating the work WK in which the friction member 12 and the back plate 14 are engaged.

A method of manufacturing the brake pad 10c of the third example described above will be described with reference to FIGS. 7 and 8.
In the first step, as in the first example, the work WK is formed from a material containing at least cobalt powder and titanium powder. Work WK is obtained by pressure molding the material.
In the second step, the work WK, the joining plate 20, and the back plate 14 are arranged in a three-layer laminated body. Here, the work WK, the joint plate 20, and the back plate 14 are arranged so that the joint plate 20 is in contact with the work WK and the back plate 14. The joining plate 20 is a flat plate containing aluminum.

In the third step, the friction member 12 is obtained by heating the work WK. The work WK is heated so that an intermetallic compound is produced in the friction member 12 by combustion synthesis from at least any two of the plurality of metal materials. Combustion synthesis is started by applying an external thermal stimulus to the work WK so that a combustion reaction, which is an exothermic reaction, is induced locally in the work WK. Specifically, the combustion reaction is started by irradiating the work WK with a laser and locally heating the work WK. For example, an external thermal stimulus applied to one end of the work WK (the upper surface opposite the bonding plate) induces a combustion reaction at one end. The combustion reaction proceeds in a chain from one end to the other end (for example, the lower surface in contact with the joining plate) of the work WK. Combustion synthesis is completed in an extremely short time, does not require continuous heating from the outside, and the amount of heating energy supplied from the outside is extremely small. Therefore, the manufacturing cost of the friction member 12 can be significantly reduced.

The heating in the third step, that is, the local application of an external thermal stimulus, not only causes the formation of the friction member 12, but also the formation of a chemical connection between the friction member 12 and the joining plate, and the joining plate 20 and the back. Causes the formation of a mechanical connection with the plate 14. For example, the heat associated with the combustion synthesis of the intermetallic compound of the friction member 12 is generated at the boundary between the work WK and the joint plate 20 by at least one of the materials of the work WK (for example, cobalt) and the metal of the joint plate 20 (this example). Then, a second combustion reaction with aluminum) is induced. The friction member 12 and the back plate 14 are inorganically and chemically linked by the compound produced by the second combustion reaction. Further, a part of the bonding plate 20 is softened or melted by the heat associated with the fuel synthesis of the compound. A part of the softened or melted joint plate 20 flows into the through hole 14B of the back plate 14 to form the engaging portion 20A. The engaging portion 20A and the through hole 14B function as a mechanical joining portion that mechanically connects the joining plate 20 and the back plate 14.

In this way, by applying an external thermal stimulus to one end of the work WK (the upper surface on the opposite side of the joining plate), the friction member 12 is generated, the friction member 12 is chemically connected to the joining plate, and the joining plate is formed. A sequence involving mechanical coupling between 20 and the back plate 14 proceeds in a chain or automatic manner. This sequence ends automatically upon completion of the combustion reaction. In this way, the brake pad 10c is manufactured. As described above, the combustion synthesis is completed in an extremely short time, continuous heating from the outside is not required, and the amount of heating energy supplied from the outside is extremely small. Therefore, the manufacturing cost of the brake pad 10c is significantly reduced.

<Example>
Hereinafter, examples of the friction member 12 will be described in comparison with comparative examples.
Tables 1 and 2 show the compositions of Examples 1 to 6 and the compositions of Comparative Examples in the materials. The values shown in the compositions in Table 1 are the volume ratios of the respective materials when forming the friction members 12 according to Examples 1 to 6 and Comparative Examples. The values shown in the compositions in Table 2 are the mass ratios of the materials for the same Examples and Comparative Examples as in Table 1. The friction members 12 of Examples 1 to 6 and the friction members of Comparative Examples are all made by firing a workpiece mixed with materials at a temperature of 870 ° C.

Separately from Examples 1 to 6, a powder sintered body of 76% cobalt and 24% titanium was formed in terms of the volume ratio of the material. The firing temperature at the time of forming the powder sintered body was set to 870 ° C. According to X-ray diffraction (XRD) of this powder sintered body, a peak of Co ₃ Ti was obtained in addition to the peak of titanium and the peak of cobalt. As can be seen from the results described later, the presence of an intermetallic compound of titanium and cobalt (eg, Co ₃ Ti) improves the wear resistance and dynamic friction coefficient of the friction member.

A comparative example is a conventional friction member that does not contain titanium and cobalt.
The composition of Example 1 is as shown in Tables 1 and 2.
The volume ratio of titanium and cobalt in Example 2 is different from that in Example 1. The composition of the additive material in Example 2 is the same as the composition of the additive material in Example 1 in terms of volume ratio.
Examples 3 to 6 have the following configurations as compared with Example 1. In the order of Example 3 to Example 6, the volume ratio of the total amount of graphite (natural, crystalline) and graphite (artificial) to the total volume is large, and on the contrary, with cobalt. The volume ratio of the total amount of graphite is decreasing in order. The volume ratio of cobalt to titanium is equal to the volume ratio of cobalt to titanium of Example 1. In Examples 1-6 and Comparative Examples, the volume ratios of mullite, zircon and sericite are equal.

The effects of Examples 1 to 6 are shown with reference to FIGS. 9 to 12. Examples 1 to 6 and Comparative Example were compared in terms of wear amount and coefficient of kinetic friction.
FIG. 9 is a graph showing the amount of wear for Comparative Example (without heat radiating portion) and Examples 1 and 2.
FIG. 10 is a graph showing the time change of the dynamic friction coefficient for Comparative Example (without heat radiating portion) and Examples 1 and 2.
FIG. 11 is a graph showing the amount of wear for Comparative Example (with a heat radiating portion) and Examples 1, 3 to 6.
FIG. 12 is a graph showing the time change of the dynamic friction coefficient for Comparative Example (with a heat radiating portion) and Examples 1, 3 to 6.
The comparative examples of FIGS. 11 and 12 have a heat radiating portion. Except for the comparative examples of FIGS. 11 and 12, none of them has a heat radiating portion.

The amount of wear and the coefficient of dynamic friction were measured under the following conditions. The friction area of the friction member 12 of the examples and the reference examples is 822.4 mm ² . Shimano (SMRT81S) was used as the rotating body. The rotation speed was set to 240 rpm (equivalent to 30 km / h), the force of the brake caliper (BRM820 manufactured by Shimano) was set to 735 N, and a drag test was conducted for 30 minutes. According to this condition, the load is higher than that of normal braking. Specifically, according to the above conditions, the temperature of the friction member 12 is 580 ° C to 650 ° C.

As a result of the above test, the amount of wear of the friction member 12 of Examples 1 to 6 was less than the amount of wear of the friction member of Comparative Example.
Comparing the above-mentioned Example 1 and Example 2, the amount of wear of Example 1 is smaller than that of Example 2. From this, it can be seen that it is preferable that the volume ratio of cobalt is larger than the volume ratio of titanium in the material.

The coefficient of kinetic friction of the friction members 12 of Examples 1 to 6 is smaller than that of the comparative example with the passage of time. As can be seen by comparing Examples 1 to 6, as the graphite content increases, the decrease in the coefficient of kinetic friction with the passage of time increases.

(Modification example)
The description of the above embodiment is an example of possible forms of the friction member and the brake pad according to the present invention, and is not intended to limit the form. The friction member and the brake pad according to the present invention may take, for example, a modification of the above embodiment shown below and a combination of at least two modifications that do not contradict each other. In the following modification, the parts common to the embodiment are designated by the same reference numerals as those in the embodiment, and the description thereof will be omitted.

An example of the brake pad 30 having a heat dissipation structure will be described with reference to FIGS. 13 and 14. The brake pad 30 includes a friction member 32 and a back plate 34. The friction member 32 has a structure and composition similar to that of the friction member 12 of the embodiment. The back plate 34 includes a support portion 36 that supports the friction member 32 and a heat radiating portion 38 having a heat radiating structure.

The support portion 36 and the heat dissipation portion 38 are provided on the main body 40. The main body 40 has a first surface 40A facing the rotating body and a second surface 40B opposite to the first surface 40A in a state where the back plate 34 is attached to the brake caliper of the human-powered vehicle. The friction member 32 is joined to the first surface 40A at the support portion 36 of the main body 40. The heat radiating portion 38 is provided on the second surface 40B of the main body 40 so as not to be located on the opposite side of the friction member 32. In other words, the heat radiating portion 38 is provided on the main body 40 so as not to face the friction member 32 via the main body 40. The heat radiating portion 38 may be formed integrally with the main body 40 or may be formed separately. In the present embodiment, the heat radiating portion 38 is integrally formed with the main body 40.

As described above, the heat radiating unit 38 has a heat radiating structure. The heat dissipation structure includes fins 42. A plurality of fins 42 are provided on the second surface 40B of the main body 40. Each of the plurality of fins 42 is provided so as to extend from the second surface 40B on the side opposite to the friction member 32. The fins 42 may be formed integrally with the main body 40 or may be formed separately. In this embodiment, the fins 42 are integrally formed with the main body 40. When the fins 42 are formed separately, for example, a hole for inserting the fin 42 may be provided in the main body 40, and the fin 42 may be fixed to the hole by press fitting or adhesion. Further, the main body 40 is provided with a through hole 40C for passing the pin of the brake caliper between the support portion 36 and the heat radiating portion 38.

-In the above embodiment, the friction surface 12A may be divided into a plurality of parts. For example, the friction surface 12A is divided into two parts. A gap is formed between the two friction surfaces forming the friction surface 12A. In this case, the friction area is calculated by the sum of the areas of the two friction surfaces. Further, in this case, the first dimension L1 and the second dimension L2 of the friction member 12 are set with respect to the outer shape when a plurality of friction surfaces are regarded as continuous surfaces.

-The human-powered vehicle to which the brake pads 10, 10a, 10b, 10c, 30 according to the embodiment are attached is not limited. Human-powered vehicles include road bikes, mountain bikes, cross bikes, city cycles, cargo bikes, recumbent bikes and kick skaters.

L1 ... 1st dimension, L2 ... 2nd dimension, L3 ... 3rd dimension, 10 ... Brake pad, 10a ... Brake pad, 10b ... Brake pad, 10c ... Brake pad, 12 ... Friction member, 12A ... Friction surface, 14 ... Back plate, 16 ... support part, 30 ... brake pad, 22 ... friction member, 24 ... metal compound, 34 ... back plate, 36 ... support part, 38 ... heat dissipation part, 42 ... fin.

Claims (23)

It has a friction surface configured to come into contact with a rotating body that rotates synchronously with the wheels of a human-powered vehicle.
An intermetallic compound formed from cobalt and titanium seen including,
The intermetallic compound is a friction member containing _{Co 3 Ti.} The friction member according to claim 1 , wherein the first dimension of the friction surface in the first direction parallel to the friction surface and substantially along the rotation direction of the rotating body is 15 mm or more and 30 mm or less. The second dimension of the friction surface in a second direction perpendicular to and parallel to the first direction relative to the friction surface is 10mm or more 20mm or less, the friction member according to claim 2. The second dimension is the smaller than the first dimension, the friction member according to claim 3. Curved so as to form unevenness in the first direction, the friction member according to any one of claims 2-4. The third dimension of the friction member in a third direction perpendicular to the friction surface is 1.5mm 5mm or more or less, the friction member according to any one of claims 1 to 5. Wherein the first volume ratio to the total material of cobalt used for the generation of the intermetallic compound is set at 40% or less than 5%, the friction member according to any one of claims 1 to 6. The second volume ratio to the total material of the titanium used in the generation of the intermetallic compound is set at 40% or less than 5%, the friction member according to any one of claims 1 to 7. The first volume ratio to the total material of cobalt used for the generation of the intermetallic compound is different from the second volume ratio to the total material of the titanium used in the generation of the intermetallic compound, the friction according to請Motomeko 8 Element. Wherein the first volume ratio, the second greater than the volume ratio, the friction member according to claim 9. The first mass ratio to the total material of the cobalt used for the generation of the intermetallic compound is set to 70% or less than 30%, the friction member according to any one of claims 1 to 10. The second mass ratio to the total material of the titanium used in the generation of the intermetallic compound is set to 20% or less than 5%, the friction member according to any one of claims 1 to 11. The first mass ratio to the total material of the cobalt used for the generation of the intermetallic compound is different from the second mass ratio to the total material of the titanium used in the generation of the intermetallic compound, the friction according to請Motomeko 12 Element. Wherein the first mass ratio, the greater than the second mass ratio, the friction member according to claim 13. The friction member according to any one of claims 1 to 14 , further comprising a friction modifier. The friction member according to any one of claims 1 to 15 , further comprising a grinding agent. The friction member according to any one of claims 1 to 16 , further comprising a volume modifier. The friction member according to any one of claims 1 to 17,
Including a back plate for supporting the friction member, the brake pad. Said friction member, wherein are diffusion-bonded to the back plate, a brake pad according to claim 18. It said friction member, said back plate being mechanically joined, brake pad according to claim 18. The back plate is an iron alloy, titanium, titanium alloy, and are formed by any of aluminum alloy, a brake pad according to any one of claims 18 to 20. The back plate includes a support portion for supporting the friction member, and a heat radiating portion having a heat radiation structure, a brake pad according to any one of claims 18 to 21. The radiator structure includes a fin, a brake pad according to claim 22.

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