JP2019168058A - Friction member and brake pad - Google Patents

Abstract

To provide a friction member and brake pad which have excellent abrasion resistance in a high-temperature range.SOLUTION: A friction member has a friction surface configured to come into contact with a rotation body, and includes an intermetallic compound produced from cobalt and titanium.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a friction member and a brake pad.

  Patent Document 1 discloses a friction member for a brake pad. Such a friction member desirably has high wear resistance even in a high temperature range.

JP-A-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 range.

The friction member according to the first aspect of the present invention has a friction surface configured to be in contact with the rotating body, and includes an intermetallic compound generated from cobalt and titanium.
According to the friction member of 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 range.

In the friction member on the second side according to the first side, 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 with increasing temperature, and high wear resistance can be realized even in a high temperature range.

In the friction member on the third side according to the first or second side, the first dimension of the friction surface in a 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, while maintaining the braking performance, and the first dimension is set to 30 mm or less, the compact configuration can be achieved.

In the friction member on the fourth side according to the third side, a second dimension of the friction surface in a 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, a compact configuration can be achieved by setting the second dimension to 20 mm or less while maintaining the braking performance by setting the second dimension to 10 mm or more.

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

The friction member on the sixth side according to any one of the third to fifth sides 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 according to any one of the first to sixth sides, the third dimension of the friction member in a 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 third dimension is set to 1.5 mm or more, while ensuring the strength, and the third dimension is set to 5 mm or less, it can be made compact.

In the friction member of the eighth side according to any one of the first to seventh sides, the first volume ratio with respect to the total material of cobalt used for generating the intermetallic compound is set to 5% or more and 40% or less. The
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 according to any one of the first to eighth sides, the second volume ratio with respect to the total material of titanium used for generating the intermetallic compound is set to 5% to 40%. The
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 according to the ninth aspect, the first volume ratio with respect to the total material of cobalt used for generating the intermetallic compound is the second volume with respect to the total material of titanium used for generating the intermetallic compound. It is 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 on the eleventh side according to the tenth side, 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 according to any one of the first to eleventh sides, the first mass ratio with respect to the total material of cobalt used for generating the intermetallic compound is set to 30% or more and 70% or less. The
According to the friction member on the twelfth side surface, a suitable friction force can be generated between the rotating body and the friction member.

In the friction member of the thirteenth side according to any one of the first to twelfth sides, the second mass ratio with respect to the total material of titanium used for generating the intermetallic compound is set to 5% or more and 20% or less. The
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 fourteenth side according to the thirteenth side, the first mass ratio with respect to the total material of cobalt used for generating the intermetallic compound is the second mass with respect to the total material of titanium used for generating the intermetallic compound. It is different from the ratio.
According to the friction member on the fourteenth side surface, a suitable friction force can be generated between the rotating body and the friction member.

In the friction member on the fifteenth side according to the fourteenth side, the first mass ratio is greater 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 on the sixteenth side according to any one of the first to fifteenth sides further includes a friction modifier.
According to the friction member on the sixteenth side surface, the frictional force against the rotating body can be suitably adjusted.

The friction member on the seventeenth side according to any one of the first to sixteenth sides further includes an abrasive.
According to the friction member on the seventeenth side surface, the braking performance can be improved.

The friction member on the eighteenth side according to any one of the first to seventeenth sides further includes a volume adjusting agent.
According to the friction member on the eighteenth side surface, a suitable volume can be obtained.

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

In the brake pad on the twentieth side according to the nineteenth side, the friction member is diffusion bonded to the back plate.
According to the brake pad of the twentieth side surface, the friction member can be suitably coupled to the back plate.

In the brake pad on the twenty-first side according to the nineteenth side, the friction member is mechanically joined to the back plate.
According to the brake pad on the twenty-first side surface, the friction member can be suitably coupled to the back plate.

In the brake pad on the twenty-second side according to the nineteenth to twenty-first sides, the back plate is formed of any one of iron alloy, titanium, titanium alloy, and aluminum alloy.
According to the brake pad of the 22nd side, high rigidity is 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 that supports the friction member and a heat dissipation portion having a heat dissipation structure.
According to the brake pad on the twenty-third side, heat generation during braking can be suppressed.

In the twenty-fourth side brake pad according to the twenty-third aspect, the heat dissipation structure includes a fin.
According to the brake pad of the 24th side, since the heat dissipation structure is simple, it can be easily manufactured.

  The friction member and the brake pad of the present invention have high wear resistance at high temperatures.

The perspective view of the brake pad of 1st Embodiment. The top view of the brake pad of 1st Embodiment. The side view of the brake pad of 1st Embodiment. The schematic diagram for demonstrating the 1st 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 abrasion loss of a comparative example, Example 1, and Example 2. FIG. The chart which shows the dynamic friction coefficient of a comparative example, Example 1, and Example 2. FIG. The graph which shows the friction amount of a comparative example and Examples 1, 3-6. The chart which shows the dynamic friction coefficient of a comparative example and Examples 1, 3-6. The perspective view of the modification of a brake pad. The perspective view of the modification of the brake pad seen from the viewpoint different from FIG.

(Embodiment)
With reference to FIGS. 1-3, the brake pad 10 of one Embodiment of this invention is demonstrated.
The brake pad 10 is attached to a human-powered vehicle, for example. Here, the human-powered vehicle means a vehicle that uses human power at least partially with respect to the driving force for traveling, and includes a vehicle that assists human power by electric drive. Vehicles that use only motive power other than human power are not included in human-powered vehicles. In particular, a vehicle using only an internal combustion engine as a driving force is not included in a manpower driven vehicle. Usually, a man-powered vehicle is assumed to be a small light vehicle and a vehicle that does not require a license for driving on a public road. Human-powered vehicles include bicycles that are propelled only by human power, bicycles that assist human power using electric energy (e-bike), unicycles, two-wheeled vehicles, and tricycles that are propelled using only electric energy. The brake pad 10 is attached to a rotating shaft of a wheel and brakes a rotating body that rotates in synchronization with the wheel. As an example, the rotating body includes a disc brake rotor. The brake pad 10 has a friction surface 12A (see later) that contacts 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 contact between the friction surface 12A of the brake pad 10 and the braking surface of the rotating body. The “rotary 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 connection 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 a brake caliper of a 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 a friction surface 12A described later. The connecting portion 18 has a through hole 18A. The brake pad 10 is attached to the brake caliper by passing a pin of a brake caliper (not shown) through the through hole 18A. The back plate 14 is formed of any one of an iron alloy including a stainless alloy, titanium, a titanium alloy, and an aluminum alloy.

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 includes an intermetallic compound generated 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 not less than 15 mm and not more than 30 mm. Preferably, the second dimension L2 of the friction surface 12A in the second direction D2 parallel to the friction surface 12A and perpendicular to the first direction D1 is not less than 10 mm and not more than 20 mm. 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 such that the second direction D2 of the friction member 12 is along a radial direction perpendicular to the rotation center axis of the rotating body in a state where the back plate 14 is attached to the brake caliper of the manpowered vehicle. As a result, the first direction D1, which is the longitudinal direction of the friction member 12, can be substantially aligned with the rotational direction of the rotating body. As indicated by a broken line in FIG. 2, the friction member 12 may be curved so as to form irregularities in the first direction D1. Thereby, the friction member 12 comes to follow the rotation direction of a rotary body further.

  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 so as to go from the friction surface 12A toward the support portion 16 of the back plate 14. The first tapered surface 12B extends from the edge opposite to the connecting portion 18 in the second direction D2 on the friction surface 12A. The second tapered surface 12C extends from the end edge on the connecting portion 18 side in the second direction D2 on the friction surface 12A.

As described above, the friction member 12 includes an intermetallic compound produced from cobalt and titanium. The friction member 12 is made of Co ₃ Ti, Co ₂ Ti— (C 36), Co ₂ Ti— (C 15), Co ₂ Ti (c), Co ₂ Ti (h) as an intermetallic compound generated 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 generating 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 generating 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 production of the intermetallic compound to the total material is the second volume ratio of titanium used for the production of the intermetallic compound to the second volume ratio. 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 generated.

Preferably, in the material for forming the friction member 12, the first mass ratio of cobalt used for the production of 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 generating 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 with respect to the total material of cobalt used for generating the intermetallic compound is the second mass ratio with respect to the total material of titanium used for generating the intermetallic compound. 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 generated.

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

  Preferably, the friction member 12 further includes an abrasive. The abrasive improves braking performance due to contact between the friction member 12 and the rotating body. Abrasives include mullite, zircon, and sericite. One or more of these materials are selected and used as an abrasive. In order to make the braking performance of the friction member 12 appropriate, the volume ratio of the abrasive in generating the friction member 12 is preferably 5% or more and 30% or less. Moreover, it is preferable that the mass ratio of the abrasive | polishing agent in the production | generation of the friction member 12 is 5% or more and 20% or less.

Preferably, the friction member 12 further includes a volume adjusting agent. The volume adjusting agent 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. An example of the volume adjusting agent is calcium fluoride (CaF ₂ ). In order to achieve both size reduction and braking performance of the friction member 12, the volume ratio of the volume adjusting agent in the generation of the friction member 12 is preferably 5% or more and 30% or less. Further, the mass ratio of the volume adjusting agent in the generation 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 includes 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. Ti-Co intermetallic compound containing two. The friction member 12 of the second example includes the additive material in the friction member 12 of the first example. Examples of the additive material include mullite, zircon, sericite, and calcium fluoride. Non-metallic particles can 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 metal material. The metal material includes cobalt powder and titanium powder. Preferably, the material includes an additive material. The additive material is, for example, at least one of the above-described mullite, zircon, sericite, and calcium fluoride. Co ₃ Ti, Co ₂ Ti— (C 36), Co ₂ Ti— (C 15), Co ₂ Ti (c), Co ₂ Ti (h), CoTi, CoTi _{2 are} produced by burning a workpiece containing cobalt powder and titanium powder. At least one of these is formed.

  Next, three examples of the connection structure of the friction member 12 in the back plate 14 are 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 in FIG.

  A first example will be described with reference to FIG. The friction member is diffusion bonded to the back plate 14. The term “diffusion bonding” means that “a metal element derived from one of two metal members diffuses into the inside of the other metal member to form a boundary structure, or a metal derived from two metal members. A boundary structure is formed by mutual diffusion of the elements, and the two metal members are directly (that is, not via a connecting member such as an adhesive and solder, which are different from the two metal members) by the boundary structure. Inorganic and chemically linked ".

  A second example will be described with reference to FIGS. 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 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 engagement portion 12E of the friction member 12 is press-fitted into the through hole 14A of the back plate 14, or the engagement portion 12E of the friction member 12 is crushed in a state of 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. 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 diffusion bonded to the bonding plate 20. The back plate 14 has a through hole 14B. The joining plate 20 and the back plate 14 are joined together by the engaging portion 20A formed when a part of the joining plate 20 flows into the through hole 14B of the back plate 14 by softening or melting.

With reference to FIG. 4, the manufacturing method of the brake pad 10a of the above-mentioned 1st example is demonstrated.
First, in the first step, a workpiece is formed from a material containing at least cobalt powder and titanium powder. The workpiece is obtained by pressure molding the material. The material is in a powder form and becomes the friction member 12 containing an intermetallic compound in the next step. The material may include the additive materials described above in addition to the cobalt powder and the titanium powder.

  Next, in the second step, combustion synthesis that generates an intermetallic compound in the friction member 12 is induced by heating the workpiece without bringing the workpiece and the back plate 14 into contact with each other. Thus, 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 opposite to the friction surface 12A is in contact with the back plate. The brake pad 10a is manufactured by heating and pressurizing this laminated body. The heating and pressurizing conditions depend on the materials of the friction member 12 and the back plate 14, so long as the pressure and temperature are sufficient to connect the friction member 12 and the back plate 14 at least partially and chemically. It can be appropriately adjusted according to the composition of the intermetallic compound of the friction member 12 and the material of the back plate 14.

  There is a boundary structure at the boundary between the friction member 12 and the back plate 14. An element (cobalt, titanium, etc.) derived from the friction member 12 and an element (eg, titanium, aluminum, etc.) derived from the back plate 14 coexist in the vicinity of the boundary surface between the friction member 12 and the back plate 14. An element derived from one of the friction member 12 and the back plate 14 (for example, the friction member 12) diffuses into the other of the friction member 12 and the other of the back plate (for example, the back plate), thereby forming a boundary structure. A boundary tissue 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 at least partially inorganically and chemically connected by diffusion bonding.

With reference to FIG. 5 and FIG. 6, the manufacturing method of the brake pad 10b of the above-mentioned 2nd example is demonstrated.
First, in the first step, similarly to the first example, a workpiece WK is formed from a material containing at least cobalt powder and titanium powder. The workpiece WK is obtained by pressure molding a material. At the time of pressure molding, the work WK is provided with an engaging portion.

  In the second step, the work WK is heated without contacting the work WK and the back plate 14, thereby inducing combustion synthesis that generates an intermetallic compound in the friction member 12. Thus, 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 Form. And the part which has come out of 14 A of through-holes 14A among the engaging parts 12E of the friction member 12 is crushed, and the engaging part 12E and the backplate 14 are engaged. Further, preferably, diffusion bonding may be formed at the boundary portion between the friction member 12 and the back plate 14 by heat-treating the workpiece WK in which the friction member 12 and the back plate 14 are engaged.

With reference to FIG. 7 and FIG. 8, the manufacturing method of the brake pad 10c of the above-mentioned 3rd example is demonstrated.
In the first step, similarly to the first example, the workpiece WK is formed from a material containing at least cobalt powder and titanium powder. The workpiece WK is obtained by pressure molding a material.
In the second step, the workpiece WK, the joining plate 20, and the back plate 14 are arranged in a three-layered structure. Here, the workpiece WK, the bonding plate 20 and the back plate 14 are arranged so that the bonding plate 20 contacts the workpiece 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 workpiece WK. The workpiece WK is heated so as to generate an intermetallic compound 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 a thermal stimulus from the outside to the work WK so that a combustion reaction that is an exothermic reaction is induced locally on the work WK. Specifically, the combustion reaction is started by irradiating a laser beam locally on the workpiece WK and locally heating the workpiece WK. For example, a combustion reaction is induced at one end of the workpiece WK by external thermal stimulation applied to one end (the upper surface on the opposite side of the joining plate). The combustion reaction proceeds in a chained manner from one end of the workpiece WK to the other end (for example, the lower surface in contact with the joining plate). Combustion synthesis is completed in a very short time, does not require continuous external heating, and requires a very small amount of external heating energy supply. Therefore, the manufacturing cost of the friction member 12 can be significantly reduced.

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

  In this way, by applying an external thermal stimulus to one end (the upper surface on the opposite side of the joining plate) of the workpiece WK, the friction member 12 is generated, the friction member 12 is chemically connected to the joining plate, and the joining plate. A sequence including a mechanical connection between 20 and the back plate 14 proceeds in a chain or automatically. This sequence is automatically terminated upon completion of the combustion reaction. In this way, the brake pad 10c is manufactured. As described above, the combustion synthesis is completed in a very 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 brake pad 10c is significantly reduced.

<Example>
Hereinafter, the Example of the friction member 12 is demonstrated compared with a comparative example.
Tables 1 and 2 show the compositions of Examples 1 to 6 and Comparative Examples in terms of materials. The value shown in the composition of Table 1 is the volume ratio of each material when forming the friction member 12 according to Examples 1 to 6 and the comparative example. The value shown in the composition of Table 2 is the mass ratio of each material for the same Example and Comparative Example as in Table 1. Each of the friction members 12 of Examples 1 to 6 and the friction member of Comparative Example is obtained by firing a workpiece in which materials are mixed at a temperature of 870 ° C.

Apart from Examples 1-6, a powder sintered body of cobalt 76% titanium 24% was formed by the volume ratio of the materials. The firing temperature when forming the powder sintered body was 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 wear properties and the dynamic friction coefficient of the friction member are improved by the presence of an intermetallic compound of titanium and cobalt (for example, Co ₃ Ti).

The 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 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 volume ratio.
The third to sixth embodiments have the following configuration as compared to the first embodiment. In the order of Example 3 to Example 6, the volume ratio of the combined amount of graphite (natural, crystalline) and graphite (manufactured) is increased with respect to the total volume. On the contrary, cobalt and The volume ratio of the amount combined with titanium decreases in order. The volume ratio of cobalt and titanium is equal to the volume ratio of cobalt and titanium in Example 1. In Examples 1-6 and the comparative example, the volume ratio of mullite, zircon, and sericite is equal.

With reference to FIGS. 9-12, the effect of Examples 1-6 is shown. Examples 1 to 6 and the comparative example were compared in terms of wear amount and dynamic friction coefficient.
FIG. 9 is a graph showing the amount of wear for the comparative example (no heat radiating portion) and Examples 1 and 2.
FIG. 10 is a graph showing the time change of the dynamic friction coefficient for the comparative example (no heat radiating portion) and Examples 1 and 2.
FIG. 11 is a graph showing the amount of wear for a comparative example (with a heat radiating portion) and Examples 1 and 3 to 6.
FIG. 12 is a graph showing the change over time of the dynamic friction coefficient for the comparative example (with a heat radiating portion) and Examples 1 and 3 to 6.
In addition, the comparative example of FIG. 11 and FIG. 12 has a heat radiating part. Except for the comparative examples of FIG. 11 and FIG.

The amount of wear and the dynamic friction coefficient were measured under the following conditions. The friction area of the friction member 12 of the example and the reference example is 822.4 mm ² . Shimano (SMRT81S) was used as the rotating body. The rotational 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 performed for 30 minutes. According to this condition, the load is higher than that in 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 wear amount of the friction member 12 of Examples 1 to 6 was smaller than the wear amount of the friction member of the comparative example.
When Example 1 and Example 2 are compared, Example 1 has a smaller amount of wear than Example 2. From this, it can be seen that in the material, the volume ratio of cobalt is preferably larger than the volume ratio of titanium.

  The dynamic friction coefficients of the friction members 12 of Examples 1 to 6 are less reduced over time than the comparative examples. As can be seen from a comparison of Examples 1 to 6, as the graphite content increases, the dynamic friction coefficient decreases with time.

(Modification)
The description related to the above embodiment is an example of a form that the friction member and the brake pad according to the present invention can take, and is not intended to limit the form. The friction member and the brake pad according to the present invention can take a form in which, for example, the modifications of the above-described embodiment described below and at least two modifications not inconsistent with each other are combined. In the following modified examples, the same reference numerals as those in the embodiment are given to portions common to the embodiment, and the description thereof is 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 according to 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 dissipation portion 38 having a heat dissipation structure.

  The support part 36 and the heat radiating part 38 are provided in 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 a brake caliper of a manpowered vehicle. The friction member 32 is joined to the first surface 40 </ b> A at the support portion 36 of the main body 40. The heat radiating part 38 is provided on the second surface 40 </ b> B in 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 in the main body 40 so as not to face the friction member 32 via the main body 40. The heat radiating part 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 portion 38 has a heat radiating structure. The heat dissipation structure includes fins 42. A plurality of fins 42 are provided on the second surface 40 </ b> B of the main body 40. Each of the plurality of fins 42 is provided so as to extend from the second surface 40B to 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 the present embodiment, the fins 42 are integrally formed with the main body 40. When the fins 42 are formed separately, for example, holes for inserting the fins 42 are provided in the main body 40, and the fins 42 may be fixed to the holes by a method such as press fitting or adhesion. The main body 40 is provided with a through hole 40 </ b> C for passing a 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. A gap is formed between the two friction surfaces constituting the friction surface 12A. In this case, the friction area is calculated by the sum of the areas of the two friction surfaces. 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 man-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 bikes, cargo bikes, recumbent cars, and kick skaters.

L1 ... first dimension, L2 ... second dimension, L3 ... third dimension, 10 ... brake pad, 10a ... brake pad, 10b ... brake pad, 10c ... brake pad, 12 ... friction member, 12A ... friction surface, 14 ... Back plate, 16 ... support portion, 30 ... brake pad, 22 ... friction member, 24 ... intermetallic compound, 34 ... back plate, 36 ... support portion, 38 ... heat dissipation portion, 42 ... fin.

Claims (24)

Having a friction surface configured to contact the rotating body;
A friction member containing an intermetallic compound produced from cobalt and titanium. The intermetallic compound includes Co ₃ Ti.
The friction member according to claim 1. The friction member according to claim 1 or 2, wherein a first dimension of the friction surface in a first direction parallel to the friction surface is 15 mm or more and 30 mm or less. The friction member according to claim 3, wherein a second dimension of the friction surface in a second direction parallel to the friction surface and perpendicular to the first direction is 10 mm or more and 20 mm or less. The friction member according to claim 4, wherein the second dimension is smaller than the first dimension. The friction member according to any one of claims 3 to 5, wherein the friction member is curved so as to form irregularities in the first direction. The friction member according to any one of claims 1 to 6, wherein a third dimension of the friction member in a third direction perpendicular to the friction surface is 1.5 mm or more and 5 mm or less. The friction member according to any one of claims 1 to 7, wherein a first volume ratio of cobalt to all materials used for generating the intermetallic compound is set to 5% or more and 40% or less. The friction member according to any one of claims 1 to 8, wherein a second volume ratio of titanium used for generation of the intermetallic compound with respect to all materials is set to 5% or more and 40% or less. The first volume ratio of cobalt used for the production of the intermetallic compound is different from the second volume ratio of titanium used for the production of the intermetallic compound.
The friction member according to claim 9. The friction member according to claim 10, wherein the first volume ratio is larger than the second volume ratio. The friction member according to any one of claims 1 to 11, wherein a first mass ratio with respect to all materials of cobalt used for generating the intermetallic compound is set to 30% or more and 70% or less. The friction member according to any one of claims 1 to 12, wherein a second mass ratio with respect to all materials of titanium used for generation of the intermetallic compound is set to 5% or more and 20% or less. The first mass ratio with respect to the total material of cobalt used for generating the intermetallic compound is different from the second mass ratio with respect to the total material of titanium used for generating the intermetallic compound.
The friction member according to claim 13. The friction member according to claim 14, wherein the first mass ratio is larger than the second mass ratio. The friction member according to claim 1, further comprising a friction modifier. The friction member according to claim 1, further comprising an abrasive. The friction member according to claim 1, further comprising a volume adjusting agent. The friction member according to any one of claims 1 to 18,
And a back plate for supporting the friction member. The brake pad according to claim 19, wherein the friction member is diffusion bonded to the back plate. The brake pad according to claim 19, wherein the friction member is mechanically joined to the back plate. The brake pad according to any one of claims 19 to 21, wherein the back plate is formed of any one of an iron alloy, titanium, a titanium alloy, and an aluminum alloy. The brake pad according to any one of claims 19 to 22, wherein the back plate includes a support portion that supports the friction member and a heat dissipation portion having a heat dissipation structure. The brake pad according to claim 23, wherein the heat dissipation structure includes a fin.