JP2005036939A - Brake pad - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake pad which less attacks a counterpart and offers excellent abrasion resistance. <P>SOLUTION: A brake pad 10 consists of a fiber base material, friction adjusting agent and binder material. When the weight of the brake pad 10 is set at 100 wt.%, steel fiber or stainless fiber is included as a fiber base material in a range of not less than 15 wt.% and not more than 50 wt.%. Metals other than steels such as copper or zinc are contained as a friction adjusting agent in a range of not less than 1 wt.% and not more than 10 wt.%. Iron oxide is included in a range of not less than 1 wt.% and not more than 10 wt.%. By so doing, while suppressing attack property to a rotor 20 which is a counterpart, abrasion resistance of the brake pad 10 can be enhanced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a brake pad applied to an automobile or the like.

  Generally, a brake pad includes a fiber base selected from organic fibers, inorganic fibers, metal fibers, and the like, a powder raw material composed of a friction modifier and a filler, and a binder composed of a binder resin such as a phenol resin. It is manufactured by mixing and thermoforming the mixed raw material composition.

  Such a brake pad is used, for example, in an automobile disc brake or the like, and exhibits a braking action by a frictional action between a mating member such as a rotor and the brake pad.

  As required characteristics of the brake pad, in addition to a high friction coefficient and excellent wear resistance, there is a demand for the wear and damage of the mating material to be small, that is, the mating attack is small.

  In order to increase the friction coefficient of the brake pad and increase the wear resistance, it is common practice to add iron-based fibers such as steel fibers and stainless steel fibers as the fiber base material constituting the brake pads. Yes.

  However, steel fibers and stainless fibers are highly aggressive against the mating material and tend to damage the mating material. One of the reasons for this is that, in addition to the hard material of steel fiber and stainless steel fiber, the counterpart material such as the rotor is generally made of an iron-based metal like the brake pad.

  If friction occurs between the brake pad, which is an iron-based metal, and the rotor, which is the same iron-based metal, the friction between the brake pad and the iron constituting the rotor causes seizure between the brake pad surface and the rotor surface. It becomes prone to rough.

  This is considered to be because the brake pad and the iron constituting the rotor are melted by the heat of friction, and the brake pad and rotor portions softened thereby are broken into large chunks. In other words, it is considered that simple mechanical wear is eliminated.

  In brake pads to which steel fibers such as steel fibers and stainless fibers are added in this way, the surface of the brake pads and the surface of the rotor tend to be rough, so vibration is likely to occur during braking of the brake, etc. A problem occurs.

  In view of such circumstances, conventionally, non-steel brake pads that do not use steel have been proposed (see, for example, Patent Document 1). This uses a non-steel metal fiber such as copper or an aramid fiber as a fiber base material. In particular, the brake pad described in Patent Document 1 is intended to improve the wear resistance of the brake pad by further including graphite having a specific composition.

Conventionally, a brake pad in which the amount of steel fiber is reduced from a general amount has been proposed. As such, for example, a brake pad has been proposed in which steel fibers having an average fiber diameter of 80 μm or less and a thin fiber diameter are contained in a small range of 1 wt% or more and 15 wt% or less (patent) Reference 2).
Japanese Patent Publication No. 7-37604 JP 2002-155237 A

  However, the non-steel brake pad as described in Patent Document 1 has low opponent attack because it does not use steel fiber, that is, the opponent attack is excellent, but the following problems occur. .

  That is, the non-steel brake pads are less likely to attack the opponent, so the brake pads themselves are more likely to be worn away. As a result, the brake pad wear powder is transferred to the opponent material. And the friction coefficient falls by transfer of this wear powder to the other party material, or the malfunction that abnormal noise generate | occur | produces arises.

  Moreover, in the brake pad which reduced the quantity of the steel fiber as described in the said patent document 2, although a partner aggression property is reduced by the weight reduction of a steel fiber, the abrasion resistance of a brake pad becomes inadequate.

  SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a brake pad that is less attacked by a counterpart material and has good wear resistance.

  In order to achieve the above object, the present inventor maintained the amount of these iron-based fibers at the same level as that of a conventional general steel-based brake pad without reducing the amount of iron-based fibers such as steel fibers or stainless steel fibers. As it was, we conducted an experimental study, considering the suppression of the opponent's aggression.

  As a result, it was experimentally found that it is effective to add powder or fiber of metal other than steel and iron oxide in order to suppress the opponent attack on the steel brake pad.

  In steel brake pads, the addition of metals other than steel and iron oxide is not clear as a mechanism that can suppress (reduce) the opponent attack of the brake pads, but the following may be considered. .

  As described above, conventionally, a steel brake pad including steel fibers frictions with a counterpart material such as a rotor that is also made of a ferrous metal, and at this time, iron and a counterpart material constituting the brake pad constitute a counterpart material. It is thought that the parts of the brake pad and the rotor, which are melted by the heat of friction and softened by the friction, are broken up into large chunks.

  Here, when a metal other than steel and iron oxide are added to the steel brake pad, the friction between the brake pad and the counterpart material is simply not the friction between the iron metals due to the presence of these additives. .

  Therefore, the reaction that the brake pad and the counterpart material are melted by the heat of friction is suppressed, and as a result, the friction between the brake pad and the counterpart material is limited to normal mechanical wear. And it is thought that the particle size of the abrasion powder of a brake pad at the time of braking of a brake becomes finer than before.

  Then, it is thought that the attack to the other material of a brake pad becomes small because this fine abrasion powder adheres to the other material as a protective film (coating). At this time, it is considered that the metal other than steel is oxidized by the heat at the time of friction and becomes a metal oxide.

  Therefore, the component of the coating that adheres to the counterpart material is considered to be an oxide of a metal other than iron oxide or the steel, and therefore, the strength of the coating is large and the coating is difficult to peel from the counterpart material. Conceivable. And it is thought that a fall of a friction coefficient and generation | occurrence | production of abnormal noise are suppressed by protecting a counterpart material with such a strong film.

  This is the presumed mechanism for the ability to suppress (reduce) the opponent attack of the brake pad by adding a metal other than steel and iron oxide in the steel brake pad.

  Then, in view of the balance of the characteristics of the brake pad, further experimental studies were conducted in order to determine an appropriate composition for each component of steel fiber or stainless fiber, metal other than steel, and iron oxide. The present invention has been created based on the results and findings obtained from such studies.

  That is, in the invention according to claim 1, in the brake pad (10) comprising the fiber base material, the friction modifier, and the binder, the fiber base material has a weight of 100% by weight. Steel fiber or stainless fiber is included in the range of more than 15% by weight and 50% by weight or less, and the friction modifier includes metals other than steel in the range of 1% by weight to 10% by weight. In addition, iron oxide is contained in the range of 1 wt% to 10 wt%.

  According to this, it is possible to provide a brake pad (10) having less wear on the mating member (20) and good wear resistance.

  Here, if the amount of steel fiber or stainless steel fiber is 15% by weight or less, the steel pad or stainless steel fiber is too small and the brake pad skeleton is not sufficiently formed. The property becomes insufficient.

  Also, if the amount of steel fiber or stainless steel fiber exceeds 50% by weight, there are too many steel fibers or stainless steel fibers, and even if metals other than steel or iron oxide are added, it is difficult to suppress the opponent attack Become.

  On the other hand, if the amount of metal other than steel and iron oxide is less than 1% by weight, the effect of suppressing opponent attack by the metal other than steel and iron oxide becomes insufficient.

  Moreover, when the amount of metal other than steel and iron oxide exceeds 10% by weight, the phenomenon of transfer of a coating made of metal other than steel or iron oxide to the counterpart material as shown in the above estimation mechanism becomes excessively remarkable. In fact, the friction coefficient is reduced and abnormal noise is generated.

  In the brake pad (10) of the present invention, the above includes steel fiber or stainless steel as a fiber base in a range of more than 15% by weight and 50% by weight or less, and a metal other than steel as a friction modifier and oxidation This is the basis for including iron in the range of 1 to 10% by weight.

  Further, the invention according to claim 2 is characterized in that the metal other than the steel is softer than steel.

  In the steel brake pad (10), in order to suppress opponent attack, that is, to reduce opponent attack, it is preferable to employ a metal other than steel that is softer than steel.

  As the invention described in claim 3, as the metal softer than the steel described above, one or more selected from copper (Cu), zinc (Zn), aluminum (Al), bronze and brass are employed. can do.

  In addition, the code | symbol in the bracket | parenthesis of each said means is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments shown in the drawings will be described below.

  FIG. 1 is a diagram showing a schematic configuration of a brake pad 10 according to an embodiment of the present invention, and schematically shows a positional relationship between the brake pad 10 and a rotating rotor 20. Moreover, in FIG. 1, (b) is AA schematic sectional drawing of (a).

  As shown by the arrow Y1 in FIG. 1A, when the rotor 20 as the counterpart material is rotating, the brake pad 10 is in the direction of the arrow Y2 in FIG. Pushed in the direction. In this state, the rotor 20 slides, whereby a braking action is exhibited. The rotor 20 is made of an iron-based metal.

  The brake pad 10 of this embodiment is a bond made of a fiber base material selected from inorganic fibers, organic fibers, metal fibers, etc., a powder raw material consisting of a friction modifier and a filler, a binder resin such as a phenol resin, and the like. A material is mixed by a dry method, and a raw material composition obtained by this mixing is thermoformed.

  Here, in the brake pad 10 of the present embodiment, at least steel fibers or stainless fibers are used as the fiber base material. When the weight of the brake pad is 100% by weight, the steel fiber or the stainless fiber is assumed to be included in the range of more than 15% by weight and 50% by weight or less.

  The steel fiber is a fiber made of only steel, that is, iron, and the stainless steel fiber is a stainless steel, that is, a fiber made of Fe—Cr alloy to which a small amount of Cr (generally 12% or more) is added.

  Further, the sizes of the steel fibers and the stainless fibers are not particularly limited. For example, those having an average fiber diameter of 100 μm and an average fiber length of 3 mm can be used.

  Moreover, in the brake pad 10 of this embodiment, including steel fiber or stainless steel fiber may include only one of steel fiber and stainless steel fiber, or both steel fiber and stainless steel fiber. It means that it may contain.

  When only one of the former steel fibers and stainless fibers is included, for example, when only steel fibers are included, the weight of the steel fibers is set in the range of more than 15% by weight and not more than 50% by weight. When both the latter steel fiber and stainless steel fiber are included, the total weight of the steel fiber and the stainless steel fiber is set in the range of more than 15% by weight and 50% by weight or less.

  Moreover, in this embodiment, you may use the fiber base material employ | adopted for a general brake pad other than these steel fiber or stainless steel fiber with said steel fiber or stainless steel fiber as needed. Usually, in addition to steel fibers or stainless fibers, organic fibers and inorganic fibers are included.

  For example, in a fiber base material, an aramid fiber, a carbon fiber, or the like can be used as the organic fiber, and a glass fiber, a potassium titanate fiber, a ceramic fiber, a calcium silicate fiber, or the like can be used as the inorganic fiber. Can do.

  As the friction modifier, metal powder, lubricant, and inorganic oxide powder are blended. In the present embodiment, at least a metal other than steel and iron oxide are used as the friction modifier.

  And about the compounding ratio of metals other than steel and iron oxide, when the weight of a brake pad is 100 wt%, metals other than the steel are included in a range of 1 wt% to 10 wt%, It is assumed that iron oxide is contained in the range of 1 wt% to 10 wt%.

  Here, the metal other than steel may be powder or fiber, and for example, a material softer than steel can be adopted. A metal softer than steel means that the metal has a Mohs hardness (Morse Scale) that is smaller than that of steel. That is, the Mohs hardness of steel (Fe) is 4.5, and a metal having a Mohs hardness of less than 4.5 is employed.

  Specifically, metals that are softer than steel include copper (Cu) with a Mohs hardness of 3.0, zinc (Zn) with a Mohs hardness of 2.5, and aluminum with a Mohs hardness of 2.9 (Al ), Bronze having a Mohs hardness of 3.5, brass having a Mohs hardness of 3.5, and the like. Note that bronze is an alloy of copper and tin (Cu—Sn alloy), and brass is an alloy of copper and zinc (Cu—Zn alloy).

  Further, when using a metal softer than steel as the powder, the size (average particle size) of each powder is not limited, but for example, aluminum powder has a particle size of about 1 mm, copper powder has a particle size of about 200 μm, The zinc powder can have a particle size of about 500 μm, the bronze powder can have a particle size of about 500 μm, and the brass powder can have a particle size of about 200 μm.

  And as a metal softer than these steels, the 1 type selected from copper, zinc, aluminum, bronze, brass, etc. mentioned above may be sufficient, and it is good also as multiple types selected from these.

  When one kind of metal softer than steel is used, the one kind of metal is set in the range of 1 wt% to 10 wt%. Further, when there are a plurality of kinds of metals softer than steel, the total weight of the plurality of kinds of metals is set in the range of 1 wt% or more and 10 wt% or less.

As iron oxide, triiron tetroxide (Fe ₃ O ₄ ) or diiron trioxide (Fe ₂ O ₃ ) can be used.

  Furthermore, in the present embodiment, if necessary, a metal other than steel and iron oxide other than the above-described steel, and a friction modifier used for a general brake pad in addition to the metal other than steel and iron oxide are used. Good.

  For example, graphite (graphite), antimony trisulfide, molybdenum disulfide, zinc disulfide, etc. can be adopted as lubricants, and inorganic oxide powders such as silica, alumina, silicon carbide, zirconium oxide, zirconium silicate, etc. Can be adopted.

  Further, as the filler, an inorganic material and an organic material are usually used in combination. Barium sulfate, calcium carbonate, calcium hydroxide, mica, kaolin, talc, etc. can be adopted as inorganic fillers, and cashew dust, rubber dust, etc. can be adopted as organic fillers. it can.

  Moreover, a general binder resin can be adopted as the binder. Specifically, urea resin, melamine resin, epoxy resin, urethane resin, polyimide resin, etc. or modified resins thereof can be employed as well as commonly used powdery phenol resins.

  The brake pad 10 of this embodiment is manufactured through a manufacturing process as shown in FIG. 2 using the raw material composition containing the above-described raw materials. FIG. 2 is a process diagram showing a method for manufacturing the brake pad 10 according to the present embodiment.

(Weighing process)
First, a fiber base material, a powder raw material composed of a friction modifier and a filler, and a binder are weighed at a predetermined composition ratio.

(Mixing process)
Each measured raw material component is put into a mixer and mixed dry. For example, a general mixer such as an Eirich mixer can be used as the mixer. The raw material composition which consists of a fiber base material, the powder raw material which consists of a friction modifier and a filler, and a binder by the process so far is produced.

(Weighing process)
Next, this raw material composition is taken out from the mixer, and weighed to separate a predetermined amount.

  Subsequently, a predetermined amount of the raw material composition is put into a mold, and thereafter thermoforming is performed. Here, in order to make the separated raw material composition into a block body, a preliminary molding, that is, an extrusion molding may be performed using another mold before performing the main molding.

(Main molding process)
For example, in the mold heated to 160 ° C., the above-described separated raw material composition or the raw material composition used in the extrusion molding is put and pressed to produce a molded body.

(Heat treatment process)
Thereafter, the molded body produced by the main molding process is cured by, for example, heat treatment at 200 ° C. or higher. Thus, the brake pad 10 is completed.

  By the way, in this embodiment, when the weight of the brake pad 10 is 100% by weight in the brake pad 10 made of the fiber base material, the friction modifier and the binder, the fiber base material is 15% by weight of steel fiber or stainless steel fiber. More than 50% by weight, and as a friction modifier, metals other than steel are included in the range of 1% by weight to 10% by weight, and iron oxide is 1% by weight to 10% by weight. The main feature is that it is included in the range of% or less.

  This feature is achieved by reducing the amount of ferrous fibers such as steel fibers or stainless fibers, while maintaining the same level as that of conventional general steel brake pads, while maintaining the same amount of powder or fibers of metal other than steel. The attack of the opponent is suppressed by adding iron oxide.

  In this embodiment, it has been experimentally confirmed that adding a powder or fiber of metal other than steel or fiber and iron oxide to the steel brake pad can suppress the opponent aggression property. An estimation mechanism as shown in Fig. 2 is conceivable.

  As described above, conventionally, a steel brake pad including steel fibers rubs against a counterpart material such as a rotor, which is also made of a ferrous metal. At this time, the steel and the counterpart material constituting the brake pad constitute the counterpart material. It is thought that the parts of the brake pad and the rotor, which are melted by the heat of friction and softened by the friction, are broken up into large chunks.

  Here, as in the present embodiment, when a metal other than steel and iron oxide are added to the steel brake pad 10, the addition of these additives causes the brake pad 10 and the rotor 20 that is the counterpart material to intervene. Friction is simply not friction between ferrous metals.

  Therefore, the reaction that the brake pad 10 and the rotor (partner material) 20 are melted by the heat of friction is suppressed, and as a result, the friction between the brake pad 10 and the rotor 20 is limited to normal mechanical wear. And it is thought that the particle size of the abrasion powder of the brake pad 10 at the time of braking of a brake becomes finer than before.

  Then, it is thought that the attack to the rotor 20 of the brake pad 10 becomes small because this fine abrasion powder adheres to the surface of the rotor 20 as a protective film (coating). At this time, it is considered that the metal other than steel is oxidized by the heat at the time of friction and becomes a metal oxide.

  Therefore, the component of the coating that adheres to the rotor 20 is considered to be an oxide of a metal other than iron oxide or the steel. Therefore, the strength of the coating is strong, and the coating is difficult to peel from the rotor 20. Conceivable. And it is thought that the reduction | decrease of a friction coefficient and generation | occurrence | production of abnormal noise are suppressed by protecting the rotor 20 with such a high intensity | strength film.

  In addition, in the above feature points, the weight ratios defined for each component of steel fiber or stainless fiber, metal other than steel, and iron oxide are experimentally determined in consideration of the characteristic balance of the brake pad 10. is there.

  If the amount of steel fiber or stainless steel fiber is 15% by weight or less, there is too little steel fiber or stainless steel fiber, and the brake pad skeleton is not sufficiently formed. It will be enough.

  Also, if the amount of steel fiber or stainless steel fiber exceeds 50% by weight, there are too many steel fibers or stainless steel fibers, and even if metals other than steel or iron oxide are added, it is difficult to suppress the opponent attack Become.

  On the other hand, if the amount of metal other than steel and iron oxide is less than 1% by weight, the effect of suppressing opponent attack by the metal other than steel and iron oxide becomes insufficient.

  Further, when the amount of metal other than steel and iron oxide exceeds 10% by weight, it is considered that the transfer of the coating made of metal other than steel or iron oxide to the rotor 20 as shown in the above estimation mechanism becomes excessive. In fact, the friction coefficient is reduced and noise is generated.

  Here, the amount of metal other than steel and the amount of iron oxide are preferably in the range of 2 wt% to 5 wt% in order to make the characteristics of the brake pad 10 more balanced.

  As described above, according to the present embodiment, while utilizing the features of the steel fiber in the steel brake pad, by adopting a unique configuration in which a metal other than steel and iron oxide are contained in a predetermined ratio as a friction modifier, It is possible to provide a brake pad with less wear on the mating material and good wear resistance.

  Hereinafter, examples of the present embodiment will be shown and described more specifically.

  Examples 1 to 4 and Comparative Examples 1 and 2 are shown below. Table 1 shows the raw material components and amounts used in the brake pads of these examples. The present invention is not limited to these examples.

この表１では、繊維基材としては、アラミド繊維、スチール繊維、ステンレス繊維を用い、摩擦調整剤としては銅粉末、亜鉛粉末、青銅粉末といったスチール以外の金属の粉末と酸化鉄と黒鉛とを用いている。

In Table 1, aramid fiber, steel fiber, and stainless steel fiber are used as the fiber base material, and a metal powder other than steel, such as copper powder, zinc powder, and bronze powder, and iron oxide and graphite are used as the friction modifier. ing.

Here, as the steel fiber and the stainless fiber, those having an average fiber diameter of 100 μm and an average fiber length of 3 mm were used. As the metal powder other than steel, copper powder having an average particle size of 200 μm, zinc powder having an average particle size of 500 μm, and bronze powder having an average particle size of 200 μm were used. Further, triiron tetroxide (Fe ₃ O ₄ ) was used as the iron oxide.

  In Table 1 above, cashew dust, calcium hydroxide, mica, and barium sulfate were used as fillers, and powdered phenol resin was used as a binder as a binder. Here, in Table 1, the raw material composition, that is, the amount of each raw material component is wt% (wt%).

(Example 1)
5% by weight aramid fiber, 16% by weight steel fiber, 1% by weight copper powder, 1% by weight iron oxide, 5% by weight graphite, 5% by weight cashew dust, 2% by weight calcium hydroxide, 5% by weight mica, 45% barium sulfate The mixture by weight was uniformly mixed by dry method for 5 minutes using an Eirich mixer to obtain a raw material composition.

This raw material composition was put into a mold heated to 160 ° C. so as to have a predetermined shape, and pressed for 10 minutes under the condition of 200 kg / cm ² to produce a molded body. Thereafter, this molded body was cured at 230 ° C. for 3 hours to produce a brake pad of this example.

  In this Example 1 and the following Examples 2, 3, 4 and Comparative Examples 1 and 2, the composition of each component in the completed brake pad is substantially the same as the composition shown in Table 1 above.

(Example 2)
5% by weight aramid fiber, 50% by weight steel fiber, 5% by weight copper powder, 5% by weight zinc powder, 5% by weight iron oxide, 5% by weight graphite, 5% by weight cashew dust, 2% by weight calcium hydroxide, 5 mica A mixture of 5% by weight and 3% by weight of barium sulfate was uniformly mixed by a dry method for 5 minutes using an Eirich mixer to obtain a raw material composition.

This raw material composition was put into a mold heated to 160 ° C. so as to have a predetermined shape, and pressed for 10 minutes under the condition of 200 kg / cm ² to produce a molded body. Thereafter, this molded body was cured at 230 ° C. for 3 hours to produce a brake pad of this example. In this example, the amount of metal other than steel is 10% by weight as a total of 5% by weight of copper powder and 5% by weight of zinc powder.

(Example 3)
5% by weight aramid fiber, 16% by weight stainless steel, 10% by weight bronze powder, 10% by weight iron oxide, 5% by weight graphite, 5% by weight cashew dust, 2% by weight calcium hydroxide, 5% by weight mica, 32 barium sulfate The mixture by weight was uniformly mixed by dry method for 5 minutes using an Eirich mixer to obtain a raw material composition.

This raw material composition was put into a mold heated to 160 ° C. so as to have a predetermined shape, and pressed for 10 minutes under the condition of 200 kg / cm ² to produce a molded body. Thereafter, this molded body was cured at 230 ° C. for 3 hours to produce a brake pad of this example.

(Example 4)
5% by weight aramid fiber, 30% by weight stainless steel, 3% by weight copper powder, 3% by weight zinc powder, 5% by weight iron oxide, 5% by weight graphite, 5% by weight cashew dust, 2% by weight calcium hydroxide, 5 mica A mixture of 5% by weight and 27% by weight of barium sulfate was uniformly mixed by a dry method for 5 minutes using an Eirich mixer to obtain a raw material composition.

This raw material composition was put into a mold heated to 160 ° C. so as to have a predetermined shape, and pressed for 10 minutes under the condition of 200 kg / cm ² to produce a molded body. Thereafter, this molded body was cured at 230 ° C. for 3 hours to produce a brake pad of this example. In this example, the amount of metal other than steel is 6% by weight as a total of 3% by weight of copper powder and 3% by weight of zinc powder.

(Comparative Example 1)
5% by weight aramid fiber, 30% by weight steel fiber, 0.5% by weight zinc powder, 0.5% by weight iron oxide, 5% by weight graphite, 5% by weight cashew dust, 2% by weight calcium hydroxide, 5% by weight mica Then, a mixture of 47% by weight of barium sulfate was uniformly mixed by a dry method for 5 minutes using an Eirich mixer to obtain a raw material composition.

This raw material composition was put into a mold heated to 160 ° C. so as to have a predetermined shape, and pressed for 10 minutes under the condition of 200 kg / cm ² to produce a molded body. Thereafter, this molded body was cured at 230 ° C. for 3 hours to produce a brake pad of this example.

  In addition, in Comparative Example 1, the amount of metal other than steel is 0.5% by weight of zinc powder, and the amount of iron oxide is 0.5% by weight, both from the weight range defined in the above embodiment. It is also a small amount.

(Comparative Example 2)
5% by weight aramid fiber, 30% by weight steel fiber, 10% by weight copper powder, 5% by weight zinc powder, 15% by weight iron oxide, 5% by weight graphite, 5% by weight cashew dust, 2% by weight calcium hydroxide, 5 mica A mixture of 5% by weight and 8% by weight of barium sulfate was uniformly mixed by a dry method for 5 minutes using an Eirich mixer to obtain a raw material composition.

This raw material composition was put into a mold heated to 160 ° C. so as to have a predetermined shape, and pressed for 10 minutes under the condition of 200 kg / cm ² to produce a molded body. Thereafter, this molded body was cured at 230 ° C. for 3 hours to produce a brake pad of this example.

  In this example, the amount of metal other than steel is 15% by weight as a total of 10% by weight of copper powder and 5% by weight of zinc powder, and the amount of iron oxide is 15% by weight. The amount is larger than the weight range defined in the embodiment.

(Brake pad evaluation)
The brake pads of Examples 1 to 4 and Comparative Examples 1 and 2 were evaluated by examining the friction coefficient of the brake pad, the amount of rotor attack, the wear resistance of the brake pad, and the occurrence of abnormal noise. The results of evaluating the characteristics of the brake pads of Examples 1 to 4 and Comparative Examples 1 and 2 are shown in Table 2 below.

摩擦係数は、日本自動車規格（ＪＡＳＯ）による一般性能試験の平均摩擦係数を表しており、ブレーキパッドの効きの指標となるものである。

The coefficient of friction represents an average coefficient of friction in a general performance test according to the Japan Automobile Standard (JASO), and serves as an index of the effectiveness of a brake pad.

  The rotor attack amount indicates the wear amount of the rotor 20 when a drag test is performed for 24 hours under a pressure of 0.1 MPa, and its unit is μm. The smaller the value of the rotor attack amount, the less the opponent aggression and the more the attack is suppressed.

  Abrasion resistance indicates the amount of wear of a brake pad when braking at 1.5 MPa at 200 ° C. and 50 km / h is repeated 2000 times, and its unit is mm. The smaller the wear resistance value, the better the wear resistance of the brake pad.

  Abnormal noise is based on evaluation with an actual vehicle. “Good” in Table 2 above means that no abnormal noise is generated or that it does not cause any sensuality, and “deteriorated” means abnormal noise. Is a problem.

(Evaluation result of Example 1)
The coefficient of friction was 0.40, the rotor aggression was 3 μm, the wear resistance was 0.200 mm, and the abnormal noise generation state was good.

(Evaluation result of Example 2)
The friction coefficient was 0.40, the rotor aggression was 5 μm, the wear resistance was 0.150 mm, and the abnormal noise generation state was good.

(Evaluation result of Example 3)
The coefficient of friction was 0.40, the rotor aggression was 2 μm, the wear resistance was 0.190 mm, and the abnormal noise generation state was good.

(Evaluation result of Example 4)
The coefficient of friction was 0.40, the rotor aggression was 3 μm, the wear resistance was 0.160 mm, and the abnormal noise generation state was good.

(Evaluation result of Comparative Example 1)
The friction coefficient was 0.40, the rotor aggression was 15 μm, the wear resistance was 0.300 mm, and the abnormal noise generation state was good.

(Evaluation result of Comparative Example 2)
The coefficient of friction was 0.40, the rotor aggression was 3 μm, the wear resistance was 0.150 mm, and the abnormal sound generation state was in a deteriorated state.

  As can be seen from the results shown in Table 2, here, the brake pads of Examples 1 to 4 and Comparative Examples 1 and 2 show the same friction coefficient. That is, the friction coefficient, which is a basic characteristic of the brake pad, is made to be comparable between the examples, and the other characteristics of each example are compared.

  And in Examples 1-4, desired rotor attack property and abrasion resistance are obtained. On the other hand, in Comparative Example 1, the amount of addition of metals other than steel and iron oxide is small, so the rotor attack is deteriorated. In Comparative Example 2, the amount of addition of metals other than steel and iron oxide is too large. The abnormal noise worsened.

  If it says further about each comparative example 1 and 2, in comparative example 1, the abrasion resistance of a brake pad will also deteriorate. This is because the amount of added metal and iron oxide other than steel is small, so that friction between the iron constituting the brake pad and the iron constituting the rotor occurs substantially during braking, and both irons melt and become large. It is thought that this is a result of being broken up as a lump.

  Moreover, in comparative example 2, since there are too many addition amounts of metals other than steel and iron oxide, as a result of the transfer to the rotor 20 of the film which consists of metals other than steel or iron oxide too much, abnormal noise will deteriorate. Conceivable.

  Moreover, when comparing between Examples 1 to 4, the following can be said roughly. First, there is not much difference between the case where steel fiber is used as the fiber substrate and the case where stainless fiber is used.

  Moreover, when Example 1 and Example 3 are compared, the amount of steel fiber and stainless steel fiber is comparable, but the amount of metal other than steel and iron oxide is 1% by weight in Example 1, respectively. In Example 3, the amount is 10% by weight, more. However, in Example 1 and Example 3, there is no great difference in rotor attack and brake pad wear resistance, and good characteristics are shown.

  Further, compared to Example 1, in Examples 2 and 4, the amount of steel fibers or stainless fibers is large. Therefore, in order to suppress rotor attack by steel, Examples 2 and 4 are more preferable than Example 1. Compared to, the amount of metals other than steel and iron oxide is increased to ensure a more appropriate balance of properties. From the results shown in Table 1 and Table 2, the more desirable amounts of metals other than steel and iron oxide are about 2 wt% to 5 wt%.

  In any case, Examples 1 to 4 constitute brake pads having the characteristic points shown in the above embodiment, and in these Examples 1 to 4, there is little attack on the mating material and wear resistance. There are good brake pads provided.

  Further, when the amount of steel fiber or stainless steel fiber is 15% by weight or less, the wear resistance becomes insufficient, and when the amount of steel fiber or stainless steel fiber exceeds 50% by weight, the rotor attack property is deteriorated. That is confirmed experimentally.

  In addition, in the said Example, although powder was used as metals other than steel, when using a fiber, it has confirmed that the same evaluation result is obtained. Moreover, the same evaluation result as the said Example is obtained even if it uses ferric trioxide as iron oxide.

  In addition to the application as a brake pad for an automobile disc brake shown in FIG. 1, the present invention can of course be applied as a brake pad for a drum brake and other various brake pads.

It is a figure showing a schematic structure of a brake pad concerning an embodiment of the present invention. It is process drawing which shows the manufacturing method of the brake pad which concerns on the said embodiment.

Explanation of symbols

  10 ... Brake pads, 20 ... Rotor as counterpart material.

Claims (3)

In a brake pad comprising a fiber base material, a friction modifier and a binder,
When the weight of the brake pad is 100% by weight, the fiber base material includes steel fiber or stainless steel fiber in a range of more than 15% by weight and 50% by weight or less,
A metal other than steel is contained in the range of 1 wt% to 10 wt% as the friction modifier, and iron oxide is contained in the range of 1 wt% to 10 wt%. Brake pads. The brake pad according to claim 1, wherein the metal other than steel is softer than steel. The brake pad according to claim 2, wherein the metal other than steel is at least one selected from copper, zinc, aluminum, bronze and brass.

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