CN112996878A - Sintered friction material and method for producing sintered friction material - Google Patents

Abstract

Translated fromChinese

本发明涉及一种烧结摩擦材料，其中，铜成分的含量为0.5质量％以下，含有铜以外的金属材料和钛酸盐作为基体，所述铜以外的金属材料的含量为10.0～34.0体积％。本发明的烧结摩擦材料对环境友好，即使在高速区域也具有足够的摩擦性能。The present invention relates to a sintered friction material, wherein the content of a copper component is 0.5 mass % or less, a metal material other than copper and a titanate are contained as a matrix, and the content of the metal material other than copper is 10.0 to 34.0 volume %. The sintered friction material of the present invention is environmentally friendly and has sufficient friction performance even in a high-speed region.

Description

Sintered friction material and method for producing sintered friction material

Technical Field

The present invention relates to a sintered friction material and a method for producing a sintered friction material.

Background

In recent years, it has been pointed out that abrasion powder generated when a friction material containing a copper component brakes contains a copper component, and may cause pollution to rivers, lakes, oceans, and the like. Therefore, the use of friction materials containing copper components is more and more restricted, and a friction material having excellent friction action even when the content of copper components is small is desired.

For example, the present applicant has proposed a friction material containing a ceramic matrix and a carbon material in patent document 1.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 6061592

Disclosure of Invention

Technical problem to be solved by the invention

However, in the sintered friction material described in patent document 1, although a friction test was performed at an initial speed of 50km/h, evaluation in a high speed region of the speed or higher was not investigated.

The present invention has been made in view of the above-described conventional circumstances, and an object thereof is to provide a sintered friction material which has a copper content of a predetermined amount or less and which has sufficient friction performance in a high-speed region as an environmentally friendly friction material.

Means for solving the problems

As a result of intensive studies, the present inventors have found that the above problems can be solved by using a metal material other than copper and a titanate as a matrix of a sintered friction material, and have completed the present invention.

That is, the present invention relates to the following <1> - <6 >.

[ 1] A sintered friction material which contains a copper component in an amount of 0.5 mass% or less, contains a metal material other than copper in an amount of 10.0 to 34.0 vol% and a titanate as a matrix.

<2> the sintered friction material as stated in <1>, wherein the titanate contains at least 1 salt selected from the group consisting of alkali metal titanate, alkaline earth metal titanate and complex titanate.

<3> the sintered friction material as stated in <1> or <2>, wherein the titanate contains at least 1 salt selected from the group consisting of potassium titanate, sodium titanate, calcium titanate, potassium lithium titanate and potassium magnesium titanate.

The sintered friction material as described in any of < 4 > to <1> -3 >, wherein the metal material other than copper contains an iron-based material, and the content of the iron-based material is 8.0 to 32.0 vol%.

The sintered friction material as described in any of < 5 > to <1> -4 >, wherein the metal material other than copper further contains tungsten, and the content of tungsten is 1.0 to 15.0 vol%.

<6> a method for manufacturing a sintered friction material, comprising: a mixing step of mixing a raw material containing a metal material other than copper and a titanate; a molding step of molding the raw materials mixed in the mixing step; and a sintering step of sintering the molded body molded in the molding step at 900 to 1300 ℃, wherein the sintered friction material comprises a matrix composed of the metal material other than copper and the titanate, and the content of the metal material other than copper is 10.0 to 34.0 vol%.

Effects of the invention

According to the present invention, a sintered friction material which is environmentally friendly and has sufficient friction performance even in a high-speed region can be provided.

Detailed Description

The present invention will be described in detail below, but these are merely examples of preferred embodiments, and the present invention is not limited to these.

[ sintered Friction Material ]

The sintered friction material is characterized in that the content of copper component is 0.5 mass% or less, a metal material other than copper and titanate are contained as a matrix, and the content of the metal material other than copper is 10.0-34.0 vol%.

< matrix >

In the present invention, the "matrix" means a component constituting the main skeleton of the friction material.

(metallic materials other than copper)

The sintered friction material of the present invention contains a metal material other than copper (hereinafter, may be simply referred to as "metal material") as a base in an amount of 10.0 to 34.0 vol%.

If the content of the metal material in the sintered friction material of the present invention is less than 10.0 vol%, the adhesion force between the metal materials between the sintered friction material and the mating material of the sintered friction material is reduced, and there is a possibility that a sufficient adhesion friction force cannot be obtained. Therefore, if the content of the metal material is less than 10.0 vol%, the sintered friction material of the present invention may not be provided with a sufficient friction coefficient μ in a high-speed region.

The content of the metal material is preferably 12.5 vol% or more, and more preferably 14.0 vol% or more, from the viewpoint of improving the friction performance.

If the content of the metal material is more than 34.0 vol%, the amount of the metal material transferred to the material to be blended in the sintered friction material may increase. If the amount of migration of the metal material increases, the strength of the sintered friction material of the present invention decreases, and the wear resistance may decrease.

From the viewpoint of improving the wear resistance, the content of the metal material is preferably 32.0 vol% or less, and more preferably 30.0 vol% or less.

Examples of the metal material include: iron-based materials, tungsten, tin alloys, titanium, aluminum, silicon, zinc, and Fe — Al intermetallic compounds, and the like. These may be used alone or in combination of two or more.

Among these metal materials, iron-based materials, tungsten, and tin are preferable from the viewpoint of improving the friction performance of the sintered friction material.

When the metal material contains an iron-based material, the content of the iron-based material in the sintered friction material of the present invention is preferably 8.0 to 32.0 vol%, more preferably 10.5 to 30.0 vol%, and still more preferably 12.0 to 30.0 vol%.

When the content of the iron-based material is 8.0 vol% or more, the friction performance of the sintered friction material of the present invention can be further improved. When the content of the iron-based material is 32.0 vol% or less, the decrease in wear resistance due to the migration of the iron-based material to the material to be blended in the sintered friction material can be suppressed.

Examples of the iron-based material include: iron, and alloys containing iron such as steel and stainless steel, and the like. These may be used alone or in combination of two or more.

When the metal material contains tungsten, the content of tungsten in the sintered friction material of the present invention is preferably 1.0 to 15.0 vol%, more preferably 2.0 to 13.0 vol%, and still more preferably 3.0 to 11.0 vol%.

If the tungsten content is 1.0 vol% or more, the wear resistance of the sintered friction material of the present invention can be improved. If the content of tungsten is 15.0 vol% or less, the strength of the sintered friction material of the present invention can be ensured.

When the metal material contains tin, the content of tin in the sintered friction material of the present invention is preferably 5.0 vol% or less, more preferably 4.0 vol% or less, and still more preferably 3.0 vol% or less.

When the content of tin is more than 5.0 vol%, the homogeneity of the sintered friction material of the present invention may be reduced.

Examples of the shape of the metal material include a powder shape and a fiber shape.

(titanate)

The sintered friction material of the present invention contains titanate as a matrix. Titanates are compounds having high wear resistance and the like, and contribute to improvement of wear resistance and the like of sintered friction materials.

For example, when a resin-based friction material contains titanate as a filler, the heating temperature for producing the friction material is low. Therefore, in the case where the friction material contains a resin as a matrix, titanate exists in the friction material in the same shape as that when mixed as a filler. On the other hand, in the sintered friction material of the present invention, titanate is in a state after sintering, and forms a matrix.

Titanates contained as fillers in friction materials and titanates contained as matrices in sintered friction materials can be clearly distinguished by SEM (Scanning Electron Microscope) observation and the like.

The content of titanate in the sintered friction material of the present invention is preferably 8.0 vol% or more, more preferably 10.0 vol% or more, and still more preferably 12.0 vol% or more.

If the content of titanate is 8.0 vol% or more, titanate is sintered when the raw material containing titanate is molded and sintered, and a matrix of the friction material can be formed.

The content of titanate is preferably 60.0 vol% or less, more preferably 58.0 vol% or less, and still more preferably 55.0 vol% or less.

When the content of titanate is 60.0 vol% or less, components necessary for a friction material such as a grinding material and a lubricating material can be sufficiently contained.

In addition, titanate has a lower density than metals such as iron. Therefore, the sintered friction material of the present invention has a lower density and a lighter weight than an iron-based sintered friction material using only a metal such as iron as a base.

Examples of titanates include: alkali metal titanates such as potassium titanate, lithium titanate, and sodium titanate; alkaline earth metal titanates such as calcium titanate, barium titanate and magnesium titanate; and complex titanates such as lithium potassium titanate and magnesium potassium titanate. These may be used alone or in combination of two or more.

Among them, potassium titanate, sodium titanate, calcium titanate, lithium potassium titanate, and magnesium potassium titanate are preferable from the viewpoint of heat resistance and abrasion resistance.

In view of sanitary working environment, a titanate having a so-called non-whisker (fiber) shape such as a spherical shape, a plate shape, a scale shape, or a columnar shape is preferable.

< grinding Material >

The sintered friction material of the present invention preferably contains a grinding material. By containing the abrasive material, desired friction performance can be imparted to the sintered friction material of the present invention.

The content of the grinding material in the sintered friction material of the present invention is preferably 25.0 vol% or less, more preferably 23.0 vol% or less, and still more preferably 20.0 vol% or less.

If the content of the grinding material is 25.0 vol% or less, the sintered friction material of the present invention is likely to be inhibited from having too high an attack on the mating material.

Examples of the grinding material include: chromium oxide, zirconium oxide, silicon carbide, magnesium oxide, aluminum oxide, silicon dioxide, zirconium oxide, zirconium silicate, ferroferric oxide (Fe)₃O₄) Chromite, and the like. These may be used alone or in combination of two or more.

Among them, from the viewpoint of balancing the grindability and the aggressibility to a mating material, chromium oxide, zirconium oxide, silicon carbide, magnesium oxide, and aluminum oxide are preferable, and chromium oxide, zirconium oxide, and silicon carbide are more preferable.

< lubricating material >

The sintered friction material of the present invention preferably contains a lubricating material. By containing the lubricating material, seizure with the material to be blended in the sintered friction material of the present invention can be prevented, and the wear resistance of the sintered friction material of the present invention can be improved.

The content of the lubricant in the sintered friction material of the present invention is preferably 20.0 to 65.0 vol%, more preferably 30.0 to 65.0 vol%, and still more preferably 35.0 to 65.0 vol%, from the viewpoint of wear resistance.

Examples of the lubricant include: artificial graphite, natural graphite, coke, molybdenum disulfide, tin sulfide, iron sulfide, zinc sulfide, and the like. These may be used alone or in combination of two or more.

Among them, artificial graphite, natural graphite, and molybdenum disulfide are preferable from the viewpoint of sinterability and wear resistance.

< other ingredients >

The sintered friction material of the present invention may contain the above-mentioned components, but may contain other components other than the above-mentioned components. Examples of the other components include: inorganic fillers such as barium sulfate, calcium carbonate, calcium hydroxide, vermiculite, mica, mullite, silicon nitride, zircon sand, and the like. These may be used alone or in combination of two or more.

< copper component >

From the viewpoint of reducing the environmental load, the content of the copper component in the sintered friction material of the present invention is 0.5 mass% or less in terms of copper element. In addition, the sintered friction material of the present invention preferably does not contain a copper component.

[ method for producing sintered Friction Material ]

The method for producing a sintered friction material of the present invention comprises:

a mixing step of mixing a raw material containing a metal material other than copper and a titanate;

a molding step of molding the raw materials mixed in the mixing step; and

a sintering step of sintering the molded body molded in the molding step at 900 to 1300 ℃,

in the sintered friction material, the metal material other than copper and the titanate constitute a matrix, and the content of the metal material other than copper is 10.0-34.0 vol%.

The mixing method used in the mixing step is not particularly limited as long as the raw materials are uniformly mixed, and a known method can be used. For example, the following method may be used: an appropriate amount of an organic solvent is added to the raw materials as needed, and wet mixing is performed using a rotary mixer or the like to uniformly disperse the raw materials.

Next, a molding step is performed to mold the raw materials mixed in the mixing step.

In the molding step, a dry molding method such as uniaxial press molding or CIP molding (cold isostatic press molding) can be suitably used; plastic molding methods such as injection molding and extrusion molding; casting molding methods such as slurry casting, pressure casting, and spin casting; band forming methods such as a doctor blade method; cold stamping, and the like. The above-mentioned molding methods may be used alone, or 2 or more kinds may be used in combination.

From the viewpoint of moldability, the molding surface pressure in the molding step is preferably 300 to 900 MPa.

Next, a sintering step is performed to sinter the molded body molded in the molding step.

In the sintering step, the molded body can be sintered by a hot pressing method, an atmosphere sintering method, a reaction sintering method, an atmospheric pressure sintering method, a thermal plasma sintering method, or the like.

The sintering temperature in the sintering step is 900 to 1300 ℃, preferably 900 to 1250 ℃, and more preferably 900 to 1200 ℃. If the sintering temperature is lower than 900 ℃, the substrate may become brittle. If the sintering temperature is higher than 1300 ℃, the raw material may start to melt.

From the viewpoint of sinterability, the holding time in the sintering step is preferably 30 to 180 minutes.

In the sintering step, it is preferable to sinter the molded article while applying pressure thereto. The sintering surface pressure at this time is preferably 1 to 18MPa from the viewpoint of sinterability.

Depending on the types of the metal material and titanate constituting the matrix, the types of other materials, and the like, the sintering step may be performed in the atmosphere or in an inert gas such as nitrogen gas or argon gas, or may be performed in a reducing gas such as carbon monoxide gas or hydrogen gas. The sintering step may be performed in vacuum.

The sintered body obtained through the above steps is subjected to a treatment such as cutting, grinding, polishing, etc., as necessary, thereby producing the sintered friction material of the present invention.

[ examples ]

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples at all.

[ test example 1]

< examples 1-1 to 1-8 and comparative examples 1-1 to 1-4 >

The raw materials having the formulation composition (vol%) shown in table 1 were mixed by using a mixer. The obtained raw material mixtures were molded by cold stamping under a molding surface pressure of 520 MPa.

Each of the molded bodies thus obtained was put into a graphite mold and sintered by a hot press method to obtain sintered friction materials of examples 1-1 to 1-8 and comparative examples 1-1 to 1-4.

The sintering conditions in the hot press method are as follows.

Sintering surface pressure: 3MPa

Sintering temperature: 950 ℃ C

Sintering retention time: 120 minutes

[ evaluation of Friction Properties ]

The sintered friction materials of examples 1-1 to 1-8 and comparative examples 1-1 to 1-4 were subjected to a dynamometer test with reference to JASO C406 under the following test conditions, and the average values of the wear loss and the friction coefficient μ of each sintered friction material were measured. The results are shown in Table 1.

(test conditions)

Disc effective radius: 250mm

Area of friction material: 15.2cm²

The diameter of the cylinder body is as follows: 40.45mm

Inertia: 7kg m²

(method of evaluating abrasion loss)

The wear amount of the sintered friction material after the dynamometer test was completed was measured with a micrometer.

(method of evaluating Friction coefficient. mu.)

The coefficient of friction μ was measured under the following test conditions.

Initial speed: 100km/h

Pressing pressure: 1.0 MPa-10.0 MPa (1.0MPa scale)

The times are as follows: 1 time (10 times in total) for each pressing pressure

Brake disc temperature: 95 deg.C

The measurement result is determined based on the following criteria. The results are shown in Table 1.

(amount of wear)

O: the wear loss of the sintered friction material is 6.50mm or less.

X: the wear loss of the sintered friction material is greater than 6.50 mm.

(average value of coefficient of friction. mu.)

O: the average value of the friction coefficient mu is 0.20 or more.

X: the average value of the friction coefficient mu is less than 0.20.

[ Table 1]

From the results in Table 1, it is clear that the sintered friction materials of examples 1-1 to 1-8 have sufficient friction performance even in the high-speed region. For the sintered friction materials of comparative examples 1-1 and comparative examples 1-2, the content of the metallic material was outside the range of the present invention. The sintered friction materials of comparative examples 1 to 3 did not contain any metal material at all, and contained only a predetermined amount of titanate as a matrix. For the sintered friction materials of comparative examples 1 to 4, the content of the metallic material was outside the range of the present invention, and titanate was not contained at all. It is found that the friction performance of the sintered friction materials of all comparative examples is lower than that of the sintered friction materials of examples 1-1 to 1-8.

[ test example 2]

< examples 2-1 to 2-9, comparative example 2-1 >)

The raw materials having the formulation composition (vol%) shown in table 2 were mixed by using a mixer. The obtained raw material mixtures were molded by cold stamping under a molding surface pressure of 520 MPa.

Each of the molded bodies thus obtained was put into a graphite mold and sintered by a hot press method to obtain sintered friction materials of examples 2-1 to 2-9 and comparative example 2-1.

The sintering conditions in the hot press method are as follows.

Sintering surface pressure: 2MPa of

Sintering temperature: 950 ℃ C

Sintering retention time: 120 minutes

[ evaluation of Friction Properties ]

The sintered friction materials of examples 2-1 to 2-9 and comparative example 2-1 were subjected to a fading test under the following test conditions, and the wear amounts of the respective sintered friction materials and the rotor wear amount were measured. The results are shown in Table 2.

(test conditions)

Initial speed: 240km/h

Final speed: 90km/h

Deceleration rate: 8m/s²

First-brake rotor temperature: 120 deg.C

The braking times are as follows: 25 times (19 times in comparative example 2-1)

Clearance: 30 seconds

(method of evaluating wear amount of sintered Friction Material)

The wear amount of the sintered friction material after the end of the fade test was measured with a micrometer and converted into the wear amount per 1 brake.

(method of evaluating rotor wear amount)

The wear amount of the rotor after the end of the fading test was measured by a micrometer and converted into the wear amount per 1 braking.

[ Table 2]

As is clear from the results in Table 2, the sintered friction materials of examples 2-1 to 2-9 have sufficient friction performance even in the high-speed region.

The present invention has been described in detail with reference to specific embodiments, but it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. The present application is based on japanese patent application filed on 31/10/2018 (japanese patent application 2018-205687) and on 25/9/2019 (japanese patent application 2019-174044), the contents of which are incorporated herein by reference.

Industrial applicability

The sintered friction material is an environment-friendly friction material with the copper content below a certain amount. In addition, the sintered friction material of the present invention has sufficient friction performance in a high speed region.

The sintered friction material can be used for the brake of the integral transportation equipment such as passenger vehicles, commercial vehicles, two-wheel vehicles, railways and the like or industrial machinery and the like.

Claims (6)

Translated fromChinese

1.一种烧结摩擦材料，其特征在于，1. A sintered friction material, characterized in that,铜成分的含量为0.5质量％以下，The content of the copper component is 0.5 mass % or less,含有铜以外的金属材料和钛酸盐作为基体，Contains metal materials other than copper and titanate as a matrix,所述铜以外的金属材料的含量为10.0～34.0体积％。The content of the metal material other than the copper is 10.0 to 34.0% by volume.2.根据权利要求1所述的烧结摩擦材料，其特征在于，2. The sintered friction material according to claim 1, characterized in that,所述钛酸盐含有选自由碱金属钛酸盐、碱土金属钛酸盐和复合钛酸盐组成的组中的至少1种盐。The titanate contains at least one salt selected from the group consisting of alkali metal titanates, alkaline earth metal titanates, and complex titanates.3.根据权利要求1或2所述的烧结摩擦材料，其特征在于，3. The sintered friction material according to claim 1 or 2, characterized in that,所述钛酸盐含有选自由钛酸钾、钛酸钠、钛酸钙、钛酸锂钾及钛酸镁钾组成的组中的至少1种盐。The titanate contains at least one salt selected from the group consisting of potassium titanate, sodium titanate, calcium titanate, lithium potassium titanate, and magnesium potassium titanate.4.根据权利要求1～3中任一项所述的烧结摩擦材料，其特征在于，4. The sintered friction material according to any one of claims 1 to 3, wherein所述铜以外的金属材料含有铁系材料，所述铁系材料的含量为8.0～32.0体积％。The metal material other than the copper contains an iron-based material, and the content of the iron-based material is 8.0 to 32.0% by volume.5.根据权利要求1～4中任一项所述的烧结摩擦材料，其特征在于，5. The sintered friction material according to any one of claims 1 to 4, wherein所述铜以外的金属材料还含有钨，钨的含量为1.0～15.0体积％。The metal material other than copper further contains tungsten, and the content of tungsten is 1.0 to 15.0% by volume.6.一种烧结摩擦材料的制造方法，其特征在于，包括：6. A method for manufacturing a sintered friction material, comprising:混合工序，对含有铜以外的金属材料和钛酸盐的原材料进行混合；Mixing process, mixing raw materials containing metal materials other than copper and titanate;成型工序，对在所述混合工序中混合后的原材料进行成型；以及a forming step of forming the raw materials mixed in the mixing step; and烧结工序，在900～1300℃下对在所述成型工序中成型后的成型体进行烧结，In the sintering step, the molded body molded in the molding step is sintered at 900 to 1300° C.,所述烧结摩擦材料中，所述铜以外的金属材料和所述钛酸盐构成基体，所述铜以外的金属材料的含量为10.0～34.0体积％。In the sintered friction material, the metal material other than copper and the titanate constitute a matrix, and the content of the metal material other than copper is 10.0 to 34.0% by volume.