CN102348906A

CN102348906A - Friction pair

Info

Publication number: CN102348906A
Application number: CN2010800115734A
Authority: CN
Inventors: 阿部健司; 西胁正明; 矶野宏; 盐见幸广; 藤川裕之; 若松智之; 志村好男; 长泽裕二
Original assignee: Advics Co Ltd; Toyota Motor Corp
Current assignee: Advics Co Ltd; Toyota Motor Corp
Priority date: 2009-03-10
Filing date: 2010-03-09
Publication date: 2012-02-08
Also published as: JP2010209214A; WO2010103369A1; DE112010001176T5

Abstract

A friction pair that generates factional force through mutual factional sliding includes: a first friction material (1) that contains first hard particles (11) and a resin (12) with a lower Mohs hardness than the first hard particles (11); and a second friction material (2) that contains second hard particles (21) and either a metallic material or an inorganic material (24) with a lower Mohs hardness than the second hard particles (21) and a higher Mohs hardness than the resin (12). The resin (12) of the first friction material (1) surrounds the entire surface of the first hard particles (11) and the metallic material or inorganic material (24) of the second friction material (2) forms a matrix in which the second hard particles (21) are embedded.

Description

It is right to rub

Technical field

The present invention relates to show that the friction of good wear resistance, noise performance, vibration performance and braking ability is right.

Background technique

In order to ensure Security, the high-performance that brake rim, brake lining, clutch facing and other friction materials that is used for industrial machinery, railway vehicle, goods transport vehicle, passenger car etc. need have high reliability and increase day by day.More specifically, because friction material is converted into heat through friction with kinetic energy, so they must have enough heat resistances for the frictional heat that during braking, produces.In addition; Consider from operation stability; Friction material must also show the frictional behaviour that keeps constant under temperature and weather condition variation, have the superior abrasion resistance of the very little variation of performance generation in long time period, and during braking or Vehicular vibration, can not produce noise such as squeal.Especially, consider, think that noise and the vibration owing to the frictional vibration of friction material is the important techniques problem from the peace and quiet of value of the product and vehicle.

In order to satisfy these needs, use several one-tenth to assign to form friction material through combination usually.For example, the various combinations of filler of be used to keep the fiber base material of friction material shape, the composition such as fiber base material being carried out bonding tackiness agent and is used to regulate the various performances (such as the adjusting of wear resistance, heat resistance or friction factor and stable) of friction material.Through utilizing hot pressing to be cured, carry out moulding, grinding in case of necessity and size classification (size) material that creates friction subsequently to utilizing mixer that these compositions are mixed the raw mix that obtains.In order to improve the braking ability of friction material, be blended in the friction material with high hardness and to the extremely effective hard particles of the friction factor that improves friction material.Although the amount through increasing hard particles can improve braking ability, hard particles can make that pairing material is worn.The concentrated wear that is caused by hard particles causes the uneven wear of the friction surface of pairing material, and the wear debris that is derived from the pairing material of wearing and tearing simultaneously can remain on the friction surface, thus the wearing and tearing of the right friction surface that aggravated to rub.As a result, the wear resistance of friction material possibly descend, and is easier to produce noise and vibration simultaneously.Thus, be difficult to when guaranteeing excellent abrasive, noise performance and vibration performance, keep the high braking ability of friction material.

In order to address the above problem, for example, TOHKEMY 2003-268352 (JP-A-2003-268352) has described a kind of friction material that contains substrate fiber, tackiness agent and friction modifiers.Said friction modifiers contains the high elasticity abrasives that is made up of porous hard particles and the high elasticity material that is fixed in the hole of said porous hard particles.

Relate to a kind of right friction material of friction that constitutes in the invention described in the JP-A-2003-268352.Yet the braking ability of friction material and wear resistance are decided by the combination of materials of the friction centering that constitutes friction surface.Therefore, it is right to be difficult to obtain to give full play to the friction of estimated performance through the performance that only improve to constitute the right a kind of friction material of friction.Particularly, through concentrating on the material design on the friction surface that constitutes the first right friction material of friction and second friction material, can access friction material with excellent abrasive, noise performance, vibration performance and braking ability.Even if only a kind of friction material is designed, also need with study and evaluation aspect need the method for trial and error repeatedly, the pairing friction material that is fit to above-mentioned friction material is designed separately.Therefore, carry out co-design, can in the right exploitation of friction, save cost and time, and can improve the performance that rubs right and predict constituting the right friction material of friction.

Summary of the invention

The present invention provides a kind of friction with wear resistance, noise performance, vibration performance and braking ability right.

According to the friction of first aspect present invention to producing frictional force through mutual friction slip; And comprise: first friction material; Said first friction material comprises first hard particles and the low resin of said first hard particles of Mohs (Mohs) hardness ratio, and wherein said resin covers the whole surface of said first hard particles; With second friction material; Said second friction material contains second hard particles and Mohs hardness is lower than said second hard particles and Mohs hardness is higher than said resin metallic material or inorganic material; Wherein said metallic material or inorganic material constitute the matrix of said second friction material, and said second hard particles is embedded in the matrix of said second friction material.

Said friction is to having stress distribution mechanism; Even thus stress said friction on, the stress that is applied on said first hard particles or said second hard particles also can fully be absorbed by said resin, said metallic material or said inorganic material.As a result, said first hard particles or said second hard particles more are not vulnerable to the above stress of yield stress.Therefore, utilize said first hard particles and said second hard particles, said friction realizes excellent frictional force stability simultaneously and suppresses noise and vibration producing high frictional force.

Above-mentioned friction centering; Said first friction material can also contain the elastic material of the matrix that constitutes said first friction material, and wherein said first hard particles is embedded in the matrix of said first friction material by the resin-coated hard particles of said resin-coated.Said friction is to can also satisfying at least one in following first to the 4th condition:

1. said first friction material also contains Mohs hardness first inorganic particulate lower than said first hard particles, and the average diameter r of said resin-coated hard particles _cAverage diameter r with respect to said first inorganic particulate _fFirst ratio r _c/ r _fBe at least 0.2;

2. said second friction material also contains Mohs hardness second inorganic particulate lower than said second hard particles, the average diameter R of said second hard particles _AAverage diameter R with respect to said second inorganic particulate _FSecond ratio R _A/ R _FBe at least 0.2;

3. said first friction material satisfies following formula (1); And

4. said first friction material and said second friction material satisfy following formula (2).

s \leq \frac{r_{a} \cdot E_{b}}{2 (E_{m} - E_{b})}

Formula (1)

In formula (1), s is the average coating thickness of said resin in said resin-coated hard particles, E _bBe the Young's modulus of said resin, E _mBe the Young's modulus of said elastic material, and r _aBe the average diameter of said first hard particles, and E _m＞E _b

0.2 \leq (\frac{σ_{2}}{σ_{1}}) \cdot (\frac{{\overset{&OverBar;}{C}}_{A}}{C_{a}}) \cdot {(\frac{R_{A}}{r_{a}^{\cdot}})}^{2} \leq 5

Formula (2)

In formula (2), C _aBe the concentration (volume %) of first hard particles described in said first friction material, C _ABe the concentration (volume %) of second hard particles described in said second friction material, r _aBe the average diameter of first hard particles described in said first friction material, R _ABe the average diameter of second hard particles described in said second friction material, σ ₁Be the yield stress of said first friction material, and σ ₂Be the yield stress of said second friction material, and σ ₁=10～100MPa, σ ₂=100～800MPa and C _A=0.1～95 volume %.

Have the friction centering of above-mentioned characteristic, the elastic material in first friction material guarantees that the whole friction surface of friction material can be in contact with one another.This makes can produce frictional force between whole friction surface.When the friction with above-mentioned characteristic when satisfying first condition, first ratio r _c/ r _fBe at least 0.2.The result; When even the resin-coated hard particles is arranged in the center of the close-packed structure that is formed by four first inorganic particulates; The compressive stress that in first friction material, produces also is applied on the resin-coated hard particles, and stress still runs through first friction material and evenly transmission.If the friction with above-mentioned characteristic is to satisfying second condition, second ratio R then _A/ R _FBe at least 0.2.As a result, even when second hard particles is arranged in the center of the close-packed structure that is formed by four second inorganic particulates, the compressive stress that in second friction material, produces also is applied on the hard particles, and stress still runs through second friction material and evenly transmit.When the friction with above-mentioned characteristic when also satisfying the 3rd condition, through suitable coating thickness s is set, make stress concentrate in first hard particles.In addition, when the friction with above-mentioned characteristic when also satisfying the 4th condition, can suppress the generation of surrendering in first hard particles and second hard particles.

Friction is to can also satisfying whole said first condition to the four conditions.

Above-mentioned friction centering, at least a in first hard particles and second hard particles has at least 4.5 Mohs hardness.

Friction with above-mentioned characteristic is to producing higher frictional force when realizing excellent frictional force stability and suppressing noise and vibration.Has the friction of above-mentioned characteristic has high yield stress to use hard particles.As a result, in hard particles, be difficult for surrendering, because act on the displacement that stress on first and second friction materials only causes the hard particles composition on every side at material outmost surface place.This has reduced the wearing and tearing of friction material and has improved its wear resistance.

Above-mentioned friction is to can satisfying the 3rd condition, and the elastic modulus E of resin _bCan be 1GPa at least.

Above-mentioned friction centering, the resin with enough Young's modulus has prevented that first hard particles comes off when first friction material is rubbed from first friction material.In addition, friction is to realizing the stress preferably that first hard particles stands and first hard particles overhang preferably from first friction surface.Said friction is surrendered also being suppressed in first hard particles.

Above-mentioned friction centering, said resin can contain at least a non-crystalline resin that is selected from polyamide, polyamidoimide, polycarbonate (PC), PPO, polyene propyl ester (polyallylate), polysulfones, the polyether sulfone.

Select suitable non-crystalline resin can produce stress preferably that first hard particles stands and first hard particles overhang preferably from first friction surface.

Above-mentioned friction be to can satisfying at least one in first condition and the second condition, and at least a in first inorganic particulate and second inorganic particulate has and be no more than 4 Mohs hardness.

Friction with above-mentioned characteristic has at least a in first inorganic particulate and second inorganic particulate of low yield stress to use.Therefore, when said first and second friction materials stood stress, at least a in first hard particles in the resin-coated hard particles and second hard particles can not broken.This makes and can in friction material, reduce the wear resistance of wearing and tearing and realizing expectation.

Above-mentioned friction is to can satisfying the 3rd condition, and the elastic modulus E of said elastic material _mCan be 1GPa at least.

Have the friction centering of above-mentioned characteristic, the elastic material with enough Young's modulus has been realized stress preferably that first hard particles stands and first hard particles overhang preferably from first friction surface.

Said elastic material can contain at least a resin that is selected from phenolic resin, phenol-formaldehyde resin modified, amino resin, furan, unsaturated polyester resin, diallyl phthalate resin, alkyd resin, epoxy resin, thermosetting polyamide imide resin, thermoset polyimide resin and the organic siliconresin.

Have the friction centering of above-mentioned characteristic, selecting the stress preferably that suitable elastic materials realized that first hard particles stands and first hard particles overhang preferably from first friction surface.

Above-mentioned friction is to can satisfying at least one in first condition and the second condition, and first ratio r _c/ r _fWith second ratio R _A/ R _FIn at least one can be at least 0.3.Perhaps, first condition and second condition can satisfy simultaneously, and first ratio and second ratio can all be more than 0.3.

Friction with above-mentioned characteristic is to providing at least a in the following effect.Be under at least 0.3 the condition at first ratio; Even the resin-coated hard particles is arranged in the center of the close-packed structure that is formed by four first inorganic particulates; When in first friction material, producing compressive stress, still can in the resin-coated hard particles, produce stress more reliably.For at least 0.3 the time,, when in second friction material, producing compressive stress, still can in second hard particles, produce stress more reliably at second ratio even second hard particles is arranged in the center of the close-packed structure that is formed by four second inorganic particulates.

Said first friction material can contain resin-coated hard particles and the elastic material of total at least 5 volume %, and said resin-coated hard particles can be 2: 1～1: 50 to the volume ratio of said elastic material.

Having the friction centering of above-mentioned characteristic, when first friction material comprises resin-coated hard particles and elastic material with amount preferably, can realize excellent frictional force stability and suppress noise and vibration.And, above-mentioned friction centering,, then can realize excellent frictional force stability and suppress noise and vibration if the volume ratio of resin-coated hard particles and elastic material drops in the suitable scope.

Above-mentioned friction centering, the Young's modulus of first friction material can be 100～300MPa.

Friction with above-mentioned characteristic is right, when friction, can prevent that first hard particles from coming off from first friction material.In addition, said friction is to having realized the stress preferably that first hard particles stands and first hard particles overhang preferably from first friction surface.Friction with above-mentioned characteristic is surrendered in first hard particles also having suppressed.

Above-mentioned friction centering, the surface roughness of the friction surface of second friction material can be not more than 10 μ m.

Friction with above-mentioned characteristic has been to providing good initial break-in (break-in), and can suppress the variation of frictional force and the increase of wearing and tearing.

Description of drawings

In the following detailed description of embodiment of the present invention, with reference to the accompanying drawings characteristic of the present invention, advantage and technology and industrial significance are described, the key element that wherein identical numeral is identical, and wherein:

Fig. 1 is the schematic representation that shows the resin-coated hard particles, and said resin-coated hard particles occupies the space in the close-packed structure that is formed by the inorganic particulate in first friction material;

Fig. 2 is the figure that schematically shows by condition (4) restricted portion, and wherein X-axis is represented (r _a/ R _A) ²And Y-axis is represented (C _a/ C _A);

Fig. 3 shows the rub figure of right representative instance of the present invention;

Fig. 4 A and 4B show that stress applies the schematic cross-sectional view of the right representative instance of front and back friction; And

Fig. 5 is presented at stress to friction material the time, partly is in the resin-coated hard particles (c) and is constituting the schematic cross-sectional view that the comparison situation of strain front and back takes place in the elastic material (m) of matrix of friction material at friction surface.

Embodiment

To producing frictional force through mutual friction slip, said friction is to comprising according to the friction of first aspect present invention: first friction material, said first friction material comprise hard particles (a) and cover the resin (b) on the whole surface of said hard particles (a); With second friction material; Said second friction material contains hard particles (A) and metallic material or inorganic material (M); Said metallic material or inorganic material (M) constitute the matrix of said second friction material, and said hard particles (A) is embedded in the matrix of said second friction material.The Mohs hardness of the resin of said first friction material (b) is lower than the Mohs hardness of said hard particles (a), and the Mohs hardness of the metal of second friction material or inorganic material (M) is lower and higher than the Mohs hardness of resin (b) than the Mohs hardness of hard particles (A).

In the right instance of the friction of practical implementation first aspect present invention; Said first friction material preferably contains resin-coated hard particles (c) and elastic material (m); Resin (b) coats hard particles (a) in said resin-coated hard particles (c); And said elastic material (m) constitutes the matrix of said first friction material, and wherein the resin-coated particle is embedded in the matrix of said first friction material; And said second friction material contains hard particles (A) and constitutes the metallic material or the inorganic material (M) (" host material " hereinafter) of the matrix of second friction material, wherein rubs to satisfying at least one in following condition (1)～(4):

(1) said first friction material also contains the Mohs hardness inorganic particulate (f) lower than said hard particles (a), and the average diameter r of resin-coated hard particles (c) _cAverage diameter r with respect to inorganic particulate (f) _fRatio r _c/ r _fBe at least 0.2.

(2) said second friction material also contains the Mohs hardness inorganic particulate (F) lower than said hard particles (A), the average diameter R of said hard particles (A) _AAverage diameter R with respect to inorganic particulate (F) _FRatio R _A/ R _FBe at least 0.2.

(3) said first friction material satisfies following formula (1).

(4) said first friction material and said second friction material satisfy following formula (2).

s \leq \frac{r_{a} \cdot E_{b}}{2 (E_{m} - E_{b})}

Formula (1)

In formula (1), s is the average coating thickness of resin (b) on resin-coated hard particles (c), E _bBe the Young's modulus of resin (b), E _mBe the Young's modulus of elastic material (m), and r _aBe the average diameter of hard particles (a), and E _m＞E _b

0.2 \leq (\frac{σ_{2}}{σ_{1}}) \cdot (\frac{{\overset{&OverBar;}{C}}_{A}}{C_{a}}) \cdot {(\frac{R_{A}}{r_{a}^{\cdot}})}^{2} \leq 5

Formula (2)

In formula (2), C _aBe the concentration (volume %) of hard particles in first friction material (a), C _ABe the concentration (volume %) of hard particles in second friction material (A), r _aBe the average diameter of hard particles in first friction material (a), R _ABe the average diameter of hard particles in second friction material (A), σ ₁Be the yield stress of first friction material, and σ ₂Be the yield stress of second friction material, and σ ₁=10～100MPa, σ ₂=100～800MPa and C _A=0.1～95 volume %.

Said friction is to comprising first friction material and second friction material.The right concrete application that rubs comprises for example disk type braker, and wherein said friction is to having as the liner of first friction material with as the rotor of second friction material.

" Mohs hardness " is the representative hardness index that is used to represent mineral resources hardness, and its scope is to 1 of talcum from adamantine 10.

Routine friction centering, as yet not on science to the average diameter of the hardness of hard particles the friction material and hardness ratio, hard particles with average diameter compares and the adding quantity and the adding quantity ratio of hard particles are studied.Therefore, wear resistance still exists with the problem that suppresses noise and vibration, and irrelevant with the frictional force of friction material.On the contrary, no matter rub right wear resistance and noise and vibration suppressioning effect maybe how high, still possibly obtain to be difficult to show that the friction of high frictional force is right.Therefore, be difficult to when keeping high frictional force, realize wear resistance simultaneously and suppress noise and vibration.

Hard particles is the important component that is used to improve the friction factor of friction surface and guarantees the braking ability of friction material.Said hard particles has high yield stress, therefore when friction material stands stress, is difficult in hard particles, surrendering.

The hardness of said hard particles can cause excessive wear in pairing material.If pairing material also contains hard particles, the hard particles in then a kind of friction material alternately and hard particles in the pairing material that rubs off and on and the composition outside the hard particles.This possibly cause that the right friction of friction changes.Perhaps, the friction between the hard particles can make the hard particles at least a material break.Remain in the hard particles that breaks in the friction surface, possibly promote the wearing and tearing in friction material and pairing material at least a again.

Therefore, for when keeping high frictional force, realizing wear resistance simultaneously and suppress noise and vibration, is inadequate as in the conventional friction material, only developing friction material separately.On the contrary, friction material must be designed to the combination of centering material that rubs, and must control the composition ratio of hard particles in each friction material etc.

To having first friction material and second friction material, said first friction material and second friction material have the elastic material outside hard particles and the hard particles separately according to the friction of first aspect present invention.And, friction centering, set up stress distribution mechanism and material design method and stood the stress more than the yield stress to prevent hard particles.

Set up this stress distribution mechanism and material design method and will in friction material, the partial fracture in the elastic material except that hard particles be limited to the only strain of the outmost surface layer of friction material, make partial fracture be difficult for propagating into friction material inside thus.Thus, when keeping high frictional force, can realize suitable wear resistance and suppress noise and vibration.

Particularly, above-mentioned stress distribution mechanism is the next kinetic mechanism of hard particles from the overhang of friction surface that fully reduce of distortion through the elastic material that in various friction materials, covers hard particles.If hard particles is outstanding from friction surface; Then not only in the friction that takes place between the top of the projection of first friction material and second friction material between the hard particles, and the friction between the hard particles also takes place in the zone outside the top of said projection.Therefore, how no matter to be considered to anti abrasive hard particles, all can not to avoid the wearing and tearing of essence.Above-mentioned stress distribution mechanism has solved this problem.Above-mentioned mechanism is controlled the stress that acts on each hard particles in first and second friction materials, makes hard particles without undergoing the stress more than the yield stress, and makes the only phase mutual friction at the top of projection of hard particles.As a result, can when keep high frictional force, improve wear resistance simultaneously and suppress noise and vibration.

Particularly, the above-mentioned material design method is a kind of relating to being present in the scientific method that hard particles in the various friction materials, the average diameter, blending amount, Young's modulus etc. of elastic material and other materials outside the hard particles are regulated.Although above-mentioned stress distribution mechanism has solved the problems referred to above, said mechanism is from studying and the evaluation aspect relates to trial and error repeatedly in friction is right, and is difficult to predict the raising of the performance that is provided by said mechanism.So the friction of developing the best of breed with friction material is to becoming a kind of trial consuming time.Through the various parameters that are present in the various materials in first and second friction materials such as average diameter, blending amount, Young's modulus etc. are carried out scientific design, can shorten the right development time of friction, and can predict the raising of friction performance.

Have above-mentioned stress distribution mechanism and according to the right instantiation of the friction of above-mentioned material designing method in; Friction is to comprising first friction material; Said first friction material contains wherein that hard particles (a) is coated with the resin-coated hard particles (c) of resin (b) and the elastic material (m) outside the said resin-coated hard particles, and said elastic material (m) constitutes the matrix of said first friction material; With second friction material, said second friction material contains hard particles (A) and host material (M), and wherein said friction is to satisfying at least a in following condition (1)～(4).In addition, also can utilize resin that the hard particles in second friction material (A) is coated.

In condition (1), " first friction material also contains the Mohs hardness inorganic particulate (f) lower than hard particles (a), and the average diameter r of resin-coated hard particles (c) _cAverage diameter r with respect to inorganic particulate (f) _fRatio (r _c/ r _f) for being not less than 0.2 ".In condition (2), " second friction material also contains the Mohs hardness inorganic particulate (F) lower than said hard particles (A), and the average diameter R of said hard particles (A) _AAverage diameter R with respect to inorganic particulate (F) _FRatio (R _A/ R _F) for being not less than 0.2 ".

Fig. 1 is the schematic representation that shows the resin-coated hard particles, and said resin-coated hard particles occupies the space in the close-packed structure that is formed by the inorganic particulate in first friction material.The inorganic particulate (f) 61 that draws with solid line and draw and more form close-packed structures near the inorganic particulate (f) 62 of the front of paper than the former with dotted line.The space that said resin-coated hard particles (c) 63 occupies in the close-packed structure.Suppose

inorganic particulate

61 and 62 and resin-coated hard particles 63 for spherical.In Fig. 1,, drawn inorganic particulate 62 with transparent way in order to show resin-coated hard particles 63.

When the space (tetrahedron space) that resin-coated hard particles 63 is fixed on tightly close-packed structure was middle, the diameter of resin-coated hard particles 63 was 0.225r _f≈ 0.2r _f, r wherein _fIt is the diameter of inorganic particulate (f) 61 and 62.Therefore, if resin-coated hard particles 63 has the diameter that is equal to or greater than above-mentioned value, promptly work as r _cWith respect to r _fRatio (r _c/ r _f) be equal to or greater than 0.2, r wherein _cWhen being the diameter of resin-coated hard particles (c); Any compressive stress that in first friction material, produces all not only is applied on the inorganic particulate (f); And be applied on the resin-coated hard particles (c); When even resin-coated hard particles (c) is arranged in the center of the close-packed structure that is formed by four inorganic particulates (f) thus, said stress still can run through said first friction material and evenly transmit.

Relation object between inorganic particulate in second friction material (F) and the hard particles (A) seemingly.Particularly, work as R _AWith respect to R _FRatio (R _A/ R _F) be equal to or greater than 0.2, R wherein _FBe the average diameter and the R of inorganic particulate (F) _AWhen being the average diameter of hard particles (A); Any compressive stress that in second friction material, produces all not only is applied on the inorganic particulate (F); And be applied on the hard particles (A); When even hard particles (A) is arranged in the center of the close-packed structure that is formed by four inorganic particulates (F) thus, said stress still can run through said second friction material and evenly transmit.

In condition (1) or (2), said inorganic particulate (f) or (F) have as the inorganic substances of the friction modifiers of various friction materials for example.Can be used in inorganic particulate (f) or concrete material (F) and can comprise for example carbon, pottery, oxide such as iron oxide or cupric oxide, mineral filler such as barium sulphate or calcium carbonate, metallic dust such as copper powders may or brass powder or solid lubricant such as graphite or molybdenum disulfide.

In condition (1), the Mohs hardness of inorganic particulate (f) and inorganic particulate (F) preferably is no more than 4, and it is enough to when realizing excellent frictional force stability and suppressing noise and vibration, higher frictional force is provided.If all use Mohs hardness to surpass 4 inorganic particulate among both at first and second friction materials; Then inorganic particulate has high yield stress; If therefore when resin-coated hard particles (c) and inorganic particulate (f) when contacting and when hard particles (A) and inorganic particulate (F) when contacting first and second friction materials stand stress, then at least a hard particles (a, A) in the resin-coated hard particles or second friction material is easier to break.As a result, wearing and tearing increase in various friction materials, possibly be difficult to the wear resistance that obtains to expect thus.Especially, at least a Mohs hardness in the above-mentioned inorganic particulate is most preferably not exceeding 3 more preferably no more than 3.5.

Preferably, r in condition (1) _c/ r _fFor at least 0.3 and/or in condition (2) R _A/ R _FBe at least 0.3.Ratio r _c/ r _fEven make resin-coated hard particles (c) be arranged in the center of the close-packed structure that forms by four inorganic particulates (f) at least 0.3, when in first friction material, producing compressive stress, also generation stress in resin-coated hard particles (c) more reliably.Ratio R _A/ R _FEven make hard particles (A) be arranged in the center of the close-packed structure that forms by four inorganic particulates (F) at least 0.3, when in above-mentioned second friction material, producing compressive stress, also generation stress in hard particles (A) more reliably.

For example, use laser diffraction or scattering method (little tracing) average diameter r to inorganic particulate (f) _f, inorganic particulate (F) average diameter R _F, resin-coated hard particles (c) average diameter r _cAnd the average diameter R of hard particles (A) _AMeasure.

In condition (3), first friction material satisfies following formula (1).

s \leq \frac{r_{a} \cdot E_{b}}{2 (E_{m} - E_{b})}

Formula (1)

In formula (1), s is the average coating thickness of resin (b) in resin-coated hard particles (c), E _bBe the Young's modulus of resin (b), E _mBe the Young's modulus of elastic material (m), and r _aBe the average diameter of hard particles (a), and E _m＞E _b

Fig. 5 comparatively is presented at stress to friction material the time, and the schematic cross-sectional view of the situation of strain front and back takes place in the resin-coated hard particles (c) that friction surface is partly located and in the elastic material (m) of the matrix that constitutes friction material.In said schematic representation, show the transverse section of resin-coated hard particles (c) with the form that applies the sectional drawing of the zonule of great circle portion on the direction at pressure.Likewise, the transverse section of elastic material (m) is expressed as the sectional drawing that has with the part of resin-coated hard particles (c) equal length.In order to stress strain, the transverse section is depicted as band.In Fig. 5, before friction material stands stress, elastic material (m) 71m and resin-coated hard particles (c) 73c are placed on the friction surface 70.Utilize dotted line to come elastic material 71m and particle 73c in the depiction 5.Elastic material (m) 72m and resin-coated hard particles (c) 74c be depicted as be presented at the stress σ that will produce because of friction by on the direction shown in the arrow among Fig. 5 _mAnd σ _cAct on the situation to elastic material 71m and particle 73c.In Fig. 5, utilize solid line to describe elastic material 72m and particle 74c.Said particle 73c contains hard particles (a) 73a and resin-coated (b) 73b, and particle 74c contains hard particles (a) 74a and resin-coated (b) 74b.As shown in Figure 5, r _aBe the average diameter of hard particles 73a and the average coating thickness that s is resin-coated 73b.

As stress σ _cWhen acting on the resin-coated hard particles 74c, stress σ _aActing on hard particles 74a goes up and stress σ _bAct on the resin-coated 74b.Because arrange resin-coated hard particles 74c, hard particles 74a and resin-coated 74b, stress sheet can be shown σ with coaxial mode _a=σ _b=σ _c=ε _bE _b=ε _aE _a(formula (1a)).In formula (1a), ε _aAnd ε _bRepresent the strain among hard particles 74a and the resin-coated 74b respectively, and E _aAnd E _bThe Young's modulus of representing hard particles 74a and resin-coated 74b respectively.Usually, Eb＜＜Ea, therefore, think ε _a=ε _b(E _b/ E _a) ≈ 0.Therefore, strain (displacement amount) ε of hard particles 74a in resin-coated hard particles 74c _aCan ignore, therefore, can be with ε _bBe expressed as ε _b≈ ε _c=γ/(2s) (formula (1b)), wherein ε _cThe dimensional changes that the strain of expression resin-coated hard particles 74c and γ represent resin-coated hard particles 74c.

The average diameter of average diameter and resin-coated hard particles 73c of supposing elastic material 72m is basic identical, as shown in Figure 5, the strain of elastic material 72m can be expressed as ε _m=γ/(r _a+ 2s) (formula (1c)).In formula (1c), suppose that the variation of dimensional changes and elastic material 72m of resin-coated hard particles 74c is basic identical, as shown in Figure 5.

Must guarantee to concern σ _m≤σ _cSet up, thereby stress is concentrated among the hard particles 74a in the resin-coated hard particles 74c.According to following formula (1a), σ _b=σ _cSet up, therefore, can will concern σ _m≤σ _cBe expressed as ε _mE _m≤ε _bE _b(formula (1d)).Formula (1b) and (1c) substitution with in the formula (1d) obtain (E _mγ)/(r _a+ 2s)≤(E _bγ)/(2s) (formula (1e)).Formula (1e) is converted, obtain following formula (1), wherein E _m＞E _b

In condition (3), E _bPreferably be equal to or greater than 1GPa; Can prevent that hard particles during rubbing (a) from coming off because have the resin (b) of enough Young's modulus from first friction material; Suitable stress that realization hard particles (a) stands and hard particles (a) are from the suitable overhang of friction surface, and this causes being suppressed at producing in the hard particles (a) surrenders.If E _bLess than 1GPa, then can lose coming off of hard particles (a) prevented that effect and surrender from suppressing effect.Especially, E _bPreferably be not less than 2GPa, most preferably be not less than 3GPa.

In condition (3), E _mPreferably be not less than 1GPa, can obtain suitable stress that hard particles (a) stands and hard particles (a) suitable overhang from friction surface because have the elastic material (m) of enough Young's modulus.Especially, E _mPreferably be not less than 2GPa, most preferably be not less than 3GPa.

The method that is used to calculate average coating thickness for example can relate to, and confirms resin-coated thickness through will from the diameter of hard particles after the resin-coated, deducting before the resin-coated diameter of hard particles.The method that is used to measure the diameter of hard particles before and after the resin-coated can be for example laser diffraction or scattering method (little tracing).

For example, through making an experiment, can measure and calculating elastic modulus E according to defined method among the JIS JIS K 7181 _bAnd E _m

Be used to measure the average diameter r of hard particles (a) _aMethod can with the average diameter r that is used to measure inorganic particulate (f) _fEmployed method is identical.

In condition (4), first friction material and second friction material satisfy following formula (2).

0.2 \leq (\frac{σ_{2}}{σ_{1}}) \cdot (\frac{{\overset{&OverBar;}{C}}_{A}}{C_{a}}) \cdot {(\frac{R_{A}}{r_{a}^{\cdot}})}^{2} \leq 5

Formula (2)

Formula (2) derives by following.The friction centering of embodiment of the present invention 1, mainly in hard particles, produce frictional force.When friction takes place between first friction material and second friction material when, the frictional force F that from second friction material, receives through first friction material ₁Concentrate in the hard particles (a) at the first friction material outmost surface layer place.The composition of hard particles in the outmost surface layer (a) and the said hard particles of covering (a) (that is, the resin (b) and the inorganic particulate (f) of elastic material (m), the said hard particles of coating) must hold out against frictional force F ₁Said first friction material comprises hard particles (a) and above-mentioned covering composition.Therefore, the yield stress on the material of supporting hard particles (a) is the yield stress σ of first friction material ₁Therefore, can be with frictional force F ₁Be expressed as F ₁∝ σ ₁R _a ²C _a(formula (2a)), wherein C _aBe the concentration of hard particles in first friction material (a), and r _aIt is the average diameter of hard particles in first friction material (a).

Similar with the situation of first friction material, can be with the frictional force F that from first friction material, receives through second friction material ₂Be expressed as F ₂∝ σ ₂R _A ²C _A(formula (2b)), wherein C _ABe the concentration of hard particles in second friction material (A), R _ABe the average diameter of hard particles in second friction material (A), and σ ₂It is the yield stress of second friction material.Although because action-reaction law makes F ₁Should equal F ideally ₂, but when classifying contact probability as key factor, through supposing 0.2≤(F ₂/ F ₁)≤5 and obtain formula (2).

Except satisfying formula (2), also requirement of condition (4), σ ₁=10～100MPa, σ ₂=100～800MPa, and C _A=0.1～95 volume %.If the yield stress σ of first friction material ₁Be lower than 10MPa, then can not produce enough frictional force.If σ ₁Value surpass 100MPa, then second friction material can stand excessive wear.Preferably, σ ₁Be not less than 22MPa, more preferably be not less than 24MPa.In addition, σ ₁Preferably be no more than 38MPa, more preferably no more than 36MPa.

If the yield stress σ of second friction material ₂Be lower than 100MPa, then can not produce enough frictional force.If σ ₂Value surpass 800MPa, then first friction material can stand excessive wear.Preferably, σ ₂Be not less than 110MPa, more preferably be not less than 120MPa.In addition, σ ₂Preferably be no more than 790MPa, more preferably no more than 780MPa.

Through based on confirming yield stress, can measure and calculate the yield stress σ of first friction material according to the test of the said method of definition among the JIS K 7181 ₁Yield stress σ with second friction material ₂

If the concentration C of hard particles in second friction material (A) _ABe lower than 0.1 volume %, then can not produce enough frictional force.If C _AValue surpass 95 volume %, then first friction material can stand excessive wear.C _ABe preferably at least 0.15 volume %, more preferably at least 0.2 volume %.In addition, C _APreferably be no more than 92.5 volume %, more preferably no more than 90 volume %.

By condition σ ₁=10～100MPa and σ ₂=100～800MPa can obtain inequality 1≤(σ ₂/ σ ₁)≤80 (formula (2c)).Can access following inequality (2d) according to formula (2c) and formula (2).

0.2 \leq \frac{C_{a}}{C_{A}} {(\frac{r_{a}}{R_{A}})}^{2} \leq 400

Formula (2d)

Fig. 2 is the figure that schematically shows by condition (4) restricted portion, and wherein X-axis is represented (r _a/ R _A) ²And Y-axis is represented (C _a/ C _A).Through curve (C _a/ C _A) (r _a/ R _A) ²=0.2 and curve (C _a/ C _A) (r _a/ R _A) ²=400 delimit by the represented scope of formula (2d).Because C _ASo=0.1～95 volume % are with (C _a/ C _A) upper limit y ₁Be set in y ₁(=C _a/ 0.1 volume %) locate and with lower limit set at y ₂(=C _a/ 95 volume %) locate.Thus, the scope by condition (4) expression is the zone that has the inclination shade among the figure.

Friction centering in embodiment of the present invention 1; Consider from above-mentioned stress distribution mechanism and material design method, in above-mentioned condition (1)～(4), preferred satisfied condition (1) at least; More preferably satisfy condition (1) and (3) at least, most preferably satisfy full terms (1)～(4).

Next the wherein hard particles (a) in first friction material, first friction material is coated with the resin-coated hard particles (c) of resin (b) and the elastic material (m) outside the resin-coated hard particles is elaborated, wherein said elastic material (m) constitutes the matrix of said first friction material.In addition; Next also low and higher than resin (b) host material (M) is elaborated than hard particles (A) to the hard particles (A) in second friction material, second friction material and Mohs hardness, and wherein said hard particles (A) is embedded in the said host material (M).

Be used for the hard particles (a) of first friction material and second friction material and (A) have a high hardness and by processing as the material of the main agents that the friction of friction material is responsible for.The instantiation of this material is for example stupalith.Said stupalith comprises carbide such as silicon carbide, Tungsten carbite, boron carbide, titanium carbide, zirconium carbide, tantalum carbide, cementite or chromium carbide; Oxide such as aluminium oxide, zirconium oxide, titanium dioxide, chromium oxide or silica; Nitride such as silicon nitride, titanium nitride, boron nitride or zirconium nitride; Or boron compound such as titanium boride or FeB.Except the top stupalith of listing, also hard intermetallic compounds such as FeAl can be used as hard particles (a) and hard particles (A).Said hard particles (a) and (A) same material in both materials of listing above can all being.Perhaps, hard particles (a) and (A) can be material different.Likewise, the mixture of two or more different materials in the above-mentioned material can be used as hard particles (a) and hard particles (A).

In order when obtaining excellent frictional force stability and suppressing noise and vibration, to increase frictional force, at least a Mohs hardness preferably is not less than 4.5 in said hard particles (a) and the hard particles (A).When in first friction material and second friction material, all using Mohs hardness to be lower than 4.5 hard particles; Said hard particles has low yield stress; As a result, when first material and the second material both stand stress, be easier in hard particles, surrender.As a result, the wearing and tearing in each friction material self increase, and this can hinder the realization of expectation wear resistance.Especially, Mohs hardness at least a in the above-mentioned hard particles preferably is not less than 4.75, most preferably is not less than 5.

The resin (b) that is used for first friction material is the elastic material with suitable elasticity modulus.Said resin (b) mainly is responsible for fully reducing the overhang of hard particles (a) from friction surface through the distortion during rubbing.Particularly, resin (b) is preferably and is selected from least a in the following non-crystalline resin, and said non-crystalline resin is derived from polyimide, polyamidoimide, polycarbonate (PC), PPO, polyene propyl ester, polysulfones and polyether sulfone.Through selecting suitable non-crystalline resin, obtain hard particles (a) stands during rubbing stress preferably and hard particles (a) overhang preferably, and suppress the surrender of hard particles better from friction surface.Said resin (b) can be the mixture of two or more different materials in the above-mentioned material.

Accomplish the resin-coated hard particles (c) that is used for first friction material through utilizing resin (b) that hard particles (a) is all coated.Through utilizing elastic resin to coat hard particles; It fully reduces the function of hard particles from the overhang of friction surface said resin performance; Make also that simultaneously hard particles demonstrates sufficiently high frictional force, this with do not utilize elastic resin different to the situation that hard particles coats.

Utilize method that elastic resin coats hard particles can for, for example infusion process wherein utilizes elastic resin that hard particles is coated through dipping; The coating method, wherein with the spraying etc. form elastic resin is coated on the hard particles; Wherein that resin-coated and hard particles machinery is kneaded together and become the method for bead; Or wherein the resin-coated hard particles that forms fluid layer and will be heated to the temperature that is equal to or higher than said resin softening point is injected the method for said fluid layer.Can select best method for coating according to the material that reality is used.Especially, method for coating is preferably selected from said method, can under more accurate condition, design by the coating thickness (for example, the average coating thickness in above-mentioned condition (3)) to elastic resin because it makes.

Except resin-coated hard particles (c), also comprise the elastic material (m) outside the resin-coated hard particles according to first friction material of first aspect present invention.Said elastic material also constitutes the matrix of first friction material.

Preferably, elastic material (m) contains at least a elastic material that is selected from phenolic resin, phenol-formaldehyde resin modified, amino resin, furan, unsaturated polyester resin, diallyl phthalate resin, alkyd resin, epoxy resin, thermosetting polyamide imide resin, thermoset polyimide resin and the organic siliconresin.Through selecting suitable elastic materials, acquisition stress preferably that hard particles (a) stands during rubbing and hard particles (a) are from the overhang preferably of friction surface.

Said host material (M) constitutes the matrix of second friction material.The instantiation of said host material (M) for example comprises metallic material such as iron, cobalt, nickel, chromium, titanium, copper, aluminium or has a kind of alloy as main component in these metals; Or the composite material of the composite material of inorganic material such as carbon, carbon and carbon fiber or carbon and pottery.

First friction material according to first aspect present invention can further use basic material.Employed basic material is preferably indeformable material when heating, is specially organic fiber such as aramid fibre, nylon, cellulose etc.; Or inorfil such as Steel Fibre, copper fiber, ceramic fiber, glass fibre, rock wool etc.The ratio of basic material is preferably 5～50 volume % of whole friction materials.

Preferably, said first friction material contains and amounts to resin-coated hard particles (c) and the elastic material (m) be not less than 5 volume %, and resin-coated hard particles (c) drops on the volume ratio of elastic material (m) in 2: 1～1: 50 the scope.Aspect above-mentioned stress distribution mechanism, if the total concentration of resin-coated hard particles (c) and elastic material (m), then may not fully produce frictional force stability and the combined effect that suppresses noise and vibration less than 5 volume %.Make that resin-coated hard particles (c) is 2: 1 a concentration to the volume ratio of elastic material (m) if the concentration of resin-coated hard particles (c) surpasses, then second friction material possibly increase with respect to the wearing and tearing of first friction material.On the other hand, make that resin-coated hard particles (c) is 1: 50 a concentration to the volume ratio of elastic material (m) if the concentration of elastic material (m) surpasses, then frictional force possibly descend.Especially, the total concentration of resin-coated hard particles (c) and elastic material (m) preferably is not less than 6 volume %, and resin-coated hard particles (c) preferably drops on the volume ratio of elastic material (m) in 1: 1～1: 30 the scope.Most preferably, the total concentration of resin-coated hard particles (c) and elastic material (m) is not less than 7 volume %, and resin-coated hard particles (c) drops on the volume ratio of elastic material (m) in 1: 2～1: 10 the scope.

Preferably, the Young's modulus of first friction material is 100～300MPa.If the Young's modulus of first friction material is lower than 100MPa, then the whole Young's modulus of friction material becomes too low.This possibly hinder and be implemented in stress preferably that the hard particles (a) that comprises in first friction material stands and hard particles (a) overhang preferably from friction surface.If the Young's modulus of first friction material surpasses 300MPa, then the whole Young's modulus of first friction material maybe be too high.As a result, the hard particles (a) in first friction material can come off during rubbing.Especially, the Young's modulus of first friction material preferably is not less than 120MPa, most preferably is not less than 140MPa.In addition, the Young's modulus of first friction material preferably is no more than 280MPa, is most preferably not exceeding 260MPa.The method that is used to measure the Young's modulus of first friction material can be identical with the method for the Young's modulus of Young's modulus that is used to measure above-mentioned elastic resin or elastic material.

Preferably, the surface roughness of the friction surface of second friction material is no more than 10 μ m, can damage initial break-in because surface roughness surpasses 10 μ m, and this can cause change in friction force and wearing and tearing to increase again.10 mean roughness (Rz JIS) according to according to JIS JIS B 0601 are confirmed surface roughness.Especially, the surface roughness of the friction surface of second friction material is 9 μ m at the most, is most preferably not exceeding 8 μ m.When the surface roughness of the friction surface of second friction material during, can fully produce above-mentioned effect at least 0.01 μ m.

Use conventional method as using the dry mixed of vertical mixer, horizontal blender etc.; Perhaps wherein in the presence of water or organic solvent, use above-mentioned mixer etc. to carry out wet-mixed, subsequent degassifying using vacuum or heat de-airing mix the material that comprises above-mentioned first friction material to remove the method for desolvating.Use method that the mixture wherein will use above-mentioned mixed method to obtain packs in the heated die and suppress, or the mixture that wherein will use above-mentioned mixed method to obtain be bonded to the method for basic material, can make the friction material shaping.Said friction material can be configured as any desired configuration such as line, rod, plate or sheet.

Use several different methods hard particles (A) to be mixed with the particle and the needed inorganic particulate (F) of host material (M), subsequently the mixture that makes is carried out sintering as using pebble mill etc.; Sintering body is engaged on the friction surface part of structural matrix member through mechanical fasteners or welding like electric welding or laser bonding; Through plasma spraying etc. the material powder that mixes is sprayed on the friction surface of structural matrix member; Perhaps the metallic material (M) that will wherein disperse galvanoplastic to be dispersed with hard particles (A) or hard particles (A) and inorganic particulate (F) through particle is electroplated onto on the friction surface of structural matrix member, can prepare second friction material.Also can use casting method, as long as hard particles is separated out during process of setting.Cast iron can be used as said second friction material, and condition is to alloy composition and casting condition controls so that cementite (cementite) is separated out.

Fig. 3 shows the rub schematic cross-sectional view of right representative instance of the present invention.Friction of the present invention has first friction material 1 and second friction material 2 to 100, makes friction surface 43 adjacency of the friction surface 41 and second friction material 2 of the friction material 1 of winning.Said first friction material 1 has wherein that hard particles (a) 11 is coated with the resin-coated hard particles (c) 13 of resin (b) 12 and the elastic material (m) 14 outside the said particle (c) 13, the matrix that said elastic material (m) 14 constitutes first friction material.Said second friction material 2 has hard particles (A) 21 and host material (M) 24.Preferably, said friction to 100 satisfy at least (A) 21 and host material (M) 24 both.Preferably, said friction to 100 satisfy above-mentioned at least conditions (1) and (3) both.

Fig. 4 A and 4B show that stress applies the schematic cross-sectional view of the right representative instance of the above-mentioned friction in front and back.Fig. 4 A has shown the situation before the right representative instance stress application of friction, i.e. situation before the friction slip.Is to be applied to the factor that the right stress of friction surpasses the yield stress the hard particles from the outstanding hard particles (a) 11 of the friction surface of each friction material with (A) 21 projection 50.Fig. 4 B has shown in the situation after the right representative instance stress application of friction, i.e. situation during friction slip.Shown in figure, resin (b) 12 and the host material (M) 24 that coats hard particles (a) 11 distortion that when stress applies, becomes.As a result, friction has stress distribution mechanism to 100, and when friction stood stress to 100, the excessive stress that gives hard particles (a) 11, (A) 21 was fully absorbed by the distortion of resin (b) 12 or host material (M) 24 thus.This makes hard particles be difficult for standing the above stress of yield stress.And the elastic material in first friction material (m) 14 guarantees that contact surface 15 is on whole friction surface.This provides effective friction on the whole zone between the friction surface.

Friction in above-mentioned representative instance is to have stress distribution mechanism thus; Therefore; When rubbing to stress application; The excessive stress that gives on hard particles (a), (A) is fully absorbed by resin (b) or host material (M); As a result, hard particles (a), (A) are difficult for standing the above stress of yield stress.Therefore, when realizing excellent frictional force stability and suppressing noise and vibration, said friction is to producing high frictional force through hard particles (a), (A).

1 by using the resin (b) coated with hard particles (a) to prepare a resin-coated hard particles, silicon carbide (SiC, Mohs hardness of 9.3, Green? Densic

(GC), produced by Showa Denko KK (Showa ? Denko), Ltd.) as the hard particles (a).The polyamide-imide (hereinafter referred to as PAI, Molykote

(PA-744), by the Dow Corning Toray Co., Ltd. (Dow? Corning? Toray), Ltd.) as the resin (b).In order to utilize resin (b) that hard particles (a) is coated, SiC is mixed with PAI in being dissolved in solvent, make PAI and SiC (solid in the solvent) be equivalent proportion (1: 1).Thereafter, evaporating solvent is to form the resin-coated hard particles.Use the laser diffraction granularity ANALYZER that the granularity of SiC before and after the resin-coated is measured.Then, according to the thickness (s) of the difference calculating resin-coated of the average diameter of SiC before the average diameter of SiC after the resin-coated and the resin-coated.

2. it is right to create friction

Through the material that shows with ratio (volume %) that provides in the following table 1 is mixed first friction material of making according to the embodiment of the invention (brake rim).Term in the table 1 " SiC (PAI coats) " is meant the silicon carbide of the resin-coated that in the preparation of above-mentioned resin-coated hard particles, obtains.Use above-mentioned laser diffraction granularity ANALYZER to measure the granularity of listing in the following table 1.In the material of in table 1, listing, the Mohs hardness of SiC (hard particles (a)) is 9.3, and the average diameter of the SiC of resin-coated is 26 μ m.The Mohs hardness of mica (inorganic particulate (f), average diameter are 15 μ m) is 2.5～3.0.The Mohs hardness of barium sulphate (inorganic particulate (f), average diameter are 10 μ m) is 3.5.Therefore, embodiment's first friction material satisfy condition (1).The details of production method is following.At first, in vertical mixer, various raw materials were evenly mixed 5 minutes, thereby obtain the friction material raw mix.In thermoforming step subsequently, the friction material raw mix is enclosed in 150 ℃ of following heated mold, and at 200kg/cm ²Pressed 10 minutes.At 200 ℃ down solidify 2 hour, thereby obtain first friction material thereafter.Make second friction material (rotor) according to following method.The Tungsten carbite (WC, Mohs hardness is 9) that will have 3 μ m average diameters is used as host material (M) with cobalt (Mohs hardness is 5.5) simultaneously as hard particles (A).Use cobalt as tackiness agent, obtain second friction material through plasma spraying WC on cast-iron rotor.WC concentration in sprayfused coating is 90 volume %.Said first friction material (brake rim) and second friction material (rotor) combination is right with the friction that obtains embodiment.

Through the material of listing in the following table 1 being mixed first friction material (brake rim) for preparing comparative example with the ratio (volume %) that provides in the comparative example hurdle in the table 1.Table 1, the term "SiC (uncoated)" means the use of any resin-coated and not used as a silicon carbide (SiC, Mohs hardness of 9.3, Green? Densic

(GC), manufactured by the Showa Denko ).Use above-mentioned laser diffraction granularity ANALYZER to measure the granularity of listing in the following table 1.In the material of in following table 1, listing, SiC does not have defined resin-coated, therefore, and first friction material of this comparative example do not satisfy condition (1).The details of production method is following.At first, in vertical mixer, various raw materials were evenly mixed 5 minutes, thereby obtain the friction material raw mix.In thermoforming step subsequently, the friction material raw mix is enclosed in 150 ℃ of following heated mold, and at 200kg/cm ²Pressed 10 minutes.At 200 ℃ down solidify 2 hour, thereby obtain first friction material thereafter.Use with the identical method of method of friction centering second friction material of making embodiment and make second friction material (rotor).Said first friction material (brake rim) and second friction material (rotor) combination is right with the friction that obtains comparative example.

Table 1

3. the measurement and the evaluation of the right frictional behaviour that rubs

Under the temperature of 100 ℃ or 300 ℃,, make it each other against sliding and continuing 1 hour, brake 0m/s from 1m/s subsequently with the speed of 1m/s at the load held of the 200N sample right according to the friction of embodiment and comparative example.The wear extent that friction factor during table 2 pair friction factor (μ), the braking changes before and after (Δ μ) and the braking compares.

Table 2

	Embodiment	Comparative example
			Friction factor (μ)/100 ℃	0.65	0.65
Friction factor (μ)/300 ℃	0.65	0.65
			Δμ/100℃	0.02	0.05
Δμ/300℃	0.03	0.06
			Wear extent/100 ℃	0.1mm	0.1mm
Wear extent/300 ℃	0.3mm	0.3mm

As shown in table 2, under 100 ℃ and 300 ℃ of two temperature, all identical with wear extent at the friction centering coefficientoffriction of embodiment and comparative example.By contrast, the friction centering friction factor changes delta mu in embodiment is littler.The result that above-mentioned frictional behaviour is measured shows, especially, with the routine friction of do not satisfy condition (1) to comparing, the embodiment of the invention friction of satisfy condition (1) is to having more excellent frictional force stability.

4. friction is to the measurement and the evaluation of squeal

Friction for embodiment and comparative example is right, to during cruising in the simcity that the right automobile that respectively rubs is installed (at 40km/ hour speed, 0.1～1.5m/s ²The temperature of deceleration and 50～150 ℃ under carry out 100 braking circulations) squeal frequency and the volume of said squeal measure.The number of times of table 3 pair squeal and volume thereof have carried out relatively summing up.

Table 3

	Embodiment	Comparative example
			The squeal frequency	40 times	100 times
The squeal volume	In-low	High-in

As shown in table 3, with the friction of comparative example to comparing, embodiment's friction is to having sent the squeal and the squeal of amount of bass more still less.Measurement result about the frictional behaviour of squeal shows, with the routine friction of do not satisfy condition (1) to comparing, the friction of the embodiment of the invention of satisfy condition (1) is to suppressing the braking squeal to a greater extent.

Claims

One kind to produce the friction of frictional force through mutual friction slip right, said friction is to comprising:

First friction material, said first friction material contain first hard particles and Mohs hardness than the low resin of said first hard particles, and wherein said resin covers the whole surface of said first hard particles; With

Second friction material; Said second friction material contains second hard particles and Mohs hardness is lower than said second hard particles and Mohs hardness is higher than said resin metallic material or inorganic material; Wherein said metallic material or inorganic material constitute the matrix of said second friction material, and said second hard particles is embedded in the matrix of said second friction material.
2. friction as claimed in claim 1 is right; Wherein said first friction material also comprises the elastic material of the matrix that constitutes said first friction material, and wherein said first hard particles is embedded in the matrix of said first friction material by the resin-coated hard particles of said resin-coated.
3. friction as claimed in claim 2 is right, and wherein said friction is to satisfying at least one in following four conditions, wherein

If said first friction material also contains Mohs hardness first inorganic particulate lower than said first hard particles; And the average diameter of said resin-coated hard particles is not less than 0.2 with respect to first ratio of the average diameter of said first inorganic particulate, then satisfies first condition;

If said second friction material also contains Mohs hardness second inorganic particulate lower than said second hard particles; And the average diameter of said second hard particles is not less than 0.2 with respect to second ratio of the average diameter of said second inorganic particulate, then satisfies second condition;

If said first friction material satisfies following formula (1), then satisfy the 3rd condition:

$s \leq \frac{r_{a} \cdot E_{b}}{2 (E_{m} - E_{b})}$ Formula (1)

Wherein s is the average coating thickness of said resin on said resin-coated hard particles, E _bBe the Young's modulus of said resin, E _mBe the Young's modulus of said elastic material, and r _aBe the average diameter of said first hard particles, and E _m＞E _bAnd

If said first friction material and said second friction material satisfy following formula (2), then satisfy the 4th condition:

$0.2 \leq (\frac{σ_{2}}{σ_{1}}) \cdot (\frac{{\overset{&OverBar;}{C}}_{A}}{C_{a}}) \cdot {(\frac{R_{A}}{r_{a}^{\cdot}})}^{2} \leq 5$ Formula (2)

C wherein _aBe the concentration (volume %) of first hard particles described in said first friction material, C _ABe the concentration (volume %) of second hard particles described in said second friction material, r _aBe the average diameter of first hard particles described in said first friction material, R _ABe the average diameter of second hard particles described in said second friction material, σ ₁Be the yield stress of said first friction material, and σ ₂Be the yield stress of said second friction material, and σ ₁=10～100MPa, σ ₂=100～800MPa and C _A=0.1～95 volume %.
4. friction as claimed in claim 3 is right, and wherein said friction is to satisfying all said first to fourth conditions.
5. right like each described friction in the claim 1～4, at least a in wherein said first hard particles and said second hard particles has at least 4.5 Mohs hardness.
6. right like each described friction in the claim 3～5, wherein said friction is to satisfying said the 3rd condition, and the Young's modulus of said resin is not less than 1GPa.
7. right like each described friction in the claim 1～6, wherein said resin is at least a non-crystalline resin that is selected from polyimide, polyamidoimide, polycarbonate (PC), PPO, polyene propyl ester, polysulfones and the polyether sulfone.
8. right like each described friction in the claim 3～7; Wherein said friction is to satisfying at least one condition in said first condition and the said second condition, and at least a in said first inorganic particulate and said second inorganic particulate has and be no more than 4 Mohs hardness.
9. right like each described friction in the claim 3～8, wherein said friction is to satisfying said the 3rd condition, and the Young's modulus of said elastic material is 1GPa at least.
10. right like each described friction in the claim 2～9, wherein said elastic material contains at least a resin that is selected from phenolic resin, phenol-formaldehyde resin modified, amino resin, furan, unsaturated polyester resin, diallyl phthalate resin, alkyd resin, epoxy resin, thermosetting polyamide imide resin, thermoset polyimide resin and the organic siliconresin.
11. right like each described friction in the claim 3～10, wherein said friction is to satisfying at least one condition in said first condition and the said second condition, and in said first ratio and said second ratio at least one is at least 0.3.
12. friction as claimed in claim 11 is right, wherein said friction is to satisfying said first condition and said second condition simultaneously, and said first ratio and said second ratio all are at least 0.3.
13. it is right like each described friction in the claim 2～12; Wherein the concentration at resin-coated hard particles described in said first friction material and said elastic material is at least 5 volume %, and said resin-coated hard particles is 2: 1～1: 50 to the volume ratio scope of said elastic material.
14. right like each described friction in the claim 1～13, the Young's modulus of wherein said first friction material (1) is 100～300MPa.
15. right like each described friction in the claim 1～14, the surface roughness of the friction surface of wherein said second friction material is no more than 10 μ m.