Improved Anti-noise SHIM and further improved Anti-noise SHIM and its production method

Abstract

It is described an anti-noise shim 100 comprising at least a damping material layer comprising fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers, a filler and a binder, and anti-noise shim (200) or (300) comprising structurally discontinuous or inhomogeneous support layer in the form of a perforated metal foil or made of fiber, respectively, said support layer embedded / sandwiched / inserted between two damping material layers, equal or different to each other, coupled and linked to each other and to the support layer by chemical binder and / or by applying pressure and / or temperature, each damping material layer comprising fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers, a filler and a binder.

Description

[0001] IMPROVED ANTI-NOISE SHIM AND FURTHER IMPROVED ANTI-NOISE

[0002] SHIM AND ITS PRODUCTION METHOD

[0003] ★ ★ ★ ★

[0004] Technical field

[0005] The present invention relates to an improved anti-noise shim, more in detail the invention relates to an improved antinoise shim comprising at least a damping material layer, more preferably comprising structurally discontinuous or inhomogeneous support layer, said support layer selected from the group comprising a perforated metal foil support layer or support layer made of fibers , continuous or discontinuous , long, medium or short fibers , organic or inorganic fibers , with different structural options : fibers distributed randomly to form a compact but inhomogeneous support layer, fibers in the form of a woven "mesh" support layer, fibers arranged in a network wherein the fiber are welded together at the overlapping points to give the network structure support layer, said support layer embedded / sandwiched / inserted between two damping material layers , equal or different to each other, coupled and linked to each other by chemical binder and / or by applying pressure and / or temperature .

[0006] Background

[0007] Shims are widely used in automotive industry as a measure to reduce noise, vibration and harshness (NVH) . This makes the use of shims especially interesting for the brake system, where shims are applied to the brake pads to reduce NVH during a braking event .

[0008] A typical shim is a functional multilayer compound . The number of layers , their thickness as well as the chemical composition of each layer varies between the numerous types of shims available to the market . The composition, thickness and design of a multilayered shim significantly influences its NVH relevant properties .

[0009] Typically, a shim is used for dampening reasons . The shim is bonded to the backplate of the brake pad by an adhesive layer . This is essential to maximize the dampening effects of the shim . Due to its excellent dampening properties as well as its elasticity different kind of rubbers may be used .

[0010] Further type of shim comprises a support metal layer which typically serves both as a carrier for the rubber as well as adding strength to the product in the XY-plane . Also, different types of support metal layers are used depending on the requirements of the target application and cost requirements ( see the Patent no . 102020000011902 granted in the name of the Applicant ) .

[0011] In order to improve the performance of the anti-noise shim already available the Applicant has developed a new cost competitive anti-noise shim with improved properties comparable to higher quality higher price already available on the market .

[0012] Summary

[0013] The present invention deals with a new anti-noise shim which represents a further improvement of the anti-noise shim already available .

[0014] This is achieved by the anti-noise shim comprising at least a damping material layer comprising fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers , a filler and a binder, more preferably further comprising structurally discontinuous or inhomogeneous support layer, said support layer selected from the group comprising :

[0015] - a perforated metal foil support layer or

[0016] - support layer made of fibers , continuous or discontinuous , long, medium or short fibers , organic or inorganic fibers , with different structural options :

[0017] • fibers randomly distributed to form a compact but inhomogeneous support layer,

[0018] • fibers in the form of a woven "mesh" support layer,

[0019] • fibers arranged in a network wherein the fiber are welded together at the overlapping points to give the network structure support layer, said support layer embedded / sandwiched / inserted between two damping material layers , equal or different to each other, coupled and linked to each other and to the support layer by chemical binder and / or by applying pressure and / or temperature, and related methods for the production thereof as defined in the enclosed independent claims .

[0020] Brief description of the drawings

[0021] Figs . 1 shows the structurally discontinuous or inhomogeneous support layer according to the present invention wherein the fibers are distributed randomly to form a compact but inhomogeneous support layer .

[0022] Fig . 2a and 2b show the structurally discontinuous or inhomogeneous support layer according to the present invention wherein the fibers are in the form of a woven "mesh" support layer .

[0023] Fig . 3 shows the structurally discontinuous or inhomogeneous support layer according to the present invention wherein the fibers arranged in a network, with meshes of different sizes (w) , always the same or variable in the same structure, with the fibers having the same diameter (0) or even different diameters , are welded together at the overlapping points to give the network structure forming the support layer . Figs . 4a to 4b show the structurally discontinuous or inhomogeneous support layer according to the present invention in the form of a perforated metal foil .

[0024] Detailed description of the invention

[0025] The applicant surprisingly and unexpectedly developed a new anti-noise shim 100 comprising at least a damping material layer comprising fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers , a filler and a binder .

[0026] As a further preferred embodiment of the present invention, the Applicant surprisingly and unexpectedly developed a new anti-noise shim 200 comprising structurally discontinuous or inhomogeneous support layer in the form of a perforated metal foil, preferably wherein the perforated area is at least 30% , more preferably at least 50% of the entire surface of the foil, said support layer embedded / sandwiched / inserted between two damping material layers , equal or different to each other, coupled and linked to each other and to the support layer by chemical binder and / or by applying pressure and / or temperature, each damping material layer comprising fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers , a filler and a binder .

[0027] As a further preferred embodiment of the present invention, the Applicant surprisingly and unexpectedly developed a new anti-noise shim 300 comprising structurally discontinuous or inhomogeneous support layer made of fiber, such as

[0028] • fibers randomly distributed to form a compact but inhomogeneous support layer,

[0029] • fibers in the form of a woven "mesh" support layer,

[0030] • fibers arranged in a network wherein the fiber are welded together at the overlapping points to give the network structure support layer, said support layer embedded / sandwiched / inserted between two damping material layers , equal or different to each other, coupled and linked to each other and to the support layer by chemical binder and / or by applying pressure and / or temperature, each damping material layer comprising fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers , a filler and a binder .

[0031] According to one embodiment , the binder is an elastomeric binder, but it may also be a non-elastomeric resin type binder . Compared to conventional rubber materials , the fibers make the material stronger and less elastic in the plane without considerably affecting the compression characteristics in the normal direction . Moreover, the fibers and the fillers reduce the amount of elastomeric binder in the layer, thereby making the layer less expensive . According to one embodiment, the fibers content in the damping material layer is not less than 5%, or 10%, or 14%, and not more than 23% or 30% by weight. However, for some applications the fibers content may be higher than 30%, such as up to 50% or up to 80% or even up to 95 %.

[0032] The fibers are selected from organic fibers depending on the specific application. Examples of organic natural fibers include: cellulose fibers, cotton linters fibers (fibers coming from plants, in general) ; examples of organic artificial or synthetic fibers are: aromatic polyamide fibers, polyamide fibers other than aromatic polyamide fibers, polyolefin fibers, polyester fibers, polyacrylonitrile fibers, polyvinyl alcohol fibers, polyvinylchloride fibers, polyurea fibers, polyurethane fibers, polyfluorocarbon fibers, phenol fibers, or the like. According to one embodiment, the fibers comprise aromatic polyamide fibers. More preferably the fibers are selected from inorganic fiber such as carbon fibers, glass fiber, ceramic fiber, rock wool, mineral wool, fused quartz fiber, chemical processed high silica fiber, fused alumina silicate fiber, alumina continuous fiber, stabilized zirconia fiber, boron nitride fiber, alkali titanate fiber, whiskers, boron fiber, wollastonite, basalt fiber, aramid fiber. The filler may be an inorganic filler such as clay, ash, talc, barium sulfate, sodium bicarbonate, graphite, lead sulfate, tripoli, wollastonite, rubber crumbs, or an organic filler. The binder may be an elastomeric material of rubber type such as styrene-butadiene rubber ( SBR) , acrylonitrilebutadiene rubber (nitrile-butadiene rubber, NBR) , isoprene rubber ( IR) , chloroprene rubber (CR) , butadiene rubber (BR) , isobutylene-isoprene rubber ( HR) , ethylene propylene rubber (EPM) , fluoro rubber (FPM) , silicone rubber ( Si ) , chlorosulfonated polyethylene (CSM) , ethylene-vinylacetate copolymers (EVA) , chlorinated polyethylene (CPE ) , chloro- isobutane-isoprene rubber (CUR) , epichlorohydrin rubber (ECO) , nitrile isoprene rubber (NIR) or the like . Elastomers other than rubbers may also be used . According to alternative embodiments the binder is a resin type material such as a rubber modified phenolic resin, a phenolic resin, an epoxy resin or the like .

[0033] In one embodiment of the present invention the structurally discontinuous or inhomogeneous support layer is made of fiber, continuous or discontinuous , long, medium or short fibers , organic or inorganic fibers , such as carbon fiber, metal fiber, glass fiber, polymeric fiber providing to the support layer with different structural options : fibers distributed randomly to form a compact but inhomogeneous support layer (example fig . 1 ) , fibers in the form of a woven "mesh" support layer (example fig . 2a and fig . 2b) , fibers arranged in a network (example fig . 3 ) , with meshes of different sizes (w) , always the same or variable in the same structure, with the fibers having the same diameter (0) or even different diameters wherein the fiber are welded together at the overlapping points to give the network structure forming the support layer .

[0034] As a further embodiment , the structurally discontinuous or inhomogeneous support layer according to the present invention is in the form of a perforated metal foil (example fig . 4a and fig . 4b) , preferably wherein the perforated area is at least 30% , more preferably at least 50% of the entire surface of the foil .

[0035] Preferably the thickness of the support layer made of the metal foil is not higher than 1000 pm, preferably not higher than 400-500 pm, more preferably not higher than 250 pm .

[0036] Preferably the thickness of the support layer made of fibers randomly distributed to form a compact but inhomogeneous support layer is not higher than 1000 pm, preferably not higher than 400-500 pm, more preferably not higher than 250 pm .

[0037] Preferably the thickness of the support layer made of fibers in the form of a woven "mesh" support layer is not higher thanl O O O pm, preferably not higher than 400-500 pm, more preferably not higher than 250 pm .

[0038] More preferably, as a further embodiment of the damping material layer according to the present invention, said damping material layer comprises at least a filler, an organic fiber, more preferably a cellulose fiber, and a binder comprising NBR and / or SBR, wherein the filler is present in an amount between 30 and 70% by weight , preferably between 45 and 55% by weight , the organic fiber, more preferably cellulose fiber, is present in an amount between 15 and 30% by weight , preferably between 20 and 25% by weight , the binder comprising NBR and / or SBR is present in an amount between 15 and 30% by weight , preferably between 20 and 25% by weight , said percentage being based on 100 parts by weight of the combination of the filler, the organic fiber and the binder selected from NBR and / or SBR .

[0039] Preferably, when both NBR and SBR are present , preferably they are present with a relative rate of percentage by weight NBR / SBR from 35 / 65 to 65 / 35 being 100% by weight the sum of NBR and SBR .

[0040] The technical advantages due to the damping material layer according to the present invention, combined with the cost- saved advantages in view of the reduction of the amount of the more expensive material, are that the damping effect is achieved by the fiber material ' s ability to generate inner friction work and rubber deformation . Whereas rubber generally causes damping by only deformation , the majority of inner work can be expressed by the friction between the single fiber strains when deforming the bundle . Again, excitation energy is converted into heat , thus increasing the dampening effect . Since the damping material layer, according to the present invention, uses both fibers and rubber, the resulting damping is a combination of both effects .

[0041] In view of the above-mentioned combined advantages , the Applicant developed a further anti-noise shim technology comprising the coupling of the damping material layer according to the present invention with a support layer structurally discontinuous or inhomogeneous , selected from the group comprising :

[0042] - a perforated metal foil support layer or

[0043] - support layer made of fibers , continuous or discontinuous , long, medium or short fibers , organic or inorganic fibers , with different structural options :

[0044] • fibers randomly distributed to form a compact but inhomogeneous support layer,

[0045] • fibers in the form of a woven "mesh" support layer,

[0046] • fibers arranged in a network wherein the fiber are welded together at the overlapping points to give the network structure support layer, where, in all said support layers , the layer of damping material grips the support layer due to the fact that said support layer has a discontinuous or inhomogeneous structure having holes , meshes , or having an irregular texture such as randomly distributed fibers or fibers to form a woven mesh . The technical advantages due to the anti-noise shim comprising a support layer made of fiber with the different structural options embedded in two damping material layers according to the present invention are that said support layer adds strength to the anti-noise shim being solicited in radial (XY) direction by the piston .

[0047] The technical advantages due to the anti-noise shim comprising a support layer made of a perforated metal foil embedded in two damping material layers according to the present invention are that said support layer absorbs vibration waves better than solid metal ( i . e . , a foil of whole metal ) .

[0048] It is a further object of the present invention the method of production of the anti-noise shim 100 or 200 or 300 comprising damping material layer according to any of the preferred embodiments thereof of the present invention wherein the damping material layer provided is obtained according to the method of production of the damping material layer as follows : a) preparation of the damping material slurry wherein organic fibers , mechanically dispersed with the addition of water, in a pulper, and subsequently def ibrillated (" refined" ) , are initially mixed with the inorganic and / or synthetic fillers and fibers in water, being subsequently added with binder and vulcanizer; b) preparation of the damping material layer wherein : bl ) the damping material slurry is loaded by a head box into a flow spreader with the following steps i ) Foudrinier abel section ii) Press section iii ) Dryer section iv) Calendar stack section v) Reel section to obtain a semi-finished damping material layer, b2 ) semi-finished damping material layer is calendared b3 ) the calendared semi-finished damping material layer is vulcanized to obtain the damping material layer .

[0049] It is a further object of the present invention the method of production of the anti-noise shim 200 comprising structurally discontinuous or inhomogeneous support layer in the form of a perforated metal foil combined with damping material layer according to any of the preferred embodiments thereof of the present invention, said method comprising :

[0050] - provide a perforated metal foil according to the present invention,

[0051] - provide two damping material layers , equal or different to each other, according to the present invention, - embedding / sandwiching / inserting the perforated metal foil between the two damping material layer which are coupled and linked to each other and to the perforated metal foil by chemical binder and / or by applying pressure and / or temperature .

[0052] It is a further object of the present invention the method of production of the anti-noise shim 300 comprising structurally discontinuous or inhomogeneous support layer in the form of support layer made of fibers selected from the group comprising :

[0053] • - fibers randomly distributed to form a compact but inhomogeneous support layer,

[0054] • fibers in the form of a woven "mesh" support layer,

[0055] • fibers arranged in a network wherein the fiber are welded together at the overlapping points to give the network structure support layer combined with damping material layer according to any of the preferred embodiments thereof of the present invention, said method comprising :

[0056] - provide a support layer made of fiber according to the present invention,

[0057] - provide two damping material layers , equal or different to each other, according to the present invention, embedding / sandwiching / inserting the support layer made of fibers between the two damping material layer which are coupled and linked to each other and to the support layer made of fibers by chemical binder and / or by applying pressure and / or temperature .

[0058] There is also provided a disc brake arrangement comprising an anti-noise shim according to anyone of the above embodiments between the calliper and the brake pad, and the disc brake may be arranged in a suitable vehicle -such as a car, truck, train, motorbike, bicycle etc .

[0059] In order to fully utilize the anti-noise shims according to the invention, there is further provided a method to prevent noise in a disc brake, comprising the step of arranging an anti-noise shim according to anyone of the above embodiments between the calliper and the brake pad .

Claims

CLAIMS1 . Anti-noise shim ( 100 ) comprising at least a damping material layer comprising fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers , a filler and a binder .2 . Anti-noise shim ( 200 ) or ( 300 ) comprising structurally discontinuous or inhomogeneous support layer in the form of a perforated metal foil or made of fiber, respectively, said support layer embedded / sandwiched / inserted between two damping material layers , equal or different to each other, coupled and linked to each other and to the support layer by chemical binder and / or by applying pressure and / or temperature, each damping material layer comprising fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers , a filler and a binder .3 . Anti-noise shim ( 200 ) according to claim 2 , wherein the perforated area of the perforated metal foil is at least 30% , more preferably at least 50% of the entire surface of the foil .4 . Anti-noise shim ( 300 ) according to claim 2 wherein the discontinuous or inhomogeneous support layer made of fiber is selected from the group comprising :• fibers randomly distributed to form a compact but inhomogeneous support layer,• fibers in the form of a woven "mesh" support layer,• fibers arranged in a network wherein the fiber are welded together at the overlapping points to give the network structure support layer .5 . Anti-noise shim according any one of the preceding claims wherein the damping material layer comprises at least a filler, an organic fiber, more preferably a cellulose fiber, and a binder comprising NBR and / or SBR, wherein the filler is present in an amount between 30 and 70% by weight , preferably between 45 and 55% by weight , the organic fiber, more preferably cellulose fiber, is present in an amount between 15 and 30% by weight , preferably between 20 and 25% by weight , the binder comprising NBR and / or SBR is present in an amount between 15 and 30% by weight , preferably between 20 and 25% by weight , said percentage being based on 100 parts by weight of the combination of the filler, the organic fiber and the binder selected from NBR and / or SBR .6 . Anti-noise shim according to any one of the preceding claims wherein the fiber content by weight in the damping material layer is 95% or less , preferably 50% or less, more preferably 30% or less , and even more preferably 23% or less .7 . Anti-noise shim according to any one of the preceding claims wherein damping material layer comprises fibers selected from the group comprising synthetic organic fibers , such as cellulose fibers cotton linters fibers ( fibers comingfrom plants , in general ) aromatic polyamide fibers, aramidic fibers , polyamide fibers other than aromatic polyamide fibers , polyolefine fibers , polyester fibers , polyacrylonitrile fibers , polyvinyl alcohol fibers , polyvinylchloride fibers , polyurea fibers , polyurethane fibers , polyfluorocarbon fibers , phenol fibers , and / or inorganic fibers such as , carbon fibers , glass fiber, ceramic fiber, rock wool, mineral wool, fused quartz fiber, chemical processed high silica fiber, fused alumina silicate fiber, alumina continuous fiber, stabilized zirconia fiber, boron nitride fiber, alkali titanate fiber, whiskers , boron fiber, wollastonite, basalt fiber, aramid fiber .8 . Anti-noise shim according to any one of the preceding claims wherein the filler material comprises an inorganic filler material such as clay, ash, talc, barium sulfate, sodium bicarbonate, graphite, lead sulfate, tripoli, wollastonite, rubber crumbs or an organic filler .9 . Anti-noise shim according to any one of the preceding claims wherein the binder material comprises an elastomeric material of latex / rubber type such as styrene-butadiene rubber ( SBR) , acrylonitrile-butadiene rubber (nitrile rubber, NBR) , isoprene rubber ( IR) , chloroprene rubber (CR) , butadiene rubber (BR) , isobutylene-isoprene rubber ( HR) , ethylene propylene rubber (EPM) , fluoro rubber (FPM) , silicone rubber( Si ) chloro sulfonated polyethylene (CSM) ethylene- vinylacetate copolymers (EVA) , chlorinated polyethylene (CPE ) chloro-isobutane-isoprene rubber (CUR) , epichlorohydrin rubber (ECO) , nitrile isoprene rubber (NIR) or the like, or the binder material comprises a resin type material such as a rubber modified phenolic resin, a phenolic resin, an epoxy resin or the like .10 . Anti-noise brake shim comprising an anti-noise shim according to any one of claims 1 to 9 .11 . Method to prevent noise in a disc brake, comprising the step of arranging the anti-noise brake shim according to claim 10 between the brake calliper and the brake pad .12 . Disc brake arrangement comprising the anti-noise brake shim according to claim 10 between the calliper and brake pad .13 . Vehicle comprising a disc brake arrangement according to claim 12 .14 . Method of production of the anti-noise shim ( 100 ) or ( 200 ) or ( 300 ) according to any one of the claim 1-9, wherein the damping material layer provided is obtained according to the method of production of the damping material layer as follows : a) preparation of the damping material slurry wherein organic fibers , mechanically dispersed with the addition of water, in a pulper, and subsequently def ibrillated("refined") , are initially mixed with the inorganic and / or synthetic fillers and fibers in water, being subsequently added with binder and vulcanizer; b) preparation of the damping material layer wherein: bl) the damping material slurry is loaded by a head box into a flow spreader with the following steps i) Foudrinier abel section ii) Press section iii) Dryer section iv) Calendar stack section v) Reel section to obtain a semi-finished damping material layer, b2) semi-finished damping material layer is calendared b3) the calendared semi-finished damping material layer is vulcanized to obtain the damping material layer.

15. Method of production of the anti-noise shim (200) according to any of claim 2, 3, 5 - 9, said method comprising:- provide a perforated metal foil according to claim 2 or 3,- provide two damping material layers, equal or different to each other, according to claim 2, 5 - 9,embedding / sandwiching / inserting the perforated metal foil between the two damping material layer which are coupled and linked to each other and to the perforated metal foil by chemical binder and / or by applying pressure and / or temperature .16 . Method of production of the anti-noise shim ( 300 ) according to any of claim 2 , 4 , 5 - 9, said method comprising :- provide a support layer made of fiber according to claim 2 or , - provide two damping material layers , equal or different to each other, according to claim 2 , 5 - 9,- embedding / sandwiching / inserting the support layer made of fibers between the two damping material layer which are coupled and linked to each other and to the support layer made of fibers by chemical binder and / or by applying pressure and / or temperature .

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