KR20040111349A - Composite friction elements and pultrusion method of making - Google Patents

Abstract

The composite friction unit of the three-dimensional composite body is formed of a substantially uniform array of predominantly glass strands of primary reinforcing fibers in a matrix of phenolic resin material, and the reinforcing fibers in the form of fabrics distributed over the body have a predetermined size and shape. And a friction unit having fibers of uniform distribution and alignment throughout. Alternative friction units include laminates with substantially rigid backings that are simultaneously drawn through a forming die forming the unit. The unit is manufactured in a drawing process in which the reinforcing fibers and matrix are pulled through the forming die.

Description

COMPOSITE FRICTION ELEMENTS AND PULTRUSION METHOD OF MAKING}

A friction brake is basically a pair of friction members that are rotational members and stop members that are coupled to produce a frictional force that is measured as a braking torque for slowing or stopping the rotating element. The brake is preferably designed such that the braking torque is somewhat proportional to the input used to engage the elements and the energy of the rotating member is dissipated in the form of heat. Unfortunately, pressure is not the only factor that affects the frictional response of the brake element. The frictional effect between the friction elements causes the frictional force and braking torque to change with the coupling pressure, speed and temperature, and to rely on the laminated interfacial film for stabilization. Nevertheless, the brake is preferably designed such that the braking torque is suitably proportional to the input used to couple the elements. The braking energy is dissipated in the form of heat through the brake element. For this reason they must be able to withstand considerable heat in most applications.

The rotating element of the brake system is generally a disc or drum made of metal, such as hardened steel, and the stop element is usually a composite pad or shoe lining that is movable to engage with the rotating element. The composite element is designed to wear without excessive wear of the metal disk or drum. The material forming the composite element is a principle unpredictable variable that has the greatest impact on the performance characteristics of the brake system. Preferred materials of the composite element should be safe to use, relatively inexpensive, and have good friction, wear and thermal performance properties. This includes good fade resistance, or the ability to maintain good (preferably substantially uniform) braking by heat generation.

A friction clutch is a pair of friction elements similar to the brakes in some respects and basically designed to selectively couple the rotational drive element to the drive element to guide the drive element at a speed for rotation by the drive element. A clutch element, one driven and one driven and rotating, is engaged to generate a frictional force drive torque for accelerating the slow moving or stationary element by the rotational drive element.

Until recently, the main material used in the production of friction pads and disks for brakes, clutches, and the like is asbestos. These pads are manufactured by a molding process in which each unit is formed of a composite of asbestos fibers optionally oriented in a bonding matrix placed under pressure in a mold cavity. However, asbestos is carcinogenic and it has been found that this use releases asbestos potentially harmful to the environment. As a result, some developed countries have banned the use of asbestos friction materials, and other countries, including the United States, are required to phase out the use of asbestos over the next few years. Therefore, there is an urgent need for a safe and effective friction material and an economical method of producing the material with a suitable friction unit.

In recent years extensive research has been conducted to find suitable environmentally safe materials and composites with desirable wear, heat and other characteristics to function as a substitute for asbestos as a friction element for brakes and clutches. These studies have been frustrated by a number of various related parameters, including the range of requirements that match between brakes and clutches as well as different types of brakes and different types of clutches. For example, different sized vehicles require different sized friction pads for both the brake and clutch, and often have other variables including higher operating force and temperature. Brake pads used for rotating discs have different conditions than shoes used for brake drums. In addition, clutches used in automatic transmissions have different conditions than clutches used in manual or stick transmissions.

Attempts to meet the demand for long life, high friction, heat resistant friction materials include proposals to utilize various chopped fibers molded into bonding matrices such as resins. The friction unit is conventionally formed by a molding process with fibers and other components disposed in a binder such as dry powder resin cured under heat and pressure and optionally oriented or placed or cured in a liquid resin in a mold. Examples of these composites and preparation methods are described in US Pat. No. 4,119,591, issued October 10, 1978 to Aldrich, US Pat. No. 4,259,397, issued March 31, 1981 to Saito et al. And US Pat. No. 4,432,922, issued February 21, 1984 to Kaufman et al.

However, friction units produced by this method are expensive to manufacture and are not satisfactory due to the lack of uniformity of performance and durability. For example, units from the same batch may vary by as much as 35% in performance characteristics. The nonuniformity of the results was found to be mainly caused by the nonuniformity of the distribution and orientation of the fibers and other components in the matrix. This not only leads to expensive inspection and quality control problems, but also to maintenance problems, sometimes even dangerous situations. For example, pads that match performance at initial installation may change over their service life.

Over the past years, Applicants have developed a wide range of improvements in the drawing method of manufacturing composites and structures as well as composite friction elements for brakes and clutches. Many of these improvements include U.S. Patent 5,156,787, entitled "PULTRUSION METHOD OF MAKING BRAKE LINING", U.S. Patent 5,462,620, named "CONTINUOUS PULTRUSION METHOD OF MAKING FRICTION UNITS," and "UNIFORM". US Patent No. 5,495,922, which is "CompOSITE FRICTION UNITS", and US Patent No. 5,690,770, which is named "PULTRUSION METHOD OF MAKING COMPOSITE FRICTION UNITS." However, Applicants' continuing studies to complete these composites, structures and methods indicate that further improvements in both composites and manufacturing methods are desirable and have been developed by Applicants. For example, improved mechanical performance, composites and structures have been developed, as well as methods for making draws.

Now, further improvements are needed for composites, structures and manufacturing methods.

Accordingly, there is a need for improved composites, structures, and fabrication methods that can be used to overcome conventional and other problems.

FIELD OF THE INVENTION The present invention relates to composite friction elements for brakes and clutches, and more particularly to improved friction elements, composites and methods of manufacturing the same.

1 is a perspective view schematically showing an apparatus and a preferred method of carrying out the invention.

2 is a view similar to FIG. 1 showing a method of manufacturing a clutch lining according to the invention.

3 is a perspective view of a conventional woven panel of a reinforcing fiber according to the present invention.

FIG. 4 is a view similar to FIG. 3 showing the woven panel of FIG. 3 following a needling process for carrying out the steps of the preferred method of the present invention.

5 is a front view illustrating the needling of multiple panels of a reinforcement panel.

FIG. 6 is a front view showing a needle for use in the operation of FIG. 5; FIG.

7 is a view similar to FIG. 3 showing an alternative embodiment of a woven panel for carrying out the preferred method of the invention.

8 is a plan view of a conventional stitching panel of reinforcing fibers according to the present invention.

9 is a plan view of a conventional braiding panel of reinforcing fiber according to the present invention.

FIG. 10 is a perspective view schematically showing a preferred method and apparatus including secondary material to provide an integral backing or reinforcement for carrying out the present invention. FIG.

11 is a perspective view of one product made according to the present invention.

12 is a perspective view of another product made according to the invention.

It is a primary object of the present invention to provide an improved composite, structure and friction lining manufacturing method for all types of brakes and clutches.

Another object of the present invention is to provide an improved drawing process for the manufacture of friction linings for brakes and clutches.

Another object of the present invention is to provide a means for simultaneously producing a friction unit having a backing structure by a single process.

According to a main aspect of the present invention, the friction unit comprises a composite of controlled density and orientation of an array of primary reinforcing fibers in a phenolic resin produced by a drawing process and having a selected amount of one or more organic and inorganic friction modifiers.

Another aspect of the invention provides a method of selecting a uniform array of primary strands of reinforcing fibers impregnated with a phenolic resin material into which a particular friction modifier and process agent are mixed, and a body having at least a portion of the three-dimensional shape of the friction unit. And a friction unit manufactured by a continuous process comprising pulling an impregnating strand of reinforcing fiber through the compound forming die to form a die, and selectively cutting the body into a plurality of friction units.

Another aspect of the present invention provides a method for fabricating a continuous process comprising pulling an impregnating strand of reinforcing fiber through a composite forming die with a panel of secondary material in a simultaneous process to provide an integral backing or reinforcement to the friction unit. A friction unit.

These and other objects and advantages of the present invention will become apparent from the following description when read in conjunction with the accompanying drawings.

The present invention is directed to an improvement in a process known as drawing for the production of articles from composite materials. The drawing process is a process in which a product or article is formed in a die by pulling material through a die where they are molded as at least one critical dimension or shape in the process. This is distinct from the extrusion process in which the material is pressed or pressed through the die under pressure and the alternative process in which the product is molded separately in the pressure cavity die.

Referring to FIG. 1, there is schematically shown an exemplary system for carrying out an exemplary series of steps for manufacturing a lining for a brake and clutch according to the present invention. The system, generally indicated at 10, includes a source of reinforcing fibers or fibers, such as one or more spools or rolls 12 from which an array of fibers or a panel 14 of a plurality of strands of elongate continuous fibers is pulled therefrom. . The array or panel of fibers is impregnated with a suitable resin, such as by passing through a wet bath 16 of a suitable resin, such as a phenolic resin, or a suitable injection chamber, through a molding die from which the composite panel 20 emerges.

The panel of reinforcing fiber is pulled through the die 18 by suitable pulling or pulling means 22, such as a roller pulling device as shown. The traction device shown includes a pair of rollers 24, 26 through which the panel 20 passes and grips it and is pulled through the die. The roller may be driven by a suitable motor 28 which may be powered by any suitable means such as electric, air, hydraulic and other suitable power means. Other types of traction devices, such as hydraulically powered reciprocating traction grippers or retractors (not shown) may also be used. After the panel emerges from the die, the portion of the desired shape is cut therefrom by any suitable cutting means 30 such as a water jet, abrasive cutter, laser plasma, stamping or other means.

As shown in FIG. 1, the expression panel 20 is cut into a suitable brake pad such as an arcuate shape. This cutting may be accomplished by any suitable cutting means such as a water jet, abrasive cutter, laser plasma, stamping or other means. The cutting process may depend to some extent on the thickness and content of the material. Relatively thin materials, such as in small brake pads and clutch pads, may be cut by stamping with a die cutter or other suitable means. Certain clutch plates and abrasive discs for various applications may be as thin as a single layer of woven reinforcing fibers. Thicker materials, such as in heavy duty brake pads and shoes, may require other cutting means such as water jets and the like.

As shown in FIG. 2, the expression panel 20 is cut into clutch pads or disks of ring or annular shape. This cutting may be accomplished by a die cutter 36 powered by an air or hydraulic cylinder 38. Since the materials are relatively thin as in clutch plates, they can be easily cut by stamping with a die cutter. Clutch plates for some applications, such as automatic transmissions, may be as thin as a single layer of woven reinforcing fibers and may include integral backings or reinforcements.

The combination of fiber and resin is molded to at least the specific dimensions and shapes of the portion of the article of the die and cured by heat before emergence from the die. In the embodiment shown, a generally flat rectangular panel 20 is formed from which the brake or clutch pad 32 is cut or stamped. This is a continuous process that forms dimensions and at least certain portions, such as friction surfaces and thicknesses of articles of manufacture. The fibers may be in the form of individual strands, woven fabrics, matting, or stitching fabrics or combinations thereof. However, a preferred form of reinforcing fiber is in a woven panel or mating where the primary fiber is in the machine direction and the cross woven fiber is perpendicular to the primary fiber or strand. Crossover fibers may in some cases be alternately other than 90 ° relative to the primary fiber.

Referring to FIG. 3, an exemplary preferred reinforcement panel is shown and generally indicated by 40. The panel is shown as a typical weave of fiber 42, which may be a primary fiber extending in the machine or traction direction. Crossover fiber 44, which may be considered a secondary fiber, extends substantially 90 ° across fiber 42 of a typical weave. The illustrated fibers 42 and 44 may be single strands or fibers or may be strings of multiple fibers of the same or different types. The primary reinforcing fibers 42, 44 for the brake pads or linings are preferably glass fibers, but the pads may comprise other materials and fibers or combinations thereof. In addition, other fibers may be woven or distributed in glass fiber in various selected distributions and proportions to alter or enhance certain properties. For example, various fibers may be distributed at various concentrations substantially uniformly throughout the unit to optimize various parameters such as internal laminar shear strength, wear, fade and cooling. The addition of secondary reinforcement fibers can be accomplished in a number of different ways.

Many different fibers or strands and combinations may be used including, but not limited to, glass, rock, ceramic, carbon, graphite, aramid, nomex, kevlar, wool, and cotton fibers of other organic and inorganic materials. Various metal fibers, such as copper and aluminum, may also be used in various ratios with the nonmetallic fibers. In one preferred composite, the fiber is about 20% by weight of wool and / or cotton fiber. Fiber optics may also be included to provide performance monitoring and validation testing of the final portion for evaluation or end use.

As shown, manufacturing systems and processes provide controlled predetermined orientation of the primary fiber, as well as controlled predetermined uniformity and density of the primary fiber in the resin matrix. For example, composites of friction devices determine many of their properties, such as durability, heat resistance, and friction resistance. In this process, the primary fiber may be uniformly oriented and controllably distributed at any suitable angle to the friction surface of the brake pad or friction device. Thus, processes and materials have the ability to provide good, predictable and consistent performance.

The process may include the addition of secondary fibers extending laterally to the primary fiber to add shear strength and other mechanical properties to the unit. In one form of the process,

The panel 16 of fiber or strand is coated or wetted with the resin in any suitable manner prior to (prepreg) or during the drawing process. In the illustrated embodiment, the fiber is shown passed through or into a bath or injector chamber 16 of a suitable liquid resin contained within a reservoir 20 for wetting or impregnating the fiber or strand. The fibers may also be impregnated with resin (pre-preg) prior to the process, or they may be subjected to resin injection during the drawing process by drawing it through a bath or by pumping the resin into it from a header surrounding the panel or roving of the fiber. May be wetted by The fibers may preferably be actual numbers of hundreds or thousands in the mating of fibers in which a plurality of rows are parallel and stitched together or other layers of different orientations may be inserted. In the preferred system shown, the fiber is in the form of a woven panel or mat that is guided into the die 18 and cut or formed to the width of the die to impart at least part of the shape or final shape of the friction unit.

Strands, in particular glass fibers, may require the application of compounds or chemicals to ensure dimensional processing, i.e. good or complete wetting of the fibers and good bonding between the fibers and the matrix and between the layers of the fibers. Bulking rovings (bundles of fibers or strands) are preferably used. Bulking roving is formed by a process in which strand roving is broken or disrupted by forced cooling air. This process provides two useful properties: 1) increased diameter to assist in providing fillers to lower the glass content draw, and 2) “cracking” provides good mechanical bonding in all axes within the resin matrix. will be.

The resin-impregnated or wet panels of the fibers pass through or are pulled through the die 18, where they are formed into at least a portion of a predetermined shape and at least partially cured if not complete. The fiber and resin composite is preferably at least partially cured in the die by any suitable or other means, such as exothermic or thermally radiative, and the fibers are disposed in the body of the unit and maintained under tension. The composite unit is pulled under tension from the die in the form of an elongate continuous bar or panel 20 having at least a portion of the surrounding shape of the brake or clutch pad or other article to be produced. In the case of brake and clutch pads, the bar or panel preferably has the friction and mounting surface shape of the final pad. The bar or panel 20 is pulled from the die 18 by any suitable means, such as a hydraulic retractor, a traction device (not shown), etc., and is cut and positioned into individual friction or brake pad units or parts in the illustrated embodiment. This drawing process provides a composite that is substantially controlled with a predetermined distribution and orientation of primary fibers throughout the body of the friction unit. This helps to maintain a high degree of uniformity between the units as well as the various parameters of the units and their final performance.

In some cases it may be desirable to provide different angles of the fiber relative to the friction surface. For example, it may be desirable to have fibers that are perpendicular to a friction surface on the order of 45 °. This can be accomplished by cutting the friction unit from the bar at an angle with respect to its axis.

The brake pads may be placed on the conveyor belt or otherwise moved in place for further processing, such as attachment to the backing plate, when cut from the panel. The pad or lining may be attached to the backing plate or shoe by adhesive bonding or the like. The pads are then accumulated in a suitable manner in a suitable storage container or bin, where they are then packaged and shipped.

The density and mixture of primary fibers as well as secondary fibers may be varied to suit particular applications. Specifically, however, in the case of brake shoes, the orientation of the primary fiber may be located on the drum in a transverse direction relative to the drum surface. The fiber is pulled through a die having a curve or arc of a predetermined shoe and selectively cut in the width direction. In this application, the cut surface does not exhibit a friction surface. Secondary preparation steps such as grinding should be performed to obtain the desired surface. This also applies to various pad and clutch applicators as described herein.

Although the brake pads have been described in the process, not only the clutch friction unit and brake shoe lining, but also abrasive friction disks may also be produced by this process. The die may be set to form one circumferential surface or contour of the expression article and include an annular shape. In addition, the die may be set to provide at least one dimension of the article to be manufactured. In the case of a pad for a disc brake, in one embodiment, the fibers are evenly oriented at an angle that is desired to be perpendicular to the friction surface for best manufacturing efficiency. However, in certain applications, an orientation parallel to the friction surface is satisfied or even desirable for manufacturing as well as performance.

The shoe lining is formed by a drawing process in the form of a thin arcuate slab, which may be cut to the width as described above for the pad. This provides an economical technique for forming a consistently uniform unit. However, if the orientation of the fiber perpendicular to the frictional surface is desired, rectangular slabs may be cut along the arc to form a curved frictional surface.

The article may be cut from the draw bar by any suitable means such as laser, water or other means. The methods and processes of the present invention provide a very efficient manufacturing process for the production of high quality friction units with asbestos free and / or controlled uniform composites and qualities. The drawing process allows for careful control of fiber density fillers and friction compositions, mixtures and orientations on a high speed and continuous basis.

The primary reinforcing fibers 14 for the brake pads or linings are preferably glass fibers, although the pads may comprise other materials and fibers or combinations thereof. In addition, other fibers may be woven or distributed into glass fibers in various selected distributions and ratios to alter or enhance certain properties. For example, various fibers may be distributed at various concentrations substantially uniformly throughout the unit to optimize various parameters such as internal laminar shear strength, wear, fade and cooling. The addition of secondary reinforcing fibers can be accomplished in a variety of ways. A number of different fibers or strands, including glass fibers, rock, ceramic, carbon, graphite, aramid, nomex, wool and cotton fibers of other organic and inorganic materials and Combinations may be used, but are not limited to such. Various metal fibers, such as copper and aluminum, may also be used in various ratios with the nonmetallic fibers.

The preferred process shown utilizes a plurality of layered fabric panels of reinforcing fibers. In some cases, additional shear strength may be required between layers of reinforcing fibers. One preferred method of obtaining sufficient strength is by the needling method as shown in FIGS. 4 and 5. This process involves passing a plurality of barbed needles through a panel of fibers as the panel passes through the bottom of the needle. As shown, the panel 40 has a portion or strand of fiber 46, referred to herein as a lower portion, that extends downward from the panel. Similar strands of fiber may also extend upwards if desired. In a preferred method, the multiple layers of the reinforcement panel are brought together so that each needle attachment is mixed simultaneously to connect or join the woven panels together. Fiber from each panel is pressed into adjacent panels resulting in high strength mechanical bonding between adjacent panels. This improves the bonding between the layers and the inner layer shear strength of the final product and limits the distortion caused by the pulling force of the draw.

An exemplary apparatus for performing this needling procedure is shown in FIG. 5 and generally indicated by 48. The apparatus comprises a support 50 which is preferably in the form of a generally rectangular panel on which an array of a plurality of barbed needles 52 is mounted. A reciprocating power unit 54, such as a hydraulic or pneumatic cylinder, is connected to the support 50 and moves it up and down to move the panel 56 or one or more layers of reinforcing fiber forming rises and falls as specifically required. Press the needle through. This array of rises and falls tends to constrain the panels together once they are in contact with each other during processing to improve the inner or inner laminar shear strength of the final product.

With reference to FIG. 6, an exemplary embodiment of the needle is shown and generally indicated by the numeral 62. Needle 62 includes an elongated shank 64 having a mounting end 68 and a sharp end 70. A pair of descending barbs 72 are formed at the bottom of the shank that is sharpened in the direction of the needle tip. A pair of rising barbs are formed on the shank on top of the falling barb and sharpened toward the mounting end of the needle.

A pair of panels may also be formed in any number of other ways as shown in FIGS. 7, 8, and 9. Referring first to FIG. 7, panel 80 is formed of woven fibers or strands that intersect in a traditional manner. However, pairs of strands 82 extending in one direction are woven into a single cross strand 84.

Shown in FIG. 8 is a mat 86 formed from a bundle (vertically oriented) of a plurality of fibers 88 held together by stitching 90 (extending horizontally). Their second panels are shown stacked at an angle of about 45 °. They are stacked at a number of different angles of 90 ° in several degrees.

9 shows a braided mat 92 formed by braiding multiple strings or bundles 94 of fibers. The braiding may be relatively loose or tightened as desired. Their layers and the mat or panel of FIG. 8 may also need to be needled for additional composite reinforcement. In addition to the reinforcement of the extension of the composite unit, any one or a combination of two or all of the mats or panels of the fiber may be used.

1. Referring to FIG. 10, another method for schematically performing an exemplary series of steps for manufacturing a product such as a friction lining for a brake and a clutch in accordance with the present invention is schematically illustrated. The method is performed in a substantially identical system, generally indicated at 10, as described above. The system includes a source of reinforcing fibers or fabric, such as one or more spools or rolls 12 from which panels 14 of a plurality of strands of elongate continuous fibers or arrays of fibers are towed. A panel or array of fibers is impregnated with a suitable resin, such as through a suitable infusion chamber or wet bath 16 of a suitable resin, such as a phenolic resin, and from there through a forming die 18 which the composite panel 20 expresses. do. A backing or reinforcement panel 96 of metal or other suitable substantially rigid material is passed through and bonded to the system having the resin impregnated fabric panel. Composite fabric panels and resins form a top layer bonded to a backing panel that emerges from a drawing device or system. The composite panel 98 may be cut into a suitably formed unit 100 having a friction surface 102 and a backing surface 104 in combination thereof. This forms a unit that may be used for the brake or clutch rotor. The backing material may be any suitable material, such as solid metal panels, perforated metal panels, metal screens, composites, and the like. This process can eliminate the additional step of conjugation.

One preferred composite unit is formed from an aluminum backing for producing a lightweight brake rotor with a durable friction surface. The rotor may be detachably attached to the hub of the vehicle to provide a reduction in the under spring weight of the vehicle wheel assembly. In an alternative manufacturing method, rigid panels may be interposed between the friction panels during the drawing process to form panels with opposite friction surfaces as shown in FIG. 11. As shown, the unit 106 has a compound surface 108 on one side of the rigid panel 110 and a compound surface 112 on the other side. These units can be used as clutches or brake discs or rotors.

Referring to FIG. 12, an embodiment is illustrated in which the stacked brake rotor includes a central lightweight disk 118 having a hub 120 for removable attachment to the axle hub of the vehicle. The pair of rotor disks 122 and 124 are formed of a composite material and can be attached to opposite sides of the central disk to provide a friction surface for engagement by appropriate brake pads. This configuration allows the use of lightweight materials such as aluminum for the central hub and main rotor 118 to reduce the unloaded weight of the automatic suspension. Aluminum proved to be unsuitable for conventional brake rotors because it lacked sufficient hardness. This configuration allows lightweight aluminum rotors to be used with suitable attachable wear surfaces.

The manufacturing systems and processes illustrated and described herein provide a controlled predetermined orientation of the primary fibers and a controlled predetermined uniformity and density of the primary fibers in the resin matrix. By way of example, the composition of the friction device determines its many properties such as durability, heat resistance and friction resistance. In this process, the primary fiber may be uniformly controllably distributed and oriented at any suitable angle to the friction surface of the brake pad or friction device.

Milled or chopped fibers such as glass, ceramic, kevlar, steel, wool or cotton fibers, etc. can also be introduced and added into the matrix material so that they can be picked up by the primary fiber strands as they pass through the resin. The chopped fibers can be from about 1% to about 5% by weight of the matrix material. Short fibers are more or less uniformly distributed throughout the matrix, suitably in the approximate range of about 0.015 inches to about 0.062 inches. Dispersion of this milled fiber provides crack and compression resistance of the area being machined for multiaxial mechanical reinforcement and mounting purposes. In this process, milled or chopped fibers may be mixed in the primary resin reservoir, or alternatively, two resin reservoirs may be used. In one arrangement, the first tank contains a low viscosity resin to improve the wetting of the fiber (preferably predominantly glass fiber) upon passage. The fiber then passes through a second tank of higher viscosity resin, which includes a plurality of fillers and chopped wool, cotton or other fibers. The chopped fibers are suitably comprised of about 1% to 5% of the reinforcing fibers. These are appropriate modifications of the handling equipment and are picked up by the primary fiber strands and generally extend in the direction transverse to the primary fiber. Other fibers may also be used in this way.

These and transverse fibers can be used together or alternatively to achieve the desired shear strength. Alternatively, when necessary for the area to be machined for mounting purposes, the use of secondary panels or hardened composite metals or other types of materials, used as integral backings or reinforcements for the drawn composite, of woven or striped layers Changes can be utilized to provide the desired change in mechanical properties.

The matrix material may be any suitable resin, either thermoplastic or non-thermoplastic material, which may require various curing forms. It may be cured, for example, by cooling, heating or the use of UV or other radiation. However, the material must be able to enable the formation of the unit by the drawing process.

One suitable phenolic resin is available from BP Chemicals under product number J2041L and under the trade name "CELLBOND". This product is described as a highly viscous phenol for use in thermoset drawing, does not require any catalyst and provides a moderately fast line speed and curing cycle. Another suitable phenolic resin is Borden 429C, which is recently available from Boden Company, whose conversion has been improved. These resins are preferably present in the range of about 30% to about 60%, providing improved efficiency in manufacturing. In some cases, the manufactured units must be post-cured to ensure the best performance. For example, it may be baked at about 121-242 ° C. (250-500 ° F.) for one to several hours. Preheating may also be required for larger cross-section units. This may be considered in any suitable manner, such as by the use of an RF oven or a radiation thermal system, and generally requires a low temperature of about 26.7 to 65.6 ° C. (80 to 150 ° F.).

Another resin that is preferably added or combined with one of the above is the resorcinol modified phenolic resin developed by Inspec Chemical Corporation and available under the trade name Rescorciphen. The resin is preferably present in the range of about 0 to 20% by weight and preferably up to about 13.8% by weight. The resin may require the addition of a material such as BYK 9010 in an amount of up to about 2.5% by weight to control the viscosity of the mixture. The matrix material may be formulated to include heat dissipation and / or friction modifiers such as graphite and / or nonferrous metal powders and the like. For example, 1 to 10% by weight of one or more fillers and / or modifiers, such as graphite powder and / or one or more nonferrous metal powders, may be incorporated into the mixed material. Other materials such as, but not limited to, mineral fillers, rubber powder, copper powder, ceramic powder, nut shell powder (such as walnut or cashew). They may each be in an amount of 1 to 10% by weight and preferably in an amount of 3 to 5% by weight. Nut powder has been found to increase the shear strength of the unit and to improve the fade properties of the pads or linings. During braking, the heat destroys the nut shell powder, causing the nut shell oil to chemically bond with the resin polymer molecules in a process known as chain branching. This makes the polymer stronger and able to withstand the high temperatures that contribute to the brake fade. The ceramic powder is preferably in the form of hollow spheres of 7 to 10 microns. They have been found to function as mechanical lubricants during the drawing process and to improve the hardness and wear characteristics of the friction unit.

The preferred composition of the matrix material is about 0.0 to 2.5% wetting agent, about 0.0 to 10% barite (BaSO4), about 0.0 to 20% copper, about 0 to 5.0% walnut powder, about 0.0 to 5.0% talc Nital (CaMgSilicate1H2O), about 0.0 to 5.0% graphite, about 0.0 to 10% zinc oxide (friction enhancer), about 0.0 to 10% aluminum oxide (friction enhancer) and about 0.0 to 10% brass (friction enhancer) ) And about 0.0-2.5% of the mold release agent.

The following examples are intended to illustrate the invention and are not intended to be limiting. These examples are examples of compositions found to be satisfactory, but other compositions may be generated and used by those skilled in the art.

Example 1

Test samples of suitable products include about 0.035% wetting agent, about 5.5% barite (BaSO4), about 6.9% copper, about 2.8% walnut powder, about 2.8% talc nital (CaMgSilicate1H2O), about 3.5% It was formed with graphite, about 4.1% zinc oxide (friction enhancer), about 4.1% aluminum oxide (friction enhancer) and about 0.7% axle 1850 (mold release agent). The final product has about 46 weight percent glass, about 30.30 weight percent filler and about 33.37 weight percent resin. Glass is PPG E type phenol dimensioned woven fabric.

Example 2

Raw material weight%

Phenolic Resin 12.66

Barium Sulfate 15.19

Titanium Potassium 12.66

Kevlar 2.53

Calcium Fluoride 5.06

Antimony Trisulfide 2.53

Zircon 2.53

Aluminum oxide 1.27

Synthetic Graphite 7.59

Cork 9 2.53

Cashew Particles 7.59

Rubber 5.06

Calcium Oxide 1.27

Ceramic fiber 3.80

Vermiculite 10.13

Copper 7.59

Example 3

Raw material weight%

Phenolic Resin 10.53

Barium Sulfate 18.42

Steel wool 205 21.05

Kevlar 0.00

Calcium Fluoride 5.26

Zinc Sulfate 2.63

Zircon 3.95

Aluminum oxide 1.32

Synthetic Graphite 7.89

Cork 9 2.63

Cashew Particles 2.63

Rubber 5.26

Calcium Oxide 1.32

Ceramic fiber 3.95

Vermiculite 10.53

Example 4

Raw material weight%

Phenolic Resin 8.33

Barium Sulfate 16.67

Steel wool 205 38.86

Iron Sponge 15.63

Interfive 230 2.08

Zinc Sulfate 2.08

Blank 0.00

Zinc Oxide 0.00

Graphite A 505 6.25

Cork 9 2.08

Cashew Particles 2.08

Rubber 4.17

Blank 0.00

Blank 0.00

Vermiculite 4.17

The resin may comprise a compound or additive known as a molecular sieve to be reduced and not included by the article, which may be a water soluble group and may cause excessive voids in the article. Suitable such molecular sieve materials are available as sodium activity and carbazite hydroxides of many mesh sizes. These products absorb gases and water and reduce the potential voids or cracks caused by the gases and gases. Common channel names are sodium aluminosilicate and calcium aluminosilicate. They are in powder form and may be added in an amount of about 1 to 5% by weight of the resin. Another additive that appears to reduce the amount of water vapor formed during the process is barium oxide (BaSO ₄ ), commonly referred to as barite.

The resin may also be a non-aqueous group that may exclude or reduce the need for molecular sieves. The resin may also be a low condensation resin that generates less water by the product.

Fiber to vertical matrices may vary from about 1 part fiber to 2 part resin to about 3 part fiber to 1 part resin. Suitable fiber to matrix composites are from about 35% to 75% fiber to 25% to 40% resin or matrix mixture. The matrix preferably has 5 to 10% by weight of graphite powder, copper powder, aluminum powder and at least one of the aforementioned powders. In addition, aramid pulp and other synthetic fiber pulp may be added or distributed throughout the matrix material. Other materials, such as three composition sheets, may be added as needed.

Certain thermoplastic materials may be desirable for other specific applications. The thermoplastic material may be, for example, a suitable polyester and may include components such as powder of graphite or other materials to assist in friction control and heat dissipation. For example, about 1 to 10 weight percent graphite powder uniformly distributed throughout the thermoplastic material aids heat dissipation. Alternative composites may include small amounts of other materials, such as nonferrous metal powders such as copper, aluminum, and the like. For example, 1 to 10 weight percent copper powder may also be used to improve heat dissipation. Therefore, the composite must be compatible with the drawing process and at the same time provide a satisfactory friction unit.

It has been found that various ratios and composites of materials can affect the performance characteristics of the brake pads and lining units as well as the drawing process. For example, multiple test samples with multiple ranges of examples of composites have been configured and tested to optimize the friction unit. In recent tests, one of the most suitable compositions is about 0.035% wetting agent, about 5.5% BaSO 4, about 6.9% copper, about 2.8% walnut powder, about 2.8% talc nital (CaMgSilicate1H2O), about 3.5% Graphite, about 4.1% zinc oxide (friction enhancer), about 4.1% aluminum oxide (friction enhancer) and about 0.7% mold release agent. The final product has about 46 weight percent glass, about 30.30 weight percent filler and about 33.37 weight percent resin. Glass is a ppg e type phenol that is compatible with woven fabrics.

While the invention has been shown and described by way of specific embodiments, it should be understood that various changes and modifications may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

Claims (20)

In the compound friction unit, A three-dimensional composite body formed of a substantially uniform array of primary glass strands of primary reinforcement fibers, said reinforcement fibers being formed in at least one fabric array of at least one layer of fibers, said fibers being cross stitched, Bound together by a structure taken from the group consisting of weaving and braiding, the array of fibers is in a matrix of phenolic resin material, and the reinforcing fibers are distributed throughout the body in a predetermined uniform distribution and thereby A composite friction unit that forms a friction unit having a determined size and shape and a uniform distribution and alignment of fibers throughout. The mat array of claim 1, wherein the mat array comprises at least two layers of fibers comprising a first layer in a first orientation and a second layer in a second orientation that is about 45 ° to 90 ° relative to the first orientation. Friction unit. 3. The friction unit of claim 2, wherein the body is formed as a friction pad having a friction surface parallel to the primary fiber. 3. The friction unit of claim 2 wherein said fabric is formed as a woven panel and said body is formed with a friction surface parallel to the primary fiber. The friction unit of claim 1, wherein the fabric array of fibers is formed as a woven panel of at least two parallel braids of fibers. The method of claim 2, The primary reinforcing fiber constitutes about 35 to about 75 weight percent of the body, And the resin comprises 1 to 10% by weight of at least one powder taken from the group consisting of rubber, copper, aluminum, graphite, ceramic, talc, barite and nut shell powder. According to claim 1, The primary reinforcing fiber constitutes about 35 to about 75 weight percent of the body, The resin comprises 1-10% by weight of at least one powder taken from the group consisting of rubber, copper, aluminum, graphite, ceramic, talc, barite and nut shell powder, And the resin comprises about 5 to 10 wt% graphite powder, about 5 to 10 wt% copper powder and 3 to 5 wt% nut shell powder. 8. The friction unit of claim 7, wherein said mat array of fibers is a woven fabric of fibers. 8. The friction unit of claim 7, wherein said body is formed from a friction surface transverse to said primary fiber. 8. The friction unit of claim 7, wherein said body is formed from a friction surface parallel to the primary fiber. According to claim 1, The primary reinforcing fiber constitutes about 35 to about 75 weight percent of the body, The resin comprises 1-10% by weight of at least one powder taken from the group consisting of rubber, copper, aluminum, graphite, ceramic, talc, barite and nut shell powder, And the resin comprises about 5 to 10 wt% graphite powder, about 5 to 10 wt% copper powder and 3 to 5 wt% nut shell powder. The method of claim 1, wherein the resin is about 0.035% wetting agent, about 5.5% barite (BaSO 4), about 6.9% copper, about 2.8% walnut powder, about 2.8% talc nital (CaMgSilicateH 2 O), 3.5 A friction unit comprising% graphite, about 4.1% zinc oxide (friction enhancer), about 4.1% aluminum oxide (friction enhancer) and about 0.7% mold release agent. The friction unit of claim 12, wherein the friction unit comprises about 46.0 weight% glass, about 30.30 weight% filler, and about 33.7 weight% resin. 13. The friction unit of claim 12, wherein the primary reinforcing fiber is under tension in the body. In a continuous manufacturing process for producing a composite friction unit, Selecting a panel of a substantially uniform array of predominantly glass strands of primary reinforcing fibers, bound together by a process taken from the group comprising weaving, braiding and stitching; Wetting the array of primary reinforcing fibers with a phenolic resin material; Towing the wet array of reinforcing fibers with a predetermined uniform distribution and orientation through a compound forming die to form a body having at least a portion of the surrounding shape of the friction unit; Solidifying the main body by curing the resin; And A plurality of friction units selectively cutting at least the body into a plurality of friction units along one path transverse to the strand, thereby having a predetermined size and shape and a uniform distribution and alignment of fibers throughout Process of shaping. The method of claim 15, wherein the resin is about 0.035% wetting agent, about 5.5% barite (BaSO 4), about 6.9% copper, about 2.8% walnut powder, about 2.8% talc nital (CaMgSilicateH 2 O), 3.5 A process comprising% graphite, about 4.1% zinc oxide (friction enhancer), about 4.1% aluminum oxide (friction enhancer) and about 0.7% mold release agent. The process of claim 16 wherein the friction unit comprises about 46.0 weight% glass, about 30.30 weight% filler, and about 33.7 weight% resin. The process of claim 15 wherein the friction unit comprises about 46.0 wt% glass, about 30.30 wt% filler, and about 33.7 wt% resin. 19. The process of claim 18, wherein the primary reinforcing fiber is under tension in the body. The process of claim 15 wherein the primary reinforcing fiber is under tension in the body.