KR20180031759A - Wet friction material - Google Patents
Wet friction material Download PDFInfo
- Publication number
- KR20180031759A KR20180031759A KR1020187005351A KR20187005351A KR20180031759A KR 20180031759 A KR20180031759 A KR 20180031759A KR 1020187005351 A KR1020187005351 A KR 1020187005351A KR 20187005351 A KR20187005351 A KR 20187005351A KR 20180031759 A KR20180031759 A KR 20180031759A
- Authority
- KR
- South Korea
- Prior art keywords
- carbon fiber
- reinforced composite
- composite material
- wet friction
- carbonized
- Prior art date
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
- C04B35/62605—Treating the starting powders individually or as mixtures
- C04B35/62645—Thermal treatment of powders or mixtures thereof other than sintering
- C04B35/6267—Pyrolysis, carbonisation or auto-combustion reactions
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/71—Ceramic products containing macroscopic reinforcing agents
- C04B35/78—Ceramic products containing macroscopic reinforcing agents containing non-metallic materials
- C04B35/80—Fibres, filaments, whiskers, platelets, or the like
- C04B35/83—Carbon fibres in a carbon matrix
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D69/00—Friction linings; Attachment thereof; Selection of coacting friction substances or surfaces
- F16D69/02—Compositions of linings; Methods of manufacturing
- F16D69/023—Composite materials containing carbon and carbon fibres or fibres made of carbonizable material
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D69/00—Friction linings; Attachment thereof; Selection of coacting friction substances or surfaces
- F16D69/02—Compositions of linings; Methods of manufacturing
- F16D69/025—Compositions based on an organic binder
- F16D69/026—Compositions based on an organic binder containing fibres
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/48—Organic compounds becoming part of a ceramic after heat treatment, e.g. carbonising phenol resins
Abstract
The present invention relates to a wet friction material comprising a sheet-like carbon fiber-reinforced composite material containing at least one textile fabric made of carbon fibers embedded in a plastic matrix, wherein at least a portion of the wet friction surface of the carbon fiber- And is carbonized from the surface to a prescribed depth. The present invention also relates to a method for producing the wet friction material.
Description
The present invention relates to a wet friction material made of a carbon fiber-reinforced composite material, and a method of manufacturing the wet friction material.
A wet friction coating, or wet friction material, is used in a wet friction element, which acts to remove heat generated by friction contact, e.g., oil, from the friction surface of the friction partner. A homogeneous wet friction element is known from US 5 662 993 A for friction materials made from resin-impregnated woven fabrics woven from carbon fibers.
In addition, the applicant's EP 1 505 310 B1 of the present application describes a homogeneous wet friction material with improved wet-material release characteristics through a special structuring of the surface.
Humid friction materials made from carbon fiber reinforced plastics (CFRP) are characterized by high stability and high thermal conductivity due to carbon fiber, in particular compared to materials made of glass fiber reinforced plastics (GFRP). However, the humid friction material is disadvantageous in that it has a high static friction which increases breakaway torque and deteriorates "green shiftability ".
Experiments performed by the applicants of the present invention show that a wet friction material based on a pyrolyzed friction coating made of carbon fiber-reinforced carbon (CFRC) as described in US 5 895 716 A can be used in conjunction with static friction and other friction characteristics CFRP friction materials. However, this is also disadvantageous in relation to abrasion resistance during the useful life of the wet friction element, because the CFRC material is inherently very stable and has high rigidity, but because of its stiffness the material is very fragile and fragile.
It is therefore an object of the present invention to provide a wet friction material which is advantageous in relation to friction characteristics and abrasion resistance compared to known friction materials.
This objective is achieved by carbonizing the CFRP friction coating intentionally and only on the friction coating surface provided for friction. Thus, the CFRP material is only carbonized up to a certain depth of the friction coating, and is not continuously carbonized through the entire CFRP material.
Accordingly, one aspect of the invention is a wet friction material comprising a sheet-like carbon fiber-reinforced composite material containing at least one textile fabric made of carbon fibers embedded in a plastic matrix, the carbon fiber reinforced composite Characterized in that the surface of the material is carbonized at least locally to a defined depth from the surface.
The continued presence of the original CFRP material under the carbonized surface of the wetting friction material, i.e. in the direction away from the surface provided for friction, ensures that the wetting friction material does not lose its abrasion resistance virtually during normal operation, Friction characteristics can be used. This could not be predicted in this form, because it should have been assumed that it would have a detrimental effect on abrasion resistance.
All known sheet textile structures can be considered as textile fabrics made from carbon fibers. In addition to the woven fabrics described in the open references cited at the outset, knitted fabrics, braids, crocheted, non-woven fabrics and paper made from carbon fibers can be used.
According to one embodiment of the invention, the surface has a depth in the range of 5 [mu] m to 1000 [mu] m, preferably a depth in the range of 20 [mu] m to 500 [mu] m, more preferably a depth in the range of 40 [mu] Carbonized to a depth in the range of 占 퐉 to 200 占 퐉, and this depth is smaller than the total thickness of the sheet-like carbon fiber-reinforced composite material. Depending on the application, a thin carbonized surface may be sufficient to expose only the top carbon fibers of the plastic matrix, corresponding to a depth of approximately 5 to 15 [mu] m. The deeper the carbonization, or the thicker the carbonized layer on the surface of the wet friction element, the better the friction characteristics. From the depth of approximately 100 [mu] m, no appreciable improvement of the friction properties is seen. At the same time, the layer of CFRP material must be sufficiently thick to ensure abrasion resistance. Therefore, particularly preferably, the surface is carbonized to a depth of 100 [mu] m to 200 [mu] m.
The total thickness of the sheet-like carbon fiber-reinforced composite material may be different depending on the use of the wet friction material, and therefore is not particularly limited. Preferably, the sheet-like carbon fiber-reinforced composite material has a thickness in the range of 0.2 to 5 mm, more preferably 0.25 to 2 mm, even more preferably 0.3 to 1 mm.
Preferably, the plastic matrix is not carbonized at least 0.1 mm in thickness of the sheet-like carbon fiber-reinforced composite material. This ensures sufficient stability of the material. More preferably, the non-carbonized layer, i.e. the layer still in CFRP state in the sheet-like carbon fiber-reinforced composite, is at least 0.2 mm, even more preferably 0.3 mm.
According to a further embodiment of the invention, 10 to 100%, preferably 20 to 100%, more preferably 30 to 90% of the surface is carbonized. Thus, where stability and abrasion resistance are particularly important for each application of the wetting friction material, especially a highly stressed friction coating, a surface that is only partially carbonized is advantageous. For example, although not entirely, the carbonated regions may be placed side by side in a regular pattern, for example, in strip form. In this case, the wear of the CFRC surface is evenly distributed over the entire friction surface, i. E. Over the regions of the CFRP surface, which results in an overall improved friction characteristic.
According to a further embodiment of the present invention, the textile fabric comprises a woven fabric made of carbon fibers. The woven fabrics are particularly characterized in that their structure can lead to channel formation on the surface of the wet friction material, and thereby the wetting medium emissions can be controlled. This effect can be selectively set according to the type of weaving, for example twill weave.
According to a further embodiment of the present invention, the plastic matrix comprises at least one plastic material selected from the group consisting of a cured epoxy resin and a cured phenolic resin, preferably a phenolic resin. In this case, it is advantageous in particular that the phenolic resin has a high carbon residue after carbonization. It has been found that a denser carbon matrix improves the frictional properties and in particular increases the coefficient of friction.
Another aspect of the present invention is a method for producing a wet friction material according to the present invention. All of the features mentioned in connection with the first aspect of the present invention can be combined with the method described below properly, and vice versa. A method according to the invention relates to a method of making a wet friction material comprising the steps of:
a) providing a textile fabric made of carbon fibers,
b) impregnating the textile fabric with a plastic precursor,
c) at least partially curing the plastic precursor to obtain an at least partially cured carbon fiber reinforced composite material,
d) carbonizing said at least partially cured carbon fiber-reinforced composite material at a carbon fiber-reinforced composite material surface provided for wet friction, and
e) fully curing the plastic precursor if the carbon fiber-reinforced composite is only partially cured.
The manner of providing the textile fabric according to step a) is not particularly limited. For example, but not exclusively, textile fabrics can be fabricated directly from carbon fibers. It is also possible to produce fabrics from precursor fibers from carbon fibers, but not exclusively, polyacrylonitrile fibers or stabilized (oxidized) polyacrylonitrile fibers, for example.
Preferably, epoxy resin or phenolic resin is used as plastic precursor in step b). The benefits of this have already been discussed above.
In principle, the impregnation process can be carried out according to all known impregnation methods. Preferably, the textile fabric is fully impregnated to increase the homogeneity and stability of the subsequent composite as much as possible.
In step c) according to the invention, the textile fabric impregnated with the plastic precursor can only be cured completely or partly. In the latter case, a prepreg capable of molding more easily than that obtained when the plastic precursor is completely cured is obtained.
According to a further embodiment of the method according to the invention, the surface according to step d) is at least locally and to a depth of the order of 5 [mu] m to 1000 [mu] m, preferably to a depth of the order of 20 [ Is carbonized to a depth of about 40 μm to 350 μm, particularly preferably to a depth of about 100 μm to 200 μm. The corresponding description of the first aspect of the present invention is applied here.
Preferably, 10 to 100%, preferably 30 to 100%, more preferably 40 to 90% of the surface is carbonized in step d). Here, the corresponding description of the first aspect of the present invention is applied.
According to a further embodiment of the method according to the invention, the carbonization is carried out by laser irradiation. By using laser irradiation, it is possible that even very thin layers can be carbonized to precisely defined depths because the energy input is very precise, and this carbonization causes additional undesirable carbonization due to heat dissipation in the object to be carbonized So that it can be prevented. This is surprisingly effective also in carbon fiber reinforced composite materials. Because the thermal conductivity of the carbon fibers is so high that it is assumed that carbonization proceeds over the entire thickness of the wet friction material. However, it is not. In this case, the type of the laser is not particularly limited. For example, a CO 2 laser may be used.
The temperature required for carbonization is typically 600 ° C to 1000 ° C. However, in the case of carbonization by laser irradiation according to the following example, the carbonization depth suddenly increases from a temperature of approximately 800 캜. Therefore, from about this temperature, the carbonization depth can not be controlled so effectively. In this case, the temperature required for carbonization is preferably 600 ° C to 780 ° C. A further advantage of this temperature range is that only the matrix is carbonized and the carbon fibers do not change structurally.
Carbonization can also be performed using any other suitable process. However, according to the present invention, carbonization or partial carbonization of a sheet-like carbon fiber-reinforced composite material in a common carbonization furnace is not carried out, since in this case the composite material is uniformly partially or completely Carbonization. The advantages of the present invention can not be achieved unless measures are taken to prevent the surface of the sheet-like carbon fiber-reinforced composite material from being carbonized in the furnace. However, in this case, a general carbon furnace is not used.
In the context of the present invention, the term "carbonization" is synonymous with the term "pyrolysis ". Both are known to those skilled in the art to run at high temperatures. In addition, the carbonization is preferably carried out in an inert gas atmosphere. This is advantageous in that most of the carbon produced during carbonization is not oxidized and therefore is not corroded.
According to a further embodiment of the method according to the invention, at least the textile fabric impregnated after step b), or the partially cured carbon fiber-reinforced composite material, is compacted under pressure. This consolidation is typically accomplished by mechanical presses. This pressing step can be performed not only before but also during the at least partial curing of the plastic precursor. Alternatively or additionally, it is possible that the already carbonized prepreg on the surface undergoes a pressing step before and / or during the plastic precursor is fully cured. In principle, the pressing step can be carried out at any time after impregnation until the carbon fiber-reinforced composite material is completely cured. However, the pressing step is not usually carried out during the carbonization in view of practical use. The compaction according to this embodiment increases the stability of the wet friction material.
According to a further embodiment of the method according to the invention, an at least partially cured carbon fiber-reinforced composite material is applied to the substrate. The substrate may be formed differently depending on the use. It essentially acts as a support material for the friction coating in which the wet friction material according to the invention will be present in the final product. For example, although not exclusively, the wet friction material according to the present invention may be used in clutches, such as multi-plate clutches and cone clutches, for example in synchronizer rings. In this case, the corresponding substrate is usually made of metal. Application to the substrate can be performed at any time after at least partial curing (step c). However, preferably the application to the substrate is carried out after the surface is carbonized. This prevents damage to the joints between the friction material and the substrate caused by the temperature rise that occurs during carbonization. Due to the high thermal conductivity of the carbon fibers, the heat generated during carbonization of the surface is conducted to the junction between the friction material and the substrate through the entire thickness of the wet friction coating. The type of application or bonding is not particularly limited. Typically, the wet friction material is applied to the substrate by an adhesive.
According to one preferred embodiment of the method according to the invention, the compaction is carried out before the carbonization, and the wet friction material is applied to the substrate following the carbonization. This sequence has many advantages in material handling during process run. In addition, if the pressing step is performed only after carbonization, the carbonized layer may be damaged during careless handling.
Example:
To produce a wet friction material according to the present invention, as a first step, a woven fabric made of carbon fibers having a weight per unit area of 270 g / m < 2 > and a thickness of 900 mu m was prepared. The woven fabric was impregnated with a phenolic resin system and then cured at 150 占 폚.
The surface was irradiated with a CO 2 laser having an output of 100 mW, whereby the surface was carbonized to a depth of 250 탆. The carbonization depth was checked using a simple scratch test because a somewhat fragile carbonized layer could easily be removed from the underlying CFRP material.
The longer a point on the surface is exposed to laser radiation, the hotter the surface becomes. At the same time, the generation temperature can be measured using infrared technology. The temperature dependence of the carbonization depth in this example is shown in the following table.
(Corresponding to carbonization depth)
Claims (14)
Wherein at least a portion of the surface of the carbon fiber-reinforced composite material provided for wetting is carbonized to a prescribed depth from the surface.
a) providing a textile fabric made of carbon fibers,
b) impregnating the textile fabric with a plastic precursor,
c) at least partially curing the plastic precursor to obtain an at least partially cured carbon fiber reinforced composite material,
d) carbonizing the at least partially cured carbon fiber-reinforced composite material at the wet friction surface of the carbon fiber-reinforced composite material, and
e) if the carbon fiber-reinforced composite material is only partially cured, the step of fully curing the plastic precursor
Of the wet friction material.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102015214496.8 | 2015-07-30 | ||
| DE102015214496.8A DE102015214496A1 (en) | 2015-07-30 | 2015-07-30 | Nassreibmaterial |
| PCT/EP2016/067870 WO2017017125A1 (en) | 2015-07-30 | 2016-07-27 | Wet-friction material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| KR20180031759A true KR20180031759A (en) | 2018-03-28 |
Family
ID=56801499
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR1020187005351A KR20180031759A (en) | 2015-07-30 | 2016-07-27 | Wet friction material |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP3328814A1 (en) |
| KR (1) | KR20180031759A (en) |
| CN (1) | CN107848897A (en) |
| DE (1) | DE102015214496A1 (en) |
| WO (1) | WO2017017125A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102017214778A1 (en) * | 2017-08-23 | 2019-02-28 | Sgl Carbon Se | Alternative joining method |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3516759A1 (en) * | 1984-06-08 | 1985-12-12 | Allied Corp., Morristown, N.J. | Process for the heat treatment of a brake-shoe friction surface |
| US5895716A (en) | 1995-07-18 | 1999-04-20 | The B.F. Goodrich Company | Wet friction materials, methods of making them, and apparatus containing the same |
| US5662993A (en) | 1995-09-08 | 1997-09-02 | General Motors Corporation | Carbon-based friction material for automotive continuous slip service |
| US5952249A (en) * | 1996-12-17 | 1999-09-14 | Textron Systems Corporation | Amorphous carbon-coated carbon fabric wet friction material |
| DE19928858C2 (en) * | 1999-06-24 | 2003-08-07 | Ruetgers Automotive Ag | Method and device for producing a brake pad |
| DE50113121D1 (en) * | 2001-06-01 | 2007-11-22 | Tmd Friction Gmbh | Method for improving a brake shoe for disc brakes and such a brake shoe |
| ES2291243T3 (en) * | 2001-06-01 | 2008-03-01 | Tmd Friction Gmbh | PROCEDURE FOR MANUFACTURING A CLAMP FOR DISC BRAKES. |
| DE10200240B4 (en) * | 2002-01-05 | 2005-03-17 | Tmd Friction Gmbh | Method and apparatus for heat treating a friction lining |
| JP2003130106A (en) * | 2001-10-26 | 2003-05-08 | Aisin Chem Co Ltd | Wet friction material and manufacturing method therefor |
| DE10334881A1 (en) * | 2003-07-29 | 2005-03-03 | Sgl Carbon Ag | A method of making a carbon fiber fabric-based friction material for wet friction members and friction material produced by the method |
| JP2008111546A (en) * | 2006-10-03 | 2008-05-15 | Aisin Chem Co Ltd | Wet friction material and method of producing the same |
| CN101805200B (en) * | 2010-03-17 | 2012-05-23 | 上海大学 | Method for producing carbon/carbone composite material for bearings |
| EP2471764B1 (en) * | 2010-12-28 | 2016-05-11 | SGL Carbon SE | Process for producing friction disks having a structured ceramic friction Layer |
| US9550701B2 (en) * | 2013-07-25 | 2017-01-24 | Honeywell International Inc. | Carbon-carbon composites including isotropic carbon encapsulating layer and methods of forming the same |
-
2015
- 2015-07-30 DE DE102015214496.8A patent/DE102015214496A1/en not_active Withdrawn
-
2016
- 2016-07-27 KR KR1020187005351A patent/KR20180031759A/en not_active Application Discontinuation
- 2016-07-27 WO PCT/EP2016/067870 patent/WO2017017125A1/en active Application Filing
- 2016-07-27 EP EP16757160.3A patent/EP3328814A1/en not_active Withdrawn
- 2016-07-27 CN CN201680044689.5A patent/CN107848897A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| CN107848897A (en) | 2018-03-27 |
| EP3328814A1 (en) | 2018-06-06 |
| WO2017017125A1 (en) | 2017-02-02 |
| DE102015214496A1 (en) | 2017-02-02 |
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| A201 | Request for examination | ||
| E902 | Notification of reason for refusal | ||
| E902 | Notification of reason for refusal | ||
| E601 | Decision to refuse application |