Plastic and nonmetallic article shaping or treating: processes – Mechanical shaping or molding to form or reform shaped article – To produce composite – plural part or multilayered article
Patent
1995-11-27
1998-09-15
Choi, Kathleen
Plastic and nonmetallic article shaping or treating: processes
Mechanical shaping or molding to form or reform shaped article
To produce composite, plural part or multilayered article
264259, 2642974, 156184, 156242, 156250, 156305, F16D 6902, D04H 148
Patent
active
058075186
DESCRIPTION:
BRIEF SUMMARY
This application is a national stage application filed under 35.U.S.C.37/ of PT/FR95/00320 on Mar. 6, 1995.
FIELD OF THE INVENTION
The present invention relates to a friction material designed for fitting to a device using friction in a liquid medium, and the method of producing such a friction material and the device to which it is fitted.
More particularly, such a friction material takes the form of a flat ring or a truncated cone and the device to which it is fitted is a clutch or brake disc, notably for an automatic gear box or associated therewith, operating in oil, or a synchronisation ring or cone for a manually-operated gearbox also operating in oil, such a device being installed in a vehicle.
BACKGROUND OF THE INVENTION
The friction materials used up to now for the aforementioned applications are of three types: materials of the paper type, sintered materials and graphite-containing moulded materials.
The materials of the paper type consist essentially of cellulose fibres impregnated with resin.
Such materials are obtained by a wet method using a normal paper-making process, that is to say by dispersing cellulose fibres in an aqueous solution containing a resin, then spinning and drying.
Such a method necessarily involves using short fibres, with an average length below one millimeter.
Materials of this type have the drawback of degrading very rapidly as soon as their temperature reaches 150.degree. C., which is the case when the device that is equipped with the friction material must, within a small space, transmit or absorb high torques at speeds which, in practice, are growing ever higher.
This situation now arises by virtue of, on the one hand, the increasing power of thermal engines and, on the other hand, the reduction in the size of the devices for transmitting engine torque, which make it necessary to increase the gripping pressure of the friction devices.
Sintered materials do not exhibit the above described drawback but, unlike with materials of the paper type, the coefficients of friction obtained are low.
Moreover, these materials generate damaging vibrations and noises.
Materials of the graphite-containing moulded type have a relatively high cost and do not permit stable transmission of a torque.
SUMMARY OF THE INVENTION
The aim of the invention is to overcome the aforementioned drawbacks by proposing a friction material for a liquid medium which has in particular a high, stable coefficient of friction, a high resistance to heating at high working pressures, and good resistance to wear.
A friction material for a liquid medium, according to the invention, is characterized in that it consists of a mat of fibres impregnated with a thermosetting resin, and in that the fibres have a length of at least 12 mm.
According to other characteristics taken separately or in combination:
the average length of the fibres is at most 120 mm;
the fibres are chosen from amongst the group of fibres of glass, wool, cotton, ceramic, polyacrylonitrile, preoxidized polyacrylonitrile and aramid;
fillers in powder form are incorporated into the mat, comprising all or some of the following elements or compounds: copper, rockwool, carbon (coke and/or reduced-powder carbon fibres, graphite), zirconium silicate, iron sulphide, alumina, rubber and diatoms;
fillers in the form of pulps are incorporated into the mat, comprising all or some of the following compounds: pulps of glass, aramid, acrylic and phenolic fibres;
the resin of the thermosetting type includes a polar solvent, preferably aqueous;
the thermosetting resin has latex and/or fillers in powder form added to it which comprise all or some of the following elements or compounds: copper, rockwool, carbon (coke and/or reduced-powder carbon fibres, graphite), zirconium silicate, iron sulphide, alumina, rubber and diatoms.
The method of producing the friction material according to the invention is characterized by the following steps:
a) a mixture of fibres of the same nature or of different natures as defined above is produced in a mixer;
b) the mixtu
REFERENCES:
patent: 2733797 (1956-02-01), Almen et al.
patent: 3936552 (1976-02-01), Krupp et al.
patent: 3971669 (1976-07-01), Wrzesien et al.
patent: 4130537 (1978-12-01), Bohrer
patent: 4369263 (1983-01-01), Matsushima et al.
patent: 4374211 (1983-02-01), Gallagher et al.
patent: 4743643 (1988-05-01), Royer
patent: 4775705 (1988-10-01), Parker et al.
patent: 4785029 (1988-11-01), Honma et al.
patent: 4790052 (1988-12-01), Olry
patent: 4836507 (1989-06-01), Yang
patent: 4861809 (1989-08-01), Ogawa et al.
patent: 4895882 (1990-01-01), Asano et al.
patent: 5273819 (1993-12-01), Jex
patent: 5304225 (1994-04-01), Gardziella et al.
JP910071291/92-410457 Derwent abstract, 29 Oct. 1992 International Search Report, 28 Jun. 1995.
Boutaud Jean-Pierre
Guerin Richard
Jacq Gerard
Menard Denis
LandOfFree
Friction material designed for fitting to a device employing fri does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Friction material designed for fitting to a device employing fri, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Friction material designed for fitting to a device employing fri will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-84392