Method for producing a friction body

Abstract

A method for producing a friction body, in particular a wet friction disk in a motor vehicle, the friction body turning about a rotational axis during operation. The friction body has a friction area and a connection area and the connection area of the friction body is connected to a friction body carrier. A friction body, in particular a wet friction disc in a motor vehicle, is also provided.

Claims

1. A method for producing a friction body, the friction body being adapted to rotate about a rotational axis during operation, the friction body comprising a friction area and a connection area, and wherein the friction body is connected to a friction body carrier in the connection area, the method comprising: pulp molding three moist paper blanks including fibers selected from a group consisting of cotton fibers and aramid fibers, placing the three moist paper blanks one above the other in an axial direction only in the connection area and then pressing the three paper blanks to a first defined thickness in the friction area and to a second defined thickness in the connection area with heating and reacting of a binding agent contained in the paper blanks to form the friction body, discharging moisture from the paper blanks during pressing, the binding agent contained in the paper blanks is still in a reactive state before the pressing, and wherein each of the paper blanks has at least one connection area, only one of the paper blanks has an area that is at least part of the friction area after completion of the friction body, the friction area of the friction body has a larger thickness than a thickness of the connection area after the pressing and the completion of the friction body, and installing the friction body in a clutch as a wet-running friction disk in a motor vehicle.

2. The method according to claim 1, wherein the pressing step is a hot-pressing process.

3. The method according to claim 1, wherein during the pressing step, the friction body is also dried, and during the drying, the moisture is discharged as water vapor via a vacuum or negative pressure.

4. The method according to claim 1, wherein the friction body carrier is a hub or a disk carrier.

5. The method according to claim 1, wherein the paper blanks are placed one above the other.

6. The method according to claim 5, wherein a first one of the paper blanks that has the friction area of the friction body after the completion of the friction body and second and third ones of the paper blanks are placed one above the other, wherein the first paper blank is arranged axially between the second and the third paper blanks.

7. The method according to claim 1, wherein the paper blank that has the friction area after the completion of the friction body has a different composition with respect to a formulation thereof than the other paper blanks.

8. The method according to claim 1, wherein the friction body is connected to the friction body carrier by teeth and the friction body has a toothed geometry in the connection area.

9. The method according to claim 1, wherein connection area is provided on the friction body on at least one of an outside in a radial direction or on an inside in the radial direction with respect to the rotational axis.

10. The method according to claim 1, wherein the friction area is defined along a radially outer edge of the friction body and the connection area is defined along a radially inner edge of the friction body.

11. The method according to claim 8, wherein the toothed geometry in the connection area is formed during the pressing step.

12. The method according to claim 8, wherein the toothed geometry in the connection area is formed after the pressing step by stamping.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Additional advantages and advantageous constructions of the invention are the subject matter of the following figure and also its description.

(2) Shown in detail are:

(3) FIG. 1 is a schematic diagram of the production method according to the invention for the friction body.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(4) FIG. 1 shows schematically the production method according to the invention for the friction body.

(5) Below, the terms connection area and toothed area are understood to be the same; the reference symbols 40 and 100 are allocated to the two terms. Below, the terms friction area and friction function area are understood to be the same; the reference symbol 70 is allocated to the two terms.

(6) Severalpreferably at least twopaper blanks 10, 20, 30 are placed one above the other in the area of the teeth 40 of each paper blank and then pressed 60 with each other to the defined thickness with during and the reaction of the binding agent that is contained in the paper blanks 10, 20, 30 and is not fully reacted, that is, is still reactive in a suitable hot-pressing and drying tool. The binding agent in the paper blanks 10, 20, 30 provides for a rigid connection between the paper blanks 10, 20, 30 after it reacts completely due to the hot-pressing process. The paper blanks 10, 20, 30 are pulp molding blanks, that is, paper blanks that are produced by a pulp molding method. The paper blanks 10, 20, 30 are still moist before the pressing. During the pressing 60, the tool discharges the still contained moisture as water vapor with the help of a vacuum or negative pressure. During the pressing 60, pressing, curing, and drying take place in a single processing step. So that the binding agent is fully reacted, a sufficiently high temperature is provided during the pressing in the hot-pressing and drying tool.

(7) Here, the tool can already form the toothed geometry. The area of the teeth 40 can be selectively on the inside in the radial direction, as shown in FIG. 1, or on the outside in the radial directiondepending on the technical conditions or target specifications. For example, the teeth can be formed for a hub arranged on the inside in the radial direction or for a disk carrier on the outside in the radial direction. The area of the teeth 40 does not extend into the friction function area 70. The respective dimensioning of the toothed area 40, the teeth, and also the friction function area 70 is realized for someone skilled in the art from the technical conditions or target specifications.

(8) The production of the toothed geometry in the toothed area 100 can be implemented such that the blanks 10, 20, 30 already contain the toothed geometry or alternatively such that the pressed parts are subjected after the pressing 60 to a stamping process in a stamping step for the production of the toothed geometry. Alternatively, the toothed geometry can also be discharged directly during the pressing 60.

(9) A pulp molding blank is understood to be a blank that is produced by a pulp molding method known to someone skilled in the art. Such a method is also described in the German Patent Application DE 10 2010 021 722.0. Here, a dispersion made from water and solids is suctioned onto a sieve-like surface, wherein the solids are deposited on the sieve-like structure. The shape of the sieve-like surface is selected so that the resulting blank assumes the desired shapefor example, an annular shape. In this way, stamping residue like that produced according to classical paper-making methods can be avoided in order to obtain the desired shape for the blank. Such a dispersion contains, in addition to water, for example, cotton fiber, aramid fiber, silicon dioxide, phenol resin, and processing aids that are typical for the production of paper.

(10) This solution of the objective according to the invention can be realized by a paper-making machine with conventional papers not at all or only with considerable loss of materials and significant technical changes to the paper-making machine.

(11) For the solution according to the invention, it is necessary that the binding agent is in a still uncured state, that is, in a still reactive, not yet fully reacted state in the paper blanks 10, 20, 30. Only in this way is it guaranteed that two or more paper blanks can be connected to each other with sufficient strength. The paper blanks are preferably still in a moist state before the pressing.

(12) The paper blanks 10, 20, 30 can be made from different materials for achieving optimum toothed characteristics on one hand and an optimum friction performance on the other.

(13) The toothed area 100 can be thicker or thinner than the actual friction function area 70 by means of varying the hot-pressing tool. If the toothed area 100 is thicker than the friction function area 70, stresses can be reduced during operation. If the toothed area 100 is thinner than the friction function area 70, this can be advantageous, for example, with respect to the design of the friction body carrier.

(14) Pulp molding blanks 10, 20, 30 that already contain the binding agentadvantageously a phenol resinare placed one above the other. The paper blanks 10, 20, 30 can be arranged as shown in FIG. 1 and are then pressed flat 60. The paper blanks 10, 20, 30 can also be pressed into a different final geometric shape, for example, conical.

(15) The first paper blank 10 and the second paper blank 20 or the first paper blank 10 and the third paper blank 30 in FIG. 1 can have different compositions in terms of their formulation. Here, the second and third paper blanks 20 and 30 that have no friction function area 70 and are used only for reinforcing the toothed area 100 have the same composition, while the first paper blank 10 that has the friction function area 70 has a different composition.

(16) It can be processed, in particular, with two or three paper blanks 10, 20, 30, wherein a paper blank has a friction function area 70.

(17) The toothed geometry in the toothed area 40, 100 can already be formed during the pressing 60, without requiring additional reworking.

(18) Alternatively, the toothed geometry could be formed by a stamping process.

(19) Selectively, groove geometry 120 could be formed in the friction function area 70 during the pressing 60 or due to subsequent grinding.

(20) The surfaces 90, 110 can then be finished by grinding.

(21) Selectively, both friction function surfaces 90, 110 could have different groove geometries 120.

(22) Obviously, the paper blank could also be treatedfor example, by means of a suitably shaped sieve-like surface in the pulp molding methodsuch that it already contains more material in the toothed area. Then only one paper blank would be necessary.

(23) The invention can be used advantageously in wet-running dual clutches but also for lining disks for automatic transmissions and converter-type transmissions. It can also be used in the field of synchronization and for lining disks for differentials. Other possible uses are in the field of wet-running motorcycle clutches.

(24) The present invention describes the production of a lining disk without the use of a carrier sheet and the associated bonding process.

LIST OF REFERENCE NUMBERS

(25) 10 First paper blank 20 Second paper blank 30 Third paper blank 40 Toothed area of the paper blank 50 Axis 60 Pressing: hot pressing and simultaneous drying 70 Friction functional area 80 Pressed area 90 Friction functional surface 100 Toothed area of the friction body 110 Friction functional surface 120 Groove geometry 200 Friction body