METHOD FOR THE PRODUCTION OF A WET FRICTION LINING, AND WET FRICTION LINING

Abstract

The invention relates to a method for producing a wet friction lining wherein an oil is delivered through pores to a device operated using oil. In a method in which oil delivery from the wet lining is adjustable regardless of the production process for the wet friction lining, the pores are formed using a perforation process.

Claims

1. A method for the production of a wet friction lining, in which oil is delivered through pores to a device operated using oil, the method comprising forming the pores in the wet friction lining by a perforation process.

2. The method according to claim 1, wherein the pores are formed by laser perforation.

3. The method according to claim 1, wherein the pores are formed by mechanical perforation.

4. The method according to claim 1, wherein the pores are formed by electrostatic micro-perforation.

5. The method according to claim 1, further comprising treating a top layer of the wet friction lining by the perforation process and subsequently applying the top layer on a bottom layer.

6. The method according to claim 1, further comprising applying a top layer of the wet friction lining on a bottom layer and subsequently forming the pores of the top layer by the perforation process.

7. A wet friction lining for a device operated using oil, which comprises pores for oil delivery to the device, the pores are generated as perforations in a single layer friction lining and have at least one of a pore size or pore density based on the perforations.

8. The wet friction lining according to claim 7, wherein the friction lining comprising the pores generated as perforations forms a top layer which is arranged on a bottom layer having a higher porosity than the top layer.

9. The wet friction lining according to claim 8, wherein the top layer comprising the pores generated as perforations is connected to the bottom layer by lamination or a separate adhesive layer.

10. The wet friction lining according to claim 8, wherein the pores formed as perforations penetrate the top layer partially or completely.

11. The method according to claim 4, wherein the electrostatic microperformation is performed using an electrostatic discharge.

12. The method according to claim 5, wherein the top layer is laminated to the bottom layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The invention allows numerous embodiments. One of them shall be explained in greater detail based on the FIGURE shown in the drawing.

[0019] Shown is:

[0020] FIG. 1 an exemplary embodiment of a wet friction lining according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] FIG. 1 shows an exemplary embodiment of a wet friction lining 1 according to the invention as used for a clutch of a motor vehicle. The wet friction lining 1 comprises two layers. A bottom layer 2 exhibits high porosity in order to absorb oil. Based on the high porosity this bottom layer 2 has a high oil penetration and oil delivery speed. The top layer 3 arranged on this bottom layer has however a lower oil penetration speed, which means that the top layer 3 exhibits a lower permeability compared to the bottom layer 2. The layers 2 and 3 are connected to each other by a lamination process.

[0022] The top layer 3 here has pores 4, which are formed by way of a laser perforation process. This laser perforation process occurs here independent from the actual production process of the wet friction lining 1. With the laser perforation method the patterns of the pores 4, the pore size, and also the pore depth are adjustable. In the present case the pores 4 penetrate the entire top layer 3. The layer thickness of the top layer 3 and the pore density can here be adjusted precisely and depending on the application process, exactly adjusting the hydraulic faceplate effect of the top layer 3 and thus the oil delivery from the bottom layer 2 to the environment of the clutch due to the pressure of the wet friction layer 1 applied.

[0023] In a particularly beneficial production process the bottom layer 2 and the top layer 3 form a paper composite. These two layers, 2 and 3 are produced in a paper production process and laminated or directly connected to each other during the paper production process. After the completion of the wet friction layer 1 here pores 4 are entered into the top layer 3 by way of laser perforation. Using the laser perforation a wide range of perforation diameters can be yielded from 50 nm to 500 m. The aperture sequence yielded within one second during the laser perforation process ranges from 1.5 to 16 million pores. This is possible at a pore density up to 500 pores per cm.sup.2.

[0024] Alternatively it is also possible that the bottom layer 2 and the top layer 3 are produced independent from each other, with the top layer 3 initially being provided with pores 4 by way of laser perforation and subsequently applied on the bottom layer 2 by way of lamination or via a separate adhesive layer.

[0025] In another embodiment the top layer 3 of the wet friction lining 1 may be provided with a closed surface, which is possible e.g., by a calendaring process. Subsequently the opening of the surface of the top layer 3 occurs by way of laser perforation. In laser perforation the pore depth can be set to different depths. They may here penetrate the top layer 3 only partially or completely as already described. However, the option is also given that the pore depth penetrates to the bottom paper.

[0026] The method explained is however not limited to a laser perforation method. For example, mechanical perforation methods can also be performed, such as a hot-needle or cold-needle perforation methods.

[0027] Furthermore, electrostatic micro-perforation or nano-perforation can be applied over the entire area or over certain zones, with here the diameter of the apertures that can be realized may range from 0.1 to 3000 m for the pores 4. By developments in the framing topology for the generation of very fine, power-controlled high-voltage discharge pulses with short durations ranging from 0.5 to 20 s and individual charge energy from 0.2 to 1 mJ nano-technology can be used for sub-micro perforation in this range.

LIST OF REFERENCE CHARACTERS

[0028] 1 wet friction lining

[0029] 2 bottom layer

[0030] 3 top layer

[0031] 4 pores