Noise Damping Fiber With Surface Grooves

Abstract

A noise damping fiber for a noise damper for compressed air systems, in particular for brake systems of utility vehicles, has surface grooves formed by surface treatment. A method for producing a noise damping fiber mesh, includes the steps of: forming thermoplastic fibers by a molding tool or an extruding tool; surface treating of the fibers by the molding tool, the extruding tool, or another tool configured to treat the surface of thermoplastic fibers; and knitting, braiding or weaving a plurality of the surfaced treated fibers into a noise damping fiber mesh.

Claims

1-12. (canceled)

13. A fiber for a noise damper of a compressed air system, comprising: a noise damping fiber of the noise damper, wherein the noise damping fiber comprises surface grooves formed by surface treatment.

14. The fiber according to claim 13, wherein a treated surface of the fiber has fringes and/or burrs.

15. The fiber according to claim 13, wherein the fiber is made of a thermoplastic.

16. The fiber according to claim 13, wherein a surface roughness of the fiber is at least 10 m.

17. The fiber according to claim 16, wherein the surface roughness of the fiber is in a range of 10 m to 40 m10%.

18. The fiber according to claim 16, wherein the surface roughness of the fiber is at least twice as high after said surface treatment compared to before said surface treatment.

19. The fiber according to claim 14, wherein a length of the fringes and/or burrs of the fiber is at least 0.05 mm.

20. The fiber according to claim 19, wherein the length of the fringes and/or burrs of the fiber is in the range of 0.05 to 10 mm.

21. The fiber according to claim 13, wherein a cross section of the fiber is rectangular, elliptical or circular.

22. A fiber mesh, comprising: a plurality of noise damping fibers knitted, braided or woven into the fiber mesh, wherein the plurality of noise damping fibers have surface grooves formed by surface treatment.

23. The fiber mesh according to claim 22, wherein a treated surface of the fiber has fringes and/or burrs.

24. The fiber mesh according to claim 22, wherein the fiber is made of a thermoplastic.

25. The fiber mesh according to claim 22, wherein a surface roughness of the fiber is in a range of 10 m to 40 m10%.

26. A component for a compressed air system, comprising: a fiber mesh according to claim 22; and a noise damper comprising the fiber mesh.

27. A method for producing a noise damping fiber mesh, the method comprising the steps of: forming thermoplastic fibers by a molding tool or an extruding tool; surface treating the fibers by the molding tool, the extruding tool, or another tool configured to treat a surface of thermoplastic fibers; and knitting, braiding or weaving a plurality of the surfaced treated fibers into the noise damping fiber mesh.

28. The method according to claim 27, wherein the treated surface of the fiber has fringes and/or burrs.

29. The method according to claim 27, wherein the fiber is made of a thermoplastic.

30. The method according to claim 27, wherein a treated surface roughness of the fiber is in a range of 10 m to 40 m10%.

31. The method according to claim 27, wherein a treated surface roughness of the fiber is at least twice as high after said surface treatment compared to before said surface treatment.

32. The method according to claim 28, wherein a length of the fringes and/or burrs of the fiber is in the range of 0.05 to 10 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG. 1 is a schematic perspective view of a noise damping fiber of the prior art;

[0031] FIG. 2 is a top view of the noise damping fiber of FIG. 1;

[0032] FIG. 3 is a schematic perspective view of a first embodiment of a noise damping fiber according to the present invention;

[0033] FIG. 4 is a top view of a second embodiment of the noise damping fiber according to the present invention;

[0034] FIG. 5 is a top view of a third embodiment of the noise damping fiber according to the present invention;

[0035] FIG. 6 is an embodiment of a method for producing a noise damping fiber mesh according to the present invention;

[0036] FIG. 7 is a schematic perspective view of a fourth embodiment of a noise damping fiber according to the present invention; and

[0037] FIG. 8 is a schematic perspective view of a fifth embodiment of a noise damping fiber according to the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0038] FIG. 1 shows a schematic perspective view of a noise damping fiber 10 of the prior art. The prior art fiber 10, made of a thermoplastic, has a smooth surface and a rectangular cross section. From FIG. 2 it can be understood that the fiber is flexible or bendable.

[0039] In FIG. 3, a schematic perspective view of a first embodiment of a noise damping fiber 100 according to the present invention is shown.

[0040] The fiber 100 has grooves 102, which are preferably lengthwise and continuous. The grooves 102 are arranged in a substantially parallel manner to each other. Other arrangements are also possible such as are shown in FIG. 7 and/or FIG. 8. The grooves are in the range of 10 to 40 m, in particular in the range of at least 10 m to 40 m10%.

[0041] The grooves 102 are inserted either after molding or extrusion or during molding or extrusion of the fiber.

[0042] The fiber 100 is made of a thermoplastic, which gives it flexibility or pliability.

[0043] The fiber 100 has a rectangular cross section 104. Other cross section shapes like a circle or ellipse are also possible.

[0044] In FIG. 4, a top view of second embodiment of the noise damping fiber 100 is shown.

[0045] The fiber 100 of FIG. 4 has also lengthwise, but sectionally interrupted grooves 102.

[0046] The shape or design of grooves 102 depends on the surface treatment process and/or tool.

[0047] The grooves 102 can also run crosswise to the longitudinal extension of the fiber 100 or in any other direction.

[0048] FIG. 5 shows a third embodiment of the noise damping fiber 100 according to the present invention.

[0049] The fiber 100 of FIG. 5 has, in addition to grooves 102, a plurality of fringes or burrs 106 which have not been removed after roughening the surface of the fiber 100.

[0050] Due to heterogeneous material composition, tolerances in fiber production and wear and tear on the surface treatment tools, the number, shape and distribution of the burrs 106 are non-uniform.

[0051] The burr 106 also prevents the noise from developing, just like the grooves 102.

[0052] In FIG. 6, an embodiment of a method 200 for producing a noise damping fiber mesh is presented.

[0053] The method 200 is suitable to produce noise damping fibers 100 and noise damping fiber mesh according to the present invention.

[0054] In a first method step 202, thermoplastic fibers are formed by a molding or an extruding tool. In other words, a thermoplastic feedstock is formed into fibers.

[0055] In a second method step 204, the thermoplastic fibers' surface is treated either by the molding tool, the extruding tool, or another tool configured to treat the surface of thermoplastic fibers. Surface treatment is to be understood as the roughening of the surface, wherein roughening can be achieved by brushing, thorns, rolling or the like.

[0056] The method 200 thus provides the fibers 100 described above.

[0057] In a third method step 206, a plurality of the fibers 100 is knitted, braided or

[0058] woven to form a noise damping fiber mesh which may be used in a noise damper for compressed air systems.

[0059] When comparing results of surface roughness comparison measurements of fibers from different suppliers, it has been determined that the surface treatment leads to a significant increase in surface roughness R.sub.z. The increase in surface roughness R.sub.z leads to a better absorption of airborne sound or noise, i.e. sound energy is converted into dissipative energy. Thus, the noise absorption efficiency is increased by the larger or expanded surface area of the fibers.

[0060] In particular, said measurements were performed on fibers already knitted to fiber mesh. Accordingly, the respective raw material, i.e. as delivered, may have a lower surface roughness R.sub.z, in particular compared to the material having been surface treated, e.g., roughened.

[0061] At least three measurements were carried out for each fiber type, wherein in addition to the values of the individual measurements, the average (avg.), minimum (min.) and maximum (max.) values in relation to the total of the at least three measurements of each fiber type were determined.

[0062] In this respect, it has been determined that a surface treatment according to the present invention results in a surface roughness of at least 10 m. Furthermore, it appears that in particular the average surface roughness R.sub.z after surface treatment is at least two times higher than that before the treatment.

[0063] In FIG. 7, a schematic perspective view of a fourth embodiment of a noise damping fiber 100 according to the present invention is shown.

[0064] The fiber 100 has grooves 102, which are preferably lengthwise and continuous. The grooves 102 are arranged in a substantially non-parallel manner to each other. The grooves are in the range of 10 to 40 m, in particular in the range of at least 10 m to 40 m10%.

[0065] The grooves 102 are inserted either after molding or extrusion or during molding or extrusion of the fiber.

[0066] The fiber 100 is made of a thermoplastic, which gives it flexibility or pliability.

[0067] The fiber 100 has a rectangular cross section 104. Other cross section shapes like a circle or ellipse are also conceivable.

[0068] In FIG. 8, a schematic perspective view of a fifth embodiment of a noise damping fiber 100 according to the present invention is shown.

[0069] The fiber 100 has grooves 102, which are substantially lengthwise and at least partly non-continuous. The grooves are in the range of 10 to 40 m, in particular in the range of at least 10 m to 40 m10%.

[0070] The grooves 102 are inserted either after molding or extrusion or during molding or extrusion of the fiber.

[0071] The fiber 100 is made of a thermoplastic, which gives it flexibility or pliability.

[0072] The fiber 100 has a rectangular cross section 104. Other cross section shapes like a circle or ellipse are also conceivable.

[0073] REFERENCE SIGNS

10 prior art noise damping fiber
100 noise damping fiber
102 grooves
104 cross section
106 fringe/burr
200 method for producing a noise damping fiber mesh
202 method step 1
204 method step 2
206 method step 3