Metal sheet with contour cut for vibration reduction

Abstract

A metal sheet with attachment points for attaching the metal sheet to a support structure has a contour cut introduced in a sheet surface of the metal sheet, wherein the contour cut extends transversely to a connection line extending between a first and a second one of the attachment points. The contour cut is positioned relative to the first attachment point such that a vibration line extending as far as the first attachment point when the contour cut is not present is interrupted by the contour cut.

Claims

1. A metal sheet (2) comprising attachment points (4) configured to attach the metal sheet (2) to a support structure (12), the metal sheet (2) further comprising a contour cut (14) introduced in a sheet surface of the metal sheet (2), wherein the contour cut (14) extends transversely to a connection line (24) extending between a first and a second one of the attachment points (4), wherein the contour cut (14) that is positioned along the connection line (24) is located adjacent to the first attachment point (4) such that a vibration line that would extend as far as the first attachment point (4) if the contour cut (14) were not present is interrupted by the contour cut (14), wherein the contour cut (14) is arranged in an area of stress transition from the first attachment point (4) to the freely vibrating sheet, wherein the area of stress transition extends up to 16 mm away from the first attachment point (4).

2. The metal sheet (2) according to claim 1, wherein the contour cut (14) comprises opposed ends (18) in a direction transverse to the connection line (24) and the ends (18) open into cut lines (16) extending in an arc shape around the ends (18) toward the connection line (24), respectively.

3. The metal sheet (2) according to claim 1, wherein the metal sheet (2) is a perforated sheet.

4. The metal sheet (2) according to claim 1, wherein the attachment points (4) and the contour cut (14) are arranged in the area of the outer edge (22) of the metal sheet (2).

5. The metal sheet (2) according to claim 1, further comprising relieving cuts in the sheet surface.

6. The metal sheet (2) according to claim 1, wherein the metal sheet (2) consists of metal and wherein the contour cut (14) passes all the way through a thickness of the metal sheet (2).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention shall now be explained more closely with the aid of a preferred exemplary embodiment and with reference to the enclosed drawings.

(2) FIG. 1 shows a cutout view of a perforated sheet with a contour cut in an attachment point.

(3) FIG. 2 shows a view of a metal sheet with outer edge, in which the attachment points and the contour cuts are arranged.

(4) FIG. 3 is a graph showing how the stiffness gradient is altered by making a contour cut in a metal sheet.

DESCRIPTION OF PREFERRED EMBODIMENTS

(5) FIG. 1 shows a view of a metal sheet 2, being configured in the exemplary embodiment as a perforated sheet. The metal sheet 2 is joined by an attachment point 4 to a support structure 12. The connection is produced in the exemplary embodiment by a screw 6, which is joined to the support structure 12. For the joining of the metal sheet 2 to the support structure 12, a screw nut 8 with a washer 10 underneath is screwed onto the screw 6. By this connection, the metal sheet 2 is firmly held in the support structure 12.

(6) Besides the attachment point represented in FIG. 1, the metal sheet 2 is further joined by at least one additional attachment point 4 to the support structure 12. The metal sheet 2 is thus secured in its installation position at least at two points.

(7) Adjacent to the attachment point 4 there is a contour cut 14 in the metal sheet 2. The contour cut 14 is an incision in the metal sheet 2 extending transversely to a connection line 24 indicated by broken lines to a further attachment point 4. At the ends 18 the contour cut 14 emerges respectively in an arc-shaped cut line 16, which is traced respectively in an arc-shaped manner around the ends 18 toward the connection line 24.

(8) The metal sheet 2 can be excited to vibrate in the planes F.sub.x, F.sub.y and F.sub.z. If the metal sheet 2 is vibrating for example in a vibration line corresponding to the arrow direction F.sub.z, the metal sheet 2 will perform vibrations in the direction of the arrow F.sub.x. If the surface of the metal sheet 2 vibrates along the vibration line running parallel to the connection line 24, the corresponding vibration movements from the sheet surface will end at the contour cut 14. Thus, they cannot continue across the contour cut 14 to the attachment point 4. On the other hand, vibration movements which are transmitted from the support structure 12 across the attachment point 4 to the metal sheet 2 are not directly transmitted along the connection line 24 to the metal sheet 2, but instead remain stuck in the contour cut 14, starting from the attachment point 4.

(9) In order to prevent the contour cut 14 from being lengthened at its ends 18 by crack formation as a consequence of the lines of force acting at its ends 18, the contour cut 14 emerges at the two opposite ends 18 into arc-shaped cut lines 16, which also provide static relief for the lateral surrounding region of the contour cut 14 in the area of the ends 18. This prevents the contour cut 14 from being lengthened beyond the ends 18 and digging in further under vibrational loading.

(10) Since no holding forces can be transmitted between the attachment point 4 and the adjacent sheet blank across the contour cut 14, the lines of force for the fixation of the position and the supporting of the metal sheet 2 flow around the line of the contour cut 14 and around the two arcs of the cut line 16. There is still adequately broad and thick sheet material of the metal sheet 2 present here to introduce adequate holding forces into the metal sheet 2.

(11) FIG. 2 shows one embodiment of a metal sheet 2 in the form of a perforated sheet. The perforation pattern 20 of the perforated sheet is only indicated in the small rectangle.

(12) In FIG. 2, two connection lines 24 are indicated by broken lines, by which one attachment point 4 on the right side of the metal sheet 2 is connected to two attachment points 4, which are situated on the opposite side of the metal sheet 2. The connection lines 24 show that these always run across the contour cuts 14.

(13) The metal sheet 2 has an outer edge 22 in which all the attachment points 4 as well as the corresponding contour cuts 14 in the exemplary embodiment are arranged. In this way, the large sheet surface inside the outer edge 22 in the exemplary embodiment may be used as a ventilation surface of a cover grille of the radiator of a motor vehicle.

(14) FIG. 3 shows a graph in which the function 26 shows how the stiffness gradient in a metal sheet 2 behaves in dependence on the distance from an attachment point 4 before the contour cut 14 has been made in the metal sheet 2. The stiffness gradient in the region between two and three millimeters distance from the attachment point 4 has a very steep curve, after which at increasing distance it settles down at a constant level. By contrast with this, the stiffness gradient after making the contour cut 14 has a significantly flatter curve, shown with the aid of the function 28. Here, the stiffness of the sheet attains the stiffness level of the metal sheet 2 before making the contour cut 14 only at a distance of around fourteen millimeters, while this stiffness level without the contour cut 14 was attained already at a distance of around three millimeters. Owing to the contour cut 14, therefore, the stiffness gradient becomes increasingly flat due to the increasing distance from the attachment point 4.

(15) The invention is not limited to the above exemplary embodiment. It will present the skilled person with no difficulties to modify the exemplary embodiment in a way that appears suitable to him in order to adapt it to a specific application.