Cooled tool for hot-forming and/or press-hardening of a sheet metal material and method for producing a cooling device for this tool

Abstract

The invention relates to a tool for hot-tanning and/or press hardening of a sheet metal material, this tool having a plurality of cooling devices through which a coolant can flow, in order thus to be able to actively cool at least regions of the effective tool surfaces which come into contact with the sheet metal material. According to the invention, at least one cooling device comprises a shell element having an effective tool surface, wherein this shell element has, on its rear side facing away from the effective tool surface, a plurality of separate cooling chambers, through which a coolant can flow, and arranged in each of these cooling chambers is at least one flow guiding element for the coolant. The invention also relates to a method for producing such a cooling device for this tool.

Claims

1. A tool for hot-forming and/or press-hardening of a sheet-metal material, the tool comprising: a base; and multiple cooling devices through which coolant flows to cool active tool surfaces in direct contact with the sheet-metal material, at least one of the multiple cooling devices comprising: a shell element having an a contoured active tool surface section, wherein the shell element defines a plurality of separate cooling chambers opposite the active tool surface section, wherein the shell element is configured to be removably attached to the base; and a flow guide, comprising: a plurality of non-hollow flow guide elements, each disposed in a corresponding one of each of the cooling chambers, and a rail connecting each of the flow guide elements so as to form a unitary structure therewith, wherein the shell element and a circumferential outer contour of the flow guide element defines a gap within the cooling chamber through which the coolant flows to cool that active tool surface in direct contact with the sheet metal, wherein the cooling chambers are structured to form an essentially uniform wall thickness over the course of the contoured active tool surface, wherein two adjacent cooling chambers, of the plurality of separate cooling chambers, are divided by a support rib disposed between them, wherein the rail is configured to be coupled and decoupled to the shell element, and wherein each of the non-hollow flow guide elements is configured to be removable from corresponding cooling chambers via decoupling of the rail from the shell element subsequent to removal of the shell element from the base.

2. The tool according to claim 1, wherein at least one flow guide element is configured as a one-piece flow guide body.

3. The tool according to claim 2, wherein the flow guide body is formed from a plastic material or from a composite plastic material.

4. The tool according to claim 2, wherein the flow guide body is formed from an aluminum material.

5. The tool according to claim 1, wherein the shell element is a cast metal part.

6. The tool according to claim 1, wherein the tool comprises a lower tool part and an upper tool part, wherein opposite ones of the multiple cooling devices are situated in the lower tool part and in the upper tool part, respectively, the cooling chambers of such devices being disposed offset relative to one another.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows, in a sectional view, a lower tool part belonging to a tool according to the invention.

(2) FIG. 2 shows a section through the lower tool part from FIG. 1, along the section course indicated.

(3) FIG. 3 shows an alternative embodiment possibility, in the same representation as FIG. 2.

DETAILED DESCRIPTION OF THE DRAWINGS

(4) FIG. 1 shows a lower tool part 100 that belongs to a press-hardening tool (where a hot-forming tool can have an essentially identical structure). The upper tool part 200 that belongs to the press-hardening tool, which can fundamentally have the identical structure as the lower tool part 100, is only indicated schematically. The tool parts 100 and 200 have active tool surfaces 120 and 220, between which a heated sheet-metal material can be shaped and, at the same time, cooled. The lower tool part 100 has multiple cooling devices, in order to be able to actively cool the tool surface 120 that comes into direct contact with the heated sheet-metal material. The upper tool part 200 also has such cooling devices.

(5) These cooling devices include metallic shell elements 130 and 140 that are interchangeably attached to a basic tool body 110. In the following, the left-side cooling device will be explained in greater detail, for which purpose the shell element 140 is shown in a sectional view. The right-side cooling device with the shell element 130 is structured in comparable manner. Instead of two or more cooling devices having shell elements, only one cooling device having a shell element can also be provided on the tool according to the invention. Likewise, supplementally, other cooling devices or cooling systems known from the state of the art (for example conventional cooling bores or cooling channels) can also be provided on the tool according to the invention.

(6) The shell element 140 has an active tool surface section 120. Proceeding from the rear side, facing away from the active tool surface section 120, which side lies on the base body 110, multiple cooling chambers 141 extend into the shell element 140, through which chambers a cooling medium (particularly water) can flow. Each cooling chamber 141 has separate flow through it, where the inflows and outflows for the coolant that lead by way of the basic tool body 110 are not shown. The cooling chambers 141 that are adjacent to one another are divided by means of support ribs 142, where the support ribs 142 support themselves on the planar basic tool body 110 (which is shown merely as an example), thereby improving the pressure strength and the setting behavior of the shell element 140 and leading to an increase in the useful lifetime.

(7) The cooling chambers 141 have an individual shaping and a different depth (and thereby a different volume), taking the structure of the active tool surface section 120 into consideration, where the respective depth is dimensioned in such a manner that an equal thickness distance (shell thickness) relative to the active tool surface section 120 occurs at the bottom of the recesses or cooling chambers 141, as shown. To state it in other words, this means that the cooling chambers 141 are structured close to the contour with reference to the active tool surface section 120, so that almost uniform wall thicknesses (shell thicknesses) occur over the course of the contour of the active tool surface section 120, in order to thereby achieve uniform cooling of the active tool surface section 120. However, it is also possible to obtain an individual precision adjustment of the cooling properties (particularly for adaptation of the component properties) by means of different wall thicknesses or shell thicknesses that can be implemented relatively easily. The shell thicknesses in the region of the active tool surface section 120 can be kept very low, on the basis of the support provided by the support ribs 142, and this is advantageous for cooling of the active tool surface section 120. Because of the support provided by the support ribs 142, the shell element can also be configured with great hardness in the region of the active tool surface section 120.

(8) It is provided that a core-like flow guide element 143 is disposed in each cooling chamber 141. The flow guide element 143 serves to guide the coolant through the cooling chamber 141 in defined manner, as will be explained in greater detail below. The flow guide element is a one-piece body (referred to as a flow guide body hereinafter), composed of a plastic material (or of a metal material that can be worked easily, such as aluminum, for example). Fundamentally, however, a flow guide element or flow guide body 143 can also be configured in multiple parts. Each flow guide body 143 is adapted, in terms of its shaping, to the shaping of the related or corresponding cooling chamber 141. A rod-like or rail-like connection element is referred to as 147; all the flow guide bodies 143 inserted in the shell element 140 are attached to it (for example by means of a screw connection), thereby creating a structural unit that is easy to handle.

(9) FIG. 2 shows a section through the shell element 140, where this section passes through a cooling chamber 141 and the core-like flow guide body 143 inserted in it, according to the section course A-A indicated in FIG. 1. The one-piece flow guide body 143 is composed, with regard to its circumferential outer contour or circumferential contour, in such a manner that a flow gap 145 occurs between the flow guide body 143 and the opposite cooling chamber wall of the cooling chamber 141, through which gap the coolant can flow in defined manner (as illustrated with flow arrows), and thereby control of the coolant volume stream is achieved. The gap width of the flow gap 145 can be locally adapted as required, and this takes place by means of removal or application of plastic material on the flow guide body 143, if necessary. A flow channel or the like, for the coolant, can be worked into the circumferential circumference surfaces of the flow guide body 143.

(10) The flow guide body 143 can touch the chamber wall on the face side (as shown in FIG. 1). Preferably, however, it is provided that the shaping of the flow guide body 143 is composed, with reference to the shaping of the related or corresponding cooling chamber 141, in such a manner that a constantly wide or locally differently wide flow gap 145 exists at every location or everywhere, so that the flow guide body 143 can have the cooling medium flow around it completely, in other words also on the face side. In this way, overheating of the flow guide body 143 can be effectively prevented. The flow guide body 143 is attached to the rod-like connection element 147, and is held within the cooling chamber 141 in this way, and fixed in place in the position shown. The connection element 147 can be screwed onto the shell element 140.

(11) The upper tool part 200, which is shown only schematically in FIG. 1, can be structured in a manner comparable to that of the lower tool part 100. The cooling chambers 141 in the shell element 140 that belongs to the lower tool part 100, and the cooling chambers 241 in an opposite shell element on the upper tool part 200 are disposed offset, so that no heat nests can occur as the result of possibly insufficient cooling of the active tool surfaces 120 and 220. The offset of the cooling chambers 241 in the upper tool part 200 and of the cooling chambers 141 in the lower tool part 100 is particularly structured in such a manner that the cooling chambers of the one tool part are covered by the support ribs between the cooling chambers of the other tool part (when the tool is closed).

(12) The cooling device described above can be produced in relatively simple, cost-advantageous, and rapid manner. The shell element 140 can be produced as a one-piece milled metal part or as a cast metal part. (If necessary, a multi-piece welded construction is also possible.) Without complicated working of the cooling chamber walls (inner walls), a liquid plastic or metal material can subsequently be cast into the cooling chambers 141, in order to thereby produce the flow guide bodies 143. For easier unmolding and/or for adjusting the flow gap 145, the cooling chambers 141 can be coated with a parting agent (or the like) or lined with a film (for example a wax film) before casting. Furthermore, pull-out bevels can be provided. After hardening or solidification, the flow guide bodies 143, particularly solid bodies, can be removed from the cooling chambers 141 and reworked, if necessary (this preferably takes place manually), where reworking of a plastic material (or aluminum material) particularly proves to be very simple, because of the weight and the material properties. The flow gap 145 between a flow guide body 143 and a related cooling chamber wall (which particularly remains unworked) can be set merely by means of working of the flow guide body 143.

(13) Ideally, the cooling chambers 141 are already prepared or pretreated before casting, in such a manner that optimal flow gaps 145 already occur without reworking of the flow guide bodies 143. The flow guide bodies 143 can be attached to the shell element by way of the holder strip or holder rail 147, and fixed in their position.

(14) FIG. 3 shows an alternative embodiment possibility of a cooling device according to the invention in the same representation as in FIG. 2. The same components are named with the same reference symbols. For differentiation, however, the letter a is supplementally used.

(15) In the embodiment possibility shown in FIG. 3, a plurality of flow fins 148a is provided instead of a one-piece flow guide body as explained above in connection with FIGS. 1 and 2, in order to achieve control of the coolant volume stream in the cooling chamber 141a. The flow fins 148a can partly overlap. The flow fins 148a are produced from a metal material, for example, and are attached to a holder rail 149a (for example by means of welding). Alternatively, the flow fins 148a can also be produced from a plastic material. The fin structure is particularly suitable for small and/or narrow cooling chambers.

(16) The cooling devices described above can be used not only in heat-forming and press-hardening tools but also in other tools such as, for example, tools for the production of CFRP components. A tool according to the invention can be used, with slight modifications, for a wet-pressing process within the course of the production of CFRP components, where the cooling devices can be repurposed to act as an oil-operated or water-operated heating device.

REFERENCE SYMBOL LIST

(17) Cooled tool for hot-forming and/or press-hardening of a sheet-metal material, and method for the production of a cooling device for this tool

(18) 100 lower tool part 110 basic tool body 120 active tool surface 130 shell element 140 shell element 141 cooling chamber 142 support rib 143 flow guide body 145 flow gap 147 holder rail 148a flow fin 149a holder rail 200 upper tool part 220 active tool surface 241 cooling chamber

(19) The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.