Sheet metal working tool with draw cushion device and at least one gas spring with integrated generator device and gas spring with integrated generator device

Abstract

Sheet metal working tool (100) for forming and / or cutting a sheet metal material (400) by means of a press, with at least two tool parts (200, 300) between which the sheet metal material (400) can be formed and / or cut during a closing movement (S) generated on the side of the press, characterized by the fact that at least one of the tool parts (200) has a draw cushion device for actuating a sheet metal holder (230) displaced during the closing movement (S), wherein the drawing cushion device has at least one gas spring (250B) for applying force and resetting the sheet metal holder (230), wherein the gas spring (250B) has an integrated generator device (258) which, during the closing movement (S), can convert a portion of the kinetic energy applied on the press side for the displacement of the sheet metal holder (230) into usable electrical energy.

Description

[0001] According to the preamble of claim 1, the invention relates to a sheet metal working tool for forming and / or cutting sheet metal material using a press. Such a sheet metal working tool can also be referred to as a press-mounted sheet metal working tool. It is provided that this sheet metal working tool has at least one integrated draw cushion device for actuating a sheet metal holder.

[0002] The invention further relates, according to the preamble of claim 6, to a gas spring for use in the sheet metal working tool.

[0003] Sheet metal working tools of the type in question are known from the prior art. These tools typically comprise several tool parts that are movable relative to one another. During a closing movement generated by the press, the sheet metal material to be processed can be formed and / or cut between these tool parts. The tool parts are, in particular, an upper tool part and a lower tool part, the upper tool part being attached to a press ram and the lower tool part being mounted on a press table. Lowering the press ram closes the sheet metal working tool, with the closing movement and the associated closing force simultaneously serving to form and / or cut the sheet metal material located between the tool parts.

[0004] A draw cushion (also referred to herein as a draw cushion device) integrated into the sheet metal working tool allows the sheet metal material to be clamped in a known manner by means of a sheet metal holder or the like during forming and / or cutting. A draw cushion or draw cushion device is understood to be a mechanism that enables the sheet metal holder to be displaced during the closing movement, thereby exerting a force on at least one area of ​​the sheet metal material.

[0005] When the die holder is displaced, work (displacement work) is expended, which is mostly converted into heat. Especially with high-speed presses (e.g., with more than 20 and particularly more than 25 strokes per minute), the generated heat is sometimes so high that it must be dissipated from the sheet metal working tool. Therefore, additional cooling devices such as cooling units are often necessary.

[0006] From the nearest patent application, DE 10 2006 058 630 A1, an electro-hydraulic draw cushion drive is known, which has a controllable electric motor that can also be operated as a generator. As soon as the upper tool has made contact with the sheet metal, it begins to press the draw cushion downwards. The torque of the electric motor is reversed – it now operates as a generator and brakes the draw cushion.

[0007] For the state of the art, reference is also made to DE 10 2004 030 678 A1, DE 199 54 310 A1 and DE 10 2010 019 324 A1.

[0008] The object of the invention is to demonstrate new possibilities in the design of a sheet metal working tool of the type in question, in order to avoid or at least reduce the disadvantages associated with the prior art.

[0009] The object of the invention is solved by a sheet metal working tool with the features of claim 1. Preferred further developments and embodiments result both from the claims dependent on claim 1 and from the following explanations.

[0010] The object of the invention is also solved by a gas spring with the features of claim 6.

[0011] The following explanations apply analogously to both inventions. This applies in particular to the described further developments and embodiments.

[0012] The sheet metal working tool according to the invention for forming and / or cutting sheet metal material by means of a press comprises at least two tool parts, in particular an upper tool part attached to the press ram and a lower tool part attached to the press table, which are movable relative to each other and between which the sheet metal material to be processed can be formed and / or cut during a closing movement generated by the press. At least one of the tool parts has a draw cushion device for actuating a sheet metal holder displaced during the closing movement, wherein it is provided that this draw cushion device comprises at least one generator device, as explained in more detail below, which converts a portion of the kinetic energy or displacement work applied by the press for displacing the sheet metal holder into usable electrical energy during the closing movement.can convert.

[0013] A generator device is understood here to be a device that converts or can convert kinetic energy and / or a mechanical force into electrical energy, whereby this electrical energy can be tapped and used in almost any way.

[0014] By converting a portion of the displacement work performed by the press into electrical energy using at least one generator device within the sheet metal working tool according to the invention, heat generation in the sheet metal working tool is very low. This eliminates the need for additional cooling devices. Furthermore, it offers a space advantage, as the generator device in the sheet metal working tool requires less space than a cooling device. The connection effort is also significantly lower for a generator device than for a cooling device.

[0015] A significant advantage, however, lies in the fact that the displacement work expended by the press can now be at least partially recovered as electrical energy, which occurs within the sheet metal working tool and thus largely independently of the press. Previously, the displacement work converted into heat within the sheet metal working tool not only remained unused but also required additional energy for cooling. With the sheet metal working tool according to the invention, the overall energy efficiency of the forming and / or cutting process is thus significantly improved, which also brings economic advantages.

[0016] According to the invention, the drawing cushion device comprises at least one spring device for applying force and resetting the sheet metal holder, which is well known from the prior art, wherein this spring device is a gas spring. Gas springs are mostly standard components and / or standard parts that are available in a wide variety of designs.

[0017] According to the invention, the generator device is integrated into a spring assembly designed as a gas spring. That is, the gas spring for applying force and resetting the sheet metal holder comprises a structurally integrated generator device. The integrated generator device can, for example, be at least one piezoelectric element. Preferably, however, the integrated generator device is a dynamo or alternator. A dynamo is a mechanically driven device that can convert mechanical energy (kinetic energy) into electrical energy.

[0018] In particular, it is provided that the spring assembly, designed as a gas spring, further comprises an integrated mechanical converter stage or gearbox, which is mechanically connected upstream of the dynamo and which translates the linear movement of the sheet metal holder during the closing movement in order to achieve an adaptation to the dynamo with regard to force or displacement. Specifically, it is provided that the converter stage transforms the linear movement of the sheet metal holder during the closing movement into a rotary movement to drive the dynamo, which can be achieved, for example, by means of a conversion mechanism similar to that of a spinning top or a drill.

[0019] Furthermore, it is preferably provided that the gas spring with the integrated generator device is designed and / or integrated into the sheet metal working tool in such a way that electrical energy is generated only when the sheet metal holder is displaced (i.e., during the closing movement) and that no electrical energy is generated when the sheet metal holder is returned to its original position (i.e., during the opening movement). The mechanical return of the sheet metal holder to its initial position can thus occur unhindered by any influences from energy conversion into electrical energy. During this period, however, the current generation can optionally be maintained by means of a flywheel, as explained in more detail below.

[0020] The object of the invention is also achieved by a gas spring intended for use in a sheet metal working tool according to the invention, comprising the features of claim 6. This gas spring is provided to have an integrated generator device which, during compression (and in particular only during compression), converts the externally applied kinetic energy or pressing force into usable electrical energy. Preferably, this gas spring is equipped with a freewheel function for the integrated generator device, which allows the gas spring to return to its resting position without generating electrical energy. Such a freewheel function can be implemented, for example, with a clutch or the like. Furthermore, the gas spring can have a flywheel that is coupled or can be coupled to the generator device.

[0021] The electrical energy generated by a sheet metal working tool and / or a gas spring according to the invention can be used to charge electrical energy storage devices and / or to operate auxiliary devices on the sheet metal working tool and / or on the press according to the invention. An electrical energy storage device could be, for example, the battery of a forklift truck that is moved in the vicinity of the press. Auxiliary devices could be, for example, lighting elements in the tool and / or on the press.

[0022] The invention is explained in more detail below by way of example and in a non-restrictive manner with reference to the single figure.

[0023] The figure shows a schematic sectional view of a section of a sheet metal working tool according to the invention, which is, by way of example, a simple deep drawing tool (forming tool).

[0024] The sheet metal working tool 100 comprises a lower tool part 200 and an upper tool part 300, shown only schematically. The lower tool part 200 rests on a press table (not shown). The upper tool part 300 is attached to a press ram (not shown) and can be moved vertically together with the press ram.

[0025] The tool base 200 comprises a base plate 210 on which a rigid forming die 220 is mounted. Reference numeral 230 designates a sheet metal holder, which is supported on the base plate 210 by several gas springs 250A and 250B. The gas springs 250A and 250B belong to a draw cushion or a draw cushion assembly for actuating the sheet metal holder 230.

[0026] By closing the sheet metal working tool 100, which is achieved by lowering the upper tool part 300 on the press side (see arrow S), the sheet metal material 400 located between the tool parts 200 and 300 can be formed, whereby the sheet metal material 400 is pressed against the upper tool part 300 by the sheet metal holder 230 in a known manner. Simultaneously with the closing movement S or downward movement of the upper tool part 300, the sheet metal holder 230 is displaced downwards against the force exerted by the gas springs 250A and 250B, whereby the piston rods 255 of the gas springs 250A and 250B are pressed into the gas spring housings (see arrows K). In this process, the gas springs 250A and 250B are compressed. The force or energy for this is applied by the press in which the tool 100 is installed.

[0027] It is provided that the drawing cushion device includes at least one generator device which, during the closing movement S, can convert a portion of the kinetic energy applied on the press side for the displacement of the sheet metal holder 230 (which can also be referred to as displacement work) into usable electrical energy.

[0028] This could be achieved, for example (not according to the invention), by arranging a piezoelectric element 260 between the gas spring 250A and the base plate 210. When the sheet metal working tool 100 closes, the piezoelectric element 260 is integrated into the force flow from the base plate 210 through the gas spring 250A to the sheet metal holder 230. The electrical energy generated in the piezoelectric element 260 can be tapped off and used, for example, as a DC voltage at terminals, which is only shown schematically in the figure. The closing movement S is completed at the latest when the press ram, together with the upper part of the tool 300, has reached its bottom dead center.

[0029] According to the invention, a generator device 258 is integrated into the gas spring 250B. The electrical energy generated in this integrated generator device 258 can, for example, be tapped off at terminals in the form of a DC voltage and then used, as shown schematically in the figure.

[0030] The generator device 258 can be a dynamo driven by a converter stage or by a gearbox, which transmits the compression movement K of the piston rod 255 to the dynamo with or without a gear reduction. Preferably, the gas spring 250B has a freewheel function for the generator device 258 or for the dynamo, so that when the sheet metal working tool 100 opens, i.e., when the sheet metal holder 230 is moved upwards by the gas spring 250B, no energy conversion takes place in the integrated generator or in the generator device 258. This can be achieved, for example, by a clutch that only allows mechanical transmission from the piston rod 255 to the generator device 258 or the dynamo when the gas spring 250B is compressed by pushing or pressing the piston rod 255 into the gas spring housing.

[0031] Furthermore, it may be provided that a flywheel or similar device is coupled to the generator device 258 or the dynamo, or at least can be optionally coupled. This can serve various functions. For example, the flywheel can be used to maintain a continuous generation of electrical energy, thus ensuring, for instance, that usable electrical energy is available even when the sheet metal working tool 100 is opening, thereby guaranteeing smooth continuous operation of the generator device 258 or the dynamo independent of the press stroke. The flywheel can also be used to accelerate the generator or the dynamo at the beginning of the sheet metal holder displacement during the closing movement S in order to compensate for inertial effects.

[0032] In the sheet metal working tool 100 shown in the figure, the draw cushion device is arranged in the stationary lower tool part 200. However, the draw cushion device, including a generator device 258, could also be arranged in the upper tool part 300. Reference symbol list 100 sheet metal working tools (deep drawing tools) 200 tool base 210 Base plate 220 forming dies 230 sheet metal holders 250A gas spring 250B Gas spring 255 Piston rod 258 Generator device 260 piezoelectric elements 300 tool top 400 sheet metal S Closing movement K compression movement

Claims

Sheet metal working tool (100) for forming and / or cutting a sheet metal material (400) by means of a press, with at least two tool parts (200, 300) between which the sheet metal material (400) can be formed and / or cut during a closing movement (S) generated on the side of the press, characterized in that at least one of the tool parts (200) has a draw cushion device for actuating a sheet metal holder (230) displaced during the closing movement (S), wherein the draw cushion device has at least one gas spring (250B) for applying force and resetting the sheet metal holder (230), wherein the gas spring (250B) has an integrated generator device (258) which can convert a portion of the kinetic energy applied on the side of the press for the displacement of the sheet metal holder (230) into usable electrical energy during the closing movement (S). Sheet metal working tool (100) according to claim 1, characterized in that the integrated generator device (258) is a dynamo. Sheet metal working tool (100) according to claim 2, characterized in that a mechanical converter stage is provided upstream of this dynamo, which translates the linear movement of the sheet metal holder (230) during the closing movement (S). Sheet metal working tool (100) according to claim 3, characterized in that the converter stage converts the linear movement of the sheet metal holder (230) during the closing movement (S) into a rotary movement to drive the dynamo. Sheet metal working tool (100) according to one of the preceding claims, characterized in that the gas spring (250B) with the integrated generator device (258) is designed such that electrical energy is generated only when the sheet metal holder (230) is displaced and that no electrical energy is generated when the sheet metal holder (230) is reset. Gas spring (250B) for use in a sheet metal working tool (100) according to one of the preceding claims, characterized in that this gas spring (250B) has an integrated generator device (258) which, when compressed, can convert the externally applied kinetic energy into usable electrical energy. Gas spring (250B) according to claim 6, characterized in that it is equipped with a freewheel function for the integrated generator device (258) which enables a reset without generating electrical energy.

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