Stamping press incorporating an energy recovery device

Abstract

The invention relates to a stamping press comprising a base having an upper receiving face, a lower die overhanging said upper receiving face, and an upper die carried by a plate mounted to slide vertically with respect to this base, said press also comprising a hydraulic energy recovery device (200) comprising: - a flexible membrane (220) filled with an incompressible liquid and arranged between said upper receiving face of the base and said lower die, - a hydraulic turbine (270), and: - an outlet pipe (260) fluidically connecting said membrane to the inlet of said turbine, said membrane being configured to be at least partially compressed by said lower die when said upper die is lowered against the latter so as to cause the extraction, via said outlet pipe (260),of a part of the liquid contained in said membrane and its displacement towards said hydraulic turbine. Figure to be published with the abstract: Fig. 2,

Description

Title of the invention: Stamping press incorporating an energy recovery device Technical field

[0001] The present invention relates, in general, to the field of stamping presses specially designed for deforming materials, generally metal sheets, in order to give them a specific shape. It relates in particular to such an energy recovery stamping press. Prior art

[0002] Stamping presses are widely used in the automotive industry for the manufacture of vehicle body parts with complex curved shapes such as door panels, hoods, fenders, roofs, tailgates, and other exterior components.

[0003] Such presses have a robust and often massive structure to withstand the significant forces generated during the stamping process. They can be of different types, such as mechanical, hydraulic or servo-electric presses.

[0004] Stamping is a process in which compressive forces are applied to a piece of sheet metal using an upper die and a lower die that slide relative to each other and sandwich the sheet to deform it and give it the desired profile.

[0005] In order to maximize energy efficiency, different solutions are known for exploiting the energy generated by these stamping presses.

[0006] Regenerative braking systems can thus be used to convert the kinetic energy generated during braking or slowing down of one of the dies into electrical energy that can be reinjected into the factory's electrical network.

[0007] Document EP 1 882 534 B1 proposes to convert the mechanical energy of the press into electrical energy, storing it for later use in the padding of the die during the pressing cycle in order to avoid deformation of the parts.

[0008] Energy storage devices, such as batteries or flywheels, can also be used to store the energy generated during the stamping process and converted into electrical energy using piezoelectric materials. This stored energy can be reused later by the press when needed or used by other machines.

[0009] The heating produced at each press stroke can also be recovered via a network of exchangers and then reinjected into heating equipment used, for example, in heating buildings.

[0010] These known energy recovery techniques unfortunately have certain limitations, particularly in terms of design and implementation costs, because they require relatively significant modifications to existing infrastructures and / or the use of expensive energy collection and conversion devices whose efficiency is relatively low. Statement of the invention

[0011] The present invention aims to improve the situation.

[0012] To this end, it proposes a stamping press comprising a base having an upper receiving face, a lower die overhanging said upper receiving face, and an upper die carried by a plate mounted to slide vertically with respect to this base; characterized in that it also comprises a hydraulic energy recovery device comprising: - a flexible membrane filled with an incompressible liquid and arranged between said upper receiving face of the base and said lower matrix, - a hydraulic turbine, and: - an outlet pipe fluidly connecting said membrane to the inlet of said turbine, said membrane being configured to be at least partially compressed by said lower die when lowering said upper die against the latter so as to cause the extraction, via said outlet pipe, of a portion of the liquid contained in said membrane and its movement towards said hydraulic turbine.

[0013] Such an energy recovery device has the advantage of being able to be easily integrated into a conventional stamping press without requiring significant structural modifications. Its energy efficiency is also higher than that of known devices since the recovered energy is transformed by the turbine into mechanical energy that can be used directly to ensure the operation of other types of devices such as a belt conveyor.

[0014] According to preferred characteristics of said stamping press according to the invention: - said energy recovery device comprises a reservoir located higher than said membrane and fluidically connected to the outlet of said hydraulic turbine by a connecting pipe so as to receive the liquid having passed through this turbine; - said energy recovery device comprises an inlet pipe fluidically connecting said reservoir to said membrane; - said inlet pipe is provided with a non-return valve authorizing circulation liquid only in the direction from said reservoir to said membrane; - said outlet pipe is provided with a non-return valve allowing the circulation of liquid only in the direction going from said membrane to said hydraulic turbine; - said energy recovery device comprises a rigid mat resting fixedly against said upper receiving face of the base, said mat defining a recess extending from its lower face and housing the main part of said membrane, the upper part of said mat extending above said recess having a plurality of holes crossed by hollow protrusions of said membrane fluidly connected to its main part, said protrusions projecting above said mat forming bubbles filled with liquid intended to be compressed by said lower die when said upper die is lowered against the latter; - said energy recovery device comprises elastic return means capable of holding said lower matrix, in the absence of compression forces exerted against it by said upper matrix, away from said belt so that its lower face is flush with the top of said bubbles without exerting any compression force on the latter; and / or - said protrusions and said holes are arranged regularly in rows and columns so as to form a grid.

[0015] The invention also aims, in a second aspect, at a subassembly comprising such a stamping press and a belt conveyor, said turbine comprising a rotor whose shaft is coupled to one of the turning rollers of said conveyor so as to ensure its drive.

[0016] According to an advantageous characteristic, the coupling between the shaft of the rotor of said turbine and that of said turning roller of the belt conveyor is ensured by means of a mechanical gear reducer so as to allow the forward speed of this conveyor to be adjusted. Brief description of the drawings

[0017] The description of the invention will now be continued by the detailed description of an exemplary embodiment, given below for illustrative but non-limiting purposes, with reference to the appended drawings, in which: - [Fig.l] represents a perspective view of a subassembly comprising a hydraulic energy recovery stamping press according to the invention coupled to a belt conveyor; - [Fig.2] is a perspective view of the hydraulic energy recovery device included in the stamping press of [Fig.l]; - [Fig.3] represents a perspective view from below of the mat and the matrix comprising the energy recovery device of [Fig.2]; - [Fig.4] is an enlarged sectional view of the belt and matrix of [Fig.3], taken at one of the orifices of this belt; - [Fig.5] and [Fig.6] represent elevation views of the stamping press of [Fig.l] illustrating the operation of the hydraulic energy recovery device of [Fig.2] during the lowering and raising phases of the upper die. Description of the embodiments

[0018] [Fig.l] represents a perspective view of a subassembly 1 comprising a hydraulic energy recovery stamping press 100 according to the invention coupled to a belt conveyor 300 whose operation is ensured thanks to the energy in hydraulic form recovered by this stamping press 100.

[0019] The stamping press 100 comprises a frame 110 composed of a parallelepiped-shaped base 111 resting on the ground and having an upper receiving face 11 1A (see figures 5 and 6), a head 112 extending above this base 111 in line with it, and four cylindrical guide uprights 113 extending vertically between the base 111 and the head 112 at their four corners.

[0020] A generally rectangular shaped plate 120 is mounted to slide vertically between the base 111 and the head 112 of this chassis 110 by means of four holes arranged at its four corners and crossed by the guide uprights 113.

[0021] The sliding movement of this plate 120 is for example ensured by hydraulic actuation means using a pressurized fluid to generate the force necessary for stamping.

[0022] As illustrated by [Fig.5], the lower receiving face 120A of this plate 120 carries an upper die 130 while a lower die 140 overhangs the upper receiving face 11 1A of the base 111.

[0023] According to the invention, the stamping press 100 also comprises a hydraulic energy recovery device 200 making it possible to operate the belt conveyor 300 intended to convey the metal sheets to be stamped to this press 100.

[0024] Shown alone in [Fig.2], this energy recovery device 200 comprises a rigid mat 210 made for example from a metallic material and resting fixedly against the upper receiving face 11 IA of the base 111 below the lower matrix 140.

[0025] As illustrated by [Fig.3], the mat 210 defines a recess 211 extending from its lower face and housing the main part 221 of a flexible membrane 220 filled with an incompressible liquid L such as water (see [Fig.4]).

[0026] With reference to figures 2 and 4, the upper part of this mat 210 extending above the recess 211 has a plurality of cylindrical holes 212 opening onto this recess 211.

[0027] This flexible membrane 220, thus arranged between the upper receiving face 11 IA of the base 111 and the lower matrix 140, also comprises several hollow protrusions 222 fluidly connected to its main part 221, these protrusions 222 passing through the holes 212 and projecting above the belt 210, forming bubbles 223 filled with liquid L.

[0028] As illustrated by [Fig.2], these protrusions 222 and these holes 212 are preferably arranged regularly in rows and columns so as to form a grid.

[0029] In order to facilitate the sliding of the protrusions 222 and the bubbles 223, the inner face and the peripheral periphery of these holes 212 are advantageously covered with an anti-friction coating 214 as shown in [Fig.4].

[0030] This coating 214 is preferably made of an elastomeric material in order to absorb any variations in size and shape of the bubbles 223, so as to guarantee uniform sliding of the protrusions 222 through the belt 210 during the operations of lowering and raising the upper die 130.

[0031] In order to avoid any risk of tearing during the compression phases, the membrane 220 is advantageously made of a thermoplastic elastomer, a silicone rubber, a polyurethane or even a flexible polymer. Its compressive strength can also be reinforced by the addition of natural and / or synthetic fibers such as glass or fabric fibers.

[0032] Its thickness will be chosen so as to offer an optimum compromise between mechanical resistance to compression and flexibility.

[0033] As illustrated by [Fig.6], in the absence of compressive forces exerted against it by the upper die 130, the lower die 140 is held by elastic return means 230 vertically away from the belt 210 so that its lower face is flush with the top of the bubbles 223 without exerting any compressive force on the latter.

[0034] These elastic return means are for example constituted by four helical compression springs 230 arranged vertically between the upper face of the belt 210 and the lower face of the lower matrix 140 at their corner zones.

[0035] Referring again to [Fig.2], the energy recovery device 200 also comprises: - an inlet pipe 240 in fluid communication by one of its ends with the main part 221 of the membrane 220 and the other end of which is fluidically connected to the lower part of a reservoir 250 located higher than this membrane 220; and - an outlet pipe 260 in fluid communication by one of its ends with the main part 221 of the membrane 220 and the other end of which is fluidically connected to the inlet of a hydraulic turbine 270.

[0036] The inlet pipe 240 is provided with a non-return valve 241 allowing the circulation of the liquid L only in the direction going from the reservoir 250 towards the membrane 220.

[0037] In the same way, the outlet pipe 260 is provided with a non-return valve 261 allowing the circulation of the liquid L only in the direction going from the membrane 220 towards the hydraulic turbine 270.

[0038] This hydraulic turbine 270, the outlet of which is fluidically connected to the upper part of the reservoir 250 via a connecting pipe 280, comprises an internal rotor with blades (not visible) whose shaft is coupled to one of the cylindrical turning rollers of the belt conveyor 300, so as to ensure its drive.

[0039] This coupling between the shaft of the turbine rotor 270 and that of the turning roller of the belt conveyor 300 is advantageously ensured by means of a mechanical gear reducer 290, so as to allow the forward speed of this conveyor 300 to be adjusted.

[0040] The operation of the energy recovery device 200 will now be briefly described using FIGS. 5 and 6.

[0041] When the sliding plate 120 carrying the upper die 130 is lowered by the actuating means of the press 100 to carry out the stamping of a sheet metal part not shown, the mechanical compression force undergone by the lower die 140 also causes it to be lowered against the elastic return means 230 so that its lower face crushes the bubbles 223 of the membrane 220 projecting above the belt 210 ([Fig.5]).

[0042] This crushing of the bubbles 223 has the consequence of causing the extraction, via the outlet pipe 260, of a part of the liquid L contained in this membrane 220 from the latter and its displacement in the direction of the hydraulic turbine 270, the rotor of which it will rotate so as to cause the advancement of the conveyor belt 300 (conversion of the hydraulic flow energy into rotation energy).

[0043] After passing through this hydraulic turbine 270, this liquid L then circulates in the connecting pipe 280 and flows into the reservoir 250.

[0044] It will be noted that the non-return valve 241 of the inlet pipe 240 prevents the liquid L to escape from the membrane 220 via this inlet pipe 240 during this bubble crushing phase 223.

[0045] Once the sheet metal part has been stamped, the sliding plate 120 carrying the upper die 130 is raised by the actuating means of the press 100 ( [Fig.6]). Actuated solely by the elastic return means 230, the lower die 140 returns to its raised rest position while the bubbles 223, no longer undergoing the compression of this lower die 140, also return to their initial position. The liquid L contained in the reservoir 250 will then naturally flow by gravity into the inlet pipe 240 and return to the membrane 220 so as to refill these bubbles 223.

[0046] It will be noted that the non-return valve 261 of the outlet pipe 260 prevents the liquid L from escaping from the turbine 270 to return to the membrane 220 via this outlet pipe 260 when the bubbles 223 return to their initial position.

[0047] At each stamping cycle, it is understood that the belt of the conveyor 300 will advance sequentially thanks to the energy recovery device 200 whose design and arrangement make it possible not to interfere with the trajectory of transfer robots not shown and ensuring the transport of the sheet metal part to be stamped between the press 100 and this conveyor 300.

[0048] According to alternative embodiments not shown, an energy storage mechanism, for example of the flywheel type, could be integrated into the energy recovery device 200 in order to ensure continuous movement of the conveyor belt 300.

[0049] According to other embodiment variants not shown, the energy recovered using the device 200 could be used to participate in or to fully ensure the energy supply of other types of devices.

[0050] The shape, dimensions and / or spacing of the bubbles may also be adjusted depending on the quantity of hydraulic energy that is to be recovered.

[0051] Numerous variants are conceivable and it is recalled in this regard that the present invention is not limited to the embodiments described and shown, but also encompasses all the variants of execution within the reach of those skilled in the art.

Claims

Claims

1. Stamping press (100) comprising a base (111) having an upper receiving face (11 IA), a lower die (140) overhanging said upper receiving face (11 IA), and an upper die (130) carried by a plate (120) mounted to slide vertically with respect to this base (111);characterized in that it also comprises a hydraulic energy recovery device (200) comprising: - a flexible membrane (220) filled with an incompressible liquid (L) and arranged between said upper receiving face (11 IA) of the base (111) and said lower die (140), - a hydraulic turbine (270), and: - an outlet pipe (260) fluidly connecting said membrane (220) to the inlet of said turbine (270), said membrane (220) being configured to be at least partially compressed by said lower die (140) when said upper die (130) is lowered against the latter so as to cause the extraction, via said outlet pipe (260), of a portion of the liquid (L) contained in said membrane (220) and its movement towards said hydraulic turbine (270).;

2. Stamping press (100) according to claim 1, characterized in that said energy recovery device (200) comprises a reservoir (250) located higher than said membrane (220) and fluidly connected to the outlet of said hydraulic turbine (270) by a connecting pipe (280) so as to receive the liquid (L) having passed through this turbine (270).

3. Stamping press (100) according to claim 2, characterized in that said energy recovery device (200) comprises an inlet pipe (240) fluidly connecting said reservoir (250) to said membrane (220).

4. Stamping press (100) according to claim 3, characterized in that said inlet pipe (240) is provided with a non-return valve (241) allowing the circulation of the liquid (L) only in the direction going from said reservoir (250) towards said membrane (220).

5. Stamping press (100) according to one of claims 1 to 4, characterized in that said outlet pipe (260) is provided with a non-return valve (261) allowing the circulation of the liquid (L) only in the direction from said membrane (220) to said hydraulic turbine (270).

6. Stamping press (100) according to one of claims 1 to 5, characterized in that said energy recovery device (200) comprises a rigid belt (210) resting fixedly against said upper receiving face (11 IA) of the base (111), said belt (210) defining a recess (211) extending from its lower face and housing the main part (221) of said membrane (220), the upper part of said belt (210) extending above said recess (211) having a plurality of holes (212) crossed by hollow protrusions (222) of said membrane (220) fluidly connected to its main part (221), said protrusions (222) projecting above said belt (210) forming bubbles (223) filled with liquid (L) intended to be compressed by said lower die (140) when lowering said upper die (130) against the latter.

7. Stamping press (100) according to claim 6, characterized in that said energy recovery device (200) comprises elastic return means (230) capable of holding said lower die (140), in the absence of compression forces exerted against it by said upper die (130), away from said belt (210) so that its lower face is flush with the top of said bubbles (223) without exerting any compression force on the latter.

8. Stamping press (100) according to one of claims 6 or 7, characterized in that said protrusions (222) and said holes (212) are arranged regularly in rows and columns so as to form a grid.

9. Subassembly (1) comprising a stamping press (100) according to one of claims 1 to 8 and a belt conveyor (300), said turbine (270) comprising a rotor whose shaft is coupled to one of the turning rollers of said conveyor (300) so as to ensure its drive.

10. Subassembly (1) according to claim 9, characterized in that the coupling between the shaft of the rotor of said turbine (270) and that of said turning roller of the belt conveyor (300) is ensured by means of a mechanical gear reducer (290) so as to allow the forward speed of this conveyor (300) to be adjusted.

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