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EP-4430313-B1 - DEVICE FOR VIBRATION-DAMPED FASTENING OF A WORKPIECE

EP4430313B1EP 4430313 B1EP4430313 B1EP 4430313B1EP-4430313-B1

Inventors

  • LANDKAMMER, STEFAN
  • Seefried, Christoph
  • EHMANN, Sergius

Dates

Publication Date
20260513
Application Date
20221228

Claims (12)

  1. Device for detachable fastening of a workpiece (1) comprising a screw (3) or a threaded bar and the workpiece (1) with a through hole (31) for feeding through the screw (3) or the threaded bar, wherein the device comprises at least two elastically deformable punched discs (6, 7), each of which has a through hole (32, 33) for feeding through the screw (3) or the threaded bar, wherein the workpiece (1) has a first contact surface (10) for contacting a first punched disc (6) and a second contact surface (11) for contacting a second punched disc (7) on both sides of the through hole (31), wherein the workpiece (1) is embodied to receive the first punched disc (6) resting on the first contact surface (10) and the second punched disc (7) resting on the second contact surface (11) in the region of its through hole (31) in conventional assembly positions predetermined in each case such that the through holes (31, 32, 33) of the workpiece (1) and the first punched disc (6) and the second punched disc (7) are arranged so as to overlap at least partially so that the screw (3) or the threaded bar can be passed through the through hole (31) of the workpiece and through the through hole (32) of the first punched disc (6) and through the through hole (33) of the second punched disc (7), wherein the first punched disc (6) comprises a tube-shaped first sleeve (13) for feeding the screw (3) or the threaded bar through the tube-shaped first sleeve (13), which delimits a deformation of the first punched disc (6) in the radial direction with respect to the axis of the through hole (32) of the first punched disc (6) and wherein the second punched disc (7) comprises a tube-shaped second sleeve (18) for feeding the screw (3) or the threaded bar through the tube-shaped second sleeve, which delimits a deformation of the second punched disc (7) in the radial direction with respect to the axis of the through hole (33) of the second punched disc (7), wherein the first sleeve (13) projects beyond a first contact surface (8) of the first punched disc (6) for contacting the first contact surface (10) of the workpiece so that the first sleeve (13) projects into the through hole (31) in the workpiece (1) in the predetermined, conventional assembly position of the first punched disc (6) and wherein the second sleeve (18) projects beyond a second contact surface (9) of the second punched disc (7) for contacting the second contact surface (11) of the workpiece (1) so that the second sleeve (18) projects into the through hole (31) in the workpiece (1) in a predetermined, conventional assembly position of the second punched disc (7), wherein the workpiece (1) has a predetermined free clearance in the radial direction with respect to the axis of the through hole (32) through the first punched disc (6) in the predetermined, conventional assembly position and in a relaxed state of the first punched disc (6) around the first punched disc (6) so that the first punched disc (6) can deform elastically in a radial direction to at least a predetermined degree, and wherein the workpiece (1) has a predetermined free clearance in the radial direction with respect to the axis of the through hole (33) through the second punched disc (7) in the predetermined, conventional assembly position and in a relaxed state of the second punched disc (7) around the second punched disc (7) so that the second punched disc (7) can deform elastically in the radial direction to at least a predetermined degree, characterised in that a wall thickness of the workpiece (1) between the first contact surface (10) and the second contact surface (11) is matched to the first and the second sleeves (13, 18) projecting into the through hole of the workpiece so that a predetermined distance (27) of greater than zero is embodied in a predetermined, conventional assembly position of the first and the second punched disc (6, 7) and in the relaxed state of the first and the second punched disc (6, 7) between the two end faces (25, 26) of the first and second sleeve (13, 18) arranged opposite to one another in the through hole (31) of the workpiece (1).
  2. Device according to claim 1, characterised in that the workpiece (1) has a first recess for receiving the first punched disc (6), wherein a first base area of the first recess forms the first contact surface (10) for contacting the first punched disc (6) and wherein the first recess is embodied such that side surfaces (23) of the first recess have a predetermined distance (28) of greater than zero with respect to the first punched disc (6) in the predetermined, conventional assembly position and in the relaxed state of the first punched disc (6) and/or that the workpiece has a second recess for receiving the second punched disc (7), wherein a second base area of the second recess forms the second contact surface (11) for contacting the second punched disc (7) and wherein the second recess is embodied such that side surfaces (24) of the second recess have a predetermined distance (29) of greater than zero with respect to the second punched disc (7) in the predetermined, conventional assembly position and in the relaxed state of the second punched disc (7).
  3. Device according to one of claims 1 or 2, characterised in that the distance (27) of the front faces (25, 26), arranged opposite to one another in the through hole (31) of the workpiece (1), of the first and second sleeve (13, 18) and the free clearances in the radial direction with respect to the axes of the through holes (32, 33) through the first and second punched discs (6, 7) are predetermined as a mutual function of and as a further function of the stabilities of the first and second punched disc (6, 7) and of a predetermined pretensioning force applied by means of the screw (3) or the threaded bar.
  4. Device according to one of claims 1 to 3, characterised in that the first punched disc (6) has a protuberance (15), which projects into the through hole (31) of the workpiece (1) in a predetermined, conventional assembly position of the first punched disc (6) and/or that the second punched disc (7) has a protuberance (20) which projects into the through hole (31) of the workpiece (1) in a predetermined, conventional assembly position of the second punched disc (7).
  5. Device according to one of claims 1 to 4, characterised in that the first punched disc (6) comprises a first lining disc (14) for contacting a screw head (4) of the screw (3) or a threaded carrier for screwing to the threaded bar, which is arranged in a predetermined, conventional assembly position of the first punched disc (6) on a side of the first punched disc (6) opposite the first contact surface (8) and which is fixedly embodied and effects a uniform force transmission of a pretensioning force applied by the screw head (4) or the threaded carrier into the first punched disc (6) and/or that the second punched disc (7) comprises a second lining disc (19) for contacting a screw head of the screw or a threaded carrier (5) for screwing to the screw or threaded bar, which, in a predetermined, conventional assembly position of the second punched disc (7), is arranged on a side of the second punched disc (7) opposite to the second contact surface (9) and which is fixedly embodied and effects a uniform force transmission of a pretensioning force applied by the screw head or the threaded carrier (5) into the second punched disc (7).
  6. Device according to claim 5, characterised in that the first lining disc (14) and the first sleeve (13) are fixedly connected to one another and/or the second lining disc (19) and the second sleeve (18) are fixedly connected to one another.
  7. Device according to claim 2, characterised in that the distance (28) from the side surfaces (23) of the first recess in respect of the first punched disc (6) is predetermined in the predetermined, conventional assembly position and in the relaxed state of the first punched disc (6) as a function of the stability of the first punched disc (6) such that with a predetermined pretensioning force applied by means of the screw (3) or the threaded bar, the first punched disc (6) deformed elastically as a result rests against the side surface (23) of the first recess and/or the distance (29) from the side surfaces (24) of the second recess in respect of the second punched disc (7) is predetermined in the predetermined, conventional assembly position and in the relaxed state of the second punched disc (7) as a function of the stability of the second punched disc (7) such that with a predetermined pretensioning force applied by means of the screw (3) or the threaded bar, the second punched disc (7) which is elastically deformed as a result rests against the side surfaces (24) of the second recess.
  8. Device according to one of claims 1 to 7, characterised in that the workpiece (1) is produced from plastic using a generative production method.
  9. Device according to claim 8, characterised in that the workpiece (1) is produced at least partially in layers, wherein the layers in the region of the first and second contact surface (10, 11) have a directional component in the axial direction with respect to the through hole (31) so that a force transmission is distributed onto different layers by the punched discs (6, 7) which are pretensioned mutually against the workpiece.
  10. Device according to one of claims 1 to 9, characterised in that the workpiece (1) is a cover part for a vehicle.
  11. Vehicle with at least one device according to one of claims 1 to 10.
  12. Vehicle according to claim 11, characterised in that the at least one device is assembled on a point with high cyclical operating loads.

Description

The invention relates to a device for the detachable fastening of a workpiece comprising a screw or a threaded rod and the workpiece to be fastened with a through-hole for the passage of the screw or the threaded rod. Workpieces in undamped areas of vehicles, such as body panels on the chassis of rail vehicles, are exposed to undamped shocks, vibrations, or oscillations with a high number of cycles. Therefore, workpieces made of plastics with low fatigue strength, such as those commonly used in additively manufactured parts, have not been used in these areas. Conventional screw connections for fastening such workpieces, which inherently introduce local stress peaks into the plastic component, further contribute to the inability to withstand these loads, as even low cyclic loads can lead to material damage, cracking, and ultimately, fracture. Printed matter DE 10 2011 079 617 A1 discloses a generic device for the detachable fastening of a workpiece according to the features of the preamble of independent claim 1. The invention is based on the objective of increasing the availability of workpieces in undamped areas of vehicles. The problem is solved by the subject matter of independent patent claim 1. Further developments and embodiments of the The invention is reflected in the features of the dependent patent claims. A device according to the invention for the detachable fastening of a workpiece comprises a screw or a threaded rod, the workpiece to be fastened, and at least two elastically deformable perforated discs, each having a through-hole for the passage of the screw or threaded rod. The workpiece to be fastened is hereinafter referred to simply as the workpiece. It has a through-hole for the passage of the screw or threaded rod, as well as a first bearing surface for the bearing of a first perforated disc and a second bearing surface for the bearing of a second perforated disc on both sides of the through-hole. The workpiece is designed to accommodate the first perforated disc against the first bearing surface and the second perforated disc against the second bearing surface in the region of their respective through-holes in such a way that the through-holes of the workpiece and of the first and second perforated discs are at least partially overlapping, so that the screw or threaded rod can pass through the through-hole of the workpiece, through the through-hole of the first perforated disc, and through the through-hole of the second perforated disc. Furthermore, the workpiece is designed such that it has a predetermined free space around the first perforated disc in the radial direction to the axis of the through-hole through the first perforated disc in the predetermined, intended mounting position of the first perforated disc and in a relaxed state of the first perforated disc, so that the first perforated disc can deform elastically in the radial direction to at least a predetermined extent. Likewise, the workpiece has a predetermined free space around the second perforated disc in the radial direction to the axis of the through-hole through the second perforated disc in the predetermined, intended mounting position and in a relaxed state of the second perforated disc, so that the second perforated disc can deform elastically in the radial direction to at least a predetermined extent. The workpiece may be a fairing part for a vehicle, in particular for a rail vehicle, especially for a chassis or bogie of the rail vehicle. A vehicle according to the invention, in particular a rail vehicle, comprises at least one device according to the invention for the detachable fastening of a workpiece. The workpiece can be mounted in an unsprung, undamped area of the vehicle or at a location on the vehicle where it is exposed to high, cyclic operating loads, in particular vibrations or oscillations, especially with a high number of cycles, and/or shocks. For example, it is arranged on a chassis or bogie of the vehicle and detachably fastened. For example, the workpiece is a panel or a cover part, in particular for undamped areas of the vehicle, such as a cover for a chassis or bogie of the vehicle. The workpiece is detachably fastened to a component, particularly a vehicle, such as a chassis frame, using a screw or threaded rod, which can also be called a threaded bolt. It is screwed to the component. To create this screw connection, the component itself can have a bore with a complementary internal thread to the external thread of the screw or threaded rod, or it can have a through hole, and the fastening is achieved using an additional threaded support, such as a nut. The screw can thus be designed as a through bolt with a matching threaded support, or as a stud bolt or threaded stud, in which case the component has an internal thread complementary to the external thread of the screw and therefore itself acts as the threaded support. A threaded rod is used analogously. An additional threaded insert is use