DEVICE FOR VIBRATION-DAMPED MOUNTING OF A WORKPIECE

Description

[0001] 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.

[0002] 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 failure to withstand these loads, as even low cyclic loads can lead to material damage, cracking, and ultimately, breakage.

[0003] Publication 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.

[0004] The invention is based on the objective of increasing the availability of workpieces in undamped areas of vehicles.

[0005] The problem is solved by the subject matter of independent patent claim 1. Further developments and embodiments of the invention are found in the features of the dependent patent claims.

[0006] 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 of which has a through-hole for the passage of the screw or the 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 the 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 contact surface and the second perforated disc against the second contact surface in the area of ​​its through-hole in such a way as to accommodate the first perforated disc against the second contact surface in the area of ​​its through-hole in predetermined, intended mounting positions, such that the through-holes of the workpiece and of the first perforated disc and of the second perforated disc are arranged to be at least partially overlapping, so that the screw or threaded rod can be passed through the through-hole of the workpiece and 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.

[0007] 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.

[0008] 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.

[0009] 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 insert, such as a nut. The screw can thus be designed as a through bolt with a matching threaded insert, 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 a threaded insert. Similarly, with a threaded rod, an additional threaded insert is used instead of the screw head.The screw connection applies an axial preload to the workpiece, acting towards the through-hole of the workpiece, with the spacers placed between the screw head or the threaded carrier and the further threaded carrier.

[0010] This axial preload causes the perforated discs to deform elastically. Each disc incorporates an elastic material, particularly an elastomer such as rubber. This ensures that the perforated discs make full contact with the respective contact surfaces and that the force is transferred evenly into the workpiece. Simultaneously, the elastic material serves to dampen vibrations and / or provide spring action.

[0011] The workpiece itself is made of a different material. It comprises, in particular, a plastic, for example a polymer, which can also exhibit low fatigue strength. The fastening according to the invention enables the use of such materials.

[0012] According to further training, the workpiece is manufactured from a plastic using a generative, specifically additive, layer-by-layer manufacturing process. Amorphous materials with good thermoplastic processability are suitable for additive manufacturing. The workpiece can be manufactured layer by layer, at least partially, with a radial component or even axially to the through-hole, so that the force applied by the perforated discs, which are pre-tensioned against the workpiece by means of the screw or threaded rod, is distributed across different layers.

[0013] During assembly of the device, the workpiece is aligned with the component to which it is to be attached, particularly at a location subject to high, cyclic operating loads, for example, on the frame of a vehicle chassis. The first and second perforated discs each have a contact surface for resting against the respective contact surfaces of the workpiece. They are aligned with and positioned against the workpiece such that the first perforated disc rests with its first contact surface against the first contact surface of the workpiece, and the second perforated disc rests with its second contact surface against the second contact surface of the workpiece.In the respective specified, intended mounting positions, the through-holes of the workpiece and the first and second perforated discs are at least partially overlapping, and the screw or threaded rod passes through the through-hole of the workpiece and through the through-holes of the first and second perforated discs. In a relaxed state, the first perforated disc has a predetermined free space radially around it, relative to the axis of the through-hole, allowing it to deform elastically in the radial direction to a predetermined extent.Similarly, in a relaxed state of the second perforated disk, a predetermined free space is provided in the radial direction to the axis of the through-bore through the second perforated disk around the second perforated disk, so that the second perforated disk can deform elastically in the radial direction to at least a predetermined extent.

[0014] The workpiece to be fastened has, for example, a wall through which the through-hole passes. The wall thickness is appropriately chosen. The first contact surface is formed on one side of the wall, and the second contact surface is formed on the opposite side of the wall. Thus, the first and second contact surfaces are located on different sides of the wall and oriented in opposite directions, so that the first perforated disc rests against the first side of the wall and the second perforated disc rests against the second side of the wall.

[0015] The contact surfaces are designed to be complementary to the bearing surfaces, for example, flat. The first perforated disc contacts the first side of the workpiece across its entire surface, particularly its full surface. Similarly, the second perforated disc contacts the second side of the workpiece across its entire surface, particularly its full surface. The contact and bearing surfaces can also be chamfered, for example, conical or frustoconical, or even curved, for example, spherical segment-shaped. The first perforated disc can be pre-tensioned against the first side of the workpiece by means of a screw connection, using the screw or threaded rod. Simultaneously, during assembly, the second perforated disc is pre-tensioned against the second side of the workpiece by means of the screw connection or threaded rod.

[0016] The axes of the through-holes through the workpiece and through the first and second perforated discs can coincide. The diameter of the through-hole through the workpiece can be larger than the diameters of the through-holes through the perforated discs. If the axes coincide, the through-holes of the perforated discs will then overlap the through-hole through the workpiece. With identical diameters, the first and second perforated discs can be aligned so that their through-holes are aligned. The through-hole through the workpiece for the screw or threaded rod has a diameter that is dimensioned relative to the screw or threaded rod such that the workpiece is free from contact with the screw or threaded rod, both in the stress-free state of the perforated discs and in the preloaded state during operation of the device, and thus under vibration.

[0017] For assembly, the workpiece can be attached to the component in the following sequence, for example. A screw head or a threaded insert, such as a nut, clamps the first perforated washer against the workpiece. The second perforated washer rests against the other side of the workpiece. This washer is pre-tensioned against the workpiece by means of the component, which has an internal thread into which the external thread of the screw engages. Alternatively, the component is pre-tensioned between the second perforated washer and another threaded insert, such as a nut, against the second perforated washer and against the workpiece. In this case, the component also has a through-hole.

[0018] According to a further development of the invention, the workpiece has a first recess for receiving the first perforated disc, wherein a first base surface of the first recess forms the first contact surface for the first perforated disc, and wherein the first recess is designed such that the side surfaces of the first recess have a predetermined distance greater than zero to the first perforated disc in the predetermined, intended mounting position and in the relaxed state of the first perforated disc. Similarly, the workpiece can have a second recess for receiving the second perforated disc, wherein a second base surface of the second recess forms the second contact surface for the second perforated disc, and wherein the second recess is designed such that the side surfaces of the second recess have a predetermined distance greater than zero to the second perforated disc in the predetermined, intended mounting position and in the relaxed state of the second perforated disc.

[0019] The first and / or second recess can be designed as a blind hole. If the first and / or second perforated disc has a circular cross-section, the first recess designed as a blind hole has an inner diameter that is larger by a predetermined amount than the outer diameter of the first perforated disc, which has a circular cross-section, in its relaxed state. Similarly, the second recess designed as a blind hole can have an inner diameter that is larger by a predetermined amount than the outer diameter of the second perforated disc, which has a circular cross-section, in its relaxed state.

[0020] In the specified mounting position of the perforated discs, the axes of the first and / or second recesses coincide with the axes of the perforated discs. The axes of the respective through holes are then also identical. The circular bases of the blind recesses form the contact surfaces for the perforated discs; thus, the first base of the first recess forms the first contact surface for the first perforated disc, and / or the second base of the second recess forms the second contact surface for the second perforated disc. The lateral surfaces of the blind holes can correspondingly form the side surfaces of the recesses. The recesses are therefore bounded by their respective contact surfaces and side surfaces.

[0021] In the relaxed state of the first perforated disc, i.e., a stress-free and undeformed state, the first recess in the workpiece for the first perforated disc is dimensioned such that the first perforated disc can expand elastically by a predetermined amount from the relaxed state into a deformed state caused by an axial preload. The same applies to the second perforated disc: the second recess in the workpiece for the relaxed second perforated disc is dimensioned such that it can expand elastically by a predetermined amount from the relaxed state into a deformed state caused by an axial preload. The axial preload can be applied to the first and / or second perforated disc by means of the screw or threaded rod.

[0022] As above, it could also be said here that the first recess is complementary to the first perforated disc and / or that the second recess is complementary to the second perforated disc.

[0023] According to one embodiment, the first and / or second recess is deep enough to completely accommodate the first and / or second perforated disc. When in contact with the respective contact surface, the first and / or second perforated disc is recessed within its respective recess. For example, the side of the first and / or second perforated disc facing away from the respective contact surface can be flush with the first workpiece, or the side surfaces of the respective recess can extend beyond the first and / or second perforated disc, so that, for example, a screw head or threaded insert bearing against the first perforated disc is at least partially accommodated within the first recess.

[0024] Alternatively, the first and / or second recess can be designed in such a way that the first and / or second perforated disc projects at least partially beyond the respective first and / or second recess. For example, the thickness of the first and / or second perforated disc between its bearing surface and the opposite side is greater than the depth of the first and / or second recess; in particular, at the edge of such a first and / or second perforated disc, it has a greater thickness than the height of the respective side surfaces of the recess.

[0025] The specified free space in the radial direction to the axis of the through-hole through the first and / or second perforated disc in the specified, intended mounting position and in a relaxed state of the first and / or second perforated disc around the first and / or second perforated disc can extend over the entire thickness of the elastic part of the first and / or second perforated disc from the first and / or second bearing surface to its side opposite the corresponding first and / or second bearing surface, for example up to a first and / or second washer, of the first and / or second perforated disc, so that the first and / or second perforated disc can expand radially over this entire thickness.

[0026] According to a further embodiment of the invention, the workpiece and the first perforated disc are designed such that, in the predetermined, intended mounting position and in a relaxed state of the first perforated disc, the distance between the first perforated disc and the workpiece in the radial direction to the axis of the through-hole through the first perforated disc is zero, or the first perforated disc is radially pre-tensioned by the workpiece in the predetermined, intended mounting position and in a state of the first perforated disc not pre-tensioned by the screw or threaded rod. The first perforated disc is then radially clamped in the workpiece. The clamping occurs only section by section. Thus, only a section of the first perforated disc, in particular the elastically deformable part of the first perforated disc, is radially clamped by the workpiece.This section is particularly small compared to the area of ​​the first perforated disk, especially the elastically deformable part of the first perforated disk which can expand freely radially, so that the first perforated disk can still deform elastically in the radial direction to at least a predetermined extent.Similarly, the workpiece and the second perforated disc can be designed such that, in the intended mounting position and in a relaxed state, the distance between the second perforated disc and the workpiece is zero in the radial direction relative to the axis of the through-hole through the second perforated disc. Alternatively, in the intended mounting position and in a state where the second perforated disc is not pre-tensioned by the screw or threaded rod, the second perforated disc can be radially pre-tensioned by the workpiece in the radial direction relative to the axis of the through-hole through the second perforated disc, and thus clamped radially within the workpiece in sections. The workpiece and the first and / or second perforated disc therefore exhibit a transition or interference fit in the area for receiving at least the elastically deformable part of the first and / or second perforated disc.In particular, the distance between the side surfaces of the first and / or second recess and at least the elastically deformable part of the first and / or second perforated disc is equal to or less than zero (clamping) in the specified, intended mounting position and in a state where the first and / or second perforated disc is not pre-tensioned by the screw or threaded rod. Furthermore, there is free space in the radial direction around the first and / or second perforated disc, allowing the first and / or second perforated disc to deform elastically in the radial direction to at least a specified extent.The predetermined free space in the radial direction to the axis of the through-hole through the first and / or second perforated disc in the predetermined, intended mounting position and in the relaxed state of the first and / or second perforated disc does not extend over the entire thickness and / or circumference of at least the elastic part of the first and / or second perforated disc between its first and / or second bearing surface and the side of the perforated disc opposite the corresponding first or second bearing surface. This can be achieved, for example, by at least one or, in particular, several lugs projecting into the recess or by differently shaped protrusions in the side surfaces of the first and / or second recess. An annular elevation in the side surfaces acting as a protrusion is also included here. Additionally or alternatively, radially acting protrusions of the first and / or second perforated disc are also conceivable.

[0027] This clamping mechanism also makes it more difficult or prevents the first and / or second perforated disc and the workpiece from twisting relative to each other.

[0028] The device according to the invention comprises several individual parts or components, including the workpiece, the perforated discs and the screw or threaded rod, so that it could also be referred to as a construction or assembly set or kit for a detachable, vibration-damping connection of the workpiece to the component or a detachable, vibration-damped connection of the workpiece to the component.

[0029] The invention simplifies the connection of workpieces, particularly those with low fatigue strength, in undamped areas of vehicles, while simultaneously increasing their service life. This ensures the usability, functionality, and suitability of additively manufactured workpieces, especially in undamped areas of vehicles, and thus improves the overall availability of workpieces. Operating loads are distributed to reduce stress input from screw connections in additively manufactured workpieces. Further advantages of the invention include: The perforated discs, acting as damping elements, conform to the contour of the workpiece, thereby generating a uniformly distributed holding force in all spatial directions and a holding force distributed over a larger area, resulting in lower surface loads; a uniformly distributed force input ensures lower local stress peaks, leading to a longer service life; vibration damping is enabled in all three spatial directions; in additive workpieces, the force application is distributed across different layers, thus reducing the risk of critical loads at layer interfaces with low strength.

[0030] Furthermore, the disadvantages of conventional screw connections, which introduce local stresses into the component that are further increased by operating loads, are overcome. Screw connections of plastic parts were therefore often the strength-limiting or service life-determining element in components. Screw points were thus generally the critical, service life-determining areas for additively manufactured components because locally concentrated stresses are introduced into the component. Areas exposed to shocks and vibrations, such as on the bogie of a rail vehicle, were particularly critical for the use of additively manufactured components. With this invention, the use of many more different workpiece materials is now possible. Even cyclic operating loads, vibrations, and shocks can be accommodated without local material damage by avoiding stress peaks.

[0031] The features and combinations of features described below serve to further improve the aspects mentioned.

[0032] According to the invention, the first perforated disc has a first sleeve in a through-hole through an elastically deformable part of the first perforated disc for the passage of the screw or threaded rod, which limits deformation of the elastically deformable part of the first perforated disc in the radial direction towards the axis of the through-hole of the first perforated disc. Similarly, the second perforated disc also has a second sleeve in a through-hole through an elastically deformable part of the second perforated disc for the passage of the screw or threaded rod, which limits deformation of the elastically deformable part of the second perforated disc in the radial direction towards the axis of the through-hole of the second perforated disc.The first and / or second sleeve, in contrast to the elastic material of the elastically deformable part of the first and / or second perforated disc, is rigid and is primarily made of a metal or metal alloy. It can be tubular or hollow-cylindrical to accommodate the screw or threaded rod. Each sleeve provides a passage for the screw or threaded rod, thus defining the through-hole in the perforated disc. The screw or threaded rod is then guided through the sleeve in the perforated disc. The first and / or second sleeve can be bonded to the elastically deformable part of the first and / or second perforated disc, forming a so-called rubber-metal element.The relatively stiff first and / or second sleeve counteracts and limits the expansion under axial preload of the elastically deformable part of the first and / or second perforated disc in the radial direction, i.e. into the respective through-hole.

[0033] Furthermore, it is provided that the first sleeve projects beyond the first bearing surface of the first perforated disc by a predetermined amount greater than zero, so that, in the predetermined, intended mounting position of the first perforated disc, the first sleeve projects into the through-hole in the workpiece by a predetermined amount greater than zero. Similarly, the second sleeve projects beyond the second bearing surface of the second perforated disc by a predetermined amount greater than zero, so that, in the predetermined, intended mounting position of the second perforated disc, the second sleeve projects into the through-hole in the workpiece by a predetermined amount greater than zero.

[0034] To accommodate the first and / or second sleeve, the diameter of the workpiece's through-hole must be at least equal to or larger than the outer diameter of the first and / or sleeve. As explained above, the inner diameter of the first and / or second sleeve, and thus the diameter of the through-hole of the first and / or second perforated disc, must be at least suitable for the passage of the screw or threaded rod.

[0035] The first perforated disc has a first sleeve, and the second perforated disc has a second sleeve. In the predetermined, intended mounting position of the first and second perforated discs, the first sleeve and the second sleeve project into the through-hole of the workpiece.

[0036] In a further development, at least the first perforated disc has a first protrusion of the elastically deformable part, in particular a hollow cylindrical protrusion, which protrudes over the first bearing surface of the first perforated disc to a predetermined extent greater than zero for the first perforated disc to abut the first bearing surface of the workpiece, so that the first protrusion projects into the through-hole in the workpiece to a predetermined extent greater than zero in the predetermined, intended mounting position of the first perforated disc.The second perforated disc can also have such a second protrusion, in particular a hollow cylindrical one, of the elastically deformable part of the second perforated disc. This second protrusion projects beyond the second bearing surface of the second perforated disc by a predetermined amount greater than zero, so that, in the predetermined, intended mounting position of the second perforated disc, the second protrusion projects into the through-hole in the workpiece by a predetermined amount greater than zero. The first and / or second protrusion is, in particular, made of the same elastically deformable material as the respective elastically deformable part of the first and / or second perforated disc and is connected to it without joints. In particular, the elastically deformable part of the first and / or second perforated disc and the respective first and / or second protrusion are formed monolithically.The first and / or second protrusion has a through-hole for receiving the screw or threaded rod, which in particular has the same inner diameter as the corresponding elastically deformable part of the first and / or second perforated disc. Likewise, the first and / or second sleeve can be enclosed by the respective first and / or second protrusion. Thus, the first and / or second protrusion limits the first and / or second perforated disc inwards towards the axis of the through-hole, and the inner diameter of the first and / or second protrusion is suitable for the passage of the screw or threaded rod. Alternatively, the corresponding first and / or second sleeve is enclosed within the first and / or second protrusion, which in turn limits the respective through-hole of the first and / or second perforated disc for receiving the screw or threaded rod inwards towards the axis of the through-hole.

[0037] As already explained above, the through-hole of the workpiece can be larger than the through-hole of the perforated discs, especially to accommodate a sleeve and / or protrusion.

[0038] The wall thickness of the workpiece in the area of ​​the through-hole between the first and second contact surfaces is such that, in the predetermined, intended mounting position of the first and second perforated discs and in the relaxed state of the first and second perforated discs, a predetermined distance greater than zero is formed in the axial direction between the two opposing end faces of the first and second perforated discs in the area of ​​the through-hole. If both the first and second perforated discs each have a sleeve and / or a protrusion, their end faces located in the through-hole of the workpiece face each other and form the predetermined distance greater than zero in the axial direction.It could also be described as an axial gap in the through-hole of the workpiece between the end faces of the first and second perforated disc.

[0039] In a further development, the first and second perforated discs are designed such that the distance of a predetermined dimension greater than zero between the opposing end faces of the first and second perforated discs in the area of ​​the through-hole can be closed by applying a predetermined preload using the screw or threaded rod, resulting in elastic deformation of the first and second perforated discs. This occurs in the predetermined, intended mounting position of the first and second perforated discs and in their relaxed state. The distance or gap between the perforated discs can be adjusted and thus predetermined by selecting the design, in particular the dimensions, and the materials and thus their physical properties.

[0040] According to a further development of the device, the axial distance between the two opposing end faces of the first and second perforated disc in the area of ​​the through-hole through the workpiece and the free space around the first and / or second perforated disc in the radial direction to the axis of the through-hole through the workpiece in the specified, intended mounting position of the first and / or second perforated disc and in a relaxed state of the first and / or second perforated disc mutually dependent and further dependent on the strength, for example a Shore hardness or comparable strength characteristics, in particular at least of the elastically deformable part, the first and / or second perforated disc and an axial preload applied by means of the screw or threaded rod The adjustment is specifically designed so that a predetermined elastic deformation of the first and / or second perforated disc in the radial and / or axial direction is not exceeded. The axial preload applied by means of the screw or threaded rod is also predetermined. It is specified in such a way as to ensure secure assembly even during operation.

[0041] For example, the distance between opposing end faces of the first and second sleeves arranged in the through-hole of the workpiece and the free spaces in the radial direction around the first and second perforated disc to the axes of the through-holes through the first and second perforated discs are mutually dependent and further dependent on the strengths of the first and second perforated discs and on the predetermined preload applied by means of the screw or threaded rod.

[0042] The distance between the side surfaces of the first recess and the first perforated disc in the specified, intended mounting position and in the relaxed state of the first perforated disc is further defined, depending on the strength of the first perforated disc, such that when a specified preload force is applied by means of the screw or threaded rod, the elastically deformed first perforated disc rests against the side surfaces of the first recess. Similarly, the distance between the side surfaces of the second recess and the second perforated disc in the specified, intended mounting position and in the relaxed state of the second perforated disc can be defined, depending on the strength of the second perforated disc, such that when a specified preload force is applied by means of the screw or threaded rod, the elastically deformed second perforated disc rests against the side surfaces of the second recess.As already explained above, this can be further dependent on the distance between the opposing end faces of the first and second sleeves arranged in the through-hole of the workpiece, and if necessary further dependent on the strengths, for example Shore hardnesses, of the first and second perforated disc, or at least on the elastically deformable parts of the first and second perforated disc, and on the predetermined preload force applied axially by means of the screw or threaded rod.

[0043] Further advantages of the invention, particularly when at least one sleeve is present, include an adjustable ratio between the preload force of the screw connection and the clamping force of the perforated washers via the distance between the opposing end faces of the first and second perforated washers arranged in the through-hole of the workpiece (clamping gap). The preload force of the screw connection by means of the screw or threaded rod, and thus the clamping force, can be increased up to the load limit of the screw or threaded rod. There is no longer a problem due to settling loss of the workpiece's plastic. Additional screw locking devices such as wedge washers, spring washers, or similar can be used regardless of the settling behavior of the workpiece's additive plastic.

[0044] The following further developments of the device according to the invention are proposed for further improvement.

[0045] According to a further development, at least the first perforated disc includes a fixed first washer for bearing against the screw head or for bearing against a threaded support, such as a nut, for fastening to the threaded rod. This first washer is positioned in the predetermined, intended mounting position of the first perforated disc on a side of the first perforated disc opposite the first bearing surface. The first washer has high strength and is therefore rigid compared to the elastic part of the first perforated disc. It comprises, in particular, a metal or a metal alloy and counteracts and limits the deformation of the elastically deformable part of the first perforated disc in the axial direction towards the first washer.Furthermore, the first washer ensures a uniform application and distribution of the preload force applied by the screw head or threaded insert into the first perforated washer. It thus serves to improve and distribute the force across the surface of the first perforated washer. The first washer is firmly, and in particular by a material bond, connected to the elastic part of the first perforated washer, for example, by adhesive bonding.Similarly, the second perforated disc can comprise a fixed second washer, in particular made of a metal or a metal alloy, which is connected to the elastic part of the second perforated disc in a material-bonded manner, for bearing a screw head of the screw or for bearing a threaded support, for example a nut, for screwing with the threaded rod, which second washer is arranged in a predetermined, intended mounting position of the second perforated disc on a side of the second perforated disc opposite the second bearing surface of the second perforated disc.

[0046] In a further developed form, the first and / or second washer extends over the entire surface of the corresponding first and / or second perforated washer opposite the corresponding first and / or second bearing surface.

[0047] In this further developed form, the first washer and the first sleeve are firmly, and in particular materially, joined together, especially without joints. The first sleeve and the first washer can also be formed monolithically. For example, the base body of the first washer and the first sleeve could be manufactured from a single casting. The first washer could also be described as the radial collar of the first sleeve. The entire assembly of the first washer and the first sleeve could be described as a hollow cylindrical plug, axle sleeve, or bushing. The second washer and the second sleeve can be formed in the same way.

[0048] Furthermore, it can be provided that at least the first bearing surface of the first perforated disc is also rigidly formed. Similarly, the second bearing surface of the second perforated disc can also be rigidly formed. For this purpose, the first and / or second perforated disc can again have a rigid first and / or second washer, in particular one comprising or made of a metal or metal alloy, which is rigidly, in particular by a material bond, connected to the corresponding elastically deformable part of the first and / or second perforated disc, for example, by adhesive bonding. The first and / or second washer then each forms the corresponding first and / or second bearing surface of the first and / or second perforated disc for contact with the corresponding first and / or second contact surface of the workpiece.The first and / or second washer, like the first and / or second washer, ensures a uniform force distribution into the respective perforated disc. As explained above, the first and / or second contact surface formed by the first and / or second washer is designed to complement the corresponding first and / or second contact surface of the workpiece, ensuring a flat contact between the first and / or second perforated disc and the workpiece.

[0049] The first washer can also have a hollow cylindrical collar that, in the specified, intended mounting position of the first perforated washer, projects at least partially into the through-hole in the workpiece. The first collar can thus serve as the first outer sleeve for the first protrusion and at least partially enclose it. It is designed to engage with the through-hole of the workpiece and form a fit with it. Its outer diameter would then be only minimally smaller than or equal to the outer diameter of the through-hole of the workpiece in the area of ​​the first collar. The first collar can also be materially bonded to the first protrusion of the elastically deformable part of the first perforated washer, for example, by adhesive bonding. In particular, the first collar is materially bonded, especially without joints, to the first washer, especially if it is formed from it.Similarly, the second washer can also have a hollow cylindrical second collar that, in the specified, intended mounting position of the second perforated washer, projects at least partially into the through-hole in the workpiece. The other features described for the first perforated washer are also applicable to the second perforated washer by analogy.

[0050] The invention allows for numerous embodiments. It is explained in more detail with reference to the following figure, which shows one embodiment example.

[0051] The figure schematically shows a partial section of a device according to the invention for the detachable, vibration-damping connection of a workpiece 1 to a component 2. Component 2 is, in this case, the chassis of a rail vehicle. The workpiece 1 is a cover or other cladding part for the chassis. It is detachably mounted and clamped to component 2 by means of a screw connection, comprising a screw 3 with a screw head 4 and a cage nut as a threaded carrier 5. The cage nut, as the threaded carrier 5, forms the counterpart to the screw head 4, which has an internal thread, and is designed to be complementary to the screw 3.

[0052] Both workpiece 1 and component 2 have a through-hole 31 for the passage of screw 3. Furthermore, the device has two perforated discs 6 and 7, which, in the illustrated assembled state and in the specified mounting position, bear their contact surfaces 8 and 9 against contact surfaces 10 and 11 of workpiece 1 in the area of ​​the through-hole 31 through workpiece 1.

[0053] The first perforated disc 6 comprises a vibration-damping, elastically deformable part 12, a first sleeve 13 and a first washer 14. The elastically deformable part 12 is made of an elastomer, for example rubber.

[0054] The first washer 14 can be rigidly connected to the elastically deformable part 12. It is located on the side of the first perforated disc 6 opposite the first bearing surface 10 of the first perforated disc 6, and thus, in the assembly position shown, on the side of the first perforated disc 6 facing away from the first bearing surface 8 of the workpiece 1 and the through-hole 31 through the workpiece 1. The screw head 4 rests against the first washer 14 of the first perforated disc 6 with the interposition of locking washers 16. The forces acting on the first perforated disc 6 by the screw head 4 are distributed evenly into the elastically deformable part 12 via the first washer 14.

[0055] In this embodiment, the first sleeve 13 is formed from the first washer 14, or vice versa; that is, the first sleeve 13 is connected to the first washer 14 without joints, i.e., it is monolithic. The first sleeve 13 is tubular to accommodate the screw 3 and, in the assembled state of the device, extends at least partially into the through-hole 31 of the workpiece 1. It projects beyond the first bearing surface 8 by a greater than zero dimension, thus extending into the through-hole 31. Like the first washer, the first sleeve 13 is made of a metallic material and counteracts and limits the deformation of the elastically deformable part 12 of the first perforated disc 6 in the radial direction towards the axis of the through-hole 31. It can also be bonded to the elastically deformable part 12 of the first perforated disc 6.

[0056] The elastically deformable part 12 has the first protrusion 15. This first protrusion 15 also projects beyond the first bearing surface 8 by a dimension greater than zero and extends into the through-bore 31. In this embodiment, the first protrusion 15 has the same dimensions as the portion of the first sleeve 13 that projects beyond the first bearing surface 8. Thus, the first protrusion, together with the first sleeve 13, forms the first end face 25 of the first perforated disc 6, which projects into the through-bore in the illustrated assembly position of the device. The first protrusion 15 is also hollow and cylindrical. Its outer diameter is equal to or smaller than the inner diameter of the through-bore 31 – here slightly smaller to allow for a small radial clearance between the through-bore 31 and the first perforated disc 6. Besides a clearance fit, a transition or interference fit is also conceivable.The inner diameter of the first protrusion 15 is in turn approximately the same as the outer diameter of the first sleeve 13.

[0057] The second perforated disc 7 comprises a vibration-damping, elastically deformable part 17, a second sleeve 18, a second washer 19 and a second washer 21 with a collar 22.

[0058] The second washer 19 is located on the side opposite the second bearing surface 9 of the second perforated disc 7, and thus, in the illustrated mounting position, on the side of the second perforated disc 7 facing away from the second contact surface 11 of the workpiece 1. The cage nut, acting as the threaded carrier 5, rests against the second washer 19. Analogous to the above, the second washer 19 reliably transmits the forces acting on the threaded carrier 5 to the substrate – here, the elastic part 17 of the second perforated disc 7. However, in this embodiment, the second washer 19 is not connected to the second sleeve 18. A small gap exists between the second sleeve 18 and the second washer 19. Both the second sleeve 18 and the second washer 19 are connected only to their respective elastically deformable parts 17.

[0059] The second sleeve 18 also projects beyond the second support surface 11 and, in the assembled state, extends into the through-hole 31 through the workpiece 1. As with the first perforated disc 6, the second perforated disc 7 also has a protrusion 20 of the elastically deformable part 17, which also projects into the through-hole 31 and at least partially surrounds the second sleeve 18.

[0060] Furthermore, the second bearing surface 9 of the second perforated disc 7 is formed, at least partially, by a ring-shaped washer 21, which in turn can be connected to the elastic part 17, for example, by an adhesive bond. The washer has a collar 22 that points away from the second washer 19 and thus projects into the through-hole 31, at least partially enclosing the second protrusion 20. The collar 22 is correspondingly tubular and can form a clearance or transition fit with the through-hole. The washer 21 and collar 22 can, in turn, be manufactured in one piece, for example, as a pressed or deep-drawn part.

[0061] In this embodiment, the collar 22 and the second protrusion 20 do not extend as far as the second sleeve. Therefore, only the second sleeve 18 forms the second end face 26 of the second perforated disc 7, which projects into the through-bore 31 in the illustrated assembly position of the device.

[0062] In the specified, intended mounting position and in a relaxed state of the perforated discs 6 and 7, i.e., without any axial preload applied by the screw connection via the screw 3 and the threaded carrier 5, the distance 27 between the second end face 26 of the second sleeve 18 and the first end face 25 of the first perforated disc 6 is a specified dimension greater than zero. This distance 27, also referred to as the clamping gap, will be discussed in more detail below.

[0063] Due to the design shown here, the perforated discs 6 and 7 can be described as rubber-metal elements.

[0064] The workpiece 1 has a first recess in the area of ​​the through-hole 31 for receiving the first perforated disc 6 and a second recess in the area of ​​the through-hole 31 for receiving the second perforated disc 7. The base of the first recess serves as the first contact surface 10 for the first perforated disc 6 with its bearing surface 8. The side surfaces 23 of the first recess limit any possible radial expansion of the first perforated disc 6. They at least partially surround the first perforated disc 6. In the area of ​​the first contact surface 10, the first side surfaces 23 have a relief groove 30. Similarly, in the abutment area of ​​the base of the second recess, which is designed as the second contact surface 11 complementary to the second bearing surface 9 of the second perforated disc, a relief groove 30 is provided on the second side surfaces 24 of the second recess.

[0065] Without the relief grooves 30, the recesses could also be described as blind holes, with essentially flat bottoms perforated by the through hole 31 as bearing surfaces and with inner diameters larger than the outer diameters of the perforated discs to be accommodated. In the specified, intended mounting position and in a relaxed state of the perforated discs 6 and 7, the axes of the blind holes and the through hole 31 through the workpiece, as well as the through holes through the perforated discs which are centrally mounted and aligned in the respective recess, coincide.

[0066] To allow free radial expansion of at least the elastically deformable parts 12 and 17 of the first and second perforated discs 6 and 7, a free space exists in the radial direction to the axis of the through-holes through the perforated discs 6 and 7. Here, the first and second perforated discs 6 and 7, in their predetermined, intended mounting position and in a relaxed state, have radial play in their respective recesses in the workpiece 1. The distances 28 and 29 between the first perforated disc 6 and the first side surface 23, as well as between the second perforated disc 7 and the second side surface 24, each have a predetermined dimension greater than zero.

[0067] This dimension can be selected such that, when a predetermined axial preload force is applied by means of the screw 3 via the screw head 4 and the threaded carrier 5, the radially elastically deformed first and second perforated discs 6 and 7 bear against the corresponding first and second side surfaces 23 and 24 of the recesses. The elastic deformation in the radial direction is caused by the preload in the axial direction. The free radial expansion of the perforated discs 6 and 7 is then limited by the side surfaces 23 and 24 of the recesses.The respective distances 28 and 29 between the side surfaces 23 and 24 and the corresponding perforated discs 6 and 7 can be dimensioned and adapted to the dimensions and strength of the perforated discs 6 and 7, in particular their elastically deformable parts, such that, with a given axial preload from the bolted connection, the deformed perforated discs 6 and 7 bear against the respective side surfaces 23 and 24 under a given tension. The preload applied to the bolted connection is selected and determined accordingly to ensure secure mounting of the device on the component even under given operating conditions throughout its service life.Here, the dimensions of the distances of the side surfaces 23 and 24 to the corresponding perforated discs 6 and 7, as well as the distance 27 between the end faces 25 and 26 of the first and second perforated discs 6 and 7 (clamping gap) in the specified, intended assembly position and in a relaxed state of the perforated discs 6 and 7, are coordinated with each other and further dependent on the strength, in particular the Shore hardness, of the perforated discs 6 and 7, so that with a specified axial preload from the screw connection the clamping gap is closed, i.e. the end faces 25 and 26 abut each other, possibly pressed together under specified tension, and the deformed perforated discs 6 and 7 abut the respective side surfaces 23 and 24 under specified tension.The axial deformation of the washers, screws, and sleeves can be neglected here due to their greater strength or included in the calculation. The clamping gap existing between the opposing, facing sleeve ends of the perforated discs 6 and 7 in the specified, intended assembly position and in a relaxed state of the perforated discs 6 and 7 is closed by the axial preload from the screw connection via the screw 3 and the threaded carrier 5 and by the elastic deformation of at least the elastically deformable parts of the perforated discs 6 and 7. A predetermined elastic deformation in the axial direction of the perforated discs 6 and 7 is not exceeded.

[0068] The device is sketched in the figure in the specified mounting position, but without preload from the screw connection. The perforated discs 6 and 7 are therefore still shown in their relaxed state.

[0069] The first recess is deep enough to completely accommodate and countersink the first perforated washer 6. Only the screw head 4 protrudes slightly from the first recess. The depth of the second recess, however, is dimensioned such that the second perforated washer 7 extends beyond it. The thickness of the second perforated washer 7 between its second bearing surface 9 and the surface of the second washer 19 that rests against component 2 is greater than the depth of the second recess and thus greater than the height of the second side surfaces 24 of the second recess. This prevents direct contact between component 2 and workpiece 1. This applies both in the relaxed state of the second perforated washer 7 and in the pre-tensioned, installed state of the second perforated washer 7.

[0070] In the area of ​​the second recess, workpiece 1 also has a circumferential projection 32 on the second side surfaces 24 for receiving the second perforated disc 7. The second perforated disc 7 and the projection 32 form an interference fit. This clamps the second perforated disc 7 in the second recess and thus secures it against rotation. Radial expansion of the second perforated disc 7 is therefore only prevented in the area of ​​the projection. However, this area is small compared to the depth of the second recess or the height of the side surfaces 24 of the second recess. In addition to an annular projection, point clamping could also be achieved via lug-shaped projections. This clamping prevents the second perforated disc 7 from rotating relative to workpiece 1.

Claims

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.