EP3180543B1 - Vibration element with decoupled component - Google Patents

Description

The present invention relates to a vibrating element, such as a sonotrode, with a component attached thereto.

In the ultrasonic processing of materials, an ultrasonic oscillating unit is used, which usually consists of a converter that converts an electrical AC voltage into a mechanical excitation, if necessary an amplitude transformer and a sonotrode. A high-frequency alternating voltage is then applied to the entire ultrasonic oscillating unit, so that the ultrasonic oscillating unit oscillates, with a standing wave forming within the sonotrode.

In the ideal case, all components of the ultrasonic oscillating unit are matched to one another in such a way that the entire ultrasonic oscillating unit has a natural frequency in the ultrasonic range, with which the ultrasonic oscillating unit can then be excited. Any other element that comes into contact with the ultrasonic oscillating unit or is even attached to it can degrade the oscillating properties of the ultrasonic oscillating unit. Therefore, as a rule, no additional components are attached to the ultrasonic oscillating unit. In addition, a great deal of effort is put into the mounting of the ultrasonic oscillating unit in order to ensure that the mounting influences the oscillating behavior of the ultrasonic oscillating unit as little as possible.

In some cases, however, it is necessary for components to be attached to a vibrating element of the ultrasonic vibrating unit. For example, the sonotrode can have an annular sealing surface that comes into contact with the material to be processed during processing. It can then be advantageous if fluid is supplied within the ring-shaped sealing surface or if a hold-down device is provided. In this case, the sonotrode has a cavity into which fluids, for example air, must be supplied during processing.

In figure 1 a prior art embodiment is shown. Here a sonotrode 1 has a centrally running cavity 2 . In order to feed air into this cavity, a bore 3 has been made in the sonotrode in the radial direction, in which a hose 4 is inserted, via which fluid can be introduced into the cavity 2 .

However, since the sonotrode 1 oscillates with an ultrasonic vibration during operation, this leads to unwanted ultrasonic processing of the tube 4, so that the tube 4 only has a limited service life. Even if the bore 3 is arranged in such a way that it is essentially located in the area of an oscillation node, the service life of such hose connections is limited in practice, so that the hose 4 has to be replaced relatively frequently. There is also the risk that the hose 4 will become detached from the sonotrode 1 during operation.

In figure 2 a second embodiment of the prior art is shown, in which a suction ring 5 is provided to ensure the connection of a hose to the cavity 2. The sonotrode shown has a circular cross-section, so that the suction ring 5 constructed like a sleeve can be arranged around the sonotrode with the aid of O-rings 6 . The O-rings 6 serve to seal an annular space formed by the annular recess 7 in the suction ring 5 in the axial direction, ie upwards and downwards in the figure. The suction ring 5 has a radially running bore in which a connecting piece 8 is arranged, on which the air hose can be attached.

Although the suction ring 5 is completely decoupled from the oscillating part, it must be precisely adapted to the sonotrode.

This solution is relatively complex and is only suitable for round sonotrodes. The arrangement that completely surrounds the sonotrode also requires more space, so that this sonotrode cannot be used for all applications.

In the U.S. 2003/066863 A1 describes a device and a method for ultrasonic welding of workpieces, wherein the liability of the sonotrode is to be reduced during the ultrasonic welding process. The sonotrode includes a contact surface onto which a fluid is applied prior to the welding process. A tube for the fluid is provided for this purpose, which must be connected to a hole in the sonotrode.

From the EP 0 778 437 A1 there is also known a tube coupling having a first tube and a second tube telescopically engageable with the first tube. The coupling further includes a spring to prevent telescopic disengagement of the second tube from the first tube and a plurality of O-rings disposed at the end of the first tube. One of the O-rings is located at the pivot point of the coupling, the pivot point being defined as the midpoint of the distance between a first point of contact and a second point of contact between the first tube and the second tube when the tubes are engaged.

Proceeding from the prior art described, it is therefore the object of the present invention to provide an oscillating element with a component attached thereto which is easy to produce, has a long service life and also prevents the component from becoming detached from the sonotrode.

According to the invention, this is achieved in that the vibration element has a bore and the component has a fastening section inserted in the bore, with an elastic element being arranged between the fastening section and the bore, which is at least partially arranged within a recess made in the inner surface of the bore so that the component can only be removed from the borehole by elastic deformation of the elastic element, the fastening section having a recess, preferably designed as a circumferential groove, in which the elastic element, which is preferably an O-ring, is arranged.

The measure described can, for example, also be introduced later in existing sonotrodes. It is only necessary that a corresponding hole is made in the sonotrode. The fastening section of a component can then be inserted into the bore, the elastic element being arranged between the fastening section on the one hand and the inner walls of the bore on the other hand. In order to prevent the fastening section from moving relative to the bore, the elastic element is designed in such a way that when inserted it is either elastically deformed or at least partially arranged within a recess made in the inner surface of the bore so that the component can only be held in place by an elastic Deformation of the elastic element can be removed from the bore.

In the simplest case, the hole has a circular cross-section. In principle, however, other cross sections, such as a square cross section, would also be conceivable.

In the same way, it is provided in a preferred embodiment that the fastening section has a circular cross section. It goes without saying, however, that the fastening section does not necessarily have to have a circular cross section, but can have a square cross section, for example. In addition, it is also not necessary for the borehole and the fastening section to have a cross section that corresponds to one another. However, it is necessary for the elastic element to be adapted both to the fastening section and to the bore.

In a preferred embodiment, the elastic element is designed to completely surround the fastening section. In the event that the bore has a circular cross-section and the fastening section has a circular cross-section, the elastic element can be ring-shaped or sleeve-shaped, so that it can be pushed over the outer surface of the fastening section and can be introduced into the bore together with it .

In order to make the connection between the vibration element and the component as tilt-resistant as possible, a preferred embodiment provides for at least two elastic elements to be arranged between the fastening section and the bore, with the two elastic elements preferably being spaced apart axially. Here axial refers to the bore axis.

Furthermore, it can be advantageous that a spacer sleeve, which encompasses the fastening section, is arranged axially between the two elastic elements.

As an alternative to this, it is also possible for the fastening section to have two axially spaced recesses, for example circumferential grooves, in which the two elastic elements are at least partially arranged.

In a further preferred embodiment, the component has a pressure element that can be moved relative to the fastening section and is designed in such a way that it can be used to exert a force on the elastic element. By exerting the force on the elastic element, this tries to give way and thus increases the force that the inner walls of the bore exert on the fastening section of the component via the elastic element.

In a further preferred embodiment, the pressure element is designed as a sleeve with an internal thread and the component has a section with an external thread on which the pressure element is arranged, the pressure element being arranged at least in sections together with the fastening section within the bore, so that rotating the pressure element relative to the component, the pressure element can be moved further into or out of the bore.

If the pressure element is now rotated relative to the fastening section so that it moves into the bore, it will eventually hit the elastic element and compress it in a direction, causing it to move in a direction that is essentially perpendicular to the direction of movement of the pressure element an expansion of the elastic element occurs, whereby the component is clamped firmly within the bore, so that unintentional loosening is prevented even in ultrasonic operation.

The component can be a compressed air supply, for example. In this case, the component is tubular, with the fastening section being provided on the outside of the tube, which is inserted into a corresponding bore in the vibrating element with the interposition of an elastic element. Alternatively, air can also be extracted via the component.

However, the fastening method described can also be used elsewhere. For example, there are sonotrodes with a ring-shaped sealing surface, so that a hold-down device is desired inside the ring-shaped sealing surface. This hold-down device must then be arranged inside the sonotrode. The sonotrode thus has a cavity and the component namely a receptacle for a corresponding hold-down device can then be arranged within the cavity. The hold-down device can be actuated, for example, with the aid of compressed air, which is also supplied by the arrangement according to the invention. Instead of the hold-down device, a damper or a suction device could also be attached inside the sonotrode.

• Figur 1 eine erste Ausführungsform des Standes der Technik,
• Figur 2 eine zweite Ausführungsform des Standes der Technik,
• Figur 3 eine Querschnittsansicht eines Bauteils einer ersten erfindungsgemäßen Ausführungsform,
• Figur 4 eine Teilquerschnittsansicht des Schwingungselementes mit eingesetztem Bauteil der ersten Ausführungsform der Erfindung,
• Figur 5 eine Querschnittsansicht eines Bauteils einer zweiten Ausführungsform der Erfindung,
• Figur 6 eine Detailansicht eines Querschnitts eines Schwingungselementes mit eingesetztem Bauelement gemäß der zweiten Ausführungsform der Erfindung,
• Figur 7 eine Querschnittsansicht eines Bauteils einer dritten Ausführungsform der Erfindung,
• Figur 8 eine Detailansicht eines Querschnitts des Schwingungselementes mit eingesetztem Bauelement gemäß der dritten Ausführungsform der Erfindung,
• Figur 9 einen Querschnitt durch ein Schwingungselement gemäß der vierten Ausführungsform der Erfindung,
• Figur 10 eine Querschnittsansicht gemäß Figur 9, jedoch zusätzlich mit Luftdruck betriebenem Niederhalter.

Further advantages, features and application possibilities become clear based on the following description of preferred embodiments and the associated figures. Show it:

• figure 1 a first embodiment of the prior art,
• figure 2 a second embodiment of the prior art,
• figure 3 a cross-sectional view of a component of a first embodiment according to the invention,
• figure 4 a partial cross-sectional view of the vibrating element with inserted component of the first embodiment of the invention,
• figure 5 a cross-sectional view of a component of a second embodiment of the invention,
• figure 6 a detailed view of a cross section of an oscillating element with an inserted component according to the second embodiment of the invention,
• figure 7 a cross-sectional view of a component of a third embodiment of the invention,
• figure 8 a detailed view of a cross section of the vibrating element with inserted component according to the third embodiment of the invention,
• figure 9 a cross section through an oscillating element according to the fourth embodiment of the invention,
• figure 10 a cross-sectional view according to FIG figure 9 , but additionally with air pressure operated hold-down device.

In the Figures 1 and 2 two prior art embodiments are shown which have already been described above.

In figure 3 1 is a cross-sectional view of a component of a first embodiment of the invention. The component 9 is essentially tubular with a central channel 14 . The component 9 has a fastening section 11 and a threaded section 10 . A corresponding hose for supplying compressed air can be attached to the threaded section 10 . The attachment section 11 has two O-rings 12,13 which are arranged in corresponding grooves 15,16.

In figure 4 a detailed view is shown which shows the interaction between the component 9 on the one hand and the vibration element 1 on the other hand. The vibration element 1 , for example a sonotrode, has a bore 3 . The fastening section 11 is introduced into the bore 3 together with the two O-rings 12, 13. In order to hold the component 9 securely in the bore 3, a groove 17 is provided in the inner wall of the bore 3, in which the O-ring 12 is held. The two provided on the mounting portion 11 have grooves 15, 16 for receiving the two O-rings 12, 13, as shown in FIGS Figures 3 and 4 clearly recognizable is a different groove depth. It was taken into account that the O-ring 12 has a corresponding groove 17 on the vibration element 1, while this is not the case for the second O-ring 13. In order to keep the force distribution between the two O-rings essentially the same, the depth of the groove 16 is dimensioned such that it corresponds to the sum of the groove depths of the groove with a smaller depth 15 of the component 9 and the depth of the groove 17 in the vibrating element .

in the in figure 4 In the state shown, the component is adapted to be essentially vibration-decoupled within the vibration element 1 . Unintentional displacement of the component 9 within the bore 3 is prevented in that the O-ring 12 engages both in a recess 15 in the component 9 and in a recess 17 in the vibration element 1 .

In figure 5 1 is shown a sectional view of a second embodiment of the present invention. Wherever possible, like reference numerals have been used to designate like elements.

Essentially, the differs in figure 5 shown embodiment of the component from the in figure 3 shown embodiment characterized in that on the one hand the groove depth for the two O-rings 12, 13 is the same. In addition, the component 9 ′ here also has a pressure element 18 which is attached to the external thread 10 of the threaded section with the aid of an internal thread. By rotating the pressure element 18 relative to the component 9', the pressure element 18 can be moved in the axial direction towards the O-ring 12 and away from it.

The pressure element 18 is sleeve-shaped and has an axially projecting neck section 19 which comes into contact with the O-ring 12 facing the pressure element 18 . To this end, the neck portion has an outside diameter that is smaller than the inside diameter of the bore. The groove for accommodating the O-ring 12 is thus formed both by the component 9 ′ and by the pressure element 18 or the projecting collar element 19 . In figure 6 is a detailed view shown in which the interaction of the component 9 'with the Vibration element 1 is illustrated. Here, too, the vibration element 1 has a bore 3 in which a circumferential groove 17 for receiving the O-ring 12 is introduced.

In order to ensure in this embodiment that the two O-rings 12, 13 exert substantially comparable forces on the inner surfaces of the bore 3 of the vibrating element 1, the pressure element 18 is rotated relative to the threaded section 10 in the situation shown to the groove width in which the O-ring 12 is inserted, whereby the O-ring 12 deforms and expands in the radial direction, which in turn causes the O-ring to come into contact with the groove bottom of the groove 17 in the vibrating element 1. The O-ring 12 is pressed against the groove 17 by the pressure element 18, so that it is ensured during operation that the component 9' in the axial direction can neither be moved in the direction of the sonotrode nor away from it.

In figure 7 a component 9" of a third embodiment of the invention is shown. In contrast to that in figure 5 shown component 9 'a spacer sleeve 20 is provided here. If the pressure element 19 is now rotated relative to the threaded section 10 , the pressure element 18 moves in the direction of the first O-ring 12 so that it is clamped between the neck section 19 of the pressure element 18 and the spacer sleeve 20 . Since the spacer sleeve 20 is also movably arranged, it is moved in the direction of the second O-ring 13 so that a force can be exerted on both the first O-ring 12 and the second O-ring 13 with the aid of the pressure element 18 .

As in figure 8 , which shows the inserted state, it is possible to dispense with the provision of a groove in the inner wall of the bore in this embodiment. Due to the uniform application of the pressure force of the pressure element 18 to the two O-rings, a uniform application of force via the two O-rings 12 and 13 is ensured in this case even without the provision of a groove. Of course, one or more grooves can also be provided in this embodiment, in which an O-ring or both O-rings engage.

In figure 9 a cross-sectional view of a fourth embodiment is shown. Here, the sonotrode 1 has an essentially ring-shaped welding surface 31 which comes into contact with the material to be processed during the ultrasonic processing. A cavity 32 is therefore formed inside the sonotrode. Depending on the application, it can be helpful if, while the ring-shaped welding surface 31 comes into contact with the material to be processed, a hold-down device presses the material down inside the ring-shaped welding surface. This hold-down device can also be attached to the sonotrode 1 in a vibration-decoupled manner.

For clarification is in figure 9 only a sleeve 21 with an inner channel 27 is shown, which is mounted vibration-decoupled within the sonotrode 1 . This sleeve 21 is arranged inside a second sleeve 33 and connected to it via a screw connection. Furthermore, two O-rings 22 and 24 and a spacer sleeve 23 are provided. If the sleeve 21 is now rotated relative to the second sleeve 33 , this results in the protruding section of the sleeve 21 pressing the O-ring 22 against the spacer sleeve 23 , which in turn exerts a force on the second O-ring 24 . As a result, the two O-rings are deformed so that they expand in the radial direction and the sleeve 21 is jammed inside the sonotrode 1 . The longitudinal bore in the sonotrode is stepped so that the O-ring 24 comes to rest on the step of the bore, as a result of which movement of the sleeve downwards, ie in the direction of the sealing surfaces 31, is prevented.

In order to prevent movement in the opposite direction, a further pressure element 26 is provided which has an internal thread which engages with an external thread of the second sleeve 33 and thus elastically deforms a third O-ring 25, which in turn ensures that the connection cannot move axially upwards.

In figure 10 is now additionally shown that the second sleeve 33 is connected to a housing 30, the bottom of which is closed by means of a piston 28, which can be spring-biased. A cavity 29 is thus formed in the housing 30, so that it is now possible to apply force to the piston 28 with the aid of compressed air, which is supplied via the bore 3 and is guided via the channel 27 into the cavity 29, so that it moves axially is moved down and can hold the material to be processed accordingly.

Due to the measure according to the invention, a vibration-decoupled connection of components with vibration elements is possible.

Reference List

1

sonotrode

2, 29, 32

cavity

3

drilling

4

tube

5

suction ring

6, 12, 13, 22, 24, 25

o-rings

7

annular recess

8th

connecting piece

9, 9', 9"

component

10

threaded section

11

attachment section

14, 27

channel

15, 16, 17

grooves

18, 26

pressure element

19

collar element

20, 23

spacer sleeve

21, 33

sleeve

28

Pistons

30

housing

31

welding surface

Claims (10)

1. A vibration element (1) like for example a sonotrode (1) with a component (9, 9', 9") fixed thereto, wherein the vibration element (1) has a bore (3) and the component (9, 9', 9") has a fixing portion (11) fitted in the bore (3), wherein arranged between the fixing portion (11) and the bore (3) is an elastic element (12, 13, 22, 24) which is arranged at least partially within a recess (17) provided in the inside surface of the bore (3) in such a way that the component (9, 9', 9") can be removed from the bore (3) only by elastic deformation of the elastic element (12, 13, 22, 24), characterised in that the fixing portion (11) has a recess which is preferably in the form of a peripherally extending groove (15, 16) and in which the elastic element (12, 13, 22, 24) which is preferably an O-ring is arranged.
2. A vibration element (1) as set forth in claim 1 characterised in that the bore (3) is of a circular cross-section.
3. A vibration element (1) as set forth in claim 1 or claim 2 characterised in that the fixing portion (11) is of a circular cross-section.
4. A vibration element (1) as set forth in one of claims 1 through 3 characterised in that the elastic element (12, 13, 22, 24) is arranged to completely surround the fixing portion (11).
5. A vibration element (1) as set forth in claim 4 characterised in that at least two elastic elements (12, 13, 22, 24) are arranged between the fixing portion (11) and the bore (3), wherein preferably the two elastic elements (12, 13, 22, 24) are axially spaced from each other.
6. A vibration element (1) as set forth in claim 5 characterised in that arranged axially between the two elastic elements (12, 13, 22, 24) is a spacer sleeve (20, 23) which embraces the fixing portion (11).
7. A vibration element (1) as set forth in one of claims 1 through 6 characterised in that the component (9, 9', 9") has a pressure element (18, 26) which is moveable relative to the fixing portion (11) and which is so designed that a force can be exerted therewith on the elastic element (12, 13, 22, 24).
8. A vibration element (1) as set forth in claim 7 characterised in that the pressure element (18, 26) is in the form of a sleeve with a female thread and the component (9, 9', 9") has a portion (10) with a male thread, on which the pressure element (18, 26) is arranged, wherein preferably the pressure element (18, 26) is arranged at least portion-wise together with the fixing portion (11) within the bore (3) so that the pressure element (18, 26) can be moved further into the bore (3) or out of the bore by rotation of the pressure element (18, 26) relative to the component (9, 9', 9").
9. A vibration element (1) as set forth in one of claims 1 through 8 characterised in that the component (9, 9', 9") is an air feed or air discharge means.
10. A vibration element (1) as set forth in one of claims 1 through 8 characterised in that the vibration element (1) has a cavity (2, 29, 32) and the component (9, 9', 9") is arranged within the cavity (2, 29, 32), wherein preferably the component (9, 9', 9") is a hold-down means, damper or suction means.

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