DE29510274U1 - Device for welding metal parts using ultrasound - Google Patents

Description

Dipl.-Phys. Dr. &EEgr;.-&EEgr;. Stoffregen Page

Patent Attorney-European Patent Attorney

Schunk Ultrasound Technology GmbH
Main Street 93

35435 Wettenberg

Description

Device for welding metal parts using ultrasound

The invention relates to a device for welding metal parts by means of ultrasound, in particular an ultrasonic roll seam welding device, comprising an oscillator unit with a sonotrode with a sonotrode head and a holder that holds the oscillator unit, wherein the sonotrode can be lowered onto or lifted off the metal parts to be welded.

In order to weld metal parts linearly rather than at specific points using ultrasound, so-called roll seam welding devices are used, in which the sonotrode is moved along the parts to be welded. Alternatively, it is possible to mount the sonotrode so that it can rotate but is stationary and to guide the metal parts past the sonotrode. In order to be able to react to unevenness in the material to be welded, the corresponding sonotrodes are guided linearly perpendicular to the material to be welded using a ball or roller guide. This allows

23 June 1995-35287B/mu

Dipl.-Phys. Dr. &EEgr;.-&EEgr;. Stoffregen Page

Patent Attorney-European Patent Attorney

However, bending moments occur which make it impossible or difficult to adjust the sonotrode, so that the weld quality does not always meet the requirements.

The present invention is based on the problem of developing a device of the type mentioned at the outset in such a way that the sonotrode can be easily guided along the course of the material to be welded, regardless of whether there are uneven surfaces or a predetermined geometric course has to be observed.

The problem is essentially solved according to the invention in that the sonotrode can be pivoted about a first axis running perpendicular to the sonotrode's longitudinal axis relative to the holder and by means of an adjustment device extending from the holder in such a way that constant or largely constant feed forces can be introduced from the sonotrode head onto the parts to be welded.

According to the invention, the sonotrode, the booster and the converter comprising the oscillator unit are arranged in a quasi-oscillating manner, so that the sonotrode head can be easily adjusted to the course of the parts to be welded, whereby the feed force can be adjusted by means of the adjustment device in such a way that it remains constant regardless of the course of the materials.

This is achieved in particular by the fact that the adjustment device can be pivoted by means of a differential pressure-operated cylinder which is articulated to the holder about a second axis running parallel to the first axis and whose piston is articulated to the sonotrode or a housing accommodating it about a third axis which runs parallel to the first and second axes.

The differential pressure-operated cylinder can be controlled via proportional valves, so that it is ensured that even if the sonotrode is stopped due to a change in the course

23 June 1995-35287B/mu

Dipl.-Phys. Dr. H.-H. Stoffregen Page

Patent Attorney-European Patent Attorney

of the material to be welded is pivoted, constant feed forces can be introduced into the material via the sonotrode using the cylinder. In addition, it is intended that the elements causing the pivoting or oscillation of the sonotrode are connected via a play-free mechanism so that the desired and reproducible conditions are always present.

The device according to the invention enables a sensitive adjustment to height or thickness differences or desired changes in the shape of the components. At the same time, tolerance-related device inaccuracies are compensated.

In a further development of the invention, it is provided that the oscillating unit is mounted in a housing so as to be rotatable about its longitudinal axis, from which pins extend which are mounted in the holder and define the first axis, which in turn preferably runs at or approximately at the center of gravity of the oscillating unit or of the housing and oscillating unit.

The support of the oscillator unit relative to the housing itself is preferably done via radial bearings.

Further details, advantages and features of the invention emerge not only from the claims, the features to be derived therefrom - individually and/or in combination - but also from the following description of an embodiment to be taken from the drawing.

Show it:

Fig. 1 is a side view of an ultrasonic roll seam welding device and

23 June 1995-35287B/mu

Dipl.-Phys. Dr. H.-H. Stoffregen Page

Patent Attorney-European Patent Attorney

Fig. 2 the ultrasonic roll seam welding device according to Fig. 1, partially

broken away.

The figures show, purely in principle, an ultrasonic roller seam welding device (10) which comprises an oscillator unit (12), a housing (14) accommodating the latter, and a holder (16) referred to as a base plate, which in turn extends from a support bracket (18) which is fastened to a carriage (not shown) in order to be able to move the entire ultrasonic roller seam welding device (10) into or out of the plane of the drawing.

The oscillator unit (12) consists in a known manner of a converter, booster, sonotrode (20) and sonotrode head (22), by means of which metal parts not shown are to be welded. For this purpose, the sonotrode (20) is set in vibration in the longitudinal direction, i.e. along the longitudinal axis (24). At the same time, the oscillator unit (12), which is mounted in the housing via radial bearings (26), (28) so that it can rotate about its longitudinal axis (24), is set in rotation. For this purpose, a servo motor (32) extends from the housing (14) or struts connected to it, which rotates the oscillator unit (12) via a toothed belt (34). The servo motor (32) has a plug connection (36) for the power supply.

According to the invention, the housing (14) and thus the oscillator unit (12) can be pivoted or tilted relative to the holder (16) about a first axis (38) running perpendicular to the longitudinal axis (24) of the oscillator and preferably horizontally, in order to be able to adjust the sonotrode head (22) sensitively to the course of the materials to be welded, so that the same feed forces can always be introduced via the sonotrode head (22) regardless of, for example, differences in height or thickness of the components. For this purpose, the housing (14) and thus the oscillator unit (12) are pivotally mounted relative to the holder (16) via a differential pressure-operated cylinder (39) which is articulated to the base plate (16) about a second axis (40). The second axis (40) runs

23 June 1995-35287B/ITIU

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Dipl.-Phys. Dr. H.-H. Stoffregen Page

Patent Attorney-European Patent Attorney

parallel to the first axis (38).

The differential pressure-operated cylinder (39), which is actuated by two proportional valves (not shown), is in turn connected to the housing (14) or the struts via its piston (42) in an articulated manner about a third axis (44) which runs parallel to the first and second axes (38) and (40), so that the sonotrode head (22) can be adjusted depending on the position of the piston (42). This adjustment is indicated by the double arrow (46) on the sonotrode head (22).

In order to be able to pivot the oscillating unit (12), pins (48) and (50) extend from the housing (14) and are mounted in sections of the bracket (16). The first axis (38) runs at or approximately at the center of gravity of the oscillating unit (12) or the oscillating unit (12) and the housing (14) including the struts (30) extending from it.

In order to enable a sensitive adjustment to the course of the parts to be welded, the differential pressure-operated cylinder (39) and the piston (42) are mounted with no play relative to the articulation points penetrated by the axes (40) and (44) by means of springs (52), (54), so that an almost instantaneous tracking of the sonotrode head (22) to the course of the parts to be welded is possible.

23 June 1995-35287B/mu

Claims (1)

Expectations Device for welding metal parts using ultrasound 1. Device (10) for welding metal parts by means of ultrasound, in particular an ultrasonic roll seam welding device, comprising an oscillator unit (12) with a sonotrode (20) and a holder (16) receiving a sonotrode head (22), wherein the sonotrode can be lowered onto or lifted off the parts to be welded,
characterized, that the sonotrode (20) can be pivoted about a first axis (38) running perpendicular to the sonotrode axis (24) relative to the holder (16) and by means of an adjusting device (39, 42) extending from the latter in such a way that constant or largely constant feed forces can be introduced from the sonotrode head (22) onto the parts to be welded. 23 June 1995-35287A/mu Dipl.-Phys. Dr. H.-H. Stoffregen Page Patent Attorney-European Patent Attorney 2. Device according to claim 1,
characterized, that the first axis (38) runs horizontally or approximately horizontally. 3. Device according to claim 1 or 2,
characterized, that the sonotrode or the oscillator unit (12) can be pivoted via a differential pressure-operated cylinder (39) which is articulated to the holder (16) via a second axis (40) running parallel to the first axis (38) and whose piston (42) is articulated to a housing (14) accommodating the oscillator unit about a third axis (44) which runs parallel to the first and second axes. 4. Device according to at least one of the preceding claims, characterized in that pins (48, 50) extending from the housing (14) on both sides to the oscillation unit (12) form the first axis (38) and are mounted in the holder (16). 5. Device according to at least one of the preceding claims, characterized in that the first axis (38) runs at or approximately at the centre of gravity of the oscillating unit (12). 6. Device according to at least one of the preceding claims, characterized in that the first axis (38) runs at or approximately at the centre of gravity of the unit formed by the oscillator unit (12) and the housing (14). 23 June 1995-35287A/mu Dipl.-Phys. Dr. H.-H. Stoffregen Patent Attorney-European Patent Attorney 7. Device according to at least one of the preceding claims, characterized in that the differential pressure-operated cylinder (39) can be controlled via proportional valves. 8. Device according to at least one of the preceding claims, characterized in that the cylinder (39) and its piston (42) are connected without play to the holder (16) on the one hand and to the housing (14) on the other hand. 9. Device according to at least one of the preceding claims, characterized in that the oscillator unit (12) is supported relative to the housing (14) via radial bearings (26, 28). 10. Device according to at least one of the preceding claims, characterized in that the holder (16) can be moved parallel to the first axis (38). 23 June 1995-35287A/mu