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1. EP2307167 - METHOD AND TOOL FOR PRODUCING A FIXED CONNECTION TO COMPONENTS JOINED IN A FORM-FITTED MANNER

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

Claims

1. A method for joining hemmed flanges of exterior component parts of car bodies in a material lock, wherein:

a) a joining electrode (1) is pressed in an acting direction (W) against a hemming flange (13) of the first component part (3) with a joining pressure (P3);

b) an earth electrode (2) is pressed in the same acting direction (W) against a second component part (4), a component part edge of which protrudes into a hem slot formed by the first component part (3) by means of the hemming flange (13);

c) the component parts (3, 4) are locally joined thermally in a material lock in the region of contact with the joining electrode (1);

d) the joining electrode (1) is moved into contact with the hemming flange (13) and pressed against the hemming flange (13) with a first contact pressure (P1);

e) and the earth electrode (2) is moved into contact with the second component part (4) and pressed against the second component part (4) with a second contact pressure (P2);
characterised in that

f) the component parts (3, 4) are in full-faced contact in the region of the hemming flange (13) while they are being joined in a material lock,

g) the contact pressure (P1) with which the joining electrode (1) presses against the first component part (3) is increased to the joining pressure (P3), while the earth electrode (2) continues to press against the second component part (4),

h) and the component parts (3, 4) are joined in a material lock at the joining pressure (P3) by energy introduced by means of the electrodes (1, 2).


  2. The method according to Claim 1, wherein the component parts (3, 4) are joined in the region of contact with the joining electrode (1) by pressure welding, preferably resistance welding, preferably before a hem glue (8), which is optionally provided in the hem slot, cures.
  3. The method according to any one of the preceding claims, wherein the joining process is performed in such a way that a hem glue (8) provided in the hem slot is hardened in the region of contact with the joining electrode (1) without welding the component parts (3, 4) in the region of contact, wherein the first component part (3) and preferably also the second component part (4) preferably consists of a light metal material at least in the region of the hemming flange (13).
  4. The method according to any one of the preceding claims and at least one of the following features:

- while the method is being performed, the component parts (3, 4) are geometrically orientated in a target position with respect to each other by a tensing device and optionally also a receptacle device (14);

- while the method is being performed, the component parts (3, 4) are arranged in the hemming bed (14) of a hemming process which forms the hem slot;

- the method is performed by means of an industrial robot which positions the electrodes (1, 2) relative to the component parts (3, 4) for joining.


  5. The method according to any one of the preceding claims, wherein a joining tool comprising the electrodes (1, 2) is arranged, in combination with a roll-hemming tool, stationarily or on an actuator which can be spatially moved, preferably the arm of an industrial robot, and the roll-hemming process and the process of joining in a material lock are performed in a combined processing run along the length of the hemming flange (13) or in direct succession in separate processing runs.
  6. The method according to any one of the preceding claims, wherein the process of joining in a material lock is integrated into a roll-hemming process in such a way that the roll-hemming process is paused at a predetermined point, in order to locally perform the joining process, and respectively continued after the joining process, and this sequence of roll-hemming and joining in a material lock is repeated until the hemmed connection and the joined connections are complete.
  7. The method according to any one of Claims 1 to 5, wherein the process of joining in a material lock is integrated into a roll-hemming process in such a way that a joining tool comprising the electrodes (1, 2) is arranged, in combination with a roll-hemming tool, stationarily or on an actuator which can be spatially moved, preferably the arm of an industrial robot, and the joining electrode (1) is embodied as a rolling member and the earth electrode (2) is embodied as a rolling or sliding member, preferably a brush or fabric belt, and the electrodes (1, 2) are held continuously in contact with the component parts (3, 4) during the ongoing roll-hemming process or are merely moved into contact with the component parts (3, 4) at predetermined points, in order to join the component parts (3, 4) in a material lock at the predetermined points.
  8. The method according to any one of the preceding claims, wherein the steps (f) and (g) are performed successively, with step (f) before or after step (g).
  9. The method according to any one of the preceding claims, wherein the first contact pressure (P 1) is kept constant for a holding time period of greater than 0 before it is increased to the joining pressure (P 3), and the earth electrode (2) is pressed against the second component part (4) during or even before the holding time.
  10. The method according to any one of the preceding claims, wherein the joining pressure (P 3) of the joining electrode (1) is selected from the range of 5 to 150 N/mm 2, wherein the joining electrode (1) is preferably pressed against the first component part (3) with a force of between 50 and 250 N.
  11. A processing tool for joining hemmed flanges of exterior component parts of car bodies in a material lock and preferably for performing the method according to any one of the preceding claims, said processing tool comprising:

a) a base (5, 17) which is arranged stationarily or is or can be docked with an actuator which can be spatially moved;

b) a joining electrode (1) and an earth electrode (2) which are arranged on the base (5, 17) with the same acting direction (W), such that the electrodes (1, 2) can be jointly pressed in the acting direction (W) against component parts (3, 4) to be joined;

c) wherein the joining electrode (1) can be moved relative to the base (5, 17) in and counter to the acting direction (W) and charged, by means of a servo unit (6), with a force in the acting direction (W) which is variable in magnitude, either continuously or in predetermined increments, or with a pressure which generates such a force;
characterised in that

d) the joining electrode (1) and the earth electrode (2) are arranged such that they can be moved relative to each other on the base (5, 17) in the acting direction (W), such that the joining electrode (1) can be pressed against one of the component parts (3, 4) to be joined with a first contact pressure at a joining point, while the earth electrode (2) is without contact, and the earth electrode (2) can then be pressed against another of the component parts (3, 4) to be joined and, once this state has been established, the contact pressure of the joining electrode (1) can be increased to a joining pressure.


  12. The processing tool according to the preceding claim, characterised in that the earth electrode (2) can be moved relative to the base (5, 17) in and counter to the acting direction (W), and a device (11) is provided for charging the earth electrode (2) with a force, preferably a spring force, which acts in the acting direction (W).
  13. The processing tool according to any one of the preceding claims and at least one of the following features:

(i) at least one of the electrodes (1, 2), and if only one of the electrodes (1, 2) then the joining electrode (1), is a rotatably mounted roller;

(ii) the processing tool comprises a medium-frequency transformer (7) for supplying energy to the electrodes (1, 2).


  14. The processing tool according to any one of the preceding claims, characterised in that a contact area (A 1) of the joining electrode (1) which is in contact with a component part during the joining process is smaller than 20 mm 2 and is preferably selected from the range of 1 to 13 mm 2, wherein a maximum extent of the contact area (A 1) preferably measures 4 mm, more preferably 1 to 3 mm, at most.
  15. The processing tool according to any one of the preceding claims and at least one of the following features:

(i) the earth electrode (2) comprises a contact (16) which is inherently flexible and which forms a contact area (A2) which is in contact with a component part during the joining process, wherein the contact is preferably elastically flexible, preferably in at least the acting direction (W);

(ii) the earth electrode (2) can be moved transverse to the acting direction (W) relative to the joining electrode (1), in order to be able to vary the location of the contact between the earth electrode (2) and the second component part (4) relative to a joining point of the joining electrode (1).


  16. The processing tool according to any one of the preceding claims, further comprising an abutment (21) which is supported on the base (5, 17) and forms a receptacle for the component parts (3, 4), opposite a contact area (A 1) of the joining electrode (1) in the acting direction (W), and absorbs the joining pressure (P 3) exerted by the joining electrode (1) on the component parts (3, 4) during the joining process and ensures a flow of force, which is closed within the processing tool via a joining point of the component parts (3, 4), during the joining process.