DE102013012321A1 - Microwave transmitter for use in industrial robot, has outlet opening that is sealed by metal contact springs, such that application of microwaves to outlet regions is decreased - Google Patents

Abstract

The transmitter comprises a waveguide (12) that is configured for propagating the microwaves generated by a generating unit. An outlet (14) is arranged in the waveguide, for emitting the microwaves to heat an adhesive layer which is arranged between mutually facing surfaces of an upper component (18) and a lower component (20). An outlet opening (16) is sealed by metal contact springs (24) formed of a copper-beryllium alloy, such that an application of the microwaves to the outlet regions (22) is decreased. An independent claim is included for a method for operating a microwave transmitter.

Description

The invention relates to a microwave transmitter with a generating device for generating microwaves and with a waveguide for transmitting the microwaves. Furthermore, the invention relates to a method for operating such a microwave transmitter.

From the vehicle industry, it is known to connect components in particular of the shell by adhesive joints with each other. While welding processes such as spot welding are used to join metallic components, these common methods fail to bond together components made of fiber-reinforced plastics. Also joining methods where rivets or - for example when applying the Rivtac ^® technology - are used bolts, ready when joining components made of carbon fiber reinforced plastics problems as it may lead to contact corrosion. However, these joining methods for connecting components made of fiber-reinforced plastic with non-conductive fibers can be used.

For joining components made of carbon fiber reinforced plastic (CFRP) with other CFRP components or metallic components therefore preferably adhesive bonds are used. However, the curing of the adhesive takes a certain amount of time. To ensure that the components to be joined together do not slip during the curing of the adhesive, the components are fixed during curing. This can be done, for example, by mechanical tensioning devices.

If adhesives are used for structural bonding in vehicle construction, a relatively long time is usually provided during which the adhesive is free-flowing, so that it does not harden in the application pipe between two consecutive operations of applying adhesive and thereby clogs the application pipe. Usually, therefore, a so-called "open time" of the adhesive of about 15 minutes is desired. On the other hand, it is desirable that the adhesive hardens comparatively quickly as soon as the components are joined, because then an assembly produced by bonding at least two components can be transported or further processed quickly and without additional fixing devices.

A short curing time can be achieved, for example, by using an adhesive which cures by introducing heat into it. In this case, an application tube, through which the adhesive flows, is heated during the application of the adhesive. However, this requires a very precise process management, because if the adhesive already cures in the application tube, then it clogs and must be replaced. This leads to increased costs and increased repair costs.

The fixation of components which are bonded by means of an adhesive that cures slowly at room temperature can be shortened in terms of the curing time of the adhesive when the adhesive areas are heated. However, the introduction of heating elements is often not possible in poorly accessible adhesive areas. Irradiation of the adhesive layer with electromagnetic waves through one of the components fails because metallic components and CFRP components shield the electromagnetic radiation.

The DE 10 2012 009 381 A1 describes a microwave transmitter having an outlet through which microwaves can be introduced from the side into a flat adhesive layer, which is located between two components. For this purpose, the outlet is positioned next to the adhesive layer, and the microwaves emerging from the outlet provide for heating and thus curing of the adhesive. The microwaves are thus irradiated in the plane of the mutually facing surfaces of the components to be bonded together in the adhesive layer. An outlet opening of the adhesive layer facing outlet, which is arranged on a waveguide of the microwave transmitter, in this case has the shape of a wide gap of small height. The height of this mouth-shaped gap is adapted to the height of the adhesive gap, and the outlet is arranged opposite the splice. Furthermore, the height of the outlet opening can be changed.

The DE 10 2007 000 862 A1 describes a method for connecting a holder to an aircraft component, which is formed from a fiber composite plastic. In this case, a heat-activatable adhesive material is arranged between the holder and the component consisting of the fiber composite plastic. The adhesive is activated by means of induction heat, in that an inductor generates currents and thus heat in a metallic network. The metallic mesh may in this case be arranged in the connection region or in the holder or in the component of the fiber composite plastic.

The introduction of heat into the adhesive serves to shorten the time required to cure the adhesive. By curing the adhesive, the components are fixed relative to each other, so that mechanical tensioning devices that provide for the fixation prior to curing of the adhesive can be removed.

However, the introduction of thermal heat in the adhesive layer by means of the inductor requires that the adhesive layer is easily accessible.

Object of the present invention is to provide a microwave transmitter and a method of the type mentioned, which or which allows a particularly process-reliable fixing of components.

This object is achieved by a microwave transmitter having the features of patent claim 1 and by a method having the features of patent claim 9. Advantageous embodiments with expedient developments of the invention are specified in the dependent claims.

In the case of the microwave transmitter according to the invention, an outlet opening of the outlet device is surrounded by shielding elements at least in regions. The shielding serve to reduce the operation of the microwave transmitter, an exposure of an environment of the outlet with the microwaves. This makes it very easy to ensure that legally defined radiation limits are adhered to, for example in the German Federal Emission Control Act. In addition, the adhesive can be heated so particularly process-reliable, since the protection of persons from microwaves is taken into account.

Due to the shielding elements which surround the outlet opening, the shielding of the electromagnetic microwaves can also be achieved with a small space requirement and a low use of material. At the same time, good accessibility to the components to be bonded together is maintained. In addition, no locks or gates need to be provided in the production, so that the logistics is simplified. It also reduces costs.

The shielding elements are preferably designed as metallic contact springs, which can be brought into contact with the microwaves with at least one of the components when the adhesive layer is applied. Thus, it can be particularly reliably avoided that microwaves can escape into the environment from an intermediate space between the outlet opening and the components.

As the shielding particularly well suited material, a copper-beryllium alloy has proven, from which the contact springs can be formed.

A particularly simple shielding can be achieved if the shielding elements are arranged on front sides of walls of a cage facing the components during operation of the microwave transmitter, the walls of the cage being spaced from the outlet opening. In particular, the outlet opening can be shielded in all directions. In addition, an existing microwave transmitter with such a cage can be retrofitted very easily.

The walls of the cage may be formed of a perforated plate or of a metal grid, so that they also contribute to the shielding of the microwaves.

If, according to a further advantageous embodiment, the cage has a height of 40 millimeters to 60 millimeters and a width of 130 millimeters to 170 millimeters, good accessibility to the adhesive layer is still provided, and comparatively narrow adhesive layers or adhesive seams can be made good by the outlet device reach from the side. This is especially true when the cage has a height of about 50 millimeters and a width of about 150 millimeters.

Additionally or alternatively, the shielding elements can be arranged on the outlet device. As a result, the space required for the shield space is particularly low. In addition, an increase in efficiency of the microwave transmitter can be achieved, since the shielding elements then contribute to the focusing of the microwaves. An increase in efficiency can also be observed with regard to the amount of heat used, since particularly little heat is lost to the surroundings of the outlet device and correspondingly much heat can be introduced into the adhesive layer.

The outlet opening may be delimited by four walls of the outlet device and be rectangular in cross-section. The shielding elements are then preferably arranged at least on the two longer walls of the outlet device. Thus, a radiation of microwaves in the directions is avoided, in which it could come without the provision of the shielding to an increased radiation of microwaves into the environment.

A particularly small space requirement can be achieved if an area enclosed by the shielding elements in the amount of 10 millimeters to 20 millimeters and a width of 90 millimeters to 100 millimeters. Thus, it is particularly easy to apply narrow layers of adhesive over a comparatively long length to heat generated by the microwaves. This is especially true when the area has a height of 15 millimeters and a width of 95 millimeters.

In the method according to the invention for operating a microwave transmitter, microwaves are generated by means of a generating device of the microwave transmitter. The microwaves are passed through a waveguide of the microwave transmitter. About a arranged on the waveguide outlet with an outlet opening the microwaves are emitted. By means of the microwaves, an adhesive layer is heated, which is arranged between mutually facing surfaces of a first component and a second component. In this case, an exposure of an environment of the outlet device to the microwaves is reduced by shielding elements which surround the outlet opening of the outlet device at least in regions.

This makes it possible to achieve a particularly reliable admission of the adhesive layer to the microwaves to an operator of the microwave transmitter.

The advantages and preferred embodiments described for the microwave transmitter according to the invention also apply to the method according to the invention and vice versa.

The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or in the figures alone can be used not only in the respectively specified combination but also in other combinations or in isolation, without the scope of To leave invention.

Further advantages, features and details of the invention will become apparent from the claims, the following description of preferred embodiments and from the drawings. Showing:

1 an industrial robot having a microwave transmitter for applying an adhesive layer to microwaves for rapid heating and thereby curing the adhesive layer;

2 an outlet of the microwave transmitter, wherein on an outlet opening bounding walls of the outlet contact springs are mounted, which are to be bonded with components in Appendix;

3 a graph which shows when applying the adhesive layer with the microwaves occurring heat maxima;

4 the outlet according to 2 in a perspective view of its outlet opening; and

5 another possibility of shielding the outlet with a perforated metal cage, wherein contact springs are arranged at the front ends of the cage forming walls.

1 shows one from a robot 10 handled microwave transmitter with a generating device for generating microwaves. The generating device can be designed, for example, as a Gunn diode. From the generating device, the microwaves are transmitted via a waveguide, for example a waveguide 12 , to an outlet 14 guided.

As in particular from 2 indicates the outlet 14 or such an outlet means a gap-shaped, so comparatively low and wide outlet opening 16 exhibit. From this outlet opening 16 In the operation of the microwave transmitter, the microwaves exit. The microwaves serve to heat an adhesive layer, which is between two components to be bonded together 18 . 20 located. For the components 18 . 20 it may in particular be body parts, such as a B-pillar of a motor vehicle.

The adhesive layer is between facing surfaces of the two components 18 . 20 arranged, and the microwaves are introduced from the side into the adhesive layer. In other words, the microwaves become in the plane of the facing surfaces of the components to be bonded together 18 . 20 irradiated in the gluing area. In this way, it is possible to uniformly heat the splice over the entire depth and thus to ensure rapid curing of the adhesive. Even at joints with poor accessibility can be effected by means of the microwave transmitter local activation of areas of the adhesive layer, which then cure very quickly. So is a fixation of the two components 18 . 20 secured relative to each other, and residual areas of the adhesive layer can then cure slower.

To ensure that an environment 22 the outlet 14 before being exposed to the discharge opening 16 Exiting microwaves is protected, shielding elements in the form of contact springs 24 provided, which at the two longer sides of - in this case rectangular - outlet 16 are arranged. At the in 2 partially shown microwave transmitter are the contact springs 24 to the (in 2 ) upper and lower walls 26 the outlet 14 arranged, which the outlet opening 16 to the environment 22 limit.

Out 2 It can also be seen that the microwaves in the outlet 14 also over one to one connection 28 connectable waveguide in the form of a coaxial cable can be introduced. Here are the decoupled from the coaxial cable microwaves in the outlet 14 deflected, in this case by 90 °. With such microwave beam antennas can be a particularly rapid curing of an adhesive bond, so a so-called speedbonding effect.

3 shows in a graph 30 two heat maxima 32 or so-called hotspots, which adjust when the microwaves are introduced into the adhesive layer.

From the perspective view of the outlet 14 in 4 is particularly well recognizable, like the contact springs 24 at the outlet opening 16 each on the top and bottom bounding wall 26 are arranged. Here are the contact springs 24 formed as leaf springs, which over a width 34 the outlet 14 away from each other evenly spaced on the two walls 26 are arranged. Flexible end regions of the contact springs 24 when applying the adhesive layer with the microwaves with the two components 18 . 20 brought into contact.

Out 4 Furthermore, it is particularly clear that the two are the outlet opening 16 walls bordering its broadside 26 are formed in the exit direction of the microwave V-shaped converging. A width 34 of the contact springs 24 enclosed area, ie a contact area to the components 18 . 20 , can be 95 millimeters. A distance between opposite contact springs 24 in the vertical direction, ie a height of the area, can be about 15 millimeters.

By the type of eyelashes on the walls 26 attached contact springs 24 With particularly low space requirements and a small contact surface, a particularly high level of efficiency in the irradiation of the microwaves into the adhesive layer can be achieved.

Also with respect to the amount of heat introduced into the adhesive layer by means of the microwaves can be determined with the in 4 shown outlet 14 in which the contact springs 24 right on the walls 26 the outlet 14 appropriate to achieve an efficiency increase of 70%. The contact springs 24 may be formed of a copper-beryllium alloy.

For the electromagnetic shielding of the outlet 14 according to 5 is the outlet 14 from a cage 36 surrounded, with upper and lower walls 38 as well as side walls 40 of the cage 36 are formed from a perforated plate. Front sides of the upper and lower walls 38 as well as the side walls 40 are with the contact springs 24 Mistake. Here are the contact springs 24 in the exit direction of the microwaves from the outlet opening 16 the outlet 14 over the outlet 14 above.

In arrangement of the contact springs 24 on the cage 36 These may have a slightly smaller distance from each other than in the arrangement of the contact springs 24 directly at the outlet 14 ,

A width of the cage 36 So a length of the upper and lower walls 38 , may be about 115 millimeters and a height, so a length of the side walls 40 , at about 50 millimeters. Also by a small-scale enclosure of the outlet 14 with the cage 36 which the contact springs 24 has a good shielding can be achieved. Furthermore, with such a cage 36 a microwave transmitter can be retrofitted very well.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102012009381 A1 [0007]
• DE 102007000862 A1 [0008]

Claims (9)

Microwave transmitter with a generating device for generating microwaves and with a waveguide ( 12 ) for passing the microwaves, wherein on the waveguide ( 12 ) an outlet device ( 14 ) is arranged, via which the microwaves for heating an adhesive layer can be dispensed, which between mutually facing surfaces of a first component ( 18 ) and a second component ( 20 ), characterized in that an outlet opening ( 16 ) of the outlet device ( 14 ) at least partially of shielding elements ( 24 ), by means of which an exposure to an environment ( 22 ) of the outlet device ( 14 ) is reducible with the microwaves. Microwave transmitter according to claim 1, characterized in that the shielding elements ( 24 ) are formed as metallic contact springs, which when applying the adhesive layer with the microwaves with at least one of the components ( 18 . 20 ) can be brought into contact. Microwave transmitter according to claim 2, characterized in that the contact springs are formed of a copper-beryllium alloy. Microwave transmitter according to one of Claims 1 to 3, characterized in that the shielding elements ( 24 ) at a during operation of the microwave transmitter the components ( 18 . 20 ) facing end faces of walls ( 38 . 40 ) of a cage ( 36 ) are arranged, wherein the, in particular from a perforated plate and / or a metal grid formed walls ( 38 . 40 ) of the cage ( 36 ) from the outlet opening ( 16 ) are spaced. Microwave transmitter according to claim 4, characterized in that the cage ( 36 ) has a height of 40 mm to 60 mm, in particular of about 50 mm, and a width of 130 mm to 170 mm, in particular of about 150 mm. Microwave transmitter according to one of Claims 1 to 6, characterized in that the shielding elements ( 24 ) at the outlet device ( 14 ) are arranged. Microwave transmitter according to claim 6, characterized in that the outlet opening ( 16 ) through four walls of the outlet device ( 14 ) is limited and rectangular in cross-section, wherein the shielding ( 24 ) at least on the two longer walls ( 26 ) of the outlet device ( 14 ) are arranged. Microwave transmitter according to claim 6 or 7, characterized in that one of the shielding elements ( 24 ) a height of 10 mm to 20 mm, in particular of about 15 mm, and a width ( 34 ) of 90 mm to 100 mm, in particular of about 95 mm. Method for operating a microwave transmitter, in which by means of a generating device of the microwave transmitter generates microwaves and the microwaves through a waveguide ( 12 ) are passed through the microwave transmitter, wherein the microwaves via a on the waveguide ( 12 ) arranged outlet device ( 14 ) with an outlet opening ( 16 ), and wherein by means of the microwaves an adhesive layer is heated, which between mutually facing surfaces of a first component ( 18 ) and a second component ( 20 ), characterized in that an exposure to an environment ( 22 ) of the outlet device ( 14 ) with the microwaves by means of shielding elements ( 24 ), which the outlet opening ( 16 ) of the outlet device ( 14 ) at least partially surrounded.

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