This application is a national stage of, and claims priority to, Patent Cooperation Treaty Application No. PCT/EP2018/052998, filed on Feb. 7, 2018, which application claims priority to German Application No. DE 10 2017 001 780.8, filed on Feb. 24, 2017, which applications are hereby incorporated herein by reference in their entireties.
The disclosure concerns an applicator for applying a coating agent (e.g. sealant) to a component (e.g. motor vehicle body component), in particular for sealing or bonding a flanged seam on a motor vehicle body component. The disclosure also includes a corresponding application method.
Motor vehicle body components (e.g. doors or hoods) often have so-called flange seams in which one sheet metal part is flanged around an edge of another sheet metal part, whereby the two sheet metal parts can then be glued together. There is a risk that moisture will penetrate into the gap between the two sheet metal parts and lead to corrosion. It is therefore known to apply a sealing compound to the flanged seam between the two sheet metal parts in order to seal the flanged seam and thus reliably prevent the penetration of moisture and associated corrosion.
An applicator is known from U.S. Pat. No. 9,505,020 B2, which makes it possible to coat a flanged seam on the back of a motor vehicle door without having to open the door. This applicator has a nozzle carrier with several limbs that are angled relative to each other. This allows the nozzle carrier to pass through the gap between two adjacent, laterally overlapping motor vehicle body components (e.g. door and fender), so that the nozzle is then on the rear side and the flanged seam can be coated. This applicator usually works without contact, i.e. contact between the applicator on the one hand and the vehicle body component on the other hand should be avoided.
This contactless application method is associated with various disadvantages, which are briefly described below.
A problem with the non-contact application method is that the flanged seam to be coated is located on the rear side of the vehicle body components and is therefore not directly visible, which makes programming (“teaching”) the application paths more difficult.
In addition, the alignment of the coating nozzle relative to the component surface is not visible, but can only be guessed at, which makes programming more difficult.
The programming of the desired application path is therefore only iterative in practice. The first step is to carry out programming that is as good as possible. Then coating agents are applied with the initial programming. The application picture is then examined, for example by opening the motor vehicle door and looking at the flanging seam on the inside of the motor vehicle door. This inspection of the quality of the sealed flange seam then allows conclusions to be drawn in order to optimize the programming. For example, motion parameters of the robot and application parameters can be adjusted to optimize the coating result. This iterative optimization of the programming is carried out until the application result is satisfactory.
An alternatively possible offline programming does not solve this problem because the tolerance chains are too large when transferring offline programming to a real coating situation. In practice, the vehicle body components to be coated are conveyed by a conveyor along a paint sealing line, whereby the conveyor only has a relatively rough positioning tolerance when positioning the vehicle bodies, which leads to correspondingly large positioning inaccuracies. Added to this is the positioning tolerance of the multi-axis application robot that guides the applicator. Further influences on the tolerance chain result from the manufacturing tolerances of the respective body. Part of this tolerance chain can be eliminated by using (optical) measurement systems. These systems measure relevant body geometries, such as edges of the doors to be coated. However, these measuring methods also have limited accuracies, so that only a part of the described tolerance chain can be compensated.
Programming is therefore very time- and cost-intensive in practice.
As an alternative to the non-contact application method described above, state-of-the-art tactile application methods are also known in which the applicator is in contact with the component to be coated during application. In a manual application, for example, the operator can place a suitably designed nozzle against the edge of the door to be coated and then pull the nozzle along the edge of the component as the material leaves the nozzle opening. By placing the nozzle against the component edge, reproducible guidance is ensured. For example, the nozzle opening and thus the applied path have the same distance from the door edge. However, the nozzle carrier must be of a correspondingly stable design. This usually leads to a relatively large diameter of the nozzle needle, so that in practice it is not possible to guide the nozzle carrier through the door gap when the door is closed. In practice, the doors are therefore usually opened by the operator in order to be able to coat a flanged seam on the rear side. This also has the advantage for the operator that he can simultaneously view the quality of the application result.
Furthermore, it is known from the state of the art that this tactile process is used in conjunction with application robots that automatically guide the applicator. Here, the applicator is attached to the application robot by means of a flexible joint, whereby the flexible joint allows an evasive movement of the applicator in order to avoid mechanical overloads during contact between the applicator and the component to be coated.
These tactile procedures, which are also well known, also have certain disadvantages, which are briefly described below.
First of all, it should be noted that flanging seams on the rear side of motor vehicle doors are generally not accessible when the doors are closed if body parts overlap in these areas. The reason for this is that, for reasons of rigidity, the diameter of the nozzle carrier is usually larger than the gap width between the adjacent components.
In practice, it is therefore necessary to open the respective door in order to coat a flanged seam on the rear side of a motor vehicle door. However, this requires a cycle time which is lost for the actual application. Thus, it may not be possible to completely coat a vehicle body in one cycle, which requires further cycles and thus further investments.
In addition, an additional handling robot (“door opener”) is usually required to open and close the vehicle doors, which entails additional investment costs and additional space requirements in the paint shop.
If, on the other hand, the car body doors are opened and closed by the application robot itself, no additional handling robot is required, but gripping tools (e.g. hooks) must be attached to the application robot in order to be able to grip the door. However, these additional tools impair the actual application process and are therefore also disadvantageous. Furthermore, in this case an additional mechanical device must be installed which locks the opened door in the desired position. In addition to the additional investment costs, this also requires additional space.
Further disadvantages result from the fact that in the tactile application process the nozzle is placed directly on the flanging seam. As a result, the nozzle opening cannot rest directly on the flanged seam, but must be inclined at an angle of, for example, 45° in order to be able to apply the sealant by pulling. As a result, the energy of the spray jet when it hits the component surface is comparatively low, which can lead to flaws (e.g. air inclusions).
Furthermore, due to the contact between the nozzle and the component surface, there is a risk that the nozzle will get caught on elevations, which can be caused by welding spots or adhesive leaks, for example. This can cause the applicator to vibrate or chatter further along the application path, which also impairs the quality of the application. In the worst case, ductile deformation or breakage of the nozzle needle may occur.
Finally, no material overlap and no hem can be coated with the tactile method, which is, however, particularly necessary at component corners.
The applicator according to the disclosure initially has a mounting flange 1 that can be mounted on a multi-axis application robot.
The applicator according to the disclosure is used to apply a coating such as a sealant (e.g. PVC material; PVC: polyvinyl chloride). The term “coating agent” used in the disclosure is, however, to be understood generally and may basically also include other types of coating agent, in particular thick materials, such as insulating materials for acoustic or thermal insulation or adhesives, to name but a few examples.
It should also be mentioned that the applicator is preferably used to apply the coating (e.g. sealant) to a vehicle body component (e.g. door), in particular to seal or bond a flanged seam on the vehicle body component. However, the term “component” used in the context of the disclosure is to be understood generally and is not limited to motor vehicle body components.
In accordance with the known applicator according to U.S. Pat. No. 9,505,020 B2, the applicator according to the disclosure first has a nozzle to apply the coating agent in a certain jet direction to a component surface of the component to be coated.
In addition, in accordance with the known applicator, the applicator according to the disclosure has a nozzle carrier to position the nozzle, the nozzle carrier having multiple limbs arranged one behind the other and angled relative to each other. The individual limbs are preferably straight when viewed on their own, but the individual limbs can also be curved when viewed on their own. The nozzle mentioned above is located on the nozzle carrier and is preferably attached to the distal limb of the nozzle carrier. It should also be noted that the nozzle carrier is hollow over at least part of its length to pass the coating. In the case of the applicator according to the disclosure, the nozzle carrier serves on the one hand to convey the coating agent through and on the other hand to position the nozzle.
It was already mentioned at the beginning that the applicator according to U.S. Pat. No. 9,505,020 B2 is used for contactless application, which is associated with the problems described at the beginning. By contrast, the applicator in accordance with the disclosure is characterized by the fact that a spacer is arranged on the outside of the nozzle carrier (e.g. on the distal limb of the nozzle carrier), which projects from the distal limb in the direction of the jet and rests on the component surface of the component to be coated during coating operation, thereby setting a predetermined application distance between the nozzle and the component surface, in particular an application distance of essentially 2 mm, 3 mm, 4 mm or 5 mm, or any intermediate values.
The spacer allows the nozzle to not rest directly on the component surface—in contrast to the known tactile application methods—so that the nozzle can be aligned at right angles to the component surface with the jet direction. Use of the spacer allows the applied spray jet to hit the component surface with relatively maximized energy. In addition, the lack of contact between the nozzle on the one hand and the component surface on the other hand avoids so-called chatter marks during application.
The spacer allows the applicator with the nozzle to not stick to surface elevations caused, for example, by adhesive leaks from a flanged seam or welding spots. The application distance between the nozzle on the one hand and the component surface on the other hand may therefore be adjusted by means of the spacer so that the application distance is greater than the unevenness height of the surface elevations, which can be caused by adhesive leaks or welding spots. This is possible because the nozzle then has no contact with the surface during movement over the component surface, even at the surface elevations.
The two distal limbs of the nozzle carrier are preferably angled relative to each other and include an angle, as is the case with the applicator according to U.S. Pat. No. 9,505,020 B2. In the case of the applicator according to the disclosure, the spacer can also be used to stabilize this angle between the two distal limbs of the nozzle carrier. For this purpose, the spacer may be arranged in the angle between the two distal limbs of the nozzle carrier and connected to the two distal limbs, for example by welding, bonding or by a one-piece shaping of the spacer and the distal limbs of the nozzle carrier. The spacer thus stabilizes the two distal limbs of the nozzle carrier and prevents the two distal limbs of the nozzle carrier from bending relative to each other through the formation of a so-called bend-resistant corner.
In another example of the disclosure, the spacer is shaped in the form of an anvil and lies on the surface of the component with its anvil surface during coating operation. Here, the distal limbs of the nozzle carrier merge into one another at the angle, preferably via a pipe bend, without kinking, the spacer being connected to the pipe bend, for example by welding.
In another example of the disclosure, however, the spacer consists of an elbow piece which is arranged at the angle between the two distal limbs of the nozzle carrier and is connected to the two distal limbs, for example by welding. In this variant of the disclosure, the two distal limbs of the nozzle carrier connect to each other at the angle preferably with a kink, in particular with a right-angled kink.
With the applicator according to the disclosure, the nozzle carrier may be angled so that it can protrude through a gap between two adjacent, laterally overlapping motor vehicle body components (e.g. door and fender) from a front side to a rear side of the motor vehicle body components. The proximal limb of the nozzle carrier may then be located on the front side of the vehicle body components during coating operation and is guided there by an application robot, which is also located on the front side. The distal limb of the nozzle carrier with the nozzle, on the other hand, may be located on the rear side of the motor vehicle body component during coating operation, so that the nozzle can coat a flanged seam on the rear side, for example. In contrast, a middle limb of the nozzle carrier protrudes through the gap between the laterally overlapping motor vehicle body components from the front to the rear of the motor vehicle body components. Such a design of the nozzle carrier is known from U.S. Pat. No. 9,505,020 B2, which is fully incorporated herein by reference.
It should be mentioned here that the proximal limb of the nozzle carrier can be mechanically more stable than the distal limbs and/or the middle limb of the nozzle carrier. This is because the proximal limb is positioned at the front of the motor vehicle body components to be coated and does not have to protrude through the relatively narrow gap between the adjacent motor vehicle body components, so that there are no restrictions with regard to the external cross-section of the proximal limb of the nozzle carrier. The proximal limb of the nozzle carrier can therefore have such a large external cross-section that it does not fit through the gap between the laterally overlapping vehicle body components. Furthermore, the larger external cross-section of the proximal limb of the nozzle carrier also allows a larger internal cross-section for the passage of the coating agent, which is advantageous because the hollow channel in the proximal hollow limb of the nozzle carrier then forms a lower flow resistance for the coating agent. The proximal hollow limb of the nozzle carrier can therefore have a larger internal cross section than the distal limbs and/or the middle limb of the nozzle carrier.
It should also be mentioned that the nozzle carrier can at least partially consist of a material with a shape memory, for example a nickel-titanium alloy such as Nitinol or Titan-Flex. This material selection is particularly advantageous for the middle limb and/or the distal limbs of the nozzle carrier, since these limbs can be deformed in contact with the components to be coated. It should be mentioned here that the term shape memory used in the disclosure must be distinguished from materials which are merely elastic and return to their original position after mechanical deflection.
With the applicator according to the disclosure, the different limbs of the nozzle carrier can differ with regard to the bending stiffness. Thus, within the scope of the disclosure, it is possible that the distal limb or the two distal limbs of the nozzle carrier are more rigid than the middle limb of the nozzle carrier, which projects through the gap between the laterally overlapping vehicle body components during coating operation.
This greater bending stiffness can be achieved, for example, by increasing the wall thickness. For example, the wall thickness can be at least 0.15 mm, 0.175 mm, 0.2 mm or even at least 0.22 mm to achieve sufficient bending stiffness. On the other hand, the outer diameter is preferably a maximum of 1.75 mm, 1.7 mm or even a maximum of 1.65 mm, so that the nozzle carrier fits through the gap between the laterally overlapping vehicle body components. The inside diameter of the hollow channel in the respective limb, on the other hand, is preferably not more than 1.5 mm, 1.4 mm, 1.3 mm or even not more than 1.2 mm.
It has already been briefly mentioned above that the nozzle carrier of the applicator according to the disclosure can have a similar structure to the nozzle carrier of the conventional applicator according to U.S. Pat. No. 9,505,020 B2. For example, the nozzle carrier can have four limbs which are arranged one behind the other, lie in a common plane and are angled to each other.
The applicator can be mounted on an application robot by means of an elastically flexible joint, whereby the elastic joint enables evasive movements of the applicator in order to avoid damage to the applicator and the component to be coated in the event of excessive contact between the applicator on the one hand and the component to be coated on the other hand. The flexible joint allows the applicator to avoid movement in two spatial directions, preferably parallel to the component surface and transverse to the component surface. In coating operation, the nozzle carrier can then be placed against the component edge of the component to be coated and guided along the component edge so that the component edge guides the applicator in one spatial direction. The contact between the spacer on the one hand and the component surface on the other hand then causes the applicator to be guided in a further spatial direction.
It should be mentioned here that the elastic joint between the applicator and the application robot preferably generates a counterforce that is essentially independent of the size of the evasive movement. For example, the counterforce can be in the range of 1N-15N, 2N-10N, 3N-8N or 4N-5N.
When the applicator is moved over the component surface, the coating agent (e.g. sealant) is then released from the applicator nozzle in a specific jet direction onto the component surface, whereby the nozzle maintains a specific application distance from the component surface of the component to be coated.
With reference to the drawings, the applicator has a nozzle carrier 2 consisting of several limbs 3-6 arranged one behind the other in a common plane and angled relative to each other. The angle between the two limbs 3 and 4 and the angle between the two limbs 4 and 5 is approximately 135°. The angle between the two limbs 5 and 6, on the other hand, is preferably perpendicular. It should be noted here that the angles between the individual limbs 3-6 are such that the nozzle carrier 2 can be guided through a gap between two adjacent, laterally overlapping motor vehicle body components (e.g. door and fender). The optimum angles between the individual limbs 3-6 of the nozzle carrier 2 thus also depend on the respective component geometry of the motor vehicle body components.
A nozzle 7 is located on the distal limb 6 of the nozzle carrier 2 to dispense the sealant in the direction of the arrow.
It should also be mentioned that the limbs 3-6 of the nozzle carrier are hollow so that the sealant to be applied can be guided from the mounting flange 1 to the nozzle 7 in the distal limb 6.
The applicator according to the disclosure shown here is particularly suitable for coating a flanged seam 8 of a motor vehicle body component, where a body panel 9 is flanged around the side edge of another body panel 10 at the flanged seam 8. There is a risk of moisture penetrating this flanged seam 8, which can lead to corresponding corrosion. The flanged seam 8 is therefore coated with a sealing agent (e.g. PVC) at the joint between the two body panels 9 and 10 to prevent moisture from penetrating.
For this purpose, the applicator is placed with the limb 5 against the side edge of the flange seam 8 and then moved along the flange seam 8, i.e. in the x-direction and thus perpendicular to the drawing plane. The contact between the limb 5 of the nozzle carrier 2 on the one hand and the side edge of the flanged seam 8 on the other hand guides the applicator in the y-direction.
In addition, the applicator has a spacer 11 which is arranged at the angle between the two distal limbs 5, 6 of the nozzle carrier 2 and in this concrete embodiment consists of a tubular angle piece which is welded to both limbs 5, 6.
On the one hand, the spacer 11 mechanically stabilizes the two distal limbs 5 and 6.
On the other hand, the spacer 11 also rests directly on the component surface of the flange seam 8 during coating and thus adjusts a certain application distance a between the nozzle 7 and the component surface. The spacer 11 thus guides the applicator in the z-direction.
This is advantageous because the nozzle 7 can apply the sealant to the component surface at a right angle to the component surface so that the sealant hits the component surface with maximum flow energy.
In addition, the application distance a is also advantageous because it prevents the nozzle 7 from sticking to uneven surfaces, which can, for example, be caused by an adhesive escaping from the flange seam 8 or by welding spots.
One I feature of this embodiment is that the two distal limbs 5, 6 of the nozzle carrier 2 are not connected to each other with a right-angled bend, as in the embodiment of the
Another feature of this embodiment is that the spacer 11 is not designed as a tubular angle piece, but in the form of an anvil with its anvil surface resting on the surface of the component.
In addition to the above illustrations, this drawing also shows that a hollow channel 13 leads from the mounting flange 1 through the entire nozzle carrier to the nozzle 7 in order to pass the sealant through.
Furthermore, it can be seen from the drawing that the two body panels 9, 10 with the flanged seam 8 overlap laterally with another body panel 14, which is shown here only schematically. The applicator protrudes from the front side (in the drawing below) through the gap 15 to the rear side (in the drawing above) in order to be able to coat the flanged seam 8 on the rear side.
In addition, the drawing shows a robot arm 16 and a robot hand axis 17 of a multi-axis application robot with serial robot kinematics. The mounting flange 1 of the applicator according to the disclosure is connected to the robot hand axis 17 via an elastic joint 18, whereby the joint allows 18 evasive movements of the applicator in the y-direction and in the z-direction.
This is advantageous because the applicator with the limb 5 in the y-direction rests against the side edge of the flanged seam 8 and is thus positively guided. The joint 18 enables an evasive movement in the y-direction, thus preventing a mechanical overload of the applicator.
The possibility of an evasive movement in z-direction is advantageous, because the applicator with the spacer 11 rests on the component surface and is therefore positively guided in z-direction, which could lead to mechanical overloads without a compensatory movement.
In a first step S1, the applicator is inserted into the gap 15 between the door and the fender so that the nozzle 7 is located at the rear of the door.
In a second step S2, the applicator is then placed with the nozzle carrier 2 against the side edge of the door in order to provide mechanical guidance in this spatial direction.
In a step S3, the applicator with the spacer 11 is then placed on the back of the door to ensure mechanical guidance at right angles to the component surface.
In this state, the applicator is then positively guided in two spatial directions.
In a step S4, the applicator is then aligned so that the spray direction is perpendicular or almost perpendicular to the component surface. This offers the advantage that the applied sealant hits the component surface with maximum kinetic energy.
In a step S5, the applicator is then moved along the flanged seam 8 of the door and the sealant is applied to the flanged seam 8 to seal the flanged seam 8.
In a step S6 the applicator is then removed from the gap 15 after coating the flanged seam 8.
In the example shown in
The two hollow cylinders abut against each other with their outer surfaces, whereby the side edges of the flanged body sheet 9 can be held between the two hollow cylinders of the spacer 11.
In the example shown in
In the example shown in
The embodiment in
In the embodiments shown in
In the embodiment shown in
In the embodiment shown in
Two pneumatic cylinders 19, 20 are provided for this purpose, in each of which a piston rod 21, 22 can be displaced, whereby the two piston rods 21, 22 flexibly guide the applicator. The piston rod 21 can be moved in the Y-direction, while the piston rod 22 can be moved in the Z-direction. The two pneumatic cylinders 19, 20 are each subjected to a constant differential pressure via a proportional valve 23, 24, which leads to a corresponding counterforce that is constant regardless of the deflection (immersion depth).
The disclosure is not limited to the preferred embodiments described above. Rather, a large number of variants and modifications are possible which also make use of the inventive idea and therefore fall within the scope of protection. In particular, the disclosure also claims protection for the subject-matter and the characteristics of the dependent claims irrespective of the claims referred to in each case and in particular also without the features of the main claim. The disclosure thus comprises various inventive aspects which can enjoy protection independently of each other.
Number | Date | Country | Kind |
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10 2017 001 780.8 | Feb 2017 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2018/052998 | 2/7/2018 | WO |
Publishing Document | Publishing Date | Country | Kind |
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WO2018/153663 | 8/30/2018 | WO | A |
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