METHOD AND SYSTEM WITH A DEVICE FOR HEATING A CONNECTING ELEMENT

Description

[0001] The invention relates to a system according to the preamble of claim 1. Furthermore, the invention relates to a method for heating a connecting element according to the preamble of claim 9.

[0002] Riveting is a common way to join two parts together. For example, a first part is brought into contact with a second part, or a joining partner, and then firmly connected using a fastener, such as a rivet or pin.

[0003] In thermal riveting of plastic parts, a hot medium, such as hot air, is used to heat the plastic fastener and make it malleable, so that a forming die can deform the fastener to join the two parts. DE 10 2016 006 097 A1 shows in Fig. 1 such a stamp 6 with an inner pressing part 7 and an outer molded part 8. A nozzle ( Fig. 2 ). This nozzle is, for example, tubular in design and dimensioned such that its end portion can be guided at least partially over the connecting element.

[0004] With this process, it is difficult to avoid exposing only the connecting element to heat energy. Thus, in addition to the connecting element, the underlying part, in particular the joining partner, and also the heating device are exposed to thermal energy. This can lead, in particular, to unintentional and, above all, uncontrolled deformation of the joining partner. Furthermore, all components in contact with the parts to be joined are also heated. Sensitive components, such as electrical circuits, in particular, can suffer irreversible damage from high heat. A further disadvantage of the process described above is that a large portion of the thermal energy is dissipated unused into the environment.

[0005] DE 10 2013 000 018 A1 shows a device in which the plunger and nozzle are combined in a single device. This results in a complex device structure.

[0006] Based on this, the object of the invention is to create a system and a method in which the aforementioned disadvantages are eliminated.

[0007] A system for achieving this object has the features of claim 1. Accordingly, it is provided that a preferably at least partially tubular sleeve is arranged around the nozzle and an at least almost annular channel is formed between an outer wall of the nozzle and an inner wall of the sleeve. In this case, the nozzle can in particular be arranged axially in the sleeve. The annular channel has at least largely the same distance between the outer wall of the nozzle and the inner wall of the sleeve. However, it can also be provided that the distance between the outer wall and the inner wall varies. Likewise, it can be provided according to the invention that a cross-section of the nozzle and / or a cross-section of the sleeve deviates from a circular shape, namely is rather oval or has any desired shape.Furthermore, it is provided that the hot medium can be supplied to the connecting element through the nozzle, with an end region of the nozzle at least partially enclosing the connecting element, and that the medium can be discharged from the nozzle through a gap between the end face of the nozzle and a surface of the second part and can be guided away through the channel. This preferably occurs either actively or passively.

[0008] A further development of the present invention can provide that an open end face of the nozzle forming an outlet and an open end face of the sleeve forming an inlet are arranged at a distance above a surface of the second part, wherein a gap is formed between the end faces and the surface of the second part. The distance of the end faces to the surface or the width of the gap can be 0.1 mm, 0.2 mm or 0.5 mm, 1.0 mm, 2.0 mm or 5.0 mm. The distance of the end faces to the surface or the width of the gap can vary depending on the quantity of hot medium to be conveyed through the nozzle.

[0009] Furthermore, an advantageous embodiment of the present invention can provide that an open end face of the nozzle forming an outlet is arranged at a distance above a surface of the second part, wherein a gap is formed between the end face of the nozzle and the surface and an open end face of the sleeve forming an inlet is in contact, in particular in a closing manner, with the surface of the second part, wherein an inner wall of the sleeve forms a closed chamber around the nozzle at least to the surface of the second part. The distance of the end face of the nozzle to the surface or the gap width can assume the same dimension as described in the previous paragraph. Because the end face of the sleeve is in direct contact with the surface of the second part or the joining partner, a closed volume is formed around the nozzle.The hot medium, which is now fed to the connecting element through the nozzle, passes through the gap between the nozzle face and the surface and is discharged through the annular channel. This discharge can occur either passively by discharging the air through the effect of back pressure or actively by suctioning the air away using a pump, particularly a vacuum pump.

[0010] While in the embodiment in which both the end face of the sleeve and the end face of the nozzle are spaced apart from the surface of the second part, a small portion of the hot medium can still leave the device and thus heat energy is lost, in the latter embodiment of the invention the hot medium is returned to the device or nozzle. This prevents the second part or the joining partner or other sensitive components from being undesirably heated, and the unused thermal energy of the heated medium can be reused to heat the connecting element. For example, the extracted air can be fed back into a heating device used to heat the medium. Due to the residual energy in the still warm medium, less energy is required to heat the medium again.

[0011] Preferably, it can also be provided that the end face of the nozzle protrudes from the end face of the sleeve, or that the end face of the sleeve protrudes beyond the end face of the nozzle. This allows, in particular, the application of hot air to the connecting element or the extraction of the hot air to be made more efficient.

[0012] In particular, the sleeve extending in front of the nozzle serves to form a channel or chamber that is closed at least to the surface of the second part. This closed contact of the sleeve with the surface of the second part allows the hot medium to be very efficiently guided away from the second part, thereby minimizing or preventing heating of the second part or other components.

[0013] Furthermore, it can be provided according to the invention that the nozzle and the sleeve are axially movable relative to one another and / or the nozzle is spring-mounted against the sleeve or the sleeve against the nozzle. Because the sleeve is movable relative to the nozzle, for example, the nozzle can first be guided over the connecting element and then the sleeve can be moved axially such that its front side comes into contact with the surface of the second part. In the event that the entire amount of heat cannot be dissipated through the channel, the sleeve could be at least slightly spaced from the surface to allow the hot air to escape. The spring-mounted mounting of the sleeve can compensate for any irregularities or unevenness on the surface of the second part when the front side of the sleeve is placed on this surface.By spring-loading the sleeve or by preloading it with a spring, a largely flush connection between the sleeve and the surface can be achieved, despite any irregularities or unevenness. Any vibrations of the device or the second part can also be compensated for by the spring-loaded sleeve.

[0014] Furthermore, according to the invention, it can be provided that the nozzle and the sleeve form a structural unit and that this unit can be exchanged for another unit comprising a nozzle and a sleeve having an inner diameter corresponding to the size of the connecting element, depending on the size of the connecting element, wherein the unit preferably has a quick-change system. The unit, or set, or assembly, consists of the nozzle and the sleeve and is assigned to the device. Such a quick-change system makes it possible to respond quickly and flexibly to changing requirements or situations. The inner diameter of the nozzle should correspond, at least in the broadest sense, to the dimensions of the connecting element.However, the inner diameter of the nozzle must always be selected so that there is sufficient space between the inner wall of the nozzle and the connecting element to dissipate the hot air.

[0015] Furthermore, according to the invention, at least one sensor means for receiving an identification or label or a barcode of the first and / or second part can be assigned to the nozzle and / or the sleeve. Preferably, the type and quality of the connecting element can also be determined via the at least one sensor means, and the nozzle can be calibrated according to the type and quality of the connecting element. Using this sensor means or the identification of the parts, the entire process of heating the connecting element can be documented and stored. This can be particularly advantageous for quality control.

[0016] One embodiment can provide for a control unit to regulate both the temperature and the volume flow of the hot air. Depending on the size and material of the connecting element as well as the dimensions of the nozzle, different volume flows and temperatures can be advantageous. It is also conceivable for the temperature and volume flow to vary while the connecting element is heating. The aforementioned control unit can also be used to move both the sleeve and the nozzle towards the surface of the second part and then away from it again. It is thus conceivable for the control unit to have image recognition in order to guide the nozzle precisely over the connecting element. Furthermore, the control unit can determine the material of the connecting element directly or indirectly via an identification number. The hot air supply is then adjusted depending on the material.

[0017] A method for achieving the aforementioned object is described by the measures of claim 9. Accordingly, the hot medium is discharged through a channel between a sleeve arranged axially around the nozzle and the nozzle. This discharge prevents the surrounding area, in particular the second part or the joining partner, from becoming excessively heated. Furthermore, the discharge of the hot medium or air can save energy, since the recirculated air can be reused to heat the connecting element.

[0018] Furthermore, it can be provided according to the invention that an open end face of the nozzle forming an outlet and an open end face of the sleeve forming an inlet are positioned at a distance above a surface of the second part, wherein a gap is formed between the end faces and the surface of the second part.

[0019] A further preferred embodiment of the present invention provides that an open end face of the nozzle forming an outlet is positioned at a distance above a surface of the second part, wherein a gap is formed between the end face of the nozzle and the surface and an open end face of the sleeve forming an inlet is brought into contact, in particular in a closing manner, with the surface of the second part, wherein the inner wall of the sleeve forms a closed chamber around the nozzle at least to the surface of the second part.

[0020] Furthermore, a gas flow or the flow of the medium to be heated is initiated before an air heater is started to heat the medium. This ensures that both the connecting element and the nozzle are heated successively. This is particularly gentle on the nozzle and sleeve. Likewise, the medium continues to flow through the nozzle after the air heater has been shut down, allowing the nozzle and connecting element to cool down in a controlled manner and dissipating the remaining heat energy from the device as quickly as possible.

[0021] Preferred embodiments of the invention are explained in more detail below with reference to the drawing, in which: Fig. 1a Bringing a nozzle closer to a connecting element, Fig. 1b Lowering the nozzle over the connecting element to apply hot air, Fig. 1c Moving the nozzle away from the heated connecting element, Fig. 2a A first embodiment for bringing a nozzle with a sleeve closer to a connecting element, Fig. 2b Applying hot air to the connecting element through the nozzle, Fig. 2c Moving the nozzle and the sleeve away after heating the connecting element, Fig. 3a An illustration of a further embodiment for bringing a nozzle with a sleeve closer to a connecting element, Fig. 3b Applying hot air to the connecting element through the nozzle, and Fig. 3c Moving the sleeve and the nozzle away.

[0022] In order to connect a first part 10 with a second part 11, also referred to as joining partner, it is known to first heat a connecting element 12, also referred to as pin or rivet, by applying a hot medium or hot air ( Fig. 1a, 1b, 1c ). In this example, which represents the prior art, the connecting element 12 is an integral component of the first part 10 and is guided through an opening in the second part 11. A nozzle 13, which is essentially tubular in shape, is first guided over the connecting element 12 in the direction of arrow 14 ( Fig. 1a, 1b For clarity, only a portion of the highly schematic nozzle 13 is shown here. It is understood that the connecting element 12 can also be supplied to the nozzle.

[0023] The hot air to be directed through nozzle 13 is generated by a hot air generator (not shown). Air is first fed to the hot air generator and then heated to a specified temperature. A corresponding fan (not shown) accelerates the hot air and directs it through nozzle 13 directly onto the connecting element 12.

[0024] To ensure that the hot air can escape from an end face 15 of the nozzle 13 when heating the connecting element 12 and to prevent the hot air from accumulating, the nozzle 13 is guided over the connecting element 12 just far enough to form a gap 17 between the end face 15 and a surface 16 of the second part 11. The hot air flowing through the nozzle 13 thus heats the connecting element 12 and then leaves the nozzle 13 through the annular gap ( Fig. 1b ).

[0025] After a predetermined time, during which the connecting element 12 has been sufficiently exposed to the hot air, the nozzle 13 is again guided away from the connecting element 12 in the direction of arrow 18 ( Fig. 1c ), or the connecting element 12 is guided away from the nozzle 13. The nozzle 13 is then moved in such a way that it can apply hot air to another connecting element 12, or another first part 10 together with the corresponding second part 11 is aligned relative to the nozzle 13 so that the nozzle can in turn be guided over the connecting element 12. The disadvantage here is that not only the connecting element 12 is heated, but also the surface 16 or the second part 11 or other sensitive components (not shown) that are in contact with the surface. Such heating can lead to irreversible damage. In addition, the Fig. 1a bis 1c In the example shown, a large part of the thermal energy of the medium is lost unused.

[0026] In the case of the Fig. 2a bis 2c The embodiment of the invention shown in the Fig. 1a bis 1c The nozzle 13 shown is supplemented by a sleeve 19. Items of Fig. 2a bis 2c , which are identical to those of the Fig. 1a bis 1c are given the same reference numbers for the sake of clarity.

[0027] Just as before using the Fig. 1a bis 1c As described, in order to heat the connecting element 12, the nozzle 13 is guided over the connecting element 12 in such a way that a gap 17 remains between the surface 16 of the second part 11 and the end face 15 of the nozzle 13. However, it is equally conceivable for the connecting element 12 to be guided into the nozzle 13. The sleeve 19 is now arranged around the nozzle 13 in such a way that a channel 20 is formed between an outer wall of the nozzle 13 and an inner wall of the sleeve 19. This channel 20 can extend in a ring-like manner axially around the nozzle 13 or within the sleeve 19. However, it can also be provided that this channel 20 has any shape and deviates from a ring-like shape.

[0028] An end face 21 of the sleeve 19 is offset slightly backwards in the direction of the arrow 14. As a result, the end face 15 of the nozzle 13 and the end face 21 of the sleeve 19 are offset from each other. Thus, a distance between the end face 21 of the sleeve 19 and the surface 16 of the second part 11 is greater than a distance between the end face 15 of the nozzle 13 and the surface 16 of the second part 11 ( Fig. 2b ).

[0029] If the connecting element 12 is now subjected to hot air, the still hot air emerging from the end face 15 of the nozzle 13 can be sucked away through the channel 20 between the nozzle 13 and the sleeve 19. This suction can be carried out actively by a vacuum pump (not shown), which is connected to the sleeve 19, for example, on a side opposite the end face 21. It is also conceivable for the hot air to be passively discharged through the channel 20 due to the effect of the dynamic pressure. Through this active or passive discharge of the hot air, at least a large part of the hot air emerging from the nozzle 13 can be guided away from the surface 16 and fed back to the hot air generator and the fan for reheating the connecting element 12.

[0030] As soon as the connecting element 12 has been sufficiently exposed to hot air, the unit consisting of sleeve 19 and nozzle 13 is moved away from the connecting element 12 in the direction of arrow 18 ( Fig. 2c ).

[0031] In the Fig. 3a bis 3c The embodiment of the invention shown in the drawings is significantly different from that shown in the Fig. 2a bis 2c illustrated embodiment in that during the application of hot air to the connecting element 12 the end face 21 of the sleeve 19 is brought into contact with the surface 16 of the second part 11 ( Fig. 3b ). Otherwise, the situation is the same in the Fig. 3a bis 3c The embodiment shown is similar to that shown in the Fig. 2a bis 2c illustrated embodiment, which is why the same reference numerals are used for the same objects.

[0032] Because the sleeve 19 rests with its front side 21 on the surface 16 of the second part 11, all the hot air that passes through the front side 15 of the nozzle 13 into the channel 20 is sucked away ( Fig. 3b ). In this way, all of the hot air can be reused to heat the connecting element 12. Furthermore, by forming a closed chamber around the nozzle 13, the connecting element 12 can be heated without exposing the surrounding parts, in particular the second part 11 or sensitive components, to excessive heat.

[0033] In the Fig. 3a bis 3c In the illustrated embodiment, it can be provided that the end face 21 of the sleeve 19 is offset in the direction of arrow 14 from the end face 15 of the nozzle 13. Due to this offset, a gap 17 forms between the end face 15 of the nozzle 13 and the surface 16, while the end face 21 of the sleeve 19 can be deposited on the surface 16.

[0034] Furthermore, it can be provided that the sleeve 19 and the nozzle 13 are axially movable relative to each other. Due to the possibility of moving the nozzle 13 and the sleeve 19 relative to each other, both the embodiment of the Fig. 2a bis 2c and the embodiment of the Fig. 3a bis 3ccan be realized. Due to any spring preload between the sleeve 19 and the nozzle 13, these move back to an initial position as soon as a force triggering the relative movement is switched off. Due to the spring preload or a spring-loaded mounting of the sleeve 19 or the nozzle 13, any irregularities or unevenness on the surface 16 of the second part 11 can be compensated for when the end face 21 of the sleeve 11 is placed on the surface 16. Due to the spring-loaded mounting of the sleeve 19 or due to a spring preload of the sleeve 19, a connection between the sleeve 19 and the surface 16 that is at least largely flush can be achieved despite any irregularities or unevenness. Any vibrations of the device or the second part 11 can also be compensated for by the spring-loaded mounting of the sleeve 19.The relative movement can be effected, for example, by a drive (not shown), which is operated by a control unit (also not shown) such that when the unit consisting of the nozzle 13 and the sleeve 19 is lowered, the sleeve 19 is guided over the nozzle 13. This control unit can also be used to check whether the sleeve 19 or the nozzle 13 has been moved back to its original position after the connecting element 12 has been subjected to hot air. List of reference symbols

[0035] 10First part 11Second part 12Connecting element 13Nozzle 14Arrow direction 15End face 16Surface 17Gap 18Arrow direction 19Sleeve 20Channel 21End face

Claims

1. System having a device for heating a connecting element (12), in particular a pin or a rivet, and having a first part (10) and having a second part (11); wherein the device has a nozzle (13); and wherein the connecting element (12) is able to be impinged with a hot medium, preferably hot air, by the nozzle (13); and wherein the connecting element (12) is assigned to the first part (10) and serves for connecting the first part (10) to the second part (11), in particular a mating part; and wherein a tubular sleeve (19) is disposed about the nozzle (13), and an at least almost annular duct (20) is formed between an external wall of the nozzle (13) and an internal wall of the sleeve (19); and wherein the hot medium is able to be supplied to the connecting element (12) through the nozzle (13); and wherein the medium is able to be discharged from the nozzle (13) through a gap (17) between an end side (15) of the nozzle (13) and a surface (16) of the second part (11), and is able to be conveyed away, preferably able to be actively or passively suctioned, through the duct (20), characterized in that an end region of the nozzle (13) at least partially encloses the connecting element (12).

2. System according to Claim 1, characterized in that an open end side (15) of the nozzle (13), which open end side forms an outlet, and an open end side (21) of the sleeve (19), which open end side forms an inlet, are disposed at a spacing above a surface (16) of the second part (11), wherein a gap (17) is in each case formed between the end sides (15, 21) and the surface (16) of the second part (11).

3. System according to Claim 1, characterized in that an open end side (15) of the nozzle (13), which open end side forms an outlet, is disposed at a spacing above a surface (16) of the second part (11), wherein a gap (17) is formed between the end side (15) of the nozzle (13) and the surface (16), and an open end side (21) of the sleeve (19), which open end side forms an inlet, is in contact, in particular closing contact, with the surface (16) of the second part (11), wherein an internal wall of the sleeve (19) forms a closed chamber about the nozzle (13) at least in relation to the surface (16) of the second part (11).

4. System according to one of the preceding claims, characterized in that the end side (15) of the nozzle (13) protrudes from the end side (21) of the sleeve (19), or in that the end side (21) of the sleeve (19) protrudes beyond the end side (15) of the nozzle (13).

5. System according to one of the preceding claims, characterized in that the nozzle (13) and the sleeve (19) are displaceable axially relative to one another, and / or the nozzle (13) is mounted resiliently in relation to the sleeve (19).

6. System according to one of the preceding claims, characterized in that the nozzle (13) and the sleeve (19) form a structural unit and this unit, as a function of a size of the connecting element (12), is interchangeable with another unit having a nozzle (13) and a sleeve (19) which have internal diameters corresponding to the size of the connecting element (12), wherein the unit preferably has a quick-release attachment system.

7. System according to one of the preceding claims, characterized in that the nozzle (13) and / or the sleeve (19) are / is assigned at least one sensor means for recording an identification or labelling of the first and / or of the second part (11), wherein the type and the configuration of the connecting element (12) are preferably also able to be established by way of the at least one sensor means.

8. System according to one of the preceding claims, characterized in that the heated connecting element (12) is able to be deformed by a form punch in a further device for riveting the parts (10, 11), wherein the device for heating is in spatial terms separated from the device for riveting.

9. Method for contactlessly heating a connecting element (12), in particular a pin or a rivet, by a tubular nozzle (13), wherein the connecting element (12) is impinged with a hot medium, preferably hot air; and wherein the connecting element (12) is assigned to a first part (10) and serves for connecting the first part (10) to a second part (11), in particular a mating part; and wherein the hot medium is supplied to the connecting element (12) through the nozzle (13); and wherein the medium is discharged from the nozzle (13) through a gap (17) between an end side (15) of the nozzle (13) and a surface (16) of the second part (11), and is discharged, preferably actively or passively suctioned, through a duct (20) between a sleeve (19) disposed axially about the nozzle (13) and the nozzle (13), characterized in that, while the hot medium is being supplied to the connecting element (12) through the nozzle (13), an end region of the nozzle (13) is disposed so as to at least partially enclose the connecting element (12).

10. Method according to Claim 9, characterized in that an open end side (15) of the nozzle (13), which open end side forms an outlet, and an open end side (21) of the sleeve (19), which open end side forms an inlet, are positioned at a spacing above a surface (16) of the second part (11), wherein a gap is in each case formed between the end sides (15, 17) and the surface (16) of the second part (11).

11. Method according to Claim 9, characterized in that an open end side (15) of the nozzle (13), which open end side forms an outlet, is positioned at a spacing above a surface (15) of the second part (11), wherein a gap (17) is formed between the end side (15) of the nozzle (13) and the surface (16), and an open end side (21) of the sleeve (19), which open end side forms an inlet, is brought into contact, in particular closing contact, with the surface (15) of the second part (11), wherein the internal wall of the sleeve (19) forms a closed chamber about the nozzle (13) at least in relation to the surface (15) of the second part (11).

12. Method according to one of Claims 9 to 11, characterized in that the heated connecting element (12) is deformed by a form punch in a further device for riveting the parts (10, 11), wherein the connecting element (12) is transported to the device for riveting, or the device for riveting is supplied to the connecting element (12).