Joining apparatus for connecting a joining partner to a support using a fastening means

Abstract

The invention relates to a joining apparatus for connecting a joining partner (2) to a support (3) using a fastening means (4) having a geometric fastening means axis (A), wherein the joining apparatus (1) has a joining device (5) for connecting the joining partner (2) to the support (3) using the fastening means (4), wherein, in the mounted state, the fastening means (4) has a shank portion (6), which extends along the geometric fastening means axis (A) and which at least partially extends through the joining partner (2) and the support (3), and a head portion (7), which adjoins the shank portion (6) and has a bearing surface (8) which, according to a desired mounting state, is in direct and / or indirect engagement with a counterpart bearing surface (9) of the support (3), wherein the joining apparatus (1) has a measuring and checking device (13) for detecting the direct and / or indirect engagement of the bearing surface (8) with the counterpart bearing surface (9). It is proposed that the measuring and checking device (13) is designed to measure the temperature and / or the change of temperature of the joining partner (2) and / or of the fastening means (4) within a checking region (14) adjoining the bearing surface (8) and / or the counterpart bearing surface (9) and, on the basis thereof, to detect the direct and / or indirect engagement of the bearing surface (8) with the counterpart bearing surface (9).

Description

[0001] Joining device for connecting a joining partner to a carrier using a fastening device

[0002] The present invention relates to a joining device for connecting a joining partner to a carrier by means of a fastening means according to the preamble of claim 1 and to a joining method for connecting a joining partner to a carrier by means of a fastening means according to the preamble of claim 14.

[0003] The known prior art (US 2017 / 0089727 A1), from which the invention is based, discloses a joining device for connecting a joining partner to a carrier using a fastening means which is designed as a screw with a shaft section and a head section, in this case the screw head. During the joining process, it is intended to ensure that a desired assembly state is achieved in which the head section engages with the joining partner, i.e. a contact surface of the head section is in direct and / or indirect engagement with a counter-contact surface of the joining partner. To check whether the screw is tightened according to the desired assembly state, at least one permanent magnet is placed on the head section, which rotates with the head section when screwed in. A Hall sensor placed next to the screw detects the rotations performed by the screw when the screw is screwed in.The number of rotations completed is used to determine whether the support surface is in engagement with the counter support surface or not.

[0004] It is also known to measure the distance between the head section, for example, the upper face of the head section, and a reference point. If a specified distance is reached during screwing, it can be concluded that the head section is engaged with the joining partner according to the desired assembly state.

[0005] A challenge with both approaches is that manufacturing-related shape deviations of the screw, the carrier, and / or the joining partner can lead to an incorrect determination of whether the bearing surface is in engagement with the counter-bearing surface or not. If the external thread of the screw, the internal thread of the joining partner, and / or the carrier exhibit tolerance-related deviations, this can result in the bearing surface not engaging with the counter-bearing surface, even though the specified number of turns has been achieved during screwing. If, for example, the head section exhibits deviations along the geometric screw axis, the bearing surface cannot engage with the counter-bearing surface, even though the specified distance between the head section and the reference point is present.

[0006] The invention is based on the problem of designing and developing the known joining device in such a way that the determination of whether the support surface is in engagement with the counter support surface in accordance with the desired assembly state is carried out in a particularly reliable manner.

[0007] The above problem is solved by the features of the characterising part of claim 1.

[0008] The fundamental consideration is that the correct joining between the joining partner and the carrier using the fastener can be detected based on the temperature and / or temperature change of the carrier and / or the fastener in a test area during and / or after the joining process. Interestingly, it has been discovered that during a corresponding joining process, the carrier and / or the fastener heats up more in an area surrounding the counter-supporting surface and / or the support surface when the support surface comes into direct and / or indirect engagement with the counter-supporting surface.

[0009] During the joining process, contact between the head section and the joining partner results in friction effects between the head section and the joining partner, causing the head section and the joining partner to heat up in the area of ​​the support surface and the counter-support surface. The test area adjacent to the support surface and / or the counter-support surface is heated by heat conduction. The resulting temperature increase of the joining partner in the test area therefore only occurs when the head section comes into contact with the joining partner. In this way, the engagement of the support surface with the counter-support surface can be determined particularly reliably based on the measured temperature and / or temperature change, corresponding to a desired assembly condition.

[0010] In particular, it is proposed that the measuring and testing device is designed to measure the temperature and / or the temperature change of the joining partner and / or the fastening means within a test area adjacent to the support surface and / or the counter support surface and to detect the indirect and / or direct engagement of the support surface with the counter support surface on the basis of the measured temperature and / or temperature change.

[0011] According to the embodiment according to claim 2, the fastening means is designed as a screw or has a screw, whereby the engagement between the support surface and the counter-support surface according to the desired assembly state can be detected in a particularly effective manner on the basis of the measured temperature and / or temperature change.

[0012] According to claim 3, a quantitative, reproducible determination of whether the support surface engages with the counter-support surface is enabled by the measuring and testing device, which is designed to form a characteristic value from the measurement of the measuring and testing device and relate it to a defined threshold characteristic value. The threshold characteristic value can advantageously correspond to a temperature value, a temperature change, or a temperature change relative to a unit of time (claim 4).

[0013] According to claim 5, monitoring the joining process is particularly simplified if the temperature and / or temperature change is measured without contact. The measurement can be carried out using a thermal imaging camera and / or at least one pyroelectric sensor.

[0014] According to the further embodiment according to claim 6, the measuring and testing device can be designed for continuous measurement of the temperature and / or temperature change, so that a temperature and / or a temperature change of the joining partner and / or the fastening means can advantageously be detected at any time. In an alternative and particularly preferred embodiment, the measuring process is initiated by a start signal, thereby achieving particularly efficient use of the measuring and testing device.

[0015] According to claim 7, the measuring and testing device comprises an evaluation unit, which, in particular, allows images from a thermal imaging camera to be evaluated particularly efficiently. A corresponding evaluation unit can detect and distinguish objects, allowing the evaluation to be limited to sub-areas of the area captured by the thermal imaging camera in a particularly resource-efficient manner.

[0016] According to the embodiment according to claim 8, the measuring and testing device has or is connected to a documentation unit. The documentation unit assigns a quality criterion to each joining partner that has been connected to a carrier using a fastening device, depending on the measured temperature and / or temperature change. It can then be traced to each joining component produced during a joining process whether the engagement of the support surface with the counter-support surface has occurred in accordance with the desired assembly state.

[0017] According to the preferred embodiment according to claim 9, the joining device comprises or is connected to a control and regulation unit. The control and regulation unit can change at least one joining parameter of the joining process depending on the measured temperature and / or temperature change, thereby enabling automatic process control. This control can reduce scrap and improve process quality.

[0018] According to the further embodiment according to claim 10, the joining device comprises a hold-down device that holds the joining partner and the carrier in a desired joining position to enable reliable connection of the two aforementioned components using the fastening means. Alternatively or additionally, the desired joining position of the joining partner and the carrier can be detected using position detection. Claim 11 relates to particularly advantageous embodiments of the joining partner, the carrier, and the fastening means made of plastic and / or metal.

[0019] In order to prevent the influence of external sources of interference on the measurement of the temperature and / or the temperature change, the joining device according to claim 12 has a shield which encloses the joining area at least in sections.

[0020] According to the further embodiment according to claim 13, the joining partner and / or the fastening means has a coating at least in sections within the test area, by means of which the reflection, the absorption and / or the transmission of the joining partner and / or the fastening means is changed.

[0021] According to a further teaching according to claim 14, which has independent significance, a joining method is claimed for connecting a joining partner to a carrier by means of a fastening means with a geometric fastening means axis, in particular with a joining device according to the proposal, wherein in the mounted state of the joining partner on the carrier, the fastening means has a shaft section extending along the geometric fastening means axis, which extends at least partially through the joining partner and the carrier, and a head section adjoining the shaft section with a bearing surface which is in direct and / or indirect engagement with a counter-bearing surface of the carrier, wherein the joining partner is connected to the carrier by means of a fastening means,whereby the indirect and / or direct engagement of the support surface with the counter support surface is determined by means of a measuring and testing device.

[0022] It is essential that the temperature and / or temperature change of the joining partner and / or the fastener is measured in a test area adjacent to the support surface and / or counter-support surface, and that the measured temperature and / or temperature change is used to detect the indirect and / or direct contact of the support surface with the counter-support surface. Reference may be made to all statements regarding the proposed joining device in this regard.

[0023] According to claim 15, a quantitative, reproducible determination that the support surface is in indirect and / or direct engagement with the counter-support surface is made possible by forming a characteristic value from the measured temperature and / or temperature change and relating it to a defined limit threshold characteristic value.

[0024] According to the embodiment according to claim 16, each joining process, and thus each joining component produced thereby, is assigned a quality criterion depending on the measured temperature and / or temperature change. It can then be traced for each joining process whether the contact surface has been contacted with the counter-contact surface.

[0025] According to the particularly preferred embodiment according to claim 17, at least one joining parameter of the joining process is changed depending on the measured temperature and / or temperature change, thereby enabling automatic process control. This control can reduce scrap and improve process quality.

[0026] In the following, the invention is explained in more detail with reference to a drawing which merely illustrates exemplary embodiments. In the drawing,

[0027] Fig. 1 shows a proposed joining device for connecting a joining partner to a carrier using a fastening means with a detailed view of an area covered by a measuring and testing device of the joining device,

[0028] Fig. 2 shows a cross-sectional view of the joining partner and the carrier, which are connected to one another by means of the fastening means, in a) a desired assembly state, b) a state not corresponding to the desired assembly state, c) a desired assembly state when using a fastening aid and d) a state not corresponding to the desired assembly state when using a fastening aid and Fig.3 schematically a diagram in which a) the torque and the speed are plotted over time with which the joining partner is connected to the carrier by means of a fastening means designed as a screw, b) the temperature of the joining partner and / or the fastening means in the test area is plotted over time during and after a joining process in which the target assembly state is achieved, and c) the temperature of the joining partner and / or the fastening means in the test area is plotted over time during and after a joining process in which the target assembly state is not achieved.

[0029] Fig. 1 shows a joining device 1 with which a joining partner 2 can be fastened to a carrier 3 and / or connected thereto. The joining partner 2 is connected to the carrier 3 via a fastening means 4. The fastening means 4 has a geometric fastening axis A, as shown in Fig. 2. The joining device 1 also has a joining device 5 for connecting the joining partner 2 to the carrier 3 using the fastening means 4.

[0030] The joining partner 2 can be, for example, a vehicle instrument panel, and the carrier 3 can be an instrument panel. Alternatively, the joining partner 2 can also be designed as a circuit board and / or printed circuit board, and the carrier 3 can be designed as a circuit board and / or printed circuit board carrier. It is also conceivable to electrically connect the circuit board and / or printed circuit board to the carrier 3 via the fastening means 4.

[0031] The joining device 1 can be manually operated, and in particular manually portable, or, in an alternative and thus preferred embodiment, can be operated automatically, and in particular stationary, as part of a series production. The illustrated and thus preferred embodiment is a stationary joining device 1 as part of a series production. All relevant statements apply accordingly to all other types of joining devices 1. When the joining partner 2 is mounted on the carrier 3, these are connected to one another directly and / or indirectly via the fastening means 4, as shown in Fig. 2a).The term "assembled state" is understood here to mean that the joining partner 2 is arranged on the carrier 3, in particular touching it, and is fixed thereto via the fastening means 4, in particular in a form-fitting and / or force-fitting manner in the axial and / or radial direction relative to the geometric fastening means axis A. The fastening means 4 has a shaft section 6 extending along the geometric fastening means axis A, which extends at least partially through the joining partner 2 into the carrier 3. As can be seen from Fig. 2a), the fastening means 4 here and preferably penetrates the joining partner 2 completely and the carrier 3 in sections. It is also conceivable for the fastening means to completely penetrate the joining partner 2 and the carrier 3 in the assembled state.

[0032] The fastening means 4 has, at least in the mounted state of the joining partner 2 on the carrier 3, a head section 7 adjoining the shaft section 6. The head section 7 has a bearing surface 8, which, during the joining process, comes into direct and / or indirect engagement with a counter bearing surface 9 of the joining partner 2 according to a desired assembly state. The term "directly engaged" is to be understood here as meaning that the head section 7, in the mounted state, bears directly against the joining partner 2, so that the bearing surface 8 bears against the counter bearing surface 9. The direct engagement between the bearing surface 8 and the counter bearing surface

[0033] 9 is shown in Fig. 2a).

[0034] It is also conceivable that the fastening means 4 is a fastening aid

[0035] 10, which in the assembled state is arranged between the head section 7 and the joining partner 2, as shown in Fig. 2c). The support surface 8 and the counter-support surface 9 then each bear against the fastening aid 10. The term "indirectly engaged" is to be understood here as meaning that the head section 7 in the assembled state bears against the joining partner 2 via a fastening aid 10 (Fig. 2c)). Here and preferably, the fastening aid 10 is annular. The head section 7 here and preferably in the region of the support surface 8 has a round outer contour 11. The outer contour 11 of the head section 7 can also have a different shape, for example a hexagon.As shown in the figures, in the case of direct engagement, the counter-supporting surface 9 results from the geometry of the support surface 8 and thus from the shape of the head section 7, more precisely from the outer contour 11 of the head section 7. In the case of indirect engagement between the support surface 8 and the counter-supporting surface 9, the counter-supporting surface 9 results from the geometry, in particular the radial edge contour 12, of the fastening aid 10.

[0036] In order to detect whether the support surface 8 is in engagement with the counter support surface 9, the joining device 1 has a measuring and testing device 13. The measuring and testing device 13 is designed to detect the indirect and / or direct engagement between the support surface 8 and the counter support surface 9 according to the desired assembly state (Fig. 2a) and Fig. 2c)).

[0037] It is now essential that the measuring and testing device 13 is designed to measure the temperature and / or the temperature change of the joining partner 2 and / or the fastening means 4 within a test area 14 adjacent to the counter support surface 9 and / or the support surface 8 and to detect the indirect and / or direct engagement of the support surface 8 with the counter support surface 9 on the basis of the measured temperature and / or temperature change.

[0038] During the joining process, engagement occurs between the shaft section 6 and the joining partner 2 and / or the carrier 3, creating friction between the engaged components, which leads to heating of the respective components. Through thermal conduction, the joining partner 2 can heat up in the test area 14, even if the support surface 8 does not engage the counter support surface 9 and thus a state corresponding to the desired assembly state is not achieved, as shown in Fig. 2b), Fig. 2d), and Fig. 3c).

[0039] However, if the head section 7 of the fastening means 4 comes into direct and / or indirect engagement with the joining partner 2, thereby achieving the desired assembly state, frictional effects occur between the head section 7 and the joining partner 2, causing the head section 7 and the joining partner 2 to heat up additionally in the area of ​​the support surface 8 and the counter-support surface 9. Due to thermal conduction, the test area 14 adjacent to the counter-support surface 9 and / or the support surface 8 is heated to a greater extent, as shown in Fig. 2a), Fig. 2c) and Fig. 3b), than if the support surface 8 does not engage with the counter-support surface 9.

[0040] This effect is further enhanced by the fact that heat generated during the joining process and absorbed by the shaft section 6 can be transferred to the joining partner 2 in the area of ​​the contact surface 8 and the counter-contact surface 9 by thermal conduction when the head section 7 engages with the joining partner 2. As a result, the joining partner 2 heats up additionally in the area of ​​the counter-contact surface 9, which also causes the test area 14 to heat up additionally.

[0041] Thus, upon reaching the desired assembly state, a significantly higher temperature increase of the joining partner 2 and / or the fastening element 4 in the test area 14 occurs, as shown in Fig. 3b), than in a joining process in which the support surface 8 does not engage with the counter-support surface 9, as shown in Fig. 3c). In this way, the engagement of the support surface 8 with the counter-support surface 9 can be determined particularly reliably based on the measured temperature and / or temperature change.

[0042] The friction generated during joining, and the resulting heat, depends on the joining speed, the joining force, and the friction pairing between the joining partner 2 and the fastener 4. The term "friction pairing" refers to all factors influencing the friction behavior between the joining partner 2 and the fastener 4. Examples include the material pairing and surface roughness.

[0043] Interestingly, it has also been discovered that the measured temperature and / or temperature change not only reveals the indirect and / or direct engagement of the support surface 8 with the counter-support surface 9. Rather, it is also possible to use the measured temperature and / or temperature change to additionally detect whether the fastening means 4 has connected the joining partner 2 to the carrier 3 with a predetermined target parameter, in particular with a target joining force and / or with a target joining torque. A connection produced with insufficient joining forces and / or joining torques can thus be detected despite indirect and / or direct engagement of the support surface 8 with the counter-support surface 9, thereby increasing the security of the connection between the joining partner 2 and the carrier 3.

[0044] As already explained above, the test area 14 directly adjoins the support surface 8 and / or the counter support surface 9 in the assembled state. The test area 14 extends here and preferably in the radial direction around the counter support surface 9 and is designed in particular as an annular surface enclosing the counter support surface 9. It is particularly advantageous if the test area 14 has a radially outer contour 16 corresponding to the outer contour 15 of the counter support surface 9. The distance between the radially outer contour 16 of the test area 14 and the outer contour 15 of the counter support surface 9 is then identical at every position of the radially outer contour 16. Alternatively or additionally, the test area 14 can directly adjoin the support surface 8 and be formed in the region of a radial outer surface 17 of the head section 7.

[0045] If, as shown in Fig. 2c), a fastening aid 10 is used, the test area 14 can additionally extend beyond the fastening aid 10. Thus, the test area 14 can extend around the support surface 8 on the end face 18 of the fastening aid 10 facing the head section 7. Additionally, the test area 14 can also be formed in the area of ​​the outer contour 11 of the fastening aid 10, as shown in Fig. 2c).

[0046] Here and preferably, the distance between the radially outer contour 16 of the test area 14 and the outer contour 15 of the counter support surface 9 is between 0.5 mm and 10 mm, preferably between 0.5 mm and 7.5 mm, more preferably between 0.5 mm and 5 mm.

[0047] Here and preferably, the distance between an axial outer contour 19 of the test area 14 and the support surface 8 is between 0.5 mm and 10 mm, preferably between 0.5 mm and 7.5 mm, more preferably between 0.5 mm and 5 mm.

[0048] It is conceivable to measure the temperature and / or temperature change at one or more positions in the test area 14. The measured temperatures and / or temperature changes can then be considered individually or mathematically averaged.

[0049] In the following, the term "engagement" is used to describe an indirect and / or direct engagement of the support surface 8 with the counter-support surface 9. Only when the distinction between an indirect and a direct engagement is crucial is the term "indirect engagement" or "direct engagement" explicitly used.

[0050] In the preferred embodiment shown in the figures, the fastening means 4 is designed as a screw and / or comprises a screw. The said head section 7 in this case is the screw head. In principle, according to an embodiment not shown here, a threaded nut can also form the head section. When using a fastening aid 10, this can be designed, in particular, as a washer.

[0051] Here, and preferably, the fastening means 4 is a thread-forming or self-tapping screw. This allows for particularly simple joining, since prior threading of the support 3 and, if applicable, the joining partner 2 is not necessary.

[0052] However, it is also conceivable for the fastening means 4 to be a threaded screw that is screwed into a cut thread of the joining partner 2 and optionally of the carrier 3. In a further alternative and, in this respect, preferred embodiment, the fastening means 4 comprises a screw that, when screwed to a nut, connects the joining partner 2 to the carrier 3. In the following, the joining will be described using a fastening means 4 designed as a screw, although this is to be understood merely as an example and not as exhaustive. The screw can be any type of screw with a head portion 7, in particular also a countersunk head screw.

[0053] As already explained above, friction during joining is influenced by several factors. With regard to a screw as the fastening element 4, these include, for example, the joining speed, i.e., the rotational speed n of the screw during the joining process, the thread pitch, the torque M with which the screw is tightened, and the friction pairing between the joining partner 2 and the fastening element 4.

[0054] Furthermore, it is preferably provided here that the measuring and testing device 13 is designed to generate a characteristic value from the measured temperature and / or temperature change and to detect the indirect and / or direct engagement of the support surface 8 with the counter-support surface 9 by exceeding a threshold characteristic value. The term "characteristic value" is understood here to mean a measurement value that serves for quantification and is based on a specification for the quantitative, reproducible measurement of a quantity, condition, or process. The characteristic value is thus compared with a predetermined, defined threshold characteristic value.

[0055] If the temperature and / or the temperature change are measured at multiple positions in the test area 14, a characteristic value can be calculated for each measured position, and exceeding the threshold characteristic value at one position represents confirmation that the connection is in the desired assembly state. Alternatively, it is also conceivable that only exceeding the threshold characteristic value at all measured positions represents confirmation that the connection is in the desired assembly state. The measurement results can also be averaged, so that, for example, exceeding the threshold characteristic value confirms the connection is in the desired assembly state using a characteristic value averaged from the measurement results.

[0056] Determining whether the connection is in the desired assembly state can be achieved particularly reliably if the temperature and / or temperature change is measured at multiple positions in the test area 14. It is then possible to detect, based on different temperatures and / or temperature changes at different positions, that the support surface 8 is in uneven, direct and / or indirect engagement with the counter-support surface 9, thereby reliably detecting a further condition deviating from the desired assembly state.

[0057] Here, and preferably, the measuring and testing device 13 is designed to generate a quality signal depending on the characteristic value. The quality signal can be an optical, acoustic, electrical, and / or electronic signal. For example, a visual display device can be provided to indicate whether or not the threshold characteristic value has been exceeded. Alternatively or additionally, an acoustic indication can be provided to indicate whether or not the threshold characteristic value has been exceeded.

[0058] Detecting the presence of a connection between the joining partner 2 and the carrier 3 corresponding to the desired assembly state can be done particularly easily if the threshold characteristic corresponds to a temperature value. Exceeding a certain temperature of the carrier 3 and / or the fastening element 4 in the test area 14 then shows that the connection corresponds to the desired assembly state. It should be noted that the measured temperature within the test area 14 depends on the ambient temperature and the temperature of the joining partner 2, the fastening element 4, and the carrier 3 at the beginning of the joining process. Thus, a temperature value is suitable as a threshold characteristic particularly if the ambient temperature and the temperature of the joining partner 2, the fastening element 4, and the carrier 3 at the beginning of the joining process are known.

[0059] Alternatively or additionally, it is conceivable for the limit threshold characteristic value to correspond to a temperature change of the carrier 3 and / or the fastening means 4 in the test area 14. In this way, the desired assembly state can be determined independently of the absolute temperature of the carrier 3 and / or the fastening means 4 in the test area 14. It is then not absolutely necessary to know the temperature of the joining partner 2, the fastening means 4, and the carrier 3 at the beginning of the joining process, which simplifies the determination of the desired assembly state. The limit threshold characteristic value can be 0.3 K to 10 K, preferably 0.4 K to 5 K, more preferably 0.5 K to 3 K.

[0060] In the embodiment shown in the figures and thus preferred, it is alternatively or additionally provided that the limit threshold characteristic value corresponds to a temperature change within a predetermined time. The presence of a connection according to the desired assembly state between the joining partner 2 and the carrier 3 can then be detected in a particularly reliable manner, regardless of the ambient temperature and the temperature of the joining partner 2, the fastening means 4, and the carrier 3. Here and preferably, the limit threshold characteristic value is 0.5 K / s to 25 K / s, preferably 0.75 K / s to 15 K / s, more preferably 1 K / s to 5 K / s.

[0061] In Fig. 3a), the connection of the joining partner 2 to the carrier 3 by means of the fastening means 4 designed as a screw and, if appropriate, using the fastening aid 10 designed as a washer as a component of the fastening aid 4 is shown schematically by the torque M plotted over time and the speed n with which the joining partner 2 is screwed to the carrier 3. While the speed n remains constant at the beginning of screwing in the screw, the torque M initially increases slightly and then increasingly. The speed n becomes zero when the support surface 8 of the head section 7 in the desired assembly state engages the counter support surface 9 of the carrier 3 at time t0, or when further tightening at time t0 requires a higher torque M. At the same time, the torque M reaches its maximum.

[0062] Fig. 3b) shows, by way of example, the temperature of the joining partner 2 in the test area 14 over time during and after a joining process during which the desired assembly state is achieved. As can be seen from Fig. 3b), the temperature of the joining partner 2 in the test area 14 only rises slightly to the temperature To during the joining process up to time t0. From time t0, the temperature of the joining partner 2 in the test area 14 rises significantly more sharply and exceeds the temperature To+ATmin before time t0+At. A qualitatively identical temperature profile over time is achieved when measuring the temperature of the fastening element 4 in the test area 14. Fig.3c) shows, by way of example, the temperature of the joining partner 2 in the test area 14 over time during and after a joining process in which the target assembly state is not achieved, for example because the fastening means 4 designed as a screw gets caught and / or tilted in the carrier 3 or because further penetration of the fastening means 4 into the carrier 3 and / or the joining partner 2 is prevented, for example due to contamination. As can be seen from Fig. 3c), the temperature of the joining partner 2 in the test area 14 only rises slightly to the temperature To during joining up to time t0. The temperature behavior during joining is essentially independent of whether the target assembly state is achieved or not. From time t0 onwards, the temperature of the joining partner 2 in the test area 14 may rise somewhat more sharply.However, the temperature does not reach or exceed the temperature To+ATmin until a specified time t0+At. A qualitatively identical temperature profile over time is achieved by measuring the temperature of the fastener 4 in the test area 14.

[0063] As is clear from the combined analysis of Fig. 3b) and Fig. 3c), a correspondingly strong temperature increase of the joining partner 2 and / or the fastening element 4 in the test area 14 following the joining process only occurs when the desired assembly state has been reached. Therefore, the limit threshold characteristic value is preferably designed as a temperature value To+ATmin, as a temperature change AT, or as a temperature change over a specified time ATmin / At.

[0064] The temperature and / or the temperature change of the carrier 3 and / or the fastening means 4 in the test area 14 can be measured in a particularly simple manner if the measuring and testing device 13 is designed for contactless measurement of the temperature and / or the temperature change, as shown in Fig. 1. Here and preferably, the measuring and testing device 13 has at least one optical sensor for contactless measurement of the temperature and / or the temperature change. The optical sensor can advantageously be a thermal imaging camera or multiple imaging cameras and / or one or more pyroelectric sensors. Thermal imaging cameras and pyroelectric sensors are cost-effective and reliable. It is conceivable that the measuring and testing device 13 is designed for continuous measurement of the temperature and / or the temperature change of the joining partner 2 and / or the fastening means 4 in the test area 14.If the limit threshold characteristic value is exceeded, a plausibility check can be carried out if necessary to determine whether the exceeding of the limit threshold characteristic value was preceded by a joining of the joining partner 2 with the carrier 3 or whether this occurred with a corresponding temporal overlap.

[0065] In an alternative and, in this respect, preferred embodiment, the measuring and testing device 13 is designed to begin a measuring process as a function of a start signal, here and preferably as a function of a start signal generated by the joining device 5. For this purpose, the measuring and testing device 13 is signal-connected to the joining device 5. Upon receipt of the start signal, the measurement of the measuring and testing device 13 is started. By starting the measurement sequentially, the aforementioned plausibility check can be omitted. Furthermore, erroneous measurements that are not related to a joining process are avoided. Furthermore, the measuring and testing device 13 can be used more efficiently if a measurement is only performed when a joining process is also being carried out.

[0066] Here, and preferably, the start signal is generated when a threshold value of a joining parameter is exceeded, undershot, and / or reached when joining the joining partner 2 to the carrier 3. The term "joining parameter" is understood here to mean all framework conditions influencing the joining process, for example, the force acting between the support surface 8 and the counter-support surface 9 in the assembled state (joining force), the torque M acting on the fastening element 4, in particular the head section 7, and / or the joining partner 2, and / or the rotational speed n of the fastening element 4, in particular the head section 7, in particular absolute or relative to the joining partner 2. It is therefore particularly advantageous if the threshold value corresponds to a force, a torque M, and / or a rotational speed n. For example, the start signal can be generated when a predetermined torque M with which the screw is tightened is exceeded and / or reached.Alternatively or additionally, the speed of the screw, for example, falling below and / or reaching a specified speed n can also trigger the generation of the start signal. Other or additional ways of generating the start signal are also conceivable.

[0067] It is particularly advantageous if the measurement of the measuring and testing device

[0068] 13 is started as soon as the joining process is completed, in Fig. 3 at time t0. Since the heat conduction from the counter support surface 9 into the test area

[0069] 14 requires a certain amount of time, it is sufficient if the measurement is started immediately after the joining process, as already explained with reference to Fig. 3.

[0070] The measurement by the measuring and testing device 13 can be stopped after a specified time and / or after the threshold value has been exceeded. Thus, the first termination criterion for the measurement can be the exceeding of the threshold value. If the threshold value is not exceeded within a specified time, this can serve as the second termination criterion for the measurement.

[0071] Furthermore, it is preferably provided here that the measuring and testing device 13 has an evaluation unit 20. This is particularly advantageous if the temperature and / or temperature change is measured using a thermal imaging camera, for example an infrared camera. The images recorded by the thermal imaging camera can then be evaluated directly by the evaluation unit 20. Here and preferably, the evaluation unit 20 is designed to automatically detect the counter support surface 9 and / or the test area 14. The evaluation unit 20 can thus mask out irrelevant areas of the joining partner 2, the carrier 3 and / or the fastening means 4, such as the head section 7, and / or disregard them during the measuring process. At the same time, the test area 14 can be automatically detected and evaluated accordingly.It is then not necessary to point the sensor and / or the thermal imaging camera exclusively at the test area 14.

[0072] Furthermore, it is preferably provided here that the measuring and testing device 13 has a documentation unit 21 or is coupled to a documentation unit 21, and that the documentation unit 21 is designed to assign a quality criterion to each joining partner 2 that has been connected to a carrier 3, depending on the measured temperature and / or the temperature change. The term "coupled" is understood here to mean at least a signal-related connection, i.e., a connection that allows at least the transmission of information and / or a signal from the measuring and testing device 13 to the documentation unit 21.

[0073] In a particularly simple case, the quality criterion can assume a positive value, which indicates that the engagement of the support surface 8 with the counter-support surface 9 has been detected by the temperature measurement and / or temperature change, or a negative value, which indicates that the engagement of the support surface 8 with the counter-support surface 9 has not occurred due to the temperature measurement and / or temperature change. In this way, it is possible to document which joining partner 2 has been connected to a carrier 3 according to the target assembly state, for example within the framework of a quality assurance system. In this way, the quality of the connection between the joining partner 2 and the carrier 3 can be monitored even with large quantities, and a quality criterion can be assigned to each connection. It is then possible to sort out individual connections or batches that do not correspond to the target assembly state.

[0074] Here and preferably, the quality criterion is stored to allow the quality criterion to be assigned to a specific joining process over a long period of time.

[0075] In the embodiment shown in the figures and preferred in this respect, it is provided that the joining device 1 has a control and regulation unit 22 or is electrically connected to a control and regulation unit 22, and that the control and regulation unit 22 is designed to change at least one joining parameter when joining the joining partner 2 to the carrier 3 as a function of the measured temperature and / or temperature change.

[0076] For example, it is possible to immediately repeat the joining process of a joining partner 2 with a carrier 3 with one or more modified joining parameters if it has been detected based on the measured temperature and / or temperature change that the engagement of the support surface 8 with the counter-support surface 9 has not occurred. For example, the fastening element 4, designed as a screw, can be tightened again with a higher torque M. This process can be repeated until the engagement of the support surface 8 with the counter-support surface 9 is detected or another termination criterion is met.

[0077] Alternatively or additionally, it is also conceivable that one or more joining parameters are adjusted for a subsequent joining process. For example, based on the finding that the previous joining process did not result in engagement of the support surface 8 with the counter-support surface 9, a joining parameter of the subsequent joining process can be changed. In the case of a screw as the fastening element 4, for example, the torque M can be increased.

[0078] Alternatively or additionally, one or more joining parameters can only be changed when specified change conditions are met. For example, a number of consecutive joining processes or a specified percentage of joining processes that have not resulted in engagement of the support surface 8 with the counter support surface 9 can trigger a change in a joining parameter.

[0079] In order to enable reliable joining of the joining partner 2 to the carrier 3, it is further preferably provided that the joining device 1 has at least one hold-down device 23 which holds the joining partner 2 and the carrier 3 in the unjoined state in a desired joining position in which the joining of the two components can take place. This then ensures that the joining partner 2 and the carrier 3 are arranged relative to one another in such a way that the two components can be joined reliably using the fastening means 4. From Fig. 1 and Fig. 2 it can be seen that incorrect positioning of the joining partner 2 relative to the carrier 3 makes insertion of the fastening means 4 and thus joining difficult and / or impossible.

[0080] Alternatively or additionally, it is also conceivable for the joining device 1 to have a position detection system for detecting a target joining position of the joining partner 2 and the carrier 3, in which the joining of the two components can take place. If the joining partner 2 and the carrier 3 are not in the target joining position, the initiation of the joining process can be prevented and, if necessary, an error message can be generated.

[0081] It is particularly advantageous if the joining partner 2, the carrier 3, and / or the fastening means 4 are made of plastic and / or metal. In the preferred embodiment shown in the figures, the joining partner 2 is made of plastic and the fastening means 4 is made of metal. With this material combination, the desired assembly state of the connection between the joining partner 2 and the carrier 3 can be determined particularly reliably by measuring the temperature and / or the temperature change of the joining partner 2 in the test area 14.

[0082] To prevent the temperature measurement in the test area 14 from being influenced by other heat sources, in particular radiation sources, the joining device 1 is provided with a shield 24 which, for shielding against external interference, in particular from other heat sources, at least partially encloses a joining area in which the joining partner 2 is connected to the carrier 3 by means of the fastening means 4. The use of a shield 24 is particularly useful when the joining partner 2 is made of a material with a low emissivity, for example, metal, and can reflect radiation from surrounding radiation and heat sources.

[0083] The term "joining area" is to be interpreted broadly here and understood as the area in which the connection between the joining partner 2 and the carrier 3 is established using the fastening means 4. In this case, the shielding 24 can only enclose, at least in sections, the joining area formed by the test area 14 and, for example, the head section ? and / or the fastening aid 10. Alternatively or additionally, it is also conceivable for the shielding 24 to enclose the entire joining partner 2, the entire carrier 3, and the entire fastening means 4, at least in sections.

[0084] In order to improve the measurement of the temperature and / or temperature change, it is preferably provided that the joining partner 2 and / or the fastening means 4 have a coating for changing the reflection, absorption and / or transmission at least in sections within the test area 14.

[0085] It is then possible, regardless of the material, to improve the measurement of temperature and / or temperature change in the test area 14 in a cost-effective manner.

[0086] Also claimed according to a further teaching, which is of independent significance, is a joining method for connecting a joining partner 2 to a carrier 3 by means of a fastening means 4 with a geometric fastening means axis A, in particular with a proposed joining device 1, wherein in the mounted state of the joining partner 2 on the carrier 3, the fastening means 4 has a shaft section 6 extending along the geometric fastening means axis A, which extends at least partially through the joining partner 2 and the carrier 3, and a head section 7 adjoining the shaft section 6 with a support surface 8 which, according to a desired assembly state, is in direct and / or indirect engagement with a counter support surface 9 of the carrier 3, wherein the joining partner 2 is connected to the carrier 3 by means of a fastening means 4,wherein the indirect and / or direct engagement of the support surface 8 with the counter support surface 9 is determined by means of a measuring and testing device 13.

[0087] It is now essential that the temperature and / or the temperature change of the joining partner 2 and / or the fastening means 4 is measured in a test area 14 adjacent to the support surface 8 and / or the counter-support surface 9, and that the indirect and / or direct engagement of the support surface 8 with the counter-support surface 9 is detected based on the measured temperature and / or temperature change. Reference may be made to all explanations of the proposed joining device 1 in this regard. It is then possible to detect in a particularly simple and reliable manner whether the connection of the joining partner 2 to the carrier 3 using the fastening means 4 has been completed in accordance with the desired assembly state.

[0088] It is particularly advantageous if a characteristic value is formed from the measured temperature and / or temperature change, and the indirect and / or direct engagement of the support surface 8 with the counter-support surface 9 is detected by exceeding a threshold characteristic value. Here, and preferably, a quality signal is generated when the threshold characteristic value is exceeded.

[0089] Furthermore, it is preferably provided here that each joining partner 2 that has been connected to a carrier 3 is assigned a quality criterion depending on the temperature measurement and / or the temperature change. In this simple manner, a quality system can be created that assigns a quality criterion to each joined component consisting of a joining partner 2 with the aid of a fastening means 4 and a carrier 3. The quality criterion here is preferably a criterion for whether the support surface 8 rests on the counter-support surface 9.

[0090] A particularly simple and effective control of the joining process can be achieved if at least one joining parameter is changed when joining the joining partner 2 with the carrier 3 as a function of the measured temperature and / or temperature change.

[0091] List of reference symbols

[0092] 1 joining device

[0093] 2 joining partners

[0094] 3 carriers

[0095] 4 fasteners

[0096] 5 Joining device

[0097] 6 Shaft section

[0098] 7 Head section

[0099] 8 support surface

[0100] 9 Counter support surface

[0101] 10 fastening aids

[0102] 11 outside contour

[0103] 12 radial edge contour

[0104] 13 Measuring and testing equipment

[0105] 14 Test area

[0106] 15 Outer contour

[0107] 16 radial outer contour

[0108] 17 Exterior area

[0109] 18 Front side

[0110] 19 axial outer contour

[0111] 20 evaluation unit

[0112] 21 Documentation Unit

[0113] 22 Control and regulation unit

[0114] 23 hold-down clamps

[0115] 24 Shielding

[0116] A geometric fastening center axis n speed

[0117] M torque

Claims

Patent claims 1. A joining device for connecting a joining partner (2) to a carrier (3) by means of a fastening means (4) with a geometric fastening means axis (A), wherein the joining device (1) has a joining device (5) for connecting the joining partner (2) to the carrier (3) by means of the fastening means (4), wherein, in the assembled state of the joining partner (2) to the carrier (3), the fastening means (4) has a shaft section (6) extending along the geometric fastening means axis (A), which extends at least partially through the joining partner (2) and the carrier (3), and a head section (7) adjoining the shaft section (6) with a support surface (8) which, according to a desired assembly state, is in direct and / or indirect engagement with a counter-support surface (9) of the carrier (3),wherein the joining device (1) has a measuring and testing device (13) for detecting the indirect and / or direct engagement of the support surface (8) with the counter-support surface (9), characterized in that the measuring and testing device (13) is designed to measure the temperature and / or the temperature change of the joining partner (2) and / or the fastening means (4) within a test area (14) adjacent to the support surface (8) and / or the counter-support surface (9) and to detect the indirect and / or direct engagement of the support surface (8) with the counter-support surface (9) based on the measured temperature and / or temperature change.

2. Joining device according to claim 1, characterized in that the fastening means (4) is designed as a screw and / or has a screw.

3. Joining device according to claim 1 or 2, characterized in that the measuring and testing device (13) is designed to form a characteristic value from the measured temperature and / or temperature change and to detect the engagement of the support surface (8) with the counter-support surface (9) by exceeding a limit threshold characteristic value, preferably that the measuring and testing device (13) is designed to generate a quality signal when the limit threshold characteristic value is exceeded.

4. Joining device according to claim 3, characterized in that the limit threshold characteristic value corresponds to a temperature value, or that the limit threshold characteristic value corresponds to a temperature change, or that the limit threshold characteristic value corresponds to a temperature change within a predetermined time.

5. Joining device according to one of the preceding claims, characterized in that the measuring and testing device (13) is designed for contactless measurement of the temperature and / or the temperature change and that the measuring and testing device (13) has at least one optical sensor for contactless measurement of the temperature and / or temperature change of the carrier (3) within the test area (14), in particular a thermal imaging camera and / or at least one pyroelectric sensor.

6. Joining device according to one of the preceding claims, characterized in that the measuring and testing device (13) is designed to continuously measure the temperature and / or the temperature change of the joining partner (2) and / or the fastening means (4) in the test area (14), or that the measuring and testing device (13) is designed to start the measuring process as a function of a start signal, in particular as a function of a start signal generated by the joining device (5), preferably that the start signal is generated when a limit threshold value of a joining parameter is exceeded, undershot or reached when the joining partner (2) is connected to the carrier (3), further preferably that the limit threshold value corresponds to a force, a torque (M) or a speed (n).

7. Joining device according to one of the preceding claims, characterized in that the measuring and testing device (13) has an evaluation unit (20), preferably that the evaluation unit (20) is designed for automatic detection of the counter support surface (9) and / or the test area (14).

8. Joining device according to one of the preceding claims, characterized in that the joining device (1) has a documentation unit (21) or is coupled to a documentation unit (21), and that the documentation unit (21) is designed to assign a quality criterion to each joining partner (2) that has been connected to a carrier (3) as a function of the measurement of the temperature and / or the temperature change.

9. Joining device according to one of the preceding claims, characterized in that the joining device (1) has a control and regulation unit (22) or is electrically connected to a control and regulation unit (22), and in that the control and regulation unit (22) is designed to change at least one joining parameter when joining the joining partner (2) to the carrier (3) as a function of the measured temperature and / or temperature change.

10. Joining device according to one of the preceding claims, characterized in that the joining device (1) has a hold-down device (23) which holds the joining partner (2) and the carrier (3) in the unjoined state in a desired joining position in which the joining of the two joining parts can be started, or that the joining device (1) has a position detection for detecting a desired joining position of the joining partner (2) and the carrier (3) in which the joining of the two joining parts can be started.

11. Joining device according to one of the preceding claims, characterized in that the joining partner (2), the carrier (3) and / or the fastening means (4) is made of plastic and / or metal, preferably that the joining partner (2) is made of plastic and the fastening means (4) is made of metal.

12. Joining device according to one of the preceding claims, characterized in that the joining device (1) has a shield (24) which, for shielding against interference, in particular from other heat sources, at least partially encloses a joining area formed by the joining partner (2), the carrier (3) and the fastening means (4).

13. Joining device according to one of the preceding claims, characterized in that the joining partner (2) and / or the fastening means (4) at least partially within the test area (14) have a coating for changing the reflection, absorption and / or transmission.

14. Joining method for connecting a joining partner (2) to a carrier (3) using a fastening means (4) with a geometric fastening means axis (A), in particular with a joining device (1) according to one of the preceding claims, wherein, in the mounted state of the joining partner (2) on the carrier (3), the fastening means (4) has a shaft section (6) extending along the geometric fastening means axis (A), which extends at least partially through the joining partner (2) and the carrier (3), and a head section (7) adjoining the shaft section (6) with a bearing surface (8) which is in direct and / or indirect engagement with a counter-contact surface of the carrier (3), wherein the joining partner (2) is connected to the carrier (3) using a fastening means (4),wherein the indirect and / or direct engagement of the support surface (8) with the counter-support surface (9) is determined by means of a measuring and testing device (13), characterized in that the temperature and / or the temperature change of the joining partner (2) and / or the fastening means (4) is measured in a test area (14) adjacent to the support surface (8) and / or the counter-support surface (9), and that the indirect and / or direct engagement of the support surface (8) with the counter-support surface (9) is detected on the basis of the measured temperature and / or temperature change.

15. Joining method according to claim 14, characterized in that a characteristic value is formed from the measured temperature and / or temperature change and that the indirect and / or direct engagement of the support surface (8) with the counter-support surface (9) is detected by exceeding a limit threshold characteristic value, preferably that a quality signal is generated when the limit threshold characteristic value is exceeded.

16. Joining method according to claim 14 or 15, characterized in that each joining partner (2) which has been connected to a carrier (3) is provided with a Quality criterion is assigned depending on the measurement of temperature and / or temperature change.

17. Joining method according to one of claims 14 to 16, characterized in that at least one joining parameter is changed when joining the joining partner (2) to the carrier (3) as a function of the measured temperature and / or temperature change.

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