Testing device and test probe for a testing device

Abstract

The invention relates to a testing device (2) designed to test a wiring system plug connector (4) for proper assembly of a number of plug contacts (6) of the plug connector (4) and comprising an electromechanical measuring device (10) with at least one test probe (12), the at least one test probe (12) having a sleeve (16) and a test needle (18) held by the sleeve (16), the test needle (18) as viewed in a longitudinal direction (14) having three sections (18a, 18b, 18c), namely an upper section (18a), a middle section (18b) and a lower section (18c), with the middle section (18b) of the test needle (18) electrically insulating the upper section (18a) from the lower section (18c), wherein the test needle (18) is displaceable in a longitudinal direction (14) so that a longitudinal position of the test needle (18) can be changed, and wherein the measuring device (10) is designed to determine the longitudinal position of the test needle (18) in a measuring process by means of a capacitive measurement.

Description

[0001] Description

[0002] Test device and test pin for a test device

[0003] The invention relates to a test device for testing a connector for an on-board electrical system for the correct assembly of a number of connector contacts. The invention also relates to a test pin for such a test device.

[0004] A connector designed for a vehicle electrical system usually has a number of connector contacts which are to be inserted into a connector housing of the connector during assembly of the connector.

[0005] Since replacing a connector after installation in a motor vehicle can sometimes involve considerable effort and / or a defect in a connector can lead to the failure of a safety-relevant function in the motor vehicle, there is typically a requirement to check the correct rusting of the connector contacts at least on a random basis for individual connectors during the manufacture of such connectors.

[0006] For this purpose, a test fixture with several test pins is typically used. The connector is placed on the test fixture with its plug contacts facing forward until the individual test pins each make electrical contact with a plug contact. This checks the correct installation position of the plug contacts. Performing the test can be complex. Based on this, the invention is based on the object of enabling a simple and reliable test of a connector for an on-board electrical system to ensure that a number of the connector contacts are correctly installed.

[0007] This object is achieved according to the invention by a testing device having the features of claim 1 and by a test pin having the features of claim 24. Preferred developments are contained in the dependent claims. The advantages and preferred embodiments cited with regard to the testing device are also transferable to the test pin, and vice versa.

[0008] The test device according to the invention serves to test a connector, specifically an electrical connector designed for use in an on-board electrical system, in particular in the on-board electrical system of a motor vehicle. A corresponding connector has a number of connector contacts, i.e., at least one connector contact and typically two or more connector contacts. Such a connector contact is usually made of a metal or a metal alloy and is designed, for example, as a contact pin or contact sleeve.

[0009] The test device is now configured to check the correct assembly of a number of plug contacts of the connector, and in particular to check the correct assembly of all plug contacts of the connector. Preferably, the test device is configured to check whether the number of plug contacts of the connector is correctly installed in a plug housing of the connector.

[0010] Furthermore, the test device comprises an electromechanical measuring device with at least one test pin. Preferably, the test device comprises more than one test pin, for example four, six or eight test pins. In particular, the test device comprises a test pin for each provided plug contact of the connector. Preferably, at least two of the test pins of the test device are designed in the same way and, in particular, all test pins of the test device are designed in the same way, namely according to the type of at least one

[0011] Test pin

[0012] Irrespective of this, the at least one test pin is typically elongated in a longitudinal direction. It comprises a sleeve and a test needle held by the sleeve. Typically, the test needle, on the one hand, and the sleeve, on the other, are each elongated in the longitudinal direction. Furthermore, the test needle is expediently located at least partially within the sleeve, similar to, for example, a ballpoint pen refill within a ballpoint pen. In this case, the test needle is displaceable or held displaceably, such that the test needle is displaceable in the longitudinal direction, i.e., in particular, displaceable relative to the sleeve. Thus, the longitudinal position of the test needle is variable.

[0013] The measuring device comprising the at least one test pin, i.e., the electromechanical measuring device, is further configured to determine the longitudinal position of the test needle of the at least one test pin during a measuring process by means of a capacitive measurement. For this purpose, the testing device, and in particular the electromechanical measuring device, preferably comprises a control and evaluation unit by means of which the capacitive measurement is controlled, performed, and / or evaluated.

[0014] Capacitive measurement allows the longitudinal position of the test probe to be determined reliably and easily automatically. This longitudinal position allows conclusions to be drawn about the assembly of the plug contact under test, making it possible to verify whether the plug contact has been correctly installed.

[0015] Furthermore, the test needle of the at least one test pin has at least three sections, viewed in the longitudinal direction, namely an upper section, a middle section, and a lower section. The three sections are expediently connected to one another mechanically and / or by a material bond. The lower section is preferably made of a metal or a metal alloy. Typically, the upper section is also made of a metal or a metal alloy. The middle section, in contrast, is preferably made of an insulating material, for example a plastic, so that the middle section electrically insulates the upper section from the lower section.

[0016] Dividing the test needle into several electrically isolated sections provides the advantage that the lower and upper sections can have different reference potentials during testing. This makes it possible, in particular, to use the separate sections for different test steps. For example, the lower section is used for the desired capacitive measurement, while the upper section is used simultaneously for a resistance measurement or current conduction measurement. This therefore makes it possible, in particular, to determine both the position of the test needle and the electrical resistance to the plug contact—for example, simultaneously.

[0017] It is further expedient if the test device has a receptacle for the connector, for example, a slot into which the connector can be plugged for testing. The test device is then preferably configured such that, by inserting the connector into the receptacle, for example, by inserting it into the slot, the test needle of the at least one test pin is displaced differently depending on whether the connector contact to be tested is correctly mounted or not.

[0018] Furthermore, the test needle of the at least one test pin is preferably spring-loaded, in particular in such a way that a spring restoring force acting on the test needle is directed in the longitudinal direction. In this case, the sleeve and the test needle are coupled by a spring element, for example a helical spring. In an advantageous development, a restoring force is also predetermined in such a way that the restoring force is, on the one hand, sufficiently large to displace an incorrectly positioned plug contact relative to the plug housing of the connector, and, on the other hand, sufficiently small not to displace a correctly rusted plug contact relative to the plug housing of the connector. In this way, it is then possible to determine not only whether a plug contact is correctly positioned in the plug housing of the connector to be tested, but also whether it is correctly positioned.

[0019] The sleeve of the at least one test pin preferably has at least three sections, viewed in the longitudinal direction, namely an upper section, a middle section, and a lower section. The three sections are expediently connected to one another mechanically and / or by a material bond. The lower section is preferably made of a metal or a metal alloy. Typically, the upper section is also made of a metal or a metal alloy. The middle section, in contrast, is preferably made of an insulating material, for example a plastic, so that the middle section electrically insulates the upper section from the lower section.

[0020] It is further advantageous if the at least one test pin has at least three sections, viewed in the longitudinal direction, in at least one position of the test needle. The lower section is preferably made of a metal or a metal alloy. Typically, the upper section is also made of a metal or a metal alloy. The middle section, in contrast, is preferably made of an insulating material, for example, a plastic, so that the middle section electrically insulates the upper section from the lower section.

[0021] Particularly when the lower section of the sleeve is made of a metal or a metal alloy and the lower section of the test pin is made of a metal or a metal alloy, it is also advantageous if the lower section of the sleeve and the lower section of the test pin are electrically connected. The electrical connection is conveniently realized via a sliding contact or contact. Dividing the sleeve and / or the entire test pin into several electrically separate sections enables simple electrical connection, especially of the different sections of the test pin.

[0022] In an advantageous development, the lower section of the sleeve has a lower electrical connection, via which, for example, an electrical connection is established between the lower section of the test needle on the one hand and a measuring circuit and / or a previously mentioned control and evaluation unit on the other. The measuring device is then preferably configured to determine the longitudinal position of the test needle by means of the lower electrical connection using capacitive measurement.

[0023] The upper section of the sleeve and the upper section of the test needle are preferably electrically connected. The electrical connection is conveniently realized via a sliding contact or touch contact.

[0024] In an advantageous development, the upper section of the sleeve has an upper electrical connection, via which, for example, an electrical connection is established between the upper section of the test needle on the one hand and a measuring circuit and / or a previously mentioned control and evaluation unit on the other. The measuring device is then preferably configured to perform a current conduction measurement using the upper electrical connection, in particular a current conduction measurement across the plug contact to be tested. In this case, for example, a current intensity or an ohmic resistance is determined.

[0025] The test device is now configured to test the correct assembly of a number of plug contacts of the connector by determining the longitudinal position of the test needle of at least one test pin by means of capacitive measurement.

[0026] The measuring device preferably has a reference electrode, which, depending on the application, is plate-shaped, for example. It is also expedient if the reference electrode has a simple cuboid shape. In a slightly modified design variant of the reference electrode, it has a recess for the at least one test pin, which typically forms a blind hole or an opening. Furthermore, the test needle of the at least one test pin can then be displaced in the longitudinal direction such that, in at least one position of the test needle, the lower section of the test needle at least protrudes into the opening.

[0027] If the recess is designed as an opening, then the testing device according to at least one embodiment variant is also preferably designed such that the lower section of the test needle penetrates the opening if a correctly rusted plug contact is located in the contact receptacle tested with the at least one test pin. Further preferably, the lower section of the test needle then projects somewhat into the opening if a plug contact is located in the contact receptacle tested with the at least one test pin, but this plug contact is not properly rusted with the contact receptacle. And furthermore preferably, the lower section of the test needle does not project into the opening if there is no plug contact in the contact receptacle tested with the at least one test pin.

[0028] It is also advantageous if the test device has a guide for the test needle of at least one test pin. The guide is typically located in the area of ​​the reference electrode.

[0029] The guide aid further preferably has at least one guide plate, which is arranged in particular between the sleeve of the at least one test pin and the reference electrode. This at least one guide plate is typically arranged on an upper side of the reference electrode facing the sleeve and expediently has an opening for the at least one test pin as a guide for the test needle of the at least one test pin. Depending on the application, the edge of the at least one guide plate delimiting the opening forms a sliding bearing for the test needle. Also expedient is a variant of the testing device in which the guide aid has a further guide plate in addition to the previously described guide plate. This further guide plate is then arranged, for example, on an underside of the reference electrode opposite the upper side.In some applications, it has a recess for the at least one test pin, for example, a blind hole or an opening, as a guide for the test pin of the at least one test pin. Depending on the application, the edge of the second guide plate that defines the respective recess in turn forms a sliding bearing for the test pin.

[0030] If the test device has more than one test pin, as preferred and explained above, the following also applies:

[0031] - If the test device has a reference electrode and the reference electrode has a recess, the reference electrode typically has more than one recess, namely in particular one recess for each test pin.

[0032] - If the test device has a guide plate and this guide plate has an opening, this guide plate typically has more than one opening, namely in particular one opening for each test pin.

[0033] - If the test device additionally has a further guide plate and the further guide plate has a recess, the further guide plate typically has more than one recess, namely in particular one recess for each test pin.

[0034] Regardless of this, each of the guide plates of the guide aid is typically made of an electrically insulating material / material mix.

[0035] The previously described reference electrode is further arranged at a predetermined distance from the sleeve of the at least one test pin, viewed in the longitudinal direction, and is typically elongated transversely to the longitudinal direction. Furthermore, the reference electrode and the sleeve are expediently each arranged in a fixed position in the test device, so that the distance between the reference electrode and the sleeve is fixed. The fixed position is achieved, for example, by a housing or a support structure of the test device. The test pin, on the other hand, is displaceable in the longitudinal direction relative to the sleeve and thus also relative to the reference electrode. In this case, the longitudinal position of the test pin correlates with a distance between the test pin and the reference electrode.The measuring device is then further preferably configured to determine the distance between the test needle and the reference electrode in the measuring process by means of the capacitive measurement, wherein the test needle is used for this purpose as a counter electrode to the reference electrode.

[0036] If the test device has, in addition to the reference electrode, a previously mentioned receptacle for the connector, for example, a previously mentioned slot, the at least one test pin is also typically arranged between the receptacle and the reference electrode. In this case, a lower end of the at least one test pin faces the reference electrode, and an upper end of the at least one test pin, opposite the lower end in the longitudinal direction, faces the receptacle.

[0037] According to at least one preferred embodiment of the test device, the measuring device is further configured such that a voltage measurement is performed at the reference electrode for the capacitive measurement. Voltage measurement here specifically means that the electrical potential at the reference electrode is compared to a reference potential, with the potential difference then corresponding to a measurable voltage determined during the voltage measurement. Typically, a ground connection provides the reference potential, meaning that the electrical potential at the reference electrode is compared, in particular, to the ground potential.

[0038] According to an alternative design variant, a comparable voltage measurement is performed on the test needle instead of the reference electrode. This means that the electrical potential at the test needle is then compared with a corresponding reference potential. In such a case, the aforementioned lower electrical connection is preferably used for the voltage measurement.

[0039] Furthermore, a design of the test device is advantageous in which the measuring device is configured to apply a test voltage to the test needle during the measurement process. This means that an electrical potential is specified for the test needle with a specified difference from a reference potential. The electrical potential is then preferably specified via a previously mentioned lower electrical connection.

[0040] In particular, a preferred embodiment of the test device is one in which the measuring device has a charge pump with which the test voltage can be generated. During the test, a defined amount of charge is preferably applied to the test needle, which is designed as an electrode at least in some areas, so that a test voltage is established between the test needle and the reference potential. The measuring device is thus configured to apply the test voltage to the test needle during the measuring process.

[0041] According to an alternative design variant, such a test voltage is applied to the reference electrode instead of to the test needle.

[0042] Preferably, the measuring device is designed to determine the potential difference between the test needle and the reference electrode by a voltage measurement.

[0043] Regardless of the specific method used to perform the capacitive measurement, it serves to determine the longitudinal position of the test needle, whereby the longitudinal position of the test needle indicates whether the plug contact being tested is correctly mounted or not.

[0044] As already explained above, the test device preferably has a control and evaluation unit by means of which the capacitive measurement is controlled, carried out, and / or evaluated. The control and evaluation unit comprises, for example, a microcontroller for this purpose. A design in which the control and evaluation unit has an output unit, in particular an optical display unit, is also expedient. Furthermore, a conversion algorithm is preferably predefined in the control and evaluation unit, with which a measured value of the capacitive measurement is assigned to a test result, which is then output via the output unit.

[0045] In an advantageous development, the control and evaluation unit is also programmable and, in particular, parameterizable. In this case, not only the conversion algorithm can be adapted, but alternatively or additionally, the control and evaluation unit is configurable for different types of connectors, which differ, for example, in terms of the number of connector contacts and / or the intended installation depths / plug-in depths of the connector contacts.

[0046] Especially if the control and evaluation unit is programmable, it is preferably also equipped with access restrictions to prevent unauthorized access to the programming. This means, for example, that the evaluation unit is password-protected. This ensures reliable protection against tampering and thus reliable testing.

[0047] As already stated above, according to a preferred embodiment, the measuring device is configured to determine the distance between the test pin and the reference electrode during the measuring process by means of capacitive measurement, wherein the test pin is used as a counter electrode to the reference electrode. In this case in particular, the test pin of the at least one test pin is then expediently made at least partially of a metal or a metal alloy.

[0048] In the preceding explanations, reference was primarily made to the at least one test pin, and its design and function in the test device were described in more detail. However, as already explained above, preferred embodiments of the test device are those in which it has more than one test pin, and in which, more preferably, all test pins of the test device are designed similarly, namely in the manner of the at least one test pin.

[0049] If the test device and thus also the measuring device has several test pins, the measuring device is at least in some cases set up to determine the longitudinal positions of the test needles of the individual test pins in a sequence, one after the other, during the measuring process using a capacitive measurement. Thus, x capacitive measurements are then carried out in the measuring process if the test device has x test pins. Preferably, the longitudinal position of exactly one test needle is determined per measurement. For this purpose, the individual test pins are preferably charged successively using the charge pump. After the individual measurement has been carried out, the respective test pin is preferably discharged again and the next test pin is charged and discharged for the next individual measurement, and so on.

[0050] The measuring device is generally preferably configured such that, in the measuring process, during one of the capacitive measurements y for determining the longitudinal position of the test needle of a given test pin y, the aforementioned test voltage is applied to the test needle of the test pin y. Typically, the measuring device is then also configured such that, during the capacitive measurement y, a reference potential, for example a ground potential, is applied to the test needles of the remaining test pins of the test device.

[0051] This reference potential also advantageously corresponds to the reference potential that is preferably applied to the previously described reference electrode during the measurement process. The reference electrode then further preferably serves as a reference electrode for more than one test probe. In particular, it serves as a reference electrode for the test probes of all test probes of the test device.

[0052] If multiple test probes are present, it is also useful if the test probes are held by a common carrier plate. The test probes are, for example, plugged into the carrier plate. In an advantageous development, the carrier plate also serves as a stop for the connector to be tested. In this case, the carrier plate is thus part of the previously described connector holder.

[0053] In a preferred embodiment, the at least one test pin and in particular all test pins are interchangeable and / or the test needle of the at least one test pin and in particular all test needles are interchangeable.

[0054] To ensure the interchangeability of a test needle, the test needle and the associated sleeve are preferably designed such that the test needle can be rotated around its longitudinal axis relative to the sleeve for assembly. This creates a type of bayonet lock, for example.

[0055] As already explained above, according to at least one preferred embodiment of the test device, the measuring device is configured such that a voltage measurement is carried out on the reference electrode for the capacitive measurement and in particular for each of the capacitive measurements x.

[0056] Also advantageous are designs in which the measuring device has more than one reference electrode, for example, 2 reference electrodes. The reference electrodes are then usually arranged one behind the other in the longitudinal direction, and a distance is typically specified between the reference electrodes. Furthermore, the reference electrodes each have an opening for the at least one test pin, with the openings being aligned. If multiple test pins are present, each of the reference electrodes preferably has an opening for each test pin.

[0057] Apart from that, in these cases, the measuring device is preferably also configured such that multiple voltage measurements are performed for the capacitive measurement or each of the capacitive measurements x, namely, in particular, one at each reference electrode. Consequently, the measuring device then has a separate voltage measuring circuit for each reference electrode or is configured such that each reference electrode can be switched individually and, in particular, can be connected to a common voltage measuring circuit.

[0058] Further preferably, the measuring device is configured such that exactly z voltage measurements are performed for each of the capacitive measurements x. In this case, all z voltage measurements of a specific capacitive measurement y from x are then preferably evaluated together by the measuring device, and the longitudinal position of the associated test needle y is determined based on all z voltage measurements of a specific capacitive measurement y. Performing more than one voltage measurement per capacitive measurement typically enables the longitudinal position of a test needle to be determined with greater accuracy.

[0059] Depending on the application, the z voltage measurements of a capacitive measurement y from x are performed either simultaneously or sequentially. If the voltage measurements are performed sequentially, the reference electrodes at which no voltage measurement is currently being performed are typically connected to a ground potential, in particular to earth potential, for the duration of the measurement, for example, using a relay or transistor. The measuring device is then configured accordingly.

[0060] Particularly when the voltage measurements of a capacitive measurement y from x are to be carried out simultaneously, it is further advantageous if a shielding plate is arranged between two reference electrodes following one another in the longitudinal direction. Such a shielding plate serves to reduce the mutual influence of the reference electrodes. It is typically made of an electrically conductive material and is expediently connected to a ground potential at least for the duration of a previously described voltage measurement. The measuring device is then set up accordingly. If there are more than two reference electrodes, a shielding plate is typically arranged between each of the reference electrodes following one another in the longitudinal direction. Designs are also advantageous in which, alternatively or additionally, at least one guide plate of the guide aid is arranged between two reference electrodes following one another in the longitudinal direction.If there are more than two reference electrodes, at least one guide plate of the guide aid is typically arranged between all reference electrodes following one another in the longitudinal direction.

[0061] The following applies to each shielding plate described above, as well as to each guide plate described above: It expediently has an opening for the at least one test pin, with all openings for the at least one test pin being aligned. If multiple test pins are present, each of the plates preferably has an opening for each test pin.

[0062] The advantages and preferred embodiments mentioned with regard to the previously described test device are also to be transferred analogously to the previously described test pin and vice versa.

[0063] Embodiments of the invention are explained in more detail below with reference to a schematic drawing. In the drawing:

[0064] Fig. 1 shows a block diagram of a test device with three test pins,

[0065] Fig. 2 shows a simplified sectional view of part of the test device with a reference electrode in a first embodiment,

[0066] Fig. 3 in a simplified sectional view of one of the test pins,

[0067] Fig. 4 shows an enlarged section of a simplified sectional view of the reference electrode in a second embodiment together with a guide aid and

[0068] Fig. 5 shows an enlarged section of a simplified sectional view of a reference electrode stack.

[0069] Corresponding parts are provided with the same reference numerals in all figures. A test device 2, described below as an example and sketched in a block diagram in Fig. 1, is used to test an electrical plug connector 4 (cf. Fig. 2) which is designed for use in the on-board electrical system of a motor vehicle. In the exemplary embodiment, this plug connector 4 is designed to latchingly receive three plug contacts 6 and for this purpose has a plurality of contact receptacles in which a respective plug contact 6 can be inserted. For this purpose, each plug contact 6 typically has a latching element. Outgoing, single-core cables are preferably connected to the plug contacts 6.The test device 2 is now set up to check the correct assembly of the plug contacts 6 of the connector 2, in particular whether the plug contacts 6 are correctly rusted in the plug housing 8.

[0070] For illustration purposes, different situations are shown in the example shown in Fig. 2: The left contact receptacle contains a plug contact 6, which, however, is not properly rusted to the contact receptacle. The middle contact receptacle contains a correctly rusted plug contact 6. In contrast, the right contact receptacle does not contain a plug contact 6.

[0071] The test device 2 comprises an electromechanical measuring device 10 with a test pin 12 for each provided plug contact 6 or for each contact receptacle of the plug connector 4. Typically, a plurality of test pins 12 are provided so that the test device can be used for different plug connectors with different numbers of contact receptacles or plug contacts. In the exemplary embodiment, three test pins 12 are shown, as indicated in Fig. 2. The test pins 12 are designed identically.

[0072] Fig. 3 shows one of these test pins 12 in a simplified representation. The test pin 12 is elongated in a longitudinal direction 14. It has a sleeve 16 and a test needle 18 held by the sleeve 16. The test needle 18, on the one hand, and the sleeve 16, on the other hand, are each elongated in the longitudinal direction 14. Furthermore, the test needle 18 lies in the sleeve 16 and, in the exemplary embodiment, penetrates the sleeve 16. In addition, the test needle 18 is displaceable or held displaceably, such that the test needle 18 can be displaced in the longitudinal direction 16 relative to the sleeve, for example by a maximum of 3 mm or, for example, by a maximum of 5 mm. This means that a longitudinal position of the test needle 18 can then be changed.

[0073] As can also be seen from Fig. 3, the test needle 18 has three sections 18a, 18b, 18c, viewed in the longitudinal direction 14, namely an upper section 18a, a middle section 18b, and a lower section 18c. The three sections 18a, 18b, 18c are expediently connected to one another mechanically and / or by a material bond. The lower section 18c and the upper section 18a are electrically conductive and are made, in particular, of a metal or a metal alloy, and the middle section 18b is made of an electrically insulating material, for example, a plastic. Thus, the middle section 18b insulates the upper section 18a from the lower section 18c.

[0074] Furthermore, the sleeve 16 also has three sections 16a, 16b, 16c, viewed in the longitudinal direction 14, namely an upper section 16a, a middle section 16b, and a lower section 16c. These three sections 16a, 16b, 16c are also expediently connected to one another mechanically and / or by a material bond. The lower section 16c and the upper section 16a are again electrically conductive and are made in particular from a metal or a metal alloy, and the middle section 16b is made from an electrically insulating material, for example, a plastic. Thus, the middle section 16b insulates the upper section 16a from the lower section 16c.

[0075] As can be seen from Fig. 2, the lower section 16c of the sleeve 16 in the test device 2 has a lower electrical connection 20, via which an electrical connection is established between the lower section 16c of the sleeve 16, on the one hand, and a control and evaluation unit 22 of the electromechanical measuring device 10, on the other hand (see Fig. 1). Furthermore, the lower section 16c of the sleeve 16 is electrically conductively connected to the lower section 18c of the test needle 18. The electrical connection is realized via a sliding contact or contact.

[0076] Furthermore, the upper section 16a of the sleeve 16 in the test device 2 has an upper electrical connection 24, via which an electrical connection is established between the upper section 16a of the sleeve 16, on the one hand, and the control and evaluation unit 22, on the other. Furthermore, the upper section 16a of the sleeve 16 is electrically conductively connected to the upper section 18a of the test needle 18. The electrical connection is again realized via a sliding contact or touch contact.

[0077] As indicated in Fig. 2, the test device 2 further comprises a reference electrode 26, which is plate-shaped and made, for example, of copper or brass. It is elongated transversely to the longitudinal direction 14 and serves as a reference electrode 14 for all three test pins 12 and, in particular, for their test needles 18. The thickness of the reference electrode 14 is approximately 1 mm, depending on the application.

[0078] In the embodiment shown in Fig. 2, the test pins 12 are held by a common carrier plate 28. This carrier plate 28, together with further housing parts 30 of a housing of the test device 2 (not shown in full), forms a receptacle for the connector 2 to be tested. In Fig. 2, the connector 4 to be tested is positioned in the receptacle and thus ready for testing by the test device 2. As already mentioned, the connector 4 to be tested, shown in Fig. 2, has a correctly rusted connector contact 6 (center) and an incorrectly rusted connector contact 6 (left). The intended third connector contact 6 (right) is missing.

[0079] By positioning the connector 2 to be tested in the receptacle, the test needles 18 of the test device 2 were individually moved, depending on whether the respective connector contact 6 to be tested was correctly rusted, incorrectly rusted, or missing. This is at least indicated in Fig. 2. The test needles 18 of the test device 2 are spring-loaded in a manner not shown in detail, specifically such that a spring restoring force acting on the respective test needle 18 is directed in the longitudinal direction 14. For example, each sleeve 16 is coupled to its test needle 18 by a helical spring.

[0080] In an advantageous further development, the restoring force is also predetermined such that the restoring force is, on the one hand, sufficiently large to displace an incorrectly rusted plug contact 6 (left) relative to the plug housing 8 of the plug connector 4, and, on the other hand, is sufficiently small not to displace a correctly rusted plug contact 6 (central) relative to the plug housing 8 of the plug connector 4.

[0081] In order to check the correct assembly of the three provided plug contacts 6 in the inserted connector 6 by means of the test device 2, the control and evaluation unit 22 of the test device 2 is set up to carry out a sequence of three capacitive measurements, wherein each of the three capacitive measurements determines the longitudinal position for one of the test needles 18 and thus also how the longitudinal position has changed when the connector 6 to be tested is inserted into the receptacle.

[0082] During a corresponding capacitive measurement, a test voltage is now applied to one of the test needles 18 under the control of the control and evaluation unit 22. For this purpose, the test needle 18 is connected to a charge pump 32 of the control and evaluation unit 22 via the associated sleeve 16 and the associated lower electrical connection 20. This test needle 18 is then used as a counter electrode for the reference electrode 26 during this capacitive measurement under the control of the control and evaluation unit 22, while a voltage measurement is carried out at the reference electrode 26, namely by means of a measuring circuit 34 of the control and evaluation unit 22. During this capacitive measurement, the remaining two test needles 18 are preferably connected to ground under the control of the control and evaluation unit 22, namely via the associated lower electrical connections 20. The charged test needle 18 and the reference electrode 26 form electrodes of a capacitor.Based on the measured voltage, the distance of this test needle from the counter electrode, and thus its overall longitudinal position, is determined. Based on this measurement, a conclusion is then drawn as to whether the plug contact is correctly positioned. Such a measurement is performed successively for each of the test needles 18.

[0083] The three capacitive measurements are now used to determine the respective longitudinal positions of the three test needles 18, thus determining for each intended connector contact 6 whether it is correctly installed and, in particular, whether it is correctly rusted. The test result is then output via an output unit 36 ​​of the control and evaluation unit 22, controlled by the control and evaluation unit 22. The control and evaluation unit 22 typically has a microcontroller 38 for the control tasks.

[0084] With the aid of the previously described upper electrical connections 24 on the one hand and the measuring circuit 34 on the other, a further test controlled by the control and evaluation unit 22 is preferably carried out in parallel with the sequence of capacitive measurements. In this further test, current conduction measurements are typically performed via the upper electrical connections 20, in particular current conduction measurements across the plug contacts 6 to be tested. For example, a current intensity or an ohmic resistance is then determined for each test pin 12.

[0085] As previously explained, the reference electrode 26 of the test device 2 is plate-shaped in the exemplary embodiment. According to Fig. 2, the reference electrode 26 has a simple cuboid shape. Fig. 4 shows a slightly modified embodiment of the reference electrode 26. This is part of a slightly modified embodiment of the test device 2 and has an opening 40 for each test pin 12.

[0086] Furthermore, in the embodiment according to Fig. 4, each test needle 18 is displaceable in the longitudinal direction 14 such that, in at least one position, the lower section 18c of the test needle 18 at least projects into the associated opening 40. Depending on the application, the testing device 2 is then also designed such that the lower section 18c of the test needle 18 penetrates the associated opening 40 when a correctly rusted plug contact 6 is located in the contact receptacle tested with the corresponding test pin 12. More preferably, the lower section 18c of the test needle 18 projects somewhat into the associated opening 40 when a plug contact 6 is located in the contact receptacle tested with the corresponding test pin 12, but is not properly rusted with the contact receptacle.And furthermore, the lower section 18c of the test needle 18 preferably does not protrude into the corresponding opening 40 if there is no plug contact 6 in the contact receptacle tested with the corresponding test pin 12.

[0087] Furthermore, the test device 2 in the embodiment indicated in Fig. 4 has a guide plate 42, which is part of a guide aid 44. This guide plate 42 is arranged on an upper side 46 of the reference electrode 26 and has an opening 48 for each test pin 12, specifically as a guide for the associated test needle 18. Depending on the application, the edge of the guide plate 42 delimiting the respective opening 48 forms a sliding bearing for the associated test needle 18.

[0088] Also part of the guide aid 44 is a further guide plate 42, which is arranged on a bottom side 50 opposite the top side 46. This plate also has an opening 48 for each test pin 12 as a guide for the associated test needle 18. Depending on the application, the edge of the further guide plate 42 delimiting the respective opening 48 in turn forms a sliding bearing for the associated test needle 18.

[0089] The previously described guide plates 42 are preferably made of an electrically insulating material or material mix and typically each have a thickness of approximately 1 mm. The intermediate reference electrode 26 is typically made of copper or brass and has, for example, a thickness of approximately 1 mm. A further modified embodiment of the test device 2 is indicated in Fig. 5. Here, a reference electrode stack replaces the single reference electrode 26 from Fig. 2 or Fig. 4. In the exemplary embodiment, this reference electrode stack has three reference electrodes 26. In addition, four guide plates 42 are part of the reference electrode stack.

[0090] This means that in this embodiment of the test device 2, the guide aid 44 has four guide plates 42. A guide plate 42 is arranged between each two of the reference electrodes 26, and the reference electrode stack also terminates with a guide plate 42 on both the top side and the opposite bottom side.

[0091] The reference electrodes 26 and the guide plates 42 of the reference electrode stack, when considered individually, are similar to the reference electrode 26 and the guide plates 42 of the embodiment variant according to Fig. 4. Thus, the extension of the reference electrode stack in the longitudinal direction 14 is approximately 7 mm.

[0092] As already described above, in the embodiment with only one reference electrode 26 for each test pin, a capacitive measurement is carried out, in which the reference electrode 26 is used as a counter electrode and in which a voltage measurement is carried out at the reference electrode 26 by means of the measuring circuit 34 of the control and evaluation unit 22.

[0093] In the embodiment according to Fig. 5, each of these capacitive measurements comprises a voltage measurement at each reference electrode 26, i.e. a total of three voltage measurements.

[0094] The three voltage measurements are performed one after the other, with those reference electrodes 26 at which no voltage measurement is currently being performed being connected to a ground potential for the duration of the measurement. The measuring circuit 34 of the control and evaluation unit 22 is then configured accordingly. According to a further embodiment, the middle reference electrode 26 from Fig. 5 is replaced by a shielding plate. This differs from the middle reference electrode 26 according to Fig. 5 in its wiring. The shielding plate is wired in such a way that no voltage measurement can be performed on it. Instead, it is permanently connected to a ground potential terminal.

[0095] Thus, in this embodiment, two reference electrodes 26 remain, and two voltage measurements are taken for each of the capacitive measurements. However, these are preferably performed simultaneously.

[0096] The measurement concepts described above can be easily transferred to a larger number of reference electrodes 26. This means that in further embodiments, the reference electrode stack has more than three reference electrodes 26, for example, four, five, or more.

[0097] In all of the previously described embodiments, it is also advantageous if the capacitive measurements are performed shielded from the environment. Therefore, the test device 2 preferably has a shield 52. In Fig. 2, such a shield is indicated by a dashed frame. The shield 52 is designed such that it encloses a spatial area in which the reference electrode 26 or the reference electrode stack and the lower sections c of the test needles 18 are arranged.

[0098] The invention is not limited to the exemplary embodiment described above. Rather, other variants of the invention can also be derived therefrom by those skilled in the art without departing from the subject matter of the invention. In particular, all individual features described in connection with the exemplary embodiment can also be combined with one another in other ways without departing from the subject matter of the invention. List of reference symbols

[0099] 2 Test device

[0100] 4 connectors

[0101] 6 plug contact

[0102] 8 connector housings

[0103] 10 Measuring device

[0104] 12 test pin

[0105] 14 Longitudinal direction

[0106] 16 sleeve

[0107] 18 Test needle

[0108] 20 lower electrical connection

[0109] 22 Control and evaluation unit

[0110] 24 upper electrical connection

[0111] 26 Reference electrode

[0112] 28 Carrier plate

[0113] 30 Housing part

[0114] 32 Charge pump

[0115] 34 measuring circuit

[0116] 36 Output unit

[0117] 38 microcontrollers

[0118] 40 Breakthrough

[0119] 42 Guide plate

[0120] 44 Management aid

[0121] 46 Top

[0122] 48 Breakthrough

[0123] 50 subpage

[0124] 52 Shield a upper section b middle section c lower section

Claims

Claims Test device (2) designed to test a plug connector (4) for a vehicle electrical system for correct assembly of a number of plug contacts (6) of the plug connector (4) and comprising an electromechanical measuring device (10) with at least one test pin (12), wherein - the at least one test pin (12) has a sleeve (16) and a test needle (18) held by the sleeve (16), - the test needle (18) has three sections (18a, 18b, 18c) seen in a longitudinal direction (14), namely an upper section (18a), a middle section (18b) and a lower section (18c), - the middle section (18b) of the test needle (18) electrically insulates the upper section (18a) from the lower section (18c), - the test needle (18) is displaceable in the longitudinal direction (14) so ​​that a longitudinal position of the test needle (18) is variable, and - the measuring device (10) is configured to determine the longitudinal position of the test needle (18) by means of a capacitive measurement in a measuring process. Testing device (2) according to claim 1, wherein the sleeve (16) has three sections (16a, 16b, 16c) viewed in the longitudinal direction (14), namely an upper section (16a), a middle section (16b) and a lower section (16c), and wherein the middle section (16b) electrically insulates the upper section (16a) from the lower section (16c). Testing device (2) according to one of claims 1 to 2, wherein the at least one test pin (12) has three sections (a, b, c) viewed in the longitudinal direction (14), namely an upper section (a), a middle section (b) and a lower section (c), and wherein the middle Section (b) electrically insulates the upper section (a) from the lower section (c). Test device (2) according to claim 2 and claim 3, wherein the lower section (16c) of the sleeve (16) is electrically conductive, wherein the lower section (18c) of the test needle (18) is electrically conductive, and wherein the lower section (16c) of the sleeve (16) is electrically conductively connected to the lower section (18c) of the test needle (18). Test device (2) according to claim 4, wherein the lower section (16c) of the sleeve (16) has a lower electrical connection (20), and wherein the measuring device (10) is configured to determine the longitudinal position of the test needle (18) by means of the lower electrical connection (20) by means of the capacitive measurement.Test device (2) according to one of claims 2 to 5, wherein the upper section (16a) of the sleeve (16) is electrically conductive, wherein the upper section (18a) of the test needle (18) is electrically conductive, and wherein the upper section (16a) of the sleeve (16) is electrically conductively connected to the upper section (18a) of the test needle (18). Test device (2) according to one of claims 2 to 6, wherein the upper section (16a) of the sleeve (16) has an upper electrical connection (24), and wherein the measuring device (10) is configured to perform a current conduction measurement by means of the upper electrical connection (24). Testing device (2) according to one of claims 1 to 7, wherein the measuring device (10) has a reference electrode (26) which, viewed in the longitudinal direction (14), is arranged at a predetermined distance from the sleeve (16) of the at least one test pin (12), and wherein the measuring device (10) is set up to use the test needle (18) for the. capacitive measurement as a counter electrode to the reference electrode (26). Test device (2) according to claim 8, wherein the reference electrode (26) is plate-shaped. Test device (2) according to claim 8 or 9, wherein the reference electrode (26) has an opening (40) for the at least one test pin (12), and wherein the test needle (18) of the at least one test pin (12) is displaceable in the longitudinal direction (14) until the lower section (18c) of the test needle (18) projects into the opening (40). Test device (2) according to claim 10, wherein the measuring device (10) has at least one further reference electrode (26) in addition to the reference electrode (26), and wherein a distance is predetermined between each of the reference electrodes (26) as viewed in the longitudinal direction (14). Test device (2) according to claim 11, wherein the reference electrodes (26) are individually switchable.Testing device (2) according to claim 11 or claim 12, wherein, viewed in the longitudinal direction (14), a shielding plate is arranged between two consecutive reference electrodes (26). Testing device (2) according to one of claims 8 to 10, wherein the measuring device (10) has a guide aid (44) for the test needle (18) of the at least one test pin (12), and wherein the guide aid (44) is arranged in the region of the reference electrode (26). Testing device (2) according to claim 14, wherein the guide aid (44) has at least one guide plate (42), and wherein the at least one guide plate (42) has an opening (48). as a guide for the test needle (18) of the at least one test pin (12). Testing device (2) according to claim 15, wherein the opening (48) in the at least one guide plate (42) is delimited by an edge of the at least one guide plate (42), and wherein this edge forms a sliding bearing for the test needle (18) of the at least one test pin (12). Testing device (2) according to claim 15 or claim 16, wherein the at least one guide plate (42) is arranged between the sleeve (16) of the at least one test pin (12) and the reference electrode (26). Testing device (2) according to claim 17, wherein the at least one guide plate (42) is arranged on an upper side (46) of the reference electrode (26), and wherein a further guide plate (42) of the guide aid (44) is arranged on an underside (50) of the reference electrode (26) opposite the upper side (46).Testing device (2) according to one of claims 11 to 13, wherein the measuring device (10) has a guide aid (44) for the test needle (18) of the at least one test pin (12), wherein the guide aid (44) has a number of guide plates (42), wherein each guide plate (42) has an opening (48) as a guide for the test needle (18) of the at least one test pin (12), and wherein, viewed in the longitudinal direction (14), at least one guide plate (42) is arranged between two consecutive reference electrodes (26). Testing device (2) according to claim 19, wherein, viewed transversely to the longitudinal direction (14), the openings (40) of the reference electrodes (26) have a greater extent than the openings (48) of the guide plates (42). Test device (2) according to one of claims 8 to 10, wherein the measuring device (10) is configured to perform a voltage measurement at the reference electrode (26) during the measuring process. Test device (2) according to one of claims 1 to 20, wherein the measuring device (10) is configured to apply a test voltage to the test needle (18) during the measuring process. Test device (2) according to claim 22, wherein the measuring device (10) comprises a charge pump (32) for generating the test voltage. Test device (2) according to one of claims 1 to 23, wherein the measuring device (10) comprises a plurality of test pins (12), and wherein the measuring device (10) is configured to determine the longitudinal positions of the test needles (18) of the test pins (12) in a sequence one after the other in each case by means of a capacitive measurement during the measuring process. Test pin (12) for a test device (2) according to one of the preceding claims, wherein - it has a sleeve (16) and a test needle (18) held by the sleeve (16), - the test needle (18) is displaceable in a longitudinal direction (14) relative to the sleeve (16), - the test needle (18) has three sections (18a, 18b, 18c) viewed in the longitudinal direction (14), namely an upper section (18a), a middle section (18b) and a lower section (18c), and - the middle section (18b) electrically insulates the upper section (a) from the lower section (18c).

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