Conductor track assembly for a temperature sensor, temperature sensor, and method for producing a temperature sensor

Abstract

The invention relates to a conductor track assembly (1) for a temperature sensor (2) having a sensor element (3), in particular an NTC element, wherein the conductor track assembly (1) comprises at least one conductor track (4) and a plastic part (5) which receives at least some parts of the at least one conductor track (4), and the at least one conductor track (4) has, at at least one end, a length subdivision in the form of a plurality of recesses (6) which are preferably arranged at regular distances (a) to one another. The invention also relates to a temperature sensor (2) having a conductor track assembly (1) according to the invention and to a method for producing a temperature sensor (2) using a conductor track assembly (1) according to the invention.

Description

[0001] Description

[0002] Conductor assembly for a temperature sensor, temperature sensor and method for manufacturing a temperature sensor

[0003] The invention relates to a conductor assembly for a temperature sensor. Furthermore, the invention relates to a temperature sensor comprising a conductor assembly according to the invention and a method for manufacturing a temperature sensor using a conductor assembly according to the invention.

[0004] Preferred applications include hydrogen tank valves that incorporate a temperature sensor for measuring the temperature in the hydrogen tank.

[0005] State of the art

[0006] Hydrogen tank valves are known for both withdrawing hydrogen from and filling a hydrogen tank. Such a hydrogen tank valve incorporates at least one controllable shut-off valve. In addition, further valves and / or sensors, particularly a temperature sensor for monitoring the temperature inside the hydrogen tank, are typically integrated.

[0007] Integrating a temperature sensor into a hydrogen tank valve involves inserting the sensor into a receiving bore and connecting its electrical terminals. This connection is typically made via a connector located in a separate bore, often at an angle, particularly a right angle, to the receiving bore. The two bores are connected by an intersection. Because the sensor is intended to measure the temperature inside the hydrogen tank, but the electrical connections are made outside the tank via this intersection, the temperature sensor must be of a certain length. Depending on the application, this length may vary, requiring either length adjustments or the availability of a variety of different temperature sensors.The latter is uneconomical.

[0008] The present invention is therefore concerned with the objective of providing a temperature sensor for a hydrogen tank valve whose overall length can be adjusted as easily as possible.

[0009] To solve the problem, the conductor track assembly with the features of claim 1 is proposed. Advantageous embodiments of the invention are described in the dependent claims. Furthermore, a temperature sensor and a method for manufacturing a temperature sensor are proposed.

[0010] Disclosure of the invention

[0011] A conductor assembly for a temperature sensor with a sensor element, in particular an NTC element, is proposed. The conductor assembly comprises at least one conductor and a plastic part that accommodates at least one conductor, at least partially. The at least one conductor has a longitudinal subdivision at at least one end in the form of several recesses, which are preferably arranged at regular intervals.

[0012] The recesses of the at least one conductor track in the proposed conductor track assembly not only create length divisions but also clearly defined areas where the conductor track can be easily cut to length, for example, by cutting or punching. This is because the recesses reduce the conductor track's cross-section, similar to a predetermined breaking point. Advantageously, the recesses are arranged at regular, and in particular uniform, intervals from one another, allowing the conductor track to be cut to length in defined steps or jumps. These steps or jumps are adapted to the specific lengths of various temperature sensors, enabling the same conductor track to be used in all of them. For the preferred application of the conductor track or conductor track assembly in a temperature sensor for a hydrogen tank valve, the distance between the recesses is preferably 10 mm to 30 mm.A simple pair of metal shears can be used to cut the conductor track to length. For high-volume industrial production, highly automated processes are recommended. For example, laser or waterjet cutting can be used. Punching also allows for a high degree of automation. Alternatively, the different lengths can be produced directly.

[0013] The proposed conductor track assembly allows for the creation of a wide variety of temperature sensors by adjusting their length. Furthermore, the use of identical components reduces manufacturing costs for temperature sensors.

[0014] The proposed conductor track assembly comprises at least two parts: a conductor track and a plastic part. Since a sensor element, such as an NTC element, has two connecting wires, each of which must be connected to a conductor track, the proposed conductor track assembly preferably comprises at least three parts: two conductor tracks and a plastic part for at least partially accommodating the two conductor tracks.

[0015] The two conductor tracks are preferably identical, thus further reducing manufacturing costs. Preferably, the conductor tracks embedded in the plastic part run parallel to each other at a distance. This distance prevents contact between the two conductor tracks and thus a short circuit. If the ends of the two conductor tracks are bent, for example to form a contact tab, the arrangement of the two conductor tracks is preferably rotated 180° relative to each other. This ensures that even the bent ends of the two conductor tracks do not make contact.

[0016] Furthermore, it is proposed that the at least one conductor track is a stamped / bent part. This allows for simple and cost-effective production of the at least one conductor track. The stamping tool can also be used to cut the conductor track to length. Alternatively, etching of the conductor tracks can be used, particularly for small production runs. According to a preferred embodiment of the invention, the plastic part forms at least one longitudinal groove for receiving the at least one conductor track. The plastic part supports and simultaneously provides electrical insulation for the conductor track. Preferably, the longitudinal groove is deep enough that the side walls defining the longitudinal groove extend beyond the conductor track received in the longitudinal groove. Since the proposed conductor track assembly preferably comprises two conductor tracks, the plastic part preferably also forms two parallel longitudinal grooves. Each longitudinal groove then receives one conductor track.A ridge of the plastic part remaining between the two longitudinal grooves prevents contact between the two conductor tracks.

[0017] To simplify the insertion of the at least one conductor track into the plastic part during assembly of the conductor track assembly, a further development of the invention proposes that the at least one longitudinal groove be chamfered along at least one longitudinal edge. The longitudinal groove thus opens outwards, which facilitates the insertion of the conductor track.

[0018] Furthermore, it is proposed that the width of at least one longitudinal groove be slightly larger than the width of the conductor track included therein, so that there is some play when inserting the conductor track.

[0019] To secure the at least one conductor track within the longitudinal groove, it is proposed that the plastic part form clamping lugs projecting into the at least one longitudinal groove to grip the conductor track securely. The clamping lugs are preferably arranged on opposite sides of the longitudinal groove and offset from each other along the longitudinal direction of the groove.

[0020] Alternatively or additionally, it is proposed that the plastic part has at least one pin extending transversely to the at least one longitudinal groove, which is deformable under the influence of temperature. The pin can then be deformed in such a way that it fills the space above the conductor track held in the longitudinal groove, thus securing the conductor track in the longitudinal groove. Preferably, the plastic part has several pins arranged at regular intervals along the at least one longitudinal groove. In this way, multiple retention points can be created, preventing the conductor track from falling out of the longitudinal groove.

[0021] As a further development measure, it is proposed that the at least one conductor track, which is embedded at least partially in the plastic part, has a recess in the area of ​​the at least one pin for a positive-locking connection with the pin. This positive lock is then achieved by deforming the pin under the influence of heat, whereby a portion of the pin material is pressed into the recess of the conductor track. This not only protects the conductor track from falling out of the longitudinal groove but also from longitudinal displacement relative to the plastic part. The deformation of the pin can be achieved, for example, using a thermode for hot or warm staking.

[0022] According to a preferred embodiment of the invention, the plastic part has a modular structure and comprises a base body, at least one spacer element, and a support element for receiving the sensor element. The modular structure allows for length adjustment of the plastic part by varying the number of parts, particularly the number of spacers. In its shortest version, the plastic part can consist solely of the base body and the support element. To enable greater lengths, one or more spacers can be inserted between the base body and the support element. All spacers can be identical, allowing for the production of plastic parts of varying lengths using identical components. The high number of identical components, in turn, reduces manufacturing costs.The modular plastic part allows for length adjustment by combining the individual modules according to the building block principle.

[0023] To coordinate the length adjustment of the plastic part and that of the at least one conductor track, it is proposed as a further development measure that the at least one spacer element of the plastic part has a length adapted to the distance maintained between the steps of the conductor track. For each step when cutting the conductor track to length, one fewer spacer element can then be used, so that the lengths of the at least one conductor track and the plastic part continue to match optimally. The plastic part accommodating the at least one conductor track is preferably an injection-molded part or a 3D-printed part. As an injection-molded part, the plastic part is particularly easy and cost-effective to manufacture. Due to the large number of identical parts, the same injection molds can also be used. Furthermore, overmolding of the at least one conductor track can be omitted, since it is preferably inserted into the plastic part subsequently.This allows for a simpler injection mold design, as the support required for the conductor track during overmolding is eliminated. Precise positioning of the conductor track within the mold is also unnecessary. Alternatively, a 3D printing process can be used to manufacture the plastic part, particularly for small production runs.

[0024] Since the proposed conductor assembly is used particularly in a temperature sensor, a temperature sensor comprising a sensor element, in particular an NTC element, and a conductor assembly according to the invention is further proposed. The conductor assembly according to the invention allows for length adjustment of the temperature sensor, thus making it versatile in its application. Since a large number of identical parts are used, manufacturing costs for the temperature sensor can be reduced.

[0025] Preferably, the sensor element of the proposed temperature sensor is embedded in the plastic part of the circuit board assembly and electrically connected to at least one conductor of the circuit board assembly, for example, by resistance welding. The circuit board assembly thus provides the necessary contact for the electrical connections of the sensor element. Furthermore, it optimally supports the sensor element, including its electrical connections, which may be connecting wires. In the modular design of the plastic part of the circuit board assembly, the sensor element, including its electrical connections, is supported by the support element, which—depending on the length of the temperature sensor—is attached to the base body of the plastic part either directly or indirectly via at least one spacer element.

[0026] According to a preferred embodiment of the invention, the

[0027] The sensor element is inserted into the carrier element of the modular plastic part of the conductor assembly. The sensor element can be fixed in the carrier element—analogous to the fixing of the at least one conductor track in the plastic part—by hot or warm riveting at least one temperature-deformable pin. This means that the carrier element also forms at least one such pin. The same preferably applies to the at least one spacer element of the plastic part, in order to fix the at least one conductor track within the spacer element.

[0028] In a further development of the invention, it is proposed that the conductor track assembly be surrounded by a sensor sleeve, at least in the area of ​​the inserted sensor element. The sensor sleeve protects the sensor element from external influences, in particular from harmful mechanical and / or chemical effects. Temperature sensors that are installed in different lengths generally require sensor sleeves of varying lengths. With the proposed conductor track assembly, the length of the sensor sleeve can be adjusted to accommodate these different lengths, allowing the proposed conductor track assembly to be used in all such temperature sensors. This avoids a high degree of component variation.

[0029] Furthermore, a method for manufacturing a temperature sensor using a conductor assembly according to the invention is proposed. The method comprises the steps: a) pre-assembling the conductor assembly, b) inserting a sensor element, in particular an NTC element, into the pre-assembled conductor assembly, c) connecting the sensor element to the at least one conductor track of the pre-assembled conductor assembly, and d) inserting the pre-assembled conductor assembly, including the sensor element, into a sensor sleeve of a predetermined length.

[0030] To adapt the length of the pre-assembled conductor assembly to the length of the sensor sleeve, the following steps precede step (a):

[0031] (i) Cutting or punching the at least one conductor track to length, (ii) Adjusting the length of the plastic part to the length of the at least one conductor track by inserting at least one spacer between a base body and a support element of the plastic part or by removing at least one spacer inserted between the base body and the support element.

[0032] The proposed method allows for the production of a wide variety of temperature sensors of different lengths, all consisting essentially of the same components. This reduces manufacturing costs. Furthermore, fewer parts need to be kept in stock, thus minimizing storage costs.

[0033] Preferably, during the pre-assembly of the conductor track assembly in step (a), the at least one conductor track is inserted into the plastic part and fixed in place. This fixing prevents relative movement of the at least one conductor track with respect to the plastic part and thus avoids undesired changes in length. The fixing is preferably achieved by hot or warm stapling. For this purpose, the plastic part can have at least one pin that is deformable under the influence of temperature. If the plastic part has a modular structure, each module preferably has at least one such pin.

[0034] The invention and its advantages are explained in more detail below with reference to the accompanying drawings. These show:

[0035] Fig. 1 a) to c) each shows a top view of a conductor track for a conductor track assembly according to the invention,

[0036] Fig. 2 a) to c) each shows a top view of a pair of conductor tracks analogous to Figure 1 in combination with a plastic part and a sensor element for the production of a temperature sensor,

[0037] Fig. 3 a) to c) each shows a top view of a fully assembled temperature sensor, comprising the components shown in Figure 2 plus a sensor sleeve,

[0038] Fig. 4 shows a top view of a pre-assembled conductor track assembly according to the invention with an inserted sensor element, Fig. 5 a) shows a perspective view of the pre-assembled conductor track assembly according to the invention of Figure 4 and b) shows an enlarged detail of Figure 5a).

[0039] Fig. 6 shows a cross-section through a pre-assembled conductor track assembly according to the invention and

[0040] Fig. 7 a) a top view of a plastic part of a conductor track assembly according to the invention and b) an enlarged section of figure 7a).

[0041] Detailed description of the drawings

[0042] A conductor assembly 1 according to the invention comprises at least one conductor 4 and a plastic part 5 for receiving the at least one conductor 4. Figures 1a) to 1c) each show, by way of example, one conductor 4 of a conductor assembly 1 according to the invention, whereby the same conductor 4 may be shown. In Figure 1a), the conductor 4 is not cut to length, so that it has a maximum length. In Figure 1b), the conductor 4 is cut to length once, and in Figure 1c), it is cut to length twice by a defined length. For this purpose, the conductor 4 has recesses 6 at one end, which are arranged at equal intervals a from each other. The recesses 6 create a subdivision of the conductor 4. At the same time, the conductor 4 can be cut to length once in the area of ​​the recesses 6.

[0043] On the other hand, the depicted conductor track 4 has an angled end to form a contact flag.

[0044] A conductor track assembly 1 according to the invention preferably comprises two such conductor tracks 4, which are received in parallel longitudinal grooves 7 of the plastic part 5. However, before the conductor tracks 4 are inserted into the longitudinal grooves 7, the length of the plastic part 5 is adapted to the length of the conductor tracks 4.

[0045] Figures 2a) to 2c) show, by way of example, two conductive traces 4 and a plastic part 5, the lengths of which correspond to the lengths of the conductive trace 4 shown in Figures 1a) to 1c). To prevent a short circuit via the end contact lugs, the two conductive traces 4, which each form a pair of conductive traces, are arranged rotated 180° relative to each other. Analogous to the conductive traces 4, the length of the plastic part 5 can also be adjusted. The plastic part 5 is modularly constructed for this purpose. The modules comprise a base body 5.1, at least one spacer element 5.2, and a support element 5.3, which serves to accommodate a sensor element 3, in particular an NTC element. The length of the assembled plastic part 5 can be determined by means of the at least one spacer element 5.2, with the length I being adapted to the distance a between the recesses 6 of the conductive traces 4.In Figure 2a), the two conductor tracks 4 are at their maximum length, so that several spacers 5.2 must be inserted between the base body 5.1 and the support element 5.3 to achieve the correct length. In Figure 2b), the conductor tracks 4 are each cut to a single length. To adjust the length of the plastic part 5 to the length of the conductor tracks 4, only one spacer 5.2 needs to be removed. In Figure 2c), the two conductor tracks 4 are cut to a double length. By removing both spacers 5.2, the length of the plastic part 5 can be adjusted to the length of the conductor tracks 4. In Figure 2c), the support element 5.3 follows directly after the base body 5.1.

[0046] After the conductor tracks 4 and the plastic part 5 have been adjusted to the correct length, these parts can be pre-assembled into a conductor track assembly 1. First, the modules of the plastic part 5 are joined. Then, the conductor tracks 4 are inserted into the longitudinal grooves 7 of the plastic part 5. In an advantageous embodiment of the plastic part 5, the longitudinal grooves 7 have chamfered longitudinal edges 8 (see Figure 6), which facilitates the insertion of the conductor tracks 4 into the longitudinal grooves 7. The conductor tracks 4 can be fixed in the longitudinal grooves 7 by hot or warm crimping. For this purpose, the plastic part 5 has pins 10 extending transversely to the longitudinal grooves 7 (see Figures 2a) to 2c)), which are deformable under the influence of heat.When the pins 10 are deformed, pin material is pressed into recesses 11 in the conductor tracks 4 (see Figure 5b), thus creating a positive fit that not only prevents the conductor tracks 4 from falling out of the longitudinal grooves 7, but also from longitudinal displacement relative to the plastic part 5. For this purpose, the pins 10 are arranged at regular intervals along the longitudinal grooves 7 (see Figure 5a and Figure 6). Alternatively or additionally, the longitudinal grooves 7 can have a certain amount of play relative to the cross-section of the conductor tracks 4 to facilitate the insertion of the conductor tracks 4. In this case, the plastic part 5 preferably has clamping lugs 9 projecting into the longitudinal grooves 7, which are arranged on opposite sides of the longitudinal grooves 7 and offset from each other along the longitudinal direction of the longitudinal grooves 7. This embodiment is shown by way of example in Figures 7a) and 7b), whereby the clamping lugs 9 are only visible in Figure 7b).

[0047] The sensor element 3 can then be inserted and secured into the pre-assembled conductor track assembly 1. An example of such an assembly is shown in Figure 4. To manufacture a temperature sensor 2, the assembly, with the sensor element 3 leading, is then inserted into a sensor sleeve 12. Depending on the installation situation, the length of the sensor sleeve 12 can vary. Examples can be found in Figures 3a) to 3c). By adjusting the lengths of the conductor tracks 4 and the plastic parts 5 beforehand, each conductor track assembly 1 can be adapted to the respective length of the sensor sleeve 12.

[0048] A temperature sensor 2, as illustrated by way of example in Figures 3a) to 3b), can be installed, in particular, in a hydrogen tank valve (not shown) to measure the temperature in the hydrogen tank. Installation must be carried out in such a way that no hydrogen escapes from the hydrogen tank to the outside. Therefore, an O-ring 14 is preferably arranged on the sensor sleeve 12 as a sealing ring and fixed by means of a support ring 13.

Claims

Claims 1. Conductor assembly (1) for a temperature sensor (2) with a sensor element (3), in particular an NTC element, wherein the conductor assembly (1) comprises at least one conductor (4) and a plastic part (5) which receives at least one conductor (4) at least partially, and wherein the at least one conductor (4) has at least one end a length division in the form of several recesses (6) which are preferably arranged at regular intervals (a) to each other.

2. Conductor assembly (1) according to claim 1 , characterized in that the at least one conductor (4) is a stamped / bent part.

3. Conductor assembly (1) according to claim 1 or 2, characterized in that the plastic part (5) forms at least one longitudinal groove (7), preferably two parallel longitudinal grooves (7), for receiving the at least one conductor track (4).

4. Conductor assembly (1) according to one of the preceding claims, characterized in that the at least one longitudinal groove (7) is chamfered along at least one longitudinal edge (8).

5. Conductor assembly (1) according to one of the preceding claims, characterized in that the plastic part (5) forms clamping lugs (9) projecting into the at least one longitudinal groove (7) for clamping the at least one conductor (4), which are preferably arranged on opposite sides of the longitudinal groove (7) and offset from each other in the longitudinal direction of the longitudinal groove (7).

6. Conductor assembly (1) according to one of the preceding claims, characterized in that the plastic part (5) has at least one pin (10) extending transversely to the at least one longitudinal groove (7), which is deformable under the influence of temperature, wherein preferably several pins (10) are arranged at regular intervals to each other along the at least one longitudinal groove (7).

7. Conductor assembly (1) according to claim 6, characterized in that the at least one conductor (4) which is received at least partially in the plastic part (5) has a recess (11) in the area of ​​the at least one pin (10) for a positive connection with the pin (10).

8. Conductor assembly (1) according to one of the preceding claims, characterized in that the plastic part (5) is modular and has a base body (5.1), at least one spacer element (5.2) and a support element (5.3) for receiving the sensor element (3), wherein preferably the at least one spacer element (5.2) has a length (I) adapted to the distance (a).

9. Conductor assembly (1) according to one of the preceding claims, characterized in that the plastic part (5) is an injection molded part or a 3D printed part.

10. Temperature sensor (2) with a sensor element (3), in particular an NTC element, and a conductor assembly (1) according to one of the preceding claims, wherein preferably the sensor element (3) is inserted into the plastic part (5) of the conductor assembly (1) and is electrically connected to the at least one conductor (4) of the conductor assembly (1), for example by resistance welding.

11. Temperature sensor (2) according to claim 10, characterized in that the sensor element (3) is inserted into the carrier element (5.3) of the modularly constructed plastic part (5).

12. Temperature sensor (2) according to claim 10 or 11, characterized in that the conductor track assembly (1) is surrounded by a sensor sleeve (12) at least in the area of ​​the inserted sensor element (3).

13. Method for manufacturing a temperature sensor (2) using a conductor assembly (1) according to any one of claims 1 to 9, comprising the steps a) pre-assembling the conductor assembly (1), b) inserting a sensor element (3), in particular an NTC element, into the pre-assembled conductor assembly (1), c) connecting the sensor element (3) to the at least one conductor (4) of the pre-assembled conductor assembly (1), and d) inserting the pre-assembled conductor assembly (1) including the sensor element (3) into a sensor sleeve (12) of a predetermined length, wherein the following steps precede step (a) to adapt the length of the pre-assembled conductor assembly (1) to the length of the sensor sleeve (12). (i) Cutting the at least one conductor track (4) to length by cutting or punching, (ii) Adjusting the length of the plastic part (5) to the length of the at least one conductor track (4) by inserting at least one spacer element (5.2) between a base body (5.1) and a support element (5.3) of the plastic part (5) or by removing at least one spacer element (5.2) inserted between the base body (5.1) and the support element (5.3).

14. Method according to claim 13, characterized in that, during the pre-assembly of the conductor track assembly (1) in step (a), the at least one conductor track (4) is inserted into the plastic part (5) and fixed, preferably by hot or warm riveting.

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