Weighing sensor

Abstract

Weighing sensor (1) with a first holder (2), a second holder (4), a sensor carrier element (8) held by the two holders (2, 4) and carrying a sensor element (6), and a sensor housing (10), wherein the sensor element (6) is arranged on a carrier bridge (12) of the sensor carrier element (8), and wherein the carrier bridge (12) is arranged between the two holders (2, 4), and the sensor housing (10) accommodates the carrier bridge (12) with the sensor element (6), wherein the sensor housing (10) has a sensor container (22) and a container lid (24), and wherein the carrier bridge (12) is led out of the sensor housing (10) between the sensor container (22) and the container lid (24) to the first holder (2) and to the second holder (4), characterized in that the sensor container (22) and the container lid (24) each have an elastic seal (26, 28), by means of which seals (26,28) the sensor housing (10) is sealed off from the support bridge (12), wherein the seal (26) of the sensor container (22) forms an uninterrupted container sealing surface (46) running around a container edge of the sensor container (22) relative to the support bridge (12) and relative to the container lid (24), and wherein the seal (28) of the container lid (24) forms an uninterrupted lid sealing surface (60) running around a lid edge of the container lid (24) relative to the support bridge (12) and relative to the sensor container (22).

Description

[0001] The invention relates to a weighing sensor comprising a first holder, a second holder, a sensor support element held by the two holders and carrying a sensor element, and a sensor housing. The sensor element is arranged on a support bridge of the sensor support element, and the support bridge is arranged between the two holders, and the sensor housing accommodates the support bridge with the sensor element. Furthermore, the invention relates to the use of such a weighing sensor and to a motor vehicle having such a weighing sensor.

[0002] For example, a weight sensor as mentioned above for attachment to an axle of a motor vehicle, in particular a commercial vehicle, is known. The weight sensor is attached to the axle using two brackets. The weight sensor can detect a deformation of the vehicle axle, and from this deformation, a weight load on the vehicle axle can be determined. Using such an axle load measurement of the motor vehicle, for example, the vehicle's own weight can be measured.

[0003] Mounted on the vehicle axle, the weight sensor is subject to a wide range of environmental influences. The sensor housing is provided to protect the weight sensor, and in particular its sensor element, from mechanical damage or moisture, for example. However, the problem arises of sealing the sensor housing and the sensor element from the environment.

[0004] DE 10 2018 221 808 A1, in turn, discloses a weighing sensor with two holders and a sensor support element held by the two holders and carrying a sensor element. The sensor element is arranged on a support bridge of the sensor support element, which support bridge is arranged between the two holders.

[0005] EP 0 969 265 A1, in turn, generally discloses a sensor comprising a sensor carrier element held by two holders and carrying a sensor element, as well as a housing. The housing encloses a coating compound made of a flexible material with elastic properties, which protects the sensor element. However, the housing itself does not have any seals to protect the interior from the ingress of dirt or moisture.

[0006] WO 2017 / 066508 A1 discloses a sensor that can have a strain gauge as its sensor element, comprising a sensor support element and a housing accommodating the sensor element. The housing has an upper housing section and a lower housing section. The sensor support element is arranged between an upper and lower housing section. Two sealing rings are located on the sensor support element, which seal the housing at the points where the sensor support element passes through. The upper and lower housing sections snap together and engage with the sealing rings.

[0007] The object of the invention is to create a weighing sensor of the type mentioned above, whose sensor element is particularly well and permanently protected against environmental influences. Furthermore, the object of the invention is to specify a use for such a weighing sensor. A further object of the invention is to create a motor vehicle with such a weighing sensor.

[0008] The first-mentioned object is achieved according to the invention with a weighing sensor of the type mentioned at the outset and in that the sensor housing has a sensor container and a container lid, and that the support bridge is led out of the sensor housing between the sensor container and the container lid to the first holder and to the second holder. According to the invention, the sensor container and the container lid each have an elastic seal by means of which seals the sensor housing is sealed off from the support bridge, wherein the seal of the sensor container forms an uninterrupted container sealing surface running all the way around a container edge of the sensor container relative to the support bridge and relative to the container lid, and wherein the seal of the container lid forms an uninterrupted lid sealing surface running all the way around a lid edge of the container lid relative to the support bridge and relative to the sensor container.

[0009] Advantageously, in the invention, protection by the sensor housing is directed, preferably limited, to those components that are particularly sensitive to environmental influences, such as the sensor element and, if applicable, other components, particularly electronic components, required for the operation of the sensor element. A particularly large sensor housing, which for example has to be sealed off from a vehicle axle, is not required with the invention. The invention can also advantageously concentrate on sealing the sensor housing from the support bridge. The holders that serve to fasten the weighing sensor according to the invention, for example to a vehicle axle, are arranged outside the sensor housing. The holders offer the additional advantage that a weighing sensor according to the invention can be mounted in a particularly simple manner, for example to a vehicle axle of a motor vehicle, even subsequently (e.g.as a retrofit sensor) and can be easily replaced with another corresponding weighing sensor, for example in the event of a defect in a weighing sensor on the vehicle axle.

[0010] Another particular advantage of the invention is that the elastic seals of the sensor container and the container lid ensure that the interior of the sensor housing is impermeable and sealed against, for example, the ingress of dirt or moisture, and also mechanically decouple the support bridge with the sensor element on the one hand from the sensor housing on the other. The sensor container is preferably cuboid-shaped. Further preferably, the sensor housing is cuboid-shaped.

[0011] For example, one could imagine the elastic seal of the sensor container being inserted into a rigid container part of the sensor container. However, it is particularly advantageous for reliable and simple production of the weighing sensor, even in large series, if, according to a further development of the invention, the sensor container is a multi-component plastic component with a rigid container component and an elastic container component, with the elastic container component containing the seal of the sensor container. The multi-component plastic component can, for example, be a two-component plastic component.

[0012] By the seal of the sensor container forming a container sealing surface running all the way around a container edge of the sensor container relative to the support bridge and relative to the container lid, an uninterrupted container sealing surface is created at the container edge, whereby a particularly reliable and permanent seal of the sensor housing can be achieved. By designing the container lid seal in the form of a lid sealing surface running all the way around a lid edge of the container lid relative to the support bridge and relative to the sensor container, a particularly good and reliable sealing effect can also be achieved. This creates an uninterrupted lid sealing surface. Electronic components, which may be required, for example, for operating the sensor element, can advantageously be arranged in the sensor housing. For connecting the sensor element and, if applicable, such aforementioned electronic components to, for example,A cable connection can be provided between a vehicle electronics system of a motor vehicle, for example, an evaluation electronics system of an on-board weighing system (the vehicle's own weighing system). According to an advantageous development of the invention, the sensor container has a cable feedthrough, and the elastic container component has a cable seal for the cable feedthrough. As a result, the elastic container component can be used in a particularly simple and reliable manner to seal the sensor housing against a cable, e.g., an electrical cable, leading through the cable feedthrough into the sensor housing for connecting the sensor element and, for example, the vehicle electronics.

[0013] According to another advantageous development of the invention, the elastic container component has a locking lug for holding an electronic component arranged in the sensor container. More than one such locking lug can also be provided on the elastic container component. The locking lug or lugs is / are directed in particular into the interior of the sensor container. The electronic component held by the at least one locking lug is in particular a circuit board or a circuit board section, e.g., a circuit board section of a rigid-flex circuit board or a flex circuit board. Due to the holding by the locking lug, the electronic component and, if applicable, other electronic components arranged on this electronic component are protected, for example, from damage due to vibrations that can occur during operation of a weighing sensor according to the invention, e.g., in a motor vehicle.Furthermore, the locking lug can simplify the production of the weighing sensor. The fact that the elastic container component has the locking lug means that the locking lug itself is also elastic. This offers, among other things, the additional advantage of making the locking lug easy to manufacture via forced demolding. For example, complex slide inserts in a manufacturing tool, such as an injection mold, for the sensor container are then no longer required.

[0014] According to another advantageous development of the invention, the container lid is a multi-component plastic component with a rigid lid component and an elastic lid component, wherein the elastic lid component comprises the seal of the container lid. This allows the container lid to be manufactured particularly easily and reliably. The multi-component plastic component can, for example, be a two-component plastic component.

[0015] According to another advantageous development of the invention, the container rim with the container sealing surface and / or the lid rim with the lid sealing surface has an edge recess that accommodates the support bridge. The edge recess can, in particular, be U-shaped. In particular, the edge recess can surround the support bridge on three sides. By means of the edge recess that accommodates the support bridge, not only is a reliable seal of the sensor housing achieved in the area of ​​the support bridge, but also a particularly reliable mechanical decoupling of the support bridge and the sensor housing is achieved.

[0016] According to another advantageous development of the invention, the sensor container and / or the container lid has a positioning recess, and the sensor carrier element has a positioning lug that engages in the positioning recess. This enables particularly simple and error-free assembly of the weighing sensor. It is also conceivable in this development of the invention for the lug and recess to be arranged in reverse, i.e., for the sensor carrier element to have the positioning recess, and for the sensor container and / or the container lid to have the positioning lug that engages in the positioning recess.

[0017] The sensor element could, for example, be a distance-detecting sensor element. However, an advantageous development of the invention provides that the sensor element is a strain sensor element that detects a strain of the support bridge. The strain sensor element detects a strain, which can be a positive or negative strain and thus also includes, for example, a compression, of the support bridge. If the holder of the weighing sensor is attached, in particular rigidly, to a vehicle axle, a strain of the vehicle axle on which the weighing sensor is arranged can also be detected accordingly. The strain sensor element can, for example, have one or more strain gauges.

[0018] According to another advantageous development of the invention, the sensor container is filled with a potting compound on its interior, wherein the sensor element is arranged outside the potting compound. In particular, the entire support bridge with the sensor element can be arranged outside the potting compound. This means that the sensor element, preferably the entire support bridge with the sensor element, is thus arranged freely in space within the sensor housing. In contrast, any further electronic components arranged in the sensor housing are preferably enclosed in the potting compound. With the development of the invention, the sensor container can be particularly well sealed, and components arranged in it can be additionally protected, while at the same time preventing the sensor element from being subjected to particular mechanical stresses, e.g.due to different thermal expansion coefficients of the potting compound and the support bridge and / or the sensor element, which could lead to damage to the sensor element and / or to falsification of the measurement results of the weighing sensor.

[0019] The second object mentioned above is achieved by using a weighing sensor according to the invention in an on-board weighing system of a motor vehicle. Such an on-board weighing system is also referred to as an on-board weighing system. The motor vehicle can, in particular, be a commercial vehicle, e.g., a truck, a construction machine, or an agricultural vehicle. In particular, the use according to the invention can comprise using the weighing sensor on a vehicle axle of the motor vehicle.

[0020] The third object mentioned above is achieved with a motor vehicle having a vehicle axle and with a weighing sensor according to the invention arranged on the vehicle axle.

[0021] The invention also includes further developments of the inventive use of the weighing sensor as well as further developments of the motor vehicle according to the invention, which further developments have features as described in connection with the further developments of the weighing sensor according to the invention. For this reason, the corresponding further developments of the use and the motor vehicle are not described again here.

[0022] The invention also includes the combination of features of the described embodiments and further developments.

[0023] Embodiments of the invention are described in more detail below with reference to the drawing. The drawing shows a sketchy, schematic representation Fig. 1 a weighing sensor in a sectional view, Fig. 2 the weighing sensor in an exploded view, Fig. 3 a detail Y of the weighing sensor after Fig. 1, Fig. 4 the weighing sensor in a sectional view along line JJ in Fig. 1, Fig. 5 a detail Z of the weighing sensor after Fig. 4, Fig. 6 the weighing sensor in a sectional view along line CC in Fig. 4, Fig. 7 the weighing sensor in a sectional view along line BB to Fig. 4, Fig. 8 a sensor container of the weighing sensor in perspective view, Fig. 9 an elastic container component of the sensor container according to Fig. 8 in perspective view, Fig. 10 the elastic container component according to Fig. 9 in another perspective view, Fig. 11 a section of the weighing sensor in a perspective sectional view, Fig. 12 a container lid of the weighing sensor in perspective view, Fig. 13 the container lid Fig. 12 in a sectional view.

[0024] Corresponding elements are provided with the same reference numerals in all figures.

[0025] Fig. 1 shows a weighing sensor 1 with a first holder 2, a second holder 4, a sensor support element 8 held by the two holders 2, 4 and carrying a sensor element 6, and a sensor housing 10. The sensor element 6 is arranged on a support bridge 12 of the sensor support element 8. The support bridge 12 is arranged between the two holders 2, 4. The sensor housing 10 accommodates the support bridge 12 with the sensor element 6.

[0026] It can also be seen that the first holder 2 has an upper holding element 14 and a lower holding element 16, and that the second holder 4 has an upper holding element 18 and a lower holding element 20. The sensor carrier element 8 is clamped between the upper holding element 14 and the lower holding element 16 of the first holder 2, on the one hand, and the upper holding element 18 and the lower holding element 20 of the second holder 4, on the other hand.

[0027] The weight sensor 1 can, for example, be arranged on a vehicle axle in a motor vehicle (not shown here). For example, the weight sensor 1 can be screwed to the vehicle axle. The lower retaining element 16 of the first holder 2 and the lower retaining element 20 of the second holder 4 can rest, for example, on an axle housing of the vehicle axle.

[0028] The sensor housing 10 comprises a sensor container 22, here cup-shaped, and a container lid 24. The support bridge 12 extends out of the sensor housing 10 between the sensor container 22 and the container lid 24 to the first holder 2 and to the second holder 4. The sensor container 22 and the container lid 24 each have an elastic seal 26, 28, by means of which seals 26, 28 the sensor housing 10 is sealed against the support bridge 12.

[0029] In this embodiment, the sensor container 22 is filled with a potting compound 29, with the sensor element 6 being arranged outside the potting compound 29. An exemplary fill level 31 of the potting compound 29 is shown as a double-dotted line in Fig. 1. It can be seen that the entire support bridge 12 with the sensor element 6 is arranged outside the potting compound 29.

[0030] Fig. Figure 2 shows the weighing sensor 1 in an exploded view along with an electrical connecting cable 30. Using the connecting cable 30, the weighing sensor 1 can be connected, for example, to a motor vehicle's onboard weighing system. For mechanically locking the connecting cable 30 to the weighing sensor 1, the latter has a cable locking element 32. In an alternative embodiment, the connecting cable 30 can also be a component of the weighing sensor 1.

[0031] The first holder 2 and the second holder 4 each have two through-holes 34. By means of screw bolts (not shown here) extending through the through-holes 34, the weighing sensor 1 can be fastened, for example, to a vehicle axle, e.g., to an axle housing of the vehicle axle, of a motor vehicle.

[0032] The container lid 24 and the sensor container 22 are screwed together using two screws 36. A folded circuit board 38 with evaluation electronics 40 is arranged in the sensor container 22.

[0033] In a perspective view, Fig. 8 the sensor container 22. The sensor container 22 is a multi-component plastic component with a rigid container component 42 and an elastic container component 44. The elastic container component 44 (see also Fig. 9, Fig. 10) has the seal 26 of the sensor container 22.

[0034] The seal 26 of the sensor container 22 forms a container sealing surface 46 running around a container edge opposite the support bridge 12 and opposite the container lid 24 (cf. Fig. 3, Fig. 7).

[0035] In addition, the sensor container 22 has a cable feedthrough 48. Furthermore, the elastic container component 44 has a cable seal 50 for the cable feedthrough 48.

[0036] As in Fig. As can be seen in Figure 11, the elastic container component 44 has locking lugs 52 for holding an electronic component arranged in the sensor container 22. In this exemplary embodiment, the electronic component is a printed circuit board, specifically a rigid printed circuit board section 54 of the folded printed circuit board 38.

[0037] Fig. 12 and Fig. 13 show the container lid 24 in various representations. The container lid 24 is a multi-component plastic component with a rigid lid component 56 and an elastic lid component 58. The elastic lid component forms the seal 28 of the container lid 24. The seal 28 of the container lid 24 forms a lid sealing surface 60 running around a lid edge relative to the support bridge 12 and relative to the sensor container 22 (see also Fig. 3, Fig. 7).

[0038] Such as from Fig. 6 and Fig. As can be seen in Figure 8, the container rim with the container sealing surface 46 has a U-shaped edge recess 62 that accommodates the support bridge 12. The edge recess 62 is part of the elastic container component 44 and the seal 26 of the sensor container 22. The edge recess 62 surrounds the support bridge 12 on three sides. On the fourth side of the support bridge 12, on which side the support bridge 12 is not surrounded by the edge recess 62 and thus not by the sensor container 22, the support bridge 12 rests against the container lid 24, specifically against the seal 28 of the container lid 24.

[0039] From the Fig. 4 shows a sectional view of the weighing sensor 1 that on the one hand the sensor container 22 (see also Fig. 8) positioning recesses 64 and, on the other hand, the sensor carrier element 8 has positioning lugs 66 engaging in the positioning recesses 64. Furthermore, Fig. 4 (see also Fig.5) that the elastic container component 44 of the sensor container 22 has ribs 68 as elastic spacers relative to the sensor support element 8. Due to the ribs 68, an air gap 70 is created between the sensor container 22 and the sensor support element 8, which serves as a buffer zone in the event of, for example, temperature-related dimensional changes and prevents the introduction of forces into the sensor support element 8 and thus possibly also into the sensor element 6 due to such aforementioned dimensional changes.

[0040] In this exemplary embodiment, the sensor element 6 is a strain sensor element that detects the strain of the support bridge 12. For example, the sensor element 6 can comprise one or more strain gauges.

Claims

[1] Weighing sensor (1) with a first holder (2), a second holder (4), a sensor carrier element (8) held by the two holders (2, 4) and carrying a sensor element (6), and a sensor housing (10), wherein the sensor element (6) is arranged on a carrier bridge (12) of the sensor carrier element (8), and wherein the carrier bridge (12) is arranged between the two holders (2, 4), and the sensor housing (10) accommodates the carrier bridge (12) with the sensor element (6), wherein the sensor housing (10) has a sensor container (22) and a container lid (24), and wherein the carrier bridge (12) is led out of the sensor housing (10) between the sensor container (22) and the container lid (24) to the first holder (2) and to the second holder (4), characterized byin that the sensor container (22) and the container lid (24) each have an elastic seal (26, 28), by means of which seals (26, 28) the sensor housing (10) is sealed off from the support bridge (12), wherein the seal (26) of the sensor container (22) forms an uninterrupted container sealing surface (46) running all the way around a container edge of the sensor container (22) relative to the support bridge (12) and relative to the container lid (24), and wherein the seal (28) of the container lid (24) forms an uninterrupted lid sealing surface (60) running all the way around a lid edge of the container lid (24) relative to the support bridge (12) and relative to the sensor container (22). [2] Weighing sensor (1) according to claim 1, characterized bythat the sensor container (22) is a multi-component plastic component with a rigid container component (42) and with an elastic container component (44), wherein the elastic container component (44) has the seal (26) of the sensor container (22). [3] Weighing sensor (1) according to one of the preceding claims, characterized by that the sensor container (22) has a cable feedthrough (48) and that the elastic container component (44) has a cable seal (50) of the cable feedthrough (48). [4] Weighing sensor (1) according to one of the preceding claims, characterized by that the elastic container component (44) has a locking lug (52) for holding an electronic component arranged in the sensor container (22). [5] Weighing sensor (1) according to one of the preceding claims, characterized bythat the container lid (24) is a multi-component plastic component with a rigid lid component (56) and with an elastic lid component (58), wherein the elastic lid component (58) has the seal (28) of the container lid (24). [6] Weighing sensor (1) according to one of the preceding claims, characterized by that the container edge with the container sealing surface (46) and / or the lid edge with the lid sealing surface (60) has an edge recess (62) receiving the support bridge (12). [7] Weighing sensor (1) according to one of the preceding claims, characterized by that on the one hand the sensor container (22) and / or the container lid (24) has a positioning recess (64) and on the other hand the sensor carrier element (8) has a positioning lug (66) engaging in the positioning recess (64). [8] Weighing sensor (1) according to one of the preceding claims, characterized bythat the sensor element (6) is a strain sensor element which detects a strain of the support bridge (12). [9] Weighing sensor (1) according to one of the preceding claims, characterized by that the sensor container (22) is filled in its interior with a potting compound, wherein the sensor element (6) is arranged outside the potting compound. [10] Use of a weighing sensor (1) according to one of the preceding claims in an on-board weighing system of a motor vehicle. [11] Motor vehicle with a vehicle axle and with a weighing sensor (1) arranged on the vehicle axle according to one of claims 1 to 9.

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