Active sensor with truck-specific housing

Abstract

The invention relates to a sensor device (S) for a commercial vehicle, in particular a rotational speed sensor. The invention relates to a sensor device (S) comprising a chip (1) with a sensor, which is arranged in a housing (3), the chip (1) being arranged in a waterproof manner with respect to the surroundings and being free of metal between the chip (1) and an object (O) to be sensed. Consequently, interfering eddy currents can be avoided, and a long service life of the sensor can be achieved through waterproofness.

Description

Technical Field

[0001] The present application relates to a sensor in a special housing for a truck, in particular to an active rotation speed sensor. Background Art

[0002] In commercial vehicles, wheel speed sensors are used, among other things, for anti-lock braking systems (ABS), electronic braking systems (EBS), electronic stability programs (ESP) and automated driving.

[0003] For example, in anti-lock braking systems (ABS), the rotational speed of individual vehicle wheels is detected. In commercial vehicles, in particular, passive, coil-based rotational speed sensors are used, which have no other function. In heavy-duty trucks (LKW), passive rotational speed sensors are secured using clamping sleeves. However, active rotational speed sensors (based on Hall or MR technology) are also used, particularly in the passenger car sector. These sensors are mounted in a manner oriented toward a pole wheel or encoder wheel.

[0004] Active speed sensors offer several advantages, as they can integrate several functions. However, these sensors must also be mounted or fixed appropriately at their location of use.

[0005] The prior art discloses, for example, document DE 10 2004 028 818 A1. This document discloses a rotational speed sensor having a housing that can be inserted into a holder, with the sensor being arranged inside the housing. Contact elements connected to the sensor connect the sensor to the outside of the housing. The housing can be inserted into the holder accordingly.

[0006] In commercial vehicles, different wiring paths are required compared to passenger cars, as these are typically much larger. Therefore, special precautions must be taken with regard to EMC (electromagnetic compatibility). Summary of the Invention

[0007] The object of the present invention is therefore to provide a rotational speed sensor which is axially displaceable and highly robust with respect to electromagnetic compatibility. This object is achieved by a sensor device according to claim 1. Further advantageous embodiments of the invention are the subject matter of the dependent claims.

[0008] The sensor device according to the invention comprises a chip having a sensor, which is arranged in a housing, wherein the chip is arranged waterproof relative to the surroundings and no metal is arranged between the chip and the object to be sensed.

[0009] This results in a very high mechanical robustness and can also ensure a very high robustness with respect to electromagnetic compatibility, since there is no interfering metal in the vicinity of the chip (or in the direct path between the sensor and the object to be sensed). Furthermore, damage to the chip can be avoided.

[0010] Preferably, the chip is a Hall element (further preferably a 2D / 3D Hall element), an R sensor, a GMR sensor or a TMR sensor, and is preferably implemented as a rotational speed sensor.

[0011] Such sensors are particularly useful in commercial vehicles. Further preferably, a chip comprises at least two active sensing areas. Three active sensing areas may also be provided, for example when both the rotational speed and the rotational direction are to be detected.

[0012] The housing may be made of metal, ceramic or composite material.

[0013] Preferably, the housing has a cylindrical, prismatic, or cuboid shape, and the chip is arranged near an end face of the housing. A borehole is provided in the end face, the extent of which further preferably corresponds at least to the extent of the chip. This ensures that no metal is present between the chip and the object to be sensed (e.g., a pole wheel or encoder wheel) that could interfere with electromagnetic detection.

[0014] This ensures that no metal is located between the effective sensing area of ​​the chip and the object to be sensed.

[0015] Furthermore, the housing is preferably tubular—in this case, the end faces are omitted, and here too, no metal is present between the chip and the object to be sensed (e.g., a pole wheel or encoder wheel). Furthermore, the production costs of a small tube (merely a tubular housing) are significantly lower than those of a sleeve. Furthermore, this improves electromagnetic compatibility, as eddy currents in the area of ​​the sensor chip can be reduced.

[0016] Preferably, a flange is provided on an end face of the housing, the chip is arranged near this end face, and the flange extends in the direction of the central axis of the housing, wherein preferably at least one hole is provided in the flange. The hole is used to allow water to flow out of the housing if it accumulates on the inside of the housing without reaching the chip.

[0017] Further preferably, the chip is arranged on a fixing section of a chip carrier, and the chip carrier is arranged inside the housing. The chip carrier further preferably includes a first retaining section and a second retaining section, wherein the first retaining section is opposite the first opening in the housing, and the second retaining section is opposite the second opening in the housing. These retaining sections can thus be fixed using a corresponding hold-down fixture (external retaining device for the overmolding process).

[0018] Furthermore, the housing is preferably filled with a polymer matrix which surrounds the chip carrier. This allows the chip carrier to be held in the housing when a hold-down tool is present and then to be encapsulated by injection molding.

[0019] Furthermore, the chip carrier preferably has a plurality of ribs adapted to abut against the inner side of the housing. Such ribs can also be designed as welding ribs, which secure the chip carrier to the housing and seal it so that no water can move inside the housing and, in particular, cannot penetrate into the area where the chip is located.

[0020] In another embodiment, the housing consists of a duroplast material which completely surrounds the chip and preferably also the chip carrier. In this embodiment, a sleeve or tube is no longer necessary to separate the sensor device from the outside.

[0021] Preferably, the sensor device is axially movable relative to the object to be sensed. This is advantageous, for example, when detecting the rotational speed of individual vehicle wheels.

[0022] Preferably, the sensor device is used in a commercial vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings.

[0024] Figure 1 A sensor arrangement according to the prior art is shown, wherein Figure 1 a) shows a cross-sectional view, Figure 1 b) shows an isometric view.

[0025] Figure 2 A first embodiment according to the present invention is shown. Figure 2 a) shows a cross-sectional view, Figure 2 b) and 2c) show detailed views of one side of the sensor arrangement, Figure 2 d) shows an isometric view of the sensor arrangement, Figure 2 e) shows a front view of the sensor device.

[0026] Figure 3 A second embodiment of the sensor arrangement according to the invention is shown in a sectional view.

[0027] Figure 4 The third embodiment of the present invention is shown. Figure 4 a) shows a cross-sectional view, Figure 4 b) shows an isometric view.

[0028] Figure 5 A detailed view is shown during the production of the sensor arrangement, in particular during the injection molding of the chip carrier with the base body (according to the first, second or third embodiment). Figure 5 b) and 5c) show respective partial views of the respective first and second holding sections.

[0029] Figure 6 A fourth embodiment of the present invention is shown. Figure 6 a) shows, in particular, a chip carrier. Figure 6 b) shows the corresponding isometric view.

[0030] Figure 7 A fifth embodiment of the present invention is shown. Figure 7 a) shows an isometric view, Figure 7 b) shows a front view. DETAILED DESCRIPTION

[0031] exist Figure 1 In a), a sensor arrangement S according to the prior art is shown in a sectional view.

[0032] The chip 1 is arranged on a chip carrier 2, more precisely on a chip fixing section 2c. The chip carrier 2 also has a first holding section 2a and a second holding section 2b. The chip carrier 2 including the chip 1 is arranged in a housing 3, which is implemented as a sleeve here - that is, it exists as a cylindrical shape and has a corresponding shell and cover. In addition, a seal 6 is provided on the outside of the housing 3. A cable 5 is provided on the side facing away from the chip 1, which connects the housing 3 to the surrounding environment. The chip carrier 2 is fixed inside the housing 3 and is injection-molded with a polymer matrix 4. Opposite to the first holding section 2a, a first opening 3b is provided in the housing 3, and correspondingly, opposite to the second holding section 2b, a second opening 3c is provided in the housing.

[0033] Figure 1 b) shows an isometric view of a sensor device S according to the prior art. It can be seen here that the cable 5 protrudes from the housing 3, and a first opening 3b is also provided in the housing. The second opening 3c is not shown here.

[0034] Figure 2 a) shows the Figure 1 A similar view, but this view here is based on the first embodiment of the invention. It can be seen here that a large borehole 3a is provided on the end side of the housing 3 so that no metal exists between the area where the chip 1 extends and the object O to be sensed (not shown here). All other sections are here identical. Figure 1 a) Exactly the same.

[0035] Figure 2b) shows a detailed view, in which the borehole 3a is also disclosed. In addition, a corresponding flange 3e is provided here, which extends slightly in the direction of the center axis of the housing 3. Here, the flange has an L-shaped shape. Figure 2 In c), the flange 3 e is likewise shown, but here it has a U-shape. Figure 2 d) shows a symmetrical view, again showing the housing 3 and the first opening 3b. The drilled hole 3a is clearly visible on the end face, and several holes 3d are provided on the flange 3e. These holes ensure that liquids can escape easily if they enter the interior of the housing 3. At the same time, the chip is sealed absolutely watertight from the surrounding environment by the polymer matrix 4 (not shown here). Figure 2 e) shows a front view, here also showing the opening 3a together with the corresponding hole 3d in the flange 3e.

[0036] Figure 3 A second embodiment of the present invention is shown. Figure 2 a) is similar, with the difference that here too two seals 6 are arranged on the outside of the housing 3, one on each side of the housing 3. Here too, there is a sleeve shape, ie a cylindrical housing and a cover.

[0037] Figure 4 Figure a) shows a third embodiment of the present invention. Here, the housing 3 is designed as a tube—that is, it has no end faces or covers, but only an outer surface. Here again, it can be seen that the first retaining section 2a and the second retaining section 2b are opposite the corresponding first opening 3b and second opening 3c in the housing 3, respectively.

[0038] Figure 4 b) shows an isometric view of a third embodiment, here again showing the housing 3 with the corresponding second opening 3c.

[0039] exist Figure 5 Schematic diagram a) shows a state during the production process of the sensor device, where it is disclosed in particular that a first hold-down tool S1 can be inserted through the first opening 3b and a second hold-down tool S2 can be inserted through the second opening 3c. During the encapsulation with the polymer matrix 4, these hold-down tools each hold the chip carrier 2 (the first hold-down tool S1 holds the first holding section 2a, the second hold-down tool S2 holds the second holding section 2b).

[0040] exist Figure 5b) shows two states during the injection molding process, namely how the second holding section 2b is held by the second holddown S2 from multiple sides. The left-hand view shows that the holddown S1 fixes the star-shaped section of the second holding section 2b, after which the corresponding area is freed up by the polymer matrix. The right-hand diagram shows a later state, in which the second holddown S2 has moved slightly away from the second holding section 2b, so that the immediately surrounding part of the second holding section 2b is injection molded. This ensures that there are no holes in the interior of the polymer matrix 4, and that the polymer matrix 4 seals the chip element 1 (not shown here) completely waterproof from the surrounding environment.

[0041] exist Figure 5 c) shows how the first holding section 2a is held by the first hold-down tool S1. Figure 5 b) shows a two-stage injection molding. In this case, holes may actually be produced, but Figure 5 As shown in a), these holes are located away from the sensor element 1 .

[0042] Figure 6 a) shows a fourth embodiment of the invention. Here, only the chip carrier 2 is shown, which again has a first holding section 2a and a second holding section 2b.

[0043] A plurality of ribs 7 are arranged along the chip carrier 2. These ribs can be designed, for example, as welding ribs (which, for example, weld when heated, thereby achieving a sealing effect). These ribs can seal the chip carrier 2 accordingly in a watertight manner relative to the housing 3 (not shown here), so that absolutely no water can flow in the direction of the chip 1 (correspondingly onto the chip mounting section 2c).

[0044] Figure 6 b) shows a corresponding isometric view of a chip carrier 2 according to a fourth embodiment.

[0045] Figure 7 a) shows an isometric view of a fifth embodiment of the present invention. Here again, a housing 3 is provided, from which a cable 5 extends. However, in this case, the chip 1 and the chip carrier 2 (not shown here) are completely surrounded by the thermosetting housing 3, i.e., the chip 1 and the chip carrier 2 (not shown here) are injection-molded with a thermosetting plastic.

[0046] There are two recesses 9 in the housing 3 , into which corresponding engagement sections 8 a of the clamping sleeve can engage, which makes the housing correspondingly more secure. Figure 7 b) shows a front view, in which the position of the two joining sections 8 a of the clamping sleeve 8 in the corresponding recesses 9 is again shown in more detail.

[0047] The present invention is not limited to the above-described embodiment.

[0048] The encapsulation can also be performed with other materials, for example rubber, gum or other waterproof materials.

[0049] Reference Signs List

[0050] S sensor device

[0051] 1 chip

[0052] 2 chip carrier

[0053] 2a First holding section

[0054] 2b Second holding section

[0055] 2c chip fixed section

[0056] 3 Shell

[0057] 3a Drilling

[0058] 3b First opening

[0059] 3c second opening

[0060] 3D Hole

[0061] 3e flange

[0062] 4 Polymer matrix

[0063] 5 cables

[0064] 6 seals

[0065] 7 ribs

[0066] 8Clamping sleeve

[0067] 8a junction section

[0068] 9 Leave blank

[0069] S1 First Press

[0070] S2 Second Press

[0071] O object.

Claims

1. A sensor device (S), comprising: A chip (1) with a sensor is arranged in a housing (3), wherein the chip (1) is arranged waterproof relative to the surrounding environment and no metal is arranged between the chip (1) and the object (O) to be sensed.

2. The sensor device (S) according to claim 1, wherein The chip (1) is a Hall element, an MR sensor, a GMR sensor or a TMR sensor, the Hall element is preferably a 2D or 3D Hall element, and the chip is preferably implemented as a rotation speed sensor, wherein a chip (1) further preferably includes at least two effective sensing areas.

3. The sensor device (S) according to claim 1 or 2, wherein The housing (3) has a cylindrical, prismatic or cuboid shape, and the chip (1) is arranged near an end side of the housing (3), in which a borehole (3a) is provided, the extension of which preferably corresponds at least to the extension of the chip (1).

4. The sensor device (S) according to claim 1 or 2, wherein The housing (3) is tubular.

5. The sensor device (S) according to claim 4, wherein A flange (3e) is provided on the end side of the housing (3), the chip (1) is arranged near the end side, and the flange extends in the direction of the center axis of the housing (3), wherein at least one hole (3d) is preferably provided in the flange (3e).

6. The sensor device (S) according to any one of claims 1 to 5, wherein: The chip (1) is arranged on a chip fixing section (2c) of a chip carrier (2), and the chip carrier (2) is arranged inside the housing (3).

7. The sensor device (S) according to claim 6, wherein The chip carrier (2) further comprises a first holding section (2a) and a second holding section (2b), wherein the first holding section (2a) is opposite a first opening (3b) in the housing (3), and the second holding section (2b) is opposite a second opening (3c) in the housing (3).

8. The sensor device (S) according to claim 6 or 7, wherein The housing (3) is filled with a polymer matrix (4), which surrounds the chip carrier (2).

9. The sensor device (S) according to claim 6 or 7, wherein The chip carrier (2) also has a plurality of ribs (7) adapted to abut against the inner side of the housing (3).

10. The sensor device (S) according to any one of claims 1 to 7, wherein The housing (3) consists of a thermosetting material which completely surrounds the chip (1) and preferably also completely surrounds the chip carrier (2).

11. Sensor device (S) according to any one of the preceding claims, wherein The sensor device (S) is axially movable relative to the object to be sensed.

12. Use of a sensor device (S) according to any of the preceding claims in a commercial vehicle.

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