Active sensor with a truck-specific housing

Abstract

The present invention relates to a sensor device (S) for a commercial vehicle, in particular a speed sensor. The sensor device (S) has: a chip (1) with a sensor, which is provided in a housing (3), wherein the chip (1) is arranged in a watertight manner with respect to the environment, and no metal is provided between the chip (1) and the object (O) to be sensed. Interfering eddy currents can therefore be avoided and a long service life of the sensor can be achieved by the water-tightness.

Description

[0001] DESCRIPTION

[0002] Active sensor with truck-specific housing

[0003] The present application deals with a sensor in a truck-specific housing, in particular an active speed sensor.

[0004] In commercial vehicles, wheel speed sensors are used in particular for anti-lock braking systems (ABS), electronic braking systems (EBS), electronic stability programs (ESP) and autonomous driving.

[0005] For example, in the anti-lock braking system (ABS), the rotational speed of each wheel is measured. Commercial vehicles, in particular, use passive, coil-based speed sensors; these have no other functions. In trucks, passive speed sensors are attached using a clamp sleeve. However, especially in passenger vehicles, there are also so-called active speed sensors (based on Hall technology or MR technology). These sensors are installed facing a pole wheel or encoder wheel.

[0006] Active speed sensors offer several advantages, as they can integrate multiple functions. Such sensors also need to be installed appropriately and secured at their location.

[0007] In the prior art, for example, document DE 102004 028 818 A1 is known. This document discloses a speed sensor with a housing that can be inserted into a socket, with the sensor located inside the housing. Contact elements connected to the sensor connect the sensor to an outer side of the housing. The housing can be inserted into the socket accordingly.

[0008] In a commercial vehicle, different wiring paths are required than in a passenger vehicle, as a commercial vehicle is generally much larger. Therefore, special precautions must be taken with regard to EMC (electromagnetic compatibility). It is therefore an object of the present invention to provide a speed sensor that is axially displaceable and offers maximum robustness with regard to electromagnetic compatibility. This object is achieved by a sensor device according to claim 1. Further advantageous embodiments of the present invention are the subject of the dependent claims.

[0009] A sensor device according to the invention comprises: a chip with a sensor which is provided in a housing, wherein the chip is arranged in a watertight manner with respect to the environment, and no metal is provided between the chip and the object to be sensed.

[0010] This ensures extreme mechanical robustness and, furthermore, maximum robustness with regard to electromagnetic compatibility, since there is no interfering metal near the chip (or in the direct path between the sensor and the object to be sensed). Furthermore, damage to the chip can be avoided.

[0011] Preferably, the chip is a Hall element, more preferably a 2D / 3D Hall element, an R sensor, a GMR sensor or a TMR sensor, which is preferably listed as a speed sensor.

[0012] Such sensors are used particularly in commercial vehicles. Furthermore, a chip preferably comprises at least two active sensing areas. Three active sensing areas can also be provided, for example, if the rotational speed and direction are to be detected.

[0013] The housing can be made of metal. It can also include ceramic or compound materials.

[0014] The housing preferably has a cylindrical, prism-shaped, or cuboidal shape, and the chip is arranged near a front side of the housing. A bore is provided in the front side, the dimension of which preferably corresponds at least to the dimension of the chip. This ensures that there is no metal between the chip and the object to be sensed (e.g., a magnet wheel or encoder wheel), which could interfere with electromagnetic detection.

[0015] This is intended to ensure that there is no metal between the active sensing areas of the chip and the object to be sensed.

[0016] Furthermore, the housing is preferably tubular—this eliminates the need for end faces, and there is no metal between the chip and the object to be sensed (e.g., a magnet wheel or encoder wheel). Furthermore, the manufacturing costs of a tube (only a tubular casing) are significantly lower than those of a sleeve. This also improves electromagnetic compatibility, as eddy currents in the area of ​​the sensor chip can be reduced.

[0017] Preferably, a collar is provided on the end face of the housing near which the chip is arranged, extending in the direction of the center axis of the housing. Preferably, at least one hole is provided in the collar. This hole allows water to drain out of the housing, should it accumulate on the inside of the housing, and prevent it from reaching the chip.

[0018] Further preferably, the chip is provided on a fixing section of a chip carrier, and the chip carrier is arranged within the housing. The chip carrier further preferably comprises a first holding section and a second holding section, wherein the first holding section is opposite a first opening in the housing, and the second holding section is opposite a second opening in the housing. Thus, the holding sections can be held in place with appropriate stamps (external holding devices for the overmolding process).

[0019] Further preferably, the housing is filled with a polymer matrix that surrounds the chip carrier. This allows the chip carrier to be held in the housing when the stamping dies are present, and then the overmolding can be performed. Further preferably, the chip carrier has a plurality of ribs that are adapted to fit tightly against the inside of the housing. Such ribs can also be designed as melt ribs, which fix the chip carrier to the housing and seal it, so that no water can move within the housing and, in particular, cannot penetrate into the area where the chip is provided.

[0020] In a further embodiment, the housing is made of a thermosetting material that completely surrounds the chip, and preferably also the chip carrier. In such an embodiment, no sleeve or tube is required to externally delimit the sensor device.

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

[0022] Preferably, the sensor device is used in a commercial vehicle.

[0023] In the following, preferred embodiments of the present invention are described in more detail with reference to the accompanying figures.

[0024] Fig. 1 shows a sensor device according to the prior art, Fig. 1a) shows a sectional view and Fig. 1b) shows an isometric view.

[0025] Fig. 2 shows a first embodiment according to the present invention Fig.

[0026] Fig. 2 a) shows a sectional view. Fig. 2 b) and 2 c) show detailed views of one side of the sensor device, Fig. 2 d) shows an isometric view of the sensor device, and Fig. 2 e) shows a front view of the sensor device.

[0027] Fig. 3 shows a second embodiment of the sensor device according to the invention in a sectional view. Fig. 4 shows a third embodiment of the present invention. Fig. 4 a) shows a sectional view, and Fig. 4 b) shows an isometric view.

[0028] Fig. 5 shows a detailed view during the manufacture of the sensor device (according to the first, second, or third embodiment), in particular during the overmolding of the chip carrier with a matrix. Figs. 5 b) and 5 c) show corresponding partial views of the respective first holding section and second holding section.

[0029] Fig. 6 shows a fifth embodiment of the present invention. Fig. 6 a) shows, in particular, the chip carrier. Fig. 6 b) shows a corresponding isometric view.

[0030] Fig. 7 shows a fifth embodiment of the present invention. Fig. 7 a) shows an isometric view, Fig. 7 b) shows a front view.

[0031] In Fig. 1 a) a sensor device S according to the prior art is shown in sectional view.

[0032] A chip 1 is provided on a chip carrier 2, more precisely on a chip fixing section 2c. The chip carrier 2 further comprises a first holding section 2a and a second holding section 2b. The chip carrier 2 including the chip 1 is provided in a housing 3, which here is designed as a sleeve - i.e. has a cylindrical shape, with a corresponding casing and cover. Furthermore, a seal 6 is provided on the outside of the housing 3. On the side facing away from the chip 1, a cable 5 is provided which connects the housing 3 to the environment. The chip carrier 2 is fixed within the housing 3, which is overmolded with a polymer matrix 4. Opposite the first holding section 2a, a first opening 3b is provided in the housing 3, and correspondingly, opposite the second holding section 2b, a second opening 3c is provided in the housing.

[0033] Fig. 1 b) shows an isometric view of a sensor device S according to the prior art. Here, it can be seen that the cable 5 exits the housing 3, and first openings 3b are also provided in the housing. The first openings 3b are not shown here.

[0034] Fig. 2 a) shows a view similar to Fig. 1, but according to a first embodiment of the present invention. Here, it can be seen that a large bore 3a is provided in the end face of the housing 3, so that no metal is present between the area over which the chip 1 extends and an object 0 to be sensed (not shown here). All other sections are exactly the same as in Fig. 1 a).

[0035] Fig. 2 b) shows a detailed view, also revealing the bore 3a. Furthermore, a corresponding collar 3e is provided, which extends slightly in the direction of the center axis of the housing 3. Here, this collar has an L-shape. Fig. 2 c) also shows a collar 3e, but this one has an LI shape. Fig. 2 d) shows a symmetrical view, again showing the housing 3 and the first openings 3b. The bore 3a is clearly visible on the front side, and several holes 3d are provided on the collar 3e. These serve to ensure that, should liquid penetrate into the interior of the housing 3, it can then easily flow out again. At the same time, however, the polymer matrix 4 (not shown here) ensures that the chip is absolutely watertight and sealed from the environment. In Fig.2 e) shows a view from the front, here the opening 3a with the corresponding holes 3d in the collar 3e is also shown.

[0036] Fig. 3 shows a second embodiment of the present invention. This view is similar to Fig. 2 a), with the difference that here two seals 6 are arranged on the outside of the housing 3—one on each side of the housing 3. Here, too, a sleeve shape is present, ie, a cylindrical shell and a cover.

[0037] Fig. 4 a) shows a third embodiment of the present invention. Here, it is shown that the housing 3 is designed as a tube—that is, it has no end face or cover, but only a lateral surface. Here, it is again evident that the first holding section 2a and the second holding section 2b are opposite a corresponding first opening 3b and a corresponding second opening 3c in the housing 3.

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

[0039] Fig. 5 a) shows a state during the manufacturing process of the sensor device. In particular, it is disclosed here that a first die S1 can be inserted through the first opening 3b, and a second die S2 through the second opening 3c. These dies hold the chip carrier 2 (the first die S1 holds the first holding section 2a, the second die S2 holds the second holding section 2b) while the overmolding with the polymer matrix 4 takes place.

[0040] Fig. 5 b) shows two states during the overmolding process, showing how the second holding section 2b is held from several sides by the second punch S2. The left-hand view shows that the punches S1 fix a star-shaped section of the second holding section 2b, and then the corresponding area is recessed from the polymer matrix. The right-hand illustration shows a later state, where the second punches S2 have moved slightly away from the second holding section 2b, so that the immediate area surrounding the second holding section 2b is overmolding. This ensures that there is no hole within the polymer matrix 4, but rather that the polymer matrix 4 completely seals the chip element 1 (not shown here) from the environment in a watertight manner.

[0041] Fig. 5 c) shows how the first holding section 2a is held by first dies S1. No two-stage overmolding is performed here, as shown in Fig. 5 b). Holes can indeed be created here, but as can be seen from Fig. 5 a), these are far away from the sensor element 1.

[0042] Fig. 6 a) shows a fourth embodiment of the present invention. Only one chip carrier 2 is shown here, again correspondingly with a first holding section 2a and a second holding section 2b.

[0043] A plurality of ribs 7 are provided along the chip carrier 2. These ribs can be designed, for example, as melting ribs (which, for example, melt upon heating, thus achieving a sealing effect). These ribs can provide a watertight seal between the chip carrier 2 and the housing 3 (not shown here), so that no water can reach the chip 1 (corresponding to the chip fixing section 2c).

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

[0045] Fig. 7 a) shows a fifth embodiment of the present invention in an isometric view. Here, a housing 3 is again provided, and a cable 5 exits this accordingly. Here, however, the chip 1 and the chip carrier 2 (not shown here) are completely surrounded by a thermosetting housing 3, i.e. the chip 1 and the chip carrier 2 (not shown here) are correspondingly over-molded with a thermosetting plastic. The housing 3 has two recesses 9, into which corresponding engagement sections 8 of a clamping sleeve can engage, making the housing correspondingly more robust. Fig. 7 b) shows a view from the front, here again the position of the two engagement sections 8a of the clamping sleeve 8 in the corresponding recess 9 is shown in more detail.

[0046] The present invention is not limited to the above-mentioned embodiments.

[0047] Overmolding can also be done with other materials, such as rubber, caoutchouc or other waterproofing materials.

[0048] LIST OF REFERENCE SYMBOLS

[0049] S sensor device

[0050] 1 chip

[0051] 2 chip carriers

[0052] 2a first stopping section

[0053] 2b second holding section

[0054] 2c Chip fixing section

[0055] 3 housings

[0056] 3a Borehole

[0057] 3b first opening

[0058] 3c second opening

[0059] 3D hole

[0060] 3rd collar

[0061] 4 Polymer matrix

[0062] 5 cables

[0063] 6 Seal

[0064] 7th rib

[0065] 8 clamping sleeve

[0066] 8a intervention section

[0067] 9 Recess

[0068] 51 first stamp

[0069] 52 second stamp

[0070] 0 object

Claims

PATENT CLAIMS 1 . Sensor device (S), comprising: a chip (1) with a sensor which is provided in a housing (3), wherein the chip (1) is arranged in a watertight manner with respect to the environment, and no metal is provided between the chip (1) and the object (0) to be sensed.

2. Sensor device (S) according to claim 1, wherein the chip (1) is a Hall element, preferably a 2D or 3D Hall element, an MR sensor, a GMR sensor or a TMR sensor, which is preferably designed as a speed sensor, wherein a chip (1) further preferably comprises at least two active sensing areas.

3. Sensor device (S) according to one of claims 1 or 2, wherein the housing (3) has a cylindrical shape, prism shape or cuboid shape, and the chip (1) is arranged near an end face of the housing (3), in which a bore (3a) is provided, the extent of which preferably corresponds at least to the extent of the chip (1).

4. Sensor device (S) according to one of claims 1 or 2, wherein the housing (3) is tubular.

5. Sensor device (S) according to claim 4, wherein on the end face of the housing (3), near which the chip (1) is arranged, a collar (3e) is provided which extends in the direction of the central axis of the housing (3), wherein preferably at least one hole (3d) is provided in the collar (3e).

6. Sensor device (S) according to one of claims 1 to 5, wherein the chip (1) is provided on a chip fixing portion (2c) of a chip carrier (2), and the chip carrier (2) is arranged within the housing (3).

7. Sensor device (S) according to claim 6, wherein the chip carrier (2) further comprises a first holding portion (2a) and a second holding portion (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. 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. Sensor device (S) according to claim 6 or 7, wherein the chip carrier (2) further comprises a plurality of ribs (7) adapted to fit tightly against the inside of the housing (3).

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

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

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

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