WO2008148652A2

WO2008148652A2 - Quick mount sensor housing for sensors with air contact

Info

Publication number: WO2008148652A2
Application number: PCT/EP2008/056379
Authority: WO
Inventors: Stephan Henzler; Tobby Brandt; Boris Adam; Martin Schuerer
Original assignee: Robert Bosch Gmbh
Priority date: 2007-06-06
Filing date: 2008-05-23
Publication date: 2008-12-11
Also published as: DE102007026446A1; WO2008148652A3

Abstract

The invention relates to a quick mount, two-part sensor housing for sensors with air contact, comprising a first housing part (4), in which a sensor with at least one sensitive assembly (6) is arranged, a second housing part (12), which can be connected to the first housing part (4) using quick connection means that do not require tools to form a housing that surrounds the sensor, the second housing part (12) having at least one opening that allows the surrounding atmosphere to reach the sensor. One housing part (12) has a seal (19) which seals the sensor housing in the contact region between the two housing parts (4), (12) when said two housing parts (4), (12) are connected, and a seal (16) which, when the two housing parts (4), (12) are connected, divides the interior of the sensor housing into a region that is in contact with the surrounding atmosphere by means of the opening in the second housing part (12) and a region that is hermetically sealed in relation to the area surrounding the sensor.

Description

ROBERT BOSCH GMBH, 70442 Stuttgart

Quick-mount sensor housing for sensors with air contact

The invention relates to a quickly mountable sensor housing for sensors with air contact, in particular for moisture-hazardous installation locations.

State of the art

Chip-shaped sensors are used in various housing forms, for example for measuring chemical and / or physical parameters. For the functionality of certain sensors, it is necessary that the actual sensitive module of the sensor is in direct contact with the atmosphere surrounding the sensor. Complete hermetic encapsulation of the sensitive assembly is not possible in these cases. An example of such sensors are pressure sensors used in various industry-related and automotive applications. The direct access of the atmosphere surrounding the sensor to the sen- sitive module is often associated with the risk of various disturbing influences, in particular the ingress of moisture. For this reason, measures must be taken to reliably protect at least certain areas within a sensor housing from moisture and to limit the direct contact of the atmosphere surrounding the sensor to areas within the sensor housing to an absolutely necessary minimum.

It is therefore known to secure the interior of sensor housings by the use of various seals against external influences and to divide into areas that are exposed to environmental influences to varying degrees. The problem addressed and the invention will be explained in more detail below using the example of pressure sensors for use in motor vehicles, without being limited to such applications. A special field of application for such pressure sensors is their use in airbag systems. In these cases, pressure sensors are installed in side cavities of vehicles and used for the detection of the deformation of the body in a crash. Frequent installation locations for such pressure sensors can be found in

Area of the side doors. The interior volume of the side doors is subdivided into a so-called wet room and a so-called dry room, whereby pressure sensors are often mounted in the area of a partition wall between wet and dry room. The assembly is usually carried out in such a way that the sensor body is in the drying room and a hood or hood-shaped pressure inlet channel protrudes through an opening in the partition into the wet room. In order to maintain the functionality of the partition wall between wet and dry space, it is often necessary to close the holes required for mounting the pressure sensors by a seal between the sensor housing and, for example, acting as a partition separating plate during installation of the pressure sensors. In known applications, this closure is effected by a seal around the pressure inlet channel, which may consist of injected silicone or a sealing foam in the case of an adhesive connection. Tightness requirements, in particular with respect to the entry of water and other media, which are to be placed on the sensor housing itself, are met in known embodiments of multi-part sensor housing, for example, that the individual parts of the sensor housing are connected to each other by laser welding and sealed. Furthermore, an inner seal is often present, which in the assembled sensor housing whose interior in a sealed area for receiving electronic assemblies and an area for receiving the sensitive assembly subdivided, wherein the sensitive assembly is at least in partial contact with the surrounding atmosphere. The use of different sealing materials and the use of several process steps to complete such a sealed sensor housing are associated with considerable effort. This disadvantage is overcome by means of the invention.

Disclosure of the invention

The invention consists in a quickly mountable sensor housing for sensors with air contact. The rapid mounting in the sense of the invention is thereby ensured by the housing is made in two parts and can be the housing parts without tools connect with each other. The sensor housing according to the invention comprises a first housing part, in which a sensor with at least one sensitive assembly is located, a second housing part, which can be connected to the first housing part via connectable without tools connecting means, for example by snapping or pressing, to a housing to form, which encloses the sensor, wherein the second housing part has at least one opening, which allows the access of the surrounding atmosphere to the sensor. A housing part has a seal which, when the two housing parts are connected, ensures a sealing of the sensor housing in the contact region between the two housing parts. This housing part has a further seal, which in the connection of the two housing parts for a division of the interior of the sensor housing in an area which communicates via the opening in the second housing part with the surrounding atmosphere, and a region which hermetically opposite the sensor environment is complete.

Advantageous effects Advantageously, the sensor housing is designed as a housing for a pressure sensor, wherein the opening in the second housing part is formed by a nozzle-shaped pressure inlet channel. This makes it possible to mount sensors according to the invention in shielded areas behind corresponding openings. The concept of a quick assembly, it is also useful if the second housing part has fastening means with which an attachment of the sensor housing at predetermined installation locations is possible. Furthermore, it is advantageous if all for the operability of the

Sensor housing required seals are located on the second housing part. For versatility of a sensor housing according to the invention, it is advantageous if on the outside of the second housing part, a seal is arranged, which surrounds the opening which allows access of the surrounding atmosphere to the sensor. The connecting means for connecting the two housing parts advantageously comprise elastically deflectable latching elements and corresponding engagement structures. In particular, in a design of the two housing parts as plastic injection molded parts, such connecting means can be realized very easily. In this case, depending on the application, the connecting means can be designed in such a way that they can be detached from the outside or can not be loosened from the outside after assembly of the sensor housing according to the invention, which prevents unauthorized manipulation inside the sensor housing.

Manufacturing technology, it is also advantageous if all seals are made of silicone and are connected together, which allows their attachment in a single step of a two-component process.

Embodiments of the invention

In one embodiment, the invention is explained in detail. Show it: Fig.l a sensor housing with enclosed pressure sensor according to the prior art;

2 shows a housing part of a sensor housing according to the invention with fastening means;

3a a completely assembled sensor housing according to the invention with an enclosed pressure sensor; and

3b a further embodiment of a sensor housing according to the invention with enclosed pressure sensor.

All figures are executed as sectional views.

Fig.l shows a sensor housing with enclosed pressure sensor according to the prior art. The sensor is arranged on an opening in a partition wall 1, which is located inside a vehicle door, not shown, and separates the wet space 2 of the vehicle door from the dry space 3 of the vehicle door. The sensor housing is made of two parts, wherein a lower part 4 in the form of a trough serves to receive the actual sensor, in the present example the pressure sensor. The pressure sensor comprises a known capsule housing 5, which serves to encapsulate the actual sensitive assembly 6, in this case on a piezo-based basis. The sensitive assembly 6 is capable of converting pressure values of the adjacent atmosphere into electrical quantities, for example on a piezoresistive basis. For this reason, it is necessary that the sensitive assembly 6 is not completely encapsulated, but is in contact with the ambient atmosphere via a perforated cover structure 7. The sensitive module 6 is connected via bond connections 8 with laterally out of the capsule housing 5 pins 9 in connection. These pins 9 in turn lead to a circuit board 10 and corresponding locations of the connection, where, for example a solder joint between the pins 9 and continuing conductor tracks (not shown) may exist. In this case, the printed circuit board 10 can only receive the contacting of the actual sensor, in particular of the sensitive module 6, but can also record further electronics which can be used to control the sensor or for a first evaluation of signals obtained. For external contacting of the entire sensor arrangement at the installation site, the printed circuit board 10 is fixedly connected to the lower housing part 4 via contact and connection means 11 and can be incorporated into external circuits (not shown). The upper housing part 12 covers in the form of a cap from the lower housing part 4 and thus provides at least for a substantial protection of the housing interior from external mechanical influences. The upper housing part 12 has a pressure inlet channel 13, which projects in the form of a scoop through the opening in the partition wall 1 and thus allows the pressure prevailing in the interior of the wet space 2 of the vehicle door to continue directly to the sensitive assembly 6 of the pressure sensor , In order to further ensure the separation function of the partition 1 despite the opening required for mounting the sensor, the region of the opening is surrounded by an outer seal 14, which in the present case comprises a foam-filled region which connects the sensor to the partition wall 1 and Entry of liquids and mechanical contaminants through the opening in the partition wall 1 in the dry space 3 of the vehicle door prevented. The upper housing part 12 and the lower housing part 4 are connected to one another via a laser-welded region 15. At the same time, the laser-welded region 15 serves to seal the sensor housing, the sealing effect being ensured by means of a density test. Between the upper part of the housing 12 and the capsule housing 5 there is a further inner seal 16 which separates a region 17 immediately in front of the sensitive assembly 6, which must functionally communicate with the outside atmosphere, from the remaining interior space within the housing and for reliable protection the penetration of moisture in possibly occupied by electronics areas. This seal is according to the prior art in a two-component process, optionally silicone-based, before the mounting of the Gehäusetei- Ie 4 and 12 on the upper housing part 12 to be sprayed.

2 shows an upper housing part 12 of a sensor housing according to the invention with fastening means 18. This upper housing part 12 is equipped with a scoop acting as a pressure inlet duct 13 and made as an injection molded part from a plastic material, for example polypropylene, polyamide or PPT. To the upper housing part 12 different seals 14, 16, 19 are molded in a two-component process. An outer seal 14 is designed as a seal which runs around the pressure inlet duct 13 as a circumferential seal. A further usable as an inner seal 16 annular seal surrounds the leading into the housing interior opening of the pressure inlet channel 13 on the underside of the upper housing part 12. In the outer region of the upper housing part 12 elastically deflectable latching elements 20 are arranged, which can optionally interact positively with corresponding engagement structures of a housing part to be attached. Furthermore, the upper housing part 12 comprises positively locking guide elements in the form of an angled edge 21, which are intended to facilitate a joining of the upper housing part 12 with corresponding further housing parts. In the contact region between the upper housing part 12 and the further housing part to be optionally attached by a clip connection between the latching elements 20 and corresponding engagement structures, there is another one

Seal 19 is arranged, which ensures in the case of a complete assembly of the sensor housing for a sealing of the sensor housing relative to the housing environment. All three seals 14, 16, 19 are made of a uniform material and can therefore be applied in a single process step, in this case by injection molding of silicone. All three seals 14, 16, 19 are via injection channels in Kunststoffma- Material of the upper housing part 12 connected, which additionally provides a positional fixation. The upper housing part 12 further comprises fastening means 18, in the present case in the form of screws, with which it can be fixed at each desired installation locations prior to complete assembly of the sensor housing, wherein at the same time a pressing is effected by the fixation, which the unfolding of the sealing effect the outer seal 14 allows.

3a shows a fully assembled inventive sensor housing with an enclosed pressure sensor. An upper housing part 12 shown in FIG. 2 is fastened with fastening means 18 to a partition wall 1 in the interior of a vehicle door. A serving as a pressure inlet duct scoop protrudes through an opening in the partition wall 1 in the wet room 2 of the vehicle door, while the rest of the sensor housing is arranged in the drying room 3 of the vehicle door. The attachment of the upper housing part 12 is such that a mounted on the outside of the housing top 12 outer seal 14 is pressed firmly against the partition 1, whereby penetration of moisture and other media in the drying room 3 of the vehicle by the housing for the pressure inlet channel 13th required opening in the partition 1 is prevented. A designed for an inventive quick mounting days lower part 4 is designed trough-shaped and serves to receive the actual pressure sensor with the sensitive assembly 6, which is arranged in a known manner on a printed circuit board 10. The circuit board 10 itself is in turn connected via contact and connecting means 11 to the lower housing part 4. The lower housing part 4 has in its upper edge region on an outwardly facing peripheral edge 22, which serves for the latching elements 20 according to the invention on the upper housing part 12 as a corresponding engagement structure. Furthermore, the lower housing part 4 has a circumferential groove, into which engages the molded on the upper housing part 12 seal 19 during assembly of the two housing parts 4 ,. The joining of the Housing parts 4, 12 takes place only by inserting the lower housing part 4 in the upper housing part 12, wherein it comes in the form of a clip connection to the latching connection between the elastic locking elements 20 on the upper housing part 12 and the peripheral edge 22 on the lower housing part 4, if a short pressing is done. This form of Klips- connection allows an extremely fast assembly of the sensor housing according to the invention. When assembling the electronics assembly space is completely sealed, that is, both seal 19 and seal 16 are pressed, and only the area of the sensitive assembly 6 is still in contact with the surrounding atmosphere. The mounted on the upper housing part 12 seals 16, 19 are designed so that they provide sufficient restoring force, which ensures a sufficiently stable pressing of the lower housing part 4 against the locking elements 20 of the upper housing part 12 in the mounted state of the sensor housing. However, too firm a pressing of the inner seal 16 against the capsule housing 5, which surrounds the sensitive assembly 6, is also to be avoided in order to avoid deformation of the pins 9 connected to the printed circuit board 10 and to prevent overloading of the capsule housing 5. The dimensioning of the individual seals 14, 16, 19 and their reliable operation can be realized in a particularly simple manner in housing arrangements according to the invention, if the materials of the housing parts 4, 12 and the materials used for the seals 14, 16, 19, significantly different Have elasticity parameters, which is for example given when the housing parts 4, 12 are designed as injection molded parts, for example made of polypropylene, polyamide or PPT, while the seals 14, 16, 19 are made of highly elastic materials such as silicone. Overstressing the assembly of the housing parts 4, 12 by excessive deformation of the seals 16, 19 can be prevented when the upper edge of the lower housing part 4 is simultaneously designed or extended so that it when joining the two housing parts 4, 12 as Stop element is used, whereby a deep insertion of the lower housing part 4 is securely avoided in the upper housing part 12. In the present embodiment, the latching clip connection between the two housing parts 4, 12 designed so that they can be solved with the aid of simple tools by bending the locking elements 20 of the upper housing part 12 again, which may be advantageous if caused by malfunctioning a Replacement of such a equipped sensor should be required.

3b shows a further embodiment of a sensor housing according to the invention with enclosed pressure sensor. The essential difference from the exemplary embodiment shown in FIG. 3a is the design of the connection means which serve for the latching connection between the two housing parts 4, 12. The upper housing part 12 has in its outer region an angled edge 23, which serves only as a guide element when mating the two housing parts 4, 12. The upper edge of the lower housing part 4 has on its inside a peripheral edge 24, which corresponding locking elements 25 of the upper housing part 12 serves as an engagement structure, which are arranged within the contact area between the two Gehäuselemen- th at the upper housing part 12 and elastic in the inner region of the housing according to the invention can be deflected. The connection of the two housing parts 4, 12 takes place in this embodiment by simply inserting the lower housing part 4 in the upper housing part 12, wherein after engagement of the locking elements 25 formed in the formed by the inner peripheral edge 24 engagement structure simple release by application easier Tools is no longer possible. Such housing forms can be used in particular in security-relevant applications, where it can depend on protection of the sensors used from unauthorized access or unauthorized exchange.

Claims

claims

1. A two-part sensor housing for sensors with air contact, comprising a first housing part (4) in which a sensor is at least one sensitive assembly (6), a second housing part (12) with the first housing part (4) via Can be connected without tools connectable connecting means to form a housing which encloses the sensor, wherein the second housing part (12) has at least one opening which allows the access of the surrounding atmosphere to the sensor, and a housing part (12) has a seal ( 19), which ensures in the connection of the two housing parts (4), (12) for a sealing of the sensor housing in the contact area between the two housing parts (4), (12), and a seal

(16), which in the connection of the two housing parts (4), (12) for a division of the interior of the sensor housing in a region which communicates via the opening in the second housing part (12) with the surrounding atmosphere, and a Area that is hermetically sealed to the sensor environment ensures.

2. Sensor housing according to claim 1, characterized in that the housing is designed as a housing for a pressure sensor, wherein the opening in the second housing part

(12) is formed by a nozzle-shaped pressure inlet channel (13).

3. Sensor housing according to claim 1 or 2, characterized marked, that the second housing part (12) via fastening means (18), with which an attachment of the sensor housing at predetermined installation locations is possible.

4. Sensor housing according to one of claims 1 to 3, characterized in that the seals (16), (19) on the second housing part (12) are located.

5. Sensor housing according to one of claims 1 to 4, characterized in that on the outside of the second housing part (12) a seal (14) is arranged, which surrounds the opening which allows access of the surrounding atmosphere to the sensor.

6. Sensor housing according to one of claims 1 to 5, characterized in that the connecting means for connecting the two housing parts (4), (12) elastically deflectable latching elements (20), (25) and corresponding engagement structures (22), (24) ,

7. Sensor housing according to one of claims 1 to 6, characterized in that all seals (14), (16), (19) consist of silicone and are interconnected.

8. Sensor housing according to one of claims 1 to 7, characterized in that the two housing parts (4), (12) injection-molded parts made of plastic.

9. Sensor housing according to one of claims 1 to 8, characterized in that the connecting means (20), (22), which connect the two housing parts (4), (12) with each other, are to be solved from the outside.

10. Sensor housing according to one of claims 1 to 8, characterized in that the connecting means (24), (25), which connect the two housing parts (4), (12) with each other, are not to be solved from the outside.