SENSOR UNIT

Description

[0001] The present invention relates to a sensor unit comprising an electronics unit, a first housing part and a second housing part connected thereto, wherein the electronics unit is connected to the first housing part and projects into the interior, wherein a contact region is provided which penetrates the first housing part, wherein the electronics unit has at least one printed circuit board with at least two printed circuit board sections which are electrically conductively connected to one another.

[0002] Sensor units, especially position or inclination sensors, are used in harsh environments subject to strong environmental influences. They are also mounted on a wide variety of machine units, such as vehicles or production machines, and therefore require a correspondingly diverse design.

[0003] Sensor units are known from the prior art that have a contact area for electrical connection to the respective machine unit and a printed circuit board on or in a housing. The printed circuit board and contact area are usually connected to each other by means of insulated wires within the sensor unit's housing. To protect both the printed circuit board and the wires and contact area within the housing from external influences, the remaining volume of the housing is usually filled with a silicone or resin, for example. This reliably protects these components but makes subsequent modifications or modulations of the sensor unit's hardware more difficult. The printed circuit board can no longer be accessed without destruction or recycled.

[0004] US 4,864,156 discloses a proximity switch comprising a main housing, an intermediate plug housing and a sensor housing, wherein a circuit board is arranged in each housing and the circuit boards of the intermediate plug housing and the sensor housing are electrically conductively connected to one another and the circuit boards of the intermediate plug housing and the main housing are galvanically isolated from one another.

[0005] US 2003 / 0123242 A1 discloses a housing for a sensor, wherein the sensor housing has a coating on at least one side of the housing that is particularly resistant to external influences such as welding flashes. Furthermore, the housing has three housing parts that define an interior space in which an electronics unit is arranged.

[0006] US 2010 / 097050 A1 discloses a distance sensor.

[0007] The present invention therefore has the object of providing a sensor unit that is as easy to assemble, robust and easily transformable as possible.

[0008] This object is achieved by a sensor unit having an electronics unit, a first housing part and a second housing part connected thereto, wherein the first and second housing parts form an interior space between them and each have a housing part outer side directed away from this, wherein the electronics unit is connected to the first housing part and protrudes into the interior space, wherein a contact region is provided which penetrates the first housing part, wherein the electronics unit has at least one printed circuit board with at least two printed circuit board sections which are electrically conductively connected to one another, wherein a first printed circuit board section is arranged electrically conductively between the contact region and a second printed circuit board section.

[0009] The first and second housing parts are advantageously reversibly connected to one another in a force-fitting or form-fitting manner in order to make the interior easily accessible to a user in the event of a possible adjustment of the electronics unit. They are preferably made of a plastic with high strength, rigidity, and very good frictional resistance, advantageously ABS or PBT, in particular reinforced with glass fiber. According to the invention, the interior is designed such that, in addition to all components arranged in the interior, it also accommodates a gas, in particular ambient air or nitrogen, which prevents possible temperature fluctuations due to external influences that could potentially influence the measurement results. The use of a gas such as nitrogen to fill the interior prevents, according to the invention, the interior from igniting in the event of a malfunction of the sensor unit.The electronics unit is connected at least indirectly to the first housing part, in particular in a force-fitting and / or form-fitting manner. The contact region has at least one contact point and a contact frame, wherein the contact frame is integrally connected to the first housing part or alternatively in a force-fitting or form-fitting manner. According to the invention, electronic components are arranged on the first or second circuit board section depending on their use. According to the invention, the first and second circuit board sections can be formed in one piece or as two individual circuit boards, even spatially separated from one another. The advantage of using two individual and independently arranged circuit board sections is the flexible possibility of combining them with one another.Accordingly, all electronic components for one task are advantageously arranged on one circuit board section, and those for another task on another. This results in a modular principle, according to which the sensor unit can be optimally adapted to the respective requirements of the application. This enables a high degree of modularity and usability in a wide variety of applications with only minor modifications to a subsection of the electronic unit.The electrically conductive arrangement of the first circuit board section between the contact area and the second circuit board section contributes significantly to the aforementioned advantages of the invention, since this creates a standardized connection between the first and second circuit board sections and the circuit board sections can be connected and used with one another independently of the electronic components arranged thereon or an arranged contact area.

[0010] In an embodiment of the invention, it is provided that the first circuit board section transmits the electrical voltage and / or current applied to the contact area to the second circuit board section essentially unchanged in the operating state. In a particularly advantageous manner, the electronic components designed to contact the contact area and thus to connect it to the rest of the machine are arranged on the first circuit board section so that if the contact area changes, only the first circuit board section needs to be adapted. An arrangement of further electronic components on the first circuit board section, in particular lighting devices or optical displays, which function independently of the electronic components arranged on the second circuit board section, is also advantageous.In addition, electronic components such as fuses, in particular fine-wire fuses or 0 Ω resistors, are particularly advantageously arranged on the first circuit board section for flexible electrical contact between the at least one contact point and various areas of the first circuit board section. The electronic components required for the actual function of the sensor unit do not have to be rearranged, since the electromagnetic interference fields of the changing first circuit board section have only a very small or no influence due to the delimited arrangement. It is also possible to arrange the first circuit board section with a contact area suitable for a machine unit on a functionally different second circuit board section in order to obtain several differently acting sensor units for one slot.In other words, the advantage is twofold: firstly, a manufacturer of the sensors according to the invention can very easily adapt a sensor already designed for a machine should a change occur on the machine side; secondly, the manufacturer can arrange different sensors in one and the same housing with one and the same contact area and thus provide the machine manufacturer with different sensors to choose from without the machine manufacturer having to provide different contact options.

[0011] Advantageously, the first housing part is essentially plate-shaped in such a way that it covers a smaller portion of the part of the electronics unit that protrudes into the interior of the housing than the second housing part. Due to the essentially plate-shaped first housing part, all components are freely accessible during assembly of the electronics unit; reaching into a narrow interior space is not necessary. The plate-shaped design of the first housing part is primarily to be understood as meaning that the first housing part has its maximum cross-sectional area parallel to its main plane.

[0012] In a further development of the invention, the first housing part covers less than 30%, in particular less than 20%, preferably less than 10% of the part of the electronics unit that protrudes into the interior. Accordingly, all units arranged in the interior can be mounted on the first housing part and are also easily accessible. The second housing part closes off the interior, securely enclosing the electronics unit.

[0013] In an embodiment of the invention, it is provided that a circuit board section of the electronics unit is oriented substantially parallel to the main plane of the plate-shaped first housing part and that the electronics unit is fastened thereto at least indirectly to the first housing part and / or the two circuit board sections are arranged substantially orthogonal to one another. In a particularly advantageous manner, the contact frame of the contact area is arranged parallel and, depending on the nature of the contact points, close to the circuit board section arranged parallel to the main plane, and the at least one contact point is arranged substantially orthogonal to the contact frame and to the circuit board section arranged parallel to the main plane. Transmission lines, which would require additional receiving space and are also susceptible to damage from shocks or vibrations, are advantageously avoided.The fewer electrical contact points are necessary, the lower the risk of damage, destruction, or faulty manufacture of one of them. The firm connection between the circuit board section arranged parallel to the main plane and the contact area by directly soldering the at least one contact point onto the circuit board section arranged parallel to the main plane enables reliable positioning of the electronics unit through a positive and / or non-positive connection between the contact area and the first housing part, which minimizes damage to the electronics unit and the contact area. The at least one contact point is positively and / or non-positively connected to the contact frame, wherein the at least one contact point is in particular pressed onto the contact frame.The design of the contact frame as a separate component from the first housing part is advantageous because its flat main surface, which is aligned parallel to the first circuit board section, allows the at least one contact point to be mechanically soldered, in particular connected by wave soldering, to the first circuit board section in an arrangement predefined by the contact frame. With a one-piece design of the contact frame with the first housing part, the required dimensional compliance for the correct positioning of the at least one contact point is simplified due to the smaller number of tolerance ranges. In this embodiment, reliable positioning of the electronics unit is possible via a positive connection between the electronics unit and the first housing part. The orthogonal arrangement of the two circuit board sections is particularly advantageous because it creates a space-saving and modular electronics unit.

[0014] According to the invention, the sensor unit has a support structure attached to the first housing part and contacting the electronics unit, wherein the support structure is guided in a guide of the second housing part. The support structure is preferably detachably connected to the first housing part and / or the electronics unit. In particular, the connection is designed as a force-locking or form-locking connection, particularly preferably as a screw connection. The support structure is designed such that the most rigid possible connection is formed between it and the electronics unit for the direct transmission of occurring forces or vibrations. In this way, the electronics unit, in addition to the support structure, contributes to increasing the overall strength of the sensor unit.

[0015] In a further development of the invention, a molded seal is arranged between the first and second housing parts. The molded seal advantageously seals the interior from dirt, water, and dust; in particular, the interior thereby also has at least protection class IP 68. The molded seal is advantageously made of a rubber, in particular EPDM, NBR, FKM, or BR.

[0016] In an embodiment of the invention, the contact area is formed so that it is surrounded by a recess in the first housing part. The recess advantageously protects the contact area from damage. If the contact area is formed as one with many contact points protruding from the main plane, the recess has at least the length of the protruding contact points in order to protect them from damage. The recess advantageously has recess grooves. Configuring the recess grooves as recess webs is also advantageous in order to ensure secure insertion of the contact area into a machine unit and to minimize transverse forces occurring in the contact area, which could lead to damage.Preferably, the formation is designed in such a way that it prevents faulty contact between the contact area and a machine unit, in particular via differently designed formation guides or formation grooves.

[0017] Advantageously, the first housing part has at least one connection option for mechanically connecting the sensor unit to a machine unit. The use of a commercially available connection option is advantageous here. Particularly advantageously, the connection option is reversible, in particular designed as a snap hook, bayonet, or screw connection. Accordingly, the connection between the sensor unit and the machine unit is force-fitting and / or form-fitting. The connection option is advantageously designed as close as possible to or next to the contact area, in particular within the formation of the first housing part that borders the contact area. This ensures reliable contact with the contact area even in the event of vibrations or shocks caused by the machine unit or other environmental influences.

[0018] In a further development of the invention, the second housing part has an optical display, in particular an illuminant arranged on the circuit board and a light guide ending in the second housing part and / or an illuminant formed by a translucent section in the second housing part. The optical display enables a user to recognize, for example, correct contact between the machine unit and the contact area. Likewise, the optical display can advantageously output warning signals, for example in the event of overheating or incorrect contact. The output of a measured value directly on the sensor unit via the optical display is also possible. The illuminant is advantageously designed as at least one LED, although an LCD or a segment display can also be used.The light guide or the translucent section is advantageously connected to the second housing part in a form-fitting, force-fitting, or material-fitting manner, wherein the light guide has essentially the same mechanical properties, in particular similar strengths and similar thermal expansion coefficients, as the second housing part and therefore does not represent a weak point with regard to the stability of the second housing part. In a particularly advantageous manner, the light guide or the translucent section is overmolded by the second housing part, which forms, on the one hand, a form-fitting or material-fitting, non-detachable connection and, on the other hand, a sealing connection. The translucent section can also be designed as a through-opening, wherein the illuminant itself is connected to the second housing part in a form-fitting or force-fitting and sealing manner.

[0019] The invention will be explained in more detail below using an embodiment example with the aid of the figures, in which Fig. 1 a perspective view of the sensor unit, Fig. 2 a perspective exploded view of the sensor unit, Fig. 3 a section of the sensor unit in a side view and Fig. 4 show another section of the sensor unit in a different side view.

[0020] Fig. 1 shows a perspective view of the sensor unit 1, wherein the sensor unit 1 has a first housing part 3 and a second housing part 4, wherein the two housing parts 3, 4 are non-positively connected to one another by means of two screws 20. The first and the second housing part 3, 4 each have a housing part outer side 6, wherein the housing part outer side 6 of the first housing part 3 is designed such that a contact region 7 is arranged thereon, which is bordered by a formation 15 of the first housing part 3. The formation 15 has a length extending orthogonally away from a main plane 10, which is longer than the length of contact points 21 of the contact region 7 in order to protect them from impacts and other external influences.Furthermore, the formation 15 has a formation opening 23 on each of two opposing formation walls 22, forming a connection option 16 for mechanically connecting the sensor unit 1 to a machine unit (not shown). The formation openings 23 can be penetrated in particular by means of a snap hook (not shown) arranged on the machine side in order to form a detachable, positive-locking connection between the sensor unit 1 and the machine unit. The connection option 16 is further offset from an inner formation surface 24 of the formation 15 in such a way that a formation guide 25a is formed for attaching the sensor unit 1 to the machine unit. In addition, the formation 15 has two formation grooves 26 on its inner formation surface 24, which have a different width.The molding grooves 26 are designed as additional molding guides 25b and to prevent improper attachment of the sensor unit 1 to the machine unit. The second housing part 4 has a light guide 19 on its outer side 6, which is positively connected to the second housing part 4. The light guide 19 is overmolded by the second housing part 4.

[0021] Fig. 2 shows a perspective exploded view of the sensor unit 1, wherein an electronics unit 2 with a first and a second circuit board section 9a, 9b is arranged in an interior space 5 (not shown) between the first and second housing parts 3, 4, wherein the circuit board sections 9a, 9b are each designed as individual circuit boards 8a, 8b according to the invention. The first circuit board 8a is arranged orthogonally to the second circuit board 8b, wherein the first circuit board 8a is arranged parallel to the main plane 10 and contacts the contact area 7, wherein the contact area 7 is plugged onto the first circuit board 8a by means of contact points 21 and is machine-soldered onto the first circuit board 8a.According to the invention, a first transmission unit 27a is also arranged on the first circuit board 8a, wherein the first transmission unit 27a accommodates a second transmission unit 27b arranged on the second circuit board 8b and thus forms the electrically conductive connection between the first and second circuit boards 8a, 8b. A support structure 11 is formed between the first and second circuit boards 8a, 8b, which is connected to the first and second circuit boards 8a, 8b via a screw connection using two screws 20 each. The two screws 20 for connecting the support structure 11 to the first circuit board 8a are screwed into the first housing part 3, thereby clamping the first circuit board 8a between the latter and the support structure 11.The first housing part 3 has lugs 28 that are received in support structure grooves 29 to ensure reliable positioning of the first circuit board 8a and the support structure 11 on the first housing part 3. The support structure 11 has a frame / truss construction to absorb any stresses or forces that occur and to transmit them as directly as possible to the circuit boards 8a, 8b. According to the invention, the support structure 11 has guide webs 30 that are guided in a non-visible guide 12 of the second housing part 4, wherein the guide 12 is designed as a groove. The width of the guide web 30 increases in the direction of the main plane 10. The non-visible guide 12 is tapered in width pointing away from the main plane 10, so that a force-fitting connection, in particular a clamping connection, is formed between the second housing part 4 and the support structure 11.A reliable hold between the second housing part 4 and the support structure 11, and thus also between the electronics unit 2 and the second housing part 4, is thus ensured. A molded seal 13 is formed between the first and second housing parts 3, 4. The molded seal 13 further comprises a molded seal nose 40, which can be received in a molded seal recess 41 in the second housing part 4. This arrangement advantageously makes it possible to detect, even in the installed state, whether the molded seal 13 is arranged between the first and second housing parts 3, 4. On an outer side 6 of the second housing part 4, which is formed opposite the outer side 6 of the housing part on which the invisible light guide 19 is arranged, the second housing part 4 has a pressure equalization opening 31, which is surrounded on one side by a pressure equalization membrane 32 in the operating state.The second housing part 4 further comprises two offset sections 33, wherein section openings 34 are formed on the offset sections 33, the axes of which are arranged parallel to the main plane 10 and which, in turn, have section webs 35 running parallel to the main plane 10 for each receiving a sleeve 36. The sleeves 36 can be clamped within the section openings 34 by means of the section webs 35 and are designed to accommodate a screw and the associated clamping force. Accordingly, the second housing part 4, which is made of a plastic, is protected from damage or even destruction by clamping forces.

[0022] Fig. 3 shows a section of the sensor unit 1 in a side view, wherein the guide webs 30 of the support structure 11 are accommodated within the guides 12 of the second housing part 4. The guide 12 is designed as a tapered groove extending into the image plane. The light guide 19 is designed such that it projects from the housing part outer side 6 into the interior 5, wherein the distance between the light guide 19 and a light source 18 arranged on the second circuit board 8b is as small as possible in order to prevent unwanted scattering of the light from the light source 18 and damage to the circuit boards 8a, 8b and the light source 18 during assembly and disassembly. The light source 18 is designed as an LED, which has the states red and green, wherein red represents a fault and green represents fault-free functionality of the sensor unit 1. The second circuit board 8b is firmly attached to the support structure 11 by means of screws 20.Opposite the light guide 19, a pressure equalization opening 31 is arranged on the second housing part 4.

[0023] Fig. 4shows a further section of the sensor unit 1 in a different side view, wherein the first housing part 3 is penetrated by the contact area 7, which has contact points 21 in the form of pins that penetrate the first circuit board 8a, as well as a contact frame 37. The contact frame 37 is arranged between the contact points 21 and the first housing part 3, rests positively on the first housing part 3 and is pressed together with the contact points 21. The contact frame 37 is advantageously made of a material comparable to the first housing part 3 in order to transmit external stresses, forces or vibrations acting on the first housing part 3 directly to the electronics unit 2. The molded seal 13 rests positively on the second housing part 4 around the first circuit board 8a, wherein the second housing part 4 has a molded seal web 39 corresponding to a molded seal groove 38 of the molded seal 13 for the form fit.Contact between the first and second circuit boards 8a, 8b is prevented by the support structure 11, so that the first and second circuit boards 8a, 8b are electrically connected to one another only via the first and second transmission units 27a, 27b. The first and second circuit boards 8a and 8b are located to the left of the main plane 10, which is defined by a contact surface between the first and second housing parts 3, 4. The first and second housing parts 3, 4 are designed on their contact surface such that, adjacent to the contact surface, they accommodate the molded seal 13 between them in such a way that over-pressing and thus damage or even destruction of the molded seal 13 is prevented, but functional pressing of the molded seal 13 to form a reliable seal of the interior 5 is possible. The first housing part 3 does not cover the part of the electronics unit 2 protruding into the interior 5. LIST OF REFERENCE SYMBOLS

[0024] 1Sensor unit 2Electronics unit 3First housing part 4Second housing part 5Interior 6Housing part exterior 7Contact area 8, 8a, 8bPrinted circuit board 9, 9a, 9bPrinted circuit board section 10Main plane 11Support structure 12Guide 13Molded seal 15Shaping 16Connection option 17Optical indicator 18Light source 19Light guide 20Screw 21Contact point 22Shaping wall 23Shaping opening 24Shaping inner surface 25, 25a, 25bShaping guide 26Shaping groove 27, 27a, 27bTransmission unit 28Nose 29Support structure groove 30Guide web 31Pressure equalization opening 32Pressure equalization membrane 33Stepped section 34Section opening 35Section webs 36Sleeve 37Contact frame 38Molded seal groove 39Molded seal web 40Molded seal nose 41Molded seal recess

Claims

1. Sensor unit (1) comprising an electronics unit (2), a first housing part (3) and a second housing part (4) connected thereto, the first and the second housing part (3, 4) forming therebetween an interior (5) and each having a housing part outer side (6) directed away from said interior, the electronics unit (2) being connected to the first housing part (3) and projecting into the interior (5), a contact region (7) that passes through the first housing part (3) being provided, the electronics unit (2) having at least one printed circuit board (8) which has at least two printed circuit board portions (9) that are electrically conductively connected to one another, the at least two printed circuit board portions (9a, 9b) each being designed as individual printed circuit boards (8a, 8b), a first printed circuit board portion (9a) being arranged electrically conductively between the contact region (7) and a second printed circuit board portion (9b), a first transmission unit (27a) being arranged on the first printed circuit board (8a), the first transmission unit (27a) accommodating a second transmission unit (27b) arranged on the second printed circuit board (8b) and thus forming the electrically conductive connection between the first and the second printed circuit board (8a, 8b), characterized in that the sensor unit (1) has a support structure (11) which is fastened to the first housing part (3) and contacts the electronics unit (2), the support structure (11) having guide projections (30) which are guided in a guide (12) of the second housing part (4), the guide (12) being designed as a groove, the width of the guide projection (30) increasing in the direction of a main plane (10) of the first housing part (3) and the guide (12) being tapered in its width, pointing away from the main plane (10), such that clamping is established between the second housing part (4) and the support structure (11).

2. Sensor unit (1) according to claim 1, characterized in that the first printed circuit board portion (9a), in the operating state, transmits electrical voltage and / or current intensity applied at the contact region (7) to the second printed circuit board portion (9b) in a substantially unchanged manner.

3. Sensor unit (1) according to claim 1 or 2, characterized in that the first housing part (3) is designed to be substantially planar in such a way that it covers a smaller part of the part of the electronics unit (2) projecting into the interior (5) than the second housing part (4).

4. Sensor unit (1) according to claim 1, 2 or 3, characterized in that the first housing part (3) covers less than 30%, in particular less than 20%, preferably less than 10%, of the part of the electronics unit (2) projecting into the interior (5).

5. Sensor unit (1) according to claim 3, characterized in that a printed circuit board portion (9) of the electronics unit (2) is oriented substantially in parallel with the main plane (10) of the planar first housing part (3) and is fastened therewith to the first housing part (3), and / or the two printed circuit board portions (9a, 9b) are arranged substantially orthogonally to one another.

6. Sensor unit (1) according to one of the preceding claims, characterized in that a molded seal (13) is arranged between the first and the second housing part (3, 4).

7. Sensor unit (1) according to one of the preceding claims, characterized in that the contact region (7) is designed to be surrounded by a formation (15) of the first housing part (3).

8. Sensor unit (1) according to one of the preceding claims, characterized in that the first housing part (3) has at least one connection option (16) for mechanically connecting the sensor unit (1) to a machine unit.

9. Sensor unit (1) according to one of the preceding claims, characterized in that the second housing part (4) has a visual display (17), in particular a by a lighting means (18) arranged on the printed circuit board (8) and a light guide (19) ending in the second housing part (4) and / or a lighting means (18) formed by a light-permeable portion in the second housing part (4).