Ultrasonic transceiver and its manufacturing method

Abstract

An ultrasonic transceiver (1) for a vehicle includes a plastic housing (2), an ultrasonic diaphragm (3), an acoustic transducer element (4) for exciting and detecting the vibration of the ultrasonic diaphragm (3), and a conductive contact element (6) disposed inside the plastic housing (2) for making electrical contact with the acoustic transducer element (4), wherein the plastic housing (2) and the contact element (6) are directly and form-fittedly connected to each other by the filling of at least one plastic element (8) integrally formed with the plastic housing (2).

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of ultrasonic sensors for vehicles and in particular to an ultrasonic transceiver for a vehicle and a method for producing the same. BACKGROUND

[0002] It is known that an ultrasonic transceiver has a housing, an ultrasonic membrane assembled at an opening of the housing, a transducer element bonded to the ultrasonic membrane, and a printed circuit board having electronics for activating the transducer element, which are in contact with the transducer element by means of a contact element.

[0003] Such an ultrasonic transceiver can be used to measure the distance to obstacles in the vehicle's surroundings using the pulse-echo method. The ultrasonic membrane, which is excited by the transducer element, emits energy in the form of ultrasonic signals. Then, the transducer element detects vibrations of the ultrasonic membrane, which are caused by echo signals returning from the vehicle's surroundings. The distance to the obstacle is determined by means of the signal propagation delay. Such a measurement is used, for example, by a parking assistance system of a vehicle.

[0004] Some of the emitted ultrasonic energy is radiated into the interior of the housing and stimulates the latter to produce unwanted structural vibrations, which lead to the detection of false or ghost echoes. Therefore, no useful measurement is possible for the duration of the decay time of the structural vibrations. Thus, the distance measurement can have a blind range at high rangefinder ranges.

[0005] In order to improve the structural dynamics of the ultrasonic transceiver, the electrical contact element can be overmoulded in the plastic housing. This requires complex injection moulding tools and makes access more difficult when the contact element is in electrical contact with the transducer element. The contact element can also be press-fitted in the housing. In this technique, further measures, such as a fully encapsulated housing, are required to increase the adaptability.

[0006] DE 10 2005 009 620 A1, DE 10 2017 109 159 A1 and US 2018 / 056901 A1 are examples of ultrasonic transceivers in the prior art. SUMMARY

[0007] Against this background, it is an object of the present invention to provide an improved ultrasonic transceiver and an improved method for producing the same.

[0008] According to a first aspect, an ultrasonic transceiver for a vehicle is proposed, having a plastic housing, an ultrasonic membrane, a transducer element for exciting vibrations and detecting vibrations of the ultrasonic membrane, and an electrically conductive contact element arranged inside the plastic housing for electrically contacting the transducer element, wherein the plastic housing and the contact element are directly and form-fittingly connected to each other by means of a heat staking of at least one plastic element formed integrally with the plastic housing.

[0009] The proposed ultrasonic transducer can advantageously have an improved structural dynamics. By the proposed type of connection of the contact element to the thermally riveted plastic housing (plastic element formed integrally with the plastic housing) in the region of the contact element, the contact element and the plastic housing can advantageously form a rigid unit which can better absorb vibration energy. Tests carried out by the inventors have shown that a shorter structural vibration decay time can be achieved, thus a shorter distance measurement blind time period. Furthermore, the service life and long-term stability of the decay time of the ultrasonic transducer can be increased. Furthermore, it can be advantageously possible to completely or partially dispense with encapsulating the plastic housing with a silicone foam or the like, while still achieving the above-mentioned advantages, wherein the mass of the ultrasonic transducer can be reduced, which leads to a further shortening of the decay time and an improved structural dynamics of the ultrasonic transducer.

[0010] The vehicle can in particular be a motor vehicle, for example a passenger car or a truck. The vehicle can in particular be equipped with a driver assistance system and / or a parking assistance system.

[0011] Thermal riveting is understood in particular to mean thermoplastic riveting. Thermal riveting is understood in particular to mean a process in which a section of the plastic element is thermoplastically deformed with the supply of heat, as a result of which an at least form-fitting, preferably frictional, connection is produced between the plastic housing and the deformed plastic element and the contact element under the action of a riveting device. The riveting device can be a punch. Another example of a riveting device is laser radiation or infrared radiation.

[0012] The plastic element is formed integrally with the plastic housing. In particular, the plastic element and the plastic housing are formed as a continuous element by casting, for example injection molding in one work step. The plastic element is in particular arranged inside the plastic housing. The plastic element can be considered a section of the plastic housing. In the present case, it can in particular be referred to as "thermally riveted plastic housing" or "section of a thermally riveted plastic housing", whereby "thermal riveting of the plastic element" or a section thereof can be meant.

[0013] The plastic element can be, for example, a inwardly protruding protrusion of the plastic housing, for example a plastic dome or the like.

[0014] In the present case, "form-fitting connection" is understood to mean a connection which interlocks or engages from behind by two connection partners.

[0015] In the present case, "direct connection" is understood to mean that no further connection element (for example a screw or the like) is used for the connection in addition to the connection partners.

[0016] In particular, the plastic housing (one connection partner) and the contact element (the other connection partner) are directly connected by the suitably heat staked plastic housing (the thus integrally formed plastic element).

[0017] The transducer element can in particular be a piezoelectric element or an ultrasonic transducer. The transducer element can be glued to the ultrasonic membrane, welded to the ultrasonic membrane or connected to the ultrasonic membrane in a different way.

[0018] The "contact element for electrically contacting the transducer element" is to be understood in particular as meaning that an electrical signal can be applied to the contact element in order to cause the transducer element to excite the ultrasonic membrane to vibrate, thereby emitting an ultrasonic signal, and / or an electrical signal indicating the vibration of the ultrasonic membrane detected by the transducer element can be received at the contact element, thereby detecting a reflected echo signal. The contact element can be in direct or indirect contact with the transducer element. In particular, indirect contact with the transducer element is preferred for reasons of acoustic decoupling. The contact element can comprise one or more segments which can be formed as contact pins, electrically conductive elements, electrically conductive tracks or the like. The contact element can in particular be a metallic element.

[0019] In this case, the words "one" and "an" are not limited to the interpretation "exactly one" unless otherwise stated, and can also include the meaning "multiple". In particular, it is to be understood that two or more contact elements can also be provided in the plastic housing, each of which can be connected to the plastic housing in the same way as described for "one" contact element.

[0020] According to one embodiment, a constraint exists between the plastic housing and the contact element.

[0021] The connection between the plastic housing and the contact element produced by heat staking of the at least one plastic element is therefore preferably not only form-fitting but also frictional. In particular, a normal force acts on the surfaces of the plastic housing, the plastic element and the contact element to be connected to one another. In particular, the connection between the plastic housing and the contact element is statically overdetermined. The strength of the constraint can be chosen taking into account vibrations expected during operation caused by emitted and received ultrasonic signals, driving movements of the vehicle or the like. It is possible to check whether a suitable constraint exists by means of a pull-off test. The quality of the heat staking can be controlled by parameters of the heat staking machine. It is also possible to optically check the quality of the heat staking with a camera.

[0022] According to one embodiment, the contact element is a rigid element and the electrical contact between the contact element and the transducer element is established via a flexible intermediate element.

[0023] This means that, according to the present embodiment, the contact element indirectly contacts the transducer element via the intermediate element. The flexible intermediate element is at least more flexible than the rigid contact element. The flexible intermediate element can have a lighter weight and a smaller cross section than the rigid contact element. The flexible intermediate element can preferably be a wire. The wire can be chosen to be longer than the spacing between the contact element and the transducer element and can thus not be stretched tightly.

[0024] In this way, the rigid contact element can advantageously be acoustically decoupled from the vibrating ultrasonic membrane.

[0025] According to one embodiment, the at least one heat-staked plastic element comprises a protrusion protruding inwardly from the plastic housing, the protrusion extending through a through opening in the contact element, and a free head end of the protrusion being heat-staked such that it engages form-fittingly behind the contact element.

[0026] The "free head end" of the protrusion is understood to mean in particular the end of the protrusion that is remote from the plastic housing.

[0027] The present embodiment advantageously allows the contact element to be precisely positioned during production of the proposed ultrasonic transceiver. The protrusion can be introduced into the through opening, and the free head end can then be widened by heat-staking, into a mushroom head shape. A stable form-fitting between the contact element and the heat-staked free head end of the protrusion and the plastic housing can thus be obtained.

[0028] According to another embodiment, the at least one heat-staked plastic element comprises at least two protrusions protruding inwardly from the plastic housing, wherein the contact element is arranged between the at least two protrusions, and wherein the free head ends of the protrusions are heat-staked in such a way that they engage form-fittingly behind the contact element.

[0029] The "free head end" of each protrusion is understood to mean in particular the end of the protrusion that is remote from the plastic housing.

[0030] The present embodiment can allow the contact element to be precisely positioned between the two protrusions during production of the proposed ultrasonic transceiver. The contact element can be placed between the two protrusions, and its free head end can be widened by heat-staking. A stable form-fitting between the contact element and the heat-staked free head ends of the two protrusions and the plastic housing can thus be obtained.

[0031] According to another embodiment, the contact element comprises a rail-shaped section, and a direct form-fitting connection is created between the heat-staked plastic element and the rail-shaped section.

[0032] The rail-shaped section can be supported on the inner surface of the plastic housing and form-fittingly enclosed between the inner surface of the plastic housing and the at least one heat-staked plastic element.

[0033] According to a further embodiment, the contact element comprises a pin-shaped section and has a printed circuit board for activating at least one electronic component of the transducer element plugged on the pin-shaped section.

[0034] Due to the direct form-fit connection between the contact element and the plastic housing produced by the heat staking, the contact element and the plastic housing are acoustically decoupled by the intermediate element, so that a plug-in connection between the printed circuit board and the pin-shaped section of the contact element is advantageously sufficient. The plug-in connection does not need to be encapsulated. Thus, the installation and possible repair or replacement of the printed circuit board can be advantageously simplified.

[0035] According to a further embodiment, the printed circuit board extends parallel to the ultrasonic membrane, a volume inside the plastic housing on a side of the printed circuit board facing the ultrasonic membrane is encapsulated with foam, and a volume inside the plastic housing on a side of the printed circuit board facing away from the ultrasonic membrane is not encapsulated with foam.

[0036] For example, the foam can be a silicone foam. The volume inside the plastic housing on the side facing the ultrasonic membrane can be completely or partially encapsulated with foam. In particular, a volume area of the plastic housing adjoining the ultrasonic membrane can be encapsulated with foam. The ultrasonic membrane can thus be advantageously damped.

[0037] At the same time, at least a volume area of the plastic region on the side of the printed circuit board facing away from the ultrasonic membrane is free of foam. Optionally, also a part of the volume area on the side facing the ultrasonic membrane is free of foam. In particular, according to the proposed solution, the connection between the printed circuit board and the pin-shaped section of the contact element does not need to be encapsulated. Similarly, the connection between the track-shaped section of the contact element and the plastic housing does not necessarily need to be encapsulated.

[0038] Thus, encapsulation compounds can advantageously be saved and the mass of the ultrasonic transceiver can be reduced. This has a positive effect on the structural dynamics, in particular on the decay time of the ultrasonic transceiver.

[0039] According to a second aspect, a method of producing an ultrasonic transceiver for a vehicle is proposed. The method comprises the following steps: forming a plastic housing having at least one plastic element formed integrally with the plastic housing; fastening an ultrasonic membrane with a transducer element in order to excite vibrations of the ultrasonic membrane on the plastic housing and to detect vibrations of the ultrasonic membrane on the plastic housing; arranging an electrically conductive contact element inside the plastic housing; bringing the contact element into contact with the transducer element; and connecting the plastic housing directly and form-fittingly to the contact element by heat staking the at least one plastic element formed integrally with the plastic housing.

[0040] The features, advantages, definitions, and embodiments of the ultrasonic transceiver described above for the first aspect are also applicable to the manufacturing method of the second aspect. The features, advantages, definitions, and embodiments of the manufacturing method of the second aspect described below are also applicable to the ultrasonic transceiver of the first aspect.

[0041] The proposed manufacturing method can advantageously provide improved access and thus simplify installation. Therefore, the injection molding tooling for casting the plastic housing can be designed to be more compact and simpler, and the contact between the contact element and the transducer element can be at least partially achieved with considerable degrees of freedom of movement before the contact element is arranged in the plastic housing and before the plastic housing is connected to the contact element. For example, a wire can be welded to the contact element as an intermediate element before the contact element is arranged in the plastic housing.

[0042] The formation of a plastic housing having plastic elements integrally formed with a plastic housing can include casting, such as injection molding, in a single working step.

[0043] Securing an ultrasonic diaphragm to a transducer element may specifically include the following steps: bonding the transducer element to the ultrasonic diaphragm; and assembling the ultrasonic diaphragm with the transducer element onto a housing.

[0044] The arrangement of contact elements may specifically include placing the contact elements on the inner surface of the plastic housing.

[0045] The contact between the contact element and the transducer element may in particular include welding.

[0046] Thermo-riveting of at least one plastic element may specifically include thermoplastic deformation of at least one plastic element under heat supply, such that after the plastic cools, there is a form-fit connection between the plastic housing, the thermo-riveted plastic element, and the contact element.

[0047] According to one embodiment, a plastic housing is integrally formed with at least one plastic element, the plastic element including at least one protrusion projecting inward from the plastic housing and having a guide ramp at its free end, and the contact element being guided and positioned by the guide ramp during arrangement inside the plastic housing.

[0048] The guide ramp can be formed, for example, by the beveled upper edge of a cuboid protrusion. The guide ramp can also be formed by the conical tip of a cylindrical protrusion.

[0049] In the preferred automated arrangement process within a plastic housing, the introduction of bevels can advantageously aid in the positioning of the plastic components.

[0050] According to one embodiment, at least one plastic element integrally formed with a plastic housing includes a plurality of protrusions that project inwardly from the plastic housing, each having a guide ramp at its free end, and together forming a recess, wherein the arrangement of a conductive contact element inside the plastic housing includes inserting the contact element into the recess, wherein the contact element is guided and positioned by the guide ramp during insertion.

[0051] A “recess” is understood to specifically refer to a volume that is essentially a cuboid, defined by a plastic shell and corresponding protrusions, and formed to precisely mate with a contact element to be inserted into the recess. The volume referred to as a “recess” is not necessarily completely surrounded by the plastic element, but may have gaps on each side.

[0052] In the production process of ultrasonic transceivers, the contact element can be easily inserted in this way, especially automatically by a robotic arm into the recess formed by the protrusion, and thus automatically and preferably precisely positioned in all degrees of freedom except the insertion direction by the guide ramp at the free end of the protrusion.

[0053] According to another embodiment, the contact element is a rigid element, and the electrical contact between the contact element and the transducer element is established via a flexible intermediate element.

[0054] Therefore, the contact element can be advantageously acoustically decoupled from the transducer element, and thus also acoustically decoupled from the ultrasonic diaphragm.

[0055] According to another embodiment, the contact between the contact element and the transducer element includes welding or fusion welding one end of a flexible intermediate element to the contact element before the contact element is arranged in the plastic housing, and welding or fusion welding the other end of the flexible intermediate element to the transducer element after the contact element is arranged in the plastic housing.

[0056] Because the connection between the contact element and the plastic housing is achieved by thermally riveting the plastic element, welding or fusion welding of at least one end of the flexible intermediate element can be performed before the contact element is arranged, which advantageously allows for greater freedom and enables more precise operation.

[0057] According to another embodiment, welding or fusion welding the other end of the flexible intermediate element to the transducer element and thermally riveting at least one plastic element are performed simultaneously in one working step.

[0058] According to another embodiment, the contact between the contact element and the transducer element includes welding or fusion welding one end of a flexible intermediate element to the contact element, and welding or fusion welding the other end of the flexible intermediate element to the transducer element after thermally riveting the plastic element, so as to connect the contact element to the plastic housing.

[0059] The proposed hot-riveting connection between the contact element and the plastic housing eliminates the need for complex injection molding tools or the like, and can be performed in a space-saving manner. This allows welding tools to be introduced into the plastic housing simultaneously with the hot-riveting punch, or a combination tool for welding and hot riveting can be used. Therefore, the energy and time required during the installation of the ultrasonic transceiver can be advantageously reduced.

[0060] Further possible embodiments of the invention include combinations of features or embodiments not explicitly mentioned in the descriptions above or below with reference to exemplary embodiments. In such cases, those skilled in the art will also add individual aspects as improvements or additions to the corresponding basic form of the invention. Attached Figure Description

[0061] Further advantageous configurations and aspects of the invention are the subject of the dependent claims and the exemplary embodiments of the invention described below. The invention will now be explained in more detail based on preferred exemplary embodiments, with reference to the accompanying drawings.

[0062] Figure 1 A cross-sectional schematic diagram of an ultrasonic transceiver according to a first exemplary embodiment is shown;

[0063] Figure 2 A perspective view of the plastic housing is shown before the contact element is inserted and connected according to a second exemplary embodiment;

[0064] Figure 3 It shows Figure 2 The transparent portion of the plastic casing contains the contact element;

[0065] Figure 4 It shows the result after hot riveting. Figure 3 The transparent portion of the plastic casing; and

[0066] Figure 5 The steps of a production method according to an exemplary embodiment are shown.

[0067] Unless otherwise stated, identical or functionally equivalent elements in the figures have the same reference numerals. Detailed Implementation

[0068] Figure 1 A non-scale cross-sectional schematic diagram of an ultrasonic transceiver 1 according to a first exemplary embodiment is shown.

[0069] An ultrasonic transceiver 1 includes a plastic housing 2. An ultrasonic diaphragm 3 for transmitting and receiving ultrasonic signals is assembled on the open lower side of the plastic housing 2. A piezoelectric element 4 (an example of a transducer element) is bonded to the ultrasonic diaphragm 3. The piezoelectric element 4 is configured to excite the ultrasonic diaphragm 3 to vibrate under the control of an electrical signal, and is configured to detect the vibrations of the ultrasonic diaphragm 3 and convert them into electrical signals. A conductive contact element 6 for contacting the piezoelectric element 4 is arranged inside the plastic housing 2. A horizontal section 601 of the contact element 6 rests on the inner surface 7 of the plastic housing 2. The contact element 6 (horizontal section 601) is directly and form-fitted to the plastic housing 2 via the free end of a plastic element 8, which is integrally formed with the plastic housing 2 and is thermally riveted (in... Figure 1 (The example is represented by the shape of a mushroom head).

[0070] It should be noted that the plastic element 8 is also considered a segment of the plastic housing 2, as it is integrally formed with the plastic housing 2. In other words, the plastic housing 2 is thermally riveted in the area of ​​the contact element 6, so that the contact element 6 and segments 7 and 8 of the plastic housing 2 are directly and shape-fittingly connected to each other.

[0071] The ultrasonic transceiver 1 has favorable structural dynamics, reduced structural vibration decay time, increased lifespan, and greater long-term stability of decay time.

[0072] refer to Figure 1 The advantageous configuration and development of the ultrasonic transceiver 1 are further described.

[0073] Specifically, there is a constraint between the plastic housing 2, particularly on the inner surface 7 and the heat-riveted free end of the plastic element 8, and the contact element 6 (segment 601). On the one hand, due to manufacturing tolerances, it may be difficult to achieve static certainty in the connection between the plastic housing 2 and the contact element 6. Static certainty can be ensured by selecting at least slight constraints. On the other hand, the connection between the plastic housing 2 and the contact element 6 can therefore be formed not only form-fittingly but also frictionally.

[0074] Specifically, at least the contact element 6, which is form-fitted to the plastic housing 2, is not directly connected to the piezoelectric element 4. A flexible wire 10 (an example of an intermediate element) is arranged between the rigid contact element 6 and the piezoelectric element 4. The wire 10 is used to acoustically decouple the contact element 6 from the ultrasonic diaphragm 3.

[0075] Specifically, the ultrasonic diaphragm 3 is not directly connected to the plastic housing 2. The ultrasonic diaphragm 3 is attached, for example, to a decoupling ring 19 (also referred to as an "insertion"). The module consisting of the ultrasonic diaphragm 3, the piezoelectric element 4, and the decoupling ring 19 is arranged inside the opening side of the plastic housing 2 and assembled onto the plastic housing 2 via an external annular cover 20. The connection between the cover 20 and the plastic housing 2 can be laser welded. In this way, acoustic decoupling between the plastic housing 2 and the ultrasonic diaphragm 3 with the piezoelectric element 4 can be achieved.

[0076] Specifically, the horizontal portion 601, which is shaped to fit the plastic housing 2, is a conductive track segment (track-shaped segment) that rests flat on the inner surface 7 of the plastic housing 2. Furthermore, the contact element 6 includes another conductive track segment 602, which extends obliquely downwards in the direction of the piezoelectric element 4. Additionally, the contact element 6 includes a contact pin segment 603 (pin-shaped segment) that extends substantially orthogonally upwards relative to the conductive track segment 601. The vertically upward-extending contact pin segment 603 is precisely supported on a protrusion 9, which is not thermally riveted, is integrally formed with the plastic housing 2, and protrudes inwards.

[0077] In the present context, "down" refers to the direction along the main axis of the ultrasonic transceiver 1, the direction in which the ultrasonic signal of the ultrasonic transceiver 1 is transmitted, while "up" correspondingly refers to the opposite direction. It should be understood that the ultrasonic transceiver 1 can be assembled on the vehicle in any desired orientation, and the "down" direction does not necessarily or preferably need to be aligned with the direction of gravity, either during the manufacturing process of the ultrasonic transceiver 1 or during its operation.

[0078] Specifically, the ultrasonic transceiver 2 has another contact pin 11 for external contact, which extends from the main housing section 201 of the plastic housing 2 to the connecting housing section 202 of the plastic housing 2, and is used for external contact. A portion of the other contact pin 11 is in the main housing section 201 of the plastic housing, on the side opposite to the contact pin section 603 of the contact element 6, and protrudes upward parallel to said contact pin section.

[0079] The printed circuit board 12 is inserted from above into the contact pin section 603 of the contact element 6 for contacting the piezoelectric element 4, and is also inserted into the vertical section of another contact pin 11 for external contact. One or more electronic components 13 for activating the piezoelectric element 4 are arranged on the printed circuit board 12.

[0080] Specifically, the volume 501 of the interior 5 of the plastic housing 2 can preferably be at least partially encapsulated with silicone foam on the side of the printed circuit board 12 facing the ultrasonic diaphragm 3. Particularly preferably, the volume 501 can be encapsulated with silicone foam starting from the ultrasonic diaphragm 3 until it reaches a height sufficient to ensure adequate damping of the ultrasonic diaphragm 3 but located below the printed circuit board 12. Advantageously, it is not necessary to encapsulate with silicone foam the connection between the conductive track section 601 of the contact element 6 and the thermally riveted plastic element 8, which is formed by thermal riveting. Similarly, it is not necessary to encapsulate with silicone foam the plug-in connection between the contact pin section 603 of the contact element 6 and the printed circuit board 12. Specifically, the volume 502 on the side of the printed circuit board 12 facing away from the ultrasonic diaphragm 3 is not encapsulated with foam. Thus, compared to complete encapsulation of the plastic housing 2, the amount of silicone foam used can therefore be advantageously reduced to the minimum required for damping the ultrasonic diaphragm 3. As a result, the total mass of the ultrasonic transceiver 1 can be reduced, which can have a favorable effect on structural dynamics and the decay time of structural vibrations.

[0081] The following uses Figures 2 to 5 A method for manufacturing an ultrasonic transceiver 1 and an ultrasonic transceiver 1 according to a second exemplary embodiment are described. The second exemplary embodiment is compatible with the first exemplary embodiment. Identical elements have the same reference numerals and are not described again.

[0082] Figure 2 , 3 Figures 4 and 4 show the steps before inserting and connecting contact elements 61 and 62. Figure 2 After inserting contact elements 61 and 62 ( Figure 3 ) and after hot riveting ( Figure 4 The plastic shell 2 has a perspective view and is in basically the same proportions. Figure 5 The steps of the production method are shown.

[0083] In step S1, the plastic housing 2 is formed as a single piece during injection molding. The plastic housing 2 has an inner surface 7, from which protrusions 8 and 9, integrally formed with the plastic housing 2, protrude vertically inward. Protrusions 801, 802, 803, and 804 are examples of at least one plastic element 8 to be heat-riveted. Protrusion 9 is a protrusion not to be heat-riveted.

[0084] Each protrusion 8, 9 has its own guide ramp 14-17 at its free end (the end furthest from the inner surface 7 of the plastic housing). Specifically, the cylindrical protrusion 801 has a tapered tip serving as the guide ramp 14. At their free ends, the wall-shaped (cubic-piezo) protrusions 802 and 803 have beveled edges 15, 16 serving as their respective guide ramps. At their free ends, the wall-shaped protrusion 9, which is not thermally riveted, has a beveled edge 17 serving as the guide ramp.

[0085] The cylindrical protrusion 801, the wall-shaped protrusions 802 and 803, and the protrusion 9 that is not thermally riveted together form the recess 18. The recess 18 represents a contact element ( Figure 3 The volume region 61 can be inserted therein, and the volume region is surrounded by different plastic elements 7, 9, 14, 15, 18, which are thermally riveted as described below to establish a direct and form-fitting connection with the contact element 61.

[0086] Reference Figure 5 and Figure 1 Step S2 is described. In step S2, the ultrasonic diaphragm 3, having the piezoelectric element 4, is fastened to the plastic housing 2. Specifically, the piezoelectric element 4 is bonded to the ultrasonic diaphragm 3. The ultrasonic diaphragm 3 is attached to the decoupling ring 19. The module consisting of the ultrasonic diaphragm 3, the piezoelectric element 4, and the decoupling ring 19 is arranged inside the opening side of the plastic housing 2 and assembled onto the plastic housing 2 from the outside via the outer cover 20. The connection between the outer cover 20 and the plastic housing 2 is laser welded.

[0087] Now for reference Figure 3 and Figure 5 In step S3, contact elements 61 and 62 are inserted into the recess 18 and thus arranged inside the interior 5 of the plastic housing 2. During insertion, contact element 61 is guided by guide ramps 14-17 and precisely positioned in all degrees of freedom except the insertion direction.

[0088] Contact element 61 is described by way of example. It should be understood that contact element 62 is constructed in the same manner. Contact element 61 has a vertically upward extending contact pin section 603, a conductive track section 601 resting on the inner surface 7 of the plastic housing 2, and a conductive track section 602 extending obliquely downward in the direction of the ultrasonic diaphragm 3. Figure 1 The conductive track section 601 has a through opening 21 through which the cylindrical protrusion 801 extends with a precise fit after the contact element 61 is inserted. During insertion, the conductive track section 601 is precisely positioned between two wall-shaped protrusions 802 and 803. Furthermore, the rear side of the vertically upward-extending contact pin section 603 of the contact element 61 is precisely supported on a protrusion 9 that is not thermally riveted.

[0089] Reference Figure 5 and Figure 1Step S4 is described. In step S4, the contact element 6 contacts the piezoelectric element 4. Step S4 does not necessarily need to occur after step S3 and / or before step S5, but can occur wholly or partially at one or more other points in time. For example, before insertion in step S3, one end of the wire 10 may advantageously have been welded to one end of the downwardly extending segment 602 of the corresponding contact element 6. After insertion in step S3, the other end of the wire 10 may be welded to the piezoelectric element 4, and the contact between the corresponding contact element 6 and the piezoelectric element 4 is thus completed. Particularly preferably, the following thermal riveting of the protrusions 801-804 and the welding of the wire 10 to the piezoelectric element 4 in step S5 can occur simultaneously in one working step by introducing a punch for thermal riveting and a welding tool, or a combination tool for thermal riveting and welding, into the plastic housing 2.

[0090] Now for reference Figures 3 to 5 In step S5, protrusions 801, 802, 803, and 804 ( Figure 3 The free ends of the plastic housing 2 are thermally riveted, resulting in a direct, form-fitting, and advantageously frictional connection between the plastic housing 2 and the contact elements 61 and 62. This leads to Figure 4 The configuration shown. In Figure 4 As can be seen, in the case of the second contact element 62, the cylindrical protrusion 804 protrudes through the through opening 22 of the contact element 22, and the free end of the protrusion 804 is thermally riveted in such a way that it is form-fitted into the rear of the contact element 62. The same applies to the cylindrical protrusion 801 and the contact element 61. Furthermore, the free ends of the protrusions 802 and 803 are arranged on either side of the contact element 61 and melt during the thermal riveting process to form a common thermal riveting joint end of the two protrusions 802 and 803, which form-fitted into the rear of the contact element 61. Moreover, the contact element 61 is precisely positioned in the recess 18 formed by the protrusions 801, 802, and 803 and deforms during the thermal riveting process, thus directly and form-fittingly connected to the plastic housing 2.

[0091] The production method may include Figure 5 Other steps not shown. See reference. Figure 1Specifically, a pull-out test can be performed in another step to determine whether the connection between contact element 6 and plastic housing 2 is sufficiently statically overstressed and friction-resistant. Specifically, the volume 501 of plastic housing 2 can then be partially encapsulated with silicone foam on one side of the ultrasonic diaphragm 3 to dampen the ultrasonic diaphragm. However, according to the proposed scheme, it is not necessary to completely encapsulate contact elements 6, 61, and 62. Thus, printed circuit board 12 can be inserted into the vertical sections of contact pin 603 and contact pin 11 for external contact. Encapsulation is also advantageously unnecessary here. Finally, the upper side of plastic housing 2 can be closed with cover 23. The connection between cover 23 and plastic housing 2 can be, for example, laser welded.

[0092] Although the invention has been described based on exemplary embodiments, it can be modified in various ways. In particular, plastic segments of the plastic housing 2, shaped and arranged in any desired manner, can be thermally riveted as long as a direct form-fit connection is established between the plastic housing 2 and the contact element 6.

[0093] List of reference numerals

[0094] 1. Ultrasonic transceiver

[0095] 2. Plastic casing

[0096] 3. Ultrasonic membrane

[0097] 4. Transducer elements and piezoelectric elements

[0098] 5. The interior of the plastic casing

[0099] 6 Contact elements

[0100] 7. Inner surface of the plastic casing

[0101] 8 Plastic components

[0102] 9. Non-thermal riveting protrusions

[0103] 10 Intermediate components, wires

[0104] 11 Contact pins for external contact

[0105] 12 Printed Circuit Boards

[0106] 13 Electronic components

[0107] 14-17 Importing Inclined Surfaces

[0108] 18 concavity

[0109] 19 Decoupling Ring

[0110] 20 lids

[0111] 21, 22 Through openings

[0112] 23 Cover

[0113] Contact elements 61 and 62

[0114] 201 Main Casing Section

[0115] 202 Connecting housing section

[0116] The internal volume of the 501 and 502 plastic outer shells

[0117] 601 Horizontal section and conductive track section of contact element

[0118] 602 The downwardly extending conductive track section of the contact element

[0119] 603 Contact pin section of contact element

[0120] 801, 804 columnar protrusions

[0121] 802 and 803 are cuboid protrusions with wall-like shapes.

Claims

1. An ultrasonic transceiver (1) for a vehicle, wherein The ultrasonic transducer (1) has a plastic housing (2), an ultrasonic membrane (3), a transducer element (4) for exciting vibrations of the ultrasonic membrane (3) and for detecting vibrations of the ultrasonic membrane (3), and an electrically conductive contact element arranged in an interior (5) of the plastic housing for electrically contacting the transducer element (4), wherein the plastic housing (2) and the contact element are directly and form-fittingly connected to each other by at least one plastic element (8) which is integrally formed with the plastic housing (2) by heat staking, wherein the contact element comprises a track-shaped section (601), wherein the at least one heat-staked plastic element (8) comprises at least two protrusions (802, 803) which protrude inwardly from the plastic housing (2), wherein the contact element comprises a first contact element (61) and a second contact element (62), wherein the track-shaped section of the first contact element (61) is arranged between the at least two protrusions (802, 803), and wherein the free head ends of the protrusions (802, 803) are heat-staked such that they directly and form-fittingly engage behind the track-shaped section of the first contact element (61).

2. The ultrasonic transceiver of claim 1, wherein, A constraint exists between the plastic housing (2) and the contact element.

3. The ultrasonic transceiver according to claim 1 or 2, characterized in that, The contact element is a rigid element, and the electrical contact between the contact element and the transducer element (4) is established via a flexible intermediate element (10).

4. The ultrasonic transceiver of claim 1 or 2, wherein, The at least one heat-staked plastic element (8) comprises a protrusion (804) which protrudes inwardly from the plastic housing (2), extends through a through-opening (22) in the second contact element (62), and whose free head end is heat-staked such that it form-fittingly engages behind the second contact element (62).

5. The ultrasonic transceiver of claim 1 or 2, wherein, The contact element comprises a pin-shaped section (603), and a printed circuit board (12) for activating at least one electronic component (13) of the transducer element (4) is plugged onto the pin-shaped section (603).

6. The ultrasonic transceiver of claim 5, wherein, The printed circuit board (12) extends parallel to the ultrasonic membrane (3), a volume (501) of the interior (5) of the plastic housing (2) on a side of the printed circuit board (12) facing the ultrasonic membrane (3) is at least partially encapsulated with foam, and a volume (502) of the interior (5) on a side of the printed circuit board (12) facing away from the ultrasonic membrane (3) is not encapsulated with foam.

7. A method for producing an ultrasonic transducer (1) for a vehicle, having the following steps: forming (S1) a plastic housing (2) having at least one plastic element (8) integrally formed with the plastic housing (2); fastening (S2) an ultrasonic membrane (3) with a transducer element (4) so as to excite vibrations of the ultrasonic membrane on the plastic housing (2) and to detect vibrations of the ultrasonic membrane on the plastic housing; arranging (S3) an electrically conductive contact element in an interior (5) of the plastic housing (2); contacting (S4) the contact element with the transducer element (4); and directly and form-fittingly connecting the plastic housing (2) to the contact element by heat staking (S5) the at least one plastic element (8) which is integrally formed with the plastic housing (2), wherein, in the arranging (S3) step, the contact element comprises a first contact element (61) and a second contact element (62), a track-shaped section of the first contact element (61) is arranged between the at least two protrusions (802, 803), and, in the heat staking (S5) step, the free head ends of the protrusions (802, 803) are heat staked so that they directly and form-fittingly engage behind the track-shaped section (601) of the first contact element (61).

8. The method of claim 7, wherein, The plastic housing (2) is integrally formed with the at least one plastic element (8) which comprises at least one protrusion (801, 802, 803, 804) protruding inwardly from the plastic housing (2) and has a lead-in chamfer (14-16) at its free head end, wherein the contact element (61, 62) is guided and positioned by the lead-in chamfer (14-16) during the arranging (S3) inside the plastic housing (2).

9. The method of claim 8, wherein, The at least one plastic element (8) which is integrally formed with the plastic housing (2) comprises a plurality of protrusions (801, 802, 803) protruding inwardly from the plastic housing, the plurality of protrusions having respective lead-in chamfers (14-16) at their free head ends and together forming a recess (18), wherein the arranging (S3) of the electrically conductive contact element (61, 62) inside the plastic housing (2) comprises inserting the contact element (61, 62) into the recess (18), wherein the contact element (61, 62) is guided and positioned by the lead-in chamfers (14-16) during the insertion.

10. The method according to any one of claims 7 to 9, characterized in that, The contact element is a rigid element, and the electrical contact between the contact element and the transducer element (4) is established via a flexible intermediate element (10).

11. The method of claim 10, wherein, The contacting (S4) of the contact element with the transducer element (4) comprises: welding one end of the flexible intermediate element (10) to the contact element before arranging (S3) the contact element in the plastic housing (2); welding the other end of the flexible intermediate element (10) to the transducer element (4) after arranging the contact element in the plastic housing (2).

12. The method of claim 11, wherein, Welding the other end of the flexible intermediate element (10) to the transducer element (4) and heat staking (S5) the at least one plastic element (8) are carried out simultaneously in one work step.

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