Ultrasonic sensor for a motor vehicle
Patent Information
- Application Number
- EP2023712801
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-04-05
- Filing Date
- 2023-03-15
- Publication Date
- 2025-02-12
AI Technical Summary
Current ultrasonic sensors for motor vehicles have complex designs with a high number of individual parts and joining steps, leading to increased manufacturing costs and complexity.
The ultrasonic sensor design features a cup-shaped membrane with a protruding membrane wall positively connected to the sensor housing using a first potting compound that extends into the membrane interior, providing a sealing and mechanical decoupling function while simplifying the construction and assembly process.
This design results in a simplified assembly process with reduced manufacturing costs and a reliable positive connection between the membrane and sensor housing, enhancing the ultrasonic sensor's performance and durability.
Smart Images
Figure 1.1
Abstract
Description
[0001] Description
[0002] Ultrasonic sensor for a motor vehicle
[0003] The invention relates to an ultrasonic sensor for a motor vehicle, comprising a sensor housing and a pot-shaped membrane connected to the sensor housing. The membrane has a membrane base for transmitting and / or receiving ultrasonic signals and a membrane wall adjoining the membrane base, and a portion of the membrane wall protrudes into the sensor housing. A first potting compound is arranged in the interior of a housing portion of the sensor housing facing the membrane base, filling this interior.
[0004] Today's motor vehicles usually have a number of ultrasonic sensors that control driver assistance systems such as parking and / or.
[0005] Brake assistance systems, and provide information about the surroundings of the motor vehicle, in particular about obstacles or objects in the surroundings and their distances from the vehicle. The ultrasonic sensors are distributed throughout the motor vehicle, at least in the front and rear areas of the vehicle, and are usually installed on trim parts, particularly on bumpers.
[0006] Such an ultrasonic sensor is generally arranged in a corresponding opening or recess in the trim part of the motor vehicle in such a way that a front-side or front-side membrane base of a cup-shaped membrane of the ultrasonic sensor is substantially flush with the outer surface of the trim part, whereby ultrasonic waves can be emitted and received via the membrane base during operation.
[0007] An ultrasonic sensor of the type mentioned above is known, for example, from DE 10 2006 028 214 A1. The ultrasonic sensor comprises a substantially cylindrical sensor housing and a pot-shaped diaphragm mounted on the sensor housing, which diaphragm has a disc-shaped diaphragm base. A piezo element is arranged on the inside of the diaphragm base, which can cause the diaphragm base to vibrate, so that it can generate ultrasonic signals. The diaphragm is surrounded radially on the outside by an annular decoupling element, which decouples the diaphragm from the sensor housing in terms of vibration, and which is mounted on the housing side on an annular housing section of the sensor housing, which radially surrounds a part of the decoupling element facing the sensor housing. The decoupling element and the housing section are connected to one another via locking means.A potting compound is also arranged in the interior of the sensor housing to protect the ultrasonic sensor and its electrical components from moisture and dirt.
[0008] The disadvantage of such a design is the associated high number of individual parts and joining steps, which leads to complex production and overall high manufacturing costs.
[0009] The present invention is based on the object of providing an improved design for an ultrasonic sensor whose structure is simplified and which comprises the smallest possible number of individual parts and joining steps in the manufacturing process.
[0010] The above object is achieved by the teaching of claim 1. Expedient embodiments and further developments of the invention are set out in the subclaims and the following description.
[0011] Accordingly, an ultrasonic sensor for a motor vehicle comprises a sensor housing and a pot-shaped membrane connected to the sensor housing, wherein the membrane has a membrane base for emitting and / or receiving ultrasonic signals and a membrane wall adjoining the membrane base, wherein a section of the membrane wall projects into the sensor housing, and wherein a first potting compound filling this housing interior is arranged in a housing interior of a housing section of the sensor housing facing the membrane base.
[0012] According to the invention, the first potting compound extends at least partially into the membrane interior of the membrane surrounded by the membrane wall, wherein the membrane is positively connected to the sensor housing by the first potting compound.
[0013] As a result, the membrane is already attached to the sensor housing by the first potting compound and fixed relative to it. In addition to providing a sealing function and mechanical decoupling between the membrane and the sensor housing, the first potting compound also creates a corresponding positive fit.
[0014] The embodiment according to the invention therefore has the overall advantage that it provides an improved design for an ultrasonic sensor whose construction and assembly are simplified.
[0015] In order to allow the membrane wall to protrude into the sensor housing, an outer diameter of the membrane wall is smaller than an inner diameter of the sensor housing.
[0016] The membrane is advantageously formed in one piece with its membrane base and its membrane wall and is preferably made of aluminum.
[0017] In an advantageous embodiment, a positive connection is achieved at least in one axial direction and in one radial direction. The positive connection thus occurs at least in the axial and radial directions.
[0018] In a further advantageous embodiment, a gap is formed in the housing interior between the outer side of the membrane wall projecting into the sensor housing and the inner side of the housing wall of the housing section, wherein the first potting compound extends at least partially into the gap. The first potting compound is thus supported on the outer side of the membrane wall and the inner side of the housing wall. Advantageously, the first potting compound extends completely into the gap, so that the first potting compound completely fills the gap. This ensures a reliable form fit in this area, at least in the radial direction.
[0019] In a further advantageous embodiment, a radially outwardly extending shoulder is provided on the axial end of the diaphragm wall facing away from the diaphragm base, extending in a collar-like manner around the axial end of the diaphragm wall, in particular completely. This enables a particularly suitable form-fitting connection. The shoulder preferably extends radially outward perpendicular to the diaphragm wall.
[0020] In a further advantageous embodiment, a groove corresponding to the projection of the membrane wall is provided in the first potting compound, wherein the projection is arranged in the groove, thereby creating a positive connection at least in the axial and radial directions. The first potting compound thus has a groove corresponding to the circumferential projection and for receiving the projection, wherein, in the assembled state, the first potting compound completely surrounds the projection.
[0021] In a further advantageous embodiment, an annular, elastic molded part is arranged in an axial section of the intermediate space facing the membrane base, with the projection resting on the molded part and creating a positive connection in the axial direction. In this case, the positive connection is thus created by the first casting compound together with the elastic molded part.
[0022] In a further advantageous embodiment, the first potting compound in the housing interior extends in the radial direction as far as the inside of the housing wall of the housing section, wherein the first potting compound in the diaphragm interior extends in the radial direction as far as the inside of the diaphragm wall. In a further advantageous embodiment, the first potting compound in the diaphragm interior extends in the axial direction as far as the inside of the diaphragm base. Advantageously, the first potting compound completely fills the diaphragm interior. In addition to creating a positive fit, the first potting compound serves in particular to dampen vibrations at the diaphragm base and / or at the diaphragm wall.
[0023] In a further advantageous embodiment, the first potting compound is formed integrally from a first material. Advantageously, the first material is made of an elastomer, thermoplastic, thermoset, or silicone material.
[0024] In a further advantageous embodiment, the first potting compound extends in the diaphragm interior in the axial direction only along a section of the diaphragm wall facing away from the diaphragm base, wherein a second potting compound is arranged immediately adjacent to the first potting compound, which extends in the diaphragm interior in the axial direction from the first potting compound to the inside of the diaphragm base and in the radial direction to the inside of the diaphragm wall. Advantageously, the first potting compound is made of a first material and the second potting compound is made of a second material different from the first material. The second potting compound serves in particular to dampen vibrations at the diaphragm base and / or a section of the diaphragm wall facing the diaphragm base.
[0025] Embodiments of the invention are explained in more detail below with reference to a drawing. In the drawings:
[0026] Fig. 1 a shows an exploded view of an ultrasonic sensor,
[0027] Fig. 1 b shows a cross-section of the ultrasonic sensor according to Fig. 1 a, Fig. 2a shows an exploded view of an ultrasonic sensor in an alternative embodiment,
[0028] Fig. 2b in a cross section the ultrasonic sensor according to Fig. 2a,
[0029] Fig. 3a shows an exploded view of an ultrasonic sensor in a further alternative embodiment,
[0030] Fig. 3b in a cross section the ultrasonic sensor according to Fig. 3a,
[0031] Fig. 4a shows an exploded view of an ultrasonic sensor in a further alternative embodiment,
[0032] Fig. 4b in a cross section the ultrasonic sensor according to Fig. 4a,
[0033] Fig. 5a shows an exploded view of an ultrasonic sensor in a further alternative embodiment, and
[0034] Fig. 5b shows a cross-section of the ultrasonic sensor according to Fig. 5a.
[0035] Corresponding parts are always provided with the same reference symbols in all figures.
[0036] Figs. 1a and 1b show different views of an embodiment of an ultrasonic sensor 1. Fig. 1a shows the ultrasonic sensor 1 in an exploded view, and Fig. 1b shows it in a cross-sectional view.
[0037] The ultrasonic sensor 1 comprises a one-piece sensor housing 2 with a plurality of electrical contact pins 3 and a circuit board 4 arranged within the sensor housing 2 and connected to the contact pins 3. The ultrasonic sensor 1 further comprises a pot-shaped membrane 5 connected to the sensor housing 2, wherein the membrane 5 has a membrane base 6 for emitting and / or receiving ultrasonic signals and a membrane wall 7 adjoining the membrane base 6, and wherein a section of the membrane wall 7 protrudes into the sensor housing 2. Arranged on the inside of the membrane base 6 is a disc-shaped piezoceramic which is electrically connected to the circuit board 4. At the axial end of the sensor housing 4 facing away from the membrane 5, the sensor housing 2 is closed by a cover 8.
[0038] In a housing interior of a housing section 9 of the sensor housing 2 facing the membrane base 6, a first potting compound 10 is arranged which completely fills this housing interior, wherein the first potting compound 10 is formed in one piece from a first material, in particular from an elastomer, thermoplastic, thermoset or silicone material.
[0039] The first potting compound 10 extends in the housing interior of the sensor housing 2 in the radial direction R up to the inside of the housing wall of the housing section 9 of the sensor housing 2. The first potting compound 10 also extends completely into an intermediate space formed between the outside of the membrane wall 7 projecting into the sensor housing 2 and the inside of the housing wall of the housing section 9.
[0040] In addition, the first potting compound 10 extends into the membrane interior of the membrane 5 surrounded by the membrane wall 7, wherein the first potting compound 10 extends in the radial direction R to the inside of the membrane wall 7 and in the axial direction Z to the inside of the membrane base 6. The first potting compound 10 thus completely fills the membrane interior and effects vibration damping at the membrane base 6 and the membrane wall 7.
[0041] Furthermore, at the axial end of the membrane wall 7 facing away from the membrane base 6, there is provided a projection 11 which extends perpendicular to the membrane wall 7 and radially outwards, in the manner of a ring collar, completely around this axial end of the membrane wall 7 and which engages in a groove arranged in the first potting compound 10 and corresponding to the projection 11, so that the first potting compound 10 completely surrounds the projection 11.
[0042] By such a design and arrangement of the first potting compound 10 as a whole in the sensor housing 2 and the membrane interior of the membrane 5 and the membrane 5 in particular with its shoulder 11, a reliable positive connection in the axial direction Z and radial direction R is brought about, wherein the first potting compound 10 thus, in addition to a sealing function, a vibration damping on the membrane base 6 and the membrane wall 7 and a mechanical decoupling between the membrane 5 and the sensor housing 2, also brings about the generation of a corresponding positive connection and thus a reliable fastening of the membrane 5 to the sensor housing 2.
[0043] Figs. 2a and 2b show different views of an alternative embodiment of an ultrasonic sensor 1. Fig. 2a shows the ultrasonic sensor 1 in an exploded view, and Fig. 2b shows it in a cross-sectional view.
[0044] The ultrasonic sensor 1 essentially corresponds to the ultrasonic sensor 1 shown in Figs. 1 a to 1 b, wherein the ultrasonic sensor 1 here has a second potting compound 12 in addition to the first potting compound 10.
[0045] The first potting compound 10 extends in the diaphragm interior in the axial direction Z only along a section of the diaphragm wall 7 facing away from the diaphragm base 6, with the second potting compound 12 being arranged directly adjacent to the first potting compound 10. The second potting compound 12 extends in the diaphragm interior in the axial direction Z from the first potting compound 10 to the inside of the diaphragm base 6 and in the radial direction R to the inside of the diaphragm wall 7. The second potting compound 12 is formed from a second material that is different from the first material of the first potting compound 10. The second potting compound 12 serves in particular to dampen vibrations at the diaphragm base 6 and at the section of the diaphragm wall 7 facing the diaphragm base 6. A material that is particularly suitable for corresponding vibration damping can be used as the second material.
[0046] Figs. 3a and 3b show different views of an ultrasonic sensor 1 in a further alternative embodiment. Fig. 3a shows the ultrasonic sensor 1 in an exploded view, and Fig. 3b shows it in a cross-sectional view.
[0047] The ultrasonic sensor 1 essentially corresponds to the ultrasonic sensor 1 shown in Figs. 1 a to 1 b, wherein the ultrasonic sensor 1 here has, in addition to the first potting compound 10, an annular, elastic molded part 13.
[0048] The elastic molded part 13 is arranged in an axial section of the intermediate space facing the diaphragm base 6 between the outer side of the diaphragm wall 7 projecting into the sensor housing 2 and the inner side of the housing wall of the housing section 9 of the sensor housing 2. The projection 11 formed on the diaphragm wall 7 rests on the molded part 13 and creates a positive connection in the axial direction Z. The positive connection is thus created by the first potting compound 10 together with the elastic molded part 13.
[0049] Figs. 4a and 4b show different views of an ultrasonic sensor 1 in a further alternative embodiment. Fig. 4a shows the ultrasonic sensor 1 in an exploded view, and Fig. 4b shows it in a cross-sectional view.
[0050] The ultrasonic sensor 1 essentially corresponds to the ultrasonic sensor 1 shown in Figs. 2a to 2b, wherein the ultrasonic sensor 1 here has, in addition to the first potting compound 10, an annular, elastic molded part 13.
[0051] The elastic molded part 13 is in turn arranged in an axial section of the intermediate space facing the membrane base 6 between the outer side of the membrane wall 7 projecting into the sensor housing 2 and the inner side of the housing wall of the housing section 9 of the sensor housing 2, wherein the projection 11 formed on the membrane wall 7 rests on the molded part 13, thereby creating a positive connection in the axial direction Z. Thus, in particular, a positive connection is created by the first potting compound 10 together with the elastic molded part 13.
[0052] Figs. 5a and 5b show different views of an ultrasonic sensor 1 in a further alternative embodiment. Fig. 5a shows the ultrasonic sensor 1 in an exploded view, and Fig. 5b shows it in a cross-sectional view.
[0053] The ultrasonic sensor 1 essentially corresponds to the ultrasonic sensor 1 shown in Figs. 1 a to 1 b, wherein here the sensor housing 2 is formed in the shape of a hollow cylinder in the axial end section facing the membrane base 6, and wherein at this axial end section a front cap 14 is connected to the sensor housing 2 via a snap-in connection.
[0054] It is obvious to a person skilled in the art that such a configuration with such a sensor housing 2 and such a front cap 14 is also applicable to the embodiments of Figs. 2a to 4b.
[0055] List of reference symbols
[0056] 1 ultrasonic sensor
[0057] 2 Sensor housing 3 Contact pin
[0058] 4 circuit board
[0059] 5 Membran
[0060] 6 Membrane floor
[0061] 7 Membrane wall 8 Cover
[0062] 9 Housing section of the sensor housing
[0063] 10 first casting compound
[0064] 11 Approach
[0065] 12 second casting compound 13 molded part
[0066] 14 Front cap
[0067] R radial direction
[0068] Z axial direction
Claims
Patent claims 1. Ultrasonic sensor (1) for a motor vehicle comprising a sensor housing (2) and a pot-shaped membrane (5) connected to the sensor housing (2), comprising a membrane base (6) for emitting and / or receiving ultrasonic signals and a membrane wall (7) adjoining the membrane base (6), wherein a section of the membrane wall (7) projects into the sensor housing (2), wherein a first potting compound (10) filling a housing interior of a housing section (9) of the sensor housing (2) facing the membrane base (6) is arranged, thereby indicating that the first potting compound (10) extends at least partially into the membrane interior of the membrane (5) surrounded by the membrane wall (7), and that the membrane (5) is positively connected to the sensor housing (2) by the first potting compound (10).
2. Ultrasonic sensor (1 ) according to claim 1 , characterized in that a positive locking is effected at least in an axial direction (Z) and in a radial direction (R).
3. Ultrasonic sensor (1 ) according to claim 1 or 2, characterized in that an intermediate space is formed in the housing interior between the outside of the membrane wall (7) projecting into the sensor housing (2) and the inside of the housing wall of the housing section (9), and that the first potting compound (10) extends at least partially into the intermediate space.
4. Ultrasonic sensor (1 ) according to one of the preceding claims, characterized in that a radially outward extending, ring-shaped projection (11 ) is provided at the axial end of the membrane wall (7) facing away from the membrane base (6).
5. Ultrasonic sensor (1 ) according to claim 4, characterized in that a groove corresponding to the projection (11 ) of the membrane wall (7) is provided in the first potting compound (10), and that the projection (11 ) is arranged in the groove, thereby effecting a positive locking at least in the axial and radial direction (Z, R).
6. Ultrasonic sensor (1 ) according to one of claims 2 to 4, characterized in that an annular, elastic molded part (13) is arranged in an axial section of the space facing the membrane base (6), and that the projection (11 ) rests on the molded part (13) and causes a positive fit in the axial direction (Z).
7. Ultrasonic sensor (1 ) according to one of the preceding claims, characterized in that the first potting compound (10) in the housing interior extends in a radial direction (R) to the inside of the housing wall of the housing section (9), and that the first potting compound (10) in the membrane interior extends in a radial direction (R) to the inside of the membrane wall (7).
8. Ultrasonic sensor (1 ) according to one of the preceding claims, characterized in that the first potting compound (10) in the membrane interior extends in axial direction (Z) to the inside of the membrane base (6).
9. Ultrasonic sensor (1 ) according to one of the preceding claims, characterized in that the first potting compound (10) is formed in one piece from a first material.
10. Ultrasonic sensor (1) according to one of claims 1 to 8, characterized in that the first potting compound (10) extends in the membrane interior in the axial direction (Z) only along a section of the membrane wall (7) facing away from the membrane base (6), and that a second potting compound (12) is arranged immediately adjacent to the first potting compound (10), which extends in the membrane interior in the axial direction (Z) from the first potting compound (10) extends to the inside of the membrane base (6) and in a radial direction (R) to the inside of the membrane wall (7).