Coil arrangement and sensor having such a coil arrangement

Abstract

With regard to a particularly secure positioning of a coil arrangement in a receiving device or in a housing for the coil arrangement using structurally simple means, a coil arrangement having a coil body (1) and at least one coil (2) arranged on the coil body (1), the coil body (1) being assigned at least one spring element (4) for positioning the coil body (1) during the installation of the coil body (1) in a receiving device or in a housing, is designed and developed in such a way that the at least one spring element (4) is formed integrally with the coil body (1). The invention also discloses a sensor having such a coil arrangement.

Description

[0001] COIL ARRANGEMENT AND SENSOR WITH SUCH A COIL ARRANGEMENT

[0002] The invention relates to a coil arrangement with a coil body and at least one coil arranged on the coil body, wherein the coil body is assigned at least one spring element for positioning the coil body during the assembly of the coil body in a receiving device or in a housing.

[0003] Furthermore, the present invention relates to a sensor with such a coil arrangement.

[0004] Coil arrangements and sensors with such a coil arrangement are known from practical applications and exist in various embodiments. For example, in eddy current sensors, it is necessary that a coil arrangement within a housing, comprising a coil mounted on or wound onto a coil former, maintains a defined distance from an end face of the housing, typically a cover plate. The available measuring range of the eddy current sensor begins with the design and arrangement of the coil. This means that the coil must be positioned as close as possible, i.e., without any loss of space, to the inner end face of the housing, i.e., the cover plate. To obtain correct, reproducible measurement results, it is essential that the position of the coil arrangement within the housing or sensor housing remains unchanged after sensor manufacturing. This must be guaranteed throughout the sensor's service life.

[0005] The current assembly method for the coil assembly requires many separate parts to press the assembly against the end face of the housing (cover plate) using pre-assembled spring elements and their deformation force. The spring elements currently used are made of foam (plastic). In the simplest case, these are defined sections of a round cord, also known as a round profile. This can be made of various plastics, preferably silicone foam. These round cord sections are positioned between a stop surface in the housing opposite the end face and the coil during assembly.

[0006] Applying adhesive to the round cord segments is very time-consuming, and their subsequent positioning on the spool cannot currently be guaranteed with absolute reproducibility. Uneven positioning of the round cord segments on the spool may lead to inhomogeneous force application, and consequently, there is a risk of the spool assembly tilting within the sensor housing. This can negatively affect the measurement.

[0007] Furthermore, consistent spring forces (resilience of the foam) cannot be guaranteed for the individual round cord sections. Different spring forces can occur due to varying thicknesses of the round cord sections. Additionally, foams of varying ages can lead to different spring forces. This can also result in an undefined position of the coil assembly and negatively affect the measurement.

[0008] When metallic spring elements are used in the immediate vicinity of the coil winding area, the material of the spring elements has an undefined adverse effect on the acting magnetic field and thus negatively influences the measurement results. For example, sensors are known from US 7,170,385 B2 in which a spring element in the form of a leaf spring 50 presses a coil assembly 34 against the inner end face 62 of a housing 20 and thus against a cover plate.

[0009] The present invention is based on the objective of providing a coil arrangement and a sensor with such a coil arrangement, whereby a particularly secure positioning of a coil arrangement in a receiving device or in a housing for the coil arrangement is ensured by structurally simple means. According to the invention, the aforementioned objective is achieved by a coil arrangement with the features of claim 1 and by a sensor with the features of claim 9. Accordingly, the coil arrangement according to the invention is designed and further developed such that the at least one spring element is formed integrally with the coil body.

[0010] In accordance with the invention, it has first been recognized that the aforementioned problem can be solved in a surprisingly simple manner by cleverly implementing the spring element. In a further aspect of the invention, the at least one spring element is formed integrally with the coil former. This integral formation of the at least one spring element with the coil former allows for particularly simple assembly of the coil former in a receiving device or in a housing for the coil former. It is no longer necessary to connect one or more spring elements to the coil former, possibly by hand, or to position them at suitable locations on the coil former. The use of an additional adhesive is also no longer required.Rather, the at least one elastic spring element can be implemented at a suitable position on the coil former during its manufacture and then easily arranged in the receiving device or housing, whereby the at least one spring element is thereby virtually automatically positioned at a desired position relative to the receiving device or housing. In this case, the coil former and the at least one spring element form a single unit.

[0011] Consequently, the coil arrangement and the sensor according to the invention with such a coil arrangement provide a coil arrangement and a sensor whereby a particularly secure positioning of a coil arrangement in a receiving device or in a housing for the coil arrangement is ensured by structurally simple means.

[0012] In one specific embodiment, the at least one spring element can be designed as a spring tongue. This results in a structurally particularly simple and effective, and therefore safe, design of a spring element.

[0013] Furthermore, with a view to a particularly simple design, the at least one spring element can be single-legged, arcuate, or ring-shaped. The spring element, or each spring element, can have a leg that can sensing from a flat area of ​​the coil former. Depending on the application and requirements, the at least one spring element can be arcuate or arcuate, similar to a leaf spring. In another alternative and structurally simple embodiment, the spring element can be essentially ring-shaped, in which case it can be arranged around a central axis of the coil former.

[0014] With a view to a particularly simple design, at least one spring element and / or the coil former can be made of plastic. Especially when the coil former is used with a sensor, this largely avoids negative influences on the generated magnetic field and thus on the measurement result, such as can occur with a metal spring element and / or coil former.

[0015] In a further simple and reliable manner, the at least one spring element, together with the coil body, can be manufactured by a casting or injection molding process. This allows the shape and design of the at least one spring element to be easily and reliably defined in order to meet the requirements of the respective application.

[0016] For particularly secure positioning, multiple spring elements can be implemented, whereby the multiple spring elements can be arranged equidistant from each other and / or around a central axis of the coil former at equal angular intervals from each other. This allows for a particularly uniform spring force distributed across the coil former, resulting in particularly secure positioning of the coil former in a holding device or housing.

[0017] Depending on the application, the spring force of the at least one spring element can be implemented such that the coil former is preferably pressed and / or held uniformly against the inside or end face of the housing in an axial direction. This allows for particularly secure positioning of the coil former within the housing.

[0018] Furthermore, depending on the application, the spring force of the at least one spring element can be implemented in such a way that the coil former is held in a defined position relative to the receiving device or housing during external influences – for example, shock and / or vibration. This design is particularly suitable in cases where the receiving device or housing remains unfilled with potting compound and the at least one spring element must ensure the positioning of the coil former, for example, throughout the entire service life or operating period of a sensor.

[0019] Depending on the application, the sensor according to the invention can, for example, be an inductively operating sensor or an eddy current sensor.

[0020] In exemplary embodiments of the coil body, the previously required step of arranging or gluing the at least one spring element onto the coil body, for example three round cord pieces, is advantageously and time-savingly eliminated.

[0021] In further embodiments of the coil former, the force required for positioning the coil former can be achieved by directly integrating or integrally incorporating several single-legged spring elements within or on the coil former and by designing the geometry of these spring elements according to the intended application. This allows the coil to be held axially aligned and positioned against an inner housing end face of an eddy current sensor. The geometry of the spring elements is designed to withstand shock and vibration permanently and elastically, even without subsequent potting of the housing interior.

[0022] The spring tongues can be evenly distributed radially on an inner cover plate of the coil former to distribute the contact force evenly. For example, in one application, the calculated spring force of three spring tongues might be approximately 7 N.

[0023] There are now various ways to advantageously develop and further refine the teaching of the present invention. For this purpose, reference is made, on the one hand, to the dependent claims and, on the other hand, to the following explanation of preferred embodiments of the coil arrangement and the sensor according to the invention with reference to the drawing. In conjunction with the explanation of the preferred embodiments with reference to the drawing, generally preferred embodiments and further developments of the teaching are also explained. The drawing shows

[0024] Fig. 1 shows a perspective view of an embodiment of the coil arrangement according to the invention.

[0025] Fig. 2 shows a side view of the embodiment of the coil arrangement according to the invention from Fig. 1 ,

[0026] Fig. 3 shows a side view and a top view of the embodiment of the coil arrangement according to the invention from Fig. 1 ,

[0027] Fig. 4 in a cutaway view, installed in a housing, the embodiment of the coil arrangement according to the invention from Fig. 1 ,

[0028] Fig. 5 shows a perspective view of a coil arrangement known from practice, and Fig. 6 shows a cutaway view of the known coil arrangement from Fig. 5, installed in a housing.

[0029] Figure 5 shows a perspective view of a coil arrangement known from practical applications, in its unconfigured and undeformed state. The coil arrangement comprises a coil former 1 and a coil 2 wound onto the coil former 1. The coil 2 has individual turns, which are not shown here for simplicity. In addition to the contact point 3 for the coil 2 – a contact for data processing – the coil former 1 shown in Figure 5 has three spring elements 4 in the form of round cord segments 5. These round cord segments 5 have a predetermined degree of elastic deformability and possess a restoring capacity. This means that when the round cord segments 5 are deformed, for example by compression, they tend to return to their original state. This tendency occurs with a defined force. This is also referred to as spring force, which is material-dependent.The function of the round cord segments 5 is to press or hold the coil assembly or an underside 6 of the coil body 1 against an inner end face of a housing (not shown) or its cover plate, at least until a potting compound, which is used for the final fixing of the coil assembly in a sensor housing, has hardened. A fixed position of the coil assembly within the sensor housing is crucial for correct and reproducible measurement results from the eddy current sensor. The coil body 1 is essentially cylindrical with a circumferential recess 7 for the coil 2 arranged therein.

[0030] Figure 6 shows a cutaway view of the known coil arrangement in an installation position within a housing 8. It can be seen that the round cord sections 5 are deformed and compressed. The spring force exerted by the elastic recovery of the round cord sections 5 presses the coil arrangement against the inner face of the housing 8, and more precisely against its cover plate 9. The contact surface 10 of the sensor housing 8, which is formed inside the sensor housing 8, serves as the contact surface for the round cord sections 5.

[0031] Fig. 1 shows a perspective view of an embodiment of the coil arrangement according to the invention, comprising a coil former 1, a coil 2 wound on the coil former 1 and arranged in a recess 7 of the coil former, and a contact 3. For the sake of simplicity, the windings of the coil 2 are not shown. The coil former 1 according to Fig. 1 has three single-legged spring elements 4 in the form of spring tongues. The spring elements 4 and the coil former 1 are formed in one piece and therefore constitute a single unit. The spring tongues are not subsequently attached, molded, or added to the coil former 1 by any other joining techniques, but are created in the same process step during the manufacture of the coil former 1. The manufacturing process for the coil former 1 with the integrated spring elements 4 is an injection molding process in the embodiment shown here.For the material selection of the coil former 1 with integrated spring elements 4, various plastics – for example, thermoplastics, thermosets, elastomers, etc. – can be used, either filled or unfilled. It is also possible to add various additives and / or other substances to the respective plastic matrix, such as flow improvers.

[0032] The spring tongues replace the function of the round cord sections 5. Consequently, the spring tongues must also exhibit a restoring capacity after deformation. Depending on the design of the spring tongues – angle, geometry, wall thickness, spring width, material selection – different spring forces can be achieved. In the application described here as an example, the total spring force of the three spring tongues is approximately 7 N.

[0033] The number of spring elements 4 or spring tongues is not fixed. Thus, coil bodies 1 with only one spring element 4 or spring tongue, or with several spring elements 4 or spring tongues, are possible. If necessary, a structural adjustment of the sensor design and / or the design of the coil body 1 is required to prevent tilting within the sensor housing 8. The embodiment shown in Fig. 1 illustrates an exemplary coil arrangement with a coil body 1 with three spring elements 4, each designed as a single-legged spring tongue. However, differently shaped spring elements 4 are also possible. For example, an arc-shaped protrusion would be feasible. The operating principle would then be similar to that of a leaf spring.

[0034] Fig. 2 shows the coil arrangement from Fig. 1 in a side view. F1 / 3 denotes the spring force of the individual spring element 4. The total acting spring force is to be divided by the number of spring elements 4, where in the illustrated embodiment the number of spring elements 4 or spring tongues is three.

[0035] Fig. 3 shows a side view and a top view of the embodiment of the coil arrangement according to the invention from Fig. 1. Visible are the coil former 1, the contacts 3 formed with contact pins, and the single-legged spring elements 4 in the form of spring tongues belonging to the coil former 1. The arrangement of the spring tongues is preferably uniformly distributed, but this is not mandatory. Ideally, for three spring elements 4 or spring tongues, a uniform distribution would correspond to an arrangement in which the spring elements 4 or spring tongues are each offset from one another by 120° relative to a central axis 11. Due to other design requirements, other arrangements may need to be selected. In the embodiment according to Fig. 3, an arrangement of 135° to 90° to 135° is implemented. With a different number of spring elements 4, the angular dimension or the angular spacing changes again.

[0036] Fig. 4 shows a cutaway view of the exemplary embodiment of the coil arrangement according to the invention from Fig. 1, wherein the coil arrangement is installed in a housing 8. The spring elements 4 or spring tongues belonging to the coil body 1 and arranged around a central axis 11 press the coil body 1 against an inner end face of a housing 8, and more precisely against a cover plate 9 of the housing 8. A contact surface 10 of the sensor housing 8, formed inside the sensor housing 8, serves as the contact surface for the spring elements 4 or spring tongues. The spring force of the spring elements 4 or spring tongues is not fixed. Sensor variants with or without subsequent potting are possible. Variants with potting only need to hold the coil arrangement correctly in position until the potting compound has hardened. After hardening, the potting compound compensates for shock or vibration.In variants without potting, the spring elements 4 of the coil body 1 must keep the coil assembly in a defined position within the housing 8 throughout the sensor's lifetime. External influences such as shock and vibration must also be compensated for by the spring elements 4. Depending on the variant, a design adjustment of the spring force is necessary. This can be achieved through the number of spring elements 4, the geometry, the choice of material, etc.

[0037] One embodiment of the coil arrangement can be used as an inductor, preferably for inductive sensors or eddy current sensors. In this embodiment, a coil former 1 has at least one coil 2 wound or wound onto the coil former 1. The coil former 1 has at least one resilient or elastic element in the form of a spring element 4, preferably three resilient or elastic elements 4, which can serve for the defined and permanent positioning of the coil former 1 within a sensor housing 8, wherein the coil former 1 and the at least one resilient or elastic element 4 are formed as a single unit or in one piece.

[0038] The at least one spring element 4 of the coil former 1 can be designed such that its spring force is sufficient to press and / or hold the coil former 1 uniformly against a housing end face or cover plate 9 of a housing 8 in the axial direction. Alternatively, the spring force of this resilient or elastic element 4 can be realized by appropriate design of the resilient or elastic element 4 such that the coil former 1 is held in a defined position relative to the housing 8 even during external influences such as shock and vibration. For further advantageous embodiments of the coil arrangement and the sensor according to the invention, reference is made to the general part of the description and to the appended claims to avoid repetition.

[0039] Finally, it should be expressly pointed out that the exemplary embodiments described above serve only to illustrate the claimed teaching, but do not limit it to these exemplary embodiments.

[0040] Reference symbol list

[0041] 1 coil former

[0042] 2 coils

[0043] 3 Contacting

[0044] 4 spring element

[0045] 5 pieces of round cord

[0046] 6 Underside

[0047] 7 Exclusion

[0048] 8 Housings, sensor housings

[0049] 9 Cover plate

[0050] 10 area

[0051] 11 Central axis

Claims

Claims 1. Coil arrangement with a coil body (1) and at least one coil (2) arranged on the coil body (1), wherein the coil body (1) is associated with at least one spring element (4) for positioning the coil body (1) during the assembly of the coil body (1) in a receiving device or in a housing (8), characterized in that the at least one spring element (4) is formed integrally with the coil body (1).

2. Coil arrangement according to claim 1, characterized in that the at least one spring element (4) is designed as a spring tongue.

3. Coil arrangement according to claim 1 or 2, characterized in that the at least one spring element (4) is single-legged, arcuate or ring-shaped.

4. Coil arrangement according to one of claims 1 to 3, characterized in that the at least one spring element (4) and / or the coil body (1) are made of a plastic.

5. Coil arrangement according to one of claims 1 to 4, characterized in that the at least one spring element (4) together with the coil body (1) is manufactured by a casting process or by injection molding.

6. Coil arrangement according to one of claims 1 to 5, characterized in that several spring elements (4) are realized, wherein the several spring elements (4) are spaced equally apart from each other and / or are arranged around a central axis (11) of the coil body (1) at equal angular distances to each other.

7. Coil arrangement according to one of claims 1 to 6, characterized in that a spring force of the at least one spring element (4) is realized such that the coil body (1 ) is preferably pressed and / or held in an axial direction uniformly against an inner housing or housing end face.

8. Coil arrangement according to one of claims 1 to 7, characterized in that a spring force of the at least one spring element (4) is realized in such a way that the coil body (1 ) is held in a defined position relative to the receiving device or the housing (8) during external influences - for example shock and / or vibration.

9. Sensor with a coil arrangement according to one of claims 1 to 8.

10. Sensor according to claim 9, characterized in that the sensor is an inductively operating sensor or an eddy current sensor.

Images