Coil system of an inductive proximity switch mounted in a housing by level or non-level

Abstract

The present disclosure relates to a coil system for an inductive proximity switch mounted flush or non-flush in a housing. The coil system has a coil plate on which the at least one first receiving coil and the transmitting coil are arranged. Here, the transmitting coil comprises a coil designed in a polygonal shape.

Description

Technical Field

[0001] The present disclosure relates to a coil system for an inductive proximity switch which is installed flush or non-flush in a housing. In addition, the present disclosure relates to an inductive proximity switch having a coil system and a method for producing the coil system. Background Art

[0002] Inductive sensors with a winding coil are known in the prior art, which winding coil is inserted into a ferrite core for orienting the electromagnetic field.

[0003] The particular challenge associated with sensor installation is that the sensor should be installed flush in a housing and then be surrounded by the housing in the circumferential direction. Metal housings in particular have a shielding effect, which in particular affects the function of the receiver coil. Therefore, special sensor variants are usually constructed for flush installation, in which the receiver coil has a specific spacing from the surrounding housing. However, this results in the receiver coil having a smaller diameter and poorer detection characteristics in sensors for flush installation compared to variants for non-flush installation.

[0004] The diameter of the ferrite core for flush and non-flush sensors can vary greatly due to the necessary spacing of the coil in the flush installation to achieve internal shielding. This relationship can also be applied to the wound 3-cavity coil (3-Kammer-Spulen) of the Factor 1 sensor.

[0005] In Factor 1 sensors with printed coils, the diameter of the printed coil for the flush sensor variant may also be smaller than the coil diameter for the non-flush sensor variant, or the former may have to be trimmed due to the compensation winding for installation in metal, which may result in the larger switching distances that are common on the market for the non-flush variant not being achieved. Therefore, in these sensors, different coil plates are also available for non-flush and flush sensors.

[0006] In the prior art, various designs of inductive sensors are proposed. An inductive proximity sensor having a transmitting and receiving coil detects the attenuation of a resonant circuit when approaching a metal object (which has a corresponding magnetic property) and switches when a switching distance is reached.

[0007] EP 3 688 871 A1 proposes an inductive proximity switch, which includes a transmitting coil, a receiver coil, an integrated circuit for exciting the transmitting coil and a signal processing unit for processing the signal received by the receiver coil, wherein an oscillator excites a resonant circuit, the resonant circuit includes a transmitting coil and a parallel capacitor for inducing a voltage in the receiver coil, wherein the receiver coil includes two symmetrical segments with opposite orientations and connected in series, wherein the transmitting coil surrounds the above-mentioned segment of the receiver coil, or the transmitting coil is surrounded by the above-mentioned segment of the receiver coil.

[0008] The known solutions have in common that they usually have geometries that cannot be used simultaneously for non-flush sensors and flush sensors with the required standard switching distances. Therefore, different sensor plate variants must always be available for different installation situations. Summary of the invention

[0009] Against the background of this prior art, the object of the present disclosure is to provide a coil system for an inductive proximity switch, an inductive proximity switch and a method for producing a coil system which are respectively suitable for at least partially overcoming the above-mentioned disadvantages of the prior art and for enriching the prior art.

[0010] This object is achieved by the features of the independent patent claims. The content of the dependent claims is correspondingly optional developments of the disclosure.

[0011] The object is thus achieved by a coil system for an inductive proximity switch for flush or non-flush mounting in a housing. The housing can be designed in particular as a metal housing or can at least comprise metal. The coil system has a coil plate, on which at least one first receiving coil and a transmitting coil are arranged. In this case, the first receiving coil comprises a coil designed as a polygon.

[0012] The receiving coil and the transmitting coil can be designed in particular as printed coils. In addition, they can be arranged one above the other in a layered manner.

[0013] In the sense of the present disclosure, a flush or completely flush-mounted sensor may be understood to be a sensor which is completely embedded in the surrounding material of the housing, in particular metal, up to the uppermost sensor surface.

[0014] In the case of non-flush mounted sensors, free space is provided around the sensing surface. It is usually provided that the non-flush mounted sensor protrudes a portion from the housing, in particular so that the coil is not surrounded by metallic material.

[0015] Here, the housing is a component with a surface in which the sensor can be mounted and from which the non-flush sensor protrudes. Therefore, the non-flush sensor is not completely immersed in the metal, so that the metal cannot have a shielding effect.

[0016] The coil system described here for inductive proximity switches offers a number of advantages. The coil system can be formed in particular by a transmitting and receiving coil on a front coil plate (alternatively also by an additional receiving coil), wherein a larger switching distance is obtained in the case of non-flush mounting and a larger switching distance can be achieved even in the case of flush mounting of these sensors.

[0017] Furthermore, a simple structure is achieved and therefore a cost-effective and automated production of the sensor is possible.

[0018] In addition, high temperature stability and long-term stability of the sensor can be achieved through this structure.

[0019] Furthermore, the influence of external magnetic fields on the switching behavior can be minimized.

[0020] Furthermore, for device variants with flush and non-flush mounting, a unique coil variant or coil plate can be provided for each sensor design. Thus, the same sensor components or electronic components can be used for various housing variants.

[0021] Furthermore, components, modules and platforms can be combined together to gain advantages in terms of logistics and procurement material costs or sensor manufacturing costs.

[0022] Possible improvements to the above method are described in detail below.

[0023] It can be provided that the polygonal shape of the first receiving coil is designed so that its vertices are at least partially arranged in the edge region of the coil plate. The width of this edge region can be, for example, at most two-tenths, preferably at most one-tenth, of the width of the coil plate. In this way, the largest possible coil diameter of the receiving coil is advantageously obtained at the corners of the polygon, so that a larger switching distance can be obtained.

[0024] The sides of the polygon are then further away from the edges of the coil plate and thus from the surrounding housing than the corners. Thus, in these regions of the coil, shielding or influence of the surrounding housing on the measurement signal is minimized.

[0025] It can be provided that the first receiving coil has a convex polygonal shape, in particular a regular convex polygonal shape. In this context, "convex" means that all internal angles are less than 180°. "Regular" here means that the polygon is equiangular. Alternatively, at least one angle can be greater than 180°, that is, the polygon can be at least partially concave, for example in the case of a star shape.

[0026] Optionally, the polygonal shape can have four sides and four inner angles, which are in particular symmetrical to one another and evenly distributed. Optionally, the first receiving coil has a rhombus shape, in particular a square shape.

[0027] The geometry of the receiving coil can be realized, for example, in the form of a rhombus or square, so that the coil diameter is maximum only at the four vertices, while at the sides a greater distance can be achieved from the surrounding metal of the housing, whether an internal metal shield or a metal mounting surface for the sensor. This therefore has no significant influence on the differential voltage to be analyzed.

[0028] Thus, a single coil plate can be used in order to be able to carry out this analysis and to achieve the switching distance to be detected by means of a special coil geometry for flush and non-flush sensor variants.

[0029] It can be provided that the transmitting coil has a perfect circular shape, wherein the transmitting coil optionally has the largest diameter that can be formed on the coil plate. That is, the diameter of the transmitting coil is designed to be as large as possible, in particular up to the edge or edge region of the coil plate. Thus, it can be achieved that the electromagnetic field of the transmitting coil is propagated with the largest possible effective range.

[0030] It can be provided that at least one second receiving coil is also provided. The first receiving coil and the second receiving coil can be arranged one above the other in a layered manner on the coil plate, wherein the first receiving coil and the second receiving coil are each designed with up to 3 layers in the case of a layered arrangement. Here, the transmitting coil is arranged between the first receiving coil and the second receiving coil, and the transmitting coil is calculated with multiple layers, in particular in the range of 1 to 5 layers. Furthermore, layers in the range of 3 to 5 can be provided.

[0031] The first receiving coil and the second receiving coil may each include a printed coil or be designed as a printed coil.

[0032] It may be provided that the first receiving coil and the second receiving coil have opposite winding directions.

[0033] In one example, it can be provided that for the first receiving coil, up to 3 layers with the same winding direction (i.e. the same direction with respect to the current flow) can be used. Subsequently, for the transmitting coil, up to 5 layers are provided, all with the same winding direction. Then, for the second receiving coil, up to 3 layers are provided, with a winding direction opposite to the first receiving coil. In addition, layers of shielding grids are provided to prevent radio frequency interference, layers for corresponding connecting printed conductors, and further layers for corresponding connecting cables of the electronic board.

[0034] It can also be provided that the coil plate stack has a total of 8 to 16 layers, in particular 8 to 14 layers, preferably 14 layers. The number of layers (e.g. 14 copper layers) can be designed so that the coil plate is not so complex and expensive, but still provides space for the copper layers for arranging the receiving coil and the transmitting coil. In addition, the complexity and expenditure of production, as well as the costs, depend to a large extent on the number of layers, and therefore the procurement costs are higher when the number of layers is greater. It is therefore advantageous that the coil plate is designed to be less complex and can also be used for both non-flush and flush installation situations.

[0035] The inductive proximity switch comprises a coil system according to the present description and a housing. Here, the coil system is arranged in or on the housing in a flush or non-flush manner.

[0036] The housing has a housing cross section, which is defined in particular along a plane spanned by the coil plate in the installed state.

[0037] In this case, the housing can be formed at least partially from metal. The coil arrangement can also be at least partially surrounded by metal in the circumferential direction in the installed state.

[0038] The housing cross section can be designed as a circle, for example. In addition, the receiving coil can be shaped as a square, for example, wherein the corners of the square extend substantially to the edge, ie, to a position close to the housing.

[0039] In another example, the housing cross section may be designed as a square. A square housing cross section may be particularly well suited for accommodating a square shape or an elongated rhombus shape of a receiving coil.

[0040] Alternatively, an elongated oval or rectangular housing cross section can also be provided, which is suitable, for example, for accommodating a receiving coil having a rhombus shape.

[0041] It can be provided that the receiving coil is arranged rotated 45° relative to the square housing cross section of the housing. The receiving coil can be designed as an elongated rhombus or square, so that the receiving coil has a larger diameter on the one hand (at the corners) and is away from the surrounding metal housing on the other hand. This is particularly evident when the receiving coil, in particular a square receiving coil, is oriented rotated 45° relative to the square housing cross section. As a result, the corners of the square of the coil are arranged close to the square housing, while a greater distance from the corners of the square housing cross section is obtained at the sides of the square of the coil.

[0042] In other words, the above description can be summarized into a possible more specific design of the present disclosure as described below, wherein the following description should not be regarded as limiting the present disclosure. The geometry of the coil can be adapted as required, so that non-flush and flush sensors with the required and market-standard switching distances can be realized with this coil design.

[0043] In order to be able to achieve this behavior, the transmitting coil is arranged in particular with the largest possible diameter on the coil plate, so that it can be ensured that the electromagnetic field propagates with the largest possible effective range.

[0044] The geometry of the receiving coil can be realized in a diamond shape, so that the coil diameter is maximum only at the four vertices, while at the sides a larger spacing is formed to the surrounding metal, both internal metal shielding and metal mounting surface to the sensor, without significant impact on the differential voltage to be analyzed.

[0045] Thus, the analysis and the switching distance to be detected can be realized with this special coil geometry and with only one coil plate for both flush and non-flush sensor variants.

[0046] The coil system can be adjusted and used in the corresponding installation situation without further prior adaptation. For example, two variants can be provided with respect to the installation geometry, namely a round installation or an angular installation.

[0047] In the case of cylindrical sensors, a front cover usually protrudes from the housing, which means that the sensor is not mounted flush in the housing, but can still be adjusted to a flush switching distance.

[0048] Two receiving coils can be provided, namely a receiving coil located in front of the transmitting coil and a receiving coil located behind the transmitting coil, the transmitting coil being thus arranged between the first receiving coil and the second receiving coil, wherein the coils are arranged one above the other to form a coil stack. The receiving coil can have, for example, 3 layers and, for example, 1.4 to 5 windings in each layer. The transmitting coil can have up to 5 layers, in particular in the range of 3 to 5 layers.

[0049] The transmitting coil can be designed as a circle. In each layer of the transmitting coil, for example, 4.0 to 5.0 windings are provided. It can be proposed that the windings of the circular transmitting coil are designed to be as wide as possible to make the resistance as low as possible. Therefore, the conductor tracks are closer to each other.

[0050] Due to the expansion in height, the entire stack of coils is limited to approximately 1.5 mm, for example, with 12 layers having coils.

[0051] In addition, a method for manufacturing a coil system of an inductive proximity switch is provided. The method has a plurality of method steps. In a first method step S1, at least one first receiving coil is formed on a coil plate by a layered arrangement, and in another method step S2, a transmitting coil is formed on the first receiving coil by a layered arrangement. Here, the transmitting coil has in particular a coil in the shape of a perfect circle. The first receiving coil includes a coil having a polygonal shape, in particular having four sides and inner angles, which are in particular symmetrical to each other and evenly distributed.

[0052] The method is particularly suitable for producing the coil system described here. The method therefore has corresponding advantages and can be developed in a similar manner as the coil system.

[0053] The above-mentioned designs and improvements can be combined with each other arbitrarily when it makes sense. Other possible designs, improvements and implementations of the present disclosure also include combinations of features previously or subsequently described with reference to the improvements of the present disclosure that are not explicitly mentioned. Here, those skilled in the art can also add individual aspects as improvements or supplementary contents to the corresponding basic form of the present disclosure. The features of the device claims can be implemented and / or implemented in particular by corresponding functions, thereby supplementing or expanding the method. In addition, the method steps can be implemented by corresponding implementation modules in the device. Therefore, the above-mentioned content described about the device is also similarly applicable to the method, and vice versa.

[0054] Further details and advantages of the invention will now be explained in greater detail with reference to an exemplary embodiment illustrated in the drawing. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In the attached picture:

[0056] Figures 1A to 1D A schematic diagram showing various layers of a coil system according to the present disclosure in an inductive proximity switch;

[0057] Figure 2 a schematic diagram showing layers in another inductive proximity switch; and

[0058] Figure 3 A flow chart showing a method according to the present disclosure is shown. DETAILED DESCRIPTION

[0059] The accompanying drawings should provide a further understanding of the disclosed improvements. They show the improvements and are used to explain the principles and concepts of the present disclosure in conjunction with the specification. Other improvements and many of the advantages mentioned are derived from the accompanying drawings. The elements in the drawings are not necessarily shown in proportion to each other.

[0060] In the figures, elements, features and components which are identical, have the same function and act in the same way are respectively provided with the same reference symbols unless otherwise specified.

[0061] refer to Figures 1A to 1D , a first embodiment of an inductive proximity switch 1 is described. The individual layers of the coil stack are shown only by way of example and schematically.

[0062] The inductive proximity switch 1 is provided for flush or non-flush installation in a housing 6. The housing 6 can be metallic or comprise a metallic material.

[0063] The maximum switching distances achieved for flush or non-flush mounting of inductive proximity switches (sensors) may be different. In this example, the maximum switching distance of a non-flush inductive proximity switch corresponds approximately to the coil diameter or housing diameter. The maximum switching distance of a flush inductive proximity switch corresponds approximately to half the diameter of the coil / housing.

[0064] The coil design of the proximity switch 1 is special in that, on the one hand, a larger switching distance can be adjusted for non-flush mounted inductive proximity switches, which have the property that the sensor component can be used in or on metallic environments, where otherwise only flush proximity switches can be used and the proximity switches continue to operate with their guaranteed properties.

[0065] If the proximity switch 1 is installed in a metallic sensor housing, for example for a flush cylindrical sensor variant, the sensor assembly can then be adjusted to the desired switching distance without requiring any additional work or measures.

[0066] The inductive proximity switch 1 , which is shown schematically here in a top view of a section through a housing 6 , has a coil plate 2 .

[0067] The coil plate 2 is designed to accommodate at least one first receiving coil 3 .

[0068] In this example, the first receiving coil 3 has a square shape, wherein the first receiving coil is arranged rotated 45° relative to the housing cross section which is also square. The first receiving coil has a maximum coil diameter at four vertices, i.e., these vertices extend to the edge of the printable area of ​​the coil plate 2. In addition, the first receiving coil forms a large spacing from the surrounding housing 6 at the four sides of the square, so that the influence of the surrounding housing 6 (in the case of flush mounting) on ​​the detected measurement signal is minimized.

[0069] The receiving coil 3 may be printed on the coil plate 2 .

[0070] The first receiving coil 3 may have a square shape or a rhombus shape or in particular a convex polygonal shape. The first receiving coil 3 comprises a coil designed as a polygonal shape, in particular having four sides and inner angles, which are in particular symmetrical and evenly distributed.

[0071] Here, a polygonal shape can also be understood more generally as a shape having corners at which the coil is arranged close to the surrounding housing 6 and edges at which a greater distance from the housing 6 is obtained, so that the housing 6 has a smaller influence on the measurement signal at this point.

[0072] In this example, a second receiving coil 4 is also provided which is formed substantially similarly to the first receiving coil 3 .

[0073] Furthermore, the coil system of the inductive proximity switch 1 has a transmitting coil 5 which is arranged in this example between the first receiving coil 3 and the second receiving coil 4 .

[0074] The transmitting coil 5 comprises a coil which is in particular in the shape of a perfect circle.

[0075] Furthermore, the transmitting coil 5 has the largest diameter that can be formed on the coil plate 2 , that is, the transmitting coil has the largest possible diameter within the printable area of ​​the coil plate 2 .

[0076] In this example, it is also proposed that the coil layer is provided with a grid 7 which shields the coil stack in a certain direction against electromagnetic interference or which shields the field generated by the transmitting coil in a certain direction.

[0077] exist Figures 1A to 1D The coil shapes and embodiments shown in FIG. 1 do not represent a restrictive configuration of the coil system of the inductive proximity switch 1 .

[0078] In particular, it is provided that the grid 7 , the first receiving coil 3 , the transmitting coil 5 and the second receiving coil 4 are arranged on top of each other on the coil plate 2 .

[0079] In this example, the first receiving coil 3 and the second receiving coil 4 are arranged in a layered manner.

[0080] The receiving coils 3 , 4 can each be designed with three layers, for example.

[0081] The first receiving coil 3 and / or the second receiving coil 4 may have a square shape or a rhombus shape; however, other shapes may also be provided for at least one of the receiving coils 3 , 4 .

[0082] A transmitting coil 5 may be arranged between the first receiving coil 3 and the second receiving coil 4 .

[0083] The transmitting coil 5 may be formed in the range of 3 to 5 layers.

[0084] In this example, the coil plate 2 of the embodiment of the inductive proximity switch 1 with the first and second receiving coils 3 , 4 can have 14 layers.

[0085] In particular, the first receiving coil 3 and the second receiving coil 4 have opposite winding directions.

[0086] In this example, the inductive proximity switch 1 has a housing 6 .

[0087] exist Figures 1A to 1D In the example shown in FIG. 5 , the housing 6 has a square housing cross section. In the square housing cross section, the first and second receiving coils 3 , 4 can be arranged in a square shape, a circular shape or a rhombus shape.

[0088] In the inductive proximity switch 1 Figure 2 In the alternative configuration shown, the housing 6 has a circular cross section. The coil plate 2 is also designed in a circular shape here. Only one layer of the first receiving coil 3 designed in a square shape is shown by way of example.

[0089] In this case, the corners are located at the edges of the printable area of ​​the coil plate 2 , while the sides of the square are at a greater distance from the housing 6 .

[0090] In this example, the first receiving coil 3 and the second receiving coil 4 are similar to Figure 2 The situation shown is designed such that a transmitting coil 5 is arranged between the first receiving coil 3 and the second receiving coil 4 .

[0091] In this example, the proximity switch 1 is formed in a manner similar to the above-described examples.

[0092] In other examples, the housing 6 can be designed to be in the shape of an elongated strip, an ellipse or a rectangle. In such an alternative design, the rhombus shape of the first receiving coil 3 and the second receiving coil 4 is particularly advantageous.

[0093] Figure 3 A flow chart of a method according to the present disclosure is shown. This is based on the above-described embodiments of a coil system or an inductive proximity sensor.

[0094] exist Figure 3 In the figure, reference symbol V refers to an embodiment of the method.

[0095] Method V for producing a coil arrangement of an inductive proximity switch 1 has a plurality of method steps.

[0096] In a first method step S1 , at least one first receiving coil 3 is formed in a layered arrangement on a coil plate 2 of an inductive proximity switch 1 (in particular by printing conductor tracks of the coil).

[0097] In a further method step S2, a transmitting coil 5 is formed in a layered design on the first receiving coil 3. The transmitting coil 5 comprises a coil which in particular has a perfect circular shape.

[0098] The first receiving coil 3 comprises a coil which is designed in a polygonal shape, in particular having four sides and inner angles, which are in particular symmetrical to one another and evenly distributed.

[0099] Furthermore, it is provided in a further method step S3 that a second receiving coil 4 is formed on the transmitting coil 5 in a layered design similar to the first receiving coil 3 .

[0100] In this example, the first receiving coil 3 , the second receiving coil 4 and the transmitting coil 5 are arranged one above the other.

[0101] Furthermore, further layers for the shielding grid, connecting conductor tracks and layers with connecting conductors for the electronic board can be provided.

[0102] By means of this arrangement of the coils, non-flush and flush proximity switches can be realized with the required and commercially available standard switching distances.

[0103] List of Reference Numerals

[0104] 1 Inductive proximity switch

[0105] 2 Coil Plate

[0106] 3. First receiving coil

[0107] 4 Second receiving coil

[0108] 5 Transmitter Coil

[0109] 6 Housing

[0110] 7 Grille

[0111] V Method

[0112] S1, S2, S3 Method Steps

Claims

1. A coil system for an inductive proximity switch (1) for flush or non-flush mounting in a housing (6), the coil system comprising: - a coil plate (2), on which at least one first receiving coil (3) and a transmitting coil (5) are arranged; - wherein the first receiving coil (3) comprises a coil designed in a polygonal shape.

2. The coil system according to claim 1, characterized in that The polygonal shape of the first receiving coil (3) is designed so that its vertices are at least partially arranged in the edge region of the coil plate (2).

3. The coil system according to claim 1, characterized in that The first receiving coil (3) has a convex polygonal shape, optionally a regular convex polygonal shape, optionally having four sides and four internal angles, wherein the sides and the internal angles are in particular symmetrical to each other and evenly distributed; Optionally, the first receiving coil (3) has a rhombus shape, in particular a square shape.

4. The coil system according to claim 1, characterized in that The transmitting coil (5) has a perfect circular shape; Optionally, the transmitting coil (5) optionally has a maximum diameter that can be formed on the coil plate (2).

5. The coil system according to any one of claims 1 to 4, characterized in that At least one second receiving coil (4) is also provided. The first receiving coil (3) and the second receiving coil (4) are arranged on the coil plate (2) in a layered manner and stacked one on top of the other. The first receiving coil (3) and the second receiving coil (4) are respectively designed with three layers when a layered arrangement is adopted, and The transmitting coil (5) is arranged between the first receiving coil (3) and the second receiving coil (4), and The transmitting coil (5) is designed with multiple layers, in particular in the range of 1 to 5 layers.

6. The coil system according to any one of claims 1 to 4, characterized in that The coil stack of the coil plate (2) has 8 to 16 layers, in particular 8 to 14 layers, preferably 14 layers.

7. The coil system according to claim 5, characterized in that The first receiving coil (3) and the second receiving coil (4) have opposite winding directions.

8. An inductive proximity switch (1), comprising a coil system according to one of claims 1 to 7 and a housing (6), wherein the coil system is arranged flush or non-flush in the housing (6), and the housing (6) has a housing cross section; Optionally, the housing is at least partially made of metal; Optionally, the coil arrangement is at least partially surrounded by metal in the installed state in the circumferential direction.

9. The inductive proximity switch (1) according to claim 8, characterized in that: The cross section of the shell is designed to be square or circular; Optionally, when the housing cross section is square, the receiving coil, in particular the square receiving coil, is arranged to be rotated 45° relative to the square housing cross section of the housing (6); or Optionally, when the cross section of the shell is circular, the receiving coil is rhombus-shaped or square-shaped.

10. A method for producing a coil system of an inductive proximity switch (1) according to claim 8 or 9, the method comprising the following method steps: - forming at least one first receiving coil (3) on the coil plate (2) by means of a layered arrangement; and - forming a transmitting coil (5) on the first receiving coil (3) by means of a layered arrangement, The transmitting coil (5) is particularly a coil in the shape of a perfect circle; and The first receiving coil (3) comprises a coil having a polygonal shape, in particular having four sides and inner angles, wherein the sides and the inner angles are in particular symmetrical to each other and evenly distributed.

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