Flush-mounted or non-flush-mounted coil systems of inductive proximity switches installed in a housing

Abstract

This 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 at least one first receiving coil and a transmitting coil are arranged. Here, the transmitting coil comprises a coil designed in a polygonal shape.

Description

Technical Field

[0001] This disclosure relates to a coil system for an inductive proximity switch mounted flush or non-flush in a housing. Furthermore, this disclosure relates to an inductive proximity switch having a coil system and a method for manufacturing the coil system. Background Technology

[0002] In the prior art, inductive sensors with wound coils are known, where the winding coils are housed in a ferrite core for orienting electromagnetic fields.

[0003] A particular challenge with sensor mounting is that the sensor must be flush-mounted into the housing and subsequently surrounded circumferentially by it. Metal housings, in particular, provide shielding, which significantly impacts the function of the receiver coil. Therefore, special sensor variants are typically constructed for flush mounting, where the receiver coil has a specific spacing from the surrounding housing. However, this results in a smaller diameter receiver coil and poorer detection characteristics in flush-mounted sensors compared to variants used for non-flush mounting.

[0004] The diameter of the ferrite core used in flush and non-flush sensors can vary considerably due to the space required for internal shielding of the coils in a flush device. This correlation also applies to the wound 3-cavity coil (3-Kammer-Spulen) of the Factor 1 sensor.

[0005] In Factor 1 sensors employing printed coils, the diameter of the printed coil used in the flush-mount sensor variant may also be smaller than that of the coil in the non-flush-mount sensor variant, or the former may require trimming of the compensation winding to be mounted in metal, which could prevent the achievement of the larger switching distances commonly found in the market for the non-flush-mount variant. Therefore, different coil boards exist for both flush-mount and non-flush-mount sensors in these sensors.

[0006] In the prior art, various design schemes for inductive sensors have been proposed. An inductive proximity sensor with transmitting and receiving coils detects the attenuation of the resonant circuit when it approaches a metallic object (which has corresponding magnetism) and switches when the switching distance is reached.

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

[0008] The common thread in known solutions is that their inherent geometry is often unsuitable for both flush and non-flush sensors with the required standard switching distance. Therefore, different sensor board variations must always be available for different mounting conditions. Summary of the Invention

[0009] In the context of the prior art, the purpose of this disclosure is to provide a coil system for an inductive proximity switch, an inductive proximity switch, and a method for manufacturing the coil system, which are adapted to at least partially overcome the aforementioned disadvantages of the prior art and enrich the prior art.

[0010] This objective is achieved through the features of the independent patent claims. The dependent claims, correspondingly, represent optional improvements to this disclosure.

[0011] Therefore, this objective is achieved by a coil system for an inductive proximity switch mounted flush or non-flush in a housing. The housing may, in particular, be designed as a metal housing or may comprise at least metal. The coil system has a coil plate on which at least one first receiving coil and a transmitting coil are arranged. Here, the first receiving coil comprises a coil designed in a polygonal shape.

[0012] The receiving and transmitting coils can be designed as printed coils. Furthermore, they can be arranged in a layered, stacked manner.

[0013] In the sense of this disclosure, a flush or fully flush mounted sensor can be understood as a sensor that is completely embedded in the surrounding material of the housing, particularly metal, up to the topmost sensor surface.

[0014] In the case of non-flush mounting of the sensor, free space is provided around the sensing surface. It is generally proposed that non-flush mounted sensors protrude from the housing, especially so that the coil is not surrounded by metal material.

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

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

[0017] Furthermore, a simple structure was obtained, which enabled cost-effective and automated manufacturing of the sensor.

[0018] Furthermore, this structure allows for high-temperature stability and long-term stability of the sensor.

[0019] In addition, it can minimize the influence of external magnetic fields on switching behavior.

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

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

[0022] The following section details possible improvements to the above method.

[0023] It can be proposed that the polygonal shape of the first receiving coil is designed such that its vertices are at least partially located 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, thereby achieving a larger switching distance.

[0024] Therefore, the sides of the polygon are farther from the edge of the coil plate and thus farther from the surrounding housing than the corners. Consequently, in these regions of the coil, the shielding or influence of the surrounding housing on the measurement signal is minimized.

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

[0026] Optionally, the polygonal shape may have four sides and four interior angles, which are particularly symmetrical and evenly distributed. Optionally, the first receiving coil has a rhomboid shape, particularly a square shape.

[0027] The geometry of the receiving coil can be, for example, a rhombus or a square, such that the coil diameter is largest only at the four vertices, while a larger gap can be achieved between the coil and the surrounding metal of the housing on the sides, whether it is the internal metal shielding or the metal mounting surface for the sensor. Therefore, it has no significant impact on the differential voltage to be analyzed.

[0028] Therefore, a unique coil board can be used so that this analysis and the switching distance to be detected can be achieved by means of special coil geometry for flush and non-flush sensor variants.

[0029] It can be proposed that the transmitting coil has a perfectly 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, especially up to the edge or edge region of the coil plate. Therefore, it is possible to make the electromagnetic field of the transmitting coil propagate over the largest possible effective range.

[0030] It can be proposed that at least one second receiving coil is also provided. The first and second receiving coils can be arranged in layers, stacked one on top of the other on the coil plate, wherein the first and second receiving coils are each designed with up to three layers when arranged in layers. Here, the transmitting coil is arranged between the first and second receiving coils, and the transmitting coil is designed with multiple layers, particularly in the range of 1 to 5 layers. In addition, layers in the range of 3 to 5 layers can be provided.

[0031] The first and second receiving coils may each comprise printed coils or be designed as printed coils.

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

[0033] In one example, it can be proposed that for the first receiving coil, up to three layers with the same winding direction (i.e., the same direction of current flow) can be used. Subsequently, for the transmitting coil, up to five layers with the same winding direction are provided. Then, for the second receiving coil, up to three layers with the winding direction opposite to that of the first receiving coil are provided. In addition, layers for shielding grids to prevent radio frequency interference, layers for corresponding connecting printed wires, and additional layers for corresponding connecting ribbon cables of the electronic board are also provided.

[0034] It can also be proposed that the coil board has 8 to 16 layers, particularly 8 to 14 layers, preferably 14 layers. The number of layers (e.g., 14 copper layers) can be configured to make the coil board less complex and expensive, while still providing space for the copper layers for arranging the receiving and transmitting coils. Furthermore, the complexity and cost of production, as well as the overall cost, depend heavily on the number of layers, and therefore, the procurement cost increases with a larger number of layers. Therefore, it is advantageous that the coil board is designed to be less complex and can be used for both flush and non-flush mounting applications.

[0035] An inductive proximity switch includes a coil system according to this specification and a housing. Here, the coil system is arranged flush or non-flush in or on the housing.

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

[0037] Here, the housing may be at least partially made of metal. The coil system may also be at least partially surrounded by metal in the circumferential direction when installed.

[0038] The cross-section of the housing can be designed to be circular, for example. Furthermore, the receiving coil can be shaped as a square, with the corners of the square extending substantially to the edge, i.e., to a position close to the housing.

[0039] In another example, the housing cross-section can be designed as a square. A square housing cross-section is particularly well-suited for housing square or elongated rhomboid shapes for receiving coils.

[0040] Alternatively, a slender elliptical or rectangular housing cross-section can be provided, for example, to accommodate a receiving coil with a rhomboid shape.

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

[0042] In other words, the above description can be summarized as a potentially more specific design of this disclosure as described below, wherein the following description should not be considered as a limitation of this disclosure. The geometry of the coil can be adapted as required, enabling the implementation of both flush and non-flush sensors with the required and commercially available standard switching distances using this coil design.

[0043] In order to achieve this behavior, the transmitting coil is set on the coil plate with the largest possible diameter, so as to ensure that the electromagnetic field propagates within the largest possible effective range.

[0044] The geometry of the receiving coil can be achieved in a rhombus shape, such that the coil diameter is largest only at the four vertices, while creating a larger gap between the coil and the surrounding metal on the sides, whether it is the internal metal shield or the metal mounting surface for the sensor, without significantly affecting the differential voltage to be analyzed.

[0045] Therefore, this analysis and the switching distance to be detected can be achieved using this special coil geometry and a single coil plate for both flush and non-flush sensor variants.

[0046] This coil system can be adapted and applied to the appropriate installation without requiring prior adaptation. For example, two variations can be provided for the installation geometry: circular or angular mounting.

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

[0048] Two receiving coils can be provided: one in front of the transmitting coil and one behind it. The transmitting coil is thus arranged between the first and second receiving coils, with these coils stacked vertically to form a coil pile. The receiving coil can, for example, have three layers, with 1.4 to 5 windings in each layer. The transmitting coil can have up to five layers, particularly in the range of three to five layers.

[0049] The transmitting coil can be designed to be circular. For example, 4.0 to 5.0 windings can be arranged in each layer of the transmitting coil. It can be proposed that the windings of the circular transmitting coil be designed to be as wide as possible to minimize resistance. Therefore, the printed wires are closer together.

[0050] Due to the increased height, the entire stack of coils is limited to approximately 1.5 mm, with 12 layers containing coils.

[0051] Furthermore, a method for manufacturing a coil system for an inductive proximity switch is provided. This method comprises several steps. In a first step S1, at least one first receiving coil is formed on a coil plate using a layered arrangement, and in another step S2, a transmitting coil is formed on the first receiving coil using a layered arrangement. Here, the transmitting coil is particularly a coil with a perfectly circular shape. The first receiving coil includes a coil having a polygonal shape, particularly having four sides and interior corners, which are particularly symmetrically and uniformly distributed.

[0052] This method is particularly suitable for manufacturing the coil systems described herein. Therefore, this method has corresponding advantages and can be improved in a similar manner as the coil systems.

[0053] The aforementioned design schemes and improvements can be combined with each other arbitrarily where meaningful. Other possible design schemes, improvements, and implementations of this disclosure include combinations of features not explicitly mentioned in the prior or subsequent descriptions of improvements in this disclosure. Those skilled in the art can also add individual aspects as improvements or supplements to the corresponding basic form of this disclosure. The features of the device claims can be implemented and / or carried out through corresponding functions, thereby supplementing or extending the method. Furthermore, the method steps can be implemented through corresponding implementation modules in the device. Therefore, the foregoing description of the device also applies similarly to the method, and vice versa.

[0054] Other details and advantages of the invention will now be explained in detail with the aid of embodiments shown in the accompanying drawings. Attached Figure Description

[0055] In the attached diagram:

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

[0057] Figure 2 A schematic diagram of a layer in another inductive proximity switch is shown; and

[0058] Figure 3 A flowchart of the method according to this disclosure is shown. Detailed Implementation

[0059] The accompanying drawings should provide a further understanding of the improvements made to this disclosure. They illustrate the improvements and serve to illustrate the principles and concepts of this disclosure in conjunction with the specification. Other improvements and many of the mentioned advantages are derived from the drawings. The elements in the drawings are not necessarily shown to scale.

[0060] In the accompanying drawings, identical, functionally identical, and operationally identical elements, features, and components are correspondingly given the same reference numerals unless otherwise described in detail.

[0061] refer to Figures 1A to 1D This paper describes a first embodiment of an inductive proximity switch 1. The individual layers of the coil stack are shown only illustratively and schematically.

[0062] The inductive proximity switch 1 is configured to be mounted flush-mounted or non-flush-mounted into the housing 6. The housing 6 may be metallic or comprise a metallic material.

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

[0064] The special feature of the coil design of proximity switch 1 is that, for non-flush-mounted inductive proximity switches, a larger switching distance can be adjusted. Non-flush-mounted inductive proximity switches have the following characteristics: the sensor assembly can be used in or on a metallic environment, where otherwise only a flush-mounted proximity switch can be used and the proximity switch continues to operate with its guaranteed characteristics.

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

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

[0067] The coil plate 2 is designed to receive 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 cross-section of the housing, which is also square. The first receiving coil has its maximum coil diameter at the four vertices, i.e., these vertices extend to the edges of the printable area of ​​the coil plate 2. Furthermore, the first receiving coil forms a large distance from the surrounding housing 6 at the four sides of the square, thereby minimizing the influence of the surrounding housing 6 (in the case of flush mounting) on ​​the detected measurement signal.

[0069] The receiving coil 3 can be printed on the coil board 2.

[0070] The first receiving coil 3 may have a square shape, a rhombus shape, or in particular a convex polygonal shape. The first receiving coil 3 includes a coil designed in a polygonal shape, in particular having four sides and interior angles, which are particularly symmetrical and evenly distributed with respect to each other.

[0071] Here, the polygonal shape can also be understood more generally as having: corners, where the coils are arranged close to the surrounding housing 6; and edges, where a larger distance from the housing 6 is obtained, so that the housing 6 has less influence on the measurement signal at these edges.

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

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

[0074] The transmitting coil 5 includes a coil that is particularly circular in shape.

[0075] Furthermore, the transmitting coil 5 has the largest possible 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 to prevent electromagnetic interference, or the grid shields the field generated by the transmitting coil in a certain direction.

[0077] exist Figures 1A to 1D The coil shape and implementation shown do not represent a limiting design scheme for the coil system of the inductive proximity switch 1.

[0078] Specifically, it is mentioned that the grid 7, the first receiving coil 3, the transmitting coil 5, and the second receiving coil 4 are arranged on the coil plate 2 in a stacked manner.

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

[0080] For example, receiving coils 3 and 4 can each be designed with 3 layers.

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

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

[0083] The transmitting coil 5 can 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 having a first receiving coil and second receiving coils 3, 4 can have 14 layers.

[0085] 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, housing 6 has a square housing cross-section. Within the square housing cross-section, the first receiving coil and the second receiving coils 3 and 4 can be configured as 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 to be circular. Only one layer of the first receiving coil 3, designed to be square, is shown as an example.

[0089] Here, the corner is located at the edge of the printable area of ​​the coil plate 2, while the side of the square has a larger gap with the housing 6.

[0090] In this example, the first receiving coil 3 and the second receiving coil 4 are similar Figure 2 The design is based on the situation shown. A transmitting coil 5 is arranged between the first receiving coil 3 and the second receiving coil 4.

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

[0092] In another example, the housing 6 can be designed as a long strip, an oval, or a rectangle. In such alternative designs, the rhomboid shape of the first receiving coil 3 and the second receiving coil 4 is particularly advantageous.

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

[0094] exist Figure 3 In the figures, reference numeral V indicates the implementation method.

[0095] The method V for manufacturing a coil system for an inductive proximity switch 1 has multiple method steps.

[0096] In the first method step S1, at least one first receiving coil 3 is formed on the coil plate 2 of the inductive proximity switch 1 by means of printing (in particular by printing the printed wires of the coil).

[0097] In another method step S2, a layered design is used to form a transmitting coil 5 on the first receiving coil 3. The transmitting coil 5 includes a coil that is particularly circular in shape.

[0098] The first receiving coil 3 includes a coil designed in a polygonal shape, particularly having four sides and interior angles, which are particularly symmetrical and evenly distributed with respect to each other.

[0099] Furthermore, in another method step S3, a layered design is proposed to form a second receiving coil 4 on the transmitting coil 5, 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 stacked one on top of the other.

[0101] In addition, additional layers can be provided for shielding grids, connecting printed conductors, and having connecting cables for electronic boards.

[0102] This coil arrangement allows for both flush and non-flush proximity switches with the required and market-standard switching distances.

[0103] List of reference numerals

[0104] 1. Inductive proximity switch

[0105] 2. Coil board

[0106] 3 First receiving coil

[0107] 4 Second receiving coil

[0108] 5. Transmitting coil

[0109] 6. Shell

[0110] 7. Grille

[0111] V Method

[0112] S1, S2, S3 Method Steps

Claims

1. An inductive proximity switch, comprising: - Casing; and - Coil system, - The coil system described therein includes a coil plate, at least one first receiving coil and a transmitting coil arranged on the coil plate; - Wherein the first receiving coil comprises a polygonal coil; - The coil system is mounted flush-mounted or non-flush-mounted in the housing; - The housing has a square housing cross-section suitable for receiving the coil system; and - Wherein the first receiving coil is arranged to rotate relative to the cross-section of the square housing, such that the corners of the polygonal shape are arranged closer to the housing than the sides of the polygonal shape.

2. The inductive proximity switch according to claim 1, characterized in that, The polygonal shape of the first receiving coil is designed such that its vertices are at least partially located in the edge region of the coil plate.

3. The inductive proximity switch according to claim 1, characterized in that, The first receiving coil has a convex polygonal shape.

4. The inductive proximity switch according to claim 1, characterized in that, The first receiving coil has a rhomboid shape.

5. The inductive proximity switch according to claim 1, characterized in that, The first receiving coil has a square shape.

6. The inductive proximity switch according to claim 1, characterized in that, The first receiving coil has a regular convex polygon shape.

7. The inductive proximity switch according to claim 6, characterized in that, The regular convex polygon shape has four sides and four interior angles, and the sides and interior angles are symmetrically and evenly distributed.

8. The inductive proximity switch according to claim 1, characterized in that, The transmitting coil has a perfectly circular shape.

9. The inductive proximity switch according to claim 8, characterized in that, The transmitting coil has a maximum diameter that can be formed on the coil plate.

10. The inductive proximity switch according to claim 1, further comprising: - At least one second receiving coil; - The first receiving coil and the second receiving coil are arranged on the coil plate in a layered, stacked manner. - Wherein the first receiving coil and the second receiving coil are each designed with 3 layers when they are arranged in a layered manner; - The transmitting coil is arranged between the first receiving coil and the second receiving coil; and - The transmitting coil described herein is designed with multiple layers.

11. The inductive proximity switch according to claim 10, characterized in that, The number of layers ranges from 2 to 5.

12. The inductive proximity switch according to claim 10, characterized in that, The first receiving coil and the second receiving coil have opposite winding directions.

13. The inductive proximity switch according to claim 1, characterized in that, The coil stack of the coil plate has 8 to 16 layers.

14. The inductive proximity switch according to claim 1, characterized in that, The coil stack of the coil plate has 8 to 14 layers.

15. The inductive proximity switch according to claim 1, characterized in that, The coil stack of the coil plate has 14 layers.

16. The inductive proximity switch according to claim 1, characterized in that, The shell is at least partially made of metal.

17. The inductive proximity switch of claim 16, wherein the coil system, in the installed state, is at least partially surrounded by metal in the circumferential direction.

18. A method for manufacturing an inductive proximity switch, the method comprising the following steps: - The coil system is manufactured using the following methods: - At least one first receiving coil is formed by layering on a coil plate; and - A transmitting coil is formed by layering the first receiving coil; - Wherein the first receiving coil comprises a polygonal coil; and - The coil system is mounted flush or non-flush in the housing; - The housing has a square housing cross-section suitable for receiving the coil system; and - Wherein the first receiving coil is arranged to rotate relative to the cross-section of the square housing, such that the corners of the polygonal shape are arranged closer to the housing than the sides of the polygonal shape.

19. The method according to claim 18, characterized in that, The transmitting coil includes a coil with a circular shape.

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