Protective device for sensors

Abstract

The present invention relates to a protective device (1) for a proximity sensor (6), comprising a housing (17) with an opening (4), via which the proximity sensor (6) can be inserted into the housing (17). The housing (17) is composed of at least one layer of a plastically or elastically deformable material, as a result of which the housing (17) is able to convert the impact energy, which acts on the housing (17) as a result of an impact, into deformation energy, so that the impact energy is not forwarded to the proximity sensor (6). This prevents damage to the proximity sensor (6).

Description

[0001] Protective device for sensors

[0002] The invention relates to a protective device for sensors according to the preamble of patent claim 1.

[0003] Sensors are components that can detect chemical or physical properties. Sensors are also used to qualitatively or quantitatively measure the material properties of an environment.

[0004] If sensors are to be used in potentially explosive atmospheres (areas with a risk of explosion), they must pass an impact test in which they are exposed to a specific impact energy, as ignition sources must be avoided in potentially explosive atmospheres. For this purpose, an impact test is carried out using an impact weight. If an impact test is conducted according to EN 60079-0 or IEC 60079-0, the impact is applied with an energy of 6.867 joules (= approximately 7 joules in common parlance). However, the impact can also be applied with a reduced energy of 3.924 joules (= approximately 4 joules in common parlance).

[0005] The desired impact and shock resistance of a sensor can be achieved by additional protective devices, such as damping and spring elements.

[0006] From DE 10 2012 223261 B4 and DE 10 2012 200 478 A1, such a proximity switch with an impact and shock absorption device is known. It comprises an upper part and a lower part. The upper part contains the components to be protected against impact and shock, and the lower part serves for attachment to a support surface. A damping element for dampening impacts and shocks is arranged between the upper and lower parts. Sensors with a protective device are also described, for example, in DE 20

[0007] 2013 973 U1 , DE 10 2018 120 978 A1 and DE 100 65 384 A1.

[0008] Furthermore, DE 10 2015221 312 B3 describes an inductive sensor with a cylindrical housing made of rigid material, which has a front cover, a cylinder tube and a rear plug with an electrical connection, as well as a first O-ring arranged between the front section and the cylinder tube, and a second O-ring, wherein the second O-ring is positioned by an annular groove in the front section and a support in the cylinder tube and is deformable by impact or shock on the front section, wherein the front section and the cylinder tube have corresponding front-side widenings serving as stops, wherein in the unloaded state an air gap is present between the first widening in the plug and the second widening in the cylinder tube, wherein a displacement path of the cover is determined by the width of the air gap,and wherein the displacement dampens the energy of a blow and / or impact.,

[0009] Finally, sensors are known from DE 102005 013 242 A1, DE 10 2021 206 893 A1 and DE 10 2020 106 829 A1 which have a housing made of a deformable material as a protective device.

[0010] However, the known protective devices are used for a very specific sensor and are therefore not universally applicable. Therefore, a specific protective device tailored to each sensor must be used.

[0011] The object of the present invention is to provide a protective device for sensors, wherein the protective device not only has improved impact and shock resistance, but is also suitable for sensors of different designs without the sensors having to be impact and shock resistant. This object is achieved according to the features of patent claim 1.

[0012] The invention thus relates to a protective device for a sensor, wherein the protective device has a housing with an opening. The sensor can be introduced into the housing of the protective device through this opening. As a result, the sensor is at least partially arranged in an interior space of the housing, whereby the sensor is at least partially surrounded by this protective device. As a result, the protective device surrounds at least the part (also referred to as the active surface) of the sensor that is exposed to the impact. The housing consists of at least one layer of a plastically or elastically deformable material. This at least one layer of the housing consists of a material that has a minimum deformability of at least 2% and a hardness in the range 10 Shore D to 100 Shore D. This at least one layer can also be reinforced by fibers and woven or braided fabrics made from these fibers.

[0013] If an impact is applied to the protective device during an impact test, the protective device can absorb the impact energy and convert it into potential deformation energy. This prevents damage to the sensor because the impact energy is not transmitted to the sensor. After the housing has been deformed by the impact, the housing returns to its original shape. This protective device can be used for various types of sensors, such as ultrasonic sensors, proximity sensors, or optical sensors.

[0014] The protective device can be constructed in one piece or in multiple parts. For example, it is possible to construct the protective device in two parts. In this case, the protective device consists of a first, front protective element and a second, rear protective element, so that the housing is formed by these two protective elements. This modular design makes it possible to accommodate sensors of different sizes in the protective device. If, for example, the size of the housing of a one-piece protective device is not sufficient to accommodate the active surfaces of a sensor in this protective device, an additional module can be attached to the housing of this protective device in order to enlarge the housing of this protective device.

[0015] In a particular embodiment, the protective device can have an internal thread in the interior of the protective device's housing. An inner sleeve can be arranged on this internal thread, to which a sensor can be attached. However, it is also conceivable for the corresponding sensor to be attached directly to this internal thread of the housing.

[0016] The inner sleeve has an external thread, allowing it to be attached to the internal thread of the housing via the external thread. Especially when the inner sleeve has at least one layer of elastically or plastically deformable material, this sleeve forms an additional impact protection element. It goes without saying that this at least one layer can also be reinforced with fibers.

[0017] A fastening device is provided inside the protective device, via which the sensor can be attached to the protective device. This fastening device can be designed, for example, as a spring-loaded suspension or a clamping element. The fastening device can also be an internal thread of the inner sleeve, allowing a sensor to be screwed to the internal thread of the inner sleeve.

[0018] Advantageously, a gap is arranged between the sensor, which is at least partially arranged in the housing of the protective device, and an inner wall of the housing, in which gap an impact protection element is located. This impact protection element has a minimum deformability of at least 2% and a hardness in the range of 10 Shore D to 100 Shore D. This impact protection element can be a foamed material. However, it is also possible to provide a gaseous medium (e.g., air) as an impact protection element in the gap.

[0019] As already explained, the housing of the protective device consists of at least one layer of a plastically or elastically deformable material. The material used is preferably a cross-linked elastomer, a thermoplastic elastomer, or a post-cross-linked thermoplastic elastomer. This at least one layer can also be reinforced with a fiber system. Instead of an elastomer, a metallic material with a face-centered cubic lattice structure (e.g., chromium-nickel steels, chromium-nickel-molybdenum steels, or chromium-manganese-molybdenum steels) can also be used.

[0020] For example, it's possible for the housing to consist of three layers arranged one above the other, with each layer made of a different elastomer. For example, only one layer, such as the middle layer, may be reinforced with a fiber system.

[0021] In another example, the housing may consist of two layers, with an inner layer, namely the layer facing the sensor, consisting of a post-crosslinked thermoplastic elastomer and the outer layer consisting of a metallic material with a face-centered cubic lattice structure (for example, a chromium-manganese-molybdenum steel or a chromium-manganese-molybdenum steel). The post-crosslinked thermoplastic elastomer may additionally be reinforced with fibers.

[0022] These materials are particularly well-suited for the protective device because they combine high deformability with sufficiently high rigidity (shear modulus, elastic modulus). If an impact is applied to the protective device, it deforms because these materials convert the impact energy into deformation energy. After deformation, the protective device returns to its original shape. Because the protective device converts the impact energy into deformation energy and thus does not transfer the impact energy to the sensor, damage to the sensor inside the protective device is prevented.

[0023] It is also explicitly proposed to combine several features of the individual described embodiments.

[0024] The present invention is explained in more detail below with reference to the accompanying drawings. They show:

[0025] Figure 1 is a perspective view of a first variant of a protective device for a sensor;

[0026] Figure 2 is a perspective view of an arrangement comprising the protective device according to Figure 1 and a sensor;

[0027] Figure 3 shows a longitudinal section through the arrangement of protective device and sensor shown in Figure 2;

[0028] Figure 4a is a perspective view of a second variant of a protective device for a sensor;

[0029] Figure 4b shows a section through the protective device shown in Figure 4a and

[0030] Figure 5 is a perspective view of a third variant of a protective device for a sensor.

[0031] Figure 1 shows a first variant of a protective device 1 for a sensor. The protective device 1 is designed in two parts and consists of a first, front protective element 2 and a second, rear protective element 3. The first, front protective element 2 and the second, rear protective element 3 together form a housing 17. The protective device 1 has an opening 4 in the rear protective element 3 into which a sensor (not shown) can be at least partially inserted into the protective device 1. The protective device 1 is thus designed as a protective hood. The front protective element 2 consists of at least one layer containing a material that is easily deformable and at the same time has high extensibility with sufficiently high rigidity (shear modulus, modulus of elasticity). This at least one layer can be reinforced by a fiber system.Materials that are suitable for this at least one layer are, for example, cross-linked elastomers (for example FKM (fluororubber), HNBR (acrylonitrile butadiene rubber) or EPDM (ethylene propylene diene rubber)), thermoplastic elastomers (such as TPE-E, TPE-O, TPE-A, TPE-II) or post-cross-linked thermoplastic elastomers (such as TPE-V). <Generell ist es aber auch möglich Stähle einzusetzen, insofern diese gut dehnbar sind, wie zum Beispiel metallische Werkstoffe mit kubisch flächenzentrierter Gitterstruktur (wie beispielsweise Chrom-Nickel-Stähle, Chrom-Nickel-Molybdän-Stähle, Chrom-Mangan-Stähle oder Chrom-Mangan-Molybdän-Stähle).

[0032] If the front protective element 2 consists of several layers, each of these layers can contain a different, easily deformable material, whereby each layer can in turn be reinforced by a fiber system. To allow a sensor (not shown) located in the protective device 1 to be installed in a device (not shown), such as an industrial plant, the protective element 2 has an external thread 5.

[0033] Materials that are easily deformable and simultaneously exhibit high elongation at break with sufficiently high rigidity (elastic modulus and shear modulus) are also suitable for the rear protective element 3. These materials can be plastically or elastically deformable.

[0034] Suitable materials include, for example, cross-linked elastomers (e.g., FKM (fluororubber), HNBR (acrylonitrile butadiene rubber), or EPDM (ethylene propylene diene rubber)), thermoplastic elastomers (such as, for example, TPE-E, TPE-O, TPE-A, TPE-II), or post-cross-linked thermoplastic elastomers (such as, for example, TPE-V). The rear protective element 3, like the front protective element 2, can consist of one or more layers of deformable material, with each layer being reinforced by a fiber system. In general, however, it is also possible to arrange a metallic material in a layer instead of an elastomer, provided that this metallic material is highly stretchable. Metallic materials with a face-centered cubic lattice structure are particularly well suited for this purpose. Such metallic materials can be, for example, chromium-nickel steels, chromium-nickel-molybdenum steels, chromium-manganese steels or chromium-manganese-molybdenum steels.

[0035] Both the front protective element 2 and the rear protective element 3 thus form active surfaces that can be subjected to an impact test. Together, the front protective element 2 and the rear protective element 3 form the housing 17, which at least partially surrounds the sensor (not shown in Figure 1). If an impact is exerted on the protective elements 2, 3 designed as active surfaces during an impact test, the corresponding active surface (protective element 2 or key element 3) is deformed by the impact energy acting on it because the active surface converts the impact energy into deformation energy. After the active surface has been deformed by the impact, this active surface can return to its original shape.

[0036] If only the front protective element 2 is to form an active surface, the rear protective element 3 can also be made of a different material, such as hard plastic.

[0037] The protective device 1 according to Figure 1 has an elongated design, making it particularly suitable for rod-shaped, for example cylindrical, sensors. However, the protective device 1 can also have other shapes. For example, the protective device can also be box-shaped, for example cube-shaped, so that a box-shaped sensor can be inserted into such a protective device 1. The only important thing with these protective devices is that they surround the part of a sensor to which an impact can be exerted during an impact test. These protective devices prevent the impact from being applied directly to the sensor. Since the protective device consists of at least one layer of a deformable material, the protective device can convert the impact energy into deformation energy, thereby preventing the impact energy from being passed on to the sensor and the sensor from being damaged by the impact.To ensure a sensor is securely seated in the protective device 1, the protective device 1 has a fastening device (not visible in Figure 1) inside the housing 17, with which a sensor can be fixed in the protective device 1. Such fastening devices can be clamps, plug connections, or a thread. This thread can be engaged with a mating thread of the sensor.

[0038] Figure 2 shows the two-part protective device 1 according to Figure 1, in which a rod-shaped sensor (not visible because it is located inside the protective device 1) is arranged. A plug connection 19 with an electrical connection 7 is attached to the sensor, which is at least partially arranged in the rear protective element 3 of the protective device 1. For this purpose, the sensor was pushed into the opening 4 so that the sensor sits in the protective device 1. The sensor and the protective device 1 together form an assembly 8. Since the sensor is surrounded by the protective device 1, it is not necessary for the sensor to consist of a housing made of deformable material because the protective device 1 already consists of at least one layer of such a material that is easily deformable and at the same time has high extensibility with sufficiently high rigidity (shear modulus, elastic modulus).If the protective device 1 is thus subjected to an impact test, the protective device 1 absorbs the impact energy completely, so that the impact energy is not passed on to the sensor arranged in the protective device 1. This protective device 1 therefore prevents the sensor from being damaged in the event of an impact. Figure 3 shows a longitudinal section through the arrangement 8 shown in Figure 2, consisting of the protective device 1 and the sensor 6 arranged therein. The plug connection 19 with the electrical connection 7 is attached to the sensor 6. The specific structure of the sensor 6 will not be discussed in detail below, because the sensors that can be arranged on the protective device 1 can also be already known sensors. The only important thing about the sensors is that they are rod-shaped so that they can be attached to the protective device 1 using a fastening device.It is not necessary for the sensors to be cylindrical, as in this embodiment.

[0039] The sensor 6 is inserted with a front side 9 up to a front section 10 of the first protective element 2 of the protective device 1 designed as a protective hood. The front section 10 is curved in the direction of the sensor 6, so that a test body 41 cannot touch this curved area upon impact on the front side 10 without first deforming the first protective element 2. This curved area thus additionally prevents the test body 41 from coming into direct contact with the front section 9 of the sensor 6 upon impact.

[0040] The rear protective element 3 is screwed into the front protective element 2. An inner sleeve 11 is arranged in the interior 18 of the protective device 1. This inner sleeve 11 has an external thread 12, via which the inner sleeve 11 can be screwed to an internal thread 13 of the protective device 1. This internal thread 13 is at least partially arranged on the rear protective element 3 and on the front protective element 2. It is understood that this internal thread 13 can also be provided only on the front protective element 2 or only on the rear protective element 3.

[0041] The inner sleeve 13 additionally has a fastening device to which the sensor 6 can be fastened in the protective device 1. In this exemplary embodiment, the fastening device is designed as an internal thread (not visible) which is arranged in an interior region of the inner sleeve 11, whereby the sensor 6 can be screwed into the protective device 1. For this purpose, the sensor 6 has an external thread (not visible). Such sensors with an external thread are known. However, these sensors are no longer screwed directly into a device, for example into an industrial plant, but rather the protective device 1 with the sensor arranged therein is screwed into such a device. Such a device is not shown in Figure 3 for the sake of clarity.

[0042] In order for the protective device 1 to be fastened in the device, the protective device 1 has the external thread 5 so that the arrangement 8 comprising the protective device 1 and the sensor 6 can be easily arranged in such a device or removed again.

[0043] It is, of course, also conceivable that the sensor 6 is attached directly to the internal thread 13. In this case, the sleeve 11 can be omitted. However, the advantage of the sleeve 11 is that it serves as an additional impact protection element—especially if the sleeve 11 consists of at least one layer of a deformable material—which is why it is advantageous to provide this inner sleeve and not attach the sensor 6 directly to the internal thread 13, which would of course also be possible.

[0044] So that the active surfaces, i.e. the rear protective element 3 or the front protective element 2, can deform in the direction of the sensor 6 without coming into contact with this sensor 6 during the deformation, a gap 15 is provided - as additional impact protection - at least partially between the sensor 6 and an inner wall 14 of the protective device 1. This gap 15 is provided in particular where the impact test is carried out using the impact test specimen. This gap 15 is filled with an additional impact protection element 16. This additional impact protection element 16 is preferably a gas (for example air or an inert gas) or a foamed material (for example foam resin). A gas is therefore well suited as an impact protection element 16 because it is compressible. The foamed material advantageously has a minimum deformability of at least 2%.Foamed materials with a hardness in the range of 10 Shore D to 100 Shore D are particularly suitable. In addition to the minimum requirement of good extensibility, such materials also exhibit sufficiently high material rigidity (elastic modulus and shear modulus). This impact protection element 16 can thus also convert the impact energy into deformation energy. This ensures that when the active surface of the protective device 1 deforms toward the sensor 6, the deformation energy is transferred to the impact protection element 16, which can also deform. This prevents both the housing 17 of the protective device 1 and the impact protection element 16 from transferring the impact energy to the sensor 6 and damaging it.Because the protective device 1 ultimately also serves as an impact protection element, the protective device 1 can be regarded as the first impact protection element 1 and the impact protection element 16 as the second impact protection element 16.

[0045] It is particularly advantageous if the inner sleeve 11 also consists of at least one layer made of a material that is easily deformable and, at the same time, has a high elongation at break with sufficiently high rigidity (elastic modulus and shear modulus). This at least one layer of the inner sleeve 11 can also be reinforced by a fiber system if this at least one layer consists of an elastomer. This allows the inner sleeve 11 to also absorb the deformation energy of the active surface of the protective device 1, thus preventing damage to the sensor 6. After the inner sleeve 11 has absorbed the impact energy transmitted to it from the active surfaces and has thus deformed, the inner sleeve 11 can return to its original shape. In this case, the sleeve 11 represents an additional, third impact protection element.

[0046] Figure 4a shows a protective device 20 that is constructed in one piece, whereby the protective device 20 also simultaneously forms the housing. This protective device 20 is made of a material that is easily deformable and simultaneously exhibits high elongation at break with sufficiently high rigidity (elastic modulus and shear modulus). Suitable materials for the protective device 20 include, for example, cross-linked elastomers (for example, FKM (fluororubber), HNBR (acrylonitrile butadiene rubber), or EPDM (ethylene propylene diene rubber)), thermoplastic elastomers (such as TPE-E, TPE-O, TPE-A, TPE-II), or post-cross-linked thermoplastic elastomers (such as TPE-V). These elastomers can be additionally reinforced with a fiber system.Steels can also be used, provided they are highly ductile, as is the case with metallic materials with a face-centered cubic lattice structure (such as chromium-nickel steels, chromium-nickel-molybdenum steels, chromium-manganese steels, or chromium-manganese-molybdenum steels). This protective device 20 can also consist of one or more layers of deformable material.

[0047] The protective device 20 has an external thread 21 with which the protective device 20 can be screwed into a device, for example, an industrial plant. Such a device is not shown in Figure 4.

[0048] Opposite a front section 22 of the protective device 20, an opening 23 is provided into which a sensor can be inserted. A fastening device for attaching the sensor is arranged in an interior region of the protective device 20. This fastening device is shown in Figure 4b. There, a section through the protective device 20 shown in Figure 4a is shown. The fastening device 26 comprises several threaded retaining webs 37 to 40, which are engaged with a housing 27 of the sensor 28 arranged in the protective device 20. The threaded retaining webs 37 to 40 are so narrow that they allow a certain axial deformation of the protective device 20 like a spiral spring. The threaded retaining webs 37 to 40 thus form an impact protection element. As can be seen in Figure 4b, the threaded retaining webs 37 to 40 bridge a gap 42 which is located between the sensor 28 and the protective device 20.This gap 42 is filled with a gas, such as air. Because the gas is compressible, it forms an additional impact protection element.

[0049] This allows the sensor 28 to move relative to the protective device 20 in the event of an impact, thus preventing the impact energy from being transmitted to the sensor 28 and damaging the sensor 28.

[0050] The protective device 20 has a spiral-shaped notch 24 extending in the longitudinal direction A, which is designed as a spiral-shaped gap 24. If an impact is applied to the front section 22 of the protective device 20, the notch 24 formed as a gap forms an additional impact protection element because the protective device 20 can deform into the notch 24. Instead of this spiral-shaped notch 24, several transversely extending notches can also be provided, which can be arranged either parallel to one another or offset from one another. Such an arrangement comprising several transversely extending notches is not shown.

[0051] The front section 22 of the protective device 20 is also curved in the direction of the sensor 28, so that a test specimen (not shown) cannot touch this curved area upon impact to the front side 22 without first deforming the protective device 20. This curved area thus additionally prevents the test specimen from coming into direct contact with a front section 29 of the sensor 28 upon impact.

[0052] Figure 5 shows a further variant of a protective device 30, which has a housing 43 with an opening 31. This protective device 30 is suitable for box-shaped sensors, which are at least partially inserted into the protective device 30 via the opening 31. In an interior 44 of the protective device 30 there is a fastening device (not visible) for a sensor (also not shown), wherein this fastening device can be designed, for example, as a spring suspension or as a clamping element. The protective device 30 consists - like the other protective devices 1, 20 - of at least one layer made of a plastically or elastically deformable material. This at least one layer can also be reinforced by a fiber system if necessary.Suitable materials for the protective device 30 include, for example, cross-linked elastomers (e.g., FKM (fluororubber), HNBR (acrylonitrile butadiene rubber), or EPDM (ethylene propylene diene rubber)), thermoplastic elastomers (such as TPE-E, TPE-O, TPE-A, TPE-II), or post-cross-linked thermoplastic elastomers (such as TPE-V). Steels can also be used, provided they are highly extensible, such as metallic materials with a face-centered cubic crystal structure. Such metallic materials include, for example, chromium-nickel steels, chromium-nickel-molybdenum steels, chromium-manganese steels, or chromium-manganese-molybdenum steels.

[0053] All of these materials can absorb the impact energy of an impact during an impact test and convert it into deformation energy. As a result, the protective device 30 deforms briefly but then returns to its original shape.

[0054] The protective device 30 has a plurality of webs 32, 33, 34, each with a passage 35, 36 through which a connecting means can be passed to attach the protective device 30 with the sensor mounted therein to an industrial system or other device (not shown). In this case, the protective device 30 comprises four webs, with only the three webs 32, 33, 34 being visible. These webs form an impact protection element.

[0055] This is advantageous because protective devices can be provided in which a sensor can be at least partially installed, without requiring the required impact resistance, allowing these protective devices to be used universally. Another advantage is that the protective devices can have various shapes, allowing sensors of a wide variety of designs to be installed in the correspondingly designed protective devices. Adapting a protective device to a specific sensor is thus no longer necessary.

[0056] All of these protective devices comprise at least one layer of deformable material, which can be plastically or elastically deformed. The at least one layer can be additionally reinforced with fibers, with suitable materials for such fibers being, for example, polyarylamides, aramids, or even polyethylene, as well as fabrics or braids made from these fibers. Steel fibers can also be used, provided they are not inductive proximity sensors.

[0057] The housing of these protective devices can be constructed in one or more parts. For example, as is the case with protective device 1, it is possible to construct the housing 17 in two parts.

[0058] List of reference symbols

[0059] protective device

[0060] protective element

[0061] protective element

[0062] opening

[0063] external thread

[0064] sensor

[0065] Electrical connection

[0066] arrangement

[0067] Front

[0068] Front section

[0069] Inner sleeve

[0070] external thread

[0071] internal thread

[0072] inner wall

[0073] gap

[0074] Impact protection element

[0075] Housing

[0076] Interior

[0077] Plug connection

[0078] protective device

[0079] external thread

[0080] Front section of the protective device 20

[0081] Opening Spiral Gap

[0082] Interior

[0083] Fastening device

[0084] Housing

[0085] sensor

[0086] Front section of the sensor 28

[0087] protective device

[0088] opening

[0089] web

[0090] web

[0091] web

[0092] Implementation

[0093] Implementation

[0094] Thread retaining web

[0095] Thread retaining web

[0096] Thread retaining web

[0097] Thread retaining web

[0098] Test specimen

[0099] gap

[0100] Housing

[0101] Interior

Claims

Patent claims 1. A protective device (1, 20, 30) for a sensor (6), comprising a housing (17, 43) with an opening (4, 23, 31) through which the sensor (6) can be inserted into the housing (17, 43), wherein the housing (17, 43) has at least one layer of a deformable material, characterized in that the deformable material has a minimum deformability of at least 2% and a hardness in the range from 10 Shore D to 100 Shore D.

2. Protective device (1, 20, 30) according to claim 1, characterized in that the housing (17, 43) of the protective device (1, 20, 30) is designed in one part or in several parts.

3. Protective device (1) according to claim 2, characterized in that the housing (17) of the protective device (1) is constructed in two parts, wherein the housing (17) consists of a first, front protective element (2) and a second, rear protective element (3).

4. Protective device (1) according to claim 1, characterized in that an internal thread (13) is arranged in an interior space (18) of the housing (17) of the protective device (1).

5. Protection device (1) according to claim 4, characterized in that an inner sleeve (11) is arranged in the interior (18) of the housing (17), which inner sleeve has an external thread (12), so that the inner sleeve (11) is fastened to the internal thread (13) of the housing (17) via the external thread (12).

6. Protection device (1, 20, 30) according to claim 1, characterized in that a fastening device is arranged in the interior (18, 44) of the housing (17, 43), via which a sensor in the Protective device (1, 20, 30) can be attached.

7. Protective device (1) according to claim 5 and 6, characterized in that the fastening device is an internal thread of an inner sleeve (11).

8. Protective device (20, 30) according to claim 6, characterized in that the fastening device is a clamping element or that the fastening device is at least one web (32 to 34).

9. Protective device (1) according to claim 1, characterized in that a gap (15) is arranged at least partially between the sensor (6) and an inner wall (14) of the protective device (1), wherein an impact protection element (16) is arranged in the gap (15).

10. Protection device (1) according to claim 9, characterized in that the impact protection element (16) is a gas, at least one web (32 to 34) or a foamed material.

11. Protective device (1) according to claim 10, characterized in that the foamed material has a minimum deformability of at least 2% and a hardness in the range from 10 Shore D to 100 Shore D.

12. Protective device (1, 20, 30) according to claim 1, characterized in that the material of the at least one layer of the housing (17, 43) is a cross-linked elastomer, a thermoplastic elastomer, a post-cross-linked thermoplastic elastomer or a metallic material with a cubic face-centered lattice structure.

13. Protective device (20) according to claim 1, characterized in that at least one notch (24) in the protective device (20) forms an impact protection element (24).

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