Vibration sensor

Abstract

The invention relates to a vibration sensor. A transducer device (2) excites a mechanically oscillating unit (1) to mechanical vibrations and / or receives mechanical vibrations from it. The invention consists in the fact that the transducer device (2) and a temperature sensor (3) form a single component.

Description

[0001] The invention relates to a vibration sensor having the features of the preamble of the first claim.

[0002] Vibration sensors are known in the art, for example, in the form of tuning forks or single rods. Such sensors have a mechanically vibrating unit that is excited to mechanical vibrations by a drive / receiver unit. The vibrations resulting from the interaction with a medium to be measured or monitored are received by the drive / receiver unit and processed. For measurement purposes, it is used, for example, that the vibration frequency or amplitude changes when the mechanically vibrating unit transitions from an uncovered to a state covered by the medium. This allows, for example, the monitoring of the fill level of the medium in a container.

[0003] The drive / receiver unit typically contains a transducer device that converts between electrical signals and mechanical vibrations. Piezoelectric elements are often used for this purpose; these elements have a polarized ceramic surface and at least one electrode on one end face for electrical contact. To increase the generated mechanical force, it is known to arrange several piezoelectric elements in a stack.

[0004] The properties of the medium in which the mechanically vibrating unit is embedded, and whose properties the vibration sensor is intended to monitor and / or determine, can be temperature-dependent. Therefore, determining the temperature of the medium is crucial for accurate parameter measurement. Furthermore, it should be noted that the transducer device typically contains multiple piezoelectric elements, which can be damaged by high temperatures, particularly above the Curie temperature. Therefore, it is known to use temperature sensors for determining and monitoring the temperature; see, for example, DE 10 2022 133 730 A1. In this case, the temperature sensor is integrated into the vibration sensor.

[0005] One problem is to accurately measure the temperature acting on the mechanically oscillating unit.

[0006] The object underlying the invention is therefore to propose a vibration sensor with a temperature sensor that allows for the most optimal and reliable temperature measurement possible over the period of application.

[0007] The problem is solved by combining the transducer device and the temperature sensor into a single component. The invention thus consists of integrating the transducer device and the temperature sensor into a cohesive unit. This also simplifies manufacturing. Furthermore, the transducer device is positioned in close proximity to the mechanically vibrating unit within the vibration sensor, which correspondingly influences the positioning of the temperature sensor. The transducer device and the temperature sensor therefore complement each other to form the complete component, or are at least partially complementary to one another, preferably with regard to their geometry. A temperature sensor is required, for example, when measurements are to be taken at high temperatures (e.g., between 150 °C and 230 °C).Temperature measurements are particularly helpful when the density of a medium needs to be measured or monitored at high temperatures.

[0008] One embodiment consists in the transducer device having a continuous recess, the temperature sensor being essentially mushroom-shaped, comprising an elongated base body and a support component arranged at its end face and designed as a partial sphere, the base body being at least partially arranged within the recess, and the support component being arranged outside the recess. In this embodiment, the transducer device has a continuous recess or hole in which the elongated base body of the temperature sensor, corresponding to the continuous recess, is located. The temperature sensor projects beyond the transducer device by means of a support component, which thus forms an end face of the temperature sensor and connects accordingly to the elongated base body.The mounting component thus also forms an end face of the combined component consisting of the transducer device and the temperature sensor. Depending on the design, the mounting component can be rounded or, for example, terminate in a flat surface. Essentially, the mounting component is characterized by its shape resembling a partial sphere. If the transducer device is positioned relative to the mechanically vibrating unit to transmit or receive the mechanical vibrations, the temperature sensor is also located near the vibrating unit to detect the temperature acting upon it.

[0009] One embodiment provides that the transducer device and the temperature sensor are designed and coordinated such that the maximum radial extent of the support component is essentially equal to the maximum radial extent of the transducer device. Thus, if the support component projects axially beyond the transducer device, it also spans radially across an end face of the transducer device in this embodiment. Therefore, in this embodiment, the support component forms the entire end face of the transducer device.

[0010] One embodiment includes the transducer device having at least one lateral recess, the temperature sensor having at least one elongated base body and a support component arranged at its end face, the base body being at least partially arranged in the recess, and the support component forming an end face of the overall component consisting of the transducer device and the temperature sensor. In one of the aforementioned embodiments, the temperature sensor's base body extends through the transducer device. In this embodiment, the temperature sensor flanks the transducer device laterally and, together with its support component, forms an end face of the overall component. Mechanical cohesion is achieved by the elongated base body being located in the lateral recess of the transducer device.

[0011] In a supplementary embodiment, the temperature sensor has a second elongated base body. In one embodiment, this second base body contains an additional sensor. In another embodiment, the two base bodies are positioned diametrically opposite each other on the mounting component. In one variant, the transducer device is thus enclosed on two sides.

[0012] In one design, the base body is essentially designed as a rod or column. In one variant, the base body and the support component are either a single piece or, alternatively, multi-piece.

[0013] One embodiment includes a temperature sensor comprising at least one elongated base body and a mounting component arranged at its end face, where the base body at least partially encloses the transducer device, and the mounting component forms an end face of the overall component consisting of the transducer device and the temperature sensor. In this embodiment, the base body at least partially encloses the transducer device. The base body is therefore partially sleeve-like. Depending on the specific embodiment, the transducer device arranged within the base body is partially or completely enclosed laterally.

[0014] One embodiment of the transducer device consists of several piezoelectric rings arranged in a stack, each ring having an electrode on its end face that extends to the opposite end face. In this embodiment, the transducer device has piezoelectric rings with double contact. The piezoelectric elements have two end faces, with the polarization oriented from one end face to the other. Each end face has an electrode—preferably metallic—for electrical contact, i.e., for applying and / or receiving electrical signals. The electrodes extend to the opposite end face, for example, via the side surface. Therefore, both electrodes are present on each of the two end faces.The advantage of this re-contacting method is that a contact electrode, also known as a solder lug, can be omitted. This is particularly beneficial for applications involving high temperatures – for example, between 150 °C and 230 °C.

[0015] Depending on the design, the piezo ring or piezo rings can have a circular, square or rectangular outer contour.

[0016] One embodiment provides that the transducer device has two contact lines, and that one of the two contact lines is routed within the recess and the other outside the stack of piezoelectric rings. In this embodiment, two contact lines are sufficient to supply the transducer device with electrical signals and / or to tap them. Therefore, the individual piezoelectric rings are preferably in contact with each other. To minimize the risk of a short circuit and to ensure the safest possible manufacturing process, the two contact lines are positioned as far apart as possible. Thus, one line is routed within the recess and the other line is routed outside the recess.

[0017] One embodiment of the temperature sensor comprises a sensor element and a ceramic body, with the sensor element located inside the ceramic body. The sensor element is, for example, an electrical resistance element whose electrical resistance allows the temperature to be determined. The sensor element is arranged within a ceramic body. The ceramic body preferably has the shape of the elongated base body and the mounting component. In one embodiment, the material of the ceramic body is essentially the same as that of the piezoelectric elements.

[0018] One embodiment provides that the vibration sensor has a diaphragm, that the mechanically vibrating unit is arranged on the diaphragm, and that the mounting component of the temperature sensor rests on the diaphragm. In this embodiment, the temperature sensor is located in optimal proximity to the mechanically vibrating unit. Furthermore, the temperature sensor is located at the point of force transmission between the diaphragm and the transducer device. The mounting component also helps to transmit the force of the transducer device as efficiently as possible.

[0019] One embodiment consists of the mechanically oscillating unit being a rocker fork.

[0020] In one embodiment, the invention relates to a vibration sensor with any sensor, which forms a complete component with a transducer device. The embodiments then apply accordingly.

[0021] The invention is explained in more detail with reference to the following figures. Fig. Figure 1 shows a schematic cross-sectional view of a vibration sensor. Fig. 2 shows the two end faces ( Fig. 2 a) and Fig. 2 b)) of a piezoelectric ring, Fig. Figure 3 shows a schematic section through a temperature sensor and a converter device according to a first variant. Fig. Figure 4 shows the unit consisting of the temperature sensor and converter device. Fig. 3, Fig. 5 shows an overall component according to a second variant, Fig. Figure 6 shows a top view of the overall component of the Fig. 5, Fig. Figure 7 shows a section through a schematic overall component according to a third variant and Fig. Figure 8 shows a top view of the third variant of the overall component of the Fig. 7.

[0022] The Fig. Figure 1 shows a so-called vibrating fork as an example of a vibration sensor design. The mechanically vibrating unit 1 has two so-called fork tines connected to a diaphragm 4. On the opposite, and therefore inner, side of the diaphragm 4, a transducer device 2 is located in a housing 5 (indicated here). This transducer device consists of several disc-like piezoelectric elements 21 arranged in a stack (see Figure 1). Fig. 2) The transducer device 2 rests with the temperature sensor 3 on the diaphragm 4 and is pressed against the diaphragm 4 by a pressure screw 6. An electronic unit – not shown here – is provided for exciting the vibrations and for evaluating the vibrations and the measurement signals from the temperature sensor 3.

[0023] The illustration Fig. Figures 2 a) and b) show the two end faces 210 of a disk-shaped piezoelectric ring 21 with double re-contacting. This means that the two electrodes 211 located on the end faces 210 are each connected via the outer surface to the opposite end face 210. The outer and inner circular rings thus each belong to the electrode 211 of the other end face 210. In the exemplary embodiment of the piezoelectric ring 21, the re-contacting extends over the entire inner and outer surface of the disk. Alternatively, the re-contacting – not shown here – occurs over a significantly limited section.

[0024] The example of the piezo ring 21 of the Fig. 2 has a circular outer shape, although the piezo rings can alternatively be square, for example.

[0025] The illustrations Fig. 3 and Fig. Figures 4 each show a unit consisting of a converter device 2 and a temperature sensor 3 - once in the separated state ( Fig. 3) and once as a combined unit ( Fig. 4) Both illustrations will be discussed together.

[0026] The mushroom-shaped form of the temperature sensor 3 is visible, resulting from the elongated base body 30 and the end-face mounting component 31. A sensor element 32, which is a temperature-dependent resistance element, is located within the single-piece ceramic body 33. Two lines 34 are provided for acquiring the temperature-dependent measured value.

[0027] The transducer device 2 consists of several piezo rings 21, which are arranged in a stack and each is separated from the others by the Fig. The double re-contact connection described in section 2 is electrically connected. Therefore, two contact lines 22 are sufficient for actuating the stack of piezo rings 21, one of which is led out of the recess 20 and the other is routed laterally.

[0028] In the Fig. Figure 4 clearly shows how the base body 30 of the temperature sensor 3 is located in the recess 20. It can also be seen that the support component 31, with its maximum outer circumference, spans one end face of the transducer device 2. Furthermore, it can be seen that the temperature element 32 is located in close proximity to the membrane 4 (see Figure 4). Fig. 1).

[0029] The cut of the Fig. 5 and the top view of the Fig. Figure 6 shows another variant of the overall component consisting of converter device 2 and temperature sensor 3 and illustrates the positioning of the elongated base body 30 laterally to the converter device 2.

[0030] In the example of the Fig. 5 and Fig. 6 is the basic body 30 as column- or rod-like as in the example of the Fig. 3 and Fig. 4. The base body 30 is located here in a lateral recess 20 of the piezoelectric discs that form the transducer device 2. The sensor element 32 is located in the base body 30. The support component 31 is also semicircular in shape and merges seamlessly into the base body 30.

[0031] In the variant of the overall component, which is from the Fig. 7 and the Fig. As shown in Figure 8, the transducer device 2 is flanked laterally by two base bodies 30, each located in a lateral recess 20 of the piezoelectric discs of the transducer device 2. The piezoelectric discs of the transducer device 2 are in the variant of Fig. 7 and Fig. 8 - as in the variant of Fig. 5 and Fig. 6 - each flat disc without an inner hole like the rings of the variant of Fig. 3 and Fig. 4.

[0032] The two column-like base bodies 30 are diametrically opposed to each other and have - as particularly evident at the Fig. 8 can be identified - differently sized base areas. Fig. Figure 7 indicates that each of the two base bodies 30 contains a sensor element 32. In one embodiment, these are two temperature sensors. In an alternative embodiment, a temperature sensor and another sensor element, e.g., a humidity sensor, are combined. Reference symbol list 1 mechanically oscillating unit 2 Converter device 3 Temperature sensor 4 membranes 5 cases 6 pressure screw 20 recesses 21 Piezo ring 22 Contact line 30 basic shapes 31 component 32 sensor elements 33 ceramic bodies 34 Management 210 Front 211 Electrode QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2022 133 730 A1

[0004]

Claims

[1] Vibration sensor, with a mechanically oscillating unit (1), with a converter device (2) which excites the mechanically oscillating unit (1) to mechanical vibrations and / or receives mechanical vibrations from the mechanically oscillating unit (1), and with a temperature sensor (3), characterized by , that the converter device (2) and the temperature sensor (3) form a single component. [2] Vibration sensor according to claim 1, wherein the converter device (2) has a continuous recess (20), wherein the temperature sensor (3) is essentially mushroom-shaped, in that the temperature sensor (3) has an elongated base body (30) and a support component (31) arranged at the end face and designed as a partial sphere, wherein the base body (30) is at least partially arranged in the recess (20), and wherein the support component (31) is arranged outside the recess (20). [3] Vibration sensor according to claim 2, wherein the transducer device (2) and the temperature sensor (3) are designed and coordinated such that a maximum radial extent of the support component (31) is essentially equal to a maximum radial extent of the transducer device (2). [4] Vibration sensor according to claim 1, wherein the converter device (2) has at least one lateral recess (20), wherein the temperature sensor (3) has at least one elongated base body (30) and a support component (31) arranged at the end face, wherein the base body (30) is arranged at least partially in the recess (20), and wherein the support component (31) forms an end face of the overall component consisting of the converter device (2) and the temperature sensor (3). [5] Vibration sensor according to claim 1, wherein the temperature sensor (3) has at least one elongated base body (30) and a support component (31) arranged at the end face, wherein the base body (30) at least partially encloses the transducer device (2), and wherein the support component (31) forms an end face of the overall component consisting of the converter device (2) and the temperature sensor (3). [6] Vibration sensor according to any one of claims 1 to 3, wherein the transducer device (2) comprises several piezo rings (21) arranged in a stack, and wherein the piezo rings (21) each have an electrode (211) on their end faces (210) which is led to the other end face (210). [7] Vibration sensor according to any one of claims 1 to 6, wherein the temperature sensor (3) comprises a sensor element (32) and a ceramic body (33), and wherein the sensor element (32) is arranged inside the ceramic body (33). [8] Vibration sensor according to any one of claims 1 to 7, wherein the vibration sensor has a membrane (4), wherein the mechanically oscillating unit (1) is arranged on the membrane (4), and wherein the support component (31) of the temperature sensor (3) sits on the membrane (4). [9] Vibration sensor according to any one of claims 1 to 8, wherein the mechanically oscillating unit (1) is a vibrating fork.

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