Sensor device for detecting a deformation event

Abstract

The invention relates to a sensor device (1; 51; 71), comprising a measuring body (3; 53; 73), and having a piezoelectric sensor (31; 81), which has a piezoelectrically active plastic film (32; 82), in particular made of a polyvinylidene fluoride material, equipped with at least two electrodes arranged at a distance from one another, or having at least two sensors from the following group: a piezoelectric sensor (31; 81) having a piezoelectrically active plastic film (32; 82), in particular made of a polyvinylidene fluoride material, equipped with at least two electrodes arranged spaced apart from each other; a strain sensor (23), which is designed to detect a strain of the measuring body (3; 53; 73); a position sensor (24) which is designed to detect a position of the measuring body (3; 53; 73) or the position of an actuator element (5) arranged in the measuring body.

Description

Technical Field

[0001] The invention relates to a sensor device for detecting a deformation event. Background Art

[0002] Such sensor devices can be used, for example, on components for automation technology which can be exposed to changing forces during normal use, wherein these changing forces can also manifest themselves in particular in deformation events of the respective component. Summary of the invention

[0003] The object of the present invention is to enable a cost-effective or substantially comprehensive analysis of deformation events on automation components.

[0004] This object is achieved with a sensor device of the type mentioned at the outset in that the sensor device comprises a measuring body having a surface which can be elastically deformed due to external forces acting on the measuring body and / or due to internal forces acting on the measuring body, and also a piezoelectric sensor having a piezoelectrically active plastic film, in particular made of a polyvinylidene fluoride material, wherein the piezoelectrically active plastic film is provided with at least two electrodes arranged at a distance from one another, in particular for measuring a voltage across the plastic film or for measuring a current across the plastic film, or in addition to the measuring body, the sensor device has at least two sensors from the following group: a piezoelectric sensor having a piezoelectrically active plastic film made of a polyvinylidene fluoride material, wherein the piezoelectrically active plastic film is provided with at least two electrodes arranged at a distance from one another, in particular for measuring a voltage across the plastic film or for measuring a current across the plastic film; a strain sensor designed as a strain gauge for detecting a deformation of the measuring body; a position sensor designed for detecting a position of an actuator element arranged movably on or in the measuring body.

[0005] The measuring body is the component whose state is to be monitored by means of the assigned sensor. In a first embodiment, the measuring body is assigned a piezoelectric sensor having a piezoelectrically active plastic film, in particular made of a polyvinylidene fluoride material, wherein the piezoelectrically active plastic film is provided with at least two electrodes arranged at a distance from each other, which electrodes enable the measurement of the charge transfer that may take place in the piezoelectric plastic film during a strain change, in particular the tapping of the voltage of the plastic film or the measurement of the current on the plastic film. By means of such a piezoelectric sensor, which is preferably adapted to the measuring body or can be connected to the measuring body materially, a charge change is provided depending on the deformation of the measuring body and / or depending on the vibration of the measuring body, which charge change can be converted into a state signal of the measuring body by a suitable evaluation device. In another embodiment, a combination of sensors is provided, which includes a piezoelectric sensor, a strain sensor and a position sensor, wherein at least two sensors from the aforementioned group are arranged on the measuring body. The strain sensor can be used in the same way as the piezoelectric sensor to determine the elastic deformation or elastic and plastic deformation of the measuring body. Position sensors are of interest if an actuator element is movably arranged on or in the measuring body, the relative position of which is to be determined. By combining the sensor signals from the sensors of the aforementioned group, useful information about the state of the measuring body can be determined, in particular in the manner of an observer, i.e. a virtual sensor.

[0006] Advantageous embodiments of the invention are the subject matter of the dependent claims.

[0007] Advantageously, the piezoelectric sensor and / or the strain sensor is accommodated between a measuring body and a pressure body coupled to the measuring body, wherein the pressure body has a pressure surface which is geometrically designed similarly to the surface of the measuring body provided with the piezoelectric sensor and / or the strain sensor, so that the piezoelectric sensor and / or the strain sensor bears against the surface of the measuring body in a force-fitting manner, in particular only in a force-fitting manner. The pressure body is used to couple the piezoelectric sensor and / or the strain sensor to the measuring body, so that on the one hand it is ensured that the deformation of the measuring body is transmitted to the piezoelectric sensor and / or the strain sensor, and on the other hand it is not necessary to establish a material-fitting connection between the measuring body and the piezoelectric sensor and / or the strain sensor, which is advantageous in particular when these sensors are mounted on the measuring body. The pressure body is preferably made of a material with high elasticity, for example a rubber-elastic material, in order to ensure that the force is applied to the sensor in a favorable and uniform manner.

[0008] In one embodiment of the invention, it is provided that the position sensor is designed as a pressure body. In this embodiment variant, the position sensor, which is usually accommodated in a dimensionally stable housing, can exert pressure on other sensors. Preferably, an elastic intermediate layer is arranged between the position sensor and the piezoelectric sensor and / or the strain sensor.

[0009] In another embodiment of the invention, it is provided that the measuring body is designed as an actuator housing of an actuator, wherein the actuator housing defines a working chamber in which a working element is accommodated in a movable manner along a movement path between a first functional position and a second functional position, the working element dividing the working chamber into a first working space of variable size and a second working space of variable size, wherein the first working space is assigned a fluid connection end, which is designed for ventilation and exhaust of the first working space. Such an actuator can be designed in particular as a single-acting or double-acting cylinder or as a pneumatic rotary drive. For such an actuator, the goal to be achieved with the sensor device can be, for example, to obtain a state image that is as complete as possible, independently of the pneumatic supply system, from which signs of wear such as wear of the cylinder liner or the sealing element can also be seen.

[0010] Advantageously, the measuring body is designed as a clamping finger of a gripper and is accommodated in a movably manner on a gripper housing of the gripper. In this embodiment variant, in particular, the clamping force exerted by the clamping finger on the object to be gripped can be determined.

[0011] Alternatively, it is provided that the measuring body is designed as a housing of a fluid-conducting component. In this embodiment variant, in particular, an operating state of a fluid-conducting component can be indicated, which can be a fitting or a pneumatic control valve, in particular a switching valve or a proportional valve, purely by way of example. In this case, for example, structure-borne noise events caused by a fluid flow in the fluid-conducting component are evaluated, which structure-borne noise events can preferably be determined using piezoelectric sensors. If necessary, the setting of the fluid-conducting component (closed, partially open, completely open) and / or the wear state of the fluid-conducting component can be determined therefrom.

[0012] Preferably, it is provided that the piezoelectric sensor is electrically connected to an evaluation device, in particular via a two-wire connection, which is designed to detect the time-varying charge of the plastic film. The evaluation device has the task of processing, in particular amplifying, the signal of the piezoelectric sensor and generating information therefrom which can be provided, for example, to a higher-level controller.

[0013] In an advantageous embodiment of the invention, it is provided that the evaluation device comprises a transimpedance amplifier, in particular a transimpedance amplifier designed as a low-noise operational amplifier, and is designed to evaluate the signal of the piezoelectric sensor with respect to structure-borne noise events and / or deformation events.

[0014] It is expedient if the plastic film of the piezoelectric sensor is locally provided with a conductor track, in particular a conductor track designed in a meandering shape, which is electrically connected to the evaluation device, wherein the evaluation device is designed to determine the temperature of the piezoelectric sensor. This allows a temperature determination to be performed directly on the piezoelectric sensor, with which a temperature compensation of the sensor signal of the piezoelectric sensor can be performed in order to increase the measuring accuracy of the piezoelectric sensor.

[0015] In a further embodiment of the invention, it is provided that the strain sensor is electrically connected to the evaluation device, in particular via a four-wire connection, and that the evaluation device is designed to evaluate the signal of the strain sensor in relation to the deformation event.

[0016] It is preferably provided that the evaluation device is designed for combined evaluation of the signals of the piezoelectric sensor and / or the strain sensor and the signals of the position sensor. The signals of the piezoelectric sensor and / or the strain sensor can advantageously be interpreted if the position of an actuator element which is movably accommodated on or in the measuring body and whose relative position can depend, for example, on the operating pressure in the measuring body is known.

[0017] Advantageously, the evaluation device is designed to determine a structure-borne noise event based on the sensor signal of the piezoelectric sensor and to determine a pressure change event based on the sensor signal of the strain sensor. This makes it possible, for example, when the measuring body is designed as an actuator housing of an actuator, to indicate whether an actuator member of the actuator encounters an obstacle (e.g. a component to be pressed into a workpiece) during the relative movement relative to the actuator housing caused by the pressure change event, since in this case a structure-borne noise event occurs, which can be determined by means of the piezoelectric sensor.

[0018] In an advantageous extension of the invention, it is provided that an insulating film is arranged between the actuator housing and the piezoelectric sensor and / or between the actuator housing and the strain sensor, the insulating film being designed to be conductive on one side, in particular being designed as a copper-clad polyimide film (Kapton film), wherein the conductive surface of the insulating film faces the piezoelectric sensor and / or the strain sensor. The insulating film ensures the electrical insulation of the piezoelectric sensor and / or the strain sensor relative to the measuring body, which is usually made of a metallic material. In addition, the piezoelectric sensor and / or the strain sensor is protected from interference radiation and, if necessary, interference emissions by the conductive surface of the insulating film. For this purpose, it can be provided that an advantageous electrical contact connection between the insulating film and the evaluation device, preferably realized on a printed circuit, is ensured by means of contact springs, which are intended to ensure that the insulating film is reliably electrically connected to the ground potential of the evaluation device.

[0019] It is expedient that the pressure body is made of a rubber-elastic material, which has conductive parts, in particular conductive parts arranged at uniform spacing, which are insulated from one another by electrically insulating parts and are designed for the electrical connection of the piezoelectric sensor and / or the strain sensor. This embodiment of the pressure body ensures a dual function, because in addition to providing contact pressure for the piezoelectric sensor and / or the strain sensor, electrical signal transmission can also be carried out via the pressure body, for example between the piezoelectric sensor and / or the strain sensor and a printed circuit placed on the pressure body.

[0020] For this purpose, it is provided in particular that the evaluation device is formed on a printed circuit board which is provided with electrical conductor tracks over the largest surface, which conductor tracks rest at least partially on electrically conductive parts of the pressure body. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] An advantageous embodiment of the invention is shown in the drawings. In this case:

[0022] Figure 1 shows a purely schematic side sectional view of a first specific embodiment of a sensor device having a measuring body designed as a cylinder and a sensor assembly having a strain sensor, a temperature sensor and a piezoelectric sensor used as a structure-borne noise sensor;

[0023] Figure 2 A purely schematic front view shows a second embodiment of a sensor device, in which clamping fingers of a clamp are used as measuring bodies and are each equipped with a piezoelectric sensor; and

[0024] Figure 3 A purely schematic front view of a third specific embodiment of a sensor device is shown, in which a fitting body of a fluid-conducting component designed as a manually actuatable regulating valve serves as a measuring body and is equipped with a piezoelectric sensor. DETAILED DESCRIPTION

[0025] exist Figure 1The sensor device 1 shown purely schematically in FIG. 1 comprises an actuator 2 designed as a double-acting cylinder and two identically designed sensor groups 21, of which one sensor group 21 is described in more detail below as a representative of the two sensor groups 21. The actuator 2 comprises an actuator housing 3 serving as a measuring body, in which a working chamber 4 is formed. A working piston 5 is accommodated in the working chamber 4 in a linearly movable manner along a displacement axis 6, which divides the working chamber 4 into a first working space 7 of variable size and a second working space 8 of variable size. Each of these working spaces 7, 8 is assigned a working connection end with a corresponding mouth opening 10, 11, which is not shown in more detail, and which allows compressed air to flow into the corresponding working space 7, 8 separately and to flow out of the corresponding working space 7, 8 separately.

[0026] Each of the two sensor groups 21 is fixed in a sensor recess 12, which is only schematically shown, of the actuator housing 3. By way of example, it is provided that the sensor group 21 comprises Figure 1 Detailed diagram of the temperature sensor 22, strain sensor 23, position sensor 24 and piezoelectric sensor 31 are shown in more detail. Here, the temperature sensor 22, strain sensor 23 and piezoelectric sensor 31 are designed to be in almost direct contact with the groove bottom 13 of the sensor groove 12, while the position sensor 24 is arranged spaced apart from the groove bottom 13.

[0027] Exemplarily, the temperature sensor 22 is a semiconductor temperature sensor with a negative temperature coefficient, also referred to as an NTC temperature sensor. The temperature sensor 22 is used to detect the temperature of the groove bottom 13. Two conductive contact fields 26 are arranged on the upper side of the temperature sensor 22, which enable the electrical signal that can be provided by the temperature sensor 22 to be scanned.

[0028] The strain sensor 23 is designed purely by way of example as a strain gauge and provides an electrical signal at the contact field 27 which is dependent on the strain of the strain sensor 23. The strain sensor 23 is thereby able to detect a strain change in the region of the groove bottom 13, wherein the strain change is caused in particular by a pressure increase or a pressure decrease in the respective working space 7 or 8. From the electrical signal of the strain sensor 23, it is therefore possible to infer the pressure prevailing in the respective working space 7 or 8. It is preferably provided that the strain sensor 23 is arranged in the groove bottom 13 such that it detects a strain transversely to the main extension direction of the sensor groove 12. By such an orientation of the strain sensor 23, a pressure-dependent strain of the actuator housing 3 is advantageously detected, without any force feedback to the actuator housing 3 which may occur due to a reaction force on the working piston 5 at least largely influencing the strain sensor 23, so that a fairly accurate pressure detection of the pressure prevailing in the actuator housing 3 is ensured.

[0029] The piezoelectric sensor 31 comprises a piezoelectrically active plastic film 32 which is made purely by way of example from a polyvinylidene fluoride material and which is provided with a metal coating on both sides, whereby an upper electrode 33 and a lower electrode 34 can be formed. By way of example, it is provided that, starting from the lower electrode, a plated through hole extends through the plastic film 32 as far as the upper side of the plastic film and forms a contact field 36 there. In order to prevent an electrically conductive connection between the upper electrode 33 and the contact field 36, the metal coating on the upper side of the plastic film 32 is interrupted in places.

[0030] For the advantageous electrical contacting of the contact fields 26 of the temperature sensor 22, the contact fields 27 of the strain sensor 23, and the upper electrode 33 and the contact fields 36 of the piezoelectric sensor 31, a pressure body 25 is provided, which is designed as a so-called zebra element or conductive rubber, and which is implemented as a regular layer structure consisting of insulating layers and conductive layers. Purely by way of example, it can be provided that these insulating layers and these conductive layers are respectively made of silicone material, wherein these conductive layers can be implemented, for example, with fillers made of conductive carbon material or with conductive wires. The spacing of the conductive layers separated by the electrical insulating layers is selected so that each of the contact fields 26, 27, 36 and the upper electrode 33 can be reliably contacted and ensure electrical connection with the electrical conductor tracks 42 of the circuit board 41 designed as a printed circuit.

[0031] As from Figure 1As can be seen from the detailed diagram of , it is provided that each of the contact fields 26 of the temperature sensor 22 and each of the contact fields 27 of the strain sensor 23 is connected to two mutually independent electrical printed conductor contacts, whereby the signal transmission between the temperature sensor 22 and the evaluation device 43 designed as a microprocessor and arranged on the upper side of the circuit board 41 and the strain sensor 23 and the evaluation device 43 can be realized in four-wire technology in each case, so as to ensure that interference effects on the signals of the temperature sensor 22 and the strain sensor 23 are minimized. Since the piezoelectric sensor 31 has a high resistance, the signal transmission to the evaluation device 43 can be provided in two-wire technology here.

[0032] In order to achieve an advantageous shielding of the sensor group 21 as a whole, it is provided that the sensor group 21 is covered purely by way of example with a film hose 28 provided with a copper coating 29 on the inside. The film hose 28 is produced, for example, from a polyimide film, which is mainly sold under the trade name Kapton. The printed circuit board 41 is provided with a first plug connector 44 at the end, which is designed to receive an electrical conductor arrangement (not shown) by means of which the sensor group 21 can be supplied with electricity and the output signals of the sensor group 21 can be transmitted. Instead of the film hose 28, a film arrangement with a U-shaped cross section can also be provided.

[0033] In addition to the temperature sensor 22, the strain sensor 23 and the piezoelectric sensor 31, the sensor group 21 comprises a position sensor 24, which can be designed in particular as an inductive position sensor or a Hall position sensor and which can be designed to detect the position of the working piston 5 in the corresponding end region of the actuator housing 3. By way of example, it is provided that the position sensor 24 has a sensor interface 30, via which the position sensor 24 can be supplied with power and the sensor signal of the position sensor 24 can be sampled. It is preferably provided that a microprocessor, not shown, arranged in the position sensor 24 is electrically connected to a second plug connector 45 on the printed circuit board 41 via an electrical conductor connection, likewise not shown, whereby the signal of the evaluation device 43 can be provided to the microprocessor of the position sensor 24 for further processing, so that the position sensor signal can be processed together with the signals of the temperature sensor 22, the strain sensor 23 and the piezoelectric sensor 31 there.

[0034] By way of example, it can be provided that the signal of the strain sensor 23 is used to indicate which force is exerted on the piston rod 9 of the actuator 2. Furthermore, the position of the working piston 5 of the actuator 2 can be determined using the signal of the position sensor 24. The evaluation device 43 can also be designed to evaluate the signal of the piezoelectric sensor 31 in relation to structure-borne noise events, which can occur, for example, when the piston rod 9 hits an object, as can be the case, for example, when performing a feed process or when performing a pulse introduction to an object placed loosely on a conveyor belt in order to change the direction of movement of the object. The signal of the temperature sensor 22 is used in particular to perform a temperature compensation for the signal of the piezoelectric sensor 31, the sensor signal of which is significantly temperature-dependent.

[0035] exist Figure 2 In a second embodiment of the sensor device, which is only schematically shown in FIG. 1 , clamping fingers 53 that can be moved in opposite directions are arranged on a clamp housing 54 of a parallel clamp 52. A drive device, not shown in more detail, is arranged in the clamp housing 54, which enables a relative movement of the two clamping fingers 53 in opposite directions and can be designed, for example, as an electric drive or a pneumatic drive. Each of these clamping fingers 53 is equipped with a piezoelectric sensor on an inner surface 55 that is opposite to the respective other clamping finger 53, which voltage sensor is identical to the piezoelectric sensor 31, so that a more detailed description can be omitted. Each of the piezoelectric sensors 31 is connected via an assigned sensor line 56 to an evaluation device 57, which is designed to evaluate the electrical signals of the piezoelectric sensor 31 and can, for example, determine the clamping force or determine a structure-borne noise event when the clamping finger 53 strikes an object that is not shown. In order to protect the piezoelectric sensors 31 and to ensure an advantageous force transmission between the respective clamping finger 53 and a clamped object (not shown), each of these piezoelectric sensors 31 is covered by a rubber layer 58 .

[0036] exist Figure 3In the third embodiment of the sensor device 71, the measuring body is formed by a fitting body 73 which is designed as a manually operable regulating valve and is referred to as a fluid conducting component of the fitting 72. A piezoelectric sensor 81 is mounted on a purely exemplary flat front side 74 of the fitting body 73, for example, is glued to the front side. Exemplarily, the piezoelectric sensor 81 comprises a rectangularly cut piezoelectrically active plastic film 82, which is locally provided with a metallization designed in the form of a strip on the front side facing the observer and on the rear side facing the fitting body 73, thereby forming an upper electrode 83 and a lower electrode 84 which is only shown in dashed lines. The lower electrode 84 is connected to a contact field 86 on the front side of the piezoelectric sensor 81 via a plated through hole, which is not shown in more detail, so that the two electrodes 83, 84 can be electrically contacted from the front side of the piezoelectric sensor 81. Furthermore, on the front side, a resistance line designed in a meandering shape and which can be used as a temperature sensor 87 is also applied as a metal coating to the piezoelectrically active plastic film 82, which has a contact field in each of the opposite end regions. The temperature sensor 87 changes its resistance as a function of the temperature of the piezoelectrically active plastic film 82 and can thus be used by the evaluation device 75 for temperature compensation of the signals of the two electrode arrangements 83, 84. By way of example, it can be provided that the evaluation device 75 is designed to detect structure-borne noise events on the fitting 72, for example when a fluid such as compressed air or water flows through the fitting 72 (this is done by Figure 3 These structure-borne noise events may occur when the adjustment of the accessory 72 is performed on the hand wheel 76 (indicated by two side arrows in FIG. 7 ) or when the adjustment of the accessory 72 is performed on the hand wheel 76.

Claims

1. A sensor device (1; 51; 71) for detecting a deformation event, The sensor device comprises a measuring body (3; 53; 73), which has a surface which can be elastically deformed due to an external force acting on the measuring body (3; 53; 73) and / or due to an internal force acting on the measuring body, and the sensor device comprises a piezoelectric sensor (31; 81), which has a piezoelectrically active plastic film (32; 82), in particular made of polyvinylidene fluoride material, wherein The piezoelectrically active plastic film (32; 82) is provided with at least two electrodes spaced apart from each other, in particular for measuring a voltage across the piezoelectrically active plastic film (32; 82) or for measuring a current across the plastic film (32; 82), or the sensor device comprises at least two sensors from the following group: a piezoelectric sensor (31; 81) having a piezoelectrically active plastic film (32; 82), in particular made of polyvinylidene fluoride material, wherein the piezoelectrically active plastic film (32; 82) is provided with at least two electrodes spaced apart from each other Electrodes (33, 34; 83, 84) arranged in a spaced-apart manner, in particular for measuring the voltage of the piezoelectrically active plastic film (32; 82) or for measuring the current on the plastic film (32; 82); a strain sensor (23), which is designed as a strain gauge for detecting the deformation of the measuring body (3; 53; 73); a position sensor (24), which is designed for detecting the position of an actuator element (5) arranged in a movably manner on or in the measuring body (3; 53; 73).

2. The sensor device (1; 51; 71) according to claim 1, characterized in that The piezoelectric sensor (31; 81) and / or the strain sensor (23) are accommodated between the measuring body (3; 53; 73) and a pressure body (25) coupled to the measuring body (3; 53; 73), wherein the pressure body (25) has a pressure surface which is geometrically designed to be similar to a surface of the measuring body (3; 53; 73) equipped with the piezoelectric sensor (31; 81) and / or the strain sensor (23), so that the piezoelectric sensor (31; 81) and / or the strain sensor (23) rests on the surface of the measuring body (3; 53; 73) in a force-fitting manner, in particular only in a force-fitting manner.

3. The sensor device (1; 51; 71) according to claim 2, characterized in that The position sensor (24) is designed as a pressure body.

4. The sensor device (1; 51; 71) according to claim 1, 2 or 3, characterized in that The measuring body (3; 53; 73) is designed as an actuator housing (3) of an actuator (2), wherein the actuator housing (3) defines a working room (4) in which a working element (5) is accommodated in a manner movable along a moving path (6) between a first functional position and a second functional position, wherein the working element (5) divides the working room (4) into a first working space (7) of variable size and a second working space (8) of variable size, wherein the first working space (7) is assigned a fluid connection end, which is designed for ventilation and exhaust of the first working space (7).

5. The sensor device (1; 51; 71) according to claim 1, 2 or 3, characterized in that The measuring body (3; 53; 73) is designed as a clamping finger (53) of a clamp (52) and is accommodated movably on a clamp housing (54) of the clamp (52).

6. The sensor device (1; 51; 71) according to claim 1, 2 or 3, characterized in that The measuring body (3; 53; 73) is designed as a housing of a fluid-conducting fitting (72).

7. The sensor device (1; 51; 71) according to any one of the preceding claims, characterized in that The piezoelectric sensor (31; 81) is electrically connected to an evaluation device (43; 57; 75), in particular via a two-wire connection, which is designed to detect a time-varying charge of the piezoelectrically active plastic film (32; 82).

8. The sensor device (1; 51; 71) according to claim 7, characterized in that The evaluation device (43; 57; 75) comprises a transimpedance amplifier, in particular a transimpedance amplifier designed as an operational amplifier, and is designed to evaluate the signal of the piezoelectric sensor (31; 81) in relation to structure-borne noise events and / or deformation events.

9. The sensor device (1; 51; 71) according to claim 7 or 8, characterized in that The piezoelectrically active plastic film (32; 82) of the piezoelectric sensor (31; 81) is locally equipped with a printed conductor (87), in particular a printed conductor designed in a meandering shape, which is electrically connected to the evaluation device (43; 57; 75), wherein the evaluation device (43; 57; 75) is designed to determine the temperature of the piezoelectric sensor (31; 81).

10. The sensor device (1; 51; 71) according to any one of the preceding claims, characterized in that The strain sensor (23) is electrically connected to an evaluation device (43; 57; 75), in particular via a four-wire connection; and the evaluation device (43; 57; 75) is designed to evaluate a signal of the strain sensor (23) in relation to a deformation event.

11. The sensor device (1; 51; 71) according to any one of claims 7 to 10, characterized in that The evaluation device (43; 57; 75) is designed to carry out a combined evaluation of the signals of the piezoelectric sensor (31; 81) and / or the strain sensor (23) and the signal of the position sensor (24).

12. The sensor device (1; 51; 71) according to any one of claims 7 to 11, characterized in that The evaluation device (43; 57; 75) is designed to determine a structure-borne noise event based on the sensor signal of the piezoelectric sensor (31; 81) and to determine a pressure change event based on the sensor signal of the strain sensor (23).

13. The sensor device (1; 51; 71) according to any one of the preceding claims, characterized in that An insulating film (28) is arranged between the actuator housing (3) and the piezoelectric sensor (31; 81) and / or between the actuator housing (3) and the strain sensor (23), wherein the insulating film is designed to be conductive on one side, in particular, is designed to be a copper-clad polyimide film, wherein the conductive surface of the insulating film (28) faces the piezoelectric sensor (31; 81) and / or the strain sensor (23).

14. The sensor device (1; 51; 71) according to any of the preceding claims in combination with claim 2, characterized in that The pressure body (25) is made of a rubber elastic material, which has a conductive part, especially a conductive part arranged at a uniform interval, the conductive parts are insulated from each other by an electrically insulating part, and the conductive part is designed for electrical connection of the piezoelectric sensor (31; 81) and / or the strain sensor (23).

15. The sensor device (1; 51; 71) according to claim 14, characterized in that The evaluation device (43; 57; 75) is formed on a printed circuit board (41), which is provided with electrical conductor tracks (42) on the largest surface, which are at least partially placed on electrically conductive parts of the pressure body (25).

Images