JP2015004667A - Sensor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor device capable of determining whether an introduction hole is blocked.SOLUTION: A sensor device has: a pressure sensor 10; a processing unit 20; a housing 30 having formed therein an introduction hole 31 for guiding a fluid to be measured to the pressure sensor 10; and a vibration unit for generating, inside the introduction hole 31, a steady wave having a resonance frequency determined by the shape and state of the introduction hole by vibrating the fluid to be measured in the introduction hole 31. The introduction hole 31, open at one end and closed at other end, is provided in the housing 30 so that the pressure sensor 10 can detect, at the closed other end, the pressure of the fluid to be measured in the introduction hole 31. When the steady wave is generated inside the introduction hole 31 by the vibration unit 40, the pressure sensor 10 outputs an electric signal corresponding to the resonance frequency and cyclically changing in amplitude. The processing unit 20 determines, on the basis of the frequency of the electric signal corresponding to the resonance frequency and outputted by the pressure sensor 10, whether the introduction hole 31 is blocked by foreign matter.

Description

  The present invention is a sensor device comprising: a pressure sensor; a processing unit that processes an electrical signal of the pressure sensor; and a housing that houses the pressure sensor and the processing unit and that has an introduction hole that guides a fluid to be measured to the pressure sensor. It is about.

  Conventionally, for example, as disclosed in Patent Document 1, a pressure sensor in which a sensor element for pressure detection is housed in a sensor body, a chamber member in which a chamber space is formed and disposed in a vehicle bumper, , A vehicle collision detection device has been proposed. This vehicle collision detection device detects a pressure in a chamber space by a sensor element, and detects a collision with a vehicle bumper based on the pressure detection result. The chamber member is provided with an opening for communicating the chamber space to the outside and an opening for fixing the sensor body. The sensor body is provided with a pressure inlet for introducing pressure in the chamber space.

JP 2010-69978 A

  As described above, in the vehicle collision detection device disclosed in Patent Document 1, the sensor body is fixed to one of the two openings of the chamber member. Therefore, when the other opening of the chamber member (introduction hole) is blocked by a foreign substance (for example, ice), a desired pressure cannot be detected.

  In view of the above problems, an object of the present invention is to provide a sensor device that can determine whether or not an introduction hole is blocked.

  In order to achieve the above object, the present invention provides a pressure sensor (10) for converting the pressure of a fluid to be measured into an electrical signal, a processing unit (20) for processing the electrical signal of the pressure sensor, a pressure sensor, and a processing. Is determined by the shape and state of the introduction hole by vibrating the fluid to be measured in the introduction hole and the housing (30) in which the introduction hole (31) for guiding the measurement fluid to the pressure sensor is formed. And a vibration part (40, 204) for generating a standing wave having a resonance frequency in the introduction hole. The introduction hole has one end opened, the other end closed, and a pressure sensor at the other closed end. Is provided in the housing so that the pressure of the fluid to be measured in the introduction hole can be detected, and the pressure sensor periodically amplitudes according to the resonance frequency when a standing wave is generated in the introduction hole by the vibration unit. Electric signal with variable Output, processing unit, based on the frequency of the electrical signal of the pressure sensor corresponding to the resonant frequency, and judging whether it is closed introducing hole by foreign substances.

  When one end of the introduction hole (31) is opened and the other end is closed (hereinafter referred to as an open state for the sake of convenience), a standing wave with the one end side of the introduction hole (31) as an abdomen and the other end side as a node is introduced into the introduction hole. (31). In contrast, when one end of the introduction hole (31) is closed by a foreign substance and the introduction hole (31) is closed (hereinafter, referred to as a closed state for convenience), one end side and the other end of the introduction hole (31) Standing waves having nodes on each side are generated in the introduction hole (31). Since the frequencies (resonance frequencies) of the two standing waves are different from each other, the frequency of the electric signal output from the pressure sensor (10) is also different. Therefore, in the present invention, based on the frequency of the electrical signal of the pressure sensor (10), it is determined whether or not the introduction hole (31) is blocked by foreign matter. Thereby, when the introduction hole (31) is obstruct | occluded with the foreign material, it is recognized that the electrical signal output from a pressure sensor (10) differs from a desired physical quantity.

  The processing unit has a threshold value based on the frequency of the electrical signal output from the pressure sensor when the introduction hole is not completely blocked by the foreign matter, and the processing unit has a frequency of the electrical signal output from the pressure sensor. Based on the magnitude relationship with the threshold value, it may be determined whether or not the introduction hole is blocked by a foreign substance.

  When a part of the introduction hole (31) is blocked by a foreign substance, the frequency of the standing wave formed in the introduction hole (31) (hereinafter referred to as resonance frequency) may be different from the resonance frequency of the standing wave in the open state. Is expensive. Therefore, for example, when determining whether or not the introduction hole (31) is closed based on the frequency of the electrical signal of the pressure sensor (10) in the open state, a part of the introduction hole (31) is closed. There is a possibility that it is determined to be in a closed state even though it has only been performed. Therefore, as described above, the threshold value is determined based on the electrical signal output from the pressure sensor (10) when the introduction hole (31) is not completely closed. By doing so, it is possible to suppress erroneous determination of the closed state of the introduction hole (31) as compared with the above-described comparative configuration.

  The vibration part can be provided in the introduction hole. According to this, even if a foreign substance adheres in the introduction hole (31), the foreign substance can be removed by the vibration of the vibration part (40).

  Furthermore, the threshold value is higher than the frequency of the electrical signal output from the pressure sensor when the introduction hole is open, and is lower than the frequency of the electrical signal output from the pressure sensor when the introduction hole is blocked by foreign matter. If the processing unit determines that the frequency of the electrical signal output from the pressure sensor is lower than the threshold value, the processing unit determines that the introduction hole is not blocked by a foreign object, and the electrical signal output from the pressure sensor. If it is determined that the frequency is equal to or higher than the threshold value, the introduction hole may be determined to be blocked by foreign matter.

  When the vibration part (40) is provided in the introduction hole (31), whether the introduction hole (31) is closed or not, the object to be measured in the introduction hole (31) by the vibration part (40). The fluid is vibrated and a standing wave is generated in the introduction hole (31). However, as described above, the resonance frequency of the standing wave generated in the introduction hole (31) varies depending on whether or not the introduction hole (31) is closed. The resonance frequency in the closed state is higher than the resonance frequency in the open state, which is approximately twice. Therefore, the threshold is set higher than the frequency of the electrical signal output from the pressure sensor (10) in the open state and lower than the frequency of the electrical signal output from the pressure sensor (10) in the closed state. When the processing unit (20) determines that the frequency of the electrical signal output from the pressure sensor (10) is lower than the threshold, the processing unit (20) determines that the introduction hole (31) is in the open state, and the pressure sensor (10). When it is determined that the frequency of the electric signal output from the input signal is equal to or higher than the threshold value, the introduction hole (31) is determined to be in a closed state.

  The vibration part may be provided on one end side of the inner wall of the introduction hole. According to this, unlike the configuration in which the vibration part (40) is provided on the other end side of the inner wall of the introduction hole (31), the vibration having a specific frequency generated in the vibration part (40) is detected by the pressure sensor. Transmission to (10) is suppressed. Therefore, it is suppressed that the precision which determines whether the introduction hole (31) is obstruct | occluded with the foreign material is reduced.

  The vibration part may be provided not only on one end side of the inner wall of the introduction hole but on the entire surface. According to this, as compared with the configuration in which the vibrating portion (40) is provided on a part of the inner wall of the introduction hole (31), the foreign matter attached in the introduction hole (31) is removed regardless of the attachment location. can do.

It is a fragmentary sectional view which shows the attachment state to the inner panel of a sensor apparatus. It is the fragmentary sectional view which expanded the site | part enclosed with the broken line of FIG. It is a top view which shows the sensor apparatus seen from the direction of the white arrow shown in FIG. It is sectional drawing which follows the IV-IV line | wire shown in FIG. It is a model figure which shows the standing wave in the state which one end of the pipe | tube was opened and the other end was closed. It is a model figure which shows the standing wave in the state in which the both ends of the pipe | tube were closed. It is sectional drawing which shows the modification of a sensor apparatus. It is sectional drawing which shows the specific shape of a pressure sensor and a vibration part. It is a fragmentary sectional view showing a modification of a vibration part.

Hereinafter, an embodiment in which a sensor device according to the present invention is provided at a door of a vehicle and used for driving control of a side impact airbag will be described with reference to the drawings.
(First embodiment)
The sensor device according to the present embodiment will be described with reference to FIGS. In FIG. 3, the cross-sectional shape of the introduction hole 31 is represented by a broken line, and the inner panel 200 is omitted in FIGS. 3 and 4. In FIG. 4, the control circuit 203 mounted on the vehicle is schematically shown as a block, and the electrical connection between the control circuit 203 and the sensor device 100 is indicated by a broken line.

  In the following, the three directions that are orthogonal to each other are referred to as an x direction, a y direction, and a z direction. A plane defined by the x direction and the y direction is an xy plane, a plane defined by the y direction and the z direction is a yz plane, and a plane defined by the z direction and the x direction is z−. Shown as x-plane.

  As shown in FIG. 1, the sensor device 100 according to this embodiment is provided on an inner panel 200 inside the door. As shown in FIG. 4, the sensor device 100 includes a pressure sensor 10, a processing unit 20, a housing 30, and a vibration unit 40. The pressure sensor 10 converts the pressure of the fluid to be measured into an electrical signal. An electrical signal output from the pressure sensor 10 is output to the processing unit 20. Although described in detail later, the processing unit 20 performs processing such as foreign object detection processing based on the received electrical signal. The housing 30 houses the pressure sensor 10 and the processing unit 20. The housing 30 is formed with an introduction hole 31 that guides the fluid to be measured to the pressure sensor 10. The vibration part 40 vibrates the fluid to be measured in the introduction hole 31 and generates a standing wave having a resonance frequency determined by the shape and state (open state or closed state described later) of the introduction hole 31. When a standing wave is applied to the pressure sensor 10, an electrical signal whose amplitude periodically varies according to the resonance frequency is output from the pressure sensor 10. The fluid to be measured according to this embodiment is air.

  As shown in FIG. 4, the introduction hole 31 is normally in a state where one end is opened and the other end is closed (hereinafter referred to as an open state for convenience). However, when one end of the introduction hole 31 is closed by a foreign matter such as water sprayed on the vehicle or ice formed by freezing water in the atmosphere, the introduction hole 31 is closed (hereinafter referred to as a closed state for convenience). Show). When the state of the introduction hole 31 changes in this way, the resonance frequency of the standing wave generated by the vibration unit 40 also changes. As a result, the pressure applied to the pressure sensor 10 also varies, and the frequency of the electrical signal output from the pressure sensor 10 also changes. The processing unit 20 determines whether one end of the introduction hole 31 is closed based on the frequency of the electrical signal of the pressure sensor 10. In other words, the processing unit 20 determines whether the introduction hole 31 is in an open state or a closed state based on the frequency of the electrical signal of the pressure sensor 10. Hereinafter, each of the components 10 to 40 of the sensor device 100 will be described in detail.

  The pressure sensor 10 normally outputs an electric signal corresponding to a pressure fluctuation in a space (hereinafter, referred to as a detected space 202) formed between the inner panel 200 and the outer panel 201 of the vehicle due to an external force applied to the vehicle. It performs the function to output. This electrical signal is output to a control circuit 203 that controls the airbag system of the vehicle. The control circuit 203 controls the driving of the airbag based on the electric signal from the pressure sensor 10. Needless to say, as described above, the pressure sensor 10 also functions to output an electrical signal corresponding to the resonance frequency of the standing wave to the processing unit 20 when the introduction hole 31 is inspected.

  As shown in FIG. 4, the pressure sensor 10 is provided on one surface 11 a of the wiring board 11. In addition to the pressure sensor 10, a processing unit 20 is provided on the one surface 11a, and a capacitor 12 is provided on the back surface 11b. Each of the pressure sensor 10, the processing unit 20, and the capacitor 12 is electrically connected via the wires 13 and the wiring of the wiring board 11 to form a circuit.

  The processing unit 20 has a threshold value based on the frequency of the electrical signal output from the pressure sensor 10 when one end of the introduction hole 31 is not completely closed by the foreign matter. Based on the magnitude relationship between the frequency and the threshold value, it is determined whether one end of the introduction hole 31 is closed by a foreign object. As will be described later, the vibrating portion 40 is provided in the introduction hole 31. Therefore, regardless of whether one end of the introduction hole 31 is closed, the fluid to be measured in the introduction hole 31 is vibrated by the vibration unit 40, and a standing wave is generated in the introduction hole 31. However, the resonance frequency of the standing wave generated in the introduction hole 31 varies depending on whether or not the introduction hole 31 is closed.

  As shown in FIG. 5, in a state where one end of the tube is opened and the other end is closed (opened state), a standing wave having one end as an antinode and the other end as a node is generated in the tube. In contrast, as shown in FIG. 6, in a state where both ends of the tube are closed (closed state), a standing wave having nodes at one end and the other end is generated in the tube. Thus, the standing wave generated in the tube is different between the open state and the closed state, and the resonance frequency is also different. In the closed state, the resonance frequency is higher than that in the open state, which is about twice as high. Therefore, the threshold is set higher than the frequency of the electrical signal output from the pressure sensor 10 in the open state and lower than the frequency of the electrical signal output from the pressure sensor 10 in the closed state. When the processing unit 20 determines that the frequency of the electrical signal output from the pressure sensor 10 is lower than the threshold, the processing unit 20 determines that the introduction hole 31 is in an open state, and the frequency of the electrical signal output from the pressure sensor 10 is When it determines with it being more than a threshold value, it determines with the introduction hole 31 being a obstruction | occlusion state.

  When a part, not all, of one end of the introduction hole 31 is closed by a foreign substance (when the opening area of one end is reduced), the resonance frequency of the standing wave formed in the introduction hole 31 is the steady wave in the open state. The resonance frequency may be slightly different. Specifically, the resonance frequency of the standing wave may approach the resonance frequency of the closed state from the resonance frequency of the open state. Considering this, as described above, the threshold value is set higher by a predetermined value than the frequency of the electric signal output from the pressure sensor 10 when one end of the introduction hole 31 is not closed at all by the foreign matter. Yes. This predetermined value is determined by whether or not the degree of blocking of the introduction hole 31 by a foreign substance affects the detection accuracy of the pressure of the fluid to be detected. That is, when the detected resonance frequency is higher than the resonance frequency in the open state and lower than the threshold value, the detection accuracy of the pressure of the fluid to be detected does not decrease so much, and the pressure of the fluid to be detected can be detected. It is considered to be in an open state. On the other hand, if the detected resonance frequency is higher than the threshold value and lower than the resonance frequency in the closed state, the detection accuracy of the pressure of the detected fluid is significantly lowered, and the pressure of the detected fluid cannot be detected. Is considered to be in a blocked state.

  Although not shown, the processing unit 20 according to the present embodiment includes a filter that extracts a frequency in a specific band, a measurement unit that measures the frequency of an electric signal of the pressure sensor 10 via the filter, and a frequency that is measured by the measurement unit. A comparison unit that compares the reference frequency corresponding to the threshold value. At this time, for example, if a Hi signal is output from the comparison unit, it is determined that one end of the introduction hole 31 is closed by a foreign object, and if a Lo signal is output from the comparison unit, it is determined that one end of the introduction hole 31 is not closed by a foreign object. Is done.

  The housing 30 is attached and fixed to the inner panel 200 while housing the pressure sensor 10 and the processing unit 20. A plurality of terminals 32 are insert-molded in the housing 30, and some of the terminals 32 are electrically connected to a circuit formed on the wiring board 11 via the wires 14 and are electrically connected to the vibration unit 40. The remaining terminals 32 are electrically connected to the wiring board 11 via the wires 15.

  The housing 30 communicates the storage portion 33 having a storage space for storing the wiring substrate 11, the support portion 34 for supporting the wiring substrate 11 stored in the storage space, and the storage space and the detected space 202. And an introduction part 35 in which an introduction hole 31 for introducing a fluid to be measured to the pressure sensor 10 is formed. The support portion 34 has an annular shape, and one of two open ends formed by the support portion 34 communicates with the introduction hole 31. As shown in FIG. 4, one end of the support portion 34 is fixed to the storage portion 33 so as to surround the other end of the introduction hole 31, and the other end is in contact with the one surface 11 a of the wiring board 11. Thereby, the other end of the introduction hole 31 is closed by the support portion 34 and the wiring board 11, and a space communicating with the introduction hole 31 is formed by a part of the one surface 11 a and the inner ring surface of the support portion 34. Yes. The pressure sensor 10 and the processing unit 20 are positioned in this space, and the pressure of the fluid to be measured in the introduction hole 31 is applied to the pressure sensor 10 at the other end of the closed introduction hole 31. A part of the space where the pressure sensor 10 and the processing unit 20 are located is filled with a gel-like protection member 36 that protects the pressure sensor 10 and the processing unit 20. Therefore, when the vibration unit 40 is in a non-driven state, the pressure of the fluid to be measured in the detection space 202 is transmitted to the pressure sensor 10 through the introduction hole 31 and the protection member 36. On the other hand, when the vibration unit 40 is in a driving state, a stationary wave is transmitted to the pressure sensor 10 along with the pressure of the fluid to be measured in the detection space 202 through the introduction hole 31 and the protection member 36. The pressure of the fluid to be measured in the detection space 202 usually corresponds to atmospheric pressure. Therefore, when the vibration unit 40 is in a driving state, only a standing wave is substantially transmitted to the pressure sensor 10.

  As shown in FIGS. 2 and 3, the housing 30 includes a blade portion 37 connected to the storage portion 33 in addition to the above-described components 31 to 36. Two blade portions 37 are formed in the storage portion 33, and the two blade portions 37 are arranged in the y direction via the storage portion 33. The facing surface 37a of the blade portion 37 facing the inner panel 200 and the facing surface 33a of the storage portion 33 facing the inner panel 200 are flush with each other, and the facing distance between the facing surfaces 33a, 37a and the inner panel 200 is constant. ing. By providing the sealing member 38 having elasticity between the facing surfaces 33a and 37a and the inner panel 200, communication between the detected space 202 and the external space is suppressed. As shown in FIG. 3, the sealing member 38 has a circular planar shape in the yz plane, and the length (thickness) in the x direction is constant.

  Although not shown, each of the two blade portions 37 is formed with a first through hole, and the inner panel 200 is formed with a second through hole corresponding to the first through hole. Each of the two through holes is arranged in the x direction, and an insertion portion 39 made of a screw, a bolt, a rivet or the like is inserted into each of the two through holes. In addition, in the first through hole formed in the blade portion 37, in order to withstand insertion of the insertion portion 39, a material that is higher in rigidity than the resin material constituting the housing 30 (for example, the same metal material as the insertion portion 39). ) Is provided. The insertion portion 39 is in direct contact with this collar.

  The vibrating unit 40 generates a standing wave in the introducing hole 31 by vibrating the fluid to be measured in the introducing hole 31 and applies a pressure generated by the standing wave to the pressure sensor 10. As shown in FIG. 4, in this embodiment, the vibrating part 40 is provided in the introduction hole 31. Specifically, the vibration part 40 is provided on all the inner walls of the introduction hole 31. Thereby, the vibration part 40 has the same shape as the inner wall of the introduction hole 31 and is tubular. When an electric signal is input to the vibration unit 40, the vibration unit 40 vibrates according to the frequency of the electric signal. Therefore, sound is generated from the vibration part 40 and a standing wave is generated in the introduction hole 31.

  Next, functions and effects of the sensor device 100 according to the present embodiment will be described. As described above, when the introduction hole 31 is in the open state and in the closed state, the standing wave generated in the introduction hole 31 is different and the resonance frequency is also different. The frequency of the signal is also different. For this reason, the processing unit 20 can determine whether or not the introduction hole 31 is blocked by a foreign substance based on the frequency of the electrical signal of the pressure sensor 10. Thereby, when the introduction hole 31 is obstruct | occluded with the foreign material, it is recognized that the electrical signal output from the pressure sensor 10 differs from a desired physical quantity.

  The processing unit 20 has a threshold value based on the frequency of the electrical signal output from the pressure sensor 10 when the introduction hole 31 is not completely blocked by foreign matter, and this threshold value is completely blocked by the foreign matter. The frequency is set higher than the frequency of the electrical signal output from the pressure sensor 10 when not.

  When a part of the introduction hole 31 is blocked by a foreign substance, the frequency (resonance frequency) of the standing wave generated in the introduction hole 31 is likely to be different from the resonance frequency of the standing wave in the open state. Therefore, for example, when determining whether or not the introduction hole 31 is closed based on the frequency of the electrical signal of the pressure sensor 10 in the open state, only a part of the introduction hole 31 is closed. Nevertheless, there is a risk of determining that it is in a closed state. Therefore, as described above, the threshold value is determined to be higher than the frequency of the electrical signal output from the pressure sensor 10 when the introduction hole 31 is not completely closed. By doing so, it is possible to suppress erroneous determination of the closed state of the introduction hole 31 compared to the above-described comparative configuration.

  The vibration part 40 is provided in the introduction hole 31. According to this, even if a foreign matter adheres in the introduction hole 31, the foreign matter can be removed by the vibration of the vibrating portion 40.

  The vibration part 40 is provided on the entire inner wall of the introduction hole 31. According to this, as compared with a configuration in which the vibration part is provided on a part of the inner wall of the introduction hole, the foreign matter attached in the introduction hole 31 can be removed regardless of the attachment location.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In the present embodiment, the configuration in which the vibration part 40 is provided on all the inner walls of the introduction hole 31 is shown. However, as shown in FIG. 7, a configuration in which the vibrating portion 40 is provided on a part of the inner wall of the introduction hole 31 may be employed. In particular, as shown in FIG. 7, in the case where the vibration part 40 is formed on one end side of the inner wall of the introduction hole 31, the vibration part is compared with the structure formed on the other end side of the inner wall of the introduction hole 31. It is suppressed that the vibration (the vibration different from the resonance frequency) having a specific frequency generated at 40 is transmitted to the pressure sensor 10. Therefore, a decrease in accuracy in determining whether one end of the introduction hole 31 is closed by a foreign object is suppressed. Further, as shown in FIG. 7, by forming the vibrating portion 40 in an annular shape, the foreign matter attached to one end of the introduction hole 31 can be reduced in place compared to the configuration in which the vibrating portion is formed in a C shape having a gap. It can be removed independently.

  In the present embodiment, the structure of the pressure sensor 10 is not particularly mentioned, but the configuration shown in FIG. 8 can be adopted. That is, it is possible to employ a configuration in which the strain gauge 10c is formed on the membrane 10b whose thickness is locally reduced in the semiconductor substrate 10a.

  In the present embodiment, an example in which the vibration part 40 is formed on the inner wall of the introduction hole 31 is shown. However, as shown in FIG. 8, a configuration in which the vibration part 40 is formed on the semiconductor substrate 10a may be employed. In the configuration shown in FIG. 8, the piezoelectric element 10e is formed on the membrane 10d having a locally thinned thickness in the semiconductor substrate 10a. As shown in FIG. 8, when the pressure sensor 10 and the vibration unit 40 are configured on one semiconductor substrate 10a, vibration generated in the vibration unit 40 is prevented from being directly transmitted to the pressure sensor 10 through the semiconductor substrate 10a. Therefore, a configuration in which a groove 10f is formed between the two is preferable.

  In the present embodiment, the configuration in which the vibration unit 40 is provided in the introduction hole 31 is shown. However, a configuration in which the vibration unit 40 is provided outside the introduction hole 31 may be employed. When the sensor device 100 is mounted on a vehicle, as the vibration unit 40, for example, as schematically illustrated in FIG. 9, a speaker 204 mounted on the vehicle can be employed. In the case of this modification, when the introduction hole 31 is in an open state, the fluid to be measured in the introduction hole 31 is vibrated by the vibration unit 40, and a standing wave is generated in the introduction hole 31. However, when the introduction hole 31 is blocked by a foreign substance, no stationary wave is generated in the introduction hole 31, and no pressure based on the resonance frequency is generated in the introduction hole 31. Therefore, the threshold value of the processing unit 20 is set lower than the frequency of the electrical signal output from the pressure sensor 10 in the open state and higher than the frequency of the electrical signal output from the pressure sensor 10 in the closed state. When the processing unit 20 determines that the frequency of the electrical signal output from the pressure sensor 10 is equal to or higher than the threshold, the processing unit 20 determines that the introduction hole 31 is in an open state, and the frequency of the electrical signal output from the pressure sensor 10 is When it is determined that the value is lower than the threshold value, the introduction hole 31 is determined to be in a closed state. The above-described speaker 204 employs a configuration having a sound source that is usually provided in a vehicle that performs music and voice notifications, and a transmission unit that transmits sound output from the sound source to the detected space 202. can do. For example, the speaker 204 may have a dedicated sound source that is different from the sound source normally provided in the vehicle.

  In addition, when the speaker 204 provided in the vehicle is employed as the vibration unit 40 as described above, the sensor device 100 is different from the configuration in which the vibration unit 40 is provided in the housing 30 separately from the speaker provided in the vehicle. An increase in the number of parts is suppressed.

  In this embodiment, the example which the process part 20 has a filter, a measurement part, and a comparison part was shown. However, the processing unit 20 is not limited to the above example. Although not shown, a configuration in which the processing unit 20 includes an F / V conversion circuit and a comparator may be employed. In this case, the frequency of the electric signal of the pressure sensor 10 is converted into a voltage by the F / V conversion circuit, and the converted voltage is input to the comparator. In addition to the voltage described above, a threshold voltage is input to the comparator. This threshold voltage corresponds to the threshold in this modification. For example, a configuration including a Fourier transform unit and a digital processing unit may be employed so that the processing unit 20 performs digital processing. As described above, various configurations can be adopted as the configuration for processing the frequency of the electrical signal of the pressure sensor 10.

  In the present embodiment, an example in which the sensor device 100 is provided on the inner panel 200 is shown. However, the attached member to which the sensor device 100 is attached and fixed is not limited to the above example, and is appropriately adopted depending on the application.

  In the present embodiment, an example in which each of the pressure sensor 10, the wiring board 11, the processing unit 20, and the capacitor 12 is electrically connected via the wire 13 has been described. However, a configuration in which the pressure sensor 10, the wiring board 11, the processing unit 20, and the capacitor 12 are electrically connected via solder (not shown) may be employed.

  In this embodiment, the example which the support part 34 comprised cyclic | annular form was shown. However, the shape of the support portion 34 is not limited to the above example.

  In this embodiment, the example in which each of the pressure sensor 10 and the processing unit 20 is covered and protected by the gel-like protection member 36 has been described. However, the protective member 36 may not be provided.

  In the present embodiment, the relationship between the shape of the introduction hole 31 and the standing wave is not specified. As shown in FIG. 4, the introduction hole 31 according to the present embodiment has an almost constant inner diameter, but is L-shaped and bent in the zx plane. Therefore, when sound is generated in the introduction hole 31, pressure loss occurs due to the bending. However, after all, only a specific frequency according to the shape of the introduction hole 31 is emphasized, and as shown in FIGS. 5 and 6, the introduction hole 31 is not bent. Similarly, a standing wave is generated in the introduction hole 31. Therefore, the shape of the introduction hole 31 can be appropriately adopted as long as one end and the other end communicate with each other.

  Further, in the present embodiment, the specific configuration of the vibrating portion 40 provided in the introduction hole 31 is not particularly described in detail. As this vibration part 40, an ultrasonic transducer having a piezoelectric effect can be employed. This ultrasonic transducer is composed of two electrodes and a piezoelectric material provided between the electrodes. The two electrodes described above are arranged in the radial direction of the introduction hole 31 through the piezoelectric material, and are formed in a tubular shape following the shape of the inner wall of the introduction hole 31. As such a flexible piezoelectric material, for example, a piezoelectric polymer film can be employed. When an electric signal whose amplitude fluctuates from positive to negative at a constant period is input to the piezoelectric polymer film, the piezoelectric polymer film expands and contracts in the radial direction, and a sound corresponding to the frequency of the electric signal is generated from the vibration unit 40 and introduced. A standing wave is generated in the hole 31. Strictly speaking, the piezoelectric polymer film also vibrates in the circumferential direction of the introduction hole 31 when expanding and contracting in the radial direction. Therefore, strictly speaking, the vibrating portion 40 has a tube shape having a gap as play for vibrating in the circumferential direction. Moreover, although this was shown in this embodiment, the input of the electric signal for generating this standing wave to the vibration part 40 is performed when the introduction hole 31 is inspected. And the process part 20 may have a production | generation circuit which produces | generates this electrical signal, and another member may have.

  As described above, in the present embodiment, as shown in FIG. 4, the example in which the vibration part 40 is provided on the entire inner wall of the introduction hole 31 is shown. In this case, the vibration part 40 is generated by the vibration part 40 over the entire area of the introduction hole 31. Sounds. Therefore, strictly speaking, the complete standing wave schematically shown in FIGS. However, the frequency of the sound in the introduction hole 31 always changes depending on whether the introduction hole 31 is in an open state or a closed state. Therefore, as shown in the present embodiment, based on the frequency of the electrical signal from the pressure sensor 10, it can be determined whether or not the introduction hole 31 is blocked by a foreign substance.

DESCRIPTION OF SYMBOLS 10 ... Pressure sensor 20 ... Processing part 30 ... Housing 31 ... Introduction hole 40 ... Vibrating part 100 ... Sensor apparatus

Claims (11)

A pressure sensor (10) for converting the pressure of the fluid to be measured into an electrical signal;
A processing unit (20) for processing an electrical signal of the pressure sensor;
A housing (30) in which the pressure sensor and the processing unit are housed, and an introduction hole (31) for guiding the fluid to be measured to the pressure sensor is formed;
And a vibrating section (40, 204) for generating a standing wave having a resonance frequency determined by the shape and state of the introduction hole by vibrating the fluid to be measured in the introduction hole. And
One end of the introduction hole is opened, the other end is closed, and the pressure sensor is provided in the housing so that the pressure sensor can detect the pressure of the fluid to be measured in the introduction hole at the other end. And
The pressure sensor outputs an electrical signal whose amplitude periodically varies according to the resonance frequency when the standing wave is generated in the introduction hole by the vibration unit,
The processing unit determines whether the introduction hole is blocked by a foreign substance based on a frequency of an electric signal of the pressure sensor according to the resonance frequency. The processing unit has a threshold based on a frequency of an electric signal output from the pressure sensor when the introduction hole is not completely blocked by the foreign matter,
The said processing part determines whether the said introduction hole is obstruct | occluded by the said foreign material based on the magnitude relationship between the frequency of the electrical signal output from the said pressure sensor, and the said threshold value. 2. The sensor device according to 1.   The sensor device according to claim 2, wherein the vibration unit is provided in the introduction hole. The threshold is higher than the frequency of the electrical signal output from the pressure sensor when the introduction hole is open, and the electrical signal output from the pressure sensor when the introduction hole is blocked by the foreign matter. Is set lower than the frequency of
When the processing unit determines that the frequency of the electrical signal output from the pressure sensor is lower than the threshold value, the processing unit determines that the introduction hole is not blocked by the foreign matter, and outputs the electrical signal output from the pressure sensor. The sensor device according to claim 3, wherein when it is determined that the frequency of the signal is equal to or higher than the threshold value, the introduction hole is determined to be blocked by the foreign matter.   The sensor device according to claim 3, wherein the vibration portion is provided on the one end side of the inner wall of the introduction hole.   The sensor device according to claim 5, wherein the vibrating portion is provided not only on one end side of the inner wall of the introduction hole but on the entire surface. The vibrating portion is provided outside the introduction hole,
The threshold is lower than the frequency of an electrical signal output from the pressure sensor when the introduction hole is not blocked by the foreign matter, and is output from the pressure sensor when the introduction hole is closed by the foreign matter. Is set higher than the frequency of the electrical signal
When the processing unit determines that the frequency of the electrical signal output from the pressure sensor is equal to or higher than the threshold value, the processing unit determines that the introduction hole is not blocked by the foreign matter, and outputs the electrical signal output from the pressure sensor. 3. The sensor device according to claim 2, wherein when the frequency of the signal is determined to be lower than the threshold value, it is determined that the introduction hole is blocked by the foreign matter.   The sensor device according to claim 7, wherein the vibration unit is a speaker (204) provided in a vehicle.   The said measured fluid is the air of the space (202) comprised between the inner panel (200) and outer panel (201) of a vehicle, The any one of Claims 1-8 characterized by the above-mentioned. Sensor device.   The sensor device according to claim 9, wherein the pressure sensor outputs an electric signal corresponding to a pressure fluctuation of the fluid to be measured to a control circuit (203) that controls an airbag system of the vehicle. An insertion portion (39) for fixing the housing to the inner panel;
A seal member (38) provided between the housing and the inner panel;
The sensor device according to claim 9, wherein the seal member is made of an elastic material.

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