JP2007192553A - Tilt sensor and tilt angle measuring method - Google Patents

Abstract

A tilt sensor as a level and a tilt angle measurement method capable of measuring a tilt angle with high accuracy by increasing the resolution for electrical detection.
A tilt sensor 10 includes a cantilever portion 30 that converts a tilt into a force in a predetermined direction, a double tuning fork vibrator 20 that is connected to the cantilever portion 30 and changes a resonance frequency upon receiving the force, and a cantilever portion 30. And a control circuit unit 29 including a circuit for calculating an inclination angle based on a change in the resonance frequency of the double tuning fork vibrator 20 are accommodated in the recess 12 of the storage container 11 serving as a base. Yes. The opening part of the recessed part 12 of the storage container 11 is airtightly sealed with the cover body 31 as a sealing part.
[Selection] Figure 1

Description

  The present invention relates to a tilt sensor that is placed on a surface to be measured of a structure and electrically measures the inclination of the surface to be measured, and a method for measuring a tilt angle.

  In order to obtain the level or verticality of a structure such as a building, there is a level that is placed on a plane that is a surface to be measured of the structure and detects the inclination of the surface. In recent years, a level (tilt sensor) that electrically measures the magnitude of tilt as disclosed in Patent Document 1 has been proposed.

  The level shown in Patent Document 1 will be described with reference to FIG. FIG. 13 is a front view showing a schematic configuration of a conventional level. Referring to FIG. 13, a conventional level 1000 includes a main body 1010 having a mounting surface 1016 that includes a small sphere 1011, a tube 1012 formed in an arc shape, and an array along the outer wall of the tube 1012. And a sensor array 1014 made up of a plurality of sensors 1013. The small sphere 1011 has buoyancy and is provided so that the tube 1012 can freely move in the tube 1012 when the tube 1012 is inclined. Further, the main body 1010 is provided with an electronic circuit unit 1015 that processes the measurement signal and calculates the magnitude (angle) of the tilt.

  A method for detecting the inclination of the level 1000 will be described. First, a plurality of sensors 1013 are scanned while being sequentially switched, a pulse signal is transmitted into the tube 1012, and a sensor 1013 a facing the small sphere 1011 is detected depending on the presence or absence of a reflection signal or transmission signal from the small sphere 1011 in the tube 1012. To detect. Based on the detected position of the sensor 1013a, the electronic circuit unit 1015 calculates the magnitude of the inclination.

JP-A-11-166829

  However, in the conventional level 1000, since each of the plurality of sensors 1013 has a predetermined length, even if the position of the small sphere 1011 is changed, it is between the length directions of the respective sensors 1013. The detected sensor 1013 does not change. In other words, the adjacent sensor 1013 is not detected unless the position of the small sphere 1011 moves until the position of each sensor 1013 arranged in sequence is exceeded. In other words, the conventional level 1000 has a problem that since the detection waveform is stepped, the detection resolution is low, and it is difficult to measure a tilt angle with higher accuracy.

  The present invention has been made to solve the above-described problems, and provides a tilt sensor as a level and a tilt angle measuring method capable of measuring a tilt angle with high accuracy by increasing the resolution of electrical detection. The purpose is to do.

  The tilt sensor according to the present invention is connected to the fixing portion via the supporting portion, the fixing portion fixed to the base, the flexible supporting portion connected to the fixing portion, and the supporting portion. A swinging portion movable by flexibility; a pair of vibrating arms; and a base portion extending at each end of the vibrating arm, the direction intersecting the moving direction of the swinging portion being A double tuning fork vibrator in which one of the bases is fixed to the fixed part and the other of the bases is fixed to the swinging part so as to be in a vibration direction; and a drive circuit unit that oscillates the double tuning fork vibrator; And a control circuit unit including an arithmetic circuit unit that calculates an inclination angle based on a change in the resonance frequency of the double tuning fork vibrator.

  According to the tilt sensor of the present invention, the tilt angle measurement resolution can be increased, and a tilt sensor capable of measuring a tilt angle with high accuracy can be provided. The tilt sensor of the present invention has a fixed portion fixed to a base and a swinging portion connected via a flexible support portion. The swinging part can move due to the flexibility of the support part, and by tilting the base, the swinging part tends to move in the rotational direction so as to balance gravity with the vicinity of the support part as a fulcrum. Force (hereinafter referred to as “force”) is generated. In the double tuning fork vibrator, the base part is fixed to the fixed part and the swinging part so as to receive this force in a direction crossing the vibration direction of the vibrating arm, and the resonance frequency depends on the magnitude of the received force. Quantitative change. Since this force changes with the tilt angle of the base, the control circuit section measures the amount of change in the resonant frequency of the double tuning fork vibrator, and calculates the tilt angle based on the measured amount of change in the resonant frequency. It becomes possible to do. Since the change in the resonance frequency of the double tuning fork vibrator changes continuously with the change in the tilt angle, it becomes possible to provide a tilt sensor capable of measuring the tilt angle with high accuracy by increasing the tilt angle measurement resolution. .

  Moreover, it is desirable that the fixed portion, the support portion, and the swing portion are integrally formed.

  In this way, by forming integrally from one material, each connection becomes unnecessary and simple formation becomes possible.

  Further, it is preferable that a weight portion is formed on the swinging portion on the opposite side of the connecting side of the double tuning fork vibrator and the support portion.

  In this way, since the weight of the weight is added to the weight of the swinging part, the weight of the swinging part is increased, and the force generated by giving an inclination increases. As a result, the amount of change in the resonance frequency of the double tuning fork vibrator is increased, and the sensitivity of detecting the tilt angle can be increased.

  It is desirable that the support portion, the swinging portion, and the weight portion are held hollow.

  In this way, since the tilted swinging part and the weight part can freely move, the generated force can be transmitted to the double tuning fork vibrator as it is without being attenuated. That is, it is possible to increase the measurement accuracy of the tilt angle.

  The base is a storage container in which a recess having an opening on at least one surface is formed. Inside the storage container, the fixing part, the support part, the swing part, and the double part are provided. It is desirable that a tuning fork vibrator and the control circuit unit are accommodated, and the opening is closed by a sealing unit.

  In this way, since the tilt angle measurement part and the control circuit are housed in the same storage container, it is possible to provide a tilt sensor capable of collectively performing the tilt angle measurement and the arithmetic processing. .

  Further, the storage container is formed with a front-side recess and a back-side recess each having an opening on the front and back surfaces, and the front-side recess includes the fixing portion, the support portion, the swinging portion, It is preferable that a double tuning fork vibrator is accommodated, the control circuit portion is accommodated in the back-side recess, and each opening is closed by a sealing portion.

  If it does in this way, it will be possible to process a front side crevice and a back side crevice separately, respectively, and it will become possible to perform adjustment which raised more accuracy.

  It is preferable that the concave portion in which the double tuning fork vibrator is accommodated is closed in a low pressure state by the sealing portion.

  In this way, it is possible to suppress the air resistance that inhibits the vibration of the double tuning fork vibrator, and to obtain more stable vibration characteristics of the double tuning fork vibrator.

  The tilt angle measuring method according to the present invention is connected to a fixed portion fixed to a base, and is generated by a swinging portion provided via a flexible support portion. The bases formed at both ends of the vibrating arm are configured so that the direction in which the moving part moves is intersected with the moving direction of the swinging arm is the vibrating direction of the vibrating arm. Measure the change in the resonance frequency of the double tuning fork vibrator, which changes depending on the magnitude of the transmitted force, and tilt based on the change in the measured resonance frequency. It is characterized by calculating the size of.

  According to the tilt angle measuring method of the present invention, the tilt angle measurement resolution can be increased, and a tilt measuring method capable of measuring a tilt angle with high accuracy can be provided. The tilt angle measuring method according to the present invention transmits a force that the fixed part fixed to the base and the swinging part connected via the flexible support part move due to the tilt of the base. It is calculated based on the change in the resonance frequency of the obtained double tuning fork vibrator. This force changes continuously with the tilt angle of the base, and the resonance frequency of the double tuning fork vibrator also changes according to the magnitude of this force, so the tilt angle measurement resolution increases and the tilt angle is measured with high accuracy. It becomes possible.

The best mode of the tilt sensor according to the present invention will be described below with reference to the drawings.
(First embodiment)

  First, the configuration of the tilt sensor according to the first embodiment will be described with reference to FIGS. 1, 2, and 3. FIG. 1 is a plan view schematically showing the tilt sensor of the first embodiment. FIG. 2 is a front view showing a cross section AA of FIG. FIG. 3 is a right side view showing the BB cross section of FIG. 1.

  As shown in FIGS. 1, 2, and 3, the tilt sensor 10 includes a cantilever part 30 that converts the tilt into a force in a predetermined direction, and a double tuning fork vibrator 20 and a weight part 27 connected to the cantilever part 30. The control circuit unit 29 is accommodated in the recess 12 of the storage container 11 as a base. The opening part of the recessed part 12 of the storage container 11 is airtightly sealed with the cover body 31 as a sealing part.

Next, details of the constituent parts of the tilt sensor 10 will be described sequentially. First, an outline of the double tuning fork vibrator 20 will be described. Details of the configuration, operation, and the like will be described later.
The double tuning fork vibrator 20 uses, for example, a so-called Z plate crystal whose thickness direction is the Z axis (optical axis) of the crystal axis, and two (a pair) of vibrating arms 21 extending in the Y axis direction (mechanical axis). And bases 22a and 22b that support both ends of the vibrating arm 21, respectively. The vibrating arm 21 vibrates in the X-axis (electric axis) direction.

  Next, the cantilever part 30 will be described. The cantilever part 30 includes a fixed part 14, a support part 19, and a swing part 17. The cantilever part 30 is integrally formed by cutting a flexible material such as phosphor bronze or spring stainless steel. In addition, although the fixing | fixed part 14, the support part 19, and the rocking | swiveling part 17 can each be formed and connected separately, if it forms integrally from one material like this 1st embodiment, it is. Each connection is not necessary, and it is suitable for simple formation.

  The fixing portion 14 is fixed to the bottom surface 13 of the concave portion 12 of the storage container 11 by a fixing bolt 15 or the like. At this time, the fixing portion 14 is fixed so that the connection position of the support portion 19 of the cantilever portion 30 and the weight portion 27 is on the perpendicular line of the placement surface 11a for placing the storage container 11 on the object to be measured. . One surface of the fixed portion 14 is formed with a surface 14 a of the fixed portion 14 and a stepped bottom surface 24, and one base portion 22 b of the double tuning fork vibrator 20 is fixed to the bottom surface 24. Further, the fixed portion 14 is formed with a protruding portion 16 that extends in substantially the same direction as the extending direction of the vibrating arm 21 of the double tuning fork vibrator 20. At one end of the projecting portion 16, a support portion 19 extending in a direction intersecting with the extending direction of the projecting portion 16 is formed.

  The support portion 19 has, for example, a thin shape (plate spring shape) with a width dimension of about 0.2 mm. The support portion 19 has a so-called flexibility (spring property) that can be bent with the vicinity of the intersection with the protruding portion 16 as a fulcrum by this thin shape (plate spring shape). One end of the support portion 19 is connected to a protruding portion 18 formed so as to protrude from the swinging portion 17 toward the fixed portion 14. The support part 19 and the protrusion part 18 are connected in a direction in which the protrusion direction of the protrusion part 18 and the extending direction of the support part 19 intersect.

  A weight fixing portion 25 is formed around one of the swinging portions 17 so as not to come into contact with the protruding portion 16, and the weight portion 27 is fixed to the weight fixing portion 25 with a fixing bolt 26 or the like. Has been. The swinging portion 17, the projecting portion 18, and the weight portion 27 can freely move as the flexible support portion 19 is bent. In addition, the support part 19, the rocking | swiveling part 17, the protrusion part 18, and the weight part 27 are hold | maintained hollowly in order to prevent the movement resistance by a contact with another structure part. Further, on the other side of the oscillating portion 17, a surface 17 a of the oscillating portion 17 and a stepped bottom surface 23 are formed, and one base portion 22 a of the double tuning fork vibrator 20 is fixed to the bottom surface 23. The other of the above-described swinging portion 17 is a portion that is near the opposite end portion across the weight portion 27 and the support portion 19 and that faces the stepped bottom surface 24 formed on the fixed portion 14.

  In the double tuning fork vibrator 20, the base portions 22 b and 22 a are fixed to the bottom surface 24 of the fixed portion 14 and the bottom surface 23 of the swinging portion 17 so that the vibrating arm 21 is held hollow. As a result, the fixed portion 14 and the swinging portion 17 are connected in a bridging manner by the double tuning fork vibrator 20.

  The storage container 11 to which the above-described cantilever part 30 is fixed has a recess 12 having an opening on the surface of a metal plate such as stainless steel or aluminum. The recess 12 has a multi-stage shape in which two bottom surfaces 13 and 28 are provided, and the bottom surface 28 is formed deeper than the bottom surface 13. This is to hold the swinging portion 17, the weight portion 27, and the double tuning fork vibrator 20 in the cantilever portion 30 in which the fixing portion 14 is fixed to the bottom surface 13. Further, a control circuit unit 29 is connected to the bottom surface 28 so as not to contact the swinging unit 17, the weight unit 27, and the double tuning fork vibrator 20.

A lid 31 is airtightly joined to the upper surface 33 of the outer frame portion 32 of the storage container 11 so as to cover the opening of the recess 12 of the storage container 11. At this time, the concave portion 12 is in a low pressure state having a degree of vacuum of, for example, 1 × 10 ⁻¹ Pa (pascal) or less. This is because the vibration efficiency of the double tuning fork vibrator 20 is increased (vibration characteristics are improved).

Next, the control circuit unit 29 will be described. The configuration of the control circuit unit 29 is shown in the block diagram of FIG. As shown in FIG. 4, a drive circuit unit 50 connected to the double tuning fork vibrator 20, a detection circuit unit 51 that detects a change in the resonance frequency of the double tuning fork vibrator 20 output from the drive circuit unit 50, and a detection An arithmetic circuit unit 52 that calculates an angle of inclination based on information with the circuit unit 51 is provided. The control circuit unit 29 is composed of, for example, a semiconductor circuit chip or a circuit board on which various circuit elements are mounted, and is fixed to the bottom surface 28 of the recess 12 of the storage container 11.
It is also possible to connect to a display unit 53 that displays information output from the arithmetic circuit unit 52. In this case, although not shown, the display unit 53 may be provided in the storage container 11 or the lid 31, and may be provided separately from the inclination sensor 10.

  Next, a detailed configuration and operation of the double tuning fork vibrator 20 will be described with reference to FIGS. 5 and 6. FIG. 5 is a schematic view showing the electrode shape of the double tuning fork vibrator. FIG. 6 is a schematic diagram showing a vibration form of the double tuning fork vibrator.

  The double tuning fork vibrator 20 is formed of a piezoelectric base material such as quartz. The double tuning fork vibrator 20 of the first embodiment is a double tuning fork crystal vibrator using a quartz base material having a thickness of about 0.1 mm. In the double tuning fork vibrator 20, the Z′-axis direction rotated by a predetermined angle around the crystal axis of the crystal is the thickness direction, and two vibrating arms 21 aligned in the X-axis direction extend in the Y-axis direction. Both ends of the vibrating arm 21 are connected to the base portions 22a and 22b.

  Excitation electrodes 46 and 47 as examples of electrode shapes for exciting the vibrating arm 21 are formed on the surface of the vibrating arm 21. The excitation electrodes 46 and 47 are close to the connection portions between the electrodes 40 and 41 provided at the center of the respective vibrating arms 21 and the bases 22a and 22b of the vibrating arms 21 (parts on both sides of the electrodes 40 and 41). And electrodes 42, 43, 44, 45. Although not shown, excitation electrodes having the same configuration are also formed on the back surface of the vibrating arm. In addition, excitation electrodes may be provided on the side surfaces.

  The vibration will be described with reference to FIG. First, as shown in FIG. 6B, a negative (−) potential is applied to the electrode 40 constituting one excitation electrode 46, and a positive (+) potential is applied to the electrode 42 and the electrode 43. At the same time, a positive (+) potential is applied to the electrode 41 constituting the other excitation electrode 47, and a negative (−) potential is applied to the electrode 44 and the electrode 45. By applying such a potential, the respective vibrating arms 21 that have been in a substantially parallel state as shown in FIG. 6A bend outward as shown in FIG. 6B.

  Subsequently, as shown in FIG. 6C, a potential opposite to the potential of FIG. 6B is applied to each electrode. That is, a positive (+) potential is applied to the electrode 40 constituting one excitation electrode 46, and a negative (−) potential is applied to the electrode 42 and the electrode 43. At the same time, a negative (−) potential is applied to the electrode 41 constituting the other excitation electrode 47, and a positive (+) potential is applied to the electrode 44 and the electrode 45. By applying such a potential, each vibrating arm 21 bends inward as shown in FIG.

  By repeatedly applying the potentials shown in FIGS. 6B and 6C, the vibrating arm 21 vibrates at a predetermined resonance frequency. In the first embodiment, the double tuning fork vibrator 20 formed so that the resonance frequency is about 40 KHz is used.

  As described above, when a compression force is applied to the double tuning fork vibrator 20 that vibrates at a predetermined resonance frequency in a direction crossing the vibration direction of the vibrating arm 21, or a pulling force is applied to the double tuning fork vibrator 20, the resonance frequency is obtained. Changes. The tilt sensor 10 shown in the first embodiment uses the characteristics of the double tuning fork vibrator 20, and this measurement method will be described with reference to FIGS. FIGS. 7A and 7B are operation explanatory views showing an outline of the measurement method, in which FIG. 7A shows a case where the measured portion has no inclination, and FIG. 7B shows a case where the measured portion has a counterclockwise inclination. (C) shows the case where the part to be measured has a clockwise inclination. FIG. 8 is a graph showing a change in frequency of the double tuning fork vibrator when a force is applied.

  The method for measuring the tilt angle will be described with reference to FIG. 7, but the storage container is omitted in the figure. When the fixing bolt 26 of the support portion 19 and the weight portion 27 is on the vertical line 55 shown in FIG. 7A, that is, when the cantilever portion 30 is not inclined, no moving force is generated in the swing portion 17. Therefore, no force is applied to the double tuning fork vibrator 20.

  When the cantilever portion 30 shown in FIG. 7B is tilted by the angle θ1 in the counterclockwise direction, the oscillating portion 17 to which the weight portion 27 is connected is supported by the fulcrum Q near the intersection with the fixed portion 14 of the support portion 19 due to gravity. A force is generated to move in the direction of the arrow R1 around the center. At this time, since the oscillating portion 17 is connected to the fixed portion 14 in a bridging manner by the double tuning fork vibrator 20, the oscillating portion 17 does not actually move, and the force to move is indicated by the arrow P1. Is applied to the double tuning fork vibrator 20 as a force in the direction, i.e., a compression force. In other words, the compression force applied in the direction of the arrow P <b> 1 is applied in a direction crossing the vibration direction of the vibrating arm 21 of the double tuning fork vibrator 20.

  Further, as shown in FIG. 7C, when the cantilever portion 30 is inclined clockwise by an angle θ2, the swinging portion 17 to which the weight portion 27 is connected is near the intersection with the fixed portion 14 of the support portion 19 due to gravity. A force is generated to move in the direction of the arrow R2 around the fulcrum Q. At this time, since the oscillating portion 17 is connected to the fixed portion 14 in a bridging manner by the double tuning fork vibrator 20, the oscillating portion 17 does not actually move, and the force to move is indicated by the arrow P2. Is applied to the double tuning fork vibrator 20 as a force in the direction, i.e., a pulling force.

  The double tuning fork vibrator 20 has a characteristic that when a compression force is applied in a direction crossing the vibration direction of the vibrating arm 21, the resonance frequency decreases, and conversely, when a tensile force is applied, the resonance frequency increases. Yes. Therefore, when the angle θ1 is given to the cantilever portion 30 in the direction shown in FIG. 7B, the resonance frequency of the double tuning fork vibrator 20 is lowered. This change in the resonance frequency is substantially proportional to the magnitude of the force applied to the double tuning fork vibrator 20 and causes a change of about 10% in the resonance frequency. Since the compression and pulling force described above varies depending on the inclination of the cantilever portion 30, the amount of change in the resonance frequency of the double tuning fork vibrator 20 varies depending on the inclination. Therefore, the inclination of the cantilever part 30 can be measured by detecting the amount of change in the resonance frequency.

  FIG. 8 shows the result of measuring the correlation between the tilt angle of the cantilever part 30 and the change in the resonance frequency of the double tuning fork vibrator 20. The vertical axis in FIG. 8 indicates the amount of change in the resonance frequency of the double tuning fork vibrator 20, and the horizontal axis indicates the inclination of the cantilever portion 30. As shown in FIG. 8, the change in the resonance frequency is small in the range where the inclination of the cantilever portion 30 is small, and the amount of change in the resonance frequency increases as the inclination increases. The inclination is 90 degrees and shows the maximum value.

According to the above-described inclination sensor 10 of the first embodiment, the fixing portion 14 of the cantilever portion 30 is fixed to the concave portion 12 of the storage container 11, and the fixing portion 14 and the flexible support portion 19 are interposed therebetween. The rocking part 17 is connected. When the storage container 11 is tilted, that is, when the mounting surface 11a of the storage container 11 is placed on a measured surface having an inclination, gravity and fishing are supported on the swinging part 17 with the vicinity of the support part 19 as a fulcrum Q. A force is generated to try to move in the direction of rotation to fit. The double tuning fork vibrator 20 having the base portions 22a and 22b fixed to the fixed portion 14 and the swinging portion 17 so as to receive this force in a direction intersecting with the vibration direction of the vibrating arm 21 receives the force received. The resonance frequency of the double tuning fork vibrator 20 changes by a predetermined amount depending on the size. Since this force changes with the inclination angle of the mounting surface 11a of the storage container 11, the amount of change in the resonance frequency of the double tuning fork vibrator 20 is measured by the control circuit unit 29, and the change in the measured resonance frequency is measured. The tilt angle can be calculated based on the amount. Since the change in the resonance frequency of the double tuning fork vibrator 20 changes continuously with the change in the tilt angle, the tilt angle can be measured continuously, in other words, the measurement resolution can be increased. It becomes. Accordingly, the tilt sensor 10 shown in the first embodiment can measure a tilt angle with high accuracy.
(Second embodiment)

  The configuration of the tilt sensor according to the second embodiment will be described with reference to FIGS. FIG. 9 is a plan view schematically showing the tilt sensor according to the second embodiment. FIG. 10 is a front view showing the AA cross section of FIG. 9.

  As shown in FIGS. 9 and 10, the tilt sensor 70 includes a cantilever portion 80 that converts the tilt into a force in a predetermined direction, the double tuning fork vibrator 20 and the weight portion 27 that are connected to the cantilever portion 80, and a control circuit. The portion 69 is stored in the storage container 61. The cantilever portion 80 is fixed by a fixing bolt 15 to the bottom surface 71 of the front-side recess 62 in which the fixing portion 14 is opened on the front surface side of the storage container 61. The cantilever part 80, and the double tuning fork vibrator 20 and the weight part 27 connected to the cantilever part 80 are housed in the front side recessed part 62 and serve as a sealing part joined to the surface 74 of the outer frame 73 of the housing container 61. The lid 68 is hermetically sealed. The control circuit unit 69 is joined to the bottom portion 65 of the back-side recess 64 opened on the back side of the storage container 61 using a conductive adhesive or the like, and is sealed to the back surface 75 of the outer frame 73 portion of the storage container 61. It is hermetically sealed by a lid 76 as a stop.

  The front-side recess 62 on the front side in which the cantilever part 80 is accommodated and the back-side recess 64 on the back side in which the control circuit part 69 is accommodated connect the front-side recess 62 and the back-side recess 64 to the step part 63a of the storage container. Electrical connection is established by hermetic seal portions 66 and 67 provided at 63b. As a result, it is possible to send and receive data between various components and elements housed in the front side recess 62 side and the back side recess 64 side.

  The cantilever part 80, the double tuning fork vibrator 20 and the weight part 27 have the same configuration as that of the first embodiment described above, and therefore the description thereof in the second embodiment is omitted. The tilt angle measuring method is the same as that of the first embodiment described above, and the description of the second embodiment is omitted.

  According to the inclination sensor 70 of the second embodiment described above, different components are accommodated in the two recesses 62 and 64 in addition to the effects of the first embodiment described above. Accordingly, it is possible to perform processing and adjustment for each of the concave portions 62 and 64, and it is possible to provide the tilt sensor 70 having a higher tilt angle measurement accuracy.

  In the above-described embodiment, the example has been described in which the lids 31, 68, 76 are used as the sealing portions of the opening portions of the storage containers 11, 61, but other forms may be used as the sealing portions. For example, a filled resin or the like may be used.

  Further, in the first embodiment and the second embodiment described above, the supporting portion 19 and the fixing portion of the weight portion 27 are provided in a direction (vertical direction) substantially perpendicular to the placement surfaces 11a and 61a of the storage containers 11 and 61. Although the case has been described and described, the present invention is not limited to this. As shown in FIG. 11, an imaginary line connecting the support part 19 and the fixing bolt 26 of the weight part 27 with respect to the mounting surface 11 a of the storage container 11 by the fixing part 14 of the cantilever part 30 is, for example, a predetermined angle. May be fixed. In this example, an example in which the angle between the placement surface 11a and the virtual line is 45 degrees is shown.

  FIG. 12 shows the correlation between the inclination of the inclination sensor 60 shown in FIG. 11 and the amount of change in the resonance frequency of the built-in double tuning fork vibrator 20. As shown in FIG. 12, the tilt sensor 60 shown in FIG. 11 can increase the amount of frequency change for each tilt angle when the tilt is near 0 degrees (horizontal state). That is, the measurement sensitivity with respect to the tilt angle can be increased.

Moreover, although the double tuning fork vibrator 20 has been described by using a Z-plate crystal, the present invention is not limited thereto, and may be formed using other piezoelectric materials. Examples of the piezoelectric material include zinc oxide (ZnO), lithium tantalate (LiTaO ₃ ), lead zirconate titanate (PZT), and lithium niobate (LiNbO ₃ ).

The top view which shows the outline of the inclination sensor of 1st embodiment. The front view which shows the AA cross section of FIG. The right view which shows the BB cross section of FIG. The block diagram which shows the structure of a control circuit part. Schematic which shows the electrode shape of a double tuning fork vibrator. The schematic diagram which shows the vibration form of a double tuning fork vibrator. Operation | movement explanatory drawing which shows the outline of a detection method. The graph which shows the correlation of the inclination angle of a cantilever part, and the change of the resonant frequency of a double tuning fork vibrator. The top view which shows the outline of the inclination sensor of 2nd embodiment. The front view which shows the AA cross section of FIG. The top view which shows an example of the inclination sensor by which the mounting surface of the storage container and the cantilever part are arrange | positioned at an angle of 45 degree | times. The graph which shows the correlation with the inclination angle of the inclination sensor shown in FIG. 11, and the resonant frequency of a double tuning fork vibrator. The front view which shows the structure of the outline of the conventional level.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Inclination sensor, 11 ... Storage container as a base, 11a ... Mounting surface, 12 ... Recessed part, 13, 23, 24, 28 ... Bottom, 14 ... Fixed part, 14a ... Surface of fixed part, 15, 26 ... Fixing bolt, 16, 18 ... projecting part, 17 ... swinging part, 17a ... surface of swinging part, 19 ... support part, 20 ... double tuning fork vibrator, 21 ... vibrating arm, 22a, 22b ... base, 25 ... weight Fixed part, 27 ... weight part, 29 ... control circuit part, 30 ... cantilever part, 31 ... lid as sealing part, 32 ... frame part, 33 ... frame part upper surface.

Claims (8)

A fixed part fixed to the base;
A flexible support connected to the fixed part;
An oscillating part connected to the fixed part via the support part and movable by the flexibility of the support part;
One of the bases has a pair of resonating arms and bases extending at both ends of the resonating arms, and the direction intersecting the moving direction of the swinging part is the vibration direction of the resonating arms. A double tuning fork vibrator fixed to the fixed part and the other of the base part fixed to the swing part;
And a control circuit unit including a drive circuit unit that oscillates the double tuning fork vibrator and an arithmetic circuit unit that calculates an inclination angle based on a change in the resonance frequency of the double tuning fork vibrator. Tilt sensor. The tilt sensor according to claim 1,
The tilt sensor, wherein the fixed portion, the support portion, and the swinging portion are integrally formed. The tilt sensor according to claim 1 or 2,
The tilt sensor is characterized in that a weight portion is formed on the swinging portion on the opposite side of the connecting portion of the double tuning fork vibrator and the support portion. The inclination sensor according to any one of claims 1 to 3,
The tilt sensor, wherein the support portion, the swinging portion, and the weight portion are held hollow. The tilt sensor according to any one of claims 1 to 4,
The base is a storage container in which a recess having an opening on at least one surface is formed,
In the storage container, the fixed portion, the support portion, the swinging portion, the double tuning fork vibrator, and the control circuit portion are stored,
The opening sensor is closed by a sealing portion. The inclination sensor according to any one of claims 1 to 5,
The storage container has a front side recess and a back side recess each having an opening on the front and back surfaces,
In the front side recess, the fixed portion, the support portion, the swinging portion, and the double tuning fork vibrator are stored, and in the back side recess, the control circuit unit is stored,
Each of the openings is closed by a sealing portion. The tilt sensor according to claim 5 or 6,
The inclination sensor, wherein the concave portion in which the double tuning fork vibrator is accommodated is closed in a low pressure state by the sealing portion. Connected to the fixed part fixed to the base and generated in the swing part provided via the flexible support part, the force that the swing part tries to move when the base tilts,
A double tuning fork vibrator in which base portions formed at both ends of the vibrating arm are fixed to the fixed portion and the swinging portion so that a direction intersecting the moving direction of the swinging portion is a vibration direction of the vibrating arm. Measuring a change in the resonance frequency of the double tuning fork vibrator that varies depending on the magnitude of the transmitted force, and calculating a magnitude of the inclination based on the change in the measured resonance frequency. To measure the tilt angle.

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