JP2012063242A - Angular velocity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an angular velocity sensor for attenuating vibration in all 3-axis directions so that vibration in a Y axis direction and a Z axis direction added from outside are attenuated.SOLUTION: A mounting member 80 is supported by a terminal 81 electrically connected to a terminal electrode 75 from its surroundings and the terminal 81 is provided with an X-axis direction extension part 84, a Y-axis direction extension part 82, and a Z-axis extension part 83.

Description

  The present invention particularly relates to an angular velocity sensor used for attitude control of a moving body such as an aircraft or a vehicle, a navigation system, or the like.

  This type of conventional angular velocity sensor has a configuration as shown in FIGS.

  8 is an exploded perspective view of a conventional angular velocity sensor, FIG. 9 is a top cross-sectional view of the angular velocity sensor, FIG. 10 is a perspective view of a storage portion of the angular velocity sensor viewed from below, and FIG. 11 is a case of the angular velocity sensor. FIG. 12 is a perspective view of the same angular velocity sensor as viewed from below.

  8 to 12, reference numeral 21 denotes a tuning fork-shaped vibrator. Reference numeral 30 denotes a case made of ceramic. The case 30 is provided with a multilayer circuit board 31 having a layer structure of ceramics and wiring conductors from the inner bottom surface to the outer bottom surface, and on the upper surface of the multilayer circuit board 31, FIG. As shown, the first wiring electrode 32 and the second wiring electrode 33 are provided. An IC 35 electrically connected to the first wiring electrode 32 and a wire wire 34 made of gold or aluminum is provided on the upper surface of the multilayer circuit board 31, and the second wiring electrode 33 is electrically connected to the first wiring electrode 32. A capacitor 36 connected to is provided. The IC 35 is housed inside the case 30 and processes an output signal output from the vibrator 21. Further, as shown in FIG. 12, the case electrode 37 made of six silver is provided on the outer bottom surface of the multilayer circuit board 31 in the case 30 and the outer periphery of the upper surface of the multilayer circuit board 31 is provided as shown in FIG. A side wall 38 made of ceramic is provided, and a metal frame 39 made of Kovar is provided on the upper surface of the side wall 38. Further, as shown in FIG. 10, a stepped portion 40 is provided on the inner bottom surface of the case 30, and the vibrator 21 shown in FIG. The electrode 41 is provided, and the third wiring electrode 41 is electrically connected to the vibrator 21 via the wire line 34. Reference numeral 42 denotes a metal lid. The lid 42 seals the opening of the case 30 so that the inside of the case 30 is in a vacuum atmosphere. Reference numeral 43 denotes a storage portion made of resin, and the storage portion 43 is configured to have a direction perpendicular to a counterpart substrate (not shown) that is an object to be measured for angular velocity, with an angular velocity detection axis as a direction. . The housing portion 43 accommodates the case 30 and the other end of at least three terminals 44 electrically connected to the vibrator 21 at one end. Reference numeral 45 denotes a mounting portion that is positioned substantially in the center of the storage portion 43 and is provided substantially parallel to the angular velocity detection axis of the storage portion 43 and on which the case 30 is mounted. One end side of the terminal 44 is embedded, and the tip end portion 44 a on one end side of the terminal 44 is exposed from the mounting portion 45.

  Further, by placing the case 30 on the placement portion 45 in the storage portion 43, the case electrode 37 in the case 30 is electrically connected to the tip end portion 44 a on one end side of the terminal 44 in the placement portion 45. Since the tip 44a on one end side of the terminal 44 is also mechanically connected to the case 30, the case 30 is supported from the periphery by a terminal 44 in which the other end is integrally embedded in the storage portion 43. It is what.

  Further, as shown in FIG. 10, six electrode recesses 46 are provided on the outer bottom surface of the storage portion 43, and the other end of the terminal 44 embedded in the storage portion 43 in the electrode recess 46. The power supply electrode 47, the GND electrode 48, the output electrode 49, and the three fixing electrodes 50 are provided by exposing the tip portion on the side. Further, as shown in FIG. 9, the six terminals 44 are each provided with a Z-shaped bent portion 44b substantially at the center, and the bent portion 44b further extends the Y-axis extending portion 51 and the Z-axis extending portion. By providing the protruding portion 52, the case 30 is configured to be displaced in the X-axis direction with respect to the storage portion 43. Further, as shown in FIG. 10, three concave portions 53 are provided on the outer bottom surface of the storage portion 43. As shown in FIG. 10, the cover 54 is provided with three locking claws 56 on the opening side as shown in FIG. 10, and the locking claws 56 are provided in the recesses 53 in the storage portion 43 shown in FIG. By fixing by caulking, as shown in FIG. 10, the GND potential connection portion 55 is provided on the outer bottom surface of the storage portion 43.

  Next, the operation of the angular velocity sensor according to the embodiment of the present invention configured as described above will be described.

  When the vibrator 21 is bent at the natural frequency, and the vibrator 21 rotates at an angular velocity ω around the central axis (detection axis) in the longitudinal direction, the Coriolis of F = 2 mV × ω is applied to the arm of the vibrator 21. Force is generated. Due to this Coriolis force, an output signal composed of electric charges is input to the IC 35 via the wire line 34, the third wiring electrode 41, the multilayer circuit board 31, the first wiring electrode 32 and the wire line 34, and waveform processing is performed. After that, the second wiring electrode 33, the capacitor 36, the case electrode 37, and the terminal 44 on one end side 44a, the terminal 44, and the output electrode 49 are input to the other computer (not shown). Thus, the angular velocity is detected.

  Here, considering the case where vibration in the X-axis direction is applied from the outside, in the conventional angular velocity sensor, the terminal 44 is provided with the Y-axis direction extending portion 51 and the Z-axis direction extending portion 52, and thus the case 30. Is bent in the X-axis direction with respect to the storage portion 43, and the external disturbance vibration in the X-axis direction is attenuated so as not to be transmitted to the case 30.

  As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.

International Publication No. 03/046479

  However, in the above-described conventional configuration, the case 30 bends in the X-axis direction with respect to the storage portion 43, so that disturbances in the X-axis direction applied from the outside can be attenuated so as not to be transmitted to the case 30, There has been a problem that vibrations in the Y-axis direction and Z-axis direction applied from the outside cannot be attenuated.

  The present invention solves the above-described conventional problems, and can attenuate all the vibrations in the three axial directions without being able to attenuate the vibrations in the Y-axis direction and the Z-axis direction applied from the outside. An object of the present invention is to provide an angular velocity sensor.

  In order to achieve the above object, the present invention has the following configuration.

  According to a first aspect of the present invention, there is provided a tuning fork type vibrator provided with a drive electrode, a detection electrode and a support portion, an IC for processing an output signal output from the detection electrode in the vibrator, and the vibration A mounting member that supports a support portion in the child, the vibrator, IC, and mounting member are housed inside, a terminal electrode is provided on the stepped portion, and a power supply electrode, a GND electrode, and an output electrode are provided on the outer bottom surface And a case provided with a wiring pattern for electrically connecting the terminal electrode and the power supply electrode, the GND electrode and the output electrode, and the mounting member from the periphery by the terminal electrically connected to the terminal electrode. The terminal is provided with an X-axis direction extending portion, a Y-axis direction extending portion, and a Z-axis direction extending portion. According to this configuration, the terminal extends in the X-axis direction. Part, Y-axis direction extension Since the X-axis direction extension portion and the Y-axis direction extension portion attenuate the vibration in the Z-axis direction applied from the outside, the Y-axis direction extension portion and the Z-axis direction The X-axis direction vibration applied from the outside is attenuated by the extension part, and further, the Y-axis direction vibration applied from the outside is attenuated by the Z-axis direction extension part and the X-axis direction extension part. It has the effect of being able to attenuate vibrations in all directions.

  The invention described in claim 2 of the present invention is such that the terminal connected to the terminal electrode in the case is embedded in the case, and according to this configuration, the terminal connected to the terminal electrode in the case is formed in the case. Since it is embedded, the connection between the terminal electrode and the terminal is strengthened, so that even if strong vibration is applied to the angular velocity sensor, the electrical connection between the terminal electrode and the terminal can be secured. It is what has.

  In the invention according to claim 3 of the present invention, in particular, a plurality of terminals are provided, and the Z-axis direction extending portions of the plurality of terminals are extended in opposite directions to each other, whereby the centers of gravity of the plurality of terminals are obtained. And the center of gravity of the mounting member substantially coincide with each other. According to this configuration, the plurality of terminals are provided, and the X-axis direction extending portions of the plurality of terminals extend in the opposite directions to each other. By doing so, the center of gravity of the plurality of terminals and the center of gravity of the mounting member are substantially coincided with each other, so that when the angular velocity is applied in the Y-axis direction and the Z-axis direction, The vibrator does not move in the front direction or the back direction, and the signal generated from the vibrator is stabilized.

  An angular velocity sensor according to the present invention includes a tuning fork type vibrator provided with a drive electrode, a detection electrode, and a support portion, an IC that processes an output signal output from the detection electrode in the vibrator, and a support portion in the vibrator. The supporting member, the vibrator, the IC, and the mounting member are accommodated inside, the terminal electrode is provided at the step portion, the power supply electrode, the GND electrode, and the output electrode are provided on the outer bottom surface, and the terminal electrode is further provided. And a case provided with a wiring pattern for electrically connecting the power supply electrode, the GND electrode, and the output electrode, and configured so that the mounting member is supported from the periphery by a terminal electrically connected to the terminal electrode In addition, the terminal is provided with an X-axis direction extending portion, a Y-axis direction extending portion, and a Z-axis direction extending portion. According to this configuration, the terminal is provided with an X-axis direction extending portion and a Y-axis direction. Extension and Since the Z-axis extending portion is provided, the X-axis extending portion and the Y-axis extending portion attenuate the vibration in the Z-axis direction applied from the outside, and the Y-axis extending portion and the Z-axis extending portion. The X-axis direction vibration applied from the outside is attenuated by the part, and the Y-axis direction vibration applied from the outside is attenuated by the Z-axis direction extension part and the X-axis direction extension part. It is possible to provide an angular velocity sensor for attenuating vibrations.

1 is an exploded perspective view of an angular velocity sensor according to an embodiment of the present invention. Top view showing the same angular velocity sensor with the top cover removed Bottom view of the same angular velocity sensor Perspective view of transducer in same angular velocity sensor Cross-sectional side view of transducer in same angular velocity sensor The perspective view which shows the state which fixed the vibrator | oscillator and the terminal to the mounting member in the same angular velocity sensor. (A)-(f) Assembling process drawing of vibrator in same angular velocity sensor An exploded perspective view of a conventional angular velocity sensor Top view of the angular velocity sensor The perspective view which looked at the storage part in the same angular velocity sensor from the lower side The perspective view which looked at the case in the same angular velocity sensor from the upper side The perspective view which looked at the case in the same angular velocity sensor from the lower side

  Hereinafter, the invention according to claims 1 to 3 of the present invention will be described using an embodiment.

  1 is an exploded perspective view of an angular velocity sensor according to an embodiment of the present invention, FIG. 2 is a top view showing a state in which the upper lid of the angular velocity sensor is removed, FIG. 3 is a bottom view of the angular velocity sensor, and FIG. FIG. 5 is a side sectional view of the vibrator in the angular velocity sensor, and FIG. 6 is a perspective view showing a state in which the vibrator and the terminal are fixed to a mounting member in the angular velocity sensor.

  1 to 6, reference numeral 61 denotes a tuning fork-shaped vibrator. As shown in FIG. 4, the vibrator 61 includes a first arm portion 61a, a second arm portion 61b, a first arm portion 61a, and a first arm portion 61a. It is comprised by the support part 61c which connects the end of the 2 arm part 61b. As shown in FIG. 5, the vibrator 61 is provided with a common GND electrode 63 made of an alloy thin film of Pt and Ti over the entire upper surface of a base material 62 made of Si, and further, a PZT thin film is formed on the upper surface of the common GND electrode 63. A piezoelectric layer 64 made of is provided. Further, as shown in FIG. 4, the tuning fork-shaped vibrator 61 is located on the inner side of the approximate center of the upper surface, provided with a pair of first drive electrodes 65 on the upper surface of the piezoelectric layer 64, A pair of second drive electrodes 66 are provided on the upper surface of the piezoelectric layer 64 located outside. In addition, the vibrator 61 is provided on the top end side of the upper surface, provided with a pair of detection electrodes 67 on the upper surface of the piezoelectric layer 64, and further on the root side of the first drive electrode 65. A monitor electrode 68 is provided on the upper surface. In addition, a GND electrode 69 is provided on the surface of the piezoelectric layer 64 so as to be positioned on the surface of the support portion 61 c of the vibrator 61.

  Reference numeral 70 denotes a case made of ceramic. The case 70 has a layer structure of ceramic and a conductor for wiring from the inner bottom surface and the inner side surface to the outer bottom surface, and is provided with a multilayer circuit board 72 having a wiring pattern (not shown). The terminal electrode 75 is provided on the stepped portion 74 provided on the inner side surface of the side wall 73 of the case 70, and the power source electrode 76, the GND electrode 77, and the output electrode 78 are provided on the outer bottom surface. The power supply electrode 76, the GND electrode 77, and the output electrode 78 are electrically connected by a wiring pattern (not shown). In addition, a metal frame 79 made of Kovar is provided on the upper surface of the side wall 73 of the case 70. Reference numeral 80 denotes a resin mounting member. The mounting member 80 supports the support portion 61 c of the vibrator 61 and includes eight terminals 81 electrically connected at one end to the terminal electrode 75 of the case 70. Supported from the surroundings. Each of the terminals 81 includes a Y-axis direction extending portion 82, a Z-axis direction extending portion 83, and an X-axis direction extending portion 84, and 4 of the eight terminals 81 are arranged outside. The X-axis direction extending portions 84 of the two terminals 81 extend in the front direction, while the X-axis direction extending portions 84 of the four terminals 81 arranged on the inner side extend in the reverse direction. That is, the center of gravity of the mounting member 80 and the center of gravity of the eight terminals 81 are configured to substantially coincide with each other.

  That is, by extending the X-axis direction extending portions of the eight terminals 81 in opposite directions, the center of gravity of the plurality of terminals 81 and the center of gravity of the mounting member 80 are substantially coincided with each other. When the angular velocity is applied in the Y-axis direction and the Z-axis direction, the vibrator 61 does not move upward or downward due to the movement of the center of gravity of the plurality of terminals, and the signal generated from the vibrator 61 is stabilized. It has the effect of.

  In addition, the first drive electrode 65, the second drive electrode 66, the detection electrode 67, and the GND electrode 69 in the vibrator 61 are electrically connected to the terminal 81 by a wire wire 85. Reference numeral 86 denotes a resin reinforcing member. The reinforcing member 86 is provided so as to cover a connection portion between the terminal 81 and the terminal electrode 75 in the case 70, thereby embedding the terminal 81 in the case 70.

  And since the terminal 81 connected to the terminal electrode 75 in the case 70 is embedded in the case 70, the connection between the terminal electrode 75 and the terminal 81 becomes strong, and even if strong vibration is applied to the angular velocity sensor, This has an operational effect that electrical connection between the terminal electrode 75 and the terminal 81 can be ensured.

  Reference numeral 87 denotes an acceleration sensor element. The acceleration sensor element 87 is provided on the inner bottom surface of the case 70 and is electrically connected to the terminal electrode 75 and a wire wire 85. Reference numeral 88 denotes an IC. The IC 88 is arranged in parallel with the acceleration sensor element 87 on the inner bottom surface of the case 70 and processes an output signal from the vibrator 61 and an output signal from the acceleration sensor element 87. Reference numeral 89 denotes an upper lid made of Kovar, and the upper lid 89 closes the opening of the case 70.

  Next, a method for assembling the angular velocity sensor according to the embodiment of the present invention configured as described above will be described.

  First, as shown in FIG. 7B, a common GND electrode 63 made of an alloy thin film of Pt and Ti is formed by vapor deposition on the upper surface of the base material 62 made of Si shown in FIG. As shown in FIG. 7C, a piezoelectric layer 64 made of a PZT thin film is formed on the upper surface of the common GND electrode 63 by vapor deposition.

  Next, as shown in FIG. 7D, a forming electrode 65a made of an alloy thin film of Ti and Au is formed on the upper surface of the piezoelectric layer 64 by vapor deposition, and then, as shown in FIG. The unnecessary portions of the common GND electrode 63, the piezoelectric layer 64, and the forming electrode 65a are removed so that the first driving electrode 65, the second driving electrode 66, and the detection electrode are formed on the upper surface of the piezoelectric layer 64. 67, a monitor electrode 68 and a GND electrode 69 are formed.

  Next, a voltage is applied to the common GND electrode 63 side, and the first drive electrode 65, the second drive electrode 66, the detection electrode 67, the monitor electrode 68, and the GND electrode 69 are grounded, whereby the piezoelectric layer 64 is formed. Polarize.

  Next, by removing unnecessary portions in the base material 62, the individual vibrators 61 are formed as shown in FIG.

  Next, after the side wall 73 and the stepped portion 74 made of ceramic are formed over the outer periphery of the upper surface of the multilayer circuit board 72 made of an insulator (not shown) made of ceramic and a conductor for wiring (not shown) prepared in advance. A terminal electrode 75 made of Au is formed on the upper surface of the stepped portion 74, and a metal frame 79 made of Kovar is fixed to the upper surface of the side wall 73.

  Next, a power electrode 76 made of Ag, a GND electrode 77 and an output electrode 78 are formed on the lower surface of the multilayer circuit board 72.

  Next, the IC 88 is mounted on the upper surface of the multilayer circuit board 72 in the case 70, and then the IC 88 and the multilayer circuit board 72 are electrically connected.

  Next, after mounting the acceleration sensor element 87 on the upper surface of the multilayer circuit board 72 in the case 70 so as to be juxtaposed with the IC 88, the acceleration sensor element 87 and the terminal electrode 75 in the case 70 are wire wires made of aluminum. An electrical connection is made by wire bonding through 85.

  Next, after insert-molding the eight terminals 81 into the mounting member 80 in advance, the lower surface of the support portion 61 c of the vibrator 61 is fixed to the mounting member 80, and then the first formed on the upper surface of the vibrator 61. The first drive electrode 65, the second drive electrode 66, the detection electrode 67, the monitor electrode 68, the GND electrode 69 and the terminal 81 are electrically connected to each other by wire bonding via a wire wire 85 made of aluminum.

  Next, after the eight terminals 81 are soldered to the terminal electrodes 75 in the case 70, the terminals 81 are embedded in the case 70 by covering with the resin reinforcing members 86.

  Next, a metal upper lid 89 is fixed to the opening of the case 70 in a nitrogen atmosphere by seam welding.

  Next, the operation of the angular velocity sensor according to the embodiment of the present invention configured as described above will be described.

  First, a positive voltage is applied to the first arm 61a and the first drive electrode 65 provided on the first arm 61a of the tuning fork type vibrator 61, and a negative voltage is applied to the second drive electrode 66. Then, the piezoelectric layer 64 positioned below the first drive electrode 65 expands and the piezoelectric layer 64 positioned below the second drive electrode 66 contracts, so that the first arm portion 61a of the vibrator 61 is compressed. And the 2nd arm part 61b is opened toward the outer side.

  Next, a negative voltage is applied to the first arm 61a and the first drive electrode 65 provided on the first arm 61a in the tuning fork vibrator 61, and a positive voltage is applied to the second drive electrode 66. When applied, the piezoelectric layer 64 positioned below the first drive electrode 65 contracts and the piezoelectric layer 64 positioned below the second drive electrode 66 expands. 61a and the second arm part 61b are closed inward. That is, when an AC voltage is applied to the first drive electrode 65 and the second drive electrode 66 in the tuning fork type vibrator 61, the first arm portion 61a and the second arm portion 61b in the vibrator 61 are in the in-plane direction. Bend at a natural frequency of V. The bending motion of the vibrator 61 is controlled by adjusting the voltages applied to the first drive electrode 65 and the second drive electrode 66 so that the output signal generated from the monitor electrode 68 is constant. The amplitude is controlled.

  In addition, in the state where the first arm portion 61a and the second arm portion 61b of the vibrator 61 are bendingly moved at the natural frequency, the vibrator 61 has an angular velocity ω around the longitudinal center axis (detection axis). , A Coriolis force of F = 2 mV × ω is generated in the arms of the first arm portion 61 a and the second arm portion 61 b of the vibrator 61. Due to this Coriolis force, an output signal composed of electric charges generated in the piezoelectric layer 64 positioned below the detection electrode 67 is transmitted through the detection electrode 67, the wire wire 85, the terminal electrode 75, and a wiring pattern (not shown) in the case 70. After being input to the IC 88 and subjected to waveform processing, it is output as an angular velocity output signal from the output electrode 78 in the case 70 to the outside.

  Here, consider a case where a disturbance vibration of about 25 kHz is applied in the Z-axis direction from the outside.

  The X axis direction extending portion 84 and the Y axis direction extending portion 82 are damped to the terminal 81 from outside in the Z axis direction.

  Similarly, when a disturbance vibration of about 25 kHz is applied in the X-axis direction from the outside, the X-axis direction vibration applied from the outside is attenuated by the Y-axis extending portion 82 and the Z-axis extending portion 83. It is something to be made.

Furthermore, when a disturbance vibration of about 25 kHz is applied in the Y-axis direction from the outside,
The Z-axis direction extending portion 83 and the X-axis direction extending portion 84 can attenuate the vibration in the Y-axis direction applied from the outside.

  That is, in the angular velocity sensor according to the embodiment of the present invention, the terminal 81 is provided with the X-axis direction extending portion 84, the Y-axis direction extending portion 82, and the Z-axis direction extending portion 83. The X-axis direction vibration applied from the outside by the Y-axis direction extension part 82 and the Z-axis direction extension part 83 is also attenuated while the part 84 and the Y-axis direction extension part 82 attenuate the vibration in the Z-axis direction. Furthermore, the vibration in the Y-axis direction applied from the outside is attenuated by the Z-axis direction extending portion 83 and the X-axis direction extending portion 84, and all the vibrations in the three axis directions can be attenuated. It has a working effect.

  The angular velocity sensor according to the present invention provides an angular velocity sensor capable of attenuating all the vibrations in the three axial directions without being able to attenuate the vibrations in the Y-axis direction and the Z-axis direction applied from the outside. In particular, it is useful as an angular velocity sensor used in attitude control of a moving body such as an aircraft or a vehicle, a navigation system, or the like.

61 vibrator 61c support part 64 piezoelectric layer 65, 66 drive electrode 67 detection electrode 70 case 74 stepped part 75 terminal electrode 76 power supply electrode 77 GND electrode 78 output electrode 80 mounting member 81 terminal 82 Y-axis direction extension part 83 Z-axis Direction extension part 84 X axis direction extension part

Claims (3)

A tuning fork type vibrator provided with a drive electrode, a detection electrode and a support portion, an IC for processing an output signal output from the detection electrode in the vibrator, a mounting member for supporting the support portion in the vibrator, The vibrator, IC and mounting member are housed inside, a terminal electrode is provided at the stepped portion, and a power supply electrode, a GND electrode and an output electrode are provided on the outer bottom surface, and the terminal electrode, the power supply electrode, the GND electrode, And a case provided with a wiring pattern that electrically connects the output electrode, and the mounting member is configured to be supported from the periphery by a terminal that is electrically connected to the terminal electrode. An angular velocity sensor provided with an axial extension, a Y-axis extension, and a Z-axis extension. The angular velocity sensor according to claim 1, wherein a terminal connected to a terminal electrode in the case is embedded in the case. By providing a plurality of terminals and extending the X-axis direction extending portions of the plurality of terminals in opposite directions, the center of gravity of the plurality of terminals and the center of gravity of the mounting member are substantially aligned with each other. The angular velocity sensor according to claim 1 configured.

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