JP2015001493A - Physical quantity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a physical quantity sensor capable of outputting signals with improved accuracy, which is free from fluctuation of the output signals even when an impact load is applied to the physical quantity sensor.SOLUTION: Compared to a conventional manner in which undesired vibration is attenuated by an anti-vibration member only, the physical quantity sensor is arranged to improve the anti-vibration effect by attenuating undesired vibration of a detection element by means of a terminal 73 and an anti-vibration member 71.

Description

  In particular, the present invention relates to a physical quantity sensor that detects, for example, an angular velocity that has excellent impact resistance.

  A conventional angular velocity sensor of this type is configured as shown in FIG.

  FIG. 17 is a perspective view of a conventional angular velocity sensor.

  In FIG. 17, reference numeral 1 denotes an angular velocity detecting element. This angular velocity detecting element 1 is provided with four vibrating portions 2 erected in the Z direction, and a piezoelectric element 3 is provided on the outer surface of the vibrating portion 2, and further, The connection part 4 which connects the lower part of the part 2 integrally is provided. Reference numeral 5 denotes a weight portion, and the weight portion 5 is fixed to the lower surface of the connection portion 4 in the angular velocity detecting element 1. Reference numeral 6 denotes a metal vibration-proof member. The metal vibration-proof member 6 is fixed to the lower surface of the weight portion 5 and has a trapezoidal hole 7 extending from the upper side to the lower side. Or the support part 8 extended toward the Y-axis direction is provided. Further, a fixing portion 9 is provided on the outer peripheral side of the metallic vibration-proof member 6, and the outer peripheral side of the support portion 8 is connected and fixed by the fixing portion 9. Reference numeral 10 denotes a case. The case 10 fixes the lower surface of the fixing portion 9 of the metal vibration isolating member 6 to the upper surface, and is provided with a rectangular parallelepiped hole 11 located below the angular velocity detecting element 1. ing. Reference numeral 12 denotes a vibration isolating member made of silicone gel. The vibration isolating member 12 is filled in the hole 11 in the case 10 and further filled in the hole 7 in the metal vibration isolating member 6. The vibration isolating member 12 made of the silicone gel is provided in the Z-axis direction of the angular velocity detecting element 1.

  Next, the operation of the conventional angular velocity sensor configured as described above will be described.

  When an AC voltage is applied to the piezoelectric element 3 in the angular velocity detecting element 1, as shown in FIG. 18, the four vibrating parts 2 in the angular velocity detecting element 1 are driven to vibrate in the diagonal direction of the cross section and in different directions. In this state, when an angular velocity around the Z axis is generated in the angular velocity detecting element 1, a Coriolis force of F = 2 mV × ω is generated in a direction perpendicular to the vibration driving direction as shown in FIG. Vibrate. The angular velocity generated in the angular velocity detecting element 1 can be detected by amplifying the charge generated in the piezoelectric element 3 in the vibration section 2 by this vibration and converting it into a voltage.

  Here, considering the case where an impact load other than the normal angular velocity is applied to the angular velocity sensor from the outside, in the conventional angular velocity sensor, the vibration isolating member 12 made of silicone gel is provided in the angular velocity detecting element 1, so that Due to the viscoelasticity of the vibration member 12, unnecessary vibration caused by the impact load is attenuated.

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

JP 2000-213942 A

  However, in the conventional configuration, since only the vibration isolating member 12 made of silicone gel is provided, for example, as shown in FIG. 20, in the vicinity of 41 kHz that is the frequency of vibration drive of the angular velocity detecting element 1, the gain is Since it is 0.005 and sufficient vibration attenuation has not been achieved, if an impact load is applied to the angular velocity detection element, the vibration drive will be affected, and this causes the output signal to fluctuate. Had.

  The present invention solves the above-mentioned conventional problems, and provides a physical quantity sensor with improved output signal accuracy that does not fluctuate in output signal even when an impact load is applied to the physical quantity sensor. It is intended to do.

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

  According to the first aspect of the present invention, a detection element, a mounting portion on which the detection element is mounted, and the mounting portion and one end are connected and electrically connected to the detection element and the lead wire. A terminal connected to the bottom, a bottomed cylindrical case that houses the detection element and the mounting portion and supports the other end of the terminal, and is positioned between the inner bottom surface of the case and the mounting portion According to this configuration, since the resin vibration isolation member is provided between the inner bottom surface of the case and the placement portion, the terminal and the vibration isolation member are provided. By both, the unnecessary vibration of the detection element will be attenuated, and as a result, the anti-vibration effect by the terminal can be expected as compared with the case where the unnecessary vibration is attenuated only by the anti-vibration member. While electrically connecting the case and the detection element Will be able to prevent the impact load is applied to the detecting element, the output signal is one that has the effect that not fluctuate.

  According to the second aspect of the present invention, the vibration isolating member is provided from the inner bottom surface to the inner side surface of the case. According to this configuration, the vibration isolating member is arranged in the X-axis, Y-axis, and Z-axis of the detection element. Therefore, unnecessary vibration generated in the detection element can be attenuated by any of the X-axis direction, the Y-axis direction, and the Z-axis direction due to the viscoelasticity of the vibration-proof member. Thus, this has the effect of further stabilizing the output signal from the detection element.

  The invention according to claim 3 of the present invention is a resin vibration-proof member made of urethane gel or silicone gel, and according to this configuration, the resin vibration-proof member is made of urethane gel or silicone gel. Therefore, in a liquid state, the vibration isolating member can be cured after filling the case that houses the detection element, thereby having the effect that the vibration isolating member can be easily provided. is there.

  A detecting element; a mounting part for mounting the detecting element; a terminal connected to the mounting part at one end and electrically connected to the detecting element through a lead wire; the detecting element and the mounting element; A bottomed cylindrical case that houses the placement portion and supports the other end of the terminal, and a resin-made vibration-proof member is provided between the inner bottom surface and the placement portion in the case, According to this configuration, since the vibration isolating member made of resin is provided between the inner bottom surface of the case and the mounting portion, unnecessary vibration of the detection element is attenuated by both the terminal and the vibration isolating member. As a result, it is possible to expect an anti-vibration effect by the terminal as compared with the case where the unnecessary vibration is attenuated only by the anti-vibration member, so that the case and the detection element are electrically connected by the terminal. , Impact load is applied to the sensing element Will can be suppressed, as a result, those having the effect that it is possible to provide a physical quantity sensor that does not vary in the output signal.

Side sectional view of physical quantity sensor in one embodiment of the present invention Side sectional view of the detection element in the physical quantity sensor Top view of the detection element in the physical quantity sensor Side sectional view of the location where the piezoelectric element of the detection element in the physical quantity sensor is provided Circuit diagram of the physical quantity sensor Side sectional view showing a state in which the detection element in the physical quantity sensor is driven to vibrate in the Z-axis direction The figure which shows the state which detects the angular velocity around the X-axis of the physical quantity sensor Side sectional view showing a state in which the detection element in the physical quantity sensor operates by Coriolis force in the Y-axis direction Waveform diagram showing the state of synchronous detection of the output signal from the physical quantity sensor at the drive frequency in the Z-axis direction The figure which shows the state which detects the angular velocity around the Y-axis of the physical quantity sensor Waveform diagram showing the state of synchronous detection of the output signal from the physical quantity sensor at the drive frequency in the Z-axis direction The figure which shows the state which detects the angular velocity around the Z-axis of the physical quantity sensor Waveform diagram showing the state of synchronous detection of the output signal from the physical quantity sensor at the drive frequency in the Y-axis direction The figure which shows the damping characteristic of the vibration by the terminal of the physical quantity sensor in one embodiment of this invention The figure which shows the damping characteristic of the vibration by the terminal of the physical quantity sensor in one embodiment of this invention, and a vibration isolator Side sectional view of a physical quantity sensor described in the written description in an embodiment of the present invention A perspective view of a conventional angular velocity sensor The top view which shows the state which the vibration part of the angular velocity detection element in the conventional angular velocity sensor drives by vibration The top view which shows the state which the vibration part of the angular velocity detection element in the conventional angular velocity sensor operate | moves The figure which shows the damping characteristic of the vibration by the vibration isolator of the conventional angular velocity sensor

  Hereinafter, a physical quantity sensor according to an embodiment of the present invention will be described with reference to the drawings.

  1 is a side sectional view of a physical quantity sensor according to an embodiment of the present invention, FIG. 2 is a side sectional view of a detection element in the physical quantity sensor, FIG. 3 is a top view of the detection element, and FIG. 4 is a detection in the physical quantity sensor. FIG. 5 is a circuit diagram of the physical quantity sensor. FIG.

  1 to 5, reference numeral 20 denotes a detection element capable of detecting angular velocities in the triaxial directions of the X axis, the Y axis, and the Z axis, and this detection element is provided with stepped portions 20 a on both sides of the upper surface. A plurality of element electrode pads 20b are provided in the portion 20a. Further, as shown in FIG. 2, the detection element 20 has a mass portion 21 made of Si in the shape of a rectangular parallelepiped. Further, the detection element 20 is provided with a first X-axis direction support member 22 made of Si, and the first X-axis direction support member 22 supports an upper portion of one side surface of the mass portion 21. In addition, an outer driving piezoelectric body 23 made of a pair of PZTs is provided outside the upper surface, and an inner driving piezoelectric body 24 made of a pair of PZTs is further provided inside the upper surface. Further, on the upper surface of the first X-axis direction support member 22, an outer detection piezoelectric body 25 is provided between the pair of outer drive piezoelectric bodies 23, and the pair of inner drive piezoelectric bodies is further provided. The inner detection piezoelectric body 26 is provided between 24. Further, the detection element 20 is provided with a second X-axis direction support member 27 made of Si, and the second X-axis direction support member 27 is supported by the first X-axis direction in the mass portion 21. While supporting the upper part of one side opposite to the side where the member 22 is provided, an outer driving piezoelectric body 28 made of a pair of PZTs is provided outside the upper surface, and an inner driving piezoelectric body made of a pair of PZTs inside the upper surface. 29 is provided. Further, on the upper surface of the second X-axis direction support member 27, an outer detection piezoelectric member 30 is provided between the pair of outer drive piezoelectric members 28, and the pair of inner drive piezoelectric members is further provided. 29, an inner detection piezoelectric body 31 is provided.

  Further, the detection element 20 is provided with a first Y-axis direction support member 32 made of Si, and the first Y-axis direction support member 32 supports an upper portion of one side surface of the mass portion 21. The outer drive piezoelectric body 33 made of a pair of PZT is provided outside the upper surface, and the inner drive piezoelectric body 34 made of a pair of PZT is further provided inside the upper surface. Further, on the upper surface of the first Y-axis direction support member 32, an outer detection piezoelectric member 35 is provided between the pair of outer drive piezoelectric members 33, and further the pair of inner drive piezoelectric members. 34, an inner detection piezoelectric body 36 is provided. Further, on the upper surface of the first Y-axis direction support member 32, an outer monitor piezoelectric body 37 is provided outside the outer drive piezoelectric body 33 and is positioned outside the inner drive piezoelectric body 34. An inner monitor piezoelectric body 38 is provided.

  In addition, the detection element 20 is provided with a second Y-axis direction support member 39 made of Si, and the second Y-axis direction support member 39 is the first Y-axis direction of the mass portion 21. While supporting the upper part of one side opposite to the side where the support member 32 is provided, an outer driving piezoelectric body 40 made of a pair of PZTs is provided outside the upper surface, and an inner driving piezoelectric material made of a pair of PZTs inside the upper surface. A body 41 is provided. Further, on the upper surface of the second Y-axis direction support member 39, an outer detection piezoelectric body 42 is provided between the pair of outer drive piezoelectric bodies 40, and the pair of inner drive piezoelectric bodies is further provided. 41, an inner detection piezoelectric body 43 is provided. Further, on the upper surface of the second Y-axis direction support member 39, a pair of inner monitor piezoelectric bodies 68 are provided outside the pair of inner drive piezoelectric bodies 41.

  Further, as shown in FIG. 4, the outer drive piezoelectric member 23 and the outer detection piezoelectric member 25 located on the upper surface of the first X-axis support member 22 are made of the first X-axis support member 22 made of Si. Provided on the upper surface of the common GND electrode 44 made of an alloy thin film of Pt and Ti provided on the upper surface, and provided with a drive electrode 45 on the upper surface of the outer drive piezoelectric member 23 and a detection electrode on the upper surface of the outer detection piezoelectric member 25. 46 is provided.

  The outer driving piezoelectric members 23, 28, 33, 40, the inner driving piezoelectric members 24, 29, 34, 41, the outer detection piezoelectric members 25, 30, 35, 42, and the inner detection piezoelectric members 26, 31, 36, 43. Is electrically connected to the element electrode pad 20b by a circuit pattern (not shown).

  The mass portion 21 is supported by the first X-axis direction support member 22, the second X-axis direction support member 27, the first Y-axis direction support member 32, and the second Y-axis direction support member 39. By doing so, the drive frequency in the X-axis direction is 39 kHz, the drive frequency in the Y-axis direction is 41 kHz, and the drive frequency in the Z-axis direction is 40 kHz. That is, the driving frequency of the mass portion 21 is set to be different in the X-axis direction, the Y-axis direction, and the Z-axis direction, and the driving frequency in the Z-axis direction is set to a central value.

  Then, the first X-axis direction support member 22, the second X-axis direction support member 27, the first Y-axis direction support member 32, and the second Y-axis direction support member 39 are as shown in FIG. In addition, there are four holes 19 between them, and an outer peripheral portion 69 in which the outer peripheral side is integrally connected is provided.

  Reference numeral 47 denotes a bottomed rectangular cylindrical frame made of Si. The frame 47 includes the first X-axis direction support member 22, the second X-axis direction support member 27, and the first Y-axis direction support member 32. And the outer peripheral part 69 connected with the 2nd Y-axis direction supporting member 39 is supported.

  An IC 48 is provided with a plurality of IC electrode pads 48a on both sides of the lower surface, and the IC electrode pads 48a are electrically connected to the element electrode pads 20b in the detection element 20.

  Further, as shown in FIG. 5, the IC 48 includes a drive circuit 49 and a detection circuit 50, and the drive circuit 49 includes a Z-axis direction drive circuit 51a and a Y-axis direction drive circuit 51b. It is what. Further, the Z-axis direction drive circuit 51a performs differential output signals from the outer monitor piezoelectric body 37 in the first Y-axis direction support member 32 and the inner monitor piezoelectric body 68 in the second Y-axis direction support member 39. Values are input to the outer drive piezoelectric bodies 23, 28, 33, 40 and the inner drive piezoelectric bodies 24, 29, 34, 41 via the IV converter 52, the band pass filter 53 and the AGC circuit 54 in the Z-axis direction drive circuit 51a. Thus, the mass portion 21 is driven to vibrate with a constant amplitude in the Z-axis direction. Similarly, the Y-axis direction drive circuit 51b outputs from the inner monitor piezoelectric body 38 in the first Y-axis direction support member 32 and the inner monitor piezoelectric body 68 in the second Y-axis direction support member 39. By inputting the differential value of the signal to the outer driving piezoelectric bodies 33 and 40 and the inner driving piezoelectric bodies 34 and 41 via the IV converter 55, the band pass filter 56 and the AGC circuit 57 in the Y-axis direction driving circuit 51b, The mass portion 21 in the detection element 20 is driven to vibrate with a constant amplitude in the Y-axis direction.

  The detection circuit 50 includes a Y-direction Coriolis force detection circuit 58 and an X-direction Coriolis force detection circuit 59. The Y-direction Coriolis force detection circuit 58 is outside the first Y-axis direction support member 32. The output signals of the detection piezoelectric member 35 and the inner detection piezoelectric member 36 are input to the IV converter 60, and the output signals of the outer detection piezoelectric member 42 and the inner detection piezoelectric member 43 in the second Y-axis direction support member 39 are IV converted. After the input to the detector 61 and the difference between the two, the synchronous detector 62 detects the angular velocity around the X axis by synchronous detection at the drive frequency in the Z-axis direction. The X-direction Coriolis force detection circuit 59 includes an IV converter 63 for inputting output signals of the outer detection piezoelectric body 25 and the inner detection piezoelectric body 26 in the first X-axis direction support member 22, and a second X-axis. The differential value of the output signal from the IV converter 64 that receives the output signals from the outer detection piezoelectric member 30 and the inner detection piezoelectric member 31 in the direction support member 27 is obtained by the synchronous detector 65 at the drive frequency in the Z-axis direction. By detecting synchronously, the angular velocity around the Y axis is detected. Further, similarly to these, the synchronous detector 66 detects the angular velocity around the Z-axis by performing synchronous detection at the drive frequency in the Y-axis direction.

  Reference numeral 67 denotes a case made of ceramic with a bottomed rectangular tube shape. The case 67 accommodates the detection element 20 inside, and has the IC 48 on the inner bottom surface. The case 67 has a multilayer circuit board (not shown) and is electrically connected to the IC 48 via the IC electrode pad 48a.

  Reference numeral 71 denotes an anti-vibration member made of urethane gel. The anti-vibration member 71 is filled on the upper surface of the IC 48 provided on the inner bottom surface of the case 67.

  Reference numeral 72 denotes a resin mounting portion. The mounting portion 72 mounts the detection element 20 on the upper surface, and is provided on the upper surface of the vibration isolating member 71 provided on the upper surface of the case 67 via the IC 48. Yes.

  Reference numeral 73 denotes a metal terminal. The metal terminal 73 is formed integrally with the mounting portion 72 so that one end is connected to the mounting portion 72 and the detection element 20 and the lead wire 74 are connected to each other. Is electrically connected.

  Reference numeral 75 denotes an upper lid made of ceramic, and the upper lid 75 closes the upper surface opening of the case 67.

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

  First, a common GND electrode 44 made of an alloy thin film of Pt and Ti is formed by vapor deposition on the upper surface of a substrate (not shown) made of Si prepared in advance, and then made of a PZT thin film on the upper surface of the common GND electrode 44. Outside drive piezoelectric bodies 23, 28, 33, 40, inside drive piezoelectric bodies 24, 29, 34, 41, outside detection piezoelectric bodies 25, 30, 35, 42, inside detection piezoelectric bodies 26, 31, 36, 43, outside monitor The piezoelectric body 37 and the inner monitor piezoelectric bodies 38 and 68 are formed by vapor deposition.

  Next, the outer drive piezoelectric bodies 23, 28, 33, 40, the inner drive piezoelectric bodies 24, 29, 34, 41, the outer detection piezoelectric bodies 25, 30, 35, 42, the inner detection piezoelectric bodies 26, 31, 36, 43 The driving electrode 45 made of an alloy thin film of Ti and Au, the detection electrode 46 and the monitor electrode (not shown) are formed on the upper surfaces of the outer monitor piezoelectric member 37 and the inner monitor piezoelectric members 38 and 68.

  Next, while applying a voltage to the common GND electrode 44 side and grounding the drive electrode 45, the detection electrode 46 and the monitor electrode (not shown), the outer drive piezoelectric bodies 23, 28, 33, 40, the inner drive Piezoelectric bodies 24, 29, 34, 41, outer detection piezoelectric bodies 25, 30, 35, 42, inner detection piezoelectric bodies 26, 31, 36, 43, outer monitor piezoelectric bodies 37, and inner monitor piezoelectric bodies 38, 68 are polarized. .

  Next, by removing unnecessary portions in the base material (not shown), the mass portion 21, the first X-axis direction support member 22, the second X-axis direction support member 27, and the first Y-axis direction. The detection element 20 including the support member 32, the second Y-axis direction support member 39, the outer peripheral portion 69, and the frame body 47 is formed.

  Next, the IC 48 is mounted on the inner bottom surface of the case 67, and the IC electrode pad 48 a is electrically connected to a multilayer circuit board (not shown) in the case 67.

  Next, after the terminal 73 is formed integrally with the mounting portion 72, the other end of the terminal 73 is connected to the case 67.

  Next, after the inner bottom surface of the case 67 is filled with a vibration isolating member 71 made of a liquid urethane gel until the upper surface of the IC 48 and the lower surface of the mounting portion 72 are connected, about 1 at about 100 ° C. Curing is performed by heating for a period of time, and the mounting portion 72 and the IC 48 are connected by the vibration isolating member 71.

  That is, since the resin vibration-proof member 71 is made of urethane gel, the vibration-proof member 71 can be cured after being filled in the case 67 in a liquid state. It has the effect that it can be provided.

  Finally, the upper surface opening of the case 67 is closed by the upper lid 75.

  Next, the operation of the physical quantity sensor according to the embodiment of the present invention configured and assembled as described above will be described.

  First, a case where an angular velocity around the X axis is first added to the mass portion 21 will be described.

  First, when a positive voltage is applied to the inner drive piezoelectric bodies 24, 29, 34, and 41 and a negative voltage is applied to the outer drive piezoelectric bodies 23, 28, 33, and 40, as shown in FIG. 24, 29, 34, and 41 are extended, and the outer drive piezoelectric bodies 23, 28, 33, and 40 are contracted. As a result, the mass portion 21 moves upward. Next, when a negative voltage is applied to the inner driving piezoelectric bodies 24, 29, 34, and 41, and a positive voltage is applied to the outer driving piezoelectric bodies 23, 28, 33, and 40, the inner driving piezoelectric bodies 24, 29, 34, and 41 shrinks and the outer driving piezoelectric bodies 23, 28, 33, 40 extend, and as a result, the mass portion 21 moves downward. That is, the mass unit 21 is driven to vibrate at a speed V at a drive frequency in the Z-axis direction. The vibration drive of the mass portion 21 is such that the output signals generated from the outer monitor piezoelectric member 37 and the inner monitor piezoelectric member 68 are constant, and the inner drive piezoelectric members 24, 29, 34, 41 and the outer drive piezoelectric member 23. , 28, 33, and 40 are adjusted to control the amplitude of vibration drive.

  Further, when the mass unit 21 rotates at an angular velocity ω around the central axis in the X-axis direction in a state where the mass unit 21 is driven to vibrate at a drive frequency in the Z-axis direction, as shown in FIG. 21 generates a Coriolis force of F = 2 mV × ω in the Y-axis direction. Due to this Coriolis force, the mass portion 21 is driven to vibrate in the Y-axis direction. Therefore, as shown in FIG. 8, for example, as shown in FIG. A positive charge is generated by the expansion of the piezoelectric body 36, and a negative charge is generated by the contraction of the outer detection piezoelectric element 42 and the inner detection piezoelectric element 43 in the second Y-axis direction support member 39. The electric charges generated from the outer detection piezoelectric member 35 and the inner detection piezoelectric member 36 are converted into output signals by the IV converter 60, and the electric charges generated from the outer detection piezoelectric member 42 and the inner detection piezoelectric member 43 are converted into the IV converter 61. 9 to obtain an output signal, and after taking the difference between the two, as shown in FIG. 9, the synchronous detector 62 performs synchronous detection at the frequency of the vibration drive in the Z-axis direction, thereby changing the angular velocity around the X-axis. It is to detect.

  Next, a case where an angular velocity around the Y axis is added to the mass unit 21 will be described.

  Also in this case, as in the case where the angular velocity around the X axis is detected, the mass portion 21 is angularly rotated around the central axis in the Y axis direction when the mass portion 21 is driven to vibrate in the Z axis direction. As shown in FIG. 10, a Coriolis force of F = 2 mV × ω in the X-axis direction is generated in the mass portion 21 as shown in FIG. Due to the Coriolis force, the mass portion 21 is driven to vibrate in the X-axis direction, so that the outer detection piezoelectric body 25 and the inner detection piezoelectric body 26 in the first X-axis direction support member 22 are extended by the vibration drive, thereby causing positive charge. Is generated, and the outer detection piezoelectric member 30 and the inner detection piezoelectric member 31 of the second X-axis direction support member 27 are contracted to generate a negative charge. The electric charges generated from the outer detection piezoelectric member 25 and the inner detection piezoelectric member 26 are converted into output signals by the IV converter 63, and the electric charges generated from the outer detection piezoelectric member 30 and the inner detection piezoelectric member 31 are converted into the IV converter 64. 11 to obtain an output signal, and after taking the difference between the two, as shown in FIG. 11, the synchronous detector 66 performs synchronous detection at the vibration drive frequency in the Z-axis direction, thereby changing the angular velocity around the Y-axis. It is to detect.

  Next, a case where an angular velocity around the Z axis is added to the mass portion 21 will be described.

  In order to detect the angular velocity around the Z-axis, the mass unit 21 is driven to vibrate in the Y-axis direction as shown in FIG.

  First, a positive voltage is applied to the outer drive piezoelectric body 33 and the inner drive piezoelectric body 34 in the first Y-axis direction support member 32, and at the same time, the outer drive piezoelectric body 40 and the inner drive piezoelectric element in the second Y-axis direction support member 39. When a negative voltage is applied to the body 41, the outer driving piezoelectric member 33 and the inner driving piezoelectric member 34 are extended, and the outer driving piezoelectric member 40 and the inner driving piezoelectric member 41 are contracted. It moves toward the Y-axis direction support member 32.

  Next, a negative voltage is applied to the outer drive piezoelectric body 33 and the inner drive piezoelectric body 34 in the first Y-axis direction support member 32, and at the same time, the outer drive piezoelectric body 40 and the inner drive in the second Y-axis direction support member 39. When a positive voltage is applied to the piezoelectric body 41, the outer driving piezoelectric body 33 and the inner driving piezoelectric body 34 contract, and the outer driving piezoelectric body 40 and the inner driving piezoelectric body 41 extend, and as a result, the mass unit 21 has the second portion. It moves toward the Y-axis direction support member 39. That is, the mass unit 21 is driven to vibrate at a speed V at a drive frequency in the Y-axis direction. The vibration drive of the mass portion 21 is such that the output signals generated from the inner monitor piezoelectric members 38 and 68 are constant, so that the outer drive piezoelectric member 33, the inner drive piezoelectric member 34, the outer drive piezoelectric member 40, and the inner drive piezoelectric member. The amplitude of vibration drive is controlled by adjusting the voltage applied to the body 41.

  When the mass unit 21 is driven to vibrate in the Y-axis direction and the mass unit 21 rotates at an angular velocity ω around the central axis in the Z-axis direction, the mass unit 21 has F = 2 mV × ω in the X-axis direction. Coriolis force is generated. Due to the Coriolis force, the mass portion 21 is driven to vibrate in the X-axis direction, so that the outer detection piezoelectric body 25 and the inner detection piezoelectric body 26 in the first X-axis direction support member 22 are extended by the vibration drive, thereby causing positive charge. Is generated, and the outer detection piezoelectric member 30 and the inner detection piezoelectric member 31 of the second X-axis direction support member 27 are contracted to generate a negative charge. The electric charges generated from the outer detection piezoelectric member 25 and the inner detection piezoelectric member 26 are converted into output signals by the IV converter 63, and the electric charges generated from the outer detection piezoelectric member 30 and the inner detection piezoelectric member 31 are converted into the IV converter 64. The output signal is converted into an output signal, and the difference between the two is obtained. Then, as shown in FIG. 13, the synchronous detection is performed by the synchronous detector 66 at the vibration drive frequency in the Y-axis direction. It is to detect.

  Here, considering the case where an impact load is applied to the physical quantity sensor from the outside, in the physical quantity sensor according to the embodiment of the present invention, the vibration isolating member 71 made of silicone gel is disposed on the lower surface of the detection element 20 and the case 67. As shown in FIG. 20, as described above, unnecessary vibration generated in the detection element 20 due to the viscoelasticity of the vibration isolating member 71 is provided so as to be connected via the IC 48 from the bottom surface. , The gain amount near 41 kHz is attenuated to about 0.005.

  Similarly, the attenuation of the terminal 73 provided between the mounting portion 72 and the case 67 attenuates the gain amount near 41 kHz to about 0.1, as shown in FIG.

  Therefore, as shown in FIG. 15, the gain amount near 41 kHz can be attenuated to about 0.005 by the attenuation effect obtained by superimposing both the vibration isolating member 71 and the terminal 73.

  In the physical quantity sensor according to the embodiment of the present invention, the vibration isolating member 71 is a urethane gel, but a silicone gel has the same effect.

  In the physical quantity sensor according to the embodiment of the present invention, the vibration isolating member 71 is provided on the inner bottom surface of the case 67. However, as shown in FIG. Even if the member 76 is provided, the same effect is obtained.

  Further, in the physical quantity sensor according to the embodiment of the present invention, the vibration isolating member 71 has a shape having a certain volume. However, for example, even if it is thinly provided like an adhesive, the same effect can be obtained.

  Note that, as an example of the physical quantity sensor in one embodiment of the present invention, the physical quantity sensor that detects the angular velocity has been described. However, the physical quantity sensor can also be applied to a physical quantity sensor that detects acceleration and distortion. However, when the angular velocity is detected as in the present embodiment, the drive direction and the detection direction are orthogonal to each other. Therefore, as shown in FIG. With the biaxial vibration-proof structure of the vibration-proof structure (vibration-proof member 71) in the thickness direction, the impact resistance can be greatly improved. Furthermore, by making the attenuation frequency of the vibration isolation structure in the plane direction (terminal 73) different from that of the vibration isolation structure in the thickness direction (vibration isolation member 71), the vibration isolation performance can be improved with respect to both the drive frequency and the detection frequency. Can be improved. Furthermore, in the case of a multi-axis detection element that detects angular velocities around the X-axis, Y-axis, and Z-axis, since it has a plurality of drive frequencies and detection frequencies, it has a further anti-vibration effect.

  The physical quantity sensor according to the present invention has an effect of providing a physical quantity sensor with improved accuracy of the output signal, in which the output signal does not fluctuate even when an impact load is applied. It is useful when applied to a physical quantity sensor with excellent impact resistance that detects angular velocity.

20 Detection element 67 Case 71, 76 Anti-vibration member 72 Placement part 73 Terminal 74 Lead wire

Claims (3)

A detecting element; a mounting part for mounting the detecting element; a terminal connected to the mounting part at one end and electrically connected to the detecting element through a lead wire; the detecting element and the mounting element; A physical quantity sensor that houses a mounting portion and supports a bottomed cylindrical case that supports the other end of the terminal, and a resin vibration-proof member positioned between an inner bottom surface of the case and the mounting portion. The physical quantity sensor according to claim 1, wherein the vibration isolating member is provided from the inner bottom surface to the inner side surface of the case. The physical quantity sensor according to claim 1, wherein the resin vibration-proof member is urethane gel or silicone gel.

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