JP5294089B2 - Piezoelectric device - Google Patents

Description

  The present invention relates to a piezoelectric device, for example, a vibration-resistant structure that stores and holds (supports) a sensor device such as a piezoelectric vibration device, and more particularly, a vibration-resistant structure that stores and holds a yaw rate sensor that detects an angular velocity of an object. Etc.

  Conventionally, a piezoelectric vibration device including a piezoelectric element has been used for the purpose of detecting minute vibrations. As such a piezoelectric vibration device, various devices such as an ultrasonic sensor, a pressure sensor, and a yaw rate sensor (angular velocity sensor) exist. Among these, for example, a yaw rate sensor detects the angular velocity of an object, and detects very weak vibration and displacement generated due to Coriolis force generated when rotation is applied to a vibrating mass body. By detecting through the piezoelectric element, rotation (operation) in each direction can be detected and measured.

  Such piezoelectric vibration devices such as a yaw rate sensor have recently been reduced in size and thickness, and those using a piezoelectric thin film obtained by thin film processing or thin film formation have been proposed or already put into practical use. However, such a small and thin piezoelectric vibration device is generally susceptible to vibrations and impacts from the outside of the equipment or system in which the piezoelectric vibration device is mounted because the piezoelectric thin film itself is extremely thin and lightweight. In some cases, the angular velocity tends to be erroneously detected due to noise caused by the noise.

  In order to prevent such inconvenience, Patent Document 1 discloses that the vibration resistance and shock resistance performance of the yaw rate sensor is improved by using a lead frame that functions as a spring as a fixing portion that supports the piezoelectric vibration element of the yaw rate sensor. Examples of attempts are described.

JP 2005-10034

  FIG. 8 is a cross-sectional view (XZ plane) showing an aspect in which the yaw rate sensor element 320 is supported using the lead frame 330 in the yaw rate sensor 300 described in Patent Document 1. The yaw rate sensor 300 described in Patent Document 1 has a rising portion 330 ′ in which the lead frame 330 rises obliquely from the peripheral edge of the support substrate 310 toward the upper center, and four lead frames are used. The yaw rate sensor element 320 is supported from above in the center of the substrate from four directions (symmetric to the X-axis direction and symmetrical to the Y-axis direction). Here, the lengths of the four lead frames 330a, 330b, 330c, and 330d (only the lead frames 330a and 330b are shown) supporting the yaw rate sensor element 320 are all the same.

  In addition, the yaw rate sensor 300 described in Patent Document 1 needs to be attached with the support substrate 310, the lead frame 330, and the yaw rate sensor element 320 being fixed with a molding resin. Since it is extremely high, its production is not easy and is disadvantageous from the viewpoint of improving productivity. In addition, if the lead frame mounting accuracy is not sufficiently high, it is difficult to securely hold and fix the vibration node (vibration stationary point) of the vibration arm for detection. It will inevitably occur. Further, when absorbing external vibration at the installation position of the yaw rate sensor 300, if the vibration in the XY plane direction is applied even slightly, the rising portions 330a ′ and 330b ′ are displaced (rotational motion) as indicated by the arrow M. As a result, noise in the rotational direction is added to the yaw rate sensor element 320. Such noise in the rotational direction is extremely inconvenient for the yaw rate sensor that detects the rotation of the mass body.

  By the way, in recent years, yaw rate sensors have been widely installed in small electronic devices such as car navigation systems, digital (video) cameras, game machine controllers, mobile phones, and the like. The further downsizing of this is eagerly desired. As described above, when the yaw rate sensor itself (sensor element) is further reduced in size, the amplitude of the detection vibration is further reduced, and as a result, the detection signal is naturally further reduced, so that it is applied to the yaw rate sensor. The influence of noise due to external vibration becomes relatively large, and it may be difficult to obtain a desired sufficient sensitivity required for the yaw rate sensor. In this respect as well, there is an urgent need to further improve the vibration and shock resistance performance of the yaw rate sensor. In addition to these piezoelectric vibration devices, for example, optical sensors used in environmental measurement, information communication, medical fields, and the like have been further reduced in size so that the optical path to be detected is within a normal range. In order to improve the maintenance detection sensitivity, it is required to further improve the vibration resistance and shock resistance performance.

  Therefore, the present invention has been made in view of the above circumstances, and its purpose is to provide a vibration-proof structure for a piezoelectric device that has superior vibration-proof and anti-shock performance against disturbance vibration as compared with the prior art, particularly for unnecessary rotational motion. An object of the present invention is to provide a seismic structure for a piezoelectric device that can effectively prevent noise caused by the noise.

  In order to solve the above-described problems, a piezoelectric device according to the present invention includes a sensor holding body including a sensor unit having a piezoelectric element, and a predetermined direction of the sensor holding body arranged in proximity to at least a part of the outer periphery of the sensor holding body. And a restraining body that suppresses the displacement.

  According to this configuration, when the sensor unit of the piezoelectric device detects minute vibrations, even if an external impact or vibration is applied to the sensor holder in the vibration direction of the sensor unit, Since the suppressors are disposed in close proximity to at least a part of these, the suppressors and the sensor holding body collide with each other. This effectively suppresses, absorbs, reduces, cancels, etc. the displacement of the sensor holder in a predetermined direction (however, the action is not limited to these), thereby suppressing or preventing transmission / propagation of external vibration to the sensor unit. Thus, the detection accuracy of minute vibrations in the sensor unit can be improved. Furthermore, since the transmission of external vibration to the sensor unit is suppressed or prevented, the strain energy of the sensor unit can be reduced to reduce the so-called “temperature drift effect”, thereby stabilizing the operation of the piezoelectric vibration device. It is also possible to increase the nature.

  Specifically, a configuration in which the suppressing body has a surface facing at least a part of the outer periphery of the sensor holding body can be exemplified, and in this case, the movement of the sensor holding body is easily restricted by the “surface” of the suppressing body.

  Moreover, the structure where the width | variety of the gap between a sensor holding body and a suppression body is smaller than half of the thickness of a sensor holding body is mentioned. In such a configuration, for example, when an impact or vibration in a direction other than the direction in which the sensor holding body holds (supports) the sensor (that is, the direction perpendicular to the extending direction of the sensor holding body) is applied, The amount of displacement of the sensor holder in a predetermined direction can be further reduced, and transmission / propagation of external vibration to the sensor unit can be more effectively suppressed or prevented.

  Moreover, you may provide a low-friction film | membrane in at least one part of the outer periphery of a sensor holding body, and the surface which both sides of a suppressing body oppose. In such a configuration, even when the sensor holding body is displaced to the maximum in a predetermined direction and a part of the outer periphery hits the opposing surface of the suppressing body, the impact at the time of the shock is reduced. This suppresses the transmission / propagation of external vibrations to the sensor unit, and further allows the sensor holder to slide in the holding (supporting) direction of the sensor unit in an abutting state. It is possible to prevent the disturbance noise and mechanical stress from being applied more preferentially, and to significantly improve the sensitivity of the sensor unit.

  Furthermore, the sensor holding body and the suppression body are provided with a case accommodated therein, the sensor holding body is supported by the internal space of the case, and the space above and below the sensor holding body is provided in the case. It is preferable to communicate with each other through a vent hole. In such a configuration, the upper space and the lower space of the sensor holding body are not independent from each other, so that gas (air or the like) in both spaces is easily exchanged through the vent hole. As a result, the internal pressure difference between the two spaces is alleviated and the sensor holding body is more easily displaced more smoothly, so that it is possible to more effectively prevent excessive disturbance noise from being applied to the sensor unit. The sensitivity can be further improved.

  Furthermore, you may comprise so that a windbreak wall may be provided near the opening part of the ventilation hole in the space above a sensor holding body. In this way, the gas flow (air, etc.) flowing into the space above the sensor holding body provided with the sensor portion through the vent hole can be blocked by the windbreak wall, so that the gas flow flows into the sensor portion. It is possible to prevent preferentially an increase in noise with respect to the detection operation or the like of the sensor unit due to direct spraying, and the sensitivity of the sensor unit can be further improved.

  Furthermore, the structure which is a housing | casing in which a sensor holding body stores a piezoelectric element is mentioned. Even in such a configuration, the suppression body that suppresses the displacement of the sensor holding body in a predetermined direction is disposed on at least a part of the outer periphery of the sensor holding body (housing) including the sensor unit having the piezoelectric element. Even if an external impact or vibration is applied to the housing that is the sensor holding body, the displacement of the housing in a predetermined direction is effectively suppressed, absorbed, and reduced by the impact of the housing and the restraining body. Can be offset. Therefore, transmission / propagation of external vibrations to the sensor unit housed in the housing as the sensor holding body is suppressed or prevented, and detection accuracy of minute vibrations in the sensor unit can be improved. In addition, since transmission of external vibration to the sensor unit is suppressed or prevented, the strain energy of the sensor unit can be reduced to reduce the so-called “temperature drift effect” or the like.

  According to the piezoelectric vibration device of the present invention, since the suppression body is disposed close to the outer periphery of the sensor holding body, when the sensor unit detects a minute vibration, an external impact or vibration in the detection vibration direction of the sensor unit. Even if applied to the sensor holder, the displacement in a predetermined direction including the rotational movement of the sensor holder can be effectively suppressed, absorbed, reduced, offset, and the like. Furthermore, if there is a low friction film on at least a part of the outer periphery of the sensor holder and / or the opposing surface of the suppressor, extra disturbance noise is applied to the sensor unit. This can be prevented more preferentially and the sensitivity of the sensor unit can be further improved.

It is sectional drawing which shows the internal vibration proof structure of the yaw rate sensor apparatus which concerns on 1st Embodiment. It is an expanded sectional view which shows the proximity | contact state of the balancer side surface and case inner wall surface which concern on 1st Embodiment. It is sectional drawing which shows the internal vibration proof structure of the yaw rate sensor apparatus which concerns on 2nd Embodiment. It is sectional drawing which shows the internal vibration proof structure of the yaw rate sensor apparatus which concerns on 3rd Embodiment. It is sectional drawing which shows the internal vibration proof structure of the yaw rate sensor apparatus which concerns on 4th Embodiment. It is sectional drawing which shows the internal vibration proof structure of the yaw rate sensor apparatus which concerns on 5th Embodiment. It is sectional drawing which shows the external vibration proof structure of the yaw rate sensor apparatus which concerns on 6th Embodiment. It is sectional drawing which shows the structure of the yaw rate sensor element of a conventional system.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the illustrated ratios. Further, the following embodiments are exemplifications for explaining the present invention, and are not intended to limit the present invention only to the embodiments. Furthermore, the present invention can be variously modified without departing from the gist thereof.

<First Embodiment>
FIG. 1 is a cross-sectional view in the XZ direction showing an internal vibration-proof structure of a yaw rate sensor device 1 according to a first embodiment of a piezoelectric device according to the present invention. In this yaw rate sensor device 1 (that is, a piezoelectric vibration device), for example, a depression 11 (a suppressor) provided with a step (in a step shape) inside a case 4 having a box shape, a frame shape, or the like. ), 12 are formed, and these depressions 11, 12 correspond to the internal spaces G1, G2, respectively.

  Of these depressions 11 and 12, an inner space G1 of the deeper depression 11 is a space defined by the inner wall surface 13 and the bottom surface 14 of the case 4, and the bottom surface 14 has a drive vibration of the yaw rate sensor element 2. An integrated circuit element (not shown) such as an IC chip (die) that transmits a drive signal for controlling the control signal and receives a detection signal of a detected vibration detected by the yaw rate sensor element 2 is disposed. A balancer support portion 3 made of a vibration-resistant material is disposed at the center portion of the bottom surface 14, and a balancer 5 (sensor holding body) holding the yaw rate sensor element 2 on the top surface 19 is moved downward in the internal space G1. I support more.

  As the vibration-resistant material of the balancer support portion 3, any solid material having a certain elasticity such as a spring, rubber, gel, or the like may be used depending on the type of sensor to be supported and the installation environment of the yaw rate sensor device 1. it can. In the present embodiment, the balancer support portion 3 is disposed only at the center portion of the bottom surface 14 and supports (holds) the center portion of the balancer 5 to be supported from below at one axis (one place). Is also very simple. However, a plurality of vibration-resistant materials may be disposed on the bottom surface 14, and the center portion of the balancer 5 to be supported may be supported (held) at a plurality of locations from below.

  The balancer 5 extends in the XY plane direction (a direction parallel to the extending direction of the bottom surface 14 of the case 4) and has a thickness t in the Z-axis direction (a direction parallel to the rising direction of the inner wall surface 13). A single plate-like member made of stainless steel or silicon. The outer shape of the balancer 5 in the XY plane direction is substantially the same as the outer shape of the bottom surface 14 of the recess 11, but is actually slightly smaller. In the present embodiment, the shape of the case 4 of the yaw rate sensor device 1 is substantially a rectangular parallelepiped, and the external space in the XY plane direction of the internal space G1 defined inside the case 4 is rectangular, so that the XY of the balancer 5 is The external shape in the planar direction is a rectangle whose long side and short side are slightly shorter than those of the external shape in the XY plane direction of the internal space G1. In the present embodiment, the ± X direction on the paper is the long side direction of the balancer 5, and the ± Y direction is the short side direction of the balancer 5.

  The balancer 5 holds the yaw rate sensor element 2 via the sensor connection member 7 on the upper surface 19 thereof. In this embodiment, since the tuning fork type yaw rate sensor element 2 is used, the connection position is the end of the balancer 5 and the yaw rate sensor element 2, but other sensors may be used. When an ultrasonic sensor or an optical sensor is used as the element, the connection position may be near the center of the balancer 5.

  The yaw rate sensor element 2 is a line (not shown) drawn to the sensor connecting member 7 through a through hole or a line (not shown) drawn from the terminal provided on the upper surface of the yaw rate sensor element 2 to the internal space G2. ) To form an electrical connection to an integrated circuit element (not shown) arranged inside the case 4 by any method such as wire bonding to the case 4, and the drive signal and the detection signal can be transmitted and received. As the case 4 of the yaw rate sensor device 1, for example, one formed by laminating a plurality of ceramic thin plates is used, and covers the open end of the case 4 in the internal space G <b> 2 when the yaw rate sensor device 1 is in use. Sealed by the lid 6.

  FIG. 2 is an enlarged cross-sectional view showing a proximity state between the side surface 8 extending in the Z-axis direction on the outer periphery of the balancer 5 according to the present embodiment and the inner wall surface 13 of the case 4. As shown in FIG. 2, a constant gap g is provided between the side surface 8 of the balancer 5 and the wall surface 13 of the case 4 in a state in which no external vibration is applied to the yaw rate sensor device 1. There is a gap. The outer shape of the balancer 5 in the XY plane direction described above is substantially the same as the outer shape of the bottom surface 14 of the recess 11 but is slightly smaller because the gap having the gap g exists. .

  When vibration is applied from the outside in the usage state of the yaw rate sensor device 1, if the vibration is only a vibration component in the Z-axis direction, the balancer support part 3 expands and contracts only in the Z-axis direction. Displace only in the axial direction. That is, the side surface 8 of the balancer 5 is displaced while maintaining a constant gap g with respect to the inner wall surface 13, and as a result, the balancer 5 does not hit or contact the case 4, and is thus held by the balancer 5. Disturbance noise other than in the Z-axis direction with respect to the yaw rate sensor element 2 cannot occur.

  When the vibration applied from the outside in the usage state of the yaw rate sensor device 1 includes an XY plane direction component, the balancer support portion 3 has an XY plane direction vibration component (in addition to the Z axis direction vibration component). In addition to the Z-axis direction, the balancer support portion 3 extends and contracts in the XY plane direction. Such displacement displaced from the Z-axis direction causes vibration in the XY plane direction or rotational vibration (seesaw motion) (arrow μ in FIG. 1) to the balancer 5 supported by the balancer support portion 3. It will occur. However, in the yaw rate sensor device 1 according to the present embodiment, even when the vibration in the XY plane and the seesaw motion are caused by disturbance vibration, the balancer 5 is displaced from the Z-axis direction. Since the side surface 8 immediately hits and contacts the adjacent inner wall surface 13, excessive displacement including the XY plane direction component is instantaneously suppressed or restricted, and vibration in the XY plane direction and seesaw motion are significantly suppressed. It is possible to prevent. As a result, the yaw rate sensor device 1 adds vibration resistance only to the vibration detection direction (Z-axis direction) of the yaw rate sensor element 2 held on the balancer 5, and significantly affects the influence of disturbance noise other than the vibration detection direction. Can be prevented.

Here, the gap g between the side surface 8 of the balancer 5 and the inner wall surface 13 of the case 4 does not affect the rotation detection capability of the yaw rate sensor element 2, that is, the inclination angle allowable by the balancer 5 is θ. If the thickness of the balancer 5 in the Z-axis direction is t,
g = t × sin θ
It is prescribed by. Therefore, the size of the gap g between the side surface 8 of the balancer 5 and the inner wall surface 13 of the case 4 varies depending on the type of sensor element mounted on the yaw rate sensor device 1 and the usage environment of the yaw rate sensor device 1. It may be determined according to the value of the allowable inclination θ. In the case of the yaw rate sensor element 2 according to the present embodiment, for the purpose of preventing seesaw motion that adversely affects the detection of rotation, the gap g is set to ½ or less of the thickness t of the balancer 5 in the Z-axis direction. It is preferable to do.

  An arbitrary lubricating film 9 having lubricity such as fluorine coating or DLC coating may be provided on the side surface 8 of the balancer 5. By providing the lubricating film 9 on the side surface 8 of the balancer 5, when disturbance vibration other than the component in the Z-axis direction is applied to the yaw rate sensor device 1, the balancer 5 causes a seesaw motion and the side surface 8 is Even if the inner wall surface 13 is hit or contacted, the frictional force that can be generated at the time of hitting or contacting can be reduced.

  Further, the presence of the lubricating film 9 allows the balancer 5 to be moved in the Z-axis without reducing the displacement force in the Z-axis direction applied to the balancer 5 even if the contact time between the balancer 5 and the case 4 is extremely short. It is possible to move up and down by instantaneously sliding in the direction. As a result, the movement of the balancer 5 in the Z-axis direction becomes smoother, so that a good damping performance in the Z-axis direction is imparted when the yaw rate sensor device 1 is used, and the yaw rate sensor element 2 held on the balancer 5 The vibration resistance in the vibration detection direction (Z-axis direction) can be further improved.

  Further, the lubricating film 10 may be provided on the inner wall surface 13 of the case 4. The lubricant film 10 provided on the inner wall surface 13 may be any lubricant having lubricity, such as a fluorine coating or a DLC coating, like the lubricant film 9 on the side surface 8 of the balancer 5, and the lubricant film 9 in the balancer 5. Similarly to the above, not only the impact at the time of collision of the balancer 5 is mitigated, but also the effect of smoothing the movement of the balancer 5 in the Z-axis direction is obtained. Further, it is possible to provide the lubricating films 9 and 10 on both the side surface 8 and the inner wall surface 13, and in this way, the impact mitigation ability and the sliding ability of the balancer 5 will leap when the yaw rate sensor device 1 is used. It is possible to more effectively prevent undesirable disturbance noise from being applied to the yaw rate sensor element 2, and to significantly improve the sensitivity of the yaw rate sensor device 1.

Second Embodiment
FIG. 3 is a cross-sectional view in the XZ direction showing the internal vibration-proof structure of the yaw rate sensor device 20 according to the second embodiment of the piezoelectric vibration device of the present invention. The yaw rate sensor device 20 does not have the stepped depressions 11 and 12 in the first embodiment inside the case 24, and the wall body 21 (suppression body) surrounds the balancer 5. The yaw rate sensor device 1 is configured in the same manner as described above. Therefore, in FIG. 3, members common to the yaw rate sensor element 1 are denoted by the same reference numerals, and description thereof is omitted here in order to avoid redundant description.

  In the present embodiment, the case 24 has a simple container shape having a single recess 22 and having an open upper end, and an inner wall surface 33 and a bottom surface 34 of the case 24 define an internal space G3. Yes. A balancer support portion 3 made of a vibration-resistant material, which may be any solid material having a certain elasticity, such as a spring, rubber, gel, or the like is disposed at the center of the bottom surface 34 of the recess 22, and the yaw rate sensor element 2. Is supported on the upper surface 19 in the internal space G3 of the case 24 from below.

  The balancer 5 according to the present embodiment has its outer shape in the XY plane direction determined according to various conditions such as the type of sensor element to be held, and the outer peripheral side surface of the balancer 5 as in the first embodiment. 28 is not arranged close to the inner wall surface 33 of the case 24. However, the periphery of the side surface 28 of the balancer 5 according to the present embodiment is surrounded by the wall body 21 that rises vertically (in the Z-axis direction) from the bottom surface 34 of the case 24. As in the first embodiment, in a state where no external vibration is applied to the yaw rate sensor device 20 (initial stage), there is a gap g between the side surface 28 of the balancer 5 and the inner wall surface 35 of the wall body. Therefore, when an arbitrary external vibration is applied to the yaw rate sensor device 20, the vibration of the balancer 5 in the XY plane direction, the seesaw motion, and the like are significantly restricted. In addition, lubricating films 29 and 30 such as fluorine coating and DLC coating similar to those of the first embodiment may be provided on the outer side surface 28 of the balancer 5 and the inner wall surface 35 of the wall body 21. It is also possible to improve the sensitivity of the yaw rate sensor device 20 by improving the impact mitigation ability and the sliding ability in the Z-axis direction.

  The wall body 21 according to this embodiment may be formed integrally with the case 24 by laminating a plurality of ceramic thin plates as in the first embodiment, but is attached to the bottom surface 34 of the case 24 in a later step. It is also possible. Then, after installing an arbitrary sensor element and an arbitrary shape balancer 5 holding the arbitrary sensor element via the balancer support portion 3 in the internal space G3 of the case 24 as a general-purpose sensor housing. Thus, the wall body 21 having an outer shape (slightly larger than the outer shape of the balancer 5) corresponding to the outer shape of the balancer 5 of any shape may be attached so as to have a gap of a constant interval g. If it carries out like this, it will become possible to apply the vibration proof structure concerning this embodiment more versatilely to a wide variety of sensor housings. Further, when a plurality of sensor elements are enclosed in a single sensor housing, the wall body 21 can be selected later by attaching only the sensor elements that are easily affected by disturbance vibration in the XY plane direction. It is also possible to create a composite sensor unit having a vibration-proof capability.

  Further, when the vibration suppression range in the XY plane direction determined according to the outer shape of the balancer 5, the type of sensor to be mounted, the installation environment of the sensor device, etc. may be narrow, the shape surrounding the balancer 5 as a whole It is not necessary to provide the wall body 21 having a shape (according to the outer shape of the balancer 5), and a plurality of auxiliary wall bodies 21 surrounding at least a part of the outer periphery of the balancer 5 can also be used. The yaw rate sensor according to this embodiment It becomes possible to manufacture the apparatus 20 more simply. Further, as compared with the case where the lubricant film 30 is applied to the inner wall surface 35 of the case 24 later, the lubricant film 23 is previously applied to the surface of the inner wall surface 35 of the wall body 21 in the previous step, and then the case 24. The retrofitting of the wall body 21 inside makes it possible to further simplify the manufacture of the yaw rate sensor device 20.

<Third Embodiment>
FIG. 4 is an XZ direction cross-sectional view showing the internal vibration-proof structure of the yaw rate sensor device 40 according to the third embodiment of the piezoelectric vibrating device according to the present invention. The yaw rate sensor device 40 is defined in the case between the lower space GL defined between the lower surface 45 of the balancer 5 and the bottom surface 54 of the case 44, and between the upper surface 46 of the balancer 5 and the lid portion 6 of the case 44. The yaw rate sensor device 1 is configured in the same manner as described above except that it includes a passage 41 that communicates with the upper space GU. Therefore, in FIG. 4, members common to the yaw rate sensor element 1 are denoted by the same reference numerals, and description thereof is omitted here in order to avoid redundant description.

  The case 44 according to the present embodiment passes through the inside of the case 44 (bypasses) from the vent hole 42 provided at an arbitrary position on the bottom surface 54 of the case 44 in the lower space GL, and opens in the upper space GU. There is a ventilation passage 41 extending to a ventilation hole 43 provided at a position close to. In the present embodiment shown in FIG. 4, only a single passage 41 is shown. For example, an additional passage (not shown) for ventilation is provided in a space on the opposite side across the balancer support portion 3. Alternatively, a plurality of ventilation passages (not shown) may be provided in the long side direction and / or the short side direction of the case 44. The passage 41 can be formed by laminating a plurality of ceramic thin plates when the case 30 is manufactured.

  Between the side surface 8 of the balancer 5 and the inner wall surface 53 of the case 44, there is a gap g that extends around the balancer 5 as described in the first embodiment. Therefore, for example, even when the balancer 5 is tilted to the maximum extent, there is always a gap in a part of the periphery thereof (for example, the pair of long sides of the side surfaces 8 of the balancer 5 are tilted to the maximum to Even in a state of being in close contact with the inner wall surface 53 of the case 44, the pair of short sides cannot be in close contact with the case 44), and the air between the upper space GU and the lower space GL of the balancer 5 A small amount of movement is possible. However, when the balancer 5 is inclined in this manner, the gap on the side of the balancer 5 becomes narrow, and the movement of air between the upper space GU and the lower space GL is significantly restricted. Alternatively, the air existing in the lower space GL acts like an air cushion against the displacement of the balancer 5 in the Z-axis direction, and further gives unnecessary vibration to the balancer 5, so that the yaw rate sensor device 40 according to the present embodiment. There is also a possibility of adversely affecting the vibration mitigation ability.

  However, in the yaw rate sensor device 40 according to the present embodiment having the passage 41 that communicates the upper space GU and the lower space GL, the balancer support unit 3 contracts due to external vibration applied, and the balancer 5 moves downward. Even in the case of displacement, the air present in the lower space GL flows into the passage 41 through the vent hole 42 and is exhausted to the upper space GU through the vent hole 43. Similarly, when the balancer 5 is displaced upward, the air present in the upper space GU flows into the passage 41 through the vent hole 43, and the air is discharged to the lower space GL through the vent hole 42. . As described above, the air between the upper space GU and the lower space GL of the balancer 5 through the passage 41 can be exchanged (moved) with each other, so that the internal pressure difference between the two spaces is reduced and the balancer 5 Therefore, the vibration of the yaw rate sensor device 40 can be maintained more satisfactorily without giving unnecessary vibration to the balancer 5.

<Fourth embodiment>
FIG. 5 is a cross-sectional view in the XZ direction showing the internal vibration-proof structure of the yaw rate sensor device 40 ′ according to the fourth embodiment of the piezoelectric vibration device of the present invention. The yaw rate sensor device 40 ′ includes mesh members 58 and 59 in the open portions of the vent holes 42 and 43 of the passage 41 that allows the upper space GU and the lower space GL to communicate with each other. Except for the provision of the windbreak wall 57, the configuration is the same as the yaw rate sensor device 40 according to the third embodiment described above. Therefore, in FIG. 5, members common to the yaw rate sensor element 40 are denoted by the same reference numerals, and description thereof is omitted here in order to avoid redundant description.

  Mesh members 58 and 59 provided in each vent hole of the passage 41 in the yaw rate sensor device 40 ′ shown in FIG. 5 suppress the flow of air through the passage 41 between the upper space GU and the lower space GL. In this way, the flow rate / velocity of the positive air flow that occurs when the balancer 5 moves up and down due to disturbance vibration is adjusted. Therefore, even if the sensor element held by the balancer 5 does not like high-speed or significant displacement vibration in the Z-axis direction, the sensor element passes through the passage 41 only by adding the mesh members 58 and 59 to the vent holes of the passage 41. The air flow can be adjusted to further improve the sensitivity of the yaw rate sensor device 40 '. As the mesh members 58 and 59 used in the present embodiment, a porous material having a preferable rectifying ability may be selected as appropriate according to the type of sensor element used, the installation environment of the sensor device, and the like.

  Further, the windbreak wall 57 installed in the vicinity of the ventilation hole 43 in the upper space GU is provided in the upper space GU of the case 44 in the vicinity of the yaw rate sensor element 2 and the ventilation hole 43, and the upper end portion of the windbreak wall 57. And a gap 6 having a distance d through which air passes is provided between the lid portion 6 of the case 44. The windbreak wall 57 may be formed integrally with the case 44 or may be retrofitted to the case 44.

  In the present embodiment, a windbreak wall 57 is provided between the ventilation hole 43 and the yaw rate sensor element 2, and when the balancer 5 is displaced downward, the positive airflow discharged from the ventilation hole 43 is generated on the windbreak wall 57. By passing only the gap of the distance d through which air passes between the upper end portion and the lid portion 6 of the case 44, the discharged air flow directly strikes the yaw rate sensor element 2 and the drive vibration of the yaw rate sensor element 2 It is possible to significantly prevent noise from detecting vibration and to improve the sensitivity of the yaw rate sensor device 40 '.

<Fifth Embodiment>
FIG. 6 is a cross-sectional view in the XZ direction showing the internal vibration-proof structure of the yaw rate sensor device 60 according to the fifth embodiment of the piezoelectric vibration device of the present invention. The yaw rate sensor device 60 is configured in the same manner as the yaw rate sensor device 1 described above except that it has a balancer wall 66 rising at the peripheral edge of the balancer 65. Therefore, in FIG. 6, members common to the yaw rate sensor device 1 are denoted by the same reference numerals, and description thereof is omitted here in order to avoid redundant description.

  The balancer 65 in this embodiment is made of stainless steel, silicon, or the like, and has a thickness t in the Z-axis direction while extending in the XY plane direction, but only the edge portion is directed upward in the Z-axis direction. The balancer wall 66 stood up. In other words, the balancer 65 has a container shape having a recess and an open end. Further, the outer surface 67 of the balancer wall 66 has a gap with a constant interval between it and the inner wall surface 13 of the case 4.

  Since the balancer 65 according to the present embodiment has a large surface area of the outer surface 67 of the balancer wall 66, when the balancer 65 is displaced in the Z-axis direction due to disturbance vibration, a seesaw motion occurs in the XY plane direction. Even in this case, the displacement in the XY plane direction between the outer surface 67 and the wall surface 13 of the case 4 can be more effectively regulated and suppressed. Further, if lubricant films 69 and 70 such as fluorine coating and DLC coating similar to those of the first embodiment are provided on both or one of the outer surface 67 of the balancer wall 66 and the inner wall surface 13 of the case, the impact of the balancer 65 is reduced. It is possible to further improve the sensitivity of the yaw rate sensor device 60 by further improving the capability and the sliding capability.

  Further, the balancer 65 according to the present embodiment is such that when the external vibration is applied and the balancer support portion 3 contracts and the balancer 65 is displaced downward, the air present in the lower space GL is exposed to the outer surface of the balancer wall 66. Even when moving to the upper space GU of the balancer 65 through the gap between the case 67 and the inner wall surface 13 of the case, the rising height of the balancer wall 66 is much higher than the mounting position of the yaw rate sensor element 2. Therefore, it is possible to significantly prevent the air flow from directly hitting the yaw rate sensor element 2 and causing noise to the drive vibration and the detection vibration of the yaw rate sensor element 2, and the sensitivity of the yaw rate sensor device 60. Can be further improved.

<Sixth Embodiment>
FIG. 7 is a cross-sectional view in the XZ direction showing the external vibration-proof structure of the yaw rate sensor device according to the sixth embodiment of the piezoelectric vibration device of the present invention. In the present embodiment, a sensor package 100 in which at least one yaw rate sensor element 2 is enclosed is supported from below by a support portion 103 provided on the installation surface of the sensor package 100. As the support portion 103, any solid member having a certain elasticity, such as a spring, rubber, or gel, can be used. A plurality of support portions 103 may be arranged, and the sensor package 100 to be supported may be supported (held) at a plurality of locations from below.

  On the side of the sensor package 100, there is provided a vibration-resistant frame 101 that stands up on the installation surface of the sensor package 100, and an outer peripheral surface 104 of the sensor package 100 and an inner wall surface 105 of the vibration-resistant frame 101. The sensor package is surrounded by a gap with a certain interval. Further, both the outer peripheral surface 104 of the sensor package 100 and the inner wall surface 105 of the vibration-resistant frame 101 are provided with lubricating films 109 and 110 that may be any lubricant having lubricity, such as fluorine coating or DLC coating. ing.

  The sensor package 100 according to the present embodiment is provided with a vibration-resistant frame 101 on the side as in the above-described embodiment, so that vibration in a direction parallel to the installation surface, rotational vibration, that is, seesaw motion (see FIG. 7 can be prevented, and the influence of disturbance noise on the gyro sensor element 2 and the like in the package can be significantly prevented. In the sensor package 100 according to the present embodiment, the lubricant films 109 and 110 are provided on the outer peripheral surface 104 of the sensor package 100 and the inner wall surface 105 of the vibration-resistant frame 101, so that disturbance vibrations other than in the Z-axis direction can be detected. It is possible to ensure the impact mitigation ability and the sliding ability even when applied to the sensor package, and more effectively prevent excessive disturbance noise from being applied to the sensor package 100. The sensitivity of the gyro sensor element 2 can be significantly improved.

  The present invention is not limited to each of the above-described embodiments. As described above, various modifications (for example, appropriate contents of each embodiment are possible without departing from the spirit of the present invention). Combination) is possible. For example, a through-hole that communicates with the upper space GU and the lower space GL is additionally provided at a position that is a part of the balancers 5 and 65 and does not adversely affect the mounted sensor elements due to airflow, It is also possible to form the outer shape itself so as to have a hole portion, and the sensitivity of the yaw rate sensor device can be improved by making the displacement of the balancers 5 and 65 in the Z-axis direction smoother. Further, the wall body 21 and the vibration-resistant frame 101 that support the balancers 5 and 65 or the sensor package 100 from the side are surrounded if they are partially surrounded rather than completely surrounded by the side. It is also possible to create escape of air that escapes to the side rather than the part that is not present, and in this case also, the displacement in the Z-axis direction of the balancer 5, 65 or the sensor package 100 becomes smoother, so unnecessary vibrations can be generated. It does not occur and the sensitivity of the yaw rate sensor device can be improved.

  1, 20, 40, 40 ', 60 ... yaw rate sensor device (piezoelectric vibration device), 2 ... yaw rate sensor element (piezoelectric vibration device), 3 ... balancer support, 4, 24 ... case, 5, 65 ... balancer, 6 ... lid part, 7 ... sensor connecting member, 8, 28 ... side face, 9, 10, 29, 30, 69, 70, 109, 110 ... lubricating film, 11, 12, 22 ... depression, 13, 33, 35, 53 ... inner wall surface, 14, 34 ... bottom surface, 19, 46 ... upper surface, 21 ... wall body, 42, 43 ... vent, 45 ... lower surface, 57 ... windbreak wall, 58, 59 ... mesh member, 66 ... balancer wall, 67 DESCRIPTION OF SYMBOLS ... Outer surface, 100 ... Sensor package, 101 ... Vibration-resistant frame, 103 ... Support part, 104 ... Outer peripheral surface, 105 ... Inner wall surface, 300 ... Yaw rate sensor, 320 ... Yaw rate sensor element, 330 ... Reed frame Over arm, G1, G2 ... internal space, GU ... upper space, GL ... lower space, M, mu ... Rotation

Claims (2)

A sensor holder that supports a sensor unit having a piezoelectric element;
A suppressor that is disposed in the vicinity of at least a portion of the outer periphery of the sensor holder and suppresses displacement of the sensor holder in a predetermined direction;
A case in which the sensor holding body and the suppressing body are housed, and
The sensor holder is supported in the internal space of the case;
The piezoelectric device , wherein a space above the sensor holding body and a space below the sensor holding body communicate with each other through a vent hole provided in the case . A windbreak wall is provided near the opening of the vent hole in the space above the sensor holder,
The piezoelectric device according to claim 1.

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