JP2014190718A - Angular velocity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an angular velocity sensor that allows an addition of a simple structure to attain suppression of an unnecessary oscillation from an angular velocity sensor element, or suppression of a transmission of an unnecessary oscillation from an outside to the angular velocity sensor element.SOLUTION: The angular velocity sensor element comprises: a piezoelectric oscillation type angular velocity sensor element 3; a package 2 that anchors the angular velocity sensor element 3; and a lid part 4 that encapsulates the package 2. The lid part 4 is formed into an anti-oscillation structure part 6 of a two-layer structure of a lid part 5 and at least a set of a low rigidity part 7 and a high rigidity part 8, and thereby an oscillation from an outside becomes harder to be transmitted to the angular velocity sensor element 3, and an unnecessary oscillation can be suppressed. Further, an unnecessary oscillation to be generated from the angular velocity sensor element 3 can be suppressed from leaking to the outside through other components.

Description

  The present invention relates to a piezoelectric vibration type angular velocity sensor, and more particularly to a vibration resistant structure of the sensor.

  In recent years, many devices that detect minute vibrations using piezoelectric elements have been utilized. As one of them, for example, by detecting very weak vibrations and displacements caused by Coriolis force generated when rotation is applied to a vibrating mass body through a piezoelectric element, rotational movement in each direction That is, a piezoelectric vibration type angular velocity sensor capable of detecting and measuring a rotational angular velocity, that is, a so-called gyro sensor is known.

  Among them, as a long-life, low-cost, small and lightweight piezoelectric vibration type angular velocity sensor, it is provided with a sensor element having a plurality of vibration arms facing each other across the base, and one vibration arm, that is, the drive arm is in a plane. There has been proposed or put to practical use an H-type angular velocity sensor that is driven and detects vibration and displacement generated in the direction orthogonal to the driving direction by the Coriolis force by the other vibrating arm, that is, the detection arm. However, in order to realize an extremely small and highly sensitive angular velocity sensor, it is necessary to obtain a large displacement using the resonance frequency of each vibrating arm.

  For example, an angular velocity sensor used in an automobile requires high performance in terms of vibration resistance and shock resistance. The angular velocity sensor element vibrates in a complicated manner by at least two orthogonal vibration modes of an excitation vibration for obtaining a Coriolis force and a detection vibration for detecting the Coriolis force. It is desirable that the vibrations of these angular velocity sensor elements are originally vibrated in a closed system.

  However, in an actual angular velocity sensor element, the vibration of the sensor element may leak out of the element through other components depending on the unwanted vibration caused by processing asymmetry and the mode shape of the vibration mode used for excitation and detection. Unavoidable. For this reason, when the angular velocity sensor is mounted, the vibration state changes, so the characteristics of the vibrator change. On the other hand, there is an effect that the angular velocity sensor element is excited by external vibration. In this case, for example, the angular velocity sensor element is excited by vibration while the vehicle is running, and the signal output of the angular velocity sensor may fluctuate, causing the system to malfunction.

  In order to reduce such unnecessary vibration from the angular velocity sensor element, that is, vibration leakage and the influence of external vibration on the angular velocity sensor element, the following structure is provided between the angular velocity sensor element and the package or mounting portion. The providing technique is disclosed. Patent Document 1 includes a large internal package that encloses a sensor element between a sensor element base portion and a mounting portion, that is, an external resin case, and a plurality of lead terminals that connect the internal package and the external resin case, A technique is disclosed in which a frame body for aligning lead terminals at a predetermined interval is provided.

  Japanese Patent Laid-Open No. 2004-260688 discloses a protection portion configured by supporting a base portion of an angular velocity sensor element on the surface between the angular velocity sensor element base portion and the mounting portion and having an area equivalent to the package area, and silicon rubber. A technique provided with a vibrator is disclosed.

JP 2010-185811 A JP 2008-8634 A

  As disclosed in the prior art document, the angular velocity sensor element makes an erroneous detection due to unnecessary external vibration, or makes an erroneous detection by an unnecessary vibration caused by the angular velocity sensor element itself. Therefore, there is a problem that correct detection cannot be performed. Also, as disclosed in the prior art document, the method of improving by processing or providing a new frame or vibration isolator made of silicon rubber requires a complicated holding structure because it is made by combining a plurality of members. As the number of assembly steps increases, assembly accuracy and cost increase become problems.

  The present invention has been made in view of the above problems, and realizes suppression of unnecessary vibration from the angular velocity sensor element and suppression of transmission of unnecessary vibration from the outside to the angular velocity sensor element by adding a simple structure. An object is to provide a possible angular velocity sensor.

  The present invention includes a piezoelectric vibration type angular velocity sensor element, a package for fixing the angular velocity sensor element, a lid portion for sealing the package, and the lid portion includes a lid for directly sealing the package; The vibration-resistant structure portion is laminated on a lid, and the vibration-resistant structure portion is made of a low-rigidity portion made of a material having a lower rigidity than the lid portion and a material having a rigidity higher than or equal to the lid portion. The angular velocity sensor has a two-layer structure of at least one pair of high-rigidity portions, and the low-rigidity portions are arranged between the lid and the high-rigidity portions.

  By adopting such a configuration, when a low-rigidity part and a high-rigidity part are laminated in this order on the lid to form a two-layer structure, external vibrations are less likely to be transmitted to the element, and unnecessary vibrations are suppressed. It has an excellent effect of being able to. Moreover, it has the outstanding effect that it can suppress that the unnecessary vibration generate | occur | produced from an angular velocity sensor element leaks outside through other components.

  Moreover, the effect which suppresses an unnecessary vibration can be raised by specifying each material of a lid, a low-rigidity part, and a high-rigidity part, and also optimizing a Young's modulus and each layer thickness.

  According to the present invention, it is possible to provide an angular velocity sensor capable of suppressing unnecessary vibration from the angular velocity sensor element and suppressing transmission of unnecessary vibration from the outside to the angular velocity sensor element by adding a simple structure. it can.

FIG. 3 is an exploded perspective view of the angular velocity sensor according to the first embodiment. 2 is a perspective view of an angular velocity sensor according to Embodiment 1. FIG. 2 is a cross-sectional view of an angular velocity sensor according to Embodiment 1. FIG. It is a top view which shows the mode of the vibration of a comparative example. It is the image figure which looked at the mode of vibration of a comparative example in the section. It is the image figure which looked at the mode of vibration of Embodiment 1 in the section. It is the image figure seen in the cross section in order to demonstrate a shear stress. It is sectional drawing of the angular velocity sensor in Embodiment 2. FIG. It is a figure which shows the evaluation result in Example 1. FIG. It is a figure which shows the evaluation result in Example 1. FIG. It is a figure which shows the evaluation result in Example 1. FIG. It is a figure which shows the evaluation result in Example 2. FIG.

  Although the form for implementing this invention is demonstrated in detail, referring drawings, this invention is not limited by the content described in the following embodiment. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the constituent elements described below can be appropriately combined. In addition, various omissions, substitutions, or changes of components can be made without departing from the scope of the present invention.

(Embodiment 1)
FIG. 1 is an exploded perspective view showing the overall configuration of the angular velocity sensor 1 of the first embodiment. In FIG. 1, an angular velocity sensor 1 according to Embodiment 1 includes a package 2 that is fixed to an object to be detected such as a vehicle, an angular velocity sensor element 3, and a lid 4 that seals the package 2. FIG. 2 is a perspective view of the angular velocity sensor 1 shown in FIG. 1, but the lid 4 is omitted.

  3 is a cross-sectional view taken along line AA in FIG. In FIG. 3, the angular velocity sensor element 3 is fixed to the package 2 by a fixing portion 14, and a lid portion 4 that seals the package 2 includes a lid 5 that directly seals the package 2, and a resistance to resistance laminated on the lid 5. The vibration structure unit 6 is used. Further, the vibration-resistant structure portion 6 has a two-layer structure of at least one pair of a low rigidity portion 7 and a high rigidity portion 8. The vibration-resistant structure 6 is configured with a smaller area than the lid 5 so as not to be caught when the lid 5 is directly sealed in the package 2.

  Next, a structure in which unnecessary vibration from the outside according to the first embodiment is not transmitted to the angular velocity sensor element 3 by the vibration-resistant structure unit 6 will be described. If the vibration-resistant structure portion 6 of the first embodiment is not provided, unnecessary vibrations such as vibrations caused by running a vehicle are directly transmitted to the angular velocity sensor element 3, and the signal output of the angular velocity sensor 1 fluctuates. The system will malfunction. By providing the vibration-resistant structure portion 6 having the two-layer structure of at least one pair of the low-rigidity portion 7 and the high-rigidity portion 8 according to the first embodiment, unnecessary vibration from the outside is suppressed.

  In addition, regarding the unnecessary vibration from the angular velocity sensor element 3 according to the first embodiment, the structure that does not transmit the unnecessary vibration to the outside by the vibration resistant structure section 6 is processed from the angular velocity sensor element 3 if the vibration resistant structure section 6 is not provided. Unnecessary vibration caused by the asymmetry of the leakage leaks to the outside of the element through other components. As a result, the signal output of the angular velocity sensor 1 fluctuates and the system malfunctions. By providing the vibration-resistant structure portion 6 having at least one pair of the low-rigidity portion 7 and the high-rigidity portion 8, unnecessary vibration from the angular velocity sensor element 3 is suppressed.

  The technical principle that the vibration-resistant structural part 6 is excellent in at least one set of two-layer structure in which the low-rigidity part 7 and the high-rigidity part 8 are laminated on the lid 5 in this order will be described. The lid 5 is made of a material such as Kovar (FeNiCo alloy) or stainless steel (FeCrNi alloy) and is susceptible to vibration. However, there is a situation that this material must be used in consideration of the sealing property of the package. The low rigidity portion 7 is a material having a lower rigidity than the lid 5 and is made of a resin material such as silicon rubber or fluorine resin. The high-rigidity portion 8 is a material having high rigidity equal to or higher than that of the lid 5 and is made of a material such as Kovar or stainless steel. Simply laminating a low-rigidity material and a high-rigidity material does not solve the problem, but the relationship between the rigidity of the low-rigidity material and the high-rigidity material is important. The thickness ratio of the low rigidity portion 7 and the high rigidity portion 8 is also greatly affected.

  The relationship between the rigidity of the low-rigidity portion 7 and the high-rigidity portion 8 is as follows. For the Young's modulus, which is a measure of rigidity, the numerical value of the ratio is rigid in order to obtain the effect that external vibrations are not easily transmitted to the element. It is preferable that the numerical value of the Young's modulus ratio, that is, the ratio of Young's modulus with low rigidity / Young's modulus with high rigidity is 0.50 or less.

  Furthermore, in order to obtain an effect that external vibrations are not easily transmitted to the element, the ratio of the low rigidity Young's modulus / high rigidity Young's modulus of the rigidity of the low rigidity portion 7 and the high rigidity portion 8 is 0. When the thickness ratio is 50 or less, in order to obtain an effect that each layer thickness ratio is less likely to transmit vibration from the outside to the element, the layer thickness ratio of the low rigidity portion / the layer thickness ratio of the high rigidity portion is 0.2 or more, Preferably it is 0.2-5.0.

  The stacking order is preferably stacked on the lid 5 in the order of the low rigidity portion 7 and the high rigidity portion 8. The reason for this is that the low-rigidity portion 7 that is easily deformed is sandwiched between the lid 5 and the high-rigidity portion 8 that have higher Young's modulus and higher rigidity than the low-rigidity portion. Unnecessary vibration applied from the outside due to the shear stress generated at both the joint surfaces of the rigid portion 7 and the high-rigidity portion 8 is attenuated by the vibration-resistant structure portion 6 and further from the outside. This is because a high effect is obtained that makes it difficult to be transmitted to the element.

(Embodiment 2)
7 is a cross-sectional view taken along line AA shown as Embodiment 2 in FIG. 2 shown as Embodiment 1. FIG. In the second embodiment, unlike the first embodiment, as shown in FIG. 7, the vibration-resistant structure portion 6 is disposed below the lid 5, that is, inside the space sealed by the package 2 and the lid 5. Yes. By providing the anti-vibration structure 6 at the lower part of the lid 5, it is possible to prevent unwanted vibration from the angular velocity sensor element 3 and unnecessary vibration from outside without increasing the overall size of the angular velocity sensor in the layer thickness direction. As in the first embodiment, it can be effectively suppressed. However, also in the second embodiment, the basic conditions described in the first embodiment, that is, the relationship between the rigidity of the low-rigidity material and the high-rigidity material, each layer thickness ratio, and the stacking order must be satisfied.

  As Example 1, a sample having the configuration of Embodiment 1 was prepared. In the comparison between Example 1 and the comparative example described below when unnecessary vibration is applied from the outside in the Z-axis direction, that is, the vertical direction, the state of vibration of the lid portion 4 will be described.

  As a comparative example, a sample of the lid 4 in a state in which no countermeasure is taken as in the first embodiment, that is, a sample having the lid 4 constituted only by the lid 5 was prepared. FIG. 4A is a diagram showing a state of vibration of the lid portion 4 when the unnecessary vibration is applied from the outside in the Z-axis direction, that is, when the laminated plane is viewed from above. FIG. 4B is an image diagram showing the state of vibration when the state of FIG. 4A is viewed in the Y-axis direction, that is, the section taken along the XZ plane of the BB section.

  According to the comparative example, when unnecessary vibration is applied from the outside in the Z-axis direction, unnecessary vibration in the Z-axis direction is transmitted to the lid 4, that is, the lid 5 through the package 2. As a result, as shown in FIGS. 4a and 4b, the vibration 9 generated from the unnecessary vibration in the Z-axis direction extends from the central portion of the lid portion 4 directly fixing the package 2 and the lid 5 to the entire plane of the lid portion 4. Occur. The vibration 9 causes the mounted circuit board 13 to vibrate excessively, and the angular velocity sensor element 3 vibrates and adversely affects the output signal.

  On the other hand, FIG. 5 shows the cover 4 when the unnecessary vibration is applied from the outside in the Z-axis direction, that is, the vertical direction, using the cover 4 having the configuration of the first embodiment. It is the image figure which showed the mode of the vibration 9, and is the figure which showed the mode of the vibration seen in the Y-axis direction, ie, a cross section when cut by XZ plane like FIG. 4b.

  According to the first embodiment, similarly to the comparative example, when unnecessary vibration is applied from the outside in the Z-axis direction, the unnecessary vibration in the Z-axis direction is applied to the lid portion 4, that is, the lid 5 and vibration resistance through the package 2. Although transmitted to the structure portion 6, the difference between the first embodiment and the comparative example is offset by the generation of a vibration waveform 10 that cancels the vibration waveform 9 generated in the comparison example, as shown in FIG. As a result, unnecessary vibration is suppressed.

  The vibration waveform 10 of the first embodiment generated so as to cancel the vibration waveform 9 generated in the comparative example is a joint surface between the lid 5 and the low rigidity portion 7 constituting the lid portion 4 of the first embodiment, or the low rigidity portion. The unnecessary vibration applied from the outside is attenuated by the vibration-resistant structural portion 6 due to the shear stress generated between the joint surface of the high-rigidity portion 8 and the high-rigidity portion 8, and as a result, the Z-axis direction is unnecessary from the outside. The angular velocity sensor element 3 is not affected by the vibration. Note that the vibration waveform may have two or more vibration nodes and antinodes, but unnecessary vibration is suppressed by the same principle.

  Shear stress is the stress generated when an object is deformed diagonally. Specifically, this means that a force is always applied perpendicular to the surface in tension and compression, but parallel to the surface. When a force is applied to, it works in the direction of deforming like a parallelogram. The stress generated at this time is called shear stress, and its value is the same as the tensile stress, which is a value obtained by dividing the force applied parallel to the cross-sectional area by the cross-sectional area.

  FIG. 6 is an image diagram showing the state of the shear stress 11 using the lid portion 4 having the configuration of the first embodiment. As shown in FIG. 4B, a cross section taken along the Y-axis direction, that is, the XZ plane. It is the figure seen in. As shown in FIG. 6, the shear stress 11 is the maximum at the midpoint of the width direction in the X-axis direction (L / 2 when the width is L) when both ends of the lid 4 are supported by the support points 12. It occurs to have an amplitude.

  The shear stress 11 generated in the first embodiment has a two-layer structure in which the vibration-resistant structure portion 6 is laminated on the lid 5 in the order of the low-rigidity portion 7 and the high-rigidity portion 8 in the lid portion 4. This occurs so as to cancel out the vibration 9 generated from the unnecessary vibration. By combining the rigid portions having the contradictory properties that the high-rigidity portion 8 is difficult to deform and the low-rigidity portion 7 is easily deformed, the shear stress 11 is further increased, and the configuration of FIG. Referring to FIG. 5 and FIG. 5, for example, when convex in the Z-axis direction, that is, upward, a stress is generated such that the high-rigidity portion 8 is stretched and the low-rigidity portion 7 is compressed. However, it is necessary to satisfy the basic conditions, that is, the relationship between the rigidity of the low-rigidity material and the high-rigidity material that constitutes the vibration-resistant structural portion 6, the layer thickness ratio, and the stacking order.

  By adopting the configuration of the first embodiment, the angular velocity sensor element 3 is mounted on the package 2 without the vibration-resistant structure portion 6, and the angular velocity sensor 1 is directly mounted on the mounting portion. The support intersection of the angular velocity sensor element 3 can be reduced without being affected by the assembly accuracy of the portion 6. Further, the tolerance of the characteristics of the angular velocity sensor 1 can be reduced.

  In the configuration of the first embodiment, the vibration-resistant structure unit 6 can effectively prevent the vibration transmitted from the angular velocity sensor element 3 during the driving vibration from being transmitted to the lid 5 through the package 2. Thus, it is possible to eliminate the need for some anti-vibration measures between the angular velocity sensor element 3 and the package 2 as in the prior art.

  In the configuration of the first embodiment, the vibration-resistant structure unit 6 can effectively prevent external vibration transmitted to the lid 5 through the package 2 with respect to external unnecessary vibration input from the outside of the sensor. In this way, it is possible to eliminate the need for some anti-vibration measures between the angular velocity sensor element 3 and the package 2.

  In the configuration of the first embodiment, the vibration-resistant structure portion 6 is simply bonded to the lid 5, and it is not necessary to change the method for joining the lid 5 to the package 2 or the shape of the lid 5. For this reason, since the lid 5 used for sealing the conventional package 2 can be used as it is, it is possible to provide a vibration-resistant structure that is easy to assemble and inexpensive.

  In the configuration of the first embodiment, the vibration-resistant structure portion 6 can be disposed on almost the entire surface of the lid 5. According to this configuration, since the vibration-resistant structure portion 6 can be arranged in a wide area, it is possible to suppress the vibration from the angular velocity sensor element 3 from leaking to the outside, and the unnecessary vibration from the outside is prevented from entering the angular velocity sensor element 3. It is possible to suppress the transmission.

  In Example 2, five samples of the comparative example and Example 1 were prepared for each of the parameters shown below to give unnecessary vibration from the outside, and the output signal based on the unnecessary vibration at that time was plotted and evaluated. . The output signal is an output signal when the angular velocity sensor element 3 vibrates when the mounted circuit board 13 (FIG. 3) is vibrated due to unnecessary vibration from the outside. Therefore, this output signal is a signal based on the unnecessary signal, and it is indicated that the larger this numerical value, the more the angular velocity sensor element 3 is affected by unnecessary vibration, which is not preferable.

  In the sample actually used in Example 2, the ratio of the Young's modulus of low rigidity / Young's modulus of high rigidity is 0.25, the material of the low rigidity portion 7 is silicon rubber, the Young's modulus is 45 MPa, and the layer thickness is On the other hand, the material of the high-rigidity portion 8 is a stainless alloy having a Young's modulus of 180 MPa and a layer thickness of 0.1 mm.

  FIG. 8 is a graph showing the effect of the relationship between the rigidity of the low-rigidity portion 7 and the high-rigidity portion 8 of the vibration-resistant structure portion 6 in Example 2 on the ratio of Young's modulus, which is a measure of rigidity. It is the figure which plotted the output signal based on the unnecessary vibration from. FIG. 8 shows the ratio of the Young's modulus of low rigidity / high rigidity on the horizontal axis as parameters of comparative examples, 0.5 and 0.25, while each output signal [V] corresponding to the vertical axis. Is plotted. In the comparative example, only the lid 5 is provided, and the vibration-resistant structure portion 6 is not provided.

  According to FIG. 8, as the ratio of Young's modulus of low rigidity / high rigidity becomes smaller, the output signal based on unnecessary vibration becomes smaller, and it becomes difficult for unnecessary vibration from the outside to be transmitted to the angular velocity sensor element 3. It shows that the effect of suppressing the vibration is large. Since it is effective also for the comparative example, it shows that the effect by the vibration-resistant structure part 6 is large. FIG. 8 shows that the ratio of Young's modulus of low rigidity / high rigidity is preferably 0.50 or less. At this time, the material of the low rigidity portion 7 is silicon rubber, the Young's modulus is 45 MPa, and the layer thickness is 0.1 mm. On the other hand, for the high-rigidity portion 8, the material when the ratio of the Young's modulus of low rigidity / high rigidity is 0.5 is Kovar with a Young's modulus of 90 MPa, the layer thickness is 0.1 mm, and the material when the ratio is 0.25 Stainless steel with a Young's modulus of 180 MPa and a layer thickness of 0.1 mm.

  FIG. 9 is a plot of output signals based on unnecessary external vibration against each layer thickness ratio when the ratio of Young's modulus of low rigidity / Young's modulus of high rigidity is 0.50 or less in Example 2. FIG. FIG. 9 shows the layer thickness ratio of the low-rigidity part / high-rigidity part on the horizontal axis, with the comparative examples 0.1, 0.2, 1.0, and 5.0, and the vertical axis. Each output signal corresponding to the axis is plotted. In the comparative example, only the lid 5 is provided, and the vibration-resistant structure portion 6 is not provided.

  According to FIG. 9, when the layer thickness ratio of the low-rigidity part / high-rigidity part is 0.1, the output is almost equivalent to that of the comparative example, but the output signal based on unnecessary vibration increases as the value becomes larger than 0.1. However, it is smaller than that of the comparative example, and it is difficult for unnecessary vibration from the outside to be transmitted to the angular velocity sensor element 3, indicating that the effect of suppressing the vibration to the angular velocity sensor element 3 is great. FIG. 9 shows that the layer thickness ratio of the low rigidity portion / high rigidity portion is 0.2 or more, preferably 0.2 to 5.0. At this time, the material of the low rigidity portion 7 is silicon rubber, the Young's modulus is 45 MPa, and the layer thickness is 0.01 mm, 0.02 mm, 0.1 mm, and 0.5 mm for each parameter. On the other hand, the high-rigidity portion 8 is made of stainless steel with a Young's modulus of 180 MPa and a layer thickness of 0.1 mm.

  FIG. 10 is a diagram in which output signals based on unnecessary external vibrations are plotted for five cases in the stacking order of the low-rigidity portion 7 and the high-rigidity portion 8 of the vibration-resistant structure portion 6 in Example 2. . FIG. 10 shows the configuration of the vibration-resistant structure 6 on the horizontal axis, for example, from the package side, that is, in order from the bottom in the Z-axis direction of FIG. Rigid part 8, configuration C: lid / low rigidity part 7, configuration D: lid / low rigidity part 7 / high rigidity part 8, composition E: lid / high rigidity part 8 / low rigidity part 7 On the other hand, each output signal [V] corresponding to the vertical axis is plotted. In the comparative example, only the lid 5 is provided, and the vibration-resistant structure portion 6 is not provided.

  According to FIG. 10, in the case of the configuration B: lid / high rigidity portion 8, the output is almost the same as that of the configuration A: comparative example, but in the case of configuration C: lid / low rigidity portion 7, there is external vibration. Due to the effect that it is difficult to be transmitted to the element, the output is smaller than that in the case of the configuration B: lid / high-rigidity portion 8, and the effect of suppressing vibration is surely seen. Further, the configuration D: lid / low-rigidity portion 7 / high-rigidity portion 8 has the smallest output and is highly effective, but the configuration E: lid / high-rigidity portion 8 / low-rigidity portion 7 configuration. Then, because of the function of not easily transmitting the vibration of the low-rigidity portion 7, the output was small compared to the comparative example, and the effect of suppressing the vibration could be confirmed. Configuration D: The configuration of the lid / low-rigidity portion 7 / high-rigidity portion 8 is more effective than the configuration of the configuration C: lid / low-rigidity portion 7, Configuration E: lid / high-rigidity portion 8 / low-rigidity portion 7 What is larger is that the vibration from the outside is further increased by the shear stress generated on both the joint surface of the lid 5 and the low-rigidity portion 7 and the joint surface of the low-rigidity portion 7 and the high-rigidity portion 8. This is thought to be because it has the effect of making it difficult to communicate.

  The low-rigidity portion 7 is a material that is less rigid than the lid 5 and is a material that is made of a resin material such as silicon rubber or a fluorine-based resin and is likely to volatilize when exposed to high temperatures. Therefore, the configuration C: lid / low-rigidity portion 7 and configuration E: lid / high-rigidity portion 8 / low-rigidity portion 7 have a problem that the low-rigidity portion volatilizes when exposed to high temperatures. On the other hand, when the configuration D: lid / low-rigidity portion 7 / high-rigidity portion 8 is adopted, the volatilization of the low-rigidity portion 7 is suppressed because the low-rigidity portion 7 is covered with the high-rigidity portion 8. The problem is solved.

  Therefore, FIG. 10 shows that the configuration D: lid / low rigidity portion 7 / high rigidity portion 8 is most preferable. Incidentally, in the evaluation of FIG. 10, in the sample of the configuration D: lid / low-rigidity portion 7 / high-rigidity portion 8, the material of the lid portion is kovar, the layer thickness is 0.1 mm, and the Young's modulus is 90 MPa, while the low The material of the rigid portion 7 is silicon rubber, 0.1 mm and Young's modulus is 45 MPa, and the material of the high-rigidity portion 8 is stainless steel, the layer thickness is 0.1 mm, and the Young's modulus is 180 MPa. At this time, the ratio of Young's modulus of low rigidity / Young's modulus of high rigidity is 0.25.

  In addition, the same effects as the sample of Example 1 (Configuration D) can be obtained with the configuration of Embodiment 2. In FIG. 10, the rightmost parameter is a sample having the configuration of the second embodiment, and is the configuration F: high-rigidity portion 8 / low-rigidity portion 7 / lid 5 in the order of stacking from the bottom. According to FIG. 10, the result of the configuration D: lid / low rigidity portion 7 / high rigidity portion 8 is almost the same.

  Further, FIG. 5 is shown as a specific example of the vibration waveform of the sample of Example 1, but the vibrations 9 and 10 of the lid portion 4 due to unnecessary vibration from the outside are 1 in the plane of the lid portion 4 with respect to the X-axis direction. The vibration having two vibration nodes and two vibration antinodes, and the vibration of the sample lid portion 4 of the first embodiment, which vibrates in the opposite directions in the Z-axis direction around this node, is subjected to shear stress. It is generated by using. Further, the plane of the lid 5 has one vibration node and two vibration nodes in the X-axis direction, and the plane of the lid 5 has one vibration node and two vibrations in the Y-axis direction. It has been confirmed that the vibration with the belly is also effective.

(Example 3)
Next, regarding the unnecessary vibration generated from the angular velocity sensor element 3, that is, leakage vibration, a structure for suppressing transmission of the unnecessary vibration, that is, leakage vibration from the package part 2 to the outside by the vibration-resistant structure unit 6 will be described. To do.

  FIG. 11 is a diagram for confirming the influence on the angular velocity sensor 1 when five samples of the comparative example and Example 1 are prepared and unnecessary vibration is applied from the angular velocity sensor element 3. Incidentally, the sample of Example 1 has a configuration D: lid / low-rigidity portion 7 / high-rigidity portion 8; the material of the lid portion is kovar, the layer thickness is 0.1 mm, the Young's modulus is 90 MPa, and the low-rigidity portion 7 The material is silicon rubber with a layer thickness of 0.1 mm and a Young's modulus of 45 MPa, and the material of the high rigidity portion 8 is stainless steel with a layer thickness of 0.1 mm and a Young's modulus of 180 MPa. At this time, the ratio of Young's modulus of low rigidity / Young's modulus of high rigidity is 0.25.

  In the evaluation of Example 2, the angular velocity sensor element 3 vibrates by vibrating the circuit board 13 (FIG. 3) from the outside, and the output at that time is detected. On the other hand, the evaluation of Example 3 is performed. Is an unnecessary vibration from the angular velocity sensor element 3, and the generation source of the unnecessary vibration is the angular velocity sensor element 3, which causes the circuit board 13 to vibrate.

  In Example 3, both ends of the circuit board 13 are fixed, and an environment is assumed in which unnecessary vibration from the angular velocity sensor element 3 is applied in a pseudo manner. Moreover, as an evaluation method of Example 3, unnecessary vibration was applied from the angular velocity sensor element 3 with both ends of the circuit board 13 fixed, and the amplitude of vibration of the circuit board 13 was directly measured.

  In FIG. 11, the horizontal axis is a sample of the comparative example and Example 1, and the vertical axis is the vibration of the circuit board 13 by fixing both ends of the circuit board 13 when unnecessary vibration is applied from the angular velocity sensor element 3. It is the figure which plotted the amount of amplitudes. According to FIG. 11, while the amplitude of the sample of the comparative example is large, the amplitude of the sample of Example 1 is improved and reduced, and the effect of suppressing unnecessary vibration from the angular velocity sensor element 3 to the outside is reduced. Was confirmed. The principle of vibration suppression is the same as that of the second embodiment in that shear stress is used.

DESCRIPTION OF SYMBOLS 1 Angular velocity sensor 2 Package 3 Angular velocity sensor element 4 Cover part 5 Lid 6 Vibration-resistant structure part 7 Low-rigidity part 8 High-rigidity part 9 Vibration 10 generated from unnecessary vibration Vibration waveform 11 canceling vibration waveform 9 Shear stress 12 Support point 13 Circuit board 14 Fixed part

Claims (7)

A piezoelectric vibration type angular velocity sensor element; a package for fixing the angular velocity sensor element; and a lid for sealing the package;
The lid portion includes a lid that directly seals the package, and a vibration-resistant structure portion laminated on the lid.
The vibration-resistant structure portion is composed of at least one pair of two-layer structures of a low-rigidity portion 7 made of a material having a lower rigidity than the lid portion and a high-rigidity portion made of a material having a high rigidity equal to or higher than the lid portion. The angular velocity sensor, wherein the low-rigidity portion is disposed between the lid and the high-rigidity portion.   The lid is made of a metal material such as Kovar or stainless steel, the low-rigidity portion is made of a resin material such as silicon rubber or a fluorine-based resin, and the high-rigidity portion is made of a metal material such as Kovar or stainless steel. The angular velocity sensor according to claim 1.   The angular velocity according to claim 1, wherein a ratio of Young's modulus between the low-rigidity portion and the high-rigidity portion (Young's modulus of the low-rigidity portion / Young's modulus of the high-rigidity portion) is 0.50 or less. Sensor.   4. The angular velocity sensor according to claim 1, wherein a layer thickness ratio (layer thickness of the low rigidity portion / layer thickness of the high rigidity portion) of the low rigidity portion and the high rigidity portion is 0.2 or more. .   The angular velocity sensor according to claim 1, wherein the vibration-resistant structure portion has a smaller area than the lid.   The angular velocity sensor according to claim 1, wherein the vibration-resistant structure portion is stacked on the opposite side of the lid with respect to the angular velocity sensor element. The angular velocity sensor according to claim 1, wherein the vibration-resistant structure portion is stacked on the angular velocity sensor element side with respect to the lid.

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