WO2006104134A1

WO2006104134A1 - Tuning fork type oscillator mounting structure of oscillating gyroscope

Info

Publication number: WO2006104134A1
Application number: PCT/JP2006/306255
Authority: WO
Inventors: Kenji Kuramoto; Mitsuhiro Nakajima; Takeshi Hosokawa; Atsushi Ochi; Takeshi Inoue; Mitsuru Yamamoto
Original assignee: Japan Aviation Electronics Industry, Limited; Nec Corporation
Priority date: 2005-03-28
Filing date: 2006-03-28
Publication date: 2006-10-05
Also published as: JP2006275630A; JP3959097B2

Abstract

A tuning fork type oscillator mounting structure of an oscillating gyroscope capable of reducing driving oscillation leaking to detection legs by suppressing the occurrence of vertical asymmetry of strain produced in a turning fork type oscillator when the oscillator is fixedly supported by a support member. The magnitude of the oscillating strain of an oscillator body part (10) is distributed to be larger on drive leg (11a, 11b, 11c) side and smaller on the detection legs (12a, 12b, 12c) side. Accordingly, the center (20c) of a support member fixed area (1a) is not positioned at the gravity center (10c) of the body part (10) but positioned on the detection leg side thereof apart by a distance D of 30% or more of the length L of the support member fixed area (1a) from the gravity center (10c) of the body part (10). As compared with a conventional case in which the center (20c) of the support member fixed area is positioned at the same position as the gravity center (10c) of the oscillator, the constraint of the support member against the drive oscillation on the body part (10) is remarkably reduced. As a result, the drive oscillation leaking to the detection legs is reduced and the angular velocity detection accuracy of the tuning fork type oscillating gyroscope can be increased.

Description

Vibration gyro tuning fork type vibrator mounting structure

Technical field

TECHNICAL FIELD [0001] The present invention relates to a tuning fork type vibration gyro comprising a package and a tuning fork type vibrator in which a driving leg and a detection leg are coupled by a body part, and in particular by supporting the body part using a package as a fulcrum. The present invention relates to a vibrator mounting structure in which a tuning fork type vibrator is mounted on a package.

Background art

[0002] This type of tuning-fork type vibration gyro is described in Patent Document 1 or Patent Document 2. The basic structure and operation of a tuning fork type vibration gyro described in Patent Document 1 or Patent Document 2 will be described with reference to FIG. Fig. 10 is a diagram showing a tuning fork vibrator for a vibrating gyroscope. Fig. 10 (A) shows the state when there is no rotation input to the tuning fork vibrating gyroscope, and Fig. 10 (B) shows the tuning fork vibrating gyroscope. Represents the state when there is rotation input. In the figure, 111a and 111b are excitation drive legs (excitation drive side arm in Patent Document 1), and 112a and 112b are vibration detection legs (vibration detection side arm in Patent Document 1). Excitation drive legs 1 11a and 11 lb are paired with each other and vibrate in opposite phases. The drive legs 11 la and 1 l ib for excitation are referred to as drive legs 111 (drive side arm in Patent Document 1). The vibration detection legs 112a and 112b are paired with each other and vibrate in opposite phases. The detection legs 112a and 112b for vibration are referred to as detection legs 112 (detection side arms in Patent Document 1). The trunk portion 10 is a rectangular parallelepiped, and its planar shape (the shape of the upper surface 10a) is a square (not necessarily a square). Each surface of the body 10 is represented by reference numeral 10a on the top surface, represented by reference numeral 1 Ob on the bottom surface (not shown in the figure), represented by 10c on the end surface on the drive leg 111 side, and on the end surface on the detection leg 112 side (illustration). (Not shown in the figure) is represented by 10d, one side is represented by 10e, and the other side (not shown in the figure) is represented by 10f. The upper surface 10a and the bottom surface 10b are referred to as main surfaces. The tuning-fork type vibration gyro in Patent Document 1 and Patent Document 2 is provided with one non-excitation drive leg (non-excitation drive side arm in Patent Document 1) between the excitation drive legs 111a and 1 ib. One non-vibration detection leg (patented between the vibration detection legs 112a and 112b The non-vibration detection arm in Document 1 is provided, but the non-excitation drive leg and non-vibration detection leg are provided for vibration stabilization and are not necessary for explanation of the principle. This is omitted in the tuning fork type vibration gyro shown in FIG.

[0003] The body 10, the drive legs 11 la and 11 lb for excitation, and the detection legs 112a and 112b for vibration are made of one piezoelectric single crystal body, and have a shape cut out from a single plate-like piezoelectric single crystal. Eggplant. Examples of the piezoelectric single crystal include quartz crystal, lithium niobate, and langasite. The body 10, the drive leg 111a, 111b for excitation and the thickness of the detection leg 112a, 112b for vibration are the same. In a state where the excitation driving legs 11 la and 11 lb are not excited, that is, in a stationary state, the axes of the excitation driving legs 111a and 111b and the axes of the vibration detection legs 112a and 112b are the end face 10c and Each is perpendicular to 1 Od. The axes of the excitation drive leg 111a and the vibration detection leg 112a are on the same axis. Similarly, the axes of the excitation drive leg 11 lb and the vibration detection leg 112b are on the same axis. Further, the driving leg 11 la and 11 lb for excitation are symmetrical with respect to a plane passing through the center of gravity of the body part 10 and parallel to the side face 10e, and the detection legs 112a and 112b for vibration are also symmetrical. Driving electrodes 111a and 111b for excitation and detection legs 112a and 112b for vibration are provided with driving electrodes and detection electrodes, respectively (the electrodes are not shown).

When an AC voltage for excitation is applied to the drive electrode in the tuning fork type vibration gyro having the structure shown in FIG. 10, the excitation drive legs 11 la and 11 lb are placed in a plane parallel to the upper surface 10a. It vibrates in opposite directions, that is, in opposite phase. This vibration is the driving vibration in the tuning fork type vibration gyro. The drive vibration is vibration in a plane parallel to the main surface (the upper surface 10a and the bottom surface 10b) of the body portion 10, and such vibration in a plane parallel to the main surface is referred to as in-plane vibration. In-plane vibration is represented by arrows Ha and Hb in Fig. 10 (A). In this state, if rotation of the angular velocity ω is input around the input shaft shown in Fig. It becomes the vibration of the same frequency which shifted. This vibration is called Coriolis vibration in the sense of vibration based on Coriolis. When the leg vibrates so that the displacement of the leg end is within the range of a, the absolute value of the leg end velocity is zero when the displacement of the leg end is a, and the displacement of the leg end is zero. It becomes the maximum at the time of. In the tuning fork type vibration gyro having the structure of FIG. 10, when the rotation of the angular velocity ω is inputted around the input shaft of FIG. Coriolis acts on b and Coriolis vibrations Ca and Cb are generated respectively. The Coriolis vibrations Ca and Cb are vibrations in a direction perpendicular to the main surface of the body 10, and their phases are opposite to each other. The vibration in the direction perpendicular to the main surface of the body portion 10 is referred to as surface vertical vibration.

[0005] Since the body portion 10 is plate-shaped, it has extremely high rigidity against vibration in a direction parallel to the main surface, that is, in-plane vibration, and vibration in a direction perpendicular to the other main surface, It exhibits relatively low stiffness against vertical vibration. Therefore, among the vibrations generated in the excitation drive legs 111a and 111b, the drive vibrations Ha and Hb which are in-plane vibrations hardly propagate to the vibration detection legs 112a and 112b, and the other surface vertical vibrations are Coriolis. The vibrations Ca and Cb propagate to the vibration detection legs 112a and 112b with high efficiency. The core vibrations propagated to the vibration detection legs 112a and 112b are detected vibrations Da and Db in the tuning fork type vibration gyro. The tuning fork type vibration gyro detects the angular velocity ω by taking out the voltage appearing in the vibration detection legs 112a and 112b as an electric signal by the detection electrodes by the detection vibrations Da and Db.

In the tuning fork type vibration gyro, the drive vibration component appearing on the vibration detection legs 112a and 112b is noise, and the detected vibration component (Da, Db) is a signal. Therefore, the ratio of the drive vibration component to the detected vibration component (Da, Db) in the vibration detection legs 112a, 1 12b is the signal-to-noise ratio (SZN ratio). Therefore, to detect the angular velocity ω with high accuracy, It is necessary to reduce drive vibration components that leak and appear in the detection legs 112a and 112b. The drive vibration component leaking to the vibration detection legs 112a, 1 12b becomes a bias for the signal component [detection vibration component (Da, Db)]. If this bias is unstable, the detection accuracy of the angular velocity ω is lowered.

[0007] In the tuning fork type vibration gyro of Patent Document 1 and Patent Document 2, a support member made of quartz glass

The tuning fork vibrator is supported at the center of gravity by the holding body in Patent Document 1. Its center of gravity is in the middle of the torso.

Patent Document 1: JP 2001-255152

Patent Document 2: JP 2001-208545

Patent Document 3: Japanese Patent No. 2518600

Patent Document 4: JP-A-11-173857

Disclosure of the invention

Problems to be solved by the invention [0008] FIG. 5 is a schematic diagram showing a variation in distortion appearing in the vibrator when the body of the tuning fork vibrator is supported by a support member. FIGS. 5A and 5B show distortions appearing on the body 10 when drive vibration is applied to the body in a state where it is not supported by the support member. 5 (C) and 5 (D) show the case where the center of gravity of the body part 10 is supported by the support member 2 and driving vibration is applied to the body part 10 with the body part 10 mounted on the package substrate 30. The distortion that appears in the torso appears. 5 (C) and 5 (D), the support member 2 is fixed to the center of gravity of the body 10 and the package substrate 30.

[0009] FIG. 5 (A) shows that when the vibration due to the vibration displacements a 1 and j81 of the legs opposite to each other is generated in the trunk 10 by the driving vibration excited by the driving leg, In this case, distortions al and bl in opposite directions occur, and distortions cl and dl in opposite directions occur in the lower part of the body 10, indicating that al = bl = cl = dl. Fig. 5 (B) shows that when the vibration caused by the vibration displacement α 2 and | 82 of the legs opposite to each other is generated in the trunk 10 due to the drive vibration excited by the drive legs, The opposite strains a2 and b2 occur, and the lower part of the body 10 has opposite strains c2 and d2, which indicates that a2 = b2 = c2 = d2.

[0010] On the other hand, FIG. 5 (C) shows the case where stress is generated in the trunk 10 due to the vibration displacements α1 and j81 of the legs opposite to each other due to the drive vibration excited by the drive leg. Distortions al and bl opposite to each other occur at the top of 10 and distortions cl and dl opposite to each other occur at the bottom of the body 10, indicating that al = bl> cl = dl. ing. FIG. 5 (D) shows that when the stress due to the vibration displacement α 2 and | 82 of the legs opposite to each other is generated in the trunk 10 by the driving vibration excited by the driving leg, It is shown that forces a2 and b2 opposite to each other are generated in the upper part, and forces a2 = b2> c2 = d2 are generated in the lower part of the body 10 to generate opposite strains c2 and d2.

[0011] As shown in Figs. 5 (C) and (D), when the body 10 of the tuning fork vibrator is supported by the support member 2, the strain at the upper part of the body 10 and the distortion at the lower part are large. The vertical distortion of the trunk distortion occurs. When a vertical asymmetry is generated in the distortion of the body 10, vibration in a direction perpendicular to the drive vibration, that is, a plane vertical vibration component is generated in the body. This surface vertical vibration component appears on the vibration detection leg as a leakage drive vibration and is in the same vibration direction as the detection vibration. Therefore, it becomes a noise component with respect to the detection vibration and decreases the accuracy of angular velocity detection. 6 to 9 are simulation diagrams of trunk distortion when the center of gravity of the trunk 10 of the tuning fork vibrator is not supported and when it is supported by the support member 2. 6 to 9, reference numeral 10 denotes a body, 11a and l ib denote excitation driving legs, 11c denotes non-excitation driving legs, 12a and 12b denote vibration detection legs, and 12c denotes a non-vibration detection leg. These simulation diagrams are distribution diagrams of displacements in the trunk 10 and the drive legs and the detection legs in the vicinity of the trunk 10. Figures 6 to 9 show the same pattern in the displacement distribution diagram measured by the force laser Doppler displacement meter drawn by computer simulation. Figure 6 shows the distribution of displacement in the driving vibration direction (in-plane vibration direction) when the body part 10 is not supported. Figure 7 shows the direction perpendicular to the driving vibration when the body part 10 is not supported (plane vertical vibration direction). ) Is a distribution diagram of displacement. Fig. 8 is a distribution diagram of displacement in the driving vibration direction (in-plane vibration direction) when the center of gravity of the body 10 is supported by the support member 2. Fig. 9 is a diagram when the center of gravity of the body 10 is supported by the support member 2. FIG. 6 is a distribution diagram of displacement in a direction perpendicular to the drive vibration (plane vertical vibration direction). When FIG. 9 is compared with FIG. 7, when the center of gravity of the body 10 is supported by the support member 2, surface vertical vibrations appear greatly on the body 10 and the detection legs 12 on the detection legs 12 a, 12 b, 12 c side. I understand.

In a tuning fork type vibration gyro, it is inevitable to employ a vibrator mounting structure in which a vibrator is mounted on a package. Patent Documents 1 and 2 show a structure in which a cylindrical support member is fixed to the center of gravity of a tuning fork vibrator with an adhesive or the like to support the vibrator. In the vibrator mounting structure adopted in the tuning fork type vibration gyro of Patent Documents 1 and 2, the tuning fork type vibrator is supported by the same principle as the vibrator mounting structure shown in the schematic diagram of FIG. Asymmetry occurs and appears as a leakage drive vibration on the vibration detection leg, becomes a noise component for the detected vibration, and decreases the accuracy of angular velocity detection. As a structure for suppressing drive vibration from leaking to the vibration detection leg, those described in Patent Document 3 and Patent Document 4 have been proposed.

FIG. 11 (FIG. 1 in Patent Document 3) shows a rotation speed sensor 10 (tuning fork type vibration gyro) described in Patent Document 3. The rotational speed sensor 10 includes a housing 11, a double ended (ie, H type) tuning fork 13, and a rotational speed detection circuit 21. The housing 11 has a lid 12, a base 14, and a mounting structure 15. The tuning fork 13 is etched by a single crystal force of the piezoelectric material. This material is made of quartz, lithium niobate (Lithium

Niobate) or other piezoelectric material. FIG. 12 (FIG. 3 in Patent Document 3) shows a tuning fork 13 described in Patent Document 3. The main body 16 of the tuning fork 13 has a surrounding frame 30 and an internal cavity 33. The tuning fork 13 has excitation branches (driving tines) 31 and 32 and pickup branches (44 and 45). The tuning fork 13 also has a single dedicated mounting base 57 in the cavity 33. The mounting base 57 is spaced from the inner peripheral surface 18 of the frame 30, is surrounded by it, and is disposed at the center thereof. The mounting base 57 is coupled to the inner peripheral surface 18 by a suspension device 59 formed by cross bridges 61 and 62 and suspension bridges 64 to 67. The peripheral surface 71 of the mounting base 57 is spaced from the inner peripheral surface 18 of the main body 16 by an opening 73 in the + Y direction and by an opening 74 in the −Y direction.

FIG. 13 (FIG. 4 in Patent Document 3) shows the base portion 14 and the mounting structure 15 of the housing 11 described in Patent Document 3. The mounting structure 15 is a pedestal 94. This bedestal 94 has substantially the same dimensions as the mounting surface 59 of the tuning fork 13. Returning to FIG. 11 and FIG. 12, the tuning fork 13 is attached to the pedestal 94. The back surface 70 of the mounting base 57 is a single dedicated mounting surface of the tuning fork 13. This surface is fixed to the mounting surface 76 of the pedestal 94. This fixing is preferably performed by a conventional thermoplastic adhesive or epoxy resin. As a result, the tuning fork 13 can be mounted in the housing 11 only at the single dedicated mounting surface 70. A suspension device 59 couples the mounting base 57 to the frame 30. Pedestal 94 is made of stainless steel, aluminum, nickel alloy Monel 400 or ceramics. The polished silicon or quartz wafer may be “stretched” according to the wafer force and fixed to the base 14 using epoxy resin. In the tuning fork type vibration gyro of Patent Document 3, the vibrator mounting structure is composed of a pedestal 94, a suspension device 59, and a mounting base 57.

In such a vibrator mounting structure described in Patent Document 3, since the internal cavity 33 is provided in the main body 16 of the tuning fork 13, it is necessary to apply a deep etching force to the main body 16 of the tuning fork 13. When the tuning fork 13 is made of a material for which an efficient etching method has not been established, for example, langasite, the vibrator mounting structure described in Reference 3 cannot be applied. In addition, the vibrator mounting structure of the cited document 3 includes a suspension device 59 in the internal cavity 33, so that the structure is complicated, expensive, and difficult to downsize. FIG. 14 is a view showing a supporting means for supporting the vibrator 50 in the vibratory gyroscope of Patent Document 4. As shown in FIG. This support means is also an example of a vibrator mounting structure in which the vibrator 50 is mounted on a package. Reference numerals 51a, 51b, 52, and 53 in FIG. 14 denote support means. In FIG. 14 (a), the protrusions 51A and 51B are arranged vertically so as to sandwich the support hole 47 of the vibrator 50, and the vibrator 50 is also pressure-bonded by the protrusions 51A and 51B. 14 (b) and 14 (c), a pin 52a is provided on the projection 52, and a hole 53a is provided on the other projection 53. The protrusions 52 and 53 are arranged vertically so as to sandwich the support hole 47 of the vibrator 50, the pin 52a is inserted into the support hole 47, penetrated, and further inserted into the hole 53a. The transducer 50 is crimped from the direction.

As in the vibrator mounting structure of Patent Document 3, the vibrator mounting structure of Patent Document 4 in FIG. 14 also needs to form support holes 47 in the vibrator 50. Therefore, when the vibrator 50 is made of a material for which an efficient etching method has not been established, for example, langasite, the vibrator mounting structure of the cited document 4 cannot be applied. Further, in the vibrator mounting structure of the cited document 4, the support hole 47 is provided in a region where the detection vibration is minimized, but the vibration as shown in FIG. 10 that couples the driving leg and the detection leg via the trunk. As shown in the displacement distribution diagrams of FIGS. 6 to 9, the drive vibration (in-plane vibration) is not small even in the region where the detected vibration (plane vertical vibration) is small. Even if the support hole 47 is provided in the area, the drive vibration is not small in that area. .

[0020] In the vibrator mounting structure of Patent Documents 1 and 2 listed above, as shown in Fig. 5, by supporting the body 10 of the tuning fork type vibrator with the support member 2, the body 10 is distorted. Due to the vertical asymmetry, the drive vibration leaked to the detection legs, which hindered the improvement in the angular velocity detection accuracy of the tuning fork type vibration gyroscope, and the stability of the detection accuracy was also impaired. In addition, the vibrator mounting structure described in Patent Document 3 cannot be applied to tuning fork vibrators made of materials for which an efficient etching method has not been established, such as Langasite, and the structure is complicated and expensive. Yes, downsizing is difficult. Further, the vibrator mounting structure described in Patent Document 4 cannot be applied to a tuning fork made of a material for which an efficient etching method has not been established, such as langasite, and the driving leg and the detection leg are connected to the body. The tuning fork as shown in Figure 10 The type vibrator cannot be put into practical use due to the large loss of vibration energy.

Therefore, an object of the present invention is to reduce the drive vibration leaking to the detection leg by suppressing the occurrence of vertical asymmetry of the distortion generated in the vibrator by supporting the tuning fork vibrator with the support member, As a result, it is intended to improve the accuracy and stability of the angular velocity detection of the tuning fork type vibrating gyroscope. Another object of the present invention is a simple structure that can be applied to a tuning fork type vibrator made of a material for which an efficient etching method has not been established, for example, langasite, and has little loss of vibration energy. It is to provide a vibrator mounting structure that can be miniaturized. Means for solving the problem

In order to solve the above-described problems, the present invention provides the following means.

[0023] (1) A pair of excitation drive legs and a pair of vibration detection legs, and a body part that couples the excitation drive legs and the vibration detection legs, and is interposed between the body part and the package In the vibrator mounting structure of a tuning fork vibrator having a support member fixing region on the bottom surface of the moon and a support member fixed to the support member mounting region of the package,

When the point at which the center of gravity of the tuning fork vibrator is projected onto the bottom surface is referred to as a bottom surface center of gravity position, the center of gravity position of the support member fixing region is on the longitudinal direction line of the tuning fork type vibrator passing through the bottom surface center of gravity position. The vibrator mounting structure, wherein the vibrator mounting structure is located at a position close to the detection leg side from the position of the bottom center of gravity.

(2) The distance between the gravity center position of the support member fixing region and the bottom surface gravity center position is 30% or more of the length of the support member fixing region in the longitudinal direction. The vibrator mounting structure according to (1) above.

[0025] (3) —a pair of excitation drive legs and a pair of vibration detection legs, and a trunk portion that couples the excitation drive legs and the vibration detection legs, and between the trunk portion and the package. In the vibrator mounting structure of a tuning fork vibrator having an intervening support member fixing region on the bottom surface of the moon and the support member mounting region of the package,

When a point at which the center of gravity of the tuning fork vibrator is projected onto the bottom surface is referred to as a bottom surface center of gravity position, the center of gravity position of the support member fixing region is the bottom surface center of gravity position or the tuning fork type passing through the bottom surface center of gravity position It is on the longitudinal direction line of the vibrator and is located at the position near the detection leg side from the position of the center of gravity of the bottom surface, The shape of the support member fixing region is symmetric with respect to the longitudinal direction line, and is sharpened toward the drive leg side.

A vibrator mounting structure characterized by this.

[0026] (4) The vibrator mounting according to (3), wherein the shape of the support member fixing region is a hexagon, or a trapezoid or a triangle having the detection leg side as a base. Construction. The invention's effect

[0027] According to the present invention described above, drive vibration that leaks to the detection leg by suppressing the occurrence of vertical asymmetry of the distortion generated in the vibrator due to the tuning fork vibrator supported by the support member. Therefore, it is possible to provide a vibrator mounting structure that can improve and stabilize the angular velocity detection accuracy of a tuning-fork vibration gyro. Furthermore, according to the present invention, it can be applied to a tuning fork type vibrator made of a material for which an efficient etching method has not been established, for example, langasite, and has a simple structure with a small loss of vibration energy and a small size. It is possible to provide a resonator mounting structure that can be manufactured at low cost.

BEST MODE FOR CARRYING OUT THE INVENTION

Next, embodiments of the present invention will be described, and the present invention will be described more specifically with reference to the drawings. FIG. 1 is an exploded perspective view showing a tuning-fork type vibration girder having a vibrator support structure according to a first embodiment of the present invention. FIG. 2 shows that the center point of the support member fixing region in the tuning fork vibrator of FIG. 1 is a position that is more than 30% closer to the detection leg side from the center of gravity of the tuning fork vibrator (the first aspect of the invention). FIG. 2 is a plan view of the bottom surface of the tuning fork vibrator showing the first embodiment. FIG. 3 is a diagram for explaining that the shape of the support member fixing region on the surface of the tuning fork vibrator is sharp toward the drive leg side (second embodiment of the present invention). (A) is a plan view of the bottom surface of the tuning fork vibrator, (B) is a plan view of a hexagonal support member fixing region, and (C) is a pentagonal support member fixing. It is a top view of an area. FIG. 4 is a diagram for explaining that the shape of the support member fixing region on the surface of the tuning fork vibrator is a trapezoid or a triangle with the detection leg side as a base (third embodiment of the present invention). (A) is a plan view of the bottom surface of the tuning fork vibrator, (B) is a plan view of a trapezoidal support member fixing region, and (C) is a triangular support member fixing region. FIG. In FIGS. 1 to 4, 1 is a tuning fork type vibrator, la is a support member fixing region in the tuning fork type vibrator 1, 2 is a support member, 3 is a package, 10 is a body part, 10c is a body part 10 11a, l ib is an excitation drive leg, 11c is a non-excitation drive leg, 12 is a detection leg, 12a and 12b are vibration detection legs, 12c is a non-vibration detection leg, 20c is Center of support member fixing area la, 30 is a package substrate, 30a is a support member mounting area, 31a, 31b, 32a, 32b, 33a, 33b, 34a, 34b, 35a, 35b, 36a, 36b, 37a, 37b are terminals It is.

In FIG. 1, the tuning fork vibrator 1, the support member 2, and the package 3 are shown in an exploded manner.

In the state where the tuning fork vibrator 1, the support member 2, and the package 3 are combined, the lower surface of the support member 2 is fixed to the support member mounting region 30a on the upper surface of the package substrate 30 with an adhesive, and the upper surface of the support member 2 is The tuning fork vibrator 1 is fixed to the support member fixing region la on the bottom surface of the body 10 with an adhesive. The state in which the members denoted by reference numerals 1, 2, and 3 are joined is a state in which the support member 2 supports the fixing region la of the tuning fork vibrator 1 with the support member mounting region 30a as a fulcrum. The vibrator 1 is mounted on the package 3 via the support member 2.

[0031] The drive leg 11 in the tuning fork vibrator 1 includes a non-excitation drive leg 11c in addition to the excitation drive legs 11a and l ib corresponding to the excitation drive legs 111a and 11 lb in the drive leg 111 in FIG. Prepare. Similarly, the detection leg 12 in the tuning fork type vibrator 1 includes a non-vibration detection leg 12c in addition to the vibration detection legs 12a and 12b corresponding to the vibration detection legs 112a and 112b in the detection leg 112 of FIG. . The non-excitation drive leg 11c and the non-vibration detection leg 12c are also provided as a non-excitation drive side arm and a non-vibration detection side arm in the tuning fork type vibration gyroscopes of Patent Documents 1 and 2. Although it is provided to stabilize the vibration of the drive leg 11 and the detection leg 12, it is not important for the operation of the present invention, and even if these legs 11c and 12c are omitted as shown in FIG. Therefore, further description of the non-excitation drive leg 11c and the non-excitation detection leg 12c will be omitted below. The operation of the tuning fork type vibrator 1 in the tuning fork type vibration gyro shown in FIG. 1 is the same as that of the tuning fork type vibrator shown in FIG.

A tuning fork vibrator 1 in FIG. 1 is a single crystal piezoelectric body made of langasite. A driving electrode is provided on at least one of the excitation driving legs 11a and l ib in the tuning fork resonator 1 and vibrates. At least one of the detection legs 12a and 12b for detection is provided with a detection electrode, but the illustration is omitted. The drive electrode and the detection electrode are connected to any of the terminals 31a, 31b, 32a, 32b, 33a, 33b, 34a, 34b, 35a, 35b, 36a, 36b, 37a, or 37b with bonding wires. However, these bonding wires are not shown.

[0033] FIG. 2 shows a position where the center point 20c of the support member fixing region la in the tuning fork vibrator 1 of FIG. 1 is shifted from the center of gravity 1 Oc of the tuning fork vibrator 1 by D to the detection leg 12 side. FIG. 2 is a plan view showing a certain state (a first embodiment of the present invention). The center-of-gravity position 10c is a position where the center of the tuning fork vibrator 1 is projected onto the bottom surface of the trunk portion 10, and corresponds to the above-described bottom-surface center-of-gravity position. Here, referring to FIG. 8, when looking at the distribution of the displacement in the in-plane vibration direction due to the in-plane vibration in the body 10 (displacement due to the drive vibration), the in-plane distortion is large on the drive leg 11 side. Small on the side. In addition, referring to Fig. 9, looking at the distribution of displacement due to surface vertical vibration in the body 10 (surface vertical displacement due to detected vibration), the displacement in the in-plane vibration direction is still detected to be large on the drive leg 11 side. Leg 1 Small on the 2 side. Therefore, the point where the distortion of the body portion 10 due to the combined vibration of the drive vibration and the detection vibration is minimized is closer to the detection leg 12 side than the center of gravity position 10c of the tuning fork vibrator 1. In Fig. 2, the center of the support member fixing area la (coincides with the center of gravity of the area la) 20c is 30% or more of the length L of la, and it is separated from the center of gravity 10c by a distance D (D≥0.3L). Therefore, compared with the conventional case where the center 20c of the support member fixing region la is located at the same Cf as the center of gravity 10c of the vibrator, the restraint of the support member 2 against the drive vibration in the body 10 is extremely small. Become. Therefore, the upper and lower asymmetry of the strain is remarkably small between the upper side (the side not in contact with the support member 2) and the lower side (the side in contact with the support member 2 and the support member fixing region la side) of the body 10 and detection. Drive vibration that leaks to the leg 12 is reduced, and the angular velocity detection accuracy of the tuning-fork type vibration gyro is improved and stabilized.

As described above, in the embodiment of FIGS. 1 and 2 (the first embodiment), the center of the support member fixing region la of the trunk portion 10 is distorted in the distribution of vibration strain. Is in the point where becomes small. Therefore, in the first embodiment, the influence of the restraint of the support member 2 on the drive vibration of the body part 10 is small (on the side not contacting the support member 2) and the lower side (on the support member 2). The so-called up-down asymmetry of the strain, which is different in the magnitude of the strain on the contact side, the support member fixing area la side), is Drive vibration that leaks to the detection legs is reduced significantly, and the angular velocity detection accuracy of the tuning fork type vibration gyro is improved and stabilized.

In the embodiment shown in FIGS. 1 and 2, langasite is used as the piezoelectric crystal material constituting the tuning fork vibrator 1. Langasite is a material for which an efficient etching method has not been established, but formation of vibrator 1 and support member 2 in the manufacture of this embodiment is possible with a mechanical force using a wire saw or a turret. In addition, since there is no process that requires molding by etching, this embodiment can be easily realized.

FIG. 3 is a plan view showing a vibrator mounting structure according to the second embodiment of the present invention. 3A and 3B, the shape of the support member fixing region la in the tuning fork vibrator 1 is a hexagon and has a sharp apex toward the drive leg 11 side. In FIG. 3 (C), the shape of the support member fixing region la in the tuning fork vibrator 1 is a pentagon, and the pentagon has a sharp apex toward the drive leg 11 side. In the embodiment of FIG. 3, the length of the support member fixing region la is L, and the distance between the center of gravity position 10c of the tuning fork vibrator 1 (corresponding to the above-mentioned bottom center of gravity position) and the center of gravity 20c of the support member fixing region la. If D is D, then D≥0.

As shown in FIG. 8, the region from the vicinity of the boundary between the driving leg 11 and the trunk portion 10 to the center of gravity of the trunk portion 10 is a region showing a distribution in which the displacement of the driving vibration is large on the bottom surface of the trunk portion 10. In the embodiment of FIG. 3, the area force of the region showing the distribution where the displacement of the driving vibration is large in the area of the support member fixing region la, the driving vibration displacement force on the other hand, the center of gravity of the trough 10 is detected from the leg. The area on the 12 side is large. Therefore, compared with the conventional case where the support member fixing region la is rectangular, the restraint of the support member 2 with respect to the drive vibration in the body portion 10 is remarkably small, so that the distortion in the body portion 10 described with reference to FIG. As a result, the driving vibration leaking to the detection leg 12 is reduced, and the angular velocity detection accuracy of the tuning-fork type vibration gyro can be improved and stabilized. The vibrator 1 and the supporting member 2 can be formed by machining with a wire saw or a turret in the manufacture of the present embodiment, and there is no process that requires forming by etching. realizable.

FIG. 4 is a diagram showing a vibrator mounting structure according to the third embodiment of the present invention, and has a configuration similar to FIG. In the embodiment of FIG. 4, the length of the support member fixing region la is L, the center of gravity position 10c of the tuning fork vibrator 1 (corresponding to the above-described bottom center of gravity position) and the support member fixing region la. If the distance from the center of gravity 20c of the landing area la is D, then D≥0.

In the vibrator mounting structure of FIG. 4, the shape of the support member fixing region la is a trapezoid or a triangle with the detection leg 12 side as a base. Out of the area of the support member fixing area la, the area near the boundary between the driving leg 11 and the body 10 is a region showing a distribution in which the driving vibration distortion of the body 10 is large. The area on the detection leg 12 side is large from the center of gravity 10c showing a distribution with small distortion. Accordingly, since the restraint of the support member is reduced as a whole, the vertical asymmetry of the distortion in the trunk portion 10 described with reference to FIG. 5 is reduced, the drive vibration leaking to the detection leg 12 is reduced, and the tuning fork type vibration gyro This makes it possible to improve the angular velocity detection accuracy and improve stability. Forming the vibrator 1 and the support member 2 in the manufacture of the present embodiment can be performed by a mechanical force using a wire saw or a turret, and there is no process that requires forming by etching. Therefore, the present embodiment is easy. Can be realized.

Although the embodiments of the present invention have been specifically described above with reference to the drawings, the present invention is of course not limited to these embodiments.

Brief Description of Drawings

FIG. 1 is an exploded perspective view showing a tuning fork type vibration gyro having a vibrator support structure according to a first embodiment of the present invention.

2 is a diagram showing the first embodiment of the present invention shown in FIG. 1, and is a tuning fork showing the relationship between the center position 20c of the support member fixing region la of the tuning fork-type vibrating gyroscope and the center of gravity 10c of the trunk portion 10; FIG. 3 is a plan view of the bottom surface of the type resonator 1.

FIG. 3 is a diagram showing a second embodiment (vibrator support structure) of the present invention, in which the shape of the support member fixing region la is sharp toward the drive leg 11 side (A , B) or a pentagonal vertex (C). FIG.

FIG. 4 is a diagram showing a third embodiment (vibrator support structure) of the present invention, in which the shape of the support member fixing region la is a trapezoid (B) or a triangle (A FIG. 2 is a plan view of the bottom surface of the tuning fork vibrator 1 showing that C).

FIG. 5 is a schematic diagram showing a variation in distortion appearing in the vibrator when the body of the tuning fork vibrator is supported by a support member.

[Figure 6] Displacement distribution in the driving vibration direction (in-plane vibration direction) when the body 10 is not supported FIG.

FIG. 7 is a distribution diagram of displacement in a direction perpendicular to the drive vibration (surface vertical vibration direction) when the body 10 is not supported.

FIG. 8 is a distribution diagram of displacement in the driving vibration direction (in-plane vibration direction) when the center of gravity of the trunk portion 10 is supported by the support member 2.

FIG. 9 is a distribution diagram of displacement in a direction perpendicular to the drive vibration (surface vertical vibration direction) when the center of gravity of the trunk portion 10 is supported by the support member 2.

FIG. 10 is a diagram for explaining the operating principle of a tuning fork vibrator having a structure in which a driving leg and a detection leg are coupled to each other by a trunk.

11 is a diagram showing a rotational speed sensor 10 (tuning fork type vibration gyroscope) described in Patent Document 3. FIG. 12 is a diagram showing a tuning fork 13 described in Patent Document 3.

FIG. 13 is a view showing a base portion 14 and a mounting structure 15 of a housing 11 described in Patent Document 3.

14 is a view showing a support means for supporting the vibrator 50 in the vibration gyroscope of Patent Document 4. FIG.

Explanation of symbols

1 Tuning fork type vibrator

la Support area of tuning fork vibrator 1

2 Support member

3 Package

10 Torso

10c center of gravity

11 Driving legs

11a, l ib, 111a, 111b Excitation drive leg

11c Non-excited drive leg

12 Detection legs

12a, 12b, 112a, 112b Vibration detection legs 12c Non-vibration detection leg

20c Support member fixing area center of gravity

30 Package substrate

30a Support member mounting area

31a, 31b, 32a, 32b, 33a, 33b, 34a, 34b, 35a, 35b, 36a, 36b, 37a: Terminal

a l, β ΐ, a 2, β 2 Vibration displacement of driving leg

al, bl, a2, b2 Strain on the upper side of the body (the side where the support member is not fixed) cl, dl, c2, d2 Strain on the lower side of the body (the side where the support member is fixed)

Claims

The scope of the claims

[1] A pair of excitation drive legs and a pair of vibration detection legs, and a body part that couples the excitation drive legs and the vibration detection leg, the body part being interposed between the body part and the package, The vibrator mounting structure of a tuning fork vibrator having a support member fixing region on the bottom surface of the substrate and a support member fixed to the support member mounting region of the package!

[2] The distance between the gravity center position of the support member fixing region and the bottom surface gravity center position is 30% or more of the length of the support member fixing region in the longitudinal direction. The vibrator mounting structure described in 1.

[3] A pair of excitation drive legs and a pair of vibration detection legs, and a body part that couples the excitation drive legs and the vibration detection leg, the body part being interposed between the body part and the package, The vibrator mounting structure of a tuning fork vibrator having a support member fixing region on the bottom surface of the substrate and a support member fixed to the support member mounting region of the package!

When a point at which the center of gravity of the tuning fork vibrator is projected onto the bottom surface is referred to as a bottom surface center of gravity position, the center of gravity position of the support member fixing region is the bottom surface center of gravity position or the tuning fork type passing through the bottom surface center of gravity position It is on the longitudinal direction line of the vibrator and is located at the position near the detection leg side from the position of the center of gravity of the bottom surface,

The shape of the support member fixing region is symmetric with respect to the longitudinal direction line, and is sharpened toward the drive leg side.

A vibrator mounting structure characterized by this.

4. The vibrator mounting structure according to claim 3, wherein the shape of the support member fixing region is a hexagon, or a trapezoid or a triangle with the detection leg side as a base.