JPH10232134A - Angular velocity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an angular velocity sensor for reducing an unneeded vibration that deteriorates a detection accuracy. SOLUTION: An angular velocity sensor is constituted of a substrate 3 that is formed in a flat-plate shape, a vibrator 4 that is made of a piezoelectric single body and where various kinds of electrodes are mounted, and a fixing member 6 that is included between the vibrator 4 and the substrate 3 and is used to fix the vibrator 4 to the substrate 3. Also, the fixing member 6 that is adhered in one piece with the vibrator 4 is subjected to laser welding to the substrate 3 on the side surface (a surface that continues to a fixing surface 6b) of a connection part 32 while a fixing surface is directly adhered to the substrate 3. More specifically, the fixing member 6 is fixed to an area to the substrate 3 without including any foreign objects, thus retaining the vibrator 4 mounted to the fixing member 6 accurately and horizontally and hence preventing unneeded vibration components that prevent detection from being generated at the vibrator 4 for accurately detecting an angular velocity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angular velocity sensor used for controlling a vehicle of an automobile, preventing camera shake of a video, or as a gyro for navigation of a moving body.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. 61-294
As disclosed in Japanese Patent Publication No. 311 and the like, a vibrator made of a tuning-fork-shaped piezoelectric body is fixed to a base attached to an object to be measured which receives an angular velocity about a predetermined axis from the outside, and 2. Description of the Related Art There is known an angular velocity sensor that excites an axis in a direction perpendicular to an axis, and detects an excitation direction and a vibration state in a direction orthogonal to a predetermined axis, thereby detecting an angular velocity applied to an object to be measured from the vibration state.

In these angular velocity sensors, the vibrator is fixed to a base via a fixing member formed of metal or the like. As a fixing method, press fitting or brazing is used.

[0004]

However, in the press-fitting, the vibrator is fixed to the base with good symmetry because the base and the fixing member are deformed at the time of work, and the mounting portion is loose without being closely attached. As a result, unnecessary vibration is superimposed on the vibration of the vibrator, resulting in a problem that the detection accuracy of the angular velocity is deteriorated.

[0005] On the other hand, in the brazing, the fixing member and the base can be fixed without deforming or rattling. However, since the fixing member and the base are fixed via the brazing material, the base is fixed. Fixing member to the fixed surface (and thus the vibrator)
It is difficult to accurately maintain the horizontal level with high accuracy, and in the end, unnecessary vibration is superimposed on the vibration of the vibrator due to the deviation of the horizontality, and there is a problem that the detection accuracy of the angular velocity is deteriorated.

Further, since this kind of angular velocity sensor is formed in a very small size to be incorporated in an electronic device or the like, the capacity of the fixing member is small, and therefore, the heat applied to the fixing member is transmitted to the vibrator. Easy to do. For this reason, when the fixing member is heated by brazing, the heat is also transmitted to the vibrator, and the vibrator is heated, thereby deteriorating the polarization state of the piezoelectric body constituting the vibrator. In addition, there is a problem that the detection accuracy of the angular velocity is deteriorated.

The present invention has been made to solve the above problems.
It is an object of the present invention to provide an angular velocity sensor capable of reducing unnecessary vibration that causes deterioration of detection accuracy. In particular, claim 4
It is another object of the present invention to provide an angular velocity sensor that causes less temperature damage to a vibrator due to fixing of a fixing member and a base.

[0008]

In the angular velocity sensor according to the present invention which has been made to achieve the above object, a state in which the fixing member is in contact with or parallel to the surface of the base opposed to the base. And is welded to the base.

Therefore, according to the angular velocity sensor of the present invention,
The fixed member and the base that are welded together do not rattle at the fixed part, and the vibrator is held horizontally with respect to the base by the fixed member that abuts or is held parallel to the base. Therefore, in the vibrator, the occurrence of unnecessary vibration that hinders the detection is suppressed, and the angular velocity can be accurately detected.

[0010] In particular, when the fixing member is brought into direct contact with the base, the fixing member (and hence the vibrator) can be held horizontally and easily and accurately with respect to the base, and the assembling is easy. Can be done. The fixing member is desirably welded to the base at least at both side surfaces facing the excitation direction of the vibrator. In this case, it is possible to sufficiently secure the strength with respect to the rotational force applied to the workpiece to which the base is attached.

Further, when welding is performed on both side surfaces of the fixing member as described above, if both side surfaces are chamfered so that the width between the two side surfaces increases away from the surface facing the base, welding work can be performed. Occasionally, it is possible to suppress the oxide generated by welding from scattering around. Thus, for example, when a cover for protecting the vibrator is projection-welded to the surface of the base, it is possible to prevent oxides from adhering to the welding locations and deteriorating the strength of the projection welding. It is possible to improve the reliability of the work in the post-process and the beauty of the appearance of the device.

Further, when welding is performed on both side surfaces of the fixing member, instead of directly contacting the surface of the fixing member facing the base with the base, the vibrator of the vibrator is provided between the fixing member and the base. A spacer having a thickness larger than the vibration amplitude in the base direction may be inserted. Since the spacer does not deform when the fixing member and the base are joined, unlike the brazing material, the spacer faces the base in the same manner as in the case where the surface of the fixing member facing the base directly abuts on the base. Can be easily and accurately held horizontally. Moreover, in this type of angular velocity sensor, it is necessary to float the vibrator with respect to the base so that the vibrator does not contact the base and hinder the vibration. It can be easily realized without providing.

The welding of the base and the fixing member is performed on both sides of the fixing member as described above. For example, at least one of the base and the fixing member is thinned. A thin portion formed may be provided, and the thin portion may be used. In this case, since welding is performed at a thin portion having a small volume per area, heat escape to the base or the fixing member on which the thin portion is formed is reduced, and welding with small power becomes possible. As a result, deterioration of the polarization of the vibrator due to thermal damage received during welding can be reduced, and deterioration of detection accuracy can be prevented.

In particular, in the fixing member, a thin portion may be formed at the bottom of the hole, for example, by forming a hole toward the mounting surface to the base. In this case, the welding is performed at the bottom of the hole, and the oxide generated by the welding does not scatter outside the hole. Therefore, the same effect as when the both side surfaces of the fixing member are chamfered is more effectively achieved. Can be obtained.

In the welding of the base and the fixing member, at least one of the base and the fixing member is brought into contact with the other opposing surface so that a gap is formed between the opposing surfaces. It is also possible to provide a projecting portion for positioning between them, and to perform the process at this projecting portion. In this case, welding is performed at the projecting portion having a small volume, and there is little escape of heat to the base or the fixing member on which the projecting portion is formed. Therefore, the same effect as when the thin portion is provided can be obtained. . In addition, since the fixing member is in direct contact with the base at the protruding portion, the fixing member can be easily and accurately held horizontally with respect to the base. Since the gap is formed between the base and the base, the vibrator can be easily floated with respect to the base without providing a groove or the like on the base or using the spacer as described above.

By the way, there are various welding methods. For example, in a method of generating a large amount of heat such as electric welding, the polarization of the vibrator is deteriorated as in the case of brazing, and the detection performance is deteriorated. There is a problem of letting them do it. Therefore, the welding for joining the fixing member to the base is desirably laser welding or projection welding for forming a local joining portion. That is, in laser welding and projection welding, the welding location is local, particularly in laser welding, since the work is completed in a short time, the calorific value is small,
Therefore, the polarization of the vibrator does not deteriorate.

Further, if the fixing member is formed so that the width along the excitation direction is larger on the fixing surface to the base than the mounting surface on which the fixed end of the vibrator is mounted, the fixing state of the vibrator can be improved. Can be made more stable, and the reliability of the device can be further improved.

Here, in the vibrator, for example, processing errors and the like also cause unnecessary vibrations. Such unnecessary vibrations are detected even when the object to be measured is not subjected to an angular velocity. , Ie, an offset output. This offset output is not problematic if it is almost always constant, but it becomes a problem when it greatly changes depending on use conditions such as temperature, that is, when the temperature drift width is large.

Therefore, as a result of repeated experiments, it has been found that this offset output (ie, unnecessary vibration) is affected by the state of adhesion between the vibrator and the fixing member. If the coating is applied so as to be distributed in a symmetrical shape with respect to the center of the mounting surface of the fixing member, or if it is applied to 80% or more of the area of the fixed end and the mounting surface, the temperature drift amount of the offset output can be sufficiently reduced We found that it could be suppressed.

Therefore, it is desirable that the vibrator and the fixing member be fixed as described above. In this case, the temperature drift amount of the offset output can be suppressed to a small value.
Reliable detection can be performed in various environments.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] FIG. 1 is a perspective view showing an entire configuration of an angular velocity sensor according to a first embodiment.

As shown in FIG. 1, an angular velocity sensor 2 according to the present embodiment has a base 3 formed of a flat plate made of steel, a vibrator 4 made of a piezoelectric body alone, and having various electrodes mounted on its surface. And a fixing member 6 interposed between the vibrator 4 and the base 3 and used for fixing the vibrator 4 to the base 3.

The vibrator 4 includes a base 10 having a bottom surface 4a adhered to the fixing member 6, and a pair of arm portions 12 standing upright from the base 10 in a direction opposite to the bottom surface 4a. , 14 and are formed in a tuning fork shape. Drive electrodes 16 and 18 for inputting drive signals for exciting the pair of arm portions 12 and 14 in directions approaching / separating from each other (hereinafter, referred to as a Y-axis direction) are provided on the front surface 4b of the vibrator 4. A monitor electrode 20 for extracting a signal corresponding to the vibration state of the vibrator 4, a virtual GND electrode 22 grounded to a reference potential, a processing electrode 24 used for polarization processing of the vibrator 4, and a virtual GND electrode 22 And processing electrode 2
4 and a short-circuit electrode 25 for short-circuiting the first electrode 4 and the second electrode 4.

On both sides of the vibrator 4, detection electrodes 26 for extracting a detection signal proportional to the angular velocity Ω of rotation applied to the angular velocity sensor 2 are formed. It is connected to a pad electrode 27 formed above the front surface 4 b of the child 4 via an extraction electrode 28.

Further, the entire back surface of the vibrator 4
And a common electrode that is held at ground potential when measuring the angular velocity Ω.
The common electrode and the virtual GND electrode 22 are short-circuited by short-circuit electrodes 31 formed on both side surfaces of the vibrator 4.

On the other hand, the fixing member 6 is
Connecting portion 32 having mounting surface 6a formed in the same shape as
A small-diameter portion 34 located at the center of the connecting portion 32 and formed narrower than the width of the connecting portion 32;
And has a fixing portion 36 having a fixing surface 6b for fixing the fixing member 6 to the front end, and is formed in an E-shaped cross section.

A recess 3a is formed in the base 3 at a portion facing the connecting portion 32 of the vibrator 4 and the fixing member 6,
A pad electrode 27 and a virtual GND are provided on both edges of the
Terminals T1 to T8 to which wires W1 to W8 for extracting signals from the electrode 22, the monitor electrode 20, and the drive electrodes 16 and 18 are connected are provided. The recess 3a is
The vibrator 4 is formed to have a width and a depth such that the vibrator 4 does not come into contact with the vibrator 4 due to the drive vibration and the angular velocity Ω described later.

The vibrator 4 and the fixing member 6 are connected to the back surface (surface on the common electrode side) of the vibrator 4 and the fixing surface 6 of the fixing member 6.
The bottom surface 4a of the vibrator 4 and the mounting surface 6a of the fixing member 6 are bonded together so that b forms the same surface. Then, the fixing member 6 integrated with the vibrator 4
Is fixed to the base 3 by laser welding a side surface of the fixing portion 36 (a surface following the fixing surface 6b) in a state where the fixing surface 6b is in close contact with the base 3 directly. Here, FIG.
Welding is performed at two locations on each of the left and right side surfaces facing each other in the middle Y-axis direction (welding site S). In addition, welding may be performed not only on the left and right side surfaces of the connection portion 32 but also on the upper and lower side surfaces.

The vibrator 4 includes a fixing member 6 and a base 3.
Before assembling, the drive electrodes 16, 18, the monitor electrode 20, and the processing electrode 24 are set to the same potential, and these electrodes 1
By applying a predetermined voltage between the common electrodes 6, 18, 20, and 24, a polarization process for setting the polarization direction of the vibrator 4 made of a piezoelectric body in a direction indicated by a white arrow in the drawing is performed in advance. Have been.

The angular velocity sensor 2 configured as described above
When an AC signal having a predetermined frequency and a phase opposite to each other is applied to each of the drive electrodes 16 and 18 as a drive signal, the vibrator 4 is excited in response thereto, and the pair of arms 12 and 14 approach / separate from each other. Then, a symmetrical vibration (hereinafter referred to as a driving vibration) is repeated along the Y axis. When the driving vibration is being performed, the monitor electrode 20 outputs a monitor signal according to the vibration state of the driving vibration. The monitor signal is fed back to, for example, a drive signal generation circuit, and is used to maintain stable drive vibration.

When the vibrator 4 receives an angular velocity Ω about the axis along the direction in which the arms 12 and 14 are erected (hereinafter, referred to as the Z-axis direction) during the driving vibration, the rotation is induced. Arm portions 12, 14 due to the Coriolis force
Is a direction orthogonal to both the Y axis and the Z axis (hereinafter referred to as
Along the X-axis direction). A voltage signal proportional to the angular velocity Ω is induced on the detection electrode 26 by the compressive or tensile stress generated in the arms 12 and 14 based on the deflection, and this is detected as a detection signal.

As described above, in the angular velocity sensor 2 of the present embodiment, the side surface of the fixing member 6 is locally laser-welded while the fixing surface 6b of the fixing member 6 is directly adhered to the base 3. As a result, the fixing member 6 is fixed to the base 3. Therefore, according to the angular velocity sensor 2 of the present embodiment, since no foreign matter exists between the fixed member 6 and the base 3, the vibrator 4 attached to the fixed member 6 is moved with respect to the surface of the base 3. Since it can be held horizontally with high accuracy and the occurrence of unnecessary vibration in the vibrator 4 is suppressed, the angular velocity can be detected with high accuracy.

Further, according to the present embodiment, since the laser welding that generates less heat during the joining operation is used for joining the fixing member 6 and the base 3, the piezoelectric element constituting the vibrator 4 by the joining operation is used. Thus, the detection performance of the polarization and, consequently, the angular velocity can be prevented from deteriorating, and the reliability of the device can be improved.

Incidentally, in the angular velocity sensor 2, the unnecessary vibration generated in the vibrator 4 is affected not only by the fixed state of the fixing member 6 with respect to the base 3, but also by the bonding state of the vibrator 4 and the fixing member 6. Here, FIG.
What is the temperature drift width of the offset output of the detection signal caused by the unnecessary vibration when the bonding state between the “a” and the mounting surface 6a of the fixing member 6 (the application area and the application position of the adhesive) is changed. 6 is a graph showing the results of measuring the.

The temperature drift width means that the temperature is -30.
This is the width of change of the offset output when the temperature is changed to ８５85 ° C., and is shown by dividing by the output generated per unit angular velocity in FIG. Therefore, it is represented by an angle per unit time (° / s). The height H of the fixing member 6 used for the measurement was 5.3 m, as shown in FIG.
m, the thickness L is 2.1 mm, and the width W of the fixing portion 36 is 9.0 m.
m, the width SW of the connecting portion 32 is 4.4 mm, the height SH of the connecting portion 32 is 1.0 mm, and the height NH of the small diameter portion 34 is 1.0 m.
m, and the entire size of the vibrator 4 is 20.0 mm in height × 4.4 mm in width × 2.1 m in thickness.
m, and the size of the arm portions 12 and 14 is
It is 7.0 mm × width 2.0 × thickness 2.1 mm.

2 (a) to 2 (d) show the bottom surface 4a of the vibrator 4 or the mounting surface 6a of the fixing member 6 as viewed from the front, and the oblique lines indicate the portions where the adhesive is applied. Is represented. 2 (a) to 2 (d) correspond to the broken lines (a) to (d) in FIG. 3, that is, (a) is a case where the adhesive is applied to the base 3 side. , (B) show the case where the adhesive is applied to the side opposite to the base 3 side, and (c)
Shows a case where the adhesive is applied to one side in the longitudinal direction (Y-axis direction), and (d) shows a case where the adhesive is applied in a symmetric shape from the center.

As is clear from FIG. 3, if the adhesive is applied in a symmetrical shape with respect to the center (in the case of (d)) and the vibrator 4 and the fixing member 6 are bonded, the adhesive is Regardless of the application area, the temperature drift width can be sufficiently suppressed,
Also, as shown in (a) to (c), even when the adhesive is applied by being biased in any direction and bonded, if the applied area of the adhesive is 80% or more, the temperature drift width is sufficient. Can be suppressed.

That is, the bonding between the vibrator 4 and the fixing member 6 is as follows.
Needless to say, it is desirable to apply the adhesive uniformly over the entire surface of the adhesive surface. However, if the adhesive can be applied so as to satisfy the above conditions, it can be used without practical problems, and the manufacturing process can be simplified. it can. [Second Embodiment] Next, a second embodiment will be described.

The angular velocity sensor 42 of the present embodiment is partially different from the angular velocity sensor 2 of the first embodiment in the configuration of the fixing member, and the position at which laser welding is performed when the fixing member is fixed to the base. Only the difference is that the other configurations are completely the same. Therefore, only the different portions will be described.

FIG. 4A shows the angular velocity sensor 4 of this embodiment.
2 is a plan view, and FIG. In FIG. 4, for simplicity, various electrodes of the vibrator 4 and
Although the terminals T1 to T8 of the base 3 and the like are partially omitted, the base 3 and the vibrator 4 are completely the same as those in the first embodiment, and are also used in FIGS. 5 to 11 described below. It is exactly the same.

Then, the fixing member 46 in this embodiment is used.
Are connected portions, small-diameter portions, and the like as in the fixing member 6 of the first embodiment.
It has the same configuration as the fixing member 6 in the first embodiment, except that the fixing member 6 includes a fixing portion and a hole 48 is formed in the fixing portion. The holes 48 are formed one on each side of the extension of the small diameter portion.

In the fixing member 46 configured as described above,
As in the first embodiment, laser welding is performed in a state in which the fixing surface is directly adhered to the base 3. However, unlike the first embodiment in which laser welding is performed on the side surface of the fixing portion 36, By drilling a hole 48 in the fixing member 46, laser welding (welded portion S) is performed at a thin portion formed at the bottom of the hole 48.

Therefore, according to this embodiment, even if the metal oxide is scattered by the laser irradiation during welding, the metal oxide is scattered to the outside only by adhering to the inner wall surface of the hole 48 to contaminate the base 3 and the like. Because there is no, you can keep the appearance beautiful,
For example, even when a cover for protecting the vibrator 4 is attached to the base 3 by projection welding or the like, the cover can be securely attached because the surface of the base 3 is not dirty. Third Embodiment Next, a third embodiment will be described.

The angular velocity sensor 52 of this embodiment is different from the angular velocity sensor 2 of the first embodiment only in the configuration of the fixing member, and the other configurations are completely the same. I do. FIG. 5A is a plan view of the angular velocity sensor 52 of the present embodiment, FIG. 5B is a left side view thereof, and FIG. 5C is a BB sectional view thereof.

As shown in FIG. 5, the fixing member 56 in this embodiment comprises a connecting portion, a small-diameter portion, and a fixing portion, similarly to the fixing member 6 in the first embodiment. The side surfaces 56a, 56b of the fixing portion along the side surfaces 56a, 56b
The configuration is exactly the same as that of the fixing member 6 in the first embodiment, except that the width between 56b is chamfered so as to form a slope that becomes wider as the distance from the base 3 increases.

The fixing member 56 is fixed to the base 3 by subjecting the chamfered side surfaces 56a and 56b to laser welding (welding site S). According to the angular velocity sensor 52 of the present embodiment configured as described above, even if the metal oxide scatters due to the laser irradiation during welding, most of the metal oxide adheres to the chamfered side surfaces 56a and 56b and scatters around. Therefore, the same effect as in the second embodiment can be obtained. [Fourth Embodiment] Next, a fourth embodiment will be described.

The angular velocity sensor 62 of the present embodiment differs from the angular velocity sensor 2 of the first embodiment only in the configuration of the fixing member and the other configurations are completely the same. I do. 6A is a plan view of the angular velocity sensor 62 of the present embodiment, FIG. 6B is a left side view thereof, and FIG. 6C is a sectional view taken along line CC of FIG.

As shown in FIG. 6, the fixing member 66 in this embodiment comprises a connecting portion, a small diameter portion, and a fixing portion, similarly to the fixing member 6 in the first embodiment, and extends in the longitudinal direction of the vibrator 4. Except for the thin portions 66a and 66b, which are thinner than the central portion, are formed at both end portions of the fixed portion along the length.
It has exactly the same configuration as the fixing member 6 in the first embodiment.

Then, the fixing member 66 is
In steps a and 66b, the surface facing the base 3 is fixed to the base 3 by projection welding or laser welding (a welding part is not shown) of the same part as in the first and second embodiments. ing. In the angular velocity sensor 62 of the present embodiment configured as described above, the thin portion 66 having a small volume per area is provided.
a, 66b, the thin portion 66 is welded.
A small amount of heat escapes to the fixing member 66 on which the a and 66b are formed, and welding with small power becomes possible.

Therefore, according to the present embodiment, the fixing member 66
, The amount of heat transmitted to the vibrator 4 is small, and the deterioration of the polarization of the vibrator 4 due to thermal damage during welding is reduced, so that the angular velocity sensor 62 with good detection accuracy can be realized. [Fifth Embodiment] Next, a fifth embodiment will be described.

The angular velocity sensor 72 of this embodiment is different from the angular velocity sensor 2 of the first embodiment only in that the configuration of the base is partially different, and only in the manner of attaching the fixing member to the base. Since the configuration is completely the same, only this different portion will be described. 7A is a plan view of the angular velocity sensor 72 according to the present embodiment, FIG. 7B is a sectional view taken along the line DD, and FIG. 7C is a front view thereof.

As shown in FIG. 7, the base 73 in the present embodiment is formed in a simple flat plate shape without the concave portion 3a formed in the base 3 in the first embodiment. Further, a spacer 77 made of a metal material having a relatively small coefficient of thermal expansion and keeping the opposing surfaces thereof in parallel is interposed between the fixing portion of the fixing member 6 and the base 73. The fixing member 6 is fixed to the base 73 by melting the peripheral portion of the fixing member 6 (and the spacer 77) by laser welding (welding site S).

In the angular velocity sensor 72 according to the present embodiment having the above-described configuration, the vibrator 4 is suspended from the base 73 by the thickness of the spacer 77, so that the vibration of the vibrator 4 is hindered. It is not necessary to form a concave portion in the base 73 in order to prevent such a situation, and the configuration of the base 73 can be simplified.

Further, since the spacer 77 does not melt like a brazing material, when welding is performed, it is only necessary to press the base 73, the spacer 77, and the fixing member 6 so that the contact surfaces thereof come into close contact with each other. The base 73 of the fixing member 6 with respect to the base 73
Can be held horizontally easily and accurately. That is, according to the present embodiment, the vibrator 4 fixed to the fixing member 6 can be accurately held horizontally with respect to the base 73, so that unnecessary vibration for detection can be prevented. , Detection accuracy can be improved.

In the present embodiment, welding is performed with the spacer 77 interposed between the base 73 and the fixing member 6. However, as shown in FIG. Welding may be performed without interposing 77. FIG.
(A) is a top view of the angular velocity sensor 72a of this modification,
FIG. 8B is a sectional view taken along the line EE, and FIG. 8C is a front view thereof.

In this case, to perform the welding, first, the base 7
A jig in the form of a spacer 77 is formed between the vibrator 3 and the vibrator 4 to form a gap between them and hold them in parallel, and is positioned. In this state, the peripheral portion of the fixing member 6 is laser-welded. After melting and fixing the fixing member 6 to the base 73, the jig may be removed. Even in this case, similarly to the above-described angular velocity sensor 72, the vibrator 4 can be accurately held horizontally with respect to the base 73, and the same effect can be obtained.

The vibrator 4 only needs to be floated so as not to contact the base 73 during vibration. Therefore, the gap between the fixing member 6 (ie, the vibrator 4) and the base 73 is several mm. Since it is sufficient, even if the fixing member 6 is not in direct contact with the base 73, sufficient strength can be obtained only by the melted material by laser welding. [Sixth Embodiment] Next, a sixth embodiment will be described.

The angular velocity sensor 82 of this embodiment is different from the angular velocity sensor 2 of the first embodiment only in that the configuration of the base is partially different, and only in the manner of attaching the fixing member to the base. Since the configuration is completely the same, only this different portion will be described. 9A is a plan view of the angular velocity sensor 82 according to the present embodiment, FIG. 9B is a cross-sectional view taken along the line FF, and FIG. 9C is a front view thereof.

As shown in FIG. 9, the base 83 in the present embodiment does not have the concave portion 3a formed in the base 3 of the first embodiment, and instead has the fixing member 6 at the mounting position of the fixing member 6. 6
Are formed with two protruding portions 83a and 83b that can support each other so that their opposing surfaces are parallel to each other. Then, the fixing member 6 is fixed to the base 3 by projection welding of a portion that comes into contact with the protruding portions 83a and 83b, or laser welding of a peripheral side surface of the contact portion (a welding portion is not shown). I have.

In the angular velocity sensor 82 according to the present embodiment having the above-described structure, welding is performed at the projections 83a and 83b having a small volume, so that heat is applied to the base 83 on which the projections 83a and 83b are formed. And the welding with a small power becomes possible. Therefore, according to the present embodiment,
As in the fourth embodiment, the angular velocity sensor 8 with good detection accuracy
2 can be realized.

Further, in the angular velocity sensor 82 of this embodiment,
The vibrator 4 is supported on the base 8 by the height of the protrusions 83a and 83b.
3, it is not necessary to form a recess in the base 83 to prevent the vibration of the vibrator 4 from being hindered. Furthermore, in the angular velocity sensor 82 of the present embodiment, when welding is performed, the fixing member 6 is simply pressed against the protruding portion 83a so as to be in close contact with the base 83, so that the fixing member 6
The surface facing the base 83 can be horizontally held simply and accurately. That is, according to the present embodiment, the vibrator 4 fixed to the fixing member 6 can be accurately and horizontally held with respect to the base 83, so that unnecessary vibration for detection can be prevented. , Detection accuracy can be improved.

In the present embodiment, the base 83 is provided with the protruding portions 83a and 83b. However, as shown in FIG. 10, the fixing member 86 may be provided with the protruding portions 86a and 86b. Even with this configuration, the same effect as that of the above-described angular velocity sensor 82 can be obtained. FIG.
0 (a) is a plan view of the angular velocity sensor 82a of this modified example, FIG. 10 (b) is a GG sectional view thereof, and FIG. 10 (c).
Is a front view thereof.

Further, the protruding portion includes the base 83 and the fixing member 8.
6 may be provided instead of one of them. Seventh Embodiment Next, a seventh embodiment will be described.

The angular velocity sensor 92 of the present embodiment differs from the angular velocity sensor 2 of the first embodiment only in that the configuration of the base is partially different, and only in the manner of attaching the fixing member to the base. Since the configuration is completely the same, only this different portion will be described. FIG. 11A is a plan view of the angular velocity sensor 92 of the present embodiment, FIG. 11B is a left side view thereof, and FIG. 11C is a sectional view taken along line HH.

As shown in FIG. 11, the base 93 in the present embodiment does not have the concave portion 3a formed in the base 3 of the first embodiment, but is instead opposed to and parallel to the base 93. A holder 95 having a mounting surface 95a is provided. The holder 95 is formed by pressing a metal plate and formed. Both ends of the holder 95 are joined to the base 93 by laser welding or projection welding (welding portions are not shown). The fixing member 6 is joined to the base member 95a by laser welding or projection welding (the welding site is not shown).

In the angular velocity sensor 92 according to the present embodiment having the above-described structure, the welding is performed by the thin holder 95 made of a metal plate provided on the base 93, so that the fixing member 6 is fixed.
When welding is performed, there is little escape of heat to the base 93 connected via the holder 95, and welding with a small power becomes possible.

Therefore, according to the present embodiment, the amount of heat transmitted to the vibrator 4 via the fixing member 6 is small, and the deterioration of the polarization of the vibrator 4 due to thermal damage during welding is reduced. An angular velocity sensor 92 with good detection accuracy can be realized.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating an entire configuration of an angular velocity sensor according to a first embodiment.

FIG. 2 is an explanatory diagram showing conditions of an experiment whose results are shown in the graph of FIG.

FIG. 3 is a graph showing a result obtained by experimentally obtaining a relationship between a bonding state between a vibrator and a fixed member and a temperature drift width of an offset output.

FIG. 4 is an explanatory diagram illustrating a schematic configuration of an angular velocity sensor according to a second embodiment.

FIG. 5 is an explanatory diagram illustrating a schematic configuration of an angular velocity sensor according to a third embodiment.

FIG. 6 is an explanatory diagram illustrating a schematic configuration of an angular velocity sensor according to a fourth embodiment.

FIG. 7 is an explanatory diagram illustrating a schematic configuration of an angular velocity sensor according to a fifth embodiment.

FIG. 8 is an explanatory diagram showing a schematic configuration of a modification of the fifth embodiment.

FIG. 9 is an explanatory diagram illustrating a schematic configuration of an angular velocity sensor according to a sixth embodiment.

FIG. 10 is an explanatory diagram showing a schematic configuration of a modification of the sixth embodiment.

FIG. 11 is an explanatory diagram illustrating a schematic configuration of an angular velocity sensor according to a seventh embodiment.

[Explanation of symbols]

2, 42, 52, 62, 72, 72a, 82, 82a,
92: angular velocity sensor 3, 73, 83, 93: base 3a: recess 4
... vibrator 6, 46, 56, 66, 86 ... fixing member 6a ... mounting surface 6b ... fixing surface 10 ... base 12,1
4 Arm section 16, 18 Drive electrode 20 Monitor electrode 22
Virtual GND electrode 24 ... Processing electrode 25, 31 ... Short circuit electrode 26 ...
Detection electrode 27 ... Pad electrode 28 ... Extraction electrode 32 ...
Connection part 34 ... Small diameter part 36 ... Fixed part 48 ...
Hole 77: Spacer 95: Holder T1 to T8: Terminal W1 to W8: Wire
S: welded area

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tomoyuki Kanda 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Corporation (72) Inventor Katsuhide Akimoto 1-1-1, Showa-cho, Kariya City, Aichi Prefecture Denso Corporation Inside

Claims (12)

[Claims] 1. A base attached to an object to be measured which receives an angular velocity around a predetermined axis from the outside, a vibrator made of a piezoelectric body alone, and an end serving as a fulcrum of vibration of the vibrator fixed to the base. A vibrating element is excited in a direction orthogonal to the predetermined axis, and a vibration state in the excitation direction and a direction orthogonal to the predetermined axis is detected. In an angular velocity sensor that detects an angular velocity received by a measurement object, the fixing member is welded to the base while a surface facing the base is held in contact with or parallel to the base. An angular velocity sensor characterized in that: 2. The angular velocity sensor according to claim 1, wherein the fixing member is welded to the base at least on both side surfaces of the vibrator facing the excitation direction. 3. The fixing member according to claim 1, wherein both side portions are chamfered so that a width between both side portions to be welded to the base increases as the distance from the surface facing the base increases. The angular velocity sensor according to claim 2, wherein: 4. A spacer having a thickness greater than a vibration amplitude of the vibrator in the direction of the base is inserted between the base and the fixing member. Or the angular velocity sensor according to claim 3. 5. A thin portion having a reduced thickness is provided on at least one of the base and the fixing member, and the base and the fixing member are welded at the thin portion. The angular velocity sensor according to claim 1, wherein: 6. The fixing member according to claim 5, wherein the thin portion is formed at a bottom of the hole by forming a hole toward a surface facing the base. An angular velocity sensor as described. 7. A projection for abutting on at least one of the base and the fixing member so as to form a gap between the opposing surfaces and positioning the two opposing surfaces. The angular velocity sensor according to claim 1, wherein the base and the fixing member are welded at the projecting portion. 8. The angular velocity sensor according to claim 1, wherein welding for joining the fixing member to the base is laser welding for forming a local joint. . 9. The angular velocity sensor according to claim 1, wherein welding for joining the fixing member to the base is projection welding for forming a local joining portion. . 10. The fixing member according to claim 1, wherein a width along the excitation direction is larger on a surface facing the base than a mounting surface on which a fixed end of the vibrator is mounted.
An angular velocity sensor according to claim 9. 11. The fixed end of the vibrator and the mounting surface of the fixing member are adhered by an adhesive, and the adhesive is distributed in a symmetric shape with respect to the center of the fixed end and the mounting surface. The angular velocity sensor according to claim 1, wherein the angular velocity sensor is applied in such a manner. 12. The fixed end of the vibrator and the mounting surface of the fixing member are adhered with an adhesive, and the adhesive is applied to at least 80% of the area of the fixed end and the mounting surface. The angular velocity sensor according to any one of claims 1 to 11, wherein: