JP2002257551A - Vibration gyro - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration gyro capable of preventing decline of function against a drop impact, and operating normally even if a collision roll-over accident of a vehicle is generated during the loaded time on the vehicle. SOLUTION: This vibration gyro includes an oscillator 12. The oscillator 12 is supported by a support member 20. The support member 20 is fixed by a fixing member 30. The interval between the oscillator 12 and a projection part 32 of the fixing member 30 is set as the interval having the length with which the oscillator 12 and the fixing member 30 do not mechanically interfere with each other when an impact generated during the loaded time on the vehicle is applied thereto, though the oscillator 12 and the fixing member 30 interfere mechanically with each other when the drop impact is applied thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrating gyroscope, and more particularly to a vehicular vibrating gyroscope used for a vehicle rollover detection system, for example.

[0002]

2. Description of the Related Art Vibratory gyros for use in vehicles are required to have higher reliability than vibration gyros for consumer use, for example, for detecting camera shake. Specifically, in-vehicle gyros such as a gyro for a navigation system and a yaw rate sensor for vehicle control are required to satisfy the characteristic specifications even after a drop impact is applied. In order to respond to such demands, the vibrating gyroscope is provided with a braking member such as a stopper around the vibrator to prevent excessive mechanical displacement of the vibrator when a drop impact is applied. A structure that prevents deformation and destruction of a supporting member that supports and suspends a vibrator has been widely adopted. For example, Japanese Patent Application Laid-Open No. Hei 8-159779 discloses 3
A vibrating gyroscope in which a stopper is provided around a vibrator of a prismatic sound piece type is disclosed. In addition, Japanese Patent Application Laid-Open No.
No. 55 discloses a vibrating gyroscope in which a stopper is provided around a vibrator of a quadrangular prism-shaped sound element type. In such a conventional technique, the stopper prevents the displacement generated in the vibrator due to the impact applied to the vibrating gyroscope from exceeding the elastic limit of the support member supporting the vibrator. This prevents the gyro characteristics such as the sensitivity and the offset output value from being excessively and permanently changed as a result of the permanent deformation of the support member. In this case, if the stopper and the vibrator interfere with each other when an impact is applied, the mechanical vibration of the vibrator is restricted, and as a result, the gyro function is stopped during this time.

[0003]

On the other hand, as a new use of a vibration gyro for use in a vehicle, application to a vehicle rollover detection system is being studied. This system detects a rollover of a vehicle that occurs in the event of a vehicle accident. For example, it is necessary to detect a rollover that occurs following a vehicle collision.
That is, the vibration gyro is required to detect the next rollover without stopping the gyro function in response to the impact acceleration generated at the time of the vehicle collision. In such applications, it is important that the vibrating gyroscope operates normally even in the event of a collision, and the vibrator and the stopper around the vibrator do not mechanically interfere with an impact acceleration of, for example, 300 g for 5 ms. Is required. However, the conventional vibrating gyroscope has a structure in which a stopper prevents mechanical displacement of the vibrator with respect to an apparently excessive shock such as a drop shock, but the distance between the vibrator and the stopper is reduced. However, no design has been made to ensure the operation function for a specific range of impact acceleration by defining the following. Therefore, in order to realize a structure that can prevent the gyro function from stopping due to interference between the vibrator and the stopper when the vehicle rolls over, the conventional vibratory gyroscope requires many trial productions and experiments to repeat. It was necessary to find the optimum value of the gap between the stopper and the stopper.

[0004] Therefore, a main object of the present invention is to provide a vibration gyro capable of preventing a decrease in the function against a drop impact and capable of operating normally even when a collision and rollover accident occurs in a vehicle when mounted on an actual vehicle. That is.

[0005]

According to a vibration gyro according to the present invention, a drop impact is applied to a vibration gyro including a vibrator, a supporting member for supporting the vibrator, and a fixing member for fixing the supporting member. In this case, the vibrator and the fixed member mechanically interfere with each other, but when an impact generated when mounted on an actual vehicle is applied, a gap having a length that does not cause mechanical interference between the vibrator and the fixed member is formed between the vibrator and the fixed member. A vibrating gyroscope, which is provided between the vibrating gyroscope and a fixing member. In this vibrating gyroscope, the fixing member may include an elastic member that mechanically interferes with the vibrator when a drop impact is applied. further,
In the vibrating gyroscope according to the present invention, the vibrating gyroscope includes a circuit board having a circuit connected to the vibrator, a vibrator, a support member, a fixing member, and a housing in which the circuit board is housed. The gap between the vibrator and the circuit board is long enough that the vibrator and the circuit board do not mechanically interfere with each other when an impact generated when the vibrator and the circuit board are mounted on an actual vehicle is applied. And may be provided between them. In this vibrating gyroscope, the circuit board may include an elastic member that mechanically interferes with the vibrator when a drop impact is applied.
Further, a vibrating gyroscope according to the present invention includes a vibrator, a supporting member for supporting the vibrator, a fixing member for fixing the supporting member, and a housing, wherein the vibrator, the supporting member, and the fixing member are provided in the housing. In a vibrating gyroscope to be stored, the vibrator and the housing mechanically interfere when a drop impact is applied, but the vibrator and the housing are mechanically A vibratory gyroscope characterized by having a gap between the vibrator and the housing having a length that does not cause any interference. In this vibrating gyroscope, the housing may include an elastic member that mechanically interferes with the vibrator when a drop impact is applied. In the vibrating gyroscope according to the present invention, the circuit board may also serve as at least a part of the housing. Also,
In the vibrating gyroscope according to the present invention, the fixing member may also serve as at least a part of the housing. Further, in the vibrating gyroscope according to the present invention, the above-mentioned gap is d (m),
The mass of the vibrator is m (kg), and the spring constant of the support member in the same direction as the gap d (m) is k (kg / sec ² ).
Then, the gap d (m) is given by (m × 9.8 × 10 ³ ) / k <d <(m × 4.9 × 10
⁴ ) / k is preferably in the range.

In the vibrating gyroscope according to the present invention, when a drop impact is applied, the vibrator mechanically interferes with the fixed member, the circuit board, or the housing. It functions as a control member for preventing a decrease in function. Furthermore, in the vibrating gyroscope according to the present invention, when an impact generated when the vehicle is mounted on an actual vehicle is applied, the vibrator does not mechanically interfere with the fixed member, the circuit board, and the housing. Can operate normally even if the error occurs. In the vibrating gyroscope according to the present invention, the gap between the vibrator and the fixing member, the circuit board or the housing is d (m), and the mass of the vibrator is m (kg).
When the spring constant of the support member in the same direction as the gap d (m) is k (kg / sec ² ), the gap d
(M) is (m × 9.8 × 10 ³ ) / k <d <(m × 4.9 × 10
⁴ ) When it is in the range of / k, when a drop impact of 5000 g or more is applied, the vibrator mechanically interferes with the fixed member, the circuit board or the housing, and the function of the drop impact The reduction is prevented, and the 1000
g or less, when the vibrator is a fixed member,
Even if a collision and rollover accident occurs in the vehicle when mounted on an actual vehicle, the vehicle can operate normally without mechanical interference with the circuit board and the housing. Further, in this case, the gap between the vibrator and the fixing member, the circuit board or the housing can be easily determined from the above range, so that the vibrating gyroscope can be easily obtained.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments of the present invention with reference to the accompanying drawings.

[0008]

FIG. 1 is an exploded perspective view showing an example of a vibrating gyroscope according to the present invention, and FIG. 2 is a schematic plan view showing a main part of the vibrating gyroscope. The vibrating gyroscope 10 shown in FIG. 1 includes a vibrator 12 having, for example, a quadrangular prism shape. The vibrator 12 includes a vibrator in which two piezoelectric substrates made of piezoelectric ceramics are vertically adhered, and electrodes are formed on upper and lower surfaces of the vibrator. This vibrator 12
When a driving signal such as a sine wave signal is applied to the driving signal, two signals slightly inside from both ends in the longitudinal direction are applied.
The two parts are bent and vibrated as two node parts, and a detection signal corresponding to the angular velocity is generated by the Coriolis force.

On the upper surface and the lower surface of the vibrator 12, linear central portions 22 of four support members 20 are attached at four positions corresponding to two node portions. Thus, the vibrator 12 is sandwiched and supported by the four support members 20 from above and below. Further, the central portion 22 of these support members 20 is connected to the electrodes of the vibrator 12. Accordingly, these support members 20 serve as a conductive line for supplying a drive signal to the vibrator 12 and obtaining a detection signal from the vibrator 12. On both sides of the central portion 22 of the support member 20, a linear end portion 26 is provided via a substantially Z-shaped intermediate portion 24 for obtaining a vibration confinement effect of the vibrator 12.
Is formed. These support members 20 are formed of a constant elastic metal such as phosphor bronze, for example.

[0010] Both ends 26 of the four support members 20 are
For example, it is fixed to a rectangular frame-shaped fixing member 30 made of a synthetic resin. The fixing member 30 is arranged so as to surround the vibrator 12. The fixed member 30 is formed such that six block-shaped protrusions 32 are arranged on both sides of one end, the center and the other end in the longitudinal direction of the vibrator 12. Although not shown, the end 26 of the support member 20 penetrates through the fixing member 30 and is connected to a circuit board 4 to be described later.
0 circuit.

A circuit board 40 is mounted on the fixing member 30. On the circuit board 40, circuits such as a drive circuit for generating a drive signal for driving the vibrator 12 and a detection circuit for detecting an angular velocity from a detection signal of the vibrator 12 are mounted. The end 26 of the support member 20 is connected to the circuit of the circuit board 40.

The fixing member 30 is fixed via a cushion member 54 on a metal base 52 of a hermetic case 50 as a housing. Four terminals 56 penetrate and are attached to the base 52. These terminals 56
It penetrates the circuit board 40 and is connected to the circuit on the circuit board 40. Further, a metal cap 58 of the hermetic case 50 is mounted on the base 52 so as to cover the circuit board 40, the fixing member 30, the vibrator 12, and the like.

In the vibrating gyroscope 10, a gap is provided between the vibrator 12 and the fixed member 30. This gap is determined based on the following design criteria. In the actual design, the dimensions of the gap existing in the X-axis direction, the Y-axis direction, and the Z-axis direction with respect to the vibrator 12 are determined. The setting of the gap will be described in detail.

In the vibrating gyroscope 10, the vibrator 12
Weight is 0.15 × 10^-3(Kg). In addition,
In the vibrating gyroscope 10, the supporting portion for supporting the vibrator 12 is provided.
The spring constant of the material 20 in the Y-axis direction is 2 × 10^Four (K
g / sec^Two ). The spring constant referred to here is
A total of four supports passed between the moving element 12 and the fixing member 30
This is the sum of the spring constants of the holding member 20. In addition, this vibration
In Iro10, when falling from 1m on concrete,
An impact acceleration of approximately 5000 g is applied to the vibrator 12.
A vehicle on which the vibrating gyroscope 10 is mounted can collide with another vehicle.
When it collides, the impact acceleration of about 1000 g
12 is applied. The impact that occurs on the vehicle during a collision
The acceleration depends on the collision speed and the vehicle structure.
Here, 1000 g was adopted as a representative value.
The characteristic of the vehicle on which the vibration gyro 10 is mounted
Acceleration and vibration gyro 10 are used according to
To adopt the impact acceleration according to the characteristics of the system
Become. The vibrating gyroscope 10 vibrates even at the time of a vehicle collision.
The vibrator does not interfere with the vibrator 12 and the fixing member 30 when dropped.
12 and the fixing member 30 in order to satisfy the condition of interference
Is between the vibrator 12 and the fixed member 30 in the Y-axis direction.
Is defined as d (m), and the mass of the vibrator 12 is m (kg).
And the spring constants of the four support members 30 in the Y-axis direction
To k (kg / sec^Two ) And the impact acceleration at the time of vehicle collision is a
1 (m / sec^Two ), And the impact acceleration at the time of drop is a2 (m /
Second^Two ), The gap d is given by the following equation. (M × a1) / k <d <(m × a2) / k Impact acceleration 50 at the time of drop set as described above in this equation
00g (4.9 × 10 ^Four(M / sec^Two )) And in the event of a collision
Impact acceleration 1000 g (9.8 × 10^Three(M / sec^Two ))
When the value of is applied, the gap d becomes (m × 9.8 × 10^Three ) / K <d <(m × 4.9 × 10
^Four ) / K. And the quality of the vibrator 12 described above is
Apply the actual values of the quantity m and the spring constant k of the support member 30
Then, the gap d is 0.123 (mm) <d <0.61.
3 (mm). Based on this result, the support member 30
Elastic limit, workability during assembly processing and dimensional tolerance between parts
In consideration of the above, the vibrator 12, the support member 20, and the fixing member
Vibrator 12 and fixed part in Y-axis direction after assembly of 30
The gap d between the protruding portion 32 of the material 30 is, for example, 0.4
mm.

Therefore, in this vibration gyro 10,
When a drop impact is applied, excessive deformation is suppressed to prevent plastic deformation from occurring in the support member 20, and
When mounted on an actual vehicle, even if an impact acceleration due to a collision is applied, the vibrator 12 and the fixed member 30 do not interfere with each other, and as a result, it is possible to ensure the normal operation of the vibrating gyroscope.

Further, in the vibrating gyroscope 10, the gap between the vibrator 12 and the fixing member 30 can be easily determined from the above-mentioned range, so that it can be obtained easily.

As described above, for example, the reliability and function required of a vibration gyro mounted on a vehicle rollover detection system can be realized with less labor and time. Further, by setting the gap related to the vibrator according to the characteristics of the vehicle on which the vibrating gyroscope is mounted, a vibrating gyroscope with higher reliability can be realized.

In the above-mentioned vibrating gyroscope 10,
Regarding the gap between the oscillator 12 and the circuit board 30 or the base 52 of the hermetic case 50 in the X-axis direction,
The gap may be set similarly to the gap between the transducer 12 and the fixed member 30 in the Y-axis direction. When the gap in the X-axis direction is set in this way, the circuit board 30 and the hermetic case 50 can be used as a braking member for preventing the function from being deteriorated by a drop impact against displacement in the X-axis direction.

FIG. 3 is a schematic plan view showing a main part of another example of the vibrating gyroscope according to the present invention. In the vibrating gyroscope 10 shown in FIG. 3, the vibrating gyroscope 1 shown in FIGS.
Compared with 0, the protrusion 32 of the fixing member 30 is formed of an elastic member made of an elastic material such as rubber or silicone. In the present invention, in addition to the elastic member such as rubber or silicone, the elastic member has a shock absorbing function, such as a member formed of a spring structure such as a coil spring or a plate spring. Anything is acceptable. If the protrusion 32 of the fixing member 30 is formed of an elastic member as described above, it is possible to reduce the impact given to the vibrator 12 when the vibrator 12 and the fixing member 30 interfere with each other. For example, when the vibrator 12 is mainly made of a material having poor toughness such as ceramic, drop impact resistance is greatly improved by disposing such an elastic member. Further, by disposing the elastic member in such a manner, the kinetic energy generated in the vibrator 12 is gradually absorbed, and the stress applied to the joint between the vibrator 12 and the support member 20 is reduced. .

In the circuit board 40 and the hermetic case 50, a portion facing the vibrator 12 may be formed of an elastic member. By doing so, it is possible to reduce the impact given to the vibrator 12 when the vibrator 12 interferes with the circuit board 40 or the hermetic case 50.

FIG. 4 is an exploded perspective view showing still another example of the vibrating gyroscope according to the present invention. In the vibration gyro 10 shown in FIG. 4, the vibration gyro 1 shown in FIGS.
The circuit board 40 is attached below the fixing member 30 as compared with the case of FIG. A metal plate-shaped lid 60 is mounted on the fixing member 30. Further, a strip-shaped terminal 56 is attached to penetrate the fixing member 30.

Further, the vibration gyro 10 shown in FIG.
Similar to the vibrating gyroscope 10 shown in FIGS. 1 and 2, respective gaps between the vibrator 12 and the fixing member 30, the circuit board 40, and the lid 60 are set.

In the vibrating gyroscope 10 shown in FIG. 4, the fixing member 30, the circuit board 40, and the lid 60 also serve as part of the housing, respectively, as compared with the vibrating gyroscope 10 shown in FIG. Since the housing is constituted by the lid 60, another effect of being inexpensive and small is also achieved.

In each of the vibrating gyroscopes 10 described above, the quadrangular prism-shaped vibrator 12, the support member 20 having the substantially Z-shaped intermediate portion 22b, and the quadrangular frame-shaped fixing member 30 are used. In the invention, they may be formed in other shapes.

[0025]

According to the present invention, a vibrating gyroscope can be provided which can prevent the function from being deteriorated by a drop impact and can operate normally even when a collision and rollover accident occurs in the vehicle when mounted on an actual vehicle. Further, according to the present invention, it is possible to prevent a drop in function due to a drop impact and to easily obtain a vibration gyro that can normally operate even if a collision and rollover accident occurs in a vehicle when mounted on an actual vehicle.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an example of a vibrating gyroscope according to the present invention.

FIG. 2 is an illustrative plan view showing a main part of the vibrating gyroscope shown in FIG. 1;

FIG. 3 is an illustrative plan view showing a main part of another example of the vibrating gyroscope according to the present invention.

FIG. 4 is an exploded perspective view showing still another example of the vibrating gyroscope according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vibration gyroscope 12 Vibrator 20 Support member 30 Fixing member 40 Circuit board 50 Hermetic case 52 Base 54 Cushion material 56 Terminal 58 Cap 60 Cover

Continued on the front page (72) Inventor Takayuki Shimamoto 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto, Japan Inside Murata Manufacturing Co., Ltd. (72) Inventor Nobuyuki Ishidoko 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Murata Manufacturing, Ltd. F-term (reference) 2F105 AA02 BB12 CC06 CD13

Claims (9)

[The claims] In a vibrating gyroscope including a vibrator, a supporting member for supporting the vibrator, and a fixing member for fixing the supporting member, when a drop impact is applied, the vibrator and the fixing member are connected to each other. When a shock that mechanically interferes but is generated when mounted on a real vehicle is applied, a gap having a length that does not cause mechanical interference between the vibrator and the fixed member is provided between the vibrator and the fixed member. A vibrating gyroscope, comprising: 2. The fixing member includes an elastic member that mechanically interferes with the vibrator when a drop impact is applied,
The vibrating gyroscope according to claim 1. 3. A circuit board having a circuit connected to the vibrator, and a housing in which the vibrator, the support member, the fixing member, and the circuit board are housed, wherein a drop impact is applied. In the case where the vibrator and the circuit board mechanically interfere with each other, but a shock generated when mounted on an actual vehicle is applied, a gap having a length that does not cause mechanical interference between the vibrator and the circuit board is provided. The vibrating gyroscope according to claim 1, wherein the vibrating gyroscope is provided between the vibrator and the circuit board. 4. The circuit board includes an elastic member that mechanically interferes with the vibrator when a drop impact is applied,
The vibration gyro according to claim 3. 5. A vibrator, a support member for supporting the vibrator, a fixing member for fixing the support member, and a housing, wherein the vibrator, the support member, and the fixing member are housed in the housing. In a vibrating gyroscope, when a drop impact is applied, the vibrator and the housing mechanically interfere with each other. A vibrating gyroscope having a gap between the vibrator and the housing having a length that does not cause mechanical interference. 6. The vibrating gyroscope according to claim 5, wherein the housing includes an elastic member that mechanically interferes with the vibrator when a drop impact is applied. 7. The vibrating gyroscope according to claim 3, wherein the circuit board also serves as at least a part of the housing. 8. The vibrating gyroscope according to claim 3, wherein the fixing member also functions as at least a part of the housing. 9. The gap is d (m), the mass of the vibrator is m (kg), and the spring constant of the support member in the same direction as the gap d (m) is k (kg / sec ² ). Where, the gap d (m) is (m × 9.8 × 10 ³ ) / k <d <(m × 4.9 × 10
The vibrating gyroscope according to claim 1, wherein the vibrating gyroscope is in the range of ⁴ ) / k.