JPH0518760A - Vibrating gyro - Google Patents

Abstract

PURPOSE:To provide a vibrating gyro easily connected to external earth potential. CONSTITUTION:This vibrating gyro 10 includes a shielding cover 74 to become earth potential. This shielding cover 74 is formed of magnetic, conductive and elastic material such as iron, nickel or stainless material, and its center part is bent outward. A back cover 98 formed of conductive material such as aluminium is force-fitted to the shielding cover 74 against its elastic force. The back cover 98 is thereby connected electrically to the shielding cover 74.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration gyro,
In particular, it relates to a vibration gyro used in, for example, a navigation system mounted on an automobile.

[0002]

2. Description of the Related Art FIG. 9 is an illustrative view showing an example of a conventional vibrating gyro. The vibrating gyro 1 includes a vibrator 2.
The vibrator 2 includes a vibrator 3 having a triangular cross section, and piezoelectric elements 4a, 4b and 4c are formed on three side surfaces of the vibrator 3, respectively.

Further, one piezoelectric element 4c of the vibrator 2
Is electrically connected to the input end of the oscillation circuit 5, and the output end of the oscillation circuit 5 is electrically connected to the other two piezoelectric elements 4a and 4b. Therefore, the vibrator 2 is self-excited. Further, the two piezoelectric elements 4a and 4b are electrically connected to the two input ends of the detection circuit 6 including, for example, a differential amplifier. Therefore, the output of the detection circuit 6 detects the rotational angular velocity of the vibration gyro 1.

[0004]

However, the conventional vibrating gyro has a problem that it is difficult to connect it to an external ground potential.

Therefore, a primary object of the present invention is to provide a vibrating gyro that is easy to connect to an external ground potential.

[0006]

SUMMARY OF THE INVENTION The present invention includes a shield cover having a ground potential and a back cover electrically connected to the shield cover, and at least one of the shield cover and the back cover is made of an elastic material. The vibrating gyro is formed and the back cover is pressure-bonded to the shield cover against the elastic force.

[0007]

The shield cover and the back cover are electrically connected to each other by crimping the back cover onto the shield cover, which has the ground potential.

[0008]

According to the present invention, since the back cover is electrically connected to the shield cover having the ground potential, it is possible to obtain the vibration gyro which is easily connected to the external ground potential. Further, in the vibrating gyroscope according to the present invention,
The back cover can be electrically connected to the shield cover simply by simply crimping the back cover to the shield cover.

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

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 (A) is a front view solution view showing an embodiment of the present invention, and FIG. 1 (B) is a side view solution view thereof. FIG. 2 is an exploded perspective view of the vibrating gyro shown in FIG. Figure 3
FIG. 3 is a circuit diagram of the vibration gyro shown in FIG. 1. 4 is shown in FIG.
FIG. 3 is an exploded perspective view showing a main part of the vibration gyro shown in FIG.

The vibrating gyro 10 includes a vibrator 12. The vibrator 12 includes, for example, as shown in FIG. 4, a vibrator 14 having a triangular cross section, for example. The vibrating body 14 is formed of a constant elastic metal material such as nickel, iron, chromium, titanium, or an alloy thereof such as elinvar or an iron-nickel alloy. The vibrating body 14 may be made of a material other than metal that generally causes mechanical vibration, such as quartz, glass, crystal, or ceramic.

As shown in FIG.
Piezoelectric elements 16a, 16b and 16c are respectively fixed to the centers of the three side surfaces. These piezoelectric elements 16
Each of a to 16c includes a piezoelectric layer 18 made of, for example, ceramic, and electrodes 20 are provided on both main surfaces of the piezoelectric layer 18.
a and 20b are formed respectively. Then, the electrode 20a on one main surface of these piezoelectric elements 16a to 16c is
It is bonded to the side surface of the vibrating body 14 with a conductive adhesive, for example. In this embodiment, the two piezoelectric elements 16a and 16b are used for driving for vibrating or driving the vibrating body 14 and for detecting for detecting the displacement of the vibrating body 14, and the other one piezoelectric element. The element 16c is used for feedback for feeding back the drive signal to the two piezoelectric elements 16a and 16b.

The vibrator 12 is supported by two support members 22a and 22b, particularly as shown in FIG.
Each of the support members 22a and 22b is formed in a U shape by a wire material such as metal. The central portions of the support members 22a and 22b are the two piezoelectric elements 16
It is fixed to one ridgeline portion of the vibrating body 14 sandwiched between a and 16b. In this case, the support members 22a and 22b
Is fixed in the vicinity of the node point of the vibrating body 14 in order to prevent the vibration of the vibrating body 14 from being adversely affected. In this embodiment, assuming that the length of the vibrating body 14 is L, these support members 22a and 22b are fixed at positions of 0.224L from both ends of the vibrating body 14.

These support members 22a and 22b are
For example, when it is fixed to the vibrating body 14 by bonding with an adhesive, soldering, or welding, when it is fixed by soldering or welding,
Considering both the strength of the support member and the solderability or weldability of the support member to the vibrating body, for example, nickel, platinum, gold, silver, etc. are provided around a strong metal wire such as molybdenum or titanium. A wire rod coated with a material with good solderability and weldability such as copper, stainless steel, and iron.
It is preferable to form the support member.

Both end portions of these support members 22a and 22b are made of, for example, iron, as shown in FIGS.
It is fixed to, for example, substantially rectangular fixing plates 24a and 24b made of a metal material such as nickel or stainless steel. That is, two holes 26 are formed in each of the fixed plates 24a and 24b. Then, both end portions of the one support member 22a are attached to the two of the one fixing plate 24a.
The holes 26 are inserted and soldered. Similarly, both end portions of the other support member 22b are fixed to the other fixed plate 24b.
And is soldered.

At one end of each of the fixing plates 24a and 24b, a piece member 28 of, for example, a substantially U-shaped plate is formed so as not to come into contact with the vibrator 12. Further, for example, plate-shaped protection members 30 are formed at both ends of these piece members 28 in the width direction. These protection members 30 prevent the support members 22 a and 22 b from being displaced more than necessary in the width direction of the vibrator 12, and thus the support members 22 a and 22 b.
It is for protecting a and 22b, and is arranged in the vicinity of the support members 22a and 22b, for example, inside the support members 22a and 22b. In addition, these piece members 2
8 and the protection member 30 are integrally formed with the fixing plates 24a and 24b.

The fixing plates 24a and 24b are shown in FIG.
As shown in FIG. 4 and FIG.
By 2a and 32b, it is fixed to one main surface of a strip-shaped support plate 34 made of a material having magnetism and conductivity, such as iron, nickel, and stainless.

As shown in FIGS. 4 and 6, the support plate 34 is provided with foot members 36a and 36b extending downward from one end and the other end in the longitudinal direction. Further, one protrusion 38 is formed at the center of the lower end of the foot member 36a on one end side in the longitudinal direction of the support plate 34. Further, on both sides of the other end of the support plate 34 in the longitudinal direction, two protrusions 40 are provided.
a and 40b are formed. These protrusions 38, 4
Reference numerals 0a and 40b denote the circuit board 4 whose support plate 34 will be described later.
It is used for fixing to 6. Further, on the support plate 34, two holding pieces 42 are formed at one end in the width direction thereof at a predetermined interval, and two holding pieces 42 are also formed at the other end in the width direction thereof at a predetermined interval. To be done. These holding pieces 42 are used to hold the work cover 56 described later on the support plate 34.

At the center of one main surface of the support plate 34, a positive temperature coefficient thermistor 44 is attached, as shown in FIG. The positive temperature coefficient thermistor 44 is for keeping the temperature of the vibrator 12 stable. That is, a constant voltage is applied to the positive temperature coefficient thermistor 44. When the temperature of the vibrator 12, that is, the temperature around the positive temperature coefficient thermistor 44 is increased, the resistance of the positive temperature coefficient thermistor 44 is increased, and the amount of heat generated from the positive temperature coefficient thermistor 44 is decreased to lower the temperature of the surroundings. When the temperature becomes lower, the resistance of the positive temperature coefficient thermistor 44 becomes smaller, and the amount of heat generated therefrom increases, and the temperature around it rises. Therefore, the temperature of the vibrator 12 is kept stable by the PTC thermistor 44.

The support plate 34 is attached to one main surface side of the circuit board 46 as shown in FIGS. In this case, the protrusion 38 of the foot member 36a on one end side of the support plate 34
Is inserted into the circuit board 46 and soldered to a ground pattern (not shown) on the other main surface of the circuit board 46. Therefore, the support plate 34 has two foot members 36a and 36a.
In the state of being floated from one main surface of the circuit board 46 at b, it is fixed to the circuit board 46.

A sheet-shaped cushion material 48 is adhered to the center of the one main surface of the circuit board 46 between the support plate 34 and the circuit board 46 with an adhesive. The cushion material 48 is formed of a material in which rubber such as butyl rubber or synthetic resin such as urethane is foamed so as not to be connected to each other, that is, so-called independent foaming.

Further, on one main surface of the circuit board 46, a U-shaped relay board 50 is attached to the outside of the other end in the longitudinal direction of the support plate 34. The relay board 50 has three terminals 52a, 5 which are parallel to the main surface thereof and extend to the outside thereof.
2b and 52c are formed parallel to each other. Then, these terminals 52a to 52c are penetrated through the circuit board 46 and soldered to the three conductor patterns (not shown) on the other main surface of the circuit board 46, respectively. Therefore, the relay board 50 is arranged such that one main surface thereof faces the end surface of the support plate 34 on the other end side in the longitudinal direction.
It is fixed to 6.

The relay board 50 also includes a support plate 34.
Two protruding portions 40a and 40b are inserted, and these protruding portions 40a and 40b are soldered to a conductor pattern (not shown) on the other main surface of the relay substrate 50. Therefore, the support plate 34 is
It is further firmly fixed to the circuit board 46.

Furthermore, 3 is formed on the other main surface of the relay board 50.
Three conductor patterns 54a, 54b and 54c are formed, and three terminals 52a to 52c are electrically connected to these conductor patterns 54a to 54c, respectively. Further, the electrodes 20b on the other main surface of the three piezoelectric elements 16a to 16c of the vibrator 12 are electrically connected to the conductor patterns 54a to 54c by lead wires (not shown), respectively.

The support plate 34 is made of, for example, iron, nickel, or the like so as to cover the vibrator 12 and the relay substrate 50.
A work cover 56 made of a magnetic and conductive material such as stainless steel is attached. Work cover 5
As shown in FIGS. 4 and 7, 6 includes a strip-shaped main surface member 58, and the main surface member 58 is formed with side surface members 60 extending downward from both ends in the width direction thereof. The center portions of the lower ends of the side surface members 60 are each formed as a protruding portion 62 protruding outward. In addition, the main surface member 5
The protective member 64 having an L-shaped cross section, for example, is formed on both ends of the protective member 8 in the longitudinal direction. Then, in the work cover 56, those side members 60 are fitted inside the holding pieces 42 of the support plate 34, and the projecting portions 62 of the side members 60 are fitted between the holding pieces 42, 42. In this case, the two protective members 64 are arranged near the outer sides of both ends of the vibrator 12 in the longitudinal direction. These protective members 64
Prevents the vibrator 12 from displacing more than necessary in the longitudinal direction, that is, the support members 22a and 22b are
The purpose of this is to protect the support members 22a and 22b by preventing them from being displaced more than necessary in the longitudinal direction.

On the other hand, on the other main surface of the circuit board 46, as shown in FIG.
An oscillator circuit 66 and a detection circuit 68 are mounted as shown in FIG.

The oscillator circuit 66 is for driving or vibrating the vibrator 12, and includes a crystal for stabilizing the oscillation frequency and a phase correction circuit for adjusting the oscillation frequency. The input end of the oscillator circuit 66 has a conductor pattern (not shown) and a relay substrate 5 as shown in FIG.
The piezoelectric element 1 of the vibrator 12 via the terminal 52c of 0
6c is electrically connected to the electrode 20b, the output end of the oscillation circuit 66 is divided by the variable resistor 72a, and the piezoelectric element 16a is provided via another conductor pattern (not shown), terminals 52a and 52b, and the like. And 16b of electrodes 20b, respectively.

The detection circuit 68 is for detecting the displacement of the vibrator 12, and is composed of, for example, a differential amplifier. The two input ends of the detection circuit 68 are connected to the electrodes 20b of the piezoelectric elements 16a and 16b, respectively, via a conductor pattern (not shown) and terminals 52a and 52b.

Further, on the other main surface of the circuit board 46, as shown in FIG. 4, three variable resistors 72a, 72b and 72c are mounted. One variable resistor 72a balances the output of the oscillation circuit with the piezoelectric elements 16a and 16a.
b. In addition, another variable resistor 72b
Is for adjusting the level of the input signal input to the detection circuit 68, and is connected between two input terminals of the detection circuit 68 as shown in FIG. Further, the remaining variable resistor 72c is for adjusting the level of the output signal of the detection circuit 68, and is connected between the output end of the detection circuit 68 and the ground.

Further, on the other main surface of the circuit board 46, as shown in FIGS. 2 and 4, the oscillation circuit 66 and the detection circuit 6 are provided.
8 and the variable resistors 72a, 72b and 72c, etc., a shield cover 74 made of a material having magnetism, conductivity and elasticity, such as iron, nickel, and stainless, is attached. Shield cover 74
As shown in FIGS. 4 and 8, includes a rectangular plate-shaped main surface member 76 having substantially the same width as the circuit board 46. The central portion of the main surface member 76 in the width direction is bent outward. Side surface members 78a and 78b are formed at both ends in the width direction of the main surface member 76, respectively. Further, protrusions 80 are formed at both ends of the side members 78a and 78b, respectively. Then, the protrusions 80 are inserted into the circuit board 46 and soldered to the ground pattern (not shown) on the one main surface of the circuit board 46. Further, the shield cover 74 has a side member 78.
Three holes 84a, 84b and 84c corresponding to the adjusting screws of the three variable resistors 72a to 72c are formed in a.

On one main surface of the circuit board 46, a plurality of power supply terminals for supplying electric power to the positive temperature coefficient thermistor 44, the oscillation circuit 66 and the detection circuit 68 and output terminals for taking out an output signal of the detection circuit 68 are provided. Terminals 86 of the positive temperature coefficient thermistor 4 are formed upward, and these terminals 86 are provided via a conductor pattern (not shown) of the circuit board 46 or the like.
4, connected to the oscillation circuit 66 and the detection circuit 68.

The vibrator 12, the circuit board 46, the work cover 56, and the like are housed in a box-shaped case 92 together with two cushion members 88 and 90, as shown in FIGS. ..

The cushion material 88 is formed in a rectangular plate shape, for example, and is arranged on the upper surface of the work cover 56. Further, the cushion material 90 has a work cover 56 at the center thereof.
Is formed on the side surface of the work cover 56. These cushioning materials 88 and 90
Like the above-mentioned cushion material 48, is made of a material obtained by foaming rubber such as butyl rubber or synthetic resin such as urethane so as not to connect the bubbles. These cushion materials 48, 88 and 90 are used for the vibrator 1
The purpose of this is to enhance the heat insulating effect between the periphery of 2 and the outside, absorb unnecessary sound waves from the outside to the vibrator 12, and prevent leakage of vibration from the vibrator 12 to the outside.

In addition, an opening 94 is formed in the case 92 so as to correspond to the terminal 86. Particularly, as shown in FIG.
The terminal 86 is exposed through the opening 94. Further, as shown in FIG. 2, the case 92 includes a variable resistor 72.
corresponding to the adjusting screws a and 72c, two holes 96a and 96 for adjusting these adjusting screws from the outside.
b is formed.

As shown in FIGS. 1 and 2, a rectangular plate-shaped back cover 98 made of a conductor such as aluminum is attached to the case 92 with screws 100. In this case, since the center of the main surface member 76 of the elastic shield cover 74 in the width direction is bent outward, the back cover 98 is the shield cover 7.
It is crimped to the shield cover 74 against the elastic force of 4 and electrically connected to the shield cover 74.

In this vibrating gyro 10, since the protective member 30 is provided near the inside of the supporting members 22a and 22b for supporting the vibrator 12, the supporting member 22 is provided.
Since a and 22b are not displaced more than necessary in the width direction of the vibrator 12, plastic deformation is unlikely to occur. Therefore, deterioration of characteristics due to plastic deformation of the support members 22a and 22b is prevented. Further, the support members 22a and 22b are not displaced more than necessary in the longitudinal direction of the vibrator 12 by the protective members 64 of the work cover 56 provided near the outer sides of both ends of the vibrator 12 in the longitudinal direction.
It is possible to prevent deterioration of characteristics due to plastic deformation of 22 and 22b. In order to prevent the deterioration of the characteristics due to the plastic deformation of the support members 22a and 22b, the protective member is used as the vibrator 1.
2 or the supporting members 22a and 22b may be provided, and the shape of the protective member is not limited to a plate shape and may be a block shape.

Further, in this vibrating gyro 10, the cushion member 4 made of a material that is independently foamed around the vibrator 12 is provided.
8, 88 and 90 are provided, the vibrator 12
The heat insulating effect between the periphery of the vibrator and the outside is good, unnecessary sound waves from the outside to the vibrator 12 can be absorbed, and leakage of vibration from the vibrator 12 to the outside can be prevented. Therefore, it is possible to prevent characteristic deterioration due to external temperature changes and external sound waves, and to prevent leakage of vibration from the vibrator 12 to external devices.

Further, in the vibrating gyroscope 10, since the positive temperature coefficient thermistor 44 is provided near the vibrator 12, the temperature of the vibrator 12 can be kept stable. Therefore, deterioration of characteristics due to temperature change can be suppressed. In order to keep the temperature of the vibrator 12 stable, the vibrator 1
2 is provided with another heater such as a negative characteristic thermistor, a nichrome wire, or a ceramic heater in place of the positive characteristic thermistor 44, and a temperature of, for example, a bimetal for detecting the temperature around the vibrator 12. A detector may be provided to turn the heater on and off based on the detection by the temperature detector.

Further, in this vibrating gyroscope 10, since the support plate 34 and the work cover 56 are provided around the vibrator 12 as a shielding material made of a magnetic material, the vibrator 12 is magnetically shielded from the outside. Therefore, it is possible to prevent deterioration of characteristics due to external magnetism.

Further, in the vibrating gyroscope 10, the circuit board 46 is connected via the terminals 52a to 52c of the relay board 50.
The vibrator 12 provided on one main surface side is electrically connected to the oscillation circuit 66 and the detection circuit 68 on the other main surface side of the circuit board 46, so that from the one main surface side to the other main surface side of the circuit board 46. There is no need to route the lead wire to the side.

Further, in the vibrating gyroscope 10, since the shield cover 74 made of a magnetic material is provided so as to cover the oscillator circuit 66 and the like, high frequency noise generated from the oscillator circuit 66 can be prevented. it can.

Further, in this vibrating gyroscope 10, the back cover 98 is electrically connected to the shield cover 74 which is at the ground potential, so that it is easy to connect to the external ground potential. Further, the back cover 98 is electrically connected to the shield cover 74 simply by pressing the back cover 98 against the shield cover 74 against the elastic force of the shield cover 74. In this way, the shield cover 74 and the back cover 98
In order to easily and electrically connect to each other, at least one of the shield cover 74 and the back cover 98 is formed of an elastic material, and the back cover 98 is pressure-bonded to the shield cover 74 against the elastic force. You can do this.

Although the vibrating body 14 of the vibrator 12 is formed in a triangular cross section in the above-described embodiment, the vibrating body 14 is
May have a quadrangular cross section. In this case, the piezoelectric element may be formed on the four side surfaces of the vibrating body.

[Brief description of drawings]

FIG. 1A is a schematic front view showing an embodiment of the present invention, and FIG. 1B is a side schematic view thereof.

FIG. 2 is an exploded perspective view of the vibration gyro shown in FIG.

FIG. 3 is a circuit diagram of the vibration gyro shown in FIG.

FIG. 4 is an exploded perspective view showing a main part of the vibration gyro shown in FIG.

5A is a front view showing a structure for supporting a vibrator of the vibration gyro shown in FIG. 1, and FIG. 5B is a side view showing the structure.

6 (A) is a front view of a support plate used in the vibration gyro shown in FIG. 1, and FIG. 6 (B) is a plan view thereof.
(C) is the side view.

7A is a front view of a work cover used in the vibration gyro shown in FIG. 1, FIG. 7B is a plan view thereof, and FIG. 7C is a side view thereof.

8A is a front view of a shield cover used in the vibrating gyro shown in FIG. 1, FIG. 8B is a plan view thereof, and FIG. 8C is a side view thereof.

FIG. 9 is an illustrative view showing one example of a conventional vibrating gyro.

[Explanation of symbols]

 10 Vibration Gyro 12 Vibrator 46 Circuit Board 66 Oscillation Circuit 68 Detection Circuit 74 Shield Cover 98 Back Cover

Claims (1)

Claim: What is claimed is: 1. A shield cover having a ground potential, and a back cover electrically connected to the shield cover. At least one of the shield cover and the back cover is made of an elastic material. A vibrating gyro formed by pressing the back cover onto the shield cover against its elastic force.