JPH0721414B2 - Angular velocity sensor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a tuning fork vibration type angular velocity sensor.

2. Description of the Related Art Conventionally, there has been proposed a tuning fork vibrating angular velocity sensor that detects an angular velocity from Coriolis force that occurs when an angular velocity is generated by vibrating an object without using a rotational force (for example, Japanese Patent Laid-Open Publication No. Sho. 59-5542 publication).

A prototype of this structure can be found in US Pat. No. 2,544,646. According to this, a rectangular plate of a drive elastic body (for excitation) and a detection elastic body is joined linearly and orthogonally, and the Coriolis force acting on the detection elastic body having a speed is detected. It is a thing. A conventional angular velocity sensor will be described below with reference to the drawings.

FIG. 6 is a block diagram of a conventional angular velocity sensor. In FIG. 6, the driving piezoelectric bimorph element 2 and the driving detection piezoelectric bimorph element 3 (hereinafter, both are referred to as driving piezoelectric bimorph elements) and the detection piezoelectric bimorph elements 1a and 1b, which are the main components of the angular velocity sensor, are shown in FIG. , The adhesive 5 via the connecting member 4 so that the orthogonal accuracy is within ± 20 '.
Are orthogonally coupled by. Further, the rear ends of the driving piezoelectric bimorph elements 2 and 3 are connected to each other via a connecting member 6, and thus a tuning fork vibrating element is formed. The tuning fork vibrating element is erected on the base 7 by a metal member 8. The lead wires 9a, 9b, 9c, 9d from the detecting piezoelectric bimorph elements 1a, 1b are soldered to the electrodes on the front and back of the detecting piezoelectric bimorph elements 1a, 1b, and the driving piezoelectric bimorph element is used.
It is adhesively fixed to a few side surfaces and is connected to a lead pin 10 implanted in the base 7. The lead wires 9e and 9f from the driving piezoelectric bimorph elements 2 and 3 are also lead pins.
Connected to 10. Such strict orthogonal accuracy is required when the driving piezoelectric bimorph elements 2 and 3 vibrate as shown in FIG. 7 if the driving speed direction and the detection sensitivity direction are completely orthogonal to each other. When the angular velocity does not enter, the electric signals generated in the detection piezoelectric bimorph elements 1a and 1b are zero. However, as shown in FIG. 8, when the orthogonality is deviated, a driving inertia force proportional to the sine of the orthogonal error is applied to the detection piezoelectric bimorph elements 1a and 1b even if the angular velocity is not applied, In response to this, an electric signal (hereinafter referred to as a zero signal) is generated. Therefore, in order to improve the detection accuracy of the input angular velocity, strict assembly accuracy is required as described above.

Also, as shown in FIG. 6, the lead wires 9a, 9b, 9c, 9d
The reason why the bonding member 4 is adhered to the bonding member 4 is that the bonding member 4 portion has relatively little vibration, so that disconnection of the lead wire is less likely to occur, and at the same time, the zero signal is reduced. This is because. As shown in FIG. 9, from the detecting piezoelectric bimorph element 1a to the lead wire 9
When a and 9b are pulled out without being fixed by adhesion, if the tensions of the lead wires 9a and 9b are different between the front and back of the detection piezoelectric bimorph element 1a, a zero signal is generated. For this reason, the lead wire is bonded and fixed.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above-described conventional configuration, the wiring of the lead wire is complicated and takes a lot of man-hours, and the reliability of the adhesive for fixing the lead wire and the excessive adhesion are taken into consideration. There was a problem that it was necessary.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an angular velocity sensor capable of realizing simplification of wiring without adhering and fixing lead wires.

Means for Solving the Problems In order to achieve this object, an angular velocity sensor of the present invention is a sensor element constituted by a driving piezoelectric bimorph element and a detecting piezoelectric bimorph element which are coaxially orthogonally coupled to each other via a coupling member. And a lead wire electrically connected to the detection piezoelectric bimorph element of the sensor element, and a holding for holding the other end of the lead wire in a position symmetrical with respect to the surface of the detection piezoelectric bimorph element. It has a body.

Action With this configuration, the connecting position of the lead wire to the lead pin is fixed by the holding body, and the lead wiring can be simplified while maintaining the symmetry.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of an angular velocity sensor according to an embodiment of the present invention. In FIG. 1, the driving piezoelectric bimorph elements 12 and 13 and the detecting piezoelectric bimorph elements 11a and 11b are orthogonally coupled to each other via a coupling member 14 to form two sensor elements. A coupling member 15 is provided at the rear end of the driving piezoelectric bimorph elements 12 and 13.
The tuning fork vibrating element is configured by coupling via. The tuning fork vibrating element is supported by a metal elastic member 17 provided upright on the base 16 and disposed on the base 16. The base 16 also serves as a lid for closing the opening of a bottomed cylindrical case (not shown), and the tuning fork vibrating element is enclosed in the case. 18a, 18b, 18c, 18d, 18e, 18f are lead pins implanted in the base 16, and of these lead pins 18a to 18f, the lead pins 18a, 18b, 18c, 18d are longer than the other lead pins 18e, 18f. Is made of a long metal member, and a ring-shaped holding plate 19 made of a printed wiring board is fixed to the tip ends of the lead pins 18a, 18b, 18c, 18d of the tuning fork. The vibrating element is arranged so as to be spaced apart from the vibrating element by a predetermined distance and orthogonal to the tuning fork vibrating element.

20a ~ 20f is a lead wire having one end soldered to the electrodes of the detecting piezoelectric bimorph elements 11a, 11b and the driving piezoelectric bimorph elements 12, 13, the lead wire 20a pulled out from the detecting piezoelectric bimorph elements 11a, 11b, 20b, 20c, 20d
Is a lead pin 18 via a holding plate 19 at a position symmetrical with respect to the surfaces of the detection piezoelectric bimorph elements 11a and 11b.
Lead wires 20e, 20f connected to a, 18b, 18c, 18d, respectively, and pulled out from the driving piezoelectric bimorph elements 12, 13
Are connected to the lead pins 18e and 18f.

The ring-shaped holding plate 19 is provided with holes, projections, etc. for holding the lead wires 20a to 20d, whereby the lead wires 20a to 20d are held.
Hold the middle part of a-20d, and lead wires 20a-20d
You may connect the tip part of this and the lead pins 18a-18d directly. Also, the holding plate 19 allows the lead pins 18a, 18b, 18c, 18d
Since the ends of the wire have been positioned, the lead wires 20a to 20d may be directly connected thereto.

In this embodiment, the lead wires 20a to 20d have a diameter of 0.03 mm.
As shown in FIG. 2, five mm-strand urethane-coated annealed copper wires are bent in an inverted J shape so as to be located in a plane substantially perpendicular to the plane of the piezoelectric bimorph element for detection.

FIG. 3 shows the tension in each direction of the annealed copper wire bent in an inverted J shape. If the tension is large, the error due to manufacturing variation also increases accordingly, so the symmetry of the front and back of the piezoelectric bimorph element for detection is broken, and the zero signal becomes large, so as described in the section of the prior art,
The detection accuracy of the input angular velocity becomes poor. Further, when the tension is large, the fatigue of the end portion of the lead wire becomes large, and the risk of disconnection becomes large. Therefore, it can be seen that the pull-out angle is better as it approaches 90 ° so that the tension becomes smaller. Also, the reason why the lead wire is curved is to reduce the tension.

Also in this embodiment, the reason why the stranded wires are used for the lead wires 20a to 20d is to prevent breakage and wire breakage. Moreover, the risk of wire breakage increases when the lead wires 20a to 20d resonate. Therefore, the lead wires 20a to 20d
It is desirable that the natural frequency of (1) has a large difference from the natural frequency of the tuning fork vibrating element (about 1 KHz in this embodiment). If the natural frequencies of the lead wires 20a to 20d are lower than the natural frequency of the tuning fork vibrating element, the harmonics of the former may approach the natural vibration frequency of the latter tuning fork vibrator. Must have a higher natural frequency of the tuning fork oscillator than the latter. In the case of this embodiment, the natural frequencies of the lead wires 20a to 20d are 3 KHz or more, which is set to be twice or more that of the tuning fork vibrating element. When the diameter of the lead wire is increased and the number of twisted wires is increased, the natural frequency increases, but the tension also increases, resulting in a large zero signal. Alternatively, it inhibits the vibration of the tuning fork vibrating element. As shown in Fig. 4 and Fig. 5, in the case of φ0.03 urethane-coated annealed copper wire, up to 10 wires and in the case of more than 5 wires, the wire diameter is up to φ0.5. It is the range to be.

In the case of this embodiment, the natural frequencies of the lead pins 18a to 18d are
The frequency is 1.6 KHz, and if a product with a small wire diameter is produced due to manufacturing variations, it approaches the natural frequency of the tuning fork vibrating element. When both natural frequencies are close to each other, the latter vibration is transmitted to the former through the base, and when the former resonates, the former vibration is transmitted to the latter in reverse, and the latter detection piezoelectric bimorph elements 11a and 11b are vibrated. Therefore, the zero signal becomes large. Further, the risk of disconnection of the lead wires 20a to 20d becomes great. Therefore, the natural frequency is increased by connecting the four pins of the lead pins 18a to 18d with the holding plate 19. According to the calculation, the natural frequency of the holding body including the lead pin and the holding plate is 12 KHz which is more than twice the natural frequency of the tuning fork vibrating element. Also, by making the lead pins 18a-18d sufficiently thick and short,
Even without the holding plate 19, a holding body having a sufficiently high natural frequency can be used.

EFFECTS OF THE INVENTION As described above, according to the present invention, it is possible to realize the simplification of the wiring without fixing the lead wire, and it is possible to obtain the angular velocity sensor with high detection accuracy.

[Brief description of drawings]

FIG. 1 is a perspective view showing a part of an angular velocity sensor according to an embodiment of the present invention with a part cut away, FIG. 2 is a plan view showing a lead wire of the sensor, and FIG. 3 is a vibration direction dependence of tension of the lead wire. FIG. 4 is a characteristic diagram showing the dependence of the sensitivity of the angular velocity sensor of the present invention on the number of lines from the lead wire,
FIG. 5 is a characteristic diagram showing the dependency of the wire diameter from the lead wire, FIG. 6 is a perspective view of a conventional angular velocity sensor, FIG. 7 is a front view showing the vibrating direction of the tuning fork vibrating element, and FIG. Is a modeled top view of the vibration of the sensor element, and FIG. 9 is a modeled top view of the sensor element to which a lead wire is connected. 11a, 11b ...... Piezoelectric bimorph element for detection, 12, 13 ...... Piezoelectric bimorph element for driving, 14, 15 ...... Coupling member, 16 …… Base, 18a, 18b, 18c, 18d, 18e, 18f …… Lead pin, 19 ...
… Holding plate, 20a, 20b, 20c, 20d, 20e, 20f …… Lead wire.

Front page continued (72) Inventor Shinji Tsukiji 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Shigeru Kawabata 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Invention Yukio Nishikawa 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Mamoru Matsuda 1006 Kadoma, Kadoma City, Osaka Prefecture Matsuda Electric Industrial Co., Ltd. (72) Inventor, Tateishi Uta Kadoma, Osaka Kadoma 1006 Matsushita Electric Industrial Co., Ltd. (72) Inventor Kenichiro Kawamura, Kadoma City, Osaka Prefecture 1006 Kadoma Matsushita Electric Industrial Co., Ltd. (56) Reference JP 62-229023 (JP, A) JP Sho 63 -290911 (JP, A) JP 62-36516 (JP, A)

Claims (3)

[Claims] 1. A sensor element comprising a driving piezoelectric bimorph element and a detection piezoelectric bimorph element which are coaxially orthogonally coupled to each other via a coupling member, and electrically connected to the detection piezoelectric bimorph element of the sensor element. And a ring-shaped holder for fixing a plurality of lead terminals for holding the other end of the lead wire in a position symmetrical with respect to the surface of the piezoelectric bimorph element for detection. 2. A sensor element comprising a driving piezoelectric bimorph element and a detecting piezoelectric bimorph element which are coaxially and orthogonally coupled to each other via a coupling member, and a pair of the sensor elements are provided at an end portion of the driving piezoelectric bimorph element. A tuning fork vibrating element configured by coupling through a coupling member, a lead wire electrically connected to the detecting piezoelectric bimorph element of the tuning fork vibrating element, and the lead wire with respect to the surface of the sensing piezoelectric bimorph element. Angular velocity sensor having a ring-shaped holder for fixing a plurality of lead terminals held at symmetrical positions. 3. The angular velocity sensor according to claim 2, wherein the holding body comprises a plurality of lead pins and a holding plate supported by the lead pins.