JPS62148811A - Rate sensor - Google Patents

Abstract

PURPOSE:To reduce the cost of a rate sensor and to reduce its temperature drift by putting a rectangular plate type vibrator in a nearly rectangular and cylindrical case and clamping the vibrator by one-terminal sides of the 1st and the 2nd supporting shafts, and providing a displacement detecting means which detects the vibration displacement of the vibrator due to Coriolis force. CONSTITUTION:The nearly rectangular plate type vibrator 12 is put in the rectangular and cylindrical case 11. The vibrator 12 is formed of a ferromagnetic material, square openings 13-1-13-4 are formed, and the vibrator is held by the 1st and the 2nd supporting shafts 14-1 and 14-2. An electromagnet 15 is fixed closely opposite the plate surface of the vibrator 12 and winding terminals t1 and t2 of the coil of the electromagnet 15 are led out of the case 11. Electrode plates 16-1 and 16-2 of the capacitor of a displacement detecting means which detects the displacement of the vibrator are fixed in the case and lead-out terminals t3 and t4 from the electrode plates 16-1 and 16-2 are led out of the case 11. When an exciting AC voltage is impressed between the winding terminals t1 and t2 of the coil of the electromagnet 15, the vibrator 12 vibrates about a vibration axis penetrating the vibrator in its center.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a rate sensor that detects an angular velocity to be measured.

"Prior art" When an external force is applied to an object around its axis, and an angular velocity is applied to the object around an axis perpendicular to the axis,
Coriolis force is generated in this object in response to the centrifugal horn as well as the external force and angular velocity applied to the object.

Therefore, by measuring this Coriolis, 1?
It is possible to measure the rotational force neutralized by the rotating body.

FIG. 2 shows the configuration of this type of rate sensor that has been conventionally used. For example, Elinva (50% Fe, NiJ 59f) has a small temperature change in elastic modulus.

The vibrating body 1 is made of a rectangular shape such as an alloy containing 9.1% Cr).
2 is formed. A piezoelectric body 10°13.14.1 is placed at the center of each plate surface on the circumferential surface surrounding the vibrating body I2 along the yam direction.
3 are attached facing each other, and the vibrating body 12 is supported by support shafts 9-1 and 9-2 provided on mutually opposing plate surfaces. In the example shown in FIG. 2, the piezoelectric bodies IO and 14 form a vibrating means, and the vibrating body 12 performs bending vibration by driving electric signals applied to the piezoelectric bodies 10 and 14.

In this case, when the driving electric signal is supplied to the vibrating means, the vibrating body 12 uses the support shafts 9-1 and 9-2 as nodes, and
-1.9-2 is provided, bending vibration is performed as shown by the dotted line in FIG.

In other words, the upwardly bent state indicated by the dotted line in Fig. 3 is 12-1;
In addition, as shown by 12-2 in the downwardly bent state indicated by the dotted line, the vibrating body 12 is located within the X-7 plane in the coordinate system shown in FIG. 3 with the support axis □hJ+9-1. Perform bending vibration.

A constant angular velocity ω is manually applied to the longitudinal axis of the vibrating body 12, that is, the X axis shown in FIGS. 2 and 3.

The bending vibration given to the vibrating body 12 by the vibrating means can be considered as part of the rotational movement of the top whose rotational direction changes all over the circumference. Therefore, in Figure 2,
Coriolis force is generated in the vibrating body 12 in the z-axis direction perpendicular to the input axis X of the measured angular velocity ω and the y-axis, which is the direction of vibration of the vibrating body 12 by the vibrating means. This Coriolis causes the vibrating body 12 to perform bending vibration in two axial directions within the xz plane.

The bending vibration of the vibrating body 12 due to this Coriolis is detected by the piezoelectric body 13.degree. 15 disposed in contact with the plate surface of the vibrating body 12 to which the support shaft 9-1, 9-2 is attached. The detected electrical signal from the piezoelectric body 13.15 is proportional to the measured angular velocity input to the vibrating body 12. Therefore, by measuring the detected electrical signals of the piezoelectric bodies 13 and 15, the measured angular velocity given to the vibrating body 12 can be measured.

“Problems to be solved by the invention” In the conventionally used rate sensor, two support shafts 9
-1.9-2 supports the vibrating body 12 in the longitudinal direction, so there is stress imbalance and thermal expansion coefficient that occur at the joints between the support shafts 9-1 and 9-2 and the vibrating body 12. There is a difference between the vibrating body 12 and the piezoelectric body 1, which are arranged in contact with each other.
There is a difference in coefficient of thermal expansion of 0.13.14°15, which causes problems such as temperature drift and uneven stress. In addition, in order to make the vibrating body 12 vibrate three-dimensionally with high precision by the vibrating means, it is necessary to process the vibrating body 12 with high precision three-dimensionally, which complicates the manufacturing and JI setup work. There is also the disadvantage of increased costs.

This invention was made in addition to the conventional rate sensor mentioned above, and its purpose is to reduce manufacturing costs by making the vibrating body into a flat plate and limiting its processing to two-dimensional work, and to reduce manufacturing costs by using only one vibrating body. The structure is such that it is supported by a support shaft at a location.
It is an object of the present invention to provide a rate sensor that is made entirely of one type of material, thereby making it possible to significantly reduce temperature drift.

"Structure of the Invention" In the present invention, a rectangular plate-shaped vibrating body is housed in a substantially rectangular cylindrical case. The vibrating body housed in the case is sandwiched by one end of the first and second support shafts from both sides of the plate surface at an input axis position that passes through the center of the vibrating body and is perpendicular to the plate surface of the vibrating body. .

The other ends of these support shafts are in contact with opposing plate surfaces of the cases that are opposed to each other within the case, and the vibrating body is held and held within the case by these first and second support shafts.

A vibrating means for the vibrating body is provided within the case, and the vibrating body is vibrated about a vibration axis that passes through the center of the vibrating body and is perpendicular to the human power axis.

The angular velocity to be measured is input to the vibrating body from the opposing plate surface of the case via one of the first and second support shafts.

When the measured angular velocity is input to the vibrating body, a Corio q) force is generated in the vibrating body that vibrates and displaces the vibrating body around the displacement axis that is perpendicular to the input axis and the vibration axis, passing through the center of the vibrating body. do. Displacement detection means for detecting vibrational displacement of the vibrating body due to Coriolika is provided within the case.

In this way, the rectangular plate-shaped vibrating body is held in the rectangular cylindrical case by the first and second support shafts at one point at the input shaft center position, so that vibration with high vibration accuracy can be achieved by two-dimensional machining. body can be created. In addition, since the displacement detection means for detecting the vibration displacement of the vibrating body using Coriolica can be disposed inside the case without contacting the vibrating body, stress generated at the joint between the support shaft and the vibrating body can be reduced. There is little unbalance, and there is no effect of a difference in thermal expansion coefficient due to contact between the displacement detection means and the vibrating body.

Therefore, it becomes possible to efficiently manufacture a rate sensor capable of highly accurate detection of the angular velocity to be measured using a simple manufacturing technique.

"Embodiments of the Invention" Below, the rate sensor of this invention will be described in Section 7. ``Examples will be explained in detail using drawings.

A substantially rectangular plate-shaped vibrating body is housed in a substantially rectangular cylindrical case, and this vibrating body is held in the case by first and second support shafts at the input axis position from both sides of the plate surface. .

FIGS. 1(A) and 1(B) show the structure of an embodiment of the rate sensor of the present invention, in which a rectangular cylindrical case 11 is constructed, and a substantially rectangular plate-shaped vibrating body 12 is accommodated in the case 11. be done. In the embodiment, a square plate-shaped vibrating body 12 is formed of a ferromagnetic material, and square-shaped openings 13-1 to 13-4 are formed in this vibrating body 12 symmetrically about the center.

The vibrating body 12 is connected to the case 11 by first and second support shafts.
It is clamped and held inside. That is, the first and second support shafts 14
-1. One end of 14-2 is formed into a pointed shape, and the support shaft 14-
1. The other end of 14-2 is formed into a flat shape. By one end of the first and second support shafts 14-1 and 14-2, the plate surface is sandwiched from both the front and back sides at the human power axis position passing through the center of the vibrating body 12 and perpendicular to the plate surface of the vibrating body 12, Vibrating body 12
First and second support shafts 14-1, 14-2 are disposed relative to each other.

The other planar ends of the first and second support shafts 14-1 and 14-2 are pressed against the opposing plate surfaces of the case 11. The thickness of the vibrating body 12 and the lengths of the first and second support shafts 14-1 and 14-2 are selected, and the vibrating body 12
is configured to be elastically clamped in the case 11 by the first and second support shafts 14-1 and 14-2 from both sides.

A vibrating means for the vibrating body is provided within the case. In the embodiment, within the case 11, an electromagnet 15 is fixed to the inner surface of the case 11 at the center of one periphery of the vibrating body 12, close to and facing the plate surface of the vibrating body 12.

The winding VA terminal t1 of the coil of this electromagnet 15. L2 is exposed outside the case 11.

Displacement detection means for detecting displacement of the vibrating body 12 is provided within the case. In the embodiment, the electromagnet I of the vibrating body 12
At the center of the periphery perpendicular to the periphery facing 5, the pole plates 16-1 and 16-2 of the two-layer tensor are held against the inner surface of the case 11 by the holder I7 with the plate surface of the vibrating body 12 in between. is fixed. Capacitor plate 16-1.16
The ξ output terminal “l + ”a from −2 is led out of the case 11.

Winding terminal of the coil of electromagnet 15 1. ．． An excitation AC voltage is applied between 12 and 12. By applying this excitation AC voltage,
The electromagnet 15 is excited, and the field formed by the electromagnet 15 causes the vibrating body 12 to move through the center of the vibrating body 12, at right angles to the human power axis which is perpendicular to the plate surface, and whose vibration axis passes through the center of the vibrating body 12. In the example, it vibrates around the y-axis in FIG. 1(A).

As shown in FIG. 4, an electromagnet 15
Due to the erection of , it receives a force in the direction of the arrow, and vibrates around the y-axis perpendicular to the plane of the paper, taking the positions shown by the solid and dotted lines in FIG.

The angular velocity to be measured is manually applied to the vibrating body from the plate surface of the case via one of the first and second support shafts. As shown in FIG. 5, the case 11 of the rate sensor of the present invention is carried close to the object 21 whose angular velocity is to be measured, and the plate surface of the case 11 is placed against the vibrating body 12 of the rate sensor. and input the angular velocity ω to be measured. That is, in the embodiment, the tip of the rotating shaft 22, which rotates at a constant angular velocity of 1 UII, is brought into contact with the plate surface of the case 11 of the rate sensor.

When the angular velocity to be measured is input to the plate surface of the case 11 that is in contact with the support shaft 14-1, a rotational force due to the angular velocity to be measured is applied to the vibrating body 12 of the rate sensor with respect to the input axis. The vibrating body 12 performs a vibrating motion centered on the vibration axis, that is, a rotational motion whose rotational direction changes periodically. A rotational force is applied to the

Under this condition, a Coriolis force is generated in the vibrating body 12 of the rate sensor, and the vibrating body 12 is displaced by the Coriolis with respect to a displacement axis in a direction perpendicular to the input axis and the vibration axis. The amplitude of the vibration of the vibrating body 12 about the vibration axis, ie, the displacement, is time, and the angular velocity of the vibration is ω. , a is a constant and is expressed by the following equation.

X ”' a Sln'l'.t
fil Therefore, the velocity in the amplitude direction is given by the following equation.

Coriolis f, which is generated when an angular velocity ω is applied manually to the human-powered axis of the vibrating body 12 rotating at the speed given by equation (2) about the vibration axis, is expressed by the following equation with C1 as a constant: is given by

f = C, a ωω, cos ωo t
, 131(3), the displacement y caused by Coriolis' as the center of the displacement axis is expressed by the following equation with C2 as a constant.

y= C+ Cz a (11th) a cos
ωo t =・(41 Here, the constants C+ and Cz are
It is given by the shape of the vibrating body 12 and Young's modulus.

In the embodiment, a square opening 13- is provided in the vibrating body 12.
1 to 13-4 are formed symmetrically around the center. When these openings 13-1 to 13-4 are provided, the vibrating body 1
This has the effect of reducing deviation of the vibration axis when driven by the second vibration means. In FIG. 6(A), the square-shaped vibrating body 12 in which openings 13-1 to 13-4 are not formed is not shown centered on the vibration axis (the y-axis in FIG. 6(A)). It is assumed that the vibration means is used to vibrate. In this case, if for some reason this vibration axis is tilted at an angle θ around the center of the vibrating body 12, then what is the effective length of the vibration center axis? to i′. However, since the angle θ is a small angle, p! ′ is not very large.

On the other hand, as shown in FIG. 6(B), the openings 13-1 to 1
In the vibrating body 12 in which the opening 13-4 is formed, when the vibration axis is tilted by a small angle θ, the effective length of the vibration central axis becomes , the effective length changes significantly from the case where no slope occurs.

Therefore, in the vibrating body 12 in which the openings 13-1 to 13-4 are formed, even if the vibration center axis changes slightly,
Since the vibration frequency changes greatly, a force acts on the vibrating body 12 to return the inclination to its original state, suppressing fluctuations in the central axis of vibration.

On the other hand, in the vibrating body 12 in which the openings 13-1 to 13-4 are not formed, there is little change in the vibration frequency even if the vibration center axis changes slightly, so that the vibration frequency is centered around the changed vibration center axis. The vibration will continue, causing a shift in the vibration center axis.

(4) The displacement y generated in the vibrating body 12, indicated by 2, is detected by the displacement detection means. In the embodiment, a capacitance detection method is used as the displacement detection means. Immediately, the capacitor plate 16-1 or 16-2 and the vibrating body 12 facing it
The change in the capacitance value formed by the vibrating body 12 due to the movement of the vibrating body 12 is measured, and the displacement y occurring in the vibrating body 12 is determined from the change in the capacitance value.

In FIG. 7, the vibrating body 12 and the capacitor pole (anti-16
-2 is the capacitance between the vibrating body 12 bottle (16-1.1
It is given by the following equation, where y is the displacement from the center position between 6 and 2. However, the area of the opposing plate of the capacitor is S, and the pole of the capacitor is 16-1. Let D be the distance between 16-2.

'AD y At this time, the capacitance between the capacitor plate l6-1 and the vibrating body 12 is given by equation (6).

In this way, by measuring the capacitance MC obtained between the terminals t1' and t3 or between the terminals L1' and t4, and using these, it is possible to determine the displacement y of the vibrating body 12 due to Coriolis. When the displacement y of the vibrating body 12 due to Coriolis f is determined by the displacement detection means, (
The angular velocity ω to be measured can be found from equation 4).

The displacement given to the vibrating body 12 by the Coriolika f in one ship is smaller than that given to the vibrating body 12 by the vibrating means.

As described in the embodiment, in this invention, the vibrating body 1
2, the displacement detecting means can be arranged in a non-contact manner (it can be arranged by voice), and the displacement detecting means can be arranged in a non-contact manner, and
-2 also holds the vibrating body 12 at one point from both sides. Therefore, no asymmetrical stress is generated in the connecting portion between the support shaft and the vibrating body, and a configuration can be achieved in which the occurrence of temperature drift is extremely small.

The machining of the vibrating body 12 itself is two-dimensional machining, and three-dimensional high-precision machining is not required, and the entire rate sensor can be easily manufactured and assembled, and it is small and portable, and it is easy to measure the angular velocity to be measured. It is possible to provide a rate sensor with stable detection accuracy.

In the embodiment, one electromagnet 15 is used as a vibration means for the vibrating body 12, but it is also possible to use a plurality of electromagnets to vibrate the vibrating body 12 more effectively around the vibration axis. Although not shown in the embodiment, means for detecting the amplitude of the vibrating means of the vibrating body 12 is provided, and the vibration of the vibrating body 12 is adjusted according to the detected value of the detecting means. It is also possible to perform more stable vibrations on the vibrating body by controlling the above.

In addition, in the embodiment, the vibrating body 1 is used as a displacement detecting means.
Although the method of detecting the change in capacitance due to the displacement of 2 is used, it is not limited to the configuration of the embodiment. You can also do that.

1-Effects of the Invention" As explained in detail above, according to the present invention, manufacturing and assembly can be carried out at nodes i [i, and the overall size can be reduced, and there is no mechanical distortion or distortion in the assembled state. , there is no temperature drift, and high-precision constant angular velocity detection can be performed quickly and easily on-site by simply placing f + H on the object to be measured. It is possible to provide

[Brief explanation of drawings]

Fig. 1(A) (13) shows the configuration of an embodiment of the rate sensor of the present invention, a front cutaway view and a side cutaway view with the top cover and side plate removed, respectively, and Fig. 2 shows the configuration of a conventionally used rate sensor.
FIG. 3 is a perspective view showing the configuration of the rate sensor.
FIG. 4 is a front view showing the vibration state of the vibration means of the rate sensor of the present invention; FIG. 4 is a cutaway plan view showing the vibration state of the vibration means of the rate sensor according to the embodiment of the invention; Figures 6(A) and 6(B), which are perspective views showing the blowout state of the measured angular velocity of the measured object, show the vibration centering on the vibration axis of a vibrating body without an opening and a vibrating body with an opening, respectively. FIG. 7 is a diagram showing the (1'4 configuration) of the displacement detecting means used in the embodiment of the present invention. 11: Case, 12. Vibrating body, 13-1 to 13-4: Opening, 14-1; first support shaft,
14-2・Second support shaft, 15: Electromagnet, 16-1.1
6-2 Electrode plate, 17: Holder, 21: Target i1 [+I constant body, 22; Axis to be measured. Agent, 1'1°t field
Market 1k (A) (B) + 2 figures 11 thousand figures 5 O 6 circles (c) (B) 7
figure

Claims (1)

[Claims] (1) A rectangular plate-shaped vibrating body is housed in a substantially rectangular cylindrical case, and this vibrating body passes through the center of the vibrating body from both sides of the plate surface at an input axis position perpendicular to the plate surface, The other ends of the first and second support shafts are held by one end of the first and second support shafts, and the other ends of the first and second support shafts are in contact with opposing plate surfaces of the case that face each other within the case. The vibrating body is held and held in the case by a second support shaft, and a vibrating means for the vibrating body is provided in the case, and the vibrating body passes through the center and is perpendicular to the input axis. A measured angular velocity is input to the vibrating body from the opposing plate surface of the case through one of the first and second support shafts, and the measured angular velocity causes the vibration body to vibrate. A Coriolis force is generated that passes through the center of the vibrating body and vibrates and displaces the vibrating body around a displacement axis perpendicular to the input axis and the vibration axis, and the displacement of the vibrating body due to this Coriolis force is A rate sensor characterized in that displacement detection means for detecting displacement is provided within the case.