JP2939922B2 - Acceleration transducer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acceleration transducer,
More specifically, a weight is supported via a flexible portion on a driven portion that moves integrally with the measured object, and when the driven portion receives acceleration, the weight is moved relative to the driven portion. The present invention relates to an acceleration converter of a type in which a strain at the time of relative displacement is converted into an electric signal by a strain gauge to detect the acceleration.

[0002]

2. Description of the Related Art Acceleration transducers are widely used, for example, when measuring the impact strength of a structure or analyzing the acceleration waveform of vibration generated in the structure. As a conventional acceleration converter used in this way, for example, when the driven portion is subjected to acceleration, the weight is displaced relative to the driven portion to generate a strain, that is, the acceleration is sensed. An electric resistance type strain gauge (in the form of foil or wire) attached to the surface of a flexure element, the resistance value of which varies with strain
No. 52899) and a type to which a diffusion type semiconductor gauge is attached (Japanese Patent Application Laid-Open No. 59-158566).

[0003]

In such an acceleration converter, it is required that the output signal be sufficiently large with respect to noise even with a small acceleration, and that the response be good. As a measure for improving the sensitivity of the acceleration converter, there is a method of increasing the weight and increasing the beam displacement.

[0004] However, this method has a disadvantage that the natural frequency is low and the response frequency range is narrow. Also, if the spring constant of the strain-generating portion is reduced, the flexure of the strain-generating portion increases and the strain output increases, but the natural frequency decreases and the response frequency range narrows as described above.

In addition, in order to develop an ultra-small acceleration transducer, it is necessary to minimize the strain gauge, but the current metal foil strain gauge method has certain limitations, and is small in size and has a high resistance value. At present, it is difficult to manufacture a strain gauge having a specific resistance. On the other hand, besides the electric resistance type strain gauge,
There is one using the above-mentioned diffusion type semiconductor,
A strain-receiving element is formed by forming a strain generating body on a crystalline silicon substrate and forming a diffusion type semiconductor on the substrate.

[0006] In the case of this diffusion type semiconductor gauge, although the gauge factor can be obtained much higher than that of the above-mentioned electric resistance type strain gauge, it has a large temperature coefficient of resistance and therefore requires a complicated temperature compensation circuit. Since the silicon substrate has a low elasticity limit and is brittle, great care must be taken at the time of assembling, and brittle fracture is easily caused by mechanical overload.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to make it possible to increase the strain output sensitivity while increasing the natural frequency, and to facilitate the assembly. Another object of the present invention is to provide an acceleration converter that can be used stably for a long period of time.

[0008]

According to a first aspect of the present invention, there is provided a weight unit via a flexible portion provided on a driven portion which moves integrally with an object to be measured. Is supported, and when the driven portion receives acceleration, the weight is displaced relative to the driven portion, and the strain is converted into an electric signal by a strain gauge to detect the acceleration. By forming slits of a certain depth from both sides of the opposing side peripheral surface in the middle part of the beam having a rectangular cross section, a rigidly driven portion is provided at the base end and a rigid driven portion is provided at the distal end. The large weight portion, a flexible portion having a flexible portion in the middle portion, and a cantilever beam provided, respectively, and a pair of slits formed in the middle portion of the cantilever beam so as to straddle. Thin sections respectively joined to the peripheral surfaces of the weight section and the weight section. A pair of strain generating plates having flexibility and a portion corresponding to the slit formed narrow, and strain can be detected in a narrow slit-side surface layer portion of the pair of strain generating plates. In this manner, two strain gauges are attached to each other, and the tensile and compressive strain acting on the strain plate by deforming the cantilever with acceleration acting on the weight portion, The present invention is characterized in that a bending strain caused by deformation of the strain generating plate itself is added by acceleration acting on the strain generating plate, and the strain can be detected by the strain gauge.

According to another aspect of the present invention, a weight is supported via a flexible portion on a driven portion that moves integrally with the object to be measured. In an acceleration converter of a type in which a strain when the weight is relatively displaced with respect to the driven part when the driven part receives acceleration is converted into an electric signal by a strain gauge and the acceleration is detected, a rectangular cross section is used. By forming a pair of through-holes extending from one side surface to the other side surface of the beam at an intermediate portion of the beam, a driven portion having high rigidity is provided at the base end and a rigid driven portion is provided at the distal end side. A weight portion, a flexible portion having flexibility at a central portion in the plate thickness direction at an intermediate portion of the beam,
At the end in the thickness direction of the beam, a pair of strain-generating portions each having a smaller thickness and flexibility than the flexible portion are provided, and the rectangular shape of the pair of strain-generating portions is provided. At least one pair of strain gauges respectively attached to the shape through-hole side surface layer so that strain can be detected, and the cantilever is deformed by acceleration acting on the weight portion. The strain gauge is configured to be able to detect a tensile / compressive strain acting on the strain-generating portion and a bending strain caused by the deformation of the strain-generating portion itself by an acceleration acting on the strain-generating portion. It is characterized by the following.

[0010]

In the acceleration converter constructed as described above, the flexible portion formed in the intermediate portion of the cantilever beam functions as a beam hinge and receives acceleration from the object to be measured via the driven portion. At this time, bending strain is intensively generated in the flexible portion. But,
The pair of strain plates, which are joined to the peripheral portions on both sides of the driven portion and the weight portion so as to straddle a pair of opposed slits formed to provide the flexible portion, respectively, prevent bending of the beam. One strain plate receives a tensile force and the other strain plate receives a compressive force to generate tensile strain or compressive strain, respectively.

On the other hand, not only these tensile and compressive strains are generated in the strain-generating plate, but also bending strain is generated due to the deformation of the strain-generating plate itself by the acceleration acting on the strain-generating plate. I do.

[0012] Therefore, two strain gauges, which are attached to the inside or the opposing surfaces of the pair of strain generating plates, in other words, on the slit side surface portion of the strain generating plate, are provided between the driven portion and the weight. Not only tensile strain or compressive strain due to the increase or decrease of the gap, but also bending strain that the flexure plate itself is bent by receiving acceleration is added, and the strain output can be greatly increased. You can.

Further, a pair of through holes extending from one side surface of the beam to the other side surface are formed at an intermediate portion of the cantilever, so that the beam is provided at the center of the beam in the thickness direction (acceleration application direction). The flexible portion also functions as a hinge, and when receiving acceleration from the measured object via the driven portion, bending strain is intensively generated in the flexible portion.

[0014] A pair of strain-generating portions integrally provided at the ends in the thickness direction of the beam also function to prevent bending of the beam, and one of the strain-generating portions receives a tensile force. The other strain-generating portion receives a compressive force and generates a tensile strain or a compressive strain, respectively. On the other hand, not only these tensile and compressive strains are generated in the strain-generating portion, but also bending strain is generated due to the deformation of the strain-generating portion itself due to the acceleration acting on the strain-generating portion.

Therefore, the strain gauge attached to the inside or the opposing surfaces of the pair of strain-generating portions, in other words, the strain gauge attached to the slit-side surface portion of the strain-generating portion, is used to increase or decrease the gap between the driven portion and the weight. Not only the tensile strain or the compressive strain caused but also the bending strain which is caused by the strained portion itself to be curved by the acceleration is detected, and the strain output can be greatly increased.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a side sectional view schematically showing the entire configuration of the acceleration converter according to the present invention, and FIG. 2 is a view showing the configuration of the acceleration converter in a state where a casing is removed in order to explain the operation of the embodiment. FIG. 3 is a cross-sectional view schematically showing a relationship between a flexible portion of a cantilever, a strain plate, and a strain gauge in the embodiment of FIG. 1, and FIG. 4 is a configuration of the embodiment of FIG. FIG.

FIG. 5 is an exploded perspective view showing the relationship between the lower strain plate used in the embodiment shown in FIG. 4 and two strain gauges laminated thereon, and FIG. 1 to 5
FIG. 4 is a circuit diagram showing a configuration of a Wheatstone bridge circuit assembled with a strain gauge attached to a strain plate of the embodiment shown in FIG.

In FIG. 1, a casing 1 of the acceleration converter is formed in a quadrangular cylindrical body, and one surface side of the casing 1 (in FIG. 1, fixing means such as a screw on the wall surface of the object 2 to be measured). On the inner peripheral wall of the casing 1, a base end of the cantilever 3, that is, a base end of the driven portion 3a is screwed, although not shown.
It is firmly fixed by welding or other fixing means.

The method of forming the cantilever 3 is as follows. The slits 3b, 3 having a certain depth from opposing side peripheral surfaces (the upper surface and the lower surface in FIG. 1) are formed in the middle of the beam having a rectangular cross section.
By forming c, a flexible portion 3d having a predetermined thickness h is provided at the center in the thickness direction of the beam, and a weight portion 3e is provided on the tip side (free end side) of the flexible portion 3d. I have.

That is, the flexible portion 3d is thin and flexible, and has a hinge function when acceleration is applied to the driven portion 3a, so that the driven portion 3a and the weight 3e are separated from each other. And the flexible portion 3d is sufficiently thicker than the flexible portion 3d, has high rigidity, and does not bend even when substantially subjected to acceleration. It is an element that determines the frequency and also an element that determines the acceleration detection sensitivity.

The driven part 3 is set so as to straddle (bridge) a pair of slits 3b and 3c formed in an intermediate part of the cantilever 3.
a and spring members, for example, strip-shaped strain-generating plates 4 and 5 made of an alloy material such as beryllium copper and phosphor bronze are bonded, welded, screwed, and other means to the above-mentioned peripheral surfaces of the weight 3e. , Are firmly joined.

In other words, the plate surfaces of the strain plates 4 and 5 are set in parallel with the plate surface of the flexible portion 3d when no load is applied (when no acceleration is applied).
In the strain plates 4 and 5, portions corresponding to the slits 3b and 3c are formed narrow, for example, so that one strain gauge can be attached.

The slits 3b and 3 of the strain plates 4 and 5
As shown by broken lines in FIG. 4, each of the two surface strain portions SG1 and SG2 is provided on each surface layer portion facing c, that is, each surface layer portion on the inner surface opposed to each other with the flexible portion 3d interposed therebetween. SG3, SG4 not shown in the figure are bonded, CV
The two layers are attached by chemical vapor deposition such as D or physical vapor deposition means such as sputtering.

The strain gauges SG1 to SG4 are shown in FIG.
As shown in FIG. 2, the sensing axes are directed along the longitudinal direction of the cantilever 3 so that the two plates,
The sensing part is slit 3 so that
It is attached so as to be located at the center of the portion facing b and 3c.

The strain gauges SG1 to SG4 are
In the case of this embodiment, since the strain plates 4 and 5 are made of a conductor (Cu alloy) in the case of vapor deposition, fusion, etc.
It is necessary to form an appropriate means, for example, an insulating film such as a SiO ₂ film on the surfaces of the strain generating plates 4 and 5 in advance.

One end of a gauge lead is connected to each of the gauge tabs of the strain gauges SG1 to SG4, and the other end of the gauge lead is connected to a measuring device for measuring acceleration via a gauge terminal, a lead wire, or the like. Led,
Inside or near the acceleration transducer, the strain plate 4
As shown in FIG. 6, the strain gauges SG1 and SG2 attached on the upper side are opposite to each other, and the other strain gauges SG3 and SG4 attached on the strain generating plate 5 are on opposite sides adjacent thereto. Are connected to form a Wheatstone bridge circuit (hereinafter abbreviated as “bridge circuit”).

Although not shown, an external resistor or the like for adjusting the initial imbalance of the bridge circuit and for compensating for the temperature is added to the bridge circuit.

Next, the operation of the acceleration converter configured as described above will be described. It is assumed that the acceleration converter has its casing 1 screwed to the measured object 2 and firmly fixed by other means. In this state, when the inertial force F acts on the cantilever 3 as shown in FIG. 2, for example, due to vibration or impact of the measured object 2, the weight 3e is relatively displaced with respect to the casing 1, and While bending the bending portion 3d, the narrow portions of the pair of upper and lower strain plates 4 and 5 are bent as shown in FIG.

At this time, the upper strain plate 4 is provided with the slit 3b.
As shown in FIG. 2, when the opening end (upper end) is deformed so that the opening end (upper end) is opened, it is subjected to a pulling force and acceleration is applied to the strain generating plate 4 itself, as shown in FIG. Side), on the anti-slit side (outer side or upper side) of the strain plate 4,
A compressive strain is generated, and a tensile strain is generated on the slit 3b side.

The lower strain plate 5 is compressed by receiving a compressive force to deform so that the opening end of the slit 3c closes, and acceleration is applied to the strain plate 5 itself, as shown in FIG. As shown in FIG. 5, since the flexure plate 5 bends to the side opposite to the slit 3c (the outer surface side or the lower surface side), a compressive strain is generated on the slit 3c side of the strain generating plate 5, and the side opposite to the slit 3c (the outer surface). Side or the lower surface side), tensile strain occurs.

Therefore, two strain gauges SG1 and SG1, which are superimposed and attached to the surface layer on the slit 3b side of the strain plate 4,
2 is the acceleration acting on the weight 3e, the cantilever 3 is deformed as shown in FIG. 2, the tensile strain caused by the spread of the opening end (upper end) of the slit 3b, and the acceleration acting on the strain generating plate 4 The tensile strain due to the bending of the strain generating plate 4 itself swelling downward is detected, and the resistance value is greatly increased.

On the other hand, two strain gauges SG3 and SG4 superimposed and attached to the surface layer on the slit 3c side of the strain plate 5
2, the cantilever 3 is deformed by the acceleration acting on the weight 3e as shown in FIG. 2, and the compression strain caused by the narrowing of the opening end (lower end) of the slit 3c and the acceleration acting on the strain generating plate 5 Compressive strain caused by bending of the strain-generating plate 5 itself swelling downward is detected, and the resistance value is greatly reduced.

The explanation of the operation described above is based on the case 1
In the case where acceleration is applied in the upward direction, the weight portion 3e is applied when acceleration is applied in the downward direction.
Is relatively displaced upward by the inertia force using the flexible portion 3d as a hinge, so that the resistance values of the strain gauges SG1 and SG2 attached to the surface of the strain-generating plate 4 on the side of the slit 3b are opposite to those described above. It is easily understood that the resistance value of the strain gauges SG3 and SG4 attached to the surface of the strain generating plate 5 on the side of the slit 3c greatly decreases and greatly increases.

In contrast to the above embodiment, when a strain gauge is attached to the upper strain plate 4 on the side opposite to the slit 3b (upper side), the cantilever 3 is moved as shown in FIG. If it is deformed, a tensile force acts on the strain generating plate 4 due to the separation of the surface layer between the driven portion 3a and the weight portion 3e, and a tensile strain is generated. As a result, the surface layer on the side opposite to the slit generates a compressive strain, and the two cancel each other out, resulting in the strain gauge detecting only a small tensile strain. There is a disadvantage that it is greatly reduced and the S / N ratio is deteriorated.

Similarly, when a strain gauge is attached to the lower side of the strain generating plate 5 on the opposite side (lower side) to the slit 3c, unlike the above-described embodiment, the cantilever 3 of FIG. If such deformation occurs, a compression force acts on the strain-generating plate 5 due to the closeness of the surface layer between the driven portion 3a and the weight portion 3e, and a compressive strain is generated. The surface layer on the opposite side of the slit generates tensile strain due to its own deformation due to acceleration, so the two cancel each other out, resulting in the strain gauge detecting only a small compressive strain. Therefore, there is a disadvantage that the distortion output is greatly reduced and the S / N ratio is deteriorated.

The above-described embodiment has been devised in order to greatly increase the output sensitivity. The feature of the embodiment is that firstly, the pair of upper and lower strain plates 4 and 5 The portions corresponding to the slits 3b and 3c are formed narrow enough to allow one strain gauge to be attached. Second, the strain gauges SG1 and SG2 and SG3 and SG4
Are attached to the respective slits 3b and 3c sides of the strain plates 4 and 5 so as to be stacked in two stages.

As described above, the intermediate portion between the strain generating plates 4 and 5 is formed to be narrow and the strain gauges SG1, SG2 and SG
How the large strain output can be rationally obtained by stacking two G3s and SG4s will be described.

FIG. 3 is a sectional view taken along line XX of FIG. 1 and shows the relationship between the follower of the cantilever, the strain plate, and the strain gauge. In the figure, b is the width of the flexible portion 3d, h
Is the thickness of the flexible portion 3d, H is the distance between the upper and lower strain plates 4 and 5, and t is the thickness of the pair of strain plates 4 and 5.

Referring to FIG. 3, when examining factors that can increase the strain output of the acceleration transducer, the strain amount of the surface layers of the strain plates 4 and 5 is set to ε, and H / 2 from the neutral axis of the cross section. The tensile and compressive stress at the distance point is σ, the longitudinal elastic modulus is E,
Assuming that the secondary moment of area about the neutral axis of the cross section is I and the bending moment applied is M,

The relationship between the strain ε, the stress σ, and the modulus of longitudinal elasticity (Young's modulus) E is ε = σ / E, and the relationship between the stress σ, the bending moment M, and the second moment of area I is σ = σ / E (M / I) is y, the second moment I ^{are, I = (bh 3/12} ) +2 [(bt 3/12) + {(H
+ T) / 2 ^ ² bt].

From the above equation, it is sufficient to reduce the second moment of area I in order to increase the strain ε. Therefore, the width b of the flexible portion 3 d and the width b of the strain plates 4 and 5 shown in FIG. It is considered that the thickness t of the strain plates 4 and 5 and the thickness h of the flexible portion 3d may be reduced. Of these, when the thickness h of the flexible portion 3d is reduced, there is a problem in that the natural frequency is greatly reduced. Rather, the reduction in the thickness t of the strain plates 4 and 5 causes a reduction in the natural frequency. It turned out not to be so big.
However, since the strain plates 4 and 5 need to have a function of reinforcing the cantilever 3, they cannot be made very thin.

Next, as an effective means for increasing the strain output, there is a way to reduce the width b of the strain plates 4, 5.
Since the strain gauge has a certain width limit, if two strain gauges are to be attached in parallel, the width b
Is naturally limited, and this method also has a limit on the effect of increasing the amount of strain.

The most effective measure for increasing the amount of strain while maintaining the reinforcing effect of the strain plates 4, 5 is shown in FIGS.
As in the embodiment shown in FIG. 6, two strain gauges SG1 and SG2 and SG3 and SG4 are provided with constrictions in the strain generating plates 4 and 5 so as to be narrow enough to allow one strain gauge to be attached. This is a method of laminating by overlapping and attaching.

According to the embodiment described above, the first
In addition, not only can a larger strain output be obtained as compared with the case where two strain gauges are attached in parallel on the surface of the flexible portion 3d, but also the thin thin strain plates 4 and 5 having flexibility are formed by slits 3b. , 3c, and bridging, and the central portion corresponding to the slits 3b, 3c is formed to be narrow, so that the cantilever 3 can be effectively reinforced. It is possible to provide a highly compact acceleration converter that is compact and robust without lowering the natural frequency.

Second, not only do the strain plates 4 and 5 function as reinforcing plates, but also the strain gauges SG1 to SG4 are attached to the front side, that is, the side opposite to the slits 3b and 3c. Since the tensile strain and the compressive strain corresponding to the bending strain caused by the deformation of the strain generating plates 4 and 5 by the acceleration acting on the strain plates 4 and 5 are added and detected, the same gauge sensitivity (gauge rate) is obtained. in the case of,
If a higher sensitivity is obtained and the weight of the weight 3e is adjusted, an acceleration converter that can obtain a high resonance frequency (natural frequency) even with the same sensitivity can be provided.

Third, since a high strain sensitivity is obtained by superposing and attaching two strain gauges as described above without using a semiconductor gauge as the strain gauge, the temperature is higher than that of the semiconductor gauge. Compensation is easy,
Since it is not brittle like a semiconductor gauge, it is not easily broken or peeled off, which makes it easier to assemble and has the advantage that initial set values are less likely to shift.
Since the semiconductor gauge is generally thick, when configured as in this embodiment, even if acceleration is applied to the strain-generating plate to which the semiconductor gauge is attached, the strain-generating plate bulges as shown in FIG. Although it does not show a deformation of the shape, it is not possible to improve the strain sensitivity, but by using a foil or a linear strain gauge or a strain gauge formed by vapor deposition, an acceleration transducer capable of exhibiting the first effect is provided. Can be provided.

The present invention is not limited to the embodiment described above and shown in the drawings, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, a strain gauge is attached to the strain plate, but a gauge element pattern film may be directly attached to the strain plate by physical vapor deposition such as sputtering or chemical vapor deposition such as CVD. , Within the scope of the present invention.

The number of strain gauges is not limited to two when one strain-generating plate is attached, and one or three or more strain gauges may be used. Further, in the above-described embodiment, the strain plates 4 and 5 are formed separately from the cantilever 3, but they may be formed integrally.

That is, as shown in FIG. 7, a pair of rectangular through holes 6b and 6c extending from one side to the other side instead of forming a slit in the intermediate portion of the cantilever 6 having a rectangular cross section. By drilling, a flexible portion 6d having flexibility is provided in the thickness direction of the beam, that is, in the center of the acceleration application direction,
Further, a pair of upper and lower strain generating portions 6f and 6g which are thinner and more flexible than the flexible portion 6d may be provided at the end of the beam in the thickness direction.

Also in this modified embodiment, a rigid rigid follower 6a is provided at the base end of the cantilever 6 and a rigid weight 6e is provided at the distal end thereof. A strain gauge SG is provided inside each of the pair of upper and lower strain generating portions 6f and 6g, that is, on the sides of the rectangular through holes 6b and 6c.
SG1, SG2, SG3, and SG4 are superimposed and attached.

However, the strain gauges SG1, SG2 and SG3, SG4 are not superposed on each other,
f, 6g may be attached two by two in parallel. Further, as shown in FIG. 7, each of the strain generating portions 6f and 6g
As shown in FIG. 4, if the width of the flexible portion 6 d is not made the same as that of the flexible portion 6 d but is made narrow enough to allow one strain gauge to be stuck, a high sensitivity and a high resonance frequency can be obtained. Also,
The through-hole is not limited to a rectangular through-hole, and may be an elliptical through-hole, an elliptical through-hole, or the like.

[0052]

As is apparent from the above description, according to the present invention, a relatively small size, a high strain sensitivity can be obtained without lowering the natural frequency, and a strong toughness against impact and vibration can be obtained. It is possible to provide an acceleration converter that has easy assembly work and temperature compensation, and can maintain stability for a long period of time.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a configuration of an embodiment of an acceleration converter according to the present invention.

FIG. 2 is a side sectional view for explaining the operation of the embodiment shown in FIG. 1;

FIG. 3 is a sectional view taken along line XX of FIG. 1 showing a relationship among a flexible portion, a strain plate, and a strain gauge of the embodiment shown in FIG.

FIG. 4 is a perspective view of the embodiment shown in FIG.

FIG. 5 is an exploded perspective view showing a relationship between a lower strain plate used in the embodiment shown in FIG. 1 and two strain gauges laminated thereon.

FIG. 6 shows 4 applied to the acceleration transducer according to the present invention.
FIG. 3 is a circuit diagram showing a configuration of a Wheatstone bridge circuit assembled by a single strain gauge.

FIG. 7 is a perspective view showing a configuration of a modified example of the acceleration converter according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 2 Object to be measured 3 Cantilever 3a Follower 3b, 3c Slit 3d Flexible part 3e Weight 4,5 Strain-generating plate 6 Cantilever 6a Follower 6b, 6c Rectangular through-hole 6d Flexible part 6e Weight part 6f, 6g Strain generating part SG1 to SG4 Strain gauge

Claims (5)

(57) [Claims] A weight is supported via a flexible part on a driven part that moves integrally with the object to be measured, and when the driven part receives an acceleration, the weight is moved relative to the driven part. An acceleration transducer that converts the strain at the time of relative displacement into an electric signal by a strain gauge and detects the acceleration is provided. By forming a slit of each,
A cantilever beam having a rigidly driven portion at the base end, a rigid weight portion at the distal end, and a flexible portion having flexibility at an intermediate portion; A thin and flexible portion which is joined to the both peripheral surfaces of the driven portion and the weight portion so as to straddle a pair of slits formed in an intermediate portion of the beam, and a portion corresponding to the slit is provided. A pair of strain plates having a narrow width, and a strain gauge which is superposed and attached to each of the pair of strain plates in such a manner that strain can be detected on a narrow slit-side surface portion of the pair of strain plates. And the tensile and compressive strain acting on the strain plate by the deformation of the cantilever with the acceleration acting on the weight portion, and the strain plate itself by the acceleration acting on the strain plate Bending strain caused by deformation can be added and detected by the strain gauge. Acceleration transducer, characterized in that the sea urchin configuration. 2. A weight is supported via a flexible part on a driven part which moves integrally with the object to be measured, and when the driven part is subjected to acceleration, the weight is moved with respect to the driven part. In an acceleration transducer of a type in which a strain at the time of relative displacement is converted into an electric signal by a strain gauge to detect the acceleration, an intermediate portion of a beam having a rectangular cross section is provided from one side of the beam to the other side. By forming a pair of through holes reaching each other, a rigidly driven portion at the base end side, a weight portion with a large rigidity at the distal end side, and a central portion in the plate thickness direction at an intermediate portion of the beam. A flexible portion having flexibility is provided at the end of the beam in the thickness direction of the beam.
A pair of strain-generating portions, at least one pair of strains respectively attached to the pair of strain-generating portions so that the strain can be detected on the rectangular through-hole-side surface portion of the pair of strain-generating portions. And a tensile / compressive strain acting on the strain-generating portion by deforming the cantilever with an acceleration acting on the weight portion, and a strain-generating strain acting on the strain-generating portion. An acceleration transducer characterized in that it is configured to be able to detect a bending strain caused by deformation of a part itself by the strain gauge. 3. The acceleration converter according to claim 2, wherein two strain gauges are attached to each strain generating portion in parallel. 4. A portion corresponding to the through hole of each strain generating portion is formed to be narrow, and two strain gauges are attached to the narrow portion in an overlapping manner. Item 3. The acceleration converter according to Item 2 or 3. 5. The acceleration converter according to claim 1, wherein the strain generating plate is made of beryllium copper or phosphor bronze and is formed to be thin so as to have flexibility.