JP7522341B2 - sensor - Google Patents

Description

The present invention relates to a sensor that detects vibration.

Figure 6 is a diagram illustrating an example of a device that uses a piezoelectric sensor to read vibrations transmitted to a measurement object. In the conventional device shown in Figure 6, a mounting stud (stake) is driven directly into the measurement object to fix the sensor, and the vibrations of the measurement object (floor surface) are converted into an electrical signal. Patent Document 1 discloses an invention for preventing damage to piezoelectric elements.

JP 2010-230459 A

For example, when conducting measurements on roads, the problem is that driving stakes into the road, which is public property, requires an application to the management authorities and repairs to the road, so road vibration measurements cannot be carried out easily.

The object of the present invention is to provide a means for easily performing measurements without causing damage to the object being measured.

The sensor of the first invention includes a piezoelectric element, a weight arranged next to the piezoelectric element,
and a guide for guiding the sliding of the weight.

In the present invention, a guide is provided to guide the sliding of the weight that is arranged alongside the piezoelectric element. Therefore, when the measurement object vibrates, the piezoelectric element is compressed between the measurement object and the weight that tends to stay in place due to the law of inertia, and the piezoelectric element efficiently generates a voltage. This eliminates the need to fix the sensor to the measurement object by driving a stake into the object, making it easy to perform measurements without damaging the measurement object.

The sensor of the second invention is the sensor of the first invention, characterized in that the weight is not fixed.

In the present invention, the weight is not fixed. In other words, the weight is in a floating state. This allows the weight to be in a state where there is almost nothing restraining it.

The sensor of the third invention is the sensor of the first or second invention, characterized in that the guide surrounds the outer periphery of the weight.

The sensor of the fourth invention is the sensor of the third invention, characterized in that the guide is provided with a protrusion that protrudes in the inner diameter direction of the guide.

The sensor of the fifth invention is the sensor of the fourth invention, characterized in that the weight is provided with a recess having a shape corresponding to the protrusion.

The sixth invention is a sensor according to the first or second invention, characterized in that the guide is inserted into a hole provided in the axial direction of the weight.

The sensor of the seventh invention is the sensor of the first or second invention, characterized in that the guide has a first guide surrounding the outer periphery of the weight and a second guide inserted into a hole passing through the axial direction of the weight.

The sensor of the eighth invention is a sensor of any one of the first to seventh inventions, further comprising a case that houses the piezoelectric element, the weight, and the guide inside.

The sensor of the ninth invention is a sensor of any one of the first to eighth inventions, characterized in that the weight has a substantially cylindrical shape.

The sensor of the tenth invention is the sensor of the ninth invention, further comprising a case that houses the piezoelectric element, the weight, and the guide, and the case has a hollow, generally cylindrical shape.

The sensor of the eleventh invention is the sensor of the eighth or tenth invention, further comprising a weight for pressing the case.

The sensor of the twelfth invention is characterized in that the sensor of any one of the first to eleventh inventions further includes an adjustment mechanism for adjusting the angle relative to the object to be measured.

In the present invention, the sensor is provided with an adjustment mechanism for adjusting the angle with respect to the measurement object. This allows the sensor to be in close contact with the measurement object even if the measurement object is tilted, not flat, or has irregularities.

The sensor of the thirteenth invention is the sensor of the twelfth invention, characterized in that the adjustment mechanism has an adjustment bar that extends approximately parallel to the object to be measured and swings from approximately parallel.

In the present invention, the adjustment mechanism has an adjustment bar that extends approximately parallel to the object to be measured and swings from approximately parallel. This allows the angle of the sensor relative to the object to be measured to be adjusted.

The sensor of the 14th invention is the sensor of the 13th invention, characterized in that the adjustment mechanism further has a support part that supports the adjustment bar.

The sensor of the 15th invention is the sensor of the 13th or 14th invention, characterized in that the adjustment mechanism has a cone portion formed in a roughly cone shape at the portion that contacts the measurement object.

According to the present invention, measurements can be easily performed without damaging the object being measured.

FIG. 1 is a diagram showing a sensor according to a first embodiment of the present invention. 1A is a perspective view showing a schematic diagram of a weight and an outer periphery guide, FIG. 1B is a plan view of an example of the weight and the outer periphery guide, and FIG. 1C and FIG. 1D are plan views of other examples of the weight and the outer periphery guide. FIG. 5 is a diagram showing a sensor according to a second embodiment of the present invention. FIG. 13 is a diagram showing sensitivity characteristics. FIG. 13 is a diagram showing a sensor according to a third embodiment of the present invention. FIG. 1 is a diagram showing an example of a conventional device.

The following describes an embodiment of the present invention.

First Embodiment
1 is a diagram showing a sensor 1 according to a first embodiment of the present invention. The sensor 1 includes a piezoelectric element 2, a weight 3, a guide 4, a case 5, etc. The sensor 1 is placed, for example, on a road that is a measurement target, and detects (measures) vibrations occurring on the road that is a measurement target.

The piezoelectric element 2 converts the force applied to the piezoelectric body into a voltage. The piezoelectric element 2 is, for example, a flat, approximately disk-shaped. The weight 3 is arranged side by side with the piezoelectric element 2. Specifically, the weight 3 is arranged side by side on top of the piezoelectric element 2. The weight 3 is guided by a guide 4 and slides up and down (vertically). The weight 3 is not connected to other members or fixed. In other words, the weight 3 is in a floating state from other members or the like. The weight 3 is, for example, approximately cylindrical. At the center of the weight 3 in a plan view, a hole is provided that extends in the axial direction and through which the shaft guide 7 described later is inserted. Note that the hole provided in the weight 3 does not penetrate the weight 3 for waterproofing, but may penetrate the weight 3.

The guide 4 guides the sliding of the weight 3 in the up-down direction (vertical direction). The guide 4 has an outer periphery guide 6 (first guide) and an axis guide 7 (second guide). The outer periphery guide 6 surrounds the outer periphery of the weight 3, which is approximately cylindrical. Therefore, the outer periphery guide 6 has an approximately cylindrical shape with a hollow interior. FIG. 2(a) is a perspective view showing the weight 3 and the outer periphery guide 6 in a schematic manner. FIG. 2(b) is a diagram showing a plan view of an example of the weight 3 and the outer periphery guide 6. FIGS. 2(c) and (d) are diagrams showing plan views of another example of the weight 3 and the outer periphery guide 6. As shown in FIG. 2(c), the outer periphery guide 6 may be provided with a convex portion protruding in the inner diameter direction of the outer periphery guide 6. Also, as shown in FIG. 2(d), the weight 3 may be provided with a concave portion having a shape corresponding to the convex portion of the outer periphery guide 6. Also, as shown in FIG. 2(b), the convex portion and the concave portion may not be provided.

The shaft guide 7 is inserted into a hole provided in the axial direction of the weight 3. The case 5 houses the piezoelectric element 2, the weight 3, and the guide 4 inside. The case 5 has, for example, a hollow, approximately cylindrical shape to match the external shape of the weight 3. The upper and lower ends of the shaft guide 7 are fixed to the upper and lower ends of the case 5. The sensor 1 also has a weight 8 for holding the case 5. The weight 8 has, for example, a flat, approximately disc shape, and is provided on the case 5. Note that the guide 4 may be only one of the outer periphery guide 6 and the shaft guide 7.

In the sensor 1, the case 5 is in close contact with the ground of the road to be measured, and the weight 3 is in a floating state, so it can move independently. However, a guide 4 is provided so that the sensor 1 does not tilt relative to the ground and the weight 3 moves vertically (up and down).

This configuration allows the sensor unit to move in accordance with the ground without bolting the sensor 1 to the ground, and the weight 3 is hardly constrained by anything. As a result, when the ground vibrates, the piezoelectric element 2 is compressed between the ground and the weight 3, which tends to stay in place due to the law of inertia, and the piezoelectric element 2 efficiently generates a voltage.

Second Embodiment
FIG. 3 is a diagram showing a sensor 101 according to a second embodiment of the present invention. The sensor 101 according to the second embodiment is different from the sensor 1 according to the first embodiment shown in FIG. 1 in that an adjustment mechanism 9 is added. The adjustment mechanism 9 is for adjusting the angle with respect to the measurement target. The adjustment mechanism 9 has an adjustment bar 10, a support portion 11, and a cone portion 12. The adjustment bar 10 extends substantially parallel (horizontally) to the measurement target (ground) and swings from the substantially parallel state. The adjustment bar 10 supports the outer periphery of the case 10. The support portion 11 supports the adjustment bar 10. The support portion 11 extends in the axial direction (vertically) of the weight 3. The support portion 11 is located outside the case 5. The cone portion 12 is located below the case 5 and is a portion that contacts the measurement target. The cone portion 12 is formed, for example, in a substantially conical shape or a substantially triangular pyramid shape. In addition, the sensor 101 is provided with a bubble level 13 on the upper part of the weight 3.

Figure 4 shows the sensitivity characteristics of the sensor 101. Figure 4(a) shows the case where the cone portion 12 is provided, and Figure 4(b) shows the case where the cone portion 12 is not provided. As shown in the figure, even if the cone portion 12 is provided, the sensitivity does not deteriorate, and it is possible to respond to, for example, a sloped ground surface.

As described above, in this embodiment, a guide 4 is provided to guide the sliding of the weight 3 arranged alongside the piezoelectric element 2. Therefore, when the measurement object vibrates, the piezoelectric element 2 is compressed between the measurement object and the weight 3, which tends to stay in place due to the law of inertia, and the measurement object, and a voltage is generated efficiently by the piezoelectric element 2. This eliminates the need to fix the sensor 1, 101 to the measurement object by staking or the like, and allows measurements to be easily performed without damaging the measurement object.

In addition, in this embodiment, the weight 3 is not fixed. In other words, the weight 3 is in a floating state. This allows the weight 3 to be in a state where there is almost nothing restraining it.

In the sensor 1 according to the first embodiment, if the sidewalk or road on which the sensor 1 is placed is inclined (for example, in Japan, the maximum inclination of a sidewalk is 8 degrees), is not flat, or has bumps and grooves, there is a problem that the sensor 1 cannot be brought into close contact with the ground. In the second embodiment, the sensor 101 is provided with an adjustment mechanism 9 for adjusting the angle with respect to the object to be measured. This allows the sensor 101 to be brought into close contact with the object to be measured even if the object to be measured is inclined, is not flat, or has bumps and grooves.

In the second embodiment, the adjustment mechanism 9 has an adjustment bar 10 that extends substantially parallel to the object to be measured and swings from substantially parallel. This allows the angle of the sensor 101 relative to the object to be measured to be adjusted.

Third Embodiment
5 is a diagram showing a sensor 101 according to the third embodiment. In the third embodiment, the support portion 11 is expandable and contractible, so that the sliding direction of the weight 3 can be adjusted to be the same direction as gravity, and the sensor can be adapted to a slope.

Although the embodiments of the present invention have been described above, the forms to which the present invention can be applied are not limited to the above-mentioned embodiments, and appropriate modifications can be made without departing from the spirit of the present invention.

The present invention can be suitably used in sensors that detect vibrations.

1, 101 Sensor 2 Piezo element 3 Weight 4 Guide 5 Case 6 Outer periphery guide (first guide)
7 Axis guide (second guide)
8: weight 9: adjustment mechanism 10: adjustment bar 11: support portion 12: weight portion 13: bubble level

Claims (16)

A detection element;
A weight arranged next to the detection element;
A guide for guiding the sliding of the weight;
Equipped with
The sensor is characterized in that the weight is in contact with the detection element when the sensor is in a position in which the alignment direction of the detection element and the weight coincides with the direction of gravity . The sensor according to claim 1, characterized in that the weight is not fixed. The sensor according to claim 1 or 2, characterized in that the guide surrounds the outer periphery of the weight. The sensor according to claim 3, characterized in that the guide is provided with a protrusion that protrudes in the direction of the inner diameter of the guide. The sensor according to claim 4, characterized in that the weight has a recess having a shape corresponding to the protrusion. The sensor according to claim 1 or 2, characterized in that the guide is inserted into a hole provided in the axial direction of the weight. The guide is
A first guide surrounding an outer periphery of the weight;
A second guide is inserted into a hole provided in the axial direction of the weight;
3. The sensor according to claim 1, further comprising: The sensor according to any one of claims 1 to 7, further comprising a case that houses the detection element, the weight, and the guide. The sensor according to any one of claims 1 to 8, characterized in that the weight is substantially cylindrical. The sensor further includes a case that accommodates the detection element, the weight, and the guide therein,
10. The sensor according to claim 9, wherein the case has a generally hollow cylindrical shape. The sensor according to claim 8 or 10, further comprising a weight for holding the case. The sensor according to any one of claims 1 to 11, further comprising an adjustment mechanism for adjusting the angle relative to the measurement target. The sensor according to claim 12, characterized in that the adjustment mechanism has an adjustment bar that extends approximately parallel to the object to be measured and swings from approximately parallel. The sensor according to claim 13, characterized in that the adjustment mechanism further has a support part that supports the adjustment bar. The sensor according to claim 13 or 14, characterized in that the adjustment mechanism has a cone portion formed in a roughly cone shape in the portion that contacts the measurement object. The sensor according to any one of claims 1 to 15, characterized in that the detection element is a piezoelectric element.

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