JP2867103B2 - Vibration meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrometer, and more particularly to a vibration meter for measuring the amount of vibration of the machine in an operating state for the purpose of maintenance and failure diagnosis of the machine. It is suitable for application to a vibrometer which is used by pressing against a vibration measurement surface of an object. More specifically, among vibrometers including an accelerometer, a speedometer, a displacement meter, and the like, the present invention is particularly suitable for application to an accelerometer. Therefore, the description will be made mainly based on an accelerometer (vibrometer).

[0002]

2. Description of the Related Art Conventionally, when a vibrometer is classified according to a direction in which vibration is sensed, a single-axis vibrometer having only a single sensitive axis and a three-axis vibrometer can be used.
It can be divided into a three-axis vibrometer having a direction sensitive axis. Also, depending on the method of use, the vibration meter can be used by fixing the vibration meter to the object to be measured using screws or adhesives, or a fixed type that can be used by the measurer while holding it by hand It can be classified into a pressing type which is used by pressing and fixing by pressing against an object.

In general, all of these vibrometers have a contact surface (or pressing portion) with respect to a vibration measuring surface of the vibrometer and a spring constant between the vibration measuring surfaces (hereinafter referred to as a contact spring constant).
The size of the vibration sensor and the mass of the vibration sensor substantially determine the measurement area where the vibrometer can measure. That is, the relationship between the vibration of the vibration measurement surface and the sensitivity of the vibration sensor (hereinafter referred to as frequency characteristics) is shown in FIG. 11 when sensitivity is taken on the vertical axis and frequency on the vibration measurement surface is taken on the horizontal axis. Usually, in a vibration measurement, a vibration frequency f1 (hereinafter, referred to as a contact resonance frequency) between the vibration meter and the vibration measurement surface generated according to the magnitude of the contact spring constant and the mass of the vibration sensor in the vibration measurement. ) _Is used as the measurement data.

In this case, for example, if the vibration sensor 1 shown in FIG. 12A and the vibration sensor 2 shown in FIG. Is horizontal to the vibration measurement surface 3 as shown by an arrow a in FIG. 12A, and the sensitive axis K1 of the vibration sensor 1 attached to the vibration measurement surface 3 is As shown by an arrow b in FIG.
FIG. 13 shows a comparison between frequency characteristics when the sensing axis K2 of the vibration sensor 2 attached to the vibration measurement surface 3 is perpendicular to the vibration measurement surface 3 and the vibration sensor 2 is perpendicular to the vibration measurement surface 3. Next, the contact resonance frequency f _a under the condition of FIG.
Is lower than the contact resonance frequency f _b under conditions of FIG. 12 (B).

The contact resonance frequencies f _a and f _b are determined by the vibration direction of the vibration measurement surface 3 and the direction of the sensitive axis K 1 or K 2 of the vibration meter 1 or 2 attached to the vibration measurement surface 3. The cause of the difference is that the vibration sensors 1 and 2
This is because the contact spring constant between the vibration measurement surface 3 and the vibration measurement surface 3 differs depending on the vibration direction. In general, a vibration sensor has its sensitive axis perpendicular to the vibration measurement surface and the vibration measurement object. The contact spring constant when the vibration direction is also perpendicular to the vibration measurement surface is better when the sensitive axis is parallel to the vibration measurement surface and the vibration direction of the vibration measurement object is also parallel to the vibration measurement surface. It can be said that it is larger than the contact spring constant.

Further, in a vibration meter, a fixed type vibration meter is fixed to a vibration measurement object by a surface, whereas a pressing type vibration meter generally has a probe tip of 3 to 10 [m].
m], and comes into contact with the vibration measurement surface in a state close to point contact, and is usually used with a pressing force of about 1 to 2 [Kg weight]. Therefore, the contact-type vibrometer has a smaller contact spring constant due to a smaller contact area with the vibration measurement surface than the fixed-type vibrometer, and thus has a problem of lower contact resonance frequency. However, the vibration meter of the pressing type can measure the vibration amount just by pressing against the vibration measuring surface.
For example, when measuring many measurement points continuously, it is easier and more effective to measure than a fixed vibrometer. It is suitable for measuring the amount of vibration of

Conventionally, in this type of measurement,
The amount of vibration in the direction perpendicular to the measurement surface of the vibration measurement object (hereinafter, this direction is referred to as the Z-axis direction), and any two directions parallel to the measurement surface and perpendicular to each other (hereinafter, this direction is the X-axis direction) And the Y-axis direction) are measured, and the vibration state of the vibration measurement object is three-dimensionally analyzed based on the obtained measurement results. In general, the inspection method in this case is one for each of a point on a plane orthogonal to the X-axis direction, one point on a plane orthogonal to the Y-axis direction, and one point on a plane orthogonal to the Z-axis direction. In this method, a total of three one-axis vibrometers are fixed or pressed.

However, in such an inspection method, the inspection efficiency is poor, and since the measurement points for the vibrations in the respective axial directions are not the same, it cannot be said that the measurement of the vibration at one desired location is strictly performed. There is a problem that only a rough vibration measurement result of the object to be measured can be obtained. As one means for solving this problem, a fixed type three-axis vibrometer 10 having a structure as shown in FIG. 14 has been conventionally proposed.

That is, in the three-axis vibrometer 10, the sensing axes K10, K11 and K12 are respectively attached to three adjacent sides 11A, 11B and 11C of the vibration sensor mounting block 11 formed in a substantially rectangular parallelepiped shape. 11A-11
Vibration sensors 12A, 12B to be perpendicular to C
And 12C are provided, respectively, and the side surface 11D opposite to the mounting surface 11A of the vibration sensor 12A used for measuring the vibration in the Z-axis direction is attached to the vibration measuring surface of the measurement object (not shown) with an adhesive or By fixing using screws or the like, vibrations in three axial directions of the X-axis direction, the Y-axis direction, and the Z-axis direction can be simultaneously detected at one place.

[0010]

However, in the vibration meter 10 of this type, when it is fixed to the vibration measurement surface by using a screw or the like, vibration in a direction perpendicular to the vibration measurement surface (Z-axis direction) is not affected. The contact resonance frequency is high because the contact spring constant is large, and thus the vibration frequency range in the Z-axis direction that can be measured by the vibration sensor 12A is widened, whereas the vibration measurement surface is horizontal (in the X-axis direction and the X-axis direction). Z for vibration in the Y-axis direction)
The contact spring constant is lower than the contact spring constant in the axial direction, so that the contact resonance frequency is reduced, so that the vibration sensors 12B and 12C can measure in the X-axis direction and the Y-axis.
The vibration region in the axial direction becomes narrow. For this reason, this type of vibrometer 10 has a problem that the frequency range in the X-axis direction and the Y-axis direction obtained as a measurement result is only about one fifth of the frequency range in the Z-axis direction. Even when the conventional fixed-type three-axis vibrometer 10 is gripped by hand and pressed against the vibration measurement object, the vibration can be compared with the case where the vibrometer 10 is fixed to the vibration measurement surface with a screw or the like. The frequency range in which the X-axis direction and the Y-axis direction can be measured is further narrowed.

Further, a probe is attached to the conventional three-axis vibrometer 10, and a vibrometer (not shown) configured to measure by pressing the tip of the probe against a vibration measurement object while holding the probe by hand. ) Can be considered, but since the tip of the probe is formed in a spherical surface and comes into contact with the vibration measurement surface in a state close to point contact, the three-axis vibrometer 10 shown in FIG. Compared to the case of using by holding and pressing, the contact spring constants in the X-axis direction and the Y-axis direction can obtain only small values. Therefore, flat vibration characteristics cannot be obtained up to a frequency range of 2 [KHz] or more required for equipment diagnosis, and a practical pressing type three-axis vibrometer has not yet been realized.

The present invention has been made in consideration of the above points, and it is possible to simultaneously measure vibration amounts in three directions perpendicular to each other at one place, and to increase the contact resonance frequency at this time to a high frequency region. It is intended to propose a vibrometer that can be obtained.

[0013]

According to the present invention, there is provided a vibrometer which is used by pressing against a vibration measuring surface of a vibration measuring object in one direction in each of sensitive axes K30 to K32 and K33. ~ K36, and the sensitive axis K
A plurality of vibration sensors 32A to 32C, 32D to 32 which detect the amounts of vibration in the directions 30 to K32 and K33 to K36 and output the detection signals S1 to S3 and S10 to S13, respectively.
G and a plurality of vibration sensors 32A to 3
2C, the equal angle theta ₂ about respective predetermined central axis M ₂ a 32D～32G, and the sensitive axis K30～K32,
K33~K36 is Pushing part 31A pressed against the vibration measurement face of the respective central axes M ₂ and the vibration measuring object, a vibration sensor holding means 31 and 51 for fixing and holding to intersect at a point U ₂ on the surface of 51A, Detection signals S1 to S3, S
Arithmetic means 41A to 41C and 41D to 41 for respectively calculating the amounts of vibration in two or three axes orthogonal to each other at the vibration measurement position of the vibration measurement object based on 10 to S13.
F.

[0014]

[Function] A plurality of vibration sensors 32A to 32C, 32D to 3
2G are equiangular θ about a predetermined central axis M _2.
2, and the sensitive axis K30～K32, so K33~K36 intersect in the center axis M ₂ and Pushing portion 31A pressed against the vibration measuring surface of the vibrating object to be measured, a point U ₂ on the surface of 51A fixed While holding, the detection signals S1 to S3,
The respective vibration sensors 32A to 32C and 32D to 32G are configured to calculate the amount of vibration in the two-axis or three-axis directions orthogonal to each other at the vibration measurement position of the vibration measurement target based on S10 to S13. Vibration including a biaxial or triaxial vibration component as a constant can be detected up to a high contact resonance frequency, and thus the vibration amounts in two axial directions or three axial directions perpendicular to each other at the vibration measurement position can be simultaneously detected at one place. And a vibrometer capable of increasing the contact resonance frequency f1 to a high frequency region at this time can be realized.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

(1) Principle of Operation In general, when a bar having a sharp tip is pressed vertically against a surface vibrating in the horizontal direction (hereinafter referred to as a horizontal vibration surface), the bar has a horizontal tip. Vibrates together with the vibrating surface. This movement is caused by the point of the rod member in contact with the horizontal vibration surface at a point on the center axis of the rod member (hereinafter, this point is referred to as a fulcrum).
It is the same as oscillating on an arc centered at. Here, as shown in FIG. 1 (A), the rod member (not shown) the central axis M ₁ each of the first and second vibrating sensor element and point S and point T is in the position of the line symmetrical about the (not shown) to oscillate integrally with said rod member, and consider the vibration pickup 20 each sensitive axis K20 and K21 are arranged so as to intersect at a predetermined point R on the center axis M _1.

When the tip point U ₁ of the vibration pickup 20 is pressed vertically against the horizontal vibration surface 21, the first and second points
The vibration sensor element vibrates in the horizontal direction by vibration (hereinafter, referred to as direct vibration) received from the horizontal vibration surface 21 via the rod member. At this time the first and second vibrating sensor element, as shown in FIG. 1 (B), by moving to the rod member is tilted a predetermined point P on the center axis M ₁ as a fulcrum, around the intersection H of the central axis M ₁ lines and rod member passing through the point S and T points to a so-called Rotsukingu movement. In this case, the direct vibration received by the first and second vibration sensor elements from the parallel vibration surface 21 and the vibration based on the rocking motion (hereinafter referred to as rocking vibration) are in phase, and accordingly the first and second vibration sensor elements are accordingly. From the respective vibration sensor elements, an output based on the direct vibration and an output based on the rocking vibration are combined and output.

[0018] Here, for example, as shown in FIG. 2, the straight line passing through the straight line passing through the fulcrum P and center point U ₁ of the fulcrum P of the rod member as the origin Z axis, orthogonal vital point S and T points with the Z axis Is defined as the Y axis, and the Z coordinates of the intersection H, the point R, and the end point U ₁ at this time are Z _H , Z _R, and Z, respectively.
And _U, and the Y coordinate of the point T and Y _T. When the center point U ₁ when the vibration pickup 20 is to vibrate with an acceleration in a direction parallel to the Y-axis α indicated by the arrow c, the second vibration sensor elements arranged in the point T is Y axis direction and the Z-axis direction Vibration is detected at the same time.

In this case, the output P _T of the second vibration sensor element is such that the horizontal vibration amount of the second vibration sensor element is y, the vertical vibration amount is z, and the sensitivity of the second vibration sensor element is axis K21 following equation angle formed between the center axis M ₁ bar members (hereinafter referred to as cross angle) as theta ₁

(Equation 1) Given by When center point U ₁ at this time the vibration pickup 20 and the oscillation angle of the fulcrum P of when moving in the acceleration α in the Y-axis direction [delta], the following equation

(Equation 2) Accordingly, the horizontal vibration amount y and the vertical vibration amount z of the second vibration sensor element are respectively expressed by the following expressions.

(Equation 3)

(Equation 4) It can be expressed as.

Accordingly, by substituting equations (3) and (4) for y and z in equation (1), the output _PT of the second vibration sensor element is given by the following equation.

(Equation 5) Can be transformed as follows. At this time, the Z coordinate Z _H of the intersection H is calculated using the Z coordinate Z _R of the point R as

(Equation 6) Therefore, the expression (6) can be expressed as (5)
By substituting into the equation, the output P of the second vibration sensor element is obtained.
_T is

(Equation 7) And then, by substituting equation (2) into equation (7), equation (7) becomes

(Equation 8) Can be transformed as follows.

As is apparent from the equation (8), the output _PT of the second vibration sensor element is equal to the sensitive axis K21 of the second vibration sensor element and the center axis M _{1 of the} rod member (ie, It depends on the intersection angle θ ₁ of the perpendicular line of the parallel vibration plane) and the position of the fulcrum P. In this case, the crossing angle θ ₁ can be mechanically adjusted, but the fulcrum P cannot always be fixed to one point in a wide frequency range.

However, the following equation

(Equation 9) As in, when to match the intersection R between the center axis M ₁ of the sensitive axis K21 and bar member of the second oscillation sensor element at the tip point U ₁ of the vibration pickup 21, the second vibration sensor elements Is the output _PT

(Equation 10) As is apparent from the expressed and, without depending on the position of the fulcrum P, consequently it exhibits the same output as when attached to the distal end point U _1. In this case, the output of the first vibration sensor element and the output of the second vibration sensor element are such that the horizontal vibration has the opposite phase and the direction perpendicular to the parallel vibration surface 21 has the same phase. By taking the difference between the outputs of the second vibration sensor elements, the amount of horizontal vibration applied to the first and second vibration sensor elements can be detected, and
By taking the sum of the outputs of the first and second vibration sensor elements, the amount of vibration applied to the first and second vibration sensor elements in a direction perpendicular to the parallel vibration surface 21 can be detected.

(2) First Embodiment In FIG. 3, reference numeral 30 denotes a three-axis accelerometer as a whole, and an acceleration sensor mounting block 31 which is formed in a substantially conical shape as a whole by using a rigid base material such as a metal. The vertex 31A is formed in a spherical shape. As is clear from FIGS. 3 and 4, the bottom surface portion 31B of the acceleration sensor mounting block 31 has a substantially slight height except for the mounting portions 31BX of the first to third acceleration sensors 32A to 32C formed in a planar shape. is formed in a truncated cone shape of the upper surface thereof an extension of the bar-shaped handle 33 is the central axis M ₂ is (referred to as vibration measurement point U ₂ this below) tip U ₂ of the top portion 31A in the surface and the bottom surface portion 31B Are arranged so as to pass through the center point C of the upper surface.

In this case, each of the acceleration sensors 32A to 32C is constituted by using a piezoelectric element.
３２32C have their sensing axes K30〜K32 at the vibration measurement point U _2.
At an equal angle β [°] so as to intersect at a predetermined angle θ ₂ which is equal to the extension of the central axis M ₂ of the handle 33 at
(Β = 120 °). Thus, in the three-axis acceleration meter 30, by pressing the vibration measurement point U ₂ while gripping the handle 33 by hand vibration measurement surface of the measurement object (not shown), among the vibration measurement surface vibration It has been made so as to measure the amount of vibration at the measuring point U ₂ is pressed against position.

[0025] In this case in the three-axis acceleration meter 30, vibration measurement to face direction (Z axis direction) perpendicular extension of the center axis M ₂ of the handle 33 relative to the measurement surface of the vibration measurement object when pressed against the point U _2, the direction extending to the center position of the first acceleration sensor 32A from the Z-axis as a Y-axis direction, the measurement surface is X-axis direction in contact with the vibration measurement point U _2, Y-axis direction, and In the Z-axis direction,

[Equation 11]

(Equation 12)

(Equation 13) Assuming that the first and third acceleration sensors 32A to 32C vibrate at an acceleration represented by

[Equation 14]

(Equation 15)

(Equation 16) The vibration amount represented by is detected.

The first to third acceleration sensors 32A to 32A-3
2C is the following formula for vibration in the Y-axis direction.

[Equation 17]

(Equation 18)

[Equation 19] The amount of vibration represented by

(Equation 20)

(Equation 21)

(Equation 22) The vibration amount represented by is detected.

Accordingly, each of the first to third acceleration sensors 32A
-32C are obtained from the equations (11)-(22) as a whole as follows:

(Equation 23)

(Equation 24)

(Equation 25) Vibrations in represented by detecting from the measurement surface in contact vibration measurement point U _2. In this case, as shown in FIG. 5, the first acceleration sensor 32A converts the detection result into a detection signal S1 and supplies it to the first and third arithmetic circuits 41A and 41C via the charge amplification circuit 40A. The second and third acceleration sensors 32B and 32C output the detection results as a detection signal S2, respectively.
And S3, and supplies it to all the first to third arithmetic circuits 41A to 41C via the charge amplification circuit 40B or 40C.

At this time, the following equation is obtained.

(Equation 26) And the following equation

[Equation 27] Is used to calculate β in Expressions (23), (24) and (25).
Substituting [°] gives

[Equation 28]

(Equation 29)

[Equation 30] As shown in (1), unnecessary terms are cancelled, and an equation including only equations representing vibrations in the X-axis direction, the Y-axis direction, and the Z-axis direction as unknowns can be derived.

Accordingly, in the X-axis direction at a point on the vibration measurement surface where the vibration measurement point U ₂ of the three-axis accelerometer 30 contacts,
The vibrations in the Y-axis direction and the Z-axis direction are obtained by solving the equations (28), (29) and (30) for the equations representing the vibrations in the X-axis direction, the Y-axis direction and the Z-axis direction, respectively.

(Equation 31)

(Equation 32)

[Equation 33] Can be calculated by

Thus, the arithmetic circuits 41A to 41C determine the amounts of vibration in the X-axis direction and the Y-axis direction based on the detection signals S1 to S3 according to the arithmetic expressions shown in the equations (31), (32) and (33), respectively. And the amount of vibration in the Z-axis direction are calculated, and the calculation results are amplified and then output as operation signals S4 to S6. In the case of this embodiment, the acceleration sensor 32A
Angle sensitive axis K30~K32 of ~32C is intersecting the extension line of the center axis M ₂ of the handle 33 in the vibration measurement point U ₂ theta
₂ is selected at an angle of about 10 ° to 45 ° from experimental data.

[0031] In the above configuration, in the three-axis acceleration meter 30, the acceleration sensor by pressing the vibration measurement point U ₂ of the acceleration sensor mounting block 31 relative to the vibration measurement face of the vibration measurement object 32A~32C Detects the vibration acceleration of the measurement surface, and outputs the detection signals S1 to S3.
Is supplied to predetermined arithmetic circuits 41A to 41C. Each arithmetic circuit 41A~41C executes predetermined arithmetic processing on the basis of the detection signal S1 to S3, which by the X-axis direction at the position pressed against vibration measurement point U ₂ of the measuring surface of the vibration measurement object, Y The amount of vibration in the axial direction or the Z-axis direction is calculated.

FIG. 6 shows each acceleration sensor 32 of the embodiment.
FIG. 7 shows the vertical and horizontal frequency characteristics of the acceleration sensors A to 32C, and FIG. 7 shows the directivity of the acceleration sensors 32A to 32C in the Y-axis direction. One of the important elements of the normal vibration pickup is the contact resonance frequency. For example, in the case of the acceleration type vibration pickup, as described above, the frequency of one third of the contact resonance frequency is generally regarded as a flat area and the measurement data is measured. Used for Therefore, the higher the contact resonance frequency, the wider the measurement range.

In this case, the contact resonance frequency is determined by the mass and the contact spring constant. For example, as shown in FIG. 14, each of the sensitive axes K10 to K12 is a fixed type 3-axis vibrometer 10 orthogonal to each other. In this case, since the spring constant in the horizontal direction is smaller than the spring constant in the vertical direction, the contact resonance frequency in the horizontal direction is one fifth of that in the vertical direction.
It was about. However, in the three-axis accelerometer 30 of the embodiment, the horizontal contact resonance frequency is 5.3 [KHz] and the vertical contact resonance frequency is 3.5 [KHz]. It was confirmed that the resonance frequency was higher than the vertical contact resonance frequency.

This is because the horizontal contact spring constant of the three-axis accelerometer 30 is as small as that of the fixed three-axis vibrometer 10, but the dynamic effective mass is further reduced. It can be assumed that this is because the contact resonance frequency in the horizontal direction is increased. Practically this type of 3-axis accelerometer 3
0, the acceleration sensor mounting block 3 in the vertical direction
All 1's are dynamic masses, but in the horizontal direction the mass is proportional to the force required to tilt them, and the apparent dynamic mass is a small value. This tendency becomes more remarkable as the tip becomes thinner or longer. Therefore, in the three-axis accelerometer 30, the apparent dynamic mass in the horizontal direction can be reduced by making the tip thinner and longer, and thus the horizontal direction can be reduced. Is considered to be able to increase the contact resonance frequency.

According to an experiment, when a conventional fixed-type three-axis accelerometer 30 as shown in FIG. While the contact resonance frequency is in a very low frequency region with the pressing force of the above, in the case of the three-axis accelerometer 30, for example, the contact resonance frequency is reduced with a pressing force of about 1 [Kg]. It has been found that it is possible to measure up to a sufficiently high vibration region for practical use.

According to [0036] above configuration, the first to third acceleration sensor 32A to 32C, around the extension line of the center axis M ₂ of the handle 33 on the inclined surface of the bottom portion 31B of the acceleration sensor mounting block 31, respectively at equal intervals of an angle beta, and thereby arranged to intersect at equal crossing angle theta ₂ in the central axis extension and vibration measurement point U ₂ of M _2, the arithmetic circuit 41A~41C from the acceleration sensors 32A~32C Based on the supplied detection signals S1, S2, and / or S3, the X-axis direction and the Y-axis parallel to the measurement surface of the object to be measured are calculated according to the equations (31), (32), and (33), respectively. The first to third acceleration sensors 32A to 32C calculate the vibration measurement point U ₂ with a high contact spring constant by calculating the vibration amount in the direction and the vibration amount in the Z-axis direction perpendicular to the measurement surface.
At the same time, vibrations including horizontal and vertical vibration components are detected, and detection signals S1 to S3 are obtained by canceling unnecessary terms based on equations (28), (29) and (30).
, The amount of vibration in each of the three axial directions can be calculated.
A pressing-type three-axis accelerometer capable of simultaneously measuring the amount of vibration in the axial direction at one place and increasing the contact resonance frequency f1 at this time to a high frequency region can be realized.

In addition, since the vibration measurement at one point can measure the vibration in three axes, the behavior analysis of three axes due to the vibration in a physically narrow range can be performed. Furthermore, the ability to easily measure the vibrations of one point in three axial directions at the same time makes it possible to measure the relative vibrations of three axes, thus grasping the three-dimensional movement, and providing a closer contact between the vibration and the actual state. Can understand the correlation. Furthermore, the ability to easily measure vibrations at one point in three axial directions simultaneously facilitates the development of a vibrometer that effectively displays the three-dimensional vibration state and the development of equipment such as frequency analysis of vibration waveforms with the maximum amplitude. Thus, the field of application of vibration measurement in the future can be greatly expanded.

Further, since the vibration of one point in three axial directions can be easily measured at the same time, so-called modal analysis, which is an analysis of vibration by signal processing of a computer which requires labor, can be easily performed. Can be. Further, the first to third acceleration sensors 32A to 32C detect the vibration on the measurement surface of the vibration measurement object, and transmit these as detection signals S1 to S3 to the arithmetic circuits 41A to 41C via the charge amplification circuits 40A to 40C. At the same time, the arithmetic circuits 41A to 41C determine the X-axis direction, the Y-axis direction, and the Z-axis direction based on the detection signals S1 to S3 according to the arithmetic expressions shown in Expressions (31), (32), and (33), respectively. By calculating the amount of vibration, the vibration measurement point U ₂ is adjusted by adjusting the pressing angle of the three-axis vibration meter 30 with respect to the measurement surface.
Can detect vibration amounts in desired three directions orthogonal to each other.

In this case, each of the acceleration sensors 32A to 32C
The vibration of the central axis M ₂ direction of the handle 33 and detects a vibration in the Z-axis direction, a direction toward the first acceleration sensor 32A on the vibration measurement point U ₂ and as the Z-axis plane perpendicular Y Detected as axial vibration.

(3) Second Embodiment FIG. 8 in which parts corresponding to those in FIG. 3 and FIG.
And FIG. 9 shows a three-axis accelerometer 5 according to a second embodiment of the present invention.
0, the acceleration sensor mounting block 51 has substantially the same external configuration as the acceleration sensor mounting block 31 of the three-axis accelerometer 30 described above with reference to FIGS. 3 and 4 except for the arrangement of the acceleration sensors 32D to 32G. . That is, in the three-axis accelerometer 50, as is clear from FIG. 8, the fourth to seventh acceleration sensors 32D similar to the first to third acceleration sensors 32A to 32C (FIGS. 3 and 4).
32G are the sensitive axes K33 to K36 are the vibration measurement points U ₃ at the tip of the top 51A of the acceleration sensor mounting block 51.
As intersect at the central axis M ₂ of extension and each equal angle theta ₂ of the handle 33 in the acceleration sensor attachment portion 5 of the bottom portion 51B of the acceleration sensor mounting block 51
1BX are arranged at equal intervals of an angle γ (γ = 90 [°]).

[0041] In accordance connexion the 3-axis acceleration meter 50, the central axis M ₂ vibration measurement object wheel 33 vibration measuring point U ₃ perpendicular to the measurement surface (not shown) on the measuring surface when pressed against the direction from the central axis M ₂ to the center position of the fourth acceleration sensor 32D as a Y-axis direction, X-axis direction from the central axis M ₂ to the center position of the fifth acceleration sensor 32E As the direction, the vibration measurement point U ₃
Assuming that the measurement surface that makes contact with vibrates in formulas (11), (12), and (13) in the X-axis direction, the Y-axis direction, and the Z-axis direction, respectively, Acceleration sensor 32D
~ 32G is the following formula for vibration in the X-axis direction

(Equation 34)

(Equation 35)

[Equation 36]

(37) The vibration component of the vibration amount shown in FIG.

The fourth to seventh acceleration sensors 32D to 32D
32G is the following formula for vibration in the Y-axis direction, respectively.

(38)

[Equation 39]

(Equation 40)

[Equation 41] The vibration component of the vibration amount shown in the following is detected.

(Equation 42)

[Equation 43]

[Equation 44]

[Equation 45] The vibration component of the vibration amount shown in FIG.

Accordingly, the fourth to seventh acceleration sensors 32D to 32D
32G is expressed by the following equations as a whole using equations (34) to (45).

[Equation 46]

[Equation 47]

[Equation 48]

[Equation 49] Vibrations in represented by detecting from the measurement surface in contact vibration measurement point U _3. Here, as shown in FIG. 10, the fourth and sixth acceleration sensors 32D and 32F determine the detection result by the detection signal S.
10 and S12, respectively,
Or 40F to the second and third arithmetic circuits 41E and 41F, and the fifth and seventh acceleration sensors 32E and 32G transmit the detection results to the detection signals S11 and S1.
3 and transmitted to the first and third arithmetic circuits 41D and 41F via the charge amplification circuit 40E or 40G, respectively.

In this case, the following equations are obtained from the equations (46), (47), (48) and (49).

[Equation 50]

(Equation 51)

(Equation 52) As shown in (1), an unnecessary term can be canceled to derive an equation including only equations representing vibration in the X-axis direction, the Y-axis direction, or the Z-axis direction as unknowns. Accordance connexion X-axis direction at a position on the vibration measurement face of the accelerometer 50 vibration measuring object vibration measurement point U ₃ and contacts, Y-axis and Z
The axial vibration is obtained by solving the equations (50), (51) and (52) with respect to the equations representing the vibration in the X-axis direction, the Y-axis direction, or the Z-axis direction, respectively.

(Equation 53)

(Equation 54)

[Equation 55] Can be calculated by

Thus, the arithmetic circuits 41D to 41F determine the X-axis direction and the Y-axis direction in accordance with the arithmetic expressions (53), (54) and (55) based on the detection signals S10, S11, S12 and / or S13, respectively. The amount of vibration in the axial direction and the Z-axis direction is calculated, and the calculation result is output as operation signals S14 to S16.

[0046] In the above configuration, in the three-axis acceleration meter 50, the acceleration sensor 32D~32F by pressing the vibration measurement point U ₃ of the acceleration sensor mounting block 51 relative to the measurement surface of the vibration measurement object The vibration acceleration of the measurement surface is detected, and this is detected as detection signals S10 to S13.
Is supplied to predetermined arithmetic circuits 41D to 41F. Each arithmetic circuit 41D~41F executes predetermined arithmetic processing on the basis of the detection signal S10 to S13, thus X-axis direction at the position pressed against vibration measurement point U ₃ of the measuring surface of the vibration measurement object, Y-axis The amount of vibration in the direction or the Z-axis direction is calculated.

According to the above configuration, the three-axis accelerometer 50 is different from the three-axis accelerometer 30 of the first embodiment in vibration in the X-axis direction, the Y-axis direction, and the Z-axis direction. Since the vibration amount is detected by many acceleration sensors 32D to 32F or 32G one by one, it is possible to realize a vibrometer capable of measuring the vibration amounts in three axial directions with higher sensitivity.

(4) Other Embodiments In the first and second embodiments described above, the present invention is applied to a third embodiment.
The case where the present invention is applied to the shaft accelerometers 30 and 50 has been described, but the present invention is not limited to this, and can be applied to various vibration meters such as a displacement meter and a speedometer.

In the first and second embodiments, the case where the acceleration sensor mounting blocks 31 and 51 are formed in a substantially conical shape using a rigid base material such as a metal has been described. The invention is not limited to the above, but has a predetermined stiffness, and each of the acceleration sensors 32A to 32C or 32D to 3D
As long as the 2G can be maintained in a predetermined state, various other substrates and shapes can be applied to the acceleration sensor mounting blocks 31 and 51.

Further, in the first and second embodiments described above, the plurality of acceleration sensors 32A to 32C or 32D to 32D
By arranging 32G on the slope surface of the bottom surface 31A or 51A of the acceleration sensor mounting block 31 or 51, each of the acceleration sensors 32A to 32C or 32D to 32 is provided.
It has dealt with the case of equal distance to the vibration measurement point U ₂ or U ₃ from G, the present invention is not limited to this, the acceleration sensors 32A~32C or 32D~32G
The sensitive axis K30~K32 or K33~K36 the central axis M ₂ of extension as value, if the or each acceleration sensor 32A~32C angle is equal 32D~32G handle 33
The distance to the vibration measurement point U ₂ or U ₃ from may not be equal. Also in this case, the three-axis vibrometer can obtain substantially the same effects as those of the first and second embodiments.

Further, in the above-described first and second embodiments,
Are the acceleration sensors 32A to 32C or 32D to 32G
K30-K32 or K33-K36 are vibration measurement
Point U _TwoOr U_ThreeAt the center axis M of the handle 33_TwoNo
Angle θ intersecting with the long line_TwoIs about 10 ° to 45 °
Although the case where the selection is made to be
Is not limited to this, and the angle θ_TwoIs of other sizes
good.

Further, in the above-described first and second embodiments, the case where the three-axis accelerometers 30 and 50 detect the amount of vibration in three directions perpendicular to each other has been described. However, the vibration meters 30 and 50 may output only the vibration amount in one or two directions among the vibration amounts in three directions perpendicular to each other, and in this case, the vibration meters 30 and 50 may be set to 1 What is necessary is just to use it as an axial or biaxial vibration meter.

Further, in the first and second embodiments described above, the acceleration sensors 32A to 32C or 32D to 32G
Are described on the slope surface of the bottom surface portion 31B or 51A of the acceleration sensor mounting block 31 or 51, but the present invention is not limited to this, and the point is that each acceleration sensor 32A ~ 32C or 32D
Signals S1 to S3 or S10 output from to 32G
If the amount of vibration in the three-axis direction or the two-axis direction can be detected based on S13 to S13, various other values can be applied to the number of acceleration sensors provided in the acceleration sensor mounting block 31 or 51. it can.

Further, in the first and second embodiments described above, each of the arithmetic circuits 41A to 41C or 41D to 41G is calculated by the arithmetic expression (31), (32) and (33) or (53). vibration wherein the X-axis direction, Y axis direction and the Z-axis direction in the measurement plane (54) and (55) vibration measurement object subordinate connexion vibration measurement point U ₂ or U ₃ is in contact with the arithmetic expression shown in equation Although the case of calculating the quantity has been described, the present invention is not limited to this, and the equations (23), (24) and (25) or (46), (47) and (48) Various other arithmetic expressions can be applied as the arithmetic expression for detecting the vibration amount based on the expression.

Further, in the first and second embodiments described above, the case where the acceleration sensors 32A to 32C or 32D to 32G made of piezoelectric elements are used has been described. However, the present invention is not limited to this, and the acceleration sensors 32A to 32C may be used. 32C or 3
As the 2D to 32G, other various types such as a strain vibration sensor or an optical vibration sensor can be applied, and various shapes can be applied.

Further, in the first and second embodiments, the arithmetic circuits 41A to 41C or 41D to 41F
And each of the arithmetic circuits 41A to 41C or 41D to 41F
Described the case where the amount of vibration in the X-axis direction, the Y-axis direction, or the Z-axis direction was calculated. However, the present invention is not limited to this. If present, one or more arithmetic circuits 41A-
41C or 41D to 41F may be used.

[0057]

As described above, according to the present invention, in a vibrometer which is used by pressing against a measurement surface of a vibration measurement object,
A plurality of vibration sensors are fixedly held at equal angles around a predetermined central axis, and each of the sensing axes intersects the central axis at one point on the surface of the pressing portion, and the output of each vibration sensor is By calculating the amount of vibration in the two-axis or three-axis direction at the measurement point of the vibration measurement object based on the vibration sensor, each vibration sensor can use two axes or three axes with a high contact spring constant.
The vibration amounts of the vibration components in the axial direction can be respectively detected, and thus the vibration amounts in two axial directions or three axial directions perpendicular to each other at the vibration measurement position can be simultaneously measured at one place, and the contact resonance frequency at this time Can be increased to a high frequency range.

[Brief description of the drawings]

FIG. 1 is a conceptual schematic diagram for explaining the operation principle of the present invention.

FIG. 2 is a conceptual schematic diagram for explaining the operation principle of the present invention.

FIG. 3 is a side view showing a first embodiment of a three-axis accelerometer according to the present invention.

FIG. 4 is a top view of the three-axis accelerometer shown in FIG.

5 is a block diagram showing a signal processing circuit of the three-axis accelerometer shown in FIG.

FIG. 6 is a characteristic curve diagram showing vertical and horizontal contact resonance frequencies of the three-axis accelerometer according to the embodiment.

FIG. 7 is a characteristic curve diagram showing the directivity in the horizontal direction of the three-axis accelerometer according to the embodiment.

FIG. 8 is a side view showing a second embodiment of the three-axis accelerometer according to the present invention.

9 is a top view of the three-axis accelerometer shown in FIG.

FIG. 10 is a block diagram showing a signal processing circuit of the three-axis accelerometer shown in FIG.

FIG. 11 is a characteristic curve diagram for explaining the relationship between the sensitivity of the acceleration sensor and the vibration frequency.

FIG. 12 is a plan view for explaining a difference in a contact resonance frequency due to a difference in a vibration direction and a direction of a sensing axis of a vibration sensor.

FIG. 13 is a characteristic curve diagram for explaining a difference in a contact resonance frequency due to a difference in a vibration direction and a direction of a sensing axis of a vibration sensor.

FIG. 14 is a schematic perspective view showing a conventional fixed-type three-axis vibrometer.

[Explanation of symbols]

1, 2, 12A to 12C, 32A to 32G: Vibration sensor (acceleration sensor), 10: Vibrometer, 11, 31, 5
1... Vibration sensor holding means (acceleration sensor mounting block), 30, 50... Vibration meter (three-axis accelerometer), 31
A, 51A ... Pressing portion (apex portion), 41A to 41F ...
... Calculation means (calculation circuit), S1 to S3, S10 to S13
............ Detection signals, K1, K2, K10 to K12, K30 to
K36 ...... sensitive axis, M ₂ ...... axis (central axis), U _2, U ₃
…… Point (vibration measurement point), β, γ …… Angle, θ ₂ …… Intersection angle.

Claims (1)

(57) [Claims] 1. A vibrometer which is used by being pressed against a vibration measuring surface of a vibration measuring object, each of which has a sensing axis in one direction, and detects a vibration amount in the sensing axis direction to generate a detection signal as a detection signal. A plurality of vibration sensors to output, having a predetermined stiffness, the plurality of vibration sensors are respectively equiangular about a predetermined center axis, and the sensing axes are respectively the center axis and the vibration measurement object. Vibration sensor holding means for holding fixedly so as to intersect at one point on the surface of the pressing portion for pressing against the vibration measurement surface; and two axes orthogonal to each other at a vibration measurement position of the vibration measurement object based on the detection signal. A vibrometer comprising: calculation means for calculating respective amounts of vibration in three axial directions.