JP3194078B2 - Vibration detector with spontaneous power supply - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a spontaneous power supply,
For example, the present invention relates to a vibration detecting device such as a bearing of a rotary machine.

[0002]

2. Description of the Related Art A bearing or the like of a rotary machine which wears and deteriorates when used, the stop or breakage of the rotary machine due to the progress of wear may cause a serious accident. In the case of a bearing of a rotary machine or the like, vibration increases as wear progresses. Therefore, conventionally, a small vibrometer or the like for detecting this vibration is mounted on a bearing of the rotary machine to detect and display abnormal vibration.

In the simplified vibration monitoring device disclosed in Japanese Patent Publication No. 3-37130, in addition to a vibration detection circuit, a level discrimination circuit, a display circuit, and a storage battery (battery) for supplying power to these circuits, the power is turned on and off. This is a device in which a switch circuit that continuously performs cutoff at a predetermined cycle is integrally configured. Further, in the simple vibration monitoring device, a normal level, a caution level,
The danger level is indicated by three colored lights for easy identification.

[0004] The functions required of the vibration monitoring device with a built-in battery as described above are such that the operation of a patrol worker who patrols the device is not required, and the consumption of the built-in battery is reduced as much as possible. It is to extend the life of the battery. To reduce the consumption of this battery,
In the embodiment disclosed in the above-mentioned patent publication, a switch circuit for continuously turning on and off the power supply in a cycle in which the power supply time to the apparatus is 0.5 seconds and the cutoff time is 5 seconds is provided.

[0005]

In the above-described vibration detecting device with a built-in battery, no matter how the method of reducing the consumption of the battery is adopted, the life of the battery is lost after a certain period of time. For example, it becomes impossible to detect vibrations or display abnormal vibrations at all, and thus it is necessary to replace batteries in all devices before the battery life is exhausted. Furthermore, if the user does not notice the consumption of the battery (drop of output voltage or current) and forgets to replace it, no alarm is displayed even if abnormal vibration occurs, and the equipment to be detected is erroneously determined to be normal. There was a problem that there was a risk of being judged.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and can supply a sufficient power to each circuit in the vibration detecting device, and does not need to consider the life of the power supply. Constantly monitor the state of the bearings, etc.
It is an object of the present invention to provide a vibration detecting device capable of reliably detecting and displaying abnormal vibration generated when the wear and deterioration occur.

[0007]

According to the present invention, there is provided a vibration detecting apparatus using a spontaneous power supply, an acceleration detecting means for outputting a detection signal corresponding to the acceleration of vibration, and a reference signal having a predetermined output level. Level determining means for generating an output when a level is exceeded, display means for displaying the output of the level determining means, and piezoelectric element power generating means using a piezoelectric element for generating electric charge when subjected to vibration in the vibration detecting device according to the spontaneous power supply with a DC converter for converting generated electric charges of the piezoelectric element power generating means to the DC power supply, the piezoelectric element power generating means, it
The piezoelectric element is layered on one or both sides of the rectangular diaphragm
Having first and second rectangular plate-like member, one end of the first rectangular plate-like member is fixed to the vibration detecting device case, said
The other end of the first rectangular plate is the second rectangular plate
Is connected in a U-shape via a spacer and a spacer, and the second
The weight is attached to a predetermined position of the rectangular plate-like member or to a changeable installation. The vibration frequency of a rotating machine or the like that adjusts the mounting position of the weight mounted on the free end side of the rectangular plate member having the U-shaped cantilever structure in the piezoelectric element power generation means of the present invention and detects the natural frequency of the weight. The amount of generated electric charge can be maximized by making the value of. Furthermore, U
Mounting position of the weight in a small space due to the cantilever structure
The variable range is widened, and the variable range of the natural frequency is
Expanded. Therefore, various settings such as a rotating machine that performs acceleration detection
Even if the equipment is vibrating at various vibration frequencies,
The natural frequency of the U-shaped plate to the vibration frequency of
Adjustment is easy, and this adjustment maximizes the amount of generated charge.
Can be. The weight is reduced by the length of the U-shaped beam.
As a result, the durability of the vibration mechanism can be improved.

[0008]

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 is an explanatory diagram of a vibration detecting apparatus using a spontaneous power supply according to the present invention. In FIG. 3, reference numeral 1 denotes a bearing of a rotary machine as a vibration source, 2 denotes a piezoelectric acceleration sensor, and 3 denotes a level determiner, which includes an amplifier 8, a comparator 9, and a multivibrator 10. 4 is a light emitting diode, 5 is a piezoelectric element power generation unit, 6 is a DC converter,
7 is a current limiting resistor. In FIG. 3, a piezoelectric acceleration sensor 2 is attached to a bearing 1 which is a vibration source, and its detection output is supplied to a level discriminator 3. The level determiner 3 lights or blinks the light emitting diode 4 when the output level of the piezoelectric acceleration sensor 2 becomes higher than a preset reference level.

The piezoelectric element power generation unit 5 generates an AC charge by the vibration of the bearing 1, similarly to the piezoelectric acceleration sensor 2, and converts the generated AC charge into a DC voltage by the DC conversion unit 6. The voltage is supplied as the power consumption of the level determiner 3. The current flowing through the light emitting diode 4 is supplied from the level determiner 3 via the current limiting resistor 7. In addition, since the vibration acceleration when the bearing is slightly deteriorated and the vibration is slightly increased is usually about 0.3 G or more, in the present invention, the amount of electric charge generated by the piezoelectric element power generation unit 5 by the vibration acceleration of this degree is used. In order to sufficiently cover the entire power consumption of the vibration detection device, the resonance frequency of the vibration mechanism (in this example, a rectangular plate-shaped or U-shaped plate-shaped cantilever structure) in the piezoelectric element power generation unit 5 is determined by acceleration detection. It has an adjusting means for matching the vibration frequency of the rotating machine or the like, which will be described later.

The level determiner 3 includes an amplifier 8, a comparator 9, and a multivibrator 10, amplifies the output signal of the acceleration sensor 2 corresponding to the vibration acceleration of the bearing, and inputs the amplified signal to one of the comparators 9. Comparator 9
The other input is given a preset reference value, and the reference value is compared with the output value of the amplifier 8 to determine the magnitude relationship between the two signal values. The reference value for comparison can be set to an arbitrary value. When the bearing vibration is normal, that is, when the output of the acceleration sensor 2 is small, the reference value is set to be larger than the output value of the amplifier 8. It is.

Further, when the bearing wears and deteriorates and the vibration increases, the output value of the amplifier 8 becomes larger than the reference value, so that the output of the comparator 9 becomes High level,
The multivibrator 10 is operated. The multivibrator 10 generates a pulse voltage only once every four seconds, for example, for a short time, and supplies a current to the light emitting diode 4 through the current limiting resistor 7 to light the light emitting diode. Can be found at A method for reducing the average current flowing through the light emitting diode 4 will be described later.

Embodiment 1 1A and 1B are diagrams illustrating a first embodiment of a piezoelectric element power generation unit according to the present invention. FIG. 1A illustrates an example of the structure of a cantilever, and FIG. 1B illustrates an example of a weight having a plurality of weights. Is shown. In FIG. 1A, first, rectangular plate-like voltage elements 11A and 11B each having electrodes formed on both sides of a rectangular diaphragm 12 made of phosphor bronze or the like.
Then, one end of the rectangular plate-like member is fixed to a frame 16 with an adhesive 17 such as an epoxy resin, also serving as insulation, to form a cantilever structure. Then, for example, a weight 14 having an opening as shown in FIG. 1B is inserted and attached from the free end of the rectangular plate-shaped member, and this attachment position is at an arbitrary position moved on the member. It can be fixed by the weight position fixing screw 15.

As the weight 14, a plurality of weights having different weights are prepared in advance as shown in FIG. 1B, and a desired weight is selected and used, or the number of weights is reduced. 1
The number is changed to 2, 3, and used as a desired weight. When the weight is metal, the piezoelectric elements 11A, 11B
The contact portion between the electrode and the weight 14 is electrically insulated. For example, it may be insulated by coating with a resin or the like.

As shown in FIG. 1A, one end of a rectangular plate-like member is fixed to a frame 16, and a weight 14
When the vibration mechanism of the cantilever to which is attached is subjected to vertical vibration via the frame 16, the voltage elements 11A,
11B generates an electric charge by bending vibration as indicated by a broken line.
The generated charges are taken out by the lead wires 18A and 18B, and these two outputs are connected to a DC converter 6 after being connected in series or in parallel. Here, FIG.
The two piezoelectric elements 11A and 11B are
In the case of a structure bonded to the front and back of
The plate-shaped piezoelectric elements 11A, 11A are caused by vertical bending vibration.
When one of B is stretched, the other is compressed and deformed in the opposite direction to generate electric charges, so that electric charges are generated twice as much as a single piezoelectric element. Element). The two piezoelectric elements 1
There are two methods for extracting generated charges 1A and 11B as described above. In general, a series connection is used when a high voltage output is desired, and a parallel connection is used when a large current output is desired. Further, by providing the vibration plate 12 between the two piezoelectric elements 11A and 11B, the attachment of the piezoelectric element is facilitated and the mechanical strength of the vibration mechanism is increased.

In the piezoelectric vibrating element having the cantilever structure, the larger the flexural vibration, the larger the amount of generated electric charge. Therefore, it is desirable to obtain as large a flexural amplitude as possible by the vibration. The deflection amplitude in the cantilever vibration mechanism has the maximum value when its natural frequency matches the vibration frequency of the object to be detected, that is, the equipment in which the vibration detection device of the present invention is installed. In (a), the weight 1
By adjusting the mounting position of 4 and its weight, the natural frequency of the rectangular plate-shaped member is made to match the vibration frequency of a rotating machine or the like for detecting acceleration. Note that the vibration frequency band of a rotating machine or the like is usually 10 to 100H.
Since it is about z, a desired natural frequency in the vibration frequency band can be obtained by adjusting the mounting position and weight of the weight 14. By the above adjustment, the two piezoelectric elements 11A and 11B can generate the maximum amount of electric charge.

Embodiment 2 FIG. FIG. 2 is a diagram illustrating Embodiment 2 of a piezoelectric element power generation unit according to the present invention.
A two-story structure is shown in which two diaphragms 12 and 13 each having a piezoelectric element layered on both surfaces thereof are connected in a U-shape using spacers 19. In FIG. 2, a structure in which one end (the left end in the figure) of a first (lower) rectangular plate member having piezoelectric elements 11 </ b> A and 11 </ b> B laminated on both surfaces of a diaphragm 12 is fixed to a frame 16 with an adhesive 17 is illustrated. It is the same as (a) of No. 1. Then, a second (upper) rectangular plate-like member in which the piezoelectric elements 11C and 11D are layered on both surfaces of the vibration plate 13 having a somewhat shorter length than the vibration plate 12 is manufactured, and one end of the second rectangular plate-like member is formed. The other end (the right end in the figure) of the first rectangular plate-shaped member is connected in a U-shape via a spacer 19. Then, a weight 14 having an opening as shown in FIG. 1B is inserted from the free end of the second rectangular plate-like member, and is moved on the above member to a desired position by a weight position fixing screw 15. Fix it. It should be noted that the weight 14 can be increased or decreased or replaced with a weight having a different weight, and that the weight 14 is electrically insulated from the electrodes of the piezoelectric elements 11C and 11D, as shown in FIG. Same as case.

The characteristics of the voltage element power generation section having the structure shown in FIG. 2 are as follows. (1) While the number of piezoelectric elements shown in FIG. 1A is two, the amount of generated charges is almost twice that of FIG. 1 because of the structure having four piezoelectric elements. The four piezoelectric elements 11A to 1A
Since each output of 1D can be taken out from the individual lead wires 18A to 18D, if all the outputs of the four piezoelectric elements are taken out in parallel connection, a current output four times as large as that of one element can be obtained. If the serially connected one is further connected in parallel and taken out, both voltage and current can be output as twice as one element, and if all four outputs are connected in series and taken out, the voltage output four times as large as one element can be obtained. can get. (2) In the structure of FIG. 2, the length of the cantilever
Since it is bent into a letter shape so that it can be stored in a small space, the weight of the weight 14 can be made lighter than in the case of FIG. 1 by the length of the beam. By reducing the weight of the weight 14, the durability of the vibration mechanism is improved, and the life of the piezoelectric element power generation unit can be extended. (3) In addition, since the cantilever beam is lengthened and bent into a U-shape, the weight 14 in a small space is reduced.
The variable range of the mounting position is widened, and the variable adjustment range of the resonance frequency is expanded. Therefore, it becomes easy to match the resonance frequency of the U-shaped plate member to the vibration frequency of a rotating machine or the like that fluctuates over a wide range, and as a result, sufficient power supply required by the vibration detection device can be generated even at ordinary vibration acceleration. it can.

FIG. 4 is a circuit diagram showing an example of a DC converter according to the present invention. The DC converter is composed of four full-wave rectifier diodes and a smoothing capacitor. I do. Then, this DC output voltage is supplied to the level determiner 3.

Next, the power consumption of the level determiner 3 will be described. First, a lighting method of the light emitting diode 4 which accounts for a large proportion of the power consumption will be described. Lighting of the light emitting diode can be visually recognized by repeated lighting of the pulse. For example, if a high brightness type light emitting diode is used, 1 m
If you turn on the current of A for 10 ms, you can check it visually.
If this is turned on once every 4 seconds, the average current will be 2.5 μA. In order to minimize the power consumption of the circuit elements in the level determiner 3, for example, a very low current consumption C-MOS operational amplifier (for example, MAX406 manufactured by Maxim Corporation) is used for the amplifier 8 and the comparator 9, and the multivibrator 10 is a C-MOS. If the MOS logic IC outputs a pulse having a pulse width of 10 ms and a period of 4 seconds, the level determiner 3 can be configured with a known circuit with low power consumption.

In the level judgment device having the above structure, for example, when the supply voltage is set to 3 V DC and the light emitting diode is turned on once every four seconds.
The average value of the total current consumption of the vibration detection device when the light is on for only ms is about 7 to 8 μA. Therefore, even if the light emitting diode 4 is turned on when an alarm occurs, the power consumption of the level determiner 3 is 3 V DC and the current is about 10 μA. It is only necessary to supply power.

As an embodiment of the piezoelectric element power generator 5 having the structure shown in FIG. 2, PZT (lead zirconate titanate) is used for the piezoelectric elements 11A to 11D, and a phosphor bronze plate is used for the vibrating plates 12 and 13. Sensitivity of several thousand nC (nano Coulomb) / G is obtained.
V, and a power supply of 10 μA can be sufficiently supplied. The vibration acceleration when the vibration is increased due to the wear deterioration of the bearing is usually about 1 G. Therefore, if the vibration acceleration is increased, more sufficient power can be supplied.

FIG. 5 is a view showing an example of the structure of a vibration detecting apparatus using a spontaneous power supply according to the present invention. The vibration detecting device shown in FIG. 5 has a structure in which the entire case 20 is vibrated by being fixed to a bearing with a mounting screw provided at the bottom of the case (usually made of metal) 20. In the case, the acceleration sensor 2 and the piezoelectric element power generation unit (in this example, having the structure shown in FIG. 2) 5 are fixed to the case 20, respectively, and further in the case, the level determination unit 3 and the DC conversion unit 6 Is accommodated, and the light emitting diode 4 is mounted thereon. Accordingly, when the bearing wears and deteriorates, the vibration increases, and a signal larger than a preset value is input to the comparator 9 in the level determiner 3, the vibration generated by the piezoelectric element power generation unit 5 by the vibration is used as a power supply to detect the vibration. Since the light emitting diode provided on the upper part of the device case 20 is turned on, the wear deterioration of the bearing can be visually detected. The illustration of the wiring between the devices in the case 20 in FIG. 5 is omitted.

Further, a reference level (generally called a threshold) for the comparator 9 in the level judging device 3 to perform abnormality detection by comparing with the vibration detection level can be set arbitrarily.
If this reference level is set so that the light-emitting diodes light up at the initial stage when the bearings wear and abnormal vibrations begin to occur, the bearings can be checked only by a simple inspection operation to visually check whether the light-emitting diodes are lit. Can be found at an early stage, thereby preventing the occurrence of a serious failure due to the progress of wear deterioration. Further, in the above embodiment, an example in which only one comparison reference value is provided is shown, so that the result of the level determination is normal (good) or abnormal (bad).
However, the present invention is not limited thereto. For example, if two comparison reference values having different values and two comparators are provided, and the level is determined individually, three states of normal, caution, and abnormality can be determined, and as a result, three different colors can be determined. The three states can be displayed separately by the light emitting diode.

Although the deterioration such as wear gradually progresses, the accompanying abnormal vibration does not always increase in proportion to the degree of wear. Therefore, a timer for inputting the abnormality detection signal of the comparator 9 into the level judgment device 3 and holding the same for, for example, 24 hours is provided. If the multivibrator 10 is driven by the output signal of the timer, the acceleration If the vibration exceeds a certain level, the light emitting diode will remain lit for 24 hours and can be found without overlooking the occurrence of wear deterioration, for example, only by visual check once a day.

[0026]

As described above, according to the present invention, various adjustments can be made only by changing the length of the vibrating arm by adjusting the mounting position of the weight attached to the U-shaped plate member in the piezoelectric element power generation means. It can be installed in response to various detection target equipment vibrating at the vibration frequency. Since the U-shaped plate-shaped member, the mounting position variable range of the weight in the small space becomes wider, with a variable adjustment range of the natural frequency is enlarged, and the weight of the weight amount corresponding to the long arm in a U-shape Thus, the durability of the vibration mechanism can be improved.

[Brief description of the drawings]

FIG. 1 is a first embodiment of a piezoelectric element power generation unit according to the present invention.
FIG.

FIG. 2 is a second embodiment of a piezoelectric element power generation unit according to the present invention.
FIG.

FIG. 3 is an explanatory diagram of a vibration detection device using a spontaneous power supply according to the present invention.

FIG. 4 is a circuit diagram illustrating an example of a DC converter according to the present invention.

FIG. 5 is a diagram showing a structural example of a vibration detection device using a spontaneous power supply according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bearing 2 Piezoelectric acceleration sensor 3 Level determiner 4 Light emitting diode 5 Piezoelectric element power generation part 6 DC conversion part 7 Current limiting resistor 8 Amplifier 9 Comparator 10 Multivibrator 11A-11D Piezoelectric element 12, 13 Vibration plate 14 Weight 15 Weight position Fixing screw 16 Frame 17 Adhesive 18A-18D Lead wire 19 Spacer

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hidehiro Inaba 2320-11 Yamamiya, Fujinomiya City, Shizuoka Prefecture Inside Fuji Ceramics Co., Ltd. (56) References JP-A-7-107752 (JP, A) JP-A-62-264920 (JP, A) JP-A-3-60035 (JP, U) JP-A-35-21490 (JP, Y1) ( 58) Field surveyed (Int. Cl. ⁷ , DB name) G01H 11/08

Claims (1)

(57) [Claims] An acceleration detecting means for outputting a detection signal corresponding to a vibration acceleration; a level judging means for generating an output when an output level of the acceleration detecting means exceeds a preset reference level; Display means for displaying the output of the level determining means, piezoelectric element power generating means using a piezoelectric element which generates electric charge when subjected to vibration, and converting the electric charge generated by the piezoelectric element power generating means into a DC power supply The piezoelectric element power generation means comprises a first and a second rectangular plate-like member having a piezoelectric element laminated on one or both sides of a rectangular diaphragm. One end of the first rectangular plate-shaped member is fixed to the vibration detecting device case, and the other end of the first rectangular plate-shaped member is connected to one end of the second rectangular plate-shaped member via a spacer. Is connected to the U-shape, the vibration detecting device according to the spontaneous power, characterized in that the weight is attached to a predetermined position or change freely the installation position of the second rectangular plate member.