JPH0245784Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field of the Present Invention> The present invention relates to a vibration detector that detects vibrations of an object by fixing the vibrations to an object to be measured.

<Prior art> For example, a vibration detector that detects vibrations of a power rotating part of a mechanical device includes a detector body containing a built-in vibration detection element and an electrical signal output cable connected to the detector body. . This electrical signal output cable is connected in a direction perpendicular to the vibration detection axis direction of the detector main body so as not to affect vibration detection.

This type of vibration detector has a screw protruding from one end of the detector body in the direction of the vibration detection axis, and is firmly fixed by screwing this screw hole into the screw hole provided at the vibration detection part of the object whose vibration is being measured. The method is common.

However, in this method of screwing in a screw protruding from the detector body, the detector body must be rotated many times. However, since the electrical signal output cable is directly connected to the detector body in a perpendicular direction, the electrical signal output cable must also be rotated at the same time, which causes the cable to become twisted, which is very inconvenient.

In order to eliminate such inconvenience,
No. 52-115923 proposes a vibration detector in which a through hole is provided in the hollow of the vibration detector body so that it can be fixed to an object to be measured with bolts.

<Problems to be Solved by the Present Invention> However, in the vibration detector of JP-A-52-115923, (a) the tightening force due to bolt tightening is directly applied to the vibration detection element (piezoelectric ceramic). Since this tightening must be performed strongly in order to detect vibrations, there is a risk that cracks may occur in the vibration detection element.

(b) Because the cable is directly connected to the vibration detection element, external noise is transmitted, making highly accurate measurements impossible.

There were other problems.

The present invention aims to provide a vibration detector that solves these problems.

<Means for solving the above problems> In order to solve the above problems, in the vibration detector of the present invention, an annular hollow part 11d is provided in the detector main body 10 so as to surround the outer periphery of the fixing through hole 12. and an annular stepped portion of the cylindrical metal sleeve such that one electrode 16a on the inner peripheral surface of the vibration detection element 16 contacts the cylindrical metal sleeve 19 provided inside the annular hollow portion 11d. The annular vibration detecting element 16 is joined to the annular vibration detecting element 16 such that the lower end surface of the vibration detecting element 16 is in contact with the annular vibration detecting element 16, and the annular stepped portion 17a is attached to the upper inner side of the other electrode 16b on the outer peripheral surface of the annular vibration detecting element 16. The annular load mass 17 is joined so that the inner circumferential surface of the annular metal load mass 17 provided in the vibration detection element 16 comes into contact with the inner circumferential surface of the annular load mass 17, and the annular stepped portion 17a contacts only the outer side of the upper end surface of the vibration detection element 16. The metal sleeve 19 and the load mass 17 are electrically connected to the cable 30 inserted into the annular hollow part 11d by a flexible lead wire in the annular hollow part 11d. It is characterized by

<Operation> Because of this structure, the vibration detector of the present invention has the following effects:
Even when the object to be measured is bolted and fixed in the fixing through hole 12, no pressure is applied to the vibration detection element 16. Further, since the cable 30 is connected by a flexible lead wire in the annular hollow portion 11d, external noise is not transmitted.

<Embodiments of the present invention> Examples of the embodiments shown in the drawings will be described below.

FIG. 2 is a sectional view showing an embodiment of the present invention.

In the figure, 10 is a cylindrical detector main body, 30
is an electrical signal output cable directly connected in a direction perpendicular to the vibration detection axis of the detector main body 10.

Reference numeral 11 denotes a bottomed cylindrical metal case of the detector main body 10, which is provided with a fixing through hole 12 in the vibration detection axis direction (that is, perpendicular to the bottom surface 11a) at the center of the bottom plate 11a. Cylindrical inner tube 11
b is erected. The outer peripheral surface of the free end of the inner cylinder 11b is provided with threads 15 for screwing and tightening the lid 14.
is provided.

The cylindrical outer tube 11c has a receiving tube 13 projecting vertically into which the end of the electric signal output cable 30 is inserted, and is provided with an insertion opening 13a on its central axis.

A ring-shaped voltage ceramic element 16 as a vibration detection element and a ring-shaped metal load mass 17 are installed in the annular hollow part 11d formed between the outer cylinder 11c and the inner cylinder 11b, and the fixing through hole 12 is connected to the ring-shaped voltage ceramic element 16 as a vibration detection element. It is arranged coaxially with the fixing through hole 12 so as to surround it.

That is, a cylindrical insulating sleeve 18 is fitted on the outer circumferential surface of the inner cylinder 11b, and a cylindrical metal sleeve 19 is further fitted on the outer circumferential surface of this insulating sleeve 18. This metal sleeve 19 has an annular stepped portion 19a on its lower outer peripheral surface.

The piezoelectric ceramic element 16 is a shear type piezoelectric ceramic element that has a ring shape with a polarization axis in the direction of the arrow, and has electrodes 16a and 16b plated on two inner and outer surfaces parallel to the polarization axis.

This piezoelectric ceramic element 16 has an inner circumferential surface that contacts the metal sleeve 19, and an inner lower end surface of the piezoelectric ceramic element 16 that contacts the electrodes 16a and 16b of the piezoelectric ceramic element 16.
The metal sleeve 19 is placed on the annular stepped portion 19a of the metal sleeve 19 in an annular manner while maintaining an electrically insulating distance from the metal sleeve 19.

Then, on the outer peripheral surface side of the piezoelectric ceramic element 16, a metal load mass 17 having an annular stepped portion 17a on the inner side of the upper end is mounted, and its inner peripheral surface is sheathed to the outer peripheral surface of the piezoelectric ceramic element 16, and the annular Stepped portion 17
A is placed on the outer side of the upper end surface of the piezoelectric ceramic element 16 so as to be mounted in an annular manner while maintaining an electrically insulating distance from the electrodes 16a and 16b.

Electrodes 16a and 1 of piezoelectric ceramic element 16
6b, the outer circumferential surface of the metal sleeve 19 and the inner circumferential surface of the metal load mass 17 that are bonded thereto are bonded and fixed together with, for example, adhesive, while maintaining electrical contact. There is.

Due to this configuration, the vibration of the detector main body 10 in the vibration detection axis direction causes the metal load mass 17 to follow, and as a result, the piezoelectric ceramic element 16 undergoes mechanical shearing in the direction of the polarization axis shown by the arrow. When a load is applied, a shear-type vibration sensing element is established and produces a voltage output proportional to the acceleration of the vibration.

A cylindrical insulating sleeve 20 is attached to the inner circumferential surface of the outer cylinder 11c, and a cylindrical sleeve 21 is further attached to the inner circumferential surface of the insulating sleeve 20.

The insulating sleeve 20 and the sleeve 21 are
Openings 20a, 21 for inserting the electrical signal output cable 30 into positions corresponding to the insertion holes 13a of No. 3.
a.

The sleeve 21 includes an annular step 21b, and an annular relay plate 22 is mounted and fixed on the annular step 21b.

The relay plate 22 has a partial electrode surface 22 on a part of the upper surface.
It is made of an insulating plate plated with A, and is provided with a lead wire insertion hole 22b at the position of the partial electrode surface 22a.

In FIG. 2, 23 is an annular insulating plate glued to the bottom surface of the case 11, and 24 is an annular insulating plate glued to the bottom surface of the lid 14. The vibration detection element consisting of the load mass 17 and the case 11 are insulated, thereby creating an electrically insulating structure and an external noise shielding structure.

The lid 14 has an annular shape, has a thread 14b on the inner circumferential surface of a hole 14a in the center, and has an annular stepped portion 14c provided externally at its upper end.

Reference numeral 25 denotes an O-ring placed on an annular step 11e provided at the upper end of the outer cylinder 11c of the case 11, and the thread 14b of the lid 14 is aligned with the thread 15 of the inner cylinder 11b.
By screwing and tightening the O-ring 25, the O-ring 25 is compressed between the annular step portion 11e and the annular step portion 14c.
A sealing structure is established between d and the outside. Furthermore, in order to obtain a more complete sealing effect, the lid 14
Between the threads 14b and the threads 15 of the inner cylinder 11b,
For example, they are screwed together using an adhesive or the like. In addition, the lid 14
Two blind holes 14d and 14e provided on the top surface of the
is used for tightening the lid 14.

Insertion port 13a of receiver tube 13 and insulation sleeve 2
0. One end of the electrical signal output cable 30 is inserted through the openings 20a and 21a of the sleeve 21 into the hollow portion 11d of the case 11.

Shield image 30a of electrical signal output cable 30
is soldered to the metal sleeve 19 which is in contact with the internal electrode 16a of the piezoelectric ceramic element 16. Core wire 30b of electrical signal output cable 30
is soldered to the partial electrode surface 22a of the relay plate 22. One end of a lead wire 31 is soldered to the partial electrode 22a through the lead wire insertion hole 22b, and the other end of the lead wire 31 is soldered to the upper surface of the metal load mass 17.
The lead wire 31 is made of a soft and thin lead wire that does not exert a mechanical load upon vibration detection by the piezoelectric ceramic element 16.

A rubber tube 32, a presser 33, a rubber ring 34, and a fastener 35 are inserted into one end of the electrical signal output cable 30 in this order.

The fastener 35 has a thread 3 on its inner end that is threaded into a thread 13b provided on the inner peripheral surface of the free end of the receiving part 13.
5a. Therefore, the threads 3 of the fastener 35
5a and the thread 13b of the receiving tube 13, the rubber tube 32 and the rubber ring 34 are strongly pressed against the electric signal output cable 30 within the receiving tube 13 via the presser 33, This establishes a seal structure.

In the vibration detector according to this embodiment, in order to detect vibrations, a bolt 42 is inserted into the fixing through hole 12 of the detector main body 1, as shown in FIG. Screw hole 41 provided in the part
The tip of the bolt 42 is screwed into the inside of the detection body 10 to tighten and fix the detection body 10 to the object 40 whose vibration is to be measured.

As shown in FIG. 4, at the end (on the bottom 11a side) of the through hole 12, a thread 26 is provided on the inner circumferential surface for screwing with a bolt from the side of the object whose vibration is to be measured. Good too.

<Effects of the present invention> Since the vibration detector of the present invention is configured as described above, (a) Even if the object to be measured is bolted and fixed to the object to be measured in the fixing through hole 12, the vibration detector does not exist in the annular hollow portion 11d. Since no pressure is applied to the vibration detecting element 16, there is no fear of cracks occurring in the vibration detecting element 16 as in the conventional case.

(b) Since the cable 30 is connected by a flexible lead wire in the annular hollow portion 11d, external noise is not transmitted, allowing highly accurate measurement.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the invention, Fig. 2 is a front view showing its fixed state, Fig. 3 is a sectional view showing another embodiment of the invention, and Fig. 4 is its fixed state. FIG. 10...Detector body, 11...Case, 11b
... Inner cylinder, 11c ... Outer cylinder, 11d ... Annular hollow part, 12 ... Fixing through hole, 13 ... Receiving cylinder, 1
6...Piezoelectric ceramic (vibration detection element), 17...
...Annular load mass, 19...Metal sleeve, 22
... Relay board, 23 ... Insulation board, 24 ... Insulation board,
30... Cable, 40... Vibrating object to be measured.

Claims (1)

[Claims for Utility Model Registration] Detector body 10 with built-in vibration detection element 16
The detector main body 10 has a fixing through hole 12 in a direction parallel to the vibration detection axis at the center of the detector body 10 in a direction parallel to the vibration detection axis.
and a cable 30 connected in a perpendicular direction, the detector body 10 is provided with an annular hollow part 11d so as to surround the outer periphery of the fixing through hole 12, and the inside of the annular hollow part 11d is provided. One electrode 16a on the inner peripheral surface of the vibration detecting element 16 is in contact with the cylindrical metal sleeve 19 provided at The annular vibration detecting element 16 is joined so that the end surfaces thereof are in contact with each other, and the other electrode 16b on the outer peripheral surface of the annular vibration detecting element 16 is provided with a metal annular load having an annular stepped portion 17a inside the upper end. An annular load mass 17 is joined and inserted into the annular hollow part 11d so that the inner peripheral surface of the mass 17 contacts and the annular step part 17a contacts only the outer side of the upper end surface of the vibration detection element 16. A vibration detector characterized in that the metal sleeve 19 and the load mass 17 are electrically connected to the cable 30 in the annular hollow portion 11d by a flexible lead wire.