JPH0524025Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a piezoelectric vibration detector, and in particular, it is attached to a noisy rotating machine, etc., so that it can be used at all times.
The present invention relates to an acceleration type vibration detector for measuring vibration.

[Prior Art] Various proposals have been made to prevent noise in piezoelectric vibration detectors. For example, a low-noise coaxial cable with carbon rubber coated on the inside of the outer shield has been proposed as the output cord of the detector. The one I use is one of them.

Furthermore, when used by attaching it to a rotating machine with a high noise level, the detector body 21 may be attached to the object to be measured 23 via an attachment 22 made of an insulator, as shown in FIG. ing.

Alternatively, a vibration detector with a metal case may be housed as is in a separate metal mounting container, and the metal case and mounting container may be connected via an insulator so that they do not come into contact with each other to reduce noise. be.

[Problems to be solved by the invention] Conventional piezoelectric vibration detectors as described above cannot be used to measure low-level vibrations or in extremely noisy environments such as electrical sparks generated by the opening and closing operations of electrical circuit breakers. When measuring under these conditions, it was not possible to sufficiently prevent measurement disturbances due to noise.

This idea was made to solve the above problem, and the purpose is to obtain a piezoelectric vibration detector that can minimize the influence of disturbance noise even when used in a noisy machine. It is.

[Means for Solving the Problems] The piezoelectric vibration detector according to this invention includes a base and a unit in which an insulating layer is formed by thermal spraying on the contact surface with the upper surface of the base and is fixed to the base with an insulating set screw. A base, a piezoelectric element sandwiched between a pair of insulating plates, and a weight are sequentially stacked on the unit base, and surround the vibration-electric conversion section and the vibration-electric conversion section fixed to the base unit in layers. The unit includes an inner cover that is coupled to the unit base, and an outer cover that surrounds the inner cover and is coupled to the base.

[Function] In this device, a double container consisting of an outer side consisting of a base and an outer cover, and an inner side consisting of a unit base and an inner cover are assembled so as to be electrically insulated from each other. Disturbance noise caused by current is reduced.

[Example] Figures 1 and 2 show an example of this invention,
The base 1 made of metal has a mounting hole 1a for the object to be measured.
is provided, and a receptacle 2 is fixed to the side surface. Further, a screw hole 1b is formed from the top surface of the base 1 to which a set screw 3 is attached, and
An outer cover 4 is screwed in from above. 4a is a lid body. A metal unit base 5 mounted on the upper surface of the base 1 has an insulating layer 5a made of alumina material or the like formed by thermal spraying on the contact surface with the base 1. Two opposing cutout planes 5b are formed on the side surface of the unit base 5, and these two
The unit base 5 is held by a wrench or the like using the surfaces, and then tightened and fixed to the setscrew 3. The set screw 3 is an insulating screw made of synthetic resin or sprayed with alumina.
Further, a screw hole is provided on one side of the plane 5b, and a lug plate (not shown) to which a lead wire is soldered is fixed with a screw. This lead wire is connected to one end of the receptacle 2 and to the outer shield wire of the double shield wire. An electrode 7 is placed in the middle of the center ball screw 6 erected on the upper surface of the unit base 5.
An insulating tube 8 is attached to avoid contact with. The piezoelectric element 9 is sandwiched between a pair of insulating plates 10 and is electrically floating in order to extract signals through separate lead wires. Note that the piezoelectric element 9 is 1
Although it consists of a pair, it may also be one. The piezoelectric element 9, the insulating plate 10, the electrode 7, etc. are tightened with a nut 12 via a weight 11 and fixed in a layered manner to form a vibration-electric conversion section. This layered body consists of an inner cover 13 that is press-fitted into the unit base 5.
surrounded by Epoxy resin 14 is applied to the shaded area.
is filled to firmly connect and fix each part. 15 is an impedance converter including an IC and a resistance element.

Note that the insulating layer 5a on the upper surface of the unit base 5 is
Although a structure with a washer interposed may be used instead of thermal spraying, thermal spraying is advantageous in terms of reducing the number of parts.

[Effects of the invention] As explained above, this invention reduces disturbance noise by housing an inner container consisting of a unit base and an inner cover insulatingly coupled to the base in an outer container consisting of the outer cover of the base. can be significantly reduced.

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional view of one embodiment of this invention;
The figure is a cross-sectional view taken along the line - in FIG. 1, and FIG. 3 is a partial cross-sectional elevational view of how a conventional piezoelectric vibration detector is used. DESCRIPTION OF SYMBOLS 1... Base, 3... Set screw, 4... Outer cover, 5... Unit base, 5a... Insulating layer, 9
... Piezoelectric element, 11 ... Weight, 13 ... Inner cover.

Claims (1)

[Scope of utility model registration request] A unit base has an insulating layer formed by thermal spraying on the contact surface between the base and the upper surface of the base and is fixed to the base with an insulating set screw, and a piezoelectric element and a weight sandwiched between a pair of insulating plates. A vibration-to-electric conversion section which is sequentially stacked on a unit base and fixed to the base unit in a layered manner, an inner cover which surrounds the vibration-to-electric conversion section and is coupled to the unit base, and the inner cover. a piezoelectric vibration detector comprising an outer cover surrounding and coupled to the base.