JPH0338670Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a piezoelectric pressure gauge for measuring pressure such as the internal cylinder pressure of an engine. This relates to a piezoelectric shiatsumeter with improved linearity.

[Prior art]

Generally, in a piezoelectric acupressure meter, the piezoelectric element exhibits extremely small changes due to pressure, so hysteresis is reduced by applying a sufficient preload to the element. However, conventionally,
The preload sleeve used in this type of piezoelectric shiatsu gauge is made by milling, so the linearity of the shiatsu gauge's sensitivity changes by a maximum of 0.2%. There was a problem that sufficient performance could not be obtained.

[Summary of the idea]

In view of the above points, the present invention was devised in order to eliminate such drawbacks of the conventional method.The present invention is a piezoelectric type acupressure sensor that significantly improves the linearity of sensitivity by annealing the preloading sleeve of the piezoelectric element. It provides a meter. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

〔Example〕

FIG. 1 is a sectional view of a piezoelectric acupressure meter according to an embodiment of the present invention, and its basic structure is the same as the conventional one. In the figure, 1 is a preload sleeve having a cylindrical shape for applying a preload to the piezoelectric element in order to reduce hysteresis;
This sleeve 1 is made of metal such as stainless steel, and also serves as a case. In this sleeve 1, a temperature-correcting mass bottom 2 made of the same material as the bottom surface 1a, which serves as a pressure receiving section, is inserted at a predetermined distance from the circumferential surface of the bottom surface 1a. On a surface, there are a plurality of piezoelectric elements 3a to 3e made of X-axis cut crystal that convert the pressure from the surface into an electric signal, and a mass for taking out the electric signals of these piezoelectric elements to the outside and for accelerating correction. A piezoelectric element 3f for acceleration correction consisting of an electrode 4 and a perforated crystal with an X-axis cut
are stored in a stacked manner. Piezoelectric elements 3a to 3e stacked on the mass bottom 2,
A cylindrical insulating sheet 5 for electrical insulation is inserted between the electrode 4 and the piezoelectric element 3f and the circumferential surface of the sleeve 1 at predetermined intervals.

Further, a cylindrical bushing member 6 made of metal such as stainless steel is integrally attached to the upper surface opening 1b of the sleeve 1 to close it, and a through hole 7 is formed in the center of the bushing member 6.
However, a predetermined cylindrical space section 8 is provided in the upper part of each of them. A lead wire 9 is connected to the center of the upper surface of the electrode 4, and this lead wire 9 is an insulated wire inserted into the through hole 7 of the bushing member 6 so as to be led to the outside through the piezoelectric element 3f for acceleration correction. Terminal 1 via extraction hole 10a of member 10
1 and pulled out to the outside, the terminal 11 is sealed by an insulator 12 inserted into the cylindrical space 8 of the bushing member 6, and the inside of the bushing member 6 is hermetically sealed. ing.

Note that the piezoelectric elements 3a to 3e having a laminated structure and the acceleration correction piezoelectric element 3f are connected to each other through the electrodes 4, so that the electrodes of the piezoelectric elements 3a to 3e and the acceleration correction piezoelectric element 3f are connected to each other through the electrodes 4 so as to cancel out the charges generated by inertial force due to acceleration. An electric signal corresponding to the pressure converted by each of the piezoelectric elements 3a to 3f is output between a terminal 11 led out from a lead wire 9 connected to the bushing member 6 and the bushing member 6.

That is, in this embodiment, the structure of the piezoelectric acupressure meter is the same as the conventional one, but the feature is that the linearity can be greatly improved by annealing the preload sleeve 1. This is what I found.

Here, the reason why the linearity of the piezoelectric shiatsu gauge improved by annealing the sleeve 1 is unknown, but it could be confirmed by the experimental results shown in FIGS. 2 and 3 by the present inventors.

FIG. 2 shows the linearity characteristics of the piezoelectric acupressure meter according to the present invention in which the sleeve 1 is annealed.
The figures show the linearity characteristics of a conventional piezoelectric acupressure meter in which the sleeve 1 is not annealed. In these figures, the horizontal axis shows the applied force (Kg/cm ² ), and the vertical axis shows the linearity (%). The solid line shows the average linearity value, and the broken line shows the best value. There is. As is clear from Figures 2 and 3, the linearity of the conventional model shown in Figure 3 changes by about 0.2% at most, while the linearity of the model of the present invention shown in Figure 2 changes by about 0.025% at most. There was only a slight change, and we were able to improve linearity by about an order of magnitude.

[Effect of idea]

As explained above, according to the piezoelectric acupressure meter of the present invention, linearity can be greatly improved by using an annealed sleeve as a preload sleeve, so performance can be improved with a simple configuration. It has the effect of improving.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a piezoelectric shiatsu meter according to an embodiment of the present invention, Figure 2 is a linearity characteristic diagram of a piezoelectric shiatsu gauge according to the present invention, and Figure 3 is a linearity characteristic diagram of a conventional piezoelectric shiatsu gauge. be. 1... Sleeve, 2... Mass bottom, 3a~3
f... Piezoelectric element, 4... Electrode, 5... Insulating sheet, 6... Bush member, 7... Through hole, 8...
Cylindrical space part, 9... Lead wire, 10... Insulating member, 11... Terminal, 12... Insulator.

Claims (1)

[Scope of utility model registration request] A piezoelectric acupressure gauge with a laminated structure in which a complex piezoelectric element is housed within a sleeve for applying a preload to the piezoelectric element with a mass bottom for temperature correction interposed therebetween, and the sleeve is composed of an annealed sleeve. A piezoelectric acupressure meter that is characterized by: