阅读说明：本技术 柔性电极支撑结构 (Flexible electrode supporting structure ) 是由 郜晨希 林琳 王迪 郑旭 刘瑞琪 远雁 李超波 于 2019-11-27 设计创作，主要内容包括：本发明公开了一种柔性电极支撑结构,该柔性电极支撑结构为圆环方波型结构,置于柔性电极外壳台阶处,用于支撑陶瓷定电极,并调节陶瓷定电极与金属动电极之间的电容距离。本发明提出的柔性电极支撑结构采用圆环方波结构,在高精度薄膜传感器中,柔性电极支撑结构作为连接媒介,在温度变化时,通过弹性形变来吸收和释放陶瓷与金属热膨胀系数不同引起的机械迟滞,可以有效避免金属动电极和陶瓷定电极热膨胀系数不同导致的机械迟滞。(The invention discloses a flexible electrode supporting structure which is of a circular ring square wave structure and is arranged at a step of a flexible electrode shell for supporting a ceramic fixed electrode and adjusting the capacitance distance between the ceramic fixed electrode and a metal moving electrode. The flexible electrode supporting structure provided by the invention adopts a circular square wave structure, and in a high-precision film sensor, the flexible electrode supporting structure is used as a connecting medium, so that mechanical hysteresis caused by different thermal expansion coefficients of ceramic and metal is absorbed and released through elastic deformation when the temperature changes, and the mechanical hysteresis caused by different thermal expansion coefficients of a metal moving electrode and a ceramic fixed electrode can be effectively avoided.)

1. The flexible electrode supporting structure is characterized in that the flexible electrode supporting structure is of a circular ring square wave structure, is arranged at the step of a flexible electrode shell and is used for supporting a ceramic fixed electrode and adjusting the capacitance distance between the ceramic fixed electrode and a metal movable electrode.

2. The flexible electrode support structure of claim 1, wherein the flexible electrode support structure is stamped from a low expansion alloy circular ring.

3. The flexible electrode support structure of claim 1, wherein the flexible electrode support structure is fabricated from a nickel-based alloy material.

4. The compliant electrode support structure of claim 1 having a spring rate that is 5 to 10 times greater than the ceramic fixed electrode hold down spring.

5. The flexible electrode support structure of claim 4, wherein the flexible electrode support has a spring rate of 2500 to 5000N/mm.

6. The flexible electrode support structure of claim 1, wherein the ratio of splay to twist of the flexible electrode support structure is greater than 2: 1.

Technical Field

The invention relates to the field of sensors, in particular to a flexible electrode supporting structure.

Background

A capacitive pressure sensor is generally configured using a moving electrode made of a metal diaphragm and a fixed electrode made of an insulating material such as ceramic as a base. The metallic moving electrode and the ceramic fixed electrode are separated by a fixed electrode structure so as to establish capacitance. Although capacitive pressure sensors may be good at securing the fixed electrodes, there may be slight variations in geometry over time, such as changes in temperature. The coefficient of thermal expansion of the metal housing is typically greater than the coefficient of thermal expansion of the ceramic electrode. Thus, heating or cooling the capacitive sensor assembly may generate internal stresses within the assembly, thereby affecting the geometry, in particular the distance between the metal diaphragm and the ceramic fixed electrode. Mechanical stresses can build up to a certain extent during heating or cooling, and when the stresses are sufficiently great, the electrode and the housing can move relative to each other to relieve the stresses. This motion is referred to as "stick-slip" or "mechanical hysteresis". These stick-slip motions affect the geometry and can adversely affect the accuracy of the capacitive sensor assembly, are less repeatable, and cannot be predicted and compensated for. Therefore, it is necessary to design a flexible electrode support for a capacitive pressure sensor, which can improve the electrode gap control at a lower pressure, and prevent mechanical hysteresis such as temperature drift, thereby improving the measurement capability of the pressure sensor at a lower pressure.

Disclosure of Invention

Technical problem to be solved

The invention mainly aims to provide a flexible electrode supporting structure to solve the problem that the distance value between a metal diaphragm and a ceramic fixed electrode is influenced due to mechanical delay caused by different thermal expansion coefficients of the metal moving electrode and the ceramic fixed electrode.

(II) technical scheme

The flexible electrode supporting structure is a circular ring square wave structure, is arranged at the step of a flexible electrode shell and is used for supporting a ceramic fixed electrode and adjusting the capacitance distance between the ceramic fixed electrode and a metal moving electrode.

In the scheme, the flexible electrode supporting structure is formed by stamping the low-expansion alloy circular ring.

In the scheme, the flexible electrode supporting structure is made of a nickel-based alloy material.

In the above scheme, the elastic coefficient of the flexible electrode supporting structure is 5 times to 10 times that of the ceramic fixed electrode compression spring.

In the scheme, the elastic coefficient of the flexible electrode support is 2500N/mm to 5000N/mm.

In the scheme, the unfolding-rotating ratio of the flexible electrode supporting structure is greater than 2: 1.

(III) advantageous effects

1. The flexible electrode supporting structure provided by the invention adopts a circular square wave structure, mechanical hysteresis caused by different thermal expansion coefficients of ceramic and metal is caused due to temperature change in a high-precision film sensor, the flexible electrode supporting structure is used as a connecting medium, and the mechanical hysteresis caused by different thermal expansion coefficients of ceramic and metal is absorbed and released by elastic deformation of the flexible electrode supporting structure when the temperature is changed, so that the mechanical hysteresis caused by different thermal expansion coefficients of a metal moving electrode and a ceramic fixed electrode can be effectively avoided.

2. The flexible electrode supporting structure provided by the invention adjusts the initial flexible supporting distance by adjusting the deformation distance of the fixed electrode compression spring, namely the distance between the fixed electrode and the upper cover of the shell, and as the elastic coefficient of the flexible support is far greater than that of the compression spring, the large deformation of the compression spring can be changed into the small deformation of the flexible support, so that the capacitor distance can be controlled more accurately.

3. The flexible electrode supporting structure provided by the invention adopts a circular square wave structure, and can ensure the balance of the pressure of the first chamber and the pressure of the second chamber.

Drawings

FIG. 1 is a schematic diagram illustrating a method for adjusting capacitance distance in the prior art;

FIG. 2 is a schematic diagram of a capacitive pressure sensor in accordance with an embodiment of the present invention;

FIG. 3 is a flexible electrode support structure according to an embodiment of the invention.

Description of reference numerals: 1: ceramic fixed electrode, 2: ultrathin pad, 3: type I support ring, 4: a housing, 11: first chamber, 12: upper cover, 13: outer shell, 14: ceramic fixed electrode, 15 diaphragm moving electrode, 16: second chamber, 17: flexible electrode support structure, 18: compressing the spring.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to specific embodiments and the accompanying drawings.

As shown in fig. 3, fig. 3 is a schematic diagram of a flexible electrode supporting structure according to an embodiment of the present invention, which is a circular ring square wave structure and is formed by stamping a low expansion alloy circular ring. The flexible support structure is arranged at the step of the shell and used for supporting the ceramic fixed electrode and adjusting the capacitance distance between the ceramic fixed electrode and the metal moving electrode through the flexible support structure.

The position of the flexible electrode supporting structure in the pressure sensor is shown in fig. 2, the flexible electrode supporting structure is made of a metal low-expansion alloy, and the low-expansion alloy is a nickel-based alloy such as GH 3600. The elastic coefficient of the flexible electrode supporting structure is greater than that of the ceramic fixed electrode compression spring, specifically, the elastic coefficient of the flexible electrode support is 2500N/mm to 5000N/mm, and the capacitance distance is obtained by subtracting the deformation distance of the flexible electrode supporting structure from the initial distance of the flexible electrode supporting structure, namely

Wherein d represents the distance between the ceramic fixed electrode and the metal movable electrode, H represents the initial height of the flexible support, and k₁Representing the spring constant, k, of the compression spring of the flexible electrode₂The elastic coefficient of the flexible support is shown, and h represents the compression distance of the compression spring, namely the distance between the fixed electrode and the upper cover. Wherein k is₁Is much greater than K₂Range of ratios thereofThe circumference is 5 times to 10 times, and the purpose is as follows:

after the compression spring is compressed, the flexible support is slightly deformed, and errors caused by the fact that the deformation exceeds the elastic range due to overlarge deformation are avoided;

and (II) because the capacitance is measured with high precision, the smaller the capacitance distance is, the better the capacitance distance is, the distance of the capacitance distance is changed by adjusting the compression distance h of the compression spring.

According to the flexible electrode supporting structure provided by the embodiment of the invention, the unfolding-rotating ratio of the flexible electrode supporting structure is more than 2: 1, and the flexible electrode supporting structure is made of a metal low-expansion alloy material, specifically, a nickel-based alloy such as GH3600, or the same material as a moving electrode or a shell.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.