阅读说明：本技术 一种重力传感器及电子重力仪 (Gravity sensor and electronic gravimeter ) 是由 王斌 陶照明 秦佩 薛振海 李过 赵杰 黄涛 黄雯迪 黄海潮 于 2019-12-19 设计创作，主要内容包括：本发明公开了一种重力传感器及电子重力仪,该重力传感器包括底框,与其连接的摆框,摆框上部连接扭丝,扭丝通过连接杆连接动极板,动极板连接限位块,限位块在限位器调节范围内移动,限位器通过限位器支架与底框连接；上定极板和下定极板平行设置并分别通过极板支架与底框连接,动极板位于上定极板和下定极板两平面之间形成的限位空间内；弹簧一端连接动极板,另一端连接底框；所述扭丝、连接杆、上定极板、下定极板和动极板表面均有导电膜。上述各部件除限位器和限位块外均采用石英材料制作。本发明的重力传感器简化了结构,增强了牢固度与稳定性,实现了电信号的反馈和控制,测量精度高,更适合用于电子重力仪。(The invention discloses a gravity sensor and an electronic gravimeter, wherein the gravity sensor comprises a bottom frame and a swinging frame connected with the bottom frame, wherein the upper part of the swinging frame is connected with a torsion wire, the torsion wire is connected with a movable polar plate through a connecting rod, the movable polar plate is connected with a limiting block, the limiting block moves in the adjusting range of a limiting device, and the limiting device is connected with the bottom frame through a limiting device bracket; the upper fixed polar plate and the lower fixed polar plate are arranged in parallel and are respectively connected with the bottom frame through polar plate supports, and the movable polar plate is positioned in a limiting space formed between two planes of the upper fixed polar plate and the lower fixed polar plate; one end of the spring is connected with the movable polar plate, and the other end of the spring is connected with the bottom frame; and the surfaces of the torsion wire, the connecting rod, the upper fixed polar plate, the lower fixed polar plate and the movable polar plate are all provided with conductive films. All the parts except the limiting stopper and the limiting stopper are made of quartz materials. The gravity sensor of the invention simplifies the structure, enhances the firmness and stability, realizes the feedback and control of electric signals, has high measurement precision, and is more suitable for an electronic gravimeter.)

1. A gravity sensor is characterized by comprising a bottom frame, a swinging frame, a torsion wire, a connecting rod, a spring, an upper fixed polar plate, a lower fixed polar plate, a polar plate bracket, a movable polar plate, a limiting block, a limiting stopper and a limiting stopper bracket; the bottom frame, the swinging frame, the torsion wires, the connecting rods, the springs, the upper fixed polar plates, the lower fixed polar plates, the polar plate supports, the movable polar plates and the limiter supports are made of quartz materials; wherein the content of the first and second substances,

the bottom frame is connected with the swing frame, the upper part of the swing frame is connected with the torsion wire, the torsion wire is connected with the movable polar plate through the connecting rod, the movable polar plate is connected with the limiting block, the limiting block moves in the adjusting range of the limiting block, and the limiting block is connected with the bottom frame through the limiting block support;

the upper fixed polar plate and the lower fixed polar plate are arranged in parallel and are respectively connected with the bottom frame through polar plate supports, and the movable polar plate is positioned in a limiting space formed between two planes of the upper fixed polar plate and the lower fixed polar plate;

one end of the spring is connected with the movable polar plate, and the other end of the spring is connected with the bottom frame;

and the surfaces of the torsion wire, the connecting rod, the upper fixed polar plate, the lower fixed polar plate and the movable polar plate are all provided with conductive films.

2. The gravity sensor according to claim 1, wherein the quartz material has an impurity content below 2 ppm.

3. The gravity sensor according to claim 2, wherein the parts made of quartz material are assembled by welding with an oxyhydrogen flame.

4. The gravity sensor according to claim 1, wherein the cross-sectional diameter of the twisted wire is 30-70 μm.

5. An electronic gravimeter, comprising the gravity sensor according to any one of claims 1-4, wherein the upper fixed plate, the lower fixed plate and the movable plate of the gravity sensor are connected by a conductive cable for signal feedback and signal control.

Technical Field

The invention relates to the technical field of intelligent measurement and control devices, in particular to a gravity sensor and an electronic gravimeter.

Background

The gravimeter is a basic means for geophysical exploration and information observation of the earth gravitational field. The method has wide application in fields such as exploration of energy sources such as oil and gas fields and coal fields, exploration of metal and nonmetal mineral resources, geological disaster observation, measurement of earth gravitational field, solid tide observation, crust deformation observation, earthquake prediction observation and the like; in the aspect of national defense construction, gravity field information is also an extremely important basic material. From the relevant data, the current foreign gravity measurement equipment is mainly used for mineral exploration, volcanic exploration, earthquake prediction and regional gravity research

Through analysis of several relative gravimeters at home and abroad, the performance can be roughly divided into two categories, the first category is a manual measurement mechanical gravimeter and belongs to the first generation product. The second type of gravimeter is an electronic gravimeter. Compared with the new advanced electronic gravimeter, the first generation of equipment lags behind, and has more defects: firstly, the precision is low; secondly, the manual measurement mode has low speed and complex calculation; thirdly, the temperature has a great influence on the equipment. The electronic gravimeter effectively solves the problems that a mechanical gravimeter gravity sensor cannot output digital gravity signals and cannot form electric signal feedback and the like, and also solves the influence of the aspects of temperature, air pressure, arrangement state and the like on detection precision to a certain extent, for example, the high-precision electronic gravimeter disclosed in patent No. 201610305130.5 can detect tiny gravity changes with high sensitivity and high resolution by adopting a data conversion and acquisition system, can realize high-speed (60 numbers/second) full-automatic (automatic acquisition, automatic compensation and automatic storage) data acquisition and processing, and has the detection precision of 10-30 micro gamma.

The core component of the electronic gravimeter is a gravity sensor, and although the current gravity sensor has made certain improvements in use portability and detection accuracy, there still exists room for improvement, such as robustness and stability, structural complexity, measurement accuracy, and the like.

Disclosure of Invention

The invention aims to provide a gravity sensor with simplified structure, enhanced firmness and enhanced stability, which is particularly suitable for an electronic gravimeter.

Another object of the present invention is to provide an electronic gravimeter including the gravity sensor.

The technical scheme of the invention is detailed as follows:

the gravity sensor provided by the invention comprises a bottom frame, a swinging frame, a torsion wire, a connecting rod, a spring, an upper fixed polar plate, a lower fixed polar plate, a polar plate bracket, a movable polar plate, a limiting block, a limiting stopper and a limiting stopper bracket, wherein the swinging frame is arranged on the bottom frame; the bottom frame, the swinging frame, the torsion wires, the connecting rods, the springs, the upper fixed polar plates, the lower fixed polar plates, the polar plate supports, the movable polar plates and the limiter supports are made of quartz materials; wherein the content of the first and second substances,

the bottom frame is connected with the swing frame, the upper part of the swing frame is connected with the torsion wire, the torsion wire is connected with the movable polar plate through the connecting rod, the movable polar plate is connected with the limiting block, the limiting block moves in the adjusting range of the limiting block, and the limiting block is connected with the bottom frame through the limiting block support;

the upper fixed polar plate and the lower fixed polar plate are arranged in parallel and are respectively connected with the bottom frame through polar plate supports, and the movable polar plate is positioned in a limiting space formed between two planes of the upper fixed polar plate and the lower fixed polar plate;

one end of the spring is connected with the movable polar plate, and the other end of the spring is connected with the bottom frame;

and the surfaces of the torsion wire, the connecting rod, the upper fixed polar plate, the lower fixed polar plate and the movable polar plate are all provided with conductive films.

The gravity sensor comprises a set of differential capacitance formed by an upper fixed polar plate, a lower fixed polar plate and a movable polar plate, and an electric signal is transmitted through a conductive film, so that the three capacitor polar plates form the differential capacitance type capacitance micrometer. Only one spring is used, and the movable polar plate is connected with the movable polar plate, so that the movable polar plate is balanced by utilizing the elastic characteristic of the spring, and the structure is simplified. The torsion wire connects the movable polar plate with the swinging frame, and when the movable polar plate moves up and down, the torsion wire immediately twists, and the torsion wire plays a role of a rotating shaft in the whole system. The movable polar plate moves in the adjusting range of the limiter through the limiting block, and the firmness and stability of the sensor are enhanced.

Alternatively or preferably, in the gravity sensor described above, the impurity content of the quartz material is less than 2 ppm. The outstanding advantages of this high-purity quartz material are very low thermal conductivity, excellent resistance to thermal vibrations, very high deformation and softening temperatures, very low thermal conductivity, very low dielectric losses and an extremely broad spectral transmission from ultraviolet to infrared. The gravity sensor is made of the material, so that the stability of sensor parts is improved.

Optionally or preferably, in the gravity sensor, each component made of quartz material is welded and assembled by oxyhydrogen flame. The assembling and mounting process of the oxyhydrogen flame is more suitable for the quartz material with the impurity content lower than 2ppm, and can improve the sensitivity and the stability of the quartz material.

Alternatively or preferably, in the gravity sensor, the cross-sectional diameter of the twisted wire is 30 to 70 μm. The thin torsion wire has better rotation performance, the rotation is generated by the slight displacement change of the movable polar plate, the sensitivity is higher, and the overall measurement precision of the sensor can be further improved.

The electronic gravimeter provided by the invention comprises the gravity sensor, wherein the upper fixed polar plate, the lower fixed polar plate and the movable polar plate of the gravity sensor realize signal feedback and signal control through a conducting cable.

Compared with the prior art, the invention has the following beneficial effects:

the gravity sensor is made of quartz materials, the quartz frame consisting of the spring and other parts is connected to form a quartz elastic system for gravity signal acquisition, electric signal conduction is realized through the conducting film, signal feedback and signal control are carried out, the problems that the traditional mechanical gravity meter gravity sensor cannot output digital gravity signals and cannot form electric signal feedback are solved, the measurement precision is high, and the gravity sensor is more suitable for an electronic gravity meter.

The whole gravity sensor is only provided with one spring, so that the structure of the sensor is simplified.

The stopper, the upper fixed polar plate, the lower fixed polar plate, the twisted wire and other structures are matched to form a unique limiting form, so that the firmness and the stability of the gravity sensor are enhanced.

Drawings

FIG. 1 is a schematic perspective view of a gravity sensor according to an embodiment;

FIG. 2 is a side view of FIG. 1;

FIG. 3 is a top view of FIG. 1;

FIG. 4 is a schematic diagram of gravity sensor signal detection;

fig. 5 is a schematic diagram of a capacitance displacement sensing system of the gravity sensor.

In the figure:

1. bottom frame 2, swing frame 3, twisted wire

4. Spring 5, upper fixed polar plate 6 and lower fixed polar plate

7. Movable polar plate 8, polar plate support 9 and limiter support

10. Stopper 11, stopper 12, connecting rod.

Detailed Description

The present invention is explained and illustrated in detail below with reference to specific examples so that those skilled in the art can better understand and practice the present invention.

Referring to fig. 1-3, an embodiment of a gravity sensor includes a bottom frame, a swing frame, a torsion wire, a connecting rod, a spring, an upper fixed pole plate, a lower fixed pole plate, a pole plate support, a movable pole plate, a limiting block, a limiting stopper, and a limiting stopper support. The bottom frame, the swinging frame, the torsion wires, the connecting rods, the springs, the upper fixed polar plates, the lower fixed polar plates, the polar plate supports, the movable polar plates and the limiter supports are made of quartz materials. The limiting stopper is made of metal materials, and the limiting stopper is made of alloy materials.

The bottom frame is connected with the swing frame, the upper part of the swing frame is connected with the torsion wire, the torsion wire is connected with the movable polar plate through the connecting rod, the movable polar plate is connected with the limiting block, the limiting block moves in the adjusting range of the limiting block, and the limiting block is connected with the bottom frame through the limiting block support; the upper fixed polar plate and the lower fixed polar plate are arranged in parallel and are respectively connected with the bottom frame through polar plate supports, and the movable polar plate is positioned in a limiting space formed between two planes of the upper fixed polar plate and the lower fixed polar plate; one end of the spring is connected with the movable polar plate, and the other end of the spring is connected with the bottom frame. The surfaces of the torsion wire, the connecting rod, the upper fixed polar plate, the lower fixed polar plate and the movable polar plate are all provided with conductive films. When the movable polar plate moves up and down, one end of the movable polar plate drives the torsion wire to do small rotary deformation through the connecting rod, and the other end of the movable polar plate drives the limiting block to move in the limiting block. The elastic force of the spring and the deformation force of the torsion wire jointly make the pole plate return to the original state.

The above components are welded and assembled by oxyhydrogen flame, wherein an exemplary assembling process is as follows:

1. the manufactured bottom frame and the swinging frame are connected through a special tool, and then the pair of twisted wires are connected with the swinging frame through a special tool.

2. And (3) sintering the fixed polar plate support and the frame, and sintering and installing the lower fixed polar plate, the upper fixed polar plate and the fixed polar plate support by using a special tool according to design requirements.

3. The limiting block and the movable polar plate are integrally installed between the two fixed polar plates after being sintered and are simultaneously connected with the torsion wire.

4. The spring is installed and adjusted to a rest position.

5. And (4) installing the limiter at the designed position by using a special tool, and adjusting the limiting gap of the limiter.

6. And the conducting cable is utilized to lead out the electric signals of the fixed polar plate and the movable polar plate to realize signal feedback and signal control.

The special tool and special tool used in the assembling process do not influence the structure and the performance of the sensor, and are only used for more convenient assembling.

The gravity sensor has the working principle that:

the gravity sensor is the core component of electronic gravimeter (or called digital gravimeter), and it realizes the accurate measurement of the change of ground gravity (gravity difference) by the balance principle of gravity acting on the heavy load (movable polar plate), the elastic force of quartz spring and the feedback electrostatic force.

The core components of the gravity sensor are a quartz spring and a differential capacitance displacement sensor (mainly comprising a movable polar plate, an upper fixed polar plate and a lower fixed polar plate) with the capacity of pF level, and the signal detection principle of the gravity sensor is shown in FIG. 4.

In the system, the differential capacitance displacement sensor is actually used as a 'zero point' indicator, when the movable plate of the capacitance displacement sensor deviates from the initial position due to the change of the gravity value, the circuit outputs a corresponding voltage value, the voltage signal is fed back to the capacitance displacement sensor to pull (push) the movable plate back to the original position (zero point), the feedback voltage value is in direct proportion to the change of the gravity value, and the computer system records the feedback voltage value and multiplies the feedback voltage value by a scaling coefficient to obtain the gravity value.

The stray capacitance of the differential capacitive displacement sensor also has a large influence on the sensitivity and has high requirements on the process, and the assembly by welding is preferably performed by oxyhydrogen flame. To improve sensitivity, quartz materials with impurity levels below 2ppm are preferred for the components of the overall gravity sensor. Quartz materials of this purity are available directly as commercial products (e.g., lawski, germany).

According to calculation, when the weight is elongated by 20mm under the gravity of 1G, and the resolution of the gravimeter reaches 1 micro gamma, the displacement resolution of the capacitance displacement sensor should be:

20÷980×10⁶≈2×10^-8mm/micro-gamma is 0.02nm (nanometer)/micro-gamma

The resolution of 1 micro gamma is achieved, and the displacement resolution of the capacitance displacement sensor is 0.02 nm.

The differential capacitive displacement sensor used herein is commonly used for measuring minute displacement, and the sensing system principle is shown in fig. 5.

The output voltage of the capacitor end is:

here, theIs the excitation voltage,. DELTA.d is the displacement, d₀Is the plate distance.

Amplified and detected, and then sent to a computer circuit.

When the gravity sensor is applied to an electronic gravimeter, the electronic gravimeter mainly comprises subsystems such as the gravity sensor, a vacuum bin, a whole machine damping system, a constant temperature measuring device, an inclination measuring subsystem and a self-calibration subsystem. The upper fixed polar plate, the lower fixed polar plate and the movable polar plate of the gravity sensor realize signal feedback and signal control through the conducting cable.

The following table 1 shows the measurement data of the test using the electronic gravimeter:

TABLE 1

The measured data shows that the electronic gravimeter provided with the gravity sensor has an error of 8 micro gamma in measurement, and meets the requirement of high precision within a range of less than 10 micro gamma.

The inventive concept is explained in detail herein using specific examples, which are given only to aid in understanding the core concepts of the invention. It should be understood that any obvious modifications, equivalents and other improvements made by those skilled in the art without departing from the spirit of the present invention are included in the scope of the present invention.