CN217605893U

CN217605893U - Compact triaxial piezoelectric accelerometer

Info

Publication number: CN217605893U
Application number: CN202221149016.5U
Authority: CN
Inventors: 王文龙; 笪良龙; 韩梅; 孙文祺; 姜兆祯
Original assignee: PLA Navy Submarine College
Current assignee: PLA Navy Submarine College
Priority date: 2022-05-13
Filing date: 2022-05-13
Publication date: 2022-10-18
Anticipated expiration: 2032-05-13

Abstract

A compact triaxial piezoelectric accelerometer relates to the technical field of piezoelectric accelerometers, and comprises a shell, 3 acceleration sensing units, 3 cover plates and 3 signal output lines; the casing is provided with 3 cylindrical cavities with openings on the outer surface of the casing along a X, Y, Z shaft, 1 acceleration sensing unit is arranged in each cylindrical cavity, a cover plate is arranged at the outer side end of each acceleration sensing unit, the edge of each cover plate is hermetically connected with the inner surface of each cylindrical cavity, one end of each signal output line is respectively penetrated into each cylindrical cavity and is electrically connected with the acceleration sensing unit in the cylindrical cavity, and the other end of each signal output line extends out of the casing. This novel compact structure, it is small, light in weight can use in the application occasion limited to volume, weight.

Description

Compact triaxial piezoelectric accelerometer

Technical Field

The utility model relates to a piezoelectric accelerometer technical field, concretely relates to compact triaxial piezoelectric accelerometer.

Background

According to the measurement principle, the types of accelerometers are classified into piezoelectric type, piezoresistive type, capacitive type, electromagnetic type, and the like. The piezoelectric accelerometer utilizes the positive piezoelectric effect of a piezoelectric material to measure the vibration acceleration. The piezoelectric accelerometers can be divided into plane compression type, bending beam type and shearing type according to different stress modes of the sensitive elements. The shear type piezoelectric accelerometer has the advantages of high sensitivity, low self-noise, moderate working frequency band, wide working temperature, good impact resistance and the like, and becomes the most widely used acceleration sensor at present.

At present, most of shear type three-axis piezoelectric accelerometers are provided with iron shells, and the shells not only play the role of a base, but also play the roles of shielding and protecting. In order to ensure sufficient protection and rigidity of the base, most of the iron shells are thick, so that the accelerometer has large volume and mass. For some applications where the installation space is small or the load carrying capacity is weak, the excessive volume and mass may limit the use of these piezoelectric accelerometers.

SUMMERY OF THE UTILITY MODEL

The utility model provides a compact triaxial piezoelectric accelerometer, the problem that exists among the prior art is solved to the purpose.

In order to achieve the purpose, the novel technical scheme is as follows:

a compact triaxial piezoelectric accelerometer comprises a shell, 3 acceleration sensitive units, 3 cover plates and 3 signal output lines; the casing is provided with 3 cylindrical cavities with openings on the outer surface of the casing along a X, Y, Z shaft, 1 acceleration sensing unit is arranged in each cylindrical cavity, a cover plate is arranged at the outer side end of each acceleration sensing unit, the edge of each cover plate is hermetically connected with the inner surface of each cylindrical cavity, one end of each signal output line is respectively penetrated into each cylindrical cavity and is electrically connected with the acceleration sensing unit in the cylindrical cavity, and the other end of each signal output line extends out of the casing.

Preferably, the housing is made of a cubic metal block, a fifth side surface of the housing is formed by cutting 1 plane between outer ports of 2 cylindrical cavities arranged along the X, Y shaft and adjacent to the side edges of the cubic metal block, the fifth side surface is provided with a signal output channel which extends inwards the housing and is communicated with each cylindrical cavity, and the signal output line is laid along the signal output channel.

Preferably, the bottom of the cylindrical cavity is provided with a mounting hole, an internal thread is arranged in the mounting hole, and the bottom end of the acceleration sensing unit is in threaded connection with the bottom of the cylindrical cavity.

Preferably, the acceleration sensing unit comprises a base, 2 weights, 2 shearing piezoelectric ceramic pieces, 2 electrode pieces, 1 screw, 1 insulating tube and 2 nuts;

the lower end of the base is provided with a stud which is in threaded connection with the mounting hole; the upper end of the base is provided with a cube-shaped supporting column along the axial direction, the 2 weight blocks are arranged on two sides of the cube-shaped supporting column, the opposite surfaces of the 2 weight blocks are symmetrically provided with grooves, and two ends of the cube-shaped supporting column extend into the corresponding grooves and are in clearance fit with the side walls of the corresponding grooves;

the bottom of the groove and the side surface of the corresponding cubic strut form an installation space, 1 shearing piezoelectric ceramic piece and 1 electrode piece are respectively arranged in 2 installation spaces, the shearing piezoelectric ceramic pieces and the electrode pieces in the same installation space are electrically connected, one surface of each shearing piezoelectric ceramic piece is abutted against the bottom of the groove, the other surface of each shearing piezoelectric ceramic piece is abutted against one surface of each electrode piece, and the other surface of each electrode piece is abutted against the outer surface of the corresponding cubic strut and is in insulation connection;

the weight, the shearing piezoelectric ceramic piece, the electrode plate and the cube-shaped strut are respectively coaxially provided with a connecting hole, an insulating pipe is arranged in the connecting hole, a screw rod penetrates through the insulating pipe, two ends of the screw rod extend into the connecting holes of the 2 weight, a nut is arranged in the connecting hole of the weight, the nut is in threaded connection with the screw rod, and the 2 weight, the shearing piezoelectric ceramic piece, the electrode plate and the cube-shaped strut which are arranged between the 2 weight are locked through the 2 nuts;

the bottom end of the weight is separated from the upper surface of the base, the electrode plate, the piezoelectric ceramic piece and the weight on one side form an electric series connection structure with the weight, the piezoelectric ceramic piece and the electrode plate on the opposite side through the screw and the nut, and one electrode plate is electrically connected with the end part of the signal output line.

Preferably, one surface of the electrode plate, which faces the piezoelectric ceramic plate, is provided with a conducting layer, and the other surface of the electrode plate is an insulating layer, wherein the conducting layer of one electrode plate is electrically connected with a signal output line, and the signal output line is a coaxial signal cable with a shielding layer.

Preferably, the base is of a circular structure, and the outer surface of the weight is an arc-shaped surface coaxial with the base.

Preferably, two exposed side surfaces of the cubic strut between the opposite surfaces of the 2 weight blocks are respectively provided with a tool groove, and the tool grooves are matched with a special tool screwdriver for use.

Preferably, the weight is made of tungsten metal material, and the X, Y, Z axes intersect.

This novel compact triaxial piezoelectric accelerometer's beneficial effect: 1. the novel structure is compact, the volume is small, the weight is light, and the novel structure can be applied to application occasions with limits on the volume and the weight; 2. the novel assembly between each acceleration sensitive unit and the shell adopts a threaded connection mode, so that the installation is simple and reliable, and the verticality is good; 3. the novel acceleration sensing unit adopts a piezoelectric shearing sensing structure, has no requirement on the initial angle and the termination angle of the threaded connection between the sensing unit and the shell, and is convenient to assemble; 4. the novel acceleration sensitive unit adopts a piezoelectric shear sensitive structure, so that the sensitivity is high, and the detection performance is better; 5. this novel casing is effectual with signal output line shielding, and anti-electromagnetic interference ability is strong.

Drawings

FIG. 1 is a perspective view schematically illustrating the structure of the present invention;

FIG. 2 is a cross-sectional view of the novel top view;

FIG. 3 is a schematic structural diagram of the acceleration sensing unit of the present invention;

1. a housing; 2. an acceleration sensitive unit; 3. a cover sheet; 4. a signal output line; 5. a cylindrical cavity; 6. mounting holes; 7. a signal output channel; 8. a base; 9. a weight block; 10. piezoelectric ceramic plates; 11. an electrode sheet; 12. a screw; 13. an insulating tube; 14. a nut; 15. a stud; 16. a cube-shaped pillar; 17. and (7) a tooling groove.

Detailed Description

The present invention is described in detail below with reference to the drawings, which are intended to illustrate preferred embodiments of the present invention and not to limit the scope of the present invention.

In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "top", "bottom", "inner", "outer", and the like indicate orientations and positional relationships based on the orientations and positional relationships shown in the drawings, and are only used for describing the present invention and simplifying the description, but do not indicate or imply that the device or the element to be referred to must have a specific orientation and a specific orientation configuration and operation, and thus, should not be construed as limiting the present invention.

A compact triaxial piezoelectric accelerometer is shown in FIGS. 1-3, and comprises a housing 1, 3 acceleration sensing units, 3

cover plates

3 and 3 signal output lines 4; 3 cylindrical cavities 5 with openings on the outer surface of the shell are arranged on the shell 1 along a X, Y, Z shaft, 1 acceleration sensing unit is arranged in each cylindrical cavity 5, a cover plate 3 is arranged at the outer side end of each acceleration sensing unit, the edge of each cover plate 3 is connected with the inner surface of each cylindrical cavity in a sealing mode, one end of each signal output line 4 penetrates through each cylindrical cavity 5 and is connected with the acceleration sensing unit in each cylindrical cavity 5 in an electric signal mode, and the other end of each signal output line extends out of the shell 1.

As shown in fig. 1 and 2, the housing 1 is made of a cubic metal block, a fifth side surface of the housing is formed by cutting 1 plane between outer ports of 2 cylindrical cavities 5 arranged along the axis X, Y and adjacent to the side edges of the cubic metal block, the fifth side surface is provided with a signal output channel 7 extending inwards the housing and communicated with each cylindrical cavity 5, and the signal output lines 4 are laid along the signal output channels 7.

As shown in fig. 1 and 2, a mounting hole 6 is formed in the bottom of the cylindrical cavity 5, internal threads are formed in the mounting hole 6, and the bottom end of the acceleration sensing unit is in threaded connection with the bottom of the cylindrical cavity 5.

As shown in fig. 1 and 3, the acceleration sensing unit includes a

base

8, 2

weights

9, 2 shearing piezoelectric

ceramic plates

10, 2 electrode plates 11, 1 screw 12, 1

insulating tube

13, and 2 nuts 14; namely, the acceleration sensitive units have the same structure; the lower end of the base is provided with a stud 15, and the stud 15 is in threaded connection with the mounting hole 6; the upper end of the base 8 is provided with a

cubic strut

16,2 weight blocks 9 along the axial direction, the two sides of the cubic strut 16 are provided with grooves (not marked in the figure) symmetrically arranged on the opposite surfaces of the 2 weight blocks 9, and the two ends of the cubic strut 16 extend into the corresponding grooves and are in clearance fit with the side walls of the corresponding grooves; an installation space is formed between the groove bottom and the side surface of the corresponding cubic strut, 1 shearing piezoelectric ceramic piece 10 and 1 electrode piece 11 are respectively arranged in 2 installation spaces, the shearing piezoelectric ceramic piece 10 and the electrode piece 11 in the same installation space are electrically connected, one surface of the shearing piezoelectric ceramic piece 10 is abutted against the groove bottom, the other surface of the shearing piezoelectric ceramic piece is abutted against one surface of the electrode piece 11, and the other surface of the electrode piece 11 is abutted against the outer surface of the cubic strut 16 and is in insulation connection; connecting holes are coaxially formed in the weight 9, the shearing piezoelectric ceramic piece 10, the electrode plate 11 and the cube-shaped strut 16 respectively, an insulating tube 13 is arranged in each connecting hole, a screw 12 penetrates through the insulating tube 13, two ends of the screw 12 extend into the connecting holes of the 2 weight pieces 9, a nut 14 is arranged in each connecting hole of each weight piece 9, the nut 14 is in threaded connection with the screw 12, and the 2 weight pieces, the shearing piezoelectric ceramic pieces 10, the electrode plate 11 and the cube-shaped strut 16 which are arranged among the 2 weight pieces are locked through the 2 nuts; the connecting holes of the weight can be stepped holes as required, so that the locking requirement is met, meanwhile, the insulating tube only extends into the small-diameter section of the stepped hole, the inner diameters of other connecting holes are the same except the connecting holes of the weight, other connecting holes are in interference fit with the insulating tube, and the small-diameter section can be in clearance fit with the insulating tube; as a preferred scheme, the screw rod is vertically arranged with the side wall of the cubic support column; the bottom end of the weight 9 is separated from the upper surface of the base 8, the electrode plate 11, the piezoelectric ceramic piece 10 and the weight 9 on one side form an electric series structure with the weight 9, the piezoelectric ceramic piece 10 and the electrode plate 11 on the opposite side through the screw 12 and the nut 14, and one electrode plate 11 is electrically connected with the end part of the signal output line 4.

As shown in fig. 1 and 3, one surface of the electrode plate 11 facing the piezoelectric ceramic plate 10 is provided with a conductive layer, and the other surface is an insulating layer, wherein the conductive layer of one electrode plate 11 is electrically connected to the signal output line 4, and the signal output line 4 is a coaxial signal cable with a shielding layer.

As shown in fig. 3, the base 8 is a circular structure, and the outer surface of the weight 9 is an arc-shaped surface coaxial with the base.

As shown in fig. 3, two exposed sides of the cubic strut 16 between the opposite sides of the 2 weights 9 are respectively provided with a tooling groove 17, and the tooling grooves 17 are matched with a special tooling screwdriver for use and are used for screwing the studs 15 on the base 8 on the corresponding mounting holes 6 at the bottom of the cylindrical cavity 5.

As shown in fig. 1, the weight 9 is made of tungsten metal material, and the X, Y, Z axes intersect.

This neotype theory of operation:

the three acceleration sensitive units are perpendicular to each other, respectively measure the vibration acceleration in the respective installation direction, and output the vibration acceleration signals of the three axes through the coaxial signal cables.

The weight of each acceleration sensing unit is provided with prestress clinging to the piezoelectric ceramic piece by the screw rod and the nut, after the acceleration sensing unit is acted by the vibration acceleration in the installation direction, the weight on the acceleration sensing unit can generate a vibration trend corresponding to the vibration acceleration due to inertia, and under the action of the prestress vertical to a contact surface, static friction force opposite to the vibration trend can be generated on the contact surface of the weight and the piezoelectric ceramic piece, the static friction force acts on the piezoelectric ceramic piece and is shearing force, voltage difference is generated between two electrodes of the piezoelectric ceramic piece under the action of the shearing force, and voltages on the two piezoelectric ceramic pieces of the same acceleration sensing unit are output in a series connection mode to form an output signal corresponding to the vibration acceleration. Three acceleration sensitive units which are orthogonal with each other measure the vibration acceleration in the respective installation direction, so that acceleration signals in three dimensions can be measured simultaneously.

Claims

1. A compact three-axis piezoelectric accelerometer characterized by: the device comprises a shell, 3 acceleration sensitive units, 3 cover plates and 3 signal output lines; the casing is provided with 3 cylindrical cavities with openings on the outer surface of the casing along a X, Y, Z shaft, 1 acceleration sensing unit is arranged in each cylindrical cavity, a cover plate is arranged at the outer side end of each acceleration sensing unit, the edge of each cover plate is hermetically connected with the inner surface of each cylindrical cavity, one end of each signal output line is respectively penetrated into each cylindrical cavity and is electrically connected with the acceleration sensing unit in the cylindrical cavity, and the other end of each signal output line extends out of the casing.

2. A compact three-axis piezoelectric accelerometer, as claimed in claim 1, wherein: the shell is made of a cubic metal block, a fifth side surface of the shell is formed by cutting 1 plane between outer ports of 2 cylindrical cavities arranged along a X, Y shaft and adjacent to the side edges of the cubic metal block, a signal output channel which extends inwards the shell and is communicated with each cylindrical cavity is arranged on the fifth side surface, and the signal output lines are laid along the signal output channel.

3. A compact three-axis piezoelectric accelerometer, as claimed in claim 2, wherein: the bottom of the cylindrical cavity is provided with a mounting hole, an internal thread is arranged in the mounting hole, and the bottom end of the acceleration sensing unit is in threaded connection with the bottom of the cylindrical cavity.

4. A compact three-axis piezoelectric accelerometer, as claimed in claim 3, wherein: the acceleration sensitive unit comprises a base, 2 weight blocks, 2 shearing piezoelectric ceramic pieces, 2 electrode plates, 1 screw, 1 insulating tube and 2 nuts;

5. A compact three-axis piezoelectric accelerometer, as claimed in claim 4, wherein: one surface of the electrode plate, facing the piezoelectric ceramic plate, is provided with a conducting layer, the other surface of the electrode plate is an insulating layer, the conducting layer of one electrode plate is electrically connected with a signal output line, and the signal output line is a coaxial signal cable with a shielding layer.

6. A compact three-axis piezoelectric accelerometer, as claimed in claim 4, wherein: the base is of a circular structure, and the outer surface of the heavy block is an arc-shaped surface coaxial with the base.

7. A compact three-axis piezoelectric accelerometer, as claimed in claim 4, wherein: two exposed side surfaces of the cubic strut between the opposite surfaces of the 2 heavy blocks are respectively provided with a tool groove, and the tool grooves are matched with a special tool screwdriver for use.

8. A compact three-axis piezoelectric accelerometer, as claimed in claim 4, wherein: the weight is made of tungsten metal material, and the X, Y, Z axes are intersected.