CN219016353U - Piezoelectric acceleration sensor with near constant pretightening force in full temperature zone - Google Patents

Abstract

The utility model discloses a piezoelectric acceleration sensor with near-constant pretightening force in a full-temperature region, which is characterized in that a bolt pad is added, so that high-temperature thermal mismatch caused by inconsistent thermal expansion coefficients of metal parts and piezoelectric materials in the piezoelectric acceleration sensor is relieved, and the sensor is ensured to be in a near-constant pretightening state in the full-working temperature region; the pre-tightening force of the bolt of the acceleration sensor is kept consistent with the initial pre-tightening force as much as possible along with the temperature rise, so that the influence of the force-thermal coupling field on the piezoelectric constant of the piezoelectric sensitive element is eliminated, the sensitivity temperature drift of the sensor is consistent with the temperature drift of the piezoelectric constant of the piezoelectric sensitive element, in addition, the near constant pre-tightening force of the full temperature area is kept, the linearity of the piezoelectric acceleration sensor is consistent with that at room temperature, and the linearity deterioration caused by the pre-tightening force change caused by the temperature rise is avoided. The piezoelectric acceleration sensor controls the pretightening force change through structural design to improve the high-temperature performance of the piezoelectric acceleration sensor, and the improvement method is simple and reliable.

Description

Piezoelectric acceleration sensor with near constant pretightening force in full temperature zone

Technical Field

The utility model relates to the field of sensors, in particular to a piezoelectric acceleration sensor with near constant pretightening force in a full temperature zone.

Background

The piezoelectric acceleration sensor is also called a piezoelectric accelerometer, and converts an external vibration signal into an electric signal through the piezoelectric effect of the piezoelectric sensitive element, so that the vibration measurement of the environment is realized. When the piezoelectric acceleration sensor is excited by external vibration, the force of the mass block acting on the piezoelectric sensitive element changes along with the external vibration, and then the output signal of the piezoelectric sensitive element also changes along with the change of the external vibration, and when the vibration frequency is far smaller than the resonance frequency of the piezoelectric acceleration sensor, the vibration frequency and the resonance frequency are in a proportional relation.

In the development of high-end equipment such as aerospace, heavy-duty gas turbines and nuclear power stations, higher requirements are put forward on the high-temperature tolerance of the piezoelectric acceleration sensor for vibration monitoring of the high-end equipment. With the increase of the use temperature, the adhesive for fixing the parts of the sensor usually fails, the parts of the piezoelectric acceleration sensor are usually fixed and pre-tightened by bolts and nuts, and then the pre-tightening force of the bolts can be attenuated along with the increase of the temperature, so that the temperature drift of the sensor due to the action sensitivity of a force-thermal coupling field is increased, and the performances such as linearity, impact resistance and the like are reduced. Therefore, it is necessary to design a piezoelectric acceleration sensor with near constant pre-tightening force in a full temperature area, so as to relieve the performance reduction of the sensor caused by the attenuation of the pre-tightening force due to the temperature rise and improve the service performance of the piezoelectric acceleration sensor in a high-temperature environment.

Disclosure of Invention

The utility model aims to overcome the defects in the prior art and provides a piezoelectric acceleration sensor with near constant pretightening force in a full temperature zone.

In order to achieve the above object, the technical scheme of the present utility model is as follows:

the utility model provides a nearly permanent pretightning force's of full temperature zone piezoelectric acceleration sensor, includes shell, base, mass block, piezoelectric sensing element, bolt, nut and bolt pad, be equipped with the center post on the base, the center post is equipped with two relative assembly basal planes, and two assembly basal planes are equipped with first through-hole, piezoelectric sensing element be equipped with the second through-hole that corresponds of first through-hole, the mass block be equipped with the third through-hole and the fourth through-hole that correspond of first through-hole, the fourth through-hole orientation piezoelectric sensing element one side, a plurality of piezoelectric sensing element with the mass block is installed in proper order symmetry two on the assembly basal plane, adjacent two between the piezoelectric sensing element and between the piezoelectric sensing element with the center post or be equipped with the electrode piece between the mass block, the bolt pad is installed the head of bolt and is installed in the third through-hole, the bolt passes first through-hole, second through-hole, third through-hole and fourth through-hole, and with the nut is connected to provide normal pretightening force fastening mass block, mass block and center pad and cushion, and the mass block are installed for the taper cone-shaped element, the boss is installed to the base, the taper cone-shaped stud is formed with the top between the base, the cone-shaped stud is installed to the cone.

Preferably, the taper of the conical round table of the bolt is the same as the taper of the conical through hole of the bolt pad.

Preferably, the thickness of the conical round table of the bolt is the same as the thickness of the bolt pad.

Preferably, a stepped structure is formed between a third through hole and a fourth through hole of the mass block, the depth of the third through hole is the same as that of the fourth through hole, the thickness of the third through hole is the same as that of the bolt pad, the diameter of the third through hole is larger than that of the fourth through hole, and the diameter of the fourth through hole is equal to that of the first through hole and the second through hole.

Preferably, the area of the surface of the mass facing the piezoelectric sensing element is larger than or equal to the area of the surface of the piezoelectric sensing element contacting the mass.

Preferably, the piezoelectric sensitive element comprises piezoelectric ceramics or piezoelectric crystals, and the surfaces of two sides of the piezoelectric sensitive element are provided with thin film layers.

Preferably, the piezoelectric sensitive elements are square, the number of the piezoelectric sensitive elements is 2-6, the piezoelectric sensitive elements are symmetrically distributed on two sides of the central column, and when the number of the used piezoelectric sensitive elements is more than 2, two adjacent piezoelectric sensitive elements on one side of the central column are connected in parallel in a mode of opposite polarities.

Preferably, the electrode sheet is a platinum metal sheet or a nickel metal sheet, and has the same contact area as the piezoelectric sensitive element.

Preferably, a stepped hole is formed in the bottom of the shell, and the base is clamped on the stepped hole and is connected in a laser welding mode.

Compared with the prior art, the utility model has the following beneficial effects:

(1) The piezoelectric acceleration sensor with near constant pretension in the full-working temperature region can realize the tiny change of the pretension of the piezoelectric acceleration sensor in the full-working temperature region from room temperature to high temperature, thereby improving the linearity, the shock resistance and other performances of the piezoelectric acceleration sensor at high temperature and reducing the sensitivity temperature drift of the piezoelectric acceleration sensor in the full-working temperature region.

(2) The piezoelectric acceleration sensor with the near constant pre-tightening function in the full working temperature area has a simple structure and tight fit, can relieve the performance reduction of the sensor caused by the attenuation of the pre-tightening force due to the temperature rise, and improves the service performance of the piezoelectric acceleration sensor in a high-temperature environment.

(3) The piezoelectric acceleration sensor with the near-constant pre-tightening full-working temperature area provided by the utility model has the advantages that the bolt pre-tightening force of the acceleration sensor is kept consistent with the initial pre-tightening force as much as possible along with the temperature rise through the design of the structures such as the bolt pad and the like, so that the influence of a force-thermal coupling field on the piezoelectric constant of the piezoelectric sensitive element is eliminated, the sensitivity temperature drift of the sensor is consistent with the temperature drift of the piezoelectric constant of the piezoelectric sensitive element, in addition, the near-constant pre-tightening force of the full-working temperature area is kept, the linearity of the piezoelectric acceleration sensor is kept consistent with the linearity at room temperature, the linearity deterioration caused by the pre-tightening force change caused by the temperature rise is avoided, and the high-temperature performance of the piezoelectric acceleration sensor is improved through controlling the pre-tightening force change, so that the improvement method is simple and reliable.

Drawings

The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and together with the description serve to explain the principles of the utility model. Many of the intended advantages of other embodiments and embodiments will be readily appreciated as they become better understood by reference to the following detailed description.

FIG. 1 is a schematic diagram of a piezoelectric acceleration sensor with near constant preload in the full temperature zone in accordance with an embodiment of the present application;

FIG. 2 is a schematic cross-sectional view of a piezoelectric acceleration sensor with near constant preload in the full temperature zone in accordance with an embodiment of the present application;

FIG. 3 is an assembled top view of an embodiment of the present application above the base of a full temperature zone near constant preload piezoelectric acceleration sensor;

FIG. 4 is a schematic diagram of a bolt of a piezoelectric acceleration sensor with near constant preload in the full temperature zone in accordance with an embodiment of the present application;

FIG. 5 is a schematic diagram of a bolt pad of a piezoelectric acceleration sensor with near constant preload in the full temperature zone in accordance with an embodiment of the present application;

reference numerals: 1. a housing; 2. a mass block; 3. a piezoelectric sensitive element; 4. an electrode sheet; 5. a bolt pad; 6. a nut; 7. a center column; 8. a base; 9. and (5) a bolt.

Detailed Description

The present application is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the utility model and are not limiting of the utility model. It should be noted that, for convenience of description, only the portions related to the present utility model are shown in the drawings.

It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

Referring to fig. 1-5, the embodiment of the utility model provides a piezoelectric acceleration sensor with a full temperature zone and near constant pretightening force, which comprises a shell 1, a base 8, a mass block 2, a piezoelectric sensitive element 3, a bolt 9, a nut 6 and a bolt pad 5, wherein a central column 7 is arranged on the base 8, two opposite assembly base surfaces are arranged on the central column 7, the base 8 and the central column 7 are specifically formed by integrally forming, the joint of the base 8 and the central column 7 is a round angle, and the assembly base surface of the central column 7 is rectangular. The two assembly base surfaces are provided with first through holes, the piezoelectric sensing element 3 is provided with second through holes corresponding to the first through holes, the mass block 2 is provided with third through holes and fourth through holes corresponding to the first through holes, the fourth through holes face one side of the piezoelectric sensing element 3, the third through holes are arranged on the other side, the first through holes, the second through holes, the third through holes and the fourth through holes have the same axle center, the diameter of the third through holes is larger than that of the fourth through holes, the diameter of the fourth through holes is equal to that of the first through holes and the second through holes, and the piezoelectric sensing element 3 and the mass block 2 are conveniently assembled on the assembly base surfaces on two sides of the center column 7. The piezoelectric sensing elements 3 and the mass blocks 2 are sequentially and symmetrically arranged on two assembly base surfaces, specifically, the piezoelectric sensing elements 3 are firstly arranged on the assembly base surfaces on two sides of the center column 7, the mass blocks 2 are arranged on the side surfaces of the piezoelectric sensing elements 3, electrode plates 4 are arranged between two adjacent piezoelectric sensing elements 3 and between the piezoelectric sensing elements 3 and the center column 7 or the mass blocks 2, the piezoelectric sensing elements 3 are enabled to be output in parallel, and the piezoelectric sensing elements 3, the mass blocks 2, the electrode plates 4 and the center column 7 are assembled together through bolts 9, bolt pads 5 and nuts 6. The bolt pad 5 is installed at the head of the bolt 9 and in the third through hole, the bolt 9 passes through the first through hole, the second through hole, the third through hole and the fourth through hole and is connected with the nut 6, so that the normal pretightening force is provided for fastening the mass block 2, the piezoelectric sensitive element 3, the central column 7 and the bolt pad 5, the head of the bolt 9 is a conical round table, the bolt pad 5 is provided with a conical through hole matched with the conical round table, namely, the conical degree of the conical round table of the bolt 9 is the same as that of the conical through hole of the bolt pad 5, the conical round table is clamped in the conical through hole, and in the temperature change process, the normal pretightening force between the bolt 9 and the mass block 2, the piezoelectric sensitive element 3 and the central column 7 is changed through the volume change of the bolt pad 5, the bolt 9, the mass block 2, the piezoelectric sensitive element 3 and the central column 7, so that the normal pretightening force is approximately kept consistent in the temperature change process, and the bolt 9 in the whole temperature range is realized by adopting the bolt pad 5 for thermal compensation. The base 8 is arranged on the shell 1, the center column 7, the mass block 2, the piezoelectric sensitive element 3, the bolt 9, the nut 6 and the bolt pad 5 are arranged in a cavity formed between the shell 1 and the base 8, specifically, a stepped hole is formed in the bottom of the shell 1, the base 8 is clamped on the stepped hole and connected in a laser welding mode, and the packaging of the piezoelectric acceleration sensor is realized. In the preferred embodiment, the housing 1 takes the form of a triangular mounting, increasing the reliability of the piezoelectric acceleration sensor.

In a specific embodiment, referring to fig. 4 and 5, the head of the bolt 9 is processed into a conical frustum with a certain taper, the center of the bolt pad 5 is also processed into a conical through hole with a certain taper, the taper of the two is the same, and the thickness of the conical frustum of the bolt 9 is the same as the thickness of the bolt pad 5. The conical frustum of the bolt 9 is fully embedded in the conical through-hole of the bolt pad 5, and the assembled conical frustum of the bolt 9 and the bolt pad 5 can be accommodated in the third through-hole.

In a specific embodiment, a stepped structure is formed between the third through hole and the fourth through hole of the mass block 2, the depth of the third through hole is the same as that of the fourth through hole, and the depth of the third through hole is the same as that of the bolt pad 5, one side of the bolt pad 5 is abutted to the bottom of the conical frustum of the bolt 9, and the other side of the bolt pad is abutted to the stepped structure. A gap is arranged between the side edge of the bolt pad 5 and the inner wall of the third through hole. The surface of the mass block 2 facing the piezoelectric sensitive element 3 is larger than or equal to the surface of the piezoelectric sensitive element 3 contacting the mass block 2, so that the piezoelectric sensitive element 3 can be completely attached to the mass block 2.

In a specific embodiment, the piezoelectric sensing element 3 comprises piezoelectric ceramics or piezoelectric crystals, and the two side surfaces of the piezoelectric sensing element 3 are provided with thin film layers. In the preferred embodiment, the film layer is a platinum film, and the piezoelectric sensing element 3 is coated with a platinum film with a certain thickness on two sides before use, and the piezoelectric sensor works by adopting a shear piezoelectric constant. Specifically, the piezoelectric acceleration sensor is of a shear type structure, the piezoelectric sensitive elements 3 are square, the number of the piezoelectric sensitive elements is 2-6, the piezoelectric sensitive elements are symmetrically distributed on two sides of the central column 7, and when the number of the piezoelectric sensitive elements 3 is greater than 2, two adjacent piezoelectric sensitive elements 3 on one side of the central column 7 are connected in parallel in a mode of opposite polarities.

In a specific embodiment, the electrode sheet 4 is a platinum metal sheet or a nickel metal sheet, and has the same contact area as the piezoelectric sensitive element 3. The electrode sheet 4 has the same size as the piezoelectric sensitive element 3, and is obtained by laser cutting and forming.

While the present utility model has been described with reference to the specific embodiments thereof, the scope of the present utility model is not limited thereto, and any changes or substitutions will be apparent to those skilled in the art within the scope of the present utility model, and are intended to be covered by the present utility model. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (9)

1. The utility model provides a nearly permanent pretightning force's of full temperature district piezoelectric acceleration sensor, its characterized in that includes shell, base, quality piece, piezoelectricity sensing element, bolt, nut and bolt pad, be equipped with the center post on the base, the center post is equipped with two relative assembly basal planes, and two assembly basal planes are equipped with first through-hole, piezoelectricity sensing element be equipped with the second through-hole that corresponds of first through-hole, the quality piece be equipped with the third through-hole that corresponds of first through-hole and fourth through-hole, fourth through-hole orientation piezoelectricity sensing element one side, a plurality of piezoelectricity sensing element with quality piece symmetry in proper order install two on the assembly basal plane, adjacent two between the piezoelectricity sensing element with be equipped with the electrode slice between center post or the quality piece, the bolt pad is installed the head of bolt is in the third through-hole, the bolt passes first through-hole, second through-hole, third through-hole and fourth through-hole to with the nut is connected to provide pretightening force fastening quality piece, quality piece and pad, and the quality piece are installed to the quality piece is installed to the symmetry in proper order on the base, the taper-shaped piece is located between the top of the base, the taper-shaped piece is formed with the taper top piece, the taper top is located with the top piece, the taper top piece is equipped with in the taper top piece.

2. The full temperature zone near constant preload piezoelectric acceleration sensor of claim 1, wherein the taper of the tapered frustoconical of the bolt is the same as the taper of the tapered through hole of the bolt pad.

3. The full temperature zone near constant preload piezoelectric acceleration sensor of claim 1, wherein the thickness of the conical frustum of the bolt is the same as the thickness of the bolt pad.

4. The piezoelectric acceleration sensor of claim 1, wherein a stepped structure is formed between a third through hole and a fourth through hole of the mass block, the depth of the third through hole is the same as the depth of the fourth through hole, the thickness of the third through hole is the same as the thickness of the bolt pad, the diameter of the third through hole is larger than the diameter of the fourth through hole, and the diameter of the fourth through hole is equal to the diameters of the first through hole and the second through hole.

5. The piezoelectric acceleration sensor of claim 1, characterized in that the surface of the mass facing the piezoelectric sensing element is larger than or equal to the surface of the piezoelectric sensing element in contact with the mass.

6. The piezoelectric acceleration sensor of claim 1, wherein the piezoelectric sensing element comprises piezoelectric ceramics or piezoelectric crystals, and the two side surfaces of the piezoelectric sensing element are provided with thin film layers.

7. The piezoelectric acceleration sensor with the full temperature zone near-constant pretightening force according to claim 1, wherein the piezoelectric sensitive elements are square, the number of the piezoelectric sensitive elements is 2-6, the piezoelectric sensitive elements are symmetrically distributed on two sides of the central column, and when the number of the used piezoelectric sensitive elements is more than 2, two adjacent piezoelectric sensitive elements on one side of the central column are connected in parallel in a mode of polarity opposition.

8. The piezoelectric acceleration sensor of claim 1, wherein the electrode plate is a platinum metal plate or a nickel metal plate and has the same contact area with the piezoelectric sensitive element.

9. The piezoelectric acceleration sensor with the full temperature zone near constant pretightening force according to claim 1, wherein a stepped hole is arranged at the bottom of the shell, and the base is clamped on the stepped hole and connected in a laser welding mode.

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