CN210155164U - Thermal expansion flow three-axis accelerometer - Google Patents
Thermal expansion flow three-axis accelerometer Download PDFInfo
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- CN210155164U CN210155164U CN201921102015.3U CN201921102015U CN210155164U CN 210155164 U CN210155164 U CN 210155164U CN 201921102015 U CN201921102015 U CN 201921102015U CN 210155164 U CN210155164 U CN 210155164U
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Abstract
The utility model discloses a thermal energy flows triaxial accelerometer, include: a top cover and a base; a flange extending outwards is arranged on the bottom surface of the top cover, a cylindrical upper cavity is arranged in the flange, four insulators arranged in a square shape are arranged in the upper cavity, and two thermosensitive wires for sensing the acceleration in the Z-axis direction are arranged on the four insulators; the top surface of the base is provided with a groove matched with the flange, a cylindrical lower cavity is arranged in the groove, four pairs of insulators which are opposite to each other in pairs and are parallel to each other are arranged in the lower cavity, and each pair of insulators is provided with a thermosensitive wire; and a heat source silicon chip is arranged at the center of the thermosensitive wire for sensing the acceleration in the X-axis direction and the acceleration in the Y-axis direction, and the heat source silicon chip is fixedly arranged in the lower chamber through an insulator. The utility model discloses can realize the measurement of triaxial acceleration. The fluid accelerometer has the advantages of simple structure, long service life, strong shock resistance and low cost, and can resist the interference of the external environment and improve the sensitivity of the fluid accelerometer.
Description
Technical Field
The utility model belongs to the technical field of the inertia measurement technique and specifically relates to a thermal energy flows triaxial accelerometer.
Background
In the past decades, the micro-mechanical accelerometer taking the cantilever supporting beam and the solid mass block as sensitive elements is easy to break or damage under the high-speed impact of the outside, and the structure is easy to fatigue; moreover, in order to increase the sensitivity of such accelerometers, it is necessary to place the sensitive elements in a vacuum environment and reduce the gas damping coefficient; such a manufacturing process is costly and complicated. In comparison, the fluid is used as a sensitive element, and the manufactured device has the characteristics of simple structure, strong shock resistance, long service life and low cost and has excellent performance. In the past, the accelerometer manufactured by utilizing the thermal convection principle has low sensitivity and is easily influenced by the external environment due to the fact that the flow velocity of thermal convection gas is low and the accelerometer depends on the gravity acceleration g. Due to the influence of the two factors, the sensitivity of the thermal convection accelerometer cannot be improved, and the application of the thermal convection accelerometer is limited. Therefore, those skilled in the art are devoted to developing a method capable of overcoming the influence of the above two factors on the accelerometer and improving the performance of the accelerometer.
The basic principle of an accelerometer using a thermally expanding fluid is: in the closed cavity, the suspended heat source applies periodic square wave voltage to generate heat, the surrounding gas medium is heated and expanded to form a moving thermal expansion flow, and the motion process of the thermal expansion flow conforms to the conservation of mass, momentum and energy. When acceleration along the direction of the X, Y, Z axis is input from the outside, due to the action of inertia force, the moving thermal expansion fluid causes the change of the temperature field in the cavity, the resistance value between a pair of metal resistance thermal sensitive wires along the input acceleration direction changes according to the thermal resistance effect, and the measurement of the input acceleration value can be realized through the corresponding detection circuit and the signal processing circuit.
The information disclosed in this background section is only for enhancement of understanding of the general background of the application and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a thermal energy flows triaxial accelerometer and its processing method to solve the technical problem who exists among the prior art.
In order to achieve the above purpose, the utility model adopts the following technical scheme:
the utility model provides a thermal energy flows triaxial accelerometer, a serial communication port, include: a top cover and a base; wherein the content of the first and second substances,
a flange extending outwards is arranged on the bottom surface of the top cover, a cylindrical upper cavity is arranged in the flange, four insulators arranged in a square shape are arranged in the upper cavity, two thermosensitive wires for sensing acceleration in the Z-axis direction are arranged on the four insulators, and the two thermosensitive wires are arranged in parallel;
the top surface of the base is provided with a groove matched with the flange, a cylindrical lower cavity is arranged in the groove, four pairs of insulators which are opposite and parallel in pairs are arranged in the lower cavity, each pair of insulators is provided with a thermosensitive wire, and the two pairs of parallel thermosensitive wires are respectively used for sensing the acceleration in the X-axis direction and the acceleration in the Y-axis direction;
a heat source silicon wafer is arranged at the center of the thermosensitive wire for sensing the acceleration in the X-axis direction and the acceleration in the Y-axis direction, and the heat source silicon wafer is fixedly arranged in the lower cavity through an insulator;
the top cover is in butt joint with the base and then sealed through sealant, after the top cover and the base are in butt joint, the upper chamber and the lower chamber form a sensitive chamber, and the thermosensitive wires sensitive to the acceleration in the Z-axis direction and the thermosensitive wires sensitive to the acceleration in the X-axis direction and the Y-axis direction are on the same plane.
As a further technical scheme, the thermosensitive wire sensitive to the acceleration in the Z-axis direction is of a reciprocating bent grid-shaped structure and is processed through an MEMS (micro electro mechanical systems) process.
As a further technical scheme, the thermosensitive wires sensitive to the acceleration in the X-axis direction and the acceleration in the Y-axis direction are made of Pt metal wires with the same length.
As a further technical scheme, thermosensitive wires sensitive to acceleration in the X-axis direction and acceleration in the Y-axis direction are vertically distributed on the periphery of a heat source silicon chip, and the distance between the thermosensitive wires and a heat source is equal.
As a further technical scheme, a thermosensitive wire sensitive to acceleration in the X-axis direction and a thermosensitive wire sensitive to acceleration in the Y-axis direction are connected to a binding post of the insulator through welding, and the thermosensitive wire sensitive to acceleration in the Z-axis direction and the heat source silicon wafer are connected to the binding post of the insulator through conductive glue.
A method of fabricating a thermal expansive flow triaxial accelerometer, said method comprising the steps of:
the method comprises the following steps: respectively processing a heat source silicon wafer and a thermosensitive wire sensitive to Z-axis acceleration by using an MEMS (micro electro mechanical system) process;
step two: drilling holes with the diameter the same as the size of the insulator at the corresponding positions of the top cover and the base, and installing the insulator in the corresponding holes;
step three: welding thermal sensitive wires sensitive to acceleration in the X-axis direction and acceleration in the Y-axis direction on the insulator binding post through a welding process; the thermosensitive wire and the heat source silicon wafer which are sensitive to Z-axis acceleration are respectively bonded on the insulator binding post by conductive adhesive;
step four: and butting the manufactured top cover and the base to form the thermal expansion flow triaxial accelerometer.
Adopt above-mentioned technical scheme, the utility model discloses following beneficial effect has:
the utility model discloses can realize the measurement of triaxial acceleration, and its simple structure, longe-lived, shock resistance are strong, with low costs, can resist external environment's interference and the sensitivity that improves fluid accelerometer simultaneously.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the technical solutions in the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic perspective view of a top cover according to an embodiment of the present invention;
fig. 2 is a schematic perspective view of a base according to an embodiment of the present invention;
fig. 3 is a top view of a top cover according to an embodiment of the present invention;
fig. 4 is a top view of a base according to an embodiment of the present invention;
fig. 5 is a schematic view of a connection structure between a thermosensitive wire sensitive to Z-axis acceleration and an insulator according to an embodiment of the present invention.
Icon: 1-a top cover; 2-a base; 3-a flange; 4-an upper chamber; 5, an insulator; 6-a thermosensitive wire; 7-a groove; 8-a lower chamber; 9-an insulator; 10-a thermo-sensitive filament; 11-heat source silicon chip.
Detailed Description
The technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the described embodiments are some, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.
The following detailed description of the embodiments of the present invention will be made with reference to the accompanying drawings. It is to be understood that the description of the embodiments herein is for purposes of illustration and explanation only and is not intended to limit the invention.
The embodiment provides a thermal expansion flow triaxial accelerometer and a processing method thereof.
As shown in conjunction with fig. 1 to 4, the accelerometer includes: a top cover 1 and a base 2; wherein the content of the first and second substances,
a flange 3 extending outwards is arranged on the bottom surface of the top cover 1, a cylindrical upper cavity 4 is arranged in the flange 3, four insulators 5 arranged in a square shape are arranged in the upper cavity 4, two thermosensitive wires 6 for sensing the acceleration in the Z-axis direction are arranged on the four insulators 5, and the two thermosensitive wires are arranged in parallel;
a groove 7 matched with the flange is formed in the top surface of the base 2, a cylindrical lower cavity 8 is formed in the groove 7, four pairs of insulators 9 which are opposite to each other in pairs and are parallel to each other are arranged in the lower cavity 8, a thermosensitive wire 10 is arranged on each pair of insulators 9, and the two pairs of parallel thermosensitive wires are used for sensing the acceleration in the X-axis direction and the acceleration in the Y-axis direction respectively;
a heat source silicon chip 11 is arranged at the center of the thermosensitive wire for sensing the acceleration in the X-axis direction and the acceleration in the Y-axis direction, and the heat source silicon chip 11 is fixedly arranged in the lower chamber 8 through an insulator;
the top cover 1 and the base 2 are in butt joint and then sealed through a sealant, after the top cover and the base are in butt joint, the upper chamber 4 and the lower chamber 8 form a sealed sensitive chamber, and the thermosensitive wires sensitive to the acceleration in the Z-axis direction and the thermosensitive wires sensitive to the acceleration in the X-axis direction and the Y-axis direction are on the same plane.
The thermal expansion flow triaxial accelerometer of the application has the following working principle:
when no external acceleration acts, the gas expands due to heating and flows in the positive direction of the Z axis, the temperature field of the gas is symmetrically distributed in the sensitive cavity, the resistance changes of the thermosensitive wires caused by the temperature field in the closed cavity are the same according to the thermal resistance effect, the Wheatstone bridge circuits connected with the two thermosensitive wires 6 for sensing the acceleration in the Z axis direction are still kept balanced, and the corresponding output voltage is zero.
When the acceleration which is the same as the positive direction of the Z axis is input from the outside, the speed of upward movement of the thermal expansion flow is reduced due to the action of inertia force, and at the moment, the time for the airflow in the sensitive cavity to reach the thermosensitive wire for detecting the acceleration of the Z axis is longer than the time for the airflow in the sensitive cavity to reach the thermosensitive wire for detecting the acceleration of the Z axis when no acceleration is input, so that a Wheatstone bridge circuit connected with the thermosensitive wire is not balanced in the process, and the corresponding output voltage is not zero any more. This enables the measurement of the acceleration in the same positive direction as the Z-axis.
When the acceleration which is the same as the Z-axis negative direction is input from the outside, the speed of the upward movement of the thermal expansion flow is increased due to the action of the inertia force, and at the moment, the time for the airflow in the sensitive cavity to reach the thermosensitive wire for detecting the Z-axis acceleration is less than the time for the airflow to reach the thermosensitive wire for detecting the Z-axis acceleration when no acceleration is input, so that a Wheatstone bridge circuit connected with the thermosensitive wire is not balanced in the process, and the corresponding output voltage is not zero any more. This enables measurement of acceleration in the same negative direction as the Z axis.
In fig. 2, four thermal sensitive wires 10 are respectively located at the upper, lower, left and right positions of a heat source silicon wafer 11. When a periodic square wave signal is applied to the hot wire of the heat source silicon chip 11, the air around the hot wire can expand by heat, and a periodic heat expansion flow is formed. The acceleration in the X-axis direction is input from the outside, temperature fields on the left side and the right side of the heat source silicon wafer are not symmetrically distributed due to the action of inertia force, the resistance values of two thermosensitive wires in the X-axis direction are detected to be different due to the thermal resistance effect, a Wheatstone bridge circuit connected with the thermosensitive wires sensitive to the acceleration in the X-axis direction is not balanced, and the corresponding output voltage is not zero, so that the measurement of the acceleration in the X-axis direction is realized. The acceleration in the Y-axis direction is input from the outside, temperature fields on the upper side and the lower side of the heat source silicon wafer are not symmetrically distributed due to the action of inertia force, the resistance values of two thermosensitive wires in the Y-axis direction are detected to be different due to the thermal resistance effect, a Wheatstone bridge circuit connected with the thermosensitive wire sensitive to the acceleration in the Y-axis direction is not balanced, and the corresponding output voltage is not zero any more, so that the measurement of the acceleration in the Y-axis direction is realized.
When the heat source works, under the heating of the square wave signal, gas around the heat source is heated and expanded to form periodic heat expansion flow.
When no external acceleration acts, the gas expands when heated and flows upwards, the temperature field of the gas is symmetrically distributed in the sensitive cavity, the change of the resistance of the thermosensitive wire caused by the temperature field is the same according to the thermal resistance effect, the Wheatstone bridge circuit connected with the thermosensitive wire keeps balance, and the corresponding output voltage is zero.
In this embodiment, as a further technical solution, the thermosensitive wire sensitive to the Z-axis acceleration is a reciprocating bending grid structure, and is processed by an MEMS process. The thermosensitive wires sensitive to the acceleration in the Z-axis direction are arranged into the grid-shaped structure which is bent in a reciprocating mode, so that the contact area of heat flow and the thermosensitive wires can be increased, and the sensitivity is improved.
In this embodiment, as a further technical solution, the thermosensitive wires sensitive to the acceleration in the X-axis direction and the thermosensitive wires sensitive to the acceleration in the Y-axis direction are made of Pt metal wires of the same length.
In the embodiment, as a further technical scheme, the thermosensitive wires sensitive to the acceleration in the X-axis direction and the acceleration in the Y-axis direction are vertically distributed on the periphery of the heat source silicon wafer, and the distances between the thermosensitive wires and the heat source are equal.
In the embodiment, as a further technical scheme, the thermosensitive wires sensitive to acceleration in the X-axis direction and the acceleration in the Y-axis direction are connected to the binding post of the insulator by welding, and the thermosensitive wire sensitive to acceleration in the Z-axis direction and the heat source silicon chip are bonded to the binding post of the insulator by conductive adhesive.
The present embodiments also provide a method of fabricating a thermal expansive flow triaxial accelerometer, the method comprising the steps of:
the method comprises the following steps: respectively processing a heat source silicon wafer and a thermosensitive wire sensitive to Z-axis acceleration by using an MEMS (micro electro mechanical system) process;
step two: drilling holes with the diameter the same as the size of the insulator at the corresponding positions of the top cover and the base, and installing the insulator in the corresponding holes;
step three: welding thermal sensitive wires sensitive to acceleration in the X-axis direction and acceleration in the Y-axis direction on the insulator binding post through a welding process; the thermosensitive wire and the heat source silicon wafer which are sensitive to Z-axis acceleration are respectively bonded on the insulator binding post by conductive adhesive;
step four: and butting the manufactured top cover and the base to form the thermal expansion flow triaxial accelerometer.
To sum up, by adopting the above technical scheme, the embodiment has the following beneficial effects:
the utility model provides a thermal energy flow triaxial accelerometer adopts two structures of top cap and base, and the temperature sensing silk of the sensitive Z axle acceleration of top cap installation installs the heat source on the base and the temperature sensing silk of sensitive X, Y axle accelerations, and the temperature sensing silk links to each other with the wheatstone bridge that corresponds to detect output signal. In addition, the accelerometer has the characteristics of simple structure, convenience in manufacturing and assembling, low cost, low power consumption, strong impact resistance and long service life.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.
Claims (5)
1. A thermal expansion flow three-axis accelerometer, comprising: a top cover and a base; wherein the content of the first and second substances,
a flange extending outwards is arranged on the bottom surface of the top cover, a cylindrical upper cavity is arranged in the flange, four insulators arranged in a square shape are arranged in the upper cavity, two thermosensitive wires for sensing acceleration in the Z-axis direction are arranged on the four insulators, and the two thermosensitive wires are arranged in parallel;
the top surface of the base is provided with a groove matched with the flange, a cylindrical lower cavity is arranged in the groove, four pairs of insulators which are opposite and parallel in pairs are arranged in the lower cavity, each pair of insulators is provided with a thermosensitive wire, and the two pairs of parallel thermosensitive wires are respectively used for sensing the acceleration in the X-axis direction and the acceleration in the Y-axis direction;
a heat source silicon wafer is arranged at the center of the thermosensitive wire for sensing the acceleration in the X-axis direction and the acceleration in the Y-axis direction, and the heat source silicon wafer is fixedly arranged in the lower cavity through an insulator;
the top cover is in butt joint with the base and then sealed through sealant, after the top cover and the base are in butt joint, the upper chamber and the lower chamber form a sensitive chamber, and the thermosensitive wires sensitive to the acceleration in the Z-axis direction and the thermosensitive wires sensitive to the acceleration in the X-axis direction and the Y-axis direction are on the same plane.
2. The thermal expansive flow triaxial accelerometer of claim 1, wherein said thermal sensitive wire sensitive to acceleration in the Z-axis direction is of a reciprocating bent grid-shaped structure and is fabricated by a MEMS process.
3. The thermal expansive flow triaxial accelerometer of claim 1, wherein the thermal sensitive wires sensitive to X-axis directional acceleration and sensitive to Y-axis directional acceleration are made of Pt wires of the same length.
4. The thermal expansive flow triaxial accelerometer of claim 1, wherein the thermal sensitive wires sensitive to the acceleration in the X-axis direction and the acceleration in the Y-axis direction are vertically distributed on the periphery of the heat source silicon wafer, and are equidistant from the heat source.
5. The thermal expansive flow triaxial accelerometer according to claim 1, wherein the thermal sensitive wires sensitive to the acceleration in the X-axis direction and the acceleration in the Y-axis direction are connected to the insulator terminal by welding, and the thermal sensitive wires sensitive to the acceleration in the Z-axis direction and the heat source silicon chip are connected to the insulator terminal by a conductive adhesive.
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| CN201921102015.3U CN210155164U (en) | 2019-07-15 | 2019-07-15 | Thermal expansion flow three-axis accelerometer |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110244081A (en) * | 2019-07-15 | 2019-09-17 | 北京信息科技大学 | A kind of expansion stream triaxial accelerometer and its processing method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110244081A (en) * | 2019-07-15 | 2019-09-17 | 北京信息科技大学 | A kind of expansion stream triaxial accelerometer and its processing method |
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