JPH10206202A - Composite sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite sensor which is simple in structure and can be made compact easily. SOLUTION: A cantilever 20 deforming a diaphragm 30 when receiving a dynamic pressure from a fluid is coupled perpendicularly at a central part of the diaphragm 30 deformed when receiving a static pressure from the fluid. A plurality of strain gauges (GP1-GP4), GF1-GF4 for detecting a mechanical displacement of the diaphragm 30 are arranged in a cross on a surface of the diaphragm 30. It accordingly becomes possible to measure both the pressure (static pressure) of the fluid and a flow rate based on the detection of the dynamic pressure of the fluid. Moreover, only the diaphragm 30 and the cantilever 20 are primary mechanical components, so that a simple structure is achieved. The strain gauges (GP1-GP4), GF1-GF4 can be easily formed at the diaphragm 30 by plasma CVD, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite sensor for simultaneously measuring a flow rate and a pressure of a fluid such as a liquid or a gas flowing through a pipe or the like.

[0002]

2. Description of the Related Art Since the volume of a fluid such as a liquid or a gas fluctuates depending on pressure, temperature, etc., in flow measurement, pressure measurement and temperature measurement are performed simultaneously, and these pressure measurement values and temperature measurement values are measured. May have to correct the flow measurement to a predetermined volume. In particular, since the volume of a gas fluctuates significantly depending on pressure, temperature, and the like, it is important to correct the measured flow rate to the volume in a standard state. In performing the flow measurement with such correction, if the flow sensor, the pressure sensor, and the temperature sensor are separately provided, the mounting work of each sensor becomes complicated, and in some cases, the sensors are concentrated at a desired position. Cannot be measured, and the measured values differ even when the same equipment is used. In particular, the flow sensor and the pressure sensor
It is desirable to provide them at the same location, but it is difficult to provide the usual one at the same location.

[0003] Therefore, a device which solves the above-mentioned problem by integrating a flow sensor and a pressure sensor (Sho Tokusho)
No. 63-70121) is known. This device is provided with a T-shaped arm in which a vertical bar inserted into a tube through which a fluid flows is connected to the center of a horizontal bar arranged parallel to the tube outside the tube. ing.
Both ends of the horizontal bar of the T-shaped arm are connected to the cylindrical portion via columns. And these pillars have the first
And a second load sensor, respectively. In the vicinity of the base end of the vertical bar, there is provided a flange-shaped disk formed parallel to the flow direction of the fluid. Further, a pressure receiving surface facing the flow direction of the fluid is provided at the tip of the vertical bar. The tubular portion has an opening through which the vertical bar is inserted. One end of a bellows cylinder is connected to this opening. The other end of the bellows cylinder is closed by a disk of a vertical bar. According to such an apparatus, since the pressure (static pressure) of the fluid is received by the disk portion and both the first and second load sensors are deformed in the same direction, the sum of the measured values from these load sensors is obtained. , The pressure of the fluid can be measured. On the other hand, the dynamic pressure of the fluid received by the pressure receiving portion deforms the first and second load sensors in opposite directions, so that the dynamic pressure of the fluid can be detected from the difference between the measured values obtained by these load sensors. It has become. Then, based on the detected dynamic pressure, the flow velocity of the fluid, and thus the flow rate, can be measured.

[0004]

However, in the apparatus described above, mechanical components are used. Since the structure requires many parts, it takes a long time for the assembling work, and also takes a long time for the mounting work for attaching the load sensor to the support with an adhesive or the like, resulting in a problem that the manufacturing efficiency is not good. In addition, since the structure requires many components, there is a problem that the whole is likely to be large and downsizing is difficult.

An object of the present invention is to provide a composite sensor which has a simple structure and can be easily miniaturized.

[0006]

SUMMARY OF THE INVENTION The present invention is a composite sensor for simultaneously measuring the flow rate and pressure of a fluid to be measured, wherein the sensor is arranged parallel to the direction in which the fluid flows and has one surface. A diaphragm portion in contact with a fluid, a cantilever portion having a proximal end joined to the one surface of the diaphragm portion and a distal end extending in a direction intersecting the flow direction of the fluid, and an electric resistance corresponding to mechanical displacement of the diaphragm portion. And a plurality of strain gauges radially arranged on the surface of the diaphragm portion. According to the present invention, the pressure of the fluid is measured by receiving the pressure (static pressure) of the fluid at the diaphragm and detecting the displacement of the diaphragm with a strain gauge provided on the surface thereof. On the other hand, the fluid dynamic pressure is
The cantilever is received by the cantilever, and the cantilever causes a displacement in the diaphragm, and the displacement is detected by a strain gauge of the diaphragm. Thus, the dynamic pressure of the fluid is detected, and the flow rate is measured from the dynamic pressure. Therefore, only a diaphragm part and a cantilever part are required as main mechanical parts, and a simple structure that does not require many parts is obtained. Since the diaphragm is a flat plate having elasticity, when a plurality of strain gauges are radially provided on the surface thereof, a physical vapor gap (PVD) such as a vacuum evaporation method is used.
our Deposition and plasma CVD (Chemical Vapou)
r Deposition) can be easily used, and the strain gauge can be easily formed. In addition, since a plurality of strain gauges are arranged radially, the positions between the strain gauges are separated from each other, and when these strain gauges are formed, they do not interfere with each other even if they are miniaturized. Becomes easier.

In the above, the cantilever portion includes:
A fluid receiving surface that receives the flowing fluid is provided to face the flow direction of the fluid, and the surface of the diaphragm portion serves as the strain gauge to detect a displacement of the diaphragm portion caused by receiving the pressure of the fluid. A plurality of first strain gauges provided for detecting, and a plurality of first strain gauges provided for detecting displacement of the diaphragm portion caused by receiving the fluid on the fluid receiving surface of the cantilever portion. 2 strain gauges, the first strain gauge is arranged in a direction orthogonal to the flow direction of the fluid, and the second strain gauge is arranged along the flow direction of the fluid. It is desirable. With this configuration, the first strain gauge is also dedicated to detecting the pressure of the fluid, and the second strain gauge is dedicated to detecting the dynamic pressure, and the pressure signal and the dynamic pressure signal are separated from the sensor. And the electrical processing can be easily performed, and the configuration of an arithmetic circuit and the like connected downstream of the sensor becomes simple. In addition, if the first strain gauges are arranged in a direction perpendicular to the flow direction of the fluid, the first strain gauges can be arranged in a portion where displacement of the diaphragm caused by receiving the dynamic pressure on the cantilever portion is minimized. Become like Thereby, the sensitivity of the first strain gauge to the dynamic pressure is reduced, so that even if the flow rate measurement is performed with the same diaphragm, the effect is reduced. And
If the second strain gauges are arranged in a direction orthogonal to the flow direction of the fluid, the displacement of the diaphragm caused by the dynamic pressure applied to the cantilever is located at a position where the displacement in the opposite direction before and after the diaphragm is reversed. It becomes possible to arrange a strain gauge. This makes it possible to offset the component of the output of the second strain gauge due to the pressure of the fluid, so that even if the pressure is measured with the same diaphragm, the effect is reduced.

[0008] The diaphragm portion is provided with a thick portion having a thickness dimension larger than that of a peripheral portion at a central portion,
It is preferable that a base portion of the cantilever portion is joined to a surface of the thick portion where the fluid is in contact, and a temperature detection portion whose electric resistance changes according to temperature is provided on a surface opposite to the thick portion. . With this configuration, the connection strength of the cantilever portion to the diaphragm portion is sufficiently ensured, and the durability of the sensor is ensured.
Displacement does not occur in the temperature detection unit due to the pressure of the fluid, etc., and even if the temperature detection unit is provided in the diaphragm unit,
Accurate temperature measurement can be performed.

Further, the diaphragm portion is made of metal, and the surface of the diaphragm portion not in contact with the fluid is covered with an insulating layer of silicon dioxide, and the strain gauge is formed on the insulating layer. It is desirable to use a silicon thin film that has been formed. In this way, it is possible to easily use film forming methods such as PVD and CVD and photoengraving techniques, and it is possible to miniaturize the diaphragm with a strain gauge and to mass-produce the diaphragm. It becomes possible.

[0010] The plurality of strain gauges may receive a compressive force due to deformation of the diaphragm, and
It is preferable to be provided at both positions where tension is applied by deformation of the diaphragm. With this configuration, even if the first strain gauge detects the displacement of the diaphragm caused by the dynamic pressure applied to the cantilever, the electrical change due to the displacement can be canceled, and the same diaphragm can be used. The effect of performing the flow measurement in the section is minimized. On the other hand, even if the second strain gauge detects the displacement of the diaphragm caused by the pressure of the fluid, it is possible to cancel the electrical change due to the displacement, and the pressure is measured with the same diaphragm. The effect of this is minimal.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. 1 and 2 show a composite sensor 1 according to the present embodiment. In the composite sensor 1, a mechanism for simultaneously measuring a flow rate and a pressure is provided in a cylindrical body 10 connected to a pipe through which a fluid to be measured flows. A flow path 11 through which the above-described fluid passes is provided inside the cylindrical body 10, and connection portions 12 for connecting pipes are provided at both ends of the flow path 11. Connection 12
Is a female screw portion 13 on the inner peripheral surface side and a tool engaging portion 14 on the outer peripheral surface side.
And The female screw portion 13 gradually decreases in diameter toward the inside, and is screwed with a so-called tapered male screw. The tool engagement portion 14 is formed in a hexagonal nut shape, and is adapted to engage with a tool such as a spanner. An opening 16 that penetrates a side wall 15 of the cylindrical body 10 is provided in an intermediate portion of the cylindrical body 10. Around the opening 16, a rising portion 17 protruding from the outer peripheral surface of the cylindrical body 10 is provided.

The opening 16 is closed with a disk-shaped diaphragm 30 with a cantilever 20 traversing the flow path 11 inserted therein. The cantilever portion 20 is connected to the center portion of the diaphragm portion 30, and the diaphragm portion 30 is connected to the cylindrical body 10 via a ring-shaped member 31.
Is connected to the rising portion 17 of Here, the distal end side of the cantilever portion 20 is rotated by the deformation of the diaphragm portion 30. In addition, a concave portion 18 is provided on the inner peripheral surface of the flow channel 11 at a portion facing the opening 16. The concave portion 18 serves as a stopper into which the tip of the cantilever portion 20 is inserted to suppress the amount of rotation of the cantilever portion 20 from becoming excessive.

The cantilever portion 20 has a rod-like shape whose base end is joined to the diaphragm portion 30 and whose front end extends in a direction intersecting the flow direction of the fluid. A portion of the cantilever portion 20 that fits within the flow path 11 is provided with a fluid receiving surface 21 that faces the fluid in the flowing direction and that receives the fluid. When the cantilever portion 20 is a metal round bar, the fluid receiving surface 21 can be formed by crushing a predetermined portion of the round bar. Diaphragm part 30,
It is arranged parallel to the direction in which the fluid in the flow path 11 flows. As shown in FIGS. 3 and 4, the diaphragm portion 30 is provided with a central thick portion 32 and a peripheral thick portion 33 having large thickness dimensions at a central portion and a peripheral portion.
Between these thick portions 32, 33, a deformed thin portion 34 having a small thickness is provided. Of which, the central thick part 32
In the figure, the lower surface in the figure is a surface that comes into contact with the fluid, and the base of the cantilever portion 20 is joined to this surface by welding. The ring-shaped member 31 to be welded to the cylindrical body 10 is also joined to the peripheral thick portion 33 by welding. Here, the deformable thin portion 34 of the diaphragm portion 30 is displaced by both the pressure (static pressure) of the fluid and the rotation of the cantilever portion 30 in the flow path 11.

A plurality of strain gauges GF1 to GF4, GP1 to GP4, whose electric resistance changes according to the mechanical displacement of the diaphragm 30, are provided on the surface of the diaphragm 30 not in contact with the fluid.
And a temperature detector GT whose electric resistance changes according to the temperature. Among them, the temperature detecting part GT is provided in the central thick part 32 of the diaphragm part 30. Strain gauge
GP1 to GP4 and GF1 to GF4 are radially arranged on the deformed thin portion 34 of the diaphragm 30. Among them, the strain gauges GP1 to GP4 are first strain gauges provided to detect the displacement of the diaphragm 30 caused by receiving the pressure of the fluid. These strain gauges GP1 to GP4
Are arranged in a line in a direction perpendicular to the flow direction of the fluid, as shown in FIG. On the other hand, the strain gauges GF1
GF4 is a second strain gauge provided to detect a displacement of the diaphragm section 30 caused by the fluid receiving surface 21 of the cantilever section 20 receiving a fluid. These strain gauges GF1 to GF4 are arranged in a line along the flow direction of the fluid.

Here, as shown in FIG. 6, the strain gauges GP1 and GP3 are provided near the inner peripheral edge of the deformed thin portion 34 of the diaphragm 30. Meanwhile, strain gauge GP
2, GP4 is provided at a position near the outer peripheral edge of the deformable thin portion. As a result, when the diaphragm portion 30 is deformed upward in the drawing by receiving the pressure (static pressure) of the fluid, the deformed thin portion 34
The surface in the vicinity of the inner peripheral edge becomes an outer surface of the bend, so that tension is applied to the strain gauges GP1 and GP3. Further, when the diaphragm portion 30 is deformed as described above, the surface near the outer peripheral edge of the deformed thin portion 34 becomes the inner surface of the bend, so that a compressive force is applied to the strain gauges GP2 and GP4. Therefore, when the diaphragm 30 is deformed by the static pressure of the fluid, the strain gauges GP1, GP1
GP3, while the electrical resistance increases, strain gauge GP2
GP4 is arranged so that electric resistance may be small.

As shown in FIG. 7, the strain gauges GF1 and GF3 are provided near the inner peripheral edge of the deformed thin portion 34 of the diaphragm 30, and the strain gauges GF2 and GF4 are disposed at the outer peripheral edge of the deformed thin portion 34. Is provided in the vicinity of. As a result, the fluid receiving surface 21 of the cantilever portion 20 receives the dynamic pressure of the fluid, and the diaphragm portion 30 is deformed in response to the tip of the cantilever portion 20 turning leftward in the drawing, and the deformed thin portion 34
The surface near the inner peripheral edge on the left side in the drawing and the surface near the outer peripheral edge on the right side in the drawing become outer surfaces of the bend, so that tension is applied to the strain gauges GF1 and GF4.
Further, when the diaphragm portion 30 is deformed as described above, the surface of the deformed thin portion 34 near the outer peripheral edge on the left side in the drawing and the surface near the inner peripheral edge on the right side in the drawing becomes an inner surface of the bend. A compressive force is applied to the GF3. Therefore, the diaphragm part is driven by the dynamic pressure of the fluid.
When the strain 30 is deformed, the strain gauges GF1 and GF4 are arranged such that the electrical resistance increases, while the strain gauges GF2 and GF3 are arranged so that the electrical resistance decreases.

Further, when the diaphragm portion 30 is deformed in response to the rotation of the cantilever portion 20 in the direction perpendicular to the direction of fluid flow, the strain gauges GP1 to GP4 become strain gauges GF1 to GF4 shown in FIG. Is replaced by the strain gauges GP1 to GP4, the electrical resistance of the strain gauges GP1 and GP4 increases, while the electrical resistance of the strain gauges GP2 and GP3 decreases. When the diaphragm 30 is deformed by receiving the static pressure of the fluid, the strain gauges GF1 to GF4 are replaced by the strain gauges GF1 to GF3, as shown in FIG. While the electrical resistance increases, the electrical resistance of the strain gauges GF2 and GF4 decreases. The diaphragm section 30 is made of metal. The surface of the diaphragm portion 30 that is not in contact with the fluid is
Covered with an insulating layer of silicon dioxide. Strain gauge GP1
~ GP4, GF1 ~ GF4 are plasma CV
A silicon thin film formed by lamination according to the method D is formed into a predetermined planar shape by a photolithography technique.

FIG. 8 shows the electrical connection of the strain gauges GP1 to GP4. In the figure, one end of a strain gauge GP1 is connected to one end of a strain gauge GP2 at a connection point a, and the other end is connected to one end of a strain gauge GP4 at a connection point d. The other end of the strain gauge GP2 is a strain gauge
It is connected to one end of GP3 at connection point b. The other end of the strain gauge GP3 is connected to the other end of the strain gauge GP4 at a connection point c. Such a strain gauge GP1
To GP4, a pressure detector 2 for detecting the pressure (static pressure) of the fluid is formed. Input terminals 41 and 42 are connected to the connection points b and d of the pressure detecting unit 2, respectively, and a predetermined voltage is applied to these input terminals 41 and 42. Output terminals are provided at connection points c and a of the pressure detection unit 2.
The output terminals 43 and 44 are connected to output electrical signals corresponding to the pressure of the fluid.

FIG. 9 shows the electrical connection of the strain gauges GF1 to GF4. In the figure, strain gauge GF1
Has one end connected to one end of the strain gauge GF2 at a connection point e, and the other end connected to one end of the strain gauge GF3 at a connection point h. The other end of the strain gauge GF2 is connected to one end of the strain gauge GF4 at a connection point f. The other end of the strain gauge GF4 is connected to the other end of the strain gauge GF3 at a connection point g. The connection of the strain gauges GF1 to GF4 forms the flow rate detecting unit 3 that detects the flow rate from the static pressure of the fluid. Flow detector 3
Input terminals 45 and 46 are connected to the connection points f and h, respectively, and a predetermined voltage is applied to these input terminals 45 and 46. At the connection points g and e of the flow rate detector 3,
Output terminals 47 and 48 are connected respectively, and these output terminals
From 47 and 48, an electric signal corresponding to the flow rate of the fluid is output.

Next, the operation of the present invention will be described. Now, assuming that the diaphragm portion 30 is deformed upward in the drawing as shown in FIG. 6 under the pressure of the fluid, the strain gauges GP1, GP
3, a tensile force is applied to the strain gauges GP2 and GP4, and a compressive force is applied to the strain gauges GP2 and GP4, so that the electrical resistance of the strain gauges GP1 and GP3 increases according to the strength of the fluid pressure, and the strain gauges GP
2. The electrical resistance of GP4 is reduced. Where the strain gauge
GP1 to GP4 are set so that the absolute value of the change in electric resistance is equal, and if the absolute value is ΔR, the change in strain gauges GP1 and GP3 is + ΔR as shown in FIG. The change of the gauges GP2 and GP4 is -ΔR. For this reason, the potential of the connection point c rises, and the potential of the connection point a falls, whereby an electric signal corresponding to the pressure of the fluid is output between the output terminals 43 and 44. When the part 30 is deformed, the strain gauges GF1, GF
3, the electrical resistance of the strain gauges GF2, GF4 decreases. Here, the strain gauges GF1 to GF4
Is set so that the absolute value of the change in electrical resistance is equal, and if the absolute value is ΔR, as shown in FIG.
The change of the strain gauges GF1 and GF3 is + ΔR, and the change of the strain gauges GF2 and GF4 is −ΔR. For this reason, the potentials of the connection points g and e are both lowered, whereby
Even if the diaphragm 30 is deformed by the pressure of the fluid, the output terminal
No electric signal is generated between 47 and 48.

Next, as the fluid receiving surface 21 of the cantilever portion 20 receives the dynamic pressure of the fluid and the tip of the cantilever portion 20 rotates to the left in the drawing, the diaphragm portion 30 is moved as shown in FIG. If it is deformed, a tension is applied to the strain gauges GF1 and GF4, and a compressive force is applied to the strain gauges GF2 and GF3.
This allows strain gauges to be used in accordance with the dynamic pressure of the fluid.
The electrical resistance of GF1 and GF4 increases, and strain gauges GF2
The electrical resistance of GF3 decreases. Here, the strain gauge GF1
.About.GF4 are set so that the absolute value of the change in electric resistance is equal, and if the absolute value is .DELTA.r, the change in strain gauges GF1 and GF4 is + .DELTA.r as shown in FIG. The change of GF2 and GF3 is -Δr.
For this reason, the potential of the connection point g rises, and the potential of the connection point e falls, whereby an electric signal corresponding to the dynamic pressure of the fluid, that is, the flow rate, is output between the output terminals 47 and 48. On the other hand, when the diaphragm portion 30 is deformed as described above, the electric resistance of the strain gauges GP1 and GP4 increases,
The electrical resistance of GP2 and GP3 decreases. Here, the strain gauges GP1 to GP4 are set so that the absolute value of the change in electric resistance is equal, and if the absolute value is Δr,
As shown in FIG. 8, the change of the strain gauges GP1 and GP4 is + Δr
And the change of the strain gauges GP2 and GP3 is -Δr. For this reason, the potentials of the connection points a and c are both lowered, so that no electric signal is generated between the output terminals 43 and 44 even if the diaphragm 30 is deformed by the dynamic pressure of the fluid.

According to the above-described embodiment, the following effects can be obtained. That is, the diaphragm 30 receives the pressure of the fluid, and the displacement of the diaphragm 30 is measured by the strain gauge GP1.
GPGP4, the dynamic pressure of the fluid is received by the cantilever portion 20, the diaphragm portion 30 is displaced by the cantilever portion 20, and the displacement is detected by the strain gauges GF1 to GF4. Since the temperature of the fluid is measured by the temperature detecting unit GT provided in, the pressure, flow rate and temperature of the fluid can be measured simultaneously.

Further, since the diaphragm 30 and the cantilever 20 constitute the main structure of the composite sensor 1, other mechanical elements are unnecessary, the number of parts is reduced, and the structure of the composite sensor 1 is simplified. The manufacturing efficiency can be improved and the whole can be downsized.

Further, the diaphragm portion 30 is formed in a plate shape, and a plurality of strain gauges GP1 to GP4, GF1 to GF
Since the plasma CVD and the photo-etching technique are used to form the strain gauge 4, the strain gauges GP1 to GP4 and GF1 to GF4 can be easily formed even if the diaphragm 30 is extremely small. In addition, since the plurality of strain gauges GP1 to GP4 and GF1 to GF4 are radially arranged, the interval therebetween is enlarged, and the strain gauges GP1 to GP4 and GF1 to GF4 are arranged.
When molding the diaphragm, the strain gauges GP1 to GP4, GF1 to GF4
Do not interfere with each other, which also facilitates manufacture.

Further, the strain gauges GF1 to GF4 are arranged in the direction of flow of the fluid to be dedicated to detecting the dynamic pressure of the fluid, and the strain gauges GP1 to GP4 are arranged in a direction perpendicular to the direction of flow of the fluid. Since the dynamic pressure signal and the static pressure signal are separately output from the composite sensor 1 for the purpose of detecting the static pressure of the fluid, electrical processing of these signals is facilitated. The configuration of the arithmetic circuit and the like connected at the subsequent stage can be simplified.

Further, since the cantilever portion 20 is provided with the fluid receiving surface 21 which faces the fluid in the flow direction of the fluid, the cantilever portion 20 can be rotated by joining to the diaphragm portion 30. The rotation direction of the cantilever portion 20 is determined in one direction by the dynamic pressure, and the displacement of the diaphragm 30 is detected by the dynamic pressure of the fluid.
4 alone. In addition, the strain gauges GF1 to GF4 are arranged before and after the cantilever section 20. At the positions of the front and rear strain gauges GF1 to GF4, the diaphragm section
Since the displacement of 30 was made in the opposite direction, the output signal was
The component due to the pressure of the fluid can be canceled, and even if the flow rate measurement and the pressure measurement are performed based on the same displacement of the diaphragm unit 30, there is no mutual influence.

In particular, strain gauges GP1, GP3, GF1, GF3
Is provided near the inner peripheral edge of the deformed thin portion 34, and the strain gauge
GP2, GP4, GF2, GF4 are provided in the vicinity of the outer peripheral edge of the deformed thin portion 34, and for a predetermined deformation of the diaphragm portion 30,
Tension is applied to the strain gauges GP1, GP3, GF1, GF3, and the strain gauges GP2, GP4, GF2, GF
4 is designed to apply a compressive force and a strain gauge GP
1 to GP4 are connected so that the components due to the dynamic pressure of the fluid are offset, and the strain gauges GF1 to GF4 are connected so that the components due to the static pressure of the fluid are offset. Thus, mutual influences can be reliably prevented.

Further, a central thick portion 32 having a larger thickness dimension than the peripheral portion is provided at a central portion of the diaphragm portion 30, and a base portion of the cantilever portion 20 is joined to one surface of the central thick portion 32, Since the temperature detection part GT is provided on the other surface of the central thick part 32, the connection strength of the cantilever part 20 to the diaphragm part 30 is sufficiently ensured, and the durability of the composite sensor 1 can be improved. Since the temperature detector GT is not displaced by the fluid pressure or the like, even if the diaphragm unit 30 is provided with the temperature detector GT, the temperature detector GT is not affected by the fluid pressure or the like.
The temperature can be measured accurately.

Further, the diaphragm portion 30 is made of metal, the surface of the diaphragm portion 30 is covered with an insulating layer of silicon dioxide, and strain gauges GP1 to GP4, GF1 to GF4 made of a silicon thin film are formed on the insulating film. Since plasma CVD and photolithography techniques are used for forming the diaphragm, the diaphragm unit 30 with the strain gauge can be miniaturized and mass-produced.

Although the present invention has been described with reference to the preferred embodiment, the present invention is not limited to this embodiment, and various improvements and design changes may be made without departing from the spirit of the present invention. It is possible. For example, the joining portion between the diaphragm portion and the cantilever portion is not limited to one in which the joining portion is a flat surface and these flat surfaces are joined to each other, and as shown in FIG. 10, the proximal end of the cantilever portion 20A is connected. Is formed in a tapered shape, and a mortar-shaped concave portion corresponding to the base end of the cantilever portion 20A is provided in the central thick portion 32A of the diaphragm portion 30A, and the cantilever portion 20A is formed.
May be welded in a state where the base end is fitted into the concave portion of the central thick portion 32A. In this way, the thickness of the peripheral thick portion 33A of the diaphragm portion 30A is large, and even if the welding rod 4 which is horizontal from the side of the joint cannot be brought close to the welding portion, even if the welding rod 4 is oblique, Can be brought closer to the joint, for example, the cantilever portion 20A and the predetermined angle θ
Therefore, it is possible to bring the welding rod 4 closer to the joint portion, so that the welding can be facilitated. It is preferable that the angle θ be around 45 degrees.

The number and arrangement of the strain gauges are not limited to the numbers and arrangements described in the above embodiment. If there are two or more strain gauges, the arrangement is not limited. The number and the sequence of can be appropriately selected for implementation. However, according to the above-described embodiment, an effect is obtained that the mutual influence between the flow rate measurement and the pressure measurement can be reliably prevented. Further, the temperature detector
It may be omitted, and when it is installed, its installation position is
It is not limited to the diaphragm portion, but may be provided on the cylindrical body,
If it is provided in the diaphragm part, the manufacture becomes easy as in the above-described embodiment. Further, the diaphragm is not limited to the metal, but may be a ceramic, and the material of the diaphragm can be appropriately selected in practice.
Further, the insulating layer of the diaphragm portion is not limited to that made of silicon dioxide, but may be made of a synthetic resin. The insulating layer can be omitted if an electric insulator made of ceramic or the like is used as the material of the diaphragm. Further, the strain gauge is not limited to the one formed of a silicon thin film, but may be a metal film or the like. The material of the strain gauge can be appropriately selected upon implementation.

[0032]

As described above, according to the present invention, the structure can be simplified, the manufacturing efficiency can be improved, and miniaturization and mass production can be easily realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an entire embodiment of the present invention.

FIG. 2 is a side view of the embodiment shown in FIG.

FIG. 3 is an enlarged sectional view taken along line III-III in FIG.

FIG. 4 is an enlarged sectional view taken along line IV-IV in FIG. 1;

FIG. 5 is an enlarged plan view showing a diaphragm section of the embodiment.

FIG. 6 is an enlarged sectional view taken along line VI-VI in FIG. 5;

FIG. 7 is an enlarged sectional view taken along line VII-VII of FIG. 5;

FIG. 8 is a connection diagram of a first strain gauge in the present embodiment.

FIG. 9 is a connection diagram of a second strain gauge in the present embodiment.

FIG. 10 is a sectional view showing a modification of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Composite sensor 20 Cantilever part 21 Fluid receiving surface 30 Diaphragm part 32 Central thick part as thick part GP1-GP4 First strain gauge GF1-GF4 Second strain gauge GT Temperature detector

Claims (5)

[Claims] 1. A composite sensor for simultaneously measuring a flow rate and a pressure of a fluid to be measured, wherein the diaphragm is arranged in parallel with a direction in which the fluid flows and one surface of which is in contact with the fluid. A cantilever portion having a base end joined to the one surface of the diaphragm portion and a tip extending in a direction intersecting with the flow direction of the fluid; and an electrical resistance varying according to mechanical displacement of the diaphragm portion, and A composite sensor comprising: a plurality of strain gauges radially arranged on a surface. 2. The composite sensor according to claim 1, wherein the cantilever portion is provided with a fluid receiving surface for receiving the flowing fluid, facing the flowing direction of the fluid, and a surface of the diaphragm portion. A plurality of first strain gauges provided as the strain gauges for detecting displacement of the diaphragm portion caused by receiving the pressure of the fluid.
And a plurality of second strain gauges provided for detecting displacement of the diaphragm portion caused by the fluid receiving surface of the cantilever portion receiving the fluid, wherein the first strain gauges are provided. Wherein the strain gauges are arranged in a direction orthogonal to the flow direction of the fluid, and the second strain gauges are arranged along the flow direction of the fluid. 3. The composite sensor according to claim 1, wherein the diaphragm has a thick portion having a larger thickness at a central portion than a peripheral portion at a central portion. A composite sensor, wherein a base portion of the cantilever portion is joined to a surface in contact with a fluid, and a temperature detecting portion whose electric resistance changes according to temperature is provided on a surface opposite to the thick portion. 4. The composite sensor according to claim 1, wherein said diaphragm portion is made of metal, and a surface of said diaphragm portion which is not in contact with said fluid is made of an insulating material of silicon dioxide. A composite sensor covered with a layer, wherein the strain gauge is a silicon thin film formed on the insulating layer. 5. The composite sensor according to claim 1, wherein the plurality of strain gauges receive a compressive force due to the deformation of the diaphragm, and a tension due to the deformation of the diaphragm. A composite sensor provided at both of the receiving positions.