WO2023199838A1

WO2023199838A1 - Flow switch and flow switch attachment method

Info

Publication number: WO2023199838A1
Application number: PCT/JP2023/014223
Authority: WO
Inventors: 芽衣渡邊
Original assignee: 株式会社村田製作所
Priority date: 2022-04-14
Filing date: 2023-04-06
Publication date: 2023-10-19

Abstract

This flow switch is for detecting the flow of a fluid flowing inside a tube which is flexible and has a bending portion, and the flow switch comprises a sensor for detecting deformation of the tube. The sensor is fixed to the outer circumferential surface of the tube in the bending portion. As viewed along a first direction in which the fluid flows, the outer circumferential surface has: a first area positioned in a second direction from the center of the tube; and a second area positioned in a third direction from the center of the tube. The second direction and the third direction orthogonally intersect with the first direction. The third direction is a direction opposite to the second direction. The bending portion has a bending shape projecting in the second direction, and the sensor is fixed to the first area.

Description

Flow switch and flow switch installation method

The present invention relates to a flow switch that detects fluid flow and a flow switch mounting method.

As an invention related to a conventional flow switch and flow switch mounting method, for example, a water flow switch described in Patent Document 1 is known. This water flow switch includes a flow rate switch and a differential pressure operated opening/closing section. The flow switch detects small flow rates in the flow path. Further, the differential pressure operation opening/closing section opens the flow path based on the flow rate detected by the flow rate switch. Such a water flow switch is provided in a flow path through which water flows.

Japanese Patent Application Publication No. 2007-285992

By the way, in the water flow switch described in Patent Document 1, there is a desire to detect the flow of fluid without contacting the fluid to be detected.

Therefore, an object of the present invention is to provide a flow switch and a flow switch mounting method that can detect the flow of fluid without contacting the fluid to be detected.

A flow switch according to one embodiment of the present invention includes:
A flow switch that detects the flow of fluid flowing in a tube that is flexible and has a curved part,
The flow switch is
comprising a sensor section that detects deformation of the tube,
The sensor section is fixed to the outer peripheral surface of the tube and to the curved section.

A flow switch mounting method according to one embodiment of the present invention includes:
A flow switch mounting method for mounting a sensor section on a tube that is flexible and has a curved section, the method comprising:
The sensor section is fixed to the outer peripheral surface of the tube and to the curved section so that the sensor section detects deformation of the tube.

In this specification, direction is defined as follows. The direction in which the fluid flows is defined as a first direction DIR1. Further, a direction perpendicular to the first direction DIR1 is defined as a second direction DIR2. Further, a third direction DIR3 is defined as a direction opposite to the second direction DIR2. The second direction DIR2 and the third direction DIR3 are orthogonal to the first direction DIR1. Further, in the flow switch 1, the direction in which the first upper main surface US1 and the first lower main surface LS1 of the piezoelectric film 11 are lined up in a state in which the piezoelectric film 11 is expanded into a plane is defined as the up-down direction. Furthermore, when viewed in the vertical direction, the direction in which the long sides of the piezoelectric film 11 extend is defined as the left-right direction. The direction in which the short side of the piezoelectric film 11 extends when viewed in the vertical direction is defined as the front-back direction. The up-down direction, the left-right direction, and the front-back direction are orthogonal to each other. Note that the definition of direction in this specification is an example. Therefore, the direction when the flow switch 1 is actually used does not need to be the same as the direction in this specification. Further, the vertical direction may be reversed in FIGS. 1 to 15. The left and right directions in FIGS. 1 to 15 may be reversed. The front and rear directions may be reversed in FIGS. 1 to 15.

In the following, X and Y are parts or members of the flow switch 1. In this specification, unless otherwise specified, each part of X is defined as follows. The upper part of X means the upper half of X. The upper end of X means the upper end of X. The upper end of X means the upper end of X and its vicinity. This definition also applies to directions other than the upward direction.

Furthermore, "X is located above Y" means that X is located directly above Y. Therefore, when viewed in the vertical direction, X overlaps Y. "X is located above Y" means that X is located directly above Y, and that X is located diagonally above Y. Therefore, when viewed in the vertical direction, X may or may not overlap Y. This definition also applies to directions other than the upward direction.

In this specification, "X and Y are electrically connected" means that electricity is conducted between X and Y. Therefore, X and Y may be in contact with each other, or X and Y may not be in contact with each other. When X and Y are not in contact with each other, a conductive Z is placed between X and Y.

According to the present invention, it is possible to provide a flow switch and a flow switch mounting method that can detect the flow of fluid without contacting the fluid to be detected.

FIG. 1 is a perspective view of a flow switch 1 according to the first embodiment. FIG. 2 is a plan view of the sensor section 3 according to the first embodiment viewed from below. FIG. 3 is a cross-sectional view taken along line AA of the sensor section 3 according to the first embodiment. FIG. 4 is a side view of the tube 2 to which the sensor section 3 according to the first embodiment is fixed, viewed from the front. FIG. 5 is a sectional view taken along line BB of the tube 2, sensor section 3, and adhesive 4 according to the first embodiment. FIG. 6 is a side view of the tube 2 and the sensor section 3 viewed from the front in a state where the sensor section 3 according to the first embodiment is not fixed to the tube 2. FIG. 7 is a front side view of the tube 2 to which the sensor section 3 according to the first embodiment is fixed, in a state where water 5 is not flowing inside the tube 2. FIG. 8 is a front side view of the tube 2 to which the sensor section 3 according to the first embodiment is fixed, with water 5 flowing inside the tube 2. FIG. 9 is a side view of the tube 2 to which the sensor section 3 according to the first modification is fixed, viewed from the front. FIG. 10 is a sectional view taken along line BB of the tube 2, sensor section 3, and adhesive 4 according to the first modification. FIG. 11 is a side view of the tube 2 and the sensor section 3 viewed from the front in a state where the sensor section 3 according to the first modification is not fixed to the tube 2. FIG. 12 is a front side view of the tube 2 to which the sensor section 3 according to the first modification is fixed, in a state where water 5 is not flowing inside the tube 2. FIG. 13 is a front side view of the tube 2 to which the sensor section 3 according to the first modification is fixed, with water 5 flowing inside the tube 2. FIG. 14 is a sectional view taken along line BB of the tube 2, sensor section 3, and adhesive 4 according to the second modification. FIG. 15 is a sectional view taken along line BB of the tube 2, sensor section 3, and adhesive 4 according to the third modification.

[First embodiment]
Below, the configuration of a flow switch 1 according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a flow switch 1 according to the first embodiment. FIG. 2 is a plan view of the sensor section 3 according to the first embodiment viewed from below. FIG. 3 is a cross-sectional view taken along line AA of the sensor section 3 according to the first embodiment. FIG. 4 is a side view of the tube 2 to which the sensor section 3 according to the first embodiment is fixed, viewed from the front. FIG. 5 is a sectional view taken along line BB of the tube 2, sensor section 3, and adhesive 4 according to the first embodiment.

The flow switch 1 detects the flow of fluid flowing inside the flexible tube 2. The material of the tube 2 is, for example, metal or resin. Therefore, the tube 2 is elastically deformed.

The flow switch 1 includes a sensor section 3, as shown in FIG. The sensor section 3 detects deformation of the tube 2. In this embodiment, the deformation of the tube 2 detected by the sensor unit 3 is bending of the tube 2. Further, the sensor section 3 has flexibility. The sensor section 3 has a first upper main surface US1 and a first lower main surface LS1 that are arranged in the vertical direction. The normal direction of the first upper major surface US1 and the first lower major surface LS1 is the vertical direction. The first upper main surface US1 is located above the first lower main surface LS1.

As shown in FIG. 1, the sensor section 3 has a rectangular shape when viewed in the vertical direction. The sensor section 3 has a longitudinal direction extending in the left-right direction. Further, the sensor section 3 has a transversal direction extending in the front-rear direction. That is, the length of the sensor section 3 in the left-right direction is longer than the length of the sensor section 3 in the front-back direction.

The sensor section 3 includes a piezoelectric film 11, an upper electrode 12a, and an electrode member 13, as shown in FIG. The piezoelectric film 11 has a sheet shape. Therefore, as shown in FIG. 3, the piezoelectric film 11 has a second upper main surface US2 and a second lower main surface LS2 that are arranged in the vertical direction. The normal direction of the second upper major surface US2 and the second lower major surface LS2 is the vertical direction. The second upper main surface US2 is located above the second lower main surface LS2. Further, as shown in FIG. 2, the second upper main surface US2 and the second lower main surface LS2 of the piezoelectric film 11 have a longitudinal direction extending in the left-right direction when the piezoelectric film 11 is developed into a plane. There is. Moreover, the second upper main surface US2 and the second lower main surface LS2 of the piezoelectric film 11 have a transversal direction extending in the front-rear direction when the piezoelectric film 11 is developed into a plane. That is, the length of the piezoelectric film 11 in the left-right direction is longer than the length of the piezoelectric film 11 in the front-back direction.

In this embodiment, the piezoelectric film 11 has a rectangular shape when viewed in the vertical direction, as shown in FIG. That is, the second upper main surface US2 and the second lower main surface LS2 of the piezoelectric film 11 are arranged in the vertical direction (the second upper main surface US2 and the second lower main surface It has a rectangular shape when viewed in the normal direction of the main surface LS2. In addition, the second upper main surface US2 and the second lower main surface LS2 of the piezoelectric film 11 have a long side extending in the left-right direction and a short side extending in the front-rear direction when the piezoelectric film 11 is developed into a plane. are doing. The piezoelectric film 11 generates an electric charge according to the amount of deformation of the piezoelectric film 11. In this embodiment, the piezoelectric film 11 is a PLA film. Below, the piezoelectric film 11 will be explained in more detail.

The piezoelectric film 11 has a characteristic that the polarity of the charge generated when the piezoelectric film 11 is stretched in the left-right direction is opposite to the polarity of the charge generated when the piezoelectric film 11 is stretched in the front-back direction. There is. Specifically, the piezoelectric film 11 is a film formed from a chiral polymer. The chiral polymer is, for example, polylactic acid (PLA), particularly L-type polylactic acid (PLLA). PLLA, which is a chiral polymer, has a main chain having a helical structure. PLLA has piezoelectricity in which molecules are oriented by being uniaxially stretched. The piezoelectric film 11 has a piezoelectric constant of d14. As shown in FIG. 2, the uniaxial stretching direction OD of the piezoelectric film 11 forms an angle of 45 degrees with respect to each of the left-right direction and the front-back direction in a state where the piezoelectric film 11 is developed flatly. This 45 degrees includes, for example, an angle including approximately 45 degrees ±10 degrees. Thereby, the piezoelectric film 11 generates an electric charge when the piezoelectric film 11 is stretched in the left-right direction or in the front-back direction. The polarity of the charge generated by the piezoelectric film 11 when the piezoelectric film 11 is stretched in the left-right direction is different from the polarity of the charge generated by the piezoelectric film 11 when the piezoelectric film 11 is stretched in the front-back direction. For example, when the piezoelectric film 11 is stretched in the left-right direction, it generates negative charges. For example, when the piezoelectric film 11 is stretched in the front-back direction, it generates a positive charge. The magnitude of the charge depends on the amount of deformation of the piezoelectric film 11 due to expansion or compression. More precisely, the magnitude of the charge is proportional to the differential value of the amount of deformation of the piezoelectric film 11 due to expansion or compression.

The upper electrode 12a is a ground electrode. The upper electrode 12a has an upper main surface and a lower main surface that are arranged in the vertical direction. The upper electrode 12a is connected to ground. The upper electrode 12a is provided on the second upper main surface US2 of the piezoelectric film 11, as shown in FIG. The upper electrode 12a covers the entire second upper main surface US2 of the piezoelectric film 11. The upper electrode 12a includes an adhesive layer (not shown). The upper electrode 12a is fixed to the second upper main surface US2 of the piezoelectric film 11 by this adhesive layer. The upper main surface of the upper electrode 12a is the first upper main surface US1 of the sensor section 3.

The electrode member 13 is provided on the second lower main surface LS2 of the piezoelectric film 11, as shown in FIG. Further, the electrode member 13 includes a lower electrode 12b and a flexible printed circuit board 14.

The lower electrode 12b is a signal electrode. A detection signal is output from the lower electrode 12b. In this embodiment, the lower electrode 12b is provided on the upper main surface of the flexible printed circuit board 14, which will be described later, as shown in FIG. That is, the lower electrode 12b is a conductor layer provided on the upper main surface of the uppermost insulator layer among a plurality of insulator layers of the flexible printed circuit board 14, which will be described later.

The flexible printed circuit board 14 is a flexible circuit board. The flexible printed circuit board 14 has an upper main surface and a lower main surface that are arranged in the vertical direction. The flexible printed circuit board 14 includes a signal line, a ground line, and a plurality of insulating layers. The plurality of insulator layers are stacked in the vertical direction. The signal line and the ground line are conductor layers provided on the insulator layer. The signal line is electrically connected to the lower electrode 12b. A detection signal output from the lower electrode 12b is transmitted to the signal line. The ground line is electrically connected to the upper electrode 12a. The ground line is connected to ground potential. The lower main surface of the flexible printed circuit board 14 is the first lower main surface LS1 of the sensor section 3.

As shown in FIG. 4, such a sensor section 3 is fixed to the outer circumferential surface OS of the tube 2 via an adhesive 4. More specifically, the adhesive 4 covers the entire first lower main surface LS1 of the sensor section 3. Further, the adhesive 4 is fixed to the outer peripheral surface OS of the tube 2. In this embodiment, the sensor unit 3 is fixed to the outer peripheral surface OS of the tube 2 such that the long sides of the second upper main surface US2 and the second lower main surface LS2 of the piezoelectric film 11 extend in the first direction DIR1. . The short sides of the second upper main surface US2 and the second lower main surface LS2 of the piezoelectric film 11 extend around the tube 2 when viewed in the left-right direction.

In this embodiment, the tube 2 has a left straight part 21L, a right straight part 21R, and a curved part 22, as shown in FIG. The left straight portion 21L has a shape extending from the lower left direction to the upper right direction, and is not curved. The right straight portion 21R has a shape extending from the upper left direction to the lower right direction, and is not curved. The curved portion 22 has a shape extending in the left-right direction and includes a shape curved so as to protrude upward. The sensor section 3 is fixed to the curved section 22.

More specifically, in this embodiment, water 5 flows within the tube 2, as shown in FIG. Water 5 is an example of the fluid of the present invention. In this embodiment, the water 5 flows within the tube 2 from the left end of the left straight section 21L to the right end of the right straight section 21R. That is, in the left straight portion 21L, the first direction DIR1 is the upper right direction. Further, in the right straight portion 21R, the first direction DIR1 is the lower right direction. Further, in the curved section 22 , the water 5 flows inside the tube 2 from the left end of the curved section 22 to the right end of the curved section 22 . That is, in this embodiment, the first direction DIR1 is the upper right direction in the left portion of the curved portion 22. Further, in the right portion of the curved portion 22, the first direction DIR1 is the lower right direction. Further, at the center position of the curved portion 22 in the left-right direction, the first direction DIR1 is the right direction.

As shown in FIG. 4, the curved portion 22 includes a shape that is curved so as to protrude in the second direction DIR2. Specifically, the second direction DIR2 is an upward direction. The third direction DIR3 is the downward direction.

Further, the outer edge of the cross section perpendicular to the first direction DIR1 of the tube 2 includes a circular shape, as shown in FIG. Moreover, the inner edge of the cross section perpendicular to the first direction DIR1 of the tube 2 includes a circular shape. The outer peripheral surface OS includes a first region A1 located in a second direction DIR2 from the center O of the tube 2 and a second region A2 located in a third direction DIR3 from the center O of the tube 2 when viewed in the first direction DIR1. have. In this embodiment, the sensor section 3 is fixed to the first area A1.

By the way, the flow switch 1 has a structure that can detect the flow of fluid without coming into contact with the fluid to be detected. This structure will be explained below. FIG. 6 is a side view of the tube 2 and the sensor section 3 viewed from the front in a state where the sensor section 3 according to the first embodiment is not fixed to the tube 2. FIG. 7 is a front side view of the tube 2 to which the sensor section 3 according to the first embodiment is fixed, in a state where water 5 is not flowing inside the tube 2. FIG. 8 is a front side view of the tube 2 to which the sensor section 3 according to the first embodiment is fixed, with water 5 flowing inside the tube 2. In addition, in FIG. 8, in order to explain how the tube 2 and the sensor part 3 deform, the deformation of the tube 2 and the sensor part 3 is emphasized.

When the sensor section 3 is not fixed to the tube 2, the longitudinal direction of the second upper main surface US2 and the second lower main surface LS2 of the piezoelectric film 11 extends in the left-right direction. Further, in a state where the sensor section 3 is not fixed to the tube 2, the lateral direction of the second upper main surface US2 and the second lower main surface LS2 of the piezoelectric film 11 extends in the front-rear direction. Furthermore, the piezoelectric film 11 is slightly extended in the left-right direction with the sensor section 3 not being fixed to the tube 2. By moving the sensor section 3 downward from above the curved section 22 toward the curved section 22, as shown in FIG. , and fixed to the curved portion 22. In this embodiment, the sensor section 3 is fixed to the first region A1 and the curved section 22. The sensor section 3 is fixed to the tube 2 and is slightly extended in the left-right direction. As a result, while the sensor section 3 is fixed to the tube 2, tension is generated in the sensor section 3 to cause it to contract in the first direction DIR1 and in the opposite direction to the first direction DIR1. Thereby, the sensor section 3 can detect the deformation of the tube 2.

The magnitude of the charge generated by the piezoelectric film 11 is proportional to the differential value of the amount of deformation of the piezoelectric film 11 due to expansion or compression. That is, when the sensor section 3 is fixed to the tube 2 and the water 5 is not flowing inside the tube 2, the piezoelectric film 11 does not generate an electric charge. A detection signal indicating that the tube 2 is not deformed is transmitted to the signal line.

When the water 5 is flowing in the tube 2, the flow velocity of the water 5 located in the second direction DIR2 from the center O of the tube 2 is higher than the flow velocity of the water 5 located in the third direction DIR3 from the center O of the tube 2. big. Therefore, when the water 5 begins to flow inside the tube 2, the curved portion 22 deforms due to elastic deformation. More specifically, when the water 5 begins to flow within the tube 2, the curved portion 22 receives a force F from the water 5, as shown in FIG. Specifically, in the left straight portion 21L, the water 5 travels in the upper right direction. The curved portion 22 includes a shape that curves so as to protrude in the second direction DIR2. Therefore, the water 5 collides with a portion of the inner peripheral surface of the curved portion 22 located in the second direction DIR2 from the center O of the tube 2. As a result, the traveling direction of the water 5 changes, and the water 5 flows along the curved portion 22. At this time, the water 5 applies a force F to the curved portion 22. The direction of the force F is the second direction DIR2 because the curved portion 22 includes a curved shape so as to protrude upward. As a result, the curved portion 22 deforms due to elastic deformation. More specifically, the curved portion 22 deforms by elastic deformation so that the diameter of the curved portion 22 becomes larger. Thereby, the sensor section 3 is deformed so as to expand in the first direction DIR1. Therefore, the piezoelectric film 11 is stretched in the left-right direction. As a result, the piezoelectric film 11 generates negative charges. A detection signal indicating that the tube 2 has been deformed is transmitted to the signal line.

When the water 5 that was flowing inside the tube 2 begins to stop, the force F that the curved portion 22 was receiving from the water 5 becomes smaller. When the water 5 flowing through the tube 2 completely stops, the force F that the curved portion 22 was receiving from the water 5 becomes zero. As a result, the curved portion 22 deforms due to elastic deformation. More specifically, the curved portion 22 returns to the shape in which water 5 is not flowing through the tube 2 due to elastic deformation. Specifically, the curved portion 22 deforms by elastic deformation so that the diameter of the curved portion 22 becomes smaller. Thereby, the sensor section 3 is deformed so as to contract in the first direction DIR1. Therefore, the piezoelectric film 11 is compressed in the left-right direction. As a result, the piezoelectric film 11 generates positive charges. A detection signal indicating that the tube 2 has been deformed is transmitted to the signal line.

[effect]
According to the flow switch 1, the flow of fluid can be detected without contacting the fluid to be detected. More specifically, the tube 2 is flexible and has a curved portion 22. Thereby, when the fluid starts flowing inside the tube 2, the curved portion 22 receives a force F from the fluid. As a result, when fluid begins to flow within the tube 2, the curved portion 22 deforms. Further, when the fluid flowing inside the tube 2 completely stops, the force F that the curved portion 22 was receiving from the fluid becomes zero. As a result, when fluid begins to flow within the tube 2, the curved portion 22 deforms. Therefore, the flow switch 1 includes a sensor section 3 that detects the deformation of the tube 2. The sensor section 3 is fixed to the outer circumferential surface OS of the tube 2 and to the curved section 22 . Thereby, the flow switch 1 does not come into contact with the fluid to be detected. Further, in the flow switch 1, the sensor section 3 detects the deformation of the curved section 22, thereby detecting the flow of fluid. As a result, the flow switch 1 can detect the flow of fluid without coming into contact with the fluid to be detected.

According to the flow switch 1, the sensitivity for detecting fluid flow can be improved. More specifically, the curved portion 22 of the tube 2 includes a shape that curves so as to protrude in the second direction DIR2. Further, the outer circumferential surface OS of the tube 2 includes a first area A1 located in a second direction DIR2 from the center O of the tube 2, and a third direction from the center O of the tube 2, as viewed from the first direction DIR1 in which the fluid flows. It has a second area A2 located at DIR3. As a result, when the fluid starts flowing inside the tube 2, tensile stress acts on the first region A1 and the curved portion 22. On the other hand, when the fluid starts flowing inside the tube 2, compressive stress acts on the second region A2 and the curved portion 22. Therefore, the sensor section 3 is fixed to the first area A1. As a result, the charge generated in the piezoelectric film 11 when the piezoelectric film 11 is deformed by tensile stress and the charge generated in the piezoelectric film 11 when the piezoelectric film 11 is deformed by compressive stress do not cancel each other out. Therefore, the sensitivity of the sensor section 3 is improved. As a result, according to the flow switch 1, the sensitivity for detecting the flow of fluid can be improved.

According to the flow switch 1, the sensor part 3 can be easily fixed to the outer peripheral surface OS of the tube 2 and to the curved part 22. More specifically, the sensor section 3 includes a piezoelectric film 11. Further, the piezoelectric film 11 has a sheet shape. Thereby, the sensor section 3 has flexibility. As a result, according to the flow switch 1, the sensor section 3 can be easily fixed to the outer circumferential surface OS of the tube 2 and to the curved section 22.

According to the flow switch attachment method, the flow switch 1 that can detect the flow of fluid without coming into contact with the fluid to be detected can be attached to the tube 2. More specifically, the tube 2 is flexible and has a curved portion 22. The sensor part 3 is fixed to the outer peripheral surface OS of the tube 2 and to the curved part 22 so that the sensor part 3 detects the deformation of the tube 2. As a result, according to the flow switch attachment method, the flow switch 1 that can detect the flow of fluid can be attached to the tube 2 without coming into contact with the fluid to be detected.

[First modification]
A flow switch 1a according to a first modification of the present invention will be described below with reference to the drawings. FIG. 9 is a side view of the tube 2 to which the sensor section 3 according to the first modification is fixed, viewed from the front. FIG. 10 is a sectional view taken along line BB of the tube 2, sensor section 3, and adhesive 4 according to the first modification. FIG. 11 is a side view of the tube 2 and the sensor section 3 viewed from the front in a state where the sensor section 3 according to the first modification is not fixed to the tube 2. FIG. 12 is a front side view of the tube 2 to which the sensor section 3 according to the first modification is fixed, in a state where water 5 is not flowing inside the tube 2. FIG. 13 is a front side view of the tube 2 to which the sensor section 3 according to the first modification is fixed, with water 5 flowing inside the tube 2. In addition, in FIG. 13, in order to explain how the tube 2 and the sensor section 3 deform, the deformation of the tube 2 and the sensor section 3 is emphasized. Regarding the flow switch 1a according to the first modification, only the parts that are different from the flow switch 1 according to the first embodiment will be explained, and the rest will be omitted.

The flow switch 1a is different from the flow switch 1 in that the sensor section 3 is fixed to the second region A2 of the outer peripheral surface OS of the tube 2, as shown in FIGS. 9 and 10.

By moving the sensor section 3 upward toward the curved section 22 from below the curved section 22 as shown in FIG. , and fixed to the curved portion 22. In this embodiment, the sensor section 3 is fixed to the second region A2 and the curved section 22. The sensor section 3 is fixed to the tube 2 and is slightly extended in the left-right direction. As a result, while the sensor section 3 is fixed to the tube 2, tension is generated in the sensor section 3 to cause it to contract in the first direction DIR1 and in the opposite direction to the first direction DIR1. Thereby, the sensor section 3 can detect the deformation of the tube 2.

When the water 5 begins to flow inside the tube 2, the curved portion 22 deforms due to elastic deformation, as shown in FIG. Thereby, the sensor section 3 is deformed so as to contract in the first direction DIR1. Therefore, the piezoelectric film 11 is compressed in the left-right direction. As a result, the piezoelectric film 11 generates positive charges. A detection signal indicating that the tube 2 has been deformed is transmitted to the signal line.

When the water 5 that was flowing inside the tube 2 begins to stop, the force F that the curved portion 22 was receiving from the water 5 becomes smaller. When the water 5 flowing through the tube 2 completely stops, the force F that the curved portion 22 was receiving from the water 5 becomes zero. As a result, the curved portion 22 deforms due to elastic deformation. More specifically, the curved portion 22 returns to the shape in which water 5 is not flowing through the tube 2 due to elastic deformation. Specifically, the curved portion 22 deforms by elastic deformation so that the diameter of the curved portion 22 becomes smaller. Thereby, the sensor section 3 is deformed so as to expand in the first direction DIR1. Therefore, the piezoelectric film 11 is stretched in the left-right direction. As a result, the piezoelectric film 11 generates negative charges. A detection signal indicating that the tube 2 has been deformed is transmitted to the signal line.

The flow switch 1a as described above also has the same effects as the flow switch 1.

[Second modification]
A flow switch 1b according to a second modification of the present invention will be described below with reference to the drawings. FIG. 14 is a sectional view taken along line BB of the tube 2, sensor section 3, and adhesive 4 according to the second modification. Regarding the flow switch 1b according to the second modification, only the parts that are different from the flow switch 1 according to the first embodiment will be explained, and the rest will be omitted.

The flow switch 1b is different from the flow switch 1 in that the sensor section 3 is fixed across the first area A1 and the second area A2 of the outer peripheral surface OS of the tube 2, as shown in FIG. do.

As shown in FIG. 14, the area of the portion of the outer circumferential surface OS of the tube 2 where the sensor section 3 in the first region A1 is fixed is as shown in FIG. larger than the area of the part.

When the water 5 begins to flow inside the tube 2, the curved portion 22 deforms due to elastic deformation. As a result, the portion of the piezoelectric film 11 fixed to the first region A1 of the outer circumferential surface OS of the tube 2 is deformed so as to extend in the first direction DIR1. On the other hand, the portion of the piezoelectric film 11 fixed to the second region A2 of the outer peripheral surface OS of the tube 2 is deformed so as to contract in the first direction DIR1. Since the area of the first region A1 of the outer peripheral surface OS of the tube 2 where the sensor section 3 is fixed is larger than the area of the second region A2 of the outer peripheral surface OS of the tube 2 where the sensor section 3 is fixed, The piezoelectric film 11 generates negative charges. A detection signal indicating that the tube 2 has been deformed is transmitted to the signal line.

When the water 5 that was flowing inside the tube 2 begins to stop, the force F that the curved portion 22 was receiving from the water 5 becomes smaller. When the water 5 flowing through the tube 2 completely stops, the force F that the curved portion 22 was receiving from the water 5 becomes zero. As a result, the curved portion 22 deforms due to elastic deformation. More specifically, the curved portion 22 returns to the shape in which water 5 is not flowing through the tube 2 due to elastic deformation. Specifically, the curved portion 22 deforms by elastic deformation so that the diameter of the curved portion 22 becomes smaller. As a result, the portion of the piezoelectric film 11 fixed to the first region A1 of the outer circumferential surface OS of the tube 2 is deformed so as to contract in the first direction DIR1. On the other hand, the portion of the piezoelectric film 11 fixed to the second region A2 of the outer peripheral surface OS of the tube 2 is deformed so as to extend in the first direction DIR1. Since the area of the first region A1 of the outer peripheral surface OS of the tube 2 where the sensor section 3 is fixed is larger than the area of the second region A2 of the outer peripheral surface OS of the tube 2 where the sensor section 3 is fixed, The piezoelectric film 11 generates positive charges. A detection signal indicating that the tube 2 has been deformed is transmitted to the signal line.

The flow switch 1b as described above also has the same effects as the flow switch 1.

[Third modification]
A flow switch 1c according to a third modification of the present invention will be described below with reference to the drawings. FIG. 15 is a sectional view taken along line BB of the tube 2, sensor section 3, and adhesive 4 according to the third modification. Regarding the flow switch 1c according to the third modification, only the parts different from the flow switch 1a according to the first embodiment will be explained, and the rest will be omitted.

The flow switch 1c differs from the flow switch 1a in that the sensor section 3 is fixed across the first area A1 and the second area A2 of the outer peripheral surface OS of the tube 2, as shown in FIG. do.

As shown in FIG. 15, the area of the portion of the outer peripheral surface OS of the tube 2 where the sensor section 3 in the second region A2 is fixed is as shown in FIG. larger than the area of the part.

When the water 5 begins to flow inside the tube 2, the curved portion 22 deforms due to elastic deformation. As a result, the portion of the piezoelectric film 11 fixed to the first region A1 of the outer circumferential surface OS of the tube 2 is deformed so as to extend in the first direction DIR1. On the other hand, the portion of the piezoelectric film 11 fixed to the second region A2 of the outer peripheral surface OS of the tube 2 is deformed so as to contract in the first direction DIR1. Since the area of the second region A2 of the outer circumferential surface OS of the tube 2 where the sensor section 3 is fixed is larger than the area of the first region A1 of the outer circumferential surface OS of the tube 2 where the sensor section 3 is fixed, The piezoelectric film 11 generates positive charges. A detection signal indicating that the tube 2 has been deformed is transmitted to the signal line.

When the water 5 that was flowing inside the tube 2 begins to stop, the force F that the curved portion 22 was receiving from the water 5 becomes smaller. When the water 5 flowing through the tube 2 completely stops, the force F that the curved portion 22 was receiving from the water 5 becomes zero. As a result, the curved portion 22 deforms due to elastic deformation. More specifically, the curved portion 22 returns to the shape in which water 5 is not flowing through the tube 2 due to elastic deformation. Specifically, the curved portion 22 deforms by elastic deformation so that the diameter of the curved portion 22 becomes smaller. As a result, the portion of the piezoelectric film 11 fixed to the first region A1 of the outer circumferential surface OS of the tube 2 is deformed so as to contract in the first direction DIR1. On the other hand, the portion of the piezoelectric film 11 fixed to the second region A2 of the outer peripheral surface OS of the tube 2 is deformed so as to extend in the first direction DIR1. Since the area of the second region A2 of the outer peripheral surface OS of the tube 2 where the sensor section 3 is fixed is larger than the area of the first region A1 of the outer peripheral surface OS of the tube 2 where the sensor section 3 is fixed, The piezoelectric film 11 generates negative charges. A detection signal indicating that the tube 2 has been deformed is transmitted to the signal line.

The flow switch 1c as described above also has the same effects as the flow switch 1a.

[Other embodiments]
The flow switch according to the present invention is not limited to the flow switches 1, 1a to 1c, and can be modified within the scope of the gist. Furthermore, the structures of the flow switches 1, 1a to 1c may be combined arbitrarily.

Note that the sensor section 3 does not have to have a rectangular shape when viewed in the vertical direction. The rectangular shape includes a rectangle and a shape that is slightly modified from a rectangle. In this case, the sensor section 3 only needs to have a longitudinal direction extending in the left-right direction. For example, each of the first upper principal surface US1 and the first lower principal surface LS1 is arranged in the normal direction of the first upper principal surface US1 and the first lower principal surface LS1 in a state in which the sensor unit 3 is developed into a plane. It may have an elliptical shape.

Note that the piezoelectric film 11 does not have to have a rectangular shape when viewed in the vertical direction. In this case, the piezoelectric film 11 only needs to have a longitudinal direction extending in the left-right direction. For example, each of the second upper principal surface US2 and the second lower principal surface LS2 is arranged in the normal direction of the second upper principal surface US2 and the second lower principal surface LS2 in a state where the piezoelectric film 11 is developed into a plane. It may have an elliptical shape.

Note that the length of the sensor section 3 in the left-right direction may be the same as the length of the sensor section 3 in the front-back direction. For example, each of the first upper principal surface US1 and the first lower principal surface LS1 is arranged in the normal direction of the first upper principal surface US1 and the first lower principal surface LS1 in a state in which the sensor unit 3 is developed into a plane. In other words, it may have a square or circular shape.

Note that the length of the piezoelectric film 11 in the left-right direction may be the same as the length of the piezoelectric film 11 in the front-back direction. For example, each of the second upper principal surface US2 and the second lower principal surface LS2 is arranged in the normal direction of the second upper principal surface US2 and the second lower principal surface LS2 in a state where the piezoelectric film 11 is developed into a plane. In other words, it may have a square or circular shape.

Note that the piezoelectric film 11 may be a film containing polylactic acid stretched in at least one axis.

Note that the piezoelectric film 11 may have a piezoelectric constant of d31. The piezoelectric film 11 having a piezoelectric constant of d31 is, for example, a PVDF (polyvinylidene fluoride) film. Moreover, the piezoelectric film 11 may be a piezoelectric ceramic.

Note that the polarity of the charge generated by the piezoelectric film 11 when the piezoelectric film 11 is stretched in the left-right direction is the same as the polarity of the charge generated by the piezoelectric film 11 when the piezoelectric film 11 is stretched in the front-back direction. It's okay.

Note that the angles formed by the uniaxial stretching direction OD of the piezoelectric film 11 and each of the front-rear direction and left-right direction are not limited to 45 degrees.

Note that the upper electrode 12a may be a signal electrode, and the lower electrode 12b may be a ground electrode.

Note that the lower electrode 12b may be provided between the upper main surface and the lower main surface of the flexible printed circuit board 14. That is, the lower electrode 12b may be located within the flexible printed circuit board 14.

Note that the flexible printed circuit board 14 is not an essential component.

Note that the tube 2 does not need to have the left straight section 21L and the right straight section 21R.

Note that the fluid is not limited to water 5. The fluid may be, for example, oil or air.

Note that the adhesive 4 is not an essential component.

Note that the curved portion 22 is not limited to being deformed by elastic deformation. The curved portion 22 may be deformed by plastic deformation. Further, the curved portion 22 may be deformed by elastic deformation or plastic deformation. Even in these cases, the same effects as the flow switch 1 can be achieved. Further, a nozzle may be provided at the tip of the tube 2. In this case, a bend 22 is provided on the tube 2 so that the position of the nozzle can be changed. When the position of the nozzle changes, the curved portion 22 is elastically deformed. As a result, the radius of curvature of the curved portion 22 changes. Even in this case, the same effects as the flow switch 1 can be achieved.

Note that the sensor section 3 may detect twisting of the tube 2 in the left-right direction. Further, the deformation direction of the tube 2 detected by the sensor section 3 is not limited to the left-right direction, but may be the up-down direction or the front-back direction, or may be any direction. Moreover, the deformation direction of the tube 2 detected by the sensor section 3 may be a plurality of directions.

Note that the sensor section 3 may detect the amount of deformation or stress of the tube 2. Further, the sensor section 3 may include, for example, a strain gauge.

Note that the outer edge of the cross section of the tube 2 perpendicular to the first direction DIR1 does not have to include a circular shape.

Note that the inner edge of the cross section perpendicular to the first direction DIR1 of the tube 2 does not have to include a circular shape.

Note that the flow switches 1, 1a to 1c may further include an arithmetic circuit that calculates the time when the fluid starts flowing and the time when the fluid starts to stop based on the detection signal output from the lower electrode 12b. For example, a determination value is set in the arithmetic circuit in advance. If the bending portion 22 is significantly deformed due to the operation of an external device installed at the tip of the tube 2 before the fluid starts flowing, the arithmetic circuit detects the detection signal if there is a time when the detection signal exceeds the threshold value. The detection signal at the time when is equal to or greater than the determination value may be masked.

The present invention has the following structure.

(1)
A flow switch that detects the flow of fluid flowing in a tube that is flexible and has a curved part,
The flow switch is
comprising a sensor section that detects deformation of the tube,
The sensor section is fixed to the outer peripheral surface of the tube and the curved section.
flow switch.

(2)
The outer circumferential surface has a first region located in a second direction from the center of the tube, and a second region located in a third direction from the center of the tube, when viewed in the first direction in which the fluid flows. death,
the second direction and the third direction are orthogonal to the first direction,
The third direction is the opposite direction to the second direction,
The curved portion includes a shape that curves so as to protrude in the second direction,
the sensor section is fixed to the first region;
The flow switch described in (1).

(3)
The sensor section is fixed across the first region and the second region,
The area of the portion of the first region to which the sensor portion is fixed is larger than the area of the portion of the second region to which the sensor portion is fixed.
The flow switch described in (2).

(4)
The outer circumferential surface has a first region located in a second direction from the center of the tube, and a second region located in a third direction from the center of the tube, when viewed in the first direction in which the fluid flows. death,
the second direction and the third direction are orthogonal to the first direction,
The third direction is the opposite direction to the second direction,
The curved portion includes a shape that curves so as to protrude in the second direction,
the sensor section is fixed to the second region,
The flow switch described in (1).

(5)
The sensor section is fixed across the first region and the second region,
The area of the portion of the second region to which the sensor portion is fixed is larger than the area of the portion of the first region to which the sensor portion is fixed.
The flow switch described in (4).

(6)
The sensor section includes a piezoelectric film.
The flow switch according to any one of (1) to (5).

(7)
The main surface of the piezoelectric film has a rectangular shape when viewed in the normal direction of the main surface of the piezoelectric film in a state in which the piezoelectric film is developed into a plane.
The flow switch described in (6).

(8)
The polarity of the charge generated by the piezoelectric film when the piezoelectric film is stretched in the left-right direction is different from the polarity of the charge generated by the piezoelectric film when the piezoelectric film is stretched in the front-back direction.
The flow switch according to (6) or (7).

(9)
The piezoelectric film is a film having polylactic acid stretched in at least one axial direction.
The flow switch according to any one of (6) to (8).

(10)
The main surface of the piezoelectric film has a longitudinal direction extending in the left-right direction and a transversal direction extending in the front-rear direction when the piezoelectric film is expanded into a plane,
The uniaxial stretching direction of the piezoelectric film forms an angle of 45 degrees with respect to the left-right direction and the front-back direction when the piezoelectric film is expanded flatly.
The flow switch according to (9).

(11)
the deformation of the tube detected by the sensor unit is bending of the tube;
The flow switch according to any one of (1) to (10).

(12)
The curved portion deforms by elastic deformation or elastic deformation and plastic deformation.
The flow switch according to any one of (1) to (11).

(13)
an outer edge of a cross section of the tube perpendicular to the first direction in which the fluid flows includes a circular shape;
The flow switch according to any one of (1) to (12).

(14)
the fluid is water;
The flow switch according to any one of (1) to (13).

(15)
A flow switch mounting method for mounting a sensor section on a tube that is flexible and has a curved section, the method comprising:
fixing the sensor section to the outer peripheral surface of the tube and the curved section so that the sensor section detects deformation of the tube;
How to install a flow switch.

1, 1a, 1b, 1c: flow switch 2: tube 3: sensor part 4: adhesive 5: water 11: piezoelectric film 12a: upper electrode 12b: lower electrode 13: electrode member 14: flexible printed circuit board 21L: left linear part 21R: Right straight section 22: Curved section A1: First region A2: Second region DIR1: First direction DIR2: Second direction DIR3: Third direction F: Force LS1: First lower main surface LS2: Second lower main surface Surface O: Center OD: Uniaxial stretching direction OS: Outer peripheral surface US1: First upper principal surface US2: Second upper principal surface

Claims

A flow switch that detects the flow of fluid flowing in a tube that is flexible and has a curved part,
The flow switch is
comprising a sensor section that detects deformation of the tube,
The sensor section is fixed to the outer peripheral surface of the tube and the curved section.
flow switch.
The outer circumferential surface has a first region located in a second direction from the center of the tube, and a second region located in a third direction from the center of the tube, when viewed in the first direction in which the fluid flows. death,
the second direction and the third direction are orthogonal to the first direction,
The third direction is the opposite direction to the second direction,
The curved portion includes a shape that curves so as to protrude in the second direction,
the sensor section is fixed to the first region;
Flow switch according to claim 1.
The sensor section is fixed across the first region and the second region,
The area of the portion of the first region to which the sensor portion is fixed is larger than the area of the portion of the second region to which the sensor portion is fixed.
Flow switch according to claim 2.
The outer circumferential surface has a first region located in a second direction from the center of the tube, and a second region located in a third direction from the center of the tube, when viewed in the first direction in which the fluid flows. death,
the second direction and the third direction are orthogonal to the first direction,
The third direction is the opposite direction to the second direction,
The curved portion includes a shape that curves so as to protrude in the second direction,
the sensor section is fixed to the second region,
Flow switch according to claim 1.
The sensor section is fixed across the first region and the second region,
The area of the portion of the second region to which the sensor portion is fixed is larger than the area of the portion of the first region to which the sensor portion is fixed.
The flow switch according to claim 4.
The sensor section includes a piezoelectric film.
The flow switch according to any one of claims 1 to 5.
The main surface of the piezoelectric film has a rectangular shape when viewed in the normal direction of the main surface of the piezoelectric film in a state in which the piezoelectric film is developed into a plane.
The flow switch according to claim 6.
The polarity of the charge generated by the piezoelectric film when the piezoelectric film is stretched in the left-right direction is different from the polarity of the charge generated by the piezoelectric film when the piezoelectric film is stretched in the front-back direction.
The flow switch according to claim 6 or claim 7.
The piezoelectric film is a film having polylactic acid stretched in at least one axial direction.
The flow switch according to any one of claims 6 to 8.
The main surface of the piezoelectric film has a longitudinal direction extending in the left-right direction and a transversal direction extending in the front-rear direction when the piezoelectric film is expanded into a plane,
The uniaxial stretching direction of the piezoelectric film forms an angle of 45 degrees with respect to the left-right direction and the front-back direction when the piezoelectric film is expanded flatly.
The flow switch according to claim 9.
the deformation of the tube detected by the sensor unit is bending of the tube;
The flow switch according to any one of claims 1 to 10.
The curved portion deforms by elastic deformation or elastic deformation and plastic deformation.
The flow switch according to any one of claims 1 to 11.
an outer edge of a cross section of the tube perpendicular to the first direction in which the fluid flows includes a circular shape;
The flow switch according to any one of claims 1 to 12.
the fluid is water;
The flow switch according to any one of claims 1 to 13.
A flow switch mounting method for mounting a sensor section on a tube that is flexible and has a curved section, the method comprising:
fixing the sensor section to the outer peripheral surface of the tube and the curved section so that the sensor section detects deformation of the tube;
How to install a flow switch.