JP2022060652A - Detection unit - Google Patents

Abstract

To provide a detection unit having excellent detection performance and not easily affected by foreign matter flowing in the flow path.SOLUTION: A detection unit 1 of one embodiment includes a body 2 in which a flow path 18 is formed, and a sensor 8 for detecting the flow state of fluid passing through the flow path 18. The sensor 8 is provided integrally with a cylindrical rotating body 4 arranged in the body 2, a plurality of blades 30 extending inward in the radial direction from the inner peripheral surface of the rotating body 4, a plurality of magnets 32 provided integrally with the rotating body 4 and arranged in the circumferential direction, a support portion 6 that is provided integrally with the body 2 and rotatably supports the rotating body 4, and a detector 24 that is provided on the body 2 so that it can face the magnet 32 in the radial direction and detects the rotational state of the rotating body 4 based on changes in the magnetic field due to the plurality of magnets 32. The support portion 6 has an annular support surface 22 that is separated from the axis of the rotating body 4 and rotatably and slidably supports a downstream end portion of the rotating body 4.SELECTED DRAWING: Figure 5

Description

The present invention relates to a detection unit for detecting the flow state of a fluid.

A water heater is generally provided with a detection unit that detects the flow state of hot water (see, for example, Patent Document 1). The detection unit includes a sensor body mounted in the pipe and a sensor for detecting the flow state of the fluid flowing through the sensor body. The sensor includes a rotating body that is rotationally driven by the flow of hot water and a detection unit that detects the rotational state of the rotating body. More specifically, the rotating body has a shaft and a plurality of blades radially arranged from the shaft. N poles and S poles are alternately magnetized on the adjacent blades. The detection unit includes a magnetic sensor embedded in the pipe at the radial outer position of the rotating body.

A rectifier is provided at the upstream end of the sensor body, and a bearing member is provided at the downstream end. Bearings are provided on each of the rectifier and the bearing member to rotatably support the shaft. Hot water that has become a vortex by passing through the rectifier hits these blades and rotates the rotating body. The detection unit detects the rotational state of the rotating body based on the change in the magnetic field accompanying the rotation of the plurality of blades. An opening is provided in the sensor body at a position facing the magnetic sensor to ensure the sensitivity of the magnetic sensor.

Japanese Unexamined Patent Publication No. 2006-317233

In such a water heater, foreign matter may be guided to the detection unit. If fibrous foreign matter wraps around the shaft and the bearing, or if particulate foreign matter accumulates in the bearing holes, it may hinder the smooth rotation of the shaft and hinder accurate detection. .. In some cases, it may lock the rotation of the shaft. It should be noted that such a problem may occur not only in a hot water supply device but also in a detection unit applied to a device for other purposes.

The present invention has been made in view of such a problem, and one of the objects thereof is to provide a detection unit which is excellent in detection performance and is not easily affected by foreign matter flowing in a flow path.

One aspect of the present invention is a detection unit for detecting the flow state of a fluid. The detection unit includes a body in which the flow path is formed and a sensor that detects the flow state of the fluid passing through the flow path. The sensor is provided integrally with a cylindrical rotating body arranged in the body, a plurality of blades extending inward in the radial direction from the inner peripheral surface of the rotating body, and arranged in the circumferential direction. A support portion that is integrally provided with the body and rotatably supports the rotating body, and a support portion that is provided on the body so as to be able to face the magnet in the radial direction based on the change in the magnetic field due to the plurality of magnets. , A detection unit for detecting the rotational state of the rotating body, and the like. The support portion has an annular support surface that is separated from the axis of the rotating body and rotatably and slidably supports the downstream end portion of the rotating body.

According to this aspect, the rotating body has a cylindrical shape and does not have a shaft. Since the shaft does not have a structure supported by the bearing portion, the fibrous foreign matter does not wind around the shaft of the rotating body and hinder the rotation. In addition, particulate foreign matter does not enter the bearing holes. Therefore, the rotating body is not easily affected by foreign matter. Further, since the magnet is arranged in the cylindrical portion of the rotating body, the detection unit and the magnet can be brought close to each other. Therefore, it is easy to maintain high sensitivity of the detection unit.

According to the present invention, it is possible to provide a detection unit having excellent detection performance and being less susceptible to the influence of foreign matter flowing through the flow path.

It is an exploded perspective view which shows the component of a detection unit. It is a figure which shows the structure of the detection unit. It is a figure which shows the structure of a rotating body. It is a figure which shows the structure of a rectifier. It is a figure which shows the assembly structure of a rotating body. It is a partially enlarged sectional view showing the main part of the detection unit which concerns on a modification. It is a figure which shows the main part of the detection unit which concerns on other modification. It is a figure which shows the main part of the detection unit which concerns on other modification. It is a figure which shows the main part of the detection unit which concerns on other modification. It is a figure which shows the main part of the detection unit which concerns on other modification. It is a figure which shows the structure of the rotating body which concerns on other modification. It is a partially enlarged sectional view showing the main part of the detection unit which concerns on other modification. It is a figure which shows the main part of the detection unit which concerns on other modification. It is a figure which shows the operation of the rotation regulation structure.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, for convenience, the positional relationship of the members may be expressed with reference to the illustrated state. Further, with respect to the following embodiments and variations thereof, substantially the same components are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

FIG. 1 is an exploded perspective view showing the components of the detection unit.
The detection unit 1 is configured by assembling a pipe-shaped body 2 so as to accommodate a rotating body 4 and a rectifier 6. The rotating body 4 is a cylindrical impeller and constitutes a sensor 8 described later (see FIG. 2). The rectifier 6 functions as a "rectifier".

FIG. 2 is a diagram showing the configuration of the detection unit 1. (A) is a front view, and (B) is a cross-sectional view taken along the line AA of (A).
The body 2 has a stepped cylindrical shape, and one end portion and the other end portion are expanded to form an introduction pipe portion 10 and a lead-out pipe portion 12, respectively. The introduction pipe portion 10 can be connected to an upstream pipe (not shown) and has an introduction port 14 for introducing a fluid. The outlet pipe unit 12 can be connected to a downstream pipe (not shown) and has a lead-out port 16 for leading the fluid. A linear flow path 18 connecting the introduction port 14 and the outlet port 16 is formed in the body 2.

The body 2 is reduced in diameter at the base end portion of the lead-out pipe portion 12. The reduced diameter portion constitutes a support portion 20 that supports the rotating body 4 from the downstream side. The support portion 20 extends radially inward from the inner peripheral surface of the body 2 in an annular shape, and the upstream side surface thereof constitutes the annular support surface 22. The rotating body 4 is arranged on the upstream side of the support portion 20, and the rectifier 6 is arranged on the upstream side thereof. The rectifier 6 is fixed to the body 2 by crimping the inner peripheral portion of the body 2 near the upstream end of the rectifier 6 (not shown). The crimping joint is realized by, for example, ultrasonic swaying. In the modified example, the rectifier 6 may be press-fitted into the body 2 to be fixed. The rectifier 6 is locked by a step portion formed on the inner peripheral surface of the body 2 and is positioned in the axial direction thereof. The rotating body 4 is slightly displaceable in the axial direction in the space formed between the rectifier 6 and the support portion 20.

The body 2 is also provided with a detection unit 24 at a position radially opposed to the rotating body 4. The detection unit 24 is composed of a magnetic sensor, and for example, a sensor element such as a reed switch or a Hall element that detects a change in a magnetic field can be used. The detection unit 24 and the rotating body 4 constitute the sensor 8. The body 2 constitutes the piping of the hot water supply device, and the intermediate portion thereof also functions as a sensor body. The detection unit 24 only needs to be able to detect the rotational state of the rotating body 4, and the detection method can be appropriately selected. Although the detection unit 24 is embedded in the wall of the body 2, it may be arranged on the outer surface of the body 2.

FIG. 3 is a diagram showing the configuration of the rotating body 4. (A) is a perspective view, (B) is a front view, (C) is a plan view, and (D) is a rear view. (E) is a cross-sectional view taken along the line BB of (B), and (F) is a cross-sectional view taken along the line CC of (B).

The rotating body 4 is obtained by injection molding of a resin material and has a cylindrical main body 28 (FIG. 3 (A)). A plurality of blades 30 extend inward in the radial direction from the inner peripheral surface of the main body 28 (FIG. 3B). The blades 30 are rectangular flat blades, and are provided at equal intervals in the circumferential direction of the main body 28, that is, at intervals of 90 degrees about the axis L (FIG. 3 (F)). However, the blades 30 do not reach the axis L and do not intersect with each other. The blade 30 is not magnetized.

A plurality of magnets 32 are integrally provided on the rotating body 4 (FIG. 3A). The magnet 32 has a rectangular shape in a plan view and is integrated with the main body 28 by insert molding (injection molding) (FIGS. 3 (C) and 3 (E)). Four magnets 32 are provided at equal intervals in the circumferential direction of the main body 28, that is, at intervals of 90 degrees about the axis L. These magnets 32 are provided on the outer peripheral surface of the main body 28 so that N poles and S poles appear alternately along the circumferential direction. The detection unit 24 detects the rotational state of the rotating body 4 based on the change in the magnetic field caused by these magnets 32.

A pair of annular protrusions 34, 36 are provided on the outer peripheral surface of the main body 28 so as to sandwich these magnets 32 in the axial direction (FIGS. 3 (C) and 3 (E)). The protrusion 34 located on the upstream side functions as a "first protrusion", and the protrusion 36 located on the downstream side functions as a "second protrusion". Although the surface of the magnet 32 is exposed from the outer peripheral surface of the main body 28, it is substantially flush with the outer peripheral surface of the main body 28. The protrusions 34 and 36 project outward in the radial direction from the magnet 32. Therefore, even if the protrusions 34 and 36 slide on the inner peripheral surface of the body 2 when the flow rate is low, that is, when the rotating body 4 rotates at a low speed, the magnet 32 is prevented from sliding. Since the contact area between the inner peripheral surface of the body 2 and the rotating body 4 can be reduced, the frictional resistance of the rotating body 4 can be reduced, and the flow rate can be detected even at a low speed.

A plurality of small protrusions 38 are intermittently arranged in an annular shape on the upstream end surface of the main body 28 (FIG. 3 (B)). Six small protrusions 38 are provided at equal intervals in the circumferential direction of the main body 28, that is, at intervals of 60 degrees about the axis L. A plurality of small protrusions 40 are also intermittently arranged in an annular shape on the downstream end surface of the main body 28 (FIG. 3 (D)). In the present embodiment, the small protrusions 40 have the same shape as the small protrusions 38, and are provided at six equal intervals in the circumferential direction of the main body 28, that is, at intervals of 60 degrees about the axis L.

FIG. 4 is a diagram showing the configuration of the rectifier 6. (A) is a perspective view seen from the front side, (B) is a perspective view seen from the back side, (C) is a front view, (D) is a plan view, and (E) is a rear view. (F) is a cross-sectional view taken along the line DD of (C).

The rectifier 6 is obtained by injection molding of a resin material and has a stepped cylindrical main body 42 (FIGS. 4A and 4B). A step is provided on the outer peripheral surface of the main body 42 (FIG. 4 (D)). A shaft portion 44 is provided on the axis L2 of the main body 42, and a plurality of rectifying blades 46 extend outward in the radial direction from the shaft portion 44 (FIGS. 4 (C) and 4 (E)). In this embodiment, five straightening vanes 46 are arranged at equal intervals in the circumferential direction of the shaft portion 44. These straightening vanes 46 have a screw shape twisted around the axis L2, and their respective tips are connected to the inner peripheral surface of the main body 42 (FIG. 4 (F)). In the present embodiment, the shaft portion 44 is provided with a recess 48 that opens to the back side, so-called meat stealing is performed, but this may be omitted.

Returning to FIG. 2B, the rectifier 6 generates a vortex in the vicinity of the upstream side of the rotating body 4 when the fluid flows through the flow path. That is, when the blade 30 is composed of flat blades parallel to the axis L as described above, the fluid flow for rotating the blade 30 needs to be a vortex flow. Therefore, the rectifier 6 is provided with a rectifying blade 46 for forming a vortex flow on the upstream side of the rotating body 4.

The fluid flowing into the rectifier 6 passes through the rectifying blades 46 and becomes a vortex flow corresponding to the twist of the rectifying blades 46, and is guided to the rotating body 4. At this time, when the vortex hits the blade 30, the rotating body 4 rotates at an axial flow velocity of the vortex, that is, a rotation speed corresponding to the flow velocity of the fluid. Then, the flow rate of the fluid passing through the detection unit 1 can be calculated by detecting the change in the magnetic field according to the rotation speed of the rotating body 4 by the detection unit 24.

FIG. 5 is a diagram showing an assembled structure of the rotating body 4. (A) is a partially enlarged cross-sectional view showing the rotating body 4 and its surroundings. (B) is an enlarged view of part E of (A), and (C) is an enlarged view of part F of (A). This figure shows a state in which the fluid is flowing in the forward direction from the upstream side to the downstream side (see the arrow in the figure).

As shown in FIG. 5A, the rotating body 4 is arranged in an operating space 50 formed between the support portion 20 and the rectifier 6. When the fluid flows in the forward direction, the rotating body 4 is displaced to the downstream side of the working space 50 due to the fluid pressure. At this time, the downstream end surface of the main body 28 (the tip surface of the small protrusion 40) abuts on the support surface 22 in the axial direction, and the movement of the rotating body 4 in the axial direction is restricted. The upstream end face of the main body 28 is separated from the downstream end face of the rectifier 6.

The detection unit 24 is provided on the body 2 so as to be able to face the magnet 32 in the radial direction. In the present embodiment, as shown in the figure, there is no independent sensor body between the inner peripheral surface of the body 2 and the rotating body 4. Further, there is no shaft constituting the central axis of the rotating body 4. Therefore, the number of parts is smaller than that of the conventional structure (see Patent Document 1). Further, there is no need for a process such as providing an opening in the sensor body.

The rotating body 4 rotates while the tip surfaces of the plurality of small protrusions 40 slide on the support surface 22. The support surface 22 has an annular surface so as to slidably support a plurality of small protrusions 40 arranged in an annular shape. By intermittently forming the contact surface between the rotating body 4 and the support portion 20 in this way, the sliding resistance of the rotating body 4 is reduced and its smooth rotation is promoted. The support portion 20 has a downstream side shielding portion 52 that protrudes in an annular shape toward the upstream side on the inner side in the radial direction from the support surface 22. The downstream side shielding portion 52 is coaxially inserted inside the downstream side end portion of the main body 28, and radially overlaps the downstream side end portion thereof.

More specifically, as shown in FIG. 5B, when the downstream end surface of the rotating body 4 and the support surface 22 are in contact with each other, the tip of the downstream shielding portion 52 is larger than the base end of the small protrusion 40. The height of the downstream side shielding portion 52 from the support surface 22 is set so as to be located on the upstream side. As a result, it becomes difficult for foreign matter to be guided to the contact portion between the rotating body 4 and the support portion 20.

Returning to FIG. 5A, the rectifier 6 has a locking surface 54 on its downstream end face. When the fluid flows backward from the downstream side to the upstream side, the rotating body 4 is displaced to the upstream side of the working space 50 due to the fluid pressure. At this time, the upstream end surface of the main body 28 (the tip surface of the small protrusion 38) abuts on the locking surface 54 in the axial direction, and the movement of the rotating body 4 in the axial direction is restricted. The downstream end surface of the main body 28 is separated from the support surface 22. That is, the rectifier 6 also functions as a "locking portion" and a "locking member" for locking the movement of the rotating body 4 to the upstream side. When there is no fluid flow, there is a concern that the rotating body 4 may fall out of the body 2 due to gravity depending on the mounting posture of the detection unit 1. However, in the present embodiment, the rectifier 6 is engaged with the “locking portion” and the “locking portion”. By functioning as a "stop member", it is prevented from falling off.

The rectifier 6 has an upstream side shielding portion 56 that projects radially inward from the locking surface 54 toward the downstream side in an annular shape. The upstream side shielding portion 56 is coaxially inserted inside the upstream side end portion of the main body 28, and radially overlaps the upstream side end portion thereof.

More specifically, as shown in FIG. 5C, when the fluid flows in the forward direction, that is, when the upstream end surface of the rotating body 4 and the locking surface 54 are most separated from each other, the upstream shielding portion 56 of the upstream shielding portion 56. The height of the upstream shielding portion 56 from the locking surface 54 is set so that the tip is located on the downstream side of the base end of the small protrusion 38. As a result, it becomes difficult for foreign matter to be guided to the gap between the inner peripheral surface of the body 2 and the rotating body 4.

Next, a method of assembling the detection unit 1 will be described with reference to FIGS. 1 and 2.
As shown in FIG. 1, when assembling the detection unit 1, first, the rotating body 4 is inserted so as to be dropped into the body 2 from the introduction port 14. At this time, the rotating body 4 is held in the body 2 in a state of being supported by the support portion 20 (see FIG. 2B).

Subsequently, the rectifier 6 is inserted from the introduction port 14 so as to be dropped into the body 2. At this time, the rectifier 6 is inserted deeper than the introduction pipe portion 10 and is locked by the step portion formed on the inner peripheral surface of the body 2. In this state, the rectifier 6 is fixed to the body 2 by crimping the inner peripheral portion of the body 2 by ultrasonic aging as described above. As a result, the assembly of the detection unit 1 is completed in the manner shown in FIG. 2 (B).

Next, the operation of the detection unit 1 will be described with reference to FIGS. 2 and 5.
The detection unit 1 shown in FIG. 2 is installed in a target device (for example, a hot water supply device). When this target device is activated, the fluid introduced from the upstream pipe (not shown) via the introduction port 14 becomes a vortex through the rectifier 6 and is guided into the rotating body 4. The rotating body 4 is rotated by the vortex hitting the plurality of blades 30. The fluid that has passed through the rotating body 4 is led out from the outlet port 16 to a downstream pipe (not shown).

The rotating body 4 rotates while its downstream end surface slides on the support surface 22. At this time, in the rotating body 4, when a fluid of a predetermined flow rate or more flows and a sufficient rotational speed is obtained, the fluid existing between the inner peripheral surface of the body 2 and the outer peripheral surface of the rotating body 4 functions as a fluid bearing. However, it maintains a substantially coaxial state with the body 2. In the modified example, such a fluid bearing may not function. Even in that case, since the outer peripheral surface of the rotating body 4 rotates and slides on the inner peripheral surface of the body 2 only at the protrusions 34 and 36, the sliding resistance can be suppressed to a small value.

That is, as shown in FIG. 5, the rotating body 4 basically rotates with the protrusions 34 and 36 floating from the inner peripheral surface of the body 2. Therefore, wear of the protrusions 34 and 36 is prevented or suppressed. The detection unit 24 detects the rotational state (rotational speed) of the rotating body 4 based on the change in the magnetic field due to the rotation of the magnet 32. The flow rate of the fluid can be calculated based on the rotational state of the rotating body 4.

When the operation of the target device is stopped and the flow rate of the fluid becomes small, the rotational force of the rotating body 4 is lost. At this time, the rotating body 4 stops in a state of following gravity. For example, when the detection unit 1 is installed so that the axis of the rotating body 4 is in the horizontal direction, the rotating body 4 is displaced downward in the direction of gravity, and a part of the protrusions 34 and 36 is the inner circumference of the body 2. Contact the surface. In some cases, the rotating body 4 touches the axis of the body 2 and slides on the inner peripheral surface of the body 2. Even in such a case, since the protrusions 34 and 36 project from the outer peripheral surface of the main body 28, it is possible to prevent the magnet 32 from being worn.

As described above, according to the present embodiment, there is provided a novel detection unit 1 in which the rotating body 4 has a cylindrical shape and floats and rotates from the inner peripheral surface of the body 2. Even if the floating is not sufficient, the sliding resistance between the outer peripheral surface of the rotating body 4 and the inner peripheral surface of the body 2 can be suppressed to a small value. The rotating body 4 does not have a shaft, unlike the conventional configuration (see Patent Document 1). Moreover, it does not have a bearing portion that supports the shaft. The support portion 20 is separated from the axis L of the rotating body 4. That is, since the shaft does not have a structure supported by the bearing portion, the fibrous foreign matter does not wind around the shaft of the rotating body and hinder the rotation. In addition, particulate foreign matter does not enter the bearing holes.

Further, the downstream shielding portion 52 is arranged inside the downstream end portion of the rotating body 4, and the upstream shielding portion 56 is arranged inside the upstream end portion of the rotating body 4. By providing the overlapping shielding portions at both ends of the rotating body 4 in this way, it is possible to prevent foreign matter from entering the sliding portion of the rotating body 4 or wrapping around to the outside of the rotating body 4. As a result, it is possible to prevent the rotating body 4 from malfunctioning due to the accumulation of foreign matter or the like. According to this embodiment, the foreign matter resistance of the detection unit can be improved.

Further, as can be seen by comparing the detection unit 1 shown in FIG. 2B with the detection unit of Patent Document 1, since the bearing portion for supporting the shaft is not required in this embodiment, the body of the detection unit The total length can be shortened. As a result, the entire detection unit can be compactly configured. There is also an advantage that the material cost can be reduced by shortening the body. According to this embodiment, it is possible to deal with problems such as miniaturization of the detection unit and space saving of the target device.

Further, since the magnet 32 is arranged on the main body 28 (cylindrical portion) of the rotating body 4, the detection unit 24 and the magnet 32 can be brought close to each other. Therefore, it is easy to maintain high sensitivity of the detection unit 24. That is, according to the present embodiment, it is possible to provide a detection unit having excellent detection performance.

(Modification example)
FIG. 6 is a partially enlarged cross-sectional view showing a main part of the detection unit according to the modified example. (A) shows the first modification example, and (B) shows the second modification example.
In the first modification, the ring-shaped support member 122 is assembled to the support portion 120 (FIG. 6A). The support member 122 is made of a material having a lower sliding resistance than the body 102. The support member 122 may be a washer-shaped metal component whose surface is lubricated and plated. As the lubricating plating, a known lubricating plating material such as nickel-phosphorus (Ni-P) containing polytetrafluoroethylene (PTFE) can be applied.

The support member 122 is press-fitted into a recess formed between the inner surface of the body 102 and the downstream shielding portion 52. The upstream end surface of the support member 122 is the support surface 22. According to this modification, the durability of the sliding portion of the rotating body 4 can be improved. When performing wear resistance treatment such as lubrication plating, it may be applied to the entire support member 122 or only to the support surface 22 as described above.

In the second modification, the rectifying portion 106 is integrally molded with the body 104. On the other hand, the support member 124 is assembled on the downstream side of the body 104 and functions as a "support portion". The rectifying unit 106 has a rectifying blade 46 similar to that of the rectifier 6, and generates a vortex flow to be supplied to the rotating body 4. The straightening vane 106 has a locking surface 54 and an upstream shielding portion 56 at a downstream end portion radially outside the straightening vane 46. The support member 124 has a stepped cylindrical shape in which the outer diameter gradually decreases toward the upstream side, and the upstream end surface thereof is a support surface 22. A downstream side shielding portion 52 is provided inside the support surface 22. The support member 124 is locked by a step portion formed on the inner peripheral surface of the body 104, and is positioned in the axial direction thereof. An annular retaining member 126 is provided on the downstream side of the support member 124.

When assembling the detection unit of this modification, the rotating body 4 is inserted so as to be dropped into the body 104 from the lead-out port (downstream port). At this time, the rotating body 4 is held in the body 104 in a state of being supported by the rectifying unit 106. Subsequently, the support member 124 is inserted so as to be dropped into the body 104 from the lead-out port. After that, the retaining member 126 is press-fitted inward of the body 104 from the lead-out port side. As a result, the support member 124 is fixed to the body 104.

FIG. 7 is a diagram showing a main part of the detection unit according to another modification. (A) is a partially enlarged cross-sectional view of the detection unit. (B) is a front view of a rotating body.
In the third modification, the torsion blade 230 is adopted as the blade of the rotating body 204. A shaft portion 210 extending along the axis L of the main body 28 is provided, but there is no bearing portion that supports the shaft portion 210. A plurality of torsion blades 230 extend inward in the radial direction from the inner peripheral surface of the main body 28. The twisting blades 230 are blades twisted in a screw shape, and in this modification, they are provided at four, that is, at intervals of 90 degrees about the axis L. Each torsion blade 230 is connected to a shaft portion 210.

According to this modification, since a plurality of torsion blades 230 are adopted for the rotating body 204, the rotating body 204 autonomously rotates when the fluid from the upstream side hits each twisting blade 230. Therefore, a rectifying unit (rectifier) is not required on the upstream side of the rotating body 204. Therefore, a locking member 206 having no rectifying blade is provided on the upstream side of the rotating body 204. The locking member 206 has a stepped cylindrical shape in which the outer diameter gradually decreases toward the downstream side, and the downstream end surface thereof is a locking surface 54. An upstream shielding portion 56 is provided inside the locking surface 54. The locking member 206 is locked by a step portion formed on the inner peripheral surface of the body 2 and is positioned in the axial direction thereof. The locking member 206 locks the movement of the rotating body 204 to the upstream side.

FIG. 8 is a diagram showing a main part of the detection unit according to another modification.
In the fourth modification, the locking portion 208 is integrally molded with the body 202. A locking surface 54 and an upstream shielding portion 56 are provided at the downstream end of the locking portion 208. On the other hand, as in the second modification, the support member 124 and the retaining member 126 are assembled on the downstream side of the rotating body 204 in the body 202.

FIG. 9 is a diagram showing a main part of the detection unit according to another modification. (A) is a partially enlarged cross-sectional view of a main part. (B) is an enlarged view of part E of (A), and (C) is an enlarged view of part F of (A).
In the fifth modification, the small protrusion 40 on the downstream side is provided on the support portion 320 (body 302) instead of the rotating body 304 (FIG. 9A). A downstream side shielding portion 352 that annularly protrudes from the inner peripheral edge of the support portion 320 toward the upstream side is provided (FIG. 9B). A plurality of small protrusions 40 are intermittently arranged in an annular shape on the tip surface of the downstream side shielding portion 352. An annular recess 330 along the inner peripheral edge is provided on the downstream end surface of the main body 328, and the bottom surface of the annular recess 330 is annularly supported by a plurality of small protrusions 40. That is, the tip surface of these small protrusions 40 functions as the support surface 22. Although the downstream side shielding portion 352 cannot exert a complete shielding effect on foreign matter due to the intermittent arrangement of the small protrusions 40, it is possible to prevent the foreign matter from wrapping around to the outside of the rotating body 304.

Further, the small protrusion 38 as in the above embodiment is not provided on the upstream side of the main body 328. An annular recess 340 along the inner peripheral edge is provided on the upstream end surface of the main body 328, and the bottom surface of the annular recess 340 is annularly supported by the downstream end surface of the rectifier 6. In this modification, the tip surface of the upstream shielding portion 56 in the rectifier 6 functions as the locking surface 54. At the time of backflow, the annular recess 340 comes into contact with the locking surface 54. Further, when there is no fluid flow, the annular recess 340 may come into contact with the locking surface 54 depending on the mounting posture of the detection unit 1. However, in these cases, it is not necessary to detect the flow rate and the need to rotate the rotating body 304 is low, so that the sliding resistance between the rectifier 6 and the rotating body 304 does not matter so much. Therefore, in this modification, the sliding resistance reduction structure by small protrusions is omitted on the upstream side. Since the upstream side shielding portion 56 has no small protrusions, it is easy to exert a shielding effect against foreign matter. In particular, when the upstream shielding portion 56 locks the rotating body 304, a complete shielding effect is exhibited.

FIG. 10 is a diagram showing a main part of the detection unit according to another modification. (A) is a partially enlarged cross-sectional view of the detection unit. (B) is a rear view of a rotating body.
In the sixth modification, the small protrusion 440 on the downstream side and the small protrusion 438 on the upstream side of the rotating body 404 are arranged radially inward from the above embodiment. A downstream side shielding portion 452 that annularly protrudes from the inner peripheral edge of the support portion 420 toward the upstream side is provided (FIG. 10 (A)). The tip surface of the downstream side shielding portion 452 is an annular flat surface.

On the other hand, an annular recess 430 along the inner peripheral edge is provided on the downstream end surface of the main body 428, and a plurality of small protrusions 440 are arranged in an annular shape on the bottom surface of the annular recess 430 (FIG. 10 (B)). These small protrusions 440 are rotatably and slidably supported by the annular tip surface of the downstream side shielding portion 452. That is, the annular tip surface of the downstream side shielding portion 452 functions as the support surface 22. The downstream side shielding portion 452 cannot exert a complete shielding effect against foreign matter due to the intermittent arrangement of the small protrusions 440, but can prevent the foreign matter from wrapping around to the outside of the rotating body 404.

Similarly, an annular recess 432 along the inner peripheral edge is provided on the upstream end surface of the main body 428, and a plurality of small protrusions 438 are arranged in an annular shape on the bottom surface of the annular recess 432. When the fluid flows backward, the tip surface of the upstream side shielding portion 56 in the rectifier 6 functions as a locking surface 54, locks these small protrusions 438, and restricts the movement of the rotating body 404 in the axial direction. When there is no fluid flow, there is a concern that the rotating body 404 may fall out of the body 2 due to gravity depending on the mounting posture of the detection unit. By functioning as a "stop member", it is prevented from falling off.

FIG. 11 is a diagram showing a configuration of a rotating body according to another modification. (A) is a front view of the rotating body, (B) is a cross-sectional view taken along the line OH of (A), and (C) is a cross-sectional view taken along the line I-I (upside down) of (A).
In the seventh modification, the structure of the blades in the rotating body 504 is different from that of the above embodiment. The rotating body 504 has two types of blades 30 and 530 having different sizes. Both the length and the height of the blade 530 are smaller than the blade 30. In this modification, two blades 30 and 530 are alternately arranged in the circumferential direction along the inner peripheral surface of the main body 28. One of the two blades 530 is provided closer to the upstream side, and the other is provided closer to the downstream side. That is, as a plurality of blades, blades having different extending positions in the axial direction are included.

By including the blades having different lengths in the axial direction and the lengths in the radial direction as a plurality of blades in the rotating body in this way, the flow of the fluid passing through the rotating body can be adjusted. Thereby, the rotation speed of the rotating body with respect to the flow velocity can be adjusted, and the waveform of the detection signal output by the detection unit can be suitably adjusted for the flow rate calculation. This modification can be applied to any of the rotating bodies of the above-described embodiment and the modification.

In this modification, an example of the number, shape, size, arrangement, combination, etc. of the blades is shown, but these can be changed as appropriate. For example, the plurality of blades may have different sizes. The axial positions of the plurality of blades may be different from each other. When the straightening vane is not provided on the upstream side of the rotating body, all or a part of the plurality of blades may be twisted blades. By including relatively small blades among the plurality of blades, the weight of the rotating body can be reduced and the sliding load thereof can be reduced. It is also possible to reduce the pressure loss of the fluid passing through the detection unit.

FIG. 12 is a partially enlarged cross-sectional view showing a main part of the detection unit according to another modification.
In the eighth modification, a communication passage 610 that penetrates the support portion 420 in the axial direction is provided. The communication passage 610 is located radially outside the support surface 22, and communicates the space outside the radial direction of the rotating body 404 in the working space 50 with the space downstream of the rotating body 404 in the flow path 18. According to this modification, even if a foreign substance enters the space outside the rotating body 404, it can be discharged to the downstream side via the communication passage 610.

In this modification, the configuration in which the communication passage 610 is applied to the sixth modification is illustrated, but it goes without saying that the configuration may be applied to the above-described embodiment and other modifications. In this modification, the communication passages 610 are provided as small circular holes at two locations of the support portion 420, but the number, shape, size, etc. of the communication passages 610 are not limited to this. When the "support portion" is separate from the body as a support member as in the second modification, a communication passage may be provided in the support member. Alternatively, it may be formed between the body and the support member. For example, it can be realized by providing a communication groove on either one or both of the inner peripheral surface of the body and the outer peripheral surface of the support member.

FIG. 13 is a diagram showing a main part of the detection unit according to another modification. (A) is a perspective view, (B) is a plan view, and (C) is a sectional view taken along the line JJ of (B).
In the ninth modification, a rotation restricting structure for restricting the rotation of the rotating body 4 at the time of backflow is provided. This rotation restricting structure is realized by the uneven shape provided on the axially facing surfaces of the rotating body 4 and the rectifier 706 (rectifying unit) (FIGS. 13A and 13B). A recess 710 is formed on the surface of the rectifier 706 facing the small protrusion 38. The concave portion 710 has a width larger than that of the small protrusion 38 and can be loosely fitted with the small protrusion 38. The wall at the widthwise end of the recess 710 functions as a locking surface 712 (second locking surface) (FIG. 13 (C)).

FIG. 14 is a diagram showing the operation of the rotation regulation structure. (A) shows the state at the time of forward flow, and (B) shows the state at the time of backflow.
When the fluid flows in the forward direction, the rotating body 4 rotates with the downstream end portion (small protrusion 40) in contact with the support surface 22 (FIG. 14A). At this time, the small protrusion 38 is in a state of being separated from the recess 710, and the rotation restriction structure does not function.

On the other hand, when the fluid flows backward, the small protrusion 38 is loosely fitted in the recess 710 (FIG. 14 (B)). At this time, even if the rotating body 4 tries to rotate, it is locked by the locking surface 712. That is, the rotation restricting structure functions to restrict the rotation of the rotating body 4. Since the detection unit does not specify the flow direction of the fluid, it is necessary to prevent erroneous detection of the flow rate during backflow as the flow rate during normal flow (forward flow). In this modification, since the rotation of the rotating body 4 itself is restricted during backflow, such erroneous detection can be prevented. According to this modification, it is possible to deal with the problem of preventing erroneous detection at the time of backflow in the detection unit.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the specific embodiment, and it goes without saying that various modifications can be made within the scope of the technical idea of the present invention. Nor.

In the above embodiment, a configuration in which the main body of the rotating body and the magnet are integrally molded is exemplified. In the modified example, the magnet may be integrally fixed after molding the main body. That is, "the magnet is provided integrally with the rotating body" means that the magnet is integrated at the same time as the molding of the main body, or that the main body and the magnet are manufactured separately and then assembled and integrated. including.

In the above embodiment, a configuration in which the detection unit and the body are integrally molded is illustrated. In the modified example, the detection unit may be integrally fixed after the body is molded. That is, "the detection unit is provided integrally with the body" means that the detection unit is integrated at the same time as the molding of the body, and that the body and the detection unit are manufactured separately and then assembled and integrated. Including the case of doing.

In the above embodiment, an example is shown in which protrusions 34, 36 (protrusions) continuous in an annular shape are provided on both sides of the magnet 32 in the axial direction on the outer peripheral surface of the rotating body 4. In the modified example, a plurality of such protrusions may be provided on at least one of the upstream side and the downstream side of the magnet 32, for example. Further, a part or all of the protrusions may be formed in an intermittent annular shape. In that case, the projecting pieces forming the annular shape may extend in the circumferential direction or may extend in the axial direction (parallel to the axial line). A projecting piece extending in the circumferential direction and a projecting piece extending in the axial direction may be mixed.

In the above embodiment, the configuration in which the surface of the magnet 32 is substantially flush with the outer peripheral surface of the main body 28 is exemplified. In the modified example, the surface of the magnet 32 may be slightly projected from the outer peripheral surface of the main body 28. Even in that case, the protruding height of the magnet 32 is set to be smaller than the protruding height of the protrusions 34 and 36. Alternatively, the magnet 32 may be embedded in the main body 28. However, the thickness of the resin portion covering the surface of the magnet 32 is reduced so that a sufficient magnetic field can be obtained by the detection portion 24.

In the above embodiment, the upstream side shielding portion is inserted into the upstream side end portion of the rotating body, and the downstream side shielding portion is inserted into the downstream side shielding portion of the rotating body. Then, the axial length (overlap length) of the nested portions on the upstream side and the downstream side was made larger than the maximum displacement in the axial direction of the rotating body. As such, the structure and arrangement of the rotating body, the support portion and the locking portion (rectifier) were set. This makes it possible to reliably prevent the rotating body from falling out of the support portion or the rectifier even when there is no fluid flow, that is, even when the rotation speed of the rotating body is small.

In the above embodiment, the clearance between the protrusions (first and second protrusions) provided on the outer peripheral surface of the rotating body and the inner peripheral surface of the body is the diameter between the upstream end portion and the upstream shielding portion of the rotating body. It was made smaller than either the directional gap and the radial gap between the downstream end of the rotating body and the downstream shielding portion. For this reason, even if the rotating body shifts downward in the direction of gravity due to a decrease in the number of rotations and the coaxiality with each shielding portion is deviated, the rotating body does not fall off from each shielding portion, and the fluid flows again to the shielding portion. Coaxiality can be restored. Therefore, even if the length of the nested portion described above cannot be secured, the normal rotation of the rotating body can be resumed.

In other words, if the length of the nested portion described above can be secured, the minimum clearance between the outer peripheral surface of the rotating body and the inner peripheral surface of the body can be set as the radial gap and rotation between the upstream end portion and the upstream shielding portion of the rotating body. It can be larger than the radial gap between the downstream end of the body and the downstream shield. In that case, even if the rotating body is offset downward in the direction of gravity due to a decrease in the number of rotations and the coaxiality with each shielding portion is deviated, the rotating body is supported by each shielding portion, so that the rotating body is prevented from falling off. Since the rotating body does not slide on the inner peripheral surface of the body in the first place, it is not necessary to provide a protrusion on the outer peripheral surface thereof.

In the above embodiment, an example is shown in which the downstream end portion of the rotating body is brought into contact with the support portion in the axial direction. In the modified example, the downstream end portion of the rotating body and the support portion may be brought into contact with each other in the radial direction. Specifically, the outer peripheral surface of the downstream side shielding portion inserted into the downstream side end portion of the rotating body may function as a support surface. Further, both ends of the rotating body may be supported by using the outer peripheral surface of the downstream shielding portion as the first bearing surface and the outer peripheral surface of the upstream shielding portion as the second bearing surface. Even if such a configuration is adopted, the support portion is separated from the axis of the rotating body. Since the shielding effect of the shielding portion can be obtained, it is possible to prevent or suppress the wrapping of foreign matter around the rotating body and the accumulation of foreign matter in the rotating sliding portion.

In the above embodiment, the pipe joint is used as the body of the detection unit. The body of the detection unit is not limited to the piping shape. In the modified example, a flow path may be formed in the resin block to form the body of the detection unit. Further, the material of the body is not limited to resin, and may be made of other materials such as stainless steel.

In the above embodiment, a skin piece or hair is assumed as a foreign substance invading the detection unit, but good foreign substance resistance can be obtained even for a plastic piece or other foreign matter.

The configurations of the above embodiments and modifications can also be applied to a detection unit (for example, see Japanese Patent Application Laid-Open No. 2015-194455) in which the rotating body is rotated by a vortex when the hot water supply device is reheated.

The present invention is not limited to the above-described embodiment or modification, and the components can be modified and embodied within a range that does not deviate from the gist. Various inventions may be formed by appropriately combining a plurality of components disclosed in the above-described embodiments and modifications. In addition, some components may be deleted from all the components shown in the above embodiments and modifications.

1 Detection unit, 2 body, 4 rotating body, 6 rectifier, 8 sensor, 14 introduction port, 16 outlet port, 18 flow path, 20 support part, 22 support surface, 24 detector part, 30 blades, 32 magnets, 34 protrusions , 36 protrusion, 38 small protrusion, 40 small protrusion, 46 rectifying blade, 50 working space, 52 downstream side shielding part, 54 locking surface, 56 upstream side shielding part, 102 body, 104 body, 106 rectifying part, 120 support Part, 122 support member, 124 support member, 202 body, 204 rotating body, 206 locking member, 208 locking part, 230 torsion blade, 302 body, 304 rotating body, 320 support part, 352 downstream side shielding part, 404 rotation Body, 420 support, 438 small protrusions, 440 small protrusions, 452 downstream shields, 504 rotating bodies, 530 blades, 610 passages, 706 rectifiers, 710 recesses, 712 locking surfaces, L axis, L2 axis.

Claims (13)

A detection unit for detecting the flow state of a fluid.
The body with the flow path and
A sensor that detects the flow state of the fluid passing through the flow path, and
Equipped with
The sensor is
A cylindrical rotating body disposed in the body and
A plurality of blades extending inward in the radial direction from the inner peripheral surface of the rotating body, and
A plurality of magnets provided integrally with the rotating body and arranged in the circumferential direction,
A support portion provided integrally with the body and rotatably supporting the rotating body,
A detection unit provided on the body so as to be able to face the magnet in the radial direction and detecting the rotational state of the rotating body based on changes in the magnetic field due to the plurality of magnets.
Including
The detection unit is characterized by having an annular support surface that is separated from the axis of the rotating body and rotatably and slidably supports the downstream end portion of the rotating body. The detection unit according to claim 1, wherein the support surface abuts in the axial direction with the downstream end surface of the rotating body when the fluid flows in the forward direction. The detection unit according to claim 2, wherein a plurality of protrusions are intermittently arranged in an annular shape on the downstream end surface of the rotating body, and the tip surface of the protrusions abuts on the support surface. The claim is characterized in that a plurality of protrusions are intermittently arranged in an annular shape on the upstream end surface of the support portion, and the tip end surface of the protrusions abuts on the downstream end surface of the rotating body as the support surface. 2. The detection unit according to 2. Any of claims 2 to 4, wherein the support portion has a downstream side shielding portion that protrudes in an annular shape toward the upstream side and is coaxially inserted inside the downstream side end portion of the rotating body. The detection unit described in. 2. The detection unit according to any one of 5. A locking portion provided integrally with the body is further provided on the upstream side of the rotating body.
The locking portion has a locking surface facing the upstream end surface of the rotating body in the axial direction.
The locking surface can regulate the movement of the rotating body to the upstream side in the axial direction by abutting on the upstream end surface, and is separated from the upstream end surface of the rotating body when the fluid flows in the forward direction. The detection unit according to any one of claims 2 to 6. The detection according to claim 7, wherein the locking portion has an upstream-side shielding portion that protrudes in an annular shape toward the downstream side and is coaxially inserted inside the upstream-side end portion of the rotating body. unit. 7. Detection unit. Any of claims 7 to 9, wherein the locking portion has a rectifying portion having a plurality of rectifying blades that vortex the fluid and guide the fluid to the rotating body on the inner side in the radial direction with respect to the locking surface. The detection unit described in. The support portion is integrally molded with the body by a resin material.
The locking portion is a locking member different from the body.
The detection unit according to any one of claims 7 to 10, wherein the rotating body and the locking member are sequentially dropped from an upstream port of the body toward the support portion. A first protrusion that is annularly projected on the outer peripheral surface of the rotating body at a position on the upstream side of the magnet.
A second protrusion that is annularly projected on the outer peripheral surface of the rotating body at a position on the downstream side of the magnet, and a second protrusion.
Have,
The detection unit according to any one of claims 1 to 11, wherein the first protrusion and the second protrusion protrude outward in the radial direction from the magnet. The detection unit according to any one of claims 1 to 12, wherein the magnet is integrally provided with the rotating body by insert molding of a resin material.

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