JP5103256B2 - Flow sensor - Google Patents

Description

  The present invention relates to a so-called axial flow type flow sensor, and relates to a configuration in which an axial core fixed to an impeller is rotatably supported.

  Conventionally, an impeller is rotatably provided in the flow path coaxially with the water flow, and the rotational speed of the impeller is measured by a combination of a magnet and a magnetic sensor attached to the impeller, and the amount of water can be calculated from the rotational speed. A so-called axial flow type flow sensor is known, and is used in a measuring unit of a water meter, and is used for notifying a filter replacement time by applying to a water purifier (for example, Patent Document 1 and 2).

  In each of the flow sensors disclosed in Patent Documents 1 and 2, one end of the shaft core is fixed to the center of the hub provided on the secondary side (downstream side) of the sensor case forming the flow path so as not to rotate. It is the structure which supported the impeller with a magnet on the other end side of a core so that rotation was possible.

Japanese Patent Laid-Open No. 5-99711 JP 2007-178245 A

  In the flow sensors of Patent Documents 1 and 2, the shaft core is fixed in a so-called cantilever shape. When the shaft core is fixed in a cantilever shape in this way, it is common to fix one end of the hub by press-fitting or insert molding in the center of the hub, but to do this in a narrow sensor case, Since it cannot be done at least by human power and requires a dedicated manufacturing apparatus or a complicated manufacturing process, the manufacturing cost increases. In order to improve the measurement accuracy of the water flow rate, it is necessary to make the shaft core and the flow path axis completely coincide with each other. However, since the shaft core is fixed in a cantilever shape, the shaft core is connected to the flow path. On the other hand, there was a risk of being fixed obliquely. Furthermore, since the impeller can not only rotate in the circumferential direction on the shaft core but also slide in the axial direction, the impeller slides on the shaft core due to vibration or changes in water flow, etc. There was also a risk of influence.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a flow sensor that is excellent in durability and capable of highly accurate measurement without complicating the configuration. is there.

In order to achieve the above-described object, the present invention has a casing that forms a flow path, a water passage around the shaft hole, and the shaft holes on the primary and secondary sides of the flow path. A pair of bearings arranged facing each other, an impeller positioned between the pair of bearings and accommodated in the flow path, a magnet provided integrally with the impeller, and a part of the casing A magnetic sensor that detects rotation of the magnet and a rotation shaft that integrally protrudes from both end faces of the impeller, and the rotation shaft is rotatably supported in the shaft hole portion of the bearing . In the flow rate sensor, the rotating shaft includes a resin-made protrusion protruding from one end face of the impeller and a shaft bar protruding from the opposite end face of the impeller, and the protrusion includes the protrusion Molded integrally with a plastic cap that houses a magnet and can be attached to one end face of an impeller Ri, on the peripheral surface of the resin cap with means of forming a window for transmitting the magnetic force of the magnet. In this means, the impeller and the rotating shaft rotate integrally.

  And although all the bearings can be comprised from resin, it is preferable to make a shaft hole part into a metal at least. This is in consideration of wear resistance. On the other hand, even if the shaft rod is made of resin, it can be replaced simultaneously with the impeller, so that maintenance is easy. However, if the shaft rod is made of metal, the rotating shaft can be made stronger than that of resin.

  Furthermore, it is preferable that at least the secondary shaft is sharp or spherical. This is because the frictional resistance with the bearing is small and the impeller rotates easily. Moreover, when both shaft ends have the above-mentioned shape, core blurring can be prevented by the principle of topping.

  Moreover, it is preferable that the bearing is provided with rectifying blades radially from the shaft hole. In this case, the space between the rectifying blades becomes a water flow portion, and the flowing water passing therethrough is rectified.

  In addition, it is preferable that the flow sensor of this invention can be incorporated in a water purifier so that the integrated flow rate of purified water may be measured. It is because it can alert | report easily the filter replacement time of a water purifier by applying in this way.

  According to the present invention, since the rotating shaft is provided integrally with the impeller, the water flow sensor can be easily assembled using this as one member. In addition, since the rotating shaft is pivotally supported at both ends by two bearings, it can be positioned more reliably as the center axis of the flow path than when only one end is pivotally supported in a cantilever shape. With accurate centering, the impeller can be rotated more accurately according to the flow rate. Furthermore, since the impeller does not slide on the rotating shaft, the water flow is always received under the same conditions, and high accuracy and stable measurement are possible.

  In addition, since one side of the rotating shaft is provided with a resin protrusion from one end face of the impeller, the impeller and the protrusion can be integrally formed by a conventional resin molding method. One side can be easily configured. In addition, since the resin cap that can accommodate the magnet is attached to the impeller, the impeller and the magnet can be easily integrated with this cap, and the protrusion is formed integrally with the cap. Can be configured easily. Further, since the opposite rotation shaft is made of a metal shaft rod, it has excellent wear resistance.

  Furthermore, since the shaft hole is made of metal in the bearing that pivotally supports the shaft rod, the shaft hole can be prevented from being worn over time.

  Furthermore, since the shaft tip of the rotating shaft is sharp or spherical, the frictional resistance with the shaft hole is reduced, the impeller can be rotated even with a small flow rate, and a large measurement range can be secured. In addition, since the shaft tip is sharp or spherical, the impeller having this as the rotation shaft is stable in contact with the shaft hole portion, that is, the rotation fulcrum, as seen in the rotation of the top, so there is no core blurring. Rotate in state. Therefore, stable measurement is possible.

  In addition, for those with rectifying blades provided radially from the shaft hole, the rectifying function can be integrated with the bearing, the configuration is rationalized, and even if a large flow rate or flow rate change occurs, the occurrence of turbulence is suppressed. The impeller can always be rotated at a speed commensurate with the flow rate.

  Furthermore, since the flow sensor of the present invention can be reduced in size, it can be easily incorporated into, for example, a small water purifier attached to a water faucet. It is possible to accurately notify the filter replacement time.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a flow sensor showing a first embodiment of the present invention. In the figure, 1 is a casing, 2 is an impeller, 3 is a magnet, 4 is a box of a magnetic sensor (not shown).

  The casing 1 has a substantially cylindrical shape formed with a linear flow path 1a in which the impeller 2 can be accommodated, and a bearing 1b is integrally formed on the secondary side (downstream side) of the flow path 1a. Do it. The bearing 1b has a shaft hole 1b formed on the central axis of the flow path, and a plurality of rectifying blades 1c formed radially around the shaft hole 1b. Between the rectifying blades 1c, it functions as a water flow portion for water discharge. Further, the shaft hole portion 1b has a recess 1d formed at the center of the primary side end surface thereof, and the outer peripheral surface thereof is parallel to the tapered inner peripheral surface 1e of the flow passage 1a of this portion, so that the interval between them is equal. It is formed in a conical shape. This is to prevent the turbulent flow by making the water pressure constant when passing between the rectifying blades 1c (water passage portion).

  The impeller 2 is provided with a plurality of spiral blades 2a capable of converting hydraulic power into rotational force on the outer peripheral surface, and is formed of, for example, synthetic resin. Here, a cap 5 is detachably attached to the secondary side end face of the impeller 2. The cap 5 has a space in which the magnet 3 can be accommodated and is integrally attached and fixed to the impeller 2. The cap 5 rotates the magnet 3 integrally with the impeller 2. A projection 5a that can be pivotally supported in the shaft hole 1b of the bearing 1b is integrally formed at the center of the secondary side end face of the cap 5. The protrusion 5a constitutes a rotation shaft on the secondary side of the impeller 2, and in this embodiment, the shaft tip is sharp. Note that a window 5 b for transmitting the magnetic force of the magnet 3 is formed on the peripheral surface of the cap 5.

  On the other hand, a shaft rod 6 made of metal such as stainless steel is embedded in the axial direction at the opposite end face of the impeller 2, that is, the center of the primary end face. The shaft 6 constitutes a rotating shaft on the opposite end surface of the impeller 2 by embedding a part of the secondary side in the impeller 2 and partially exposing the primary side. The shaft rod 6 may be made of resin. The shaft rod 6 is embedded by press-fitting or insert molding if the embedded portion of the shaft rod 6 does not easily come out of the impeller 2. However, embedding by press fitting is the simplest and advantageous in terms of cost.

  Furthermore, the bearing 7 of the shaft rod 6 is disposed on the primary side (upstream side) of the flow path 1a. This bearing 7 is provided with a shaft hole portion 7a in which the exposed portion of the shaft rod 6 is pivotally inserted so that the exposed portion of the shaft rod 6 can be pivotally supported. 7b is a wheel shape formed radially. A space between the rectifying blades 7b functions as a water inlet for entering water. In this embodiment, the bearing 7 is formed as a separate member from the casing 1 and is configured to be detachably fitted to the primary side of the flow path 1a. As with the secondary bearing 1, the bearing 7 also has the inner and outer peripheral surfaces of the water passage portion parallel to each other, and the water pressure in this portion is constant by making the entire area of the water passage portion the same diameter. To prevent the occurrence of turbulent flow.

  The flow rate sensor having the above-described configuration has a cap 5 (magnet 3) and a primary shaft 6 assembled in advance to the impeller 2, and is integrated into the flow passage 1a from the primary side opening of the casing 1 as a member. Can be assembled very simply by inserting the bearing 7 into the secondary opening of the casing 2 and fitting the separate bearing 7 into the secondary opening.

  And the integrated flow volume of purified water can be measured by the principle similar to the conventional magnetic sensor type flow sensor by assembling this flow sensor to the water purification path in a water purifier, for example. Moreover, according to the flow rate sensor, since the impeller 2 is pivotally supported by both shafts, the rotation is stabilized as compared with the case of the single shaft. In addition, since the rotating shafts at both ends (the protruding portion 5a of the cap 5 and the shaft rod 6) are integrated with the impeller 2, the impeller 2 does not slide on the rotating shaft in the axial direction, and stable measurement is performed. Is possible. Furthermore, in this embodiment, since the shaft tip of the protruding portion 5a of the cap 5 is sharp, the friction resistance with the shaft hole portion 1b on the secondary side is small, and the impeller 2 rotates even at a small flow rate. Can measure the flow rate. Furthermore, in the above embodiment, as a more preferable example, the flow passages are configured by providing the rectifying blades on the bearings 1b and 7, so that the generation of turbulent flow is prevented. However, it does not exclude that the water passing portions of the bearings 1b and 7 are configured by through holes having an arbitrary shape.

  In the above-described embodiment, one end of the joint 9 is inserted into the secondary side opening of the casing 1 in a watertight manner with an O-ring, and is detachably fixed to the casing 2 with an E-ring 10. Therefore, according to the said structure, disassembly of a flow sensor is also possible by removing the coupling 9, and an internal maintenance can be performed easily. However, the connection structure of the primary side and the secondary side of the casing 1 is an arbitrary configuration. Further, in the above embodiment, the cap 5 forms the integral attachment of the magnet 3 to the impeller 2 and the secondary rotating shaft (protrusion 5 a). However, the magnet 3 is integrated with the impeller 2. If it rotates, it is not limited to the said attachment aspect, Moreover, the cap 5 is abbreviate | omitted and you may comprise the rotating shaft of a secondary side by integrally forming the projection part 5a in the end surface of the impeller 2. FIG. Furthermore, the projections 5a and the shaft tips of the shaft rod 6 are preferably sharp, but they may be spherical and do not exclude uncut forms.

  FIG. 2 shows a second embodiment of the present invention, in which 11 is a casing, 12 is an impeller, 13 is a magnet, and 14 is a box of a magnetic sensor (not shown).

  The casing 11 has a substantially cylindrical shape formed with a linear flow path 11a in which the impeller 12 can be accommodated, and bearings 15 and 16 are arranged on the primary side and the secondary side of the flow path 11a. ing. Each of these bearings 15 and 16 has a wheel shape in which shaft hole portions 15a and 16a are recessed in the center and a plurality of rectifying blades 15b and 16b are provided radially around the shaft hole portions 15a and 16a. It is molded and inserted into the flow path 11a and assembled. And while making it a water flow part between each rectifier blade 15b * 16b, the generation | occurrence | production of a turbulent flow is prevented by making the inner and outer surfaces of the said water flow part parallel, and comprising the same diameter water flow path in this part is doing.

  On the other hand, the impeller 12 is provided with a plurality of blades 12a that spirally convert hydraulic power into rotational force on the outer peripheral surface, and is formed of, for example, synthetic resin. In this embodiment, the magnet 13 is integrally embedded in the primary side (upstream side) end surface of the impeller 12, and a metal shaft rod 17 such as stainless steel is provided in the impeller 12 together with the magnet 13. ing. The shaft rod 17 is inserted through the impeller 12 so that both ends are exposed. The exposed both ends are loosely inserted into the shaft holes 15a and 16a of the bearings 15 and 16 as rotary shafts so as to be pivoted. It rotates integrally with the vehicle 12. The shaft rod 17 may be made of resin. Further, the shaft rod 17 can be penetrated into the impeller 12 by press-fitting or insert molding, but other methods can be adopted as long as both 12 and 17 can be integrated.

  Here, since the impeller 12 is pressed to the secondary side by water pressure, in this embodiment, the shaft hole portion 15a of the bearing 15 on the secondary side is made of metal to improve wear resistance. Further, the secondary shaft tip of the shaft rod 17 corresponding to the metal shaft hole portion 15a is sharpened to reduce the frictional resistance, to increase the wear resistance, and to rotate the impeller 12 with a small flow rate. This is the same as in the first embodiment.

  According to the flow rate sensor having the above-described configuration, the secondary bearing 15 is first fitted into the flow path 11a of the casing 11, and after the impeller 12 with the magnet 13 and the shaft rod 17 provided in advance is inserted, By simply fitting the bearing 16 on the primary side, it can be assembled very easily. In this flow sensor, since one shaft rod 17 penetrates the impeller 12 to constitute the rotating shaft, accurate centering can be performed with a simpler configuration, and one bearing 15 Since the shaft hole portion 15b is made of metal, the wear resistance is excellent. Moreover, since both magnets 13 and 13 are integrated by embedding a part of the magnet 13 in the impeller 12, the configuration is simpler, so that the cap for accommodating the magnet 13 can be omitted, and the overall length is short. Thus, a smaller flow sensor can be obtained.

  In this embodiment as well, as in the first embodiment, one end of the joint 18 is inserted into the secondary opening of the casing 11 in a watertight manner with an O-ring, and is detachably fixed to the casing 2 with an E-ring 19. However, the flow sensor can be disassembled, but the connection structure on the primary side and the secondary side is arbitrary.

Sectional drawing of the flow sensor which concerns on 1st embodiment of this invention. Sectional drawing of the flow sensor which concerns on 2nd embodiment of this invention.

Explanation of symbols

1 · 11 Casing 2 · 12 Impeller 3 · 13 Magnet 1b · 15 Secondary bearing 5a Protrusion (secondary rotary shaft)
6 shaft rod (rotary shaft on the primary side)
7.16 Primary side bearing 17 Shaft bar (Rotating shaft)

Claims (6)

A casing that forms a flow path, and a pair of bearings that have a water flow portion around the shaft hole portion and that are disposed so as to face the shaft hole portion on the primary side and the secondary side of the flow path. An impeller that is positioned between the pair of bearings and is accommodated in the flow path, a magnet that is provided integrally with the impeller, and a magnetic sensor that is provided in a part of the casing and detects rotation of the magnet. And a rotary shaft that integrally projects from both end faces of the impeller, and the rotary shaft pivotally supports the rotary shaft in the shaft hole portion of the bearing , wherein the rotary shaft is a blade It consists of a resin protrusion projecting on one end face of the car and a shaft bar projecting on the opposite end face of the impeller, and the protrusion accommodates the magnet and is attached to the one end face of the impeller The resin cap is integrally molded, and the magnetic cap is formed on the peripheral surface of the resin cap. Flow sensors, characterized in that it has a window for transmitting the magnetic force. The flow sensor according to claim 1 , wherein a shaft hole portion of the bearing pivotally supporting the shaft rod is made of metal. The flow sensor according to claim 1 or 2 , wherein the axis of rotation is sharp or spherical. The flow sensor according to any one of claims 1 to 3 , wherein the shaft rod is made of metal. The flow sensor according to any one of claims 1 to 4 , wherein the bearing is provided with rectifying blades radially from the shaft hole portion. The flow rate sensor according to any one of claims 1 to 5, wherein the flow rate sensor is built in a water purifier so that an integrated flow rate of purified water can be measured.

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