JP6069851B2 - Impeller - Google Patents

Description

  The present invention relates to an impeller used for an impeller-type flow meter that measures a flow rate of a fluid.

  As an apparatus for measuring the flow rate of fluid, an impeller-type flow meter in which an impeller having a plurality of blades is provided in a fluid flow path is known. An impeller-type flow meter is, for example, an impeller in which a magnet is incorporated in a blade (see, for example, Patent Document 1) or an impeller having a magnet resin (a resin material including a magnetic material) at the tip of the blade (for example, a patent) Reference 2). The impeller is rotated by the kinetic energy of the fluid to be measured flowing in the flow path, and is configured to measure the flow rate of the fluid to be measured from the rotational speed of the impeller.

JP 2006-162296 A JP-A-61-213724

  However, it is actually difficult to manufacture an impeller that incorporates the aforementioned magnet at the tip of the blade. A configuration in which the magnet is embedded in the boss portion of the impeller is conceivable. In this case, the sensor probe for detecting the magnet extends to the vicinity of the boss and extends to the center of the fluid flow path. As a result, the fluid flow is disturbed, and the measurable range becomes relatively narrow.

  In addition, it is conceivable that the entire impeller is made of a magnetic resin containing a magnetic material, but in this case, it has a magnetic force even to a part that is not particularly required, and rust and iron powder adhere to that part. Problems arise. Moreover, the toughness of an impeller becomes low and the bending strength of a blade root is insufficient.

  The present invention includes a blade having a tip portion formed of a resin material containing a magnetic material, and joining a tip-side blade portion constituting the tip portion and a proximal-side blade portion to which the tip-side blade portion is connected. An object of the present invention is to provide an impeller with improved strength and easy manufacture.

The present invention is an impeller comprising a boss portion having a rotation center and a blade projecting radially outward from the boss portion, wherein the blade is a proximal blade portion on a proximal end side; A distal end side blade portion extending in the extending direction of the blade from the proximal end blade portion, and the proximal end blade portion is formed mainly of a predetermined resin material, and the distal end side The blade portion is formed including the predetermined resin material and the magnetic material, and the proximal-side blade portion and the distal-side blade portion are any of the proximal-side blade portion and the distal-side blade portion. It has a concavo-convex shape constituted by a convex portion projecting from one side to the other, and a concave portion that is recessed in a shape corresponding to the convex portion and into which the convex portion is fitted and the whole of the convex portion is accommodated. It is related to the impeller that is integrally joined by a joining form other than mechanical joining such as a screw through the joint. That.

Further, the convex portion, protruding in the extending direction of and the vane provided in the proximal-side blade portion, the recess is preferably provided on the distal end side wing portion.

  Moreover, it is preferable that the said convex part is located inward in the cross-sectional direction of the said base end side blade | wing part.

  According to the present invention, a blade having a distal end portion formed of a resin material containing a magnetic material, the distal blade portion constituting the distal portion, and a proximal blade portion to which the distal blade portion is connected, Thus, it is possible to provide an impeller that is easy to manufacture.

It is a whole sectional view of impeller type flow meter 1 provided with impeller 3 concerning this embodiment, (a) is a sectional side view, (b) is a front sectional view. It is a front view which shows the impeller 3 which concerns on this embodiment. It is a side view which shows the impeller 3 which concerns on this embodiment. It is an enlarged front view which shows the 1st blade | wing 60 of the impeller 3 which concerns on this embodiment. It is an enlarged front view which shows the convex part 60E of the base end side blade | wing part 60C of the impeller 3 which concerns on this embodiment. It is an expansion perspective view in the radial direction of the boss | hub part 51 which shows the base end side blade | wing part 60C of the impeller 3 which concerns on this embodiment. It is an enlarged front view which shows the positional relationship of the convex part 60E of the base end side blade | wing part 60C and the parting line P of the impeller 3 which concerns on this embodiment. It is an enlarged front view which shows the positional relationship of the 1st blade | wing 60 and the parting line P of the impeller 3 which concerns on this embodiment. It is a principal part enlarged view which shows the 1st modification of the convex part 60E of the base end side blade | wing part 60C of the impeller 3 which concerns on this embodiment. It is a principal part enlarged view which shows the 2nd modification of the convex part 60E of the base end side blade | wing part 60C of the impeller 3 which concerns on this embodiment.

  The impeller of the present invention will be described below with reference to the drawings. First, an impeller flow meter having an impeller according to an embodiment of the present invention will be described.

  FIG. 1 is a cross-sectional view showing the internal configuration of the impeller-type flow meter according to the present embodiment. As shown in FIG. 1, the impeller flow meter 1 according to the present embodiment includes a housing 2, an impeller 3, and a sensor unit 4.

  The housing 2 is formed in a tubular shape through which a fluid to be measured (water, steam, etc.) can flow. The housing 2 includes an inflow port 20 formed on one side in the axial direction of the housing 2, an outflow port 21 formed on the other side in the axial direction of the housing 2, and a flow path 22 formed in the housing 2. Have.

The inflow port 20 can flow in the fluid to be measured. A supply pipe (not shown) for supplying a fluid to be measured to the impeller flow meter 1 can be connected to a part of the housing 2 where the inlet 20 is formed.
The outlet 21 can discharge the fluid to be measured that has flowed in from the inlet 20. A flow pipe (not shown) capable of circulating the fluid to be measured discharged from the outlet 21 can be connected to a part of the housing 2 where the outlet 21 is formed.

  The flow path 22 makes the inflow port 20 and the outflow port 21 communicate with each other. The fluid to be measured that flows in from the inlet 20 and is discharged to the outlet 21 can flow from the inlet 20 to the outlet 21 through the flow path 22. The flow path 22 includes a first flow path 22 a that communicates with the inlet 20 and a second flow path 22 b that communicates with the outlet 21. The first flow path 22a and the second flow path 22b communicate with each other.

  The housing 2 has a first housing 24 and a second housing 25. The first housing 24 and the second housing 25 are disposed on the same axis X and are detachably connected to each other.

The first housing 24 includes a first main body portion 24a and a first flange portion 24b. The 1st main-body part 24a has the inflow port 20, the 1st flow path 22a, and the sensor attachment part 26 (refer FIG.1 (b)). A magnetic sensor 40 (to be described later) constituting the sensor unit 4 is attached to the sensor attachment unit 26.
Further, as shown in FIG. 1A, a first bearing portion 27 capable of pivotally supporting the impeller 3 is provided inside the first main body portion 24a. The 1st bearing part 27 is provided on the axis line X of the housing 2 so that the axis line of the boss | hub shaft part 5 of the impeller 3 mentioned later and the axis line of the housing 2 may correspond. A radial bearing 27 a and a thrust bearing 27 b that pivotally support the impeller 3 are attached to the first bearing portion 27.

  The second housing 25 has a second main body portion 25a and a second flange portion 25b. The 2nd main-body part 25a has the 2nd flow path 22b and the outflow port 21 connected to a 2nd flow path. Moreover, as shown in FIG. 1, the 2nd bearing part 28 which can support the impeller 3 is provided in the inside of the 2nd main-body part 25a. The second bearing portion 28 is provided on the axis X of the housing 2 so that the axis of the boss shaft 5 of the impeller 3 and the axis of the housing 2 coincide with each other. A radial bearing 28 a and a thrust bearing 28 b that support the impeller 3 are attached to the second bearing portion 28.

  The second flange portion 25 b can be connected to the first flange portion 24 b of the first housing 24. The second flange portion 25 b is connected to the first flange portion 24 b by the screw member 8 through the O-ring 7.

  The impeller 3 includes a boss shaft portion 5 and a plurality of blade portions 6. The boss shaft portion 5 is formed in a substantially cylindrical shape. The boss shaft 5 is rotatably supported by the first housing 24 and the second housing 25 at both ends in the axial direction. The plurality of blade portions 6 are provided on the outer peripheral surface 52 of the boss shaft portion 5 at equal intervals. As shown in FIG. 3, the plurality of blade portions 6 have an upstream side surface 6a and a downstream side surface 6b opposite to the upstream side surface 6a. The impeller 3 is formed to rotate when the upstream side surface 6 a of the plurality of blade portions 6 is pushed by the fluid to be measured flowing through the flow path 22 of the housing 2. Some of the plurality of blade portions 6 are magnetized. The configuration of the impeller 3 will be described in detail later.

  The sensor unit 4 includes a magnetic sensor 40 and a display (not shown). The magnetic sensor 40 detects the rotation of the impeller 3. The magnetic sensor 40 detects a change in the magnetic field of the plurality of blade portions 6 of the magnetized impeller 3 as the impeller 3 rotates. In other words, the magnetic sensor 40 detects the rotation of the impeller 3 by a change in the magnetic field. The magnetic sensor 40 is mounted inside the housing 2 at a sensor mounting portion 26 formed in the first main body portion 24a. The magnetic sensor 40 is held by the sensor holder 41 in a state of being mounted inside the housing 2. The sensor holder 41 is attached to the sensor attachment portion 26 formed in the first main body portion 24a. The sensor holder 41 is attached to the sensor attachment portion 26 by a screw member (not shown).

  The display includes a control unit (not shown), a display unit (not shown), and a storage unit (not shown). The control unit calculates the flow rate of the fluid to be measured flowing through the flow path 22 of the housing 2 by the rotation of the impeller 3 detected by the magnetic sensor 40. The display unit displays the flow rate of the fluid to be measured calculated by the control unit. The display unit is provided in the storage unit. The accommodating part accommodates the control part. The accommodating portion accommodates a part of the magnetic sensor 40 held by the sensor holder 41. The accommodating portion can be attached to the sensor attachment portion 26. The accommodating portion is attached to the sensor attachment portion 26 via the sensor holder 41.

  Next, the impeller 3 according to the present embodiment will be specifically described. FIG. 2 is a front view showing the appearance of the impeller 3 according to the present embodiment. FIG. 3 is a side view of the impeller 3 according to the present embodiment as viewed from the side. FIG. 4 is an enlarged view of a main part when the blade part 6 of the impeller 3 according to the present embodiment is viewed from the front side. FIG. 5 is an enlarged view of a main part when a base end side blade portion 60C described later of the impeller 3 according to the present embodiment is viewed from the front side.

  The boss shaft portion 5 of the impeller 3 has a shaft portion 50 and a boss portion 51. The shaft portion 50 is in the shape of an elongated round bar, and constitutes the rotation axis of the impeller 3. The shaft portion 50 is pivotally supported by the radial bearing 27a and the thrust bearing 27b of the first bearing portion 27 shown in FIG. 1, and the radial bearing 28a and the thrust bearing 28b of the second bearing portion 28 shown in FIG. Thus, the shaft portion 50 can rotate around the axis X in the housing 2.

  The boss portion 51 is formed in a substantially cylindrical shape. The shaft portion 50 passes through the axial center position of the boss portion 51, and the boss portion 51 is supported by the shaft portion 50. That is, the shaft portion 50 forms the rotation center of the boss portion 51.

  As shown in FIG. 2, each of the plurality of blade portions 6 includes a first blade 60, a second blade 61, a third blade 62, and a fourth blade 63 that protrude outward in the radial direction of the boss portion 51. The fifth blade 64, the sixth blade 65, the seventh blade 66, and the eighth blade 67 are included. That is, the several blade | wing part 6 which concerns on this embodiment is comprised from eight blade | wings. As shown in FIG. 3, the first blade 60, the second blade 61,..., The eighth blade 67 are in a state where they are inclined so as to have a predetermined angle with respect to the axis X of the boss shaft portion 5. It is provided on the outer peripheral surface 52 of the shaft portion 5.

  As an inclination angle with respect to the axis X of the first blade 60, the second blade 61, ..., the eighth blade 67, 9 to 30 degrees can be exemplified. In the present embodiment, the first blade 60, the second blade 61,..., The eighth blade 67 are formed so that the inclination angle with respect to the axis X is 20 degrees. The inclination angle of the first blade 60, the second blade 61,..., The eighth blade 67 with respect to the axis X is the first blade 60, the second blade 61, and the like in the direction from the upstream side to the downstream side. ..., the angle between the direction Y (see FIG. 3) from the upstream end to the downstream end of the eighth blade 67 and the plane including the axis X is defined.

  2, each of the first blade 60, the second blade 61,..., The eighth blade 67 is in the circumferential direction of the boss shaft portion 5 (hereinafter referred to as “circumferential direction”). It arrange | positions at the outer peripheral surface 52 of the boss | hub part 51 so that it may become equal intervals (45 degree intervals).

  Next, the structure of the 1st blade | wing 60, the 2nd blade | wing 61, ..., the 8th blade | wing 67 is demonstrated. In addition, the 1st blade | wing 60, the 2nd blade | wing 61, ..., the 8th blade | wing 67 is formed in the same shape, and has the same structure. For this reason, it demonstrates using the 1st blade | wing 60 and the description about the 2nd blade | wing 61, the 3rd blade | wing 62, ..., the 8th blade | wing 67 is abbreviate | omitted.

  The thickness of the 1st blade | wing 60 becomes thick rapidly as it goes to the downstream from the upstream of a fluid. Specifically, in FIG. 3, the fluid flows from the left side to the right side. In the direction from the upstream side to the downstream side of the fluid, the first blade 60 reaches from the upstream end of the first blade 60 to a portion that is about ½ of the length of the first blade 60 in the same direction. One blade 60 has an upstream-side thickness portion 60A including the maximum thickness portion where the thickness is the largest. Moreover, it has the part 60B which becomes thin gradually from the upstream thickness part 60A along the direction which goes to the downstream from the upstream of a fluid.

Moreover, as shown in FIG. 4, the 1st blade | wing 60 has the base end side blade | wing part 60C and the front end side blade | wing part 60D. The base end side blade portion 60 </ b> C is a portion on the base end portion side of the first blade 60. The base end blade portion 60C is integrally formed with the boss portion 51, and is preferably formed mainly of a resin material such as PPS (polyphenylene sulfide), EEA (ethylene ethyl acrylate copolymer), nylon, or the like. In this embodiment, it is formed of PPS (polyphenylene sulfide) which is a reinforced plastic.
“To be formed mainly of a resin material” includes not only the case of being formed of only a resin material but also the case of including a material other than the resin material (such as a metal material) within a range not impeding the function of the impeller.
The length of the base end side blade portion 60 </ b> C is preferably 60% to 90% of the length in the longitudinal direction of the first blade 60. In the present embodiment, the base end side blade portion 60 </ b> C is 2/3 of the length in the longitudinal direction of the first blade 60.

  The distal-side blade portion 60D is integrally joined to the proximal-side blade portion 60C by two-stage molding by insert molding, as will be described later, instead of being joined by an adhesive or the like, and is firmly fixed to the proximal-side blade portion 60C. ing. Therefore, in practice, the distal-side blade portion 60D does not come off from the proximal-side blade portion 60C, but only the proximal-side blade portion 60C is illustrated as shown in FIGS. FIG. 6 is an enlarged perspective view in the radial direction of the boss portion 51 showing the base end side blade portion 60C of the impeller 3 according to the present embodiment.

As shown in FIGS. 5 and 6, the proximal end blade portion 60 </ b> C includes a convex portion 60 </ b> E that forms a convex portion of the joint portion having an uneven shape on the distal end portion side. The convex portion 60E has a rectangular parallelepiped shape, and protrudes outward in the radial direction of the boss portion 51 (in the extending direction of the first blade 60) from the end surface 60F of the distal end portion of the proximal end blade portion 60C.
The convex portion 60E is the center in the width direction of the end surface 60F of the distal end portion of the proximal end blade portion 60C, and is near the upstream end portion of the first blade 60 in the direction from the upstream side to the downstream side of the fluid. To the substantially central position of the first blade 60 in the same direction. That is, the convex portion 60E is mainly a portion of the upstream-side thickness portion 60A, is located inward in the cross-sectional direction of the proximal-side blade portion 60C, and does not protrude from the side surface of the proximal-side blade portion 60C. . In other words, the convex portion 60E is positioned inward in the transverse cross-sectional direction of the proximal end blade portion 60C.

  The height of the convex portion 60E in the projecting direction of the convex portion 60E, and the height from the end surface 60F (see FIG. 5) of the distal end portion of the proximal end side blade portion 60C is the proximal end of the distal end side blade portion 60D described later. It is preferably 5% to 20% of the height from the side end face 60G to the tip of the tip side blade portion 60D. In the present embodiment, the height of the convex portion 60E is about 1/10 of the height from a base end side end surface 60G (described later) of the distal end side blade portion 60D to the distal end of the distal end side blade portion 60D.

  The distal blade portion 60D is a portion on the distal portion side of the first blade 60, and extends from the proximal blade portion 60C in the extending direction of the first blade 60. For example, the front end blade portion 60D may be formed of a resin material such as PPS (polyphenylene sulfide), EEA (ethylene ethyl acrylate copolymer), nylon, or the like, and a magnetic material such as ferrite, neodymium, or samarium cobalt. preferable. In the present embodiment, the tip blade portion 60D is made of a plastic magnet in which magnetized iron powder made of a ferrite-based isotropic bonded magnet is contained in PPS (polyphenylene sulfide). The length of the tip side blade portion 60D is preferably 10% to 40% of the length of the first blade 60 in the longitudinal direction. In the present embodiment, the tip blade portion 60D is 1/3 of the length of the first blade 60 in the extending direction.

  As shown in FIG. 4, a part of the distal end side blade portion 60D that is opposed to the end surface 60F of the distal end portion of the proximal end side blade portion 60C is the most radially inward of the boss portion 51 in the distal end side blade portion 60D. The base end side end surface 60G located in the direction is provided. A recess 60H is formed in the proximal end surface 60G. The concave portion 60H is provided in the tip side blade portion 60D and has a concave shape corresponding to the convex portion 60E. That is, the concave portion 60H constitutes a joint portion with the convex portion 60E, the end surface 60F, and the base end side end surface 60G, and is concave in a shape corresponding to the convex portion 60E. A convex portion 60E is fitted in the concave portion 60H.

  The proximal-side blade portion 60C and the distal-side blade portion 60D are integrally joined through joint portions (convex portions 60E, concave portions 60H, end surfaces 60F, proximal-side end surfaces 60G) having an uneven shape. “Integrally joined” means that the base-side blade portion 60C and the distal-side blade portion 60D are integrally joined by multistage molding (such as two-stage molding) or adhesion between resin materials. Means that it does not include a form bonded by mechanical bonding such as screws.

  Next, the manufacturing method of the 1st blade | wing 60 of the impeller 3, the 2nd blade | wing 61, ..., the 8th blade | wing 67 is demonstrated. In addition, the 1st blade | wing 60, the 2nd blade | wing 61, ..., the 8th blade | wing 67 is manufactured by the same process. For this reason, only the manufacturing process of the 1st blade | wing 60 is demonstrated and the description about the 2nd blade | wing 61, the 3rd blade | wing 62, ..., the 8th blade | wing 67 is abbreviate | omitted.

  The first blade 60 is formed by performing two-stage molding by insert molding on the proximal end blade portion 60C and integrating the distal end blade portion 60D with the proximal end blade portion 60C. FIG. 7 is an enlarged front view showing the positional relationship between the convex part 60E of the base end side blade part 60C and the parting line P of the impeller 3 according to the present embodiment. FIG. 8 is an enlarged front view showing the positional relationship between the first blade 60 and the parting line P of the impeller 3 according to the present embodiment.

  Specifically, the base end side blade portion 60C integrally formed with the boss portion 51 is inserted into the mold, and the end surface 60F and the convex portion 60E of the tip end portion of the base end side blade portion 60C are disposed in the cavity of the mold. As described above, the base end side blade portion 60C is set in a mold. At this time, the parting line P that is a dividing surface between the fixed mold and the movable mold of the mold has a positional relationship as shown by a two-dot chain line in FIG. In FIG. 7, the left side of the two-dot chain line is the movable type side, and the right side of the two-dot chain line is the fixed mold side. The same applies to FIG. 8 described later.

  Next, by filling the cavity of the mold with a melted plastic magnet, the convex portion 60E of the proximal end blade portion 60C and the end face 60F of the distal end portion of the proximal end blade portion 60C are covered with the plastic magnet. Next, the plastic magnet in the mold cavity is cooled and solidified, the mold is opened, and the proximal end blade portion 60C and the boss portion 51 are taken out. Thereby, formation of the front end side blade | wing part 60D integrally joined to the base end side wing | blade part 60C is completed.

  In the first blade 60 in which the tip blade portion 60D is formed, the parting line P has a positional relationship as shown by a two-dot chain line in FIG. Further, when only the base end side blade portion 60C is viewed, the parting line P has a positional relationship as shown by a two-dot chain line in FIGS.

  According to the impeller 3 of the embodiment of the present invention having the above-described configuration, the first blade 60 includes a base end side blade portion 60C on the base end portion side and the first blade 60 extends from the base end side blade portion 60C. The proximal end blade portion 60C is made of PPS (polyphenylene sulfide) which is a reinforced plastic. Therefore, the strength of the base end side blade portion 60 </ b> C that is a portion on the base portion side of the first blade 60 can be increased.

  Further, since the tip blade portion 60D is formed to include a resin material and a magnetic material, the tip blade portion 60D, which is a portion necessary for detecting the rotation of the impeller 3, has a magnetic material only. Can be realized. For this reason, it can suppress as much as possible that rust and iron powder adhere to the 1st blade | wing 60. FIG.

  Moreover, the base end side blade | wing part 60C and the front end side blade | wing part 60D are integrally joined via the junction part which has predetermined | prescribed uneven | corrugated shape. More specifically, the joint portion is provided on the proximal end blade portion 60C and protrudes in the extending direction of the blade, and a concave shape provided on the distal end blade portion 60D and corresponding to the protrusion 60E. And a recess 60H. Therefore, it is easy to manufacture, and it is possible to increase the bonding area between the base-side blade portion 60C and the tip-side blade portion 60D, and to increase the bonding strength.

Moreover, since the convex part 60E is located inward in the cross-sectional direction of the base end side blade | wing part 60C, all four side surfaces of the convex part 60E are joined to the front end side blade | wing part 60D. For this reason, a large bonding area can be secured and the bonding strength can be increased.
The second blades 61,..., The eighth blade 67 also exhibit these effects described above.

  The embodiment of the present invention is not limited to the above embodiment, and can be modified within the technical scope described in the claims. For example, the shape of the convex portion is not limited to a rectangular parallelepiped shape like the convex portion 60E in the present embodiment. FIG. 9 is an essential part enlarged view showing a first modification of the convex portion 160E of the base end side blade portion 60C of the impeller 3 according to the present embodiment. FIG. 10 is an essential part enlarged view showing a second modification of the convex portion 260E of the base end side blade portion 60C of the impeller 3 according to the present embodiment.

As shown in FIG. 9, the protruding end of the convex portion 160 </ b> E may have a wave shape having irregularities when viewed from the side. Further, as shown in FIG. 10, the protruding end of the convex portion 260E may have a so-called jagged shape having a plurality of convex corners and concave corners in a side view.
Further, the joint portion may have a shape having irregularities in the thickness direction of the first blade 60, the second blade 61,. Thus, by having an uneven | corrugated shape, the joining area of 60 C of base end side blade | wing parts and 60B of front end side blade | wing parts can be enlarged further, and joining strength can be raised further.
In the present embodiment, the proximal-side blade portion 60C has the convex portion 60E and the distal-end blade portion 60D has the concave portion 60H. However, the present invention is not limited to this. The proximal end blade portion 60C may have a concave portion, and the distal end side blade portion 60D may have a convex portion.

  Moreover, in this embodiment, although the several blade | wing part 6 was comprised from 8 blade | wings, in this invention, it is not limited to this. For example, the plurality of blade portions may be any one having two or more blades. Further, the outer shape of the blade is not limited to the outer shape of the first blade 60, the second blade 61,.

  Further, as the fluid to be measured to be circulated through the impeller flow meter 1, for example, air, gas, oil, or the like can be used in addition to steam or liquid water. That is, the impeller type flow meter 1 according to the present embodiment may circulate gas or circulate liquid.

  Moreover, in this embodiment, although the impeller 3 was used for the impeller-type flow meter 1, it is not limited to this. For example, the impeller may be used in a pump or the like that generates a fluid flow by actively rotating the impeller.

3 impeller 5 boss shaft portion 6 blade portion 51 boss portion 60 first blade 60C proximal side blade portion 60D distal end side blade portion 60E convex portion 60H concave portion

Claims (3)

An impeller comprising a boss portion having a rotation center and a blade projecting radially outward from the boss portion,
The blade includes a proximal-side blade portion on the proximal end side, and a distal-side blade portion on the distal end side extending in the extending direction of the blade from the proximal-side blade portion,
The base end side blade portion is formed mainly of a predetermined resin material,
The tip side blade portion is formed including the predetermined resin material and magnetic material,
The proximal-side blade portion and the distal-side blade portion are a convex portion that protrudes from one of the proximal-side blade portion and the distal-side blade portion toward the other, and a shape corresponding to the convex portion. And a concave portion in which the convex portion is fitted and the whole convex portion is accommodated, and a joint portion having a concave-convex shape formed by a joint form other than mechanical coupling such as a screw. Impeller joined to The convex portion is provided on the proximal side wing portion and protrudes in the extending direction of the blade,
The recess, the impeller of claim 1 which is provided on the distal end side wing portion.   The impeller according to claim 2, wherein the convex portion is positioned inward in a cross-sectional direction of the proximal end blade portion.

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