JP7215969B2 - Centrifugal impeller and centrifugal impeller manufacturing method - Google Patents

Description

The present invention comprises a circular main plate having an insertion hole in the center through which a support shaft is inserted; A hub protruding to one side in the axial direction of the insertion hole, and a position where a twisted portion that is twisted up is provided at the end portion on the hub side so as to avoid overlapping with each other when viewed from the axial direction of the insertion hole. and a centrifugal impeller provided with a plurality of blade portions projecting from the circular main plate and the hub to one side in the axial direction, and a method for manufacturing the centrifugal impeller.

Patent Document 1 discloses a centrifugal fan that is divided into two parts in the axial direction, that is, an inlet part and an outlet part made of resin, each of which is formed so as to be capable of being cut out from a mold in the axial direction. Patent Document 2 discloses a blade configured by a hub-side blade that is integrally formed with the shroud and a shroud-side blade that is integrally formed with the shroud.

JP-A-59-018296 Japanese Patent No. 5269025

In the case disclosed in Patent Document 1, the inlet portion and the outlet portion are each thickened in the axial direction, resulting in an increase in axial size of the centrifugal impeller. Moreover, the blades of the inlet part are in a state of floating in the air, and the rigidity of the resin-made blades tends to become weak, and vibration and noise are likely to occur.

In addition, in the technique disclosed in Patent Document 2, in order to prevent undercuts from occurring when twisting the hub-side blades integrally formed with the hub in order to increase the efficiency of sending out the fluid by the blades, A complex mold having slide cores, curved cores, drawing cores, etc. is required, resulting in increased costs.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a centrifugal impeller that has a highly efficient three-dimensional shape and can be efficiently manufactured at low cost.

In order to achieve the above object, the present invention provides a circular main plate having an insertion hole in the center through which a support shaft is inserted, and a cylindrical main plate having a substantially frustoconical outer surface and continuing coaxially with the insertion hole. A hub projecting from the circular main plate to one side in the axial direction of the insertion hole, and a twisted portion that is twisted up at the end on the hub side and viewed from the axial direction of the insertion hole. A centrifugal impeller comprising the circular main plate and a plurality of blades protruding from the hub to one side in the axial direction at positions avoiding mutual overlap, wherein the circular main plate, the hub and the blades are made of resin. The impeller main body is provided with a cutout hole having a shape including the projection of the blade portion in the axial direction of the insertion hole. and an interpolating member made of resin having an interpolating portion smoothly connected to the surface of the blade portion is brought into contact with the impeller main body from the other side of the insertion hole in the axial direction, and the interpolating member is attached to the plurality of blade portions. A front plate made of resin abuts from the opposite side, and cutout portions are formed in the circular main plate and the plurality of blade portions and are arranged near the outer circumference of the circular main plate and open to the outer circumference of the circular main plate, A plurality of welding bosses projecting toward the front plate while filling the cutouts are provided integrally with the interpolating member while having an outer end surface continuous with the outer circumference of the interpolating member. A first feature is that a plurality of recesses into which the tip portions are loosely fitted are formed in the front plate, and the tip portions of the welding bosses are welded to the recesses.

Further, in addition to the configuration of the first characteristic, the present invention includes a welding surface to which the tip of the welding boss is welded to the closed end of the recess, and both sides of the welding surface in the circumferential direction of the front plate. A second feature is that an escape groove arranged in the groove is formed .

In the present invention, in addition to the configuration of the second characteristic, the end portion of the relief groove on the outer peripheral side of the front plate is set at a position spaced inwardly from the outer periphery of the front plate . 3.

The present invention is a centrifugal impeller manufacturing method for manufacturing the centrifugal impeller according to claim 1, wherein a tip end of the weld boss portion is spaced inwardly from the outer end surface of the weld boss portion. A fourth feature is that a protrusion having a triangular vertical cross-section is integrally provided with the welding boss before the welding boss is welded to the recess .

In addition to the configuration of the fourth characteristic, the present invention has a welding surface for welding at least the projection to the closed end of the recess before the projection is welded, and a welding surface for welding the projection in the circumferential direction of the front plate. A fifth feature is that escape grooves are formed on both sides of the welding surface .

In addition to the configuration of the fifth feature, the sixth aspect of the present invention is that the end of the escape groove on the outer peripheral side of the front plate is set at a position spaced inwardly from the outer periphery of the front plate. characterized by

Further, the present invention provides a centrifugal impeller manufacturing method for manufacturing a centrifugal impeller having the first characteristic, wherein the impeller main body having the notch, the front plate having the recess, and the front end portion are longitudinally cut. injection molding each of said interpolation members having said welding boss provided with a projection having a triangular surface ; and loosely fitting said welding boss into said recess to close said projection with said recess. a step of heating and melting at least the protrusions in a state in which the impeller main body, the front plate, and the interpolating member are superimposed while abutting on the end portions thereof to weld the welding boss portions to the recesses; A seventh feature is to execute.

According to the first feature of the present invention, a cut-out hole having a shape including the projection of the blade is formed in the impeller body made of resin integrally including the circular main plate, the hub, and the blade, so that the blade can be twisted. It is possible to avoid an undercut shape during resin molding even with a three-dimensional shape having an edge portion, and the cutout hole is filled with the interpolation portion of the resin-made interpolation member. A thin centrifugal impeller having efficient three-dimensional blades can be manufactured at low cost. In addition, a mold device for molding such a centrifugal impeller does not require slide cores, curved cores, drawing cores, etc., and a movable mechanism for moving them, so that the manufacturing cost can be significantly reduced. In addition, by eliminating the need for a moving mechanism, it is possible to create multiple cavities in the extra space, using a so-called "multi-cavity resin molding die" to produce a large amount of centrifugal impeller parts at once. Therefore, a three-dimensional centrifugal impeller can be manufactured at low cost. A plurality of welding bosses projecting from the interpolating member are formed on the front plate while filling notches formed on the plurality of blades of the impeller body and the circular main plate and opening to the outer periphery of the circular main plate. Since the interpolating member is welded to the concave portion, the interpolating member is connected and fixed to the impeller main body and the front plate all at once, thereby making it possible to easily manufacture a three-dimensional centrifugal impeller. In addition, the welding boss part is welded in a state of being loosely fitted in the recess of the front plate at a position closer to the outer periphery of the front plate, thereby improving the gas release property at the time of welding and preventing the occurrence of welding failure. be able to.

According to the second and fifth characteristics of the present invention, the closed end of the concave portion is formed with a welding surface and escape grooves on both sides of the welding surface, so that the gas generated during welding can be removed from the outer periphery of the front plate. It is possible to prevent the melted resin from leaking to the side and to prevent the resin melted at the time of welding from protruding to the outer periphery of the centrifugal impeller, thereby eliminating the need for deburring finish.

According to the third and sixth characteristics of the present invention, since the relief groove does not open to the outer periphery of the front plate, the gas generated when the resin melts escapes from the relief groove to the outer periphery of the front plate for welding. To perform burr-removing finishing by more reliably preventing the melted resin from protruding to the outer peripheral side of a centrifugal impeller during welding by accumulating the melted resin on the escape groove side while preventing the occurrence of defects. can be made unnecessary.

According to a fourth feature of the present invention, a protrusion having a triangular vertical cross section is integrally formed at the tip of the welding boss before welding to the recess of the welding boss. is spaced inwardly from the outer end surface of the welding boss, the melted resin protrudes to the outer peripheral side of the centrifugal impeller while making it easier to melt the protrusion at the tip of the welding boss during welding. This makes it unnecessary to perform deburring finishing such as shot blasting after the welding process.

Furthermore, according to the seventh feature of the present invention, the impeller main body, the front plate and the interpolating member are injection molded, respectively, and then the impeller main body and the front plate are formed while the welding bosses are loosely fitted into the recesses of the front plate. and the interpolating member are overlapped and the tip of the welding boss portion is welded to the concave portion by heating and melting, thereby preventing the melted resin from flowing out to the outer periphery of the centrifugal impeller while preventing the interpolating member and the impeller main body. and the front plate can be connected and fixed at once, thereby simplifying the manufacturing process and making it possible to manufacture a thin centrifugal impeller having highly efficient three-dimensional blades at low cost. .

1 is a partially cutaway perspective view of an electric fluid pump; FIG. It is a perspective view of a centrifugal impeller. It is an exploded perspective view of a centrifugal impeller. It is a perspective view near the recessed part of a front plate. FIG. 3 is a cross-sectional view taken along line 5-5 of FIG. 2;

An embodiment of the present invention will be described with reference to the attached FIGS. 1 to 5. First, in FIG. A shaft 8, a rotor 10 rotatably supported by the support shaft 8, a centrifugal impeller 9 fixed to the rotor 10 and housed in the pump chamber 6, and surrounding the rotor 10 outside the casing 7. and a stator 11 for

The casing 7 includes a suction cylinder portion 13b extending vertically while forming a suction port 12 opening at the upper end of the central portion of the pump chamber 6, and a discharge cylinder portion extending tangentially to the outer peripheral portion of the pump chamber 6. 13 c and a can-shaped case member 14 coupled to the pump case 13 , and the pump chamber 6 is formed between the case member 14 and the pump case 13 .

The pump case 13 includes a dish-shaped pump case main portion 13a that is open downward, the suction cylinder portion 13b that is connected to the center of the upper end of the pump case main portion 13a, and the pump case 13 that is connected to the outer periphery of the pump case 13. and a first flange portion 13d projecting radially outward from the lower end of the pump case main portion 13a. is stepped such that its radially outer side is closer to the case member 14 side than its inner side.

The case member 14 includes a bottomed cylindrical portion 14a having an inner diameter smaller than the inner diameter of the pump case main portion 13a and having an open top, and a bottomed cylindrical portion 14a projecting radially outward from the upper end portion of the bottomed cylindrical portion 14a. It is formed of synthetic resin integrally with a second flange portion 14b that abuts and fits into the first flange portion 13d from below.

An intermediate case member 15 and a cover member 16 sandwiching the intermediate case member 15 and the casing 7 are coupled to the casing 7 . The intermediate case member 15 includes a cylindrical case member main portion 15a that coaxially surrounds the bottomed cylindrical portion 14a, and the case member main portion 15a.
5a and a fourth flange portion 15c projecting radially outward from the lower portion of the case member main portion 15a. The upper portion of the member main portion 15a and the third flange portion 15b are fitted to the second flange portion 14b by bringing the third flange portion 15b into contact with the second flange portion 14b from below, The first flange portion 13d and the third flange portion 15b are joined with the second flange portion 14b interposed therebetween.

The cover member 16 includes a cover member main portion 16a formed in a bottomed tubular shape with a closed lower end portion, and a lower end of the intermediate case member 15 projecting radially outward from the upper end portion of the cover member main portion 16a. A fifth flange portion 16b coupled from below to the fourth flange portion 15c of the portion is integrally provided, and an annular seal is provided between the fourth flange portion 15c and the fifth flange portion 16b. A member 17 is clamped.

The stator 11 is fixed to the outer surface of the bottomed cylindrical portion 14 a of the case member 14 , and the stator 11 is surrounded by the case member main portion 15 a of the intermediate case member 15 . A control circuit board 18 is accommodated and fixed in the cover member main portion 16 a of the cover member 16 .

One end portion of the support shaft 8 at the uppermost position is held by a holding portion 20 provided in the pump case 13 of the casing 7 and arranged inside the suction port 12 .

The holding portion 20 has a fitting recess 21 that opens downward, and is disposed in the central portion of the end portion of the suction cylinder portion 13b on the pump chamber 6 side. It is integrally connected to the inner circumference of the pump chamber 6 side end portion of the suction cylinder portion 13b via a plurality of support arm portions 22 arranged at intervals in the circumferential direction. Further, the case member 14 integrally has a cylindrical support cylinder portion 14c extending upward from the bottom closed portion of the bottomed cylinder portion 14a, and the one end portion of the support shaft 8 is the fitting recess 21. , and the other end of the support shaft 8 is fitted into the support cylinder portion 14c.

The rotor 10 comprises a rotor hub 24 and bond magnets 25 fixed to the rotor hub 24 . The rotor hub 24 includes a cylindrical magnet support portion 24a that coaxially surrounds the support cylinder portion 14c, and a magnet support portion 24a that is smaller in diameter than the magnet support portion 24a and coaxially surrounds the support shaft 8. An extension cylinder portion 24b extending upward from the upper end portion of the magnet 24a is coaxially and integrally connected to the extension cylinder portion 24b. The centrifugal impeller 9 is fixed to the upper portion of the portion 24b by snap fitting or the like.

The rotor 10 and the centrifugal impeller 9 fixed to the extended cylindrical portion 24b of the rotor hub 24 thereof are rotatable on the support shaft 8 via first and second slide bearings 30 and 31. supported by

The first slide bearing 30 is press-fitted to the upper portion of the extended cylindrical portion 24b with a washer 28 interposed between the first sliding bearing 30 and the holding portion 20. As shown in FIG. Further, the second slide bearing 31 is press-fitted into the lower portion of the extended cylindrical portion 24b with a gap in the axial direction from the first slide bearing 30. As shown in FIG.

Also referring to FIG. 2, the centrifugal impeller 9 is formed by joining an impeller body 35 to an interpolating member 36 and a front plate 37 sandwiching the impeller body 35 from both sides of the support shaft 8 in the axial direction. The impeller main body 35, the interpolating member 36 and the front plate 37 are each made of resin, for example, polyphenylene sulfide (PPS) resin mixed with glass fiber.

Also referring to FIG. 3, the impeller main body 35 includes a circular main plate 39 having an insertion hole 38 in the central portion through which the support shaft 8 and the extension cylindrical portion 24b of the rotor 10 are inserted, and a substantially truncated main plate 39. It is formed in a tubular shape coaxially connected to the insertion hole 38 while having a frusto-conical outer surface, and protrudes from the circular main plate 39 to one axial side of the insertion hole 38 (upward when assembled to the electric fluid pump). It has a hub 40 and a twisted portion 41a at the end on the hub 40 side, which is twisted up in the direction of rotation of the rotor 10 (clockwise when viewed from above the rotor 10 in this embodiment). While viewed from the axial direction of the insertion hole 38, the circular main plate 39 and a plurality of (for example, five) blade portions 41 protruding from the hub 40 to one side in the axial direction are integrally formed at positions avoiding overlapping with each other. have.

Further, in the impeller main body 35, a cutout hole 42 having a shape including projection of the blade portion 41 onto the circular main plate 39 and the hub 40 in the axial direction of the insertion hole 38 is provided to the blade portion 41 individually. Correspondingly formed.

The interpolating member 36 has an interpolating portion 44 that fills the cutout hole 42 of the impeller main body 35 and smoothly continues to the surfaces of the circular main plate 39, the hub 40 and the blade portion 41. A circular auxiliary plate 43 abutting on the insertion hole 38 from the other axial direction side of the insertion hole 38 and the interpolating portion 44 protruding from the circular auxiliary plate 43 are integrally provided. formed to have the same diameter as

Further, the interpolating section 44 includes a main plate interpolation portion 44a that fills a portion of the cutout hole 42 corresponding to the circular main plate 39, and a hub interpolation portion 44b that fills a portion of the cutout hole 42 corresponding to the hub 40. have.

The front plate 37 abuts on the portion of the impeller main body 35 excluding the twisted portions 41a of the plurality of blades 41 from the side opposite to the interpolating member 36. The annular plate portion 45, A short cylindrical portion 46 is formed integrally with the inner periphery of the annular plate portion 45 and projects slightly toward the opposite side of the impeller main body 35 . Between the short cylindrical portion 46 and the projecting portion from the hub 40 and the hub 40 of the extending cylindrical portion 24b inserted through the hub 40 of the impeller main body 35, the An annular inlet 47 (see FIG. 1) leading to the inlet 12 is formed.

The circular main plate 39 and the plurality of blade portions 41 of the impeller main body 35 are provided with cutout portions 50 that are arranged near the outer circumference of the circular main plate 39 and open to the outer circumference of the circular main plate 39. A plurality of welding bosses 51 protruding toward the front plate 37 while filling the notches 50 are integrally provided on the circular auxiliary plate 43 of the member 36 so as to enable welding to the front plate 37. be. These welding boss portions 51 have an outer end surface 51a that is flush with the outer circumference of the interpolating member 36, that is, the outer circumference of the circular auxiliary plate 43, and in a state in which the notch portion 50 is filled, the blade portion 41 is smooth. It is formed in a curved shape that continues to the

A protrusion 52 is formed integrally with the tip portion of the welding boss portion 51 at a position spaced inward from the outer end surface 51a of the welding boss portion 51. The protrusion 52 projects from the welding boss. The portion 51 has a triangular vertical cross-sectional shape before being welded to the front plate 37 and protrudes from the tip portion of the welding boss portion 51 .

On the other hand, as clearly shown in FIG. 4, the annular plate portion 45 of the front plate 37 has a plurality of (five in this embodiment) concave portions 53 into which the tip portions of the welding boss portions 51 are loosely fitted. is formed, and the tip of the welding boss portion 51 is welded to the concave portion 53 as shown in FIG.

At the closed end of the recess 53 before the projection 52 is welded, at least welding surfaces 54 for welding the projection 52 are arranged on both sides of the welding surface 54 in the circumferential direction of the front plate 37. An end of the escape groove 55 on the outer peripheral side of the front plate 37 is set at a position spaced inwardly from the outer periphery of the front plate 37 .

By the way, when the welding boss portion 51 is welded to the concave portion 53, the protrusion 52 having a triangular vertical cross section is heated and melted from the apex portion thereof and is pressed against the welding surface 54. is melted with the welding surface 54 and rolled out to be integrated with the annular plate portion 45 of the front plate 37 .

Moreover, when the interpolating member 44 is injection-molded with the resin injection position of the mold positioned at the protrusion 52, and the resin forming the interpolating member 44 is PPS resin containing glass fibers. In addition, the glass fiber content in the projections 52 can be reduced to make the projections 52 easier to melt and to facilitate welding.

In manufacturing such a centrifugal impeller 9, the impeller main body 35 having the notch 50, the front plate 37 having the recess 53, and the welding boss provided with the protrusion 52 at the tip end thereof After the step of injection molding each of the interpolating members 36 having the portion 51, the welding boss portion 51 is loosely fitted into the recess 53, and the protrusion 52 is brought into contact with the closed end portion of the recess 53. With the impeller main body 35 , the front plate 37 and the interpolating member 36 superimposed, at least the protrusions 52 are heated and melted to weld the weld bosses 51 to the recesses 53 .

Next, the operation of this embodiment will be described. A circular main plate 39 having an insertion hole 38 in the center thereof and a cylindrical main plate 39 having a substantially truncated cone-shaped outer surface and continuing coaxially with the insertion hole 38 are formed. A hub 40 protruding from the circular main plate 39 to one axial side of the insertion hole 38, and a twisted portion 41a which is twisted up at the end on the hub 40 side. A plurality of blade portions 41 protruding from the circular main plate 39 and the hub 40 to one side in the axial direction are provided integrally with the impeller body 35 made of resin at positions avoiding mutual overlap when viewed from the direction. A cutout hole 42 having a shape including the projection of the blade portion 41 in the axial direction of the insertion hole 38 is formed in the impeller body 35 , and the circular main plate 39 , the hub 40 and the blades are filled in the cutout hole 42 . A resin interpolation member 36 having an interpolation portion 44 smoothly connected to the surface of the portion 41 is brought into contact with the impeller main body 35 from the other side of the insertion hole 38 in the axial direction.

Therefore, even if the blade portion 41 has a three-dimensional shape with a twisted portion 41a, it is possible to avoid an undercut shape during resin molding. By filling with the interpolating portion 44, the centrifugal impeller having the highly efficient three-dimensional blade portion 41 can be manufactured at low cost and thin. In addition, a mold device for molding such a centrifugal impeller does not require slide cores, curved cores, drawing cores, etc., and movable mechanisms for moving them, so that manufacturing costs can be significantly reduced. In addition, by eliminating the need for a moving mechanism, it is possible to create multiple cavities in the extra space, using a so-called "multi-cavity resin molding die" to produce a large amount of centrifugal impeller parts at once. Therefore, a three-dimensional centrifugal impeller can be manufactured at low cost.

Further, the circular main plate 39 and the plurality of blade portions 41 are provided with cutout portions 50 that are arranged near the outer circumference of the circular main plate 39 and open to the outer circumference of the circular main plate 39, and fill the cutout portions 50. A plurality of welding bosses 51 protruding toward the front plate 37 are provided integrally with the interpolation member 36 while having an outer end surface 51a that continues to the outer periphery of the interpolation member 36 . are formed in the front plate 37, and the tip of the welding boss 51 is welded to the recess 53, so that the interpolating member 36 is formed between the impeller main body 35 and the front plate 37 are connected and fixed at once, thereby making it possible to easily manufacture a three-dimensional centrifugal impeller. Moreover, the welding boss portion 51 is welded in a state of being loosely fitted in the concave portion 53 of the front plate 37 at a position closer to the outer periphery of the front plate 37, thereby enhancing the gas release property during welding. Poor welding can be prevented from occurring.

Further, at a position spaced inwardly from the outer end surface 51a of the welding boss portion 51, a tip portion of the welding boss portion 51 has a triangular vertical cross-sectional shape before the welding boss portion 51 is welded to the concave portion 53. Since the projecting portion 52 is integrally protruded, the projecting portion 52 at the tip portion of the welding boss portion 51 can be easily melted during welding, and the melted resin can be suppressed from protruding to the outer peripheral side of the centrifugal impeller. This eliminates the need for deburring finishing such as shot blasting after the welding process.

In addition, welding surfaces 54 for welding at least the projections 52 are disposed on both sides of the welding surfaces 54 in the circumferential direction of the front plate 37 at the closed ends of the recesses 53 before the projections 52 are welded. Since the release groove 55 is formed, the gas generated during welding is released to the outer peripheral side of the front plate 37, and the melted resin during welding is prevented from overflowing to the outer periphery of the centrifugal impeller. can be made unnecessary.

Moreover, since the end portion of the escape groove 55 on the outer peripheral side of the front plate 37 is set at a position spaced inwardly from the outer periphery of the front plate 37, the escape groove 55 opens to the outer periphery of the front plate 37. The melted resin is stored in the escape groove 55 side while preventing the occurrence of defective welding by releasing the gas generated when the resin melts from the escape groove 55 to the outer peripheral side of the front plate 37. Furthermore, it is possible to more reliably prevent the resin melted during welding from protruding to the outer peripheral side of the centrifugal impeller, thereby eliminating the need for deburring finishing.

Furthermore, in manufacturing the centrifugal impeller 9, the impeller main body 35 having the notch 50, the front plate 37 having the recess 53, and the welding boss 51 provided with the protrusion 52 at the tip end thereof. and a step of injection molding each of the interpolating members 36 having the impeller main body while fitting the welding boss 51 loosely in the recess 53 and bringing the protrusion 52 into contact with the closed end of the recess 53. 35, in a state where the front plate 37 and the interpolating member 36 are overlapped, at least the protrusion 52 is heated and melted to weld the welding boss 51 to the recess 53. The interpolating member 36, the impeller main body 35 and the front plate 37 can be connected and fixed at once while preventing melted resin from protruding to the outer periphery of the centrifugal impeller. can be simplified, and a thin centrifugal impeller having a highly efficient three-dimensional blade portion 41 can be manufactured at low cost. .

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various design changes may be made without departing from the scope of the present invention described in the claims. is possible.

8 Support shaft 9 Centrifugal impeller 35 Impeller main body 36 Interpolation member 37 Front plate 38 Insertion hole 39 Circular main plate 40 Hub 41 Blade portion 41a Twisted portion 42 Cutout hole 44 Interpolation portion 50 Notch portion 51 Welding boss portion 51a Outer end face 52 of welding boss portion ... Projection 53 ... Recess 54 ... Welding surface 55 ... Relief groove

Claims (7)

A circular main plate (39) having an insertion hole (38) in the center through which the support shaft (8) is inserted, and a cylindrical main plate (39) having a substantially frustoconical outer surface and coaxially connected to the insertion hole (38). A hub (40) is formed and protrudes from the circular main plate (39) to one axial side of the insertion hole (38), and a twisted portion (41a) is twisted up on the side of the hub (40). and projecting from the circular main plate (39) and the hub (40) to one side in the axial direction at positions avoiding mutual overlap when viewed from the axial direction of the insertion hole (38). In a centrifugal impeller comprising a blade portion (41),
The circular main plate (39), the hub (40) and the blade portion (41) are integrally provided in an impeller body (35) made of resin. A cutout hole (42) having a shape that includes the projection of the blade portion (41) in the axial direction of is formed, and the circular main plate (39), the hub (40) and the blade are filled in the cutout hole (42). A resin interpolation member (36) having an interpolation portion (44) smoothly connected to the surface of the portion (41) abuts against the impeller body (35) from the other axial side of the insertion hole (38). A front plate (37) made of resin is brought into contact with the plurality of blades (41) from the side opposite to the interpolating member (36), and the circular main plate (39) and the plurality of blades (41) are in contact with each other. , a notch portion (50) arranged near the outer circumference of the circular main plate (39) and opening to the outer circumference of the circular main plate (39) is formed, and the front plate (37) is filled while filling the notch portion (50). ) side projecting integrally with the interpolating member (36) while having an outer end face (51a) that continues to the outer periphery of the interpolating member (36). The front plate (37) is formed with a plurality of recesses (53) into which the tips of the welding bosses (51) are loosely fitted, and the tips of the welding bosses (51) are welded to the recesses (53). A centrifugal impeller characterized by: A welding surface (54) to which the tip of the welding boss (51) is welded to the closed end of the recess (53), and both sides of the welding surface (54) in the circumferential direction of the front plate (37). 2. The centrifugal impeller according to claim 1, characterized in that relief grooves (55) arranged in are formed. 2. An end portion of the escape groove (55) on the outer peripheral side of the front plate (37) is set at a position spaced inwardly from the outer periphery of the front plate (37). Centrifugal impeller according to . 2. A centrifugal impeller manufacturing method for manufacturing the centrifugal impeller according to claim 1, wherein the welding boss portion (51) is spaced inwardly from the outer end surface (51a) of the welding boss portion (51). A protrusion (52) having a triangular vertical cross-section is integrally provided at the tip of (51) before the welding boss (51) is welded to the recess (53). A method for manufacturing a centrifugal impeller. a welding surface (54) for welding at least the projection (52) to the closed end of the recess (53) before the projection (52) is welded, and a circumferential direction of the front plate (37); 5. The method of manufacturing a centrifugal impeller according to claim 4 , wherein relief grooves (55) arranged on both sides of the welding surface (54) are formed. The end of the escape groove ( 55 ) on the outer peripheral side of the front plate (37) is set at a position spaced inwardly from the outer periphery of the front plate (37). 5. The method for manufacturing the centrifugal impeller according to 5. 2. The centrifugal impeller manufacturing method for manufacturing the centrifugal impeller according to claim 1 , wherein the impeller body (35) having the notch (50) and the front plate (35) having the recess (53) ( 37) and injection molding of the interpolating member (36) having the welding boss (51) provided with a projection (52) having a triangular vertical cross section at the tip; and the welding boss ( 51) is loosely fitted into the recess (53) and the protrusion (52) is brought into contact with the closed end of the recess (53), the impeller main body (35), the front plate (37) and a step of heating and melting at least the protrusion (52) with the interpolating member (36) superimposed to weld the welding boss (51) to the recess (53); A method for manufacturing a centrifugal impeller.

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