JP2016044570A - Impeller and method for manufacturing impeller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an impeller that is inexpensive and has high-dimensional accuracy, and to provide a method for manufacturing an impeller.SOLUTION: The impeller 1 includes: an impeller body 10 in which a front shroud 11 having an opened projection 11a, multiple vanes 12 provided to the front shroud 11 and a boss part 13 provided at the multiple vanes 12, into which a rotation axis is inserted are integrally formed; and a back shroud 14 mechanically fixed to the impeller body 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an impeller used for a pump and a method for manufacturing the impeller.

  Currently, as an impeller used for a pump for supplying a liquid such as water, a so-called closed impeller is known in which a plurality of blades arranged in the circumferential direction are arranged between a pair of disk-shaped shrouds. .

  As a method for manufacturing such an impeller, a technique of integrally molding using a main mold and a core formed in a blade shape and a shroud shape is known. However, the blade is often configured to be inclined with respect to the axial direction or curved from the outer peripheral edge of the impeller toward the center, and since the blade and the shroud are integrally formed, There is a problem that the core cannot be easily removed from the molded product.

  In order to solve such a problem, a technique is known in which a core is formed from a water-soluble resin material and the core is removed from the impeller by making the core water-soluble after impeller molding. In addition, as another method for manufacturing an impeller, a so-called lost wax manufacturing method using a technique in which a mold that forms a flow path in an impeller is slid or a mold formed by laminating ceramic materials around a wax mold is used. A technique using this is also known.

  In addition, a technique is also known in which a front shroud, a plurality of blades, and a back shroud are separately press-molded, and these components are mechanically fixed to assemble them integrally. As a method of mechanically fixing the shroud, screws are formed on the front shroud and the back shroud and fastened to each other, a structure in which the front shroud and the back shroud are fastened by bolts, etc., and the front shroud, blades and A configuration in which the back shroud is integrally fixed is known.

  There is also known a technique for forming an impeller by forming a part of a front shroud and a plurality of parts constituting one blade, and fitting these parts to a base plate and assembling them integrally. Reference 1).

JP 2005-098239 A

  The impeller as described above has the following problems. That is, when the impeller is manufactured using the above-described core and when the impeller is manufactured using the lost wax manufacturing method, the opening width of the discharge port on the outer peripheral edge of the impeller, that is, the front shroud and the back shroud There is a limit to the width between.

  That is, when the opening width of the discharge port of the impeller is narrow, there is a problem that it becomes difficult to manufacture the core because the core collapses. The lost wax manufacturing method also has a problem that the ceramic material does not enter the impeller and the mold cannot be molded.

  Moreover, it is difficult to process the inside of the impeller manufactured by such casting, and there is a possibility that variations in surface roughness and dimensional accuracy may occur. Furthermore, when manufacturing an impeller by press molding, there are a problem that the manufacturing process increases, a problem of strength when fixing each component, and the like.

  In addition, when an impeller is configured by fitting a plurality of parts to a base plate, there is a problem that high dimensional accuracy is required and manufacturing cost increases.

  Therefore, an object of the present invention is to provide an impeller that is inexpensive and has high dimensional accuracy, and a method for manufacturing the impeller.

  In order to solve the problems and achieve the object, the impeller and the method for manufacturing the impeller of the present invention are configured as follows.

  As one aspect of the present invention, an impeller includes a front shroud having a projecting portion that opens, a plurality of blades provided on the front shroud, and a boss portion that is provided on the plurality of blades and into which a rotation shaft is inserted. A molded impeller body, and a back shroud that is mechanically fixed to the impeller body.

  As one aspect of the present invention, an impeller manufacturing method includes a front shroud having a projecting portion that opens, a plurality of blades provided on the front shroud, and a boss portion that is provided on the plurality of blades and into which a rotating shaft is inserted. An impeller body made of is integrally formed, and a back shroud is mechanically fixed to the impeller body.

  According to the present invention, it is possible to provide an impeller that is inexpensive and has high dimensional accuracy, and a method for manufacturing the impeller.

Sectional drawing which shows the structure of the impeller which concerns on one Embodiment of this invention. The top view which shows the structure of the impeller. The top view which shows the principal part structure of the impeller. Explanatory drawing which shows an example of the manufacturing method of the impeller.

Hereinafter, an impeller 1 according to an embodiment of the present invention and a method for manufacturing the impeller 1 will be described with reference to FIGS. 1 to 4.
FIG. 1 is a cross-sectional view showing the configuration of an impeller 1 according to an embodiment of the present invention, FIG. 2 is a plan view showing the configuration of the impeller 1 from the side of the front shroud 11, and FIG. These are the top views which show the structure of the front shroud 11, the blade | wing 12, and the boss | hub part 13 from the boss | hub part 13 side, FIG. 4 is explanatory drawing which shows an example of the manufacturing method of the impeller 1. FIG.

  As shown in FIGS. 1 to 3, the impeller 1 includes a front shroud 11, a plurality of blades 12, a boss portion 13, and a back shroud 14. In the impeller 1, a front shroud 11, a plurality of blades 12, and a boss portion 13 are integrally formed by casting. In other words, the impeller 1 includes a front shroud 11, an impeller body 10 in which a plurality of blades 12 and a boss portion 13 are integrally formed, and a back shroud 14.

  In the impeller 1, the back shroud 14 is mechanically fixed to the impeller body 10 by welding or fastening with a fastening member.

  The impeller 1 has a discharge port formed on the outer peripheral side thereof. The impeller 1 has a suction port formed at the center of the front shroud 11. The impeller 1 is used for a pump.

  For example, the impeller 1 is disposed in a pump casing of a pump and is fixed to a rotating shaft connected to a motor. Such an impeller 1 has a rotating shaft that is rotated by a motor so that liquid, for example, water is sucked from the suction port, and water passing through the pressure is increased and discharged from the discharge port. It is configured to be capable of being pumped to the next side.

  The front shroud 11 is formed in a disk shape, and has a cylindrical protrusion 11a whose center is open. The opening of the protrusion 11a is formed so that the rotation shaft of the pump can be inserted. The opening of the protruding portion 11a constitutes a suction port of the impeller 1.

  A plurality of, for example, six blades 12 are arranged on one main surface of the front shroud 11 at equal intervals. The blades 12 are curved and extended in an arc shape from the outer peripheral edge of the front shroud 11 to the center side of the front shroud 11.

  For example, the blade 12 is formed so that the edge continuous with the front shroud 11 is inclined so that the height gradually increases from the outer peripheral side of the front shroud 11 toward the center side. The blades 12 are formed so that the thickness thereof is substantially the same or gradually increases from the center side to the outer peripheral side.

  The blade 12 is formed so that the inner diameter of the blade 12 formed by the plurality of blades 12 is minimized on the back shroud 14 side by tilting the end portion located on the center side of the front shroud 11 with respect to the axial direction. Is done. Here, as shown in FIG. 1, the blade inner diameter is an inner diameter formed by the plurality of blades 12, more specifically, the impeller 1 passing through the ends of the plurality of blades 12 on the center side of the impeller 1. It is a virtual circle centered on the axis, and D1 in FIG. 1 indicates the minimum blade inner diameter.

  The boss portion 13 has an insertion hole 13b formed with a key groove 13a into which the rotation shaft of the pump can be inserted. The boss portion 13 is formed with, for example, the same diameter from one end portion to the midway portion, and the outer diameter gradually increases from the midway portion toward the other end portion, and at the other end portion, The back shroud 14 is formed with the same outer diameter over a length equal to or greater than the thickness. The outer shape of the boss 13 is formed at the other end so as to have the maximum outer diameter.

  As shown in FIG. 1, the minimum blade inner diameter D1 of the blade 12 and the maximum outer diameter D2 of the boss portion 13 are set so that the minimum blade inner diameter D1 of the blade 12 ≦ the maximum outer diameter D2 of the boss portion 13. .

  The back shroud 14 is formed in a circular plate having an opening 14a at the center, in other words, an annular shape. The inner diameter of the opening 14a is formed to be the same as the maximum outer diameter D2 of the boss 13. The back shroud 14 is integrally fixed to the blade 12 or the blade 12 and the boss portion 13 by welding or a fastening member.

Next, a method for manufacturing the impeller 1 configured as described above will be described with reference to FIG.
First, as shown in step ST1 in FIG. 4, the impeller body 10 is molded by casting using a core or a lost wax manufacturing method. The impeller body 10 is not limited to this, and may be formed by other forming methods, but the front shroud 11, the plurality of blades 12, and the boss portion 13 are integrally formed.

  Next, the mold is removed from the molded impeller body 10. In the case of casting using a core, the core is removed. In the case of molding using the lost wax manufacturing method, a material constituting the mold, for example, a ceramic material is removed.

  Next, the surface of the impeller body 10 from which the mold has been removed is processed as necessary. For example, the processing includes shot blasting, cutting or polishing.

  Next, as shown in step ST <b> 2 in FIG. 4, the back shroud 14 is aligned with the impeller body 10. Specifically, the opening 14 a of the back shroud 14 is engaged with the boss 13, and one main surface of the back shroud 14 is brought into contact with the blade 12.

  In addition, when the back shroud 14 is disposed on the impeller body 10 and each portion of the impeller body 10 and the back shroud 14 are not in proper contact, the impeller body 10 or the back shroud 14 is additionally processed.

  Next, as shown in step ST3 in FIG. 4, the back shroud 14 is mechanically welded to the plurality of blades 12 and the first boss portion 13 of the impeller body 10 using, for example, a welding device 20, and the impeller body 10 And the back shroud 14 is fixed. Thereby, the impeller body 10 and the back shroud 14 are assembled together, and the impeller 1 is manufactured.

  In addition, as a method of mechanically assembling the back shroud 14 to the impeller body 10, an internal thread portion is processed in the blade 12 using the processing device 20, an insertion hole is processed in the back shroud 14, and fastening by a fastening member is performed. Thus, the impeller body 10 and the back shroud 14 may be assembled.

  According to the impeller 1 configured as described above, the impeller 1 is manufactured by mechanically fixing the back shroud 14 to the impeller body 10 in which the front shroud 11, the plurality of blades 12 and the boss portion 13 are integrally formed. is there. For this reason, the impeller body 10 is formed by opening between the plurality of blades 12 on the side where the back shroud 14 is attached. For this reason, it becomes easy to provide a material constituting a mold such as a core or a ceramic material between the blades 12. In addition, it becomes easy to remove the material constituting the mold from the impeller body 10.

  For this reason, the manufacture of the impeller 1 is easy and the width of the discharge port of the impeller 1 that can be manufactured is not limited.

  Further, since the blades 12 can be processed, it is easy to improve the accuracy of the width of the discharge port of the impeller 1. In particular, the opening width and the opening area of the discharge port of the impeller 1 affect the performance. However, since the blades 12 of the molded impeller body 10 can be easily processed, it is possible to reduce variations in the performance of the impeller 1. Similarly, the adjustment of the outer diameter of the impeller 1 can be performed by processing the impeller body 10 or the back shroud 14, so that the performance of the impeller 1 can be easily adjusted. Furthermore, since the back shroud 14 can be easily processed to adjust the outer diameter, it can be shared by the impeller body 10 having different outer diameters, and the component cost can be reduced.

  Further, since the impeller body 10 opens between the blades 12 on the side where the back shroud 14 is provided, it is easy to check the state of the blades 12, that is, visually. Thereby, confirmation of the casting surface inside the blade | wing 12 used as a flow path becomes easy, and it becomes possible to shorten an inspection process. In addition, even when the casting surface is not good, since the processing is easy, the performance and quality can be improved. As described above, the impeller body 10 and the back shroud 14 are mechanically and integrally assembled, whereby the impeller 1 having high dimensional accuracy and capable of reducing the manufacturing cost can be obtained.

  Further, since the back shroud 14 can use a flat disk-like shape, it can be easily fixed to the mechanical impeller body 10 by welding or the like, and is easy to assemble.

  Further, the impeller body 10 is configured so that the minimum blade inner diameter D1 of the blade 12 is equal to or less than the maximum outer diameter D2 of the boss portion 13, so that the front shroud 11 and the boss portion 13 are integrally formed via the blade 12. Is done. For this reason, the impeller body 10 can obtain high strength. Thereby, even when the pump casing and the projecting portion 11a of the front shroud 11 are fixed by biting or the like when the pump is driven, it is possible to sufficiently secure the strength capable of preventing the impeller 1 from being damaged.

  As described above, according to the impeller 1 and the method for manufacturing the impeller 1 according to the embodiment of the present invention, the impeller 1 is inexpensive and can have high dimensional accuracy.

  The present invention is not limited to the above embodiment. For example, although the above-described impeller 1 has been described with the structure in which the impeller body 10 and the back shroud 14 are integrally assembled by welding or fixing by a fastening member, the present invention is not limited to this, and other mechanical fixing methods may be used. . For example, it may be configured such that caulking, a screw portion is formed in the opening 14a of the boss portion 13 and the back shroud 14 and screwed together.

  Moreover, although the impeller 1 demonstrated the structure used for a pump in the example mentioned above, the said pump can be used for various pumps, such as a single stage pump and a multistage pump. In addition, various modifications can be made without departing from the scope of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Impeller, 10 ... Impeller main body, 11 ... Front shroud, 12 ... Blade | wing, 13 ... Boss part, 14 ... Back shroud, 20 ... Welding apparatus (processing apparatus).

Claims (11)

A front shroud having a projecting portion that opens, a plurality of blades provided in the front shroud, and an impeller body formed integrally with a boss portion provided in the plurality of blades and inserting a rotation shaft;
A back shroud fixed to the impeller body;
An impeller characterized by comprising:   The impeller according to claim 1, wherein the back shroud is fixed to the impeller body by welding.   The impeller according to claim 1, wherein the back shroud is fixed to the impeller body using a fastening member.   2. The impeller according to claim 1, wherein the back shroud has a flat surface facing the plurality of blades.   The impeller according to claim 1, wherein a minimum blade inner diameter of the plurality of blades is formed to be equal to or smaller than a maximum outer diameter of the boss portion. A front shroud having a projecting portion that opens, a plurality of blades provided on the front shroud, and an impeller body that is provided on the plurality of blades and includes a boss portion into which a rotation shaft is inserted, are integrally formed,
Fixing a back shroud to the impeller body;
An impeller manufacturing method characterized by the above.   The impeller manufacturing method according to claim 6, wherein the impeller body or the back shroud is processed before the back shroud is mechanically fixed to the impeller body.   The impeller manufacturing method according to claim 6, wherein the back shroud is fixed to the impeller body by welding.   The impeller manufacturing method according to claim 6, wherein the back shroud is fixed to the impeller body using a fastening member.   The impeller manufacturing method according to claim 6, wherein the back shroud has a flat surface facing the plurality of blades.   The impeller manufacturing method according to claim 6, wherein a minimum blade inner diameter of the plurality of blades is formed to be equal to or smaller than a maximum outer diameter of the boss portion.

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