impeller

Abstract

An impeller (1) has attached thereto a metal shaft (SH) and is formed of a resin member (RE). The resin member (RE) comprises: a first portion (10) that includes a gate mark (GE); a second portion (20) that does not include the gate mark (GE); and a connection portion (30) that connects the first portion (10) and the second portion (20) and forms a recess (31).

Description

impeller

[0001] The present invention relates to an impeller.

[0002] It is known to manufacture an impeller by using a shaft as an embedded metal fitting and pouring molten resin into a cavity (see, for example, Patent Document 1).

[0003] Japanese Patent Application Publication No. 10-166398

[0004] However, with conventional manufacturing methods, it may not be possible to fill the cavity evenly with resin, which may cause the center of gravity to shift from the center of rotation.

[0005] The present invention has been made in view of the above, and has an object to provide an impeller that can prevent the center of gravity from shifting from the center of rotation.

[0006] In order to solve the above-mentioned problems and achieve the object, the impeller of the present invention is formed of a resin member having a metal shaft attached thereto, and the resin member has a first portion including the gate mark, a second portion not including the gate mark, and a connecting portion connecting the first portion and the second portion and forming a recess.

[0007] According to one aspect of the impeller of the present invention, it is possible to provide an impeller that can prevent the center of gravity from shifting from the center of rotation.

[0008] FIG. 1 is a perspective view of an impeller according to a first embodiment. FIG. 2 is a cross-sectional view of the impeller shown in FIG. 1. FIG. 3 is a perspective view of the impeller shown in FIG. 1 as viewed from the front side. FIG. 4 is a cross-sectional view of a mold used in manufacturing a resin member included in the impeller shown in FIG. 1. FIG. 5 is a perspective view of a plurality of nozzles used in manufacturing the resin member included in the impeller shown in FIG. 1. FIG. 6 is a front view showing the time it takes for molten resin to reach the impeller of a comparative example when manufactured by molding. FIG. 7 is a front view showing the time it takes for molten resin to reach the impeller of the comparative example when manufactured by molding. FIG. 8 is a perspective view of an impeller according to a second embodiment. FIG. 9 is a partial cross-sectional view of a portion of the impeller shown in FIG. 8. FIG. 10 is a cross-sectional view of a portion of a mold used to manufacture the impeller shown in FIG. 8. FIG. 11 is a cross-sectional view of a portion of the impeller of the comparative example. FIG. 12 is a front view showing the time it takes for molten resin to reach the impeller of the comparative example when manufactured by molding. FIG. 13 is a front view showing the time at which molten resin reaches the impeller shown in FIG. 8 when the impeller is manufactured by molding.

[0009] The impeller according to the embodiment will be described in detail below with reference to the drawings. Note that the dimensional relationships and ratios of elements in the drawings may differ from the actual situation. The dimensional relationships and ratios may also differ between the drawings.

[0010] [First embodiment] Fig. 1 is a perspective view of an impeller 1 according to a first embodiment. Fig. 2 is a cross-sectional view of the impeller 1 shown in Fig. 1. Fig. 3 is a perspective view of the impeller 1 shown in Fig. 1 as seen from the front side.

[0011] In the description of the impeller 1 shown in FIG. 1 according to the first embodiment, in order to facilitate understanding of directions, the direction in which a shaft SH described later extends will be referred to as the axial direction A, the direction in which the shaft SH described later rotates will be referred to as the circumferential direction C, and the direction that is included in a plane perpendicular to the axial direction A, passes through the axis SHX of the shaft SH, and is perpendicular to the circumferential direction C will be referred to as the radial direction R.

[0012] 1 to 3 is used in a fan that is built into, for example, an electronic device and is used to cool components provided inside the device. In this type of impeller 1, a shaft SH is connected to the output shaft of a motor, and as the motor is driven, the shaft SH rotates together with the output shaft in a circumferential direction C, thereby blowing air onto the components.

[0013] The impeller 1 includes a shaft SH and a resin member RE. The shaft SH is a so-called rotating shaft, is made of metal, and is formed in a cylindrical shape extending along the axial direction A. The shaft SH has an axis SHX extending along the axial direction A, and is provided to be rotatable around the axis SHX.

[0014] The resin member RE has a cylindrical shape with a bottom and includes a first portion 10 including a gate mark GE, a second portion 20 not including the gate mark GE, and a connecting portion 30 connecting the first portion 10 and the second portion 20 and having a recess 31 formed therein.

[0015] The first portion 10 is a top surface portion 11 that is perpendicular to the axial direction A in which the axis SHX of the shaft SH extends. More specifically, the top surface portion 11 is formed, for example, in the shape of a circular plate when viewed from the axial direction A. The top surface portion 11 according to this embodiment has multiple gate marks GE. More specifically, the top surface portion 11 has seven gate marks GE. The gate marks GE are arranged in a row near the attachment position of the shaft SH on the top surface portion 11. Furthermore, the gate marks GE are arranged around the axis SHX and spaced apart in the circumferential direction C.

[0016] The second portion 20 is a wall portion 21 provided with a plurality of blades 22 and extending along the axial direction A. More specifically, the wall portion 21 is formed, for example, in a cylindrical shape. In addition, seven blades 22 are provided on the wall portion 21 according to this embodiment.

[0017] In the connecting portion 30, a recess 31 is disposed at a position where the second portion 20 is bent and connected to the first portion 10. The recess 31 is continuous in the circumferential direction C and goes around the circumference of the shaft SH. The recess 31 is also formed on the inner surface of the resin member RE. Furthermore, the recess 31 of the impeller 1 according to this embodiment is thinner than the top surface portion 11 and also thinner than the wall portion 21.

[0018] Next, a manufacturing method of the resin member RE will be described with reference to Figures 4 and 5. Figure 4 is a cross-sectional view of a mold MO used when manufacturing the resin member RE of the impeller 1 shown in Figure 1. Figure 5 is a perspective view of a plurality of nozzles NO used when manufacturing the resin member RE of the impeller 1 shown in Figure 1. As shown in Figure 4, a cavity CA is provided inside the mold MO. The shape of the cavity CA corresponds to the shape of the resin member RE. Also, a columnar member MO1 having the same shape and size as the shaft SH is arranged inside the mold MO.

[0019] 4 are used to inject molten resin into the cavity CA from an opening MO2 provided in the mold MO. The number of nozzles NO according to this embodiment is, for example, seven, including three first nozzles NO1 and four second nozzles NO2.

[0020] When manufacturing a resin member RE by molding using a mold MO, the worker first places the tip of the nozzle NO in the opening MO2 of the mold MO, and then injects molten resin from each nozzle NO into the cavity CA.

[0021] At this time, the molten resin spreads around the nozzle NO, centered on the nozzle NO, and then spreads to the portion CA11 corresponding to the top surface portion 11 (first portion 10) of the cavity CA. When the molten resin reaches the portion CA31 corresponding to the recess 31 of the cavity CA, the resistance to the flow of the molten resin through the portion CA31 corresponding to the recess 31 is high. Therefore, the molten resin hardly flows in the direction indicated by the arrow F1 in FIG. 4 , but flows along the radial direction R. In other words, the portion CA31 with high fluid resistance blocks the molten resin. In other words, the portion CA31 corresponding to the recess 31 of the cavity CA functions to wait for the pressure of the molten resin to increase. In other words, the portion CA31 corresponding to the recess 31 of the cavity CA functions to adjust the timing at which the resin flows beyond the portion CA31.

[0022] After that, when the resin flows into all of the portion CA11 corresponding to the top surface portion 11 of the cavity CA, the molten resin flows to the portion CA21 corresponding to the wall portion 21 (second portion 20) via the recess 31, and therefore the molten resin flows in the direction indicated by the arrow F1 around the entire radial direction R of the recess 31.

[0023] The worker then pours the resin into the entire portion CA11 corresponding to the wall portion 21, applies a holding pressure to the resin, and then stops pouring the molten resin into the cavity CA. The worker then cools the molten resin to produce the resin member RE, and then removes the resin member RE from the mold MO. Finally, the shaft SH is attached to the resin member RE, thereby completing the production of the impeller 1.

[0024] Next, an impeller 1Y of a comparative example and the impeller 1 according to this embodiment will be described with reference to FIGS. 6 and 7 . FIG. 6 is a front view showing the time it takes for molten resin to reach the impeller 1Y of the comparative example when manufactured by molding. FIG. 7 is a front view showing the time it takes for molten resin to reach the impeller 1 shown in FIG. 1 when manufactured by molding. Note that in FIGS. 6 and 7 , the times shown on the right side indicate the time [seconds] from when the molten resin is injected from the nozzle NO until the molten resin reaches each part. The impeller 1Y of the comparative example has the same shape as the impeller 1 according to this embodiment, except that it does not have the recess 31.

[0025] 6, when 0.45 seconds have elapsed since the molten resin was injected from the nozzle NO, there are portions 1YA where the molten resin has exceeded the portion corresponding to the recess 31 and portions 1YB where the molten resin has not exceeded the portion corresponding to the recess 31, and there is a bias in the portion where the molten resin is present. In other words, with the impeller 1Y of the comparative example, the resin filling the mold MO is uneven.

[0026] In this comparison, in the nozzles NO used to manufacture the impeller 1 according to this embodiment, the diameter of each gate of the first nozzle NO1 is, for example, 0.8 mm. On the other hand, the diameter of each gate of the second nozzle NO2 is, for example, 1.6 mm. In other words, the impeller 1 was manufactured in a state where there was a risk that the resin filling the cavity CA would be uneven.

[0027] 7, when 0.45 seconds have elapsed since the molten resin was injected from the nozzle NO, the molten resin has exceeded the recesses 31 over the entire circumference in the radial direction R, and there is no unevenness in the areas where the resin is present. In other words, in the impeller 1 according to this embodiment, the resin filled into the mold MO is uniform.

[0028] As described above, the impeller 1 according to this embodiment is formed of a resin member RE and includes a metal shaft SH. The resin member RE includes a first portion 10 including a gate mark GE, a second portion 20 not including a gate mark GE, and a connecting portion 30 connecting the first portion 10 and the second portion 20 and having a recess 31 formed therein. Therefore, when manufacturing the impeller 1 according to this embodiment, the recess 31 allows the resin to be filled into each portion of the cavity CA so that the molten resin is uniform. Therefore, when the impeller 1 according to this embodiment rotates the blades 22 in the circumferential direction C, the center of gravity of the impeller 1 can be prevented from shifting from the center of rotation relative to the axis SHX of the shaft SH.

[0029] In the impeller 1 of this embodiment, the first part 10 is a top surface portion 11 that is perpendicular to the axial direction A along which the axis SHX of the shaft SH extends, and the second part 20 is a wall portion 21 that is provided with a plurality of blades 22 and extends along the axial direction A, and a recess 31 is arranged at a position where the second part 20 is connected to the first part 10 so as to bend.

[0030] In the impeller 1 according to this embodiment, the resin member RE has a cylindrical shape with a bottom, and a recess 31 is formed on the inner surface of the resin member RE.

[0031] In the impeller 1 according to this embodiment, the recess 31 is provided radially outward of the gate mark GE.

[0032] In the impeller 1 according to this embodiment, the gate marks GE are arranged side by side near the attachment position of the shaft SH on the top surface portion 11 .

[0033] In the impeller 1 according to the embodiment described above, the shaft SH and the resin member RE are manufactured separately, and then the shaft SH is attached to the resin member RE. However, the impeller 1 according to the embodiment is not limited to this. For example, the impeller 1 according to the embodiment may be manufactured by insert molding, in which a pre-manufactured shaft SH is fixed to a mold MO instead of the columnar member MO1, and then molten resin is injected into the cavity CA of the mold MO.

[0034] Furthermore, the impeller 1 according to the above embodiment has been described as being formed using a plurality of nozzles NO with different gate diameters. However, the impeller 1 according to the present embodiment is not limited to this. For example, the impeller 1 may be formed using a plurality of nozzles NO with the same gate diameter.

[0035] Second Embodiment Next, an impeller 1A according to a second embodiment will be described with reference to Figures 8, 9, and 10. Figure 8 is a perspective view of the impeller 1A according to the second embodiment. Figure 9 is a partial cross-sectional view of a portion of the impeller 1A shown in Figure 8. Figure 10 is a cross-sectional view of a portion of a mold MOA used to manufacture the impeller 1A shown in Figure 8. Note that in the configuration of the impeller 1A according to the second embodiment, the same components as those of the impeller 1 according to the first embodiment are designated by the same reference numerals, and description thereof will be omitted.

[0036] The impeller 1A includes a shaft SH (not shown) and a resin member REA. The resin member REA includes a first portion 10A including a gate mark GE, a second portion 20A not including the gate mark GE, and a connecting portion 30A connecting the first portion 10A and the second portion 20A and having a recess 31A formed therein.

[0037] In the impeller 1A according to this embodiment, the resin member REA includes a bottom surface portion 11A, a wall portion 12A, a top surface portion 13A, a plurality of blades 14A, and an annular portion 32A.

[0038] The bottom surface portion 11A has a plurality of gate marks GE and is perpendicular to the axial direction A in which the axis SHX of the shaft SH extends. More specifically, when viewed from the axial direction A, for example, the bottom surface portion 11A is formed in a circular plate shape and is perpendicular to the axial direction A.

[0039] The wall portion 12A is connected to the bottom surface portion 11 A. More specifically, the wall portion 12A is formed in a cylindrical shape extending in the axial direction A, for example.

[0040] The top surface portion 13A is connected to the wall portion 12A and is perpendicular to the axial direction A. More specifically, when viewed from the axial direction A, the top surface portion 13A is formed in the shape of a circular plate, for example.

[0041] The plurality of blades 14A are connected to the top surface portion 13A and extend in the axial direction A. The resin member REA according to this embodiment has, for example, eleven blades 14A.

[0042] The annular portion 32A connects the tip ends of the plurality of blades 14A in the circumferential direction C. The annular portion 32A according to this embodiment is continuous in the circumferential direction C and goes around the periphery of the shaft SH (not shown).

[0043] The annular portion 32A has an inner annular portion 33A located on the inside in the radial direction R, an outer annular portion 34A located on the outside in the radial direction R, and a connecting portion 30A connecting the inner annular portion 33A and the outer annular portion 34A. The annular portion 32A forms a recess 31A by the inner annular portion 33A, the outer annular portion 34A, and the connecting portion 30A.

[0044] The thickness t33 of the inner annular portion 33A is, for example, 0.5 mm, the thickness t34 of the outer annular portion 34A is, for example, 0.5 mm, and the thickness t30 of the connecting portion 30A is, for example, 0.5 mm.

[0045] The first portion 10A includes a bottom surface portion 11A, a wall portion 12A, a top surface portion 13A, blades 14A, and an inner annular portion 33A.

[0046] The second portion 20A is an outer annular portion 34A. The annular portion 32A defines a recess 31A between the inner annular portion 33A, the outer annular portion 34A, and the connecting portion 30A. The recess 31A is continuous in the circumferential direction C and extends around the shaft SH. The recess 31A is also formed on the inner surface of the resin member REA.

[0047] The resin member REA according to this embodiment is formed by injecting molten resin into a mold MOA having a cavity CAA corresponding to the shape of the impeller 1A, similar to the impeller 1 according to the first embodiment.

[0048] At this time, the molten resin spreads around the nozzle NO, centered on the nozzle NO, and spreads to the part corresponding to the bottom surface portion 11A of the cavity CAA, the part corresponding to the wall portion 12A, the part corresponding to the top surface portion 13A, and the part corresponding to the blade 14A, for example in this order.

[0049] When the molten resin reaches the portion 33CA of the cavity CAA corresponding to the inner annular portion 33A, the resistance to the flow of the molten resin through the portion 30CA corresponding to the connecting portion 30A of the recess 31A is high. Therefore, the molten resin hardly flows in the direction indicated by the arrow F1A in FIG. 10 , and instead flows along the radial direction R at the portion 33CA. In other words, the molten resin is blocked by the portion 30CA with high fluid resistance. In other words, the portion 30CA of the cavity CAA functions to wait for the timing when the pressure of the molten resin increases. In other words, the portion 30CA of the cavity CAA corresponding to the connecting portion 30A functions to adjust the timing when the resin flows beyond the portion 30CA.

[0050] After that, when the resin has flowed into all of the portion 33CA corresponding to the inner annular portion 33A in the cavity CAA, the molten resin will flow to the portion 30CA corresponding to the connecting portion 30A in the cavity CAA and the portion 34CA corresponding to the outer annular portion 34A in the cavity CAA. Therefore, after the molten resin flows in the direction indicated by the arrow F1 around the entire radial direction R of the portion 30CA, the resin will flow into the portion 34CA corresponding to the outer annular portion 34A.

[0051] The worker then pours resin into the entire portion 34CA corresponding to the outer annular portion 34A, applies a holding pressure to the resin, and then stops pouring the molten resin into the cavity CAA. The worker then cools the molten resin to produce the resin member REA, and then removes the resin member REA from the mold MOA. Finally, the shaft SH is attached to the resin member REA, completing the production of the impeller 1A.

[0052] Next, an impeller 1Z of a comparative example and an impeller 1A according to this embodiment will be described with reference to Figures 11, 12, and 13. Figure 11 is a cross-sectional view of a portion of the impeller 1Z of the comparative example. Figure 12 is a front view showing the time it takes for molten resin to reach the impeller 1Z of the comparative example when manufactured by molding. Figure 13 is a front view showing the time it takes for molten resin to reach the impeller 1A shown in Figure 8 when manufactured by molding. In Figures 12 and 13, the times shown on the right side of the figures indicate the time [seconds] from when the molten resin is injected from nozzle NO until the molten resin reaches each part.

[0053] In the impeller 1Z of the comparative example, the thickness t33Z of the inner annular portion 33Z is, for example, 0.85 mm, the thickness t34Z of the outer annular portion 34Z is, for example, 0.85 mm, and the thickness t30Z of the connecting portion 30Z is, for example, 1.52 mm. In other words, the impeller 1Z of the comparative example has the same shape as the impeller 1A of the present embodiment, except that the depth of the recess 31Z is shallower than the depth of the recess 31A of the impeller 1A of the present embodiment.

[0054] 12, when 1.120 seconds had elapsed since the molten resin was injected from the nozzle NO, the molten resin had been injected into a portion of the outer annular portion 34A, but there were still portions 1ZA to which the molten resin had not yet been injected. In other words, with the impeller 1Z of the comparative example, the resin filling the mold MOA was uneven.

[0055] 13, when 1.12 seconds have elapsed since the molten resin was injected from the nozzle NO, the molten resin was injected into all parts of the outer annular portion 34A around the entire circumference in the radial direction R. In other words, in the impeller 1A according to this embodiment, the resin filling the mold MOA was uniform.

[0056] As described above, the impeller 1A according to this embodiment is formed of a resin member REA and includes a metal shaft SH attached thereto. The resin member REA includes a first portion 10A including a gate mark GE, a second portion 20A not including a gate mark GE, and a connecting portion 30A connecting the first portion 10A and the second portion 20A and including a recess 31A. Therefore, when manufacturing the impeller 1A according to this embodiment, the recess 31A allows the molten resin to be filled into each portion of the cavity CAA so that the resin is uniform. Therefore, when the impeller 1A according to this embodiment rotates the blades 14A in the circumferential direction C, the center of gravity of the impeller 1A can be prevented from shifting from the center of rotation relative to the axis SHX of the shaft SH.

[0057] In the impeller 1A according to this embodiment, the resin member REA includes a bottom surface portion 11A having a gate mark GE and perpendicular to an axial direction A along which an axis SHX of the shaft SH extends, a wall portion 12A connected to the bottom surface portion 11A, a top surface portion 13A connected to the wall portion 12A and perpendicular to the axial direction A, a plurality of blades 14A connected to the top surface portion 13A and extending in the axial direction A, and an annular portion 32A connecting the tips of the plurality of blades 14A in the circumferential direction C. The annular portion 32A includes an inner annular portion 33A located on the inside in the radial direction R, an outer annular portion 34A located on the outside in the radial direction R, and a connecting portion 30A connecting the inner annular portion 33A and the outer annular portion 34A. The first portion 10A includes the bottom surface portion 11A, the wall portion 12A, the top surface portion 13A, the blades 14A, and the inner annular portion 33A. The second portion 20A is an outer annular portion 34A. The annular portion 32A forms a recess 31A with the inner annular portion 33A, the outer annular portion 34A, and a connecting portion 30A.

[0058] The above has been a description based on the embodiments of the impellers 1 and 1A according to the present invention, but it goes without saying that the present invention is not limited to the embodiments and various modifications are possible without departing from the spirit of the present invention. The present invention also includes configurations in which the components of the above-described embodiments are appropriately combined. Such modifications without departing from the spirit of the present invention are also included in the technical scope of the present invention, and this will be clear to those skilled in the art from the claims.

[0059] DESCRIPTION OF SYMBOLS 1, 1A Impeller, 10, 10A First portion, 11, 13A Top surface portion, 11A Bottom surface portion, 12A Wall portion, 20, 20A Second portion, 21 Wall portion, 22 Blade, 30, 30A Connecting portion, 31, 31A Recess, 32A Annular portion, 33A Inner annular portion, 34A Outer annular portion, C Circumferential direction, GE Gate mark, R Radial direction, RE, REA Resin member, SH Shaft, SHX Axial core

Claims

1. An impeller having a metal shaft attached thereto and formed of a resin member, the resin member comprising: a first portion including a gate mark, a second portion not including the gate mark, and a connecting portion connecting the first portion and the second portion and having a recess formed therein.

2. An impeller as described in claim 1, wherein the first portion is a top surface portion perpendicular to an axial direction along which the axis of the shaft extends, the second portion is a wall portion having a plurality of blades and extending along the axial direction, and the recess is disposed at a position where the second portion is connected to the first portion in a bending manner.

3. The impeller according to claim 2, wherein the resin member is cylindrical with a bottom, and the recess is formed on an inner surface of the resin member.

4. An impeller as set forth in claim 2 or 3, wherein the recess is provided radially outward of the gate mark.

5. The impeller according to claim 4, wherein the gate marks are arranged side by side in the vicinity of a mounting position of the shaft on the top surface portion.

6. An impeller as described in claim 1, wherein the resin member comprises: a bottom surface portion having the gate mark and perpendicular to an axial direction along which an axis of the shaft extends; a wall portion connected to the bottom surface portion; a top surface portion connected to the wall portion and perpendicular to the axial direction; a plurality of blades connected to the top surface portion and extending in the axial direction; and an annular portion connecting tips of the plurality of blades in a circumferential direction; the annular portion has an inner annular portion located radially inward, an outer annular portion located radially outward, and a connecting portion connecting the inner annular portion and the outer annular portion; the first portion is the bottom surface portion, the wall portion, the top surface portion, the blades, and the inner annular portion; the second portion is the outer annular portion; and the annular portion forms the recess by the inner annular portion, the outer annular portion, and the connecting portion.

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