Molding method and molding device for forming impeller

A molding method for forming an impeller, includes a mold clamping process having a first mold for forming one side of blades, a second mold firmly clamped with the first mold, and a core arranged at the first mold relative to the blades, the mold clamping process clamping the first mold to the second mold in a state where the core is arranged between the first mold and the second mold, an injecting process injecting resin in a cavity obtained by the mold clamping process, and a mold removing process including the steps of releasing at least the first mold from the clamped state obtained by the mold clamping process to generate an opened portion in the first mold after the resin is hardened, rotating the core about a rotational axis toward the opened portion of the first mold, and separating the core from the resin-molded impeller.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 U.S.C. §119 to Japanese Patent Application 2010-244520, filed on Oct. 29, 2010, the entire content of which is incorporated herein by reference.

TECHNICAL FIELD

This disclosure generally relates to a molding method and a molding device for forming an impeller including a main body and plural blades arranged at the main body so as to circumferentially adjoin one another.

BACKGROUND DISCUSSION

A known die-casting technique to form an impeller by a lost wax casting process is disclosed in US2006/0291996A (hereinafter referred to as Reference 1). The impeller is generally adapted to a pump rotationally driven by a predetermined drive source so as to send fluid such as water and the like, or is generally adapted to an axial flow rotor such as a gas turbine engine and the like rotationally driven by operating fluid. In particular, the impeller disclosed in Reference 1 is an impeller of a supercharger for an engine and is made of metal or the like. A die for injection-forming a sacrificial pattern utilized to die-cast the impeller is explained in Reference 1.

The die includes slide dies each slidably supported by a slide support and rotatable about a rotational axis extending along a radial direction of the impeller. The slide die includes plural cores for forming blade surfaces of blades of the impeller. The cores are rotated about the rotational axis relative to the slide support in such a way that the blade surfaces may be formed to have cross sections which extend along a flat surface perpendicular to the radial direction of the impeller so as to be inclined to a rotational axle of the impeller.

After the injection-forming process, the slide supports are moved to an outward side in the radial direction of the impeller; therefore, the cores are separated from the die-cast blade surfaces to the outward side in the radial direction while rotating about the rotational axes extending along the radial direction.

In addition, a cam plate including plural cam grooves being radially curved is rotatably arranged around the rotational axle of the impeller. The cam grooves are engaged with respective lower surfaces of the slide supports. The cam plate serves as a mechanism to separate the plural cores in conjunction with one another from the die-cast impeller toward the outward side in the radial direction.

For example, the die-casting technique disclosed in Reference 1 needs a complex and elaborate mechanism including bearings and the like so that the cores may rotate without resistance when the cores are removed from the die-cast impeller. Additionally, a mechanism to position each of the cores at a predetermined angle before the injection-forming process is required to the die-casting technique disclosed in Reference 1; therefore, the manufacturing cost of a die-casting device may increase.

Moreover, according to the die-casting technique disclosed in Reference 1, the aforementioned cam plate needs to be rotated about the rotational axle in order to remove the plural cores in conjunction with one another from the die-cast impeller. Accordingly, the cam plate may not serve as a drive source for moving a movable die covering upper ends of the blades to an upper side of the impeller after the impeller is formed by die casting. In addition, according to the die-casting technique disclosed in Reference 1, the cores are moved toward the outward side in the radial direction; therefore, a large space may be required in the radial direction of the impeller.

A need thus exists for a molding device and a molding method for forming an impeller, which are not susceptible to the drawbacks mentioned above.

SUMMARY

According to an aspect of this disclosure, a molding method for forming an impeller including a main body and a plurality of blades arranged at one surface of the main body to circumferentially adjoin one another, each of the blades being inclined at different inclination angles at radially outward and inward sides toward one side in a rotating direction of the impeller, the molding method includes a mold clamping process including a first mold for forming one side of the blades, a second mold firmly clamped with the first mold to face the first mold, and a core arranged at the first mold relative to the blades, the mold clamping process clamping the first mold to the second mold in a state where the core is arranged between the first mold and the second mold, an injecting process injecting resin in a cavity obtained by the mold clamping process, and a mold removing process including the steps of releasing at least the first mold from the clamped state obtained by the mold clamping process to generate an opened portion in the first mold after the resin is hardened, rotating the core about a rotational axis toward the opened portion of the first mold, the rotational axis extending from the radially outward side to the radially inward side of the impeller, and separating the core from the resin-molded impeller.

According to another aspect of this disclosure, a molding device for forming an impeller including a main body and a plurality of blades arranged at one surface of the main body to circumferentially adjoin one another, each of the blades being inclined at different inclination angles at radially outward and inward sides toward one side in a rotating direction of the impeller, the molding device includes a first mold forming one side of the blades, a second mold firmly clamed with the first mold to face the first mold, a core arranged at the first mold relative to the blades and being rotatable about a rotational axis, the rotational axis extending from the radially outward side to the radially inward side of the impeller, a resin injecting mechanism injecting resin in a cavity formed by the first mold, the second mold, and the core, and a mold removing mechanism releasing at least the first mold clamped with the second mold therefrom to form an opened portion in the first mold after the resin is hardened, rotating the core about the rotational axis toward the opened portion of the first mold, and separating the core from the resin-molded impeller.

DETAILED DESCRIPTION

An embodiment of this disclosure will be described as follows with reference to illustrations of the attached drawings. A molding device80for forming an impeller50by resin injection molding is illustrated in each ofFIGS. 1A and 1B.FIGS. 1A and 1Billustrate first and second states, respectively, of a main portion of the molding device80. The impeller50is used for a water pump such as a coolant water circulating pump and the like.

[Configuration of the Molding Device]

As illustrated inFIGS. 1A and 1B, the impeller50includes a cylindrical main body51and eight blades52. The blades52are integrally formed with an inner surface (one surface) of the main body51. The blades52arranged at the inner surface of the main body51circumferentially adjoin one another. As illustrated inFIGS. 8A,8B, and8C, a flange portion518is integrally formed with a lower end of a cylindrical portion51A of the main body51so as to extend outward in a radial direction of the impeller50. An inner circumferential surface of the cylindrical portion51A is connected to a lower surface of the flange portion518by an annular smoothly curved surface surrounding a rotational axle X1of the impeller50. Each of the blades52extends from a portion of the inner circumferential surface of the cylindrical portion51A via the annular smoothly curved surface to an inner circumferential peripheral portion of the lower surface of the flange portion51B. In particular, the blade52is inclined from the annular smoothly curved surface toward one side in a circumferential direction (rotating direction) of the impeller50relative to the rotational axle X1.

As illustrated inFIG. 3, the molding device80includes a base1having a flat plated shape, wall portions2vertically formed at an upper surface of the base1so as to extend upward therefrom, and a tabular member3arranged so as to connect respective upper ends of the wall portions2. Each of the wall portions2has a rectangular shape when seen in planar view. As illustrated inFIG. 5, a first outer mold3A for forming the main body51of the impeller50by injection molding is arranged at a center portion of an upper surface of the tabular member3. A boss portion for forming a room penetrating through a central portion of the impeller50is arranged at the first outer mold3A so as to protrude upward along the rotational axle X1. The first outer mold3A corresponds to a first mold for forming a lower side (one side) of the blades52.

An injection mold for forming the impeller50by injection molding includes the first outer mold3A, a second outer mold4corresponding to a second mold and arranged at an upper surface of the first outer mold3A so as to face the first outer mold3A along a vertical direction seen inFIG. 4, and cores5for forming blade surfaces52A (seeFIGS. 6,8A,8B, and8C) of the blade52. A cavity is formed by the first outer mold3A, the second outer mold4, and the cores50. In particular, resin is injected into the cavity; thereby, the cores5form the inclined blade surfaces52A.

The second outer mold4is movably driven by a driving device between a molding position where the second outer mold4is positioned in a firm contact manner with the upper surface of the first outer mold3A (seeFIG. 4) and a mold removed position where the second outer mold4is removed or detached upward from the first outer mold3A (seeFIG. 5). A mechanism to move the cores5between the molding position and the mold removed position will be described below.

As illustrated inFIG. 3, a drive shaft60vertically reciprocating by means of a force such as hydraulic pressure includes a first movable plate6and a second movable plate7. The first movable plate6and the second movable late7constitute portions of first and second support members, respectively. The first movable plate6is arranged at an upper end of the drive shaft60between the base1and the tabular member3. The second movable plate7is arranged at an upper surface of the first movable plate6between the base1and the tabular member3. Eight extrusion pins15for extruding the resin-molded impeller50upward from the first outer mold3A are vertically arranged at an upper surface of the second movable plate7. Each of the extrusion pins15serves as a support device for supporting the resin-molded impeller50. At least a pair of compression springs20is arranged between the tabular member3and the second movable plate7. Each of the compression springs20exerts a biasing force by which the second movable plate7is moved downward toward the first movable plate6.

Eight auxiliary rods9vertically extending (each of the auxiliary rods9constitutes a portion of the first support member) are arranged on the upper surface of the first movable plate6at substantially equal intervals in an annular form around the rotational axle X1. Eight main rods10(each of the main rods10constitutes a portion of the second support member) vertically extending are arranged on the upper surface of the second movable plate7at substantially equal intervals in an annular form around the rotational axle X1. The auxiliary rods9and the main rods10are arranged on the same circle in an alternating manner. In addition, plural guide rods8are vertically arranged on the upper surface of the second movable plate7and through-holes through which the guide rods8are vertically movably guided are formed in the tabular member3. The auxiliary rods9, the main rods10, and the extrusion pins15are reachable to an upper side of the first outer mold3A through respective opening guide portions formed in the tabular member3.

As illustrated inFIG. 2, rotary links12serving as rotary members and having H-shapes in planar view are supported by and arranged between respective upper ends (respective ends) of the auxiliary rods9and the main rods10adjoining one another. Each of the rotary links12includes radially outward and radially inward link portions12A and12B arranged at radially outward and inward sides with respect to the rotational axle X1, and an intermediate portion12C connecting the radially outward link portion12A to the radially inward link portion12B. The auxiliary rod9and the main rod10are sandwiched between the radially outward link portion12A and the radially inward link portion12B that have rectangular shapes when seen in side view.

The rotary link12includes first and second ends in a longitudinal direction (circumferential direction). As illustrated inFIGS. 1A and 1B, the rotary link12is supported to the auxiliary rod9by a slidable pivot pin13B (first pivot portion) supported slidably in the longitudinal direction by an elongated bore12H formed in the first end of the rotary link12. Further, the rotary link12is supported to the main rod10by a fixed pivot pin13A (second pivot portion) fixed to the second end of the rotary link12so as not to move. When the second outer mold4is in the molding position in which the first movable plate6is arranged on the upper surface of the base1, the elongated bore12H extends substantially horizontally along the longitudinal direction of the movable link12so that the orientation of the rotary link12may vary in a state where the auxiliary rod9and the main rod10are maintained in a parallel position to each other.

As illustrated inFIG. 7A, the cores5described above are attached to ends of support arms14extending perpendicularly from radially inward surfaces of the respective radially inward link portions12B toward a portion being in the vicinity of the rotational axle X1. That is, the cores5are supported by the rotary links12from the radially outward side of the rotary links12. As illustrated inFIGS. 7A and 7B, each of the cores5includes a base end portion5A and a tip end portion5B. The base end portion5A linearly extends from each of the support arms14toward the portion being in the vicinity of the rotational axle X1. The tip end portion5B extends from the base end portion5A so as to be curved along the inner circumferential surface of the cylindrical portion51A of the impeller50in a clockwise fashion as seen in a planar view ofFIG. 7A. The base end portions5A of the cores5form the blades52and a portion at a radially outward side of the lower surface of the flange portion51B of the main body51. The tip end portions5B of the cores5form the blades52and a portion extending in a range defined between the inner circumferential surface of the cylindrical portion51A and a portion at a radially inward side of the lower surface of the flange portion51B. Protrusions are arranged at respective lower surfaces of the tip end portions5B so as to be engaged with the first outer mold3A. The protrusions of the tip end portions5B inhibit the tip end portions5B from being elastically deformed by a pressure of the resin during the resin injection molding process of the impeller5.

As illustrated inFIG. 8B, the support arm14is arranged closer to the elongated bore12H than to an intermediate portion of the rotary link12in the circumferential direction of the rotary link12. The core5extends obliquely upward from the end of the support arm14toward the main rod10; therefore, the tip end portion5B of the core5is positioned in the vicinity of an intermediate position between the elongated bore12H and the fixed pivot pin13A so as to be above the fixed pivot pin13A. In particular, upper edges of the tip end portions5B of the cores5extend along a circular arc defined by inner ends of central axes of the fixed pivot pins13A in the radial direction of the impeller50(each of the central axes corresponds to a rotational axis X3of the core5).

As illustrated inFIG. 1A, the plural blades52and the radially inward end portions5B of the plural cores5are arranged so as to adjoin one another in a substantially annular form around the rotational axle X1of the impeller50. Meanwhile, the plural blades52and the radially inward end portions5B (the plural cores5) are substantially linearly laid out in a horizontal direction so as to be easily seen inFIGS. 8A,8B and8C,

In addition, as illustrated inFIG. 6, at least a pair of lever devices16(speed increasing mechanisms) being rotatable about respective central axes X2is supported by a portion at an outer circumferential side of the first movable plate6. The central axes X2of the lever devices16are arranged along a circumferential direction of the first movable plate6. Each of the lever devices16includes a radially outward arm portion16A extending radially outwardly from the central axis X2and a radially inward arm portion16B extending radially inwardly from the central axis X2. A radially outward roller17A (first end portion) is rotatably supported by an end of the radially outward arm portion16A and a radially inward roller17B (second end portion) is rotatably supported by an end of the radially inward arm portion16B. The radially inward arm portion16B is designed to be substantially longer than the radially outward arm portion16A. Contact surfaces2A facing downward as seen inFIG. 6and constituting portions of a main body of the molding device80are formed at inner surfaces of the wall portions2. The contact surfaces2A are contactable with the radially outward rollers17A in accordance with the rotation of the lever devices16about the central axes X2.

[Molding Method for Forming the Impeller]

First, the second outer mold4is firmly clamped with the upper surface of the first outer mold3A in a state where the first movable plate6is positioned on the upper surface of the base1as illustrated inFIG. 4. In such state, the substantially annular cavity is formed between the second outer mold4and an outer circumferential side of the boss portion of the first outer mold3A.

In the condition that the second outer mold4is firmly clamped with the upper surface of the first outer mold3A, the orientation of each of the rotary links12is maintained to be horizontal as illustrated inFIG. 7A. In addition, the eight cores5are arranged in the annular form along the outer circumferential side of the boss portion of the first outer mold3A. At this time, as illustrated inFIG. 8A, the cores5are slightly inclined relative to a horizontal surface and are in contact with both the upper surface of the first outer mold3A and a lower surface of the second outer mold4. The resin is injected from a resin injection gate into the cavity formed by the second outer mold4, the cores5, and the first outer mold3A that includes the boss portion (such process corresponds to a resin injection process).

A mold removing process of the molding method according to the embodiment will be explained as follows. In a first step of the mold removing process, after the resin is hardened, the second outer mold4is removed upward from the first outer mold3A. Then, the first movable plate6is moved linearly upward (toward a first direction in the vertical direction seen inFIG. 4) by the drive shaft60at a predetermined speed; thereafter, the radially outward rollers17A of the lever devices16start making contact with the contact surfaces2A of the wall portions2as illustrated inFIG. 5. A process right before the radially outward rollers17A make contact with the contact surfaces2A will be referred to as a second step of the mold removing process. In the second step, the first movable plate6and the second movable plate7move upward together with the drive shaft60, therefore moving all of the eight extrusion pins15, the eight auxiliary rods9, and the eight main rods10upward in the same way as the drive shaft60moves upward.

As a result, the impeller50corresponding to the resin-molded impeller is lifted upward from the first outer mold3A by the eight extrusion pins15. At this time, the rotary links12supported by the auxiliary rods9and the main rods10simultaneously move upward while being maintained in the horizontal position. Therefore, the cores5move upward together with the resin-molded impeller50while being maintained in the inclined state established when the resin is injected in the cavity. As a result, as illustrated inFIGS. 5 and 8Bshowing a final stage of the second step, the first outer mold3A is released from the second outer mold4so as to have an opened portion facing the upward direction (a process from the aforementioned first step to the aforementioned second step corresponds to a first movement phase of the mold removing process of the molding method according to the embodiment).

After the radially outward rollers17A start making contact with the contact surfaces2A as described above, the drive shaft60moves the first movable plate6further upward. Then, the first movable plate6moves upward to a top dead point in accordance with the rotation of the lever devices16as illustrated inFIG. 6. A process from the time when the radially outward rollers17A start making contact with the contact surfaces2A to the time when the first movable plate6is moved upward to the top dead point will be referred to as a third step of the mold removing process.

In the third step corresponding to a second movement phase of the mold removing process of the molding method according to the embodiment, the second movable plate7is moved upward to the upper side of the first movable plate6by the radially inward arm portions16B of the lever devices16against the biasing forces of the compression springs20in accordance with the rotation of the lever devices16. Consequently, the extrusion pins15and the main rods10arranged at the second movable plate7move upward at a slightly high speed. On the other hand, the auxiliary rods9arranged at the first movable plate6move upward at a speed that is slower than the speed at which the extrusion pins15and the main rods10move upward. As a result, as illustrated inFIG. 6the rotary links12are rotated downward relative to the main rods10about the rotational axes X3of the cores5(the aforementioned rotational axes X3correspond to the central axes of the fixed pivot pins13A). Each ofFIGS. 6,7B, and8C illustrates a final stage of the third step.

As described above, the cores5supported by the support arms14and positioned at a radially inward side of the rotary links12are removed obliquely downward from the blade surfaces52A (upper blade surfaces) and lower blade surfaces of the blades52of the resin-molded blade50toward the aforementioned opened portion of the first outer mold3A in accordance with the simple rotation of the rotary links12. Thus, the molding device80according to the embodiment does not require a mechanism provided with bearings and the like for allowing the cores5to rotate without resistance about the rotational axes X3extending along a direction in which the cores5are separated from the resin-molded impeller50. Accordingly, the molding device80may be manufactured at low cost. In addition, the upper and lower blade surfaces that configure portions of each of the blades52are inclined at different inclination angles at radially outward and inward sides toward one side relative to the rotational axle X1in the circumferential direction of the impeller50. Shapes of the upper and lower blade surfaces of the blade52and each of the rotational axes X3are designed so that portions of each of the cores5may initially trace circular arcs along the inclinations of the upper and lower blade surfaces at arbitrary points between the radially outward side and the inward side of the impeller50when the cores5rotate about the rotational axes X3in the third step. Consequently, the cores5are smoothly separated from the upper and lower blade surfaces of the blades52in the third step.

After the cores5are completely separated from the first outer mold3A as described above, the resin-molded impeller50positioned on respective upper ends of the extrusion pins15may be detached therefrom. Afterward, as the first movable plate6is continuously moved downward by the drive shaft60, the second movable plate7biased downward by the compression springs20is moved downward by the function of the lever devices16at a speed higher than a moving speed of the first movable plate6in a state where the radially outward rollers17A are being maintained in contact with the contact surfaces2A (such downward movement of the first movable plate6and the second movable plate7is performed in reverse order relative to the order from the second step to the third step). As a result, the rotary links12are returned to the horizontal position. Thereafter, the first movable plate6and the second movable plate7are moved downward at the substantially same speed by the drive shaft60from the time when the radially outward rollers17A start separating from the contact surfaces2A. As s result, the cores5are returned to the molding position in which the cores5are in contact with the first outer mold3A. At this time, the second outer mold4is firmly clamped with the first outer mold3A; thereby, the resin may be again injected into the injection mold.

The embodiment of the disclosure may be modified as follows. According to the embodiment, the elongated bores12H are formed in the rotary links12. Alternatively, elongated bores may be formed in the auxiliary rods9or the auxiliary rods9may be elastically deformed so that the respective upper ends of the auxiliary rods9are moved close to the respective upper ends of the main rods10.

Further, the embodiment of the disclosure may be modified as follows. The molding method according to the embodiment is adapted to the impeller50configured so that the blades52are arranged at an inner side of the main body51, that is, the molding method according to the embodiment is adapted to the impeller50corresponding to an impeller including inner blades. Alternatively, the molding method according to the embodiment may be applied to an impeller including outer blades arranged at an outer side of a main body of the impeller.

Furthermore, the embodiment of the disclosure may be modified as follows. According to the embodiment, the central axes of the fixed pivot pins13A and the rotational axes X3of the cores5extend along a flat surface (horizontal surface) that is perpendicular to the rotational axle X1of the impeller50. Alternatively, the central axes of the fixed pivot pins13A and the rotational axes X3of the cores5may be inclined obliquely upward or obliquely downward relative to the aforementioned fiat surface.

The molding method for forming the impeller50and the molding device80for the same according to the embodiment of the disclosure may be utilized as a technique to form an impeller including a main body and plural blades that are arranged at the main body so as to circumferentially adjoin one another.

As described above, according to the aforementioned embodiment, the molding method for forming the impeller50having the main body51and the plural blades52arranged at the inner surface of the main body51to circumferentially adjoin one another, each of the blades52being inclined at the different inclination angles at the radially outward side and the inward side toward the one side in the rotating direction (circumferential direction) of the impeller50, the molding method including the mold clamping process having the first outer mold3A for forming the lower side of the blades52, the second outer mold4firmly clamped with the first outer mold3A to face the first outer mold3A, and the cores5arranged at the first outer mold3A relative to the blades52, the mold clamping process clamping the first outer mold3A to the second outer mold4in a state where the cores5are arranged between the first outer mold3A and the second outer mold4, the injecting process injecting the resin in the cavity obtained by the mold clamping process, and the mold removing process including the steps of releasing at least the first outer mold3A from the clamped state obtained by the mold clamping process to generate the opened portion in the first outer mold3A after the resin is hardened, rotating the cores5about the rotational axes X3toward the opened portion of the first outer mold3A, the rotational axes X3extending from the radially outward side to the radially inward side of the impeller50, and separating the cores5from the resin-molded impeller50.

According to the molding method of the aforementioned embodiment, the cores5are rotated about the rotational axes X3extending along the radial direction from the radially outward side to the radially inward side of the impeller50, thereby separating the cores5from the resin-molded impeller50. As a result, the mechanism to remove the cores5from the resin-molded impeller50may be simply configured. In addition, such mechanism does not require a large space in the radial direction of the impeller50, compared to the known mechanism to separate the cores toward the outward side in the radial direction of the die-cast impeller.

According to the aforementioned embodiment, the mold removing process includes the first movement phase for separating the resin-molded impeller50in contact with the cores5from the first outer mold3A along the rotational axle X1of the impeller50, and the second movement phase for rotating the cores5about the rotational axes X3in the middle of the first movement phase.

According to the molding method of the aforementioned embodiment, the cores5being in contact with the resin-molded impeller50are firstly moved upward along the rotational axle X1in the first movement phase. Accordingly, the opened portion into which the cores5separated from the resin-molded impeller50are moved may be obtained in the upward direction. Next, the cores5are rotated about the rotational axes X3in a state where the resin-molded impeller50is being moved further upward. Consequently, the cores5are appropriately separated from the resin-molded impeller50so as to be moved into the opened portion.

According to the aforementioned embodiment, the molding device80for forming the impeller50including the main body51and the plural blades52arranged at the inner surface of the main body51to circumferentially adjoin one another, each of the blades52being inclined at the different inclination angles at the radially outward side and the inward side toward the one side in the rotating direction of the impeller50, the molding device80including the first outer mold3A forming the lower side of the blades52, the second outer mold4firmly clamed with the first outer mold3A to face the first outer mold3A, the cores5arranged at the first outer mold3A relative to the blades52and being rotatable about the rotational axes X3, the rotational axes X3extending from the radially outward side to the radially inward side of the impeller50, the resin injecting mechanism injecting the resin in the cavity formed by the first outer mold3A, the second outer mold4, and the cores5, and the mold removing mechanism releasing at least the first outer mold3A clamped with the second outer mold4therefrom to form the opened portion in the first outer mold3A after the resin is hardened, rotating the cores5about the rotational axes X3toward the opened portion of the first outer mold3A, and separating the cores5from the resin-molded impeller50.

As described above, according to the molding device80of the aforementioned embodiment, the cores5are rotated about the rotational axes X3extending along the radial direction from the radially outward side to the radially inward side of the impeller50, thereby separating the cores5from the resin-molded impeller50. As a result, the mechanism to remove the cores5from the resin-molded impeller50may be simply configured. In addition, such mechanism does not require the large space in the radial direction of the impeller50, compared to the known mechanism to separate the cores toward the outward side in the radial direction of the die-cast impeller.

According to the aforementioned embodiment, the resin injecting mechanism includes the extrusion pins15arranged at the lower side of the resin-molded impeller50to move the resin-molded impeller50toward the upward direction in which the resin-molded impeller50is separated from the first outer mold3A along the rotational axle X1of the impeller50, and the rotary links12supporting the cores5from the radially outward side of the impeller50and rotating the cores5about the rotational axes X3in the middle of the movement of the resin-molded impeller50by the extrusion pins15toward the upward direction.

According to the molding device80of the embodiment, until the middle of the upward movement of the resin-molded impeller50by the extrusion pins15, the rotary links12supporting the cores5move upward together with the resin-molded impeller50while being maintained in the horizontal orientation obtained when the resin is injected in the cavity. Accordingly, the first outer mold3A forming the lower side of the blades52is released from the clamped state so as to have the opened portion facing the upward direction; therefore, the opened portion in which the cores5separated from the resin-molded impeller50are moved may be obtained. Next, the rotary links12rotate the cores5about the rotational axes X3from the middle of the upward movement of the resin-molded impeller50by the extrusion pins15. As a result, the cores5are separated from the resin-molded impeller50. That is, according to the molding device80of the embodiment, the upward movement of the resin-molded impeller50by the extrusion pins15may be performed simultaneously with the rotation of the cores5about the rotational axes X3, thereby increasing efficiency of the molding process of the impeller50.

According to the aforementioned embodiment, the molding device80further includes the speed increasing mechanism16. Each of the rotary links12includes the slidable pivot pin13B slidably and pivotally supported by the auxiliary rod9being movable toward the upward direction, and the fixed pivot pin13A pivotally supported by the main rod10integrally moving with the resin-molded impeller50and being movable relative to the auxiliary rod9. The speed increasing mechanism16allows the second movable plate7to move at the speed higher than the moving speed of the first movable plate6toward the upward direction to rotate the rotary links12.

According to the configuration of the molding device80of the aforementioned embodiment, the first movable plate6and the second movable plate7are moved toward the same direction to each other so as to move at the different speeds with respect to each other, thereby rotating the rotary links12. As a result, the molding device80having the simple configuration may be easily obtained. In addition, according to the configuration of the molding device80of the aforementioned embodiment, the second movable plate7may move at the speed higher than the moving speed of the first movable plate6in a state where the moving speed of the first movable plate6is maintained. Therefore, the first outer mold3A may be inhibited from being cooled and the molding time of the impeller50(for example, a time required to separate the first outer mold3A from the resin-molded impeller50) may be reduced.

According to the aforementioned embodiment, the speed increasing mechanism16includes the lever devices16pivotally supported by the first movable plate6. In a case where the first movable plate6moves linearly toward the upward direction, the lever devices16rotate to bring the radially outward rollers17A of the lever devices16into contact with the contact surfaces2A of the main body of the molding device80to accelerate the movement of the second movable plate7toward the upward direction by the radially inward rollers176of the lever devices16.

According to the configuration of the molding device80of the aforementioned embodiment, while the first movable plate6is being moved linearly upward, the second movable plate7is automatically moved at the speed higher than the moving speed of the first movable plate6by the radially inward rollers17B of the lever devices16. Thus, the first movable plate6is driven by the driven shaft60; thereby, the second movable plate7is moved upward in conjunction with the first movable plate6. As a result, the speed increasing mechanism may be reasonably configured.

According to the aforementioned embodiment, the first support member includes the first movable plate6reciprocating along the rotational axle X1and the plural auxiliary rods9vertically arranged at the first movable plate6in the annular form, and the second support member includes the second movable plate7supported by the first movable plate6so as to move relative thereto along the rotational axle X1and the plural main rods10vertically arranged at the second movable plate7in the annular form. Each of the rotary links12is pivotally arranged between the upper end of each of the auxiliary rods9and the upper end of each of the main rods10, the auxiliary rods9and the main rods10adjoining one another in an alternating manner.

According to the configuration of the molding device80of the aforementioned embodiment, the same number of auxiliary rods9as the blades52and the same number of main rods10as the blades52are arranged at the first movable plate6and the second movable plate7, respectively. Therefore, the required number of the cores5for forming the plural blades52may be moved in conjunction with one another between the molding position and the mold removed position in which the cores5are separated from the resin-molded impeller50.