Rotary blade molding method, rotary blade molding die and rotary blade molded by the same

Abstract

A rotary blade molding method, a rotary blade molding die and a rotary blade molded thereby are disclosed. A cavity (79) for molding an impeller (31) is formed between a fixed-side die plate (59) and a movable-side die plate (75). The movable-side die plate (75) has a plurality of outer through holes (81) formed in spaced relation to each other in the peripheral direction on the inner peripheral surface of the cavity (79) and extending in the direction along which the fixed-side die plate (59) and the movable-side die plate (75) move away from or toward each other. Outer ejector pins (83) are removably inserted into the outer through holes (81), respectively. By changing the length of the outer ejector pins (83), the axial position of the forward end surface of each outer ejector pin (83) with respect to the inner peripheral surface of the cavity (79) is changed, so that the thickness of a molded product is changed thereby to adjust the balance of the impeller (31) around the axis thereof. As a result, the unbalance of the rotary blade can be adjusted by an inexpensive and simple method.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing an injection molding die according to an embodiment of the invention.

FIG. 2A is a front view showing an impeller molded with the injection molding die shown in FIG. 1.

FIG. 2B is a view of the part indicated by arrow B-B in FIG. 2A.

FIG. 2C is a sectional view taken in line C-C in FIG. 2A.

FIG. 3 is a sectional view showing a vortex electric air pump using, for example, the impeller shown in FIG. 2A.

Claims

1. A method of molding a rotary blade: wherein a cavity (79) for molding a rotary blade (31) having an axis in the direction along which a pair of dies (59, 75) are moved away from and toward each other is formed between the dies (59, 75);wherein a plurality of holes (63, 81, 87) opening to the inner peripheral surface of the cavity (79) in peripherally spaced relation with each other and extending in the direction along which the dies (59, 75) are moved away from or toward each other are formed on at least one of the dies (59, 75);wherein ejector pins (83, 89) are removably inserted in the plurality of the holes (63, 81, 87), respectively; andwherein the thickness of a molded product is changed by changing the length of the ejector pins (83, 89) inserted into the holes and thus changing the axial position of the forward end surfaces of the ejector pins (83, 89) with respect to the inner peripheral surface of the cavity (79) thereby to adjust the balance of the rotary blade (31) around the axis thereof.

2. The molding method according to claim 1, wherein at least three ejector pins (83, 89) are arranged equidistantly along the peripheral direction.

3. A rotary blade molded by the rotary blade molding method as set forth in claim 1.

4. A method of molding a rotary blade: wherein a cavity, (79) for molding a rotary blade (31) having an axis in the direction along which a pair of dies (59, 75) are moved away from and toward each other is formed between the dies (59, 75);wherein a plurality of holes (63, 81, 87) opening to the inner peripheral surface of the cavity (79) in peripherally spaced relation with each other and extending in the direction along which the dies (59, 75) are moved away from or toward each other are formed on at least one of the dies (59, 75);wherein gate bushings (65) are removably inserted in the plurality of the holes (63, 81, 87), respectively; andwherein the thickness of a molded product is changed by changing the length of the gate bushings (65) inserted into the holes and thus changing the axial position of the forward end surfaces of the gate bushings (65) with respect to the inner peripheral surface of the cavity (79) thereby to adjust the balance of the rotary blade around the axis thereof.

5. The molding method according to claim 4, wherein at least three gate bushings (65) are arranged equidistantly along the peripheral direction.

6. A rotary blade molded by the rotary blade molding method as set forth in claim 4.

7. A rotary blade molding die having a cavity (79) formed between the dies (59, 75), for molding a rotary blade (31) having an axis in the direction along which a pair of dies (59, 75) are moved away from and toward each other; wherein a plurality of holes (63, 81, 87) opening in the peripheral direction-of the cavity (79) in spaced relation with each other and extending in the direction along which the dies (59, 75) are moved away from or toward each other are formed on at least one of the dies (59, 75);wherein ejector pins (83, 89) are removably inserted in the plurality of the holes (63, 81, 87), respectively; andwherein the thickness of a molded product is changed by changing the length of the ejector pins (83, 89) inserted into the holes (63, 81, 87) and thus changing the axial position of the forward end surfaces of the ejector pins (83, 89) with respect to the inner peripheral surface of the cavity (79) thereby to adjust the balance of the resulting rotary blade (31) around the axis thereof.

8. The molding die according to claim 7, wherein at least three ejector pins (83, 89) are arranged equidistantly in the peripheral direction.

9. A rotary blade molded by the rotary blade molding die as set forth in claim 7.

10. A rotary blade molding die having a cavity (79) formed between the dies (59, 75), for molding a rotary blade (31) having an axis in the direction along which a pair of dies (59, 75) are moved away from or toward each other; wherein a plurality of holes (63, 81, 87) opening in the peripheral direction of the cavity (79) in spaced relation with each other and extending in the direction along which the dies (59, 75) are moved away from or toward each other are formed on at least one of the dies (59, 75);wherein gate bushings (65) are removably inserted in the plurality of the holes (63, 81, 87), respectively; andwherein the thickness of a molded product is changed by changing the length of the gate bushings (65) inserted into the holes (63, 81, 87) and thus changing the axial position of the forward end surfaces of the gate bushings (65) with respect to the inner peripheral surface of the cavity (79) thereby to adjust the balance of the resulting rotary blade (31) around the axis thereof.

11. The molding die according to claim 10, wherein at least three gate bushings (65) are arranged equidistantly along the peripheral direction.

12. A rotary blade molded by the rotary blade molding die as set forth in claim 10.