KR100411916B1 - Method for injection molding a propeller fan - Google Patents

Abstract

In the method of injection-molding a plastic propeller fan using the fixed side mold and a movable side mold, a movable core is provided in the part corresponding to the thick part of the wing part of a propeller fan, After injecting a certain amount of plastic raw material into the mold space wing space of the propeller fan formed of the movable mold and the movable core, the movable core is extruded inside the mold space, and then the movable core forms a wing space. A propeller fan is formed by returning to a normal position of a mold shape.

Description

Injection molding method of propeller fan {METHOD FOR INJECTION MOLDING A PROPELLER FAN}

The present invention relates to an injection molding method of a propeller fan, and more particularly, to an injection molding method of a plastic propeller fan used for an air conditioner condenser cooling fan, a ventilation line, a vehicle radiator cooling fan, and the like.

Conventionally, as shown in FIG.3 and FIG.4 as a plastic propeller fan is known. 3 is a plan view of the fan, and FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3, that is, a wing shape.

Conventionally, this kind of propeller fan is used for condenser cooling fans for air conditioners, ventilation lines, car radiator cooling fans and the like, and is mainly made of plastic material.

Moreover, although the vane shape is made with a thin plate in many cases, in order to improve aerodynamic performance, application of the fan blade (wing | blade root part) which has a wing-shaped cross section as shown in FIG. 4 is effective. In this case, however, a thick section is formed in a part of the fan blade by the blade-shaped cross section.

Fig. 5 shows a conventional mold structure for injection molding a plastic propeller pan. In the drawings, reference numeral 1 denotes a mold having a fixed side mold 2 and a movable side mold 3. The mold space 8 of the fan which is a molded article is formed by the said fixed side metal mold | die 2 and the movable side metal mold | die 3. As shown in FIG. The fixed side mold 1 is provided with an injection control pin bush 6 for smoothly maintaining the movement of the injection port 4 and the injection control pin 5 of the molten plastic. The fixed side mold 2 and the movable side mold 3 are provided with injection control pins 5 of molten plastic that are movable in the direction of the arrow A. Moreover, the said movable side metal mold | die 3 is provided with the extrusion pin 7 for extruding the pan of a molded article from a metal mold | die. The extrusion pin 7 moves in the direction of the arrow B. FIG. Moreover, the movement of position movement is performed to the said movable side metal mold | die 3, the injection control pin 5, and the extrusion pin 7 by each drive source which is not shown, respectively.

However, in the case of a thick wing shape, since it is thin at the tip of the wing and thick at the center of the wing and at the root part, there are problems of weight increase, embrittlement, deterioration of moldability due to increase in cycle time, and cost increase in general injection molding methods. .

In addition, foam molding, blow molding, and the like may be used as a method for obtaining a thick molded article having a good thickness, but the shape accuracy is poor, and a uniform molded article is difficult to obtain due to a lack of strength and durability or a difference in shrinkage speed of the thick portion, and the fan is rotated. There was a problem that the amount of imbalance that contributes to vibration deteriorates.

An object of the present invention is to install a movable core at a portion corresponding to a thick portion of a wing of a propeller fan, and to provide a fixed amount of plastic in a wing space of a mold space of a propeller fan formed of the fixed side mold, the movable side mold and the movable core. After injecting the raw material, the movable core is extruded inside the mold space, and then the movable core is returned to a mold-shaped normal position forming the wing space to form a propeller fan, thereby forming The present invention provides a method for injection molding a propeller fan capable of obtaining a uniform molded product even when mass produced with a small mass difference and maintaining a small amount of unbalance which contributes to fan rotational vibration.

The present invention also provides a movable core at a portion corresponding to a thick portion of the wing of the propeller fan, and the inside of the wing space of the mold space of the propeller fan formed of the fixed side mold, the movable side mold and the movable core. After extruding the movable core, the plastic raw material is pressed and filled to fill the mold space, and then the movable core is returned to a mold-shaped normal position forming the wing space to form a propeller fan, thereby providing a uniform The present invention provides a method for injection molding a propeller fan capable of realizing securing a molded article and reducing an unbalance amount.

In the first embodiment, in the method of injection molding a plastic propeller fan by using a fixed side mold and a movable side mold, a movable core is provided at a portion corresponding to the thick portion of the wing of the propeller fan, and the fixed side mold After injecting a certain amount of plastic raw material into the wing space of the mold space of the propeller fan formed of the movable mold and the movable core, the movable core is extruded inside the mold space, and then the movable core is wing space The propeller fan is formed by returning to the normal position (pre-operation position) of the mold shape which forms a shape. Therefore, even if it mass-produces with the mass difference of a thick part and a thin part being small, a uniform molded article can be obtained and the propeller fan which can maintain the unbalance amount which contributes to fan rotation vibration is obtained.

Further, in the second embodiment, in the method of injection molding the plastic propeller fan by using the fixed side mold and the movable side mold, a movable core is provided at a portion corresponding to the thick portion of the wing of the propeller fan, and the fixed side mold And extruding the movable core inside the wing space of the mold space of the propeller fan formed of the movable side mold and the movable core, and filling the mold space with the injection of plastic raw material, and then the movable core is winged. A propeller fan is formed by returning to the normal position (pre-operation position) of the mold shape which forms a space. Therefore, similarly to the first embodiment, a propeller fan capable of realizing a uniform molded article and reducing an unbalance amount is obtained.

In the injection molding method of the propeller fan according to the first embodiment of the present invention, in the method of injection molding a plastic propeller fan by using a fixed side mold and a movable side mold, a portion corresponding to a thick portion of a wing of the propeller fan A movable core is installed in the mold space, and a predetermined amount of plastic raw material is injected into the wing space of the mold space of the propeller fan formed of the fixed side mold, the movable side mold and the movable core, and then the movable core is extruded inside the mold space. The propeller fan is then formed by returning the movable core to a mold-shaped normal position (pre-operation position) that forms the wing portion space, thereby forming a propeller fan.

The injection molding method of the propeller fan which concerns on the 2nd Example of this invention is a method of injection molding a plastic propeller fan using a fixed side mold | die and a movable side mold | die, Comprising: It corresponds to the part corresponding to the thick part of the wing part of a propeller fan. After installing the movable core and extruding the movable core inside the wing space of the mold space of the propeller fan formed of the fixed side mold, the movable side mold and the movable core, the plastic raw material is injected and injected to fill the mold space. After that, the movable core is returned to a mold-shaped regular position (pre-operation position) that forms a wing space, thereby forming a propeller fan.

1 is an explanatory diagram of a mold structure for injection molding a plastic propeller fan according to the present invention;

2 is a cross-sectional view taken along the line II-II of FIG. 1;

3 is a plan view of a propeller fan made of plastic,

4 is a cross-sectional view taken along the line IV-IV of FIG. 3;

5 is an explanatory view of a conventional mold structure for injection molding a plastic propeller fan.

Explanation of symbols for the main parts of the drawings

12: fixed side mold 13: movable side mold

14: movable core 17: bush

19: extrusion pin 31a: wing

Next, the injection molding method according to the present invention will be described in more detail.

In the present invention, the plastic raw material is mixed with a reinforcing plastic material (P1) containing long fibers, a plastic material (P2) containing a blowing agent in an ordinary plastic material, or a long fiber reinforced plastic. One plastic material P3 is exemplified. Here, in the case of the material P1, the internal restoring force by the long fibers is used, in the case of the material P2, the foaming force is used, and in the case of the material P3, both the restoring force and the foaming force are used. This is because it forms swelling tissue in the. Further, as the material P1, the fiber content contained in the thermoplastic resin pellets is 10% by weight to 80% by weight, the total length of the pellets is from 2mm to 100mm, and the fiber contained in the pellets is substantially the same as the pellets total length. As the material, a material containing the pellets in a state arranged in parallel with each other in the longitudinal direction (the direction of the entire length) of the pellets is preferable.

In this invention, it is preferable to perform shaping | molding by making a movable core contact only the thick part of the center of a wing | blade, without making a movable core contact around the wing | tip tip part and wing root part of the said propeller fan. In this case, the movable cores are not contacted around the wing tip and the wing roots in order to reduce internal expansion at these points, and contacting the movable cores only at the thick part in the center of the wing prevents internal expansion at these points. To increase.

EMBODIMENT OF THE INVENTION Hereinafter, the shaping | molding method of the propeller fan which concerns on the Example of this invention is demonstrated.

First, the mold structure which concerns on this invention for injection molding a plastic propeller pan is demonstrated using FIG. 1 and FIG. 1 is an overall view of the fan, and FIG. 2 is a sectional view taken along the line II-II of FIG. 1.

In the figure, reference numeral 11 denotes a mold having a fixed side mold 12, a movable side mold 13, and a movable core 14. Here, the movable core 14 is provided in the part corresponding to the thick part 31b of the blade part 31a of the propeller fan, and moves to the arrow A direction. A mold space 15 of a fan, which is a molded product, is formed by the fixed side mold 12, the movable side mold 13, and the movable core 14. The fixed side mold 11 is provided with an injection control pin bush 17 for smoothly maintaining the movement of the injection port 16 of the molten plastic and the injection control pin described later.

The fixed side mold 12 and the movable core 14 are provided with injection control pins 18 of molten plastic that are movable in the direction of the arrow B. Moreover, the said movable side metal mold | die 13 is provided with the extrusion pin 19 for extruding the pan of a molded article from a metal mold | die. This extrusion pin 19 moves in the direction of an arrow C. FIG. Moreover, the said movable side metal mold | die 13, the movable core 14, the injection control pin 18, and the extrusion pin 19 respectively control position movement by each drive source which is not shown in figure.

Moreover, the said movable core 14 arrange | positions in order to comprise a part of the outer edge of the metal mold | die space 15 in contact with the position of the thick part 31b of the blade part 31a of the metal mold | die space 15 of the fan shown in FIG. Moreover, it is set as the shape which does not contact the thin part 31c of the periphery of the wing part 31a, and the wing | root part root part periphery 31d which requires strength.

Next, the method of shape | molding a plastic propeller fan using the metal mold | die of the structure mentioned above is demonstrated.

(Example 1)

(1) First, the injection control pin 18 is driven to open and melted in the mold space 15 formed of the fixed side mold 12, the movable side mold 13, and the movable core 14 from the injection port 16. Plastic material was injected. Here, as the molten plastic, long fiber reinforced plastics including glass fibers having a length of 3 mm or more, that is, long fiber reinforced GFPP (trade name: Mostron L (GF30%)) manufactured by Idemitsu Petrochemical Co., Ltd., were used.

(2) Next, when the molten plastic material is almost filled in the mold space 15 of the fan, the injection control pin 18 is closed, and the movable core 14 is extruded toward the wing 31a side, and the mold The plastic material in the space 15 was compressed and pressed to the periphery in the mold space 15. Here, the molding machine is an injection molding machine manufactured by Mitsubishi Heavy Industries Co., Ltd. (450 tons of force for fastening the mold), and has a molding temperature of 250 ° C., a mold temperature of 60 ° C., an injection time of 5 seconds, and an injection filling rate of 90% for the cavity. After the injection, the movable core was advanced after the injection was finished, and the compression was filled.

(3) Then, after a certain time, the movable core 14 is returned to the original position of the blade 31a shape formation, and the inside of the wing is made by the spring back force of the long fiber contained in the plastic material. The inner core was expanded at and the movable core 14 was held at a predetermined position until the outline of the molded article was formed into a wing shape along the shape of the mold space 15.

(4) Next, as the temperature of the plastic material injected into the mold space 15 decreases over time, the movable side mold 13 and the movable core (at the time when the change of the blade shape due to expansion or foaming is fixed) 14) was separated from the stationary mold 12, and the extrusion pin 19 was driven to take out the pan, which is a molded product, from the mold 11. The molding cycle was 70 seconds.

In the first embodiment, first, molten plastic material is injected into the mold space 15 from the injection hole 16, and when the plastic material is almost filled in the mold space 15, the injection control pin 18 is closed and operated. The core 14 is extruded to the wing part 31a side, the plastic material in the metal mold | die space 15 is compressed, and it is conveyed to the peripheral part in the metal mold | die space 15. As shown in FIG. Then, after a certain time, the movable core 14 is returned to its original position in the shape of the blade portion 31a, and is internally expanded inside the blade by the spring force of the long fibers contained in the plastic material, thereby forming the outer edge of the molded article. The movable side mold 13 is held at a point where the movable core 14 is held at a predetermined position until it is formed in a wing shape along the shape of the mold space 15 and the change of the wing shape due to expansion or foaming is fixed. And the movable core 14 is isolate | separated from the fixed side metal mold | die 12, the extrusion pin 19 is driven, and the fan which is a molded article is taken out from the metal mold | die 11.

Therefore, the strength holding part of the thin part 31c of the periphery of the fan part 31a of the fan, and the strength part of the root part periphery 31d is possible to hold | maintain the intensity | strength which plastic raw material densely, and the thick part 31b of the center part It is possible to fill less plastic raw materials by internal expansion or foaming. As a result, the mass difference between the thick part and the thin part is small, so that even if it is mass-produced, a uniform molded product can be obtained, and the amount of unbalance that contributes to the fan rotation vibration can be kept small.

In fact, the product (fan) obtained in the same manner as in Example 1 has a product size of 400 mm and a product weight of 450 g. With respect to the mold shape, the amount of deformation of the obtained product (fan) is up to 1 mm, which is a product having extremely high dimensional accuracy. Obtained. In addition, the space | gap inside was produced by the restoring force (spring back) of long fiber.

In addition, as a comparative example, injection molding was performed using short fiber GFPP (GF30%) using the equipment of Example 1. However, resin temperature: 230 degreeC, mold temperature: 40 degreeC, injection time: 5 second, pressure holding time: 30 second, cooling time: 220 second, and the molding cycle were 280 second. As a result, the product weight was 600 g, and the deformation amount of the obtained product (fan) with respect to the mold shape was at most 10 mm, the dimensional accuracy was low, and calibration by the secondary process was necessary.

(Example 2)

After extruding the movable core 14 to the wing part 31a side like the said (2) of the said Example 1, the plastic material is filled and filled in the metal mold space 15 of a pan, and the injection control pin 18 is carried out. Was closed. Next, the plastic propeller fan was shape | molded through the process similar to said (3) and (4) of Example 1.

According to Example 2, the same effects as in Example 1 were obtained.

Moreover, in the said Example, although the case where long-fiber reinforced plastics containing glass fiber etc. which have a length of 3 mm or more was used as a plastic material, it is not limited to this, The plastic material which mixed foaming agent with the normal plastic material Or a plastic material in which a foaming agent is incorporated into the long fiber reinforced plastic.

In addition, in the said embodiment, although an internal space | gap arises by expansion, you may inject gas in this internal space for shape maintenance. In the above embodiment, the case in which the wing portion is inflated has been described. However, the present invention is not limited thereto, and the boss portion (hub) corresponding to the center of the fan may also be brought in contact with the movable core to core back, if necessary. . Here, the "core bag" refers to a method of forming a plastic material by contacting the movable core to inject the plastic material and then returning it to a normal position.

In the injection molding method of the present invention, the mass difference between the thick portion and the thin portion of the propeller fan can be reduced, so that a uniform molded product can be obtained even during mass production, and the amount of imbalance with respect to the fan rotation vibration can be kept low.

Claims (6)

In the method of injection-molding the propeller fan made of plastic using the fixed side mold 12 and the movable side mold 13, Installing a movable core 14 at a portion corresponding to the thick portion 31b of the wing portion 31a of the propeller fan; Injecting a predetermined amount of plastic raw material into the wing space of the mold space 15 of the propeller fan formed of the fixed side mold 12, the movable side mold 13, and the movable core 14; Extruding the movable core 14 inside the mold space; And returning the movable core 14 to a mold-shaped normal position forming a wing space to form a propeller fan. Injection molding method of propeller fan. The method of claim 1, The plastic raw material is any one of reinforcement plastics including long fibers, plastics having a blowing agent, or reinforcement plastics including both long fibers and blowing agents. Injection molding method of propeller fan. The method of claim 1, It is characterized in that molding is carried out by bringing the movable core 14 into contact only with the thick portion 31b at the center of the wing, without contacting the movable core 14 at the wing tip portion and the blade root portion 31d of the propeller fan. doing Injection molding method of propeller fan. In the method of injection-molding the propeller fan made of plastic using the fixed side mold 12 and the movable side mold 13, Installing a movable core 14 at a portion corresponding to the thick portion 31b of the wing portion 31a of the propeller fan; Extruding the movable core 14 inside the wing space of the mold space 15 of the propeller fan formed of the fixed side mold 12, the movable side mold 13, and the movable core 14; Filling and injecting the plastic raw material into the mold space 15; And returning the movable core 14 to a mold-shaped normal position forming a wing space to form a propeller fan. Injection molding method of propeller fan. The method of claim 4, wherein The plastic raw material is any one of reinforcement plastics including long fibers, plastics having a blowing agent, or reinforcement plastics including both long fibers and blowing agents. Injection molding method of propeller fan. The method of claim 4, wherein It is characterized in that molding is carried out by bringing the movable core 14 into contact only with the thick portion 31b at the center of the wing, without contacting the movable core 14 at the wing tip portion and the blade root portion 31d of the propeller fan. doing Injection molding method of propeller fan.