JPH0741631B2 - Manufacturing method of reflector for antenna - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a reflector for an antenna used for receiving satellite broadcasts and the like.

(Prior Art) In the above-mentioned parabolic antenna used for receiving satellite broadcasting, the reflector must have a predetermined strength and a radio wave reflection function, and also has a good weather resistance for outdoor installation. Sex is required.

Therefore, for example, in Japanese Patent Laid-Open No. 1-144704, an antenna body is installed in a mold, and a thin leaf body in which a weather-resistant film is adhered on a conductive metal sheet is used for the radio wave reflection made of the conductive sheet. There is disclosed a technique in which a parabolic antenna is manufactured by placing a layer such that the layer fits on a radio wave reflecting surface of an antenna body and integrating the antenna body and the thin leaf body by vacuum pressure forming.

According to this, the antenna reflection plate including the radio wave reflection layer and the weather resistant layer covering the radio wave reflection layer can be manufactured all at once by the vacuum pressure forming step.

However, in the above reflection plate manufacturing method, the antenna main body and the thin leaf body are first manufactured in separate steps, and then the both are integrated by the vacuum pressure forming, so that the number of steps is increased and the cost is increased. As the temperature rises, the manufacturing becomes complicated and there is a drawback that it is not efficient.

For this, the fixed mold is clamped to the movable mold with the thermoplastic resin film having the radio wave reflection layer and the weather resistant layer adsorbed on the cavity forming surface of the movable mold, It is conceivable to inject the molten resin into the cavity from the side to form the antenna main body with the molten resin, and at the same time, apply the resin film to the radio wave reflection surface. According to this method, it is not necessary to separately manufacture the antenna body, the manufacturing process of the reflector is simplified, and the cost is reduced.

(Problems to be solved by the invention) By the way, in the production of the reflector by the above-mentioned injection molding, the cavity forming surface of the movable die is a convex parabolic curved surface imitating the radio wave reflection surface of the reflector, and the movable die is The air between the resin film sent to the cavity and the cavity structure surface is evacuated and discharged, and the resin is injected while the resin film is adsorbed on the cavity structure surface, and the resin is heated by the heat and pressure of the injected resin. The film is deformed while being stretched so as to be completely adhered to the cavity forming surface, and in that state, the resin film A is applied to the surface of the resin molded product B which is the antenna body as shown in FIG. Become.

However, in the above-described reflector C, since the web E and the flange F (some of which have no flange are provided) are usually provided on the periphery of the radio wave reflection surface D from the viewpoint of the strength of the body, the resin film A is formed on the radio wave reflection surface D. However, according to the experiment, when the web E is wrapped with the resin film A by the above-mentioned injection molding, in the molded product, the wrinkles of the film A and the like are formed on the web E. It was found that the distortions G to G occurred and the product quality deteriorates.

The cause of this is that the resin film A is folded back at a stretch against the web E by the resin injection pressure, and that the portion of the film A that is the base point of the folding is not always constant, and the film A covered with the web E is It is difficult to absorb the slack evenly in the circumferential direction, large stress acts on the folded portion, and the stress distribution is not uniform in the circumferential direction, so the expansion and contraction of the film at each portion of the folded portion becomes uneven. Can be considered. This was particularly remarkable when the radio wave reflection layer of the resin film A was formed of a material having a relatively poor stretchability such as an ammonium sheet.

Therefore, in the present invention, in which a resin film is adhered to the surface of a resin molded product by injection molding of a resin, the film portion folded back to the resin molded product does not cause distortion such as wrinkles. An object is to provide a method for manufacturing a reflector for an antenna.

(Means for Solving the Problem) That is, the present invention conveys a thermoplastic resin film in which a radio wave reflection layer and a weather resistant layer are laminated on one surface of a film substrate between a fixed mold and a movable mold. After clamping the fixed die and the movable die, a molten resin is injected from the fixed die into a cavity formed between the two dies to form an antenna body having a web portion around the radio wave reflection surface. With
In a method for manufacturing an antenna reflector in which the resin film is adhered to the periphery of the antenna body, a film preforming die is bonded to the suction head with the film substrate side of the resin film being sucked by the suction head. Thus, by cutting the resin film into a circle having a size slightly larger than the shape of the radio wave reflection surface, and by pressing the die body of the preforming die against the suction head, the peripheral portion of the resin film after cutting is cut. A preforming step of bending the portion of the antenna body corresponding to the boundary between the radio wave reflection surface and the web in the bending direction of the web with respect to the radio wave reflection surface, and the preformed resin film can be moved while adsorbed by the adsorption head. The film transfer process of loading the film onto the front surface of the cavity forming surface of the mold, and bringing the suction head into pressure contact with the movable mold. A film setting step of holding the peripheral edge of the resin film between them and sucking the resin film to the movable mold by sucking air between the cavity forming surface and the resin film; It is characterized in that it comprises a resin molding step in which the movable mold and the fixed mold are clamped after being withdrawn from the front surface position, and molten resin is injected from the fixed mold into the cavity formed between the two molds.

(Operation) According to the above method, before carrying the thermoplastic resin film into the die, the resin film is cut out to a size larger than the radio wave reflection shape while being adsorbed by the adsorption head, and the preforming die By pressing the die body against the suction head, the portion corresponding to the boundary between the radio wave reflection surface of the antenna body and the web in the peripheral portion of the resin film after cutting is curved in the bending direction of the web with respect to the radio wave reflection surface. Therefore, the shape of the peripheral portion of the resin film is close to the final shape. Therefore, at the time of injection molding of the resin, the starting point of folding back is constant, and even for a resin film having poor elasticity, the peripheral edge of the resin film is adhered to the web portion evenly by the injection pressure, and the film folding back is performed. The stress acting on the part is small and uniform, the expansion and contraction of the film is constant in any part, and the wrinkle of the film does not occur in the web part of the product.

(Example) Next, the Example of this invention is described based on drawing.

FIG. 1 shows an injection molding die apparatus embodying the method of the present invention, in which a movable die 2 is disposed so as to be separable from and in contact with a fixed die 1, and at a position directly above both dies 1, 2. With the suction head 3 and the film preforming die 4 arranged, and the movable die 2 is separated from the fixed die 1, the suction head 3 can be moved up and down between a raised position shown by a solid line and a lowered position shown by a chain line. ing.

The suction head 3 sucks the thermoplastic resin film X described below in a raised state, cuts it into a predetermined shape in cooperation with the film preforming die 4, preforms the film X, and moves it after the preforming. The resin film X is carried in by descending to the front surface of the mold 2.

Here, as an example of the resin film X, as shown in FIG. 2, a base material sheet X ₁ made of a resin of the same material as the injection resin, for example, a polystyrene resin, an ammonium sheet, and an acrylic resin are used. It is conceivable that a sheet made of a resin or the like is laminated by adhesion, and the radio wave reflection layer X ₂ made of the above-mentioned ammonium sheet is used as an intermediate layer, and a weather resistant layer X ₃ is formed thereon by an acrylic resin sheet.
Further, depending on the thickness of the ammonium sheet, an ammonium sheet reinforcing layer such as a polyester sheet may be provided between the reflective layer X ₂ and the weather resistant layer X ₃ . However, as long as the method of the present invention described later can be applied, the resin film X
Is not limited to the above. For example, the weather resistant layer X ₃ and the reflective layer X _{2 made of the} above acrylic resin sheet.
On the other hand, a resin film having an adhesive layer instead of the base sheet X ₁ can be used as the resin film.

The suction head 3 is supported by an elevating table 5, and the elevating table 5 is connected with a piston rod 7 of a fluid pressure cylinder 6 whose upper end is connected to a fixing portion (not shown). The elevating table 5 is moved up and down by the expansion and contraction operation.

Further, the suction head 3 is configured to come into contact with and move away from the movable die 2 in a lowered state, so that the rods 8 and 8 connected to the back surface of the suction head 3 are laterally attached to the lifting table 5 as shown in FIG. In addition to being slidably supported, the lift table 5 is equipped with solenoids 9 and 9 for pushing and pulling these rods 8 and 8. The excitation head 3 contacts the movable die 2 by exciting the solenoids 9 and 9. The movable member 2 is moved in the direction and is returned to the direction in which it is separated from the movable mold 2 by the force of the spring members 10 and 10 when the excitation is released.

In addition, the film preforming die 4 described above is attached to the suction head 3.
A large number of small-diameter air holes 11 are formed on the film suction surface 3a facing the ...
11 are opened at equal pitches, and these ventilation holes 11 ... 11 are connected to an air flow path 12 formed inside the suction head, and an air hose 13 is connected to this air flow path 12. The air hose 13 is switched and connected to the vacuum pump 15 and the compressor 16 by a three-way switching valve 14. The vacuum pump 15 applies an air suction force to the adsorption head 3 via the air hose 13 to adsorb the resin film X to the adsorption head, and the compressor 16 sends compressed air to the adsorption head 3 to cause a film vacuum described later. Resin film X adsorbed during pressure molding
Is released from the suction head 3 by pressure. The film suction surface 3a is coated with Teflon in order to ensure good film releasability at the time of vacuum vacuum forming of the film.

Further, the film suction surface 3a of the suction head 3 is provided with
And a flat portion 18 that surrounds the convex base portion 17, and a peripheral portion of the convex base portion 17 is a curved portion 17a that is continuous with the flat portion 18.
Further, the outer corner portion of the flat portion 18 is used as an edge portion 19 for cutting the film.

In addition, in the suction head 3, a clamp plate is provided so as to surround the film suction surface 3a composed of the convex base portion 17 and the flat portion 18.
20 is attached, and this clamp plate 20 is a spring member 21, 21
Is always urged toward the film preforming die 4 side with respect to the suction surface 3a.

On the other hand, the film preforming die 4 is composed of a holder 22 and a die body 23 built in the holder 22. The holder 22 is supported by a support frame 24 via a fluid pressure cylinder 25A, and the holder 22 is Locating pin 26 on top of
Is projected. The mold body 23 is a fluid pressure cylinder 25B.
The mold main body 23 includes a film molding portion 27 that can be protruded and retracted from the holder 22 by the projection 22, and that is fitted with the convex base portion 17 of the suction head 3 and a film molding portion 28 that is in contact with the flat portion 18. An inner corner portion of the holder 22 that is formed by recessing in the front surface of the mold body 23 and surrounds the die body 23 serves as an edge portion 29 for cutting a film.

The film preforming die 4 is brought into and out of contact with the suction head 3 by the operation of the fluid pressure cylinders 25A and 25B. In preparation for this joining, the head 3 is raised to the suction head 3 side. At this time, the groove 30 that engages with the support frame 24
And a pin hole 31 into which the positioning pin 26 projects.

In the fixed die 1 and the movable die 2 described above, the fixed die 1 is a fixed platen.
32, the movable die 2 is attached to the movable plate 33, and the movable plate 33 is fixed to the fixed plate 32 by the fluid pressure cylinders 34, 34.
The movable mold 2 and the fixed mold 1 are moved by moving them away from each other.
And are opened and closed using a tie bar (not shown) as a guide. When the two dies 1 and 2 are joined, a parabolic antenna-shaped cavity is formed between the dies.

In the fixed mold 1 described above, as shown in FIG. 4, the cavity plate 35 is held by the support block 36, and the cavity plate 35 is surrounded by the mold matching surface 37 of the support block 36 and has a concave curved cavity forming surface 38. And a gate for resin injection is opened in the cavity forming surface 38, while a spool bush 39 provided in the support block 36 is formed.
The sprue 40 is communicated with the gate, whereby the molten resin supplied from the injection nozzle 41 to the sprue 40 is injected into the aforementioned cavity from the gate.

Further, on the cavity forming surface 38, the flange portion Yb (the first portion shown in FIG. 9) of the antenna body shown in FIG.
An annular recess 42 for forming a portion (corresponding to the flange F in FIG. 10) is formed.

In the movable mold 2, the cavity plate 43 is held by the support block 44, and the cavity plate 43
In addition, a convex curved cavity forming surface 45 facing the cavity forming surface 38 of the fixed mold 1 is formed. Further, the ring block 46 is fitted onto the cavity plate 43. On the other hand, a plurality of recesses 44a, 44a are formed on the back surface of the support block 44 at positions surrounding the cavity plate 43, and one ends of slide rods 47, 47 penetrating the support block 44 back and forth engage with these recesses 44a, 44a. Being these slide rods 4
With 7,47 being able to slide back and forth by a certain amount,
The other ends of these slide rods 47, 47 are connected to the ring block 46. In that case, spring members 47a, 47a are provided between the support block 44 and the ring block 46,
The ring block 46 is urged so as to project toward the fixed mold 1 side with respect to the cavity plate 43.

Further, a film suction portion 49 (in order to clarify the existence of this suction portion 49 is shown by a concave shape in FIG. 7 and FIG. 8 on the mold matching surface 48 surrounding the cavity plate 45 of the ring block 46). Is formed),
A concave portion 50 continuous with the film suction portion 49 is formed on the inner peripheral surface of the ring block 46, and the ring block 4 is resisted against the spring members 47a, 47a by clamping the fixed die 1 and the movable die 2 together.
When 6 is retracted, the recessed portion 50 is configured to be continuously connected to the peripheral portion of the cavity constituting surface 45 (state shown in FIG. 8). The concave portion 50 is for molding the web Ya of the antenna body shown in FIG. 9 (a portion corresponding to the web E in FIG. 10) at the time of resin molding.

In the movable mold 2, the air suction passages 51 and 52, which open to the cavity forming surface 45 through the sliding contact portion between the cavity plate 43 and the ring block 46, and open in the film suction portion 49, are provided at regular intervals in the circumferential direction. It is provided. The air suction passages 51 and 52 are guided to the back of the cavity plate 43 and communicated with an air suction means (not shown) via an annular air passage 53 provided in the portion.

Next, a molding operation in the mold device having the above structure will be described.

As shown in FIG. 1, the stationary die 1 and the movable die 2 are separated from each other with a constant space, and the suction head 3 is in the raised position. In this standby state, the support frame 24 is engaged with the engaging groove 30 of the suction head 3 as shown in FIG. 3, and the suction head 3 is positioned with respect to the film preforming die 4.

From this state, on the front surface of the suction head 3 and the preforming die 4
And the thermoplastic resin film X is supplied by an appropriate means. With the supply, the three-way switching valve 14 connects the vacuum pump 15 to the suction head 3 to apply an air suction force to the head, thereby causing the suction head 3 to move. Suction air through the ventilation holes 11 ... 11,
The resin film X is adsorbed to the film adsorption surface 3a by the adsorption force. In addition, this adsorption is the base sheet of the resin film X.
It is performed so that X ₁ is brought into close contact with the adsorption surface 3a.

After the suction, the film preforming die 4 is advanced with respect to the suction head 3 by the operation of the fluid pressure cylinder 25A, the positioning pin 26 is inserted into the pin hole 31, and the preforming die 4 and the suction head 3 are aligned. In the state, both 3 and 4 are joined.

In this joining, first, the peripheral portion of the resin film X is sandwiched between the clamp plate 20 on the suction head 3 side and the holder 22, and the holder 22 further advances to retract the clamp plate 20 against the spring member 21. As a result, the flat portion 18 and the respective edge portions 19 and 29 of the holder 22 are engaged with each other, and the resin film X is cut around the film suction surface 3a. And
After that, the fluid pressure cylinder 25B is operated, the die main body 23 is moved forward, and the film forming portions 27 and 28 are fitted to the convex base portion 17 and the flat portion 18, as shown in FIG. Molding for X is done.

With this molding, as shown in FIG. 6, a resin film X having a circular shape slightly larger than the radio wave reflection surface of the antenna body is formed.
Is cut out, and the peripheral portion of the cut out resin film is imprinted with the curved portion Xa and the flat portion Xb.

Next, as the film preforming die 4 is moved backward and separated from the suction head 3, the suction head 3 descends to the position of the chain line in FIG. 1 while adsorbing the preformed resin film X, The resin film X is carried in on the front surface of the movable mold 2.

Then, the solenoids 9, 9 are excited, and the suction head 3 moves forward toward the movable mold 2 and comes into close contact with the movable mold 2. This contact causes the flat portion 18 and the clamp plate 20 to contact the ring block 46 as shown in FIG. 7, but the ring block 46 is kept in the protruding state by the force of the spring members 47a, 47a and does not retract. Also, the resin film X is a preformed curved portion.
Xa is fitted into the recessed portion 50 of the movable die 2, and the flat portion Xb is sent to the front surface of the cavity forming surface 45 in a state of being in contact with the film suction portion 49.

From this state, the vacuum pressure molding of the resin film X is performed. That is, in the movable mold 2, the air suction means is operated,
The air between the resin film X and the cavity constituting surface 45 is discharged to the outside from the air passage 53 through the air suction passages 51 and 52. Then, after the space between the resin film X and the cavity forming surface 45 is evacuated, the compressed air is sent from the compressor 16 to the suction head 3 through the air hose 13 by switching the three-way switching valve 14 in the suction head 3. Compressed air is ejected from the ventilation holes 11 ... Therefore, the suction action due to the vacuum being drawn between the resin film X and the cavity constituting surface 45 and the air pressure blown from the suction head 3 separates the resin film X from the film sucking surface 3a and presses it against the cavity constituting surface 45. Depending on the action,
The resin film X is adsorbed so as to substantially follow the cavity forming surface 45. The resin film X is the base sheet X ₁
Since the side was adsorbed by the adsorption head 3, the weather resistant layer X ₃ faces the cavity constituting surface 45.

After the vacuum pressure forming, the suction head 3 retracts and rises. However, in the movable mold 2, the air suction force by the air suction means is continuously exerted between the resin film X and the cavity forming surface 45 to maintain the suction state of the film, and the air suction is continued until the injection of the molten resin is completed. Let
Therefore, the flat portion Xb of the preformed peripheral portion of the resin film X is attracted to the film attracting portion 49 of the movable die 2, and the curved portion Xa is continuously attracted to the recessed portion 50.

After the suction head 3 is lifted, the fixed die 1 and the movable die 2 are clamped. By this mold clamping, the ring block 46 is retracted against the spring members 47a, 47a, and the recessed portion 50 is continuously connected to the convex curved surface of the cavity forming surface 45 as shown in FIG. In the mold clamped state, the flat portion Xb of the resin film X is clamped by the film suction portion 49 of the movable die 2. However, the clamping force of this portion does not prevent the flat portion Xb from being dragged into the cavity by the pressure at the time of resin injection described below. Then, the molten resin Y is injected from the gate into the cavity, and the heat and pressure at that time cause the resin film X to appropriately expand and form a cavity surface.
Completely adheres to 45, and the antenna body is resin molded in this state. Then, in this molding, the base material sheet X ₁ of the resin film X is melted and integrated with the injection resin,
The resin film X is attached to the resin molded product (state shown in FIG. 9).

By the way, in the mold clamped state, the resin film X is formed into a curved portion Xa such that the peripheral portion of the film adhered to the web Ya in FIG. 9 of the reflector main body is preliminarily formed substantially along the web Ya. Therefore, before the resin injection, the turn-back is already attached, and the base point of the turn-back is determined. Therefore, unlike the conventional case, the resin is not largely folded back at once, the folding point is constant, the stress acting on the folding portion is small, and the variation of the stress does not occur.
Therefore, the resin film X is uniformly deformed at the time of resin injection, and the resin film X in which the radio wave reflection layer X ₂ is formed of an ammonium sheet having poor stretchability.
Even if is used, the obtained product does not have wrinkles or distortion in the resin film portion adhered to the web Ya.

In the mold clamping state prior to resin molding, the preformed flat portion Xb of the resin film X is clamped between the fixed die 1 and the movable die 2, and the flat portion Xb is injected with resin. It is dragged into the recess 50 by the pressure at the time. Therefore, in the obtained product, the resin film X has a shape in which the film end surface Xc is embedded inside the web Ya as shown in FIG.

In the resin molding in the above embodiment, the antenna body was provided with the web Ya and the flange Yb, but it is also possible to provide only the web Ya, and the shape shown in FIG. 10 is an example in that case. Conceivable.

(Effect of the Invention) As is clear from the above description, according to the present invention,
Before loading the thermoplastic resin film into the mold, cut out a size larger than the shape of the radio wave reflecting surface with the resin film adsorbed by the adsorption head, and press the die body of the preforming die against the adsorption head. Thus, the peripheral portion of the resin film after cutting is curved in the bending direction of the web with respect to the radio wave reflection surface at the portion corresponding to the boundary portion between the radio wave reflection surface of the antenna body and the web in the peripheral portion of the resin film. Shape becomes closer to the final shape. Therefore, at the time of injection molding of the resin, the starting point of folding back is constant, and even for a resin film having poor elasticity, the peripheral edge of the resin film is adhered to the web portion evenly by the injection pressure, and the film folding back is performed. The stress acting on the part is small and uniform, the expansion and contraction of the film is constant in every part, the wrinkles of the film do not occur on the web part in the product, and the antenna reflector with excellent product quality can be obtained.

[Brief description of drawings]

The drawings show an embodiment of a method for manufacturing a reflector for an antenna according to the present invention, FIG. 1 is a schematic configuration diagram of a mold apparatus for embodying the method of the present invention, and FIG. 2 is an example of a resin film used for the method of the present invention. FIG. 3 is an enlarged view of the suction head in FIG. 1, FIG. 4 is an enlarged view of the die in FIG. 1, and FIGS. 5 to 9 are explanatory views of the molding operation. FIG. 5 is an explanatory view of the film preforming operation, FIG. 6 is a sectional view of the preformed resin film, FIG. 7 is an explanatory view of the film suction operation to the movable mold, FIG. FIG. 10 is a diagram for explaining the resin molding operation, and FIG. 10 is a sectional view showing a modified example of the antenna reflector. FIG. 11 is a perspective view of a reflector for an antenna obtained by the prior art. X ...... resin film, X ₁ ...... film substrate (substrate sheet), X ₂ ...... radio wave reflecting layer, X ₃ ...... weathering layer, Y ...... molten resin, Ya ...... Webb 1 ...... fixed Type, 2 ... movable type,
3 …… Suction head, 4 …… Film preforming mold, 45 ……
Cavity configuration surface.

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-64-89603 (JP, A) JP-A-1-151306 (JP, A) JP-A 61-63425 (JP, A) JP-A 62- 196113 (JP, A)

Claims (1)

[Claims] 1. A thermoplastic resin film having a radio wave reflection layer and a weather resistant layer laminated on one surface of a film substrate between a fixed die and a movable die to convey the fixed die and the movable die. After tightening, a molten resin is injected from the fixed mold into the cavity formed between the two molds to form an antenna main body having a web portion around the radio wave reflection surface, and at the same time around the antenna main body. A method of manufacturing a reflector for an antenna, comprising depositing a resin film, comprising: adhering a film preforming die to the adsorption head in a state where the film substrate side of the resin film is adsorbed to the adsorption head. A film cutting step of cutting out a circular shape slightly larger than the shape of the radio wave reflection surface, and pressing the die main body of the preforming die against the suction head, thereby cutting the periphery of the resin film. In the preforming step of bending a portion of the antenna body corresponding to the boundary between the radio wave reflection surface and the web in the bending direction of the web with respect to the radio wave reflection surface, the preformed resin film is still adsorbed by the adsorption head. A film transporting step of carrying in the front surface of the cavity forming surface of the movable mold, and a suction head is pressed against the movable mold to sandwich the peripheral edge portion of the resin film between the two, and between the cavity forming surface and the resin film. Film setting step of adsorbing the resin film to the movable mold by sucking air, and withdrawing the adsorption head from the front position of the movable mold, and then clamping the movable mold and the fixed mold, and between the two molds. Of a reflector for an antenna, which comprises a resin molding step of injecting molten resin from a fixed mold into a cavity formed in Law.