JP2002200625A - Apparatus for molding molded article and molding method using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for molding a molded article capable of shortening the production cycle of the molded article and stabilizing quality, and its molding method. SOLUTION: The molding apparatus for molding a steering wheel is equipped with a mold, a urethane injection device, a film forming material injection device 30 and a vacuum mechanism. In the film forming material device 30, a predetermined amount of a film forming material to be injected in a cavity is weighed by a weighing cylinder 40 to be injected in the cavity by an injection cylinder 50. Thereafter, the cavity is evacuated by the vacuum mechanism and, then, a urethane resin is injected in the cavity by the urethane injection device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding apparatus and a molding method for molded articles.

[0002]

2. Description of the Related Art One of conventionally known molded products is, for example, a steering wheel for a vehicle. This steering wheel is formed by disposing a core material at a predetermined position in a cavity of a molding die, injecting a resin as a molding material into the cavity, cooling the resin in the molding die, and curing the resin. I have. Polyurethane (PUR) is generally used as a molding material for the steering wheel. However, since polyurethane is inferior in light resistance and may turn yellow, the surface of the polyurethane part is covered with a light-resistant surface protective material, a so-called mold coat material.

In forming such a mold coat material layer, the following method is used. First, as a pre-process for performing the molding, a material for a mold coat is applied to the cavity in a state where the mold is opened, for example, by a spray gun or the like. Thereafter, the core metal is placed in a cavity, the mold is closed, and normal molding is performed (first conventional method).

On the other hand, as a pre-process for performing the molding, a solution containing a mold coating material is poured into a cavity in a state where the mold is opened, and the core is placed in the cavity and the mold is closed. Then, there is a method in which the mold coating material poured into the cavity is vaporized by reducing the pressure in the cavity, adheres to the inner wall surface of the cavity, and then the normal molding is performed (second conventional method). .

[0005]

However, when each of these methods is used, the following problems have occurred.
That is, in the first conventional method, the mold coating material applied by the spray gun easily adheres to a portion other than the inner wall surface of the cavity of the molding die, for example, a parting surface between the fixed die and the movable die. The mold coat material adhered to portions other than the cavity remains as burrs in the formed steering wheel. When such burrs are generated, there is a problem that a step of removing them is required. In addition, for example, there is a possibility that the mold coating material is not sufficiently applied to the inner wall surface of the cavity or the like that is substantially orthogonal to the mold parting surface of the molding die, causing uneven coating. When such uneven coating occurs, the quality of the steering wheel as a product is reduced.

In the second conventional method, the operation of pouring the mold coat material into the cavity is performed by an operator of the molding apparatus using a container such as a polycup. For this reason, for example, the amount of the material to be put into the same container differs for each product, and the amount of the material to be poured into the cavity becomes unstable. As a result, there is a problem that the thickness of the mold coat material layer in the molded product varies from one molded product to another, and the quality of the product becomes unstable. In addition, there is a problem in that the number of operations for measuring and pouring a predetermined amount of the mold coat material into the container increases, so that the manufacturing cycle becomes longer.

In the case of a molded product other than a steering wheel, a predetermined amount of a film-forming material for forming a predetermined film is injected into the cavity inner wall surface of the molding die during molding. However, these facts are generally common.

The present invention has been made by paying attention to such problems existing in the prior art. An object of the present invention is to provide a molding apparatus and a molding method for a molded article that can shorten the production cycle and stabilize the quality of the molded article.

[0009]

In order to achieve the above-mentioned object, the invention according to claim 1 of the present application, which relates to an apparatus and a method for molding a molded article, is directed to injection of molding material into a cavity of a molding die. Prior to the above, in a molding device of a molded product that is to form a predetermined coating on the inner wall surface of the cavity,
A measuring mechanism for measuring a film forming material for forming the film to a predetermined amount, an injection mechanism for injecting the measured film forming material into the cavity, and an inside of the cavity with the mold closed. The gist of the present invention is to provide a pressure reducing mechanism for reducing the pressure.

According to the first aspect of the present invention, since the film-forming material injected into the cavity of the mold is measured to a predetermined amount by the measuring mechanism, the injection amount is increased every time the film-forming material is injected. The change is suppressed. Thus, for example, when the film is transferred to the surface of a molded product, it is possible to suppress the thickness and the like of the film forming material portion from being varied for each molded product. As a result, it is possible to suppress the occurrence of variation in the quality of the molded product and to stabilize the quality. In addition, since the work of measuring the material can be performed efficiently, the manufacturing cycle of the molded product can be shortened.

When the pressure in the cavity is reduced to a predetermined value by the pressure reducing mechanism, the film-forming material injected into the cavity starts to boil due to the boiling point lowering action. The boiling causes the material to fill the cavity due to volume expansion and scattering, and a part of the material adheres to the wall surface. At this time, the film-forming material adheres substantially uniformly to the entire wall surface of the cavity, so that there is no unevenness in coating, as in the case of application using a spray gun or the like. Also in this respect, it is possible to suppress the occurrence of variation in the quality of the molded product,
Quality can be stabilized.

Further, since the decompression by the decompression mechanism is performed in a state where the mold is closed, the film-forming material does not adhere to portions other than the cavity, such as the mold parting surface of the mold. As a result, the formation of burrs on the molded product is suppressed, and a burr treatment step or the like after molding is not required, so that the production cycle can be prevented from being lengthened.

According to a second aspect of the present invention, in the first aspect of the present invention, the injection mechanism prevents the material injected into the mold from flowing into the injection mechanism again. The gist of the present invention is to further include a backflow prevention unit.

According to the second aspect of the present invention, in addition to the effect of the first aspect, the film forming material once injected into the mold is again injected into the injection mechanism by the inflow prevention means. Inflow can be prevented. Also,
It is also possible to prevent the molding material from flowing into the injection mechanism. As a result, the measured film forming material can be more accurately injected into the cavity.

According to a third aspect of the present invention, in the first or the second aspect of the invention, the molding apparatus is configured such that the film forming material is held in a holding state other than at the time of measuring and pouring. The gist of the present invention is to further include a circulation mechanism that circulates the film-forming material between the tank that stores the film-forming material, the metering mechanism, and the injection mechanism.

According to the third aspect of the present invention, in addition to the effects of the first or second aspect,
Even if, for example, a film-forming material that makes the contained components non-uniform in the stationary state is used for molding the molded product, the non-uniform components can be suppressed by the circulation mechanism.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the film-forming material comprises at least a part of a surface of the molded article. And a component that vaporizes under reduced pressure in the cavity by the pressure reducing mechanism.

According to the invention described in claim 4 of the present application, in addition to the function of the invention described in any one of claims 1 to 3, at least a part of the surface of the molded product is provided with a mold coat. The thickness of the material can be formed substantially uniformly and efficiently.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the film-forming material contains a pigment as one of its components. The gist is to do.

According to the fifth aspect of the present invention, in addition to the effect of the first aspect of the present invention, a molded product can be colored to a desired color. Thus, the design can be improved. In this case, in order to suppress the precipitation of the pigment component, it is preferable to use a molding device having a circulation device.

According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, the measuring mechanism also functions as the injection mechanism. Things.

According to the sixth aspect of the present invention, in addition to the function of the first aspect of the present invention, the structure of the entire molding apparatus is simplified. be able to.

Further, the invention according to claim 7 of the present invention is directed to a method of molding a molded product, wherein a predetermined coating is formed on an inner wall surface of the cavity before the molding material is injected into the cavity of the molding die. A measuring step of measuring the film forming material to a predetermined amount, an injecting step of injecting the measured film forming material into the cavity, and a depressurizing step of depressurizing the inside of the cavity with the mold closed. The gist is that.

According to the seventh aspect of the present invention, substantially the same operation as that of the first aspect can be realized.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a molding apparatus for molding a steering wheel for a vehicle and a molding method thereof will be described below with reference to FIGS.

First, a steering wheel forming apparatus will be described with reference to FIGS. As shown in FIG. 1, the molding apparatus includes a mold 10 as a molding die, a film forming material injection device 30, a urethane injection device 25, and a pressure reducing mechanism 70. The urethane injection device 25 includes:
This is a device for injecting a urethane resin as a molding material into the mold 10 when molding the steering wheel. The film forming material injection device 30 is a device for injecting a film forming material for coating the surface of the urethane resin layer of the steering wheel into the mold 10. Here, the film forming material contains a solvent such as methyl ethyl ketone (MEK) and isopropyl alcohol (IPA), a solid content of a mold coat material and a pigment. The pressure reducing mechanism 70 is a device that reduces the pressure inside the mold 10 when forming the steering wheel.

Hereinafter, the mold 10, the film forming material injection device 30 and the pressure reducing mechanism 70 will be described. In addition, as for the urethane injection device 25, an injection molding device that is usually used when molding a steering wheel is used, and the description thereof is omitted.

First, the configuration of the mold 10 will be described.
As shown in FIG. 2, the mold 10 is provided in a box 13 including a frame 11 and a lid 12. The lower mold 14 of the mold 10 is fixed to the frame 11, and the mold 1 is attached to the lid 12.
The upper mold 15 is fixed. On the other hand, a seal member 16 is provided at a joint of the lid 12 and the frame 11.

When the upper end surface of the frame 11 and the lower end surface of the lid 12 in the box 13 are separated from each other, the mold surfaces of the lower mold 14 and the upper mold 15 of the mold 10 are separated from each other and the mold is opened. State. Conversely, frame 1 in box 13
When the upper end surface of the mold 1 contacts the lower end surface of the lid 12, the mold 1
The mold surfaces of the lower mold 14 and the upper mold 15 are brought into contact with each other, so that the mold is clamped. When the mold 10 is in the closed state,
The inside of the box 13 is sealed by the frame 11 and the lid 12.

An annular concave groove 17 is formed in the lower mold 14 at substantially the center of the mold surface. On the other hand, the upper die 15 is also provided with an annular concave groove 18 at a position corresponding to the concave groove 17 on the mold surface. These grooves 17, 18
Forms a cavity 19 when the steering wheel is formed by clamping the mold 10.

The lower mold 14 has an injection groove 20 formed on a parting surface thereof. The injection groove 20 is formed outward from the concave groove 17 and bifurcates in the middle thereof (see FIG. 1). On the other hand, the upper die 15 is also provided with a bifurcated injection groove 21 at a position corresponding to the injection groove 20 on the parting surface thereof. These injection grooves 20 and 21 form a gate 22 by clamping the mold 10. The cavity 19 and the outside of the box 13 communicate with each other via two openings 11 a formed in the gate 22 and the frame 11.

The upper die 15 has an outer surface and a concave groove 18.
Is formed with the inner bottom surface of the through hole 23. When the mold 10 is in the mold clamped state, the cavity 19 and the space 13 a in the box 13 communicate with each other through the through hole 23.

The frame 11 has a concave groove 17 of the lower mold 14.
A fixing member 24a projecting upward through the center of the cover member 12 is provided, and a fixing member 24b is also provided on the lid 12 at a position corresponding to the fixing member 24a. When the mold 10 is clamped during molding of the steering wheel, the core metal is fixed at a predetermined position by the fixing members 24a and 24b.

Next, the structure of the pressure reducing mechanism 70 will be described. As shown in FIGS. 1 and 2, the pressure reducing mechanism 70 includes a vacuum pump 71. The vacuum pump 71 is connected to the pipe 7
2. It is connected to the frame 11 via a valve 73 and a discharge pipe 74. When the vacuum pump 71 is operated in a state where the inside of the box 13 is sealed, the space 1
The air in 3a is discharged to the outside via the decompression mechanism 70,
The pressure in the box 13 is reduced. At this time, the air in the cavity 19 is also discharged to the outside through the through hole 23, the space 13a and the pressure reducing mechanism 70, and the pressure in the cavity 19 is reduced.

Next, the structure of the film forming material injection device 30 will be described with reference to FIG. FIG. 3 is a schematic configuration diagram schematically showing the overall configuration of the film forming material injection device 30.

As shown in FIG. 3, the film forming material injection device 30 includes a tank 31, a measuring cylinder 40 as a measuring mechanism, and an injection cylinder 50 as an injection mechanism. The tank 31 stores a film forming material. The metering cylinder 40 is used to store the film forming material in the cavity 19.
Weigh to a predetermined volume just to be poured into. The injection cylinder 50 injects the same material measured by the measuring cylinder 40 into the cavity 19. The tank 31, the measuring cylinder 40, and the injection cylinder 50 are connected to each other so that the film forming material can circulate. Here, the measuring cylinder 40 and the injection cylinder 50 are air cylinders that operate based on the supply and discharge of air to and from these cylinders.

More specifically, the tank 31 is connected to the measuring cylinder 40 via a passage 32a, a pump 33 (a diaphragm pump in this example), a regulator 34, a throttle valve 35a and a control valve 36. Here, the pump 33
This is for pumping the film forming material from the tank 31 and sending it to the measuring cylinder 40. The regulator 34 is provided by the diaphragm pump 33 and the measuring cylinder 40.
In the passage 32a, the pressure acting on the inner wall surface of the passage 32a is adjusted to be substantially constant by the film forming material flowing therethrough. Also, the throttle valve 35a
Is for adjusting the flow rate of the film forming material from the tank 31 to the measuring cylinder 40.

The control valve 36 is for switching the connection state between the tank 31 and the measuring cylinder 40 depending on the position of the valve body, and is set as a normally open valve in the present embodiment. By the way, the position of the valve body of the valve 36 is
It is determined by the presence or absence of the urging force (electromagnetic force) generated by the solenoid 36a. That is, when an urging force is generated by the solenoid 36a, the urging force is applied to the spring 36a.
Since the valve body is moved against the urging force of b, the communication between the tank 31 and the measuring cylinder 40 is cut off. On the other hand, when the urging force of the solenoid 36a is not generated, the urging force of the spring 36b moves the valve body, so that the tank 31 and the measuring cylinder 40 are communicated. In this state, the film forming material is supplied from the tank 31 to the measuring cylinder 40.

The measuring cylinder 40 is connected to the injection cylinder 50 via a passage 32a. The injection cylinder 50 is connected to the tank 31 via the passage 32a and the control valve 37. Here, the control valve 37
Is for switching the connection state between the injection cylinder 50 and the tank 31 similarly to the control valve 36, and is set as a normally open valve. When no urging force is generated by the solenoid 37a, the injection cylinder 50
And the tank 31 are communicated. Also, the solenoid 37a
When the urging force is generated by the
And the tank 31 is disconnected.

The tank 31 is connected to a charging passage 32b for charging the film forming material into the tank 31. In the middle of the charging passage 32b, the charging port and the tank 31 are communicated and blocked. And a throttle valve 35b for adjusting the pressure. Further, the tank 31 is provided with a stirrer 38 for stirring the film forming material inside the tank 31.

The film forming material injection device 30 includes a pump 80 for supplying air to the diaphragm pump 33, the measuring cylinder 40, the injection cylinder 50, and the stirrer 38 to operate them.

The pump 80 is connected to direction switching valves 83, 85, 88, a throttle valve 35c, and a stirrer 38 via an air passage 81 and a regulator 82. The regulator 82 regulates the pressure of the air acting on the inner wall surface of the air passage 81 at a substantially constant pressure.

The direction switching valve 83 is connected to the diaphragm pump 33 via an air passage 84. Also,
The direction switching valve 83 switches the connection state between the air passage 81 and the air passage 84 depending on the presence or absence of the urging force of the solenoid 83a. That is, when the urging force is generated by the solenoid 83a, the air passage 81 and the air passage 84 communicate with each other, and the air is supplied to the diaphragm pump 33. On the other hand, when the urging force is not generated, the communication between the air passage 81 and the air passage 84 is cut off, and the air passage 84 is opened to the atmosphere, so that the air is discharged from the diaphragm pump 33 to the atmosphere.

The direction switching valve 85 is provided in the air passage 8.
It is connected to the measuring cylinder 40 via 6a and 86b. The direction switching valve 85 has its solenoids 85a, 85b
Air passage 81 and air passage 8 depending on the presence or absence of the urging force
6a and 86b are switched. That is, when only the urging force by the solenoid 85a is generated, the valve moves to the left in FIG.
1 is communicated with the air passage 86b, and the air passage 86a is open to the atmosphere. On the other hand, when only the urging force by the solenoid 85b is generated, the valve body moves to the right in the figure to connect the air passage 81 and the air passage 86a, and the air passage 86b is opened to the atmosphere. .

On the other hand, when no urging force is generated by the solenoids 85a and 85b (the state shown in FIG. 3), none of the air passages 81, 86a and 86b is communicated, and the internal pressure of the air passages 86a and 86b is maintained. Is done. In the middle of the air passages 86a, 86b, the respective passages 86a, 86a
Flow control valve 87a for adjusting the flow rate of air at 86b
And a check valve 87b for preventing backflow of air are provided.

The directional control valve 88 is connected to the air passage 8.
It is connected to the injection cylinder 50 via 9a and 89b. The direction switching valve 88 has an air passage 81 and air passages 89a, 89a, 8b depending on the presence or absence of the urging force of the solenoid 88a.
9b is switched. That is, when the urging force is generated by the solenoid 88a, the air passage 81 and the air passage 89a are communicated, and the air passage 89b is opened to the atmosphere. On the other hand, the solenoid 88
When no urging force is generated by the air passage 81 a
And the air passage 89b are communicated with each other.
9a is open to the atmosphere.

In FIG. 3, the throttle valve 35c connected to the air passage 81 is branched and connected in the middle of the passage 32a between the tank 31 and the diaphragm pump 33. Thereby, the pump 80 is controlled via the throttle valve 35c.
, Air can be injected into the passage 32a. This is for efficiently collecting the film forming material in the tank 31 when the film forming material in the film forming material injection device 30 is switched to another material or the like.

Next, the structures of the measuring cylinder 40 and the injection cylinder 50 will be described in detail with reference to FIGS. As shown in FIG. 4, the measuring cylinder 40 includes a cylinder main body 41, a piston 42 accommodated in the cylinder main body 41 so as to be able to reciprocate, and an adjusting screw 43 for adjusting a moving amount of the piston 42. I have.

The interior of the cylinder body 41 is divided into three spaces 44 to 46 by two partition walls 41a and 41b. The cylinder body 41 has two through-holes 47 at its ends where the space 44 communicates with the outside.
a, 47b are formed. Also, the cylinder body 41
In the vicinity of the partition walls 41a and 41b, through holes 48a and 48b for communicating the space 45 with the outside are formed.

The piston 42 has an extruded portion 42a provided at the front end thereof and sliding in the space 44, and a substantially central portion in the longitudinal direction of the piston 42 and slid in the space 45. A pressure receiving portion 42b is formed. For this reason, the space 44 is divided into two spaces 44 by the pushing portion 42a.
a, 44b, and the space 45 is also partitioned into two spaces 45a, 45b by the pressure receiving portion 42b.

The space 44a communicates with the tank 31 through a through hole 47a and a passage 32a, and communicates with the injection cylinder 50 through a through hole 47b and a passage 32a. On the other hand, the space 45a communicates with the air passage 86a through the through hole 48a, and the space 45b communicates with the air passage 86b through the through hole 48b.

The metering cylinder 40 having such a structure is provided with the pump 80 and the space 45 by switching the direction switching valve 85.
a and the space 45b is opened to the atmosphere, air is supplied to the space 45a and the air in the space 45b is discharged to the atmosphere. Then, the pressure receiving portion 42b of the piston 42 moves rightward in the drawing, and along with this movement, the pushing portion 42a of the piston 42 also moves in the same direction. Then, the movement of the piston 42 in the same direction is stopped when the end 42c of the piston 42 comes into contact with the tip 43a of the adjusting screw 43 (FIG. 4B). On this occasion,
When the tank 31 and the measuring cylinder 40 are in communication with each other, the film forming material is fed into the space 44a by an amount corresponding to the increase in the volume of the space 44a due to the movement of the piston 42. In this way, the film forming material is weighed to a predetermined amount.

On the other hand, by switching the direction switching valve 85,
When the pump 80 is communicated with the space 45b and the space 45a is opened to the atmosphere, air is supplied to the space 45b and the air in the space 45a is discharged to the atmosphere. Then, the pressure receiving portion 42b of the piston 42 moves leftward in the figure, and the pushing portion 4b of the piston 42 moves with this movement.
2a also moves in the same direction. When the piston 42 moves in the same direction, the end 42c of the piston 42 is
1b, and is stopped by contact (FIG. 4 (a)).
At this time, the tank 31 and the measuring cylinder 40 are shut off,
When the injection cylinder 50 and the tank 31 are shut off, the film forming material is fed into the injection cylinder 50 by an amount corresponding to the reduction in the volume of the space 44a due to the movement of the piston 42. In this way, a predetermined amount of the film forming material is fed into the injection cylinder 50.

Here, the amount at which the film forming material is measured is adjusted by the adjusting screw 43. That is, the more the adjustment screw 43 is screwed into the cylinder main body 41, the smaller the amount of movement of the piston 42 becomes.
The amount of the film forming material fed into the space 44a from the space is also reduced.

On the other hand, as shown in FIG.
Reference numeral 0 includes a cylinder body 51 and a piston 52 housed in the cylinder body 51 so as to be able to reciprocate. The cylinder body 51 has a housing 51 having a substantially U-shaped cross section at one end thereof.
a, and two spaces 53 a, 53 are formed by the housing 51 a and a pressure receiving portion 52 a provided at an end of the piston 52.
b is formed. In the vicinity of the opening of the housing 51a, a through-hole 55a for communicating the space 53a with the outside is formed.
A through hole 55b is formed in the bottom of the cylinder body 51 to allow the space 53b to communicate with the outside. Space 53a
Is communicated with the air passage 89a through the through hole 55a, and the space 53b is communicated with the air passage 89b through the through hole 55b.

The cylinder body 51 has an injection port 54 formed at the other end thereof, which is opened and closed by the reciprocating motion of the piston 52. The injection port 54 is connected to the opening 11a of the box 13. The inner side of the injection port 54 is formed in a tapered shape. The tip of the piston 52 is also formed in a tapered shape.
4 is closed by the piston 52 without any gap. Accordingly, when the urethane resin is injected into the mold 10 by the urethane injection device 25, the mold 10
The urethane resin injected into the injection cylinder 50 does not flow back into the injection cylinder 50.

The cylinder body 51 includes a piston 5
Two through-holes 56a and 56b are formed to communicate the accommodation hole 51b accommodating 2 with the outside. Through hole 56a
Is connected to the measuring cylinder 40 via the passage 32a, and the through hole 56b is connected to the tank 31 via the passage 32a and the like.

The piston 52 has two through holes 5.
A recess 52b is formed over the entire circumference to enable communication between 6a and 56b. In addition, the same piston 52
A step 52c is formed between the tapered tip portion and the concave portion 52b so as to contact the inner surface of the housing hole 51b.

In the injection cylinder 50, the direction switching valve 8
When the pump 80 and the space 53a are communicated by the switching of 8, the space 53b is opened to the atmosphere, air is supplied into the space 53a, and the air in the space 53b is discharged to the atmosphere. Then, the pressure receiving portion 52 of the piston 52
a moves rightward in the figure, and the injection port 54
Is opened, and the step 52c of the piston 52 moves in the same direction. And the piston 52 is
Is moved in the same direction until the pressure receiving portion 52a contacts the inner bottom surface of the housing 51a (FIG. 5B).

At this time, the through hole 56a and the through hole 56b are shut off by the step 52c, and the mold 10 and the measuring cylinder 40 are communicated through the inlet 54 and the through hole 56a. Therefore, the film forming material sent from the measuring cylinder 40 to the injection cylinder 50 is injected into the cavity 19 of the mold 10.

On the other hand, by switching the direction switching valve 88,
When the pump 80 communicates with the space 53b and the space 53a is opened to the atmosphere, air is supplied into the space 53b, and the air in the space 53a is discharged to the atmosphere. Then, the pressure receiving portion 52a of the piston 52 moves leftward in the drawing, and the step 52c of the piston 52 also moves in the same direction along with this movement. And the piston 52 is the piston 5
2 is moved in the same direction until the tip end closes the injection port 54 of the cylinder body 51 (FIG. 5A).

At this time, the through-hole 56a and the through-hole 56b communicate with each other, and the measuring cylinder 40 and the tank 31 communicate with each other via the injection cylinder 50. Accordingly, the film forming material sent from the measuring cylinder 40 to the injection cylinder 50 is sent from the injection cylinder 50 to the tank 31 via the passage 32a as it is. Thus, the passage 32a forms a circulation mechanism. Then, while maintaining the communication state of the through holes 56a and 56b of the injection cylinder 50, the film forming material is fed from the tank 31 to the measuring cylinder 40 and further to the tank 31 via the injection cylinder 50. Material circulation will take place. In this embodiment, the film-forming material is circulated when the film-forming material is measured by the measuring cylinder 40 and in a holding state other than when the injection cylinder 50 injects the film-forming material into the cavity 19.

Next, a method of forming a steering wheel using the above-described forming apparatus will be described with reference to FIGS. First, with the mold 10 opened, a mold release agent is applied to the inner wall surfaces of the concave groove 17 of the lower mold 14 and the concave groove 18 of the upper mold 15 which form the cavity 19. This release agent is made of wax, silicone oil, or the like, and serves to suppress the adhesion of the formed steering wheel to the mold 10 and facilitate the removal of the formed steering wheel. Then, as shown in FIG. 6, a core is set in the mold 10, and the mold 10 is closed and clamped.

In the present embodiment, after this mold clamping step,
Urethane injection device 25 into cavity 19 of mold 10
Prior to the injection of the urethane resin by the
The step of forming a coating on the inner wall surface is performed.

The step of forming this coating is as follows:
It is performed in the procedure of (g). (A) When the mold 10 is completely clamped in the previous step, the control valve 37 is switched to be closed to shut off the communication between the injection cylinder 50 and the tank 31.

(B) With the control valve 37 closed, the piston 42 is moved in a direction in which the volume of the space 44a of the measuring cylinder 40 increases (a measuring step). Here, since the control valve 36 is a normally open valve, the film forming material in the tank 31 is fed into the space 44 a of the measuring cylinder 40 and is metered to the amount to be injected into the cavity 19 by this step.

(C) After the movement of the piston 42 of the measuring cylinder 40 is completed, the diaphragm pump 33 is stopped and the control valve 36 is closed. (D) The piston 52 of the injection cylinder 50 is moved to open the injection port 54, and the piston 42 is moved in a direction in which the volume of the space 44a of the measuring cylinder 40 is reduced (injection step).

(E) After the movement of the piston 42 of the measuring cylinder 40 is completed, the piston 52 of the injection cylinder 50 is moved to close the injection port 54. (F) The vacuum pump 71 is operated to put the inside of the cavity 19 of the mold 10 into a reduced pressure state, and a film of the film forming material is formed on the inner wall surface of the cavity 19 (pressure reduction step).

(G) The control valves 36 and 37 are opened, and the diaphragm pump 33 is operated to circulate the film forming material among the tank 31, the measuring cylinder 40 and the injection cylinder 50.

Next, urethane resin is injected into the cavity 19 by the urethane injection device 25 while maintaining a predetermined reduced pressure state. Finally, the mold 10 is opened, and the steering wheel having the mold coat layer made of the film forming material transferred to the surface of the urethane resin portion is taken out, and the molding step is completed.

Therefore, according to the present embodiment, the following effects can be obtained. (1) Since the film forming material injected into the cavity 19 of the mold 10 is measured to a predetermined amount by the measuring cylinder 40, a change in the injected amount every time the film forming material is injected is suppressed. Thus, when the mold coat is transferred to the surface of the steering wheel, it is possible to suppress the thickness of the mold coat from varying for each steering wheel. As a result, it is possible to suppress the occurrence of variation in the quality of the steering wheel and to stabilize the quality.

(2) Since the work of measuring the film forming material can be performed efficiently, the manufacturing cycle of the steering wheel can be shortened. (3) When the pressure inside the cavity 19 is reduced to a predetermined value by the pressure reducing mechanism 70, the solvent contained in the film forming material injected into the cavity 19 starts to boil due to the boiling point lowering action. When the boiling state continues, the film forming material fills the cavity 19 due to volume expansion or scattering, and a part of the material adheres to the wall surface of the cavity 19. At this time, since the mold coating material contained in the film forming material adheres substantially uniformly to the entire wall surface of the cavity 19, uneven coating does not occur as in the case of applying with a spray gun or the like. Also in this regard, it is possible to suppress the occurrence of variation in the quality of the steering wheel and to stabilize the quality.

(4) The decompression by the decompression mechanism 70 is performed by the mold 10
Is performed in a closed state, so that the film forming material does not adhere to portions other than the cavities 19, such as the mold cutting surface of the mold 10. As a result, the formation of burrs on the molded steering wheel is suppressed, and the quality of the steering wheel can be improved. In addition, the processing step of the molded burrs is not required, and the production cycle is prevented from being lengthened. Can be.

(5) The injection port 54 of the injection cylinder 50 is closed by the piston 52 without any gap.
The coating material and the molding material once injected into the mold 10 can be prevented from flowing into the injection cylinder 50. As a result, the measured film forming material can be more accurately injected into the cavity 19.

(6) The film-forming material is circulated when the film-forming material is weighed by the measuring cylinder 40 and in a holding state other than when the injection cylinder 50 is injected into the cavity 19. For this reason, it is possible to suppress the non-uniformity of the mold coat material and the pigment component contained in the film forming material.

(7) Since the pigment is contained in the film-forming material, the steering wheel can be colored in a desired color, and the design can be improved. (Modification) The embodiment of the present invention may be modified as follows.

In the above embodiment, the diaphragm pump 33, the measuring cylinder 40, and the injection cylinder 50 are configured to operate by air pressure. However, they may be configured to operate by hydraulic pressure, for example.

In the above embodiment, the mold 10 is
It was set so that the parting surface was almost horizontal.
However, the mold 10 may be installed so that the mold surface is substantially vertical.

In the above embodiment, the measuring cylinder 40 as the measuring mechanism and the injection cylinder 50 as the injection mechanism are separately provided. On the other hand, for example, the film forming material measured by the measuring cylinder 40 may be directly injected into the cavity 19 of the mold 10 so that the measuring cylinder 40 may also serve as the injection mechanism. In this case, the configuration of the entire molding apparatus can be simplified.

In the above embodiment, the film-forming material contains a mold coat material, a pigment, methyl ethyl ketone and isopropyl alcohol, but the components of the film-forming material are arbitrary. For example, a material containing a release agent may be used.

In the above embodiment, the molding device is
It was configured to have a circulation mechanism. However, when a film-forming material that does not contain a component that precipitates or separates in a standing state is used as a component of the film-forming material, the circulation mechanism may be omitted.

In the above embodiment, the film forming material is injected after the mold 10 is clamped. However, the injection may be started when the mold 10 is open. In this case, it is preferable that the mold 10 is installed so that the mold surface is substantially horizontal so that the film forming material does not flow out of the cavity 19 of the mold 10.

In the above-described embodiment, an example of molding using a urethane resin has been described. However, the present invention is not limited to this urethane resin. For example, another resin material, a rubber material, or the like may be used.

In the above-described embodiment, an example of the molding apparatus for a steering wheel has been described. However, the present invention
In addition to this molding apparatus, for example, the present invention can be similarly applied to a molding apparatus and a molding method for molding other parts such as an instrument panel, a console box, a glow box, a headrest, an armrest, a door cover, an air spoiler, and a bumper. . In addition, the present invention can be applied to a molding apparatus and a molding method for molding a molded article such as a household electric appliance in addition to a vehicle component.

[0085]

As described in detail above, according to the first or seventh aspect of the present invention, it is possible to suppress the occurrence of variation in the quality of a molded product and to stabilize the quality. it can. Further, the manufacturing cycle of the molded product can be shortened.

According to the second aspect of the present invention, in addition to the effects of the first aspect, the film forming material and the molding material once injected into the mold are injected into the injection mechanism. Inflow can be prevented and the metered film forming material can be more accurately injected into the cavity.

According to the invention of claim 3 of the present application, in addition to the effects of the invention of claim 1 or 2, in addition to the effect of forming a film in which the contained components become non-uniform in a standing state. Even if a material is used, it is possible to suppress the contained components from becoming non-uniform.

According to the invention set forth in claim 4 of the present application, in addition to the effects of the invention set forth in any one of claims 1 to 3, at least a part of the surface of the molded product is provided. In addition, the thickness of the mold coat material can be formed substantially uniformly and efficiently.

According to the invention as set forth in claim 5 of the present application, in addition to the effects of the invention as set forth in any one of claims 1 to 4, the molded article is colored to a desired color. Can improve the design.

According to the invention of claim 6 of the present application, in addition to the effects of the invention of any one of claims 1 to 5, the structure of the entire molding apparatus can be simplified. Can be something.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of an embodiment of a molding apparatus of the present invention.

FIG. 2 is a sectional view showing a mold provided in the molding apparatus.

FIG. 3 is a schematic configuration diagram showing a film forming material injection device of the molding device.

FIG. 4 is a sectional view showing a measuring cylinder provided in the injection device.

FIG. 5 is a sectional view showing an injection cylinder provided in the apparatus.

FIG. 6 is an explanatory diagram relating to a method of forming the steering wheel.

FIG. 7 is an explanatory diagram relating to a method of forming the steering wheel.

[Explanation of symbols]

10: mold as a molding die, 19: cavity, 31 ...
Tank, 32a: passage forming a circulation mechanism, 40: measuring cylinder as a measuring mechanism, 50: injection cylinder as an injection mechanism, 52: piston as backflow prevention means, 5
4 ... Injection port as backflow prevention means, 70 ... Decompression mechanism.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29L 31:30 B29L 31:30 (72) Inventor Kagami Oya Nagahata 1 Address Toyoda Gosei Co., Ltd. F-term (reference) 3D030 DA34 DA54 DA67 DA76 4F204 AA42 AD03 AD11 AD18 AH19 EA03 EB01 EB12 EB22 EF05 EF23 EK09 EK24

Claims (7)

[Claims] 1. A molding apparatus for molding a molded article, wherein a predetermined coating is formed on an inner wall surface of the cavity prior to injecting a molding material into a cavity of a molding die. A measuring mechanism for measuring a forming material to a predetermined amount, an injection mechanism for injecting the measured film forming material into the cavity, and a depressurizing mechanism for depressurizing the inside of the cavity with the mold closed. A molding device for a molded article characterized by the following. 2. The molded product according to claim 1, wherein said injection mechanism further comprises backflow prevention means for preventing the material injected into said mold from flowing into said injection mechanism again. Molding equipment. 3. The molding apparatus circulates the film-forming material between a tank for storing the film-forming material, a metering mechanism, and a pouring mechanism when the film-forming material is held other than at the time of measuring and pouring. The molding device according to claim 1 or 2, further comprising a circulation mechanism. 4. The film-forming material contains a mold coating material covering at least a part of the surface of the molded article and a component which is vaporized under reduced pressure in the cavity by the pressure reducing mechanism. An apparatus for molding a molded article according to any one of claims 1 to 3. 5. The film-forming material according to claim 1, wherein said film-forming material contains a pigment as one of its components.
The molding device for a molded product according to any one of the above. 6. The apparatus according to claim 1, wherein the measuring mechanism also functions as the injection mechanism. 7. A method for molding a molded product, wherein a predetermined coating is formed on an inner wall surface of the cavity prior to injecting the molding material into the cavity of the molding die, wherein the film forming material is measured to a predetermined amount. A molding method, comprising: a step, an injection step of injecting the measured film forming material into the cavity, and a decompression step of depressurizing the inside of the cavity with the molding die closed. .