JP3748481B2 - Injection mold - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plastic injection mold, and more specifically, a so-called side punching (undercut) in which a part of a molding surface needs to be moved back and forth in a direction not parallel to the mold opening direction due to the shape of the molded product. The present invention relates to the structure of an injection mold having a (cut) mechanism.
[0002]
[Prior art]
As is well known, an undercut mechanism that has been conventionally employed in injection molds for molding, for example, a horizontal hole or a horizontally inclined mounting pin, etc., into a plastic molded product is a part of the molding surface. A fluid pressure cylinder was provided for advancing and retreating the transverse block formed in a direction non-parallel to the mold opening direction.
[0003]
By the way, in recent plastic front panels for automobile interiors (referred to as instrument panels, clusters, etc.), a complicated curved surface shape in which the operation portion is inclined toward the driver is required. Therefore, there is a need for an injection mold that can integrally form an inclined molding surface having a relatively large area, or a large number of inclined mounting pins, etc., in an inclined shape that is not parallel to the mold opening direction.
[0004]
However, such a large area molding surface is loaded with several tons to hundreds of tons depending on the injection pressure of the resin during molding. Conventionally, a large-diameter hydraulic cylinder that can withstand the load on the horizontal block It was necessary to support by.
[0005]
[Problems to be solved by the invention]
However, if a large-diameter hydraulic cylinder has to be provided, there is a problem that the manufacturing cost of the mold is greatly increased and the operation time is increased.
[0006]
[Means for Solving the Problems]
Therefore, the injection molding die of the present invention is intended to solve the above-mentioned problem, and is provided with a first cylinder for moving the horizontal block, which forms a part of the molding surface, forward and backward in a direction not parallel to the mold opening direction. In addition, a lock block that intervenes in the orthogonal direction on the back surface of the horizontal block at the time of molding and prevents the horizontal block from retreating is provided by a second cylinder so as to be movable back and forth.
Further, in the injection molding die according to the present invention, the back surface of the horizontal block is formed in a step shape, and the side surface of the lock block is formed in a step shape that can be attached to the back surface of the horizontal block. It is characterized by.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. The injection mold shown in this embodiment is for molding a plastic molded product as shown in FIG. 1 mounted on the front of a driver's seat of an automobile, and its meter mounting surface a is an air conditioner or a car stereo. The fixture mounting surface b is non-parallel, and a large number of mounting pins c and d are integrally projected on the back side of the meter mounting surface a and the fixture mounting surface b.
[0008]
FIG. 2 is a longitudinal sectional view of this injection mold. 1 is a fixed mold, 2 is a movable mold that moves forward and backward in the mold opening direction f indicated by an arrow with respect to the fixed mold 1, and 3 is the fixed mold. In the cavity formed by the mold 1 and the movable mold 2, the plastic molded product is molded by injecting resin into the cavity 3. Reference numeral 4 denotes a horizontal block that forms a part of the molding surface, and a vertical hole 5 is formed in the horizontal block 4 so that the mounting pin d is molded.
[0009]
Reference numeral 6 denotes a first cylinder fixed to the fixed mold 1 by a frame 7 so as to move the horizontal block 4 forward and backward in a direction g which is not parallel to the mold opening direction f. As shown in FIG. Two connecting rods 9, 9 extend in a bifurcated manner on the piston rod of the cylinder 6 via a connecting fitting 8, and the tips of the connecting rods 9, 9 are fixed to the horizontal block 4. The horizontal block 4 has a back surface 10 formed in a stepped shape having several steps. Reference numeral 11 denotes a second cylinder fixed to the fixed mold 1 by a frame 14 so as to be orthogonal to the first cylinder 6. The lock block 12 is connected to the piston rod of the second cylinder 11 via a connecting rod 16. The lock block 12 can be inserted into the rear surface of the horizontal block 4 from the orthogonal direction by the operation of the second cylinder 11. The side surface 13 of the lock block 12 is formed in a stepped shape with the same pitch so that it can be joined to the back surface 10 of the horizontal block 4. Reference numerals 15 and 15 denote cut holes formed in the lock block 12 to avoid collision with the connecting rods 9 and 9.
[0010]
As shown in FIG. 2, the injection mold having the above-described configuration is formed by inserting a lock block 12 from the orthogonal direction to the back surface of the horizontal block 4 in the advanced state, as shown in FIG. By preventing the block 4 from retreating and injecting the resin into the cavity 3 in this state, the molding pressure applied to the transverse block 4 is applied to the fixed mold 1 via the lock block 12. For this reason, the first cylinder 6 is hardly subjected to a large load applied to the horizontal block 4 and can be sufficiently dealt with even if a small pneumatic cylinder is used.
[0011]
Then, when the resin injected into the cavity 3 is solidified, the second cylinder 11 is operated to move the lock block 12 backward as shown in FIG.
Next, as shown in FIG. 5, the horizontal cylinder block 4 is moved backward by the first cylinder 6 to disengage the mounting pin d from the vertical hole 5, and then the movable mold 2 is opened to take out the molded product from the cavity 3.
[0012]
In this embodiment, the back surface 10 of the horizontal block 4 is formed in a staircase shape, and the side surface of the lock block 12 is also formed in a staircase shape that matches the back surface 10, so that the lock block 12 is only retracted by one step. A gap can be formed on the back surface of the horizontal block 4 so that the horizontal block 4 can be retracted, and a large load received by the horizontal block 4 during molding can be distributed to each step surface to receive and support the load at each step. Therefore, there is an advantage in that the load resistance is large, and a gap that allows the horizontal block 4 to move backward only by moving the lock block 12 forward and backward with a small stroke can be formed on the back side of the horizontal block 4. . In addition, since it has a stepped shape, it does not generate any component force in the orthogonal direction unlike the flat inclined surface, so that there is no possibility that a load is applied to the second cylinder 11. Accordingly, the second cylinder 11 can be dealt with by a small hydraulic cylinder.
[0013]
【The invention's effect】
As described above, according to the present invention, by providing the lock block for preventing the horizontal block from retreating, the cylinder for moving the horizontal block forward and backward can be prevented from being subjected to a large load due to molding pressure. Thus, there is no need to provide a large-diameter cylinder as described above, and there are beneficial effects such as greatly reducing the manufacturing cost of the mold.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of a plastic molded product using an injection mold according to the present invention.
FIG. 2 is a longitudinal sectional view at the time of molding an injection mold according to the present invention.
3 is a cross-sectional view taken along line AA in FIG.
4 is an operational state diagram of FIG. 2. FIG.
5 is an operational state diagram of FIG. 2. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fixed type | mold 2 Movable type | mold 3 Cavity 4 Horizontal extraction block 6 1st cylinder 10 Back surface 11 2nd cylinder 12 Lock block 13 Side surface

Claims (1)

The lateral disconnect block forming part of the molding surface with the mold opening direction providing a first cylinder for advancing and retracting movement in the non-parallel Naru direction, intervention from the orthogonal direction to the rear of the transverse disconnect block during molding of the lateral disconnect block A lock block for preventing retreat is provided by a second cylinder so as to be able to move forward and backward, and the back surface of the horizontal block is formed in a step shape, and the side surface of the lock block can be joined to the back surface of the horizontal block An injection mold characterized by being formed into a mold.

Images