JPH0425302Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an improvement of a mold device for injection molding a resin molded product.

(Prior art) Generally, in order to injection mold a resin molded product, the first
The mold and the second mold are provided so as to be able to come into contact with and separate from each other,
A cavity formed between the mating surfaces of both molds is injected and filled with molten molding material via a runner and a gate.

(Problems to be Solved by the Invention) As for such an injection molding mold device, in a previous application, the applicant proposed a method in which, when moving forward, a first molding mold and a lower molding device constituting an upper mold are configured. A slide block constituting a runner and a gate between the second mold and the first mold is provided on the second mold side so as to be movable back and forth in a direction intersecting the direction of relative movement of the two molds. A slide cam is provided so as to be movable back and forth in a direction intersecting the direction of movement of the slide block. By moving the slide cam forward during injection molding, the slide block is moved to the second mold side and the front end surface of the slide block is brought into pressure contact with the side surface of the second mold.Then, the molten molding material is passed through the runner and gate into the cavity. After injection and filling, the molten molding material in the cavity is cooled and solidified to form a resin molded product. On the other hand, after injection molding, by retracting the slide cam, the slide block is moved in a direction away from the second mold, and the resin in the runner part is separated from the resin molded product by separating the cavity and gate. (See the specification and drawings of Utility Application No. 1988-88153).

By the way, generally speaking, when a gap is created during injection molding between the front end surface of the slide block and the side surface of the second mold with which the front end surface of the slide block is pressed, the molten molding material infiltrates this gap and causes burrs on the injection molded product. To prevent this from occurring, both contact surfaces are formed into straight vertical surfaces so that they are in complete contact with each other without any gaps.

However, it is usually difficult to form this straight vertical surface without any gaps when the tip end surface of the slide block is in pressure connection with the side surface of the second mold due to the machining accuracy. If it is not finished, a gap will be created between the tip end surface of the slide block and the side surface of the second mold during injection molding, and the molten molding material will enter this gap. When the molten molding material intrudes into the gap between the slide block tip surface and the second mold side surface in this way, the slide block tip surface and the second mold side surface are formed into straight vertical surfaces as described above. Therefore, the molten molding material that has entered the gap moves downward along the vertical surface of the straight member and enters the sliding surface of the slide block, and the resin intrusion into the slide surface hinders the sliding operation of the slide block. This may cause a problem that molding may become impossible.

The present invention has been made in view of the above, and its purpose is to provide a runner and a gate between the first mold and the second mold in contact with the first mold and the second mold during advancement as described above. By specifying the shapes of the contact surfaces between the slide block and the second mold, it is possible to prevent molten molding material from penetrating into the gap created between the two contact surfaces during injection molding due to problems such as processing accuracy. However, this infiltrated molten molding material does not infiltrate into the sliding surface of the slide block, and as a result, the sliding operation of the slide block is performed normally without any hindrance, and the sliding function of the slide block is thereby maintained. The object is to reliably prevent the occurrence of a situation in which molding is impossible due to a failure.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention has a first mold and a second mold that are provided so as to be able to come into contact with and separate from each other. A mold device for injection molding that molds a resin molded product by injecting and filling a molten molding material into a cavity formed between mating surfaces of a mold through a runner and a gate, and when moving forward, the first and second molding A slide block that is in contact with the mold and constitutes the runner and gate between the first mold and the mold is provided on the second mold side so as to be movable back and forth in a direction intersecting the direction of relative movement of both molds. Further, a slide cam is provided so as to be movable back and forth in a direction intersecting the direction of movement of the slide block, the slide cam urging the slide block toward the forward side by sliding its slope surface against the slope surface of the slide block when the slide block moves forward.
Further, a stepped portion extending in the moving direction of the slide block is formed on a contact surface of the slide block with the second mold and a contact surface of the second mold that contacts the contact surface.

(Function) With the above configuration, in the present invention, during injection molding,
The slide block provided on the second mold side is
The first movement is caused by the forward movement of the slide cam provided in the direction intersecting the movement direction of the slide block.
and the second mold is moved forward in a direction intersecting the relative movement direction of the second mold, whereby a runner and a gate are formed between the slide block and the first mold, and the molten molding material is passed through the runner and gate. is injected into the cavity.

In this case, a stepped portion extending in the moving direction of the slide block is formed on the contact surface of the slide block with the second mold and the contact surface of the second mold that contacts the contact surface. Even if the molten molding material intrudes into the gap created between the two contact surfaces during injection molding due to processing precision problems, the infiltrated molten molding material is prevented from further infiltration by the step part, and the above-mentioned The infiltration does not reach the sliding surface of the slide block, and as a result, the sliding operation of the slide block is performed normally without any hindrance, thereby preventing the occurrence of a situation in which molding cannot be performed due to failure of the sliding function of the slide block. This will definitely be prevented.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 shows an injection mold device according to an embodiment of the present invention applied to injection molding of a resin bumper for an automobile, in which 1 is a first mold forming an upper mold as a fixed mold; is supported vertically on the base 3, and constitutes a lower mold as a movable mold that is vertically movable toward and away from the first molding mold 1.
The mold 4 can move forward and backward in the direction intersecting the moving direction of the second mold 2, that is, in the horizontal direction, through spacers 5, 5 (only one is shown in the figure) on the upper side of the second mold 2. The first mold 1 is provided with a sprue 6 extending in the vertical direction at a predetermined position of the first mold 1, and the sprue 6 is connected to an injection molding machine (not shown) via a passage 7. The molten molding material A ₁ (shown in FIG. 2) made of plastic, such as polypropylene, is injected from the nozzle of the injection molding machine and introduced into the sprue 6 through the passage 7. It is done like this.

On the other hand, when the slide block 4 is moved forward (horizontal movement to the left in the figure) by the advance (upward movement in the figure) of the slide cam 12, which will be described later, the lower surface of the first mold 1 and the second mold Type 2
It is recessed so as to form a runner 8 and a gate 9 between it and the first mold 1 in contact with the side surface thereof, and when the slide block 4 moves forward, the melt molded material is introduced into the sprue 6 of the first mold 1. The material A ₁ is injected and filled into a cavity 10 formed between the mating surfaces of the first mold 1 and the second mold 2 through the runner 8 and gate 9.

Further, the slide block 4 is formed with a through hole 11 having an outwardly inclined inclined surface 11a, and the upper half of the slide cam 12 has an inclined surface 12a corresponding to the inclined surface 11a. is inserted and supported so that it can move forward and backward in the vertical direction. The lower end of the slide cam 12 is fixed to the tip of a piston rod 13a of a hydraulic cylinder 13 supported by the base 3, and when the hydraulic cylinder 13 is extended, the slide cam 12
By moving upward, the inclined surface 1
2a is slid on the inclined surface 11a of the through hole 11 of the slide block 4, and the slide block 4 is moved forward from the state shown by the phantom line in FIG. 2 to the state shown by the solid line. In this state, the sprue 6 of the first mold 1 passes through the runner 8 and the gate 9 to the cavity 1.
The molten molding material A ₁ introduced into the sprue 6 from the nozzle of the injection molding machine is injected and filled into the cavity 10 through the runner 8 and the gate 9, and the first mold 1 and the second mold The cavity 10 is cooled by the cooling action of the cooling water circulating through the cooling passages 14, 14 extending around each of the molds 2.
By cooling and solidifying the molten molding material A ₁ inside, a bumper molded product A ₂ is molded. In this state, the upper end of the slide cam 12 is engaged with the engagement groove 1a formed in the lower surface of the first mold 1, and this engagement action causes the slide block 4 to
It regulates the backward movement of.

On the other hand, by moving the slide cam 12 downward by the contraction operation of the fluid pressure cylinder 13, the inclined surface 12a thereof is slid on the inclined surface 11a of the through hole 11 of the slide block 4 in the opposite direction. , the slide block 4 is moved backward from the state shown by the solid line in FIG. is being done. In this state, the upper end of the slide cam 12 is disengaged from the engagement groove 1a of the first mold 1, allowing the slide block 4 to move backward, and this backward movement causes the runner 8 portion to solidify. The resin A ₃ is separated from the bumper molded product A ₂ by separating the cavity 10 and the gate 9.

Further, within the second mold 2, a cylindrical ejector pin 16 extending in the vertical direction is supported by a guide rod 17 fitted therein so as to be slidable in the vertical direction, and the tip of the guide rod 17 is connected to the upper end of the ejector pin 16. The boss part a ₂ of the bumper molded product A ₂ is made to protrude further upward and its tip is held at its tip.
At the same time, after the mold is opened, the ejector pin 16 is moved upward by a drive means (not shown), so that the bumper molded product A ₂ is pushed upward and removed from the second mold 2. On the other hand, another ejector pin 18 extending in the vertical direction is fitted and supported in the slide block 4 so as to be slidable in the vertical direction. The resin A ₃ in the runner 8 portion after molding A ₂ is pushed upward and separated from the runner 8 by moving the ejector pin 18 upward by a drive means (not shown) after the mold is opened.

Furthermore, as a feature of the present invention, the lower half of the forward end surface of the slide block 4 is cut out to form a stepped portion 4a, as shown in enlarged detail in FIG. A step portion 2a is formed on the side surface of the second mold 2 corresponding to the slide block 4 side, with its lower half protruding so as to engage with the step portion 4a of the slide block 4. That is, the contact surface of the slide block 4 with the second mold 2 and the second mold 2 that contacts the contact surface.
Step portions 4a, 2a extending in the direction of movement of the slide block 4 are formed on the contact surfaces thereof.

Further, on the side of the fluid pressure cylinder 13, as shown in enlarged detail in FIG.
9 and 20 are arranged, and the upper end of a rod member 21 extending in the vertical direction is connected to the piston rod 13a of the hydraulic cylinder 13 via a connecting member 22. The bulging contact portion 21a that the detection portion 19a of the upper limit switch 19 contacts when the limit switches 19, 20 are extended, and the lower limit switch 20 of the limit switches 19, 20 when the fluid pressure cylinder 13 is retracted. A bulging contact portion 21 that the detection portion 20a comes into contact with
b are arranged and fixed at predetermined intervals. Then, the slide cam 12 moves upward due to the extension operation of the fluid pressure cylinder 13, and this upward movement causes the stepped portion 4a of the slide block 4, which has been moved forward in the horizontal direction, to contact the stepped portion 2a of the second mold 2. When the engagement state is securely in the normal engagement state, the upper contact portion 21a of the rod member 21 contacts the detection portion 19a of the upper limit switch 19 to notify this, while the contraction of the fluid pressure cylinder 13 Due to the operation, the slide cam 12 moves downward, and this downward movement causes the second step portion 4a of the slide block 4 to move backward in the horizontal direction.
When the engagement state of the mold 2 with the stepped portion 2a is released and the mold 2 moves backward by the normal backward movement amount, the lower contact portion 21b of the rod member 21 contacts the detection portion 20a of the lower limit switch 20 to notify this fact. It is done like this. On the other hand, when the contact portion 21a is not in contact with the detection portion 19a of the upper limit switch 19 due to the extension operation of the fluid pressure cylinder 13, the step portion 4a of the slide block 4 is connected to the step portion of the second mold 2. 2a is not properly engaged, and the fluid pressure cylinder 1
If the contact portion 21b is not in contact with the detection portion 20a of the lower limit switch 20 due to the contraction operation in step 3, it is determined that the slide block 4 has not slid to the normal retreat position, and the fluid pressure cylinder 13 Then, the operation of the molding equipment such as the injection molding machine is stopped, or an alarm device is activated to notify the operator of this fact.

Next, a case where an automobile bumper is injection molded using the injection mold device according to the above embodiment will be described.

(1) First, the second mold 2 is moved upward, its mating surface is brought into contact with the mating surface of the first mold 1, and the mold is clamped. Then, the fluid pressure cylinder 13 is extended and the slide block is closed. 4 is moved forward in the horizontal direction by upward movement of the slide cam 12, which causes the stepped portion 4a of the slide block 4 to
is engaged with the stepped portion 2a of the second mold 2, and the sprue 6 of the first mold 1 is communicated with the cavity 10 via the runner 8 and gate 9. Note that cooling water is circulated through the cooling passages 14, 14 of each of the first mold 1 and the second mold 2, so that the cavity 10 portion constituted by both the molds 1, 2 is cooled to a predetermined temperature. ing.

(2) In this state, the injection molding machine is operated and the molten molding material A ₁ is introduced from the nozzle into the sprue 6 through the passage 7, and the molten molding material A ₁ in the sprue 6 is The injection pressure of the molding machine injects and fills the cavity 10 through the runner 8 and gate 9, and after a predetermined period of time, both cooling passages 14, 1 are filled.
The bumper molded product A2 is cooled and solidified by the cooling action of the cooling water circulating through the bumper molded product _A2 .

(3) Next, the fluid pressure cylinder 13 is contracted to move the slide block 4 to the slide cam 1.
2. Move backward by moving downward. Due to this backward movement of the slide block 4, the gate 9
The section is cut, and this results in the above cavity 1.
The bumper molded product A ₂ in 0 and the resin A ₃ solidified in the runner 8 section are separated.

(4) After that, the second mold 2 is moved downward to open the mold, and the ejector pin 16 on the second mold 2 side is moved upward to remove the bumper molded product A ₂ from the second mold 2. 1
6 and push it upward to separate it from the second mold 2, and move the ejector pin 18 on the slide block 4 side upwards to release the solidified resin A ₃ from the runner 8 and gate 9 into these parts. The ejector pin 18 is also pushed upward to separate it from the runner 8 and gate 9.

Therefore, in the above embodiment, when the slide block 4 is moved forward in the horizontal direction by the expansion operation of the fluid pressure cylinder 13 during injection molding, the step portion 4a of the slide block 4 is brought into contact with the step portion 2a of the second mold 2. Because they are designed to engage, a gap is created between the two contact surfaces during injection molding due to problems such as the machining and finishing accuracy of the contact surfaces of the slide block 4 and the second mold 2. Even if the molten molding material A ₁ infiltrates, the infiltrated molten molding material A ₁ is prevented from further infiltration by the stepped portion 2 a of the second mold 2 and infiltrates into the sliding surface of the slide block 4 . As a result, the sliding operation of the slide block 4 is performed normally without any hindrance, and it is therefore possible to reliably prevent the occurrence of a situation in which molding cannot be performed due to failure of the sliding function of the slide block 4.

In the above embodiment, the step portion 4a of the slide block 4 is formed by cutting out the lower half of the front end surface of the slide block 4, while the step portion 2a of the second mold 2 is formed by cutting out the lower half of the front end surface of the slide block 4. Although the upper half portion is formed by cutting out the upper half portion, the step portion 4a of the slide block 4 is not limited thereto.
The main point is that the step part 2a of the second mold 2 is formed by cutting out the lower half of the side surface of the second mold 2. If the structure is such that it is possible to form a blocking part such as a horizontal surface part to prevent the melt molding material A ₁ from penetrating into the sliding surface of the slide block 4 from the respective contact surfaces of the slide block 4 and the second mold 2, such means can be used. I don't care.

Further, in the above embodiment, the slide block 4 is moved by the slide cam 12 which moves up and down by the expansion and contraction operation of the fluid pressure cylinder 13, but the present invention is not limited to this. It is also possible to provide a separate driving means such as a fluid pressure cylinder and use this to cause the sliding movement.

Further, in the above embodiment, the molded product formed by injection molding is a bumper for an automobile, but it goes without saying that the molded product is not limited to this.

(Effect of the invention) As explained above, according to the invention, the molten molding material is injected into the cavity formed between the mating surfaces of the first mold and the second mold, which are provided so as to be able to come into contact with and separate from each other. a slide block that constitutes a runner and a gate with the first mold for filling;
Since a stepped portion extending in the advancing and retreating direction of the slide block is formed on each contact surface with the second mold, the above-mentioned step portions are formed during injection molding due to problems such as machining and finishing accuracy of the contact surfaces of the slide block and the second mold. Even if a gap is created between both contact surfaces and the molten molding material infiltrates into this gap, the infiltration of the molten molding material into the sliding surface of the slide block will occur at the stepped portion of the second mold. It is possible to reliably prevent the occurrence of a situation in which molding is impossible due to failure of the sliding function of the slide block.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional front view of an injection molding mold device according to an embodiment of the present invention, Fig. 2 is an enlarged vertical sectional front view of the main part of the slide block portion, and Fig. 3 is a limit switch for detecting the amount of movement of the slide block. FIG. 3 is an enlarged side view showing the arrangement relationship. 1...First mold, 2...Second mold, 2a...
...Stepped part, 4...Slide block, 4a...Stepped part, 8...Runner, 9...Gate, 10...Cavity, 11a...Slanted surface, 12...Slide cam, 12a...Slanted surface, A ₁ ...melt molding material,
A ₂ ... Bumper molded product.

Claims (1)

[Scope of utility model registration request] A first mold and a second mold that are provided so as to be able to come into contact with and separate from each other.
In an injection mold device for molding a resin molded product by injecting and filling a molten molding material into a cavity formed between mating surfaces of the two molds through a runner and a gate, the above-mentioned The runner and gate are provided on the second mold side so as to be movable forward and backward in a direction intersecting the direction of relative movement of both molds, and are in contact with the first mold and the second mold when moving forward, and between the first mold and the first mold. a slide block that constitutes the slide block; and a slide cam that is provided so as to be movable back and forth in a direction intersecting the direction of movement of the slide block, and that biases the slide block toward the forward side by having its inclined surface come into sliding contact with the inclined surface of the slide block when moving forward. and a stepped portion extending in the moving direction of the slide block is formed on a contact surface of the slide block with the second mold and a contact surface of the second mold that contacts the contact surface. An injection mold device featuring: