JPH0643081B2 - Injection mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an injection molding die.

(B) Conventional technology When molding a product using an injection molding machine, after the molding is completed in the cavity of the mold, the gate cutting operation of cutting the gate part of the molded product with the mold closed is performed. An ejecting operation of ejecting the molded product after opening the mold is required. Generally, an injection molding machine is equipped with a drive device such as a hydraulic cylinder for eject operation. However, since a drive device for gate cut operation is not provided, conventionally, a hydraulic cylinder for gate cut operation was formed in the mold, or a hydraulic cylinder for gate cut operation was provided on the movable plate of the injection molding machine. Or, it constituted the drive device for gate cut.

(C) Problems to be Solved by the Invention As described above, conventionally, it is necessary to provide a die or injection molding machine with a hydraulic cylinder for gate cut operation, and to equip a hydraulic control device for controlling the hydraulic cylinder. Yes, the device was complicated. In addition to this, particularly in the case of the electric injection molding machine, since there is no hydraulic pressure source, there is a problem that a special hydraulic unit is required for the gate cutting operation. Although the electric injection molding machine has the advantage that it can mold clean molded products because it does not use a hydraulic device, it is not preferable to use a hydraulic device for gate cut operation. is there. The present invention aims to solve such problems.

(D) Means for Solving the Problems The present invention solves the above problems by enabling the gate cutting operation by the ejecting rod for the ejecting operation of the injection molding machine. That is, in the injection mold according to the present invention, the movable plate (10) is provided with the protruding plate (24), the sprue protruding pin (34), the gate cut member (52), the product protruding member (58), and the connection. A state switching mechanism (51) is provided and the cavity (1
4) The protrusion plate arranged on the side farthest from 4) is pushed by the protrusion rod (26) of the injection molding machine and is movable in the cavity direction and the spring (28).
Is pushed in a direction away from the cavity by the sprue, and the sprue projecting pin facing the sprue part (36) of the molded product (16) is connected to the projecting plate so as to always move integrally therewith, and moves toward the molded product. By doing so, the gate cutting member capable of cutting the gate portion (22) of the molded product can be switched by the connection state switching mechanism between a state in which the gate cutting member is movable in the axial direction integrally with the projecting plate and a state in which it is separated. The product projecting member, which is provided on the outer peripheral side of the gate cut member so as to be movable in the axial direction, is configured to receive the pressing force after the projecting plate moves from the initial stop position to the cavity side by a predetermined amount. ing. The reference numerals in parentheses indicate the corresponding members in the embodiments described later.

(E) Action In the case of the gate cut operation, the connection state switching mechanism is operated to the connection state side to connect the projecting plate and the gate cut member. In this state, when the protruding plate is advanced to the cavity side, the gate portion of the molded product is cut by the gate cutting member. Next, when the movable-side mold is retracted and the eject operation is performed after the mold is opened, the connection state switching mechanism is operated to the disconnecting side, and the projecting plate is advanced to the cavity side. As a result, the sprue projecting pin first projects the sprue portion, and then the projecting plate advances by a predetermined amount, and then the product projecting member starts to advance to project the product.

(F) Embodiment An embodiment of the present invention is shown in FIG. The injection mold comprises a movable mold 10 and a fixed mold 12.
The cavity 14 is formed on the mating surface of the movable mold 10 and the fixed mold 12, and thus the disk-shaped molded product 16 can be molded. The molten resin is filled in the cavity 14 from the sprue 20 at the center of the sprue bush 18 provided at the center of the fixed mold 12 side through the gate portion 22. The sprue bush 18 is movable in the axial direction. A plate 24 is provided movably in the axial direction so as to protrude to the farthest side from the cavity 14 of the movable mold 10. The ejection plate 24 moves to the right when the ejection rod 26 of the injection molding machine moves to the right in FIG. The protrusion plate 24 is provided with a spring 28 that acts on the protrusion plate 24 to counteract the force from the protrusion rod 26. When the protrusion rod 26 retracts, the force of the spring 28 causes the protrusion plate 24 to contact the stopper 29 at the initial stop position. It is returned (it is also possible to use, as the stopper 29, a mold mounting plate (not shown) for mounting the movable mold 10 to a movable plate (not shown). Further, a limit switch 30 capable of detecting that the projecting plate 24 is at the initial stop position is provided. The drive rod 3 is provided at the center of the protruding plate 24.
2 is fixed, and a sprue protruding pin 34 is provided on the tip end side of the drive rod 32. The drive rod 32 and the sprue protruding pin 34 are integrally formed. The tip of the sprue projecting pin 34 extends to a position where it comes into contact with the sprue portion 36 of the molded product 16. The drive rod 32 penetrates the hole 40 of the connecting plate 38. The connecting plate 38 is supported by the movable mold 10 so as to be movable in the axial direction, and is pressed by a spring 42 to an initial stop position where it contacts a stopper 44. An electromagnetic actuator 46 is provided on the connecting plate 38, and the electromagnetic actuator 46 can project the plunger 48 toward the center of the hole 40. This portion is shown enlarged in FIG. The drive rod 32 is provided with a plunger through hole 50 having a diameter slightly larger than the outer diameter of the plunger 48. When the connecting plate 38 and the projecting plate 24 are in the initial stop position, the position of the plunger 48 and the position of the through hole 50 are arranged to coincide with each other. Therefore, when the electromagnetic actuator 46 is operated in this state to cause the plunger 48 to project, the plunger 48 fits into the through hole 50. In this state, the connecting plate 38 projects in the axial direction together with the protruding plate 24. The connection plate 38, the electromagnetic actuator 46, the through hole 50 of the drive rod 32, and the like described above form a connection state switching mechanism 51. A hollow gate cut sleeve 52 is provided integrally with the connecting plate 38. The edge-shaped tip portion of the gate cut sleeve 52 faces the gate portion 22 of the molded product 16. As shown in FIG. 3, the gate cut sleeve 52 is provided with an axial elongated hole 54, and a push rod 56 described later penetrates through the elongated hole 54. The push rod 56 is fixed to the drive rod 32 in a direction orthogonal to the drive rod 32. A product projecting sleeve 58 is provided on the outer periphery of the gate cut sleeve 52. The right end surface of the product projecting sleeve 58 in FIG. 1 is arranged so as to come into contact with the molded product 16, while the left end surface is arranged so as to overlap the elongated hole 54 in the axial direction by a predetermined amount. Further, the product projecting sleeve 58 is provided with a flange portion 58a, to which the spring 59 acts a returning force to the left in FIG.

Next, the operation of this embodiment will be described. First, the movable side mold 10 is brought into close contact with the fixed side mold 12 to perform a mold opening mold clamping process in which a predetermined mold clamping force is applied, and then a cavity is passed from an injection device (not shown) through the sprue 20 and the gate portion 22. 14 is filled with molten resin. After maintaining the pressure for a predetermined time in this state, the cooling step is started. Simultaneously with the start of the cooling process, the electromagnetic actuator 46 operates to cause the plunger 48 to project. The plunger 48 fits into the through hole 50, and the connecting plate 38 projects so that it can move axially together with the plate 24. Next, the projecting rod 26 advances and moves the projecting plate 24 to the right in FIG. As a result, the protruding plate 24, the drive rod 32, the connecting plate 38, and the gate cut sleeve 52 are integrally moved to the right, and the gate portion 22 of the molded product 16 is cut. With the rightward movement of the gate cut sleeve 52, the sprue bushing 18 also moves by the same distance.
The amount of movement in this case is a dimension d until the connecting plate 38 is stopped, and this dimension d is set to a dimension at which the gate portion 22 can be cut. The product protruding sleeve 58 does not move during the operation. This is because the push rod 56 has not reached the position where it comes into contact with the product projecting sleeve 58 when the connecting plate 38 has moved by the dimension d. Immediately before the end of the cooling process, the projecting rod 26 retracts. Accordingly, the force of the springs 28 and 42 causes the protrusion plate 24, the drive rod 3
2, connecting plate 38, gate cut sleeve 52,
The sprue protruding pin 34 and the sprue bush 18 return to the initial stop position. This is limit switch 3
Detected by 0. At the same time, the electromagnetic actuator 46 operates to pull in the plunger 48. As a result, the connected state between the drive rod 32 and the connecting plate 38 is released. When the cooling process is completed, the mold opening process is performed next. That is, the movable mold 10 is the first
Move to the left in the figure. After the mold is opened, the rod 26 projects again and moves to the right in FIG. Along with this, the projecting plate 24 also moves to the right in FIG. 1, but since the connection between the drive rod 32 and the connecting plate 38 is released as described above, the drive rod 32, the sprue projecting pin Only 34 and push rod 56 move to the right. Since the tip of the sprue projecting pin 34 pushes the sprue part 36, this causes the sprue part 36 to project first. Then, when the drive rod 32 further advances, the push rod 56 contacts the left end surface of the product projecting sleeve 58 in FIG. 1 and moves it to the right. As a result, the ejecting operation of the product (the product 16 with the sprue portion 36 removed) is performed. After projecting the product,
When the ejecting rod 26 is retracted, the ejecting plate 24 and the member integral therewith are returned to the initial position by the spring 28, and the product ejecting sleeve 58 is returned to the initial position by the spring 59.

In this embodiment, the limit switch 30 is used to detect that the projecting plate 24 is in the initial setting position. However, any one of the projecting plate 24, the drive rod 32, the sprue projecting pin 34, the push rod 56 and the projecting rod 26 is used. A position detecting potentiometer or encoder may be provided on one of the members.

(G) Effect of the Invention As described above, according to the present invention, the connection state switching mechanism can switch between the state in which the gate cutting member is projected and connected to the plate side and the state in which the gate cutting member is disconnected, so that the injection is performed. Both the gate cutting operation and the ejecting operation can be performed by the ejecting rod for the ejecting operation of the molding machine, and it is not necessary to provide a dedicated hydraulic device for the gate cutting operation. In particular, in the case of an electric injection molding machine that is not equipped with a hydraulic power source, a hydraulic unit for gate cutting becomes unnecessary, and since hydraulic pressure is not used, it is advantageous to ensure the cleanliness of the product.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of the present invention, FIG. 2 is an enlarged view of a connection state switching mechanism, and FIG. 3 is a perspective view showing a portion of an elongated hole. 10 ... Movable mold, 12 ... Fixed mold, 14 ... Cavity, 16 ... Molded product, 22 ... Gate part, 24 ...
... projection plate, 26 ... projection rod, 28 ... spring, 32 ... driving rod, 34 ... sprue projection pin, 36 ... sprue portion, 38 ... coupling plate, 46 ... electromagnetic actuator, 48 ... Plunger, 50 ... Through hole, 51 ... Connection state switching mechanism, 52
...... Gate cut sleeve, 54 ...... elongated hole, 56 ...... push rod, 58 ...... product protruding sleeve.

Claims (1)

[Claims] 1. An injection molding die comprising a fixed side die and a movable side die, wherein the movable side die has a protruding plate, a sprue protruding pin,
A gate cut member, a product projecting member, and a connection state switching mechanism are provided, and the projecting plate arranged on the side farthest from the cavity is movable by the projecting rod of the injection molding machine in the cavity direction. The sprue protruding pin facing the sprue part of the molded product is pressed by the spring in the direction away from the cavity, and the sprue protruding pin is connected so as to always move integrally with the protruding plate, and by moving toward the molded product, the molded product The gate cut member that can cut the gate part is configured so that it can be switched between the state in which it is moved integrally with the protruding plate in the axial direction and the state in which it is separated by the connection state switching mechanism. The product protruding member that is provided on the outer peripheral side of the member so as to be movable in the axial direction Injection mold, characterized in that it is configured to receive a future pressure after moving a predetermined amount to the cavity side from the position.