WO2006054818A1

WO2006054818A1 - Hot runner valve gate opening and closing device of injection mold

Info

Publication number: WO2006054818A1
Application number: PCT/KR2005/001113
Authority: WO
Inventors: Jung Hooy Cho
Original assignee: Vmoltech
Priority date: 2004-11-16
Filing date: 2005-04-19
Publication date: 2006-05-26
Also published as: KR100483454B1

Abstract

Disclosed herein is an opening and closing apparatus for a hot runner valve gate in injection mold. The apparatus comprises a body 50 including a guide hole 52 for slider opened downwardly from a mid central axis and a guide hole 54 for push rod communicating with the slider guide hole; a nozzle 72 having a melt resin injection inlet 72a, and assembled into the body 50 by means of one axis via a guide bush 60 for valve pin interposed between the body and the nozzle; a push rod 90 adapted to be inserted into the hole 54 formed at the body 50, and connected to an actuator 80 so that it can move forward and backward; a slider 110 adapted to be inserted into the hole 52 formed at the body 50 so that it can move in an axial direction, and simultaneously is subjected to a force acting upwardly, which is produced from a spring 100 supported by the guide bush 60; and a valve pin 120 adapted to be inserted into the nozzle 70 and connected to the slider 110 via the guide bush 60 for valve pin so that it can control the flow of the melt resin introduced into the nozzle 70 via the guide bush 60 and the body 50 according to the operation direction of the actuator 80 by opening and closing a resin inlet 72a.

Description

HOT RUNNER VALVE GATE OPENING AND CLOSING DEVICE

OF INJECTION MOLD

Technical Field The present invention relates to an opening and closing apparatus for a hot runner valve gate in injection mold, in particular to an opening and closing apparatus for a hot runner valve gate in injection mold in which disintegration and assembly property, removing of thermal expansion of a manifold, removing of cumulated tolerance of mold processing, length reduction of a valve pin, and facility of maintenance and repair of the mold can be maximized.

Background Art In general, an injection molding fabricates a mold product of a desired shape (for instance, a vehicle instrument panel, door side panel, and the like) by injecting melt resin into a mold. In this instance, a hot runner into which the melt resin flows is provided with an opening and closing apparatus for a valve gate determining the injection time of the melt resin. The opening and closing apparatus of the valve gate determines the injection time of the melt resin while it is opened simultaneously or successively depending on control type. In a conventional opening and closing apparatus for a valve gate, the hot melt resin which has been injected from the injection molding is distributed and supplied into a nozzle via a manifold, and an outlet of the nozzle is opened and closed while upwardly and downwardly moving the valve pin, which is located within the nozzle, along with a cylinder provided at an upper clamping plate, wherein the valve pin has a construction linearly connected to the cylinder through a middle manifold, the manifold being located between the upper clamping plate and a lower hold plate and the cylinder, and the cylinder being arranged linearly with the valve pin.

According to this construction of the opening and closing apparatus of the valve gate, the hot melt resin is supplied into the nozzle via the manifold along an operation pin, and the outlet of the nozzle is opened and closed by the upward and downward operation of the valve pin based on the control of the cylinder operation.

The conventional opening and closing apparatus for the valve gate described above includes following problems.

First, Disintegration and assembly of the parts constructing the apparatus is not easy. As the cylinder and the valve pin are associated with each other in linear relationship and the valve pin is assembled through the manifold, the cylinder and the valve pin should be disintegrated so as to avoid hindrance of the valve pin at the time of disintegration of the manifold, and the surrounding related parts should also be disintegrated sequentially, to result in difficulty of the disintegration and assembly.

Second, when the manifold is thermal expanded, the valve pin is located at a passage of the manifold through which the hot melt resin passes to urge the valve pin toward any one side to produce deformation to result in faulty operation of the valve pin.

Third, when tolerance of assembly occurs owing to the arrangement of the cylinder at the clamping plate, operation fault of the valve pin is produced by the eccentricity of the operation axis thereof.

Furthermore, when the injection molding is performed for a long time, since the length of the valve pin should be made as long as the thickness of the upper clamping plate and the manifold so that the valve pin can be connected to the cylinder via the manifold, deformation is easily occurred due to heat and the function of an o-ring blocking outflow of the air supplied into the cylinder will be deprived. Especially, the manifold should be made large in case of a large mold (more than 650 tons) , however, in this instance, the valve pin operates disorderly due to increase of the thermal expansion in the manifold.

Finally, the fabrication process is made long and the fabrication cost arises, because the cylinder should be incorporated into the upper clamping plate.

As described above, in case of the valve gate system applied to the conventional injection mold, as the manifold has been arranged at the mid of the valve pin to make the length of the valve pin longer, and because the cylinder should be arranged in linear relationship with the valve pin at a different clamping plate, the assembly tolerance should be very minute and faulty operation of the valve pin is produced because the thermal expanded manifold deforms the valve pin. Therefore, disorder occurs in the opening and closing of the gate at the time of sequential control, to form bordering surface of product or to be unable to remove gas clustering to result in increase of badness ratio of the injection molded products.

Disclosure of Invention

Accordingly, the present invention has been made to overcome above-mentioned problems arising from prior technologies, and the object of the present invention is to provide an opening and closing apparatus for a hot runner valve gate in injection mold, in which reduction in the length of a valve pin can be accomplished by arranging the valve pin so that it is not interfered with a manifold, the assembly accuracy can be less affected by arranging a cylinder so that it is not located to be in linear relationship with the valve pin, and it is possible to accomplish accuracy and smoothness of the operation in the valve pin, as forces produced from thermal expansion of the manifold can not affect the valve pin, in spite of the long operation.

To accomplish above objects of the present invention, there is provided an opening and closing apparatus for a hot runner valve gate in an injection mold, the apparatus including: a body 50 including a guide hole 52 for slider opened downwardly from a mid central axis and a guide hole 54 for push rod communicating with the slider guide hole; a nozzle 72 having a melt resin injection inlet 72a, and assembled into the body 50 by means of one axis via a guide bush 60 for valve pin interposed between the body and the nozzle; a push rod 90 adapted to be inserted into the hole 54 formed at the body 50, and connected to an actuator 80 so that it can move forward and backward; a slider 110 adapted to be inserted into the hole 52 formed at the body 50 so that it can move in an axial direction, and simultaneously is subjected to a force acting upwardly, which is produced from a spring 100 supported by the guide bush 60; and a valve pin 120 adapted to be inserted into the nozzle 70 and connected to the slider 110 via the guide bush 60 for valve pin so that it can control the flow of the melt resin introduced into the nozzle 70 via the guide bush 60 and the body 50 according to the operation direction of the actuator 80 by opening and closing a resin inlet 72a.

Furthermore, the push rod 90 and the slider 110 may be arranged perpendicular to each other so that they are in contact with each other at inclined surfaces 90a, 11a thereof, and a plurality of rollers 92 are provided at the inclined surface 90a in the push rod 90 side.

Also, the slider 110 is provided with surface cut portion 110b extending flat from the inclined surface 110a. Meanwhile, the slider 110 may be provided with a plurality of steel balls 112 moved in a rolling manner with them being in contact with the guide hole 52 for slider in the body 50 side at the outer peripheral surface thereof.

In addition, the slider 110 may be preferably constructed to move upwardly and downwardly by means of a guide pin 56 pressingly inserted into an inner peripheral surface of the guide hole 52 at the body side.

According to the present invention, the actuator 80 may be selected from an air cylinder, a servo-motor, and a geared motor.

Also, the body 50 may be further attached at an upper surface thereof with a manifold 200 for distributing the melt resin into the body 50.

Furthermore, the manifold 200 has embedded therein at least one heater 201 having a rectangular cross-section.

The above object and other object of the present invention, particular advantages and novel features of the present invention will be made apparent from the following detailed description of the preferred embodiment in connection with the appended drawings.

Brief Description of Drawings FIG. 1 is an assembly cross-sectional view of an opening and closing apparatus for a valve gate according to a preferred embodiment of the present invention, showing an opened state of the valve,-

FIG. 2 is an assembly cross-sectional view of an opening and closing apparatus for a valve gate according to a preferred embodiment of the present invention, showing a closed state of the valve;

FIG. 3 is an exploded perspective view showing primary portion of the present invention; FIG. 4 is an assembly cross-sectional view taken along line A - A of FIG. 1;

FIG. 5 is a front cross-sectional view showing a slider incorporating the present invention; and

FIG. 6 is a view showing one side of FIG. 5.

Best Mode for Carrying Out the Invention

Preferred embodiment of the opening and closing apparatus for the valve gate in injection mold of the present invention will now be described in detail with reference to the appended drawings below.

FIG. 1 and FIG. 2 are assembly cross-sectional views of an opening and closing apparatus for a valve gate according to a preferred embodiment of the present invention, showing respectively opened state and closed state of the valve, FIG. 3 is an exploded perspective view showing primary portion of the present invention, FIG. 4 is an assembly cross-sectional view taken along line A - A of PIG. 1, FIG. 5 is a front cross-sectional view showing a slider incorporating the present invention, and FIG. 6 is a view showing one side of FIG. 5. Now, as shown in FIG. 1, according to a preferred embodiment of the present invention, a valve pin 120 is constructed to locate below a manifold 200, and an actuator 80 for operating the valve pin 120 is arranged at upper side of the valve pin 120 in the vertical direction with regard to the valve pin 120.

Accordingly, length of the valve pin 120 is reduced by a height L identical to a thickness of an upper clamping plate added to the manifold 200 by locating the manifold 200 above the valve pin 120, and fabricating process is simplified by removing the conventional cylinder from the clamping plate 210, and faulty operation of the valve pin 120 can be prevented in spite an occurrence of assembly tolerance.

A cylindrical body 50 is also provided below the manifold 200.

Furthermore, The body 50 includes a slider guide hole 52 opened downwardly from a mid central axis, a push rod guide hole 54 communicating with the guide hole 52 in a vertical direction, and a plurality of guide pins 56 arranged at predetermined angle in the longitudinal direction and pressingly inserted into an inner peripheral surface of the guide hole 52. In this instance, a pair of guide holes 54 are formed to pass through the body so as to reduce assembly time by assembling the slider 110 from both sides.

Also, a nozzle 72 is arranged below the body 50 for injecting the melt resin into a mold (not shown) , and a valve pin guide bush 60 is arranged between the body 50 and the nozzle 70 so that the melt resin inflowed along the resin passage P2 of the body 50 can be inflowed into the nozzle 70. The manifold 200, the body 50, and the valve pin guide bush 60 are assembled by means of a bolt 66.

The nozzle 70 is provided with a nozzle tip 72 below central axis thereof, and a resin inlet 72a formed at the nozzle tip 72 can be opened and closed by a conical outer peripheral surface formed at an end of the valve pin 120.

The push rod 90, which is inserted into the guide hole 54 formed at the body 50, is connected to an actuator 90 and moves forward and backward by the guide of the push rod guide hole 54. In the present embodiment of the present invention, the actuator 80 can be constructed of an air cylinder, however, it can be selected from a servo-motor or a geared motor.

Also, the actuator 80 according to the present embodiment comprises a cylinder housing 82 mounted at a hold plate 220, and a piston 84 mounted inside the cylinder housing 82 so that it can move slidably, and make the push rod 90 advance and retract along the direction of the air pressure connected to air inlet and air outlet ports 220a, 220b. The slider 110 is made to move upwardly and downwardly in association with the advance and retract movements of the push rod 90.

The slider 110 is inserted into the slider guide hole 52 formed at the body 50 so that it can move in the axial direction of the body 50, and at the same time, it is subjected to forces urging upwardly, the forces produced from a spring 100 supported by a valve pin guide bush 60.

The push rod 90 and the slider 110 are arranged perpendicular to each other so that they are in contact with each other at inclined surfaces 90a, 110a thereof, and a plurality of rollers 92 are provided at the inclined surface 90a in the push rod 90 side. Also, a surface cut portion 110b is provided at the slider 110 to extend in flat from the inclined surface 110a. The surface cut portion 110b is formed to reduce force produced from the slider 110 and acting on a wall surface of the slider guide hole 52, when the slider 110 moves downward by means of the operation of the push rod 90.

In this instance, the slider 110 can be preferably provided at the outer peripheral surface thereof with a plurality of steel balls 112 moved in a rolling manner with them being in contact with the guide hole 52 for slider in the body 50 side.

The valve pin 120 is inserted into the nozzle 70 and connected to the slider 110 via the valve pin guide bush 60. The valve pin 120 is configured to open and close the resin inlet 72a according to the operation direction of the actuator 80.

Meanwhile, a plurality of resin injection passages Pl,

P2, P3 are defined to penetrate the body 50 and the valve pin guide bush 60, and to communicate with a central axis of the nozzle 70 thereby to be connected to the injection inlet 72a of the nozzle tip 72.

Also, a band heater 132 is mounted at an outer peripheral edge of the valve pin guide bush 60 and the body 50 as heater means surrounding the resin injection passages

Pl, P2, P3, and a coil heater 130 is mounted at an outer peripheral surface of the nozzle 70.

Furthermore, the manifold 200 has embedded therein a pair of heaters 201 having a rectangular cross-section.

Now, the operation of the opening and closing apparatus for a valve gate in injection mold according to the preferred embodiment of the present invention will be described in detail below.

First of all, when the actuator 80 is located at the retracted position as shown in FIG. 1, the slider 110 is located at the advanced position by the expanding force of the spring 100, and the valve associated with the slider 110 is advanced to result in opening of the resin injection inlet 72a of the nozzle 70.

In this instance, the melt resin injected from an injection molding (not shown) into the manifold 200 is injected into a mold (not shown) via the opened injection inlet 72a after passing through the resin injection passages Pl, P2, and P3 in sequence.

Then, when the piston mounted within the cylinder is advanced by means of the air pressure, the push rod 90 connected to the piston rod 84a moves linearly in association with the movement of the piston, and at the same time, the slider 110 which is contacted with the push rod 90 at the inclined surface 90a, 110a, and the valve pin 120 which is connected to the slider 110 move downward to result in closing of the injection inlet 72a of the nozzle

70 thereby blocking the injection of the melt resin (see

FIG. 2) .

In this instance, the push rod 90 can smoothly operate by pressing the inclined surface of the slider 110 via the roller 92. Thereafter, when the actuator 80 is located at the retracted position again by the air pressure of the port 220b side, the slider 110 is also moved to the advanced position by the expanding force of the spring 100, and the valve associated with the slider 110 is moved in advance to result in opening of the resin injection inlet 72a of the nozzle 70 thereby allowing the melt resin to be injected.

As described above, operation control of the present apparatus can be accomplished by the upward and downward movement of the valve pin 120 according to the operation direction of the actuator 80 to result in opening and closing of the resin injection inlet 72a thereby allowing injection or blocking of the melt resin.

According to the opening and closing apparatus for the hot runner valve gate for injection mold of the present invention which is constructed and operated as described above, as the nozzle 70 has been assembled to the body 50 to which the valve pin 120 and the guide bush 60 are mounted by means of the bolt 66 clamping the manifold 200, it is easy to disintegrate and assemble the parts of the opening and closing apparatus for the hot runner valve gate of the present invention.

Also, as the valve pin 120 is located to avoid the manifold 200 through which the hot melt resin passes, the valve pin 120 does not deform in spite of the thermal expansion of the manifold 200. As a result, faulty operation of the valve pin 120 does not occur.

Furthermore, as the actuator 80 is not assembled to the clamping plate 210, the operation of the valve pin 120 is not affected in spite of the occurrence of the assembly tolerance. In addition, as the valve pin 120 is mounted without the intervention of the manifold 200, the length of the valve pin 120 is reduced by the height of the manifold 200 so that deformations, which arise from heat cumulated at the long term operation and from the resin pressure produced at the time of injecting melt resin, can be prevented.

According to the present invention, because the actuator 80 is not incorporated into the clamping plate 210, it is possible to remove air leakage arising from providing a plurality of o-rings in the cylinder, and fabrication process can be reduced to result in the reduction of the fabrication costs.

As described above, although the present invention has been described with regard to the limited embodiments and the appended drawings, various changes and modifications can be made without departing from the scope and spirit of the present invention by those peoples skilled in the relevant art.

Industrial Applicability

According to the opening and closing apparatus for the hot runner valve gate in injection mold of the present invention described as above and shown in the drawings, reduction in the length of the valve pin can be accomplished by arranging the valve pin so that it can avoid the manifold, and the assembly accuracy can be less affected by arranging a cylinder so that it is not located to be in linear relationship with the valve pin. Further, it is possible to accomplish accuracy and smoothness of the operation of the valve pin, as forces produced from thermal expansion of the manifold cannot affect the valve pin, in spite of the long-term operation.

In addition, the opening and closing of the resin injection inlet can be performed stably and reliably at the time of sequence control of the apparatus, to reduce ratio of faulty products so that good mold products can be obtained.

Claims

1. An opening and closing apparatus for a hot runner valve gate in an injection mold, the apparatus comprising: a body 50 including a guide hole 52 for slider opened downwardly from a mid central axis and a guide hole 54 for push rod communicating with the slider guide hole; a nozzle 72 having a melt resin injection inlet 72a, and assembled into the body 50 by means of one axis via a guide bush 60 for valve pin interposed between the body and the nozzle; a push rod 90 adapted to be inserted into the hole 54 formed at the body 50, and connected to an actuator 80 so that it can move forward and backward; a slider 110 adapted to be inserted into the hole 52 formed at the body 50 so that it can move in an axial direction, and simultaneously is subjected to a force acting upwardly, which is produced from a spring 100 supported by the guide bush 60; and a valve pin 120 adapted to be inserted into the nozzle 70 and connected to the slider 110 via the guide bush 60 for valve pin so that it can control the flow of the melt resin introduced into the nozzle 70 via the guide bush 60 and the body 50 according to the operation direction of the actuator 80 by opening and closing a resin inlet 72a.

2. The apparatus according to claim 1, wherein the push rod 90 and the slider 110 are arranged perpendicular to each other so that they are in contact with each other at inclined surfaces 90a, 11a thereof, and a plurality of rollers 92 are provided at the inclined surface 90a in the push rod 90 side.

3. The apparatus according to claim 1 or 2, wherein the slider 110 is provided with surface cut portion 110b extending flat from the inclined surface 110a.

4. The apparatus according to claim 1 or 2, wherein the slider 110 is provided with a plurality of steel balls 112 moved in a rolling manner with them being in contact with the guide hole 52 for slider in the body 50 side at the outer peripheral surface thereof.

5. The apparatus according to claim 1 or 2, wherein the slider 110 is preferably constructed to move upwardly and downwardly by means of a guide pin 56 pressingly inserted into an inner peripheral surface of the guide hole 52 at the body side.

6. The apparatus according to claim 1, wherein the actuator 80 is selected from an air cylinder, a servo-motor and a geared motor.

7. The apparatus according to claim 1, wherein the body 50 is further attached at an upper surface thereof with a manifold 200 for distributing the melt resin into the body 50.

8. The apparatus according to claim 1 or claim 2, wherein the manifold 200 has embedded therein at least one heater 201 having a rectangular cross-section.