JP2000343559A - Apparatus for preventing resin from drooling at apex of nozzle in injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a resin from drooling at the apex of an injection nozzle and to easily remove the resin stuck on the injection nozzle without putting an operator to trouble with hands. SOLUTION: A drooling-proof mechanism C provided in parallel on an injection unit to its heating cylinder 10 is constituted by fitting a rotary air actuator 18 at the apex of a working rod 15 of an air cylinder 16 for advancing and retreating and providing a closing member 20 rotating in the direction intersecting at right angles to the axial line of the heating cylinder 10 on the rotating shaft of the rotary air actuator 18. When molding work is started under a condition where the injection unit is at the retreating position, after the closing member 20 is advanced by operation of the air cylinder 16 for advancing and retreating, it is rotated from the retreating position by operation of the rotary air actuator 18 and is brought into contact with the apex side of an injection nozzle 9 to close the opening just before nozzle touch. It is possible thereby to prevent a resin from drooling from the injection nozzle 9 during measuring and to remove stuck resin on the injection nozzle 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin drooling prevention device for preventing resin dripping from the tip of an injection nozzle in an injection molding machine.

[0002]

2. Description of the Related Art In a molding operation using an injection molding machine, an injection unit is located at a rearmost position when molding is started. At this position, a first resin material is supplied to a heating cylinder, and a resin is injected from the tip of an injection nozzle. And measure the molten resin at the tip inside the heating cylinder. In addition, the injection nozzle is advanced for each shot to perform a nozzle touch, and after the end of the shot, the injection nozzle is retracted to shift to the next shot. The molten resin in the injection nozzle may adhere to and remain at the nozzle tip in a stringed state, or the resin may come out of the nozzle tip due to the residual pressure of the molten resin in the injection nozzle and adhere thereto.

[0003] As described above, when the nozzle touch operation is performed with the resin coming out of the tip of the injection nozzle remaining in the state of the resin dripping or stringing adhered thereto, the injection nozzle is pressed while crushing the adhering resin. Since the tip comes into contact with the mold, the tip of the injection nozzle and the sprue bush of the mold do not adhere to each other, and when the molten resin is injected, the resin comes out of the gap between the tip of the injection nozzle and the sprue bush of the mold. Leaks occur. For this reason, conventionally, an operator has used an appropriate tool to scrape and remove resin dripping attached to the tip of the injection nozzle immediately before touching the injection nozzle with the die.

[0004]

However, the above-mentioned work of removing the resin dripping not only requires labor, but also involves a problem that the work involves danger because it uses a high-temperature molten resin. In the case of nozzle touch molding, in which the injection nozzle is always in contact with the mold and molding is continued, the resin dripping may be removed only for the first shot. However, in the case of backward molding for each shot nozzle, resin dripping or stringing is performed for each shot. It is necessary to remove the resin that has been removed, but the removal operation must be performed frequently in accordance with the forward and backward movements of the injection unit, and this involves an even greater danger. For this reason, there has been a demand for an apparatus for preventing resin dripping from the nozzle tip by an appropriate mechanism and removing the adhered resin.

Accordingly, an object of the present invention is to provide an apparatus for preventing resin drooling at the tip of a nozzle in an injection molding machine which can prevent resin dripping from the tip of an injection nozzle during a nozzle touch operation. Another object of the present invention is to provide an injection molding method that can easily remove resin adhering to the tip of an injection nozzle in a state of resin dripping or stringing when the nozzle is retracted, without the need for labor of an operator. It is an object of the present invention to provide a device for preventing resin drooling at the tip of a nozzle in a machine.

[0006]

To achieve the above object, according to the present invention, there is provided an injection unit provided to be movable forward and backward with respect to a mold clamped by a mold clamping unit. In an injection molding machine that advances from a position to bring an injection nozzle of a heating cylinder into contact with the mold and inject the molten resin in the heating cylinder from the injection nozzle into the mold, the injection unit is heated from a retracted position. In the section until the injection nozzle of the cylinder reaches the advance position immediately before contacting the mold, the closing member moved from the standby position to the position in contact with the tip of the injection nozzle closes the opening of the injection nozzle. The mechanism is provided with a mechanism.

In the apparatus having the above structure, when the injection unit is located at the retracted position, the closing member of the drooling prevention mechanism moves from its standby position to a position where it comes into contact with the tip of the injection nozzle. Thus, the opening at the tip of the injection nozzle is closed. In this state, the resin material is supplied to the heating cylinder to measure the molten resin. When the metering is completed, the injection unit is advanced, and the injection nozzle of the heating cylinder is brought into contact with the mold clamped by the mold clamping unit to perform a nozzle touch operation. At that time, when the tip of the injection nozzle reaches the forward position immediately before contacting the mold, the closing member retreats to the standby position, so that the closing member does not hinder the nozzle touch operation, The nozzle touch operation is performed in a state where there is no resin dripping from the tip of the nozzle. Therefore, the sprue bush of the mold abutted by the nozzle touch operation and the tip of the injection nozzle are in close contact with each other without any gap, so that the molten resin does not leak out from the tip of the injection nozzle during injection.

In the apparatus according to the first aspect, the section from the retracted position of the injection unit to the advanced position immediately before the injection nozzle of the heating cylinder comes into contact with the mold is when the injection unit starts to advance from the retracted position. At the same time, it is possible to adopt a configuration that is determined by a set time of a timer for starting time measurement (claim 2). In this configuration, the timing at which the resin does not drool from the injection nozzle even when the closing member is retracted from the position for closing the opening of the injection nozzle to the standby position is set according to the set time of the timer.

In the apparatus according to the first or second aspect, the drooling prevention mechanism injects the closing member between a forward position corresponding to the distal end side of the injection nozzle and a standby position separated rearward from this position. A first actuator for reciprocating in a direction parallel to the axis of the nozzle, and the closing member separated from the position for closing the opening of the injection nozzle orthogonally to the axis of the injection nozzle in its advanced position to the side of the injection nozzle; A second actuator that reciprocates with the retracted position may be provided (claim 3).
According to this configuration, the reciprocating movement of the closing member between the position where the opening of the injection nozzle is closed and the standby position separated from the tip of the injection nozzle is smoothly and reliably performed by two operations.

[0010] In the apparatus according to the third aspect, the drooling preventing mechanism may be configured such that a second actuator is connected to an operating shaft of the first actuator (claim 4). Item 4. The retraction device according to Item 4, wherein the second actuator has a base end of the closing member connected to its operating shaft, and a distal end of the closing member is separated from the position for closing the opening of the injection nozzle and to the side of the injection nozzle. It can be configured as a rotary actuator that turns to and from a position (claim 5). According to these configurations, the device for reciprocating the closing member between the position where the opening of the injection nozzle is closed and the retracted position and between the retracted position and the standby position has a simple structure, and the installation space is simple. Can be easily implemented with a small size.

In the apparatus according to any one of the first to fifth aspects, a material having a high thermal conductivity is provided at a portion of the distal end portion of the closing member which closes the opening of the injection nozzle. The apparatus according to any one of claims 1 to 6, wherein the closing member is provided with a heat radiating mechanism (claim 7). According to these configurations, when the closing member closes the opening of the injection nozzle, the tip of the injection nozzle is radiated well by the material having a high thermal conductivity or the heat radiation mechanism in the closing member, and the temperature is reduced. Therefore, even if the closing member releases the opening of the injection nozzle just before the tip of the injection nozzle comes into contact with the mold, the temperature of the molten resin in the tip of the injection nozzle decreases and its fluidity decreases. The molten resin does not leak from the opening.

In the apparatus according to any one of claims 1 to 7, a portion of the distal end portion of the closing member that closes the opening of the injection nozzle is a front side that comes into contact with the distal end portion of the injection nozzle. And a cutter having a blade surface may be provided (claim 8). According to the device having this configuration, the cutter of the closing member easily cuts and removes the resin adhered to the tip of the injection nozzle, even if it is a thermosetting resin containing glass fiber.

In the apparatus according to any one of the first to eighth aspects, the injection unit may be configured to inject a thermosetting resin into a mold as a molten resin in a heating cylinder. (Claim 9). According to this configuration, the present invention can be easily applied to a thermosetting resin that is likely to be thermally cured and fixed to the tip of the injection nozzle.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 and 2, reference numeral 1 denotes an injection molding machine, which includes a vertical mold clamping unit A, a horizontal injection unit B, and a drooling prevention mechanism C. The mold clamping unit A is provided between a top plate (fixed plate) 4 and a base plate (end plate) 5 fixed to the upper and lower ends of four tie bars 3 erected on one side of the base 2. The movable platen 6 is moved up and down along the tie bar 3 by driving the toggle mechanism 7 with a drive device (not shown), and the mold K attached to the top plate 4 and the movable platen 6 is opened and closed and the mold is closed. It has become.

The injection unit B is installed on a gantry 8 erected on the other side of the base 2, and has a heating cylinder 10 provided with an injection nozzle 9 at the tip thereof, and an inside of the heating cylinder 10. And an operating mechanism 12 for driving an injection member (not shown) such as an injection screw inserted in the hopper 11, melting and kneading the resin material supplied from the hopper 11, measuring and injecting the resin material. Then, the injection nozzle 9 is directed toward the mold clamping unit A, and between the forward end position where the tip of the injection nozzle 9 contacts the sprue bush of the mold K and the retreat position most separated from the mold K. The operating mechanism section 12 is supported by a guide section of a base 13 fixed to the upper end of the gantry 8 so as to move forward and backward. The height position of the axis of the injection nozzle 9 (heating cylinder 10) coincides with the height position of the parting surface of the mold K clamped by the mold clamping unit A. At the front and rear ends of the base 13, switches E for detecting the movement of the injection unit B to the forward limit position and the retreat position, respectively.
5, E6 is attached.

Further, the drooling prevention mechanism C is
One side of the heating cylinder 10 is provided in front of the operating mechanism 12 of the injection unit B in parallel with the axis of the heating cylinder. As shown in detail in FIGS. 3 to 5, the drooling prevention mechanism C is attached to an upper end of a bracket 14 fixed to the front side of the operation mechanism section 12 by a bolt or the like, and an axis of an operation rod (operation axis) 15 is provided. Direction heating tube 1
And a connecting plate 17 fixed to the front end of the operating rod 15 with bolts or the like. The rotating shaft (operating shaft) Rotary air actuator (second actuator) arranged on extension of 15 axes
And a closing member 20 whose base end is fixed to a rotary plate 19 fixed to the front end of the rotary shaft of the rotary air actuator 18 by bolts or the like, and whose distal end pivots in a plane orthogonal to the axis of the heating cylinder 10. It has. The forward / backward traveling air cylinder 16 and the rotary air actuator 18 are provided with switches LS1 and LS2 for detecting the forward and backward movements of the operating rod 15, and the rotation of the rotary shaft to the rotation limit and the return to the origin. Switches LS3, LS4 to detect
Are respectively incorporated.

In the standby position where the operating rod 15 of the forward / backward moving air cylinder 16 has moved to the retreat limit, the rotation axis of the rotary air actuator 18 returns to the origin, and the closing member 20 moves in the radial direction (side) of the heating cylinder 10. In the retracted position that does not interfere with the heating cylinder 10 and the operating rod 15 of the forward / backward moving air cylinder 16 has moved to the forward limit (forward position corresponding to the tip end side of the injection nozzle 9).
Then, the back surface on the tip side of the closing member 20 (injection nozzle 9
Is located in a plane perpendicular to the axis of the heating cylinder 10 and in contact with the tip of the injection nozzle 9, and the closing member 20 is moved by the rotation axis of the rotary air actuator 18 from the origin to the rotation limit. The opening of the injection nozzle 9 is closed by pivoting from the retracted position to a position where it abuts on the tip of the injection nozzle 9, and the closing member 20 reversely pivots and returns to the retracted position by reversing the rotation axis to the origin. ing.

A material 20a having a high thermal conductivity, such as copper, is provided at a portion of the tip of the closing member 20 which closes the opening of the injection nozzle. Instead of the material 20a having a high thermal conductivity, a radiating fin or a radiating portion (radiating mechanism) for circulating cooling water is directly provided at the distal end of the closing member 20, or a radiating plate provided with the radiating portion is provided. May be attached. The portion that closes the opening of the injection nozzle may have a configuration in which a cutter 20c having a blade surface 20b is provided on the front side before reaching the tip of the injection nozzle. The connecting plate 17 has a pair of guide rods 21 which are guided at both ends thereof by a forward / reverse air cylinder 16 so as not to rotate around the axis of the operating rod 15.

Next, the configuration of the control device 22 for controlling the injection molding machine 1 will be described. In FIG. 6, reference numeral 23 denotes a control arithmetic unit that stores an operation program of the injection molding machine 1 and controls operations of the mold clamping unit A, the injection unit B, the drooling prevention mechanism C, and the like. Reference numeral 24 denotes an input unit, and switches LS1 and LS2 for limiting the forward / backward movement of the air cylinder 16 for forward / backward movement of the drooling prevention mechanism C.
Switches LS3 and LS4 for rotation limit of rotary air actuator 18, origin, switches E4 for completion of mold clamping of mold clamping unit A, switches E5 and E6 for forward limit and retreat limit of injection unit B (injection nozzle) 9 A signal from a switch E7 for retreating the ejector, a switch SW for manual / automatic switching, and a contact t1 of a timer T1 for holding a rotation limit position to be described later is input and transmitted to the control arithmetic means. Reference numeral 25 denotes an output unit, which is based on a signal input from the input unit 24 via the control calculation means 23, and which is used to advance and retreat the solenoids SOL1 and SOL for the forward / backward movement of the forward / backward moving air cylinder 16 of the drooling prevention mechanism C.
2. The rotation limit of the rotary air actuator 18, the solenoids SOL3 and SOL4 for the rotation operation to the origin, the solenoid SOL5 for the mold clamping operation of the mold clamping unit A, the solenoid S for the forward and backward movement of the injection unit B (injection nozzle 9).
A signal is output to OL6, SOL7, a solenoid SOL8 for retreating the ejector, a timer T1 for setting a time for keeping the rotation limit position of the rotary air actuator 18, and the like to operate them.

Next, the operation of the apparatus configured as described above will be described with reference to FIG. Normally, the injection molding machine 1 needs to supply the resin material into the heating cylinder 10 and measure the molten resin before starting the automatic operation. In this case, the measurement is performed at the retracted position of the injection unit B. When the metering operation is performed without the draining prevention mechanism C, since the opening of the injection nozzle 9 is open, the back pressure is not applied and the resin is not uniformly melted. The resin comes out from the tip of the injection nozzle 9. Such a problem occurs. Therefore,
The drooling prevention mechanism C is operated by a manual operation, and the metering operation is performed with the closing member 20 closing the opening at the tip of the injection nozzle 9. As a result, the resin can be supplied by applying a back pressure, and the melting of the resin becomes uniform, and the effect of eliminating the resin leakage from the tip of the injection nozzle 9 at the time of measurement can be obtained. Before starting the automatic operation, the closing member 20 is once moved to the standby position.

When the automatic operation of the injection molding machine 1 is started by switching the switch SW to the automatic side, the solenoid SOL5 for mold clamping operation is excited and the mold clamping unit A
Is activated, and the movable platen 6 is advanced by the driving device via the toggle mechanism 7 so that the mold K is clamped (step S).
1). When the switch E4 detects the completion of the mold clamping (step S2), the forward operating solenoid SOL1 of the forward / backward moving air cylinder 16 of the drooling prevention mechanism C is excited, and the operating rod 15 is moved forward. The closing member 20 moves forward from the standby position together with the actuator 18 (step S3). When the forward limit switch LS1 detects that the closing member 20 has reached the forward limit position (step S4), the rotary operation solenoid SOL3 to the rotation limit is excited and the rotary air actuator 18 rotates to close the closing member. 20 rotates from its retracted position to the rotation limit position where it contacts the tip of the injection nozzle 9 (step S5), whereby the opening at the tip of the injection nozzle 9 is closed.

The rotation limit switch LS3 detects that the closing member 20 has turned to the rotation limit position (step S).
6), the forward operation solenoid SOL6 is excited, and the injection unit B (the injection nozzle 9) advances (step S).
7) At the same time, the rotation limit position holding timer T1 starts counting time (step S8). When the injection unit B moves forward and reaches the position immediately before the injection nozzle 9 comes into contact with the sprue bush of the mold K, and the timer T1 for maintaining the rotation limit position finishes measuring the set time (step S9), the rotation limit is stopped. The contact t1 of the position holding timer T1 is turned on, the solenoid SOL4 for rotating operation to the home position is excited, and the rotary air actuator 18 reversely rotates toward the home position, whereby the closing member 20 reversely turns to the retreat position (step). S10) The opening of the injection nozzle 9 is opened. While the tip of the injection nozzle 9 is in contact with the closing member 20, the temperature of the tip of the closing member 20 decreases due to heat radiation to the material 20 a having a high thermal conductivity or the heat radiation mechanism, and the resin in the tip of the injection nozzle 9 also decreases. Since the temperature is lowered and the fluidity is lowered, even if the opening at the tip of the injection nozzle 9 is opened as described above, the molten resin does not leak from the opening. The switch LS4 for the origin detects the reverse turning to the retracted position (Step S).
11), the solenoid SOL2 for backward movement of the air cylinder 16 for forward and backward movement is excited, and the operating rod 15 retreats.
This causes the closing member 20 to move backward from the forward limit position together with the rotary air actuator 18 (step S12).

When the closing member 20 retreats to the standby position, it is detected by the retraction limit switch LS2 and stopped (step S13). During this time, when the injection unit B continues to advance and reaches the advance limit position, the injection nozzle 9 contacts the sprue bush of the mold K. At this time, a switch E5 for limiting forward movement of the injection unit B (injection nozzle) 9
Operates (Step S14), and the operating mechanism section 12 of the injection unit B operates to inject the molten resin in the heating cylinder 10 from the injection nozzle 9 into the mold K (Step S15). After the injection is completed, the resin material is supplied into the heating cylinder 10 to measure the molten resin. When the weighing is completed, a nozzle completion operation starts. During this time, when the molded product in the mold is solidified, a mold opening operation is started, and when the mold is completely opened, the ejector operates to eject the molded product, but when the ejection of the molded product is completed, the ejector retracts. When the solenoid SOL8 is excited and the ejector retreats (step S16) and reaches the retreat limit position, the ejector retreat limit switch E
7 (step S17).

One cycle in the operation of the injection molding machine 1 is completed as described above. In the case of nozzle touch molding in which the injection nozzle is kept in contact with the mold and molding is continued,
The above-described one cycle is performed only for the first shot at the start of the molding operation, and the well-known molding cycle without the operation of the drooling prevention mechanism C is performed from the second shot. However, in the case of the backward molding of each shot nozzle, after the injection is completed, the weighing is completed, and then the injection unit B returns to the retracted position, which is detected by the retracted position switch E6, and the mold clamping is performed. When the ejecting operation of the ejector is completed in the unit A, the next shot is started and the above-described one cycle is executed again. In this way, the above-described cycle with the operation of the drooling prevention mechanism C is repeated at every shot. A molding operation is performed.

In this case, when the injection nozzle moves to the retreat position, the molten resin in the mold K and the injection nozzle 9 adheres to the nozzle tip in a state of stringing and remains on the nozzle tip, or the molten resin in the injection nozzle 9 Even if the resin comes out of the nozzle tip due to the residual pressure of the resin and adheres to the nozzle, when the closing member 20 of the drooling prevention mechanism C comes into contact with the injection nozzle 9 in the next cycle, the closing is stopped. Tip (cutter) of member 20
In this case, the injection nozzle 9 can be easily cut and removed, so that the nozzle of the injection nozzle 9 can be reliably touched to the mold K without forming a gap between the two. The injection molding machine 1 can use any of a thermoplastic resin and a thermosetting resin as a resin material.
In the case of molding using a thermosetting resin, even if the molten resin containing glass fiber adheres and hardens to the tip of the injection nozzle 9, it is easily cut with the cutter at the tip of the closing member 20. Can be removed. Further, since the nozzle opening is closed by the closing member 20, the resin can be prevented from flowing out from the nozzle opening due to the measured resin pressure.

In the above embodiment, the pneumatic actuator is used for the forward / reverse air cylinder 16 and the rotary air actuator 18 of the drooling prevention mechanism C, but a hydraulic actuator is used instead. Alternatively, instead of the air cylinder 16 for forward / reverse travel, an actuator that moves a working rod linearly through rotation of a hydraulic motor or an electric motor via a screw mechanism may be employed. Further, since the rotary air actuator 18 does not linearly move the closing member 20, there may be an advantage that the device can be downsized and the installation space can be reduced, but instead, a linearly movable actuator is adopted. Alternatively, the closing member 20 may be reciprocated between the retracted position and the tip of the injection nozzle 9.

Although the drooling prevention mechanism C is provided to be attached to the operation mechanism section 12 of the injection unit B, the base 13, the gantry 8 and other operation mechanism sections 12 may be used instead.
And may be provided in a portion independent of. In this case, an interlocking mechanism for moving the drooling prevention mechanism C together with the injection nozzle 9 is required. Further, in a section from the retreat position of the injection unit B to the advance position immediately before the injection nozzle 9 of the heating cylinder 10 comes into contact with the mold K, a time is measured at the same time when the injection unit B starts to advance from the retreat position. Since the configuration is determined by the set time of the timer T1 to be started, it is preferable that the time until the molten resin in the tip portion of the injection nozzle 9 lowers the fluidity by the closing member 20 can be accurately determined. By providing a limit switch for detecting that the injection unit B has moved to the immediately preceding forward position on the base 13 or the like. In addition, in the injection molding machine 1, the mold clamping unit A has a vertical mold clamping system, but a general horizontal mold clamping system may be used. The injection unit B is arranged horizontally, but the injection unit B is arranged vertically. Anti-drooling mechanism C
May also be arranged vertically.

[0028]

As described above, according to the first aspect of the present invention, the section from the retracted position of the injection unit to the advanced position immediately before the injection nozzle of the heating cylinder contacts the mold, The closing member of the ring prevention mechanism is configured to move from its standby position to a position in contact with the tip of the injection nozzle to close the opening of the injection nozzle. Therefore, until the injection nozzle of the injection unit comes into contact with the mold clamped by the mold clamping unit and the nozzle touch operation is performed, the molten resin measured in the heating cylinder is discharged from the tip of the injection nozzle. Since there is no resin dripping, the sprue bush of the mold abutted by the nozzle touch operation and the tip of the injection nozzle are in close contact with each other without any gap, and the molten resin leaks from the tip of the injection nozzle to the outside during injection. Can be prevented. Further, when the closing member moves from the standby position to a position where the closing member comes into contact with the tip of the injection nozzle to close the opening of the injection nozzle, the resin attached to the tip of the injection nozzle by stringing or resin dripping may occur. If so, they can be easily removed. Since the closing member retreats to the standby position immediately before the tip of the injection nozzle comes into contact with the mold, the closing member does not hinder the nozzle touch operation.

According to the second aspect of the present invention, in the section from the retracted position of the injection unit to the advanced position immediately before the injection nozzle of the heating cylinder comes into contact with the mold, the injection unit advances from the retracted position. Since the timer is set at the same time as the start, the timer sets the timing at which no resin dripping from the injection nozzle occurs even when the closing member is retracted from the position for closing the opening of the injection nozzle to the standby position. can do.

According to the third aspect of the present invention, the drooling preventing mechanism moves the closing member between the forward position corresponding to the distal end side of the injection nozzle and the standby position separated rearward from this position. A first actuator for reciprocating in a direction parallel to the axis, a retracting position in which the closing member is closed at an advancing position at a position orthogonal to the axis of the injection nozzle and closing the opening of the injection nozzle; And a second actuator for reciprocating the closing member between the position for closing the opening of the injection nozzle and the standby position separated from the tip of the injection nozzle. It can be performed smoothly and reliably by one operation.

According to the fourth and fifth aspects of the present invention, the anti-druling mechanism connects the second actuator to the operating shaft of the first actuator, and the second actuator closes the operating shaft of the first actuator. The base ends of the members are connected,
Since the distal end of the closing member is configured as a rotary actuator that pivots between a position where the opening of the injection nozzle is closed and a retracted position that is separated to the side of the injection nozzle, the closing member is configured such that the opening of the injection nozzle is closed. The structure of the device for reciprocating between the closed position and the retracted position and between the retracted position and the standby position has a simple structure, requires a small installation space, and can be easily implemented.

According to the sixth aspect of the present invention, since a material having high thermal conductivity is provided at a portion of the tip of the closing member that closes the opening of the injection nozzle, the closing member closes the opening of the injection nozzle. When this occurs, the tip of the injection nozzle is radiated satisfactorily, and the fluidity of the molten resin in the tip of the injection nozzle decreases. Therefore, when the closing member releases the opening of the injection nozzle just before the tip of the injection nozzle comes into contact with the mold, it is possible to prevent the molten resin from leaking from the opening. According to the invention of claim 7, even if the injection nozzle is large in thickness, outside diameter, etc., and the heat capacity is large, the tip end of the injection nozzle is more appropriately cooled by the heat radiation mechanism provided in the closing member. The tip can be efficiently cooled.

According to the seventh aspect of the present invention, a cutter having a blade surface on the front side leading to contact with the tip of the injection nozzle is provided at a portion of the tip of the closing member for closing the opening of the injection nozzle. With this arrangement, the resin adhering to the tip of the injection nozzle can be easily cut and removed even if it is a thermosetting resin containing glass fiber.

According to the eighth aspect of the present invention, since the injection unit injects the thermosetting resin into the mold, the thermosetting resin is likely to be thermoset and fixed to the tip of the injection nozzle. It can be easily applied to resin.

[Brief description of the drawings]

FIG. 1 is a side view of an injection molding machine provided with a resin drooling prevention device of the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a plan view showing an embodiment of a resin drooling prevention device of the present invention.

FIG. 4 is a side view of the same.

FIG. 5 is a front view of the same.

FIG. 6 is a block diagram showing a control device of an injection molding machine provided with the resin drooling prevention device of the present invention.

FIG. 7 is a flowchart showing the operation of an injection molding machine provided with the resin drooling prevention device of the present invention.

[Explanation of symbols]

A Mold Clamping Unit B Injection Unit C Drooling Prevention Mechanism K Die 9 Injection Nozzle 10 Heating Cylinder 12 Operating Mechanism 16 Air Cylinder for Forward / Reverse 18 Rotary Air Actuator 20 Closing Member 20c Cutter 22

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Tomomitsu Fujita 1300, Okayama, Niigata City, Niigata Prefecture Inside Niigata Ironworks Niigata Seiki Factory (72) Inventor Eisaku Suzuki 1300, Okayama, Niigata City, Niigata Prefecture Niigata Iron Works Niigata Co., Ltd. Inside the Precision Equipment Factory (72) Inventor Hideo Ito 2-5-8 Higashishinagawa, Shinagawa-ku, Tokyo Sumitomo Bakelite Co., Ltd. F-term (reference) 4F206 JA07 JL02 JM01 JQ55

Claims (9)

[Claims] An injection unit provided so as to be able to move forward and backward with respect to the mold clamped by the mold clamping unit, to advance from a retreat position to contact an injection nozzle of a heating cylinder with the mold; An injection molding machine for injecting the molten resin in the heating cylinder from the injection nozzle into a mold, wherein the injection resin of the heating unit is moved from a retracted position to an advanced position immediately before the injection nozzle of the heating cylinder comes into contact with the mold. section,
An apparatus for preventing resin drooling at the tip of a nozzle in an injection molding machine, wherein a closing member moved from a standby position to a position in contact with the tip of the injection nozzle is provided with a drooling prevention mechanism for closing an opening of the injection nozzle. . 2. A section from the retreat position of the injection unit to a forward position immediately before the injection nozzle of the heating cylinder comes into contact with the mold, is a timer that starts timing simultaneously with the start of forward movement of the injection unit from the retreat position. 2. The apparatus for preventing resin drooling at the tip of a nozzle in an injection molding machine according to claim 1, wherein the setting time is determined by the set time. 3. The drooling prevention mechanism moves the closing member in a direction parallel to the axis of the injection nozzle between a forward position corresponding to the tip side of the injection nozzle and a standby position separated from this position rearward. A first actuator for reciprocating movement, and a reciprocating movement between a position for closing the opening of the injection nozzle orthogonal to the axis of the injection nozzle at the forward position of the closing member at its forward position and a retracted position spaced apart to the side of the injection nozzle. The apparatus according to claim 1 or 2, further comprising a second actuator for causing a resin drooling at the tip of the nozzle in the injection molding machine. 4. The resin drooling prevention at the tip of a nozzle in an injection molding machine according to claim 3, wherein the second actuator is connected to the operating shaft of the first actuator. apparatus. 5. The second actuator, wherein a base end of the closing member is connected to an operation shaft thereof, and a distal end of the closing member is separated from a position for closing an opening of the injection nozzle and to a side of the injection nozzle. The apparatus for preventing resin drooling at the tip of a nozzle in an injection molding machine according to claim 3 or 4, wherein the rotary actuator is a rotary actuator that pivots between the retracted position. 6. A material having high thermal conductivity is provided at a portion of the tip of the closing member that closes an opening of an injection nozzle.
An apparatus for preventing resin drooling at the tip of a nozzle in the injection molding machine according to any one of the above. 7. The apparatus for preventing resin drooling at the tip of a nozzle in an injection molding machine according to claim 1, wherein the closing member is provided with a heat radiating mechanism. 8. A cutter having a blade surface on a front side leading to contact with a tip portion of the injection nozzle at a portion for closing an opening of the injection nozzle at a tip portion of the closing member. An apparatus for preventing resin drooling at the tip of a nozzle in the injection molding machine according to any one of claims 1 to 7. 9. The injection unit according to claim 1, wherein the injection unit is configured to inject a thermosetting resin into the mold as a molten resin in the heating cylinder. For preventing resin drooling at the tip of a nozzle in an injection molding machine.