JP7617641B2 - Mold unit and injection molding machine - Google Patents

Description

The present invention relates to a mold unit that places an undercut and uses a core for molding, and an injection molding machine that uses the same.

Patent document 1 describes a simplified molding die, according to which the simplified injection molding die is composed of a fixed die, a movable die, and a core insert, and is configured to mold a molded product by filling the closed mold space formed by the fixed die, the movable die, and the core insert with molten resin, and then cooling and solidifying it.

JP 2001-205679 A

However, with the simplified molding die described above, when the molded product is ejected, the core is removed from the die together with the molded product by the ejector pin and then manually returned to the die.

To ensure that the core has been returned, it is possible to compare a reference image with the real-time image, but there is a risk that the accuracy of the judgment will be reduced due to differences in the amount of light that hits the image due to the time difference between the reference image and the real-time image.

It is also possible to use a touch sensor, but this would reduce the accuracy of the judgment due to thermal expansion of the mold and the core, and would require wiring, which could complicate the configuration.

For these reasons, if molding operations were performed without the core being fully returned to the mold, there was a risk that it would interfere with the mold when it was closed, causing damage to the mold.

The present invention provides a mold unit and injection molding machine with a simple configuration that can reliably return a core to the mold before performing molding operations without damaging the mold.

The invention of claim 1 provides a mold unit for use in an injection molding machine, which molds a molded product by injecting molten resin into a product molding section formed by a fixed mold, a movable mold that moves toward and away from the fixed mold, and a core placed in the fixed mold and/or the movable mold,
The die unit includes the fixed die, the movable die, and the placement core,
The fixed-side mold and/or the movable-side mold in which the placement core is disposed include:
a recessed portion is provided so as to open toward the product molding portion, and a first air passage through which air can flow and a second air passage through which air can flow are provided at a position different from the first air passage so as to communicate with the recessed portion,
the placing core is formed to be movable within the recess and is capable of simultaneously closing the first air passage and the second air passage,
the second air passage is connected in this order to a detection means for detecting an air pressure in the second air passage and a negative pressure means for putting the second air passage into a negative pressure state;
In an assembled state, the detection means is connected to a control means for controlling the operation of the injection molding machine,
When molding of the molded product is completed and the movable mold is separated from the fixed mold, the placed core is positioned in the recess to close the first air passage and the second air passage, and when the detection means detects that a predetermined air pressure is reached, a signal to enable the movable mold to operate is output to the control means.

With this, the first air passage and the second air passage are closed by the placed core, and the detection means detects that the air pressure is at a specified level, making it possible to create a mold unit with a simple configuration that can reliably return the placed core to the mold before performing molding work and without damaging the mold.

In addition, an ejector capable of sending the core to the product molding section can be placed in the first air passage.

This allows the first air passage to also function as a passage for placing the ejector, resulting in a simple configuration.

According to a third aspect of the present invention, there is provided an injection molding machine for molding a molded product by injecting molten resin into a product molding section formed by a fixed mold, a movable mold that moves toward and away from the fixed mold, and a core placed in the fixed mold and/or the movable mold,
a recessed portion opening toward the product molding portion is provided in the fixed mold and/or the movable mold in which the placement core is disposed, and a first air passage through which air can flow and a second air passage through which air can flow are provided at a position different from the first air passage so as to communicate with the recessed portion,
the placing core is formed to be movable within the recess and is capable of simultaneously closing the first air passage and the second air passage,
the second air passage is connected in this order to a detection means for detecting an air pressure in the second air passage and a negative pressure means for putting the second air passage into a negative pressure state;
a control means for controlling the operation of the injection molding machine and connected to the detection means;
When the molding of the molded product is completed and the movable mold is separated from the fixed mold, the control means positions the placing core within the recess to close the first air passage and the second air passage, and when the detection means detects that a predetermined air pressure is reached, makes the movable mold operable.

This allows the injection molding machine to achieve the effects of the mold unit described in claim 1.

In addition, an ejector capable of sending the core to the product molding section is provided in the first air passage.

This allows the injection molding machine to achieve the effects of the mold unit described in claim 2.

The negative pressure means and the detection means are disposed outside the fixed die and/or the movable die in which the core is placed.

This allows the negative pressure means and detection means to be removed from the fixed mold and/or the movable mold for maintenance, making maintenance management easier.

A filter is also provided between the second air passage and the detection means.

This allows the filter to prevent malfunctions of the negative pressure means and detection means caused by dirt.

1 is a schematic side view of an injection molding machine according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a main part of the embodiment. 2 is an explanatory diagram showing an operating state of a main part of the injection molding machine of the embodiment. FIG. FIG. 4 is an explanatory diagram showing a continued operating state of FIG. 3; FIG. 5 is an explanatory diagram showing a continued operation state of FIG. 4 . FIG. 6 is an explanatory diagram showing a continued operating state of FIG. 5 . FIG. 7 is an explanatory diagram showing a continued operating state of FIG. 6; FIG. 8 is an explanatory diagram showing a continued operating state of FIG. 7; FIG. 13 is an explanatory diagram showing a modified example in which a placement core is placed in a fixed mold.

One embodiment of the injection molding machine of the present invention will be described with reference to the drawings. In the following description, the arrows in each drawing indicate F as front, B as back, R as right, L as left, U as up, and D as down.

As shown in FIG. 1, the injection molding machine 10 has an injection device 20, a mold clamping device 30, and a mold 50.

In the injection device 20, a screw 22 is disposed inside a cylindrical heating barrel 21, and the screw 22 is rotated by a hydraulic motor 23. A heater 24 for melting synthetic resin W is disposed on the outer circumferential surface of the heating barrel 21. A hopper 25 for storing synthetic resin W and supplying it into the heating barrel 21 is disposed at the front end of the heating barrel 21.

In the injection device 20, the synthetic resin W is heated by the heater 24 and turned into a molten state, molten resin W1, which is transported by the screw 22 and can be extruded from the nozzle 26 disposed at the rear end of the heating barrel 21.

The mold clamping device 30 has a fixed platen 31 fixed on the bed 11, an end housing 32 arranged behind the fixed platen 31, a plurality of divers 33 arranged between the fixed platen 31 and the end housing 32, a movable platen 34 arranged between the fixed platen 31 and the end housing 32 and formed so that the divers 33 can be inserted, a toggle mechanism 36 arranged between the end housing 32 and the movable platen 34 and having a crosshead 35, a servo motor 37 as a drive device for driving the toggle mechanism 36, and a belt 39 connecting the servo motor 37 and the toggle mechanism 36 via a pulley 38.

An ejector 40 is provided on the movable platen 34, and an ejector rod 40a can be inserted through an insertion hole 34a formed in the movable platen 34 along the front-rear direction. An ejector pin 42 is attached to the front end of the ejector rod 40a via a plate-shaped plate 41, making it possible to push the completed molded product F forward.

The mold clamping device 30 has a movable platen 34 that can move in the front-to-rear direction by being driven by a servo motor 37.

As shown in Figures 3 to 8, the mold 50 has a fixed mold 51, a movable mold 52, and a core holder 60.

The fixed die 51 is formed in a rectangular parallelepiped shape and is attached to the fixed platen 31. A receiving port 31a formed in a shape corresponding to the nozzle 26 is disposed at a position of the fixed platen 31 facing the nozzle 26. The fixed die 51 is formed with a sprue flow passage 51c that runs from the front end surface 51a to the rear end surface 51b and communicates with the receiving port 31a.

The movable mold 52 is formed in a rectangular parallelepiped shape and is attached to the movable platen 34.

The movable mold 52 is composed of a front block 53 and a rear block 54.

The front block 53 is provided with a bottomed hole portion 53c formed as a bottomed hole extending from the front end face 53a to the rear end face 53b of the front block 53, an ejector passage forming hole portion 53d formed as a bottomed hole extending from the rear end face 53b to the front end face 53a of the front block 53 and narrower than the bottomed hole portion 53c, and a communication hole portion 53e formed narrower than the bottomed hole portion 53c and wider than the ejector passage forming hole portion 53d, connecting the bottomed hole portion 53c and the ejector passage forming hole portion 53d.

The front block 53 is provided with a second air passage 53f that extends rearward from the bottomed hole 53c in parallel with the ejector passage forming hole 53d and then downward. The negative pressure measuring unit 70, which will be described later, is connected to the second air passage 53f.

The rear block 54 is provided with a plate placement section 54c formed as a through hole extending from the front end surface 54a to the rear end surface 54b of the rear block 54.

The core 60 is formed so that it can move in the forward and backward directions within the communication hole 53e. The core 60 is provided with a molding recess 60c that is formed as a recess extending from the outer periphery toward the axis.

In this embodiment, the space surrounded by the rear end surface 51b of the fixed mold 51, the bottomed hole portion 53c, the front end surface 60a and molding recess 60c of the placement core 60, and the portion of the communicating hole portion 53e facing the molding recess 60c is the product molding portion 55. In other words, the communicating hole portion 53e forms part of the product molding portion 55, and the portion that does not form the product molding portion 55 functions as a recess in the scope of the claims.

The ejector passage forming hole 53d and the plate arrangement portion 54c form the first air passage 52a in the claims, and the plate 41 and ejector pin 42 that form the ejector 40 are arranged in the first air passage 52a. There are gaps between the ejector rod 40a and the insertion hole 34a, and between the ejector pin 42 and the ejector passage forming hole 53d, allowing air to flow.

In this embodiment, the mold unit is made up of a fixed mold 51, a movable mold 52, a core holder 60, and a negative pressure measurement unit 70.

As shown in FIG. 2, the negative pressure measurement unit 70 includes a vacuum generator 71 as a negative pressure means for creating a negative pressure state in the second air passage 53f, a pressure switch 72 as a detection means for detecting the air pressure in the second air passage 53f, and a filter 73, and is connected to the second air passage 53f.

The second air passage 53f is connected, via a filter 73, to a detection means for detecting the air pressure in the second air passage 53f, and to a negative pressure means for creating a negative pressure state in the second air passage 53f. The vacuum generator 71 is also connected to an air compressor 75, and generates negative pressure by the force of the air supplied from the air compressor 75. The arrows in FIG. 2 indicate the flow of air.

In this embodiment, the mold unit is made up of a fixed mold 51, a movable mold 52, a core holder 60, and a negative pressure measurement unit 70.

In the injection molding machine 10, the injection device 20, the mold clamping device 30, the negative pressure measurement unit 70, etc. are connected to a control means 80 equipped with a communication interface, a control circuit, and a calculation processing circuit.

To explain the main parts of the present invention, as shown in FIG. 2, the pressure switch 72 of the negative pressure measurement unit 70 and the mold 50 (movable mold 52) are connected to the control means 80. The vacuum generator 71 and the air compressor 75 operate independently of the control of the control means 80.

The vacuum generator 71, pressure switch 72 and air compressor 75 are set to operate continuously during molding operations.

When the pressure switch 72 detects an air pressure within a predetermined range close to a vacuum, it outputs a signal to the control means 80 to enable the movable mold 52 to operate.

The following describes how to use the injection molding machine 10.

The injection device 20 of the injection molding machine 10 moves toward the mold clamping device 30 and presses the rear end of the nozzle 26 against the receiving port 31a.

At this time, as shown in FIG. 3, the mold clamping device 30 is in a state in which the fixed mold 51 and the movable mold 52 are close to each other. In addition, with the core 60 blocking the first air passage 52a and the second air passage 53f, the pressure switch 72 detects that the pressure is in a predetermined range close to a vacuum, so the movable mold 52 is in an operable state.

When a predetermined injection volume of molten resin W1 is injected from the nozzle 26, the molten resin W1 passes through the sprue flow path 51c and is injected into the product molding section 55, as shown in FIG. 3.

When the specified injection volume of molten resin W1 has been injected, the injection device 20 moves forward to prepare for the next injection operation.

When molding of the molded product F is completed, as shown in FIG. 4, the movable mold 52 is moved away from the fixed mold 51 by driving the servo motor 37, and then, as shown in FIG. 5, the ejector 40 is driven to move the ejector pin 42 forward, which pushes the rear end surface 60b of the core 60, and the molded product F integrated with the core 60 is ejected.

After the worker separates the core 60 from the molded product F as shown in Figure 6, he or she returns the core 60 to the recessed communicating hole portion 53e as shown in Figure 7.

When in the state shown in Figures 5 to 7, the vacuum generator 71 and pressure switch 72 are in an activated state, but there is a gap between the ejector pin 42 and the ejector passage forming hole 53d, and the core 60 does not block the first air passage 52a and the second air passage 53f, allowing air to flow in. Therefore, the pressure switch 72 does not detect that it is in a predetermined range close to a vacuum, and the movable mold 52 does not operate.

As shown in FIG. 8, when the core 60 blocks the first air passage 52a and the second air passage 53f, the pressure switch 72 detects the change in air pressure caused by the vacuum generator 71, in other words, that the pressure is in a predetermined range close to a vacuum, and outputs a signal to the control means 80 to enable the movable mold 52 to operate. This enables the movable mold 52 to operate.

When the above invention is considered as a mold unit, it is a mold unit used in an injection molding machine, which molds a molded product F by injecting molten resin W1 into a product molding section 55 formed by a fixed mold 51, a movable mold 52 that moves toward and away from the fixed mold 51, and a placement core 60 placed in the movable mold 52,
The die unit includes a fixed die 51, a movable die 52, and a placement core 60.
The movable die 52 in which the placement core 60 is disposed has the following:
A recess (communication hole portion 53e) that opens toward the product molding portion 55 is provided, and a first air passage 52a (ejector passage forming hole portion 53d and plate arrangement portion 54c) through which air can flow and a second air passage 53f through which air can flow are provided at a position different from the first air passage 52a so as to communicate with the recess,
The stationary core 60 is formed to be movable within the recess (the communication hole portion 53e) and is capable of simultaneously closing the first air passage 52a and the second air passage 53f,
The second air passage 53f is connected in this order to a detection means (pressure switch 72) that detects the air pressure in the second air passage 53f, and a negative pressure means (vacuum generator 71) that makes the second air passage 53f in a negative pressure state.
In the assembled state, the detection means is connected to a control means 80 that controls the operation of the injection molding machine 10.
When the molding of the molded product F is completed and the movable side mold 52 is separated from the fixed side mold 51, the placed core 60 is positioned in the recess to close the first air passage 52a and the second air passage 53f, and when the detection means detects that the air pressure is at a predetermined level, a signal to enable the movable side mold 52 to operate is output to the control means 80.

With this, the first air passage 52a and the second air passage 53f are closed by the stationary core 60, and the detection means detects that the air pressure is at a predetermined level, so that the stationary core 60 can be returned reliably to the movable mold 52 with a simple configuration, and molding work can be performed, resulting in a mold unit that does not damage the mold 50.

In addition, an ejector 40 capable of sending the placement core 60 to the product molding section 55 can be placed in the first air passage 52a.

This allows the first air passage 52a to also function as a passage for placing the ejector 40, resulting in a simple configuration.

In addition, when the present invention is viewed as an injection molding machine, it is an injection molding machine that molds a molded product F by injecting molten resin W1 into a product molding section 55 formed by a fixed mold 51, a movable mold 52 that moves toward and away from the fixed mold 51, and a placement core 60 placed in the movable mold 52,
A recess (communication hole portion 53e) opening to face the product molding portion 55 is provided in the movable mold 52 in which the stationary core 60 is arranged, and a first air passage 52a through which air can flow and a second air passage 53f through which air can flow are provided at a position different from the first air passage 52a so as to communicate with the recess,
The stationary core 60 is formed to be movable within the recess (the communication hole portion 53e) and is capable of simultaneously closing the first air passage 52a and the second air passage 53f,
The second air passage 53f is connected in this order to a detection means (pressure switch 72) that detects the air pressure in the second air passage 53f, and a negative pressure means (vacuum generator 71) that makes the second air passage 53f in a negative pressure state.
A control means 80 is provided which controls the operation of the injection molding machine 10 and is connected to the detection means;
When the molding of the molded product F is completed and the movable side mold 52 is separated from the fixed side mold 51, the control means 80 positions the placement core 60 in the recess to close the first air passage 52a and the second air passage 53f, and when the detection means detects that the air pressure is at a predetermined level, makes the movable side mold 52 operable.

This allows the injection molding machine to achieve the effects of the above-mentioned mold unit.

In addition, an ejector 40 capable of sending the placement core 60 to the product molding section 55 is disposed in the first air passage 52a.

This allows the injection molding machine to achieve the effects of the above-mentioned mold unit.

In addition, a negative pressure means (vacuum generator 71) and a detection means (pressure switch 72) are provided on the outside of the movable mold 52, where the placement core 60 is placed.

This allows the negative pressure means and detection means to be removed from the movable mold 52 for maintenance, making maintenance management easier.

A filter 73 is also provided between the second air passage 53f and the detection means (pressure switch 72).

As a result, the filter 73 can prevent malfunctions of the negative pressure means and detection means due to dirt.

The present invention is not limited to the above configuration. In other words, various design changes are possible without departing from the gist of the present invention. The same numbers are used for configurations similar to those in the first embodiment, and descriptions thereof will be omitted in whole or in part.

For example, a modified example in which a core is placed on the fixed die will be described with reference to Figure 9.

The fixed mold 151 is provided with a bottomed hole portion 151c formed as a bottomed hole extending from the rear end surface 151b of the fixed mold 151 to the front end surface 151a, and a communication hole portion 151e formed as a bottomed hole having a smaller width than the bottomed hole portion 151c and extending from the bottom of the bottomed hole portion 151c to the front end surface 151a of the fixed mold 151.

The fixed mold 151 is provided with a first air passage 151d that extends forward from the bottomed hole portion 151c and then downward.

In addition, the fixed mold 151 is provided with a second air passage 151f that extends forward from the bottomed hole portion 151c and then upward. The negative pressure measurement unit 70 is connected to the second air passage 151f.

This simple configuration allows the mold unit and injection molding machine to be constructed in such a way that the core 60 can be reliably returned to the fixed mold 151 before molding, without damaging the mold 50.

The clamping device 30 is of the toggle type, but a direct pressure type clamping device can also be used.

In addition, the injection device 20 is not limited to the above configuration and any existing injection device can be used as long as it can inject the molten resin W1 into the product molding section 55.

The shape of the product molding portion 55 can also be changed as appropriate.

It is also possible to reverse the concaves and convexes of the fixed mold 51 and the movable mold 52.

The core 60 can also be placed in the fixed mold 51 and the movable mold 52.

10 Injection molding machine 40 Ejector 51 Fixed side mold 52 Movable side mold 52a First air passage 53d Ejector passage forming hole portion 53e Communication hole portion 53f Second air passage 54c Plate arrangement portion 55 Product molding portion 60 Placed core 71 Vacuum generator 72 Pressure switch 80 Control means 151 Fixed side mold 151d First air passage 151e Communication hole portion 151f Second air passage F Molded product W1 Molten resin

Claims (6)

A mold unit used in an injection molding machine, which molds a molded product by injecting molten resin into a product molding section formed by a fixed mold, a movable mold that moves toward and away from the fixed mold, and a core placed in the fixed mold and/or the movable mold,
The die unit includes the fixed die, the movable die, and the placement core,
The fixed-side mold and/or the movable-side mold in which the placement core is disposed include:
a recessed portion is provided so as to open toward the product molding portion, and a first air passage through which air can flow and a second air passage through which air can flow are provided at a position different from the first air passage so as to communicate with the recessed portion,
the placing core is formed to be movable within the recess and is capable of simultaneously closing the first air passage and the second air passage,
the second air passage is connected in this order to a detection means for detecting an air pressure in the second air passage and a negative pressure means for putting the second air passage into a negative pressure state;
In an assembled state, the detection means is connected to a control means for controlling the operation of the injection molding machine,
When molding of the molded product is completed and the movable mold is separated from the fixed mold, the placement core is positioned in the recess to close the first air passage and the second air passage, and when the detection means detects a predetermined air pressure, a signal to enable the movable mold to operate is output to the control means. The mold unit according to claim 1, characterized in that an ejector capable of sending the placement core toward the product molding section can be disposed in the first air passage. An injection molding machine that molds a molded product by injecting molten resin into a product molding section formed by a fixed-side mold, a movable-side mold that moves toward and away from the fixed-side mold, and a core placed in the fixed-side mold and/or the movable-side mold,
a recessed portion opening to face the product molding portion is provided in the fixed mold and/or the movable mold in which the placement core is disposed, and a first air passage through which air can flow and a second air passage through which air can flow are provided at a position different from the first air passage so as to communicate with the recessed portion,
the placing core is formed to be movable within the recess and is capable of simultaneously closing the first air passage and the second air passage,
the second air passage is connected in this order to a detection means for detecting an air pressure in the second air passage and a negative pressure means for putting the second air passage into a negative pressure state;
a control means for controlling the operation of the injection molding machine and connected to the detection means;
the control means, when molding of the molded product is completed and the movable-side mold is separated from the fixed-side mold, the placement core is positioned in the recess to close the first air passage and the second air passage, and when the detection means detects a predetermined air pressure, makes the movable-side mold operable. An injection molding machine according to claim 3, characterized in that an ejector capable of sending the core to the product molding section is provided in the first air passage. An injection molding machine according to claim 3 or 4, characterized in that the negative pressure means and the detection means are arranged outside the fixed mold and/or the movable mold in which the core is placed. 5. The injection molding machine according to claim 3, further comprising a filter disposed between said second air passage and said detection means.

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