JP2022133239A - Apparatus, mold, injection molding machine, manufacturing unit, manufacturing method of resin molded product, valve unit - Google Patents

Abstract

To improve a durability of a backflow prevention valve in order to ensure stable operation of an injection molding machine over a long term.SOLUTION: An apparatus includes: a first flow passage member defining a first section of a flow passage; a second flow passage member defining a second section of the flow passage; a valve unit capable of deterring backflow in the flow passage; and a fastening member capable of fastening the first flow passage member and the second flow passage member. When the first flow passage member and the second flow passage member are fastened by the fastening member, the valve unit is held between the first flow passage member and the second flow passage member, and the first section and the second section are connected through the valve unit. When the first flow passage member and the second flow passage member are released from fastening by the fastening member, the valve unit can be detached from the first flow passage member and the second flow passage member.SELECTED DRAWING: Figure 1

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten resin flow path capable of preventing reverse flow in a device that handles molten resin, such as an injection molding machine.

2. Description of the Related Art Conventionally, an injection molding method is known as a method for manufacturing resin products. In the injection molding method, molten resin is injected into the cavity space inside the mold using a screw, plunger, etc., cooled and solidified in the mold, and after solidification, the mold is opened and the molded product is taken out. Resin molded products are continuously mass-produced by repeating a series of operations from injecting molten resin to taking out molded products. For example, pre-plunger type (hereinafter referred to as pre-plastic type) and in-line screw type molding machines are known as apparatuses for performing injection molding.

For example, a pre-plastic injection molding machine has a plasticizing mechanism with a screw and a plunger for injecting a molten resin material. A valve is provided. The molten resin extruded from the screw into the channel passes through the open valve and is supplied to the plunger side. Thereafter, by closing the valve and advancing the plunger, the molten resin is injected into the mold cavity. At this time, by closing the valve, the resin is prevented from flowing back to the screw side, and an appropriate injection pressure is ensured.
As a valve capable of opening and closing the flow path of the molten resin, there is a system in which power is supplied to the opening and closing mechanism from the outside to operate, but a system with a simpler structure is also being studied.
Patent Literature 1 and Patent Literature 2 describe a backflow prevention valve that opens and closes by moving a valve body using a pressure difference between molten resins before and after the valve.

JP-A-2004-255588 JP-A-2004-330672

The backflow prevention valve, which opens and closes by utilizing the pressure difference between the molten resin before and after the valve, has the advantage of being simpler in structure than the system in which power is supplied to the opening and closing mechanism from the outside. Therefore, it can be installed not only between the screw and the plunger of the preplasticating injection molding machine, but also at various positions in the flow path of the molten resin of the injection molding machine, depending on the purpose.

In the backflow prevention valves described in Patent Document 1 and Patent Document 2, the pressure difference of the molten resin in the forward flow direction causes the valve body to move in the valve and abut against the stopper during the opening operation. It has a structure in which the opening of the flow path is secured even if the contact is made. During the closing operation, the pressure difference in the molten resin in the reverse flow direction causes the valve body to move inside the valve and press against the valve seat. It has a structure.

In such a conventional backflow prevention valve, the valve body and the valve seat, or the valve body and the stopper are repeatedly pressed and separated during operation of the injection molding machine, and these portions wear out. In particular, during the closing operation, the pressure difference between the molten resin before and after the valve directly acts on the contact portion between the valve body and the valve seat, so the contact portion is easily worn. If the valve seat is damaged, it will not be possible to completely close the flow path of the molten resin, and the backflow prevention function will deteriorate.
Therefore, in order to ensure that the injection molding machine can operate stably for a long period of time, there has been a demand for improved durability of the backflow prevention valve.

In addition, although not examined in Patent Document 1 and Patent Document 2, when the backflow prevention valve is worn, the worn backflow prevention valve is removed from the injection molding machine, and a new or repaired backflow prevention valve is installed in the injection molding machine. Need to re-install. Assuming such replacement, there is a need for a method that facilitates attachment and detachment of the backflow prevention valve and that allows the backflow prevention valve to be attached to the flow path with a high degree of adhesion so that the molten resin does not leak from the attachment portion.

A first aspect of the present invention comprises: a first flow channel member defining a first section of a flow channel; a second flow channel member defining a second section of the flow channel; a valve unit that can be restrained; and a fastening member that can fasten the first flow path member and the second flow path member, wherein the first flow path member and the second flow path member are fastened by the fastening member. In the fastened state, the valve unit is sandwiched between the first flow path member and the second flow path member, the first section and the second section are connected via the valve unit, and the first section is connected to the second section. The valve unit is detachable from the first flow path member and the second flow path member in a state where the first flow path member and the second flow path member are released from fastening by the fastening member. It is a device that

In a second aspect of the present invention, a first flow path member defining a first section of a flow path, a second flow path member defining a second section of the flow path, and a valve unit capable of suppressing backflow, wherein the first section and the second section are connected via the valve unit, and the valve unit includes a displaceable valve body and a valve body that contacts the valve body. a first valve seat portion capable of closing the flow path when in contact with the first valve seat portion, the first valve seat portion being in contact with the first flow path member and made of a material forming the first flow path member; The device is characterized in that it is made of a material with a high hardness.

ADVANTAGE OF THE INVENTION According to this invention, a backflow prevention valve with high durability is provided, and a manufacturing apparatus can be operated stably for a long period of time. When replacing the backflow prevention valve, the backflow prevention valve can be easily attached and detached, and the backflow prevention valve can be attached to the flow path member with a high degree of adhesion so that the molten resin does not leak from the attachment portion.

FIG. 4 is a schematic cross-sectional view showing a state in which the backflow prevention valve 5 according to Embodiment 1 is attached to the flow path of the molten resin. FIG. 4 is a schematic cross-sectional view showing a state before the backflow prevention valve 5 according to Embodiment 1 is incorporated into the molten resin flow path. (a) A schematic cross-sectional view of the backflow prevention valve 5 according to the first embodiment. (b) A schematic perspective view of a fragment on the side including the outflow port 38, which is obtained by cutting the backflow prevention valve 5 along the plane A-A' shown in FIG. 3(a), viewed from the inflow side. (a) A schematic cross-sectional view showing a state in which molten resin flows forward. (b) A schematic perspective view showing a state in which molten resin flows forward. (a) A schematic cross-sectional view of the backflow prevention valve 5 according to the first embodiment. (b) A schematic perspective view of a fragment on the side including the inflow port 37, which is obtained by cutting the backflow prevention valve 5 along the B-B' plane shown in FIG. 5(a), from the outflow side. (a) A schematic cross-sectional view showing a state in which molten resin is about to flow in the reverse direction. (b) A schematic perspective view showing a state in which the molten resin is about to flow in the reverse direction. FIG. 4 is a schematic cross-sectional view showing the force applied to each part when the backflow prevention valve 5 is closed. FIG. 8 is a schematic cross-sectional view showing a state in which a pre-plastic injection molding machine 80 according to Embodiment 2 performs a weighing process; FIG. 8 is a schematic cross-sectional view showing a state in which a pre-plastic injection molding machine 80 according to Embodiment 2 performs an injection process and a pressure holding process; FIG. 11 is a schematic cross-sectional view showing a state in which the family molding apparatus 100 according to Embodiment 3 performs an injection process; FIG. 11 is a schematic cross-sectional view showing a state in which the family molding apparatus 100 according to Embodiment 3 performs a pressure holding process; FIG. 11 is a schematic cross-sectional view showing a state in which the family forming apparatus 100 according to Embodiment 3 performs a weighing process; (a) A schematic cross-sectional view showing a state in which a backflow prevention valve 50 according to Embodiment 4 is attached to a molten resin flow path. (b) A schematic cross-sectional view showing a state in which a backflow prevention valve 51 according to Embodiment 5 is attached to a molten resin flow path. FIG. 11 is a schematic cross-sectional view showing a state in which a backflow prevention valve 52 according to Embodiment 6 is attached to a molten resin flow path. FIG. 11 is a schematic cross-sectional view showing a state in which a backflow prevention valve 53 according to Embodiment 7 is attached to a molten resin flow path. FIG. 12 is a schematic cross-sectional view of a pre-plastic injection molding machine according to Embodiment 8; FIG. 11 is a schematic cross-sectional view of a family forming apparatus according to Embodiment 9;

DESCRIPTION OF THE PREFERRED EMBODIMENTS A molten resin flow path, an injection molding machine, and the like having a backflow prevention valve according to embodiments of the present invention will be described with reference to the drawings.
In addition, in the drawings referred to in the following description of the embodiments, unless otherwise specified, the elements shown with the same reference numbers have the same functions.

[Embodiment 1]
A backflow preventive valve according to Embodiment 1 and a method of mounting the backflow preventive valve to a molten resin flow path will be described.
FIG. 1 is a cross-sectional view schematically showing a state in which a backflow prevention valve 5 according to Embodiment 1 is attached to a molten resin flow path. FIG. 2 is a cross-sectional view schematically showing a state before the backflow prevention valve 5 is incorporated into the molten resin flow path. In FIG. 1, the forward flow direction and the reverse flow direction of the molten resin are indicated by arrows, and the inflow side and outflow side of the flow channel are displayed with the forward flow direction as a reference.
The backflow prevention valve 5 as a valve unit includes a valve body 10 , a first valve seat portion 9 , a second valve seat portion 11 and a housing 8 . The function of each part of the backflow prevention valve 5 will be described later.

The backflow prevention valve 5 is sandwiched between the first flow path member 1 and the second flow path member 2 from the left and right direction in the figure, and the first flow path member 1 and the second flow path member 2 are fastened at the flange portion. It is fastened by the bolt 6 which is a member. A first flow path section 1C is defined in the first flow path member 1 as a part of the flow path for the molten resin, and a second flow path section 1C is defined in the second flow path member 2 as a part of the flow path for the molten resin. Two channel sections 2C are defined. The first channel section 1C and the second channel section 2C are connected via a backflow prevention valve 5 to form a series of channels 3 through which the molten resin flows.

As shown in FIG. 2, the first flow path member 1 is provided with a recess having a depth of L1 with respect to the flange surface 1F when viewed in the flow path axial direction. Further, the second channel member 2 is provided with a recess having a depth L2 with respect to the flange surface 2F when viewed in the channel axial direction. The end surface (bottom surface) of the recess of the first flow path member 1 is 1T, and the end surface (bottom surface) of the recess of the second flow path member 2 is 2T.
In the backflow prevention valve 5, the distance between 5L and 5R is set to LB when the end surface on the first flow path member 1 side is 5R and the end surface on the second flow path member 2 side is 5L. That is, the backflow prevention valve 5 has a length LB when viewed in the direction of the channel axis.

In this embodiment, the dimensions of each part are defined so as to satisfy the following formula (1).
L1+L2<LB (1) formula

In the assembled state shown in FIG. 1, the end surface 1T of the first flow path member 1 and the end surface 5R of the backflow prevention valve 5 are in contact with each other, and the end surface 2T of the second flow path member 2 and the end surface 5L of the backflow prevention valve 5 are in contact with each other. abuts. On the other hand, since the dimensional relationship is defined by the formula (1), the first flow path member 1 and the second flow path member 2 can be strongly fastened with the bolts 6 . Since the first flow path member 1, the second flow path member 2, and the housing 8 of the backflow prevention valve 5 can be considered to be substantially rigid bodies, the distance TM as interference is substantially equal to LB-(L1+L2). Specifically, the distance TM as the tightening margin is preferably set within a range of 2 μm or more and 100 μm or less, and particularly preferably set within a range of 7 μm or more and 50 μm or less. This is to enable fastening with a strong fastening force and to prevent the bolt from buckling when an external force is applied between the first channel member 1 and the second channel member 2 .

According to this embodiment, since the distance TM as interference is ensured by the dimensional relationship defined in the formula (1), the first flow path member 1 and the second flow path member sandwiching the backflow prevention valve 5 2 can be fastened with sufficient force using bolts 6 . Therefore, the end face 1T and the end face 5R, and the end face 2T and the end face 5L can be brought into close contact with sufficient pressure, and the interface between the backflow prevention valve 5 and the first flow path member 1 and the backflow prevention valve 5 and the second flow path member 1 can be brought into close contact. It is possible to prevent the molten resin from leaking from the interface of the channel member 2 .

According to this embodiment, sufficient sealing performance can be achieved without joining the flow path member and the backflow prevention valve by brazing or the like, so the backflow prevention valve can be easily mounted. Also, when replacing the backflow prevention valve, the backflow prevention valve can be easily removed from the flow path member by removing the fastening member (bolt) as shown in FIG. The load can be greatly reduced.

The depth L1 of the recess of the first flow path member 1 and the depth L2 of the recess of the second flow path member 2 can be of any size as long as the formula (1) is satisfied. For example, only one of the first channel member 1 and the second channel member 2 may be provided with a concave portion, and the other may have a depth of 0 (that is, a flat surface).

Next, the backflow prevention valve 5 as a valve unit will be described in detail. As shown in FIG. 1 , the check valve 5 includes a valve body 10 , a first valve seat portion 9 , a second valve seat portion 11 and a housing 8 .

FIG. 3(a) is a schematic cross-sectional view of the check valve 5, but the illustration of the valve body 10 is omitted for convenience of explanation. Inside the check valve 5, there is formed a flow path for molten resin connecting the inflow port 37 and the outflow port 38, and the spherical valve element 10 shown in FIG. possible). Since the diameter of the spherical valve body 10 is larger than that of both the inflow port 37 and the outflow port 38, the valve body 10 does not deviate from the check valve 5 and can be located anywhere in the valve chamber 7. ing.

A concave portion is provided on the inflow side of the housing 8, and a first valve seat portion 9 is fitted in the concave portion. The bottom surface of the recess and the tip surface of the first valve seat portion 9 are in contact with each other at the boundary portion 14 . In this embodiment, the cross-sectional area of the molten resin in the backflow prevention valve 5 is maximized at the boundary portion 14 where the bottom surface of the concave portion of the housing 8 and the tip surface of the first valve seat portion 9 abut. there is This is to make it difficult for the high-pressure molten resin to leak from the boundary. However, depending on the pressure of the molten resin in the valve chamber 7, the boundary portion 14 may be separated from the position where the channel cross-sectional area is maximized.

First, it will be explained that the backflow prevention valve 5 is opened when the molten resin tends to flow in the forward direction.
FIG. 3(b) is a schematic perspective view of a fragment of the side including the outflow port 38 of the housing 8 cut along the AA' plane shown in FIG. 3(a) and viewed from the inflow side. is. A second valve seat portion 11 is provided on the outflow side of the flow path to hold the valve element 10 in the flow path without blocking the flow path when the molten resin flows forward. The second valve seat portion 11 is composed of four protrusions (stoppers) distributed in the outer peripheral direction of the flow path. pressed against the department.

In order to explain this state, FIG. 4(a) is a schematic cross-sectional view of the backflow prevention valve 5, and FIG. 4(b) is a schematic perspective view that is virtually cut in the same manner as FIG. 3(b). indicates The spherical valve body 10 receives a force Fv due to the flow pressure in the forward flow direction and abuts on the slopes of the projections of the second valve seat portion 11. Between the projections, there is a gap 36 through which the molten resin can pass. is ensured. Therefore, the molten resin can flow out from the outflow port 38, and the anti-reflux valve 5 maintains an open state with respect to the flow in the forward direction.

The ridgeline of the protrusion of the second valve seat portion 11 is inclined from the inflow side to the outflow side so as to approach the center of the flow path axis, and along the flow path axis from the inflow side. It has a shape that does not have an undercut part that would be a shadow when the projection is viewed from above. As a result, the molten resin flowing in the forward direction does not stagnate in the vicinity of the protrusions, thereby suppressing deterioration of the resin due to stagnation.

Next, it will be explained that the backflow preventive valve 5 is closed when the molten resin tries to flow in the reverse direction.
FIG. 5(a) is a schematic cross-sectional view of the check valve 5, but the illustration of the valve body 10 is omitted for convenience of explanation. FIG. 5(b) is a schematic view of the backflow prevention valve 5 cut along the BB' plane shown in FIG. It is a perspective view. The BB' plane is a plane passing through the boundary portion 14 where the bottom surface of the concave portion of the housing 8 and the tip end surface of the first valve seat portion 9 abut. there is The first valve seat portion 9 is a cylindrical member, and the inner surface of the cylinder has a conical portion 13 whose diameter decreases from the outflow side to the inflow side. When the molten resin tries to flow in the reverse direction, the spherical valve body 10 is pressed against the conical surface-shaped portion 13 on the inner surface of the first valve seat portion 9 by the fluid pressure.

In order to explain this state, FIG. 6(a) is a schematic cross-sectional view of the backflow prevention valve 5, and FIG. 6(b) is a schematic perspective view cut virtually in the same manner as FIG. 5(b). indicates The spherical valve element 10 _receives force FM due to the flow pressure in the reverse flow direction and abuts against the conical surface-shaped portion 13 of the first valve seat portion 9 . There are no gaps through which the molten resin can flow. Therefore, it becomes impossible for the molten resin to flow back and flow out from the inlet 37, and against the flow in the reverse direction, the backflow prevention valve 5 is closed to block the flow path of the molten resin.

The open state and closed state of the backflow prevention valve 5 have been described above, and the configuration of each part of the backflow prevention valve 5 will be described in more detail. When the backflow prevention valve 5 is mounted in an injection molding machine or the like and the opening and closing operations of the flow path are repeated, the valve body 10 is repeatedly pressed against the protrusion of the second valve seat portion 11 and the first valve seat portion 9 . When the molten resin flows in the forward direction and the valve is open, the gap 36 through which the molten resin can pass is ensured, so the pressure with which the valve body 10 is pressed against the protrusion of the second valve seat portion 11 is not so high. Not big. On the other hand, when the molten resin is about to flow in the reverse flow direction and the valve is in a closed state, the flow path is closed. receive power.

In this embodiment, in order to improve the durability of the first valve seat portion 9, the first valve seat portion 9 is formed using a material having higher hardness than the first flow path member 1, and the first valve seat portion 9 are mounted on the housing 8. The second valve seat portion 11, which has a relatively small pressing force against the valve body but has a complicatedly shaped protrusion, is formed integrally with the housing 8 using a material with excellent workability. On the other hand, the first valve seat portion 9, which requires higher durability, is formed using a material with higher hardness than the material used for the first flow path member 1, and is mounted on the housing 8. As shown in FIG.

The cylindrical first valve seat portion 9 has a cylindrical outer peripheral surface and is fitted into a recess provided in the housing 8 . As a fitting method, shrink fitting, which has a high adhesion strength, is preferable from the viewpoint of suppressing resin leakage. In some cases, other fitting methods such as light press fitting may be used. The inflow-side end face 15 of the first valve seat portion 9 is flush with the inflow-side end face of the housing 8 or slightly protrudes toward the inflow side. When the first flow path member 1 and the second flow path member 2 are fastened with the bolts 6, the first valve seat portion 9 and the first flow path member 1 are firmly adhered to prevent leakage of the molten resin. is.

Next, with reference to FIG. 7, the force applied to each part when the backflow prevention valve 5 is closed will be described in more detail. FIG. 7 is a cross-sectional view schematically showing a state in which pressure is applied in the backflow direction and the backflow prevention valve 5 is closed.

Since the first valve seat portion 9 is pushed in the reverse flow direction by the valve body 10 and a high pressure is applied to the inside of the valve chamber 7, a gap should be formed at the boundary portion 14 between the housing 8 and the first valve seat portion 9. A force _FV is generated as follows. This force may create a minute gap at the edge of the boundary portion 14 and allow molten resin to enter. However, since the first valve seat portion 9 is tightly fitted to the housing 8 by shrink fitting or the like, there is no leakage from between the cylindrical outer surface of the first valve seat portion 9 and the concave inner surface of the housing 8 . . That is, the molten resin does not enter the contact surface between the backflow prevention valve 5 and the first flow path member 1, and the molten resin does not leak to the outside.

In the closed state, the valve body 10 is pressed against the first valve seat portion 9, so that the entire valve unit of the check valve 5 is pressed toward the _inflow side with a force FM. This force acts in a direction to separate the outflow-side end surface 16 of the backflow prevention valve 5 from the end surface of the second channel member 2 . However, as already described with reference to FIG. The member 2 is firmly fastened with bolts 6 . This prevents the molten resin from leaking out from the contact portion between the backflow prevention valve 5 and the second channel member 2 .

The open state and the closed state have been described above, and supplementary information will be given on materials constituting each part.
For the first flow path member 1 and the second flow path member 2, materials having a hardness (Rockwell hardness) of HRC 20 or more and less than 50 ( For example, SUS steel) is suitable.

For the housing 8 of the backflow prevention valve, for example, alloy tool steel (SKD11, die steel) with hardness (Rockwell hardness) of HRC62, high speed steel (SKH51, high speed steel) with hardness of HRC63, or hardness of HRC50. ~55 SUS-based materials are suitable. This is due to the balance between the ease of processing when forming the concave portion for receiving the first valve seat portion 9 and the convex portion of the second valve seat portion 11 and the durability during use.

A material having a hardness (Rockwell hardness) of HRC 50 or more and less than 80 is suitable for the first valve seat portion 9 . In order to increase the durability during use, a material is selected which has a hardness higher than that of the first channel member 1 and which is not so hard as to make processing excessively difficult. Specifically, alloy tool steel (SKD11, die steel) with a hardness (Rockwell hardness) of HRC62, high speed steel (SKH51, high speed steel) with a hardness of HRC63, and SUS materials with a hardness of HRC50 to 55 is suitable.
From the viewpoint of durability, the valve body 10 is preferably made of cemented carbide (cemented carbide) having a hardness (Rockwell hardness) of HRC 78, for example.

Moreover, when the molten resin actually flows, each part of the device becomes hot. At this time, the first flow path member 1, the second flow path member 2, the housing 8, and the first valve seat portion 9 are all connected to a wire so that a gap is not generated due to a difference in thermal expansion and the sealing performance of the flow path is not deteriorated. A material having an expansion coefficient of 9×10 ⁻⁶ /K or more and 13×10 ⁻⁶ /K or less is used. In particular, in order to ensure the tight contact between the first valve seat portion 9 and the contact portion of the first flow path member 1, the coefficient of linear expansion of the material forming the first valve seat portion 9 should be within the above range. It is preferable to make the coefficient of linear expansion larger than that of the material forming one channel member 1 .

Examples of preferable combinations of materials forming each part are as follows.
The first flow path member 1 and the second flow path member 2 are made of SUS having a hardness of HRC 29 or more and 33 or less and a linear expansion coefficient of 10.1×10 ⁻⁶ /K or more and 11.5×10 ⁻⁶ /K or less. It is formed of a steel material (for example, HPM77 manufactured by Hitachi Metals, Ltd.). The housing 8 of the backflow prevention valve is made of SUS material with a hardness of HRC50-55. The first valve seat portion 9 is made of high speed steel (SKH51, high speed steel) having a hardness of HRC63 and a coefficient of linear expansion of 11.9×10 ⁻⁶ /K. The valve body 10 is made of cemented carbide (cemented carbide) with a hardness of HRC78.

According to the present embodiment described above, since the first valve seat portion 9 with which the valve body 10 contacts with a strong force when preventing backflow is formed of a material having a hardness higher than that of the first channel member, The durability of the backflow prevention valve 5 is improved, and it can operate stably over a long period of time.

In addition, the first flow path member 1 and the second flow path member 2 are firmly fastened with bolts 6 in a state in which the backflow prevention valve 5 is sandwiched between the first flow path member 1 and the second flow path member 2. The first flow path member 1 and the second flow path member 2 are separated from each other via the interference of the bolts 6 . Due to such a structure that can exert a strong fastening force, the first flow path member 1 and the backflow prevention valve 5, and the second flow path member 2 and the backflow prevention valve 5 are in close contact (contact) with a strong force. It is possible to prevent the molten resin from leaking through the gap.

According to this embodiment, sufficient sealing performance can be achieved without joining the flow path member and the backflow prevention valve by brazing or the like, so the backflow prevention valve can be easily mounted. In addition, when replacing the backflow prevention valve, it can be easily removed from the flow path member by removing the fastening member (bolt) and releasing it, greatly reducing the load required for maintenance of the injection molding machine. can be reduced to

[Embodiment 2]
As Embodiment 2, the configuration and operation of the pre-plastic injection molding machine equipped with the backflow prevention valve shown in Embodiment 1 will be described. 8 and 9 show schematic cross-sectional views of a pre-plastic injection molding machine equipped with a backflow prevention valve. FIG. 8 shows a state in which the pre-plastic injection molding machine 80 performs a weighing process, which will be described later, and FIG. 9 shows a state in which the pre-plastic injection molding machine 80 performs an injection process and a holding pressure process, which will be described later. there is In the description of the backflow prevention valve 5 shown in the drawing, the portions common to the description of the first embodiment will be omitted or simplified.

(Structure of pre-plastic molding machine)
A pre-plastic injection molding machine 80 includes a molten resin supply section 81 , an injection section 82 , and a mold cavity 20 . A molten resin supply unit 81 supplies molten resin, and an injection unit 82 injects molten resin. The molten resin supply unit 81 includes a heater (not shown) for melting resin pellets, which are molding materials, and a screw 17 (for example, φ35 mm) for pushing out the molten resin toward the injection unit 82 . The injection section 82 includes a sleeve 18 that stores the molten resin supplied from the molten resin supply section 81 , a plunger 21 (for example, φ20 mm) that can move back and forth within the sleeve 18 , a switching valve 24 , and a nozzle 19 . The tip of the nozzle 19 is connected to the gate of the mold cavity 20 as an injection port for molten resin. The switching valve 24 can open and close the hot runner channel connecting the sleeve 18 and the nozzle 19 . A heater (not shown) for maintaining the molten resin at an appropriate temperature (for example, 230° C.) is attached to the molten resin supply section 81 and the injection section 82 .

The molten resin supply section 81 and the injection section 82 are connected by the connection section 22 . The connection part 22 connects the first flow path member 1 defining the first section (for example, φ8 mm) of the flow path, the backflow prevention valve 5 shown in Embodiment 1, and the second section (for example, φ8 mm) of the flow path. It has a second channel member 2 that defines it. Furthermore, a pressure sensor 23 for measuring the resin pressure in the flow path is installed in the first flow path member 1 . The first channel member 1 and the second channel member 2 are made of SUS material, and are provided with a heater (not shown) for maintaining the molten resin in the channel at an appropriate temperature (for example, 230°C). It is

For the dimensions described with reference to FIGS. 1 and 2, L1+L2=20 mm and LB=20.03 mm. The flange portions of the first flow path member 1 and the second flow path member 2 are fastened with 12 bolts 6 (for example, M12) with a tightening margin of TM=0.03 mm.

The housing 8 of the backflow prevention valve 5 (for example, cylindrical with an outer diameter of φ30 mm) is made of SUS material, and the passage diameter at the position where the passage cross-sectional area is maximized is φ14 mm. The first valve seat portion 9 is made of high-speed steel having higher hardness than the SUS material of the first flow path member 1, and the diameter of the outer peripheral surface is set to 18 mm. Also, the first valve seat portion 9 is fitted to the housing 8 by shrink fitting. A valve chamber defined by the housing 8 and the first valve seat portion 9 has a spherical valve body 10 (for example, 10 mm in diameter) made of cemented carbide (a cemented carbide) inserted therein.

(Molding process)
Next, a molding process using the pre-plastic injection molding machine 80 will be described.
First, as shown in FIG. 8, the switching valve 24 of the injection section 82 is closed, the plunger 21 is moved upward in the drawing by a predetermined distance, and a predetermined amount of molten resin is measured and introduced into the sleeve 18. carry out the process. The raw material melted in the molten resin supply section 81 is extruded from the molten resin supply section 81 by the screw 17 rotating at 100 rpm. At this time, as described with reference to FIGS. 4(a) and 4(b), since the flow is in the forward direction in the check valve 5, the check valve 5 is opened. The molten resin that has passed through the anti-backflow valve 5 is measured by the distance traveled by the plunger 21 and stored in the sleeve 18 . At this time, a back pressure of 10 MPa was applied to the plunger 21 . The metering process is complete when the plunger 21 retracts to the metering setpoint = 100mm.

Next, with reference to FIG. 9, the injection process and the subsequent holding pressure process will be described. When the amount of molten resin required for molding the resin molded product is stored in the sleeve 18 in the weighing process described above, the preplasticating injection molding machine 80 performs an injection process in which the molten resin is injected into the mold cavity 20. to implement.

In the injection process, as shown in FIG. 9, the switching valve 24 is opened to allow communication between the sleeve 18 and the nozzle 19, and the plunger 21 is advanced in the direction of the nozzle 19 at 100 mm/s to fill the mold cavity 20 with molten resin. . At this time, a resin pressure of 200 MPa is applied to the valve chamber 7 of the backflow prevention valve 5, which is the same as described with reference to FIGS. 6(a) and 6(b). 5 acts in the countercurrent direction. Therefore, the backflow prevention valve 5 is closed, and the backflow of the molten resin to the molten resin supply section 81 is prevented.

When the filling of the mold cavity 20 with the molten resin is completed, the resin in the gate portion is solidified ( A pressure holding process is performed to pressurize until the gate is sealed. During the dwell step, the plunger 21 operates in pressure control mode, which controls pressure rather than position. In the holding pressure process, a pressure of 50 MPa was applied for 3 seconds. Also in the pressure holding process, the pressure on the outflow side > the pressure on the inflow side for the backflow prevention valve 5, and a differential pressure acts in the reverse flow direction. Therefore, the backflow prevention valve 5 is kept closed, and the backflow of the molten resin to the molten resin supply section 81 is prevented.

When the molten resin filled in the mold cavity 20 is solidified, the mold is opened and the resin molded product is taken out, while the weighing process for the next injection molding is started, and the check valve 5 is opened again. becomes.

Through the injection process and the pressure holding process, a high pressure of 200 MPa at maximum is applied to the backflow prevention valve 5 in a closed state. However, even when injection molding was repeatedly performed many times, resin leakage did not occur at the connecting portion 22 in the pre-plastic injection molding machine 80 of the present embodiment in which the backflow prevention valve was excellent in durability.

In this embodiment, the pressure sensor 23 can be used to check whether the backflow prevention valve 5 is normally opening and closing. If the backflow prevention valve 5 is properly closed in the injection process and the pressure holding process, the high pressure state on the outflow side (plunger side) will not propagate to the first section of the flow path. If the pressure sensor 23 detects an abnormal pressure rise, it can be assumed that the backflow prevention valve 5 is malfunctioning. In this case, in the pre-plastic injection molding machine 80 of the present embodiment, the backflow prevention valve can be easily removed from the flow path member by removing the fastening member (bolt), and the backflow prevention valve can be easily replaced. be. In this way, the load required for maintenance of the injection molding machine can be suppressed.

[Embodiment 3]
As Embodiment 3, the configuration and operation of the family molding machine equipped with the backflow prevention valve shown in Embodiment 1 will be described. A family molding machine is an injection molding machine, which is equipped with a manufacturing unit such as a mold for taking multiple pieces of different shapes. The injection molding machine used in the family molding apparatus of this embodiment is of the in-line screw type, and can plasticize, inject, and measure the molding material by rotating, advancing, and retracting the screw as described later.

10 to 12 show schematic cross-sectional views of the family forming apparatus 100 equipped with the backflow prevention valve 5. FIG. 10 shows a state in which the family molding apparatus 100 performs an injection process described later, FIG. 11 shows a state in which the family molding apparatus 100 performs a holding pressure process described later, and FIG. 12 illustrates a family molding apparatus. 100 indicates a state in which a weighing process, which will be described later, is performed. In the description of the backflow prevention valve 5 shown in the drawing, the portions common to the description of the first embodiment will be omitted or simplified.

(Configuration of Family Molding Equipment)
The family molding apparatus 100 includes a molten resin supply section 30 and a manufacturing unit, and the manufacturing unit includes a first cavity 25, a second cavity 26, a hot runner 27, a plunger 28, and a pressure control device 29 that drives the plunger 28. . The first cavity 25 and the second cavity 26 are cavities for molding resin molded products having different shapes, and the inner volume of the first cavity 25 is larger than that of the second cavity 26 . Molten resin is supplied to the first cavity 25 and the second cavity 26 from a molten resin supply section 30 via a manifold-shaped hot runner 27 . A first gate valve 31 that can be opened and closed is provided at the tip of the injection nozzle on the first cavity 25 side, and a second gate valve 32 that can be opened and closed is provided at the tip of the injection nozzle on the second cavity 26 side. there is

In the hot runner 27, the flow path branched from the molten resin supply section 30 side to the first cavity 25 side is provided with the backflow prevention valve 5 shown in Embodiment 1 so that the molten resin supply section 30 faces the inflow side. is installed. That is, the backflow prevention valve 5 is mounted so that the direction from the molten resin supply portion 30 to the first cavity 25 is the forward flow direction. The anti-backflow valve 5 is sandwiched between the first flow path member 1 and the second flow path member 2 that constitute the hot runner 27, and as shown in FIG. 2 are fastened with bolts. Furthermore, a pressure sensor 23 for measuring the resin pressure in the flow path is installed in the first flow path member 1 .
The first channel member 1 and the second channel member 2 are made of SUS material, and are provided with a heater (not shown) for maintaining the molten resin in the channel at an appropriate temperature (for example, 230°C). It is

The dimensions described with reference to FIGS. 1 and 2 were L1+L2=35 mm and LB=35.03 mm. The flange portions of the first flow path member 1 and the second flow path member 2 are fastened with 12 bolts 6 (for example, M12) with a tightening margin of TM=0.03 mm.

The housing 8 of the backflow prevention valve 5 (for example, a cylindrical outer diameter of φ30 mm) is made of SUS material, and the flow passage diameter at the position where the flow passage cross-sectional area is maximized is set to φ14 mm. The first valve seat portion 9 is made of high-speed steel having higher hardness than the SUS material of the first flow path member 1, and the diameter of the outer peripheral surface is set to 18 mm. Also, the first valve seat portion 9 was fitted to the housing 8 by shrink fitting. A valve chamber defined by the housing 8 and the first valve seat portion 9 has a spherical valve body 10 (for example, 10 mm in diameter) made of cemented carbide (a cemented carbide) inserted therein.

(Molding process)
Next, a molding process using the family molding machine 100 will be described.
In this embodiment, in the injection process, the molten resin is filled into the first cavity 25 and the second cavity 26 from the molten resin supply section 30 almost simultaneously. In the subsequent holding pressure step, suitable different holding pressures are applied to the deformed first cavity 25 and the second cavity 26 . That is, the pressure is applied from the plunger 28 driven by the pressure control device 29 to the first cavity 25 having a large internal volume and a large appropriate pressure. On the other hand, a holding pressure is applied from the screw 33 of the molten resin supply section 30 to the second cavity 26 having a small internal volume and a small appropriate holding pressure. In the holding pressure process, since the backflow prevention valve 5 is closed, it is possible to apply proper holding pressure to each of the first cavity 25 and the second cavity 26 without causing the molten resin to flow back.

First, the injection process will be described with reference to the schematic cross-sectional view of FIG.
In the injection process, first, with the second gate valve 32 connected to the second cavity closed, the first gate valve 31 connected to the first cavity 25 is opened, and the screw 33 of the molten resin supply section 30 is advanced at 50 mm/s. let me A predetermined amount of the molten resin stored in the molten resin supply section 30 is pushed out into the flow path of the hot runner 27 by the advancing screw 33, but since the second gate valve 32 is closed, the first cavity 25 flowing towards Since this flow is in the forward direction of the check valve 5 as described with reference to FIGS. 4(a) and 4(b), the check valve 5 is opened and the molten resin 25 is filled. By investigating in advance the relationship between the advance amount of the screw 33 and the amount of molten resin supplied to the hot runner 27, the amount of resin filled in the first cavity 25 can be grasped. For example, when the internal volume of the first cavity is 60 cm ³ and the internal volume of the second cavity is 30 cm ³ , the second gate valve 32 is opened when the unfilled volume of the first cavity reaches 30 cm ³ . Control. After that, molten resin is supplied to both cavities in parallel, so filling can be completed almost simultaneously.

Next, the pressure holding process will be described with reference to the schematic cross-sectional view of FIG. 11 .
In the holding pressure process, a holding pressure is applied to the flow path of the hot runner 27 using the plunger 28 of φ14 under the control of the pressure control device 29 . Specifically, a holding pressure of 80 MPa was applied to the hot runner channel for 3 seconds. On the other hand, using the screw 33 of the molten resin supply section 30, pressure is applied to the flow path of the hot runner 27. As shown in FIG. Specifically, a holding pressure of 50 MPa was applied to the flow path of the hot runner 27 for 3 seconds.

At this time, for the backflow prevention valve 5, the outflow side pressure > the inflow side pressure. acts on Therefore, the backflow prevention valve 5 is closed, and the backflow of the molten resin to the molten resin supply section 81 is prevented. A holding pressure of 80 MPa applied from the plunger 28 is applied to the first cavity, and a holding pressure of 50 MPa applied by the screw 33 is applied to the second cavity 26 . Thus, in this embodiment, by closing the backflow prevention valve 5, it is possible to apply different holding pressures suitable for each cavity at the same time.
After the pressure holding process is completed, the first gate valve 31 and the second gate valve 32 are closed, and the weighing process is started in preparation for the next injection molding.

Next, the weighing process will be described with reference to the schematic cross-sectional view of FIG.
In the weighing process, the positions of the screw 33 and the plunger 28 of the molten resin supply section 30 are reset to the starting positions of the injection process, and a predetermined amount of molten resin required in the next injection process is supplied to the molten resin supply section 30. store. At this time, the screw 33 is rotated at 100 rpm to apply a back pressure of 10 MPa, and the plunger 28 is retracted at 50 mm/s. The pressure on the outflow side of the check valve 5 is forcibly released and becomes 0 MPa, while the pressure on the inflow side becomes 10 MPa. Therefore, in the same manner as described with reference to FIGS. 4(a) and 4(b), a differential pressure in the forward direction is generated in the backflow prevention valve 5, and the backflow prevention valve 5 is opened, hindering the weighing process. can be done without When the resin in the cavity is solidified after cooling time, the mold is opened and the resin molded products are taken out from the first cavity 25 and the second cavity 26, respectively. After completion of take-out and weighing, the process moves to the injection process again.

In this embodiment, a high pressure of 80 MPa is applied to the backflow prevention valve 5 in the valve closed state through the pressure holding process. However, even if the injection molding is repeated many times, in the family molding machine 100 of the present embodiment, the connecting portion between the backflow prevention valve 5 and the flow path forming members (the first flow path member 1 and the second flow path member 2) Resin leakage did not occur at , and appropriate holding pressure was performed.

In this embodiment, the pressure sensor 23 can be used to check whether the backflow prevention valve 5 is normally opening and closing. In the holding pressure step, if the backflow prevention valve 5 is properly closed, the high pressure state on the outflow side (plunger side) will not propagate to the first section of the flow path. If the pressure sensor 23 detects an abnormal pressure rise, it can be assumed that the backflow prevention valve 5 is malfunctioning. In that case, with the family forming apparatus 100 of the present embodiment, the backflow prevention valve can be easily removed from the flow path member by removing the fastening member (bolt), and the backflow prevention valve can be easily replaced. be. In this way, the load required for maintenance of the manufacturing unit can be reduced.

[Embodiment 4]
A backflow preventive valve 50 according to Embodiment 4 and a method of mounting the backflow preventive valve to the molten resin flow path will be described with reference to the schematic cross-sectional view of FIG. 13(a). The backflow prevention valve 50 of this embodiment differs in configuration from the backflow prevention valve 5 of the first embodiment.
The backflow prevention valve 5 of Embodiment 1 has a housing 8 made of, for example, a SUS material, and has a second valve seat portion 11 . A first valve seat portion 9 made of a material (for example, high-speed steel) harder than the first flow path member 1 (for example, SUS material) is fitted to the inflow side of the housing 8 .

In the backflow prevention valve of Embodiment 4, the housing is composed of an inflow-side housing member 34A and an outflow-side housing member 34B. The housing is divided into a housing member 34A and a housing member 34B at a position where the flow passage cross-sectional area of the valve chamber 7 is maximized. there is However, depending on the pressure of the molten resin in the valve chamber 7, the division position does not have to coincide with the position where the channel cross-sectional area is maximized. A first valve seat portion 9 (conical portion 13) is formed on the housing member 34A, and a second valve seat portion 11 (projection) is formed on the housing member 34B.

Assuming that the first flow path member 1 and the second flow path member 2 are made of SUS material, for example, the housing member 34A and the housing member 34B are made of a material (for example, high-speed steel) having higher hardness than the flow path member in this embodiment. ing. As in the first embodiment, the dimensional relationship satisfies L1+L2<LB.

According to this embodiment, the first valve seat portion 9 with which the valve body 10 contacts with a strong force when preventing backflow is made of a material having a hardness higher than that of the first channel member. Further, the second valve seat portion 11 with which the valve element 10 contacts during the forward flow is made of a material having hardness higher than that of the second flow path member. Therefore, the durability of the backflow prevention valve 50 is improved, and it can operate stably over a long period of time.

In addition, the first flow path member 1 and the second flow path member 2 are firmly fastened with bolts 6 in a state in which the backflow prevention valve 50 is sandwiched between the first flow path member 1 and the second flow path member 2. The first flow path member 1 and the second flow path member 2 are separated from each other via the interference of the bolts 6 . Due to such a structure that can exhibit a strong fastening force, the first flow path member 1 and the backflow prevention valve 50, and the second flow path member 2 and the backflow prevention valve 50 are in close contact (abutment) with a strong force. Outflow of the molten resin from the gap is suppressed.

According to this embodiment, sufficient sealing performance can be achieved without joining the flow path member and the backflow prevention valve by brazing or the like, so the backflow prevention valve can be easily mounted. Also, when replacing the backflow prevention valve, it can be easily removed from the flow path member by removing the fastening member (bolt). The required load can be greatly reduced.

[Embodiment 5]
A backflow prevention valve 51, which is a modification of the fourth embodiment, will be described with reference to the schematic cross-sectional view of FIG. 13(b). The fourth embodiment differs from the present embodiment in the shape of the contact surfaces of the housing member 34A and the housing member 34B. In the fourth embodiment, the contact surfaces of the housing member 34A and the housing member 34B are planes orthogonal to the channel axis direction, but in the present embodiment, the contact surfaces have a stepped shape.

It would be convenient if the housing member 34A, the housing member 34B, and the valve body 10 could be handled as an integral valve unit before mounting the backflow prevention valve to a manufacturing device such as an injection molding machine or a manufacturing unit, rather than separately handling them as separate parts. is. According to this embodiment, the housing member 34A and the housing member 34B can be fitted to each other due to the stepped shape, and the valve unit can be assembled. Installation work is easy.

[Embodiment 6]
A backflow prevention valve 52 that is a modification of the fourth embodiment will be described with reference to the schematic cross-sectional view of FIG. The fourth embodiment and the present embodiment have the same shape of the contact surface of the housing member 34A and the housing member 34B. Both are fastened by the bolt 35 which is.

It would be convenient if the housing member 34A, the housing member 34B, and the valve body 10 could be handled as an integral valve unit before mounting the backflow prevention valve to a manufacturing device such as an injection molding machine or a manufacturing unit, rather than separately handling them as separate parts. is. According to this embodiment, the housing member 34A and the housing member 34B can be fastened with the bolts 35, and the valve unit can be assembled. Easy to work with.

[Embodiment 7]
A backflow prevention valve 53, which is a modification of the first embodiment, will be described with reference to the schematic cross-sectional view of FIG.
A backflow prevention valve 53 of the present embodiment has a housing 8 made of, for example, SUS material, and has a second valve seat portion 11, like the backflow prevention valve 5 of the first embodiment. A first valve seat portion 9 made of a material (for example, high-speed steel) having higher hardness than the first flow path member 1 (for example, SUS material) is fitted to the inflow side of the housing 8 .

The difference from the first embodiment is that a through hole is provided in the housing 8, and the bolt 6, which is a fastening member, is inserted in a state in which the backflow prevention valve 53 is sandwiched between the first flow path member 1 and the second flow path member 2. The point is that these are fastened by penetrating the

In this embodiment as well, the first valve seat portion 9, which the valve body 10 contacts with a strong force when preventing backflow, is made of a material having a hardness higher than that of the first flow path member. The durability is improved, and it can operate stably for a long period of time.

Further, according to the present embodiment, since sufficient sealing performance can be achieved by the fastening member without joining the flow path member and the backflow prevention valve by brazing or the like, the backflow prevention valve can be easily mounted. Also, when replacing the backflow prevention valve, it can be easily removed from the flow path member by removing the fastening member (bolt). The required load can be greatly reduced.

[Embodiment 8]
A detailed configuration of the pre-plastic injection apparatus equipped with the backflow prevention valve shown in the second embodiment will be described. FIG. 16 shows a schematic cross-sectional view of a pre-plastic injection molding machine equipped with a backflow prevention valve. FIG. 16 shows a state in which the pre-plastic injection molding machine 80 performs a weighing process, which will be described later. In the description of the backflow prevention valve 5 shown in the drawing, the portions common to the description of the first embodiment will be omitted or simplified.

(Structure of pre-plastic molding machine)
A pre-plastic injection molding machine 80 includes a molten resin supply section 81 , an injection section 82 , and a mold cavity 20 . The molten resin supply unit 81 includes a heater (not shown) for melting resin pellets, which are molding materials, and a screw 17 (for example, φ35 mm) for pushing out the molten resin toward the injection unit 82 . The injection section 82 includes a sleeve 18 that stores the molten resin supplied from the molten resin supply section 81 , a plunger 21 (for example, φ20 mm) that can move back and forth within the sleeve 18 , a switching valve 24 , and a nozzle 19 . The tip of the nozzle 19 is connected to the gate of the mold cavity 20 as an injection port for molten resin. The switching valve 24 can open and close the hot runner channel connecting the sleeve 18 and the nozzle 19 . A heater (not shown) for maintaining the molten resin at an appropriate temperature (for example, 230° C.) is attached to the molten resin supply section 81 and the injection section 82 .

The connection part 22 connects the first flow path member 1 defining the first section (for example, φ8 mm) of the flow path, the backflow prevention valve 5 shown in Embodiment 1, and the second section (for example, φ8 mm) of the flow path. It has a second channel member 2 that defines it. Furthermore, a pressure sensor 23 for measuring the resin pressure in the flow path is installed in the first flow path member 1 . The first channel member 1 and the second channel member 2 are made of SUS material, and are provided with a heater (not shown) for maintaining the molten resin in the channel at an appropriate temperature (for example, 230°C). It is

The backflow prevention valve 5 is sandwiched between the connecting portions 22 . The molten resin supply part 81 is attached to the first channel member 1 by bolting. Also, the injection part 82 is attached to the second flow path member 2 by bolting. Further, the nozzle 19 is formed with a threaded portion, and is attached by being tightened to a threaded hole formed in the second channel member 2 .

When replacing the backflow prevention valve 5, separate the first flow path member 1 and the molten resin supply section 81 in the direction in which the first flow path member 1 and the molten resin supply section 81 are aligned (the vertical direction in FIG. 16). . In addition, the second flow path member 2 and the injection section 82 are separated in the direction in which the second flow path member 2 and the injection section 82 are arranged (vertical direction in FIG. 16). In this way, the molten resin supply section 81, the injection section 82, and the nozzle 19 are removed from the first channel member 1 and the second channel member 2, respectively. After that, the bolts of the connecting portion 22 are removed, and the first flow path member 1 and the second flow path member 2 are aligned in the direction in which the first flow path member 1 and the second flow path member 2 are arranged (horizontal direction in FIG. 16). separate the Thereby, the anti-backflow valve 5 can be removed from between the first channel member 1 and the second channel member 2 .
For the dimensions described with reference to FIGS. 1 and 2, L1+L2=20 mm and LB=20.03 mm. The flange portions of the first flow path member 1 and the second flow path member 2 are fastened with 12 bolts 6 (for example, M12) with a tightening margin of TM=0.03 mm.

The housing 8 of the backflow prevention valve 5 (for example, cylindrical with an outer diameter of φ30 mm) is made of SUS material, and the passage diameter at the position where the passage cross-sectional area is maximized is φ14 mm. The first valve seat portion 9 is made of high-speed steel having higher hardness than the SUS material of the first flow path member 1, and the diameter of the outer peripheral surface is set to 18 mm. Also, the first valve seat portion 9 is fitted to the housing 8 by shrink fitting. A valve chamber defined by the housing 8 and the first valve seat portion 9 has a spherical valve body 10 (for example, 10 mm in diameter) made of cemented carbide (a cemented carbide) inserted therein.

Assuming that the molten resin supply section 81 is called a first component and the injection section 82 is called a second component, this embodiment has the following characteristic configuration. The first component is detachably connected to the first flow path member 1 and the second component is detachably connected to the second flow path member 2 . The attachment/detachment direction of the first flow path member 1 and the first component member (vertical direction in FIG. 16) intersects the direction in which the first flow path member 1 and the second flow path member 2 are arranged (horizontal direction in FIG. 16). there is The attachment/detachment direction of the second flow path member 2 and the second component member (vertical direction in FIG. 16) intersects the direction in which the first flow path member 1 and the second flow path member 2 are arranged (horizontal direction in FIG. 16). there is By doing so, there are advantages such as, for example, realizing miniaturization of the device, facilitating assembly and disassembly of the device (attachment and detachment of members), and saving the space required for assembly and disassembly of the device. At least one of the attachment/detachment direction of the first flow path member 1 and the first component and the attachment/detachment direction of the second flow path member 2 and the second component is the direction in which the first flow path member 1 and the second flow path member 2 are aligned. You can also make it the same as (align). However, if the four members of the first component, the first flow channel member 1, the second flow channel member 2, and the second component are arranged in a line, the above advantages may be lost.

[Embodiment 9]
A detailed configuration of the family molding apparatus equipped with the backflow prevention valve shown in the first embodiment will be described. A family molding machine is an injection molding machine, which is equipped with a manufacturing unit such as a mold for taking multiple pieces of different shapes. The injection molding machine used in the family molding apparatus of this embodiment is of the in-line screw type, and can plasticize, inject, and measure the molding material by rotating, advancing, and retracting the screw as described later.

FIG. 17 shows a schematic cross-sectional view of the family forming apparatus 100 equipped with the backflow prevention valve 5. As shown in FIG. FIG. 17 shows a state in which the family molding apparatus 100 performs an injection process, which will be described later. In the description of the backflow prevention valve 5 shown in the drawing, the portions common to the description of the first embodiment will be omitted or simplified.

(Configuration of Family Molding Equipment)
The family molding apparatus 100 includes a molten resin supply section 30 and a manufacturing unit, and the manufacturing unit includes a first cavity 25, a second cavity 26, a hot runner 27, a plunger 28, and a pressure control device 29 that drives the plunger 28. . The first cavity 25 and the second cavity 26 are cavities for molding resin molded products having different shapes, and the inner volume of the first cavity 25 is larger than that of the second cavity 26 . Molten resin is supplied to the first cavity 25 and the second cavity 26 from a molten resin supply section 30 via a manifold-shaped hot runner 27 . A first gate valve 31 that can be opened and closed is provided at the tip of the injection nozzle 101 on the first cavity 25 side, and a second gate valve 32 that can be opened and closed is provided at the tip of the injection nozzle 102 on the second cavity 26 side. It is

In the hot runner 27, the flow path branched from the molten resin supply section 30 side to the first cavity 25 side is provided with the backflow prevention valve 5 shown in Embodiment 1 so that the molten resin supply section 30 faces the inflow side. is installed. That is, the backflow prevention valve 5 is mounted so that the direction from the molten resin supply portion 30 to the first cavity 25 is the forward flow direction. The anti-backflow valve 5 is sandwiched between the first flow path member 1 and the second flow path member 2 that constitute the hot runner 27, and as shown in FIG. 2 are fastened with bolts. Furthermore, a pressure sensor 23 for measuring the resin pressure in the flow path is installed in the first flow path member 1 .

The injection nozzle 101 installed between the second flow path member 2 and the first cavity 25 and the second flow path member 2 are separate members and are not fastened. A heater (not shown) is arranged in the injection nozzle 101 and the second flow path member 2, and the temperature is raised when the molten resin is flowed. Due to the thermal expansion of the injection nozzle 101 due to the temperature rise, the injection nozzle 101 and the second flow path member 2 are firmly in contact with each other. As a result, the molten resin is prevented from leaking from the contact portion between the injection nozzle 101 and the second channel member 2 .
The injection nozzle 102 and the first flow path member 1 are also configured in the same manner as described above, so that resin leakage does not occur at the contact portion between the injection nozzle 102 and the first flow path member 1 . Furthermore, a hot runner sprue 103 is installed between the first channel member 1 and the molten resin supply section 30 .

The hot runner sprue 103 and the first channel member are fastened with bolts (not shown).
During molding, the molten resin supply unit 30 is pressed against the hot runner sprue 103 . Due to this pressing force, the contact portion between the molten resin supply portion 30 and the hot runner sprue 103 and the contact portion between the molten resin supply portion and the first flow path member 1 are brought into firm contact, and resin leakage does not occur. there is
When replacing the backflow prevention valve 5, first, the mold member 104 and the mold member 105 are separated in the direction in which the mold members 104 and 105 are arranged (horizontal direction in FIG. 17), and the hot runner is replaced. 27 set is removed from the mold. Thereafter, the injection nozzles 101, 102, the hot runner sprue 103, and the hot runner 27 are separated in the direction in which the injection nozzles 101, 102, the hot runner sprue 103, and the hot runner 27 are aligned (horizontal direction in FIG. 17). As a result, the injection nozzle 101 , the injection nozzle 102 and the hot runner sprue 103 are removed from the hot runner 27 . After that, by removing the fastening bolts of the first flow path member 1 and the second flow path member 2 in the direction in which the first flow path member 1 and the second flow path member 2 are arranged (vertical direction in FIG. 17), The first channel member 1 and the second channel member 2 are separated. Thereby, the anti-backflow valve 5 can be removed from between the first channel member 1 and the second channel member 2 .

The first channel member 1 and the second channel member 2 are made of SUS material, and are provided with a heater (not shown) for maintaining the molten resin in the channel at an appropriate temperature (for example, 230°C). It is
The dimensions described with reference to FIGS. 1 and 2 were L1+L2=35 mm and LB=35.03 mm. The flange portions of the first flow path member 1 and the second flow path member 2 are fastened with 12 bolts 6 (for example, M12) with a tightening margin of TM=0.03 mm.
The housing 8 of the backflow prevention valve 5 (for example, a cylindrical outer diameter of φ30 mm) is made of SUS material, and the flow passage diameter at the position where the flow passage cross-sectional area is maximized is set to φ14 mm. The first valve seat portion 9 is made of high-speed steel having higher hardness than the SUS material of the first flow path member 1, and the diameter of the outer peripheral surface is set to 18 mm. Also, the first valve seat portion 9 was fitted to the housing 8 by shrink fitting. A valve chamber defined by the housing 8 and the first valve seat portion 9 has a spherical valve body 10 (for example, 10 mm in diameter) made of cemented carbide (a cemented carbide) inserted therein.

Assuming that the mold member 104 or the injection nozzle 101 is called a first component member and the mold member 105, injection nozzle 102 or hot runner sprue 103 is called a second component member, this embodiment has the following characteristic features. have a configuration. The first component is detachably connected to the first flow path member 1 and the second component is detachably connected to the second flow path member 2 . The attachment/detachment direction of the first flow path member 1 and the first component member (horizontal direction in FIG. 17) intersects the direction in which the first flow path member 1 and the second flow path member 2 are arranged (vertical direction in FIG. 17). there is The attachment/detachment direction of the second flow path member 2 and the second component member (horizontal direction in FIG. 17) intersects the direction in which the first flow path member 1 and the second flow path member 2 are arranged (vertical direction in FIG. 17). there is By doing so, there are advantages such as, for example, realizing miniaturization of the device, facilitating assembly and disassembly of the device (attachment and detachment of members), and saving the space required for assembly and disassembly of the device. At least one of the attachment/detachment direction of the first flow path member 1 and the first component and the attachment/detachment direction of the second flow path member 2 and the second component is the direction in which the first flow path member 1 and the second flow path member 2 are aligned. You can also make it the same as (align). However, if the four members of the first component, the first flow channel member 1, the second flow channel member 2, and the second component are arranged in a line, the above advantages may be lost.

[Other embodiments]
The present invention is not limited to the embodiments described above, and many modifications are possible within the technical concept of the present invention.
For example, the valve body used in the backflow prevention valve may be any member that can be displaced by fluid pressure and that can be in close contact with the first valve seat portion to close the flow path by fluid pressure in the reverse flow direction, and its shape is not necessarily spherical. Not limited.

Further, in the pre-plastic injection molding machine according to the second embodiment and the in-line screw type family molding machine according to the third embodiment, an example in which the backflow prevention valve according to the first embodiment is mounted has been shown, but of course the fourth to the implementation A backflow prevention valve according to Mode 7 may be implemented.

In addition, the target device to which the backflow prevention valve according to the embodiment is mounted is not limited to pre-plastic injection molding machines and in-line screw type family molding devices, but can be mounted to various devices equipped with flow paths for molten resin. can be done. For example, it can be mounted in molding machines of various types such as plunger type, pre-plasticizer type, plunger pre-plasticizer type, screw pre-plasticizer type, and screw type.

A device that includes members that define a flow path can be referred to as a flow path device. Although molten resin has been described as the fluid that flows through the flow path, the fluid that flows through the flow path is not limited to molten resin. Further, the target device (channel device) on which the backflow prevention valve according to the embodiment is mounted is not limited to a device having a channel for molten resin. It is sufficient if the valve body can be displaced by the pressure of the fluid flowing through the flow path of the target device. A device having a flow path for gas such as air may also be used.

1 First channel member/1C First channel section/2 Second channel member/2C Second channel section/3 Channel/5 Backflow prevention valve/6...bolt/7...valve chamber/8...housing/9...first valve seat/10...valve element/11...second valve seat /13...conical surface portion/14...boundary part/15...end face/17...screw/18...sleeve/19...nozzle/20...mold cavity/21 Plunger/22 Connecting portion/23 Pressure sensor/24 Switching valve/25 First cavity/26 Second cavity/27 Hot runner/28 Plunger/29 Pressure control device/30 Molten resin supply unit/31 First gate valve/32 Second gate valve/33 Screw/34A, 34B. Housing member/35 Bolt/36 Gap/37 Inflow port/38 Outflow port/50 Backflow prevention valve/51 Backflow prevention valve/52 Backflow prevention valve/53 Backflow prevention valve/80 Pre-plastic injection molding machine/81 Molten resin supply unit/82 Injection unit/100 Family molding device

Claims (20)

a first channel member defining a first section of the channel;
a second channel member defining a second section of the channel;
a valve unit capable of suppressing backflow in the flow path;
a fastening member capable of fastening the first flow path member and the second flow path member;
with
In a state where the first flow path member and the second flow path member are fastened by the fastening member, the valve unit is sandwiched between the first flow path member and the second flow path member, and the first section and The second section is connected via the valve unit,
In a state in which the first flow path member and the second flow path member are released from fastening by the fastening member, the valve unit is detachable from the first flow path member and the second flow path member.
A device characterized by: The first flow path member and the second flow path member are spaced apart and fastened via an interference of the fastening member,
2. A device according to claim 1, characterized in that: The tightening margin of the fastening member is 7 μm or more and 50 μm or less,
3. Apparatus according to claim 2, characterized in that: a first channel member defining a first section of the channel;
a second channel member defining a second section of the channel;
a valve unit capable of suppressing backflow in the flow path,
The first section and the second section are connected via the valve unit,
The valve unit includes a displaceable valve body and a first valve seat that can block the flow path when the valve body comes into contact with the valve body,
The first valve seat portion is in contact with the first flow path member, and is made of a material having a higher hardness than the material forming the first flow path member.
A device characterized by: The first valve seat portion is made of a material having a hardness (Rockwell hardness) of HRC 50 or more and less than 80,
The first flow path member is made of a material having a hardness (Rockwell hardness) of HRC 20 or more and less than 50.
5. Apparatus according to claim 4, characterized in that: The valve unit further comprises a housing in contact with the first valve seat,
The valve body is housed in a valve chamber defined by the housing and the first valve seat,
6. Apparatus according to claim 4 or 5, characterized in that: The housing includes a second valve seat portion that does not block the flow path when the valve body comes into contact with the valve seat.
7. Apparatus according to claim 6, characterized in that: The housing and the first valve seat are in contact with each other at a position where the flow passage cross-sectional area of the valve chamber is maximized.
8. Apparatus according to claim 6 or 7, characterized in that: The first flow path member is provided with a pressure sensor,
9. Apparatus according to any one of claims 1 to 8, characterized in that: The channel is a channel for molten resin,
10. Apparatus according to any one of the preceding claims, characterized in that: a first component detachably connected to the first channel member;
a second component detachably connected to the second flow path member,
The attachment/detachment direction of the first flow path member and the first component member and the attachment/detachment direction of the second flow path member and the second component member intersect the direction in which the first flow path member and the second flow path member are arranged. is doing,
11. Apparatus according to any one of claims 1 to 10, characterized in that: 12. A device comprising a device according to any one of claims 1 to 11, provided with a cavity,
A mold characterized by: A device according to any one of claims 1 to 11, a supply unit for supplying molten resin, and an injection unit for injecting molten resin,
The first flow path member and the second flow path member connect the supply section and the injection section,
An injection molding machine characterized by: A method for manufacturing a resin molded product using the injection molding machine according to claim 13,
having a weighing process, an injection process, and a holding pressure process,
The valve unit is in an open state in the weighing step,
The valve unit is closed during the injection step and the holding pressure step,
A method for manufacturing a resin molded product, characterized by: A device according to any one of claims 1 to 11, a supply unit for supplying molten resin, a first cavity, and a second cavity,
The first flow path member and the second flow path member are provided between the supply section and the first cavity in a manifold connecting the supply section and the first cavity and the second cavity. ,
A manufacturing unit characterized by: A method for manufacturing a resin molded product using the manufacturing unit according to claim 15,
having a weighing process, an injection process, and a holding pressure process,
The valve unit is in an open state in the metering process and the injection process,
The valve unit is closed in the holding pressure step,
A method for manufacturing a resin molded product, characterized by: A valve unit capable of suppressing backflow in a flow path,
a displaceable valve body; and a first valve seat portion capable of closing the flow path when the valve body abuts;
with
The first valve seat portion is made of a material having a hardness (Rockwell hardness) of HRC 50 or more and less than 80.
A valve unit characterized by: The valve unit further comprises a housing in contact with the first valve seat,
The valve body is housed in a valve chamber defined by the housing and the first valve seat,
18. The valve unit according to claim 17, characterized by: 19. The valve unit according to claim 18, wherein the housing is made of die steel, high-speed steel, or a SUS material with a hardness of HRC50-55. The housing includes a second valve seat portion that does not block the flow path when the valve body comes into contact with the valve seat.
20. The valve unit according to claim 18 or 19, characterized in that:

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