In-mold coating injection device

Abstract

The invention provides an in-mold coating injection device which is high in injection amount accuracy of a liquid coating agent (for example, paint), good in yield of the liquid coating agent and compact. The in-mold coating injection device (1) presses another mold (4) onto one mold (3) holding a molded base material (2) so as to cover the molded base material (2), and injects a predetermined amount of a coating material (6) into a coating gap (5) between the inner surface of the other mold (4) and the surface of the molded base material (2), by using a metering cylinder (9) of the coating material (6) as an extrusion cylinder of the coating material (6), according to the present invention, there is no need to connect the metering cylinder (9) and the extrusion cylinder, the injection port (8) is closed with the gate valve (14) when the paint (6) is introduced into the metering cylinder (9), the metering accuracy is improved, the device is made compact by not using a circulation loop and a circulation pump of the paint (6), and the material yield of the paint (6) is improved.

Description

Technical Field

[0001] The present invention relates to an in-mold coating injection device, which presses another mold on a mold holding a molding substrate to cover the molding substrate and injects a specified amount of liquid coating agent into a coating gap between the inner surface of the other mold and the surface of the molding substrate. Background Art

[0002] In recent years, as people's attention to environmental issues has increased, in-mold coating (IMC) has attracted attention as an alternative coating technology that does not use organic solvents and has a high effect on reducing carbon dioxide emissions. IMC is a technology that presses another mold on a mold holding a molding substrate to cover the molding substrate, and injects a liquid coating agent (for example, a thermosetting resin) into the coating gap between the inner surface of the other mold and the surface of the molding substrate, and forms a film on the outer surface of the molding substrate by heating.

[0003] The following are some of the characteristics of IMC: (1) Since organic solvents used in conventional spraying are not used, it is harmless to the environment and human body; (2) Equipment (injection, oven heat treatment) for the coating process is not required; (3) Since the paint is not diluted with organic solvents, the proportion of the material (paint) before coating that forms a coating film on the outer surface of the molded substrate (coating rate) is very high, and waste is minimal. IMC is used to improve the surface quality of molded products and simplify the coating process. In particular, it is widely used for exterior parts in the automotive industry, which has high requirements for appearance and quality.

[0004] Incidentally, in IMC, another mold is pressed on a mold holding a molding substrate so as to cover the molding substrate, and a liquid coating agent is injected into the coating gap while a coating gap is formed between the inner surface of the other mold and the surface of the molding substrate. Therefore, it is important to inject an appropriate amount of liquid coating agent that matches the volume of the coating gap.

[0005] If the liquid coating agent injected into the coating gap is smaller than the volume of the coating gap, an uncoated area will appear on part of the surface of the molded substrate (so-called short circuit). On the contrary, if the liquid coating agent injected into the coating gap is larger than the volume of the coating gap, excess liquid coating agent will leak from the parting surface between the molds (so-called overflow).

[0006] Therefore, in the prior art, an in-mold coating injection device for injecting a predetermined amount of liquid coating agent (thermosetting coating, etc., hereinafter also referred to as coating) into the coating gap has been developed (see Patent Document 1). Figure 6FIG. 7 shows an in-mold coating injection device, in which a metering cylinder is arranged in the middle of a circulation loop in which the paint circulates through a circulation pump, and an injection device for injecting a specified amount of paint measured by the metering cylinder into the coating gap is arranged in the circulation loop closer to the downstream side than the metering cylinder.

[0007] However, as described above, if a structure is adopted in which the metering cylinder and the injection device are separated and connected by piping, when the paint inside the metering cylinder is squeezed out and injected into the paint gap from the injection device, the pipe will expand slightly due to pressure loss in the pipe connecting the metering cylinder and the injection device, so that the quantitative accuracy of the injected paint cannot be expected. In particular, when the film thickness of the paint applied to the surface of the molding substrate is 0.1 mm or less, and the amount of paint injected into the coating gap each time is a small amount (for example, several CC), it is difficult to inject an appropriate amount of liquid coating agent that matches the volume of the coating gap, and the above-mentioned short circuit or overflow may occur depending on the use conditions.

[0008] In order to solve these problems, in patent document 1 Figure 1 , Figure 2 , describes an in-mold coating injection device, in which a metering and injection unit integrating the functions of a metering cylinder and an injection unit is provided in the middle of a circulation loop in which the paint circulates through a circulation pump, and a predetermined amount of paint is injected into a coating gap through the metering and injection unit. According to this configuration, since the paint is metered and injected through the metering and injection unit, pressure loss or expansion of the pipe connecting the metering cylinder and the injection unit as described above is not generated.

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent No. 3422843 Summary of the invention

[0012] Technical issues to be solved

[0013] However, Patent Document 1 Figure 1 , Figure 2 The described in-mold coating injection device suppresses the paint from receiving heat from the mold by circulating the paint in a circulation loop, and therefore requires a circulation loop and a circulation pump, which results in a larger and more complicated system.

[0014] In addition, after finishing a day's operation, in order to prevent the paint inside the circulation loop from hardening, it is necessary to discharge all the paint remaining in the circulation loop. Here, since the circulation loop needs to be provided with a circulation pump and a paint tank in the middle, the paint put into the device reaches a certain capacity. Therefore, if the amount of paint inside the circulation loop discharged at the end of a day's operation is compared with the amount of paint required for coating the molding substrate during a day's operation, it is impossible to say that the yield of the material (paint) is good. In particular, when the size of the molding substrate is small and the film thickness of the paint applied to the surface is less than 0.1mm, there is little paint required for coating, and the amount of paint remaining inside the circulation loop is relatively large, and the yield is extremely poor.

[0015] Furthermore, when a one-component curing thermosetting paint is used as the paint, when a curing initiator is mixed into the paint at the start of operation, a limitation of about 12 hours in the pot life (the time it takes to start curing even at room temperature) is created, and therefore the paint in the circulation loop must be discharged at the end of a day's operation, resulting in the need to perform a paint discharge operation and all the paint remaining in the circulation loop being wasted.

[0016] In addition, in Patent Document 1 Figure 1 , Figure 2 In the described in-mold coating injection device, the metering and injection space (hereinafter referred to as the cylinder) of the metering and injection portion is formed elongated, and the piston that rises and falls inside the cylinder is formed into an elongated rod shape. When the piston rises and the coating is introduced into the cylinder from the upper part of the cylinder, the injection port at the lower part of the cylinder is blocked by the surface of the molding substrate, so that a predetermined amount of coating remains in the cylinder. As described above, there is no gate valve to open and close the injection port at the lower part of the cylinder, and the injection port is blocked by the surface of the molding substrate in the mold to retain a predetermined amount of coating in the cylinder, so there is a possibility that the coating in the cylinder leaks from the injection port into the mold, and the quantitative accuracy may become a problem.

[0017] Furthermore, as described above, since the paint is retained in the cylinder by blocking the lower injection port of the cylinder with the molding substrate surface in the mold, and the molding substrate surface in the mold is used as a gate valve for the lower injection port of the cylinder, the cylinder needs to be embedded in the thick part of the mold so that the lower injection port of the cylinder is connected to the inner surface of the mold cavity. Therefore, the paint in the cylinder undergoes a curing reaction due to the heat from the mold, and when the piston is lowered to inject the paint in the cylinder from the injection port into the mold, it may not be injected properly into the corner.

[0018] The present invention is proposed in view of the above situation, and its purpose is to provide an in-mold coating injection device, which has high injection amount accuracy of liquid coating agent, good output of liquid coating agent and compact structure.

[0019] Solutions to the problem

[0020] According to the present invention proposed to achieve the above-mentioned purpose, there is provided an in-mold coating injection device, which presses another mold on a mold holding a molding substrate so as to cover the molding substrate, and injects a specified amount of liquid coating agent into the coating gap between the inner surface of the other mold and the surface of the molding substrate, characterized in that it includes: an injection device body, the injection device body is installed on the other mold; an injection port, the injection port is arranged at the front end of the injection device body, and is used to inject the liquid coating agent into the coating gap; a metering cylinder, the metering cylinder is connected to the injection port and is arranged inside the injection device body; a piston, the piston is able to move axially inside the metering cylinder; a supply port, the supply port is connected to the metering cylinder and is arranged on the side of the injection device body; a supply valve, The supply valve is arranged in a supply channel of a liquid coating agent connected to a supply port, and when the piston moves in a discharge direction that reduces the volume of a metering cylinder, the supply channel is closed, and when the piston moves in a suction direction that expands the volume of a metering cylinder, the supply channel is opened; a gate valve, wherein the gate valve is mounted on the piston in an axially slidable manner, and moves by sliding to an open valve position that opens the injection port and a closed valve position that closes the injection port; and an actuator, wherein the actuator sets the gate valve to a closed valve position, and moves the piston in a suction direction to introduce the liquid coating agent from the supply port into the metering cylinder, thereby filling the metering cylinder with a specified amount of liquid coating agent, and then, the actuator sets the gate valve to an open valve position, and moves the piston in a discharge direction, thereby discharging a specified amount of liquid coating agent from the injection port (Technical Solution 1).

[0021] In the in-mold coating injection device according to the present invention, the supply valve can be a check valve, which allows the liquid coating agent to flow from the supply channel to the metering cylinder and prevents the liquid coating agent from flowing from the metering cylinder to the supply channel (Technical Solution 2).

[0022] In the in-mold coating injection device according to the present invention, the actuator includes: a piston actuating flange, which is formed on a portion of the piston protruding from the metering cylinder in order to move the piston along the axial direction of the metering cylinder; a piston actuating cylinder, which accommodates the piston actuating flange capable of moving along the axial direction of the metering cylinder; a gate valve actuating flange, which is formed on a portion of the gate valve protruding from the piston in order to move the gate valve along the axial direction of the piston; and a gate valve actuating cylinder, which is connected to the piston actuating cylinder. cylinder, and accommodating a gate valve actuating flange that can move along the axial direction of the piston; and a fluid pressure switching mechanism, which can switch between a metering mode and an injection mode, wherein the metering mode refers to the gate valve closing the injection port and the piston moving in the suction direction by applying fluid pressure to the upper surface of the gate valve actuating flange and the lower surface of the piston actuating flange, and the injection mode refers to the gate valve opening the injection port and the piston moving in the discharge direction by applying fluid pressure to the lower surface of the gate valve actuating flange and the upper surface of the piston actuating flange (Technical Solution 3).

[0023] In the in-mold coating injection device of the present invention, the liquid coating agent is a single-component curing thermosetting coating, and a cooling water channel is formed inside the injection device body to surround the flow path of the liquid coating agent discharged from the metering cylinder to the injection port (Technical Solution 4).

[0024] Effects of the Invention

[0025] According to the in-mold coating injection device of the present invention, the following effects can be achieved.

[0026] (1) By using the metering cylinder for the liquid coating agent also as the extrusion cylinder for the liquid coating agent, it is not necessary to connect the pipes of the metering cylinder and the extrusion cylinder. When the liquid coating agent is introduced into the metering cylinder, the injection port is closed by the gate valve, thereby improving the discharge accuracy of the liquid coating agent.

[0027] (2) Since the liquid coating agent introduced from the supply port into the metering cylinder through the supply channel is squeezed out from the injection port by a piston and the circulation loop and circulation pump of the liquid coating agent described in the prior art are not used, there is no need to remove the paint remaining in the circulation loop and the circulation pump for disposal after the operation is completed, thereby increasing the material output of the liquid coating agent.

[0028] (3) Since a circulation circuit and a circulation pump for the liquid coating agent are not used, the entire device can be constructed compactly and the material throughput of the liquid coating agent can be increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 : is a cross-sectional view showing the entire system of an in-mold coating injection device according to one embodiment of the present invention.

[0030] Figure 2 yes Figure 1 A cross-sectional view of the in-mold coating injection device is shown when metering begins.

[0031] Figure 3 It is the successor Figure 2 Cross-sectional view at the end of measurement.

[0032] Figure 4 It is the successor Figure 3 Cross-section at the start of injection.

[0033] Figure 5 It is the successor Figure 4 Cross-section at the end of injection.

[0034] Figure 6 1 and 2 are explanatory diagrams showing cooling water passages, wherein (a) is a perspective view and (b) is a cross-sectional view. DETAILED DESCRIPTION

[0035] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials and other specific values ​​shown in the embodiments involved are only examples for facilitating understanding of the present invention and do not limit the present invention unless otherwise specified. In addition, in this specification and the accompanying drawings, for elements having substantially the same function and structure, repeated descriptions are omitted by assigning the same reference numerals, and illustrations of elements that are not directly related to the present invention are omitted.

[0036] (Overview of In-Mold Coating Injection Device 1)

[0037] like Figure 1 As shown, according to the in-mold coating injection device 1 of the present invention, another mold 4 is pressed onto a mold 3 holding a molding substrate 2 so as to cover the molding substrate 2, and a specified amount of liquid coating agent 6 is injected into the coating gap 5 between the inner surface of the other mold 4 and the surface of the molding substrate 2.

[0038] If enlarged Figure 1 The main part Figure 2As shown, an in-mold coating injection device 1 according to an embodiment of the present invention includes: an injection device body 7, which is installed on another mold 4; an injection port 8, which is arranged at the front end of the injection device body 7 and is used to inject the liquid coating agent 6 into the coating gap 5; a metering cylinder 9, which is connected to the injection port 8 and is arranged inside the injection device body 7; a piston 10, which can move axially inside the metering cylinder 9; a supply port 11, which is connected to the metering cylinder 9 and is arranged on the side of the injection device body 7; a supply valve 13, which is arranged in a supply channel 12 of the liquid coating agent 6 connected to the supply port 11, when the piston 10 moves in the discharge direction of reducing the volume of the metering cylinder 9, the supply valve 13 closes the supply channel 12, and when the piston 10 moves in the suction direction of expanding the volume of the metering cylinder 9, the supply valve 13 opens the supply channel 12.

[0039] In addition, if Figure 2 As shown, the in-mold coating injection device 1 according to this embodiment further includes a gate valve 14 and an actuator 15. The gate valve 14 is mounted on the piston 10 in a manner that can slide in the axial direction, and moves to an open valve position for opening the injection port 8 and a closed valve position for closing the injection port 8 by sliding. The actuator 15 is composed of the following: Figures 2 to 3 As shown, the gate valve 14 is set to the closed valve position, and the piston 10 is moved in the suction direction to introduce the liquid coating agent 6 from the supply port 11 into the metering cylinder 9, so that a predetermined amount of the liquid coating agent 6 is filled in the metering cylinder 9, and then, as shown in FIG. Figures 4 to 5 As shown, the gate valve 14 is set to the open position, and the piston 10 is moved in the discharge direction, so that a predetermined amount of the liquid coating agent 6 is discharged from the injection port 8. Hereinafter, each component will be described.

[0040] (Mold, coating gap 5)

[0041] like Figure 1 As shown, the mold includes: a mold 3 (hereinafter also referred to as the lower mold 3), on which a convex core 16 is provided, and a molded substrate 2 formed separately is mounted on the core 16; another mold 4 (hereinafter also referred to as the upper mold), which is arranged opposite to the one mold 3 and has a cavity 17 concavely provided therein so as to form a prescribed coating gap 5 (for example, 50 μm to 100 μm) between the upper mold 4 and the outer surface of the molded substrate of the core 16 mounted on the lower mold 3. The upper mold 4 is mounted on the lower surface of the upper platen 18 via a heat insulation plate 52 with bolts not shown, and the lower mold 3 is mounted on the upper surface of the lower platen 19 with bolts not shown. The lower platen 19 moves in the up-down direction relative to the upper platen 18, so that the lower mold 3 approaches and moves away from the upper mold 4, thereby closing and opening the mold.

[0042] like Figure 1 As shown, a flow channel groove 20 is formed on the facing surface (parting surface) of the upper mold 4 and the lower mold 3, which is used to supply a liquid coating agent 6 (for example, a one-component curing thermosetting coating, hereinafter also referred to as coating) to the coating gap 5 between the outer surface of the molding substrate 2 and the inner surface of the cavity 17 of the upper mold 4 when the mold is closed. The flow channel groove 20 accommodates a flow channel 2a, which is generated when the molding substrate 2 is molded by another molding mold (not shown) instead of the upper mold 4. Figure 4 , Figure 5 As shown, the coating material 6 passes through the flow channel groove 20 and is injected into the coating gap 5 along the flow channel 2a. In order to heat the coating material 6 injected into the coating gap 5 through the flow channel groove 20 and harden it, the upper mold 4 is provided with a heating mechanism (resistance wire, etc.) not shown. The heat insulation plate 52 provided between the upper mold 4 and the upper pressing plate 18 plays a function of inhibiting the heat of the upper mold 4 from being transferred to the upper pressing plate 18. Accordingly, the heat transferred from the upper pressing plate 18 to the injection device body 7 is reduced, thereby inhibiting the progress of the curing reaction of the coating material 6 (single-component curing type thermosetting coating material) introduced into the interior of the injection device body 7 (cylinder 9).

[0043] (Injection device body 7)

[0044] like Figure 2 As shown, in this embodiment, the injection device body 7 is composed of a three-stage cylinder of a small diameter portion 7a, a middle diameter portion 7b and a large diameter portion 7c connected from bottom to top, and has a mounting flange 43 arranged on the outer peripheral surface of the large diameter portion 7c. The mounting flange 43 is mounted on the upper pressing plate 18 by bolts 44. A mounting hole 21 for accommodating the injection device body 7 is formed in the upper mold 4 in a manner that penetrates the upper and lower surfaces so as to be connected to the flow channel groove 20. The mounting hole 21 is composed of a small diameter hole portion 21a corresponding to the small diameter portion 7a of the injection device body 7 and a middle diameter hole portion 21b having a hole diameter larger than the middle diameter portion 7b of the injection device body 7, and a prescribed gap 54 is formed between the middle diameter hole portion 21b and the middle diameter portion 7b. The gap 54 is used as an air heat insulation layer to inhibit the heat of the upper mold 4 from being transferred to the injection device body 7.

[0045] like Figure 2 As shown, in order to accommodate the large diameter portion 7c of the injection device body 7, the upper pressing plate 18 is formed with a through hole 24 having a hole diameter larger than the large diameter portion 7c. A gap 25 is formed between the through hole 24 and the large diameter portion 7c of the injection device body 7, and the gap 25 serves as an air heat insulation layer to suppress the small amount of heat transferred from the upper mold 4 to the upper pressing plate 18 via the heat insulation plate 52 from being transferred to the injection device body 7.

[0046] like Figure 2As shown, a heat insulating sleeve 22 is provided between the small diameter portion 7a of the injection device body 7 and the small diameter hole portion 21a of the mounting hole 21. The heat insulating sleeve 22 inhibits the heat of the upper mold 4 from being transferred to the injection device body 7, and inhibits the curing reaction of the coating 6 (single component curing type thermosetting coating) introduced into the injection device body 7. A heat insulating flange 22a is integrally provided at the upper end of the heat insulating sleeve 22. The heat insulating flange 22a is formed in a manner of being sandwiched between the step from the small diameter portion 7a to the middle diameter portion 7b of the injection device body 7 and the step from the small diameter hole portion 21a to the middle diameter hole portion 21b of the mounting hole 21, inhibiting the heat of the upper mold 4 from being transferred to the injection device body 7, thereby inhibiting the coating 6 (single component curing type thermosetting coating) introduced into the injection device body 7 from receiving the heat from the upper mold 4 and undergoing a curing reaction. Furthermore, when the bolt 44 is tightened, the heat insulating flange 22a is sandwiched between the steps and slightly contracts, thereby preventing the paint 6 in the flow channel groove 20 from leaking upward from between the mounting hole 21 and the injection device body 7, so that the heat insulating flange 22a acts as a sealing gasket.

[0047] like Figure 2 As shown, a heat insulating ring 23 is provided between the step from the large diameter portion 7c to the middle diameter portion 7b of the injection device body 7 and the upper surface of the upper mold 4, and the heat insulating ring 23 inhibits the heat of the upper mold 4 from being transferred to the injection device body 7. The heat insulating ring 23 inhibits the heat of the upper mold 4 from being transferred to the injection device body 7, thereby inhibiting the paint 6 (single-component curing type thermosetting paint) introduced into the injection device body 7 from receiving the heat from the upper mold 4 and undergoing a curing reaction. In addition, when the bolt 44 is tightened, the heat insulating ring 23 is sandwiched between the lower surface of the large diameter portion 7c and the upper surface of the upper mold 4 and slightly contracts, and through its restoring force, the external thread portion of the bolt 44 and the internal thread portion of the screw hole for the bolt 44 formed in the upper pressing plate 18 are pressed against each other in the axial direction, so that the heat insulating ring 23 serves as a loosening prevention material for the bolt 44. Furthermore, similarly, when the bolt 44 is tightened, the heat insulating flange 22 a of the heat insulating sleeve 22 also contracts slightly to exert a restoring force, so the heat insulating flange 22 a of the heat insulating sleeve 22 also serves as a loosening prevention material for the bolt 44 .

[0048] (Metering cylinder 9, piston 10)

[0049] like Figure 2As shown, a metering cylinder 9 for accommodating a specified amount of coating material 6 is formed inside the injection device body 7. The metering cylinder 9 is formed inside the large diameter portion 7c of the injection device body 7, and the metering cylinder 9 is arranged at a position least susceptible to the heat from the upper mold 4 inside the injection device body 7 through the above-mentioned insulation sleeve 22, insulation ring 23, gap 25 (air insulation layer), and gap 54 (air insulation layer). In this embodiment, the metering cylinder 9 is arranged at a position closer to the top than the upper surface of the upper mold 4 and closer to the top than the insulation ring 23. A piston 10 is arranged inside the metering cylinder 9, and the piston 10 can move in the axial direction (up and down direction). The piston 10 includes: a piston body portion 10a, the piston body portion 10a having a diameter that slides in the metering cylinder 9; and a piston protrusion 10b, the piston protrusion 10b is arranged at a portion protruding from the metering cylinder 9 on the upper part of the piston body portion 10a.

[0050] (Injection port 8, supply port 11)

[0051] like Figure 2 As shown, a channel hole 26 is formed inside the middle diameter portion 7b and the small diameter portion 7a of the injection device body 7, and the channel hole 26 is connected to the metering cylinder 9 and has a smaller diameter than the metering cylinder 9. A conical valve seat 27 is formed at the lower end of the channel hole 26, and an injection port 8 is formed at the lower end of the valve seat 27 in a manner facing the flow channel groove 20. The injection port 8 is used to inject the paint 6 in the metering cylinder 9 into the flow channel groove 20 through the channel hole 26, and is closed when the lower end of the gate valve 14 is seated on the valve seat 27, and is opened when the lower end of the gate valve 14 is separated from the valve seat 27. In addition, a supply port 11 connected to the metering cylinder 9 is provided on the side of the large diameter portion 7c of the injection device body 7, which is used to supply the paint 6 to the metering cylinder 9.

[0052] (Supply channel 12)

[0053] like Figure 2 As shown, a supply channel 12 is connected to the supply port 11 on the side of the large diameter portion 7c of the injection device body 7, and is used to supply the paint 6 to the metering cylinder 9. The supply channel 12 is inserted into a hole formed inside the upper pressing plate 18, and the diameter of the hole is larger than the outer diameter of the supply channel 12. A gap 53 is formed between the hole and the supply channel 12. The gap 53 is used as an air isolation layer to inhibit the heat of the upper pressing plate 18 from being transferred to the paint 6 flowing through the supply channel 12.

[0054] (Supply valve 13)

[0055] exist Figure 1 The supply passage 12 shown is provided with a supply valve 13, such as Figures 2 to 3 As shown, when the piston 10 moves in the suction direction (upward) to expand the volume of the metering cylinder 9, the supply valve 13 opens the supply passage 12, as shown in FIG. Figures 4 to 5 As shown, when the piston 10 moves in the discharge direction (downward) to reduce the volume of the metering cylinder 9, the supply valve 13 closes the supply passage 12. In the present embodiment, the supply valve 13 uses a check valve, which allows the paint 6 to flow from the supply passage 12 to the metering cylinder 9 and prevents the paint 6 from flowing from the metering cylinder 9 to the supply passage 12, but the supply passage 12 may also be opened and closed by a switch valve controlled to open and close as described above. Figure 1 As shown, a coating material tank 28 containing the coating material 6 is connected to the upstream side of the supply valve 13 via a pipe 29 .

[0056] (Gate valve 14)

[0057] like Figure 2 As shown in FIG. 1 , a hole 30 is formed through the piston 10 in the axial direction (in the vertical direction), and a gate valve 14 is mounted on the hole 30 in a manner that can slide in the axial direction. The gate valve 14 includes a middle diameter portion 14a having a diameter that can slide in the hole 30, a small diameter portion 14b that is integrally provided at the lower part of the middle diameter portion 14a, and a large diameter portion 14c that is integrally provided at the upper part of the middle diameter portion 14a. The small diameter portion 14b is accommodated in the passage hole 26 at a predetermined interval in the diameter direction, and has a front end valve portion 14d formed in a conical shape at its lower end so as to be seated on the valve seat 27. The large diameter portion 14c has a diameter that allows it to slide in a hole 31 formed in the piston protrusion 10b in the axial direction, and its upper part protrudes upward from the piston protrusion 10b. When the gate valve 14 rises, the front end valve portion 14d leaves the valve seat 27, so that the gate valve 14 is in an open valve position opening the injection port 8. When the gate valve 14 descends, the front end valve portion 14d sits on the valve seat 27, so that the gate valve 14 is in a closed valve position closing the injection port 8.

[0058] (Actuator 15)

[0059] like Figure 1 As shown, the piston 10 and the gate valve 14 are appropriately raised and lowered by the actuator 15. Figures 2 to 3 As shown, the actuator 15 lowers the gate valve 14 to the closed valve position and raises the piston 10 to move in the suction direction, and introduces the liquid coating agent 6 from the supply port 11 into the metering cylinder 9, so that a predetermined amount of the liquid coating agent 6 is filled in the metering cylinder 9. Then, as shown in FIG. Figures 4 to 5 As shown, the gate valve 14 is raised to the open valve position, and the piston 10 is lowered to move in the discharge direction, so that a predetermined amount of the liquid coating agent 6 is discharged from the injection port 8 .

[0060] like Figure 2As shown, the actuator 15 includes: a piston actuating flange 32, which is formed on a portion of the piston 10 protruding from the metering cylinder 9 (piston protrusion 10b) in order to enable the piston 10 to move axially along the metering cylinder 9; a piston actuating cylinder 33, which accommodates the piston actuating flange 32 capable of moving axially along the metering cylinder 9; a gate valve actuating flange 34, which is formed on a portion of the gate valve 14 protruding from the piston 10 (gate valve protrusion 14e) in order to enable the gate valve 14 to move axially along the piston 10; and a gate valve actuating cylinder 35, which is connected to the piston actuating cylinder 33 and accommodates the gate valve actuating flange 34 capable of moving axially along the piston 10.

[0061] like Figure 2 As shown, the piston actuating cylinder 33 and the gate valve actuating cylinder 35 are respectively formed inside a cylinder body 37 mounted on the upper platen 18 via a support 36. The cylinder body 37 includes: a first channel 38 for applying fluid pressure to the upper surface of the gate valve actuating flange 34 and the lower surface of the piston actuating flange 32; and a second channel 39 for applying fluid pressure to the lower surface of the gate valve actuating flange 34 and the upper surface of the piston actuating flange 32. The first channel 38 includes: a channel 38a connecting a hole formed on one side of the cylinder body 37 and a portion of the gate valve actuating cylinder 35 that is closer to the upper side than the gate valve actuating flange 34; and a channel 38b connecting the middle of the channel 38a and a portion of the piston actuating cylinder 33 that is closer to the lower side than the piston actuating flange 32. The second passage 39 connects a hole formed in the other side surface of the cylinder block 37 and a portion above the piston actuating flange 32 of the piston actuating cylinder 33 .

[0062] In addition, the actuator 15 includes a fluid pressure switching mechanism 40 (see Figure 1 ), wherein the metering mode refers to, Figures 2 to 3 As shown, by supplying fluid (air, water, oil, etc.) to the first channel 38, fluid pressure is applied to the upper surface of the gate valve actuating flange 34 and the lower surface of the piston actuating flange 32, so that the gate valve 14 closes the injection port 8 and the piston 10 moves in the suction direction. The injection mode refers to, for example, Figures 4 to 5 As shown, by supplying fluid to the second passage 39 , fluid pressure is applied to the lower surface of the gate valve actuating flange 34 and the upper surface of the piston actuating flange 32 , so that the gate valve 14 opens the injection port 8 and the piston 10 moves in the discharge direction.

[0063] (Fluid Pressure Switching Mechanism 40)

[0064] like Figure 1As shown, the fluid pressure switching mechanism 40 includes: a switching valve 41 connected to the first passage 38 and the second passage 39; a tank T (gas tank, water tank, oil tank, etc.) containing a fluid (air, water, oil, etc.) at a predetermined pressure in order to supply fluid pressure (gas pressure, water pressure, hydraulic pressure, etc.); a pump P that pressurizes the fluid and supplies it to the tank T; and a control unit C that appropriately switches the switching valve 41. In this embodiment, an example of using air as the fluid and using an electromagnetic solenoid valve as the switching valve 41 is shown.

[0065] exist Figure 1 In the electromagnetic solenoid valve (switching valve 41) shown in FIG. 1 , when the solenoid 41a of the switching valve 41 is not powered from the control unit C, the box is pushed to the right by the spring 41b and is in a parallel circuit working state. As a result, the air in the tank T is supplied to the first passage 38, and the air in the second passage 39 is discharged from the exhaust muffler 42. Figures 2 to 3 As shown, the gate valve 14 is lowered to be in the closed valve position, and the piston moves upward (intake direction), thereby being in the metering mode.

[0066] On the other hand, when Figure 1 When the control unit C shown in the figure supplies power to the solenoid 41a, the solenoid 41a is excited and the box moves to the left, thereby being in a cross circuit working state. As a result, the air in the tank T is supplied to the second passage 39, and the air in the first passage 38 is discharged from the exhaust muffler 42. Figures 4 to 5 As shown, the gate valve 14 is raised to be in the open valve position, and the piston moves downward (in the discharge direction), thereby being in the injection mode.

[0067] (Cooling water channel)

[0068] like Figure 6 As shown in (a), a cooling water channel 45 is formed inside the injection device body 7, and the cooling water channel 45 surrounds the flow path of the liquid coating agent 6 (single-component curing type thermosetting paint) discharged from the injection port through the metering cylinder 9 and the channel hole 26. The cooling water channel 45 is formed in a double helical shape so that the cooling water introduced from the inlet 46 formed on the upper left side of the injection device body 7 around the metering cylinder 9 and the channel hole 26, descends counterclockwise when viewed from above, turns back at the lower part of the injection device body 7 and rises clockwise, and is discharged from the outlet 47 formed on the upper right side of the injection device body 7. The injection device body 7 formed with such a complex shape of the cooling water channel 45 is manufactured by a metal 3D printer, lost wax casting, etc. The liquid coating agent 6 (single-component curing type thermosetting paint) contained in the metering cylinder 9 and the channel hole 26 is overheated by the heat from the upper mold 4, thereby suppressing the progress of the curing reaction.

[0069] (Start measuring)

[0070] When a predetermined amount of coating material 6 is introduced into Figure 1 When the in-mold coating injection device 1 is shown, first, Figure 2 As shown, the fluid is supplied to the first channel 38. Then, the gate valve 14 descends and is in the closed valve position, and the piston 10 rises. Accordingly, the metering cylinder 9 is in a negative pressure, and the paint 6 is introduced into the metering cylinder 9 via the supply valve 13 (check valve). Here, if the front end valve portion 14d of the gate valve 14 separates from the valve seat 27, the paint 6 will leak from the injection port 8, so the top surface of the cylinder body 37 is provided with a leak-proof spring 48 for pushing the gate valve 14 downward and pushing the front end valve portion 14d toward the valve seat 27. Therefore, even if the control cannot be achieved due to a failure of the actuator 15 or an emergency stop, the paint 6 in the device will not leak into the mold. In addition, the fluid in the piston actuating cylinder 33 that is closer to the top than the piston actuating flange 32 is discharged from the second channel 39 as the piston actuating flange 32 rises.

[0071] (End of measurement)

[0072] like Figure 3 As shown, the piston actuating flange 32 of the piston 10 contacts the top surface of the piston actuating cylinder 33, so that the piston 10 reaches the top dead center, and a specified amount of paint 6 remains in the metering cylinder 9, and metering is completed.

[0073] (Start injection)

[0074] Next, in order to inject a predetermined amount of coating material 6 from the injection port 8 into the flow channel 20, as shown in FIG. Figure 4 As shown, the fluid is supplied to the second channel 3. Then, the gate valve 14 rises to open the injection port 8, and the piston 10 descends to reduce the volume of the metering cylinder 9. As a result, the paint 6 in the metering cylinder 9 is injected from the injection port 8 into the flow channel groove 20. At this time, the supply valve 13 (check valve) prevents the paint 6 in the metering cylinder 9 from flowing into the tank body 28 (refer to Figure 1 In addition, the fluid in the piston actuating cylinder 33 that is lower than the piston actuating flange 32 is discharged from the first passage 38 as the piston actuating flange descends, and the fluid in the gate valve actuating cylinder 35 that is higher than the gate valve actuating flange 32 is discharged from the first passage 38 as the gate valve actuating flange rises.

[0075] (End of injection)

[0076] like Figure 5As shown, the lower surface of the stroke adjustment ring 49 provided on the piston 10 contacts the upper surface of the injection device body 7, so that the piston 10 reaches the bottom dead center and the injection of the coating material 6 is terminated. By appropriately changing the thickness t of the stroke adjustment ring 49, the stroke S from the top dead center to the bottom dead center can be adjusted (refer to Figure 3 ), and thus the injection amount of the paint 6 can be adjusted. On the other hand, the gate valve 14 contacts the bottom surface of the stop bolt 51 screwed into the threaded hole 50 penetrating the top surface of the cylinder body 37, thereby positioning the valve opening position. By appropriately changing the screwing position of the stop bolt 51, the distance between the front end valve portion 14d of the gate valve 14 in the valve opening position and the valve seat 27 can be adjusted, thereby adjusting the discharge rate (discharge amount per unit time) of the paint 6 discharged from the injection port 8.

[0077] (Function / Effect)

[0078] According to the in-mold coating injection device 1 of this embodiment, by Figures 2 to 3 The metering cylinder 9 of the coating material 6 shown is also used as Figures 4 to 5 The extrusion cylinder of the paint 6 shown does not need to connect the pipes of the metering cylinder 9 and the extrusion cylinder. When the paint 6 is introduced into the metering cylinder 9, the injection port 8 is closed by the gate valve 14, thereby improving the metering accuracy of the paint 6.

[0079] In addition, if Figure 1 As shown, since the paint 6 introduced from the supply port 11 into the metering cylinder 9 through the supply channel 12 is squeezed out from the injection port 8 by the piston 10 and the paint circulation loop and circulation pump described in the prior art are not used, there is no need to remove the paint remaining in the circulation loop and circulation pump for disposal after the operation is completed, thereby increasing the material output of the paint 6.

[0080] In addition, since the paint circulation loop and circulation pump are not used, the entire device can be compact and the material yield of the paint 6 can be increased. As described above, according to the in-mold coating injection device 1 of this embodiment, the injection amount of the paint 6 is highly accurate, the yield of the paint 6 is good, and it is compact.

[0081] The preferred embodiments of the present invention have been described above with reference to the accompanying drawings. Of course, the present invention is not limited to the above embodiments, and it goes without saying that various changes or modifications within the scope of the claims also belong to the technical scope of the present invention.

[0082] Industrial Applicability

[0083] The present invention can be used in an in-mold coating injection device, which presses another mold on a mold holding a molding substrate to cover the molding substrate and injects a specified amount of liquid coating agent into a coating gap between the inner surface of the other mold and the surface of the molding substrate.

[0084] (Explanation of Reference Numerals)

[0085] 1 In-mold coating injection device

[0086] 2 Forming substrate

[0087] 3. One mold (lower mold)

[0088] 4 Another mold (upper mold)

[0089] 5 Coating gap

[0090] 6Liquid coating agent (paint)

[0091] 7 Injection device body

[0092] 8 Inlet

[0093] 9 Metering cylinder

[0094] 10 Piston

[0095] 11 Supply port

[0096] 12 Supply Channel

[0097] 13 Supply valve (check valve)

[0098] 14. Gate valve

[0099] 15 Actuator

[0100] 32 Piston actuating flange

[0101] 33 Cylinder for piston actuation

[0102] 34 Gate valve actuating flange

[0103] 35 Cylinder for gate valve actuation

[0104] 40 Fluid pressure switching mechanism

[0105] 45 Cooling water channel

Claims

1. An in-mold coating injection device, which presses another mold on a mold holding a molding substrate so as to cover the molding substrate, and injects a specified amount of liquid coating agent into a coating gap between the inner surface of the other mold and the surface of the molding substrate, characterized in that: include: an injection device body, the injection device body being mounted on the other mold; An injection port, the injection port is arranged at the front end of the injection device body, and is used to inject the liquid coating agent into the coating gap; A metering cylinder connected to the injection port and disposed inside the injection device body; A piston capable of axially moving inside the metering cylinder; a supply port, the supply port being connected to the metering cylinder and being disposed on a side of the injection device body; a supply valve, the supply valve being provided in a supply passage of the liquid coating agent connected to the supply port, closing the supply passage when the piston moves in a discharge direction for reducing the volume of the metering cylinder, and opening the supply passage when the piston moves in a suction direction for expanding the volume of the metering cylinder; a gate valve, the gate valve being mounted on the piston in a manner capable of sliding in the axial direction, and moving to an open valve position for opening the injection port and a closed valve position for closing the injection port by sliding; and An actuator sets the gate valve to the closed valve position and moves the piston in the suction direction to introduce the liquid coating agent from the supply port into the metering cylinder, thereby filling the metering cylinder with a specified amount of the liquid coating agent, and then sets the gate valve to the open valve position and moves the piston in the discharge direction, thereby discharging the specified amount of the liquid coating agent from the injection port.

2. The in-mold coating injection device according to claim 1, characterized in that: The supply valve is a check valve that allows the liquid coating agent to flow from the supply passage to the metering cylinder and prevents the liquid coating agent from flowing from the metering cylinder to the supply passage.

3. The in-mold coating injection device according to claim 1 or 2, characterized in that: The actuator comprises: a piston actuating flange formed on a portion of the piston protruding from the metering cylinder in order to move the piston in the axial direction of the metering cylinder; a piston actuating cylinder accommodating the piston actuating flange movable in the axial direction of the metering cylinder; a gate valve actuating flange formed on a portion of the gate valve protruding from the piston in order to move the gate valve in the axial direction of the piston; a gate valve actuating cylinder connected to the piston actuating cylinder and accommodating the gate valve actuating flange movable in the axial direction of the piston; and A fluid pressure switching mechanism, wherein the fluid pressure switching mechanism can switch between a metering mode and an injection mode, wherein the metering mode refers to the gate valve closing the injection port and the piston moving along the suction direction by applying fluid pressure to the upper surface of the gate valve actuating flange and the lower surface of the piston actuating flange, and the injection mode refers to the gate valve opening the injection port and the piston moving along the discharge direction by applying fluid pressure to the lower surface of the gate valve actuating flange and the upper surface of the piston actuating flange.

4. The in-mold coating injection device according to claim 3, characterized in that: The liquid coating agent is a one-component curing thermosetting coating, A cooling water channel is formed inside the injection device body so as to surround a flow path of the liquid coating agent discharged from the metering cylinder to the injection port.

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