Foaming injection mold and control method thereof

Abstract

The invention provides a foaming injection mold and a control method thereof.The foaming injection mold comprises a movable mold body and a fixed mold body, the movable mold body can be driven by a mold moving oil cylinder to move close to or away from the fixed mold body so as to achieve mold closing and mold opening, and when the movable mold body and the fixed mold body are closed, a cavity is formed between the movable mold body and the fixed mold body; the sealing ring is arranged around the periphery of the forming cavity and has a material injection state and a pressure maintaining and shaping state when the movable mold and the fixed mold are closed, and the distance between the movable mold and the fixed mold in the material injection state is larger than the distance between the movable mold and the fixed mold in the pressure maintaining and shaping state; and the sealing ring can block a parting surface gap of the cavity in a material injection state and a pressure maintaining and shaping state. According to the invention, the foaming material is effectively prevented from leaking from the gap of the parting surface when the movable mold is slightly opened, the material waste is effectively avoided, the tidiness of a production space is ensured, and the final quality of an injection product is ensured at the same time.

Description

Technical Field

[0001] The invention belongs to the technical field of injection molding equipment design, and particularly relates to a foaming injection mold and a control method thereof. Background Art

[0002] For the current micro-foaming injection molding process, in the relevant technology, in order to ensure product quality, after the movable mold and the fixed mold are closed, the movable mold will be controlled to be a certain small distance away from the fixed mold (generally 2-3mm), so as to improve the parallelism of the movable mold plate and the fixed mold plate, and to increase the mold cavity capacity, thereby ensuring that the injection amount of the foaming material reaches the required amount of the molded product. The above-mentioned control process is also the micro-opening control of the mold. During the micro-opening of the mold, due to the lack of necessary sealing structure for the parting surface gap between the movable and fixed molds, the injection molding material injected during the micro-opening of the mold is very easy to leak out from the parting surface gap, which also causes material leakage, wastes material, reduces the cleanliness of the production space, and reduces the quality of the injection molded products. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to provide a foaming injection mold and a control method thereof, which can overcome the technical problem in the prior art that the foaming injection mold leaks material at the parting surface gap during the micro-opening process of the mold, wastes material, reduces the cleanliness of the production space, and reduces the quality of the injection molded products.

[0004] In order to solve the above problems, the present invention provides a foaming injection mold, including a movable mold and a fixed mold. The movable mold can be moved closer to or away from the fixed mold under the drive of the mold-moving cylinder to achieve mold closing and mold opening. When the movable mold and the fixed mold are closed, a cavity is formed between the two. It also includes a sealing ring arranged around the periphery of the molding cavity. When the movable mold and the fixed mold are closed, there are a material injection state and a pressure holding and molding state. The distance between the movable mold and the fixed mold in the material injection state is greater than the distance between the movable mold and the fixed mold in the pressure holding and molding state, and the sealing ring can block the parting surface gap of the cavity in both the material injection state and the pressure holding and molding state.

[0005] In some embodiments, the foaming injection mold also includes a plurality of sealing cylinders with parallel oil circuits and a control oil circuit module for controlling the synchronous extension and retraction of the sealing piston rods of the sealing cylinders. The cylinder body of each sealing cylinder is assembled on the movable mold, and the free end of the sealing piston rod of each sealing cylinder is connected to the sealing ring. The control oil circuit module is used to control the sealing piston rod of each sealing cylinder to apply force to the sealing ring to keep the sealing ring in sealing contact with the parting surface of the fixed mold during the switching process between the pressure holding and molding state and the material injection state.

[0006] In some embodiments, the cylinder body has a rodless chamber and a rod chamber, and the control oil circuit module includes a three-position four-way valve, the three-position four-way valve having a pressure port, an oil return port, a first interface, and a second interface. The first interface is connected to the rodless chamber, and the second interface is connected to the rod chamber. The pressure port is controllably connected to the pressure oil circuit, and the oil return port is connected to the oil return circuit. The three-position four-way valve has a left position, a middle position, and a right position. When in the left position, the pressure port is connected to the second interface, and the oil return port is connected to the first interface. When in the middle position, the pressure port is cut off from connection, and the first interface, the second interface, and the oil return port are connected. When in the right position, the pressure port is connected to the first interface, and the oil return port is connected to the second interface. During the closing process of the movable mold and the fixed mold, the three-position four-way valve is in the right position. During the opening process of the movable mold and the fixed mold, the three-position four-way valve is in the left position. During the switching process from the material injection state to the pressure holding and molding state, the three-position four-way valve is in the middle position.

[0007] In some embodiments, the interior of the first interface is connected to a throttling structure.

[0008] In some embodiments, a first one-way valve is connected in series on the oil circuit between the oil return port and the oil return oil circuit, and a conducting direction of the first one-way valve is from the oil return port to the oil return oil circuit.

[0009] In some embodiments, the oil circuit between the first interface and the rodless chamber is the first oil circuit, the oil circuit between the oil return port and the first one-way valve is the second oil circuit, and an overflow valve is connected in series between the first oil circuit and the second oil circuit.

[0010] In some embodiments, a one-way oil circuit and a pressure reducing oil circuit are connected in parallel between the second interface and the rod chamber, wherein a second one-way valve is connected in series to the one-way oil circuit, and the conduction direction of the second one-way valve is from the rod chamber to the second interface, and a pressure reducing valve is connected in series to the pressure reducing oil circuit, and the pressure reducing valve is a one-way pressure reducing valve, and the conduction direction of the pressure reducing valve is from the second interface to the rod chamber.

[0011] In some embodiments, an oil pressure sensor is provided on the oil circuit between the first interface and the rodless cavity.

[0012] In some embodiments, an electromagnetic two-way valve is connected in series on the oil circuit between the pressure port and the pressure oil circuit.

[0013] The present invention also provides a method for controlling the above-mentioned foam injection mold, comprising the following steps:

[0014] Controlling the piston rod of the mold-shifting oil cylinder to extend and drive the movable mold to move closer to the fixed mold to achieve mold clamping of the movable mold and the fixed mold until the movable mold is in the pressure-holding and shaping state; then controlling the piston rod of the mold-shifting oil cylinder to retract and drive the movable mold to move a preset distance away from the fixed mold so that the movable mold is in the material injection state; injecting foaming material into the mold cavity during the process of the movable mold switching from the pressure-holding and shaping state to the material injection state; and controlling the three-position four-way valve to be in the right position during the process of the movable mold clamping and switching from the pressure-holding and shaping state to the material injection state;

[0015] After the injection of the foaming material is completed, the piston rod of the mold-moving cylinder is controlled to extend again to drive the movable mold to switch to the pressure-holding and shaping state, and during this process, the three-position four-way valve is controlled to be in the middle position;

[0016] After the foaming material in the cavity is shaped, the piston rod of the mold-moving cylinder is controlled to retract again to drive the movable mold and the fixed mold to open, and the three-position four-way valve is synchronously controlled to be in the left position.

[0017] The present invention provides a foaming injection mold and a control method thereof, in which a sealing ring is arranged around the periphery of the cavity, and the sealing ring is configured to seal the parting surface gap of the cavity when the movable mold and the fixed mold are in the clamped state, thereby effectively preventing the foaming material from leaking from the parting surface gap when the movable mold is slightly opened, effectively eliminating material waste, ensuring the cleanliness of the production space, and at the same time ensuring the final quality of the injection molded product. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the foam injection mold in the embodiment of the present invention in the mold closing state (initial state). In this state, no foaming material is injected into the cavity, but the state of the movable mold is the same as that of the movable mold in the pressure holding state.

[0019] Figure 2 Schematic diagram of the foam injection mold in the embodiment of the present invention in the material injection state (that is, when the movable mold is slightly open);

[0020] Figure 3 Schematic diagram of the foam injection mold in the embodiment of the present invention in the pressure-holding and shaping state;

[0021] Figure 4 Schematic diagram of the principle of the control oil circuit module in an embodiment of the present invention (only showing the situation of driving one sealed oil cylinder).

[0022] The reference numerals indicate:

[0023] 1. Moving mold; 2. Fixed mold; 21. Injection port; 3. Sealing ring; 4. Sealing cylinder; 41. Sealing piston rod; 42. Cylinder body; 5. Control oil circuit module; 51. Three-position four-way valve; 511. Throttling structure; 52. First one-way valve; 53. Second one-way valve; 54. Pressure reducing valve; 55. Oil pressure sensor; 56. Overflow valve; 57. Solenoid two-way valve; 100. Cavity; P, pressure port; T, oil return port; A, first interface; B, second interface. DETAILED DESCRIPTION

[0024] See also Figures 1 to 4 As shown, according to an embodiment of the present invention, a foaming injection mold is provided, including a movable mold 1 and a fixed mold 2. The movable mold 1 can be driven by a mold-moving cylinder (not shown in the figure and not labeled) to move closer to or away from the fixed mold 2 to achieve mold closing and mold opening. When the movable mold 1 and the fixed mold 2 are closed, a cavity 100 is formed between the two. The shape of the aforementioned cavity 100 matches the specific injection molding object and is not particularly limited here. The foaming injection mold also includes a sealing ring 3 arranged around the periphery of the molding cavity 100. In a specific embodiment, the aforementioned sealing ring 3 is made of steel (specifically, it can be formed by stainless steel processing) and has a material injection state (such as ) when the movable mold 1 and the fixed mold 2 are closed. Figure 2 As shown) and the pressure holding state (as shown Figure 1 or Figure 3 As shown, the only difference between the two is that Figure 1 The initial state is shown in FIG. 1 , in which the foaming material is not injected into the cavity 100. Figure 3 In the middle, the foaming material is injected into the cavity 100 and is extruded again), wherein the distance between the movable mold 1 and the fixed mold 2 in the material injection state is greater than the distance between the movable mold 1 and the fixed mold 2 in the pressure holding and shaping state. In a specific embodiment, the distance in the material injection state is 2-3 mm greater than the distance in the pressure holding and shaping state, that is, the micro-opening distance of the movable mold 1 is 2-3 mm. Of course, according to actual production needs, the aforementioned micro-opening distance can be reasonably selected, but it can be understood that the thickness of the aforementioned sealing ring 3 (that is, the width in the micro-opening moving direction) should not be less than the corresponding micro-opening distance (that is, the parting surface gap described later), and the sealing ring 3 can block the parting surface gap of the cavity 100 in both the material injection state and the pressure holding and shaping state. It can be understood that in order to ensure reliable sealing of the aforementioned parting surface gap, the inner ring wall of the aforementioned sealing ring 3 should be able to form a sealing contact with the areas corresponding to the movable mold 1 and the fixed mold 2 and the cavity 100 respectively (specifically, this can be achieved by improving the surface smoothness).

[0025] In this technical solution, a sealing ring 3 is provided around the periphery of the cavity 100, and the sealing ring 3 is configured to seal the parting surface gap of the cavity 100 when the movable mold 1 and the fixed mold 2 are in the closed mold state, thereby effectively preventing the foaming material from leaking from the parting surface gap when the movable mold 1 is slightly opened, effectively eliminating material waste, ensuring the cleanliness of the production space, and ensuring the final quality of the injection molded product.

[0026] In some embodiments, the foaming injection mold also includes a plurality of sealing cylinders 4 with parallel oil circuits and a control oil circuit module 5 for controlling the synchronous extension and retraction of each sealing piston rod 41 of the sealing cylinder 4. The cylinder body 42 of each sealing cylinder 4 is assembled on the movable mold 1, and the free end of the sealing piston rod 41 of each sealing cylinder 4 is connected to the sealing ring 3. It can be understood that each sealing cylinder 4 should be connected to the sealing ring 3 at even intervals to ensure that each sealing cylinder 4 applies uniform force to the sealing ring 3, thereby ensuring the smooth movement of the position of the sealing ring 3. The control oil circuit module 5 is used to control the sealing piston rod 41 of each sealing cylinder 4 to apply force to the sealing ring 3 during the switching process between the pressure holding state and the material injection state to keep the sealing ring 3 sealed and in contact with the parting surface of the fixed mold 2.

[0027] In this technical solution, the sealing ring 3 is synchronously driven by multiple parallel sealing cylinders 4, which can ensure the smooth movement of the sealing ring 3 and prevent the sealing ring 3 from getting stuck with the movable mold 1 and / or the fixed mold 2 due to movement deviation.

[0028] See Figure 4 As shown, in some embodiments, the cylinder body 42 has a rodless cavity (in Figure 4 The left side of the orientation shown) and the rod cavity (in Figure 4The control oil circuit module 5 includes a three-position four-way valve 51, and the three-position four-way valve 51 has a pressure port P, an oil return port T, a first interface A, and a second interface B. The first interface A is connected to the rodless cavity, and the second interface B is connected to the rod cavity. The pressure port P is controllably connected to the pressure oil circuit (ultimately connected to the oil pump, not shown in the figure), and the oil return port T is connected to the oil return circuit (ultimately connected to the oil tank, not shown in the figure). The three-position four-way valve 51 has a left position, a middle position, and a right position. When in the left position, the pressure port P is connected to the second interface B, and the oil return port T is connected to the first interface A. When in the When in the middle position, the pressure port P is cut off from communication, and the first interface A, the second interface B and the return oil port T are connected. When in the right position, the pressure port P is connected to the first interface A, and the return oil port T is connected to the second interface B. In the process of closing the movable mold 1 and the fixed mold 2, the three-position four-way valve 51 is in the right position. In the process of opening the movable mold 1 and the fixed mold 2, the three-position four-way valve 51 is in the left position. In the process of switching from the material injection state to the pressure holding and molding state, the three-position four-way valve 51 is in the middle position. In a specific embodiment, the three-position four-way valve 51 adopts an electromagnetic servo valve.

[0029] In this technical solution, when the movable mold 1 is driven to switch from the material injection state to the pressure holding and molding state, the three-position four-way valve 51 can be controlled to be in the middle position. At this time, the extended length of the sealing piston rod 41 can be adaptively matched with the change in the spacing between the movable and fixed molds, preventing the individual adjustment of the telescopic length of the sealing piston rod 41 from causing the inaccurate position of the sealing ring 3 due to the deviation between the length adjustment of the sealing piston rod 41 and the telescopic length of the mold shifting cylinder, thereby causing sealing failure and material leakage. It should be particularly emphasized that in this technical solution, the middle position function of the three-position four-way valve 51 is used to maintain the relative position of the sealing piston rod 41 and the sealing ring 3 to the fixed mold 2 during the process of the movable mold 1 approaching the fixed mold 2, that is, the sealing ring 3 is always reliably sealed and connected to the fixed mold 2 and the movable mold 1.

[0030] In some embodiments, the first interface A is internally connected to a throttling structure 511 . The throttling structure 511 may specifically be a section of oil pipe with a smaller diameter located inside the first interface A.

[0031] In this technical solution, by setting a throttling structure 511 inside the first interface A, the hydraulic oil flowing out of the rodless cavity of the aforementioned cylinder body 42 can be throttled and controlled during the process of switching the movable mold 1 from the material injection state to the pressure holding and molding state when the three-position four-way valve 51 is in the middle position, thereby forming a back pressure in the rodless cavity. This can ensure that the retreat of the sealing piston rod 41 (that is, the retraction of the sealing piston rod 41 formed by following the movable mold 1 to approach the fixed mold 2) is smoother, and will not be too fast and cause the risk of damage to the cylinder body 42.

[0032] In some embodiments, a first one-way valve 52 is connected in series on the oil circuit between the oil return port T and the oil return circuit. The conducting direction of the first one-way valve 52 is from the oil return port T to the oil return circuit to prevent the return oil in other oil circuit systems of the equipment from entering the control oil circuit module 5 of the present invention.

[0033] In some embodiments, the oil circuit between the first interface A and the rodless chamber is the first oil circuit, and the oil circuit between the return oil port T and the first one-way valve 52 is the second oil circuit. An overflow valve 56 is connected in series between the first oil circuit and the second oil circuit. When the system pressure is higher than the set pressure, the pressure can be released in time to play a role of pressure protection and protect the entire oil circuit.

[0034] In some embodiments, a one-way oil circuit and a pressure reducing oil circuit are connected in parallel between the second interface B and the rod chamber, wherein a second one-way valve 53 is connected in series to the one-way oil circuit, and the conduction direction of the second one-way valve 53 is from the rod chamber to the second interface B, and a pressure reducing valve 54 is connected in series to the pressure reducing oil circuit, and the pressure reducing valve 54 is a one-way pressure reducing valve, and the conduction direction of the pressure reducing valve 54 is from the second interface B to the rod chamber.

[0035] In this technical solution, the aforementioned pressure reducing valve 54 can prevent the pressure of the hydraulic oil entering the rod chamber from being reduced when the three-position four-way valve 51 is in the left position, that is, when the sealing piston rod 41 is controlled to retract, and prevent excessive oil pressure from causing the sealing piston rod 41 to retract rapidly and damage the cylinder body 42.

[0036] In some embodiments, an oil pressure sensor 55 is provided on the oil circuit between the first interface A and the rodless cavity to detect the applied pressure of the hydraulic oil entering the rodless cavity. Once the pressure exceeds the set value, the system can alarm to ensure the safe operation of the equipment.

[0037] In some embodiments, an electromagnetic two-way valve 57 is connected in series on the oil circuit between the pressure port P and the pressure oil circuit. The pressure oil circuit is cut off or connected by the on-off switching of the electromagnetic two-way valve 57. In this way, when this function is not activated, the impact of the system oil circuit pressure on the downstream three-position four-way valve 51 is reduced, thereby playing a protective role.

[0038] In a preferred embodiment, the aforementioned three-position four-way valve 51, the first one-way valve 52, the second one-way valve 53, the pressure reducing valve 54, the overflow valve 56 and the electromagnetic two-way valve 57 are all integrated on the same valve block (not shown in the figure). It can be understood that corresponding oil flow channels are formed in the aforementioned valve block, so that the structure of the control oil circuit module 5 is compact and easy to assemble.

[0039] According to an embodiment of the present invention, there is also provided a method for controlling the above-mentioned foam injection mold, comprising the following steps:

[0040] The piston rod of the mold-moving oil cylinder is controlled to extend to drive the movable mold 1 to move close to the fixed mold 2 to achieve the mold closing between the movable mold 1 and the fixed mold 2 until the movable mold 1 is in the pressure-holding state (that is, the initial position, such as Figure 1 After the movable mold 1 is in the material injection state, the piston rod of the mold-shifting cylinder is controlled to retract and drive the movable mold 1 to move a preset distance (3 mm in a specific embodiment) away from the fixed mold 2, so that the movable mold 1 is in the material injection state, that is, the movable mold 1 is slightly opened. During the process of the movable mold 1 switching from the pressure-holding and shaping state to the material injection state, the foaming material (for example, including injection molding material and nitrogen for foaming) is injected into the mold cavity 100. During the process of the movable mold 1 being closed and switched from the pressure-holding and shaping state to the material injection state, the three-position four-way valve 51 is controlled to be in the right position to ensure that the sealing ring 3 always forms a contact seal with the fixed mold 2 during this process.

[0041] After the injection of the foaming material is completed, the piston rod of the mold-shifting cylinder is controlled to extend again to drive the movable mold 1 to switch to the pressure-holding state, and during this process, the three-position four-way valve 51 is controlled to be in the neutral position. During this process, due to the neutral function of the three-position four-way valve 51, the extended length of the sealing piston rod 41 will adaptively retract as the distance between the movable mold 1 and the fixed mold 2 decreases, that is, the retraction of the sealing piston rod 41 is completely synchronized with the approach process of the movable mold 1, effectively avoiding the occurrence of sealing failure caused by the asynchronous retraction of the sealing piston rod 41 and the extension and contraction of the piston rod of the mold-shifting cylinder;

[0042] After the foaming material in the cavity 100 is shaped, the piston rod of the mold-shifting cylinder is controlled to retract again to drive the movable mold 1 and the fixed mold 2 to open, and the three-position four-way valve 51 is synchronously controlled to be in the left position. At this time, the sealing piston rod 41 will be completely retracted, and the sealing ring 3 will be retracted synchronously, thereby exposing the molded injection molded part, which is conducive to the robot to remove the injection molded part from the cavity 100 position between the movable mold 1 and the fixed mold 2.

[0043] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0044] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention. The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art may make various improvements and variations without departing from the technical principles of the present invention, and such improvements and variations shall also be considered within the scope of protection of the present invention.

Claims

1. A foam injection mold, characterized in that: The invention comprises a movable mold (1) and a fixed mold (2), wherein the movable mold (1) can be moved closer to or farther from the fixed mold (2) under the drive of a mold-moving oil cylinder to realize mold closing and mold opening, and a mold cavity (100) is formed between the movable mold (1) and the fixed mold (2) when the mold is closed. The invention also comprises a sealing ring (3) arranged around the periphery of the molding cavity (100), and when the movable mold (1) and the fixed mold (2) are closed, there are a material injection state and a pressure holding and shaping state, wherein the distance between the movable mold (1) and the fixed mold (2) in the material injection state is greater than the distance between the movable mold (1) and the fixed mold (2) in the pressure holding and shaping state, and the sealing ring (3) can block the parting surface gap of the mold cavity (100) in both the material injection state and the pressure holding and shaping state.

2. The foaming injection mold according to claim 1, characterized in that: The invention also includes a plurality of sealing oil cylinders (4) with parallel oil circuits and a control oil circuit module (5) for controlling the synchronous extension and contraction of the sealing piston rods (41) of the sealing oil cylinders (4). The cylinder body (42) of each sealing oil cylinder (4) is assembled on the movable mold (1). The free end of the sealing piston rod (41) of each sealing oil cylinder (4) is connected to the sealing ring (3). The control oil circuit module (5) is used to control the sealing piston rod (41) of each sealing oil cylinder (4) to apply force to the sealing ring (3) during the switching process between the pressure holding and molding state and the material injection state to keep the sealing ring (3) in sealed contact with the parting surface of the fixed mold (2).

3. The foaming injection mold according to claim 2, characterized in that: The cylinder body (42) has a rodless chamber and a rod chamber in it. The control oil circuit module (5) includes a three-position four-way valve (51). The three-position four-way valve (51) has a pressure port (P), an oil return port (T), a first interface (A), and a second interface (B). The first interface (A) is connected to the rodless chamber, and the second interface (B) is connected to the rod chamber. The pressure port (P) is controllably connected to the pressure oil circuit, and the oil return port (T) is connected to the oil return oil circuit. The three-position four-way valve (51) has a left position, a middle position, and a right position. When in the left position, the pressure port (P) is connected to the second interface (B), and the oil return port (T) is connected to the first interface (A). When in the middle position, the pressure port (P) is disconnected, and the first interface (A), the second interface (B) and the oil return port (T) are connected. When in the right position, the pressure port (P) is connected to the first interface (A), and the oil return port (T) is connected to the second interface (B). In the process of closing the movable mold (1) and the fixed mold (2), the three-position four-way valve (51) is in the right position. In the process of opening the movable mold (1) and the fixed mold (2), the three-position four-way valve (51) is in the left position. In the process of switching from the material injection state to the pressure holding and shaping state, the three-position four-way valve (51) is in the middle position.

4. The foaming injection mold according to claim 3, characterized in that: The first interface (A) is internally connected to a throttling structure (511).

5. The foaming injection mold according to claim 3, characterized in that: A first one-way valve (52) is connected in series on the oil circuit between the oil return port (T) and the oil return oil circuit. The conducting direction of the first one-way valve (52) is from the oil return port (T) to the oil return oil circuit.

6. The foaming injection mold according to claim 5, characterized in that: The oil circuit between the first interface (A) and the rodless chamber is the first oil circuit, the oil circuit between the oil return port (T) and the first one-way valve (52) is the second oil circuit, and an overflow valve (56) is connected in series between the first oil circuit and the second oil circuit.

7. The foaming injection mold according to claim 3, characterized in that: A one-way oil circuit and a pressure reducing oil circuit are connected in parallel between the second interface (B) and the rod chamber, wherein a second one-way valve (53) is connected in series to the one-way oil circuit, and the conduction direction of the second one-way valve (53) is from the rod chamber to the second interface (B); a pressure reducing valve (54) is connected in series to the pressure reducing oil circuit, and the pressure reducing valve (54) is a one-way pressure reducing valve, and the conduction direction of the pressure reducing valve (54) is from the second interface (B) to the rod chamber.

8. The foaming injection mold according to claim 3, characterized in that: An oil pressure sensor (55) is provided on the oil circuit between the first interface (A) and the rodless chamber.

9. The foaming injection mold according to claim 3, characterized in that: An electromagnetic two-way valve (57) is connected in series to the oil circuit between the pressure port (P) and the pressure oil circuit.

10. A method for controlling a foam injection mold according to claim 3, characterized in that: The steps include: The piston rod of the mold-shifting oil cylinder is controlled to extend to drive the movable mold (1) to move closer to the fixed mold (2) to achieve the clamping of the movable mold (1) and the fixed mold (2) until the movable mold (1) is in the pressure-holding and shaping state, and then the piston rod of the mold-shifting oil cylinder is controlled to retract to drive the movable mold (1) to move away from the fixed mold (2) by a preset distance so that the movable mold (1) is in the material injection state, and the foaming material is injected into the mold cavity (100) during the process of the movable mold (1) switching from the pressure-holding and shaping state to the material injection state, and the three-position four-way valve (51) is controlled to be in the right position during the clamping of the movable mold (1) and the switching from the pressure-holding and shaping state to the material injection state; After the injection of the foaming material is completed, the piston rod of the mold-moving oil cylinder is controlled to extend again to drive the movable mold (1) to switch to the pressure-holding and shaping state, and in this process, the three-position four-way valve (51) is controlled to be in the middle position; After the foaming material in the mold cavity (100) is formed, the piston rod of the mold shifting cylinder is controlled to retract again to drive the movable mold (1) and the fixed mold (2) to open, and the three-position four-way valve (51) is synchronously controlled to be in the left position.

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