Melt flow regulation system for injection nozzle

Abstract

The present invention belongs to the technical field of mold manufacturing, and particularly relates to a melt flow regulating system of an injection nozzle. The melt flow regulating system of the injection nozzle comprises a fluid supply circuit configured to selectively inject pressurized fluid from a reservoir to an actuator, the fluid supply circuit comprising a plurality of flow regulators placed in parallel to each other, the flow regulators being connected to a common regulating output and being equipped with a plurality of regulating inputs independent from each other to receive fluid from a flow channel. A fluid switching device is inserted between the second flow channel and the inputs of the N flow regulators, the device comprising a single control element equipped with N+K switchable and mutually exclusive operating configurations (K>1).

Description

Technical Field

[0001] The invention belongs to the technical field of mold manufacturing, and in particular relates to a melt flow regulating system for an injection nozzle. Background Art

[0002] In current injection molding machines, molten material is injected into the mold through one or more injection nozzles, and the opening and closing of the corresponding nozzles are regulated by one or more valve needles. For large or complex parts produced by multi-injection or sequential injection methods, it is crucial to control the position of the valve needle and thus the opening and closing of the nozzle to obtain high-quality injection-molded surface parts. In particular, it is crucial to control the flow rate of molten material and the injection pressure into the mold cavity. Currently, in order to manufacture high-quality products, valve needles are generally controlled by electric actuators because dynamic actuators are easy to adjust and control widely. However, the corresponding control equipment is complex and expensive, generally requiring an electronic control unit, related software, sensors and complex wiring, and professional operators are required to perform control operations.

[0003] Therefore, fluid-driven actuators are more popular with users due to their low manufacturing and operating costs. For example, European Patent Application Publication No. EP3490777 discloses a system for controlling a baffle in an injection molding system. The system includes: a hydraulic or pneumatic actuator cylinder coupled to the baffle, causing the baffle to slide between a nozzle-off position and a nozzle-maximum open position; a device for controlling the actuator cylinder, comprising: a first path fluidically connected to a first chamber of the actuator cylinder; a second path fluidically connected to a second chamber of the actuator cylinder; a third path for supplying fluid from a reservoir; and two monostable solenoid valves arranged to selectively establish fluid connection between the third path and either the first or second path. One of the monostable solenoid valves controls the possibility of blocking the opening of the baffle, while the other controls a slower or faster opening speed of the baffle. This system suffers from overly complex circuitry and difficult control. In particular, the operation of the two monostable solenoid valves must be coordinated to control the flow of fluid through each flow regulator. The system is complex, programming is challenging, and timely resetting of the valve needle is difficult. Summary of the Invention

[0004] The purpose of the present invention is to solve the above problems and provide a melt flow regulation system for an injection nozzle. The system is simple, easy to program and the valve needle can be reset in time under special circumstances.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is as follows:

[0006] A melt flow regulation system for an injection nozzle includes a nozzle provided with a valve needle, an actuator provided with a cavity and a piston, wherein the piston is arranged inside the cavity, and a fluid supply circuit including a liquid reservoir, a first flow channel, a second flow channel, a plurality of flow regulators, and at least one fluid switching device.

[0007] The piston moves linearly inside the cavity due to the thrust of the fluid, and the cavity is divided into a first chamber and a second chamber by the movement of the piston, the first chamber is connected to a first flow channel outside the actuator, and the second chamber is connected to a second flow channel outside the actuator;

[0008] The piston is connected to the valve needle and can repeatedly move the valve needle between a closed position and an open position;

[0009] The fluid supply circuit selectively injects pressurized fluid from the reservoir into the first flow passage to bring the valve needle to the open position, or injects pressurized fluid into the second flow passage to bring the valve needle to the closed position;

[0010] The plurality of flow regulators are placed in parallel and are equipped with independent regulating input ends for receiving fluid from the second flow channel; and connected to a common output end for returning the fluid taken from the second flow channel to the liquid reservoir; at least two flow regulators are provided,

[0011] The fluid switching device is arranged between the second flow channel and the inlets of the plurality of flow regulators, and comprises a single control element equipped with N switchable and mutually exclusive flow split configurations and K different dead point configurations:

[0012] In the N flow splitting configuration, the control element connects the second flow channel to one of the regulating inputs of the N flow regulators, allowing fluid to flow from the second flow channel to only one of the N flow regulators;

[0013] There are K dead points where the control element separates the fluid flow between the second flow channel and all N flow regulators, K ≥ 1.

[0014] The closed position of the valve needle is a position in which no molten material passes through the nozzle; the open position is a position in which molten material passes through the nozzle.

[0015] Each flow regulator has a regulated output, and all regulated outputs are brought together at a single common point, called the common output.

[0016] The N+K configuration provided by the fluid switching device of the present invention can provide sufficient freedom for programming the dynamic curve of the valve needle while keeping the circuit configuration simple.

[0017] Preferably, the fluid switching device includes N output control terminals and one input control terminal, the N output control terminals are respectively connected to the regulating input terminals of N flow regulators, and the regulating input terminals of the N flow regulators are all connected to the second flow channel.

[0018] By switching different flow splitting configurations, only one of the N output control terminals is fluidically connected to the input control terminal at a time.

[0019] In different configurations, the output control terminal connected to the corresponding flow regulator is also different.

[0020] In actual application, the construction mechanism of the control element and / or the fluid switching device determines N different, immutable and predefined configuration schemes to realize the connection between the second flow channel and the input control end of the fluid switching device and one of the N output control ends.

[0021] The N different immutable and predefined configurations correspond to N connection schemes between the input of the fluid switching device and the N output control terminals.

[0022] Preferably, the N connection graphs are different from each other.

[0023] More preferably, in the N different configurations, the output control terminal connected to the corresponding output control terminal is different from the output control terminal connected in other different configurations.

[0024] Preferably, the N+K different configurations in the fluid switching device are pre-set and immutable.

[0025] In the above-mentioned melt flow regulation system of the injection nozzle, the control element is set according to the sequence determined by the physical connection between the input control terminal and the output control terminal, and the second flow channel is only connected to one of the N output control terminals at a time.

[0026] To further simplify the system architecture, the control element is configured to connect the second flow channel to one of N output control terminals according to a predetermined sequence. This sequence can be internally predetermined, such as by a preset timetable to implement cyclic changes in the control element configuration, or externally predetermined, such as by physically connecting the N output control terminals to the N flow regulator input terminals. Because the timing of the output control terminals connected to the second flow channel is preferably predetermined internally by the fluid switching device and determined by changes to the fluid switching device, the dynamic curve of the valve needle can be programmed by selecting the output control terminals to which the flow regulator input terminals are to be connected.

[0027] In the above-mentioned melt flow regulation system of the injection nozzle, the control element is a movable component in the fluid switching device, which physically connects the second flow channel to any one of the N output control ends or any one of the K dead points through its displacement in a translational and / or rotational manner.

[0028] The control element can be moved to N+K different positions, which correspond to:

[0029] N connections, wherein the second flow channel is connected to one of the N output control terminals, each connection using a different output control terminal;

[0030] K connections, wherein the second flow channel is connected to one of the K dead points, each connection being a different dead point.

[0031] Preferably, the control element is configured to open or physically create the second flow channel by moving it, in particular, a communication channel between the input control end of the fluid switching device and any one of the N output control ends.

[0032] A dead point may be a blind leg or a control point in a fluid switching device that is not connected to a flow channel or outlet passage.

[0033] In order to further simplify the circuit, among the K dead points, K=1, and the fluid switching device is a solenoid valve with (N+1) positions, and the solenoid valve has a movable valve core.

[0034] In the above-mentioned melt flow control system of the injection nozzle, the valve core has (N+1) positions, including:

[0035] Rest position: the solenoid valve allows the fluid to flow from the second flow path only to the first flow regulator among the N flow regulators;

[0036] N-1 energizing positions: the solenoid valve allows the fluid to flow from the second flow path only to another flow regulator among the N flow regulators that is different from the first flow regulator, and each of the N-1 positions corresponds to a different flow regulator connected to the second flow path;

[0037] Second energized position: the solenoid valve isolates all N flow regulators from the second flow path;

[0038] All excitation positions can only be reached starting from the standstill position.

[0039] Furthermore, among the (N+1) positions of the valve core, N=2, and the valve core has only three positions, including:

[0040] In the rest position, the solenoid valve isolates the first flow regulator and the second flow regulator from the second flow path;

[0041] In the first energizing position, the solenoid valve allows the fluid to flow from the second flow path to the first flow regulator;

[0042] In the second energizing position, the solenoid valve allows the fluid to flow from the second flow passage to the second flow regulator;

[0043] The first excitation position and the second excitation position can only be reached starting from the idle position.

[0044] In the above-mentioned melt flow regulating system of the injection nozzle, the solenoid valve having (N+1) positions includes a one-way valve in the static position, and the one-way valve only allows the fluid to flow to the second flow channel.

[0045] In order to facilitate the programming of dynamic curves, set P(R i ) is the flow rate of the i-th flow regulator (1≤i≤N),

[0046] P(R1)<P(R2)<...<P(R N ) or P(R1)>P(R2)>...>P(R N ).

[0047] The present invention also provides a method for regulating a melt flow regulating system of an injection nozzle. The method utilizes the above-mentioned melt flow regulating system of the injection nozzle and comprises the following steps:

[0048] Connect the second flow channel to one of the N regulating input ports in sequence.

[0049] The second flow channel is fluidly isolated from all other N regulating inputs.

[0050] Only the state of one fluid control element is changed in the fluid switching device, in particular each of the above actions is achieved by a single switching of the control element, preferably by rotational and / or translational movement of the internal components of the fluid switching device, in particular the control element.

[0051] Preferably, the second flow channel is partially fluidically connected in the following order:

[0052] is connected to only one of the N regulating inputs and sends the fluid from the second flow channel to the regulating input;

[0053] or at a dead point to inhibit the fluid flow between the second flow passage and all N flow regulators.

[0054] Changing the state of only one fluid control element in the fluid switching device, such as by switching a single control element for each of the above actions, is preferably achieved by rotating and / or translating internal components of the fluid switching device, in particular the control element.

[0055] Preferably, the second flow channel is fluidically connected in the following order:

[0056] By a single switch of the control element, one of the N output control terminals is connected to one of the K dead points, then,

[0057] By a single switching of the control element, return from the dead point to the same output control terminal (starting point), then,

[0058] Connections can be made from the same output control terminal (starting point) to different output control terminals by a single switch of the control element.

[0059] Furthermore, by disconnecting the power supply of the fluid switching device and moving the fluid switching device to its static position, only the state of the fluid switching is changed to connect the second flow channel from one of the N output control terminals to the dead point.

[0060] Furthermore, only the state of the fluid switching is changed to change the state of the fluid control element:

[0061] By modifying or modulating a single electrical signal, preferably transmitted through a single control power line or a wired or wireless control channel; power is provided to a fluid switching device or an electrically isolated switching device.

[0062] Preferably, the second flow channel is connected to one of the K dead points of the same output control terminal (starting condition) by cutting off the power supply to the switching device.

[0063] The fluid may be, for example, a liquid, such as oil, or compressed air.

[0064] Compared with the existing technology, the advantages of the present invention are:

[0065] The N+K configuration provided by the fluid switching device of the present invention can provide sufficient freedom for programming the dynamic curve of the valve needle while keeping the circuit setting simple. The programming difficulty of the dynamic curve is low, which is more conducive to achieving smooth control of the valve needle. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 It is an embodiment of the melt flow regulating system of the injection nozzle of the present invention;

[0067] Figure 2 This is an embodiment of the melt flow regulation system of the injection nozzle of the present invention using a monostable solenoid valve;

[0068] Figure 3 The present invention is an embodiment in which the melt flow rate regulating system of the injection nozzle uses a solenoid valve equipped with a core shaft;

[0069] Figure 4It is another embodiment of the melt flow regulating system of the injection nozzle of the present invention;

[0070] Figure 5 This is another embodiment of the melt flow regulating system of the injection nozzle of the present invention. DETAILED DESCRIPTION

[0071] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0072] Example 1

[0073] like Figure 1 As shown, this embodiment provides a melt flow regulation system for an injection nozzle, hereinafter referred to as the MC1 system.

[0074] The MC1 system of this embodiment is used to drive an actuator 10, which is fixed to a support member such as a hot runner system, a manifold, a plate, or a mold (not shown). The actuator 10 moves a valve needle 12 in at least one injection nozzle (not shown) via a piston 14. The piston 14 moves linearly within a cavity 16 of the actuator 10. The cavity 16 is divided by the piston 14 into a first chamber 20 communicating with a first flow channel 22 and a second chamber 30 communicating with a second flow channel 32.

[0075] Combine Figure 1 As shown, the actuator 10 may be comprised of a single piston 14 .

[0076] In actual application, multiple pistons 14 can be stacked and connected to each other (not shown in the figure). The multiple pistons 14 can form multiple first chambers 20 and multiple second chambers that are respectively connected to the first flow channel 22 and the second flow channel 32. This variation effectively increases the thrust surface of the fluid without increasing the diameter of the piston 14 and the cylinder.

[0077] The first chamber 20 is usually isolated from the second chamber 30 . However, in some cases, the first chamber 20 and the second chamber 30 need to be connected to balance the pressures in the first flow channel 22 and the second flow channel 32 .

[0078] In practice, fluid, such as oil or air, can be introduced or drawn into the first chamber 20 or the second chamber 30 on either side of the piston 14 through the first flow channel 22 or the second flow channel 32, thereby enabling the piston 14 to move linearly in opposite directions, thereby moving the valve needle 12. The movement of the valve needle 12 determines whether the nozzle is opened or closed, controlling the flow of the melt into the mold cavity or preventing the flow of the melt.

[0079] The fluid comes from the reservoir 90. P represents the pressurization line from the reservoir 90 to the fluid, and T represents the fluid exhaust line.

[0080] The first solenoid valve 50 includes a movable second valve core 52 for reversing fluid flow in the first flow passage 22 and the second flow passage 32. Whether opening or closing, the flow direction determines the direction of movement of the piston 14 and, subsequently, the valve needle 12. In the static state, the first solenoid valve 50 remains in the first position, preventing fluid from flowing through the first flow passage 22 and the second flow passage 32, thereby keeping the piston 14 stationary.

[0081] The first solenoid valve 50 can then be switched to two different energized positions, allowing fluid to flow from the reservoir 90 to the actuator 10, as follows:

[0082] In the second excitation position, the fluid from the reservoir 90 can flow to the first chamber 20 through the first flow channel 22, and part of the fluid can flow out of the second chamber 30 to the second flow channel 32. At this time, the valve needle 12 moves to the open position.

[0083] In the third excitation position, the fluid from the reservoir 90 can flow along the second flow path 32 to the second chamber 30 , and part of the fluid can flow out of the first chamber 20 to the first flow path 22 , and the valve needle 12 moves toward the closed position.

[0084] There are two or more flow regulators R1, R2, ... R between the second flow channel 32 and the output of the first solenoid valve 50. N , N>=2, in this embodiment, N=4 is shown for the sake of convenience.

[0085] Flow regulator R1…R N are connected in parallel, with their respective regulating output terminals connected to the common output terminal 44 connected to the first solenoid valve 50, and their respective regulating input terminals I1...I N Isolate from each other.

[0086] From the regulating input I1…I N , flow regulator R1…R N The fluid may be delivered from the second flow passage 32 to the common output 44 and from there to the first solenoid valve 50 .

[0087] When the fluid flows in the reverse direction on the second flow channel 32, the flow regulators R1...R N Without intervention, the fluid flows through R1…R N The check valve 74 connected in parallel with the flow regulator flows, causing the piston 14 to close.

[0088] In the second flow channel 32 and the regulating input terminal I1 . . . I N A flow switch 100 is installed between the two terminals, which has an input control 110, N output control U1…U N and a switchable element 102. U1…U NThe output control is connected to the adjustment input terminals I1…I N , and the input control 110 is connected to the second flow channel 32 .

[0089] The specific structure of the switchable element 102 is as follows:

[0090] N split configurations connect the fluid of the input control 110 and the second flow channel 32 to U1...U N Output control, that is, only allowing the fluid to pass through I1...I from the second flow channel 32 N one of the,

[0091] At least one dead point, the fluid of the input control 110 and the second flow channel 32 is changed from all U1...U N Output control isolation, that is, preventing the fluid from flowing from the second flow channel 32 to all I1...I N enter.

[0092] The dead point of the switchable element 102 includes a dead point 104 for connecting the second flow channel 32 to the switching device 100 or disconnecting the additional output control terminal U from the fluid circuit of the first flow channel 22 and the second flow channel 32 .

[0093] The dead point of the switchable element 102 sets the flow regulators R1 ... R N The piston 14 is isolated from the second flow passage 32 and stops its travel.

[0094] Generally speaking, the flow switch 100 may include one or more dead points, for example, distributed at U1...U N Outputs to program different speed profiles with pauses in between. For example, Figure 1 In the embodiment of the present invention, the additional dead point 106 can replace the dead point 104 or exist simultaneously in the flow switch 100.

[0095] In the static state, the flow switch 100 is preferably set to a state that allows the fluid from the first solenoid valve 50 and the common output end 44 to be transmitted through the second flow channel 32. The fluid bypasses R1 ... R N Flow regulator.

[0096] At the start of the injection cycle, the switchable element 102 can remain in place and fluidically connect the second flow channel 32 to the R that is connected in the static state. i Flow regulator.

[0097] Alternatively, during the injection cycle, the switchable element 102 switches through one or more of its different configurations, each configuration allowing only one of the fluids from the second chamber 30 on the second flow channel 32 to pass through R1 ... R N Flow conditioner transmission.

[0098] When R1…R N When one of the flow regulators is connected to transmit fluid, it has a braking function similar to that provided by an internal combustion engine along a downhill path when changing the engaged gear. The flow rate of fluid out of the second chamber 30 and the velocity of the fluid entering the chamber 22 are restricted, thereby limiting the velocity of the piston 14.

[0099] Select R1…R N The flow regulator, in addition to allowing a uniform movement of the piston 14, also allows setting different movement speeds of the piston 14 during its stroke, since each R1 ... R N The flow regulator can make the next R1…R N Flow regulators reduce or increase the flow of fluid.

[0100] That is, let P(R i ) is the flow rate of the i-th flow regulator (1<=i<=N), then P(Ri) is equal to:

[0101] P(R1)<P(R2)<...<P(R N ) or P(R1)>P(R2)>...>P(R N ).

[0102] This relationship facilitates programming of valve needle 12 velocity profiles having strictly increasing or decreasing velocity ramps.

[0103] The cooperation between the flow switch 100 and the first solenoid valve 50 also ensures that downtime is avoided or reduced as much as possible when the valve needle 12 is driven.

[0104] For simplicity, the flow switch 100 may be configured to connect only the second flow channel 32 to R1 . . . R N The flow regulator or dead point 104 is as follows:

[0105] Sequentially switch the switchable element 102 from one U i Output control moves to the next U i+1 or U i-1 ,

[0106] Or, sequentially move the switchable element 102 from the U1 output control to the dead point 104,

[0107] Alternatively, the switchable element 102 is sequentially moved from the dead point 104 to the U1 output control.

[0108] Preferably, due to the presence of the flow switch 100, the following parts can be connected to the second flow channel 32 in sequence:

[0109] Only U1…U with strictly increasing or decreasing consecutive indices N Output control,

[0110] The dead point 104 after U1 output,

[0111] U1 output control after dead point 104.

[0112] See also Figure 1 The additional dead point 106 is shaded in FIG. 1 , and the additional dead point 106 can be connected to the second flow channel 32 in sequence:

[0113] Or is it to only have strictly increasing or decreasing consecutive indices U1…U N The outputs of the first subset of output controls are connected,

[0114] Or is it to only have strictly increasing or decreasing consecutive indices U1…U N The output of the second subset in the output control is connected, where the output of the first subset is different from the output of the second subset, but they together contain U1…U N All outputs of

[0115] Alternatively, the outputs belonging to the first subset and having a higher or lower flow rate are connected to the additional dead point 106, or vice versa.

[0116] Alternatively, the outputs belonging to the second subset and having a higher or lower flow rate are connected to the additional dead point 106, or vice versa.

[0117] While the above configuration may seem restrictive, it is actually advantageous in many applications. In these applications, a velocity profile needs to be programmed for the valve needle 12. This embodiment provides a valve needle with a strictly increasing or decreasing velocity ramp, and after the valve needle 12 stops, it restarts at the same or a different defined velocity. The MC1 system of this embodiment can be implemented without any additional or specialized control algorithms or complex circuitry.

[0118] The switchable element 102 may be a movable element in the flow switch 100 .

[0119] Example 2

[0120] like Figure 4 As shown, this embodiment provides another melt flow regulation system for an injection nozzle, hereinafter referred to as the MC2 system.

[0121] Between the second flow channel 32 and the output of the first solenoid valve 50, only two flow regulators, the first flow regulator 40 and the second flow regulator 42, are inserted. The first flow regulator 40 has a first input 46, and the second flow regulator 42 has a second input 48. The first flow regulator 40 and the second flow regulator 42 can refer to Figure 1The flow regulators R1, R2, the first flow regulator 40 and the second flow regulator 42 have the following relationship:

[0122] The flow rate of the second flow rate regulator 42 is less than the flow rate of the first flow rate regulator 40 .

[0123] In this embodiment, the flow switch 100 includes a second solenoid valve 60 having a movable second valve core 62, which switches the fluid in the second flow channel 32 to one of the first input 46 and the second input 48, or isolates the first flow regulator 40 and the second flow regulator 42 from the second flow channel 32.

[0124] In the rest position, the second solenoid valve 60 is maintained in the first position, allowing the fluid to flow to the second flow regulator 42 on the second flow passage 32 , and the piston 14 is at the first speed.

[0125] Starting from the first energized position: the second solenoid valve 60 can be electrically switched to two different energized positions, both of which can only be reached from the first position:

[0126] The second excitation position allows the fluid on the second flow channel 32 to flow to the first flow regulator 40, at which time the piston 14 is at the second speed, or

[0127] In the third excitation position, the first flow regulator 40 and the second flow regulator 42 are isolated from the second flow channel 32 , and the piston 14 is stationary.

[0128] During operation, the movement of the valve needle 12 can be dynamically adjusted by checking the positions of the first valve core 52 and the second valve core 62 .

[0129] Different dynamics of the valve needle 12 can be obtained by continuously switching the first solenoid valve 50 and the second solenoid valve 60, as shown in the table below.

[0130] Table 1 Relationship between the first solenoid valve, the second solenoid valve and the valve needle position

[0131]

[0132] In Table 1, the contents of the cells correspond to the spool positions shown in the drawing, with C representing the spool shown in the middle, B representing the spool shown at the bottom, and A representing the spool shown at the top, with the chronological order read from left to right. Note that each cycle begins and ends with the value [C, C], i.e. Figure 4 Rest position shown.

[0133] As can be seen from the table, in the MC2 system, in order to make the valve needle 12 move from a stationary state to a state moving at the highest speed, it is first necessary to move the valve needle 12 at a slower speed, which ensures that the translational movement of the valve needle 12 is smoother to reduce or avoid mechanical shock.

[0134] like Figure 3 As shown, this embodiment also provides another variation of the MC2 system.

[0135] The second solenoid valve 60 is replaced by a third solenoid valve 300 equipped with a third valve core 302. The third valve core 302 includes a rest position in which the first flow regulator 40, the second flow regulator 42 and the second flow channel 32 are fluidically isolated. The third solenoid valve 300 can then be electrically switched to two other different energizing positions, both of which can only be reached from the rest position:

[0136] The second excitation position only allows the fluid to flow from the second flow channel 32 to the second flow regulator 42.

[0137] Alternatively, the third excitation position only allows the fluid to flow from the second flow channel 32 to the first flow regulator 40 .

[0138] In this case, it can be seen that in order to switch the valve needle 12 from the slowest movement speed to the highest speed, the valve needle 12 must first stop, even if it is only for a short time, to ensure that the translation movement of the valve needle 12 is smoother and reduce or avoid mechanical shock.

[0139] Example 3

[0140] like Figure 5 As shown, this embodiment provides another melt flow regulation system for an injection nozzle, hereinafter referred to as the MC3 system.

[0141] The flow switch 100 includes a fourth solenoid valve 70 provided with a fourth valve core 72 and a one-way valve 74. The fourth valve core 72 is used to switch the fluid from the second flow channel 32 to one of the first input 46 and the second input 48, or to isolate the first flow regulator 40 and the second flow regulator 42 from the second flow channel 32.

[0142] In the static state, the fourth solenoid valve 70 remains in the first position, wherein the second flow passage 32 is in fluid communication with the first input 46 .

[0143] In the first energized position, the one-way valve 74 is disposed between the second flow passage 32 and the first input 46 , and the one-way valve 74 is included in the fourth spool 72 .

[0144] The fourth solenoid valve 70 can be electrically switched to two further different energizing positions, both of which can only be reached from the first energizing position:

[0145] The second excitation position only allows the fluid from the second flow channel 32 to flow to the first flow regulator 40.

[0146] Alternatively, the third excitation position only allows the fluid from the second flow channel 32 to flow to the second flow regulator 42 .

[0147] exist Figure 3 In the embodiment, if the third solenoid valve 300 is not energized, the valve needle 12 may remain in the blocked state because the fluid in the second flow passage 32 is not allowed to flow back toward the reservoir 90 .

[0148] In the MC3 system, this problem is solved because the one-way valve 74 ensures that the valve needle 12 is always allowed to close in the event of a power failure. The one-way valve 74 can be set to prevent fluid from flowing to the flow regulator but allow fluid to flow to the second flow channel 32.

[0149] This embodiment also provides another implementation method, such as Figure 2 As shown, the first solenoid valve 50 is of the monostable type which allows the valve needle 12 to close in the event of a power failure.

[0150] Generally, the permitted flow directions are indicated by arrows within the first and second valve spools 52 and 62 .

[0151] During operation, the movement of the valve needle 12 can be dynamically adjusted by checking the positions of the first valve core 52 and the second valve core 62 .

[0152] Combine Figure 2 As shown, the first solenoid valve 50 is replaced by a monostable solenoid valve 200, that is, its monostable valve core 202 has only two positions:

[0153] In the rest position or in the event of a power failure, pressurized fluid is delivered to the second flow passage 32 to close the valve needle 12.

[0154] In the energized position, pressurized fluid is delivered to the first flow passage 22 to open the valve needle 12 .

[0155] In actual application, the following adjustments are also applicable, including that at least one of the first solenoid valve 50, the second solenoid valve 60, and the fourth solenoid valve 70 is provided with an excitation coil and a return spring; and at least one of the solenoid valve 50, the second solenoid valve 60, and the fourth solenoid valve 70 is replaced by an equivalent flow deflection device.

[0156] Preferably, at least one of the MC1, MC2, and MC3 systems includes a flow switch 100 and a pump for delivering fluid from the reservoir 90. Using the aforementioned system, the dynamic curves of the valve needle shown in PCT / IB2019 / 053936, IT102017000037002, IT102016000080198, IT102016000055364, IT102015000008368, ITTO2014A001030, ITTO2014A001021, ITTO2014A000701, WO2012 / 074879A1, WO2012 / 087491A1, and WO2018 / 020177A1 can be obtained.

[0157] Although more relevant terms are used herein, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitations is contrary to the spirit of the present invention.

Claims

1. A melt flow control system for an injection nozzle, comprising a nozzle provided with a valve needle (12), an actuator (10) provided with a cavity (16) and a piston (14), wherein the piston (14) is arranged inside the cavity (16), and characterized in that: Also included is a fluid supply circuit, the fluid supply circuit including a liquid reservoir (90), a first flow channel (22), a second flow channel (32), N flow regulators and at least one fluid switching device, The piston (14) is linearly moved by fluid thrust inside the cavity (16), and the cavity (16) is divided into a first chamber (20) and a second chamber (30) by the movement of the piston (14), the first chamber (20) is connected to a first flow channel (22) outside the actuator (10), and the second chamber (30) is connected to a second flow channel (32) outside the actuator (10); The piston (14) is connected to the valve needle (12) and can repeatedly move the valve needle (12) between a closed position and an open position; The fluid supply circuit selectively injects pressurized fluid from the reservoir (90) into the first flow passage (22) to bring the valve needle (12) to the open position, or injects pressurized fluid into the second flow passage (32) to bring the valve needle (12) to the closed position; The N flow regulators are placed in parallel and are equipped with independent regulating input terminals for receiving fluid from the second flow channel (32); and are connected to a common output terminal (44) for returning the fluid taken from the second flow channel (32) to the liquid reservoir (90); at least two flow regulators are provided. The fluid switching device is arranged between the second flow channel (32) and the regulating input end of the N flow regulators, and the device comprises a single control element, which is equipped with N switchable and mutually exclusive diversion configurations and K different dead point configurations: In the N flow splitting configurations, the control element connects the second flow channel (32) to one of the regulating input ends of the N flow regulators, allowing the fluid to flow from the second flow channel (32) to only one of the N flow regulators; There are K dead points where the control element separates the fluid flow between the second flow channel (32) and all N flow regulators, K≥1.

2. The melt flow regulation system for an injection nozzle according to claim 1, characterized in that: The fluid switching device includes N output control terminals and one input control terminal, the N output control terminals are respectively connected to the regulating input terminals of N flow regulators, and the regulating input terminals of the N flow regulators are all connected to the second flow channel (32). By switching different flow splitting configurations, only one of the N output control terminals is fluidically connected to the input control terminal at a time. In different configurations, the output control terminal connected to the corresponding flow regulator is also different.

3. The melt flow regulation system for an injection nozzle according to claim 2, characterized in that: The (N+K) different configurations of the fluid switching device are pre-set and immutable.

4. The melt flow regulation system for an injection nozzle according to claim 1, characterized in that: The control element is arranged according to a sequence determined by the physical connection between the input control terminal and the output control terminal, and only the second flow channel is connected to one of the N output control terminals at a time.

5. The melt flow regulation system for an injection nozzle according to claim 2, characterized in that: The control element is a movable component in the fluid switching device, and the second flow channel (32) is physically connected to any one of the N output control terminals or any one of the K dead points by its displacement in a translational and / or rotational manner.

6. The melt flow regulation system for an injection nozzle according to claim 5, characterized in that: Among the K dead points, K=1, and the fluid switching device is a solenoid valve with (N+1) positions, and the solenoid valve has a movable valve core.

7. The melt flow regulation system for an injection nozzle according to claim 6, characterized in that: The valve core has (N+1) positions, including: Rest position: the solenoid valve allows the fluid to flow from the second flow channel (32) only to the first flow regulator among the N flow regulators; (N-1) energizing positions: the solenoid valve allows the fluid to flow from the second flow path (32) only to another flow regulator among the N flow regulators that is different from the first flow regulator, and each of the (N-1) positions corresponds to a different flow regulator connected to the second flow path; Isolation excitation position: the solenoid valve isolates all N flow regulators from the second flow channel (32); All excitation positions can only be reached starting from the standstill position.

8. The melt flow regulation system for an injection nozzle according to claim 6, characterized in that: The valve core has (N+1) positions, N=2, and the valve core has only three positions, including: In the rest position, the solenoid valve isolates the first flow regulator (40) and the second flow regulator (42) from the second flow channel (32); In a first energizing position, the solenoid valve allows fluid to flow from the second flow passage (32) to the first flow regulator (40); In the second energizing position, the solenoid valve allows the fluid to flow from the second flow passage (32) to the second flow regulator (42); The first excitation position and the second excitation position can only be reached starting from the idle position.

9. The melt flow regulation system for an injection nozzle according to claim 8, characterized in that: The solenoid valve with (N+1) positions includes a one-way valve (74) in a static position, and the one-way valve (74) only allows the fluid to flow to the second flow channel (32).

10. The melt flow regulating system for an injection nozzle according to any one of claims 1 to 8, characterized in that: P(R i ) is the flow rate of the i-th flow regulator, where 1≤i≤N, P(R1) < P(R2) < … < P(R N ) or P(R1) > P(R2) > … > P(R N ).

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