Valve needle driving device and hot runner system

Abstract

The invention belongs to the technical field of hot runner systems, and discloses a valve needle driving device and a hot runner system. The valve needle driving device comprises a motor, a transmission mechanism and a reversing mechanism. The transmission mechanism and the reversing mechanism are combined through motor driving, and the real-time opening degree of the valve needle can be accurately controlled according to the process requirement, so that melt glue is fully fused on a convergence interface, the weld mark defect is avoided, and the product quality is improved. When melt glue needs to be converged, the opening degree of the valve needle can be reduced to reduce the flow velocity of the melt glue. The kinetic energy of the melt glue at the joint of the cavities can be reduced by reducing the flow velocity, so that the probability of turbulent flow is reduced. And meanwhile, the flow speed is stable, so that the temperature distribution of the melt glue is more uniform, the problem of non-uniform shearing heat generation caused by high-speed flow is avoided, and the fusion condition of the melt glue on a convergence interface is further improved. The output shaft of the motor is perpendicular to the moving direction of the valve needle, so that the occupied space in the height direction is greatly reduced, the production cost is low, and the applicability is high.

Description

Technical Field

[0001] The present invention relates to the technical field of hot runner systems, and in particular to a valve needle drive device and a hot runner system. Background Art

[0002] In valve-type hot runner systems, controlling weld marks is a key factor affecting product quality. When multiple streams of molten plastic converge within the mold cavity, mismatched flow rates, pressure, or temperature can easily lead to weld marks at the convergence point, resulting in reduced product strength or cosmetic defects.

[0003] The valve needle, a core component controlling the flow of molten plastic, has a direct impact on weld mark formation. Existing technologies typically use pneumatic or hydraulic actuators to drive the valve needle. This mechanism operates by using air or hydraulic pressure to push a piston assembly, thereby driving the valve needle in axial reciprocating motion, opening and closing the flow path. To open the flow path, the valve needle is fully pushed open, allowing the molten plastic to rapidly inject into the mold cavity at maximum flow rate. To shut off the flow path, the valve needle is fully closed, instantly terminating the flow of molten plastic.

[0004] However, this "either on or off" control mode lacks the ability to adjust the melt flow rate, making it impossible to fine-tune flow parameters based on the melt confluence state. Specifically, when fully open, the melt flows into the cavity at high speed, easily causing turbulence or temperature unevenness at the confluence point; when fully closed, the melt flow is suddenly interrupted, resulting in an imbalance in the melt pressure in the confluence area. Both of these conditions result in insufficient fusion of the melt at the confluence interface, resulting in weld line defects and affecting product quality.

[0005] Furthermore, the cylinder of a traditional pneumatic or hydraulic actuator must be arranged along the valve needle's axis. The cylinder length must cover the full travel of the valve needle and allow for a safety margin. For multi-cavity molds or high-precision, miniaturized molds, the bulk of traditional pneumatic or hydraulic actuators can make installation impossible or require customized equipment, increasing production costs.

[0006] Therefore, the above problems need to be solved urgently. Summary of the Invention

[0007] The purpose of the present invention is to provide a valve needle drive device and a hot runner system to accurately control the real-time opening of the valve needle, thereby improving product quality, reducing production costs and improving applicability.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] A valve needle drive device includes a motor, a transmission mechanism, and a reversing mechanism, wherein:

[0010] The output shaft of the motor is perpendicular to the movement direction of the valve needle;

[0011] The transmission mechanism is in transmission connection with the output shaft, and the transmission mechanism is configured to convert the rotational motion of the output shaft into linear motion along the axis direction of the output shaft;

[0012] The valve needle is connected to the transmission mechanism through a reversing mechanism, and the reversing mechanism is configured to convert the linear motion output by the transmission mechanism along the axis direction of the output shaft into linear motion along the direction of movement of the valve needle, and maintain a constant transmission ratio during the motion conversion process to drive the valve needle to move.

[0013] Preferably, the transmission mechanism includes a screw rod, a slider and a reduction assembly, the screw rod and the slider are threadedly transmitted, and the output shaft is connected to the screw rod through the reduction assembly to drive the screw rod to rotate, thereby driving the slider to move along the screw rod.

[0014] Preferably, the screw rod is at least partially located within the radial projection area of ​​the motor, and the axis of the screw rod is consistent with the axis direction of the output shaft.

[0015] Preferably, the reduction assembly includes an input gear, a transmission gear, an intermediate gear and an output gear, the input gear is coaxially arranged on the output shaft, the transmission gear is meshed with the input gear for transmission, the transmission gear is coaxially arranged with the intermediate gear, the intermediate gear is meshed with the output gear for transmission, and the output gear is coaxially arranged on the screw rod.

[0016] Preferably, the slider includes a connecting part and an adjusting part, the connecting part is threadedly engaged with the screw rod, the adjusting part and the connecting part are slidably engaged along the axial direction of the screw rod and form an adjustment stroke, and the adjusting part can be fixed at any position in the adjustment stroke to adjust the structural length of the slider.

[0017] Preferably, the adjusting portion is screwed to the end portion of the connecting portion.

[0018] Preferably, the driving device further includes a cooling water channel surrounding the outer periphery of the motor, so that cooling water flows through the outer periphery of the motor to exchange heat with the motor.

[0019] Preferably, the reversing mechanism includes a swing arm and a fixed shaft, the swing arm is rotatably connected to the fixed shaft, the swing arm includes a first arm and a second arm extending outward from the center of rotation, the first arm and the second arm are perpendicular to each other, the first arm is hinged to the output end of the transmission mechanism, and the second arm is hinged to the valve needle.

[0020] Preferably, the first arm and the second arm are equal in length.

[0021] A hot runner system comprises a valve needle and the above-mentioned valve needle driving device, wherein the valve needle driving device is used to drive the valve needle to move.

[0022] Beneficial effects of the present invention:

[0023] The present invention uses a motor-driven, combined transmission mechanism and a reversing mechanism to precisely control the real-time opening of the valve needle according to process requirements, thereby allowing the molten glue to fully fuse at the confluence interface, avoiding the formation of weld mark defects and thus improving product quality. When the molten glue needs to merge, the valve needle opening can be reduced to reduce the flow rate of the molten glue. The reduction in flow rate can reduce the kinetic energy of the molten glue at the confluence of the cavity, thereby reducing the probability of turbulence. At the same time, a stable flow rate can make the temperature distribution of the molten glue more uniform, avoiding the problem of uneven shear heating caused by high-speed flow, and thus improving the fusion conditions of the molten glue at the confluence interface.

[0024] The present invention arranges the output shaft of the motor perpendicular to the movement direction of the valve needle, thereby greatly reducing the space occupied in the height direction, reducing the production cost, and increasing applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the motor and transmission mechanism provided by the present invention;

[0026] Figure 2 yes Figure 1 Enlarged view of point A in the middle;

[0027] Figure 3 It is a structural schematic diagram of the reversing mechanism provided by the present invention.

[0028] In the picture:

[0029] 100, valve needle;

[0030] 1. Motor; 11. Output shaft;

[0031] 2. Transmission mechanism; 21. Screw rod; 22. Slider; 221. Connecting part; 222. Adjusting part; 23. Speed ​​reduction assembly; 231. Input gear; 232. Transmission gear; 233. Intermediate gear; 234. Output gear;

[0032] 3. Reversing mechanism; 31. Swing arm; 311. First arm; 312. Second arm; 32. Fixed shaft. DETAILED DESCRIPTION

[0033] Before any embodiments of the present application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the foregoing drawings.

[0034] In this application, the terms "comprises," "includes," "has," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0035] In this application, the term "and / or" is a description of the association relationship between related objects, indicating that three relationships can exist. For example, a centrifugal vortex magnetic pump and / or a centrifugal vortex magnetic pump can represent three situations: the existence of a centrifugal vortex magnetic pump alone, the existence of a centrifugal vortex magnetic pump and a centrifugal vortex magnetic pump at the same time, and the existence of a centrifugal vortex magnetic pump alone. In addition, the character " / " in this application generally indicates that the related objects are in an "and / or" relationship.

[0036] In this application, the terms "connect," "combine," "couple," and "install" may refer to direct connection, combination, coupling, or installation, or indirect connection, combination, coupling, or installation. For example, a direct connection refers to two parts or components being connected together without an intermediary, and an indirect connection refers to two parts or components being connected to at least one intermediary, with the two parts or components being connected via the intermediary. Furthermore, "connect" and "couple" are not limited to physical or mechanical connections or couplings and may include electrical connections or couplings.

[0037] In this application, it will be understood by those skilled in the art that relative terms (e.g., "about," "approximately," "substantially," etc.) used in conjunction with quantities or conditions include the values ​​and have the meaning indicated by the context. For example, the relative terms include at least the degree of error associated with the measurement of a specific value, the tolerance caused by manufacturing, assembly, use, etc. associated with a specific value. Such terms should also be considered to disclose a range defined by the absolute values ​​of the two endpoints. Relative terms may refer to plus or minus a certain percentage (e.g., 1%, 5%, 10% or more) of the indicated value. Numerical values ​​that do not use relative terms should also be disclosed as specific values ​​with tolerances. In addition, "substantially" may refer to plus or minus a certain degree (e.g., 1 degree, 5 degrees, 10 degrees or more) on the basis of the indicated angle when expressing a relative angular position relationship (e.g., substantially parallel, substantially perpendicular).

[0038] In this application, it will be understood by those skilled in the art that the function performed by an assembly can be performed by one assembly, multiple assemblies, one part, or multiple parts. Similarly, the function performed by a part can also be performed by one part, one assembly, or a combination of multiple parts.

[0039] In the present application, the terms "upper", "lower", "left", "right", "front", "back" and other directional words are described based on the orientation and positional relationship shown in the accompanying drawings, and should not be understood as limiting the embodiments of the present application. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to the other element "upper" or "lower", but also be indirectly connected to the other element "upper" or "lower" through an intermediate element. It should also be understood that directional words such as upper side, lower side, left side, right side, front side, back side, etc. not only represent the positive orientation, but can also be understood as the lateral orientation. For example, below can include directly below, lower left, lower right, lower front and lower back, etc.

[0040] See also Figures 1 to 3 This embodiment provides a valve needle drive device, which includes a motor 1, a transmission mechanism 2, and a reversing mechanism 3. The output shaft 11 of the motor 1 is perpendicular to the movement direction of the valve needle 100. The transmission mechanism 2 is in transmission connection with the output shaft 11, and the transmission mechanism 2 is configured to convert the rotational motion of the output shaft 11 into linear motion along the axis of the output shaft 11. The valve needle 100 is in transmission connection with the transmission mechanism 2 through the reversing mechanism 3. The reversing mechanism 3 is configured to convert the linear motion output by the transmission mechanism 2 along the axis of the output shaft 11 into linear motion along the movement direction of the valve needle 100, and maintain a constant transmission ratio during the motion conversion process to drive the valve needle 100 to move.

[0041] In this arrangement, motor 1 serves as the power source, with its output shaft 11 positioned perpendicular to the direction of motion of valve needle 100. When motor 1 is operating, the rotational motion of output shaft 11 is converted by transmission mechanism 2 into linear motion along the axis of output shaft 11. This linear motion is then further converted by reversing mechanism 3 into linear motion along the axis of valve needle 100, thereby driving valve needle 100 in a reciprocating motion. During this process, the coordination between transmission mechanism 2 and reversing mechanism 3 ensures a linear correspondence between the rotation angle of motor 1 and the displacement of valve needle 100, enabling continuous adjustment of the valve needle 100's opening through precise control of motor 1.

[0042] It can be understood that by driving motor 1 in conjunction with transmission mechanism 2 and reversing mechanism 3, the real-time opening of valve needle 100 can be precisely controlled according to process requirements, thereby ensuring that the molten plastic fuses fully at the converging interface, avoiding weld mark defects and thus improving product quality. For example, when multiple streams of molten plastic merge, the output speed of motor 1 can be adjusted to maintain a specific opening of valve needle 100, allowing the molten plastic to be injected into the mold cavity at a moderate flow rate, avoiding the high-speed influx when fully open.

[0043] More importantly, because the valve needle 100's opening can be continuously adjusted, when the melts need to merge, the valve needle 100's opening can be lowered to reduce the melt flow rate. This reduced flow rate reduces the melt's kinetic energy at the cavity's confluence, thereby reducing the likelihood of turbulence. Furthermore, a steady flow rate ensures a more uniform melt temperature distribution, avoiding uneven shear heating caused by high-speed flow and improving the fusion conditions at the confluence interface.

[0044] It is also understandable that by arranging the output shaft 11 of the motor 1 perpendicular to the direction of movement of the valve needle 100, and combining this with actual application scenarios, the motor 1 is installed horizontally, and the rotational motion is converted into horizontal linear motion by the transmission mechanism 2, and then converted into vertical motion of the valve needle 100 by the reversing mechanism 3, thereby significantly reducing the space occupied in the height direction. Compared with traditional drive devices, the production cost is low and the applicability is high. For example, in a small precision mold, the drive device can be embedded in the side of the template without adding additional thickness to the template. This not only meets the equipment installation size restrictions, but also frees up more space for cavity layout and temperature control system layout, solving the space bottleneck of traditional technology from the structural design level.

[0045] It should be noted that in other embodiments, the motor 1 and the valve needle 100 can be directly connected only through the transmission mechanism 2, without using the reversing mechanism 3. In theory, the opening of the valve needle 100 can be adjusted by linear conversion of the rotational motion of the motor 1. However, since this only converts the rotational motion of the motor 1 into linear motion in the same direction, the travel of the valve needle 100 still occupies space in the height direction of the mold, which cannot meet the requirements of small precision molds.

[0046] Specifically, the transmission mechanism 2 includes a screw rod 21, a slider 22 and a reduction assembly 23. The screw rod 21 and the slider 22 are threaded, and the output shaft 11 is connected to the screw rod 21 through the reduction assembly 23 to drive the screw rod 21 to rotate, thereby driving the slider 22 to move along the screw rod 21. The threaded transmission structure of the screw rod 21 and the slider 22 can convert the rotational motion of the motor 1 into the linear motion of the slider 22. The transmission accuracy is high and can meet the requirements of fine-tuning the opening of the valve needle 100. In addition, the reduction assembly 23 amplifies the output torque of the motor 1 by reducing the speed ratio, so that the low-power motor 1 can drive the valve needle 100 to overcome the back pressure of the melt. The volume of the low-power motor is smaller than that of the high-power motor, which can further reduce the space occupied.

[0047] To further reduce space usage, the screw rod 21 is at least partially located within the radial projection area of ​​the motor 1, and the axis of the screw rod 21 is aligned with the axis of the output shaft 11. As can be seen from the above, by partially embedding the screw rod 21 within the radial projection area of ​​the motor 1 so that the axial lengths of the two partially overlap, space usage can be reduced.

[0048] Correspondingly, the reduction assembly 23 includes an input gear 231, a transmission gear 232, an intermediate gear 233, and an output gear 234. The input gear 231 is coaxially arranged on the output shaft 11, the transmission gear 232 meshes with the input gear 231 for transmission, the transmission gear 232 is coaxially arranged with the intermediate gear 233, the intermediate gear 233 meshes with the output gear 234 for transmission, and the output gear 234 is coaxially arranged on the lead screw 21. In this arrangement, the input gear 231 meshes with the transmission gear 232, and the transmission gear 232 then drives the output gear 234 through the intermediate gear 233, causing the lead screw 21 to rotate in a direction opposite to that of the output shaft 11 of the motor 1. As a result, the lead screw 21 and the motor 1 are arranged in opposite directions along the same axis, with their axial projections partially overlapping.

[0049] Generally speaking, if the slider 22 encounters an axial positioning deviation of the screw 21 during assembly, the initial position of the valve needle 100 will be offset, requiring rework and repair. To avoid this problem, in this embodiment, the slider 22 includes a connecting portion 221 and an adjusting portion 222. The connecting portion 221 is threadedly engaged with the screw 21, and the adjusting portion 222 is slidably engaged with the connecting portion 221 along the axial direction of the screw 21 to form an adjustment stroke, and the adjusting portion 222 can be fixed at any position in the adjustment stroke to adjust the structural length of the slider 22. As can be seen from the above, the adjustment stroke of the adjusting portion 222 can cover the common installation error range. For example, when the installation position of the screw 21 is 3mm backward, the adjusting portion 222 can be slid forward 3mm and locked to restore the total length of the slider 22 to the design value. In addition, after long-term use of the mold, the thread wear of the screw 21 will cause the stroke of the valve needle 100 to decay. Compared with replacing the screw 21, the above-mentioned adjustment structure can compensate for the error caused by the thread wear of the screw 21, thereby helping to reduce the cost of use.

[0050] Specifically, the adjustment portion 222 is threadedly connected to the end of the connecting portion 221. This threaded connection allows for precise quantification of linear displacement through the thread lead, thereby improving adjustment accuracy. Furthermore, the threaded coupling between the adjustment portion 222 and the connecting portion 221 is cost-effective and easy to operate.

[0051] To enhance the reliability of the drive unit, the drive unit also includes a cooling water channel surrounding the periphery of motor 1, allowing cooling water to flow through the periphery of motor 1 to exchange heat with motor 1, thereby preventing motor 1 overheating and causing drive unit failure. It should be noted that to achieve a continuous supply of cooling water, it also requires water supply components such as a deionized water tank and centrifugal pump; 222 temperature control and adjustment components such as a plate heat exchanger, a proportional control valve, and a temperature sensor; water quality assurance components such as a Y-type filter, a UV sterilizer, and a softening resin tank; pressure balancing components such as an expansion tank, a safety valve, a pressure gauge, and a flow meter; and intelligent control components such as a PLC controller. The centrifugal pump draws water from the deionized water tank through a filter and then feeds it into the cooling water channel surrounding motor 1. The temperature control unit adjusts the water temperature through a plate heat exchanger and a proportional control valve combined with temperature sensor feedback. The expansion tank and safety valve maintain system pressure stability. The flow meter and pressure gauge monitor operating parameters in real time. The PLC controller implements closed-loop control based on signals such as the temperature of motor 1 and issues an alarm and shutdown in the event of an abnormality. The specific structure of the above cooling water supply system is prior art and will not be described in detail.

[0052] In this embodiment, the reversing mechanism 3 includes a swing arm 31 and a fixed shaft 32. The swing arm 31 is rotatably connected to the fixed shaft 32. The swing arm 31 includes a first arm 311 and a second arm 312 extending outward from the center of rotation. The first arm 311 and the second arm 312 are perpendicular to each other. The first arm 311 is hinged to the output end of the transmission mechanism 2, and the second arm 312 is hinged to the valve needle 100. The first arm 311 and the second arm 312, which extend outward from the center of rotation of the swing arm 31 and are perpendicular to each other, are hinged to the output end of the transmission mechanism 2 and the valve needle 100, respectively. This achieves precise conversion of motion direction and efficient force transmission. With the rigid support of the perpendicular arm and the stable fulcrum of the fixed shaft 32, a compact and stable transmission path is formed during the conversion of the motion of the transmission mechanism 2 into linear reciprocating motion of the valve needle 100. This reduces the number of moving parts while improving assembly tolerance, making it suitable for layout in the confined space within a mold.

[0053] In this embodiment, the output end of the transmission mechanism 2 is the adjusting portion 222 of the slider 22, and the end of the first arm 311 away from the fixed shaft 32 is hinged to the adjusting portion 222 through a pin. Specifically, an axial hole is provided at the end of the adjusting portion 222, and a coaxial through hole is provided at the corresponding end of the first arm 311. The pin is passed through the two holes, and the pin and the axial hole are clearance-fitted, and a self-lubricating sleeve is embedded in the hole to form a sliding fit, which allows the two to rotate relative to each other around the pin and reduces wear to ensure smooth movement.

[0054] The end of the second arm 312, away from the fixed shaft 32, is transmission-connected to the valve needle 100 via a pin. Specifically, a valve needle connection block (not shown) is fixed to the end of the valve needle 100. The valve needle connection block has an axial hole, and the corresponding end of the second arm 312 has a coaxial through hole. The pin passes through the two holes and also forms a sliding fit with the self-lubricating bushing to achieve relative rotation between the second arm 312 and the valve needle connection block.

[0055] During transmission, the adjustment portion 222 of the slider 22 moves along the axis of the screw 21, driving the first arm 311 to rotate about the fixed axis 32 via the pin 33. After the swing arm 31 rotates synchronously as a whole, the second arm 312 pushes the valve needle connecting block via the pin 34, ultimately driving the valve needle 100 along its axis. This structure not only clarifies the hinged connection, but also avoids stress concentration in a rigid connection through the sliding fit of the bushing, ensuring precise transmission.

[0056] Furthermore, the lengths of the first arm 311 and the second arm 312 are equal, thereby forming equal-length levers, achieving a 1:1 force transmission ratio, avoiding transmission losses caused by force amplification or attenuation, and efficiently converting the output force of the transmission mechanism 2 into the driving force of the valve needle 100. In addition, the symmetrical arm structure forms a balanced torque during movement, suppressing the radial deflection of the swing arm 31 when rotating, and improving the straightness and reversing accuracy of the motion trajectory of the valve needle 100. In this embodiment, the first arm 311 and the second arm 312 of equal length and verticality form a 1:1 constant transmission ratio, and the input and output displacements are always equal and are not affected by the rotation angle, ensuring linear correspondence. Combined with the linear conversion of the transmission mechanism 2, a strict linear mapping of the rotation angle of the motor 1 and the displacement of the valve needle 100 is achieved, ensuring continuous and precise adjustment of the opening of the valve needle 100, making the melt flow stable and controllable, reducing defects, and improving product quality.

[0057] It should be noted that, in other embodiments, the reversing mechanism 3 may also adopt existing structures such as a bevel gear set, a crank slider 22 mechanism, etc., and this embodiment does not impose specific requirements and restrictions on this.

[0058] This embodiment further provides a hot runner system, which includes a valve needle 100 and the aforementioned valve needle drive device, wherein the valve needle drive device is used to drive the valve needle 100. It is understood that the hot runner system including the aforementioned valve needle drive device produces products of higher quality and lower production costs.

[0059] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. 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 claims of the present invention.

Claims

1. A valve needle drive device, characterized in that: It comprises a motor (1), a transmission mechanism (2) and a reversing mechanism (3), wherein: The output shaft (11) of the motor (1) is perpendicular to the movement direction of the valve needle (100); The transmission mechanism (2) is in transmission connection with the output shaft (11), and the transmission mechanism (2) is configured to convert the rotational motion of the output shaft (11) into linear motion along the axis direction of the output shaft (11); The valve needle (100) is connected to the transmission mechanism (2) through a reversing mechanism (3). The reversing mechanism (3) is configured to convert the linear motion output by the transmission mechanism (2) along the axial direction of the output shaft (11) into linear motion along the movement direction of the valve needle (100), and maintain a constant transmission ratio during the motion conversion process to drive the valve needle (100) to move.

2. A valve needle drive device according to claim 1, characterized in that: The transmission mechanism (2) comprises a screw rod (21), a slider (22) and a reduction assembly (23); the screw rod (21) and the slider (22) are threadedly driven; the output shaft (11) is connected to the screw rod (21) through the reduction assembly (23) to drive the screw rod (21) to rotate, thereby driving the slider (22) to move along the screw rod (21).

3. A valve needle drive device according to claim 2, characterized in that: The screw rod (21) is at least partially located within the radial projection area of ​​the motor (1), and the axis of the screw rod (21) is consistent with the axis direction of the output shaft (11).

4. A valve needle drive device according to claim 3, characterized in that: The deceleration assembly (23) comprises an input gear (231), a transmission gear (232), an intermediate gear (233) and an output gear (234); the input gear (231) is coaxially arranged on the output shaft (11); the transmission gear (232) and the input gear (231) are meshed and transmitted; the transmission gear (232) and the intermediate gear (233) are coaxially arranged; the intermediate gear (233) and the output gear (234) are meshed and transmitted; and the output gear (234) is coaxially arranged on the screw rod (21).

5. The valve needle drive device according to claim 2, characterized in that: The slider (22) includes a connecting portion (221) and an adjusting portion (222), wherein the connecting portion (221) is threadedly engaged with the screw rod (21), and the adjusting portion (222) and the connecting portion (221) are slidably engaged along the axial direction of the screw rod (21) to form an adjustment stroke, and the adjusting portion (222) can be fixed at any position in the adjustment stroke to adjust the structural length of the slider (22).

6. A valve needle drive device according to claim 5, characterized in that: The adjusting portion (222) is screwed to the end of the connecting portion (221).

7. The valve needle drive device according to claim 1, characterized in that: The driving device further comprises a cooling water channel surrounding the outer periphery of the motor (1), so that cooling water flows through the outer periphery of the motor (1) to perform heat exchange on the motor (1).

8. The valve needle drive device according to claim 1, characterized in that: The reversing mechanism (3) includes a swing arm (31) and a fixed shaft (32), wherein the swing arm (31) is rotatably connected to the fixed shaft (32), and the swing arm (31) includes a first arm (311) and a second arm (312) extending outward from a rotation center, wherein the first arm (311) and the second arm (312) are perpendicular to each other, the first arm (311) is hinged to the output end of the transmission mechanism (2), and the second arm (312) is hinged to the valve needle (100).

9. The valve needle drive device according to claim 8, characterized in that: The first arm (311) and the second arm (312) are equal in length.

10. A hot runner system, characterized in that: It comprises a valve needle (100) and a valve needle driving device according to any one of claims 1 to 9, wherein the valve needle driving device is used for driving the valve needle (100) to move.

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