A drive mechanism for a valve pin of a hot runner system

Abstract

The application discloses a driving mechanism for a valve needle of a hot runner system, comprising a driver, a driving end of which is provided with a driving shaft, an axis of the driving shaft being a first axis; a casing is arranged on a side of the driver where the driving end is located, and the casing is internally provided with a mounting cavity; a displacement member is arranged in the mounting cavity and can be driven to move linearly along a second axis, the second axis being at an angle to the first axis, one end of the displacement member extending out of the casing and being provided with a connector for connecting the valve needle; a displacement driving member is coaxially arranged on the outer periphery of the displacement member and is in threaded cooperation with the displacement member, the displacement driving member can be rotated circumferentially about the second axis to drive the displacement member to move linearly along the second axis; a transmission mechanism is arranged in the mounting cavity, and the transmission mechanism comprises a first transmission mechanism arranged on the driving shaft and a second transmission mechanism arranged on the displacement driving member and in transmission cooperation with the first transmission mechanism. The application solves the problem of the prior art that the driving axis of the driving mechanism is coaxial with the displacement direction of the valve needle, which results in a large size of the casing of the driver and a small driving force.

Description

Technical Field

[0001] This invention belongs to the field of hot runner technology for plastic molds, and specifically relates to a valve needle drive mechanism for a hot runner system. Background Technology

[0002] Needle valve hot runner systems are widely used in injection molds, and the electric valve needle drive mode is an indispensable and important component of hot runners.

[0003] In the field of hot runner systems for plastic molds, servo motors or electric cylinders are increasingly used as drive mechanisms to move valve needles up and down. However, most current electric cylinders or motors used for valve needle driving are vertically mounted, meaning the axis of the drive mechanism is coaxial with the axis of the valve needle. For example, Chinese patent document CN210590259U, "A Drive Device for an Electric Valve Needle in a Hot Runner System," includes a servo motor and a hollow motor shaft within the servo motor. A valve needle with a head is axially inserted into the hollow motor shaft, and a transmission device is provided between the hollow motor shaft and the valve needle to drive the valve needle to move axially up and down when the hollow motor shaft rotates. The drive mechanism with the above structure has the following disadvantages: firstly, the thrust for driving the valve needle up and down is relatively small, resulting in insufficient power; secondly, it also leads to a larger axial dimension of the drive housing or gearbox, which in turn increases the mold platen thickness, significantly increasing mold costs and greatly raising both the manufacturing and operating costs.

[0004] Therefore, it is essential to redesign and develop a completely new valve needle drive mechanism for hot runner systems. Summary of the Invention

[0005] In view of at least one of the above-mentioned technical problems, the objective of this invention is to provide a valve needle drive mechanism for a hot runner system.

[0006] The technical solution of this invention is:

[0007] The present invention aims to provide a valve needle drive mechanism for a hot runner system. The drive mechanism includes a driver, a housing, a transmission mechanism and a valve needle displacement assembly disposed within the housing. The driver has a drive shaft at its drive end. The housing is disposed on the side where the driver's drive end is located and has a mounting cavity inside the housing. The transmission mechanism is disposed within the mounting cavity and includes a first transmission mechanism disposed on the drive shaft and a second transmission mechanism that drives and cooperates with the first transmission mechanism. The axis of the drive shaft is implemented as a first axis.

[0008] The valve needle displacement assembly includes a displacement element and a displacement driving element. The displacement element is disposed in the mounting cavity and can be driven to move linearly along a second axis. The second axis forms an angle with the first axis.

[0009] The displacement drive is coaxially disposed on the outer periphery of the displacement member and threadedly engaged with the displacement member. The second transmission mechanism is disposed on the displacement drive. The displacement drive can be driven by the driver to rotate circumferentially around the second axis to drive the displacement member to move linearly along the direction of the second axis.

[0010] Preferably, the first axis is perpendicular to the second axis.

[0011] Preferably, the driver is a motor.

[0012] Preferably, the displacement drive includes a ball screw nut and the displacement component includes a ball screw.

[0013] Preferably, the end of the displacement member extends out of the housing and is equipped with a connector for connecting the valve needle.

[0014] Preferably, the outer wall surface of the connector is a non-circular wall surface, and the inner wall surface of the through hole through which the displacement member passes in the housing is a non-circular wall surface that matches the outer wall surface of the connector.

[0015] Preferably, the displacement driving element includes:

[0016] A driving body is sleeved on the outer periphery of the displacement member, which is hollow inside and has an internal thread on its inner wall. The outer wall of the displacement member is provided with an external thread that matches the internal thread.

[0017] A limiting member is provided on the outer periphery of the driving body, and includes a first limiting sleeve and a second limiting sleeve that are coaxially connected and sleeved together along the second axis to limit the axial ends of the driving body respectively. The second transmission mechanism is fixedly connected to one of the first limiting sleeve or the second limiting sleeve.

[0018] The first limiting sleeve is sleeved on the outer side of one axial end of the driving body, and the inner wall of the first limiting sleeve and the outer wall of the driving body are provided with matching limiting structures. The second limiting sleeve is sleeved on the other axial end of the driving body and sleeved on one end of the first limiting sleeve. The second limiting sleeve extends along the second axis in a direction away from the first limiting sleeve.

[0019] The second limiting sleeve has a clearance through hole with its axis along the second axis, so that the end of the displacement member away from the end on which the connector is installed can move linearly.

[0020] Preferably, the limiting structure consists of a matching limiting protrusion and a limiting ring groove.

[0021] Preferably, the axial length of the first limiting sleeve is less than the axial length of the driving body;

[0022] The end of the first limiting sleeve that is furthest from the one that engages with the second limiting sleeve is level with one of the axial ends of the driving body;

[0023] Along the second axis, the inner wall of the second limiting sleeve is provided with two stepped limiting portions in sequence. The stepped limiting portion with a larger radial length is implemented as the first stepped limiting portion. The first stepped limiting portion corresponds to the axial end of the first limiting sleeve and its cross-section gradually narrows radially from top to bottom. The axial end of the first limiting sleeve is flush with the narrowest position of the first stepped limiting portion so that the axial end of the first limiting sleeve and the first stepped limiting portion have a first gap. The stepped limiting portion with a smaller radial length is implemented as the second stepped limiting portion. The second stepped limiting portion corresponds to the other axial end of the driving body and has a second gap.

[0024] Preferably, the diameter of the clearance through hole is larger than the outer diameter of the displacement member or the inner diameter of the drive body;

[0025] A limiting block is provided at the end of the displacement member away from the connector. The limiting block is sleeved on the end of the displacement member and fixed by fasteners. The outer wall of the limiting block slides in cooperation with the inner wall of the clearance through hole.

[0026] Preferably, the outer wall of the end of the first limiting sleeve away from the second limiting sleeve is recessed to form a first step, and a first bearing is supported between the first step and the inner wall of the housing;

[0027] The outer wall of the end of the second limiting sleeve away from the first limiting sleeve is recessed to form a second step, and a second bearing is supported between the second step and the inner wall of the housing.

[0028] Preferably, the outer wall of the first limiting sleeve on which the second transmission mechanism is mounted protrudes radially outward to form a third step, and the end of the second transmission mechanism away from the one that cooperates with the first transmission mechanism abuts against the third step.

[0029] Preferably, the first transmission mechanism and the second transmission mechanism are bevel gears; and / or

[0030] The housing includes a housing body and a cover plate that are fitted together along the second axis;

[0031] The shell body and the cover plate are distributed on both sides of the extension line of the first axis, and the cover plate is also provided with an adjustment component that can move along the second axis at the middle position.

[0032] Compared with the prior art, the advantages of the present invention are:

[0033] The valve needle drive mechanism of this invention for the hot runner system is not only more compact with fewer parts and better stability, but also significantly reduces the size of the actuator housing and the thickness of the mold plate, thus lowering manufacturing and operating costs. Furthermore, the use of a threaded engagement method for linear displacement enables precise linear positioning and provides a stronger driving force compared to existing coaxial drives. This solves the problems of existing technologies where the drive axis is coaxial with the valve needle's displacement direction, resulting in a large actuator housing, high mold and operating costs, and low driving force. Attached Figure Description

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0035] Figure 1 This is a cross-sectional structural diagram of the housing of the valve needle drive mechanism of the hot runner system according to an embodiment of the present invention.

[0036] Figure 2 This is a three-dimensional structural diagram of the valve needle drive mechanism of the hot runner system according to an embodiment of the present invention;

[0037] Figure 3 This is a cross-sectional schematic diagram of the limiting member of the valve needle drive mechanism in the hot runner system according to an embodiment of the present invention.

[0038] Figure 4 This is a cross-sectional schematic diagram of the drive body of the valve needle drive mechanism in an embodiment of the present invention.

[0039] Figure 5 This is a cross-sectional schematic diagram of the displacement component and the limiting block of the valve needle drive mechanism in an embodiment of the hot runner system of the present invention.

[0040] The components are as follows: 1. Driver; 11. Drive shaft; 2. Housing; 21. Housing body; 22. Cover plate; 23. Adjusting screw; 3. Displacement component; 31. Connecting part; 32. First connecting hole; 4. Displacement driving component; 41. Driving body; 411. Limiting ring groove; 412. Connecting groove; 42. Limiting component; 421. First limiting sleeve; 4211. First step; 4212. Third step; 4213. Limiting step; 4214. Second connecting hole; 4215. Groove; 422. Second limiting sleeve; 4221. Clearance through hole; 4222. First step limiting part; 4223. Second step limiting part; 4224. Second step; 5. Transmission mechanism; 51. First transmission mechanism; 52. Second transmission mechanism; 6. First bearing; 7. Second bearing; 8. Connector; 81. Pin; 9. Screw; 10. Limiting block; 101. Fastener. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0042] See Figures 1 to 5 An embodiment of the present invention provides a valve needle drive mechanism 1 for a hot runner system, comprising a driver 1, a housing 2, a displacement member 3, a displacement drive member 4, and a transmission mechanism 5. The driver 1 provides driving force to displace the displacement member 3, and the drive end of the driver 1 is as follows: Figure 1 The right end shown has a drive shaft 11, the axis of which is implemented as the first axis (i.e. Figure 1 (Middle horizontal dashed line), the driver 1 can be a servo motor or an electric cylinder, and in this embodiment of the invention, a motor is preferred. The housing 2 is located on the side where the driver 1 is driven, that is, as shown in the figure. Figure 1 On the right side of the drive end shown, the housing 2 is hollow, meaning that the housing 2 has a mounting cavity for mounting the displacement component 3, the displacement drive component 4, and the transmission mechanism 5. The displacement component 3 is located within the mounting cavity and can be driven along the second axis (e.g., Figure 1 The vertical dashed line shown moves in a straight line, with the second axis forming an angle with the first axis, ranging from 0° to 90°. In this embodiment of the invention, for example... Figure 1 As shown, the second axis is perpendicular to the first axis, meaning the angle between them is 90°, resulting in a simpler and more compact structural design. One end of the displacement component 3 extends out of the housing 2, specifically as shown... Figure 1The bottom of the housing 2 shown is fitted with a connector 8 for connecting the valve needle. The specific structure of the connector 8 is not described or limited; for example, it may have a T-shaped connecting groove 412 that matches the valve needle head. The displacement drive 4 is coaxially located on the outer periphery of the displacement member 3 and threadedly engaged with it. The displacement drive 4 can rotate circumferentially around the second axis to drive the displacement member 3 to move linearly along the second axis. Using a threaded connection, the rotation of the displacement drive 4 is converted into linear displacement of the displacement member 3, achieving high-precision displacement positioning with a compact structure and fewer components. Regarding the shape of the connector 8, because the displacement member 3 and the displacement drive 4 are threadedly engaged, when the displacement drive 4 rotates, the displacement member 3 also rotates, and the connector 8 will also rotate accordingly. However, this is not what we want; we only need the displacement member 3 to move linearly along the second axis. Therefore, preferably, in this invention, the connector 8 is designed as a non-circular shape, such as a square prism, that is, the outer wall surface of the connector 8 is a square surface. Correspondingly, the inner wall surface of the through hole through which the displacement member 3 passes in the housing 2 is also a matching non-circular shape, such as a square surface, that is, the through hole is a square hole. This design can prevent the displacement member 3 from rotating, that is, ensure that the displacement member 3 can only move linearly along the second axis. In an alternative embodiment, the outer wall surface of the displacement member 3 can also be other shapes, such as triangles, pentagons, or other polygons. Correspondingly, the inner wall surface of the through hole through which the displacement member 3 passes in the housing 2 is also a matching shape. The transmission mechanism 5 is located in the mounting cavity and includes a first transmission mechanism 515 located on the drive shaft 11 and a second transmission mechanism 525 located on the displacement drive member 4 and engaging with the first transmission mechanism 515. That is, the driving force of the driver 1 is transmitted to the displacement drive member 4 through the transmission mechanism 5, and then the displacement drive member 4 drives the displacement member 3 to move linearly along an axis different from the drive axis of the driver 1. Not only is the structure more compact with fewer parts, better stability, and simpler maintenance, but it also greatly reduces the size of the driver housing and the thickness of the mold template, thus reducing manufacturing and operating costs. At the same time, it uses a threaded engagement method to drive linear displacement, and through the anti-rotation structure design, the displacement component 3 can only move in a straight line and will not drive the connector 8 to rotate. This enables precise positioning of linear displacement and the driving force is more sufficient than that of the existing coaxial drive.

[0043] According to some preferred embodiments of the present invention, the valve needle drive assembly is a ball screw device. The displacement drive component 4 includes a ball screw nut and the displacement component 3 includes a ball screw. The structure is simple, capable of converting rotary motion into linear motion or torque into axial repetitive force, while also possessing high precision, reversibility, and high efficiency. Furthermore, it exhibits very low frictional resistance, requiring only a small torque for the driver 1 to start.

[0044] According to some preferred embodiments of the present invention, such as Figure 1 and Figures 3 to 5 As shown, the displacement driving component 4 includes a driving body 41 and a limiting component 42. (As indicated...) Figure 1 and Figure 4 As shown, the driving body 41 is a hollow cylindrical driving body with internal threads on its inner wall. The driving body 41 is sleeved on the outer periphery of the displacement member 3. The outer wall of the displacement member 3 has external threads that match the internal threads. That is, the driving body 41 is threadedly connected to the displacement member 3 through the internal threads on its inner wall and the external threads on its outer wall. The limiting member 42 is provided on the outer periphery of the driving body 41. Specifically, as shown... Figure 1 and Figure 3 As shown, the limiting member 42 is composed of two hollow cylindrical bodies, which are respectively implemented as a first limiting sleeve 421 and a second limiting sleeve 422. They are coaxially aligned vertically along the second axis and sleeved together to limit the axial ends of the driving body 41. The second transmission mechanism 525 is fixedly connected to either the first limiting sleeve 421 or the second limiting sleeve 422. That is to say, the limiting member 42 can only rotate circumferentially with the second transmission mechanism 525 and cannot rotate along the second axis. Figure 1 The vertical movement shown can be converted into linear movement of the internal displacement element 3 through rotation. The first limiting sleeve 421 is sleeved on one axial end of the driving body 41, that is, as shown... Figure 1 The lower end shown has a matching limiting structure on its outer side and inner wall, as well as on the outer wall of the driving body 41. The limiting structure achieves a fixed connection between the first limiting sleeve 421 and the driving body 41. The second limiting sleeve 422 is located at the other axial end of the driving body 41, i.e. Figure 1 The upper end shown is also the end of the first limiting sleeve 421, i.e. Figure 1 As shown, the upper end is sleeved and the second limiting sleeve 422 is oriented along the second axis in a direction away from the first limiting sleeve 421, that is, as Figure 1 The upward extension shown, through the design of the extension portion, provides guiding constraints for the linear movement of the displacement member 3. The second limiting sleeve 422 has a clearance through hole 4221 with its axis along the second axis direction, allowing the end of the displacement member 3 away from the end where the connector 8 is installed to move linearly. The design of the clearance through hole 4221 provides guidance while avoiding interference with the linear movement of the displacement member 3.

[0045] According to some preferred embodiments of the present invention, the limiting structure consists of a matching limiting protrusion and a limiting ring groove 411. For example, a limiting protrusion can be provided on the inner wall of the first limiting sleeve 421, and a corresponding limiting ring groove 411 can be formed on the outer wall of the driving body 41. As an alternative embodiment, a limiting ring groove 411 can also be formed on the inner wall of the first limiting sleeve 421, and a corresponding limiting protrusion can be provided on the outer wall of the driving body 41. In the embodiments of the present invention, such as Figure 3As shown, the first limiting sleeve 421 is hollow, and the hollow cavity is wider at the top and narrower at the bottom, so that the inner wall of the first limiting sleeve 421 is formed with a limiting step 4213. Figure 4 As shown, the outer wall of the driving body 41 is wider at the top and narrower at the bottom, and the outer wall is radially recessed inward at the junction of the wide and narrow parts to form a limiting annular groove 411. The step surface of the limiting step 4213 and the top surface of the limiting annular groove 411 contact each other to form a limit, thereby realizing the fixed connection between the first limiting sleeve 421 and the driving body 41.

[0046] According to some preferred embodiments of the present invention, such as Figure 1 and Figure 3 As shown, the axial length of the first limiting sleeve 421 is less than the axial length of the driving body 41. The end of the first limiting sleeve 421 furthest from the end that engages with the second limiting sleeve 422 is also... Figure 1 The lower end shown is flush with one of the axial ends of the driving component, i.e., the lower end. Two stepped limiting portions are sequentially provided on the inner wall of the second limiting sleeve 422 along the second axis direction, wherein the stepped limiting portion with the larger radial length is, as shown... Figure 1 and Figure 3 The lower step limiting part shown here is described as the first step 4211 limiting part. The first step 4211 limiting part corresponds to the axial end, i.e., the upper end, of the first limiting sleeve 421. The step limiting part with a smaller radial length is also as shown... Figure 1 and Figure 3 The upper step limiting portion shown here is described as the second step 4224 limiting portion 4223. The second step 4224 limiting portion 4223 corresponds to the other axial end of the driving body 41, i.e., the upper end, and has a second gap. Specifically, as shown... Figure 3 As shown, the cross-section of the first step 4211 limiting part is an inverted cone shape, that is, wider at the top and narrower at the bottom. The upper end face of the first limiting sleeve 421 does not directly abut against the axial end face of the first step 4211 limiting part, but has a first gap. The upper end face of the first limiting sleeve 421 is flush with the narrowest position of the first step 4211 limiting part, that is, the bottom surface of the inverted cone. By setting the first gap and the second gap, space can be provided for the movement of the first limiting sleeve 421 and the driving body 41, which can effectively protect the entire displacement driving component 4.

[0047] According to some preferred embodiments of the present invention, such as Figure 1 , Figure 3 and Figure 5 As shown, the diameter of the clearance through hole 4221 is larger than the outer diameter of the displacement member 3 or the inner diameter of the drive body 41, and the outer diameter of the displacement member 3 is the same as the inner diameter of the drive body 41. The end of the displacement member 3 furthest from the end where the connector 8 is mounted is... Figure 5The upper end is provided with a limiting block 10 that is sleeved and fixed to the end of the displacement member 3 by a fastener 101 such as a screw. The outer wall of the limiting block 10 slides with the inner wall of the clearance through hole 4221, that is, the limiting block 10 is in the shape of an inverted U. The bottom end of the limiting block 10 can abut against the upper end face of the driving body 41 to stop the displacement member 3 from continuing to move downward and limit the downward displacement stroke of the displacement member 3. The lower end of the displacement member 3 is provided with a connector 8. The size of the connector 8 itself is larger than the inner diameter of the driving body 41, which limits the upward displacement stroke of the displacement member 3.

[0048] According to some preferred embodiments of the present invention, such as Figure 1 and Figure 3 As shown, the outer wall of the lower end of the first limiting sleeve 421, away from the second limiting sleeve 422, is recessed to form a first step 4211. A first bearing 6 is supported between the first step 4211 and the inner wall of the housing 2. The outer wall of the upper end of the second limiting sleeve 422, away from the first limiting sleeve 421, is recessed to form a second step 4224. A second bearing 7 is supported between the second step 4224 and the inner wall of the housing 2. The first step 4211 and the second step 4224 facilitate the installation of the first bearing 6 and the second bearing 7. The first bearing 6 and the second bearing 7 provide support for the rotation of the limiting sleeves, pressing against the outer ends of the first limiting sleeve 421 and the second limiting sleeve 422 respectively, thus achieving a tightening effect. It should be noted that the first bearing 6 and the second bearing 7 are planar bearings, and their inner rings can rotate together with the first limiting sleeve 421 and the second limiting sleeve 422.

[0049] According to some preferred embodiments of the present invention, such as Figure 1 and Figure 3 As shown, the outer wall of the first limiting sleeve 421, where the second transmission mechanism 525 is mounted, protrudes radially outward to form a third step 4212. The end of the second transmission mechanism 525 furthest from the one cooperating with the first transmission mechanism 515 abuts against the third step 4212. The third step 4212 facilitates the installation and fixation of the second transmission mechanism 525. The second transmission mechanism 525 is fixed to the first limiting sleeve 421 by screws or other connecting parts. Specifically, as shown... Figure 3As shown, a radially penetrating second connecting hole 4214 for installing a connector such as a screw 9 is formed on the outer wall of the first limiting sleeve 421. Similarly, a radially penetrating connecting hole (not shown) is also formed on the outer wall of the second transmission mechanism 525 at the position corresponding to the second connecting hole 4214. The third step 4212 and the first step 4211 are vertically opposite each other, and the radial length of the step surface of the first step 4211 is greater than the radial length of the step surface of the third step 4212. For the first transmission mechanism 515, its installation method is the same as that of the second transmission mechanism 525, that is, a radially penetrating connecting hole (not shown) is also formed on the side wall of the first transmission mechanism 515, and a corresponding connecting hole (not shown) is formed on the drive shaft 11. The first transmission mechanism 515 and the drive shaft 11 are fixedly installed by a connector such as a screw 9 passing through the connecting hole.

[0050] According to some preferred embodiments of the present invention, such as Figure 1 and Figure 2 As shown, the housing 2 includes a housing body 21 and a cover plate 22 that are disposed vertically along the second axis. The housing body 21 and the cover plate 22 are distributed on both sides of the extension line of the first axis, i.e., as shown... Figure 1 As shown on the upper and lower sides, the shell body 21 is actually partially located on the upper side of the first axis and mostly on the lower side of the first axis. The cover plate 22 also has an adjustable component, such as an adjusting nut, that can move along the second axis. The lower end of the adjusting nut is close to and presses against the upper end face of the outer ring of the second bearing 7 to fix the second bearing 7 inside the housing 2, thus achieving effective cooperation between the first bearing 6, the second bearing 7, and the first and second limiting sleeves 421 and 422.

[0051] like Figure 3 As shown, an annular groove is also formed on the upper outer wall of the first limiting sleeve 421. This annular groove gradually approaches the axial direction of the first limiting sleeve 421 from top to bottom, thus limiting the lower end face of the second limiting sleeve 422. Figure 5 As shown, the displacement member 3 is a connecting part 31 with a small diameter section at the bottom. The connecting part 31 has a first connecting hole 32 in the direction that is horizontal and perpendicular to the second axis. The connector 8 is fixedly connected to the displacement member 3 by passing through the first connecting hole 32 through the pin 81.

[0052] The driving mechanism of this invention operates on the principle that the driver 1 rotates, transmitting power to the first transmission mechanism 515, which in turn drives the first transmission mechanism 515 to rotate. The rotation of the first transmission mechanism 515 drives the second transmission mechanism 525 to rotate. The second transmission mechanism 525 is fixed to the displacement driving member 4, which in turn drives the displacement driving member 4 to rotate. The driving body 41 is threadedly engaged with the displacement member 3. The through hole in the housing 2 through which the displacement member 3 passes is a square hole, and the outer wall of the connector 8 is also a square wall, thus forming a stop-rotation effect on the displacement member 3. The driving body 41 is fixed vertically by the first limiting sleeve 421 and the second limiting sleeve 422. The rotation of the driving body 41 will drive the displacement member 3 to move linearly up and down along the second axis, thereby driving the connector 8 at the lower end of the displacement member 3 to follow (due to the design of the stop-rotation structure, the connector 8 can only move linearly with the displacement member 3). A valve needle is installed on the connector 8, and the valve needle can only move linearly along the second axis. The drive mechanism of the present invention has a more compact structure, fewer parts, and better stability. It greatly reduces the size of the housing 2 of the driver 1 and also reduces the thickness of the mold template, thus reducing the cost and usage. At the same time, the threaded engagement method and the anti-rotation structure design ensure that the displacement component can only perform linear motion and not circumferential rotation. This enables precise positioning of linear displacement and provides a stronger driving force compared to existing coaxial drives.

[0053] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A valve needle drive mechanism for a hot runner system, the drive mechanism comprising a driver (1), a housing (2), a transmission mechanism (5) disposed within the housing (2), and a valve needle displacement assembly, wherein the driver (1) has a drive shaft (11) at its drive end, the housing (2) is disposed on the side where the drive end of the driver (1) is located and has a mounting cavity therein, the transmission mechanism (5) is disposed within the mounting cavity and comprises a first transmission mechanism (51) disposed on the drive shaft (11) and a second transmission mechanism (52) that drives and cooperates with the first transmission mechanism (51), characterized in that, The axis of the drive shaft (11) is implemented as the first axis; The valve needle displacement assembly includes a displacement member (3) and a displacement driving member (4). The displacement member (3) is disposed in the mounting cavity and can be driven to move linearly along the second axis. The second axis forms an angle with the first axis. The displacement drive (4) is coaxially disposed on the outer periphery of the displacement member (3) and threadedly engaged with the displacement member (3). The second transmission mechanism (52) is disposed on the displacement drive (4). The displacement drive (4) can be driven by the driver (1) to rotate circumferentially around the second axis to drive the displacement member (3) to make linear motion along the second axis. The end of the displacement member (3) extends out of the housing (2) and is equipped with a connector (8) for connecting the valve needle; The displacement driving element (4) includes: A driving body (41) is sleeved on the outer periphery of the displacement member (3), which is hollow inside and has an internal thread on its inner wall. The outer wall of the displacement member (3) is provided with an external thread that matches the internal thread. A limiting member (42) is provided on the outer periphery of the driving body (41), and includes a first limiting sleeve (421) and a second limiting sleeve (422) that are coaxially sleeved together along the second axis to limit the axial ends of the driving body (41) respectively. The second transmission mechanism (52) is fixedly connected to one of the first limiting sleeve (421) or the second limiting sleeve (422). The first limiting sleeve (421) is sleeved on the outer side of one axial end of the driving body (41), and the inner wall of the first limiting sleeve (421) and the outer wall of the driving body (41) are provided with matching limiting structures. The second limiting sleeve (422) is provided at the other axial end of the driving body (41) and sleeved on one end of the first limiting sleeve (421). The second limiting sleeve (422) extends along the second axis in a direction away from the first limiting sleeve (421). The second limiting sleeve (422) has an clearance through hole (4221) with its axis along the second axis direction, so that the end of the displacement member (3) away from the end on which the connector (8) is installed can move linearly.

2. The valve needle drive mechanism for the hot runner system according to claim 1, characterized in that, The first axis is perpendicular to the second axis.

3. The valve needle drive mechanism for the hot runner system according to claim 1, characterized in that, The driver (1) is a motor.

4. The valve needle drive mechanism for the hot runner system according to claim 1, characterized in that, The displacement drive (4) and displacement member (3) are ball screw devices, wherein the displacement drive (4) includes a ball screw nut and the displacement member (3) includes a ball screw.

5. The valve needle drive mechanism for a hot runner system according to claim 1, characterized in that, The outer wall of the connector (8) is a non-circular wall, and the inner wall of the through hole of the housing (2) through which the displacement member (3) passes is a non-circular wall that matches the outer wall of the connector (8).

6. The valve needle drive mechanism for the hot runner system according to claim 1, characterized in that, The limiting structure consists of a matching limiting protrusion and a limiting ring groove (411).

7. The valve needle drive mechanism for a hot runner system according to claim 1, characterized in that, The axial length of the first limiting sleeve (421) is less than the axial length of the driving body (41); The end of the first limiting sleeve (421) that is away from the one that is fitted with the second limiting sleeve (422) is flush with one of the axial ends of the driving body (41); Along the second axis, the inner wall of the second limiting sleeve (422) is provided with two stepped limiting portions in sequence. The stepped limiting portion with a larger radial length is implemented as the first stepped limiting portion (4222). The first stepped limiting portion (4222) corresponds to the axial end of the first limiting sleeve (421) and its cross-section gradually narrows radially from top to bottom. The axial end of the first limiting sleeve (421) is flush with the narrowest position of the first stepped limiting portion (4222) so that the axial end of the first limiting sleeve (421) and the first stepped limiting portion (4222) have a first gap. The stepped limiting portion with a smaller radial length is implemented as the second stepped limiting portion (4223). The second stepped limiting portion (4223) corresponds to the other axial end of the driving body (41) and has a second gap.

8. The valve needle drive mechanism for a hot runner system according to claim 1, characterized in that, The diameter of the clearance through hole (4221) is greater than the outer diameter of the displacement member (3) or the inner diameter of the drive body (41); A limiting block (10) is provided at the end of the displacement member (3) away from the connector (8) where it is installed. The limiting block (10) is sleeved on the end of the displacement member (3) and fixed by a fastener (101). The outer wall of the limiting block (10) slides in fit with the inner wall of the clearance through hole (4221).

9. The valve needle drive mechanism for a hot runner system according to claim 1, characterized in that, The outer wall of the first limiting sleeve (421) at the end away from the second limiting sleeve (422) is recessed to form a first step (4211), and a first bearing (6) is supported between the first step (4211) and the inner wall of the housing (2); The outer wall of the second limiting sleeve (422) at the end away from the first limiting sleeve (421) is recessed to form a second step (4224), and a second bearing (7) is supported between the second step (4224) and the inner wall of the housing (2).

10. The valve needle drive mechanism for a hot runner system according to claim 1 or 9, characterized in that, The outer wall of the first limiting sleeve (421) on which the second transmission mechanism (52) is mounted protrudes radially outward to form a third step (4212), and the end of the second transmission mechanism (52) away from cooperating with the first transmission mechanism (51) abuts against the third step (4212).

11. The valve needle drive mechanism for a hot runner system according to any one of claims 1 to 9, characterized in that, The first transmission mechanism (51) and the second transmission mechanism (52) are bevel gears; and / or The housing (2) includes a housing body (21) and a cover plate (22) that are fitted together along the second axis. The shell body (21) and the cover plate (22) are distributed on both sides of the extension line of the first axis, and the cover plate (22) is also provided with an adjustment member that can move along the second axis at the middle position.

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