Split rotary spool cut-off nozzle for integrated rack and pinion drive

Abstract

The utility model belongs to injection molding machine cut -off nozzle technical field, aiming at the existing traditional rotary valve type cut -off nozzle has the poor installation adaptation, the big volume of oil cylinder, the poor valve core sealing. The utility model provides a kind of split type rotary valve core cut -off nozzle of integrated gear rack driving device, including nozzle body, drive cylinder, transmission assembly and main valve core structure, eliminate over positioning by drive cylinder and rack connecting groove clearance fit, gear rack transmission assembly of initiative gear and rack composition;Valve core assembly hole installs main valve core and coaxial floating pin, and the upper and lower limit screws of two ends cooperate to form split type self-tightening seal, and set up glue discharge structure to avoid melt carbonization jam. The device compact structure, small space occupation, good sealing performance, high opening and closing precision, low wear, high degree of overall modularization, adapt to various injection molding machine installation and use, mainly used for nozzle melt cut -off control of injection molding equipment.

Description

Technical Field

[0001] This utility model relates to the field of flow-stopping nozzle technology for plastic injection molding machines, specifically a split rotary valve core flow-stopping nozzle with an integrated gear and rack drive device. Background Technology

[0002] After years of technological iteration, injection molding machine shut-off nozzles have evolved into various mature structural types, such as rotary valve type, needle valve type, and plunger type. All types of structures have stable and reliable application performance in actual injection molding production. Among them, the rotary valve type shut-off nozzle has become the nozzle type most frequently selected by mainstream injection molding equipment manufacturers as original equipment, due to its comprehensive advantages, and is widely used in the field of plastic molding and processing.

[0003] There are prior patents documenting conventional rotary valve-type shut-off nozzles, such as the traditional structure disclosed in Chinese Patent CN102666061A and European Patent EP0494304A1. The overall construction principle of this type of rotary valve nozzle is simple. It can complete the valve core rotation opening and closing action by relying on an external drive component in conjunction with a connecting rod and lever transmission. It is a classic design scheme commonly used in mass-produced models at present.

[0004] However, existing traditional rotary valve-type shut-off nozzles still have the following application shortcomings: (1) The product installation and adaptation constraints are complicated. The equipment installation specifications of various injection molding machine manufacturers are not uniform and the size standards are significantly different, resulting in high cost of nozzle whole machine matching and modification. (2) Traditional structure is equipped with an external oil cylinder as the driving component. The driving mechanism adopts an external lever transmission layout. The distance between the lever and the valve core is large. The valve core needs to rely on the driving mechanism to provide an ultra-long working stroke for opening and closing. This forces the driving device to be arranged externally at the rear, resulting in a large space occupied by the whole machine and a bulky appearance. (3) The traditional valve core adopts a straight-through plunger fixed sealing structure, which results in large melt leakage and insufficient sealing reliability under high pressure injection molding and material storage back pressure conditions. (4) Over-positioning is prone to occur when the piston rod of the drive cylinder is assembled with the rack, causing transmission jamming and seizure faults; (5) When the rack is disassembled or assembled from the cylinder, it is easy to slip out of the engagement position and disengage, which requires reassembly; (6) The plastic melt trapped in the valve core gap is prone to yellowing, carbonization and clumping when left at high temperature for a long time, which can then jam the main valve core.

[0005] It is evident that there is a need to provide a split rotary valve core throttling nozzle with an integrated gear and rack drive device to improve the traditional external lever transmission structure and straight-through plunger fixed sealing structure, and to solve the problems mentioned in the background technology, such as high model adaptation cost, large external drive volume, insufficient self-tightening sealing performance, assembly over-positioning jamming, rack disengagement, and melt carbonization jamming. Utility Model Content

[0006] The purpose of this invention is to provide a split rotary valve core shut-off nozzle with an integrated gear and rack drive device to solve the problems mentioned in the background art.

[0007] To solve the above-mentioned technical problems, this utility model provides the following technical solution: a split rotary valve core flow-stopping nozzle with an integrated gear and rack drive device, comprising a nozzle body, a transmission assembly, a drive cylinder, a coupling, and screws, characterized in that: the nozzle body is generally cylindrical, wrapped with a heating coil, and the nozzle body axis is provided with a flow channel that runs through the left and right sides; the nozzle body has a valve core assembly hole perpendicular to the flow channel in the middle for installing the main valve core, and one end of the main valve core extends out as a connecting rod smaller than the diameter of the main valve core for manipulating the rotation of the main valve core; a floating pin is installed at the other end of the main valve core, and an upper limit screw is screwed into the valve core assembly hole near the floating pin and a lower limit screw is screwed into the valve core assembly hole near the connecting rod; The transmission assembly includes a gearbox, and a drive gear is provided inside the gearbox. A gear shaft is connected above the drive gear, and a rack meshes with one side of the gear. A connecting groove is provided at one end of the rack. A piston rod is connected to the output end of the drive cylinder, and a protrusion is provided at one end of the piston rod. The protrusion is fitted into the connecting groove with a clearance fit. The drive cylinder is floatingly connected to the rack.

[0008] Preferably, the upper limit screw is provided with a discharge hole for discharging plastic stored in the upper gap.

[0009] Preferably, the upper end of the gearbox has two symmetrically arranged mounting brackets integrally formed, and the two mounting brackets precisely fix the gearbox module to the preset points on the outer wall of the nozzle body.

[0010] Preferably, the gearbox has symmetrically arranged assembly through holes on its upper and lower end faces, and a lower bearing cover and an upper bearing cover are respectively installed in the assembly through holes. Bearings are nested in the lower bearing cover and the upper bearing cover, and the gear shaft passes through the bearing to achieve axial and radial bidirectional limiting support.

[0011] Preferably, a wear-resistant block is installed on the back of the rack, and the wear-resistant block is locked and fixed to the inner wall of the gearbox by means of a wear-resistant block cover.

[0012] Preferably, the wear-resistant block has a limiting groove, and the outer side of the rack is integrally formed with a protrusion. The protrusion and the limiting groove cooperate with the locking screw on the wear-resistant block cover to limit the rack to slide within the stroke range and prevent the rack from coming out.

[0013] Preferably, the end face of the drive gear is engraved with an alignment mark to indicate the nozzle status, and an observation window is provided on the side wall of the gearbox corresponding to the position of the drive gear to observe the opening and closing status of the main valve core.

[0014] Preferably, one end of the nozzle body is connected to an adapter for connecting to the injection molding machine's material tube, and the adapter and the nozzle body are connected by a flange, with multiple sets of flange bolts evenly arranged around the flange for locking and fixing.

[0015] Preferably, the coupling is arranged between the nozzle body and the transmission assembly as a power transfer component between the main valve core and the gear shaft, and the bottom and sides of the gearbox are locked and fixed by stainless steel anti-loosening screws.

[0016] Preferably, the length of the main valve core is 0.05 to 0.2 mm shorter than the length of the valve core assembly hole, so that the main valve core 6 and the valve core assembly hole have an axial clearance of 0.05 to 0.2 mm, and the main valve core can complete the circumferential rotation without jamming in the valve core assembly hole.

[0017] Preferably, the protrusion is a cylindrical boss integrally formed at the end of the piston rod, and the connecting groove is a U-shaped groove opened at the end of the rack.

[0018] Compared with the prior art, the beneficial effects achieved by this utility model are: First, this utility model abandons the traditional external lever + single-point fulcrum hydraulic cylinder drive structure, and adopts a drive cylinder combined with rack and pinion and gear shaft to form an internal gear rack transmission structure. The entire transmission assembly is directly fixed on the outer wall of the nozzle body after being integrated by the gearbox. There is no need to extend a long lever and a rear external drive component on the outside of the valve core, which greatly reduces the space occupied by the overall nozzle installation, optimizes the overall size of the machine, reduces the adaptation and modification cost caused by non-standard sizes of different models, and improves the universal assembly performance of the nozzle across models.

[0019] Secondly, this utility model uses a main valve core combined with floating pins, upper and lower limit screws to form a pressure self-tightening sealing structure. It utilizes the melt cavity pressure under two working conditions: high injection pressure and back pressure storage, to make the floating pins and main valve core adaptively fit the limit screws to form an end face seal. Unlike the conventional straight-through plunger fixed sealing structure, it uses the pressure of the medium itself to achieve a split plunger self-tightening seal, which significantly reduces melt leakage under high-pressure injection and back pressure storage conditions and improves nozzle sealing reliability.

[0020] Third, this utility model eliminates the hidden danger of over-positioning of the piston rod and rack by floating assembly of the piston rod protrusion and the rack connecting groove, and avoids jamming failure caused by assembly tolerance. The rack is limited by the wear-resistant block and the protrusion to reliably constrain the rack movement range and prevent the rack from falling out. At the same time, the wear-resistant block can reduce the reciprocating sliding wear of the rack and extend the service life of the transmission mechanism.

[0021] Fourth, in this utility model, the drive gear adopts a non-full-circle tooth structure, and the number of teeth of the rack and the drive gear are matched and the tooth position reference is unified, which ensures that the valve core rotation stroke is accurate and consistent every time it is opened and closed, and improves the on-off control accuracy of the nozzle. The gearbox is an independent modular assembly unit, which facilitates standardized mass production of parts and disassembly and maintenance. The drive gear marking, together with the observation window of the box, allows for intuitive judgment of the valve core opening and closing status without disassembling the machine, making equipment debugging and fault diagnosis convenient.

[0022] Fifth, the upper limit screw in this utility model has a special discharge hole, which automatically and slowly discharges the residual material stuck in the valve core gap by relying on the periodic pressure change of the injection molding. This effectively avoids the failure of the melt being carbonized and clumped together and stuck in the main valve core due to long-term heat retention. Under the overpressure state of the inner cavity, the reverse pressure of the medium can limit the irregular free rotation of the valve core, avoid abnormal high-speed wear of the valve core and the seal, and extend the overall service life of the nozzle. Attached Figure Description

[0023] Figure 1 This is the overall outline drawing of the present utility model; Figure 2 This is an exploded view of the present invention; Figure 3 This is an assembly drawing of the present utility model; Figure 4 This is a diagram showing the nozzle valve core of this utility model in the closed state; Figure 5 This is a three-dimensional sectional view of the gearbox of this utility model; Figure 6 This is a structural diagram of the drive cylinder of this utility model; Figure 7 This is an exploded view showing the connection between the rack and the piston rod of this utility model; Figure 8 This is a schematic diagram showing the connection between the rack and the piston rod of this utility model; Figure 9 This is a structural diagram of the gear shaft of this utility model; Figure 10 This is a schematic diagram of the window opening in the gearbox of this utility model.

[0024] The components are as follows: 1. Adapter head; 2. Flange; 3. Nozzle body; 4. Upper limit screw; 5. Floating pin; 6. Main valve core; 7. Lower limit screw; 8. Flange screw; 9. Coupling; 10. Drive cylinder; 11. Screw; 12. Heating coil; 13. Transmission assembly; 1301. Gearbox; 1302. Gear shaft; 1303. Bearing; 1304. Lower bearing cover; 1305. Upper bearing cover; 1306. Wear-resistant block cover; 1307. Wear-resistant block; 1308. Rack; 1309. Protrusion; 1310. Drive gear; 14. Connecting groove; 15. Protrusion. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] Please see Figures 1 to 10 A split rotary valve core shut-off nozzle with integrated gear and rack drive device includes a nozzle body 3, a transmission assembly 13, a drive cylinder 10, a coupling 9, and screws 11. The nozzle body 3 is generally cylindrical and wrapped with a heating coil 12. A flow channel is provided through the left and right sides along the axis of the nozzle body 3. A valve core assembly hole perpendicular to the flow channel is provided in the middle of the nozzle body 3 for installing the main valve core 6. A connecting rod with a diameter smaller than that of the main valve core 6 extends from one end of the main valve core 6 to operate the main valve core 6 to rotate. A floating pin 5 is installed at the other end of the main valve core 6. An upper limit screw 4 is screwed into the valve core assembly hole near the floating pin 5 and a lower limit screw 7 is screwed into the valve core assembly hole near the connecting rod. The transmission assembly 13 includes a gearbox 1301, and a drive gear 1310 is provided inside the gearbox 1301. A gear shaft 1302 is connected above the drive gear 1310, and a rack 1308 meshes with one side of the gear. A connecting groove 14 is provided at one end of the rack 1308, and a piston rod is connected to the output end of the drive cylinder 10. A protrusion 15 is provided at one end of the piston rod, and the protrusion 15 is fitted into the connecting groove 14 with clearance. The drive cylinder 10 and the rack 1308 are floatingly connected.

[0027] Through the above technical solution, the main body of the equipment uses the nozzle body 3 as the supporting base. The nozzle body 3 is made of aluminum alloy casting, which is lightweight, structurally rigid, and not easily deformed. The heating ring 12 fitted on the outside of the nozzle body 3 is a ceramic heating ring, which has good heating uniformity and stable temperature rise, and can keep the plastic melt in the nozzle body 3 at a constant temperature, effectively avoiding the problems of melt cooling and solidification and poor fluidity. The nozzle body 3 has a melt flow channel through its axis, which serves as a plastic melt conveying channel. A valve core assembly hole is vertically opened in the middle to provide a precise installation position for the main valve core 6. The power transmission of the whole machine adopts an independent transmission component 13. The drive cylinder 10 can be either a pneumatic cylinder or a hydraulic cylinder to adapt to the power requirements of different injection molding equipment. The piston rod of the drive cylinder 10 and the rack 1308 adopt a floating clearance fit structure to completely avoid the transmission jamming problem caused by over-positioning during assembly, ensuring smooth and stable opening and closing actions. The main valve core 6 and the nozzle body 3 form a gap seal to prevent leakage when the flow channel is under low pressure. When the nozzle is opened to start injection, high pressure is established, and the pressure in the flow channel pushes the floating pin 5 to move upward and form a seal with the upper limit screw 4. At the same time, the main valve core 6 moves downward and forms a seal with the lower limit screw 7, which can effectively control the leakage under high pressure conditions.

[0028] Specifically, the upper limit screw 4 is equipped with a vent hole to discharge plastic stored in the upper gap, such as... Figure 3 As shown.

[0029] Through the above technical solution, the upper limit screw 4, which is assembled on the upper end of the main valve core 6, is made of heat-treated alloy steel, which has high structural strength and is resistant to high temperature and wear. A micro-drainage hole is opened at the center of the upper limit screw 4, and the hole diameter is machined to match the melt specifications. In the actual injection molding process, a small amount of melt will remain in the mating gap between the main valve core 6 and the upper limit screw 4 inside the nozzle. If the melt is left to stand at high temperature for a long time, it is prone to yellowing, carbonization and agglomeration, which will cause the main valve core 6 to jam and fail to open and close. This structure relies on the periodic pressure changes during the injection molding process, with the pressure rising and falling periodically during the high-pressure injection stage and the back pressure stage of material storage. It can automatically and slowly extrude residual glue trapped in the gaps, continuously cleaning the valve core mating clearance. This fundamentally prevents the melt from carbonizing and jamming the main valve core 6, significantly improving the stability of continuous equipment operation and reducing the frequency of equipment downtime for maintenance. When the main valve core 6 rotates to completely cover the flow channel hole, the valve core closes. A small hole is provided perpendicular to the valve core flow channel hole, near the material tube side. When the injection molding machine stores material, a higher back pressure is used to improve the plasticizing effect, resulting in more leakage. At this time, the small hole transmits the storage pressure to the main valve core flow channel hole, similar to the pressure built up during injection molding, thus achieving a seal.

[0030] Specifically, the upper end of the gearbox 1301 has two symmetrically arranged mounting brackets integrally formed, and these two mounting brackets precisely fix the gearbox 1301 module to the preset points on the outer wall of the nozzle body 3. Please refer to [link / reference]. Figure 5 .

[0031] Through the above technical solution, the transmission component 13 uses the gearbox 1301 as an independent mounting base. The gearbox 1301 is made of aluminum alloy casting, which is lightweight and has strong structural rigidity. It is not easy to deform and can effectively protect the internal transmission structure. The upper end of the gearbox 1301 has two symmetrically arranged mounting brackets. During assembly, the entire gearbox 1301 module is accurately fixed to the preset mounting point of the nozzle body 3 through the two brackets. The installation position is accurate and the disassembly and assembly are convenient. This split independent module structure breaks the traditional design of integrated welding and fixing of the transmission structure and the nozzle body 3. It can realize independent prefabrication and standardized assembly of the transmission mechanism, which greatly reduces the difficulty of equipment assembly, maintenance and replacement, and adapts to the needs of nozzle modification of different specifications of injection molding machines.

[0032] Specifically, the gearbox 1301 has symmetrically arranged assembly through holes on its upper and lower end faces. A lower bearing cover 1304 and an upper bearing cover 1305 are respectively installed within these through holes. Bearings 1303 are nested within the lower and upper bearing covers 1304 and 1305, and the gear shaft 1302 passes through the bearings 1303 to achieve axial and radial bidirectional limiting support. (See also...) Figure 5 .

[0033] Through the above technical solution, the gearbox 1301 has a gear transmission working chamber inside. The upper and lower end faces of the chamber are symmetrically opened with assembly through holes for assembling the lower bearing cover 1304 and the upper bearing cover 1305, respectively. Both bearing covers are made of wear-resistant cast iron, which has good positioning accuracy and wear resistance. High-precision rolling bearings 1303 are nested inside the lower bearing cover 1304 and the upper bearing cover 1305. The bearings 1303 are high-temperature resistant bearings, which can adapt to the long-term high-frequency start-stop and high-temperature working environment of injection molding equipment. The gear shaft 1302 passes through the bearing 1303 and is assembled with the upper and lower bearing covers. The two sets of upper and lower bearings 1303 realize axial and radial bidirectional limiting support, ensuring that the coaxiality of the gear shaft 1302 is accurate and there is no radial runout during the rotation. This effectively reduces the wear of the gear and rack meshing transmission, ensures the transmission accuracy and consistency of action, and avoids the problem of main valve core 6 opening and closing offset and incomplete closure during long-term operation.

[0034] Specifically, a wear-resistant block 1307 is mounted on the back of the rack 1308, and the wear-resistant block 1307 is locked and fixed to the inner wall of the gearbox 1301 by means of a wear-resistant block cover 1306. Please refer to [link / reference]. Figure 5 .

[0035] Through the above technical solution, the rack 1308, as the core linear transmission component, is precision-machined from high-hardness alloy steel. The tooth surfaces are hardened, resulting in extremely high wear resistance and fatigue strength. A wear-resistant block 1307 is fitted onto the back of the rack 1308. The wear-resistant block 1307 is made of polytetrafluoroethylene (PTFE), a wear-resistant material with an extremely low coefficient of friction, which significantly reduces the frictional resistance of the rack 1308's reciprocating sliding. The wear-resistant block 1307 is pressed and fixed to the inner wall of the gearbox 1301 by a metal wear-resistant block cover 1306, forming a support for the back of the rack 1308. The continuous limit support prevents the rack 1308 from shifting or warping due to force on one side, ensuring that the rack 1308 slides smoothly in a straight line throughout its entire stroke. This improves the meshing accuracy of the gear and rack and extends the service life of the entire transmission mechanism. Since the rotation does not need to complete a full circle, the drive gear 1310 is set as a non-full circle tooth structure. The toothed position of the gear is fixed with the axial position of the gear output shaft. The number of teeth on the rack 1308 is the same as the number of teeth on the drive gear 1310. The gears mesh completely from the first tooth, ensuring that the main valve core 6 rotates at a uniform angle each time it opens and closes, and that the nozzle on / off control accuracy is high.

[0036] Specifically, a limiting groove is provided on the wear-resistant block 1307, and a protrusion 1309 is integrally formed on the outer side of the rack 1308. The protrusion 1309 cooperates with the limiting groove, and the locking screw on the wear-resistant block cover 1306 limits the sliding of the rack 1308 within its stroke range to prevent the rack 1308 from falling out. Please refer to [link / reference]. Figure 5 .

[0037] Through the above technical solution, a limiting groove is opened on the inner side of the wear-resistant block 1307, and a protrusion 1309 limiting structure is integrally formed on the outer side of the rack 1308. The protrusion 1309 structure is adapted to the groove gap and fits precisely. At the same time, it is used with locking screws to complete auxiliary positioning and limiting. During the operation of the equipment, the rack 1308 moves in a high-frequency linear reciprocating motion with the piston rod of the drive cylinder 10. This limiting structure can strictly limit the effective sliding stroke of the rack 1308, avoid the rack 1308 from overtraveling and disengaging from the meshing position, and eliminate the faults of gear and rack tooth disengagement and transmission failure. At the same time, it can precisely control the sliding stroke of the rack 1308, ensure that the rotation angle of the main valve core 6 is uniform each time it is opened and closed, realize the standardized and precise operation of the nozzle on and off action, and adapt to the high-precision injection molding production requirements. The gearbox 1301 stroke is independently assembled module for easy standardization.

[0038] Specifically, the end face of the drive gear 1310 is engraved with alignment marks to indicate the nozzle status, and an observation window is provided on the side wall of the gearbox 1301 corresponding to the position of the drive gear 1310 to observe the opening and closing status of the main valve core 6. Please refer to [link / reference]. Figure 10 .

[0039] Through the above technical solution, a high-precision alignment mark is engraved on the outer gear end face of the gear shaft 1302. The mark is clear, wear-resistant, and not easily blurred by wear. At the same time, a transparent observation window is opened on the side wall of the gearbox 1301 corresponding to the gear working area. Since the main valve core 6 and the flow channel opening and closing structure are built into the nozzle body 3, the working status cannot be directly observed under closed working conditions. With the external gear mark and the observation window of the gearbox 1301, the staff can intuitively and quickly judge the opening and closing working status of the internal main valve core 6 during equipment operation without disassembling the machine for inspection or stopping the machine for disassembly. This greatly facilitates the daily debugging, working condition inspection and fault diagnosis of the equipment, and improves the efficiency of equipment operation and maintenance.

[0040] Specifically, one end of the nozzle body 3 is connected to an adapter 1 for connecting to the injection molding machine's feed tube, and the adapter 1 and the nozzle body 3 are connected via a flange 2. Multiple sets of flange bolts 8 are evenly arranged circumferentially on the flange 2 for locking and securing. Please refer to [link to relevant documentation]. Figure 3 .

[0041] Through the above technical solution, the feed end of the nozzle body 3 is equipped with an adapter head 1. The adapter head 1 is made of high-strength alloy steel and has a standard docking structure. It can be directly docked with the discharge end of the injection molding machine's material tube, which is highly versatile. The adapter head 1 and the nozzle body 3 are sealed together through the flange 2 structure. Multiple sets of flange bolts 8 are evenly arranged around the flange 2. The flange 2 end face is locked and fixed by the flange bolts 8 to ensure that the adapter head 1 and the nozzle body 3 are tightly docked and sealed, effectively preventing the problem of material leakage and overflow at the melt docking gap. At the same time, it is easy to disassemble and assemble, and facilitates the overall disassembly, replacement, maintenance and repair of the nozzle.

[0042] Specifically, coupling 9 is arranged between nozzle body 3 and transmission assembly 13 as a power transfer component between main valve core 6 and gear shaft 1302, and the bottom and sides of gearbox 1301 are locked and fixed by stainless steel anti-loosening screws 11. Please refer to Figure 2 .

[0043] Through the above technical solution, the coupling 9 is arranged between the nozzle body 3 and the transmission assembly 13, serving as the power transfer component between the main valve core 6 and the gear shaft 1302. The coupling 9 adopts an elastic coupling, which can buffer transmission vibration, compensate for minor coaxiality errors in assembly, and avoid component wear caused by rigid transmission. The bottom and sides of the gearbox 1301 of the transmission assembly 13 are locked and fixed by screws 11. The screws 11 are stainless steel anti-loosening screws, which have anti-rust and anti-loosening characteristics. The multi-point screw 11 fixing structure can improve the overall assembly firmness of the gearbox 1301, offset the loosening risk caused by equipment operation vibration, ensure the long-term structural stability of the entire transmission module, and prevent deviation and loosening, thus ensuring the stability and reliability of the nozzle opening and closing action.

[0044] Specifically, the length of the main valve core 6 is 0.05–0.2 mm shorter than the length of the valve core assembly hole, leaving an axial clearance of 0.05–0.2 mm between the main valve core 6 and the valve core assembly hole. This allows the main valve core 6 to complete its circumferential rotation without jamming within the valve core assembly hole. Please refer to [link to relevant documentation]. Figure 3 .

[0045] Through the above technical solution, the main valve core 6 is made of wear-resistant stainless steel, which is corrosion-resistant and has excellent wear resistance. The length of the main valve core 6 is slightly less than the length of the middle hole by 0.05 to 0.2 mm, so that the valve core can move in the nozzle body 3. That is, the main valve core 6 and the assembly hole are reserved with an axial gap of 0.05 mm to 0.2 mm, so that the main valve core 6 can complete the circumferential rotation without jamming in the valve core assembly hole. A small diameter connecting rod is set at one end of the main valve core 6 for power docking. The connecting rod is sleeved on the gear shaft 1302 through the coupling 9 to realize the rigid transmission of the rotational movement of the gear shaft 1302 and the circumferential rotational movement of the main valve core 6. The other end of the main valve core 6 is equipped with a high-hardness floating pin 5. The floating pin 5 is made of high-hardness alloy steel. The floating pin 5 is tightened with the upper limit screw 4 and the other end face of the main valve core 6 is tightened with the lower limit screw 7 to form an end face self-tightening seal.

[0046] Specifically, the protrusion 15 is a cylindrical boss integrally formed at the end of the piston rod, and the connecting groove 14 is a U-shaped groove opened at the end of the rack 1308. Please refer to [link / reference]. Figure 7 .

[0047] Through the above technical solution, the cylindrical boss integrally formed by the protrusion 15 and the U-shaped groove opened in the connecting groove 14 can make the protrusion 15 and the connecting groove 14 float and fit together, eliminating over-positioning during assembly.

[0048] During use, in the material storage stage, the injection molding system establishes back pressure. The melt pressure is introduced into the middle cavity of the main valve core 6 through the pressure transmission hole on the side wall of the nozzle body 3, establishing pressure and pushing the floating pin 5 to tighten the upper limit screw 4. The lower end of the main valve core 6 is attached to the lower limit screw 7. Relying on the pressure of the medium in the inner cavity, a self-tightening seal is formed to block the melt leakage gap in the material storage stage. The discharge hole opened by the upper limit screw 4 relies on the periodic rise and fall of the injection molding process pressure to slowly discharge the residual material stuck in the valve core gap.

[0049] The opening and closing action is achieved by the drive cylinder 10 and the transmission assembly 13: the protruding part 15 at the end of the piston rod of the drive cylinder 10 is fitted into the connecting groove 14 of the rack 1308. The extension and retraction action of the drive cylinder 10 drives the rack 1308 to move linearly back and forth. The rack 1308 meshes with the drive gear 1310 to transmit the linear motion, which is converted into the rotational motion of the drive gear 1310 and the gear shaft 1302. The gear shaft 1302 drives the main valve core 6 to rotate circumferentially inside the nozzle body 3 through the coupling 9. When the main valve core 6 rotates to the position of blocking the main flow channel, the nozzle is closed. When the main valve core 6 rotates to the position of fully opening the flow channel, the nozzle opens for material discharge.

[0050] The end face markings of the drive gear 1310 and the observation window on the side wall of the gearbox 1301 allow for direct external identification of the opening and closing status of the main valve core 6.

[0051] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various modifications, substitutions and alterations may be made to these embodiments without departing from the principles and spirit, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A split rotary valve core throttling nozzle with an integrated gear and rack drive device, comprising a nozzle body (3), a transmission assembly (13), a drive cylinder (10), a coupling (9), and a screw (11), characterized in that: The nozzle body (3) is generally cylindrical and wrapped with a heating coil (12). A flow channel is provided through the left and right sides along the axis of the nozzle body (3). A valve core assembly hole perpendicular to the flow channel is provided in the middle of the nozzle body (3) for installing the main valve core (6). A connecting rod with a diameter smaller than that of the main valve core (6) extends out from one end of the main valve core (6) for manipulating the rotation of the main valve core (6). A floating pin (5) is installed at the other end of the main valve core (6). An upper limit screw (4) is screwed into the valve core assembly hole near the floating pin (5) and a lower limit screw (7) is screwed into the valve core assembly hole near the connecting rod. The transmission assembly (13) includes a gearbox (1301), and a drive gear (1310) is provided inside the gearbox (1301). A gear shaft (1302) is connected above the drive gear (1310), and a rack (1308) meshes with one side of the gear. A connecting groove (14) is provided at one end of the rack (1308). A piston rod is connected to the output end of the drive cylinder (10), and a protrusion (15) is provided at one end of the piston rod. The protrusion (15) is fitted into the connecting groove (14) with clearance. The drive cylinder (10) is floatingly connected to the rack (1308).

2. The split rotary valve core throttling nozzle of the integrated gear and rack drive device according to claim 1, characterized in that: The upper limit screw (4) is provided with a discharge hole for discharging plastic stored in the upper gap.

3. The split rotary valve core throttling nozzle of the integrated gear and rack drive device according to claim 1, characterized in that: The gearbox (1301) has two symmetrically arranged mounting brackets integrally formed on the upper end, and the two mounting brackets precisely fix the gearbox (1301) module to the preset position on the outer wall of the nozzle body (3).

4. The split rotary valve core throttling nozzle of the integrated gear and rack drive device according to claim 1, characterized in that: The gearbox (1301) has symmetrically arranged assembly through holes on its upper and lower ends. The lower bearing cover (1304) and the upper bearing cover (1305) are respectively installed in the assembly through holes. The lower bearing cover (1304) and the upper bearing cover (1305) are nested and installed with bearings (1303). The gear shaft (1302) passes through the bearings (1303) to achieve axial and radial bidirectional limiting support.

5. The split rotary valve core throttling nozzle of the integrated gear and rack drive device according to claim 1, characterized in that: Wear-resistant blocks (1307) are installed on the back of the rack (1308), and the wear-resistant blocks (1307) are locked and fixed to the inner wall of the gearbox (1301) by means of wear-resistant block cover (1306).

6. The split rotary valve core throttling nozzle of the integrated gear and rack drive device according to claim 5, characterized in that: The wear-resistant block (1307) has a limiting groove, and the outer side of the rack (1308) is integrally formed with a protrusion (1309). The protrusion (1309) cooperates with the limiting groove. The locking screw on the wear-resistant block cover (1306) limits the rack (1308) to slide within the stroke range, so as to prevent the rack (1308) from coming out.

7. The split rotary valve core throttling nozzle of the integrated gear and rack drive device according to claim 1, characterized in that: The end face of the drive gear (1310) is engraved with alignment marks to indicate the nozzle status, and the side wall of the gearbox (1301) is provided with an observation window corresponding to the position of the drive gear (1310) to observe the opening and closing status of the main valve core (6).

8. The split rotary valve core throttling nozzle of the integrated gear and rack drive device according to claim 1, characterized in that: One end of the nozzle body (3) is connected to an adapter (1) for connecting the injection molding machine tube, and the adapter (1) and the nozzle body (3) are connected by a flange (2), and the flange (2) is circumferentially arranged with multiple sets of flange bolts (8) for locking and fixing.

9. The split rotary valve core throttling nozzle of the integrated gear and rack drive device according to claim 1, characterized in that: The coupling (9) is arranged between the nozzle body (3) and the transmission assembly (13) as a power transfer component between the main valve core (6) and the gear shaft (1302), and the bottom and sides of the gearbox (1301) are locked and fixed by stainless steel anti-loosening screws (11).

10. The split rotary valve core throttling nozzle of the integrated gear and rack drive device according to claim 1, characterized in that: The length of the main valve core (6) is 0.05 to 0.2 mm shorter than the length of the valve core assembly hole, so that the main valve core (6) and the valve core assembly hole have an axial gap of 0.05 to 0.2 mm, and the main valve core (6) can complete the circumferential rotation without jamming in the valve core assembly hole.

11. The split rotary valve core throttling nozzle of the integrated gear and rack drive device according to claim 1, characterized in that: The protrusion (15) is a cylindrical boss integrally formed at the end of the piston rod, and the connecting groove (14) is a U-shaped groove opened at the end of the rack (1308).

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