Sleeved variable-pitch plasticizing screw rod for injection machine

Abstract

The utility model discloses a cup joint variable pitch plasticizing screw for an injection machine, the cup joint variable pitch plasticizing screw is of a double-layer structure and comprises a plasticizing screw and a cooling screw, the inside of the plasticizing screw is of a hollow structure, the plasticizing screw is sleeved outside the cooling screw, and the cooling screw is sleeved outside the plasticizing screw. And the inner diameter of the plasticizing screw rod is greater than the outer diameter of the cooling screw rod.

Description

Technical Field

[0001] The utility model belongs to the technical field of injection molding, and relates to a socket variable pitch plasticizing screw for an injection molding machine, which is applicable to high-precision and high-efficiency injection molding operations. Background Art

[0002] Injection molding equipment is widely used in the production of plastic or rubber products, and its performance directly affects the quality and production efficiency of products. The existing injection molding equipment has the following deficiencies in mold positioning and screw temperature control:

[0003] Low precision of the mold positioning system: The traditional mold positioning system usually uses mechanical limit or simple sensors for positioning. This method has low precision and is easily affected by mechanical wear and environmental changes, resulting in positioning errors. Positioning errors will affect the dimensional accuracy and appearance quality of products. Especially when producing plastic or rubber products with high-precision requirements, the problem of positioning errors is particularly prominent.

[0004] Lag and instability of the screw temperature control system: Most of the existing screw temperature control systems use traditional electric heaters and simple temperature controllers. This system has hysteresis in temperature control and cannot quickly respond to temperature changes. In addition, the accuracy and stability of the temperature control system are poor, which easily leads to uneven temperature during the melting process of plastics or rubbers, thereby affecting the quality of products. Especially when producing plastic or rubber products of different materials, the hysteresis and instability of the temperature control system will cause the performance of the materials not to be fully exerted.

[0005] Low production efficiency: Due to the insufficient precision and efficiency of the mold positioning and screw temperature control systems, the existing injection molding equipment needs to be frequently adjusted and corrected during the production process, resulting in low production efficiency. This not only increases the production cost but also prolongs the production cycle, which is not conducive to the competitiveness of enterprises.

[0006] High energy consumption: Due to its low efficiency, the traditional screw temperature control system wastes a large amount of energy during the heating process, increasing the production cost. In today's situation where environmental protection requirements are becoming increasingly strict, high-energy-consuming equipment will face more restrictions and challenges.

[0007] Complex operation and difficult maintenance: The existing injection molding equipment usually requires operators to have high professional skills for adjustment and maintenance when problems occur. This not only increases the labor cost but also limits the popularization and application of the equipment. During the operation of the equipment, operators need to continuously monitor and adjust various parameters to ensure the smooth progress of production. This complex operation process increases the possibility of errors and also places high requirements on the professional level of operators. Summary of the Utility Model

[0008] To address the deficiencies of the prior art, the purpose of the present utility model is to provide a socket variable pitch plasticizing screw for an injection molding machine to improve production efficiency and product quality.

[0009] The present utility model provides a socket variable pitch plasticizing screw for an injection molding machine, which is a double-layer structure and includes a plasticizing screw and a cooling screw. The interior of the plasticizing screw is a hollow structure. The plasticizing screw is sleeved outside the cooling screw, and the inner diameter of the plasticizing screw is larger than the outer diameter of the cooling screw. The plasticizing screw is divided into multiple regions along the length direction, successively including a support and sealing region, a first plasticizing region, a second plasticizing region, a third plasticizing region, and a melt guiding region; the cooling screw includes a spiral cooling region, a coolant return channel, and a rotary joint.

[0010] In the present utility model, the support and sealing region is at one end of the plasticizing screw close to the driving structure, with a smooth surface, connected to the driving shaft or coupling to transmit the driving force;

[0011] The melt guiding region is at the other end of the plasticizing screw far from the driving structure, that is, the end of the plasticizing screw, and is conical. Through the conical structure, the melt guiding region increases the pressure of the rubber melt to ensure that the melt is completely homogenized before entering the mold and increases the pressure entering the injection barrel;

[0012] On the first plasticizing region, the second plasticizing region, and the third plasticizing region, helical lines are processed through processes including turning, milling, grinding, and roll forming, with the corners rounded. The line shapes of the helical lines include involute shape, circular arc shape, parabolic shape, hyperbolic shape, and waveform shape;

[0013] The first plasticizing region is at the front of the plasticizing screw. Helical lines are processed on the first plasticizing region. The pitch range of the helical lines is 30 - 35 mm, preferably 35 mm; the thread angle is 30°, the upper side of the trapezoidal thread cross-section is 5.5 mm, and the lower side is 18.9 mm; the proportion of the first plasticizing region in the entire plasticizing region is 25.51%.

[0014] The second plasticizing region is at the middle of the plasticizing screw. Helical lines are processed on the second plasticizing region. The pitch range of the helical lines is 50 - 55 mm, preferably 55 mm, the thread angle is 30°, the upper side of the trapezoidal thread cross-section is 5.5 mm, and the lower side is 18.9 mm; the proportion of the second plasticizing region in the entire plasticizing region is 61.22%.

[0015] The third plasticizing region is at the rear of the plasticizing screw. Helical lines are processed on the third plasticizing region. The pitch range of the helical lines is 30 - 35 mm, preferably 35 mm, the thread angle is 30°, the upper side of the trapezoidal thread cross-section is 5.5 mm, and the lower side is 18.9 mm; the proportion of the third plasticizing region in the entire plasticizing region is 13.27%.

[0016] In the present utility model, the spiral cooling zone corresponds to the plasticizing zone of the plasticizing screw, and is provided with a first spiral cooling zone, a second spiral cooling zone, and a third spiral cooling zone. The rotary joint is exposed outside the plasticizing screw. One end of the rotary joint is connected to the original rotating inlet, and the other end is connected to the fixed cooling water inlet and the cooling water outlet. The front ends of the cooling screw and the plasticizing screw are fixed by a welding structure.

[0017] A first groove that penetrates up and down along the length direction is opened on the side of the connection port between the cooling zone and the coolant return channel. One end of the first groove is connected to the starting point of the spiral groove in the spiral cooling zone. To connect the spiral cooling flow channel and the coolant return channel, its shape is a frustum of a cone, and the diameters at both ends are equal to the diameters of the corresponding flow channels. The ratio of the diameter of the coolant spiral flow channel to the radius of the coolant return channel is

[0018] The spiral cooling zone is a region composed of continuously spiral grooves machined on the outside of the cooling screw. The spiral grooves in the spiral cooling zone and the inner wall of the plasticizing screw together form the flow channel for the coolant.

[0019] The first spiral cooling zone corresponds to the first plasticizing zone of the plasticizing screw. The spiral of the first spiral cooling zone is a linearly variable pitch along the center line. The first pitch is 120 mm, and the proportion it occupies is equal to the proportion occupied by the first plasticizing zone.

[0020] The second spiral cooling zone corresponds to the second plasticizing zone of the plasticizing screw. The spiral of the second spiral cooling zone is a linearly variable pitch along the center line. The second pitch is 200 mm, and the proportion it occupies is equal to the proportion occupied by the second plasticizing zone.

[0021] The third spiral cooling zone corresponds to the third plasticizing zone of the plasticizing screw. The spiral of the third spiral cooling zone is a linearly variable pitch along the center line. The third pitch is 80 mm, and the proportion it occupies is equal to the proportion occupied by the third plasticizing zone.

[0022] Based on the above, the present utility model provides an injection molding machine with an intelligent temperature control and a precision positioning structure. The injection molding machine includes: a plasticizing and injection system, a clamping system, a driving system, and a heating and cooling system.

[0023] In the present utility model, the plasticizing and injection system includes a plasticizing device and an injection device. The plasticizing device includes a plasticizing barrel and a socket variable pitch plasticizing screw installed inside the plasticizing barrel. The injection device includes an injection barrel, an upper hot plate with multiple injection holes, and a lower hot plate.

[0024] The plasticizing barrel is used to accommodate the rubber raw material and generate heat through the action of rotational shear to increase its fluidity. The rubber raw material is plasticized through the rotation and shear action of the socket variable pitch plasticizing screw.

[0025] The syringe melts the rubber and injects it into the mold. An injection screw is arranged inside the syringe, and the plasticized rubber is pushed towards the mold through the rotation and advancement of the injection screw via the injection port.

[0026] The multi-injection-hole upper hot plate is the fixing and heating plate of the upper mold of the mold. One or more injection ports are arranged on the multi-injection-hole upper hot plate, and the syringe injects the plasticized rubber into the mold through the injection port.

[0027] The lower hot plate is the fixing plate of the lower mold of the mold, and the other part of the mold is fixed on this plate.

[0028] The mold clamping system includes an electrically controlled sliding positioning device and a displacement plate with positioning.

[0029] The driving system includes a hydraulic device driven by hydraulic oil in the oil pipeline.

[0030] The heating and cooling system includes a cooling system, cooling pipelines, and an electrically controlled screw temperature control device.

[0031] In the present utility model, the multi-injection-hole upper hot plate is a multi-level structure, which includes an upper heat insulation plate, an upper plate temperature oil layer, a nozzle temperature oil layer, a lower plate temperature oil layer, a lower heat insulation plate, a hot plate, and a back plate from top to bottom. Among them,

[0032] The upper heat insulation plate is located above the upper plate temperature oil layer and is in direct contact with the upper plate temperature oil layer, used to isolate heat, prevent heat from conducting to the upper layer, and protect the injection runner.

[0033] The upper plate temperature oil layer is located between the upper heat insulation plate and the nozzle temperature oil layer and is in direct contact with the upper heat insulation plate and the nozzle temperature oil layer; the nozzle temperature oil layer is located between the upper plate temperature oil layer and the lower plate temperature oil layer, connecting the upper and lower temperature oil layers; the lower plate temperature oil layer is located between the nozzle temperature oil layer and the lower heat insulation plate and is in direct contact with the nozzle temperature oil layer and the lower heat insulation plate; the upper plate temperature oil layer, the nozzle temperature oil layer, and the lower plate temperature oil layer are all used to cool the runner.

[0034] A set of cooling oil circulation system is connected to the upper plate temperature oil layer, the nozzle temperature oil layer, and the lower plate temperature oil layer.

[0035] The lower heat insulation plate is located below the lower plate temperature oil layer and is in direct contact with the lower plate temperature oil layer, used to isolate heat, prevent the temperature of the hot plate during vulcanization from conducting to the lower plate temperature oil layer, the nozzle temperature oil layer, and the upper plate temperature oil layer.

[0036] The hot plate is located between the lower heat insulation plate and the back plate, generates heat through the internal heating element, and is used to heat the hot plate by electric heating or hot steam to provide heat for the products on the vulcanizing machine table, so that the rubber products can complete the vulcanization process.

[0037] The back plate is located below the hot plate and is in direct contact with the hot plate, supports the hot plate and is tightly connected to other structural components, used to support the hierarchical structure, maintain the stability and strength of the whole structure, and play a role in heat transfer.

[0038] There are multiple injection nozzles provided on the back plate. The upper end of the injection nozzle is connected to the upper heat insulation plate. Rubber enters the cavity of the injection nozzle through the injection runner. The cavity is directly connected to the upper plate warm oil layer, the nozzle warm oil layer, and the lower plate warm oil layer to reduce the internal rubber temperature and avoid scorching or old rubber blocking the injection nozzle. There is a gap between the lower half of the injection nozzle and the lower heat insulation plate and the hot plate to prevent direct contact with the hot plate and cause too high internal rubber temperature.

[0039] The injection nozzle is designed with double-layer heat insulation. A cavity is made between the outer layer and the inner layer to reduce the direct contact area between the injection nozzle and the back plate and slow down the heating rate of the nozzle tail end temperature, so as to reduce the scorching and aging rates of the rubber at the corresponding position.

[0040] An injection cavity is provided corresponding to each injection nozzle. The injection cavity penetrates through the nozzle warm oil layer, the lower plate warm oil layer, the lower heat insulation plate, the hot plate, and the back plate and is connected to the outside through the injection nozzle.

[0041] An injection runner connecting the plasticizing barrel and the injection cavity is provided in the nozzle warm oil layer. The plasticized rubber enters the injection cavity from the plasticizing barrel through the injection runner.

[0042] Cold runners are provided around the injection cavity in the upper plate warm oil layer and the lower plate warm oil layer. Coolant flows through the cold runners to control the temperature of the plasticized rubber entering the injection cavity.

[0043] An electromagnetic valve is inlaid in the back plate near the injection nozzle. The electromagnetic valve can be switched on and off in the back plate. The electromagnetic valve plug in it can block the injection nozzle to control the number and injection positions of the injection nozzles for injection operations.

[0044] The injection nozzles on the back plate are divided into 3 groups, with 4 in each group. Taking the rectangle center as the coordinate origin, the coordinates of the four injection nozzles in the first group are (550, 550), (-550, 550), (-550, -550), (550, -550); the coordinates of the four injection nozzles in the second group are (550, 0), (0, 550), (-550, 0), (0, -550); the coordinates of the four injection nozzles in the third group are (350, 200), (-350, 200), (-350, -200), (350, -200).

[0045] In the present utility model, a double ejector pin system is also included in supporting the plasticizing injection system. The double ejector pins are used to eject the molded product to ensure the smooth demolding of the product.

[0046] In the present utility model, the electric control sliding positioning device is used to accurately control the position of the moving parts to ensure the accuracy and repeatability during the injection process.

[0047] The displacement plate with positioning is used to fix and move the mold to ensure the stable position of the mold during the injection process.

[0048] The oil pipeline is used to transport hydraulic oil, control the actions of each hydraulic component, and realize the injection, mold clamping, and mold opening actions;

[0049] The cooling system is used to cool the injection runner to prevent the temperature from being too high, which may cause the mixing rubber in the injection runner to scorch or even age, affecting the product quality or blocking the injection runner; the mixing rubber is the rubber obtained by uniformly mixing raw rubber and various raw materials through a Banbury mixer.

[0050] The cooling pipeline is used to cool the plasticizing screw, plasticizing barrel, and / or the injection cavity in the hot plate of the multi-injection holes to prevent the temperature from being too high and affecting the fluidity and injection quality of the rubber;

[0051] The electric control screw temperature control device is used to control the temperature of the socket variable pitch plasticizing screw and the plasticizing barrel to ensure the uniformity and stability of the melting of the rubber raw materials.

[0052] The electric control sliding positioning device includes a PLC motor, a driving gear, multiple driven supporting gears, a double-sided rack, a positioning slider, an electronic scale, a tail end baffle, and a hydraulic lifting device;

[0053] The PLC motor is fixedly connected to the driving gear to drive the driving gear to rotate;

[0054] Multiple driven supporting gears are in pairs up and down, forming multiple pairs of driven gear groups, which are arranged on the gear bracket and can rotate on the gear bracket;

[0055] The centers of the multiple driven supporting gears located below are on a straight line with the center of the driving gear, and the centers of the multiple driven supporting gears located above are on a straight line. The two straight lines are parallel to the movement direction of the double-sided rack;

[0056] The double-sided rack is arranged between the upper and lower driven supporting gears of multiple pairs of driven gear groups and above the driving gear;

[0057] The teeth on the double-sided rack match the teeth of the driving gear and / or the driven supporting gears and are in contact and meshed with the driven supporting gears and / or the driving gear; the double-sided rack can move back and forth along the length direction of the double-sided rack driven by the driving gear and / or the driven supporting gears;

[0058] The front end of the double-sided rack is provided with a positioning slider. The front end of the positioning slider is set in the shapes of semi-circular, square, and triangular; a positioning head is arranged on the upper part of the positioning slider, and the shape and size of the positioning head can match the mold positioning groove arranged on the bottom edge of the mold;

[0059] The electronic scale is fixedly arranged on the side of the double-sided rack to measure the moving distance of the double-sided rack and transmit the data to the PLC motor control system for positioning;

[0060] The end baffle is arranged at the outer end of the movement path of the double-sided rack, on the side far away from the positioning slider, to prevent the double-sided rack and / or the positioning slider from exceeding the stroke range and ensure safety;

[0061] The PLC motor, the gear support, and the end baffle are all fixedly arranged on the upper plane of the hydraulic lifting support. The lower plane of the hydraulic lifting support is connected to the hydraulic lifting device, and the height can be changed through the hydraulic lifting device, thereby driving the PLC motor, the gear support, and the end baffle fixed above the hydraulic lifting support to move up and down accordingly.

[0062] In the present utility model, the displacement plate with positioning is a flat plate with a length sufficient for mold positioning, used for positioning the injection mold; grooves are opened on the relative two sides of its upper surface from the edge to the inside to ensure that all molds can be positioned to the injection position. The innermost end of the groove can be set as a semi-circular arc, a square or a triangle, which matches the shape of the top end of the positioning slider. The positioning slider can slide in the groove driven by the double-sided rack;

[0063] Preferably, the displacement plate with positioning is 1600mm x 1800mm; the length of the groove is 600mm, the width is 58.8mm, and the depth is 25mm.

[0064] In the present utility model, the electric control screw temperature control device includes a device shell, a PLC control motor, a planetary speed reducer, a drive shaft, a drive gear, a driven gear, a positioning ring, a solid pin, and a hollow pin;

[0065] One or more electric control screw temperature control devices are included, which are generally annular and sleeved outside the plasticizing barrel;

[0066] The device shell is fixed on the socketed variable pitch plasticizing screw through bolts and / or brackets, wrapping the internal components to protect the internal components from the influence of the external environment;

[0067] The PLC control motor is installed above the device shell; a motor support plate is also fixedly arranged on the PLC control motor, and the motor support plate is fixed on the device shell through bolts to provide a stable support platform for the PLC control motor; the motor support plate can support and fix the PLC control motor, absorb vibration, and ensure that the motor remains stable during operation; the PLC control motor is directly connected to the plasticizing screw, and a flat plate is set to level the position.

[0068] The output end of the PLC control motor is connected to the planetary speed reducer. The input shaft of the planetary speed reducer is connected to the output shaft of the PLC control motor through a coupling, and the body of the planetary speed reducer is fixed on the motor support plate or a fixed bracket through bolts;

[0069] The output end of the planetary speed reducer is connected to the drive shaft. The drive shaft passes through the device housing and the positioning ring arranged inside the device housing from outside the device housing, extends into the device housing, and its end is connected to the drive gear.

[0070] After the output speed of the PLC-controlled motor is adjusted by the planetary speed reducer, the drive gear is driven to rotate via the drive shaft.

[0071] A plurality of driven gears are arranged on both sides of the drive gear, and the drive gear meshes with the driven gears or the driven gears mesh with each other in sequence; the drive gear or the driven gears are helical bevel gears.

[0072] The positioning ring is arranged inside the device housing and is concentric with the device housing; on the plurality of driven gears on both sides of the drive gear, hollow pins and solid pins are arranged in sequence, and the hollow pins and the solid pins are arranged at intervals; the angle between the drive shaft and two adjacent hollow pins is 30°, and the angle between two adjacent hollow pins and solid pins is 30°.

[0073] One end of the solid pin is rotatably connected to the positioning ring, and the other end serves as the drive shaft of the driven gear and is fixedly connected to the driven gear; the hollow pin includes a hollow rotating shaft sleeve, a driven temperature control shaft, and a temperature control head. One end of the hollow rotating shaft sleeve of the hollow pin is rotatably connected to the positioning ring, and the other end passes through the axis of the driven gear and is inserted into the plasticizing barrel all the way. A thread is arranged between the driven temperature control shaft and the temperature control head, and it can be screwed in and out on the wall of the plasticizing barrel to change the insertion depth of the temperature control head in the plasticizing barrel; a temperature sensor is arranged on the temperature control head, which can monitor the rubber temperature in the plasticizing barrel in real time.

[0074] The gear rim of the helical bevel gear is conical, and the tooth line is inclined relative to the gear axis and can mesh with another gear of a similar shape; due to the inclination of the tooth line relative to the gear axis, the contact area of gear meshing is increased, the transmission smoothness and load capacity are improved; it has an efficient power transmission capacity during the transmission process and can withstand a large torque, realizing the steering and transmission of power between the drive gear and the driven gears or the driven gears.

[0075] When the temperature control head detects that the rubber temperature in the plasticizing barrel fails to reach the preset temperature, the PLC-controlled motor is started. The output shaft of the motor rotates, the planetary speed reducer adjusts the speed output by the output shaft of the motor, and drives the drive gear to rotate through the drive shaft. The drive gear drives the driven gears to rotate, and the hollow pins fixedly connected to several of the driven gears are screwed into the interior of the plasticizing barrel. Preferably, when the temperature control head is partially inserted into the spiral line position of the plasticizing screw, it is equivalent to encrypting the spiral line. After the spiral line is encrypted, the contact area between the screw and the rubber increases, and at the same time, the flow path of the rubber inside the screw becomes shorter, the flow rate increases, the flow resistance increases, the internal pressure rises, and the shear force received by the rubber also increases.

[0076] When the temperature control head detects that the temperature of the rubber in the plasticizing barrel exceeds the preset temperature, the PLC is activated to control the motor. The output shaft of the motor rotates in the reverse direction. The planetary reducer adjusts the rotational speed output by the output shaft of the motor, and drives the driving gear to rotate in the reverse direction through the drive shaft. The driving gear drives the driven gear to rotate in the reverse direction, and the hollow pins fixedly connected to several of the driven gears are screwed out of the interior of the plasticizing barrel. Preferably, when the temperature control head is partially pulled out from the helical position of the plasticizing screw, it is equivalent to reducing the density of the helix. After the helix density is reduced, the contact area between the screw and the rubber decreases. At the same time, the flow path of the rubber inside the screw becomes longer, the flow rate decreases, the flow resistance decreases, the internal pressure decreases, and the shear force applied to the rubber decreases.

[0077] The present utility model also provides the application of the above injection machine or the above injection molding method in the molding production and processing of plastic or rubber products.

[0078] The beneficial effects of the present utility model include: The plasticizing screw is driven by a motor, which has low energy consumption, low noise, simple maintenance, and has high-precision control and fast response capabilities, significantly improving the molding accuracy and production efficiency. The advanced control system enables high-precision parameter adjustment and full-process automated operation, with real-time monitoring and feedback to ensure the stability and consistency of the production process. Overall, the optimized injection machine has significant improvements in energy conservation and environmental protection, operating accuracy, response speed, ejection force, and automation level, overcoming the problems of high energy consumption, high noise, low control accuracy, and high maintenance costs in the prior art, and greatly enhancing the performance and production efficiency of the injection molding machine. Description of the Drawings

[0079] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0080] Figures 1a - 1c It is a schematic diagram of the overall structure of the injection machine with an intelligent temperature control and precise positioning structure of the present utility model.

[0081] Figure 2 It is a schematic diagram of the structure of the plasticizing and injection part of the present utility model.

[0082] Figure 3 It is a three-dimensional structure diagram of the upper hot plate of the injection machine of the present utility model.

[0083] Figures 4a - 4c It is a schematic diagram of the injection surface and cross-sectional structure of the upper hot plate of the injection machine of the present utility model.

[0084] Figure 5a 、 Figure 5b are the schematic diagrams of the precision positioning drive structure and the moving plate structure of the mold of the present utility model.

[0085] Figure 6 is the schematic diagram of the electric control sliding positioning device structure of the present utility model.

[0086] Figures 7a - 7c is the schematic diagram of the socket variable pitch screw structure of the present utility model.

[0087] Figure 8 is the schematic diagram of the equal pitch screw structure in the prior art.

[0088] Figures 9a - 9d is the schematic diagram of the electric control screw temperature control device structure of the present utility model.

[0089] Figures 1a - 9d In

[0090] 11 - plasticizing barrel; 111 - plasticizing inlet; 12 - socket variable pitch plasticizing screw; 121 - plasticizing screw; 1211 - support sealing area; 1212 - first plasticizing area; 1213 - second plasticizing area; 1214 - third plasticizing area; 1215 - melt guiding area; 1216 - helix; 12161 - helix groove; 122 - cooling screw; 1221 - spiral cooling area; 12211 - first spiral cooling area; 12212 - second spiral cooling area; 12213 - third spiral cooling area; 1222 - coolant return channel; 12221 - connection port between the cooling area and the coolant return channel; 1223 - rotary joint; 1224 - first groove; 1225 - cooling water inlet; 1226 - cooling water outlet; 13 - injection barrel; 14 - multi-injection hole upper hot plate; 141 - injection port; 1411 - injection flow path; 142 - upper heat insulation plate; 143 - upper plate temperature oil layer; 144 - nozzle temperature oil layer; 145 - lower plate temperature oil layer; 146 - lower heat insulation plate; 147 - hot plate; 148 - back plate; 1481 - injection nozzle; 1482 - solenoid valve; 1483 - solenoid valve plug; 149 - cold runner; 15 - lower hot plate

[0091] 21 - electric control sliding positioning device; 211 - PLC motor; 212 - driving gear; 213 - driven supporting gear; 214 - double-sided rack; 215 - positioning slider; 2151 - positioning head; 216 - electronic scale; 217 - tail end baffle; 218 - hydraulic lifting device; 22 - moving plate with positioning; 221 - second groove

[0092] 31 - hydraulic device driven by hydraulic oil

[0093] 41 - Cooling system; 43 - Electric control screw temperature control device; 431 - Device housing; 4311 - Positioning ring; 432 - PLC control motor; 433 - Planetary reducer; 434 - Drive shaft; 435 - Driving gear; 436 - Driven gear; 438 - Solid pin; 439 - Hollow pin; 4391 - Hollow rotating shaft sleeve; 4392 - Driven temperature control shaft; 4393 - Temperature control head; 440 - Motor support plate; 45 - Cooling water inlet; 46 - Injection and cold runner connection port;

[0094] 5 - Double ejector pin system;

[0095] 61 - Oil pipeline;

[0096] 7 - Ejector device. Detailed implementation manner

[0097] Combined with the following specific embodiments and drawings, the present utility model will be further described in detail. The processes, conditions, experimental methods, etc. for implementing the present utility model, except for the specifically mentioned content below, are all common knowledge and well-known common sense in the art, and the present utility model has no particularly restricted content.

[0098] The present utility model provides an injection molding machine with intelligent temperature control and precise positioning, and the injection molding machine includes: a plasticizing and injection system, a mold clamping system, a driving system, a heating and cooling system;

[0099] The plasticizing and injection system further includes a plasticizing device and an injection device;

[0100] The plasticizing device includes a plasticizing barrel and a socket variable pitch plasticizing screw installed inside the plasticizing barrel; the plasticizing barrel is used to accommodate rubber raw materials and generate heat through the action of rotational shearing to increase its fluidity, and the rubber raw materials are plasticized through the rotation and shearing action of the socket variable pitch plasticizing screw;

[0101] The injection device includes an injection barrel, a multi-injection hole upper hot plate, and a lower hot plate; the injection barrel melts rubber and injects it into the mold; an injection screw is arranged inside the injection barrel, and the plasticized rubber is pushed towards the mold through the rotation and advancement of the injection screw; the multi-injection hole upper hot plate is the fixing and heating plate of the upper mold of the mold, and one or more injection ports are arranged on the multi-injection hole upper hot plate, and the injection barrel injects the molten rubber into the mold through the injection ports; the lower hot plate is the fixing plate of the lower mold of the mold, and the other part of the mold is fixed on this plate;

[0102] The mold clamping system includes an electric control sliding positioning device and a positioning movable plate; the electric control sliding positioning device is used to precisely control the position of the moving parts to ensure the accuracy and repeatability during the injection process; the positioning movable plate is used to fix and move the mold to ensure the stable position of the mold during the injection process;

[0103] The electric control sliding positioning device is used to position and fix the mold on the positioning moving plate. The positioning moving plate sends the mold into the space between the upper hot plate with multiple injection holes and the lower hot plate through a slide rail. The lower hot plate can be controlled to lift and lower by a hydraulic cylinder. During actual use, by controlling the lifting height of the hydraulic cylinder, the mold is firmly fixed between the upper hot plate with multiple injection holes and the lower hot plate, facilitating the injection operation.

[0104] The drive system includes a hydraulic device driven by hydraulic oil in an oil pipeline; the oil pipeline is used to transport hydraulic oil, control the actions of various hydraulic components, and realize actions such as injection, mold clamping, and mold opening; the hydraulic device includes a hydraulic lifting device that drives the hydraulic lifting bracket in the electric control sliding positioning device through hydraulic oil in the oil pipeline, a hydraulic cylinder that drives the lifting and lowering of the lower hot plate, a hydraulic ejector that drives the double ejector pins system to eject the molded product, a hydraulic syringe that drives the injection cylinder to perform injection operations, and / or a hydraulic motor that drives the socket variable pitch plasticizing screw to rotate, etc.

[0105] The heating and cooling system includes a cooling system, a cooling pipeline, and an electric control screw temperature control device; the cooling system is mainly used to cool the heat generated during injection to prevent the machine from overheating and affecting production efficiency and product quality; the cooling pipeline is used to cool the plasticizing screw, the plasticizing barrel, and / or the injection cavity in the upper hot plate with multiple injection holes to prevent the temperature from being too high and affecting the fluidity and injection quality of the rubber; the electric control screw temperature control device is used to control the temperature of the plasticizing screw and the plasticizing barrel to ensure the uniformity and stability of the melting of the rubber raw material;

[0106] The coolant in the cooling system cools down the injection cavity in the plasticizing screw and / or the upper hot plate with multiple injection holes through the cooling pipeline. The electric control screw temperature control device adjusts the shear force and temperature of the rubber in the plasticizing barrel by changing the insertion depth of the hollow pin in it.

[0107] In addition, the injection molding machine also includes a double ejector pins system, which is used to eject the molded product to ensure that the product can be smoothly demolded. The ejecting device is used to eject the product. The hydraulically driven double ejector pins system provides strong and stable ejecting force, is suitable for complex and large-sized products, has smooth actions, and reduces product damage.

[0108] The injection molding method of this embodiment, the injection method includes:

[0109] Step 1: Put the required processed and kneaded rubber into the hopper, which is connected to the plasticizing barrel, and set and check the temperature of the plasticizing barrel and the rotation speed of the socket variable pitch plasticizing screw;

[0110] Step 2: Start the socket variable pitch plasticizing screw to rotate. Under the rotation and shearing action of the socket variable pitch plasticizing screw, the processed mixed rubber is plasticized into a molten state. Monitor and maintain the plasticizing temperature within the set range to ensure uniform melting of the raw materials;

[0111] Step 3: Ensure that the mold is installed and accurately positioned. Preset injection parameters including injection pressure, injection speed, and holding pressure time. Heat the mold and adjust the mold temperature to the set temperature;

[0112] Step 4: Start the injection screw, push the molten rubber from the plasticizing barrel into the injection barrel, advance the injection screw, and inject the molten rubber into the mold cavity through the injection port; maintain the injection pressure and holding pressure time until the mold cavity is filled with rubber;

[0113] Step 5: Stop injection, keep the mold closed, start the cooling system, and the cooling system cools the mold and the socket variable pitch plasticizing screw to reduce the temperature and solidify the rubber product;

[0114] Step 6: After cooling, start the mold opening and closing system, open the mold, start the double ejector pin system, and eject the formed rubber product from the mold.

[0115] In Step 1, the temperature of the plasticizing barrel is 70 - 80°C; the rotation speed of the socket variable pitch plasticizing screw is 0 - 90 revolutions per minute.

[0116] In Step 2, the plasticizing time is 1 minute for 0 - 10 Kg of mixed rubber.

[0117] In Step 3, the injection pressure is 200 Bar (20 Mpa); the injection speed is 0 - 280 cc / s (same as cm 3 / s or mL / s); the holding pressure time is 15 s - 60 s; the mold temperature is between 130 - 150°C. Preferably, the holding pressure time is 15 s.

[0118] In Step 4, the rotation speed of the injection screw is 0 - 90 revolutions per minute.

[0119] In Step 5, the cooling temperature is 45 - 75 degrees Celsius; the cooling time is at least 40 minutes. Preferably, the cooling temperature is 75 degrees Celsius.

[0120] For heat - curing molding, the heating temperature is the same as the mold curing temperature, and the time is adjusted according to the product thickness and the type of rubber used,

[0121] Specifically, the socket variable pitch plasticizing screw:

[0122] The socket variable pitch plasticizing screw is a double-layer structure, including a plasticizing screw and a cooling screw. The inside of the plasticizing screw is a hollow structure. The plasticizing screw is sleeved outside the cooling screw, and the inner diameter of the plasticizing screw is slightly larger than the outer diameter of the cooling screw.

[0123] The plasticizing screw can be divided into multiple regions along the length direction, successively including a support and sealing region, a first plasticizing region, a second plasticizing region, a third plasticizing region, and a melt guiding region.

[0124] The support and sealing region is at one end close to the driving structure of the plasticizing screw. Its surface is smooth and is connected to the drive shaft or coupling to transmit the driving force, ensuring that the plasticizing screw can smoothly receive the driving force and transmit the power to the subsequent plasticizing region part, making it rotate in the plasticizing barrel. The smooth surface of the support and sealing region also facilitates precise connection with the driving component, ensuring the stability and efficiency of power transmission. In addition, the support and sealing region can also cooperate with bearings, sealing rings or other support components to ensure that the plasticizing screw remains stable during rotation and prevent molten plastic from leaking outside the plasticizing screw. Through the close cooperation between the smooth surface and the sealing component, friction can be effectively reduced, wear can be reduced, and the service life of the equipment can be extended.

[0125] The melt guiding region is at the other end of the plasticizing screw far from the driving structure, that is, the end of the plasticizing screw, and is conical, close to the plasticizing nozzle and the injection mold. Through the conical structure, the melt guiding region increases the pressure of the plastic melt, ensuring that the melt is completely homogenized before entering the mold. At the same time, by further compressing the rubber melt, the melt guiding region can effectively eliminate bubbles and inhomogeneities in the melt, improving the quality of injection molding. In addition, the melt guiding region is directly connected to the plasticizing nozzle, controlling the flow direction of the melt and guiding the homogenized melt into the runner of the mold to ensure the smoothness of the injection process. The conical structure of the melt guiding region can reduce the flow resistance, ensuring that the melt enters the mold at a uniform speed and pressure, and avoiding product defects caused by unstable flow.

[0126] Helical lines are processed on the first plasticizing region, the second plasticizing region, and the third plasticizing region through processes such as turning, milling, grinding, and rolling forming. The shapes of the helical lines include involute shape, circular arc shape, parabolic shape, hyperbolic shape, wave shape, etc.

[0127] The first plasticizing region is located at the front of the plasticizing screw. Helical lines are processed on the first plasticizing region. The pitch of the helical line is 35 mm; the thread angle is 30°, the upper side of the trapezoidal thread cross-section is 5.5 mm, and the lower side is 18.9 mm; the proportion of the first plasticizing region in the entire plasticizing region is 25.51%.

[0128] The second plasticizing zone is located in the middle of the plasticizing screw. Helical lines are machined on the second plasticizing zone. The pitch of the helical lines is 55 mm, the thread angle is 30°, the upper side of the trapezoidal thread cross-section is 5.5 mm, and the lower side is 18.9 mm. The proportion of the second plasticizing zone in the entire plasticizing zone is 61.22%.

[0129] The third plasticizing zone is located at the rear of the plasticizing screw. Helical lines are machined on the third plasticizing zone. The pitch of the helical lines is 35 mm, the thread angle is 30°, the upper side of the trapezoidal thread cross-section is 5.5 mm, and the lower side is 18.9 mm. The proportion of the third plasticizing zone in the entire plasticizing zone is 13.27%.

[0130] The size of the pitch affects the moving speed of the rubber in the barrel and the mixing intensity, and thus affects the mixing degree of the rubber. The thread angle mainly affects the amount of rubber supplied per unit cross-section. The smaller the thread angle, the larger the amount of rubber supplied, but the screw is more likely to be worn and has a shorter lifespan.

[0131] Using a smaller pitch at the position of the helical lines near the end can increase the pressure of the rubber moving forward at the end by reducing the moving speed of the rubber, making it easier for the rubber to enter the injection barrel and also avoiding phenomena such as melt backflow at the tail end.

[0132] The cooling screw includes a spiral cooling zone, a coolant return channel, and a rotary joint. The spiral cooling zone corresponds to the plasticizing zone of the plasticizing screw and is provided with a first spiral cooling zone, a second spiral cooling zone, and a third spiral cooling zone. The rotary joint is exposed outside the internal space of the plasticizing screw. The front ends of the cooling screw and the plasticizing screw are fixed by a welding structure. The screw rotates, and the original inlet of the cooling water on the outer circle will follow the rotation. Therefore, one end of the rotary joint is connected to the rotating original inlet, and the other end is connected to the fixed external inlet of the cooling water.

[0133] A first groove that penetrates up and down along the length direction is opened on the side of the connection port between the cooling zone and the coolant return channel. One end of the first groove is connected to the starting point of the spiral-shaped groove of the spiral cooling zone. To connect the spiral cooling flow channel and the coolant return channel, its shape is a frustum of a cone, and the diameters at both ends are the same as the diameters of the corresponding flow channels.

[0134] The ratio of the diameter of the coolant spiral flow channel to the radius of the coolant return channel is When the area of the semi-circle and the full circle in the cross-section is the same, the ratio of the radius of the semi-circle to the full circle is the square root The cross-section of the spiral cooling flow channel is a semi-circle, and the cross-section of the coolant outlet flow channel is a full circle.

[0135] The spiral cooling zone is the area composed of continuous spiral grooves machined on the outer side of the cooling screw; the spiral grooves in the spiral cooling zone and the inner wall of the plasticizing screw together form a coolant flow channel;

[0136] The spiral cooling zone is the area composed of continuous spiral grooves machined on the outer side of the cooling screw; the spiral grooves in the spiral cooling zone and the inner wall of the plasticizing screw together form a coolant flow channel;

[0137] The first spiral cooling zone corresponds to the first plasticizing zone of the plasticizing screw. The spiral of the first spiral cooling zone has a linearly varying pitch along the center line. The pitch of the first section is 120 mm, and the proportion it occupies is the same as the proportion of the first plasticizing zone;

[0138] The second spiral cooling zone corresponds to the second plasticizing zone of the plasticizing screw. The spiral of the second spiral cooling zone has a linearly varying pitch along the center line. The pitch of the second section is 200 mm, and the proportion it occupies is the same as the proportion of the second plasticizing zone;

[0139] The third spiral cooling zone corresponds to the third plasticizing zone of the plasticizing screw. The spiral of the third spiral cooling zone has a linearly varying pitch along the center line. The pitch of the third section is 80 mm, and the proportion it occupies is the same as the proportion of the third plasticizing zone.

[0140] The spiral part at the end of the third spiral cooling zone is communicated with the through hole in the cooling screw arranged along the length direction;

[0141] During actual use, after the coolant flows through the spiral flow channel in the spiral cooling zone, it reaches the end of the cooling screw, enters the through hole in the cooling screw arranged along the length direction, flows along the hole, and finally flows out from the port on the side close to the coolant return channel.

[0142] Specifically, the multi-injection hole upper hot plate:

[0143] The multi-injection hole upper hot plate is a multi-level structure, mainly including an upper heat insulation plate, an upper plate temperature oil layer, a nozzle temperature oil layer, a lower plate temperature oil layer, a lower heat insulation plate, a hot plate, and a back plate from top to bottom;

[0144] The upper heat insulation plate is located above the upper plate temperature oil layer and is in direct contact with the upper plate temperature oil layer. Its main function is to insulate heat and prevent heat from conducting upward to protect the structure above the upper heat insulation plate;

[0145] The upper plate temperature oil layer is located between the upper heat insulation plate and the nozzle temperature oil layer and is in direct contact with the upper heat insulation plate and the nozzle temperature oil layer. Its main function is to conduct heat evenly to make the surface temperature of the hot plate uniform;

[0146] The chewing temperature oil layer is located between the upper plate temperature oil layer and the lower plate temperature oil layer, connecting the upper and lower temperature oil layers.

[0147] The lower plate temperature oil layer is located between the chewing temperature oil layer and the lower heat insulation plate, in direct contact with the chewing temperature oil layer and the lower heat insulation plate. Its main function is to conduct heat evenly to ensure a uniform temperature on the surface of the hot plate.

[0148] The lower heat insulation plate is located below the lower plate temperature oil layer, in direct contact with the lower plate temperature oil layer. Its main function is to insulate heat and prevent heat from conducting downward to protect the structure below the lower heat insulation plate. The upper plate temperature oil layer, the chewing temperature oil layer, and the lower plate temperature oil layer are all used to cool the flow channel (the mixed rubber in the flow channel will scorch at too high a temperature, and even directly crosslink and vulcanize to block the flow channel). Each temperature oil layer is connected to a set of cooling oil circulation systems.

[0149] The hot plate is located between the lower heat insulation plate and the back plate, generating heat through internal heating elements. It is used to heat the hot plate by electric heating or hot steam to provide heat for the products on the vulcanizing machine table, enabling the rubber products to complete the vulcanization process.

[0150] The back plate is located below the hot plate, in direct contact with the hot plate, supporting the hot plate and being tightly connected to other structural components. The back plate mainly plays a supporting role to maintain the stability and strength of the entire structure.

[0151] Multiple injection nozzles are provided on the back plate. The upper end of the injection nozzle is connected to the upper heat insulation plate. Rubber enters the cavity of the nozzle through the injection flow channel. The cavity is directly connected to the upper and lower temperature oil layers and the chewing temperature oil layer to reduce the internal rubber temperature and avoid scorching or blocking the nozzle with old rubber. There is a gap between the lower half of the nozzle and the lower heat insulation plate and the hot plate to avoid direct contact with the hot plate and causing too high an internal rubber temperature. The back plate nozzle has a double-layer heat insulation design. An air gap is made between the outer layer and the inner layer to reduce the direct contact area between the nozzle and the back plate and slow down the heating rate of the nozzle tail end temperature, so as to reduce the scorching and aging rate of the rubber at the corresponding position (this position must have a contact assembly relationship with the back plate to avoid nozzle loosening and deformation, and the internal rubber needs to be emptied by punching the material head before each injection).

[0152] The injection nozzles on the back plate are divided into 3 groups, with 4 nozzles in each group. Taking the center of the rectangle as the coordinate origin, the coordinates of the four injection nozzles in the first group are (550, 550), (-550, 550), (-550, -550), and (550, -550); the coordinates of the four injection nozzles in the second group are (550, 0), (0, 550), (-550, 0), and (0, -550); the coordinates of the four injection nozzles in the third group are (350, 200), (-350, 200), (-350, -200), and (350, -200). To ensure that the glue ejection pressure from the four holes is similar, generally, the injection nozzles in the same group are used for injection simultaneously. For special products such as asymmetric shaped parts, asymmetric four holes or fewer than four injection holes can be considered for injection, but the injection speed needs to be adjusted to avoid abnormal product quality.

[0153] The positions of the injection holes are based on the current hot plate size. If other hot plates are used or there are special product requirements, the positions and quantities of the injection nozzles are adjusted accordingly according to actual needs.

[0154] An injection cavity is provided corresponding to each injection nozzle. The injection cavity penetrates through the nozzle temperature oil layer, the lower plate temperature oil layer, the lower heat insulation plate, the hot plate, and the back plate, and is communicated with the outside through the injection nozzle;

[0155] An injection flow channel communicating the plasticizing barrel and the injection cavity is provided in the nozzle temperature oil layer. The plasticized rubber enters the injection cavity from the plasticizing barrel through the injection flow channel;

[0156] Cold flow channels are provided around the injection cavity in the upper plate temperature oil layer and the lower plate temperature oil layer. Coolant flows through the cold flow channels to control the temperature of the plasticized rubber entering the injection cavity;

[0157] A solenoid valve is inlaid in the back plate near the injection nozzle. The solenoid valve can be switched in the back plate, and the solenoid valve plug in it can block the injection nozzle to control the number of injection nozzles for injection operation;

[0158] In a specific embodiment, when only several of the injection nozzles are needed for injection operation, the solenoid valve is started to close the other injection nozzles that are not needed. The rubber plasticized by the plasticizing barrel enters the injection cavity through the injection flow channel, and then is injected into the mold through the injection nozzle.

[0159] Specifically, the electric control screw temperature control device:

[0160] The electric control screw temperature control device includes components such as a device housing, a PLC control motor, a planetary reducer, a drive shaft, a drive gear, a driven gear, a positioning ring, a solid pin, and a hollow pin.

[0161] The described electric control screw temperature control device includes one or more, generally circular in shape, and sleeved outside the plasticizing barrel;

[0162] The device housing is fixed on the plasticizing barrel housing through bolts and / or brackets, wrapping the internal components to protect the internal components from the influence of the external environment on the device;

[0163] The PLC control motor is installed above the device housing; a motor support plate is also fixedly arranged on the PLC control motor, and the motor support plate is fixed on the device housing through bolts to provide a stable support platform for the PLC control motor; the motor support plate can support and fix the PLC control motor, absorb vibration, and ensure the stability of the motor during operation;

[0164] The output end of the PLC control motor is connected to the planetary reducer, the input shaft of the planetary reducer is connected to the output shaft of the PLC control motor through a coupling, and the body of the planetary reducer is fixed on the motor support plate or other fixed brackets through bolts;

[0165] The output end of the planetary reducer is connected to the drive shaft, and the drive shaft passes through the device housing and the positioning ring arranged inside the device housing from outside the device housing, extends into the device housing, and is connected to the drive gear at the end;

[0166] After the output speed of the PLC control motor is adjusted by the planetary reducer, the drive gear is driven to rotate via the drive shaft;

[0167] A plurality of driven gears are arranged on both sides of the drive gear, and the drive gear and the driven gears or the driven gears are meshed in sequence; the drive gear or the driven gears are helical bevel gears;

[0168] The gear rim of the helical bevel gear is conical, and the tooth line is inclined relative to the gear axis and can be meshed with another gear of a similar shape; due to the inclination of the tooth line relative to the gear axis, the contact area of gear meshing is increased, thereby improving the transmission smoothness and load capacity; it has high power transmission capacity during the transmission process and can withstand a large torque, realizing the steering and transmission of power between the drive gear and the driven gears or the driven gears. A plurality of bevel gears are meshed to form a quasi-circular structure, and the included angle of the bevel gears is less than 90°, for example, bevel gears with an included angle of 45° or 30° can be used.

[0169] In a specific embodiment, the extension lines of the gear rims of each of the driving gears or the driven gears intersect at the center of the electric control screw temperature control device, and the corresponding rectangular central angle is approximately 30°; five driven gears connected in sequence are respectively arranged on both sides of the driving gear, and the driving gear and the driven gears approximately form an unclosed circle.

[0170] The positioning ring is arranged inside the device housing and is concentric with the device housing; on the multiple driven gears on both sides of the driving gear, hollow pins and solid pins are sequentially arranged, and the hollow pins and the solid pins are arranged at intervals; the included angle between the driving shaft and two adjacent hollow pins is approximately 30°, and the included angle between two adjacent hollow pins and the solid pins is approximately 30°;

[0171] One end of the solid pin is rotatably connected to the positioning ring, and the other end is fixedly connected to the driven gear as the driving shaft of the driven gear; the hollow pin includes a hollow rotating shaft sleeve, a driven temperature control shaft, and a temperature control head. One end of the hollow rotating shaft sleeve of the hollow pin is rotatably connected to the positioning ring, and the other end passes through the axis of the driven gear and is inserted into the plasticizing barrel all the way. A thread is arranged between the driven temperature control shaft and the temperature control head, and can be screwed in and out on the wall of the plasticizing barrel to change the insertion depth of the temperature control head in the plasticizing barrel; a temperature sensor is arranged on the temperature control head to be able to monitor the rubber temperature in the plasticizing barrel in real time.

[0172] In the specific implementation process, when the temperature control head detects that the rubber temperature in the plasticizing barrel fails to reach the preset temperature, the PLC control motor is started. The output shaft of the motor rotates, the planetary reducer adjusts the rotation speed output by the output shaft of the motor, and drives the driving gear to rotate through the driving shaft. The driving gear drives the driven gears to rotate, and the hollow pins fixedly connected to several of the driven gears are screwed into the interior of the plasticizing barrel. Specifically, when the temperature control head is partially inserted into the spiral line position of the plasticizing screw, it is equivalent to encrypting the spiral line. After the spiral line is encrypted, the contact area between the screw and the rubber increases. At the same time, the flow path of the rubber inside the screw becomes shorter, the flow rate increases, the flow resistance increases, the internal pressure rises, and the shear force received by the rubber also increases;

[0173] When the temperature control head detects that the temperature of the rubber in the plasticizing barrel exceeds the preset temperature, the PLC control motor is started, the output shaft of the motor rotates in the reverse direction, the planetary reducer adjusts the rotational speed output by the output shaft of the motor, and drives the driving gear to rotate in the reverse direction through the drive shaft. The driving gear drives the driven gear to rotate in the reverse direction, and the hollow pins fixedly connected to several of the driven gears are screwed out of the inside of the plasticizing barrel. Specifically, when the temperature control head is partially pulled out from the helical position of the plasticizing screw, it is equivalent to reducing the density of the helix. After the helix density is reduced, the contact area between the screw and the rubber decreases, and at the same time, the flow path of the rubber inside the screw becomes longer, the flow rate decreases, the flow resistance decreases, the internal pressure decreases, and the shear force on the rubber decreases.

[0174] Specifically, the mold precise positioning device (including the electric control sliding positioning device and the positioning displacement plate):

[0175] The electric control sliding positioning device includes a PLC motor, a driving gear, a plurality of driven supporting gears, a double-sided rack, a positioning slider, an electronic scale, a tail-end baffle, and a hydraulic lifting device;

[0176] The PLC motor is fixedly connected to the driving gear and can drive the driving gear to rotate;

[0177] A plurality of the driven supporting gears are in a pair up and down, forming multiple pairs of driven gear groups, which are arranged on the gear bracket and can rotate on the gear bracket;

[0178] The centers of the plurality of driven supporting gears located below and the center of the driving gear are on a straight line, the centers of the plurality of driven supporting gears located above are on a straight line, and the two straight lines are parallel to the movement direction of the double-sided rack;

[0179] The double-sided rack is arranged between the upper and lower driven supporting gears of multiple pairs of the driven gear groups and above the driving gear;

[0180] The teeth on the double-sided rack match the teeth of the driving gear and / or the driven supporting gears and are in contact and engagement with the driven supporting gears and / or the driving gear; the double-sided rack can move back and forth along the length direction of the double-sided rack under the drive of the driving gear and / or the driven supporting gears.

[0181] A positioning slider is arranged at the front end of the double-sided rack, and the front end of the positioning slider can be set in shapes such as a semi-circular arc, a square, a triangle, etc.; a positioning head is arranged on the upper part of the positioning slider, and the shape and size of the positioning head can match the mold positioning groove arranged at the bottom edge of the mold;

[0182] The electronic ruler is fixedly arranged on the side of the double-sided rack and is used to measure the moving distance of the double-sided rack;

[0183] The end baffle is arranged at the outer end of the moving path of the double-sided rack, which is far away from the positioning slider side, to prevent the double-sided rack and / or the positioning slider from exceeding the stroke range and ensure safety;

[0184] The PLC motor, the gear bracket, and the end baffle are all fixedly arranged on the upper plane of the hydraulic lifting bracket. The lower plane of the hydraulic lifting bracket is connected to the hydraulic lifting device, and the height can be changed through the hydraulic lifting device, so as to drive the PLC motor, the gear bracket, and the end baffle fixed above the hydraulic lifting bracket to move up and down accordingly;

[0185] The electric control sliding positioning device is used in cooperation with the belt positioning moving plate. The belt positioning moving plate is a flat plate with a sufficient length for mold positioning and is used to position the injection mold; grooves for ensuring that all molds can be positioned to the injection position are opened on the upper surface of the belt positioning moving plate from the edge to the inside at both sides. The innermost end of the groove can be set as a semi-circular arc, a square or a triangle, which is matched with the top shape of the positioning slider. The positioning slider can slide in the groove driven by the double-sided rack; the belt positioning moving plate is 1600mm x 1800mm; the groove length is 600mm, the width is 58.8mm, and the depth is 25mm.

[0186] During actual use, the mold positioning process includes the following steps:

[0187] The belt positioning moving plate is located between two or more of the electric control sliding positioning devices;

[0188] Before placing the mold, the height of the positioning slider is the same as the height of the groove on the belt positioning moving plate, and it is located at the entrance of the groove, in the initial position. The PLC motor is in the standby state, ready to receive the control signal;

[0189] After the PLC motor receives the start signal, it starts to operate, the driving gear starts to rotate, meshes with the teeth on the double-sided rack one by one, and drives the double-sided rack to start moving; the positioning slider moves synchronously with the movement of the double-sided rack, and the initial position of the positioning slider is recorded by the electronic ruler;

[0190] Place the mold on the belt positioning moving plate. There is a mold groove on the mold, which is matched with the shape and size of the positioning head on the positioning slider; the positioning slider moves continuously with the movement of the double-sided rack. During this process, the electronic ruler continuously measures the position of the positioning slider and feeds the data back to the PLC motor to ensure that the positioning slider moves accurately to the specified position. The driving gear and the driven gear set work together to ensure the smooth movement of the positioning slider;

[0191] When the positioning slider moves to the mold groove, the PLC motor stops rotating after receiving the position information fed back by the electronic ruler; the positioning slider stops precisely at the designated position, completing the positioning operation;

[0192] After the positioning is completed, the PLC motor rotates in the reverse direction, driving the positioning slider to move in the reverse direction back to the initial position, and the hydraulic lifting device lifts the hydraulic lifting bracket to directly move the positioning slider and / or the double-sided rack upward out of the groove on the belt positioning shift plate;

[0193] Furthermore, the positioning plate with a movable plate and the mold thereon are automatically sent between the upper hot plate and the lower hot plate through structures such as rails, and the upper and lower hot plates are pressed tightly, and the injection step is mainly completed by the injection cylinder. After the injection is completed, the mold and the positioning plate with a movable plate are sent back between two or more of the electrically controlled sliding positioning devices, and the hydraulic lifting bracket moves downward under the action of the hydraulic lifting device, and the positioning slider is back to its initial position; the PLC motor stops rotating, and the system enters a standby state, waiting for the next start signal.

[0194] The protection content of the present invention is not limited to the above embodiments. Without departing from the spirit and scope of the present invention, changes and advantages that can be thought of by those skilled in the art are included in the present invention and are protected by the attached claims.

Claims

1. A socket variable pitch plasticizing screw for an injection molding machine, characterized in that, The socket variable pitch plasticizing screw is a double-layer structure, including a plasticizing screw and a cooling screw. The inside of the plasticizing screw is a hollow structure. The plasticizing screw is sleeved outside the cooling screw, and the inner diameter of the plasticizing screw is larger than the outer diameter of the cooling screw. The plasticizing screw is divided into multiple regions along the length direction, successively including a support sealing region, a plasticizing region, and a melt guiding region. The plasticizing region includes: a first plasticizing region, a second plasticizing region, and a third plasticizing region. The cooling screw includes a spiral cooling region, a coolant return channel, and a rotary joint.

2. The variable pitch plasticizing screw sleeve according to claim 1, characterized in that, On the first plasticizing region, the second plasticizing region, and the third plasticizing region, spiral lines are provided, and the corners are rounded. The shape of the spiral line is an involute shape, an arc shape, a parabola shape, a hyperbola shape, or a waveform shape.

3. The sleeved variable pitch plasticizing screw according to claim 1, characterized in that, The first plasticizing region is located at the front of the plasticizing screw. Spiral lines are machined on the first plasticizing region. The pitch range of the spiral lines is 30 - 35 mm; the thread angle is 30°, the upper side of the trapezoidal thread section is 5.5 mm, and the lower side is 18.9 mm; the proportion of the first plasticizing region in the entire plasticizing region is 25.51%. The second plasticizing region is located in the middle of the plasticizing screw. Spiral lines are machined on the second plasticizing region. The pitch range of the spiral lines is 50 - 55 mm, the thread angle is 30°, the upper side of the trapezoidal thread section is 5.5 mm, and the lower side is 18.9 mm; the proportion of the second plasticizing region in the entire plasticizing region is 61.22%. The third plasticizing region is located at the rear of the plasticizing screw. Spiral lines are machined on the third plasticizing region. The pitch range of the spiral lines is 30 - 35 mm, the thread angle is 30°, the upper side of the trapezoidal thread section is 5.5 mm, and the lower side is 18.9 mm; the proportion of the third plasticizing region in the entire plasticizing region is 13.27%.

4. The socket variable pitch plasticizing screw according to claim 2 or 3, characterized in that, The pitch of the spiral line in the first plasticizing region is 35 mm. and / or The pitch of the spiral line in the second plasticizing region is 55 mm. and / or The pitch of the spiral line in the third plasticizing region is 35 mm.

5. The sleeved variable pitch plasticizing screw according to claim 1, characterized in that, The support sealing region is at one end close to the driving structure of the plasticizing screw, with a smooth surface, connected to the driving shaft or coupling to transmit the driving force. The melt guiding region is at the other end of the plasticizing screw away from the driving structure, that is, the end of the plasticizing screw, and is conical. The melt guiding region increases the pressure of the rubber melt through the conical structure to ensure that the melt is completely homogenized before entering the mold and increases the pressure entering the injection barrel.

6. The variable pitch plasticizing screw sleeve according to claim 1, wherein, The spiral cooling region corresponds to the plasticizing region of the plasticizing screw, and is provided with a first spiral cooling region, a second spiral cooling region, and a third spiral cooling region. The rotary joint is exposed outside the plasticizing screw. One end of the rotary joint is connected to the original rotating inlet, and the other end is connected to the fixed cooling water inlet and cooling water outlet. The front ends of the cooling screw and the plasticizing screw are fixed by a welding structure.

7. The sleeve variable pitch plasticizing screw according to claim 6, wherein, A first groove that penetrates up and down is formed along the length direction on the side of the connection port between the cooling zone and the coolant return channel. One end of the first groove is connected to the starting point of the spiral groove in the spiral cooling zone. To connect the spiral cooling flow channel and the coolant return channel, its shape is a frustum of a cone, and the diameters at both ends are equal to the diameters of the corresponding flow channels; the ratio of the diameter of the coolant spiral flow channel to the radius of the coolant return channel is 8. The variable pitch plasticizing screw sleeve according to claim 6, wherein, The spiral cooling region is a region composed of continuously spiral grooves machined on the outside of the cooling screw. The spiral grooves in the spiral cooling region and the inner wall of the plasticizing screw together form a flow channel for the coolant.

9. The sleeved variable pitch plasticizing screw according to claim 6, wherein, The first spiral cooling zone corresponds to the first plasticizing zone of the plasticizing screw. The spiral of the first spiral cooling zone is a linearly variable pitch along the center line. The pitch of the first section is 120 mm, and the proportion it occupies is equal to the proportion of the first plasticizing zone. The second spiral cooling zone corresponds to the second plasticizing zone of the plasticizing screw. The spiral of the second spiral cooling zone is a linearly variable pitch along the center line. The pitch of the second section is 200 mm, and the proportion it occupies is equal to the proportion of the second plasticizing zone. The third spiral cooling zone corresponds to the third plasticizing zone of the plasticizing screw. The spiral of the third spiral cooling zone is a linearly variable pitch along the center line. The pitch of the third section is 80 mm, and the proportion it occupies is equal to the proportion of the third plasticizing zone.

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