An integrated injection mold for anti-displacement TPR caster wheel core

Abstract

This invention discloses an integrated injection mold for anti-misalignment TPR caster cores, belonging to the field of injection mold technology. It includes a mold base and mold feet symmetrically fixed on both sides of the top of the mold base. This invention achieves precise coaxial calibration of the upper and lower mold cores during the initial mold closing stage by engaging a limiting sleeve coaxially set at the top of the lower mold core and a limiting rod coaxially fixed at the bottom of the upper mold core. Simultaneously, a flexible, movable plate at the lower mold core can both axially push the molded product for initial demolding during the mold opening stage and link with a vibration mechanism during the mold closing stage. The axial movement of the limiting rod inserting into the limiting sleeve during mold closing generates continuous up-and-down vibration, which is synchronously transmitted to the plate and the limiting sleeve. This effectively eliminates the jamming between the burrs, flash, parting line protrusions, and the limiting structure on the inner wall of the inner shaft hole of the wheel core, ensuring smooth installation of the wheel core insert and further eliminating initial positioning deviations of the insert.

Description

Technical Field

[0001] This invention relates to an integrated injection mold, and more particularly to an integrated injection mold for an anti-displacement TPR caster core, belonging to the field of injection mold technology. Background Technology

[0002] The core structure of TPR casters is a composite structure of a rigid plastic wheel core frame and an outer TPR coating layer. The mainstream industry practice for this type of product is to use an insert-type integrated injection molding process, in which the rigid wheel core frame is pre-molded as an insert, pre-installed into the injection mold, and then the TPR coating layer is integrated and molded in one injection molding process. This is the mainstream molding solution in the industry.

[0003] However, in the current use of this type of insert mold, the outer diameter of the lower mold core limiting rod is designed to be smaller than the inner diameter of the inner shaft hole of the wheel core in order to reserve assembly clearance. However, during production, the inner wall of the inner shaft hole of the wheel core is prone to molding defects such as injection flash, parting line protrusion, and burrs. During the pre-assembly of the insert, the burrs on the inner wall are very likely to get stuck with the limiting rod. This can lead to problems such as the wheel core insert not being able to be smoothly installed, resulting in end face tilting and axial positioning inaccuracy. In addition, in order to avoid the inner ring of the wheel hub and the mold core scraping and getting stuck when the wheel core insert is installed, an assembly clearance is also reserved between the mold core and the inner ring of the wheel hub. This clearance and the fit clearance of the limiting rod form a double clearance error, which further amplifies the initial positioning deviation of the wheel core insert and affects the injection molding effect.

[0004] To address this issue, an integrated injection mold for anti-displacement TPR caster wheel core was designed. Summary of the Invention

[0005] The main objective of this invention is to provide an integrated injection mold for anti-displacement TPR caster cores, in order to solve the problems of jamming between the core insert and the limiting structure during pre-assembly, and the inability to stably limit the position due to the assembly gap between the mold core and the core insert after pre-assembly.

[0006] The objective of this invention can be achieved by adopting the following technical solution: An anti-displacement TPR caster core integrated injection mold includes a mold base, mold feet symmetrically fixed on both sides of the top of the mold base, a lower mold fixedly installed on the top of the mold feet, an upper mold that can open and close with the lower mold in the vertical direction, and an ejection mechanism between the mold base and the lower mold. The top of the lower mold has several sets of lower mold cores arranged in a rectangular array. A plate is slidably mounted on the top of the lower mold core in the vertical direction. A first spring is installed between the bottom surface of the plate and the top surface of the lower mold core. A limit sleeve is coaxially fixed at the center of the plate. The bottom of the upper mold is fixed with an upper mold core that corresponds one-to-one with the lower mold core and is coaxially fitted. The bottom of the upper mold core is coaxially fixed with a limiting rod that is properly fitted to the limiting sleeve. A shaking mechanism is provided between the bottom outer wall of the limiting rod and the inner wall of the limiting sleeve. The shaking mechanism is used to drive the limiting sleeve and the plate to shake in the vertical direction during the process of the limiting rod being axially inserted into the limiting sleeve. The lower mold core is equipped with a positioning mechanism for radially pressing and limiting the inner ring of the wheel hub insert. The drive end of the positioning mechanism cooperates with the bottom end of the limiting rod, so that the limiting action of the positioning mechanism is linked with the insertion action of the limiting rod.

[0007] Preferably, the top four corners of the lower mold are fixed with guide pillars, and the bottom four corners of the upper mold are provided with slots that correspond to and are adapted to the guide pillars. The guide pillars and guide slots cooperate to form a guiding and positioning structure for mold opening and closing.

[0008] Preferably, the ejection mechanism includes a mounting plate, a fixing column, a return spring, and an ejector pin; The mounting plate is slidably positioned between the two sets of mold feet in a vertical direction. The fixing post is fixed to the top of the mounting plate. The return spring is sleeved on the outside of the fixing post, and the two ends of the return spring abut against the top surface of the mounting plate and the bottom surface of the lower mold, respectively. The ejector pin and the lower mold core are fixed to the top of the mounting plate one by one. The top of the ejector pin passes through the lower mold, the lower mold core and the mounting plate. A hole is opened in the middle of the mold base for the cylinder output end to pass through.

[0009] Preferably, the vibration mechanism includes a slide, a ball, a second spring, a positioning bolt, and an annular toothed groove; The annular toothed grooves are coaxially formed on the inner wall of the limiting sleeve, and multiple sets of annular toothed grooves are continuously arranged along the axial direction of the limiting sleeve. A groove is radially formed on the bottom side wall of the limiting rod. A second spring is located inside the groove. A ball is slidably positioned at the opening end of the groove, and the opening end of the groove has an arc-shaped constriction structure that matches the ball. The inner end face of the ball abuts against the outer end of the second spring. The outer spherical surface of the ball meshes with the annular tooth groove. A positioning bolt is threadedly connected to the bottom end of the limiting rod and extends to the inner end of the groove. The inner end of the second spring abuts against the outer side of the positioning bolt.

[0010] Preferably, the positioning mechanism includes a lower groove, a sector-shaped slider, a push rod, a third spring, a push block, and an inclined guide surface; The lower groove is coaxially opened at the top center of the lower mold core. Multiple sets of fan-shaped sliders are evenly slidably arranged inside the lower groove along the circumferential direction. The inner top of the fan-shaped sliders is provided with an inclined guide surface, which is squeezed and matched with the bottom end of the limiting rod. The push rod is fixed radially to the outer wall of the fan-shaped slider. The outer end of the push rod extends to the outer side of the lower mold core and is fixedly connected to the push block. The third spring is sleeved on the outer side of the push rod, and the two ends of the third spring abut against the outer wall of the fan-shaped slider and the inner wall of the lower groove, respectively.

[0011] Preferably, the bottom end of the limiting rod is provided with a tapered guide head, and the taper of the tapered guide head is adapted to the taper of the inclined guide surface.

[0012] Preferably, the side wall of the lower mold core is provided with guide through holes that are coaxially adapted to the push rods, and the outer end of the guide through holes is provided with hidden grooves adapted to the push blocks.

[0013] Preferably, the outer shape of the push block is adapted to the inner ring shape of the wheel hub insert, and the outer side of the push block is provided with anti-slip texture to prevent the wheel hub insert from rotating circumferentially.

[0014] Preferably, there are four push blocks on the outer side of the lower mold core, and the included angle between adjacent push blocks is 90°.

[0015] Preferably, the top of the lower mold core is provided with an upper groove, the first spring is disposed inside the upper groove, the inner top of the upper groove is integrally provided with a limiting flange that limits the vertical sliding stroke of the plate, and the outer side of the top of the plate is provided with a stepped groove that cooperates with the limiting flange.

[0016] The beneficial effects of this invention are as follows: This invention provides an integrated injection mold for anti-misalignment TPR caster cores. By engaging a limiting sleeve coaxially set at the top of the lower mold core and a limiting rod coaxially fixed at the bottom of the upper mold core, the coaxiality of the upper and lower mold cores is precisely calibrated at the initial stage of mold closing. This eliminates cavity misalignment caused by the misalignment of the moving and fixed molds from the source of mold closing, provides a stable coaxial reference for the positioning of the core insert, achieves initial anti-misalignment, and ensures the long-term stability of the mold closing accuracy. The flexible plate at the lower mold core can both push the molded product axially for initial demolding during the mold opening stage and link with the vibration mechanism consisting of the bottom groove of the limit rod, ball bearings, second spring, positioning bolt, and the annular toothed groove inside the limit sleeve during the mold closing stage. By using the axial movement of the limit rod inserting into the limit sleeve during the mold closing process, the continuous engagement and disengagement of the ball bearings and the annular toothed groove generate continuous up-and-down vibration, and transmit the vibration force synchronously to the plate and the limit sleeve. This effectively eliminates the jamming between the burrs, flash, parting line protrusions on the inner wall of the wheel core shaft hole and the limit structure, ensuring that the wheel core insert can be smoothly installed and further eliminating the initial positioning deviation of the insert. By setting an internal support positioning mechanism at the bottom of the lower mold core, consisting of a lower groove, a fan-shaped slider, a push rod, a third spring, a push block, and an inclined guide surface, a purely mechanical linkage that is time-matched with the mold closing action can be formed. During the mold closing process, after the shaking mechanism completes the smooth placement of the wheel core insert, the continuous axial insertion action of the limiting rod drives the inclined guide surface of the fan-shaped slider to push multiple sets of circumferentially distributed push rods and push blocks to expand radially outward through the extrusion of the limiting rod. This allows the push block to achieve a full-circumferential gapless fit with the inner ring of the wheel core and hub, completely limiting and fixing the wheel core. This eliminates the double assembly gaps between the limiting sleeve and the inner shaft hole, and between the mold core and the inner ring of the hub, ensuring the uniformity of the overmolding layer wall thickness and the overall coaxiality of the wheel core, thus ensuring the quality of injection molding. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall front view of the present invention; Figure 2 This is a top view of the initial state of the top of the lower mold of the present invention; Figure 3 This is a schematic diagram of the bottom structure of the upper mold of the present invention; Figure 4 This is a schematic diagram of the injection molding state of the top of the lower mold of the present invention; Figure 5 This is a schematic cross-sectional view of the lower mold in its initial state according to the present invention; Figure 6 This is a schematic cross-sectional view of the lower mold in the mold-closing state of the present invention; Figure 7 This is a side view of the lower mold of the present invention; Figure 8 This is a cross-sectional view of the lower mold core in its initial state according to the present invention; Figure 9 This is a cross-sectional view of the lower mold core in the mold-closing state according to the present invention; Figure 10 This is a cross-sectional view of the bottom structure of the limiting rod of the present invention.

[0018] In the diagram: 1. Mold base; 2. Mold foot; 3. Lower mold; 301 guide pillars; 4. Ejection mechanism; 401. Mounting plate; 402. Fixing column; 403. Return spring; 404. Ejector pin; 5. Upper mold; 501. Guide groove; 6. Lower mold core; 7. Panel; 701, stepped groove; 8. Limit sleeve; 9. Upper mold core; 10. Limiting rod; 11. Upper groove; 1101. Limiting flange; 12. The first spring; 13. Vibration mechanism; 1301. Slide groove; 1302. Ball bearing; 1303. Second spring; 1304. Positioning bolt; 1305. Annular toothed groove; 14. Positioning mechanism; 1401. Lower groove; 1402. Fan-shaped slider; 1403. Push rod; 1404. Third spring; 1405. Push block; 1406. Inclined guide surface. Detailed Implementation

[0019] To enable those skilled in the art to more clearly understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0020] Example 1 like Figures 1-10 As shown, this embodiment provides an integrated injection mold for anti-displacement TPR caster core, including a mold base 1, mold feet 2 symmetrically fixed on both sides of the top of the mold base 1, a lower mold 3 fixedly installed on the top of the mold feet 2, an upper mold 5 that can open and close with the lower mold 3 in the vertical direction, and an ejection mechanism 4 between the mold base 1 and the lower mold 3. The top of the lower mold 3 has several sets of lower mold cores 6 arranged in a rectangular array. The top of the lower mold core 6 is slidably provided with a plate 7 in the vertical direction. The plate 7 initially protrudes from the top of the lower mold core 6, but is pressed down to be level with the top of the lower mold core 6 during the injection molding process. A first spring 12 is provided between the bottom surface of the plate 7 and the top surface of the lower mold core 6. A limit sleeve 8 is coaxially fixed at the center of the plate 7. The bottom of the upper mold 5 is fixed with an upper mold core 9 that corresponds one-to-one with the lower mold core 6 and is coaxially fitted. The bottom of the upper mold core 9 is coaxially fixed with a limiting rod 10 that fits into the limiting sleeve 8. A shaking mechanism 13 is provided between the bottom outer wall of the limiting rod 10 and the inner wall of the limiting sleeve 8. The shaking mechanism 13 is used to drive the limiting sleeve 8 and the plate 7 to shake in the vertical direction during the process of the limiting rod 10 being axially inserted into the limiting sleeve 8. The lower mold core 6 is provided with a positioning mechanism 14 for radially pressing and limiting the inner ring of the wheel hub insert. The driving end of the positioning mechanism 14 cooperates with the bottom end of the limiting rod 10, so that the limiting action of the positioning mechanism 14 is linked with the insertion action of the limiting rod 10.

[0021] Initial mold opening state: The upper mold 5 and the lower mold 3 are in a completely separated mold opening state, the ejection mechanism 4 is in the downward reset position, the plate 7 is in the upper limit position under the elastic support of the first spring 12, the limiting sleeve 8 is in the upper limit position synchronously with the plate 7, and the positioning mechanism 14 is in the initial radial retraction state without any outward limiting action; at this time, the operator or robot arm will use the pre-injection molded hard wheel core frame as an insert, and coaxially install it on the outside of the limiting sleeve 8. The bottom surface of the wheel core insert is supported on the top surface of the plate 7, completing the pre-installation preparation.

[0022] Mold closing linkage action: The injection molding machine drives the upper mold 5 to close vertically downwards, and the upper mold core 9 moves down synchronously with the upper mold 5. The limiting rod 10 first inserts into the inner hole of the limiting sleeve 8 to complete the pre-calibration of the coaxiality of the upper mold core 9 and the lower mold core 6, eliminating the cavity deviation caused by the mold closing misalignment. During the process of the limiting rod 10 continuously inserting into the limiting sleeve 8, the vibration mechanism 13 is triggered, driving the limiting sleeve 8 and the plate 7 to generate continuous vibration in the vertical direction. The vibration force breaks the burrs, flash, and mold closing line protrusions on the inner wall of the inner shaft hole of the wheel core insert and the jam between the limiting sleeve 8, so that the wheel core insert falls smoothly to the preset pre-installed position, solving the problem of end face tilting and axial positioning inaccuracy caused by insert jamming, and eliminating the initial positioning deviation.

[0023] Positioning and locking action: After the limiting rod 10 completes the shaking and positioning action, it continues to move down with the upper mold core 9. The upper mold core 9 continues to move down and press down on the wheel core. The bottom of the wheel core presses down the plate 7 to a position flush with the top of the lower mold core 6. At the same time, the limiting rod 10 inserts into the positioning mechanism 14 inside the lower mold core 6, driving the positioning mechanism 14 to expand radially outward in sync. This makes the limiting end of the positioning mechanism 14 completely fit with the inner ring of the wheel core insert, achieving full-circumference rigid limiting. This eliminates the double assembly gap between the limiting sleeve 8 and the inner shaft hole of the wheel core, and between the lower mold core 6 and the inner ring of the wheel core, solving the misalignment risk caused by the enlargement of the initial positioning gap. At the same time, it resists the lateral impact force of the material flow during the subsequent injection molding process, achieving the anti-misalignment effect throughout the injection molding process.

[0024] Injection molding process: The upper mold 5 and the lower mold 3 are fully closed, and the upper mold core 9 and the lower mold core 6 are closed to form a closed TPR overmolding cavity. The injection molding machine injects molten TPR material into the cavity to complete the integrated injection molding of the wheel core overmolding layer. During the holding pressure process, the positioning mechanism 14 always maintains a rigid limit on the wheel core insert to prevent the wheel core from being radially deflected or axially moved due to the impact of asymmetrical material flow, and to ensure the uniformity of the overmolding layer wall thickness and the overall coaxiality of the wheel core.

[0025] Mold opening and reset action: After injection molding, holding pressure and cooling are completed, the injection molding machine drives the upper mold 5 to open vertically upward. The limit rod 10 moves upward synchronously with the upper mold core 9 and is pulled out from the positioning mechanism 14. After the positioning mechanism 14 loses driving force, it automatically retracts radially and releases the limit on the wheel core product. At the same time, the plate 7 resets upward under the action of the first spring 12 and initially ejects the product. Then, the limit rod 10 is completely pulled out from the limit sleeve 8. After the upper mold 5 and the lower mold 3 are completely separated, the ejection mechanism 4 moves upward and completely ejects the molded wheel core product from the lower mold core 6 to demold, completing a single injection molding cycle.

[0026] Example 2 The solution in Example 1 will be further described below with reference to its specific working method. In this embodiment, guide posts 301 are fixed at the top four corners of the lower mold 3, and slots 501 corresponding to and adapted to the guide posts 301 are opened at the bottom four corners of the upper mold 5. The guide posts 301 and the guide slots 501 cooperate to form a guiding and positioning structure for mold opening and closing.

[0027] During the mold opening and closing process, when the upper mold 5 moves downward to close, the guide post 301 is inserted into the corresponding guide groove 501 first. Through the gap fit between the guide post 301 and the guide groove 501, the overall rough positioning of the upper mold 5 and the lower mold 3 and the guidance of the entire mold opening and closing process are completed, which restricts the horizontal movement and deflection of the upper mold 5 and ensures the overall parallelism of the upper mold 5 and the lower mold 3 when they are closed.

[0028] In this embodiment, the ejection mechanism 4 includes a mounting plate 401, a fixing post 402, a return spring 403, and an ejector pin 404; Mounting plate 401 is slidably disposed between two sets of mold feet 2 in a vertical direction. Fixing post 402 is fixed to the top of mounting plate 401. Return spring 403 is sleeved on the outside of fixing post 402, and the two ends of return spring 403 abut against the top surface of mounting plate 401 and the bottom surface of lower mold 3, respectively. Ejector pin 404 and lower mold core 6 are fixed to the top of mounting plate 401 in a one-to-one correspondence. The top end of ejector pin 404 penetrates the lower mold 3, lower mold core 6 and mounting plate 7. A hole for the cylinder output end to pass through is opened in the middle position of mold base 1.

[0029] During the mold opening and ejection stage, the output end of the ejection cylinder of the injection molding machine passes through the hole of the mold base 1 and pushes the mounting plate 401 upward in the vertical direction. The mounting plate 401 drives all the ejector pins 404 to slide upward synchronously. The top of the ejector pins 404 pushes the plate 7 upward, smoothly ejecting the molded wheel core product and demolding it. After the ejection action is completed, the output end of the cylinder retracts downward. Under the elastic force of the return spring 403, the mounting plate 401 drives the ejector pins 404 to move downward synchronously to reset. Under the action of the first spring 12, the plate 7 falls back to the initial position synchronously, preparing for the next injection cycle.

[0030] In this embodiment, the shaking mechanism 13 includes a slide groove 1301, a ball bearing 1302, a second spring 1303, a positioning bolt 1304, and an annular toothed groove 1305; The annular toothed groove 1305 is coaxially formed on the inner wall of the limiting sleeve 8, and multiple sets of the annular toothed groove 1305 are continuously arranged along the axial direction of the limiting sleeve 8. A groove 1301 is radially formed on the bottom side wall of the limiting rod 10. A second spring 1303 is disposed inside the groove 1301. A ball 1302 is slidably disposed at the open end of the groove 1301. The open end of the groove 1301 is an arc-shaped constriction structure adapted to the ball 1302 to restrict the ball 1302 from coming out, ensuring that the ball 1302 can only slide radially along the groove 1301, thus preventing the ball 1302 from falling off and failing during vibration. The inner end face of the ball 1302 abuts against the outer end of the second spring 1303. The outer spherical surface of the ball 1302 meshes with the annular toothed groove 1305. A positioning bolt 1304 is threadedly connected to the bottom end of the limiting rod 10 and extends to the inner end of the groove 1301. The inner end of the second spring 1303 abuts against the outer side of the positioning bolt 1304.

[0031] During the mold closing process, when the limiting rod 10 is axially inserted into the limiting sleeve 8, the ball 1302, under the elastic force of the second spring 1303, always remains in contact with the annular toothed groove 1305 on the inner wall of the limiting sleeve 8. As the limiting rod 10 continues to descend, the multiple sets of annular toothed grooves 1305 arranged axially along the ball 1302 engage and disengage in sequence. During the cycle of engagement and disengagement, the ball 1302 reciprocates and extends radially along the slide groove 1301. This reciprocating motion is transmitted to the limiting sleeve 8 through the tooth surface of the annular toothed groove 1305, causing the limiting sleeve 8 and the plate 7 to vibrate continuously in the vertical direction.

[0032] In this embodiment, the positioning mechanism 14 includes a lower groove 1401, a fan-shaped slider 1402, a push rod 1403, a third spring 1404, a push block 1405, and an inclined guide surface 1406. The lower groove 1401 is coaxially opened at the top center of the lower mold core 6. Multiple sets of fan-shaped sliders 1402 are evenly slidably arranged inside the lower groove 1401 along the circumferential direction. The inner top of the fan-shaped slider 1402 is provided with an inclined guide surface 1406, which is squeezed and adapted to the bottom end of the limiting rod 10. The push rod 1403 is fixed radially to the outer side wall of the fan-shaped slider 1402. The outer end of the push rod 1403 extends to the outer side of the lower mold core 6 and is fixedly connected to the push block 1405. The third spring 1404 is sleeved on the outer side of the push rod 1403, and the two ends of the third spring 1404 abut against the outer side wall of the fan-shaped slider 1402 and the inner side wall of the lower groove 1401, respectively.

[0033] During mold closing, after the limiting rod 10 completes its shaking and positioning action, it continues to descend and insert into the lower groove 1401. The bottom end of the limiting rod 10 contacts and presses against the inclined guide surface 1406 on the inner side of the fan-shaped slider 1402. Through the inclined surface transmission of the inclined guide surface 1406, the axial downward force of the limiting rod 10 is converted into the radial outward pushing force of the fan-shaped slider 1402. Multiple sets of fan-shaped sliders 1402 simultaneously slide radially outward along the lower groove 1401, driving the push block 1 through the push rod 1403. 405 expands radially outward synchronously until the outer side of the push block 1405 is completely in contact with the inner ring of the wheel hub insert, thus achieving full-circumference rigid limiting of the wheel hub insert; during the mold opening process, the limiting insert 10 is pulled out from the lower groove 1401, the fan-shaped slider 1402 loses the axial extrusion force, and under the action of the rebound force of the third spring 1404, it drives the push rod 1403 and the push block 1405 to retract radially inward synchronously, releasing the limiting of the wheel hub finished product, without affecting the subsequent ejection and demolding action.

[0034] In this embodiment, a tapered guide head is provided at the bottom end of the limiting rod 10, and the taper of the tapered guide head is adapted to the taper of the inclined guide surface 1406.

[0035] On the one hand, it is used to achieve smooth contact with the fan-shaped slider 1402 through the conical guide when inserting into the lower groove 1401, avoiding rigid impact between the limiting rod 10 and the inclined guide surface 1406, reducing wear on parts, and extending the service life of the mold; on the other hand, the taper of the conical guide head is perfectly matched with the taper of the inclined guide surface 1406, which can ensure that the extrusion force on multiple sets of fan-shaped sliders 1402 is completely uniform during the downward movement of the limiting rod 10, ensuring that the radial extension stroke of multiple sets of push blocks 1405 is completely consistent, further improving the positioning coaxiality of the wheel core insert, and avoiding wheel core misalignment caused by uneven extrusion force.

[0036] In this embodiment, the side wall of the lower mold core 6 is provided with guide through holes that are coaxially adapted to the push rods 1403 one by one, ensuring that the push rods 1403 can only slide linearly along the preset radial direction, and avoiding radial movement during the sliding process of the push rods 1403; the outer end of the guide through hole is provided with a hidden groove adapted to the push block 1405, which is used to fully accommodate the push block 1405 in the retracted state in the initial state of mold opening, so that the outer side of the push block 1405 is flush with the outer side wall of the lower mold core 6, eliminating the interference of the push block 1405 on the pre-installation of the wheel core insert and the ejection of the finished product.

[0037] In this embodiment, the outer shape of the push block 1405 is adapted to the inner ring shape of the wheel hub insert, which can ensure that the push block 1405 and the inner wall of the wheel hub achieve surface contact, increase the limiting contact area, reduce the pressure per unit area, and avoid deformation and damage to the inner wall of the wheel hub during the extrusion process. In addition, the outer side of the push block 1405 is provided with anti-slip texture, which can increase the friction between the push block 1405 and the inner wall of the wheel hub. During the injection molding process, it effectively restricts the circumferential rotation of the wheel hub insert and avoids the defects in the overmolding caused by the circumferential misalignment of the wheel hub.

[0038] In this embodiment, there are four push blocks 1405 on the outer side of the lower mold core 6, and the included angle between adjacent push blocks 1405 is 90°.

[0039] It can form a cross-shaped symmetrical inner support and limiting structure, which applies uniform radial limiting force in four directions to the inner ring of the wheel hub insert, avoiding wheel hub eccentricity caused by unilateral limiting and ensuring the positioning coaxiality of the wheel hub insert.

[0040] In this embodiment, the top of the lower mold core 6 is provided with an upper groove 11, and the first spring 12 is disposed inside the upper groove 11. The upper groove 11 is used to provide installation and accommodation space for the first spring 12, and at the same time to radially limit the first spring 12 to prevent bending and instability during the compression and rebound of the first spring 12. The inner top of the upper groove 11 is integrally provided with a limiting flange 1101 to limit the vertical sliding stroke of the plate 7, and the outer side of the top of the plate 7 is provided with a stepped groove 701 that cooperates with the limiting flange 1101.

[0041] The limiting flange 1101 engages with the stepped groove 701 on the plate 7 to limit the vertical sliding stroke of the plate 7. In the initial state, the limiting flange 1101 is engaged in the stepped groove 701 to limit the maximum upward position of the plate 7 and prevent the plate 7 from falling off the lower mold core 6 under the elastic force of the first spring 12. At the same time, during the ejection stage, it limits the upward ejection stroke of the plate 7 to avoid excessive ejection that could cause the wheel core to tip over or the shaft hole to be damaged, thus ensuring the smoothness of the ejection action.

[0042] The solutions in Embodiment 1 and Embodiment 2 will be further described below with reference to their specific working methods. Pre-assembly preparation stage before mold closing The mold is in a fully open state, with the upper mold 5 and lower mold 3 completely separated. The mounting plate 401 is in the lower limit reset position under the action of the return spring 403, and the ejector pin 404 falls back to the initial position synchronously with the mounting plate 401. The mounting plate 7 is in the upper limit position under the elastic support of the first spring 12, and the limiting flange 1101 engages with the stepped groove 701 for limiting. The limiting sleeve 8 is in the upper limit position synchronously with the mounting plate 7. The four sets of fan-shaped sliders 1402 are in a radially retracted state under the action of the third spring 1404, and the push block 1405 is completely housed in the hidden groove at the outer end of the guide through hole, flush with the outer wall of the lower mold core 6. At this time, the operator or robot arm coaxially mounts the hard wheel core skeleton insert on the outside of the limiting sleeve 8, and the bottom surface of the wheel core insert is supported on the top surface of the mounting plate 7, completing the pre-installation.

[0043] Mold closing guidance and coaxial pre-calibration stage The injection molding machine drives the upper mold 5 to close vertically downwards. The guide pillars 301 at the four corners of the top of the lower mold 3 are inserted into the corresponding guide grooves 501 at the bottom of the upper mold 5 first, completing the overall rough positioning and mold opening and closing guidance of the upper mold 5 and the lower mold 3, and limiting the overall horizontal misalignment of the mold. The upper mold 5 continues to descend, and the limiting rod 10 at the bottom of the upper mold core 9 is then inserted into the inner hole of the limiting sleeve 8 at the center of the plate 7. Through the clearance fit between the limiting rod 10 and the limiting sleeve 8, the coaxiality pre-calibration of the single cavity upper mold core 9 and the lower mold core 6 is completed, providing a precise coaxial reference for subsequent actions.

[0044] Insert vibration and positioning anti-jamming stage As the limiting rod 10 continues to descend and insert into the limiting sleeve 8, the shaking mechanism 13 is triggered: the second spring 1303 pushes the ball 1302 to fit tightly against the annular toothed groove 1305 on the inner wall of the limiting sleeve 8. During the descent of the limiting rod 10, the ball 1302 engages and disengages sequentially along multiple sets of continuously arranged annular toothed grooves 1305, generating radial reciprocating motion, which in turn causes the limiting sleeve 8 and the plate 7 to shake in the vertical direction. The shaking force is transmitted to the wheel core insert through the plate 7, effectively breaking the jamming between the flash, burrs, parting line protrusions on the inner wall of the wheel core shaft hole and the limiting sleeve 8, so that the wheel core insert falls smoothly to the preset pre-installation reference position and fits completely against the top surface of the plate 7, without end face tilting or hanging jamming problems.

[0045] Wheel hub full circumference inner support anti-displacement locking stage After the limiting rod 10 completes its shaking and lowering action, it continues to descend. Its bottom conical guide head inserts into the lower groove 1401 at the center of the lower mold core 6. The conical surface of the guide head presses against the inclined guide surface 1406 on the inner side of the four sets of fan-shaped sliders 1402. Through inclined surface transmission, the axial downward force is converted into radial thrust, driving the four sets of fan-shaped sliders 1402 to slide radially outward synchronously. The push rod 1403 drives the four sets of push blocks 1405 to extend radially from the hidden groove synchronously. The outer arc surface of the push block 1405 is completely flush with the inner ring of the wheel hub of the wheel core insert. During the bonding process, the plate 7 is pressed down to the top, level with the top of the lower mold core 6, completing the rigid, gapless positioning of the inner ring of the wheel hub. This eliminates the double assembly gaps between the limiting sleeve 8 and the inner shaft hole of the wheel core, and between the lower mold core 6 and the inner ring of the wheel hub. At the same time, the anti-slip texture on the outer side of the push block 1405 increases the friction, restricting the circumferential rotation of the wheel core. This achieves full constraint positioning of the wheel core insert in both the radial and circumferential directions, effectively resisting the asymmetrical lateral impact force of the TPR molten material during subsequent injection molding, and preventing the coaxiality deviation problem caused by wheel core deflection and movement during injection molding.

[0046] Mold closing and integrated injection molding stage After the pusher block 1405 locks and limits the wheel core insert, the upper mold 5 closes in place, the guide post 301 is fully inserted into the guide groove 501, the parting surfaces of the upper mold 5 and the lower mold 3 are fully fitted, and the upper mold core 9 and the lower mold core 6 close to form a closed TPR overmolding cavity; the injection molding machine injects molten TPR material into the closed cavity through the cavity feed port to complete the integrated injection molding of the outer overmolding layer of the wheel core; during the pressure holding and cooling process, the limiting rod 10 always maintains the squeezing state of the fan-shaped slider 1402, and the pusher block 1405 always maintains rigid limiting of the wheel core insert, ensuring the coaxiality of the wheel core throughout the process and avoiding defects such as uneven overmolding layer thickness and wheel surface eccentricity.

[0047] Mold opening reset and limit release stage After the injection molding and holding pressure cooling are completed, the injection molding machine drives the upper mold 5 to open vertically upward. The limiting rod 10 moves upward synchronously with the upper mold core 9 and is first pulled out from the lower groove 1401. The fan-shaped slider 1402 loses the axial extrusion force and, under the rebound action of the third spring 1404, drives the push rod 1403 and the push block 1405 to retract radially into the hidden groove, releasing the limitation on the wheel core product. The limiting rod 10 continues to move upward and is pulled out from the limiting sleeve 8. Simultaneously, the plate 7 moves upward under the elastic force of the first spring 12, initially demolding the product. The limiting rod 10 continues to move upward until the upper mold 5 reaches the fully open position. The guide post 301 completely disengages from the guide groove 501, and the mold returns to the initial open state.

[0048] Finished product ejection and demolding and cycle reset stage After the upper mold 5 is fully opened, the output end of the ejector cylinder of the injection molding machine passes through the central hole of the mold base 1 and pushes the mounting plate 401 upward in the vertical direction. The mounting plate 401 drives all the ejector pins 404 to slide upward synchronously. The top of the ejector pins 404 passes through the top of the plate 7 and pushes the molded wheel core product out of the lower mold core 6 smoothly. The operator or robot arm takes away the finished product. After the ejection action is completed, the output end of the cylinder moves downward and retracts. Under the action of the return spring 403, the mounting plate 401 drives the ejector pins 404 to move downward synchronously to reset and enter the next injection cycle.

[0049] The above description is merely a further embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope disclosed in the present invention, based on the technical solution and concept of the present invention, shall fall within the scope of protection of the present invention.

Claims

1. An anti-displacement TPR caster core integrated injection mold, comprising a mold base (1), mold feet (2) symmetrically fixed on both sides of the top of the mold base (1), a lower mold (3) fixedly installed on the top of the mold feet (2), an upper mold (5) that can be opened and closed with the lower mold (3) in the vertical direction, and an ejection mechanism (4) between the mold base (1) and the lower mold (3). Its features are: The top of the lower mold (3) is arranged in a rectangular array with several sets of lower mold cores (6). The top of the lower mold core (6) is slidably provided with a plate (7) in the vertical direction. A first spring (12) is provided between the bottom surface of the plate (7) and the top surface of the lower mold core (6). A limit sleeve (8) is coaxially fixed at the center of the plate (7). The bottom of the upper mold (5) is fixed with an upper mold core (9) that corresponds one-to-one with the lower mold core (6) and is coaxially fitted. The bottom of the upper mold core (9) is coaxially fixed with a limiting rod (10) that fits into the limiting sleeve (8). A shaking mechanism (13) is provided between the bottom outer wall of the limiting rod (10) and the inner wall of the limiting sleeve (8). The shaking mechanism (13) is used to drive the limiting sleeve (8) and the plate (7) to shake in the vertical direction during the process of the limiting rod (10) being axially inserted into the limiting sleeve (8). The lower mold core (6) is provided with a positioning mechanism (14) for radially pressing and limiting the inner ring of the wheel hub insert. The driving end of the positioning mechanism (14) cooperates with the bottom end of the limiting rod (10) so that the limiting action of the positioning mechanism (14) is linked with the insertion action of the limiting rod (10).

2. The integrated injection mold for anti-displacement TPR caster wheel core according to claim 1, characterized in that: The lower mold (3) has guide pillars (301) fixed at the top four corners, and the upper mold (5) has slots (501) at the bottom four corners that correspond to and are adapted to the guide pillars (301). The guide pillars (301) and the guide slots (501) work together to form a guide and positioning structure for opening and closing the mold.

3. The integrated injection mold for anti-displacement TPR caster wheel core according to claim 1, characterized in that: The ejection mechanism (4) includes a mounting plate (401), a fixing post (402), a return spring (403), and an ejector pin (404). The mounting plate (401) is slidably disposed between the two sets of mold feet (2) in the vertical direction. The fixing post (402) is fixed to the top of the mounting plate (401). The reset spring (403) is sleeved on the outside of the fixing post (402), and the two ends of the reset spring (403) abut against the top surface of the mounting plate (401) and the bottom surface of the lower mold (3) respectively. The ejector pin (404) and the lower mold core (6) are fixed to the top of the mounting plate (401) in a corresponding manner. The top end of the ejector pin (404) passes through the lower mold (3), the lower mold core (6) and the mounting plate (7). A hole for the cylinder output end to pass through is opened at the middle position of the mold base (1).

4. The integrated injection mold for anti-displacement TPR caster wheel core according to claim 1, characterized in that: The shaking mechanism (13) includes a slide (1301), a ball (1302), a second spring (1303), a positioning bolt (1304), and an annular toothed groove (1305). The annular toothed groove (1305) is coaxially opened on the inner wall of the limiting sleeve (8), and multiple sets of the annular toothed groove (1305) are continuously arranged along the axial direction of the limiting sleeve (8). A groove (1301) is radially opened on the bottom side wall of the limiting rod (10). A second spring (1303) is disposed inside the groove (1301). A ball (1302) is slidably disposed at the open end of the groove (1301). The open end of the groove (1301) is an arc-shaped constriction structure adapted to the ball (1302). The inner end face of the ball (1302) abuts against the outer end of the second spring (1303). The outer spherical surface of the ball (1302) meshes with the annular tooth groove (1305). A positioning bolt (1304) is threadedly connected to the bottom end of the limiting rod (10) and extends to the inner end of the groove (1301). The inner end of the second spring (1303) abuts against the outer side of the positioning bolt (1304).

5. The integrated injection mold for anti-displacement TPR caster wheel core according to claim 1, characterized in that: The positioning mechanism (14) includes a lower groove (1401), a fan-shaped slider (1402), a push rod (1403), a third spring (1404), a push block (1405), and an inclined guide surface (1406). The lower groove (1401) is coaxially opened at the top center of the lower mold core (6). Multiple sets of fan-shaped sliders (1402) are evenly slidably arranged inside the lower groove (1401) along the circumferential direction. The inner top of the fan-shaped slider (1402) is provided with a sloping guide surface (1406). The sloping guide surface (1406) is squeezed and matched with the bottom end of the limiting plug (10). The push rod (1403) is fixed radially to the outer wall of the fan-shaped slider (1402). The outer end of the push rod (1403) extends to the outer side of the lower mold core (6) and is fixedly connected to the push block (1405). The third spring (1404) is sleeved on the outer side of the push rod (1403), and the two ends of the third spring (1404) abut against the outer wall of the fan-shaped slider (1402) and the inner wall of the lower groove (1401), respectively.

6. The integrated injection mold for anti-displacement TPR caster wheel core according to claim 5, characterized in that: The bottom end of the limiting rod (10) is provided with a tapered guide head, the taper of which is matched with the taper of the inclined guide surface (1406).

7. The integrated injection mold for anti-displacement TPR caster wheel core according to claim 5, characterized in that: The side wall of the lower mold core (6) is provided with a guide through hole that is coaxially adapted to the push rod (1403) one by one, and a hidden groove adapted to the push block (1405) is provided at the outer end of the guide through hole.

8. The integrated injection mold for anti-displacement TPR caster wheel core according to claim 5, characterized in that: The outer shape of the push block (1405) is adapted to the inner ring shape of the hub of the wheel insert, and the outer side of the push block (1405) is provided with anti-slip texture to prevent the wheel insert from rotating circumferentially.

9. The integrated injection mold for anti-displacement TPR caster wheel core according to claim 5, characterized in that: There are four push blocks (1405) on the outside of the lower mold core (6), and the included angle between adjacent push blocks (1405) is 90°.

10. The integrated injection mold for anti-displacement TPR caster wheel core according to claim 1, characterized in that: The top of the lower mold core (6) is provided with an upper groove (11), and the first spring (12) is located inside the upper groove (11). The inner top of the upper groove (11) is integrally provided with a limiting flange (1101) to limit the vertical sliding stroke of the plate (7). The outer side of the top of the plate (7) is provided with a stepped groove (701) that cooperates with the limiting flange (1101).

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