Nut in-mold injection molding fixing structure
By setting a flexible pin with a clearance structure inside the slider insert, the problems of inaccurate nut positioning and nut falling off in vertical injection molding machines are solved, achieving stable nut fixing and improving production efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-30
- Publication Date
- 2026-05-12
AI Technical Summary
Traditional in-mold nut fixing structures require high positioning accuracy in vertical injection molding machines, involve cumbersome manual operation, and are prone to falling off, resulting in low production efficiency and increased costs.
The design employs a flexible pin, which utilizes the elastic deformation of the flexible pin to achieve stable fixing of the nut and prevent it from falling out by setting a clearance structure inside the slider pin. This includes the clearance structure of the flexible pin, material selection, and the design of the mounting hole.
It achieves stable fixing of nuts, improves production efficiency and product quality, reduces production costs, and is suitable for fixing nuts inside the mold of vertical injection molding machines.
Smart Images
Figure CN224224365U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of injection molds, and in particular to an in-mold injection fixing structure for nuts. Background Technology
[0002] In the field of injection molding, in-mold inserts (such as nuts and bolts) are a common process for achieving functional connections in products. This process significantly improves the assembly performance of products by pre-installing metal inserts in the mold cavity and then injecting molten plastic to firmly bond them to the inserts. Among them, the mold structure with side sliders embedding nuts is widely used in the production of precision injection molded products such as automotive parts and electronic device housings because it can fix inserts in complex spatial positions.
[0003] With the increasing demand for automated production, vertical injection molding machines have become one of the mainstream equipment for in-mold insertion processes due to their advantages such as vertical mold opening and closing and convenient insert installation. Traditional in-mold nut fixing mainly relies on the rigid positioning of the slider insert, that is, the step structure of the insert head abuts against the nut end face to achieve limiting. However, this method has the following problems: high positioning accuracy is required when the nut is inserted into the mold, manual operation is cumbersome and prone to deviation; during the production process of the vertical injection molding machine, the nut is prone to falling off its installation position when the mold rotates, leading to mold compression accidents, damaging the mold and affecting production continuity; frequent machine stops for adjustment due to nut falling off increase production costs and reduce capacity. Therefore, existing in-mold nut fixing structures suffer from installation difficulties, high risk of falling off, and low production efficiency. Utility Model Content
[0004] This utility model aims to at least partially solve one of the problems in related technologies. Therefore, one of the objectives of this utility model is to provide an in-mold injection molding fixing structure for nuts, used to achieve stable fixing of nuts, solve the problems of installation difficulties and falling off the mold, and improve production efficiency and product quality.
[0005] An in-mold injection molding fixing structure for a nut includes a mold, a slider insert, and a nut. The mold has a side slider, and the slider insert is disposed within the side slider to support the nut and guide it into the product injection position. The in-mold injection molding fixing structure also includes an elastic pin. The slider insert has a machining and mounting hole, and the elastic pin is installed within the machining and mounting hole. One end of the elastic pin near the head is recessed towards the axis to form a clearance structure, giving the elastic pin elastic deformation capability to tighten the inner hole of the nut and prevent it from falling out.
[0006] Furthermore, the dimensions of the clearance structure range from 0.08 mm to 0.12 mm.
[0007] Furthermore, the elastic needle is made of spring steel, titanium alloy, or shape memory alloy.
[0008] Furthermore, the cross-sectional shape of the elastic needle is circular, square, or corrugated.
[0009] Furthermore, the cross-sectional profile of the air-avoidance structure is arc-shaped, trapezoidal, or sawtooth-shaped.
[0010] Furthermore, the length of the clearance structure of the elastic needle accounts for 1 / 5 to 1 / 3 of the total length, and the clearance area and the non-clearance area are transitioned by a chamfer.
[0011] Furthermore, the mounting hole inside the slider pin is a stepped hole, including a guide section that mates with the head of the elastic pin and a limiting section that mates with the tail. The diameter of the guide section is smaller than the diameter of the limiting section, and the guide section and the limiting section combine to form an axial limiting step.
[0012] Furthermore, the inner wall of the guide section is provided with a threaded groove, which is used to guide the rotational positioning of the elastic needle during implantation.
[0013] Furthermore, an elastic buffer element is provided at the bottom of the mounting hole, and the elastic buffer element abuts against the tail of the elastic pin.
[0014] Furthermore, the front end of the slider pin is provided with a magnetic adsorption layer, which magnetically engages with the head of the elastic pin.
[0015] Compared with the prior art, the technical solution provided in this application has the following advantages: This application uses a recessed structure at the end of the elastic pin near the head, facing the axial direction, to form a clearance structure. This allows the elastic deformation of the elastic pin to facilitate nut insertion and mechanical clamping after insertion. During installation, an installation hole is machined inside the slider insert, and the elastic pin is embedded therein, ensuring the pin head is flush with the front end of the slider insert, with the clearance structure facing the head direction. The nut is pushed in along the axis of the slider insert. At this time, the head of the elastic pin is squeezed by the inner hole of the nut. Due to the space provided by the clearance structure, it can bend inward, making room for the nut. When the nut is fully embedded in the front end of the slider insert, the head of the elastic pin passes over the shoulder of the inner hole of the nut, recovers its deformation, and tightens the inner hole wall, completing the fixation. Furthermore, after injection molding, the product is demolded along with the slider, and the elastic pin automatically resets due to the elastic characteristics of the clearance structure, facilitating nut insertion in the next cycle. This application solves the problems of nuts easily falling off and mold compression in traditional processes. It is suitable for injection molds where nuts are embedded in the side slider of the product, and has the advantages of reliable positioning, convenient installation, and improved production efficiency. Attached Figure Description
[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the present invention and, together with the description, serve to explain the principles of the present invention.
[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] In the attached image:
[0019] Figure 1 This is a schematic diagram of an embodiment of the in-mold injection fixing structure for nuts according to this application;
[0020] Figure 2 This is a cross-sectional schematic diagram and a partial enlarged view of an embodiment of the in-mold injection fixing structure for nuts according to this application;
[0021] Figure 3 This is a schematic diagram of the slider pin, elastic pin, and nut in one embodiment of the in-mold injection molding fixing structure of the nut in this application;
[0022] Figure 4 for Figure 3 A cross-sectional structural diagram of the embodiment;
[0023] Figure 5 This is a schematic diagram of the slider insert and elastic pin in one embodiment of the in-mold injection molding fixing structure of the nut in this application;
[0024] Figure 6 This is a partial view of the combination of slider insert and elastic pin in one embodiment of the in-mold injection fixing structure of the nut in this application;
[0025] Figure 7 This is a partial view of the combination of slider insert and elastic pin in another embodiment of the in-mold injection fixing structure of the nut in this application.
[0026] Figure label:
[0027] 1. A nut in-mold injection fixing structure; 10. Mold; 11. Side slider; 30. Slider insert; 31. Mounting hole; 311. Guide section; 313. Limiting section; 33. Elastic buffer element; 35. Magnetic adsorption layer; 50. Nut; 70. Elastic pin; 71. Clearance structure. Detailed Implementation
[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0029] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.
[0030] like Figure 1 - Figure 6 As shown, the present application provides an in-mold injection molding fixing structure 1 for a nut, including a mold 10, a slider insert 30, and a nut 50. The mold 10 is provided with a side slider 11, and the slider insert 30 is disposed in the side slider 11 to support the nut 50 and guide it to be inserted into the product injection position. The in-mold injection molding fixing structure 1 for the nut also includes an elastic pin 70. The slider insert 30 has a machining and mounting hole 31, and the elastic pin 70 is installed in the machining and mounting hole 31. The end of the elastic pin 70 near the head is recessed in the axial direction to form a clearance structure 71, so that the elastic pin 70 has elastic deformation capability to support the inner hole of the nut 50 and prevent it from falling out.
[0031] The side slider 11 is a movable part of the mold 10, responsible for conveying the nut 50 from the outside to the injection cavity.
[0032] The slider insert pin 30 is the core actuator of the side slider 11, directly contacting the nut 50 and guiding its insertion. The mounting hole 31 has a stepped / tapered hole machined inside to fix the elastic pin 70. The guide section 311 has a diameter with a clearance of 0.005-0.01mm between its diameter and the pin head (interference fit) to ensure positioning accuracy.
[0033] The core innovative component is the elastic pin 70, which dynamically fixes the nut 50 through elastic deformation. The head of the elastic pin 70 is provided with a clearance structure 71 (such as a groove or multi-level clearance). This application forms a clearance structure 71 by recessing the end of the elastic pin 70 near the head towards the axis, thereby utilizing the elastic deformation of the elastic pin 70 to achieve displacement during the insertion of the nut 50 and mechanical clamping after insertion. During installation, mounting holes 31 are machined inside the slider insert 30, and the elastic pin 70 is embedded in them, ensuring that the head of the pin is flush with the front end of the slider insert 30, and the clearance structure 71 faces the head direction. The nut 50 is pushed in along the axis of the slider insert 30. At this time, the head of the elastic pin 70 is squeezed by the inner hole of the nut 50. Because the clearance structure 71 has space, it can bend and deform inward to make room for the nut 50. When the nut 50 is fully embedded in the front end of the slider insert 30, the head of the elastic pin 70 passes over the shoulder of the inner hole of the nut 50, restores its deformation, and tightens the inner hole wall, completing the fixation. Furthermore, after injection molding is completed and the mold is opened, the product is demolded along with the slider. The elastic pin 70 automatically returns to its original position due to the elastic properties of the clearance structure 71, facilitating the insertion of the nut 50 in the next cycle. This application solves the problems of easy nut 50 falling off and mold compression in traditional processes. It is applicable to the injection mold 10 in which the nut 50 is embedded in the side slider 11 of the product. It has the advantages of reliable positioning, convenient installation and improved production efficiency.
[0034] Furthermore, the size of the clearance structure 71 in the first direction ranges from 0.08 mm to 0.12 mm.
[0035] Specifically, the first direction is the axial direction of the elastic pin towards the head, and the second direction is the axial direction of the elastic pin towards the tail. The clearance size directly determines the deformation and clamping force of the elastic pin 70. If the size is too small (e.g., <0.08mm), the deformation space is insufficient, and the resistance is high when the nut 50 is inserted; if it is too large (e.g., >0.12mm), the pin rigidity is insufficient, and the clamping force decreases; 0.08-0.12mm is a range verified by mechanical simulation and experiments. This size allows the radial elastic displacement generated by the pin to just fill the gap in the inner hole of the nut 50, achieving an interference fit effect. Preferably, the size of the clearance structure 71 is 0.1mm.
[0036] Furthermore, the elastic needle 70 is made of spring steel, titanium alloy, or shape memory alloy.
[0037] The elastic pin 70 requires materials with high elastic limit, fatigue resistance, and high temperature resistance. Spring steel (such as 65Mn) is low in cost and has good elasticity, making it suitable for conventional working conditions; titanium alloys (such as TC4) have high strength and light weight, making them suitable for precision molds 10 or miniaturized nuts 50; shape memory alloy materials (such as nickel-titanium alloys) have shape memory effect, which can automatically recover the preset deformation at high temperatures, enhancing the fixing reliability under complex working conditions.
[0038] Furthermore, the cross-sectional shape of the elastic needle 70 is circular, square, or corrugated.
[0039] Specifically, the circular cross-section is easy to process and has uniform radial elasticity, making it suitable for standard nuts 50; the square cross-section has good circumferential positioning (preventing the pin from rotating) and can be matched with the square groove in the inner hole of the nut 50 to enhance torsional resistance; the corrugated cross-section increases surface roughness through its undulations, improving the friction with the inner hole of the nut 50, and is especially suitable for stainless steel nuts 50 with smooth surfaces.
[0040] Furthermore, the cross-sectional profile of the clearance structure 71 is arc-shaped, trapezoidal, or sawtooth-shaped.
[0041] Specifically, the arc-shaped contour has a low stress concentration coefficient, which can extend the fatigue life of the small needle and is suitable for high-frequency use scenarios; the trapezoidal contour provides a clear deformation guide surface (the slope angle is usually 30°-45°), so that the head of the small needle deforms in a preset direction when the nut 50 is inserted; the serrated contour forms micro-tooth engagement at the clamping interface, which prevents the nut 50 from sliding axially through mechanical engagement, which is equivalent to "elastic + snap" double fixation.
[0042] Furthermore, the length of the clearance structure 71 of the elastic needle 70 accounts for 1 / 5 to 1 / 3 of the total length, and the clearance area and the non-clearance area are transitioned by a chamfer.
[0043] Specifically, the length of the clearance structure 71 of the elastic needle 70 is 1 / 5 to 1 / 3 of the total length. If it is less than 1 / 5, the clearance area is too short, the elastic deformation range is limited, and the clamping force is insufficient. If it is greater than 1 / 3, the non-clearance area is too short, the rigid support of the needle tail is insufficient, and the whole body is prone to bending.
[0044] In addition, chamfering can eliminate stress concentration at abrupt changes in cross-section, preventing the needle from breaking at the interface during frequent deformation.
[0045] Furthermore, the machining and mounting hole 31 inside the slider insert 30 is a stepped hole, including a guide section 311 that mates with the head of the elastic pin 70 and a limiting section 313 that mates with the tail. The diameter of the guide section 311 is smaller than the diameter of the limiting section 313. The guide section 311 and the limiting section 313 combine to form an axial limiting step.
[0046] Specifically, the guide section 311 has a smaller working diameter to ensure that the head of the small needle is aligned with the front end of the slider insert 30, and to accurately guide the insertion path of the nut 50; the limiting section 313 has a larger working diameter to form a stepped surface to restrict the axial movement of the small needle, preventing it from being completely pressed into the machining and mounting hole 31 when the nut 50 is inserted, and can also limit the insertion of the tail of the small needle into the machining and mounting hole 31.
[0047] Furthermore, the inner wall of the guide section 311 is provided with a threaded groove, which is used to guide the rotational positioning of the elastic needle 70 during implantation.
[0048] Specifically, the threaded groove engages with the external thread of the head of the elastic pin 70, allowing the pin to rotate into position along the threaded groove during installation, ensuring that the direction of the clearance structure 71 is aligned with the inner hole of the nut 50. When the cross-section of the elastic pin 70 is non-circular (such as square or corrugated), the threaded groove can assist in achieving circumferential positioning, preventing clamping failure due to rotational misalignment.
[0049] Furthermore, such as Figure 7 As shown, the bottom of the machining mounting hole 31 is provided with an elastic buffer element 33, which abuts against the tail of the elastic pin 70.
[0050] Specifically, the elastic buffer element 33 can not only absorb impact energy and prevent the needle from breaking due to instantaneous overload when the nut 50 is inserted at high speed, but also: for nuts 50 of different thicknesses, the compression of the buffer element can be automatically compensated to ensure that the needle head always maintains effective clamping force.
[0051] Furthermore, such as Figure 7 As shown, the front end of the slider pin 30 is provided with a magnetic adsorption layer 35, which magnetically engages with the head of the elastic pin 70.
[0052] Specifically, before the nut 50 is implanted, the magnetic adsorption layer 35 can adsorb the tip of the small needle to prevent it from sagging prematurely due to gravity or vibration, thus improving the convenience of manual feeding or robotic gripping. Furthermore, the magnetic force provides the initial fixing force, and the mechanical clamping provides the main fixing force, forming a redundant design, which is especially suitable for nut 50 implantation scenarios in the vertical direction (Z-axis) to prevent the risk of falling.
[0053] It is understood that the above embodiments only illustrate preferred embodiments of the present utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present utility model patent. It should be noted that for those skilled in the art, the above technical features can be freely combined, and several modifications and improvements can be made without departing from the concept of the present utility model, all of which fall within the protection scope of the present utility model. Therefore, all equivalent transformations and modifications made within the scope of the claims of the present utility model should fall within the coverage of the claims of the present utility model.
Claims
1. A nut in-mold injection molding fixing structure, comprising a mold and a slider insert, wherein the mold is provided with a side slider, and the slider insert is disposed within the side slider for supporting the nut and guiding it into the product injection position, characterized in that, The in-mold injection fixing structure of the nut also includes an elastic pin. The slider pin has a machining and mounting hole. The elastic pin is installed in the machining and mounting hole. The end of the elastic pin near its head is recessed in the axial direction to form a clearance structure, so that the elastic pin has elastic deformation capability and is used to tighten the inner hole of the nut to prevent it from falling off.
2. The nut in-mold injection molding fixing structure according to claim 1, characterized in that, The dimensions of the clearance structure in the first direction range from 0.08 mm to 0.12 mm.
3. The nut in-mold injection molding fixing structure according to claim 1, characterized in that, The elastic needle is made of spring steel, titanium alloy, or shape memory alloy.
4. The nut in-mold injection molding fixing structure according to claim 1, characterized in that, The cross-sectional shape of the elastic needle is circular, square, or corrugated.
5. The nut in-mold injection molding fixing structure according to claim 1, characterized in that, The cross-sectional profile of the air-sheltered structure is circular, trapezoidal, or sawtooth-shaped.
6. The nut in-mold injection molding fixing structure according to claim 1, characterized in that, The length of the clearance structure of the elastic needle is 1 / 5 to 1 / 3 of the total length, and the clearance area and the non-clearance area are transitioned by a chamfer.
7. The nut in-mold injection molding fixing structure according to claim 1, characterized in that, The machining and mounting hole inside the slider pin is a stepped hole. The machining and mounting hole includes a guide section that mates with the head of the elastic pin and a limiting section that mates with the tail. The diameter of the guide section is smaller than the diameter of the limiting section. The guide section and the limiting section combine to form an axial limiting step.
8. The nut in-mold injection molding fixing structure according to claim 7, characterized in that, The inner wall of the guide section is provided with a threaded groove, which is used to guide the rotation and positioning of the elastic needle during implantation.
9. The nut in-mold injection molding fixing structure according to claim 1, characterized in that, The bottom of the machining mounting hole is provided with an elastic buffer element, which abuts against the tail of the elastic pin.
10. The nut in-mold injection molding fixing structure according to claim 1, characterized in that, The slider needle has a magnetic adsorption layer at its front end, and the magnetic adsorption layer magnetically engages with the head of the elastic needle.