Mould electric heating device for hot runner
By designing a bimetallic heating and sealing sleeve, the problems of low sealing reliability and heating efficiency in traditional mold heating devices are solved. Dynamic sealing and adaptive deformation are achieved, which improves the sealing performance and heating effect of the mold, simplifies the structure and reduces costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- DONGGUAN ZHANTUO ELECTRIC HEATING EQUIP CO LTD
- Filing Date
- 2025-05-29
- Publication Date
- 2026-05-26
AI Technical Summary
In traditional mold heating devices, screw connections are prone to loosening or corrosion, resulting in poor sealing reliability. The limited contact area of the heating wire leads to low heating efficiency. When the mold expands and contracts with temperature, the rigid connection structure cannot adapt to deformation, which may cause sealing failure or mold damage.
A bimetallic heating sealing sleeve is used, which utilizes the difference in the thermal expansion coefficient of the bimetallic strip to bend during heating, thereby achieving dynamic sealing. The screw connection is eliminated, and the heating wire is fixed by welding to ensure that the sealing sleeve adapts to the temperature and deforms tightly to the mold surface.
It significantly improves sealing reliability, simplifies product structure, reduces mold usage costs, and improves heating efficiency.
Smart Images
Figure CN224276069U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the technical field of molds, and specifically relates to a mold electric heating device for hot runners used for electric heating and sealing of molds. Background Technology
[0002] Mold heating devices are key equipment in industrial production used to maintain mold temperature and ensure molding quality. Traditional mold heating jackets are mostly sealed and fixed using bolts or mechanical clips.
[0003] For example, patent application 202311357269.0 discloses a rapidly heated injection mold, which includes a device body. A drive motor is provided on the top of the device body. A sealing ring is movably connected to the outer surface of the drive motor. A connecting rod is fixedly connected to the bottom outer surface of the drive motor. A movable cavity is opened on the outside of the connecting rod. A limiting plate is fixedly connected to the bottom outer surface of the connecting rod. A pushing screw is movably connected to the bottom outer surface of the limiting plate. When the present invention starts working, preheated plastic or rubber material is poured into the hopper. While the raw material is inside the processing chamber, a heatable solution is placed inside the heating chamber. When heating the heating chamber, the stirring ring rotates through the slide. The stirring ring stirs the solution and accelerates the heating inside the processing chamber. By rapidly transferring heat, the heating speed and effect are improved, and the raw material is melted into a molten material that can be injected into the mold. For example, patent application 202410555564.5 discloses an automated wire drawing die with a self-heating function, relating to the field of wire drawing die technology. It includes a main body, a die, and a wire coil. The die and wire coil are mounted on top of the main body, and the wire coil is mounted on both sides of the main body. Guide components are installed between the die and the wire coil. The guide components on both sides limit the movement of the metal wire, ensuring that the metal wire between the two sets of guide components coincides with the horizontal center line of the die. The die includes an inlet area, a working area, a sizing area, and an outlet area from the metal wire input direction to the output direction. A heating mechanism is provided on the side of the die closest to the metal wire input direction. This invention simultaneously heats the surface and core layers of the metal wire through the heating mechanism, reducing the temperature difference between the surface and core layers during drawing, making the drawing process smoother, and preventing the core layer temperature from becoming too low, thus avoiding cavities in the core layer during drawing.
[0004] However, these heating mechanisms have the following drawbacks:
[0005] The reliance on screw connections leads to cumbersome assembly processes, and screws are prone to loosening or corrosion under prolonged high-temperature environments, affecting sealing reliability. The limited contact area between the heating wire and heat-conducting components makes localized overheating susceptible to oxidation or poor contact, reducing heating efficiency. Furthermore, the rigid connection structure struggles to adapt to thermal expansion and contraction of the mold, potentially causing seal failure or mold damage. Therefore, improvements are urgently needed. Utility Model Content
[0006] To address the aforementioned problems, the primary objective of this invention is to provide an electric heating device for hot runner molds. This heating device utilizes the heating deformation of a bimetallic strip to achieve dynamic sealing, eliminating the need for screw connections. Simultaneously, the heating sealing sleeve adapts to temperature deformation, enabling it to tightly conform to the mold surface and significantly improve sealing reliability.
[0007] To achieve the above objectives, the technical solution of this utility model is as follows.
[0008] An electric heating device for a mold with a hot runner, the device comprising a bimetallic strip and a heating wire, wherein:
[0009] The bimetallic strip is composed of two metal layers with different coefficients of thermal expansion. The bimetallic strip is bent into an open ring to form a heating and sealing sleeve. The heating and sealing sleeve achieves sealing and fixation through the deformation generated by the bending of the bimetallic strip under heat.
[0010] The heating wire is in contact with the bimetallic strip to provide heat to the bimetallic strip;
[0011] The heating wire is disposed within the bimetallic strip and is in contact with the bimetallic strip.
[0012] The applicant's research revealed that during the mold heating process, the original bolt-fixed method deforms after heating. Although the expansion is only a few micrometers, it results in the bolts being tightly fixed and unable to be disassembled. This invention utilizes a bimetallic strip. The multiple layers of bimetallic strips with different coefficients of thermal expansion bend when heated. A block-shaped hot bimetallic strip bends into an arched shell shape when heated, while a narrow hot bimetallic strip bends into an arc shape with a certain radius. By utilizing the uneven thermal expansion and contraction of the bimetallic strip, it deforms during heating, blocking the gaps in the mold and achieving a dynamic seal. This eliminates the need for screw connections and simplifies the product structure. At the same time, the heated sealing sleeve adapts to temperature deformation, allowing it to fit tightly against the mold surface and significantly improve sealing reliability.
[0013] Furthermore, the bimetallic sheet has one layer of Ni36 and one layer of Mn72Ni10Cu18.
[0014] Furthermore, the length of the bimetallic strip is not less than three times its width, and / or the width of the bimetallic strip is not greater than 20 times its thickness.
[0015] Furthermore, the thickness of the bimetallic sheet is greater than 0.2 cm to allow for sufficient deformation.
[0016] Furthermore, the heating wire and the bimetallic sheet are connected by welding. The welding point is formed by an energy storage spot welding machine. A stable fixed relationship can be formed simply by the combination of the welding point and the heating deformation of the bimetallic sheet.
[0017] Furthermore, the opening of the bimetallic strip has a recessed step to facilitate the removal of the heating wire.
[0018] Furthermore, the contact surface between the heating wire and the bimetallic strip is a flat structure to increase the contact area, facilitate rapid heat transfer, and improve heating efficiency.
[0019] Compared with the prior art, the present invention has the following advantages:
[0020] This invention utilizes the fact that the multi-layered bimetallic strip with different coefficients of thermal expansion bends when heated, causing it to deform during the heating process and block the gaps in the mold, achieving dynamic sealing. This eliminates the need for screw connections and simplifies the product structure. At the same time, the heating sealing sleeve adapts to temperature deformation, allowing it to fit tightly against the mold surface and significantly improve sealing reliability.
[0021] Moreover, the manufacturing process has been simplified, reducing the cost of using molds. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the structure of the electric heating device implemented by this utility model.
[0023] Figure 2 This is an exploded side view of the electric heating device implemented by this utility model.
[0024] Figure 3 This is a top view of the electric heating device implemented by this utility model.
[0025] Attached diagram descriptions: 1. Heating sealing sleeve (bimetallic strip); 11. Opening; 12. Step; 2. Heating wire. Detailed Implementation
[0026] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.
[0027] Appendix Figure 1-3 As shown, this utility model provides an electric heating device for a hot runner mold. The electric heating device is installed on the hot runner and includes a bimetallic strip and a heating wire 2.
[0028] The bimetallic strip is composed of two metal layers with different coefficients of thermal expansion. The bimetallic strip is bent into an open ring to form a heating sealing sleeve 1. The heating sealing sleeve 1 achieves sealing and fixation through the deformation generated by the bending of the bimetallic strip under heat.
[0029] The heating wire 2 is in contact with the bimetallic strip to provide heat to the heating sealing sleeve 1, causing it to deform.
[0030] The heating wire 2 is disposed inside the heating sealing sleeve 1 and is in contact with the inner side of the heating sealing sleeve 1.
[0031] When heated, the multiple layers of bimetallic strips, each with a different coefficient of thermal expansion, bend. A single block of hot bimetallic strips will bend into an arched shape when heated, while a narrow hot bimetallic strip will bend into an arc shape with a certain radius. By utilizing the uneven thermal expansion and contraction of the bimetallic strips, they deform during heating, blocking the gaps in the mold and achieving dynamic sealing. This eliminates the need for screw connections and simplifies the product structure. At the same time, the heated sealing sleeve adapts to temperature deformation, allowing it to fit tightly against the mold surface and significantly improve sealing reliability.
[0032] The bimetallic sheet has one layer of Ni36 and one layer of Mn72Ni10Cu18 to meet the deformation requirements.
[0033] Typically, the length of the bimetallic strip 1 is not less than three times its width, and / or the width of the bimetallic strip is not greater than 20 times its thickness.
[0034] To ensure the deformation effect of the heating sealing sleeve 1, the thickness of the bimetallic sheet is greater than 0.2 cm to allow for sufficient deformation.
[0035] To fix the heating wire 2 to the bimetallic strip 1, the heating wire 2 and the bimetallic strip 1 are connected by welding. The welding points are formed using an energy storage spot welder, and typically four welding points are sufficient. This invention achieves a stable fixation relationship solely through the welding points combined with the heating deformation of the bimetallic strip.
[0036] To improve heat transfer efficiency, the contact surface between the heating wire 2 and the bimetallic strip 2 is flat to increase the contact area, facilitating rapid heat transfer and improving heating efficiency. The contact surface between the heating wire 2 and the heating sealing sleeve 1 is the outer surface of the heating wire 2, while the inner surface of the heating wire 2 contacts the heat flow channel. The contact surface between the heating wire 2 and the heat flow channel is also flat, further expanding the heating area and resulting in better heating performance.
[0037] The heating sealing sleeve 1 is an annular shape with an opening 11. This structure facilitates the processing of the heating sealing sleeve 1 and the installation of the heating wire 2.
[0038] Combination Figure 2 and Figure 3 Meanwhile, the bimetallic strip has a recessed step 12 at the opening 11 to facilitate the removal of the heating wire.
[0039] In summary, this invention utilizes the fact that the multi-layered bimetallic strip with different coefficients of thermal expansion bends when heated, causing it to deform during the heating process and block the gap in the mold, thus achieving dynamic sealing. This eliminates the need for screw connections and simplifies the product structure. At the same time, the heating sealing sleeve adapts to temperature deformation, allowing it to fit tightly against the mold surface and significantly improve sealing reliability.
[0040] Moreover, the manufacturing process has been simplified, reducing the cost of using molds.
[0041] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. An electric heating device for a mold with a hot runner, characterized in that: The device includes a bimetallic strip and a heating wire, wherein: The bimetallic strip is composed of two metal layers with different coefficients of thermal expansion. The bimetallic strip is bent into an open ring to form a heating and sealing sleeve. The heating and sealing sleeve achieves sealing and fixation through the deformation generated by the bending of the bimetallic strip under heat. The heating wire is in contact with the bimetallic strip to provide heat to the bimetallic strip; The heating wire is disposed within the bimetallic strip and is in contact with the bimetallic strip.
2. The electric heating device for a mold with a hot runner according to claim 1, characterized in that: The bimetallic sheet has two layers, one of which is Ni36 and the other is Mn72Ni10Cu18.
3. The electric heating device for a hot runner mold according to claim 2, characterized in that: The length of the bimetallic strip is not less than three times its width, and / or the width of the bimetallic strip is not greater than 20 times its thickness.
4. The electric heating device for a hot runner mold according to claim 2, characterized in that: The thickness of the bimetallic strip is greater than 0.2 cm.
5. The electric heating device for a hot runner mold according to claim 1, characterized in that: The heating wire is connected to the bimetallic strip by welding.
6. The electric heating device for a mold with a hot runner according to claim 1, characterized in that: The bimetallic strip has a recessed step at the opening.
7. The electric heating device for a mold with a hot runner according to claim 1, characterized in that: The contact surface between the heating wire and the bimetallic strip is a flat structure.