Type IV hydrogen storage container liner rotational molding mold

Abstract

The present invention provides a rotational molding die for a type IV hydrogen storage container liner, which belongs to the field of rotational molding technology. It solves the problem of low qualified rate of connection between the valve seat and the shell of the existing rotationally molded type IV hydrogen storage container liner. In this type IV hydrogen storage container liner rotational molding die, the valve seat at one end of the type IV hydrogen storage container liner is threadedly connected to a first joint assembly, the outer end of the first joint assembly is connected to the first bracket through a locking assembly with a locking tongue, and the valve seat at the other end of the type IV hydrogen storage container liner is threadedly connected to a second joint assembly, and the second joint assembly fixes the valve seat on the second hemispherical molding body. During the cooling and molding process of the product, the locking assembly is manipulated to switch the state of the first joint assembly relative to the first bracket from an axially locked state to an axially non-locked state, and the valve seat at one end is released, which significantly reduces the problem of decreased connection strength and sealing between the valve seat and the non-metallic shell due to material cooling and shrinkage.

Description

Technical Field

[0001] The invention belongs to the technical field of rotational molding, and relates to a rotational molding device, in particular to a rotational molding mold for an inner liner of a type IV hydrogen storage container. Background Art

[0002] Type IV hydrogen storage vessels are an advanced form of high-pressure hydrogen storage technology, primarily used in hydrogen fuel cell vehicles, hydrogen refueling stations, and distributed energy systems. The inner liner of a Type IV hydrogen storage vessel features metal valve seats at both ends, while the remainder is made of non-metallic materials, such as high-density polyethylene (HDPE) or polyamide (PA), offering corrosion resistance and lightweight properties. For example, a Chinese patent document discloses a roto-molded inner liner for a Type IV hydrogen storage bottle (application number 202321259711.1), as well as ISO11439:2013 and ISO15869:2009.

[0003] Rotomolding, also known as rotational molding, rotational molding, and rotational molding, is a method for hollow-molding thermoplastics. The process involves placing the plastic raw material into a mold, which is then continuously rotated along two perpendicular axes and heated. Under the influence of gravity and heat, the plastic material in the mold gradually and evenly spreads, melts, and adheres to the entire surface of the mold cavity, forming the desired shape. The final product is then cooled and shaped. Currently, many attempts have been made to apply rotomolding to the production of Type IV hydrogen storage container liners. For example, Chinese patents disclose a rotomolding device and method for high-pressure hydrogen storage bottle plastic liners (Application No. 202210695343.9), an electrically heated hydrogen cylinder rotomolding mold (Application No. 202320271741.8), a quick-opening mechanism for a hydrogen storage bottle rotomolding machine (Application No. 202321886737.9), and a rotomolding process for Type IV hydrogen storage cylinder plastic liners (Application No. 202310910938.6).

[0004] The existing rotational molding devices used to process the inner liner of type IV hydrogen storage containers and the products produced therefrom still have some shortcomings. For example, when the product is taken out of the rotational molding mold of the rotational molding device and when it is re-molded, a sling needs to be used to assist in lifting the two end covers, and multiple people need to work together, resulting in low production efficiency and high production costs. For example, the connection strength and sealing pass rate between the valve seat and the non-metallic shell in the product are low. For this reason, people have also proposed a variety of solutions, such as the rotational molding inner liner for type IV hydrogen storage bottles recorded in the Chinese patent document (202321259711.1). By adjusting the connection structure between the two, it has good sealing and ensures stable installation of the valve seat. Summary of the Invention

[0005] The present invention proposes a rotational molding die for a type IV hydrogen storage container liner. The technical problem to be solved by the present invention is how to improve the connection qualification rate between the valve seat and the shell of the type IV hydrogen storage container liner processed by the rotational molding die.

[0006] The technical problem to be solved by the present invention can be achieved through the following technical solutions: a rotational molding mold for an IV type hydrogen storage container liner, comprising a tube body molding section, a first hemispherical molding section and a second hemispherical molding section respectively located at both ends of the main body molding section, the first hemispherical molding section and the tube body molding section, as well as the second hemispherical molding section and the tube body molding section are connected by a detachable fixed connection component; it is characterized in that the first hemispherical molding section comprises a first hemispherical molding body and a first joint component that can be threadedly connected to the valve seat at one end of the IV type hydrogen storage container liner, the middle part of the first hemispherical molding body has a first avoidance hole and a positioning surface matching the valve seat, the first joint component is inserted into the first avoidance hole, and the second A first bracket is fixed on the hemispherical molding body, and the outer end of the first joint assembly is connected to the first bracket by a locking assembly having a locking tongue. The locking assembly can make the first joint assembly be in an axially locked state or an axially unlocked state relative to the first bracket. When the first joint assembly is connected to the valve seat, the valve seat contacts the positioning surface, and the locking tongue of the locking assembly contacts the first joint assembly, so that the first joint assembly is in an axially locked state relative to the first bracket, the valve seat is in a fixed state; the second hemispherical molding section includes a second hemispherical molding body and a second joint assembly that can be threadedly connected to the valve seat at the other end of the inner liner of the Type IV hydrogen storage container. The second joint assembly can fix the valve seat on the second hemispherical molding body.

[0007] During the product cooling and molding process, the locking assembly is manipulated to switch the state of the first joint assembly relative to the first bracket from an axially locked state to an axially unlocked state, thereby releasing the valve seat at one end of the product, significantly reducing the problem of decreased connection strength and sealing between the valve seat and the non-metallic shell due to material cooling shrinkage, thereby significantly improving the product qualification rate.

[0008] In the above-mentioned IV-type hydrogen storage container liner rotational molding device, the locking assembly also includes a cylinder, the cylinder body of the cylinder is fixedly mounted on the first bracket, and the locking tongue is fixedly connected to the piston rod of the cylinder; the rotational molding mold also includes a temperature sensor for monitoring the air temperature in the inner cavity of the IV-type hydrogen storage container liner, and an electromagnetic valve is connected to the air supply pipe of the cylinder, and the electromagnetic valve and the temperature sensor are both electrically connected to the control circuit. When the air temperature in the inner cavity of the IV-type hydrogen storage container liner drops to a set threshold, the control circuit controls the electromagnetic valve to switch the first joint assembly from an axially locked state to an axially unlocked state relative to the first bracket. This structure realizes automatic switching of the state of the first joint assembly relative to the first bracket according to the air temperature in the inner cavity of the IV-type hydrogen storage container liner, which not only has high consistency in monitoring results and the monitoring values ​​can intuitively reflect the cooling condition of the product, but also improves product consistency and product qualification rate.

[0009] In the above-mentioned IV-type hydrogen storage container liner rotational molding device, the movement direction of the piston rod of the cylinder is arranged perpendicular to the axis direction of the first joint component, and the first joint component has a locking mating surface that cooperates with the lock tongue, and the locking mating surface and the contact surface of the lock tongue that can contact the locking mating surface are both inclined surfaces inclined relative to the axis direction of the first joint component;

[0010] Or the movement direction of the piston rod of the cylinder is set parallel to the axial direction of the first joint assembly, and the first joint assembly has a locking mating surface that cooperates with the lock tongue, and the locking mating surface and the contact surface of the lock tongue that can contact the locking mating surface are both planes perpendicular to the axial direction of the first joint assembly.

[0011] In the above-mentioned IV type hydrogen storage container liner rotational molding device, the locking tongue is slidably mounted on the first bracket through a guide structure, and the locking assembly further includes a handle mounted on the locking tongue.

[0012] In the above-mentioned IV type hydrogen storage container liner rotational molding device, the number of the locking components is one group, or the number of the locking components is multiple groups, and the two groups of locking components are circumferentially arranged around the axis of the first joint component.

[0013] In the above-mentioned IV type hydrogen storage container liner rotational molding device, when the valve seat is pre-installed on the first hemispherical molding body, a first cooling cavity is provided between the outer side surface of the valve seat and the inner side surface of the first hemispherical molding body, and a plurality of first air vents connected to the first cooling cavity are provided on the first hemispherical molding body. During the cooling and molding process of the product, flowing air is injected into the first cooling cavity through the first air vents, so that the valve seat area in the product is cooled and molded first before the other areas. This also significantly reduces the problem of reduced connection strength and sealing between the valve seat and the non-metallic shell due to material cooling shrinkage, thereby significantly improving the product qualification rate. Based on this processing technology, the above-mentioned set threshold is preferably any value between 120℃-140℃.

[0014] In the above-mentioned IV type hydrogen storage container liner rotational molding device, a sealing plate is provided on the first joint assembly, the sealing plate is sealed and fixedly connected to the middle outer end face of the first hemispherical molding body, and the sealing plate is sealed to the first joint assembly; a sealing ring is provided between the valve seat and the first hemispherical molding body; the sealing ring and the sealing plate are respectively located at the two ends of the first cooling chamber.

[0015] In the above-mentioned IV type hydrogen storage container liner rotational molding device, when a valve seat is pre-installed on the second hemispherical molding body, a second cooling cavity is provided between the outer side surface of the valve seat and the inner side surface of the second hemispherical molding body, and a plurality of second vent holes connected to the second cooling cavity are provided on the second hemispherical molding body.

[0016] In the above-mentioned IV type hydrogen storage container liner rotational molding device, a sealing plate is provided on the second joint assembly, and the sealing plate is sealed and fixedly connected to the middle outer end face of the second hemispherical molding body, and the sealing plate is sealed to the second joint assembly; a sealing ring is provided between the valve seat and the second hemispherical molding body; the sealing ring and the sealing plate are respectively located at the two ends of the second cooling chamber.

[0017] In the above-mentioned IV-type hydrogen storage container liner rotational molding device, an air inlet hole connected to the inner cavity of the IV-type hydrogen storage container liner is opened in the first joint component, and an exhaust hole and a temperature measuring hole are opened on the second joint component, and the exhaust hole and the temperature measuring hole can be connected to the inner cavity of the IV-type hydrogen storage container liner; the temperature sensor is installed in the temperature measuring hole; heating rods are installed in the first joint component and the second joint component, and the first joint component and the second joint component can be heated by controlling the power supply of the heating rods.

[0018] Compared with the existing technology, the use of this rotational molding device to process the inner liner of a Type IV hydrogen storage container can not only accurately control the temperature of the valve seat area, but also control the cooling amplitude of the valve seat area to be greater than that of other areas, and can also release the valve seat at one end according to the cooling progress, significantly reducing the transition pull between the valve seat and the non-metallic shell, improving the connection strength and sealing between the valve seat and the non-metallic shell, and significantly improving the product qualification rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the three-dimensional structure of the rotational molding device.

[0020] Figure 2 and Figure 3 It is a three-dimensional structural diagram of the rotational molding mold in the mold closing state from different perspectives.

[0021] Figure 4 yes Figure 3 A magnified view of the local structure.

[0022] Figure 5 and Figure 6 It is a three-dimensional structural diagram of the rotational molding mold in different mold opening states.

[0023] Figure 7 It is a schematic diagram of the end face structure of the rotational molding mold.

[0024] Figure 8 yes Figure 7 Schematic diagram of the cross-sectional structure of AA.

[0025] Figure 9 yes Figure 8 A partial enlarged view of point B in the middle.

[0026] Figure 10 yes Figure 8A partial enlarged view of point C in the middle.

[0027] Figure 11 It is a schematic diagram of the three-dimensional structure of the first hemisphere forming segment.

[0028] Figure 12 It is a schematic diagram of the end face structure of the first hemispherical forming segment.

[0029] Figure 13 yes Figure 12 Schematic diagram of the cross-sectional structure of DD.

[0030] Figure 14 yes Figure 13 A partial enlarged view of point F.

[0031] Figure 15 yes Figure 12 Schematic diagram of the cross-sectional structure of EE.

[0032] Figure 16 yes Figure 15 A local enlarged view of point G.

[0033] Figure 17 It is a schematic diagram of the three-dimensional structure of the locking component in the first hemispherical forming section in an axially unlocked state.

[0034] Figure 18 It is a schematic diagram of the three-dimensional structure of the second hemisphere forming segment.

[0035] Figure 19 It is a schematic diagram of the end face structure of the second hemisphere forming segment.

[0036] Figure 20 yes Figure 19 Schematic diagram of the cross-sectional structure of HH.

[0037] Figure 21 yes Figure 20 A partial enlarged view of point J.

[0038] In the figure, 100, rotating frame; 200, rotating joint; 300, motor; 400, IV type hydrogen storage container liner; 40a, valve seat; 500, supporting rotating member; 600, transmission assembly; 700, rotational molding mold; 70a, tube body molding section; 70b, first hemispherical molding section; 70c, second hemispherical molding section; 70d, detachable fixed connection assembly; 70e, heating wire; 70f, flange portion; 70g, first annular groove; 70h, first vacuum connection hole; 70j, second annular groove; 70k, second vacuum connection hole; 1a, first hemispherical molding body; 1b, First joint assembly; 1b1, air inlet; 1b2, locking mating surface; 1c, first bracket; 1d, locking assembly; 1d1, cylinder; 1d2, locking tongue; 1e, first cooling chamber; 1f, first ventilation hole; 2a, second hemispherical molding body; 2b, second joint assembly; 2b1, exhaust hole; 2b2, temperature measuring hole; 2c, second cooling chamber; 2d, second ventilation hole; 3, handle; 4, first linear guide assembly; 5, second linear guide assembly; 5a, second guide rod; 5b, second sliding member; 6, rotating shaft; 7, rotating locking member; 8, sealing ring; 9, sealing plate; 10, heating rod. DETAILED DESCRIPTION

[0039] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0040] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0041] In the present invention, unless otherwise specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integration; they may refer to direct connection or indirect connection through an intermediate medium; they may refer to internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0042] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0043] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0044] like Figure 1 As shown, a rotational molding device for a type IV hydrogen storage container liner 400 includes a rotating frame 100, a rotational molding mold 700, a rotating joint 200, a motor 300 and a control circuit.

[0045] When the present rotational molding device is in use, the rotating frame 100 is fixedly mounted on the swing drive device. The IV type hydrogen storage container liner 400 includes a non-metallic shell and valve seats 40a located at both ends of the shell. The valve seats 40a are pre-installed in the rotational molding mold 700. The rotational molding mold 700 is used to mold the shell of the IV type hydrogen storage container liner 400. The motor 300 is mounted on the rotating frame 100. The motor 300 is used to drive the rotational molding mold 700 to rotate. The motor 300 is electrically connected to the control circuit. The rotational molding mold 700 includes an air pipe and a wire. The rotary joint 200 is mounted on the rotating frame 100. The air pipe and the wire are connected to the rotary joint 200. The rotary joint 200 prevents the rotational molding mold 700 from continuously rotating and causing the air pipe and the wire to be entangled and twisted.

[0046] like Figures 2 to 6 As shown, the rotational molding mold 700 includes a tube molding section 70a, a first hemispherical molding section 70b and a second hemispherical molding section 70c located at both ends of the main body molding section; the tube molding section 70a is mainly used to mold the circular tube section of the shell, and the first hemispherical molding section 70b and the second hemispherical molding section 70c are mainly used to pre-install the valve seat 40a and mold the hemispherical sections at both ends of the shell.

[0047] The first hemispherical molding section 70b and the tubular molding section 70a, as well as the second hemispherical molding section 70c and the tubular molding section 70a, are both connected via a removable fixed connection assembly 70d. The accompanying drawings illustrate the removable fixed connection assembly 70d as a bolt and nut assembly. Depending on the actual situation, the bolt and nut assembly can be replaced with other structures, such as an electromagnet attraction connection assembly or a quick-release buckle connection assembly.

[0048] The tubular forming section 70a is rotatably connected to the rotating frame 100 via a plurality of supporting rotating members 500 sleeved around the tubular forming section 70a. The supporting rotating members 500 are either bearings or roller-ring assemblies. As shown in the accompanying drawings, one end of the tubular forming section 70a is connected to the rotating frame 100 via a bearing, and the other end is connected to the rotating frame 100 via a roller-ring assembly. The rotational molding mold 700 not only stably rotates around the axis of the tubular forming section 70a, but also offers the advantages of low manufacturing cost and easy assembly and disassembly.

[0049] The main shaft of the motor 300 is connected to the tube forming section 70a via a transmission assembly 600. The transmission assembly 600 is shown as a gear assembly in the drawings of the specification. The gear assembly may be replaced by other structures, such as a chain sprocket assembly, depending on the actual situation.

[0050] The first hemispherical molding segment 70b includes a first hemispherical molding body 1a, and the second hemispherical molding segment 70c includes a second hemispherical molding body 2a. Both the first hemispherical molding body 1a and the second hemispherical molding body 2a are equipped with handles 3. The provision of the handles 3 makes it easier for operators to move the first hemispherical molding segment 70b and the second hemispherical molding segment 70c.

[0051] The tubular molding section 70a is connected to the first hemispherical molding body 1a of the first hemispherical molding section 70b via a first linear guide assembly 4 having a first guide rod and a first sliding member. The axis of the first guide rod is arranged parallel to the axis of the tubular molding section 70a, so that when the first hemispherical molding section 70b moves, it translates along the axis of the tubular molding section 70a. The drawings in the specification show that there are multiple first guide rods and first sliding members, and the multiple first guide rods are arranged circumferentially around the tubular molding section 70a. The first guide rods are fixedly connected to the first hemispherical molding body 1a, and the first sliding member is installed on the tubular molding section 70a. By moving the first hemispherical molding section 70b, the first hemispherical molding body 1a can be completely separated from the cooled and formed IV type hydrogen storage container liner 400.

[0052] A second linear guide assembly 5 comprising a second guide rod 5a and a second slide 5b is mounted on the tubular forming section 70a. The second hemispherical forming body 2a of the second hemispherical forming section 70c is rotatably connected to the second guide rod 5a or the second slide 5b via a rotational axis 6. The axis of the second guide rod 5a is parallel to the axis of the tubular forming section 70a, so that the second hemispherical forming section 70c translates along the axis of the tubular forming section 70a. The accompanying drawings in this specification show multiple second guide rods 5a and second slide 5b, each of which is positioned on the same side of the tubular forming section 70a. The second hemispherical forming body 2a is connected to the second guide rod 5a via the rotational axis 6, and the second slide 5b is mounted on the tubular forming section 70a. By moving the second hemispherical molding section 70c, the second hemispherical molding body 2a can be completely separated from the cooled and formed IV type hydrogen storage container liner 400, and by swinging the second hemispherical molding section 70c, the second hemispherical molding section 70c can be located on the port side of the tube body molding section 70a, which significantly reduces the impact of the second hemispherical molding section 70c on the demolding operation of the cooled and formed IV type hydrogen storage container liner 400.

[0053] The first and second sliding members 5b function identically, employing the same or different components. The first and second sliding members 5b are sleeves mounted on the guide rods or rollers positioned around the guide rods. The accompanying drawings illustrate the first sliding member as a sleeve fixedly connected to the tubular forming section 70a, while the second sliding member 5b is a roller rotatably connected to the tubular forming section 70a.

[0054] like Figure 4As shown, a rotation locking piece 7 is installed on the second linear guide component 5. When the second hemispherical molding section 70c and the tube body molding section 70a are in a facing state, the rotation locking piece 7 can put the second hemispherical molding body 2a and the second guide rod 5a or the second sliding piece 5b on the second linear guide component 5 into a rotationally locked state. In this way, the second hemispherical molding section 70c can be moved along the second linear guide component 5 and swung around the rotation axis 6 in steps, thereby improving the force application efficiency, especially during demolding, which is more conducive to the separation of the second hemispherical molding section 70c and the IV type hydrogen storage container liner 400. The attached drawings of the specification show that the rotating locking piece 7 is an elastic pin inserted and installed on the second guide rod 5a, and the second hemispherical molding body 2a is provided with a socket matching the end of the elastic pin. When the end of the elastic pin is embedded in the socket, the rotating locking piece 7 puts the second hemispherical molding body 2a and the second guide rod 5a in a rotational locking state; according to actual conditions, the elastic pin can also be replaced by other components, such as a wrench rotatably installed on the second hemispherical molding body 2a, and the second guide rod 5a has a limiting surface matching the wrench. When the wrench is rotated to contact the limiting surface of the second guide rod 5a, the rotating locking piece 7 puts the second hemispherical molding body 2a and the second guide rod 5a in a rotational locking state.

[0055] like Figures 2 to 6 As shown, multiple heating wires 70e are disposed on the outer side of the tubular molding segment 70a, the outer sides of the first hemispherical molding body 1a, and the outer sides of the second hemispherical molding body 2a. The heating wires 70e are electrically connected to the conductive wires. When energized, the heating wires 70e heat the tubular molding segment 70a, the first hemispherical molding body 1a, and the second hemispherical molding body 2a. The multiple heating wires 70e are electrically connected to a control circuit, which includes a temperature monitoring subcircuit for monitoring the cavity sidewall temperature of the rotational molding mold 700 in sections. The number of sections can range from 3 to 8. The control circuit independently controls the heating wires 70e in the corresponding sections based on the values ​​monitored by the temperature monitoring subcircuits.

[0056] like Figures 8 to 10As shown, valve seats 40a are pre-installed on the first hemispherical molding body 1a and the second hemispherical molding body 2a, and sealing rings 8 are installed between the valve seat 40a and the first hemispherical molding body 1a, and between the valve seat 40a and the second hemispherical molding body 2a. The first hemispherical molding body 1a, the second hemispherical molding body 2a, and the tube molding section 70a all have flange portions 70f. Sealing rings 8 are also installed between the flange portion 70f of the first hemispherical molding body 1a and the flange portion 70f of the tube molding section 70a, and between the flange portion 70f of the second hemispherical molding body 2a and the flange portion 70f of the tube molding section 70a. A first annular groove 70g is formed on the inner side surface of the first hemispherical molding body 1a in the area where the projection of the valve seat 40a overlaps, and on the inner side surface of the second hemispherical molding body 2a in the area where the projection of the valve seat 40a overlaps. Multiple first vacuum connection holes 70h are formed on the first hemispherical molding body 1a and the second hemispherical molding body 2a, communicating with the first annular groove 70g. Second annular grooves 70j are formed on the side surfaces of the flange portions 70f at both ends of the tube molding section 70a. Multiple second vacuum connection holes 70k are formed on the flange portions 70f of the first hemispherical molding body 1a and the second hemispherical molding body 2a, communicating with the second annular grooves 70j. The sealing ring 8 significantly improves the sealing performance of the inner cavity of the rotational molding mold 700, and vacuuming through the multiple first vacuum connection holes 70h and second vacuum connection holes 70k can significantly shorten the time required for vacuuming, thereby improving production efficiency.

[0057] like Figures 11 to 17 As shown, the first hemispherical molding section 70b also includes a first joint assembly 1b that can be threadedly connected to the valve seat 40a and a first bracket 1c fixedly connected to the outer surface of the first hemispherical molding body 1a. The first joint assembly 1b is in the form of a bolt and defines an air inlet 1b1 that communicates with the interior of the rotational molding mold 700. The air inlet 1b1 is connected to the aforementioned air pipe, allowing nitrogen to be injected into the mold cavity and flowing air to be injected into the interior of the product. The central portion of the first hemispherical molding body 1a has a first avoidance hole and a positioning surface that mates with the valve seat 40a. The first joint assembly 1b is inserted into the first avoidance hole. The outer end of the first joint assembly 1b is connected to the first bracket 1c through the locking assembly 1d. The locking assembly 1d can put the first joint assembly 1b in an axially locked state or an axially unlocked state relative to the first bracket 1c. When the first joint assembly 1b is connected to the valve seat 40a, the valve seat 40a contacts the positioning surface, and the locking assembly 1d puts the first joint assembly 1b in an axially locked state relative to the first bracket 1c, the valve seat 40a is in a fixed state.

[0058] The locking assembly 1d includes a cylinder 1d1 and a locking tongue 1d2 fixed to the piston rod of the cylinder 1d1. The cylinder body of the cylinder 1d1 is fixedly mounted on the first bracket 1c. The first joint assembly 1b has a locking mating surface 1b2 that cooperates with the locking tongue 1d2. The accompanying drawings of the specification show that the movement direction of the piston rod of the cylinder 1d1 is arranged perpendicular to the axis of the first joint assembly 1b. When the piston rod of the cylinder 1d1 is in the extended state, the locking tongue 1d2 contacts the locking mating surface 1b2 on the first joint assembly 1b, that is, the locking tongue 1d2 restricts the first joint assembly 1b from moving toward the inner cavity of the rotational molding mold 700. The contact of the valve seat 40a with the positioning surface and the connection between the first joint assembly 1b and the valve seat 40a further restrict the first joint assembly 1b from moving toward the outside of the rotational molding mold 700, thereby achieving an axial locking state of the first joint assembly 1b relative to the first bracket 1c and a fixed state of the valve seat 40a. When the piston rod of cylinder 1d1 switches from an extended state to a retracted state, locking tongue 1d2 separates from first joint assembly 1b, allowing first joint assembly 1b to move toward the interior of rotational molding mold 700. Contraction is a natural occurrence during the cooling and molding process of the product. This structure and processing significantly reduce excessive stretching between valve seat 40a and the non-metallic shell, thereby significantly improving the connection strength and sealing between valve seat 40a and the non-metallic shell, thereby increasing the product qualification rate.

[0059] The contact surfaces of the locking mating surface 1b2 and the locking tongue 1d2 that can contact the locking mating surface 1b2 are both inclined surfaces inclined relative to the axial centerline direction of the first joint assembly 1b, that is, the locking tongue 1d2 and the first joint assembly 1b are inclined surface matched. This structure can improve the fixing firmness of the valve seat 40a when the first joint assembly 1b is in an axially locked state relative to the first bracket 1c.

[0060] The accompanying drawings show two sets of locking assemblies 1d. This number can be increased or decreased based on actual circumstances. The two sets of locking assemblies 1d are symmetrically arranged, which not only improves the stress stability of the first connector assembly 1b and the consistency of its position, but also enhances the securement of the valve seat 40a.

[0061] The rotational molding mold 700 also includes a temperature sensor for monitoring the air temperature within the Type IV hydrogen storage container liner 400. A solenoid valve is connected to the air supply line of the cylinder 1d1. Both the solenoid valve and the temperature sensor are electrically connected to a control circuit. When the air temperature within the Type IV hydrogen storage container liner 400 drops below a set threshold, the control circuit controls the solenoid valve, thereby retracting the piston rod of the cylinder 1d1. The set threshold can be anywhere between 120°C and 140°C. This structure automatically switches the position of the first joint assembly 1b relative to the first bracket 1c, improving both production efficiency and product quality consistency.

[0062] According to actual conditions, the movement direction of the piston rod of the cylinder 1d1 can be adjusted from the above-mentioned perpendicular setting to the axial direction of the first joint component 1b to the setting parallel to the axial direction of the first joint component 1b. Thus, when the piston rod of the cylinder 1d1 is in an extended state, the locking tongue 1d2 contacts the locking mating surface 1b2 on the first joint component 1b, that is, the locking tongue 1d2 restricts the first joint component 1b from moving toward the inner cavity of the rotational molding mold 700; when the piston rod of the cylinder 1d1 switches from an extended state to a retracted state, the locking tongue 1d2 separates from the first joint component 1b and a larger distance is formed between the two, ensuring that the first joint component 1b can move toward the inner cavity of the rotational molding mold 700.

[0063] like Figures 13 to 16 As shown, the valve seat 40a is in a fixed state. A first cooling chamber 1e is defined between the outer surface of the valve seat 40a and the inner surface of the first hemispherical molding body 1a. The first hemispherical molding body 1a is provided with a plurality of first vent holes 1f that communicate with the first cooling chamber 1e. During the product cooling and molding process, flowing air is injected into the first cooling chamber 1e through the first vent holes 1f, causing the valve seat 40a region of the product to be cooled and molded preferentially over the remaining regions. A sealing plate 9 is sleeved on the first joint assembly 1b. The sealing plate 9 is sealed and fixedly connected to the central outer end surface of the first hemispherical molding body 1a. The sealing plate 9 is sealed to the first joint assembly 1b. The sealing ring 8 between the sealing plate 9 and the valve seat 40a and the first hemispherical molding body 1a significantly improves the sealing of the first cooling chamber 1e, reduces heat loss during the heating phase, and more accurately controls the temperature of the valve seat 40a region, improving the connection strength and sealing between the valve seat 40a and the non-metallic shell, and improving the product qualification rate.

[0064] like Figures 17 to 21 As shown, the second hemispherical molding section 70c also includes a second joint assembly 2b that can be threadedly connected to the valve seat 40a. The second joint assembly 2b is also in the form of a bolt and can secure the valve seat 40a to the second hemispherical molding body 2a. A second cooling chamber 2c is defined between the outer surface of the valve seat 40a and the inner surface of the second hemispherical molding body 2a. The second hemispherical molding body 2a is also provided with a plurality of second vents 2d that communicate with the second cooling chamber 2c. The second cooling chamber 2c and the second vents 2d function similarly to the first cooling chamber 1e and the first vents 1f. The second joint assembly 2b is also fitted with a sealing plate 9 that is sealed and fixedly connected to the central outer end surface of the second hemispherical molding body 2a. The sealing plate 9 is sealed to the second joint assembly 2b. The sealing ring 8 between the sealing plate 9 and the valve seat 40a and the second hemispherical molding body 2a significantly improves the sealing properties of the second cooling chamber 2c.

[0065] The second joint assembly 2b is provided with an exhaust hole 2b1 and a temperature measuring hole 2b2, both of which are in communication with the inner cavity of the IV type hydrogen storage container liner 400. The temperature sensor is installed in the temperature measuring hole 2b2.

[0066] A heating rod 10 is installed in both the first joint assembly 1b and the second joint assembly 2b. By controlling the power supply of the heating rod 10, the first joint assembly 1b and the second joint assembly 2b are heated, and then the valve seat 40a is heated, so that the temperature of the valve seat 40a area can be more accurately controlled, thereby improving the connection strength and sealing between the valve seat 40a and the non-metallic shell, as well as the product qualification rate.

[0067] Example 2: This example is essentially the same as Example 1 in structure and principle. The similarities are omitted here, and only the differences are described. The differences are that a manually operated locking assembly 1d can be used as a replacement. The locking assembly also includes a handle mounted on a locking tongue 1d2. The locking tongue 1d2 is slidably mounted on the first bracket 1c via a guide structure. The first joint assembly 1b has a locking mating surface 1b2 that mates with the locking tongue 1d2. The direction of movement of the locking tongue 1d2 is perpendicular to the axis of the first joint assembly 1b. A planar mating surface 1b2 and the locking tongue 1d2 are aligned perpendicular to the axis of the first joint assembly 1b.

Claims

1. A rotational molding die for an inner liner of a type IV hydrogen storage container, comprising a tube body molding section (70a), a first hemispherical molding section (70b) and a second hemispherical molding section (70c) located at both ends of the main body molding section, wherein the first hemispherical molding section (70b) and the tube body molding section (70a) are connected as well as the second hemispherical molding section (70c) and the tube body molding section (70a) via a detachable fixed connection component (70d); characterized in that: The first hemispherical molding section (70b) comprises a first hemispherical molding body (1a) and a first joint assembly (1b) capable of being threadedly connected to a valve seat (40a) at one end of an inner liner (400) of a type IV hydrogen storage container. The middle portion of the first hemispherical molding body (1a) comprises a first avoidance hole and a positioning surface matching the valve seat (40a). The first joint assembly (1b) is inserted into the first avoidance hole. A first bracket (1c) is fixed to the first hemispherical molding body (1a). The outer end of the first joint assembly (1b) is connected to the first bracket (1c). The locking assembly (1d) is connected to the first bracket (1c) through a locking assembly (1d) having a locking tongue (1d2), and the locking assembly (1d) can place the first joint assembly (1b) in an axially locked state or an axially unlocked state relative to the first bracket (1c). When the first joint assembly (1b) is connected to the valve seat (40a), the valve seat (40a) contacts the positioning surface, and the locking tongue (1d2) of the locking assembly (1d) contacts the first joint assembly (1b), so that the first joint assembly (1b) is in an axially locked state relative to the first bracket (1c), the valve seat (40a) is in a fixed state. When a valve seat (40a) is pre-installed on the first hemispherical molding body (1a), a first cooling cavity (1e) is provided between the outer side surface of the valve seat (40a) and the inner side surface of the first hemispherical molding body (1a), and a plurality of first vent holes (1f) in communication with the first cooling cavity (1e) are provided on the first hemispherical molding body (1a); during the cooling and molding process of the inner liner of the type IV hydrogen storage container, flowing air is injected into the first cooling cavity (1e) through the first vent holes (1f), so that the valve seat (40a) region in the product is cooled and molded preferentially over the remaining regions; The second hemispherical molding section (70c) comprises a second hemispherical molding body (2a) and a second joint assembly (2b) capable of being threadedly connected to a valve seat (40a) at the other end of a Type IV hydrogen storage container liner (400); the second joint assembly (2b) can fix the valve seat (40a) on the second hemispherical molding body (2a).

2. The rotational molding die for the inner liner of a type IV hydrogen storage container according to claim 1, characterized in that: The locking assembly (1d) further comprises a cylinder (1d1), the cylinder body of the cylinder (1d1) being fixedly mounted on the first bracket (1c), and the locking tongue (1d2) being fixedly connected to the piston rod of the cylinder (1d1); the rotational molding mold (700) further comprises a temperature sensor for monitoring the air temperature in the inner cavity of the IV type hydrogen storage container liner (400); an electromagnetic valve is connected to the air supply pipeline of the cylinder (1d1), and the electromagnetic valve and the temperature sensor are both electrically connected to a control circuit; when the air temperature in the inner cavity of the IV type hydrogen storage container liner (400) drops to a set threshold, the control circuit controls the electromagnetic valve to switch the first joint assembly (1b) relative to the first bracket (1c) from an axially locked state to an axially non-locked state; the set threshold is any value between 120°C and 140°C.

3. The rotational molding die for the inner liner of a type IV hydrogen storage container according to claim 2, characterized in that: The movement direction of the piston rod of the cylinder (1d1) is perpendicular to the axis direction of the first joint assembly (1b); the first joint assembly (1b) has a locking mating surface (1b2) that cooperates with the lock tongue (1d2); the locking mating surface (1b2) and the contact surface of the lock tongue (1d2) that can contact the locking mating surface (1b2) are both inclined surfaces inclined relative to the axis direction of the first joint assembly (1b); Or the movement direction of the piston rod of the cylinder (1d1) is arranged parallel to the axial centerline direction of the first joint component (1b), and the first joint component (1b) has a locking mating surface (1b2) that cooperates with the locking tongue (1d2), and the locking mating surface (1b2) and the contact surface of the locking tongue (1d2) that can contact the locking mating surface (1b2) are both planes perpendicular to the axial centerline direction of the first joint component (1b).

4. The rotational molding die for the inner liner of a type IV hydrogen storage container according to claim 1, characterized in that: The locking tongue (1d2) is slidably mounted on the first bracket (1c) via a guide structure, and the locking assembly (1d) further comprises a handle mounted on the locking tongue (1d2).

5. The rotational molding die for the inner liner of a type IV hydrogen storage container according to claim 1, 2, 3 or 4, characterized in that: The number of the locking components (1d) is one group, or the number of the locking components (1d) is multiple groups, and two groups of locking components (1d) are circumferentially arranged around the axis of the first joint component (1b).

6. The rotational molding die for the inner liner of a type IV hydrogen storage container according to claim 1, characterized in that: A sealing plate (9) is sleeved on the first joint assembly (1b), the sealing plate (9) is sealed and fixedly connected to the middle outer end surface of the first hemispherical molding body (1a), and the sealing plate (9) is sealed and connected to the first joint assembly (1b); a sealing ring (8) is provided between the valve seat (40a) and the first hemispherical molding body (1a); the sealing ring (8) and the sealing plate (9) are respectively located at two ends of the first cooling chamber (1e).

7. The rotational molding die for the inner liner of a type IV hydrogen storage container according to claim 1, 2, 3 or 4, characterized in that: When a valve seat (40a) is pre-installed on the second hemispherical molding body (2a), a second cooling cavity (2c) is provided between the outer side surface of the valve seat (40a) and the inner side surface of the second hemispherical molding body (2a), and a plurality of second vent holes (2d) in communication with the second cooling cavity (2c) are provided on the second hemispherical molding body (2a).

8. The rotational molding die for the inner liner of a type IV hydrogen storage container according to claim 7, characterized in that: A sealing plate (9) is sleeved on the second joint assembly (2b), and the sealing plate (9) is sealed and fixedly connected to the middle outer end surface of the second hemispherical molding body (2a), and the sealing plate (9) is sealed and connected to the second joint assembly (2b); a sealing ring (8) is provided between the valve seat (40a) and the second hemispherical molding body (2a); the sealing ring (8) and the sealing plate (9) are respectively located at two ends of the second cooling chamber (2c).

9. The rotational molding die for the inner liner of a type IV hydrogen storage container according to claim 2, 3 or 4, characterized in that: The first joint assembly (1b) is provided with an air inlet (1b1) that is in communication with the inner cavity of the IV type hydrogen storage container liner (400); the second joint assembly (2b) is provided with an air exhaust hole (2b1) and a temperature measuring hole (2b2); both the air exhaust hole (2b1) and the temperature measuring hole (2b2) ​​are in communication with the inner cavity of the IV type hydrogen storage container liner (400); a temperature sensor is installed in the temperature measuring hole (2b2); heating rods (10) are installed in both the first joint assembly (1b) and the second joint assembly (2b); and the first joint assembly (1b) and the second joint assembly (2b) can be heated by controlling the heating rods (10) to be energized.

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