Ball valve injection molding method

Abstract

Disclosed is a ball valve injection molding method, comprising the steps of: performing injection molding of a ball core; attaching heat insulation paper to the surface of the ball core corresponding to a glue injection port of a valve housing mold; and placing into the valve housing mold the ball core to which the heat insulation paper is attached, aligning the heat insulation paper with the glue injection port of the valve housing mold, and then starting injection molding of a valve housing. By means of the heat insulation effect of the heat insulation paper, the problem that the surface of the ball core is scalded by high-temperature glue can be effectively avoided. That is, in the present solution, the surface of the ball core is effectively protected during the injection molding of the valve housing, thereby effectively avoiding the problems of damaging the roundness of the outer surface of the ball core and affecting the roundness of the inner surface of the valve housing during the injection molding of the valve housing, thus reducing the resistance to the rotation of the ball core in the valve housing, and lowering the requirement for the output torque of a controller; in addition, because a higher degree of fitting can be maintained after the ball core rotates relative to the valve housing, the sealing performance of a valve body can be improved, thereby avoiding the problem of leakage in the valve body.

Description

A ball valve injection molding method

[0001] Cross-reference to Related Applications

[0002] The present application claims priority to the Chinese patent application No. 202411384167.2, filed on September 30, 2024, and entitled "A ball valve injection molding method", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the technical field of valve processing methods, and in particular to a ball valve injection molding method. BACKGROUND

[0004] An electric ball valve is a device for controlling the opening and closing of a ball valve through an electric actuator. Its working principle is to rotate the ball core in the valve body through the control of the electric actuator, thereby switching the on-off state of the fluid. The electric ball valve generally includes a valve body and a controller. The valve body includes a valve shell and a ball core rotatably installed in the valve shell. The controller drives the ball core in the valve body to rotate to realize the valve switching function, i.e., to switch the on-off state of the fluid.

[0005] In the injection molding process of the valve body of the electric ball valve provided by the related art, the ball core is first injection molded, and then the ball core is placed in the molding mold of the valve shell, and the valve shell is secondarily injection molded based on the ball core. After the valve shell is formed, the ball core is located in the valve shell.

[0006] However, in the related art, the inner surface roundness of the injection molded valve shell is poor, which greatly increases the rotation resistance of the ball core in the valve shell, which requires a higher output torque of the controller for controlling the rotation of the ball core. Moreover, due to the poor inner surface roundness of the valve shell, the fit between the inner surface of the valve shell and the ball core is not high, which reduces the sealing performance of the valve body and easily causes leakage problems. SUMMARY

[0007] The purpose of the present disclosure includes, for example, providing a ball valve injection molding method which can improve the inner surface roundness of the valve shell to reduce the rotation resistance of the ball core in the valve shell, and can reduce the requirement of the output torque of the controller for controlling the rotation of the ball core; and can improve the fit between the inner surface of the valve shell and the ball core to improve the sealing performance of the valve body and improve the leakage problem.

[0008] To achieve the above purpose, the present application adopts the following technical solution:

[0009] A ball valve injection molding method, comprising the steps of:

[0010] injection molding the ball core;

[0011] attaching heat insulation paper to the surface of the ball core corresponding to the glue injection port of the valve shell mold;

[0012] The ball core with the heat insulation paper is placed into the valve shell mold, and the heat insulation paper is aligned with the glue injection port of the valve shell mold, and the valve shell is injection molded.

[0013] In an optional embodiment, the area of the heat insulation paper is greater than or equal to the area of the glue injection port.

[0014] In an optional embodiment, the edge of the heat insulation paper is greater than or equal to 3mm from the edge of the glue injection port.

[0015] In an optional embodiment, the center of the heat insulation paper is aligned with the center of the glue injection port.

[0016] In an optional embodiment, the heat insulation paper is a Teflon film or a polyimide film.

[0017] In an optional embodiment, the heat insulation paper is pasted on the ball core by using a glue with a temperature resistance greater than or equal to 250℃.

[0018] In an optional embodiment, the heat insulation paper is pasted on the ball core by using a temperature resistance epoxy glue or a phenolic resin glue.

[0019] In an optional embodiment, after the valve shell is formed, the valve shell with the ball core is ejected, the ball core is rotated to a position where the heat insulation paper is aligned with the water inlet or the water outlet of the valve shell, and the heat insulation paper is torn off.

[0020] In an optional embodiment, after the valve shell is ejected, the ball core is immediately rotated and the heat insulation paper is torn off.

[0021] In an optional embodiment, the method for injection molding the ball core comprises:

[0022] Injection molding an inner sphere in one step;

[0023] Injection molding an outer sphere on the inner sphere to obtain a standard ball core in two steps.

[0024] In an optional embodiment, the outer diameter of the inner sphere is smaller than the outer diameter of the standard ball core.

[0025] In an optional embodiment, the radial thickness of the outer sphere is 1.5mm-2mm.

[0026] In an optional embodiment, the outer surface of the inner sphere is provided with a positioning part configured to cooperate with the outer sphere.

[0027] In an optional embodiment, the positioning part is circular, square, elliptical, olive-shaped or arc-shaped.

[0028] In an optional embodiment, the outer surface of the inner sphere is provided with a plurality of positioning parts, and the plurality of positioning parts are distributed in a lattice.

[0029] In an optional embodiment, the mold is preheated to 60-70℃ when the secondary injection molding outer layer of the shirt is performed.

[0030] The beneficial effects of the present application include:

[0031] In one ball valve injection molding method of the present disclosure, before the ball core is installed into the valve shell mold, a heat insulation paper is arranged on the surface of the ball core corresponding to the glue injection port in advance. When the glue is injected, the heat insulation paper can be used to isolate the position between the high-temperature and high-pressure molten glue and the ball core corresponding to the glue injection port, so as to improve the problem that the high-temperature and high-pressure molten glue directly impacts the surface of the ball core. And by using the heat insulation effect of the heat insulation paper, the problem that the surface of the ball core is scalded by the high-temperature glue can be effectively improved. In this way, the ball core can be effectively protected, and the problem that the ball core is deformed and the surface roundness is reduced due to the impact of the high-temperature and high-pressure glue can be improved. That is, the surface roundness of the ball core can be improved, and by improving the surface roundness of the ball core, the problem that the roundness of the inner surface of the valve shell is reduced when the valve shell is formed by using the ball core injection molding can be improved. Furthermore, by improving the roundness of the ball core and the inner surface of the valve shell, the resistance of the ball core when rotating in the valve shell can be reduced, and the requirement for the output torque of the controller is reduced. In addition, due to the improvement of the roundness of the ball core and the inner surface of the valve shell, the fit between the ball core and the inner surface of the valve shell is improved. In particular, the ball core can still maintain a high fit after rotating relative to the valve shell, so the sealing performance of the valve body is improved, the problem of leakage in the valve body is improved, and unnecessary resource waste is improved.

[0032] In another ball valve injection molding method of the present disclosure, the ball core is formed by two times of injection molding, that is, an inner layer ball is first formed by injection molding, and an outer layer shirt is formed by injection molding based on the inner layer ball. That is, the outer layer shirt is formed by injection molding after the inner layer ball is cooled and shaped. After the inner layer ball is shaped, even if the roundness of the inner layer ball is not good due to the uncontrollable shrinkage characteristics of the material, it can be compensated when the outer layer shirt is injected to restore good roundness. Since the thickness of the outer layer shirt is smaller relative to the thickness of the entire ball core, even if the outer layer shirt shrinks after cooling, the degree of shrinkage is smaller, so the roundness of the entire ball core is less affected, thereby achieving the purpose of obtaining a ball core with a higher outer surface roundness. And by improving the roundness of the ball core, the roundness of the valve body outside the ball core can be improved, so as to reduce the resistance of the ball core when rotating in the valve shell, and reduce the requirement for the output torque of the controller. At the same time, the fit between the ball core and the inner surface of the valve shell can also be improved. In particular, the ball core can still maintain a high fit after rotating relative to the valve shell, so the sealing performance of the valve body is improved, the problem of leakage in the valve body is improved, and unnecessary resource waste is improved. BRIEF DESCRIPTION OF DRAWINGS

[0033] The present application will be further described in detail below according to the drawings and examples.

[0034] Fig. 1 is a structural schematic diagram of a valve body in the embodiment of the present application;

[0035] Fig. 2 is an exploded structural schematic diagram of the valve body in the embodiment of the present application;

[0036] Fig. 3 is a structural schematic diagram of the valve body combined with a controller in the embodiment of the present application;

[0037] Fig. 4 is a structural schematic diagram of a ball core in the embodiment of the present application;

[0038] Fig. 5 is a sectional view of the ball core in the embodiment of the present application;

[0039] Fig. 6 is an exploded structural schematic diagram of the ball core in the embodiment of the present application;

[0040] Fig. 7 is a schematic diagram of one of the implementation manners of an inner layer ball in the embodiment of the present application;

[0041] Fig. 8 is a schematic diagram of another implementation manner of the inner layer ball in the embodiment of the present application.

[0042] In the figures: 1-ball core; 11-inner layer ball; 111-positioning part; 12-outer layer ball; 13-ball; 14-ball handle; 141-inner handle; 142-outer handle; 15-communication hole; 2-valve shell; 21-inlet and outlet water port; 3-heat insulation paper; 4-controller; 5-valve body. DETAILED DESCRIPTION

[0043] In order to make the technical problems solved by the present application, the technical solutions adopted and the technical effects achieved more clear, the technical solutions of the embodiments of the present application are described in further detail below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0044] In the description of the present application, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood in a broad sense, for example, can be fixedly connected, or can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present disclosure can be understood according to the specific circumstances.

[0045] In the present application, unless specifically and expressly defined otherwise, a first feature is "on" or "under" a second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "over" the second feature includes that the first feature is directly above and obliquely above the second feature, or only means that the first feature is higher in horizontal height than the second feature. The first feature "under", "below" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or only means that the first feature is lower in horizontal height than the second feature.

[0046] The electric ball valve is a device for controlling the opening and closing of the ball valve through the electric actuator. The working principle is to realize the rotation of the ball core of the valve body through the control of the electric actuator, so as to switch the on-off state of the fluid. The electric ball valve usually comprises a valve body and a controller, the valve body comprises a valve shell and a ball core rotatably installed in the valve shell, and the controller drives the ball core in the valve body to rotate to realize the valve switching function, that is, to realize the switching of the fluid on-off state.

[0047] The injection molding process of the valve body of the electric ball valve provided by the related art is to first injection mold the ball core, and then place the ball core in the molding mold of the valve shell, and directly injection mold the valve shell on the basis of the ball core. After the valve shell is formed, the ball core is just located in the valve shell.

[0048] The inventors found that in the process of using the ball core for secondary injection to form the valve shell, the part of the ball core opposite to the glue inlet of the injection mold will appear scalding phenomenon under the impact of high temperature and high pressure molten glue, which will cause the surface of the ball core to deform and cause the surface of the ball core to be not round. The quality of the inner surface of the valve shell is actually determined by the quality of the outer surface of the ball core, that is, the surface roundness of the ball core determines the roundness of the inner surface of the valve shell. The surface deformation of the ball core and the poor roundness will cause the roundness of the inner surface of the valve shell to be poor. Under the influence of the poor roundness of the outer surface of the ball core and the inner surface of the valve shell, the rotation resistance of the ball core in the valve shell after molding is extremely large, which puts higher requirements on the output torque of the controller. Moreover, the ball core and the valve shell are not high enough in adhesion, which reduces the sealing performance of the valve body and easily causes leakage. Especially in the high-pressure fluid application scenario, the valve body is prone to leakage.

[0049] Please refer to FIG. 1, FIG. 2 and FIG. 3, the valve body 5 of the ball valve includes a valve shell 2 and a ball core 1, the ball core 1 is rotatably arranged in the valve shell 2, the ball core 1 includes a ball body 13 and a ball handle 14 connected to one side of the ball body 13, the ball handle 14 extends out of the valve shell 2 and is configured to be connected with the controller 4. The valve shell 2 is provided with water inlet and outlet ports 21, the ball body 13 is provided with a communication hole 15, the communication hole 15 is configured to be able to communicate with the water inlet and outlet ports 21; wherein, when the ball core 1 is rotated to deviate from the communication hole 15 to the water inlet and outlet ports 21, the ball valve is closed, that is, the communication hole 15 is not communicated with the water inlet and outlet ports 21; when the ball core 1 is rotated to the communication hole 15 and the water inlet and outlet ports 21 are opposite and communicated, the ball valve is conducted.

[0050] In order to overcome the above technical problems, the embodiment provides a ball valve injection molding method, comprising:

[0051] S1. injection molding the ball core 1;

[0052] S2. setting the heat insulation paper 3 on the surface of the ball core 1 corresponding to the glue injection port of the valve shell mold, that is, setting the heat insulation paper 3 at the position corresponding to the glue injection port of the valve shell mold on the ball core 1;

[0053] S3. placing the ball core 1 provided with the heat insulation paper 3 into the valve shell mold, and making the heat insulation paper 3 oppositely distributed with the glue injection port of the valve shell mold, and then starting injection molding to form the valve shell 2.

[0054] In the valve shell mold, there is a valve shell cavity, a mold core corresponding to the communication hole 15 of the ball core 1 is arranged in the valve shell cavity, the ball core 1 is clamped and fixed on the mold core through the communication hole 15, and the heat insulation paper 3 attached to the ball core 1 after clamping is opposite to the glue injection port of the valve shell mold.

[0055] In the injection molding process, if the position of the ball core 1 covered by the heat insulation paper 3 is not covered by the heat insulation paper 3, it will be directly impacted by the high-temperature and high-pressure glue liquid, causing deformation; after the heat insulation paper 3 is set, although this part will still be impacted by high temperature and high pressure, the impact is blocked by the heat insulation paper 3, and under the heat insulation effect of the heat insulation paper 3, the part will not quickly soften, so it is not easy to deform under the impact of the high-temperature and high-pressure glue liquid. Although the remaining area not attached with the heat insulation paper 3 will directly contact the high-temperature glue liquid to cause the temperature to quickly rise, the glue liquid will quickly depressurize after entering the valve shell cavity, so the problem of high-pressure impact deformation of the high-temperature part of the ball core 1 will not occur.

[0056] Therefore, by the ball valve injection molding method of the present embodiment, the heat insulation paper 3 is arranged on the surface of the ball core 1 at the position opposite to the glue injection port before the ball core 1 is placed into the valve shell mold; when the glue is injected, the problem that the high-temperature and high-pressure molten glue directly impacts the surface of the ball core 1 can be improved, and by the heat insulation effect of the heat insulation paper 3, the problem that the surface of the ball core 1 is scalded by the high-temperature glue can be effectively improved. In this way, the present application can effectively protect the surface of the ball core 1 when the valve shell 2 is injection molded, improve the problem that the outer surface of the ball core 1 is deformed and the roundness is destroyed, and further improve the problem that the roundness of the inner surface of the valve shell 2 is destroyed, so as to reduce the resistance that the ball core 1 receives when rotating in the valve shell 2 by improving the roundness of the ball core 1 and the roundness of the inner surface of the valve shell 2, and reduce the requirement for the output torque of the controller 4; in addition, due to the improvement of the roundness of the ball core 1 and the inner surface of the valve shell 2, the fit between the ball core 1 and the inner surface of the valve shell 2 is improved; in particular, the ball core 1 can still maintain a high fit after rotating relative to the valve shell 2, so the sealing performance of the valve body 5 is improved, and the problem of leakage in the valve body 5 is improved.

[0057] It should be noted that when the ball core 1 provided with the heat insulation paper 3 is placed in the valve shell mold, the glue injection port is opposite to the peripheral wall of the ball core 1 which is not provided with the communication hole 15, that is, the heat insulation paper 3 covers the peripheral wall of the ball core 1 which is not provided with the communication hole 15 to be distributed opposite to the glue injection port.

[0058] Optionally, the area of the heat insulation paper 3 is greater than or equal to the area of the glue injection port, and the center of the heat insulation paper 3 is aligned with the center of the glue injection port.

[0059] Based on this arrangement, it is ensured that the heat insulation paper 3 can reliably withstand the impact of the glue flowing from the glue injection port into the mold, and the problem that the high-temperature and high-pressure glue accidentally breaks through the heat insulation paper 3 is improved, so as to ensure that the heat insulation paper 3 can provide effective protection.

[0060] Optionally, the distance from the edge of the heat insulation paper 3 to the edge of the glue injection port is greater than or equal to 3 mm, for example, 3 mm, 3.2 mm, 4 mm, etc., which is not limited here.

[0061] In this way, by ensuring that the heat insulation paper 3 can cover the glue extruded by the glue injection port on the surface of the ball core 1, the coverage area of the heat insulation paper 3 on the ball core 1 is further expanded, so as to provide a larger protection area for the ball core 1 and further ensure the stability of the surface quality of the ball core 1, that is, by covering the ball core 1 with the heat insulation paper 3 of a larger size, it is beneficial to ensure that the position of the ball core 1 opposite to the glue injection port is effectively covered and protected by the heat insulation paper 3. In addition, since there may be some errors in arranging the heat insulation paper 3 on the surface of the ball core 1, arranging the heat insulation paper 3 of a larger size can compensate for the errors and ensure that the heat insulation paper 3 can provide effective protection.

[0062] It should be understood that in other embodiments, the heat insulation paper 3 can be wrapped on the outside of the entire ball core 1, that is, the heat insulation paper 3 covers not only the position corresponding to the glue injection port of the ball core 1, but also covers the heat insulation paper 3 at other positions except the position corresponding to the glue injection port.

[0063] Optionally, the heat insulation paper 3 is a Teflon film or a polyimide film.

[0064] The Teflon film has extremely high high-temperature resistance and can maintain its physical and chemical properties stable in extremely high-temperature environment, which makes it very suitable as a heat insulation material to prevent high-temperature molten glue from scalding in the injection molding process. In addition, the Teflon film has strong corrosion resistance to most chemical substances, which means that even if the molten glue contains some corrosive components, the Teflon film will not be damaged in the injection molding process.

[0065] The polyimide film also has excellent high-temperature resistance and can maintain its structural stability in high-temperature environment, which makes it also effective in preventing high-temperature molten glue from scalding the ball core 1 in the injection molding process. In addition, the polyimide film has high mechanical strength and can withstand certain pressure and impact force, and it can maintain its integrity in the injection molding process to ensure the heat insulation effect. The polyimide film has good resistance to a variety of chemical substances and radiation, which further increases its applicability in the injection molding process.

[0066] Optionally, the heat insulation paper 3 is attached to the position corresponding to the glue injection port of the ball core 1.

[0067] Optionally, the heat insulation paper 3 is provided with an adhesive, and the heat insulation paper 3 is adhered to the ball core 1 by the adhesive; or, the heat insulation paper 3 is additionally adhered to the ball core 1 by double-sided tape or glue.

[0068] Optionally, the heat insulation paper 3 is adhered to the ball core 1 by a glue with a temperature resistance greater than or equal to 250°C.

[0069] In the injection molding process, the temperature of the molten glue is high, sometimes even exceeding 200°C; therefore, choosing a glue with a temperature resistance greater than or equal to 250°C to adhere the heat insulation paper 3 is conducive to ensuring that the glue does not fail or melt in a high-temperature environment, thereby maintaining the firm adhesion between the heat insulation paper 3 and the ball core 1.

[0070] Optionally, the heat insulation paper 3 is adhered to the ball core 1 by temperature-resistant epoxy glue or phenolic resin glue.

[0071] The epoxy glue can maintain its bonding strength and stability in high temperature environment, and is not easy to soften or melt, which enables it to withstand the impact of high temperature molten glue without failure in the injection molding process; at the same time, the epoxy glue has excellent adhesion, which can firmly paste the heat insulation paper 3 on the ball core 1, and the adhesion can remain stable at high temperature, ensuring that the heat insulation paper 3 is not easy to fall off.

[0072] The phenolic resin glue has extremely high high-temperature resistance, can maintain the stability of its physical and chemical properties at high temperature, and has high hardness and strength after curing, which can withstand certain pressure and impact force, which helps to ensure that the heat insulation paper 3 will not fall off due to external force during the injection molding process.

[0073] It should be understood that in other embodiments, the heat insulation paper 3 can be wrapped on the entire outside of the ball core 1, that is, the heat insulation paper 3 covers not only the position of the ball core 1 corresponding to the glue injection port, but also covers the heat insulation paper 3 at other positions except the position corresponding to the glue injection port. In this full wrapping embodiment, the heat insulation paper 3 can not need to be pasted on the outside of the ball core 1, but can be stably attached to the outside of the ball core 1 by its own elasticity or plasticity.

[0074] Optionally, the injection molding method of the present embodiment, after the valve shell 2 is formed, the valve shell 2 with the ball core 1 is ejected, the ball core 1 is rotated to a position where the heat insulation paper 3 is opposite to the water inlet or outlet of the valve shell 2, so as to tear off the heat insulation paper 3 from the water inlet or outlet.

[0075] After the shaped valve shell 2 is ejected, the ball core 1 is rotated to a position where the heat insulation paper 3 is opposite to the water inlet or outlet of the valve shell 2, so that the tool can extend into the valve shell 2 from the water inlet or outlet to tear off the exposed heat insulation paper 3. The heat insulation paper 3 is rotated to be opposite to the water inlet or outlet of the valve shell 2, and then torn off, which ensures the operability of tearing off the heat insulation paper 3.

[0076] Tearing off the heat insulation paper 3 can avoid its remaining on the ball core 1 and falling off from the ball core 1 to cause the problem of blocking the water inlet or outlet 21 of the valve shell 2 or the pipeline provided with the valve body 5 during later use.

[0077] It should be noted that the valve shell 2 is provided with two water inlets and outlets 21 which are communicated with each other, one of the water inlets and outlets 21 serves as the above-mentioned water inlet, and the other water inlet and outlet 21 serves as the above-mentioned water outlet.

[0078] Optionally, after the valve shell 2 is ejected, the ball core 1 is immediately rotated and the heat insulation paper 3 is torn off.

[0079] For example, after the valve shell 2 is ejected, the ball core 1 is rotated and the heat insulation paper 3 is torn off within about 1-5 minutes.

[0080] After the valve shell 2 is ejected, the temperature of the valve shell 2 is still in a high range, at this time, the ball core 1 is also relatively easy to rotate, and the difficulty of tearing off the heat insulation paper 3 is relatively low, so the tearing off operation of the heat insulation paper 3 is performed immediately after the valve shell 2 is ejected, which can reduce the tearing difficulty. When operating, in order to avoid scalding the hands, the valve shell 2 can be clamped and fixed by using a clamp to facilitate operation.

[0081] The inventor has also found that the ball core provided by the related art is a one-time injection molding structure. Due to the uncontrollable shrinkage of the plastic material cooling degree, after injection molding and cooling, the ball core material at different positions is prone to different degrees of cooling shrinkage, which causes the problem that the roundness of the ball core surface is difficult to guarantee. The roundness of the inner surface of the valve shell based on the ball core is also affected.

[0082] In order to overcome the above technical problems, referring to FIGS. 4, 5 and 6, the method for injection molding the ball core 1 includes:

[0083] S11. One-time injection molding of an inner layer ball 11, the outer diameter size of the inner layer ball 11 is smaller than the outer diameter size of the ball core 1 to be obtained (that is, the outer diameter size of the inner layer ball 11 is smaller than the outer diameter size of the standard ball core 1);

[0084] S12. Secondary injection molding of an outer layer ball 12 based on the inner layer ball 11 to obtain the ball core 1 (that is, the standard ball core 1).

[0085] The injection molding method of the embodiment at least needs to provide two sets of molds, for example, a first mold and a second mold. The first mold has a first cavity, the size of the first cavity is smaller than the outer diameter size of the ball core 1 to be obtained (that is, the outer diameter size of the standard ball core 1), and the inner layer ball 11 can be obtained after injection molding and cooling in the first cavity. The outer diameter size of the inner layer ball 11 is smaller than the outer diameter size of the standard ball core 1. The second mold has a second cavity, the size of the second cavity is equal to the outer diameter size of the standard ball core 1. The inner layer ball 11 is placed in the second cavity, and the standard ball core 1 can be obtained after injection molding and cooling in the second cavity.

[0086] Optionally, the inner layer ball 11 has a center hole corresponding to the communication hole 15 of the ball core 1, and the size of the center hole is the same as that of the communication hole 15 of the standard ball core 1.

[0087] The center hole of the inner layer ball 11 after molding is exactly matched with the size of the communication hole 15 of the standard ball core 1, so the outer layer ball 12 after molding does not need to cover the center hole of the inner layer ball 1. Based on this, in the second mold for making the outer layer ball 12, a mold core matching the size of the center hole can be directly provided, and when the inner layer ball 11 is installed, the center hole can be firmly and reliably clamped on the mold core of the second mold.

[0088] It can be understood that the central hole of the inner sphere 11 constitutes the communication hole 15 of the ball core 1.

[0089] In order to improve the uniformity of the outer sphere 12, ensure that the outer sphere 12 can completely cover the outer surface of the inner sphere 11, in the first mold, a mold core corresponding to the size of the communication hole 15 of the ball core 1 is arranged, so that the inner sphere 11 molded by the first mold has the communication hole 15; in the second mold, a mold core corresponding to the size of the communication hole 15 is also arranged, when the inner sphere 11 is placed in the second mold, the communication hole 15 in the center of the inner sphere 11 can be directly aligned with the mold core of the second mold for clamping and fixing, so that the inner sphere 11 can be stably and reliably fixed in the second mold, avoiding the problem of offset of the gel impacting the inner sphere 11 during injection molding; in particular, the mold core of the second mold supports the inner sphere 11 from the middle, so that the inner sphere 11 is fixed in the center of the second cavity, ensuring that the inner sphere 11 maintains uniform spacing with the cavity wall of the second cavity, so that the gel entering the second cavity during injection molding can uniformly cover the outer periphery of the inner sphere 11, to obtain the outer sphere 12 with uniform thickness.

[0090] The injection molding method of the ball core 1 of the embodiment adopts a two-time injection molding process, first one-time injection molding of the inner sphere 11 with a smaller outer diameter size than the standard size of the ball core 1, and then placing the inner sphere 11 in the mold for injection molding of the outer sphere 12, the outer sphere 12 being wrapped around the inner sphere 11, and the combination of the two being just able to obtain a structure that conforms to the designed standard size of the ball core 1. The ball core 1 obtained by the two-time injection molding process, after the inner sphere 11 is cooled and shaped, the outer sphere 12 is injection molded, and after the inner sphere 11 is shaped, even if it is affected by the uncontrollable shrinkage characteristics of the material, resulting in poor roundness of the inner sphere 11, it can be compensated for when the outer sphere 12 is injection molded to restore good roundness. Since the thickness of the outer sphere 12 is smaller relative to the thickness of the entire ball core 1, even if the outer sphere 12 shrinks after cooling, the degree of shrinkage is smaller, so the roundness of the entire ball core 1 is less affected, thereby achieving the purpose of obtaining a ball core 1 with a higher roundness of the outer surface.

[0091] In the case of a ball core 1 with higher roundness obtained by the injection molding method based on the scheme, when the valve shell 2 is injection molded based on the ball core 1, the roundness of the inner circular surface of the valve shell 2 can also be better guaranteed, thereby reducing the resistance of the ball core 1 rotating in the valve shell 2, and reducing the requirement for the output torque of the controller 4; in addition, since the ball core 1 can maintain a higher fit after rotating relative to the valve shell 2, the sealing performance of the valve body 5 can be improved, and the problem of leakage in the valve body 5 can be avoided.

[0092] It should be understood that the sphere 13 includes the inner sphere 11 and the outer sphere 12 wrapped around the inner sphere 11.

[0093] Optionally, the ball stem 14 is connected with at least one of the inner sphere 11 and the outer sphere 12, and the connection manner includes but is not limited to one-piece forming, bonding, or threaded connection.

[0094] For example, in some embodiments, the ball stem 14 is connected with only the inner sphere 11; in some other embodiments, the ball stem 14 is connected with only the outer sphere 12; in yet some other embodiments, the ball stem 14 is connected with both the inner sphere 11 and the outer sphere 12.

[0095] Optionally, the ball stem 14 includes an inner stem 141 and an outer stem 142, the inner stem 141 is connected with the inner sphere 11, the outer stem 142 is connected with the outer sphere 12, and the outer stem 142 is sleeved or wrapped outside the inner stem 141.

[0096] Optionally, the connection manner of the inner stem 141 with the inner sphere 11 includes but is not limited to one-piece forming or bonding.

[0097] Optionally, the connection manner of the outer stem 142 with the outer sphere 12 includes but is not limited to one-piece forming or bonding.

[0098] Optionally, the radial thickness of the outer sphere 12 is 1.5mm-2mm, for example, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, etc., which is not limited herein.

[0099] The inventor has found that controlling the radial thickness of the outer sphere 12 to be 1.5mm-2mm can better cope with the shrinkage of the plastic material when it is cooled, which brings adverse effects on the shape of the ball core 1. The plastic material will undergo shrinkage after injection molding, and the thickness of the outer sphere 12 directly affects the degree of shrinkage. A thinner outer sphere 12 (such as 1.5mm-2mm) has a smaller impact on the overall roundness of the ball core 1, because even if the outer sphere 12 shrinks to a certain extent, due to its limited thickness, it will not significantly affect the overall shape of the ball core 1. In addition, the thickness of the outer sphere 12 is more than 1.5mm, which can ensure that it has sufficient durability and avoid being too thin to wear out. Moreover, the thickness of the outer sphere 12 determines the width of the gap between the inner sphere 11 and the second mold cavity wall during secondary injection molding. When the gap is too small, the flow area of the molten glue in the gap is too small, and the flow speed is too slow, which can cause the molten glue to fail to fully fill the second mold cavity, resulting in defects in the formed outer sphere 12. Controlling the thickness of the outer sphere 12 to be more than 1.5mm can effectively improve the above-mentioned problems.

[0100] Optionally, the radial thickness of the outer sphere 12 is 1.6-1.7mm.

[0101] Optionally, the outer surface of the inner sphere 11 is provided with positioning portions 111, which are positioning protrusions and / or positioning recesses; that is, in some embodiments, the positioning portions 111 only include positioning protrusions; in other embodiments, the positioning portions 111 only include positioning recesses; and in yet other embodiments, the positioning portions 111 include both positioning protrusions and positioning recesses.

[0102] The positioning portions 111 provided on the outer surface of the inner sphere 11 can form a concave-convex structure that interlock with each other at the joint surface of the inner sphere 11 and the outer sphere 12 after the outer sphere 12 is injection molded, so as to effectively improve the reliability of the joint of the inner sphere 11 and the outer sphere 12 and avoid the problem of mutual separation of the inner sphere 11 and the outer sphere 12.

[0103] For example, when the surface of the inner sphere 11 is provided with positioning protrusions, the outer sphere 12 will form corresponding recesses at positions corresponding to the positioning protrusions after the outer sphere 12 is injection molded; and when the surface of the inner sphere 11 is provided with positioning recesses, the outer sphere 12 will form corresponding protrusions at positions corresponding to the positioning recesses after the outer sphere 12 is injection molded.

[0104] Optionally, the inner sphere 11 is provided with a plurality of positioning portions 111, which can be individually provided as positioning protrusions, individually provided as positioning recesses, or provided in combination of positioning protrusions and positioning recesses. Through the provision of the plurality of positioning portions 111, the joint reliability between the inner sphere 11 and the outer sphere 12 can be further ensured.

[0105] Optionally, referring to FIG. 7, the plurality of positioning portions 111 are distributed in a dot matrix on the outer surface of the inner sphere 11.

[0106] Each positioning portion 111 can form a joint point with the outer sphere 12, and the dot matrix distribution causes the joint points to be uniformly distributed on the surface of the inner sphere 11, thereby forming a strong joint network. This network structure can significantly improve the joint strength between the inner sphere 11 and the outer sphere 12 and realize the resistance to the interaction force between the inner sphere 11 and the outer sphere 12 on each square.

[0107] Optionally, the positioning portions 111 distributed in the dot matrix on the outer surface of the inner sphere 11 can be circular, square, elliptical, olive-shaped, or other shapes.

[0108] Optionally, referring to FIG. 8, the positioning portions 111 are arc-shaped strips, and are arranged perpendicular to the rotation direction of the ball core 1.

[0109] In other words, the ball core 1 rotates around the rotation axis a, i.e., the inner sphere 11 rotates around the rotation axis a; the inner sphere 11 has a first end and a second end distributed along the direction of the rotation axis a; the ball handle 14 is distributed at the first end of the inner sphere 11, i.e., the inner handle 141 is distributed at the first end of the inner sphere 11; the two ends of the length extension direction of the positioning part 111 extend to the first end and the second end of the inner sphere 11, respectively.

[0110] Wherein, the rotation direction of the ball core 1 refers to the direction in which the ball core 1 rotates around the rotation axis a during the rotation of the ball core 1 driven by the controller 4 through the ball handle 14; during the rotation of the ball core 1, a strong friction force will be generated between the ball core 1 and the valve shell 2, which will hinder the rotation of the ball core 1 in this direction; similarly, during the rotation, the inner sphere 11 and the outer sphere 12 will also generate a mutual force around the rotation direction of the ball core 1, and the positioning part 111 is arranged in an arc-shaped strip shape and perpendicular to the rotation direction of the ball core 1, which can exactly provide the maximum area to resist the mutual force, achieving the best effect of strengthening the combination of the inner sphere 11 and the outer sphere 12, so as to ensure that the inner sphere 11 and the outer sphere 12 reliably rotate synchronously and are not easily separated from each other.

[0111] Optionally, the outer sphere 12 can completely cover the positioning part 111.

[0112] The outer sphere 12 completely covers the positioning part 111, which is beneficial to completely use the outer surface of the outer sphere 12 as the outer surface of the entire ball core 1. In this way, the smoothness and integrity of the outer surface of the entire ball core 1 can be ensured, and the sealing performance of the combination of the ball core 1 and the valve shell 2 can be ensured.

[0113] Optionally, when the outer sphere 12 is formed by secondary injection molding, the mold is preheated to 60-70°C, for example, 60°C, 62°C, 65°C, 67°C, 70°C, etc., which is not limited specifically herein.

[0114] The preheating of the mold to 60-70°C is based on the comprehensive consideration of the characteristics of the injection molding material and the process requirements. On the one hand, this temperature range can ensure that the material has good fluidity and permeability during injection molding, reduce the temperature difference between the material and the mold during injection, thereby reducing the viscosity of the material and promoting better flow and filling of the mold cavity, which is crucial for ensuring that the outer sphere 12 can completely cover the positioning part 111 and form a uniform and dense structure. On the other hand, it can avoid the degradation of the material or the damage of the mold caused by too high temperature; at the same time, this temperature range is also helpful to achieve the required solidification degree in a shorter time, thereby ensuring the quality and performance of the product.

[0115] In the description of the present document, it should be understood that the terms "upper", "lower", "left", "right", and the like orientation or position relationship are only for the convenience of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only used to distinguish in the description, and have no special meaning.

[0116] In the description of the present specification, the description referring to the terms "an embodiment", "an example" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example.

[0117] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that those skilled in the art can understand.

[0118] The technical principles of the present application are described above in conjunction with specific embodiments. These descriptions are only for the purpose of explaining the principles of the present application, and cannot be interpreted in any way as a limitation on the scope of protection of the present application. Based on the explanation here, those skilled in the art do not need to make creative efforts to think of other specific embodiments of the present application, and these embodiments will fall within the scope of protection of the present application. Industrial applicability

[0119] The ball valve injection molding method of the present disclosure can improve the roundness of the inner surface of the valve shell to reduce the rotational resistance of the ball core in the valve shell, and can reduce the output torque requirement of the controller controlling the rotation of the ball core; Moreover, it can improve the fit between the inner surface of the valve shell and the ball core to improve the sealing of the valve body, improve the leakage problem, and improve the unnecessary resource waste phenomenon.

Claims

1. A method of injection molding a ball valve, the method comprising: The application relates to a method for manufacturing a valve shell by injection molding. The method comprises the following steps: attaching heat insulation paper to the surface of a ball core corresponding to the glue injection port of a valve shell mold; arranging the ball core with the heat insulation paper in the valve shell mold, and aligning the heat insulation paper with the glue injection port of the valve shell mold, and then injection molding the valve shell.

2. The ball valve injection molding method according to claim 1, characterized in that, The area of the heat insulation paper is greater than or equal to the area of the glue injection port.

3. The ball valve injection molding method according to claim 2, characterized in that, The edge of the heat insulation paper is greater than or equal to 3mm away from the edge of the glue injection port.

4. Injection molding method of a ball valve according to any one of claims 1-3, characterized in that, The center of the heat insulation paper is aligned with the center of the glue injection port.

5. Injection molding method of a ball valve according to any one of claims 1-4, characterized in that, The heat insulation paper is a Teflon film or a polyimide film.

6. Injection molding method of a ball valve according to any one of claims 1-5, characterized in that, The heat insulation paper is pasted on the ball core by using glue with a temperature resistance greater than or equal to 250 DEG C.

7. The ball valve injection molding method of claim 6, wherein, The heat insulation paper is pasted on the ball core by using temperature-resistant epoxy glue or phenolic resin glue.

8. The ball valve injection molding method according to any one of claims 1 to 7, characterized in that, After the valve shell is formed, the valve shell with the ball core is ejected, the ball core is rotated to a position where the heat insulation paper is aligned with the water inlet or water outlet of the valve shell, and the heat insulation paper is torn off.

9. The ball valve injection molding method of claim 8, wherein, After the valve shell is ejected, the ball core is immediately rotated and the heat insulation paper is torn off.

10. The ball valve injection molding method according to any one of claims 1 to 9, characterized in that, The method for injection molding the ball core comprises the following steps: primary injection molding an inner layer ball; secondary injection molding an outer layer ball on the inner layer ball to obtain a standard ball core.

11. The ball valve injection molding method of claim 10, wherein, The outer diameter of the inner layer ball is smaller than the outer diameter of the standard ball core.

12. The ball valve injection molding method of claim 10, wherein, The radial thickness of the outer layer ball is 1.5mm-2mm.

13. Injection molding method of a ball valve according to any one of claims 10-12, characterized in that, The outer surface of the inner layer ball is provided with a positioning part configured to cooperate with the outer layer ball.

14. The ball valve injection molding method of claim 13, wherein, The positioning part is in a circular, square, oval, olive or arc strip shape.

15. The ball valve injection molding method according to any one of claims 10-12, wherein, The outer surface of the inner layer ball is provided with a plurality of positioning parts, and the plurality of positioning parts are distributed in a lattice.

16. The ball valve injection molding method according to any one of claims 10 to 15, characterized in that, When the outer layer ball is secondarily injection molded, the mold is preheated to 60-70 DEG C.

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