Stress cone forming method

Abstract

This application provides a stress cone molding method, including the following steps: First vulcanization: injecting a first rubber material into a first mold, causing the first rubber material to vulcanize and form a first part of the stress cone; First polishing: fitting the first part onto a first tooling shaft, driving the first tooling shaft to rotate axially, so as to polish at least a portion of the outer surface of the first part using a polishing component to form a frosted surface; Second vulcanization: installing the first part, after the first polishing, into a second mold, using the first part as the skeleton constituting the cavity of the second mold, with the frosted surface of the first part facing the cavity of the second mold; injecting a second rubber material into the cavity of the second mold, causing the second rubber material to vulcanize and form a second part of the stress cone, the second part being connected to the first part through the frosted surface. The stress cone molding method provided by this application aims to improve the electrical performance and reliability of the stress cone.

Description

Technical Field

[0001] This application belongs to the field of cable processing technology, specifically relating to a stress cone forming method. Background Technology

[0002] As a core component of high-voltage cable assemblies, the stress cone improves the electric field distribution at the ends of the metal sheath, reduces the electric field strength at the edges of the metal sheath, and provides shock absorption and energy dissipation. Its structure is as follows: Figure 1 As shown, it is composed of semi-conductive EPDM rubber 201 and insulating EPDM rubber 202.

[0003] According to electrical performance requirements, the curved interface between the insulating and conductive adhesives within the stress cone's inner hole should be tightly bonded with good adhesive strength. No gaps are allowed between the interfaces, and the inner hole's bonding surface should be smooth and stepless. The condition of the bonding surface affects electrical performance. However, in related technologies, steps are commonly found at the inner hole bonding point during stress cone molding, and the molding process cannot precisely control the rubber material position. After the second vulcanization molding, the rubber skeleton is prone to deformation, causing the stress cone to deviate from its original design, thus affecting the stress cone's electrical performance and reliability. Summary of the Invention

[0004] The technical problem to be solved by this application is to provide a stress cone forming method with better electrical performance and higher reliability.

[0005] In a first aspect, embodiments of this application provide a stress cone forming method, comprising the following steps:

[0006] Step S1: First vulcanization, inject the first rubber material into the first mold, and vulcanize the first rubber material into the first part of the stress cone;

[0007] Step S2: First grinding: The first part is fitted onto the first tooling shaft, and the first tooling shaft is driven to rotate axially so as to use the grinding component to grind at least part of the outer surface of the first part to form a frosted surface.

[0008] Step S3: Second vulcanization. The first part, which has been polished for the first time, is installed into the second mold to use the first part as the skeleton of the cavity of the second mold. The frosted surface of the first part faces the cavity of the second mold. The second rubber material is injected into the cavity of the second mold, so that the second rubber material is vulcanized and formed into the second part of the stress cone. The second part is connected to the first part through the frosted surface.

[0009] According to an embodiment of the first aspect of this application, in the first vulcanization, the cavity of the first mold may be provided with an extension space, the extension space being disposed in the cavity of the first mold corresponding to the end of the first part near the second part;

[0010] The first vulcanization process also includes:

[0011] Step S15: Trimming, the first part is fitted onto the first tooling shaft, and the first tooling shaft is driven to rotate axially so as to use the cutting element to remove the part of the first part corresponding to the extension space.

[0012] According to an embodiment of the first aspect of this application, the first tooling shaft includes a body portion and a limiting portion. The diameter of the body portion is smaller than the diameter of the limiting portion. The body portion has a radially recessed relief groove, and the distance between the relief groove and the limiting portion is equal to the axial dimension of the first portion.

[0013] In the trimming step, the end of the first part that is away from the second part is first fitted into the body part, and the first part is pushed axially so that the end of the first part that is away from the second part abuts against the limiting part, and the cutting part is located in the clearance groove.

[0014] According to an embodiment of the first aspect of this application, the axial dimension of the clearance groove is D1, then 2mm≦D1≦5mm; the radial dimension of the clearance groove is D2, then 0.6mm≦D2≦1.5mm.

[0015] According to an embodiment of the first aspect of this application, the second vulcanization further includes the following step:

[0016] Step S4: Second grinding. The stress cone that has undergone the second vulcanization molding is fitted onto the second tooling shaft, and the second tooling shaft is driven to rotate so as to use the grinding component to grind the outer surface of the stress cone corresponding to the connection between the first part and the second part.

[0017] According to an embodiment of the first aspect of this application, in the second grinding, the grinding component is an external cylindrical grinding machine, which grinds the outer surface of the stress cone towards the axial direction by 0.2 mm to 0.5 mm.

[0018] According to an embodiment of the first aspect of this application, when the stress cone, which has undergone a second vulcanization molding, is sleeved on the second tooling shaft, the diameter of the stress cone and the second tooling shaft is controlled to be 1 mm to 3 mm of interference, and the rotational speed of the second tooling shaft is R1≦3000r / min.

[0019] According to an embodiment of the first aspect of this application, during the first polishing, the surface roughness of the frosted surface is controlled to be between 1 μm and 4 μm.

[0020] According to one embodiment of the first aspect of this application, during the first polishing, the surface roughness of the frosted surface is controlled to be 1.5 μm to 2 μm.

[0021] According to an embodiment of the first aspect of this application, when the first part is sleeved on the first tooling shaft, the diameter of the first part and the first tooling shaft are controlled to be interfered by 1mm to 3mm, and the rotational speed of the first tooling shaft is R1≦3000r / min.

[0022] The beneficial effect of this application is that after the first part of the stress cone is formed in the first vulcanization process, the first part is taken out and fitted onto the first tooling shaft for the first grinding, so that at least part of the surface of the first part becomes a frosted surface. In the subsequent second part forming process, the contact area between the rubber material of the second part and the first part is increased, the bonding strength between the second part and the first part is increased, the structural consistency of the two parts of the stress cone is improved, and thus the electrical performance stability and reliability of the product are improved. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a structural diagram of a stress cone formed using the stress cone forming method provided in the first aspect of this application;

[0025] Figure 2 This is a flowchart of the stress cone forming method provided in the first aspect embodiment of this application;

[0026] Figure 3 This is a schematic diagram of the structure of the first tooling shaft used in the stress cone forming method provided in the first aspect embodiment of this application;

[0027] Figure 4 yes Figure 3 An enlarged view of part A of the first tooling shaft shown;

[0028] Figure 5 This is a schematic diagram comparing the pressure at various positions on the interference surface when there is a 1mm interference between the stress cone and the second tooling shaft in the stress cone forming method provided in the first aspect embodiment of this application.

[0029] In the figure, 200 is the stress cone; 201 is the semi-conductive EPDM rubber; 202 is the insulating EPDM rubber; 10 is the first tooling shaft; 11 is the main body; 111 is the clearance groove; and 12 is the limiting part. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0032] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0033] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0034] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0035] In this application, "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more (including two), and "multiple pieces" refers to two or more (including two).

[0036] Figure 2 This is a flowchart of the stress cone forming method provided in the first aspect embodiment of this application; Figure 3 This is a schematic diagram of the structure of the first tooling shaft used in the stress cone forming method provided in the first aspect embodiment of this application; Figure 4 yes Figure 3 An enlarged view of part A of the first tooling shaft shown; Figure 5 This is a schematic diagram comparing the pressure at various positions on the interference surface when there is a 1mm interference between the stress cone and the second tooling shaft in the stress cone forming method provided in the first aspect embodiment of this application.

[0037] like Figures 2 to 5 As shown in the figure, this application provides a stress cone forming method, which includes the following steps:

[0038] Step S1: First vulcanization, inject the first rubber material into the first mold, and vulcanize the first rubber material into the first part of the stress cone 200.

[0039] The purpose of this step is to form the first part of the stress cone 200, wherein, in these embodiments of the present application, the first part can be either the aforementioned semi-conductive EPDM rubber 201 or the insulating EPDM rubber 202.

[0040] In these embodiments of the present application, the injection of the first rubber material into the first mold may be carried out by designing the cavity shape of the first mold to be the same as the semi-conductive EPDM rubber 201 part or the insulating EPDM rubber 202 part of the stress cone 200, and injecting the corresponding rubber material into the cavity of the first mold through the injection port of the first mold.

[0041] For example, in these embodiments of this application, the insulating EPDM rubber 202 portion of the stress cone 200 can be formed using a first mold. In this way, the cavity of the first mold can be set to be the same as the insulating EPDM rubber 202 portion, and the insulating EPDM rubber 202 raw material can be injected into the cavity of the first mold through the injection port.

[0042] In these embodiments of this application, the first rubber raw material is vulcanized and molded into the first part of the stress cone 200. A possible implementation is to vulcanize and mold the first rubber raw material by means of hot vulcanization, so that the first rubber raw material achieves positive vulcanization during the heating process and obtains better overall performance.

[0043] In some embodiments of this application, the first rubber raw material may be vulcanized by cold vulcanization or room temperature vulcanization, which can be selected according to the actual situation.

[0044] Step S2: First grinding, the first part is fitted onto the first tooling shaft 10, and the first tooling shaft 10 is driven to rotate axially so as to use the grinding component (not shown) to grind at least part of the outer surface of the first part to form a frosted surface.

[0045] In these embodiments of this application, the first part is sleeved on the first tooling shaft 10, and the first tooling shaft 10 is driven to rotate axially. A possible implementation is to sleeve the first part along the axial direction of the first tooling shaft 10, so that the first part can rotate with the axial rotation of the first tooling shaft 10. It should be noted that in these embodiments of this application, after the first part is sleeved on the first tooling shaft 10, the friction between the inner wall of the first part and the first tooling shaft 10 can be used to reduce the probability of relative movement between the first part and the first tooling shaft 10 in the circumferential direction; simultaneously, a limiting member can be placed on the first tooling shaft 10 to restrict the relative movement between the first part and the first tooling shaft 10 in the axial direction.

[0046] The polishing component can be sandpaper, which is used to polish at least a portion of the outer surface of the first part to form a uniformly rough abrasive surface; in some embodiments, the polishing component can also be corundum, silica sand, garnet powder, etc., to mechanically or manually polish the outer surface of the first part, which can also be used to form a uniformly rough abrasive surface.

[0047] In these embodiments of this application, grinding at least a portion of the outer surface of the first part using a grinding member refers to grinding the surface of the first part that is used to connect with the second part in a subsequent step, so that the surface of the first part used to connect with the second part forms a frosted surface. In this way, during the subsequent vulcanization molding of the second part, the rubber raw material of the second part can be sufficiently impregnated on the frosted surface, increasing the bonding area between the second part and the first part, thereby improving the connection strength between the second part and the first part.

[0048] Step S3: Second vulcanization. The first part, which has been polished for the first time, is installed into the second mold to use the first part as the skeleton of the cavity of the second mold. The frosted surface of the first part faces the cavity of the second mold. The second rubber material is injected into the cavity of the second mold, so that the second rubber material is vulcanized and formed into the second part of the stress cone. The second part is connected to the first part through the frosted surface.

[0049] The first part, after the first polishing, is installed into the second mold to serve as the skeleton of the cavity of the second mold. The frosted surface of the first part faces the cavity of the second mold. This means that in this step, the first part after polishing in step S2 is used as the mold skeleton for forming the second part, so as to cooperate with other structures of the second mold to form the cavity of the second part.

[0050] With the frosted surface of the first part facing the cavity of the second mold, the second rubber material can fully wet the frosted surface when it is injected into the cavity of the second mold. This results in a larger contact area with the first part during the vulcanization process, which in turn increases the contact area between the second and first parts, increases the bonding strength between the two parts, improves the structural consistency of the two parts of the stress cone, and ultimately improves the electrical performance stability and reliability of the stress cone 200.

[0051] In these embodiments of the present application, a possible implementation method is to inject the second rubber material into the cavity of the second mold. The injection hole of the second mold is designed as a symmetrical double-hole injection to increase the injection rate of the second rubber material during injection, so that the second rubber material can quickly fill the cavity of the second mold. The symmetrical double-hole injection can optimize the distribution of the second rubber material in the cavity of the second mold throughout the injection process, making the distribution of the second rubber material along the axial direction of the stress cone 200 more uniform, which is beneficial to improving the consistency of the vulcanization of the second rubber material.

[0052] For example, in these embodiments of the present application, the injection holes of the second mold can be set symmetrically along the axis of the cavity of the second mold, and the two injection holes and the axis of the cavity of the second mold are in the same straight line in the radial direction, so as to maximize the uniform vulcanization degree of the second rubber raw material injected into the cavity of the second mold at all positions in the axial direction, so as to further improve the stress cone 200.

[0053] Meanwhile, during the injection process, a low-pressure injection process can be used to reduce the impact on the first part, which serves as the skeleton, when the second rubber material is injected into the cavity of the second mold. This reduces the probability of deformation of the rubber skeleton structure of the first part due to excessive stamping, and further improves the stability of the second part structure molding.

[0054] For example, in these embodiments of this application, the low-pressure injection pressure can be set to less than 40 bar to reduce the probability of deformation of the rubber skeleton structure of the first part due to excessive stamping, and further improve the stability of the second part structure molding.

[0055] After the first part of the stress cone 200 is formed in the first vulcanization process, the first part is taken out and fitted onto the first tooling shaft 10 for the first grinding, so that at least part of the surface of the first part becomes a frosted surface. In the subsequent second part forming process, the contact area between the rubber material of the second part and the first part is increased, the bonding strength between the second part and the first part is increased, the structural consistency of the two parts of the stress cone is improved, and thus the electrical performance stability and reliability of the product are improved.

[0056] Similar to the vulcanization method in the first part, in these embodiments of this application, the second rubber raw material can also be vulcanized and molded by hot vulcanization so that the second rubber raw material can achieve positive vulcanization during the heating process and obtain better overall performance.

[0057] According to an embodiment of the first aspect of this application, in the first vulcanization, the cavity of the first mold may be provided with an extension space, the extension space being disposed in the cavity of the first mold corresponding to the end of the first part near the second part;

[0058] The first vulcanization process also includes:

[0059] Step S15: Trimming, the first part is fitted onto the first tooling shaft 10, and the first tooling shaft 10 is driven to rotate axially so as to use the cutting element to cut off the part of the first part corresponding to the extension space.

[0060] In these embodiments of this application, by setting the cavity of the first mold to have an extension space, it means that the cavity of the first mold is larger than the molding space required for the first part. In this way, when the first part is molded, the excess part can be molded at the position corresponding to the extension space.

[0061] For example, in the embodiment where the first part is the insulating EPDM rubber 202 part in the first vulcanization step of this application, since the connection surface between the first part and the second part is curved and the thickness is small at the end near the semiconductive EPDM rubber 201 part, if the cavity of the first mold is directly set to be the same shape as the first part, after the first rubber raw material is injected, air pockets are easily generated in the cavity of the first mold at the position where the thickness is small at the end of the insulating EPDM rubber 202 part near the semiconductive EPDM rubber 201 part, which leads to incomplete structural forming of the first part.

[0062] Based on this, in these embodiments of the present application, the aforementioned extension space can be provided at a position in the cavity of the first mold corresponding to the end of the insulating EPDM 202 portion near the semiconductive EPDM 201 portion where the thickness is smaller. This allows for the formation of an excess portion at the end of the first portion corresponding to the second portion during the first vulcanization, and the removal of this excess portion in subsequent steps. This reduces the probability of air pockets forming at the end of the first portion near the second portion after the first rubber material is injected into the cavity of the first mold. Combined with the subsequent step of removing the excess portion, this improves the structural integrity of the first portion and enhances the stability and reliability of the electrical performance of the stress cone 200 finished product.

[0063] Step S15 and step S2 are parallel steps, that is, in some embodiments of this application, steps S15 and / or S2 may be included to select the molding step according to the needs of different products.

[0064] In step S15, the first part is fitted onto the first tooling shaft 10, and the first tooling shaft 10 is driven to rotate axially, so that the portion of the first part corresponding to the extended space is removed using the cutting member. In these embodiments of this application, by driving the first tooling shaft 10 to rotate axially, thereby causing the first part to rotate, after the position of the cutting member along the axial direction of the first tooling shaft 10 is set, it is only necessary to adjust the distance between the cutting member and the first tooling shaft 10 to use the cutting member to perform circumferential cutting on the first part, so as to remove the excess portion of the first part.

[0065] Using a cutting tool to remove the portion corresponding to the extended space in the first part refers to using a cutting tool to remove the excess portion formed during the first vulcanization. Exemplarily, in these embodiments of this application, the cutting tool may be, but is not limited to, a lathe tool, a planer tool, a milling cutter, an external surface broach, and a file, etc.

[0066] In these embodiments of the present application, by setting the cavity of the first mold to have an extension space and setting the trimming step in step S15, an excess part is set at the end of the first part that is connected to the second part in the first vulcanization step in step S1, and the excess part is removed in the subsequent step S15. On the one hand, the structural consistency of different first parts after molding can be improved, and on the other hand, the probability of bubble defects appearing at the end of the first part near the second part can be reduced, thereby improving the molding yield of the stress cone 200 and improving the electrical performance of the stress cone 200.

[0067] According to an embodiment of the first aspect of this application, the first tooling shaft 10 includes a body portion 11 and a limiting portion 12. The diameter of the body portion 11 is smaller than the diameter of the limiting portion 12. The body portion 11 has a radially recessed relief groove 111, and the distance between the relief groove 111 and the limiting portion 12 is equal to the axial dimension of the first portion.

[0068] In the trimming step, the end of the first part away from the second part is first fitted into the body part 11, and the first part is pushed axially so that the end of the first part away from the second part abuts against the limiting part 12, and the cutting part is located at the relief groove 111.

[0069] In these embodiments of this application, the first tooling shaft 10 can be a rotating shaft mounted on a machine tool. The first tooling shaft 10 includes a body portion 11 and a limiting portion 12, where the diameter of the body portion 11 is smaller than the diameter of the limiting portion 12. This means that the body portion 11 and the limiting portion 12 are coaxially arranged round rods, with one axial end of the body portion 11 connected to the limiting portion 12, and the diameter of the body portion 11 is smaller than the diameter of the limiting portion 12. In this way, in the trimming step of S15, the end of the body portion 11 that does not require trimming can be inserted into the body portion 11 away from the limiting portion 12, and the first portion can be pushed axially along the body portion 11 so that the first portion abuts against the end of the limiting portion 12 near the body portion 11, thereby limiting the axial displacement of the first portion. This ensures that the positions of different first portions in each trimming step remain relatively uniform, resulting in higher dimensional consistency among the different first portions after trimming.

[0070] The distance between the clearance groove 111 and the limiting part 12 is equal to the axial dimension of the first part. The clearance groove 111 and the limiting part 12 are used to limit the axial dimension of the first part. In the trimming step, the excess part of the first part corresponding to the extension space can be cut off by simply aligning the position of the cutting part with the clearance groove 111, thereby improving the structural consistency of different first parts.

[0071] In these embodiments of this application, a relief groove 111 is provided that is radially recessed along the body portion 11 so as to avoid the cutting part during the trimming process, thereby reducing the risk of the cutting part damaging the first tooling shaft 10. This avoids the risk of further damage to the first part after the first tooling shaft 10 is damaged, improves the structural integrity of the first part, and further improves the electrical performance and reliability of the stress cone 200 after molding.

[0072] According to an embodiment of the first aspect of this application, the axial dimension of the clearance groove 111 is D1, then 2mm≦D1≦5mm; the radial dimension of the clearance groove 111 is D2, then 0.6mm≦D2≦1.5mm.

[0073] In these embodiments of the present application, the value of the axial dimension D1 of the clearance groove 111 is related to the size of the cutting element used for circumferential cutting of the first part in order to improve the cutting effect of the cutting element. In these embodiments of the present application, the value of D1 may be set to 2.5mm, 3mm, 3.5mm, 4mm or 4.5mm.

[0074] The radial dimension of the clearance groove 111 is set to D2, and the value of D2 is the depth of the clearance groove 111. In these embodiments of this application, by setting the value of D2 to 0.6mm≦D2≦1.5mm, the probability of the cutting part cutting the body part 11 when circumferentially cutting the first part can be reduced, the risk of the body part 11 being cut and scratched by the cutting part can be reduced, and the risk of the damaged surface of the body part 11 causing damage to the first part during the next trimming can be avoided.

[0075] For example, in these embodiments of this application, the value of D2 may be set to 0.8mm, 1.0mm or 1.2mm.

[0076] According to an embodiment of the first aspect of this application, the second vulcanization further includes the following step:

[0077] Step S4: Second grinding. The stress cone that has undergone the second vulcanization molding is fitted onto the second tooling shaft, and the second tooling shaft is driven to rotate so as to use the grinding component to grind the outer surface of the stress cone corresponding to the connection between the first part and the second part.

[0078] The second tooling shaft is similar to the first tooling shaft, and can also be a rotating shaft on a machining tool. Its function is similar to that of the first tooling shaft. It is used to supply the force cone 200 to be fitted. By utilizing the friction between the outer surface of the second tooling shaft and the inner surface of the stress cone 200, the stress cone 200 is driven to rotate with the second tooling shaft when the second tooling shaft rotates axially.

[0079] In these embodiments of this application, a grinding component is used to grind the outer surface of the stress cone 200 at the connection between the first part and the second part. The purpose is that, since the stress cone 200 is a structure that undergoes two vulcanization moldings, during the second vulcanization molding of the second part, the position where the second rubber raw material flows into the cavity of the second mold can be set at the connection between the outer surfaces of the first part and the second part. At this time, after the second vulcanization molding, bubble defects are also likely to form at the connection between the outer surfaces of the first part and the second part. Therefore, by setting the second grinding step in step S4, the outer surface defects that may exist during the molding process can be eliminated, thereby improving the electrical performance and reliability of the stress cone 200.

[0080] According to an embodiment of the first aspect of this application, in the second grinding, the grinding component is an external cylindrical grinding machine, which grinds the outer surface of the stress cone towards the axial direction by 0.2 mm to 0.5 mm.

[0081] In these embodiments of this application, the outer surface of the stress cone 200 is ground to 0.2 mm to 0.5 mm in the axial direction by a defined grinding member. That is, the thickness of the outer surface of the stress cone 200 to the axis is ground to 0.2 mm to 0.5 mm by the grinding member. This is to improve the smoothness of the outer surface while minimizing the impact on the performance of the stress cone 200, so that the first part and the second part can smoothly transition at the connection of the outer surface, thereby further improving the product yield of the stress cone 200 molding.

[0082] According to an embodiment of the first aspect of this application, when the stress cone 200, which has undergone a second vulcanization molding, is fitted onto the second tooling shaft, the diameter of the stress cone 200 and the second tooling shaft is controlled to be 1 mm to 3 mm over-interference, and the rotational speed of the second tooling shaft is R1≦3000r / min.

[0083] In these embodiments of the present application, by controlling the diameter interference between the stress cone 200 and the second tooling shaft to be 1 mm to 3 mm, and limiting the rotational speed R1 of the second tooling shaft to 3000 r / min, the stability of the stress cone 200 rotating with the second tooling shaft is improved, and the situation of the stress cone 200 sliding with the second tooling shaft along the rotation direction is reduced.

[0084] For example, in these embodiments of this application, simulation calculations show that when the diameter of the stress cone 200 is 1 mm over the second tooling shaft, the interference force is 1307 N, which is greater than the centripetal force of 997 N required at the maximum speed of 3000 r / min. This ensures that the stress cone 200 rotates with the second tooling shaft when the second tooling shaft rotates axially. However, when the diameter of the stress cone 200 is more than 3 mm over the second tooling shaft, the interference force between the stress cone 200 and the second tooling shaft becomes too large, making it difficult to move and adjust the position of the stress cone 200 along the axial direction of the second tooling shaft.

[0085] It should be noted that please refer to the following for details. Figure 5 As shown in the figure, after the stress cone 200 is fitted into the second tooling shaft, the stress between the stress cone 200 and the second tooling shaft is mainly concentrated in the middle position, while the stress between the two ends of the stress cone 200 along the axial direction and the second tooling shaft is relatively small. Therefore, when the diameter interference between the stress cone 200 and the second tooling shaft is 1mm to 3mm, the stability of the stress cone 200 and the second tooling shaft in the rotation direction can be improved, and the slippage between the stress cone 200 and the second tooling shaft in the rotation direction can be reduced. In addition, the stress in the axial direction between the stress cone 200 and the second tooling shaft is mainly concentrated in the middle of the stress cone 200, so that the friction between the stress cone 200 and the second tooling shaft in the axial direction is not too large, making it easy to move the stress cone 200 in the axial direction of the second tooling shaft to adjust the position of the stress cone 200.

[0086] According to an embodiment of the first aspect of this application, during the first polishing, the surface roughness of the frosted surface is controlled to be between 1 μm and 4 μm.

[0087] According to one embodiment of the first aspect of this application, during the first polishing, the surface roughness of the frosted surface is controlled to be 1.5 μm to 2 μm.

[0088] For example, in these embodiments of the present application, the surface roughness of the frosted surface can be controlled to be 1.2μm, 1.8μm, 2.5μm, 3μm or 3.5μm.

[0089] According to an embodiment of the first aspect of this application, when the first part is sleeved on the first tooling shaft 10, the diameter of the first part and the first tooling shaft 10 is controlled to be 1 mm to 3 mm of interference, and the rotational speed of the first tooling shaft 10 is R1≦3000r / min.

[0090] In these embodiments of this application, the function of this embodiment is the same as that of the aforementioned interference fit between the stress cone 200 and the second tooling shaft of 1mm to 3mm, the purpose of which is to improve the stability of the first part rotating with the first tooling shaft and reduce the possibility of the first part sliding with the first tooling shaft along the rotation direction. At the same time, in these embodiments of this application, by limiting the diameter interference fit between the first part and the first tooling shaft of 1mm to 3mm, the probability of the first part moving along the axial direction of the first tooling shaft can also be reduced, thereby improving the efficiency and reliability of the first grinding in step S2 and the efficiency and reliability of the trimming in step S4.

[0091] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of protection of this application is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of one or more embodiments of this application as described above, which are not provided in detail for the sake of brevity.

[0092] One or more embodiments in this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments in this application should be included within the protection scope of this application.

Claims

1. A method for forming a stress cone, characterized in that, Includes the following steps: In the first vulcanization, the first rubber material is injected into the first mold, so that the first rubber material is vulcanized and formed into the first part of the stress cone; In the first grinding, the first part is fitted onto the first tooling shaft, and the first tooling shaft is driven to rotate axially so as to use the grinding component to grind at least a portion of the outer surface of the first part to form a frosted surface. In the first vulcanization, the cavity of the first mold has an extension space, which is located at the end of the cavity of the first mold corresponding to the first part near the second part; after the first vulcanization, the process further includes: trimming, fitting the first part onto the first tooling shaft, driving the first tooling shaft to rotate axially, so as to use a cutting tool to cut off the portion of the first part corresponding to the extension space. The first tooling shaft includes a body portion and a limiting portion. The diameter of the body portion is smaller than the diameter of the limiting portion. The body portion has a radially recessed clearance groove, and the distance between the clearance groove and the limiting portion is equal to the axial dimension of the first portion. In the trimming step, the end of the first part away from the second part is first fitted into the body part, and the first part is pushed axially so that the end of the first part away from the second part abuts against the limiting part, and the cutting part is located at the clearance groove. In the second vulcanization, the first part, which has been polished in the first step, is installed into the second mold so that the first part serves as the skeleton of the cavity of the second mold, and the frosted surface of the first part faces the cavity of the second mold. The second rubber material is injected into the cavity of the second mold, so that the second rubber material is vulcanized and formed into the second part of the stress cone. The second part is connected to the first part through the frosted surface.

2. The stress cone forming method according to claim 1, characterized in that, If the axial dimension of the clearance groove is D1, then 2mm≦D1≦5mm; if the radial dimension of the clearance groove is D2, then 0.6mm≦D2≦1.5mm.

3. The stress cone forming method according to claim 1, characterized in that, The second vulcanization process also includes the following steps: In the second grinding process, the stress cone, which has undergone the second vulcanization molding, is fitted onto the second tooling shaft, and the second tooling shaft is driven to rotate so that the outer surface of the stress cone, corresponding to the connection between the first part and the second part, is ground by the grinding component.

4. The stress cone forming method according to claim 3, characterized in that, In the second grinding process, the grinding component is an external cylindrical grinding machine, which is used to grind the outer surface of the stress cone towards the axial direction by 0.2 mm to 0.5 mm.

5. The stress cone forming method according to claim 3, characterized in that, When the stress cone, which has undergone a second vulcanization molding, is fitted onto the second tooling shaft, the diameter of the stress cone and the second tooling shaft is controlled to be 1mm to 3mm over-interference, and the rotational speed of the second tooling shaft is R1≦3000r / min.

6. The stress cone forming method according to claim 1, characterized in that, In the first polishing process, the surface roughness of the frosted surface is controlled to be between 1 μm and 4 μm.

7. The stress cone forming method according to claim 6, characterized in that, In the first polishing process, the surface roughness of the frosted surface is controlled to be between 1.5 μm and 2 μm.

8. The stress cone forming method according to any one of claims 1 to 7, characterized in that, When the first part is fitted onto the first tooling shaft, the diameter of the first part and the first tooling shaft are controlled to be 1mm to 3mm over-interference, and the rotational speed of the first tooling shaft is R1≦3000r / min.

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