Heavy-current connector

Abstract

The utility model discloses a heavy-current connector, which relates to the technical field of connectors and comprises a base, a plurality of terminal modules and two inner screw hole metal tubes which are integrally formed by insulating materials. The base is composed of a main body part and a socket part, the main body part is provided with a through hole and a rear pipeline, the socket part is provided with at least five front pipelines arranged side by side, and the pipe wall is provided with a guide slope, a positioning groove and a shallow groove structure so as to optimize terminal positioning and reduce plugging interference. The terminal module comprises a metal terminal, an insulating cap and a retaining ring, the inner screw hole metal tube provides a fixing function, the structural stability and the electrical reliability are improved, and the terminal module is suitable for a high-current application scene.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of connector, especially relates to a large current connector. BACKGROUND

[0002] In the power management of servers and other high-power electronic devices, the design of the connector is crucial to ensure stable power transmission. The existing large current connectors generally have problems such as insufficient structural strength, unstable terminal fixation, and poor contact, which can cause overheating of the device, increase contact loss, and even affect the normal operation of the server in a high current environment.

[0003] To solve the above problems, some existing technologies try to improve the terminal structure and enhance the connector fixation strength to enhance performance. However, these improvements often cannot balance the structural strength and the stability of terminal positioning, resulting in complex assembly and increased cost. In addition, the existing connector is prone to plug interference during the docking process of the terminal and the female connector due to tolerance problems, which affects the plug efficiency and life of the terminal.

[0004] Therefore, it is urgent to provide an improved connector design that can improve the stability of terminal fixation, reduce plug interference, and enhance the structural strength of the connector while maintaining the size of the connector to meet the use requirements of high-current devices such as servers. SUMMARY

[0005] The main purpose of the utility model is to provide a large current connector, which can improve the stability of terminal fixation, reduce plug interference, and enhance the structural strength of the connector without increasing the size of the connector to meet the use requirements of high-current devices such as servers.

[0006] To achieve the above object, the utility model provides a large current connector for server power supply, the large current connector includes a base, a plurality of terminal module and two inner thread metal pipe, the base includes a main part and a socket part, the maximum height of main part along the height direction is between 12mm to 26mm, the main part includes a back pipeline, both sides of main part are equipped with a through hole extending along the front and back direction respectively, the maximum height of socket part along the height direction is between 11mm to 25mm, the maximum height of socket part is less than the maximum height of main part, socket part is connected in the front of main part, socket part includes at least five front pipelines arranged side by side, every front pipeline is communicated with corresponding back pipeline and extends from back to front, both sides of socket part are equipped with a barb respectively, the front end surface of pipe wall between every two adjacent front pipelines is equipped with a transverse groove extending along the width direction and communicated with two front pipelines, every front pipeline includes a positioning pipe wall on the upside, the positioning pipe wall is equipped with a positioning groove extending along the front and back direction, the maximum depth along the height direction is between 0.5mm to 1.4mm, a plurality of terminal module is embedded in front pipeline and corresponding back pipeline respectively, every terminal module includes a metal terminal, an insulating cap fixed on the top of metal terminal and a C-shaped stop ring buckled on the surface of metal terminal, the stop ring is used to resist the base to prevent every corresponding metal terminal from withdrawing back to the base, the metal terminal has a foot, the foot is cylindrical and the diameter is between 2mm and 10mm, two inner thread metal pipes are embedded in the through hole of both sides of base respectively to provide an internal thread in the through hole.

[0007] In an embodiment, the edges of the front end surfaces of the at least five front pipelines arranged side by side are respectively provided with guide slopes, and the thickness of the guide slopes is between 0.05mm and 0.5mm.

[0008] In an embodiment, the insulating cap on the top end of the metal terminal includes at least one aperture.

[0009] In an embodiment, the rear end of the stop ring is thicker than the front end.

[0010] In an embodiment, at least one of the at least five front pipelines arranged side by side has a plurality of mutually adjacent pipe walls inside, the plurality of pipe walls include at least two shallow groove pipe walls, the two shallow groove pipe walls face each other and each include a shallow groove extending along the front and back direction.

[0011] In an embodiment, the two shallow-groove pipe walls are connected by at least two planar walls and the positioning pipe walls, the depth of the shallow grooves in the height direction is between 0.05mm and 0.5mm, and the shallow grooves account for no more than 15% of the maximum thickness of the pipe wall where the shallow grooves are located.

[0012] In an embodiment, the bottoms of the shallow grooves in the two shallow-groove pipe walls are respectively curved.

[0013] In an embodiment, the socket portion includes an upwardly disposed upper coplanar surface formed by at least the pipe walls of the at least five front pipes arranged side by side and the horizontal support walls connecting between the pipe walls, and the socket portion includes a downwardly disposed lower coplanar surface formed by at least the pipe walls of the at least five front pipes arranged side by side and the horizontal support walls connecting between the pipe walls.

[0014] In an embodiment, the front end openings of each of the front pipes are respectively polygonal, and the lines of the polygonal shape do not include a circular shape.

[0015] The utility model discloses still propose a kind of high current connector, for the power supply of server, the high current connector includes a base, multiple terminal module and two internal screw hole metal pipes, the base includes a main body part and a socket portion, the main body part includes a rear pipe, the both sides of the main body part are respectively provided with a through hole extending along front-back direction;The maximum height of the socket portion along height direction is less than the maximum height of main body part, the socket portion is connected in the front of the main body part, the socket portion includes at least five front pipes arranged side by side, the front end opening of each of the front pipes is polygonal, and the lines of the polygonal shape do not include a circular shape, each of the front pipes is communicated with corresponding rear pipe and extends from rear to front, the both sides of the socket portion are respectively provided with a barb, the front end surface of the pipe wall between two adjacent front pipes is respectively provided with a transverse groove extending along width direction and communicated with two front pipes, each of the front pipes includes a positioning pipe wall located on the upper side, and the positioning pipe wall is provided with a positioning groove extending along the front-back direction;Multiple terminal module is respectively embedded in the front pipe and corresponding rear pipe, each of the terminal module includes a metal terminal, an insulating cap fixedly arranged on the top of the metal terminal and a C-shaped retaining ring buckled on the surface of the metal terminal, the retaining ring is used to resist the base to prevent each corresponding metal terminal from withdrawing the base to rear, and the metal terminal has a foot portion, and the foot portion is cylindrical;Two internal screw hole metal pipes are respectively embedded in the through hole on the both sides of the base, to provide an internal screw thread in the through hole.

[0016] The main objective of this invention is to propose an improved connector design that can enhance terminal fixing stability, reduce insertion interference, and strengthen the connector structure without increasing connector size, thereby meeting the usage requirements of high-current devices such as servers. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the overall structure of an embodiment of the high-current connector provided by this utility model;

[0019] Figure 2 for Figure 1 A schematic diagram of a high-current connector from another perspective;

[0020] Figure 3 for Figure 1 A schematic diagram of the high-current connector from the front view.

[0021] Figure 4 for Figure 1 A schematic diagram of each terminal module of the high-current connector in the image;

[0022] Figure 5 for Figure 4 Schematic diagram of the component assembly of the mid-terminal module;

[0023] Figure 6 For along Figure 1 A cross-sectional view of an embodiment of a high-current connector;

[0024] Figure 7 for Figure 1 A magnified diagram of the forward-looking perspective.

[0025] Explanation of icon numbers:

[0026] A, large current connector; D, length direction; H, height direction; W, width direction; L1, maximum height of the socket part; L2, maximum height of the main body part; L3, depth of the shallow groove; L4, thickness of the guide slope; L5, maximum thickness of the shallow groove wall; L6, maximum thickness of the upper wall; L7, maximum height of the positioning groove; L9, length of the accommodating groove; L10, diameter of the foot cylinder; 10, base; 11, main body part; 111, rear pipe; 111A, pipe wall; 112, through hole; 113, front wall; 114, rear wall; 115, stepped platform; 12, socket part; 121, front pipe; 121A, positioning pipe wall; 121B, positioning groove; 121C, front end opening; 121D, bottom wall; 122, inverted hook; 123, pipe wall; 123A, shallow groove wall; 123B, shallow groove; 123C, flat wall; 123D, bottom curved surface; 123E, air hole; 124, front end face; 124A, transverse groove; 124B, guide slope; 125, horizontal support wall; 126, upper coplanar surface; 127, lower coplanar surface; 20, terminal module; 21, metal terminal; 211, head; 211A, annular inclined shoulder; 211B, top surface; 211C, protrusion; 212, body; 213, waist; 213A, front protruding ring; 213B, middle protruding ring; 213C, rear protruding ring; 213D, accommodating groove; 213E, rough surface; 214, foot; 22, insulating cap; 22A, opening; 23, stop ring; 23A, front end; 23B, rear end; 30, internally threaded metal pipe; 40, fixing member.

[0027] The realization, functional features and advantages of the present application will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0029] It should be noted that if the present application embodiments involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship, movement condition, etc. between the components in a certain posture, and if the certain posture changes, the directional indications also change accordingly.

[0030] In addition, if the description of "first", "second" and the like is involved in the embodiments of the present application, the description of "first", "second" and the like is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can be explicitly or implicitly included at least one of the features. In addition, if "and / or" or "and / or" appears throughout the text, it means that the three parallel schemes are included, for example, "A and / or B" includes A scheme, or B scheme, or A and B scheme. If the present application refers to "A" containing "B", unless explicitly excluded or not allowed by the context, the inclusion means that A contains one or more B. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope required by the present application.

[0031] In the specification, when two values are referred to as "approximately the same", the difference between the two values is less than or equal to 0.05 of the larger value. When two values are referred to as "actually the same" or "the same", the difference between the two values is less than or equal to 0.01 of the larger value.

[0032] It should be noted that the drawings of the present application are drawn in true proportion, and the size proportion and relative position of each element should be listed as part of the disclosed content.

[0033] The present application provides a large current connector for powering a server. By the following design, the terminal can be stably fixed to each connector set without significantly increasing the size, and the device can operate properly.

[0034] The design of the large current connector of the present application will be described below with an embodiment. The connector set is composed of two matched connectors, usually, the end of the male connector is connected with the end of the cable, and the large current connector is fixed to the cabinet. In application, the user can insert the male connector at the end of the wire harness into the large current connector of the server to connect the two.

[0035] The design of the large current connector is described below. See Figure 1 , Figure 2 and Figure 6 In this example, the large current connector A mainly includes a base 10, a plurality of terminal modules 20, an internal threaded metal pipe 30 and a fixing member 40.

[0036] The design of the base 10 is described below. See Figure 1The base 10 is formed by an injection molding process from an insulating material and is formed in one piece. The base 10 can be roughly divided into a socket portion 12 for plugging with a male connector and a main body portion 11 connected thereto.

[0037] See Figure 1 The maximum height of the socket portion 12 in the height direction H is referred to as the socket maximum height LI and is about 13 mm. The left and right sides of the socket portion 12 each include a barb 122. A plurality of front channels 121, also referred to as receiving channels, are arranged side by side between the two barbs 122 and are used to receive terminal modules 20. The socket maximum height LI can be between 11 and 25 mm if desired.

[0038] See Figure 1 In this example, the inner side of each front channel 121 includes eight adjacent and substantially planar channel walls 123, so that the inner contour of the front channel 121 is substantially a regular octagonal column, and the inner contour of the end face at the front end opening 121C of each front channel 121 is also substantially a regular octagon. Each adjacent channel wall 123 is provided with a transverse groove 124A extending in the width direction W at the front end face 124. See Figure 7 The maximum depth of each transverse groove 124A in the length direction D is referred to as the transverse groove depth and is about 0.6 mm. When the transverse groove depth is between 0.3 and 1 mm, the strength and alignment requirements can be better met.

[0039] In addition, see Figure 6 and Figure 7 The edge of the front end opening 121C of each front channel 121 is provided with a guide slope 124B of a certain thickness, and the center of each of the left, right, and lower three shallow groove channel walls 123A, which include planar walls 123C, is provided with a shallow groove 123B. The left and right shallow groove channel walls 123A face each other. The shallow groove 123B is a shallow curved groove, and the bottom 123D thereof is curved, so as to provide more space for the male connector to be connected, thereby reducing interference due to tolerances. The depth of the deepest part of the shallow groove 123B in the height direction D is referred to as the shallow groove depth L3, and the thickness of the guide slope 124B extending inward in the height direction D is referred to as the guide slope thickness L4. The shallow groove depth L3 can be less than or equal to the guide slope thickness L4. Alternatively, the shallow groove depth L3 is less than or equal to 15% of the shallow groove channel maximum thickness L5 of the channel wall 123 in which the shallow groove 123B is located. In this example, the guide slope thickness L4 is about 0.3 mm, the shallow groove depth L3 is 0.2 mm, the shallow groove depth L3 is recommended to be between 0.05 mm and 0.5 mm, and the shallow groove channel maximum thickness L5 of the lower channel wall 123 in which the shallow groove 123B is located is about 1.7 mm. The remaining four diagonal channel walls 123 are substantially planar walls 123C, or in other words, most of them are non-curved.

[0040] In addition, as Figure 7As shown, the maximum thickness of the upper side of the tube wall 123 of each front pipe 121 is called the upper side tube wall maximum thickness L6, which is about 2mm. In each tube wall 123, the upper side is called the positioning tube wall 121A, which is provided with a positioning groove 121B for preventing misplacement. In this example, the maximum height of the positioning groove 121B along the height direction D is called the positioning groove maximum height L7, which is about 1mm, about 50% of the thickness of the upper side of the tube wall 123. In order to maintain structural strength, it is recommended that the positioning groove maximum height L7 be controlled between 0.5mm and 1.5mm, or preferably between 30% and 70% of the upper side tube wall maximum thickness L6. In other words, the two shallow groove tube walls 123A are connected by at least two tube walls 123 including the planar wall 123C and the positioning tube wall 121A.

[0041] See Figure 6 , the positioning groove 121B extends along the length direction D all the way to the bottom wall 121D of the bottom of the front pipe 121, which is used to abut against the male connector to limit the depth of insertion. Each front pipe 121 is in communication with the outside through the vent hole 123E provided on the upper and lower sides of the tube wall 123, and the width of the vent hole 123E is the same as the maximum width of the shallow groove 123B along the width direction W.

[0042] In addition, see Figure 6 and Figure 7 , the upper and lower sides of the tube wall 123 of each front pipe 121 are connected by a horizontal support wall 125 to strengthen the structural strength of each front pipe 121, and the upper side portion, the lower side portion of the tube wall 123 of each front pipe 121 and each horizontal support wall 125 form an upper coplanar surface 126 and a lower coplanar surface 127, respectively.

[0043] See Figure 3 , the maximum height of the main body portion 11 along the height direction H is called the main body portion maximum height L2, which is about 17mm, about 30% higher than the socket portion maximum height L1. If necessary, the main body portion maximum height L2 can be between 12mm and 26mm and slightly larger than the socket portion maximum height L1.

[0044] See Figure 5 and Figure 6 , the main body portion 11 is provided with a plurality of rear pipes 111, which are in communication with the corresponding front pipes 121, and the rear pipes 111 have a front wide and rear narrow stepped structure. A stepped platform 115 is provided in the stepped structure for abutting against the outwardly expanded stop ring 23 of the metal terminal 21 to prevent the metal terminal 21 from being withdrawn backward from the base 10 and its front pipe 121. The edge of the hole of the main body portion 11 relative to the rear pipe 111 can abut against the rear protruding ring 213C of the metal terminal 21 to limit the depth of the metal terminal into the base 10.

[0045] SeeFigure 1 Each of the through holes 112 is used for embedding a metal pipe 30 with a rough outer surface, so as to provide an internal thread in the through hole 112. The metal pipe 30 is fixed on the cabinet baffle by a fixing member 40 (e.g. a screw).

[0046] See Figure 5 The following describes the design of the terminal module 20, each of which generally comprises a metal terminal 21, a retainer ring 23 and an insulating cap 22.

[0047] The metal terminal 21 is a solid copper terminal in a generally cylindrical shape, comprising a head portion 211, a body portion 212, a waist portion 213 and a foot portion 214 connected in sequence from front to back.

[0048] The head portion 211 comprises an annular inclined shoulder 211A for guiding the terminal therein when engaging with the male connector. The head portion 211 has a top surface 211B with a protrusion 211C for fixing the insulating cap 22. In this example, the insulating cap 22 is integrally formed and fixed on the protrusion 211C by injection molding process. If necessary, they can also be fixed by clamping or bonding, etc. A generally vertical partition wall is provided between the top surface 211B and the annular inclined shoulder 211A to separate them. The insulating cap 22 is in a truncated conical structure, with a maximum diameter of about 4.5 mm, which can be adjusted to 3 mm to 10 mm as needed, and the size of the front end face 124 where it is located should be adjusted accordingly. The maximum height of the insulating cap 22 is about 2 mm, which can be adjusted to 1 mm to 3 mm as needed. In this example, the maximum height-to-width ratio is 0.44, which can be further adjusted to 0.4 to 0.5 as needed. However, when the height-to-width ratio is maintained at 0.45 or below 0.3, the surface area and volume are smaller, the carbon particles released during high-temperature carbonization are less, and the overall efficiency loss caused by carbon pollution on the terminal surface is further reduced. It should be noted that the top of the insulating cap 22 is not limited to a flat surface. See Figure 5 If necessary, an opening 22A (indicated by a dashed line) can be formed to expose part of the front end face 124.

[0049] See Figure 5 The body portion 212 of the metal terminal 21 is a uniform cylindrical body, in this example, the maximum cylindrical diameter of the body portion 212 is about 5 mm, which can be adjusted to 4 mm to 10 mm as needed.

[0050] See Figure 5, the waist 213 is substantially cylindrical, comprising a front protruding ring 213A, a middle protruding ring 213B and a rear protruding ring 213C connected in sequence from front to rear. The front protruding ring 213A and the middle protruding ring 213B form a receiving groove 213D therebetween, and the maximum length of the receiving groove 213D in the front-rear direction is referred to as the receiving groove length L9. The receiving groove length L9 is the same as the maximum length of the stop ring 23 in the length direction D (front-rear direction), and is used for embedding the C-shaped stop ring 23. The stop ring 23 is designed to gradually thicken from thin front to thick rear, that is, the rear end 23B of the stop ring 23 is thicker than the front end 23A.

[0051] In this example, to prevent the metal terminal 21 from rotating in the axial direction, a rough surface 213E can be formed on the surface of the middle protruding ring 213B to increase the friction when contacting the pipe wall 111A of the rear pipe 111 of the main body 11 of the base 10. In this example, the rough surface 213E is a plurality of triangular protrusions extending uniformly from front to rear and interfering with the pipe wall 111A of the rear pipe 111 of the main body 11 to some extent. When the end of the metal terminal 21 is a wire, and the foot 214 does not need to be bent, the rough surface 213E design can be selectively omitted. The diameter of the rear protruding ring 213C is greater than that of the front protruding ring 213A and the rear protruding ring 213C, which is used to abut against the rear wall 114 of the main body 11 to limit the depth of the metal terminal 21 into the base 10.

[0052] See Figure 6 The foot 214 is a bent uniform cylindrical body, and the maximum diameter of the cylinder is referred to as the foot diameter L10, which is about 4 mm. If necessary, the foot diameter L10 is not less than 2 mm, and can be increased to 5 mm to 10 mm as needed, and is maximum the same width as the body 212. It should be noted that common high-current connectors can be full solder plate type, full solder wire type or hybrid type. Figure 1 The illustrated is a full solder plate type, each terminal is connected to the conductive through hole of the circuit board downward, or is a solder wire type, that is, the terminal foot 214 is not bent and straightened, and then the wire is welded to the tail thereof, and the hybrid type means that only one (such as the central ground terminal) is soldered, and the rest is welded to the circuit board, which is an example.

[0053] The above description is only an exemplary embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation made by using the content of the present application specification and drawings, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A high current connector for powering a server, characterized by, The large current connector comprises: a base formed integrally from an insulating material, the base comprising: a main body portion having a maximum height in a height direction of between 12mm and 26mm, the main body portion comprising a rear duct, the main body portion having two sides each provided with a through hole extending in a front-rear direction; and a socket portion having a maximum height in the height direction of between 11mm and 25mm, the maximum height of the socket portion being less than the maximum height of the main body portion, the socket portion being connected to the front of the main body portion, the socket portion comprising at least five front ducts arranged side by side, each of the front ducts being in communication with a corresponding rear duct and extending from the rear to the front, the socket portion having two sides each provided with a barb, the front end face of the wall between each two adjacent front ducts being provided with a transverse groove extending in a width direction and communicating the two front ducts, each of the front ducts comprising a positioning wall on an upper side, the positioning wall being provided with a positioning groove extending in the front-rear direction, the maximum depth of the positioning groove in the height direction being between 0.5mm and 1.4mm; a plurality of terminal modules, each of the terminal modules being embedded in the front duct and the corresponding rear duct, each of the terminal modules comprising a metal terminal, an insulating cap fixed to the top end of the metal terminal, and a C-shaped retaining ring buckled on the surface of the metal terminal, the retaining ring being used to abut against the base to prevent each corresponding metal terminal from being withdrawn rearwardly from the base, the metal terminal having a foot portion, the foot portion being cylindrical and having a diameter of between 2mm and 10mm; and two internally threaded metal pipes, each of the internally threaded metal pipes being embedded in the through hole on the two sides of the base to provide an internal thread in the through hole.

2. The high current connector of claim 1, wherein, The edges of the front end faces of the at least five front ducts arranged side by side are each provided with a guide slope, the thickness of the guide slope being between 0.05mm and 0.5mm.

3. The high current connector of claim 2, wherein, The insulating cap on the top end of the metal terminal comprises at least one opening.

4. The high current connector of claim 2, wherein, The rear end of the retaining ring is thicker than the front end.

5. The high current connector of claim 2, wherein, At least one of the at least five front ducts arranged side by side has a plurality of mutually adjacent walls inside, the plurality of walls comprising at least two shallow groove walls, the two shallow groove walls facing each other and each comprising a shallow groove extending in the front-rear direction.

6. The high current connector of claim 5, wherein, The two shallow groove walls are connected by at least two planar walls and the positioning wall, the depth of the shallow groove in the height direction being between 0.05mm and 0.5mm, and the shallow groove accounting for not more than 15% of the maximum thickness of the wall in which the shallow groove is located.

7. The high current connector of claim 6, wherein, The bottoms of the shallow grooves in the two shallow groove walls are each curved.

8. The high current connector of claim 2, wherein, The socket portion comprises an upwardly disposed upper common plane formed at least by the walls of the at least five front ducts arranged side by side and horizontal support walls connecting between the walls, and the socket portion comprises a downwardly disposed lower common plane formed at least by the walls of the at least five front ducts arranged side by side and the horizontal support walls connecting between the walls.

9. The high current connector of claim 8, wherein, Each of the front pipes has a front end opening in a polygonal shape without a circular line.

10. A high current connector for powering a server, characterized by, The large current connector comprises: a base formed integrally from an insulating material, the base comprising: a main body portion comprising a rear pipe, both sides of the main body portion each having a through hole extending in a front-rear direction; and a socket portion having a maximum height in a height direction smaller than that of the main body portion, the socket portion being connected to the front of the main body portion, the socket portion comprising at least five front pipes arranged side by side, each of the front pipes having a front end opening in a polygonal shape without a circular line, each of the front pipes being in communication with the corresponding rear pipe and extending from the rear to the front, both sides of the socket portion each having a barb, the front end surface of the pipe wall between every two adjacent front pipes each having a transverse groove extending in a width direction and in communication with the two front pipes, each of the front pipes comprising a positioning pipe wall on an upper side, the positioning pipe wall having a positioning groove extending in the front-rear direction; a plurality of terminal modules, each of the terminal modules being embedded in the front pipe and the corresponding rear pipe, each of the terminal modules comprising a metal terminal, an insulating cap fixed to the top end of the metal terminal, and a C-shaped retention ring buckled to the surface of the metal terminal, the retention ring being used to abut against the base to prevent each corresponding metal terminal from being withdrawn from the base in the rear direction, the metal terminal having a foot portion in a cylindrical shape; and two internally threaded metal pipes, each of the internally threaded metal pipes being embedded in the through hole on both sides of the base to provide an internal thread in the through hole.

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