Charging Connector for Electric Vehicles

Abstract

The present invention relates to a charging connector for an electric vehicle. Specifically, a hollow cylindrical first conductive terminal is provided within a connector base. An insulating spacer is disposed within the first conductive terminal, and a second conductive terminal is provided at the center of the spacer, such that the second conductive terminal is coaxially and electrically isolated within the first conductive terminal. Wherein, one or more annular grooves recessed from the surface are formed on the spacer, and the annular grooves coaxially surround the second conductive terminal, thereby lengthening the creepage distance between the positive terminal and the negative terminal and increasing the heat dissipation area to meet safety requirements.

Description

Technical Field

[0001] The present invention relates to a charging connector, and more particularly to an electric vehicle charging connector with a special design to increase the creepage distance and clearance. Background Art

[0002] According to the Chinese national standard GB 24155-2020 "Safety Requirements for Electric Motorcycles and Electric Mopeds", specific specifications are made for the creepage distance and clearance of the charging interface. Among them, the creepage distance of the power battery should meet the following requirements:

[0003] 1. The creepage distance d1 between the connection terminals of the power battery is calculated according to the following formula (1), with the unit of mm:

[0004] d1≥0.25U + 5 (1)

[0005] 2. The creepage distance d2 between the live part and the electric platform is calculated according to the following formula (2), with the unit of mm:

[0006] d2≥0.125U + 5 (2)

[0007] In the foregoing formulas (1) and (2), U is the maximum operating voltage between the two output terminals of the power battery, with the unit of volts.

[0008] In addition, the clearance between conductive parts should be not less than 2.5 mm.

[0009] Cooperation Figure 8 As shown, the measurement methods of the clearance and creepage distance can be known. It discloses two connection terminals 71 and 72 on a carrier 70. The two connection terminals 71 and 72 respectively have a conductive surface 710 and 720. The distance between the two conductive surfaces 710 and 720 is the clearance G, and the distance along the surface of the carrier 70 between the two connection terminals 71 and 72 is the creepage distance D.

[0010] From the above, it can be seen that China has the above requirements for the creepage distance and clearance of the charging interface for electric vehicles. Please refer to Figure 9 、 Figure 10, which discloses an existing connector for electric vehicles. There is a negative terminal 81 in a connector base 80. A positive terminal 82 is coaxially and electrically isolatedly arranged in the negative terminal 81. The negative terminal 81 is in a hollow cylindrical shape and has a communicating upper chamber 811 and a lower chamber 812 inside. The inner diameter of the upper chamber 811 is always larger than that of the lower chamber 812. A crown spring 813 is arranged in the upper chamber 811. The crown spring 813 is electrically connected to the negative terminal 81, and the crown spring 813 has a plurality of contact spring pieces. Each contact spring piece extends in an axial direction to form a contact point. When the above connector is engaged with a corresponding connector, the crown spring 813 is the main conduction medium for the negative power supply, and its contact points serve as the conductive surfaces of the negative terminal 81.

[0011] To achieve the coaxial and electrically isolated arrangement of the positive terminal 82 inside the negative terminal 81, an insulating seat 83 is arranged in the lower chamber 812 in a shape-matching manner, and the positive terminal 82 is arranged in the center of the insulating seat 83. Through the arrangement of the insulating seat 83, the positive terminal 82 and the negative terminal 81 are electrically isolated from each other. According to the requirements of the above Chinese national standard, the working voltage of this type of connector is 50.4 volts. Calculated according to the foregoing formula (1), its creepage distance must be greater than or equal to 17.6 mm (0.25 x 50.4 + 5), and the clearance must be greater than 2.5 mm. Corresponding to the above connector, it means that the creepage distance of the negative terminal 81 from the surface of the insulating seat 83 to the positive terminal 82 must be greater than 17.6 mm. The contact points of the crown spring 813 serve as the conductive surfaces of the negative terminal 81, and the clearance between it and the positive terminal 82 must be greater than 2.5 mm. However, as Figure 11 shown, according to the actual measurement results, the clearance G1 from the contact point of the crown spring 813 of the negative terminal 81 to the positive terminal 82 is 5.375 mm, which is always greater than the standard 2.5 mm and meets the safety requirements. However, the creepage distance D1 of the negative terminal 81 from the surface of the insulating seat 83 to the positive terminal 82 is only 3.8 mm, far lower than the safety requirement of 17.6 mm and does not meet the regulations.

[0012] In terms of external connection of the above connector, there is also a problem that the creepage distance does not meet the safety requirements. Please refer to Figure 12 、 Figure 13As shown, the negative terminal 81 and the positive terminal 82 are respectively connected to an electrical connection piece 84 and 85. One end of the two electrical connection pieces 84 and 85 is respectively fixed to the bottom of the negative terminal 81 and the positive terminal 82, and the other end is bent and extended beyond the bottom of the connector base 80 for external electrical connection. Based on the specifications of the connector, the two electrical connection pieces 84 and 85 are arranged at two adjacent positions at the bottom of the connector base 80. The shortest distance D2 between them is 6.20 mm, which meets the requirement that the creepage distance must be greater than or equal to 2.5 mm, but the creepage distance is much lower than the requirement of at least 17.6 mm.

[0013] As can be seen from the above, the existing electric vehicle connectors cannot meet the safety requirements in terms of creepage distance, so it is necessary to further review and seek feasible solutions. Summary of the Invention

[0014] Therefore, the main object of the present invention is to provide a charging connector for electric vehicles, which meets the safety requirements by special terminal and insulation structures to expand the creepage distance and electrical clearance.

[0015] The main technical means adopted to achieve the foregoing object is to make the aforementioned charging connector for electric vehicles include:

[0016] A connector base;

[0017] A first conductive terminal, one end of which is arranged inside the connector base and the other end is exposed outside the connector base; the first conductive terminal is in the shape of a hollow cylinder and has an upper groove chamber and a lower groove chamber inside. The lower groove chamber is further formed with a constricted groove wall to expand the inner diameter of the lower groove chamber;

[0018] An isolator, which is arranged in the lower groove chamber of the first conductive terminal in a shape-matching manner; one or more downwardly recessed annular grooves are coaxially formed on the surface of the isolator;

[0019] A second conductive terminal, which is arranged at the center of the isolator and is coaxially and electrically isolated inside the first conductive terminal. One end of the second conductive terminal is located in the upper groove chamber of the first conductive terminal, and the other end extends out of the bottom of the isolator.

[0020] The first conductive terminal of the aforementioned connector forms a constricted groove wall in its lower groove chamber to expand the inner diameter of the lower groove chamber and relatively increase the outer diameter of the isolator arranged therebetween, thereby extending the creepage distance from the first conductive terminal along the surface of the isolator to the second conductive terminal; furthermore, since the isolator is formed with annular grooves recessed from the surface, the creepage distance from the first conductive terminal along the surface of the isolator to the second conductive terminal will be further extended, and on the other hand, the heat dissipation area of the isolator surface can be expanded, fully meeting the safety requirements. Description of the Drawings

[0021] Figure 1 Isometric view of a preferred embodiment of the present invention;

[0022] Figure 2 Cross-sectional view of a preferred embodiment of the present invention;

[0023] Figure 3 Partial cross-sectional view of a preferred embodiment of the present invention;

[0024] Figure 4 Local cross-sectional view of a preferred embodiment of the present invention;

[0025] Figure 5 Exploded view of the elastic contact member and the contact spring of a preferred embodiment of the present invention;

[0026] Figure 6 Bottom isometric view of a preferred embodiment of the present invention;

[0027] Figure 7 Bottom plan view of a preferred embodiment of the present invention;

[0028] Figure 8 Schematic diagram for calculating creepage distance;

[0029] Figure 9 Isometric view of an existing electric vehicle connector;

[0030] Figure 10 Combined cross-sectional view of an existing electric vehicle connector;

[0031] Figure 11 Local cross-sectional view of an existing electric vehicle connector;

[0032] Figure 12 Bottom isometric view of an existing electric vehicle connector;

[0033] Figure 13 Bottom plan view of an existing electric vehicle connector. Detailed implementation manners

[0034] Regarding a preferred embodiment of the present invention, first please refer to Figure 1 、 Figure 2As shown, a first conductive terminal 20 is mainly provided inside a connector base 10, and a second conductive terminal 30 is coaxially and electrically isolated inside the first conductive terminal 20; the first conductive terminal 20 can be a negative conductive terminal or a positive conductive terminal, and the second conductive terminal 30 can correspondingly be a positive conductive terminal or a negative conductive terminal. In the following embodiments, the first conductive terminal 20 serves as the negative conductive terminal and the second conductive terminal 30 serves as the positive conductive terminal. However, it must be noted that the above-mentioned first conductive terminal 20 and second conductive terminal 30 serving as the negative conductive terminal and positive conductive terminal respectively are only examples and are not used to limit their functions.

[0035] The connector base 10 is hollow, and a protruding and annular high platform 11 is formed at its upper end. The first conductive terminal 20 is disposed inside the high platform 11 in a shape-matching manner.

[0036] The first conductive terminal 20 is in the shape of a hollow cylinder. One end is located inside the high platform 11 of the connector base 10, and the other end extends out of the high platform 11. An upper groove chamber 21 and a lower groove chamber 22 that communicate with each other are formed inside the first conductive terminal 20. The inner diameter of the upper groove chamber 21 is larger than that of the lower groove chamber 22. The lower groove chamber 22 further forms a constricted groove wall 220, mainly to relatively expand the inner diameter of the lower groove chamber 22 by constricting the groove wall.

[0037] An isolating member 40 is disposed inside the lower groove chamber 22 of the first conductive terminal 20 in a shape-matching manner. The isolating member 40 is made of an insulating material and has a surface that is exposed at the bottom of the upper groove chamber 21. One or more downwardly recessed annular grooves are coaxially formed on the surface of the isolating member 40. Please refer to Figure 3 As shown, in this embodiment, an outer annular groove 41 and an inner annular groove 42 are respectively formed on the surface of the isolating member 40. The outer annular groove 41 is located on the periphery of the inner annular groove 42, has a larger outer diameter and a larger depth. The depth of the outer annular groove 41 is greater than half of the height of the isolating member 40. Compared with the outer annular groove 41, the inner annular groove 42 is closer to the center of the isolating member 40. The depth of the inner annular groove 42 is always less than the depth of the outer annular groove 41, and a step 420 is formed on the side wall close to the center.

[0038] The second conductive terminal 30 is disposed at the center of the isolating member 40 and is surrounded by the outer annular groove 41 and the inner annular groove 42 on the surface of the isolating member 40. One end of the second conductive terminal 30 is exposed between the upper groove chambers 21 of the first conductive terminal 20, and the other end extends out of the bottom of the isolating member 40. Please refer to Figure 3As shown, since the lower chamber 22 of the first conductive terminal 20 forms a retracted groove wall 220 to expand the inner diameter, the outer diameter of the relatively enlarged spacer 40 is increased, thereby extending the creepage distance between the first conductive terminal 20 and the second conductive terminal 30 in the horizontal direction. On the other hand, the surface of the spacer 40 forms a downwardly recessed outer ring groove 41 and an inner ring groove 42, which further lengthens the creepage distance in the vertical direction. For reference, Figure 4 As shown, the specific creepage distance between the first conductive terminal 20 and the second conductive terminal 30 is the distance of multiple height differences on the surface of the spacer 40 The total sum is obtained. After specific actual measurement, the creepage distance can reach 18.23 mm, meeting the safety requirement of being greater than 17.6 mm.

[0039] On the other hand, since the spacer 40 forms an outer ring groove 41 and an inner ring groove 42 on its surface, it greatly expands the surface area of the spacer 40, so that the surface of the spacer 40 has a large heat dissipation area.

[0040] Regarding the electrical clearance, please refer to Figure 3 As shown, a crown spring 23 is electrically connected in the upper chamber 21 of the first conductive terminal 20. The crown spring 23 has a plurality of contact spring pieces, and each contact spring piece extends in an axial direction of the first conductive terminal 20 to form a contact point 230. The electrical clearance between the first conductive terminal 20 and the second conductive terminal 30 is the distance from the contact point 230 of the crown spring 23 to the second conductive terminal 30, which is always greater than 2.5 mm specified by the safety requirement standard.

[0041] The following further describes the specific structure of the second conductive terminal 30. Please refer to Figure 3 As shown, the second conductive terminal 30 is a long and narrow hollow tube, and a upper channel 31 and a lower channel 32 that are connected and communicated are formed inside it. The aperture of the upper channel 31 is larger than that of the lower channel 32, and the lower channel 32 is a threaded hole. An elastic contact member 33 and a contact spring 34 are provided in the upper channel 31 of the second conductive terminal 30. The contact spring 34 is located at the lower end of the upper channel 31, and the elastic contact member 33 is in the form of a crown spring and is located at the upper end of the upper channel 31 and above the contact spring 34.

[0042] Please refer to Figure 5As shown, the elastic contact member 33 includes an upper ring 331, a lower ring 332, and a plurality of contact spring pieces 333 with two ends respectively connected to the upper ring 331 and the lower ring 332. Each contact spring piece 333 extends in an axial direction of the upper ring 331 and the lower ring 332 to respectively form a contact point. In this embodiment, the distance between the contact point of each contact spring piece 333 and the lower ring 332 is greater than the distance between the contact point and the upper ring 331. Compared with the traditional crown spring, the elastic contact member 33 lengthens the length (lever arm) of the contact spring piece 333, and can extend the service life of the elastic contact member 33.

[0043] The upper end of the contact spring 34 has a converging portion 341. The outer diameter of the converging portion 341 is smaller than the inner diameter of the lower ring 332 of the elastic contact member 33 and larger than the inner diameter of the elastic contact member 33 at its contact point, so that the converging portion 341 is located below the contact point of the elastic contact member 33. The lower end of the contact spring 34 has a closely wound portion 342 with densely wound turns. Please refer to Figure 3 As shown, a stud 35 is inserted through the lower end of the closely wound portion 342 of the contact spring 34. The stud 35 is screwed into the lower hole 32 of the second conductive terminal 30, thereby fixing the contact spring 34 in the upper hole 31 of the second conductive terminal 30.

[0044] Please refer to Figure 1 、 Figure 6 As shown, on one side of the bottom of the connector base 10, a first electrical contact piece 200 and a second electrical contact piece 300 are simultaneously provided. The first electrical contact piece 200 and the second electrical contact piece 300 are opposite to each other at an angle. One ends of them are respectively electrically connected to the bottoms of the first conductive terminal 20 and the second conductive terminal 30 inside the connector base 10. The first electrical contact piece 200 and the second electrical contact piece 300 extend out of the bottom of the connector base 10 in the vertical direction, and then twist and extend in the horizontal direction, so that the other ends of the first electrical contact piece 200 and the second electrical contact piece 300 are arranged in parallel (please refer to Figure 7 As shown). The parts of the first electrical contact piece 200 and the second electrical contact piece 300 exposed outside the connector base 10 are respectively covered with an insulating layer 201 and 301 except for the bare ends for power supply connection. By means of the arrangement of the insulating layers 201 and 301, the creepage distance of the first electrical contact piece 200 and the second electrical contact piece 300 can be greatly extended, and the specifications of safety requirements can be fully met.

[0045] According to the description of the foregoing specific embodiments, the inner diameter of the lower slot of the first conductive terminal of the present invention is enlarged, thereby lengthening the outer diameter of the spacer, and the creepage distance between the first conductive terminal and the second conductive terminal is extended in the horizontal direction. Moreover, one or more recessed annular grooves are formed on the surface of the spacer, further enlarging the aforementioned creepage distance in the vertical direction, so as to have a sufficient distance to meet the requirements of safety regulations. Furthermore, when annular grooves are formed on the surface of the spacer, its surface area is also significantly enlarged, which helps to increase the heat dissipation area of the spacer. On the other hand, insulating layers are provided on the portions of the first electrical connection piece and the second electrical connection piece for external connection that are exposed from the connector base, so that the creepage distance between the first electrical connection piece and the second electrical connection piece can also meet the safety requirements.

Claims

1. A charging connector for an electric vehicle, characterized in that, it includes: a connector base; a first conductive terminal, one end of which is arranged inside the connector base and the other end is exposed outside the connector base; the first conductive terminal is in the shape of a hollow cylinder, and has an upper slot chamber and a lower slot chamber inside it, and the lower slot chamber is further formed with a constricted slot wall to expand the inner diameter of the lower slot chamber; an isolation member, which is arranged in the lower slot chamber of the first conductive terminal in a shape-matching manner; one or more downwardly recessed annular grooves are coaxially formed on the surface of the isolation member; a second conductive terminal, which is arranged at the center of the isolation member to be coaxially and electrically isolated inside the first conductive terminal, one end of the second conductive terminal is located in the upper slot chamber of the first conductive terminal, and the other end extends out of the bottom of the isolation member; wherein, an outer annular groove and an inner annular groove are respectively formed on the surface of the isolation member, and the outer annular groove is located on the periphery of the inner annular groove; the depth of the inner annular groove is always less than the depth of the outer annular groove, and a step is formed on one side wall of the inner annular groove close to the center of the isolation member.

2. The charging connector for an electric vehicle according to claim 1, characterized in that, the depth of the outer annular groove is greater than half of the height of the isolation member.

3. The charging connector for an electric vehicle according to claim 1, characterized in that, the second conductive terminal is a long and narrow hollow tube, and a communicating upper hole channel and a lower hole channel are formed inside it, and the aperture of the upper hole channel is larger than the aperture of the lower hole channel; an elastic contact member and a contact spring are arranged in the upper hole channel of the second conductive terminal, the contact spring is located at the lower end of the upper hole channel, and the elastic contact member is located at the upper end of the upper hole channel and above the contact spring.

4. The charging connector for an electric vehicle according to claim 3, characterized in that, the elastic contact member is in the form of a crown spring, which includes an upper ring, a lower ring and a plurality of contact spring pieces respectively connecting the upper ring and the lower ring at both ends, and each contact spring piece extends towards an axial direction of the upper ring and the lower ring to respectively form a contact point, and the distance between the contact point of each contact spring piece and the lower ring is greater than the distance between the contact point and the upper ring.

5. The charging connector for an electric vehicle according to claim 3, characterized in that, the upper end of the contact spring has a constricted portion, the outer diameter of the constricted portion is smaller than the inner diameter of the lower ring of the elastic contact member and larger than the inner diameter of the elastic contact member at its contact point, and the constricted portion is located below the contact point of each contact spring piece of the elastic contact member.

6. The charging connector for an electric vehicle according to claim 5, characterized in that, the lower hole channel of the second conductive terminal is a threaded hole; the lower end of the contact spring has a densely wound portion with densely wound turns, and a stud is penetrated through the densely wound portion at the lower end of the contact spring, and the stud is screwed in the lower hole channel of the second conductive terminal.

7. The charging connector for an electric vehicle according to claim 1, characterized in that, One side of the bottom of the connector base is provided with a first electrical contact piece and a second electrical contact piece at the same time. The first electrical contact piece and the second electrical contact piece face each other at an angle. One end of each of them is electrically connected to the bottom of the first conductive terminal and the second conductive terminal respectively inside the connector base. The parts of the first electrical contact piece and the second electrical contact piece that are exposed outside the connector base are respectively covered with an insulating layer except for the bare ends for power supply connection.

8. The charging connector for electric vehicles according to claim 7, characterized in that, the first electrical contact piece and the second electrical contact piece extend out of the bottom of the connector base in the vertical direction, and then twist and extend in the horizontal direction, so that the other ends of the first electrical contact piece and the second electrical contact piece are arranged in parallel.

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