JP2018156771A - Female terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress contact resistance between a male terminal and a female terminal to a low level while suppressing the cutting cost of the female terminal.SOLUTION: Disclosed is a female terminal 10 which is fitted to a male terminal 30 having a male side body part 31 forming a rod shape. This terminal includes: a female side body part 11 forming a long shape in the longitudinal direction and also forming a solid columnar shape; eight elastic contact pieces 13, each of which is composed of a base material made of a copper alloy obtained by adding tellurium which is one of free cutting elements thereto, protrudes forward from the female side body part 11 and elastically comes into contact with the male side body part 31 of the male terminal 30; a silver plating layer formed on the surface on the side in contact with the male terminal 30 of the elastic contact piece 13; and a male side wire connection part 16 which protrudes backward from the female side body part 11.SELECTED DRAWING: Figure 1

Description

  The technique disclosed by this specification is related with a female terminal.

  Conventionally, as an example of a female terminal used in a charging connector such as an EV, a female terminal described in Japanese Patent Application Laid-Open No. 2011-228061 (the following Patent Document 1) is known. The female terminal has a shape that is long in the front-rear direction, and is a solid and cylindrical female main body, and a plurality (usually four to six) of contact pieces protruding forward from the female main body. The flange portion is provided around the outer peripheral surface of the female-side main body portion, and the barrel portion protrudes rearward from the female-side main body portion.

  In general, a copper alloy is used as a rod material as a base material of the female terminal. The female terminal is manufactured by cutting the rod material. Further, the cut female terminal is plated with silver or the like.

  On the other hand, the male terminal fitted to the female terminal has a long shape in the front-rear direction, a male-side main body portion that forms a rod shape, a flange portion that is provided around the outer peripheral surface of the male-side main body portion, and a male side And a barrel portion projecting rearward from the main body portion.

  When the male terminal and the female terminal are fitted, the main body portion that forms the rod shape of the male terminal is sandwiched between the plurality of contact pieces of the female terminal, and elastically contacts the main body portion of the male terminal. As a result, the male terminal and the female terminal are electrically connected. When energization is performed when the male terminal and the female terminal are fitted, contact resistance is generated at the terminal contact portion between the male terminal and the female terminal, and thus heat is generated at the terminal contact portion.

JP 2011-228061 A

  In recent years, a further increase in charging speed has been eagerly desired, and a larger current is required to flow through the terminals when energized. When such a large current flows through the female terminal having the above structure, a large amount of heat is generated at the terminal contact portion between the male terminal and the female terminal. In order to suppress such heat generation at the terminal contact portion, it is necessary to keep the contact resistance between the male terminal and the female terminal low. In order to keep the contact resistance between the male terminal and the female terminal low, it is conceivable to increase the number of terminal contact portions between the male terminal and the female terminal by increasing the number of contact pieces of the female terminal.

  However, when the number of contact pieces of the female terminal is increased, the shape of the female terminal becomes complicated, so that there is a problem that the cost of cutting the female terminal increases. In particular, the diameter of the female terminal of the charging connector is determined by the standard. When processing so that the number of contact pieces of the female terminal is more than six within the diameter range that conforms to the standard, Cutting was expensive.

The female terminal disclosed in this specification is a female terminal fitted to a male terminal having a male main body portion that has a rod shape, has a long shape in the front-rear direction, and is solid and cylindrical. Eight elastic contacts comprising a female-side main body and a copper alloy base material added with a free-cutting element, protruding forward from the female-side main body and elastically contacting the male-side main body of the male terminal A piece, a silver plating layer formed on the surface of the elastic contact piece on the side in contact with the male terminal, and a female electric wire connecting portion protruding rearward from the female main body.
With such a configuration, the elastic contact piece of the female terminal is processed as compared with the copper alloy to which the free cutting element is not added because the copper alloy with the free cutting element added is used as the base material for the elastic contact piece of the female terminal. Machinability at the time can be improved. Accordingly, eight elastic contact pieces can be provided on the female terminal while suppressing the cutting cost of the female terminal. Furthermore, since the number of contacts between the male terminal and the female terminal is eight, the contact resistance between the male terminal and the female terminal can be kept low.

Further, tellurium may be used as the free-cutting element.
With such a configuration, a certain amount of tellurium, which is one of the free-cutting elements, is added to copper, so that compared to a copper alloy that does not contain free-cutting elements, the coverage when processing the elastic contact piece of the female terminal is increased. The machinability can be improved.

The silver plating hardness of the silver plating layer may be 75 Vickers hardness or more and 85 Vickers hardness or less.
With such a configuration, the silver plating layer is softer than the silver plating layer at 120 Vickers hardness, which is the hardness of silver plating that is usually used, and therefore between the elastic contact piece and the male main body. The contact area becomes larger. Thereby, the contact resistance between an elastic contact piece and a male side main-body part can be restrained low. Further, when the contact area between the elastic contact piece and the male side main body portion is equal to the contact area between the elastic contact piece and the male side main body portion at 120 Vickers hardness, the elastic contact The contact load between the piece and the male main body is lower than when the silver plating hardness is 120 Vickers hardness. Therefore, it is possible to suppress the insertion force when the male main body is inserted into the elastic contact piece.

  According to the female terminal disclosed in the present specification, it is possible to reduce the contact resistance between the male terminal and the female terminal while suppressing the cutting cost of the female terminal.

Front perspective view of female terminal Rear perspective view of female terminal Front view of female terminal Left side view of female terminal Right side view of female terminal AA sectional view in FIG. BB sectional view in FIG. Perspective view when mating male and female terminals Front view when mating male and female terminals Left side view when mating male and female terminals CC sectional view in FIG. DD sectional view in FIG. The enlarged view of the contact of the male terminal and female terminal in FIG.

<Embodiment>
The embodiment will be described with reference to FIGS.

  The female terminal 10 of the present embodiment is used as a charging connector for charging a battery provided in a vehicle such as an electric vehicle or a hybrid vehicle. The female terminal 10 is made by cutting a tellurium copper alloy bar, and includes a female main body 11, eight elastic contact pieces 13, and a female electric wire connection 16. Further, the processed female terminal 10 is subjected to silver plating. Here, the tellurium copper alloy is a high copper alloy made by adding tellurium (Te), which is one of free-cutting elements, to the pure copper at a ratio of 0.3% to 2.0%. . A free-cutting element is an element that improves the machinability of a metal when added to the metal. As the free-cutting element, sulfur (S), lead (Pb), selenium (Se), phosphorus (P), nitrogen (N) and the like are known in addition to tellurium. Tellurium copper alloys have superior machinability compared to copper alloys that do not contain free-cutting elements. The machinability is a characteristic that is generally evaluated based on cutting resistance, tool life, cutting finish surface roughness, cutting scrap disposability, and the like. The conductivity of the tellurium copper alloy is equivalent to that of pure copper. In the following description, the fitting direction of the female terminal 10 with the male terminal 30 is the front.

  The female side main body 11 has a shape that is long in the front-rear direction, and is solid and columnar. Furthermore, an annular female flange 12 is provided around the rear end of the female main body 11. Although not shown, the female flange portion 12 plays a role of preventing the front terminal from coming off when the female terminal 10 is inserted into the female connector housing. Further, although not shown, it plays the role of preventing the backward disconnection so that the female terminal 10 inserted into the female connector housing does not fall backward. Although not shown in the figure, the rear omission can be prevented by pressing the female flange portion 12 from the rear by a retainer attached to the female connector housing.

  Eight elastic contact pieces 13 are arranged at equal intervals in the circumferential direction of the female main body 11 and are provided to protrude forward. The elastic contact piece 13 includes a contact piece base end portion 14 and a contact piece tip end portion 15. A small slit 17 is inserted between adjacent contact piece tip portions 15. A large slit 18 is provided between adjacent contact piece base ends 14. The large slit 18 plays a role of discharging muddy water to the outside when muddy water or the like enters the inside of the elastic contact piece 13. The inner surface of the contact piece tip 15 is tapered so that the inner diameter increases toward the outer side in the radial direction toward the front. As a result, the contact piece tip 15 serves as a guide when a male-side main body 31 of the male terminal 30 to be described later is inserted into the elastic contact piece 13 of the female terminal 10.

  The silver plating base surface 19 of the elastic contact piece 13 is subjected to silver plating. Thus, a silver plating layer 20 is formed on the silver plating base surface 19. The hardness of the silver plating layer 20 is 75 Vickers hardness or more and 85 Vickers hardness or less.

  The female-side electric wire connection portion 16 has a closed barrel shape, and the rear side is opened in a cylindrical shape. The outer diameter of the female-side wire connecting portion 16 is processed to be smaller than the outer diameter of the female-side flange portion 12. A core wire of an electric wire (not shown) is connected to the female-side electric wire connecting portion 16 by crimping. Thereby, the female terminal 10 and the electric wire are electrically connected.

  The male terminal 30 is made by cutting a copper alloy bar, and includes a male main body portion 31 and a male electric wire connecting portion 33.

  The male side main body 31 has a rod shape. The outer diameter of the male main body portion 31 is processed to be larger than the minimum inner diameter R1 of the eight contact piece tip portions 15 of the female terminal 10. Thereby, when the male terminal 30 and the female terminal 10 are fitted, the male side main body part 31 and the eight contact piece tip parts 15 of the female terminal 10 are elastically contacted. An annular male flange portion 32 is provided around the rear end portion of the male main body portion 31. Although not shown, the male flange portion 32 plays a role of preventing the male terminal 30 from falling forward when the male terminal 30 is inserted into the male connector housing. Further, although not shown, it plays the role of preventing the rear terminal from being pulled out so that the male terminal 30 inserted into the male connector housing does not fall backward.

  The male electric wire connecting portion 33 has a closed barrel shape, and the rear side is opened in a cylindrical shape. The outer diameter of the male-side electric wire connecting portion 33 is processed to be smaller than the outer diameter of the male-side flange portion 32. An unillustrated core wire of an electric wire (not shown) is connected to the male electric wire connecting portion 33 by crimping. Thereby, the male terminal 30 and the electric wire are electrically connected.

  Next, the operation of this embodiment will be described.

  A tellurium copper alloy bar is cut to provide the female main body 11 and the female flange 12. Next, the rear part of the bar is punched into a cylindrical shape to provide the female-side wire connection part 16. Next, in order to provide eight elastic contact pieces 13, first, the front portion of the bar is cut into a cylindrical shape. Subsequently, the inner surface of the tip of the bar is processed into a taper shape so that the inner diameter increases toward the outer side in the radial direction toward the front. Subsequently, eight large slits 18 are formed at equal intervals in the circumferential direction to form the contact piece base end portion 14. Subsequently, eight small slits 17 are formed at the tip of the bar at the same interval as the large slit 18 to form the contact piece tip 15. Thereby, the eight elastic contact pieces 13 are formed. Subsequently, a drill having the same diameter as the outer diameter of the male main body 31 is placed inside the elastic contact piece 13 to elastically contact the elastic contact piece 13 and the drill. Thereby, the inner surface of the elastic contact piece 13 is processed, and the silver plating base surface 19 is formed. When the male side main body 31 is inserted into the elastic contact piece 13, the male side main body 31 and the silver plating base surface 19 come into surface contact. Subsequently, the silver plating base surface 19 is subjected to silver plating. The female terminal 10 is made as described above. Since the female terminal 10 uses a copper alloy bar material to which tellurium, one of free-cutting elements, is added as a base material, it is compared with a case where a copper alloy bar material to which no free-cutting element is added is used. Thus, the cutting time can be shortened. Generally, as the number of contact pieces increases, the processing time of the bar increases. However, by using a tellurium copper alloy bar as the base material of the female terminal 10, the conventional six contact pieces are cut. The eight elastic contact pieces 13 can be cut in a time equivalent to the time required for.

  The silver plating base surface 19 of the elastic contact piece 13 of the female terminal 10 is subjected to a silver plating process having a hardness of 75 Vickers hardness or more and 85 Vickers hardness or less. Thereby, the silver plating layer 20 is formed on the silver plating base surface 19. Then, the male side main body 31 of the male terminal 30 is inserted into the internal space of the eight elastic contact pieces 13 of the female terminal 10. The male side main body 31 is elastically pressed by the elastic contact piece 13 of the female terminal 10. At this time, the silver plating layer 20 is crushed by the elastic contact piece 13 by being sandwiched between the silver plating base surface 19 of the elastic contact piece 13 and the male main body 31. Thereby, the silver plating layer 20 and the male side main-body part 31 contact in contact area S1. On the other hand, when the conventional silver plating layer 20a having a silver plating hardness of 120 Vickers is provided on the silver plating base surface 19a of the elastic contact piece 13a, the hardness of the silver plating is 75 Vickers or more and 85 Vickers The silver plating layer 20a is less likely to be crushed by the elastic contact piece 13a than the silver plating layer 20 having a hardness or less. Therefore, the contact area S1a between the conventional silver plating layer 20a and the male main body 31 is smaller than the contact area S1 between the silver plating layer 20 and the male main body 31. Therefore, the contact area between the elastic contact piece 13 and the male main body 31 can be increased by using silver plating having a hardness of 75 Vickers hardness or more and 85 Vickers hardness or less. Further, when the contact area S1 is the same as the contact area S1a when the conventional silver plating layer 20a is used, the contact load of the elastic contact piece 13a when the conventional silver plating layer 20a is used. A contact area equivalent to the conventional contact area S1a can be obtained with a small contact load. Thereby, the insertion force to the elastic contact piece 13 of the female terminal 10 of the male side main-body part 31 can be suppressed.

  As described above, according to this embodiment, since the copper alloy to which tellurium, which is one of the free-cutting elements, is used as the base material for the elastic contact piece 13 of the female terminal 10, it is compared with a copper alloy to which no tellurium is added. The machinability at the time of processing the elastic contact piece 13 of the female terminal 10 can be improved. Accordingly, the eight elastic contact pieces 13 can be provided on the female terminal 10 while suppressing the cutting cost of the female terminal 10. Furthermore, since the number of contacts between the male terminal 10 and the female terminal 30 is eight, the contact resistance between the male terminal 30 and the female terminal 10 can be kept low.

  Moreover, since the silver plating layer 20 becomes soft compared with the silver plating layer 20a at the time of 120 Vickers hardness which is the hardness of silver plating normally used, between the elastic contact piece 13 and the male side main-body part 31. The contact area S1 increases. Thereby, the contact resistance between the elastic contact piece 13 and the male side main-body part 31 can be restrained low. Further, the contact area S1 between the elastic contact piece 13 and the male main body 31 is equal to the contact area S1a between the elastic contact piece 13a and the male main body 31 when the silver plating hardness is 120 Vickers hardness. When the contact area is equal to the contact area, the contact load between the elastic contact piece 13 and the male main body 31 is lower than when the silver plating hardness is 120 Vickers hardness. Therefore, it is possible to suppress the insertion force when inserting the male side main body 31 into the elastic contact piece 13.

<Other embodiments>
The technology disclosed in the present specification is not limited to the embodiments described with reference to the above description and drawings, and includes, for example, the following various aspects.
(1) In the above embodiment, tellurium is added as a free-cutting element. However, free-cutting elements other than tellurium may be added. For example, any one of sulfur, lead, selenium, phosphorus, and nitrogen may be added, or a plurality of free-cutting elements may be added in combination.
(2) In the above embodiment, tellurium is added to pure copper, but it may be added to a copper alloy. For example, it is good also as adding with respect to copper alloys, such as brass and bronze.
(3) In the above embodiment, tellurium is added to pure copper at a ratio of 0.3% or more and 2.0% or less, but any addition ratio may be used.
(4) In the above embodiment, the hardness of silver plating is 75 Vickers hardness or more and 85 Vickers hardness or less, but other hardness may be used.

DESCRIPTION OF SYMBOLS 10 ... Female terminal 11 ... Female side main-body part 12 ... Female side flange part 13, 13a ... Elastic contact piece 14 ... Contact piece base end part 15 ... Contact piece tip part 16 ... Female side electric wire connection part 17 ... Small slit 18 ... Large Slits 19, 19a ... Silver plated base 20, 20a ... Silver plated layer 30 ... Male terminal 31 ... Male side body part 32 ... Male side flange part 33 ... Male side wire connection part R1 ... Minimum inner diameter of the tip of the elastic contact piece S1, S1a ... contact area

Claims (3)

It is a female terminal fitted with a male terminal having a male-side main body that forms a rod shape,
It has a long shape in the front-rear direction, a solid and cylindrical female main body,
It consists of a base material made of a copper alloy to which a free-cutting element is added, protrudes forward from the female-side main body, and eight elastic contact pieces that elastically contact the male-side main body of the male terminal;
A silver plating layer formed on the surface of the elastic contact piece in contact with the male terminal;
A female terminal comprising a female electric wire connecting portion protruding rearward from the female main body.   The female terminal according to claim 1, wherein tellurium is used as the free-cutting element.   3. The female terminal according to claim 1, wherein a silver plating hardness of the silver plating layer is 75 Vickers hardness or more and 85 Vickers hardness or less.

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