Anti-wear terminal fitting

Abstract

A female receptacle terminal (10) for an electrical connector is disclosed. The female receptacle terminal comprises a receptacle having an opening (20) for receiving a male blade terminal (300) in an insertion direction (M). An elastic contact beam (100) extends from an upper portion of the receptacle toward an opposing lower portion. At least one contact surface (103, 113) is provided on at least one of the elastic contact beam and the lower portion, and has a contact bump (105, 115) curved in the insertion direction and width direction to engage with the male blade terminal at a line contact interface, and a guide portion (101, 111) parallel to the lower portion and linear in the width direction in a plane perpendicular to the width direction to engage with the male blade terminal at a point contact interface. Additionally, a male blade terminal, an electrical connector, and a method for forming an electrical connection are disclosed.

Description

Technology Field

[0001] The present invention relates to the field of terminal fittings, and in particular to terminal fittings used in electrical connectors. Background Technology

[0002] Currently, electrical connectors typically transmit power and signals through a contact interface comprising a female receptacle terminal and a male blade terminal. The terminals are made of conductive materials, such as copper-based alloys. The materials have a plating layer deposited on at least the contact portions of the terminal system. Plating materials include, but are not limited to, gold, silver, tin, and nickel. In these terminal systems, during mating and non-mating, the plating materials tend to wear out or plow. This degradation increases insertion force and electrical resistance.

[0003] There is a need for an improved terminal system with increased wear resistance.

[0004] An important factor to control in the design of electrical terminals is the force required to mate the female receptacle terminal with the male blade terminal. This is particularly important in connector arrays comprising multiple female receptacle terminals configured to mate simultaneously with a corresponding number of male blade terminals, because the total insertion force will be a multiple of the single insertion force required for a single set of female and male terminals. Another important factor is the repeatability of the insertion force over multiple mates and non-mates, that is, over multiple connect and disconnect cycles. In known electrical connectors, the inventors have identified that a significant amount of wear occurs when the male blade terminal is inserted into the female receptacle terminal. As this wear worsens with the use of the electrical connectors, the insertion force may become larger or less predictable over time. The inventors have devised a solution to this problem as outlined below.

[0005] According to one embodiment, a female receptacle terminal for an electrical connector is provided, wherein the female receptacle terminal comprises any or all of the following features: a receptacle—the receptacle has an opening configured to receive a male blade terminal into the receptacle in an insertion direction along the insertion axis—; an elastic contact beam extending from an upper portion of the receptacle toward an opposing lower portion of the receptacle; and at least one contact surface configured to engage with the male blade terminal during insertion of the male blade terminal into the receptacle, wherein the at least one contact surface is provided on at least one of the elastic contact beam and the lower portion and has an external shape that protrudes laterally into the receptacle and is curved in both the insertion direction and the width direction of the receptacle; and includes a guide portion having an external shape that protrudes laterally into the receptacle, is linear in the width direction in a plane perpendicular to the insertion direction, and is parallel to the bottom portion, the guide portion is positioned adjacent to the contact bump and closer to the opening than the contact bump, so that during insertion of the male blade terminal into the receptacle, the guide portion engages with the male blade terminal before the contact bump.

[0006] By providing a contact surface having the above arrangement, the male blade terminal inserted into the receptacle will move toward its fully inserted position and first meet the guide portion before meeting the contact bump. By arranging the guide portion to have an external shape that is linear in the width direction in a plane perpendicular to the insertion direction and parallel to the bottom portion, the guide portion can provide line contact at the interface between the contact surface and the male blade terminal. This distributes force over a significant proportion of the width of the male blade terminal. By arranging the contact bump to have an external shape that is curved in both the insertion direction and the width direction of the receptacle, a point contact interface is provided between the contact surface and the male blade terminal. In this way, as the male blade terminal is inserted into the receptacle, the male blade terminal will engage with the guide portion along the line contact interface before engaging with the contact bump at the point contact interface. The inventors have confirmed that this provides a favorable pressure distribution across the male blade terminal, reduces significant wear formations during mating, and still provides a good electrical connection through the contact bump once the male blade terminal is fully inserted. Overall, this arrangement reduces insertion force and reduces or eliminates wear on terminal contact surfaces, thereby providing electrical connectors that are easier to assemble and more robust.

[0007] At least one contact surface may include an upper contact surface on the elastic contact beam. In these embodiments, the contact bump and the guide portion of the contact surface both protrude downward transversely, that is, toward the bottom portion of the receptacle, into the receptacle. The elastic contact beam may extend along the insertion axis. The elastic contact beam may have a straight primary shape. The elastic contact beam may have a primary shape including a front portion that can extend toward the bottom portion in the insertion direction. In these embodiments, the front portion flares outward toward the opening to facilitate the insertion of the male blade terminal. The elastic contact beam may further include a rear portion that can extend away from the bottom portion in the insertion direction. The elastic contact beam may further include a beam apex that can be located between the front portion and the rear portion. This may provide an advantageous arrangement of the guide portion provided by the bend portion in the elastic contact beam. Alternatively or additionally, the guide portion may be provided by additional surface features on the elastic contact beam.

[0008] The contact beam may have a bump apex located behind the beam apex in the insertion direction. The bump apex may be located at least 0.05 mm behind the beam apex. Preferably, the bump apex may be located at least 0.1 mm behind the beam apex. For example, the bump apex may be at least 0.1 mm, at least 0.15 mm, at least 0.2 mm, at least 0.25 mm, at least 0.3 mm, or at least 0.35 mm behind the beam apex in the insertion direction. This offset may provide an advantageous distance at which a transition is realized between the line contact provided by the guide portion and the point contact provided by the contact bump. The beam apex may define the leading edge of the guide portion. The beam apex may have a partially cylindrical outer surface shape. The radius of curvature of the partially cylindrical outer surface shape may be 0.2 mm to 2 mm, preferably 0.2 mm to 1.2 mm.

[0009] At least one contact surface may include a bottom contact surface on the bottom portion. The guide portion may include a ramp. The ramp may have a front end adjacent to the bottom portion. The ramp may have a rear end adjacent to the bump apex of the contact bump. By providing the guide portion as a ramp, the contact interface between the male blade terminal and the contact surface can be progressively transitioned from line contact at the front end of the ramp toward point contact at the bump apex. Providing the ramp may also allow the contact surface of the bottom portion to be formed by a convenient manufacturing process such as stamping.

[0010] The upper surface of the ramp can define a ramp angle in the insertion direction from the front end to the rear end, which is substantially constant. The height of the upper surface of the ramp can increase linearly from the front end to the rear end. The upper surface of the ramp can have a first width at the front end and a second width at the rear end. The first width may be greater than the second width. This allows the contact interface between the male blade terminal and the bottom contact surface to gradually transition from a line contact at the front end of the ramp to a narrower line contact at the rear end of the ramp, thereby facilitating the transition to a point contact at the bump apex. The upper surface of the ramp may tapere linearly from the first width to the second width. The first width may extend across at least 40% of the width of the bottom portion, preferably at least 50% of the width of the bottom portion. The ramp angle may be any suitable angle. In certain embodiments, the ramp angle is 20 degrees or less from the insertion axis.

[0011] The guide portion may be spaced apart from the contact bump. The guide portion may be contiguous with the contact bump. The guide portion may intersect the forward region of the contact bump. The guide portion may intersect the forward region at an intersection boundary where the contact bump has a first gradient in the insertion direction and the guide portion has a second gradient in the insertion direction. The first gradient and the second gradient may be substantially the same. That is, the guide portion may extend from the contact bump tangentially to the contact bump at the intersection boundary. This may provide a smooth transition between the guide portion and the contact bump. The external shape of the contact bump may be partially spherical.

[0012] At least one contact surface may comprise a single contact surface in the form of a bottom contact surface provided on a bottom portion according to any of the embodiments discussed above. At least one contact surface may comprise a single contact surface in the form of an upper contact surface provided on an elastic contact beam according to any of the embodiments discussed above. In certain arrangements, at least one contact surface comprises a bottom contact surface provided on a bottom portion according to any of the embodiments discussed above and an upper contact surface provided on an elastic contact beam according to any of the embodiments discussed above.

[0013] The female receptacle terminal may include a body having a connection section. The connection section may be configured to couple to a conductor. The body may further include a contact section that may be configured to provide an electrical connection to a matching male blade terminal. The contact section may include an elastic contact beam. The female receptacle terminal may further include a cover. The contact section of the body may be received within the cover to define the receptacle of the female receptacle terminal. In other embodiments, the female receptacle terminal may include a single integrated structure.

[0014] The contact section of the body may further include a stationary beam. The stationary or stationary beam may extend in the insertion direction and may oppose the elastic contact beam. The stationary or stationary beam may define at least a portion of the bottom part of the receptacle.

[0015] The contact surface on the lower portion can be provided on the stationary beam.

[0016] The bottom portion of the receptacle may be at least partially defined by the bottom wall of the receptacle. If the female receptacle terminal includes a cover, the bottom wall of the receptacle may be defined by the bottom wall of the cover. A bottom contact surface may be provided on the bottom wall.

[0017] The upper portion of the receptacle may be at least partially defined by the top wall of the receptacle. If the female receptacle terminal includes a cover, the top wall of the receptacle may be defined by the top wall of the cover. The cover may further include a reinforcing beam formed in the top wall. The reinforcing beam may be cantilevered from a point on the top wall and bent downward toward the elastic contact beam. The reinforcing beam may be configured to provide increased resistance to upward deflection of the elastic contact beam during mating. The reinforcing beam may be configured to provide increased normal force provided by the elastic contact beam to provide a superior electrical connection. The cover may further include a support beam formed in the top wall and positioned directly above the reinforcing beam. The support beam may be cantilevered from a point on the top wall and bent downward toward the elastic contact beam. The support beam may be configured to further increase resistance to upward deflection of the elastic contact beam during mating. The support beam can be configured to further increase the normal force provided by the elastic contact beam to provide an excellent electrical connection.

[0018] At least one contact surface may include a conductive material and may include a plating layer deposited on the conductive material. The plating layer may be formed of any suitable material. For example, the plating layer may be a tin plating layer, a silver plating layer, or a gold plating layer.

[0019] The plating layer can have any suitable thickness. In some arrangements, the plating layer is a tin plating layer having a thickness of 2.5 microns to 4.0 microns.

[0020] The conductive material may be formed from any suitable electrically conductive material. The conductive material may include copper. The conductive material may include a copper alloy or be a copper alloy alone. At least one contact surface may include an intermediate layer between the conductive material and the plating layer. The intermediate layer may be formed from any suitable material. The intermediate layer may include nickel. In some configurations, the intermediate layer may be nickel or a nickel alloy alone.

[0021] According to another embodiment, a female receptacle terminal for an electrical connector is provided, and the female receptacle terminal comprises any or all of the following features: a receptacle - the receptacle has an opening configured to receive a male blade terminal into the receptacle in an insertion direction along the insertion axis -; an elastic contact beam extending from an upper portion of the receptacle toward an opposing lower portion of the receptacle; and at least one contact surface configured to engage with the male blade terminal during insertion of the male blade terminal into the receptacle, the at least one contact surface being provided on at least one of the elastic contact beam and the lower portion, protruding laterally into the receptacle and configured to engage with the male blade terminal along a line contact interface during insertion of the male blade terminal; and a contact bump protruding laterally into the receptacle and configured to engage with the male blade terminal at a point contact interface when the male blade terminal is matched with the female receptacle terminal.

[0022] The guide portion can be positioned closer to the opening than to the contact bump. In this way, during the insertion of the male blade terminal into the receptacle, the guide portion can engage with the male blade terminal before the contact bump. This allows the contact surface to engage with the male blade terminal at the line contact interface before engaging with the male blade terminal at the point contact interface.

[0023] According to another embodiment, a female receptacle terminal for an electrical connector is provided, the female receptacle terminal comprises any or all of the following features: a receptacle - the receptacle has an opening configured to receive a male blade terminal having a predefined tip shape into the receptacle in the insertion direction along the insertion axis -; an elastic contact beam having a contact bump extending from the upper portion of the receptacle toward the opposing lower portion of the receptacle and protruding into the receptacle; and at least one contact surface configured to engage with the male blade terminal during insertion of the male blade terminal into the receptacle, wherein the elastic contact beam is configured to engage with the predefined tip shape at an initial contact interface having an angle of 20 degrees or less with respect to the insertion axis during insertion of the male blade terminal into the receptacle.

[0024] In certain embodiments, the angle or "attack angle" at the contact interface is 16 degrees or less with respect to the insertion axis. In certain embodiments, the angle is 10 degrees or less with respect to the insertion axis. For a given normal force acting on a male blade terminal from at least one contact surface, the attack angle can be optimized to reduce or eliminate wear depending on the specific application of the electrical connector.

[0025] According to another embodiment, a female receptacle terminal for an electrical connector is provided, and the female receptacle terminal comprises any or all of the following features: a receptacle - the receptacle has an opening configured to receive a male blade terminal into the receptacle in an insertion direction along the insertion axis -; an elastic contact beam extending from an upper portion of the receptacle toward an opposing lower portion of the receptacle; and at least one contact surface configured to engage with the male blade terminal during insertion of the male blade terminal into the receptacle, wherein the at least one contact surface is provided on at least one of the elastic contact beam and the lower portion and is configured to reduce wear of the male blade terminal during insertion.

[0026] The receptacle may be configured to receive a male blade terminal having a predefined tip shape. At least one contact surface may be configured to engage with the predefined tip shape. The predefined tip shape may have a flat upper and / or flat lower contact surface. The surfaces of the predefined tip shape may be flat in the sense that they have no curvature along the width of the male blade terminal, that is, they have no curvature in the direction perpendicular to the longitudinal axis of the male blade terminal. The predefined tip shape may be tapered along a length of 1.5 mm or less. In certain embodiments, the predefined tip shape may be tapered along a length of 1.2 mm or less. As used herein, the term “tapered” means that the thickness of the male blade terminal gradually decreases in the height direction toward its nose or tip end. The distance over which the taper extends is defined as the dimension in the insertion direction from the extreme tip end to the point where the thickness of the male blade terminal no longer decreases. This can be a point where both the upper and lower contact surfaces of the male blade terminal are flat.

[0027] Additionally, the present specification discloses a male blade terminal for an electrical connector, wherein the male blade terminal comprises any or all of the following features: a conductive material; a tin plating layer having a thickness of 2.5 microns to 7 microns, preferably 5 microns to 7 microns; and an intermediate layer between the conductive material and the tin plating layer.

[0028] The male blade terminal may include a predefined tip shape as described above. The predefined tip shape may have a flat upper and / or flat lower contact surface. The surfaces of the predefined tip shape may be flat in the sense that they have no curvature along the width of the male blade terminal. The predefined tip shape may be tapered along a length of 1.5 mm or less. In certain embodiments, the predefined tip shape may be tapered along a length of 1.2 mm or less.

[0029] The conductive material may be formed from any suitable electrically conductive material. The conductive material may include copper. The conductive material may be a copper alloy. The intermediate layer may include nickel. The intermediate layer may be formed from nickel or a nickel alloy. The intermediate layer may have a thickness of 1.0 micron to 1.8 micron.

[0030] According to additional embodiments, an electrical connector is provided comprising a female receptacle terminal according to any of the embodiments discussed above and a male blade terminal configured to be received within the receptacle.

[0031] According to another embodiment, a method for forming an electrical connection is provided, the method comprising any or all of the following steps: providing a female receptacle terminal - the female receptacle terminal comprises: a receptacle - the receptacle has an opening configured to receive a male blade terminal into the receptacle in an insertion direction along the insertion axis -; an elastic contact beam extending from an upper portion of the receptacle toward an opposing lower portion of the receptacle; and at least one contact surface configured to engage with the male blade terminal during insertion of the male blade terminal into the receptacle, wherein the at least one contact surface is provided on at least one of the elastic contact beam and the lower portion -; and inserting the male blade terminal into the receptacle - the insertion step is performed by engaging the male blade terminal with at least one contact surface along a line contact interface and then engaging the male blade terminal with at least one contact surface at a point contact interface. Brief explanation of the drawing

[0032] Further features and advantages of the present invention will become apparent from the following description of embodiments thereof, which are presented merely as examples and with reference to the drawings: FIG. 1 is a perspective view of a female receptacle terminal according to the present disclosure. Figure 2 is an exploded view of the terminal according to Figure 1. Figure 3 is a partial cross-sectional view of the terminal of Figure 1. Figure 4 is a perspective view of the terminal of Figure 1. Figure 5 is a bottom view of the contact beam of the terminal of Figure 1. Figure 6 is an upper perspective view of the fixed beam of the terminal of Figure 1. FIG. 7 is a cross-sectional view of another according to the present disclosure. FIG. 8 is a cross-sectional view of a male blade terminal according to the present disclosure. FIG. 9a is a schematic cross-sectional view of a male blade terminal inserted into a female receptacle terminal at a first position. FIG. 9b is a schematic cross-sectional view of a male blade terminal inserted into a female receptacle terminal at a second position. FIG. 10a is a diagram illustrating the force against deflection of typical electrical connectors. FIG. 10b is a drawing illustrating a force against deflection of an electrical connector according to the present disclosure. Specific details for implementing the invention

[0033] As required, detailed embodiments of the present disclosure are provided herein; however, it should be understood that the disclosed embodiments are merely exemplary of the present disclosure, which may be embodied in various forms. Accordingly, the specific details disclosed herein should not be interpreted as limiting, but merely as a basis for the claims and as a representative basis for instructing those skilled in the art to make various uses of the present disclosure.

[0034] FIGS. 1 and 2 illustrate a female receptacle terminal (10). The female receptacle terminal (10) comprises a receptacle having an insertion axis (35) and an opening (20). The opening (20) is configured to receive a male blade terminal (not shown) into the receptacle along the insertion axis (35) in a matching or insertion direction (M). In the illustrated arrangement, the terminal (10) comprises a body (80) having a connecting section (84) at an end portion of the terminal (10) to be coupled to a conductor; a contact section (82) for providing an electrical connection to the male blade terminal; and a cover (30) surrounding the contact section (82) of the body (80). The cover (30) provides retention and reinforcement of the body (80) when the body (80) is inserted therein. Although these components are exemplified as being separable, it will be understood that the body (80) and the cover (30) may instead be formed as a single integral component to provide the terminal (10).

[0035] The body (80) is formed longitudinally along the axis (35). The end of the connecting portion (84) is generally located at the rear or first end of the body (80), and the contact portion (82) is located at the front or second end of the body (80). The body (80) may be stamped and formed from a single piece of an electrically conductive material, such as copper or any other copper-based alloy, or a similar material having comparable electrically conductive properties. In the illustrated arrangement, the connecting portion (84) is "U" shaped and includes a first pair of wings (88) positioned adjacent to the contact portion (82) and a second pair of wing portions (89) positioned adjacent to the first pair of wing portions (88). The wings of the first pair (88) may be used to secure a bare conductor portion of a cable (not shown), and the wings of the second pair (89) may be used to secure an insulated portion of the cable.

[0036] The cover (30) may be stamped and formed from a flat plate and may include a periphery that is generally rectangular. The periphery may include a lower section (22), a pair of side walls extending from the lower section (22), and an upper section (24). In the arrangement of FIG. 2, the cover (30) includes an intermediate wall (26) defining the upper section (24) and the lower section (22). An opening (20) for receiving a matching male terminal may be provided at one end of the lower section (22). In the illustrated arrangement, both the lower section (22) and the upper section (24) extend along the insertion axis (35) and along the length of the cover (30).

[0037] The female receptacle terminal (10) includes an elastic contact beam (100) extending from the upper portion of the receptacle toward the lower portion of the receptacle. In the illustrated arrangement, the upper portion is provided by the upper section (24) and the lower portion is provided by the lower section (22). As best illustrated in FIG. 2, the elastic contact beam (100) may extend from the body (80) and may be configured to be slidably received by the cover (30) when the connecting portion (82) of the body (80) is inserted therein.

[0038] At least one contact surface is provided to engage with a male blade terminal during insertion into the receptacle. In the illustrated arrangement, a contact surface (103) is provided on an elastic contact beam (100). In particular, the contact surface is positioned on the underside of the elastic contact beam (100) so as to face the bottom portion of the receptacle.

[0039] Other contact surfaces may be provided on the bottom portion of the receptacle instead or additionally. In the illustrated arrangement, the contact surface (113) is provided on the upper side of the bottom portion of the receptacle, more specifically on the stop or fixed beam (110) of the female receptacle terminal (10). The stop beam (110) may extend from the body (80) and may be configured to be slidably received by the cover (30) when the connecting portion (82) of the body (80) is inserted therein. In this way, the contact surfaces (103, 113) may be provided on one or both sides of the receptacle to engage with the male blade terminal received by the receptacle.

[0040] As illustrated in FIG. 2, the contact beam (100) and the stop beam (110) extend along the insertion axis (35) and are formed from the base (83). From the base (83), the stop beam (110) extends forward along the insertion axis (35) in a flat manner, and the elastic contact beam (100) extends from the upper portion of the base and faces the stop beam (110). The side wall of the base (83) extends over the elastic contact beam (100) and includes a stop edge (85). The stop edge (85) defines a surface perpendicular to the insertion axis (35) to limit the extent to which the body (80) can be inserted into the cover (30) along the insertion axis (35).

[0041] As illustrated in FIG. 1, the body (80) can be slidably received by the cover (30) in its lower section (22) at the end facing the opening (20). When inserted, the stop beam (110) can be positioned on the lower section (22) of the cover (30).

[0042] A retention beam (40) may be formed within the cover (30). In the illustrated arrangement, the retention beam (40) extends outwardly and is bent and cantilevered from the upper section (24) of the cover (30). The cover (30) may also include a reinforcing beam (50) formed from an intermediate wall (26) to provide additional support to the elastic contact beam (100). The cover (30) may also include a support beam (52) laminated on top of the reinforcing beam (50) to provide additional support to the elastic contact beam (100). This provides increased resistance to deflection during alignment and increases the normal force. By using a higher tensile strength material for the cover (30), the normal force may be further increased.

[0043] FIGS. 3 through 6 illustrate additional details of an elastic contact beam (100) and a stop beam (110) according to one embodiment. In the illustrated arrangement, when the body (80) is inserted into the cover (30), the stop beam (110) defines the bottom portion of the receptacle adjacent to the lower section (22) of the cover (30). Additionally, the elastic contact beam (100) may extend along the receptacle in the insertion direction (M) and may have a primary shape including a front portion, a rear portion, and a beam apex.

[0044] The front portion (100a) extends toward the bottom portion in the insertion direction (M). In the illustrated arrangement, the front portion (100a) is positioned at the free end of the cantilevered contact beam (100) and extends toward the stop beam (100) in the insertion direction (M). That is, the elastic contact beam (100) has a front portion (100a) that is inclined downward toward the stop beam (110) with respect to the insertion direction (M).

[0045] The rear portion (100b) extends away from the bottom portion of the receptacle in the insertion direction (M). In the embodiment illustrated in FIG. 3, the rear portion (100b) extends away from the stop beam in the insertion direction (M). That is, the elastic contact beam (100) has a front portion (100b) that is inclined upward away from the stop beam (110) with respect to the insertion direction (M).

[0046] The beam apex (100c) connects the front portion (100a) and the rear portion (100b). As illustrated in FIGS. 3 through 5, the beam apex (100c) can provide a smooth transition between the downwardly sloped front portion (100a) and the upwardly sloped rear portion (100b) of the contact beam (100). In this way, the elastic contact beam (100) can have a convex shape with respect to the bottom portion of the receptacle.

[0047] In the equilibrium position of the elastic contact beam (100), that is, when the elastic contact beam (100) is not displaced by any male blade terminal, the front portion (100a) may be inclined upward from the beam apex (100c) toward the opening (20) at any suitable angle with respect to the insertion axis (35), for example, 5 to 70 degrees, and the rear portion may be extended upward from the beam apex (100c) toward the insertion direction (M) at any suitable angle, for example, 2 to 30 degrees. In the illustrated arrangement, the front portion (100a) is extended at an angle of approximately 45 degrees with respect to the insertion axis (35), and the rear portion (100b) is extended at an angle of approximately 10 degrees with respect to the insertion axis (35). In the illustrated arrangement, the front portion (100a) is closer to the opening (20) than the rear portion (100b).

[0048] The contact surface (103) of the elastic contact beam (100) includes a contact bump (105). The contact bump (105) protrudes into the receptacle and has an external shape that is curved in both the insertion direction (M) and the width direction of the receptacle. That is, the contact bump is non-linear in both the insertion direction (M) and the width direction, which is perpendicular to the insertion direction (M) and parallel to the plane of the bottom portion of the receptacle. In the illustrated arrangement, the contact bump (105) has at least a partially spherical surface. In other arrangements, the surface may be at least partially elliptical or oval.

[0049] The contact bump (105) may have a bump apex (106) located at the rear of the beam apex (100c) in the insertion direction (M). The bump apex (106) may be provided as the outermost point on the contact bump (105) with respect to the rear portion (100c). That is, the bump apex (106) is a point on the surface of the contact bump (105) at a maximum vertical distance from the outer surface of the rear portion (100a) of the elastic contact beam (100). The bump apex (106) may be located at least 0.25 mm rear of the beam apex (100c). Preferably, the bump apex (106) is located at least 0.35 mm rear of the beam apex (100c).

[0050] The contact surface (103) may also include a guide portion (101). In the illustrated arrangement, the guide portion (101) protrudes into the receptacle and has an external shape that is linear in the width direction and parallel to the bottom portion of the receptacle in a plane perpendicular to the insertion direction (M). That is, the guide portion (101) does not have curvature in the width direction and is not inclined about the insertion axis (35).

[0051] The beam apex (100c) may define the leading edge of the guide portion (101). In the illustrated arrangement, the beam apex (100c) has a partially cylindrical outer surface shape. The radius of curvature of the partially cylindrical surface shape is preferably 0.2 mm to 2 mm, more preferably 0.2 mm to 1.2 mm. The guide portion (101) may be positioned closer to the opening (20) than to the contact bump (105). In this way, during the insertion of the male terminal blade into the receptacle through the opening (20), the guide portion (101) engages with the male blade terminal before engaging with the contact bump (105).

[0052] As best illustrated in FIGS. 4 and 6, a contact surface (113) on the bottom portion of the receptacle may be provided on a stop beam (110). The contact surface (113) may include a contact bump (115) having an external shape that protrudes into the receptacle and is curved in both the insertion direction and the width direction of the receptacle. That is, the contact bump is non-linear in both the insertion direction (M) and the width direction perpendicular to the insertion direction (M) and parallel to the plane of the bottom portion of the receptacle. In the illustrated arrangement, the contact bump (115) has at least a partially spherical surface. In other arrangements, the surface may be at least partially elliptical or oval.

[0053] The contact bump (115) may have a bump apex (116). The bump apex (106) may be provided as the outermost point on the contact bump (115) with respect to the surface of the stationary beam (110). That is, the bump apex (116) is a point on the surface of the contact bump (115) at a maximum vertical distance from the planar surface of the stationary beam (110).

[0054] The contact surface (113) may also include a guide portion (111). In the illustrated arrangement, the guide portion (111) protrudes into the receptacle and has an external shape that is linear in the width direction and parallel to the bottom portion of the receptacle in a plane perpendicular to the insertion direction (M). That is, the guide portion (111) does not have curvature in the width direction and is not inclined about the insertion axis (35).

[0055] As best illustrated in FIG. 6, the guide portion (111) of the illustrated arrangement comprises a ramp having a front end (111a) adjacent to the front end of the stop beam (110) and a rear end (111b) adjacent to the bump apex (116) of the contact bump (115). The upper surface of the ramp increases in height linearly from the front end (111a) to the rear end (111b). The angle of the ramp with respect to the insertion direction is preferably less than 20 degrees, and may be less than 15 degrees or less than 10 degrees. In the illustrated arrangement, the ramp angle is approximately 7 degrees. The upper surface of the ramp has a first width at the front end (111a) and a second width at the rear end (111b), where the first width is greater than the second width. The first width and the second width are measured in the width direction perpendicular to the insertion direction (M). The upper surface of the ramp tapers linearly from the first width to the second width. In the illustrated arrangement, the ramp has a substantially triangular upper surface. The first width may extend across at least 40%, preferably at least 50%, of the width of the lower portion.

[0056] At least a portion of the guide portion (111) may overlap with the axial range of the contact bump (115). In particular, the ramp portion of the guide portion (111) may overlap with the contact bump (115). In the illustrated arrangement, the rear end (111b) of the ramp (111) is located at least 20% of the axial range of the contact bump (115) in the insertion direction (M). In other examples, the rear end (111b) of the ramp (111) may be located at least 30% or at least 40% of the axial range of the contact bump (115) in the insertion direction (M). Referring to FIGS. 4 and 6, the upper surface of the guide portion (111) contacts the spherical surface of the contact bump (115). That is, the gradient of the spherical surface at the point where the contact bump (115) meets the rear end (111b) of the guide portion (111) may be the same as the gradient of the upper surface of the guide portion (111) to provide a smooth transition between the guide portion (111) and the contact bump (115).

[0057] In the vertical direction of FIG. 3 (perpendicular to the insertion axis (35)), the minimum gap between the contact bump (105) on the elastic contact beam (100) and the contact bump (115) on the stationary beam (110) may be any suitable distance according to a number of factors including, but not limited to, the desired application of the connector, the size of the corresponding male blade terminal and / or the stiffness of the elastic contact beam (100). In some arrangements, the minimum gap between opposing contact bumps is in the range of 0.1 mm to 0.3 mm, for example, 0.17 mm.

[0058] The bump apex (116) of the stationary beam (110) may be offset axially from the bump apex (106) of the elastic contact beam (100) by any suitable distance according to the factors described above (i.e., offset in the direction of the insertion axis (35). The offset may be in the insertion direction or in the removal direction along the insertion axis (35). In the arrangement shown in FIG. 3, the apex of the contact bump (105) on the elastic contact beam (100) is offset in the insertion direction (M) (i.e., further away from the opening (20)) from the apex of the contact bump (115) on the stationary beam (110). In other arrangements, the apex of the contact bump (115) on the stationary beam (110) is offset in the insertion direction (M) from the apex of the contact bump (105) on the elastic contact beam (100). In some arrangements, the bump vertices (106, 116) may be offset by a distance of 0 mm to 1 mm, for example, 0 mm to 0.5 mm. The offset may be approximately 0.2 mm. It will be understood that when the offset is 0 mm, the bump vertices are axially aligned.

[0059] The front end of the stop beam (110), i.e., the end closest to the opening (20), may have a chamfered edge (90). At least one of the contact surfaces (103, 113) of the female receptacle terminal (10) comprises a conductive material and a plating layer deposited on the conductive material. In one embodiment, the plating layer preferably comprises tin having a thickness of 2.5 microns to 4 microns. The plating layer is preferably formed by a matte plating process. The conductive material may comprise copper or a copper alloy, and a nickel intermediate layer may be formed between the conductive material and the plating layer. The plating layer may preferably be coated on a lubricating layer.

[0060] FIG. 7 illustrates an embodiment of a female receptacle terminal comprising a receptacle having an opening (20) configured to receive a male blade terminal (not shown) into the receptacle along an insertion axis and an insertion direction (M) along the insertion axis. The female receptacle terminal of FIG. 7 is similar in structure and operation to the embodiment of the female receptacle terminal discussed above in relation to FIG. 1 through 6, and similar reference numerals are used to indicate similar features. Similar to the embodiment illustrated in FIG. 1 through 6, the receptacle comprises an elastic contact beam (200) extending from the upper portion of the receptacle toward the opposing lower portion of the receptacle. The lower portion may be defined by a fixed or stop beam (210). In the illustrated arrangement, the elastic contact beam (200) comprises a front portion (200a) extending toward the bottom portion of the receptacle in the insertion direction (M), a rear portion (200b) extending away from the bottom portion in the insertion direction (M), and a beam apex (200c) located between the front portion (200a) and the rear portion (200b). The terminal comprises at least one contact surface configured to engage with a male blade terminal during insertion into the receptacle. At least one contact surface is provided on at least one of the elastic contact beam (200) and the bottom portion. In the illustrated arrangement, a contact surface (203) is included on the elastic contact beam (200), and another contact surface (213) is included on the stationary beam (210). The description of the contact surfaces (103, 113) related to FIGS. 3 through 6 is applicable to the present embodiment.

[0061] The main difference between this arrangement and the arrangements of FIGS. 1 through 6 is that in the arrangement of FIG. 7, the free end of the elastic contact beam (200) is positioned at the end of the rear portion (200b) and at the opposite end to the front portion (200a) of the elastic contact beam (200). The elastic contact beam (200) is secured to the upper portion of the receptacle by a mounting portion (200d). In the illustrated arrangement, the mounting portion (200d) is connected to the front end of the front portion (200a) adjacent to the opening (20).

[0062] FIG. 7 also illustrates some dimensions of a receptacle arrangement when it is in a balanced position, that is, when there are no male blade terminals inserted into the receptacle. The height of the gap between the contact surface (203) on the elastic contact beam (200) and the contact surface (213) on the stationary beam (210) is indicated by label L1. In particular, L1 is the height of the gap measured in the vertical direction (i.e., perpendicular to the insertion direction (M)) from the apex (206) of the contact bump on the contact surface (203) to the apex (216) of the contact bump on the opposing contact surface (213). The gap (L1) may be any suitable distance depending on the desired application. In some arrangements, LI is 0.35 mm to 0.50 mm, or 0.40 mm to 0.45 mm. L1 may be approximately 0.43 mm. These dimensions of L1 may apply equally to the embodiments of FIG. 1 through 6.

[0063] In FIG. 7, the bump apex (206) is located behind the beam apex (200c). The distance in the insertion direction (M) from the beam apex (200c) to the bump apex (206) is indicated by label L2. Preferably, L2 is at least 0.25 mm, and more preferably, L2 is at least 0.35 mm. That is, in some embodiments, the bump apex (206) may be located at least 0.25 mm behind the beam apex (200c), preferably at least 0.35 mm behind the beam apex (200c).

[0064] As illustrated in FIG. 7, dimension L3 represents a clearance in the vertical direction (i.e., perpendicular to the insertion direction (M)) between the upper portion of the receptacle and the upper surface of the free end of the elastic contact beam (200). Preferably, L3 is 0.06 mm to 0.25 mm, and more preferably, L3 is approximately 0.18 mm. As described below, dimension L3 is a factor that determines the normal force applied by the elastic contact beam (200) on the male blade terminal inserted therein.

[0065] FIG. 8 schematically illustrates a cross-sectional view of the tip (302) of a male blade terminal (300) configured to be connected to a female receptacle terminal (10). In the illustrated arrangement, the tip (302) has a predefined tip shape comprising a smooth convergence having a cut end face (304) at its distal end. A portion of the male blade terminal (300) is in close proximity to the tip (302), and along this, the outer surfaces of the male blade terminal are parallel to its longitudinal axis. It will be understood that when the male blade terminal (300) is inserted into the female receptacle, the longitudinal axis of the male blade terminal (300) will be substantially parallel to the insertion axis. Accordingly, the convergence provides a taper along the length of the male blade terminal toward the end face (304), and along this, the thickness of the male blade terminal, i.e., the maximum dimension in the vertical direction, decreases. The predefined tip shape may taper along a length of less than 1.5 mm.

[0066] The external contact surfaces of the tip (302) are configured to contact the contact surfaces (103, 113) of the female receptacle terminal. Although not shown in the drawings, the male blade terminal (300) is preferably of a type having a rectangular or square cross-section such that the upper surface (305) is configured to contact the first contact surface (103) of the female receptacle terminal, and the lower surface (306) facing the first surface is configured to contact the second contact surface (113). The predefined tip shape may have flat upper and / or flat lower contact surfaces. The surfaces of the predefined tip shape may be flat in the sense that they have no curvature along the width of the male blade terminal, that is, they have no curvature in the direction perpendicular to the longitudinal axis of the male blade terminal and perpendicular to the height direction of the male blade terminal. Specifically, the upper contact surface and the lower contact surface may be linear in the width direction and parallel to each other in a plane perpendicular to the longitudinal axis of the male blade terminal.

[0067] The steepest slope of the surfaces (305, 306) occurs at the end of the male blade terminal (300) illustrated in FIG. 8, that is, at the point where the surfaces (305, 306) meet the end surface (304). At the end, the upper and lower surfaces (305, 306) each form an angle with respect to the longitudinal axis of the male blade terminal (300). The angle is preferably less than 30 degrees or less than 25 degrees. In the illustrated arrangement, the angle is approximately 20 degrees. The slope of the surfaces (305, 306) gradually decreases as they move away from the end surface (304) until they are parallel to the insertion axis (35)—at this point, the slope of each surface (305, 306) is 0.

[0068] In the illustrated arrangement, the male blade terminal (300) comprises a conductive material (310) that may comprise copper or a copper alloy. Preferably, a plating layer (314) comprising tin is provided on at least a portion of the outer surface of the tip (302). The male blade terminal (300) further comprises an intermediate layer (312) preferably comprising nickel. The intermediate layer (312) is disposed between the conductive material (310) and the plating layer (314). A lubricating layer may also be provided on the plating layer.

[0069] FIGS. 9a and 9b schematically illustrate the interaction between the outer surfaces (305, 306) of the male blade terminal (300) and the contact surfaces (103, 113) of the female receptacle terminal (10) as the male blade terminal (300) is inserted inside. Although the matching interaction is described with reference to the arrangement of FIGS. 3 through 6, it will be understood that the male blade terminal (300) interacts with the female receptacle terminal of FIG. 7 in substantially the same way. As the male blade terminal (300) is inserted into the opening (20) of the receptacle, its outer surfaces (305, 306) come into contact with the corresponding contact surfaces (103, 113) of the female terminal. As clearly illustrated in FIGS. 9a and 9b, the height of the gap between the contact bumps (105, 115) is too small to allow the entire height of the blade (300) to be fitted through it. While the stationary beam (110) remains fixed in place relative to the lower section (22) of the receptacle, the normal force applied by the blade (300) to the elastic contact beam (100) causes the latter to be deflected upward relative to its equilibrium position. As the blade (300) is further inserted into the receptacle, the deflection of the elastic contact beam (100) gradually increases. The contact surfaces (103, 113) apply a force to the blade surfaces (305, 306), and the force is a normal force perpendicular to the interface between each pair of contact surfaces.

[0070] As illustrated in FIG. 9a and described above, the contact surfaces or surfaces of the female receptacle terminal may include a guide portion that is linear and horizontal in the width direction (in a plane perpendicular to the insertion direction), and a contact bump that is curved in both the width direction and the insertion direction. Additionally, the male blade terminal may have a substantially rectangular cross-section with inclined surfaces and may be inserted into the receptacle such that its outer surfaces have a similar shape in the width direction of the guide portion. Thus, when a surface, e.g., the upper surface (305), contacts the guide portion (101) of the contact beam (100), the contact interface between them will be linear because they are linear in the width direction and parallel to the bottom portion of the receptacle in a plane perpendicular to the insertion direction. That is, the male blade terminal will engage with the contact surface (103) along the line contact interface. This distributes normal force along the line instead of initially concentrating force at a single point. The same applies to the guide portion (111) of the stationary beam (110). Accordingly, in the illustrated arrangement, this line contact is established when the upper surface (305) is coupled with the guide portion (101) of the elastic contact beam (100), and when the lower surface (306) is coupled with the guide portion (111) of the stop beam (110) provided on the bottom portion of the receptacle.

[0071] As illustrated in FIG. 9b and described above, a contact bump on one or both of the contact surfaces (103, 113) engages with a male blade terminal after the guide portion. The contact bump is curved in both the width direction and the insertion direction, which can provide an external surface shape that is convex to the receptacle. Thus, when a surface, e.g., an upper surface (305), contacts the contact bump (105) of the elastic contact beam (100), considering the linear shape in the width direction of the external surfaces (305, 306) of the blade (300) compared to the curved shape of the contact bump (105), the contact interface between them will be a single point. That is, the male blade terminal will engage with the contact surface (103) at a point contact interface. In the same way, the external surface (306) will engage with the contact bump (115) of the stationary beam (110) at a point contact interface.

[0072] In some prior arrangements, the first contact between the male blade terminal and the female receptacle terminal occurs near the end face of the male blade terminal, i.e., at a point-contact interface with a greater surface gradient. This causes higher shear stress on the contact surfaces, leading to increased pile-up of plating material on the male blade terminal, which ultimately results in increased wear and associated increased and / or unpredictable insertion forces during subsequent mating operations.

[0073] By arranging the female receptacle terminal and the male blade terminal according to the present disclosure, a normal force is distributed at a first contact point across the surfaces (305, 306) of the male blade terminal (300), thereby reducing the deterioration of the contact surfaces. However, at the shallower or flatter portions of the male blade terminal (i.e., facing the right side of the male blade terminal (300) in FIG. 9a and 9b), the point contact interface is less harmful to the plating layer. Furthermore, at the shallower or flatter portions, it is preferable that the normal force be applied through a single point rather than a line, because an electrical connection is formed at these portions of the male blade terminal. Increased local pressure applied to the contact surfaces (305, 306) facilitates an improved electrical connection between the male and female components of the electrical connector. This is particularly important when a lubricant is used, because electrons can tunnel more easily through the lubricant layer when the pressure is higher. However, if the normal force is too high at point contact, this can lead to increased wear as the male blade terminal slides further into the receptacle.

[0074] FIG. 7 illustrates one way in which normal force can be controlled. As the male blade terminal is inserted into the opening (20) and comes into contact with the elastic contact beam (200), the elastic contact beam (200) will be deflected upward. The normal force applied to the blade terminal will be determined primarily by the stiffness of the mounting portion (200d). Eventually, as the male blade terminal is further inserted along the insertion direction (M), the elastic contact beam (200) will be deflected upward to the extent that its free end comes into contact with the upper portion. At this point, the elastic contact beam (200) comes into contact with the upper portion of the receptacle at both ends, and further upward deflection will require pressing the beam apex (200c) upward between the two ends of the elastic contact beam (200). It will be understood that this deflection requires more force and thereby increases the normal force applied to the male blade terminal. By adjusting dimension L3 of FIG. 7, the point where increased force is required can be changed accordingly to control the normal force throughout the insertion process.

[0075] Referring to FIG. 9b, another factor that can determine the degree of wear of the contact interface is the angle of attack. The angle of attack can be defined as the angle between the tangent at the contact interface and the insertion axis (35). On the upper surface of the male blade terminal (300) illustrated in FIG. 9b, the angle of attack (AA) is the angle between the tangent (T) at the contact interface (between the upper surface (305) and the corresponding contact bump (105)) and the insertion axis (35). Preferably, the angle of attack (AA) is an acute angle of 20 degrees or less, preferably 16 degrees or less. In the illustrated arrangement, the angle of attack (AA) is approximately 10 degrees.

[0076] FIGS. 10a and FIGS. 10b show the insertion distance ( d Insertion force () regarding ) F)Graphs are illustrated. That is, these graphs show the amount of force required to insert and remove a given male blade terminal into and from a female receptacle terminal as a function of how far the male blade terminal is inserted into the female receptacle terminal. FIG. 10a illustrates force characteristics in known electrical connectors, while FIG. 10b illustrates force characteristics for an electrical connector according to the present disclosure based on data from experimental measurements. The graphs are plotted on the same scale so that the sizes can be directly compared. With respect to the length of the male blade inserted into the receptacle, each graph illustrates a plot of the force required to insert the blade (illustrated above the horizontal axis) and a plot of the force required to remove the blade (illustrated below the horizontal axis) for the first and tenth match / mismatch cycles of the given connector.

[0077] In FIG. 10a, plot (X1) shows the insertion and removal forces during the first insertion / removal cycle, and plot (X10) shows the insertion and removal forces during the tenth insertion / removal cycle of a known connector. In FIG. 10b, plot (Yl) shows the insertion and removal forces during the first insertion / removal cycle, and plot (Y10) shows the insertion and removal forces during the tenth insertion / removal cycle of a connector according to the present disclosure. This shows that, as a result of the wear reduction realized using the electrical connector assembly disclosed herein, the insertion and removal forces during the initial cycle and the tenth cycle are lower than those for known connectors. Furthermore, it can be seen that while plots (Y1, Y10) follow substantially the same force profile, plots (X1, X10) deviate significantly for both insertion and removal. Thus, in addition to allowing for reduced insertion forces, the electrical connector arrangement disclosed herein has a more predictable, consistent, and repeatable force profile.

[0078] Various modifications by addition, deletion and / or substitution may be made to all of the embodiments described above to provide additional embodiments, any and / or all of which are intended to be covered by the appended claims.

Claims

Claim 1 A female receptacle terminal for an electrical connector, wherein the female receptacle terminal comprises: a receptacle—the receptacle having an opening configured to receive a male blade terminal into the receptacle in an insertion direction along the insertion axis—; an elastic contact beam extending from an upper portion of the receptacle toward an opposing lower portion of the receptacle; an upper contact surface on the elastic contact beam configured to engage with the male blade terminal during insertion of the male blade terminal into the receptacle; and a lower contact surface provided on the lower portion, wherein the upper contact surface comprises a contact bump having an external shape that protrudes laterally into the receptacle and is curved in both the insertion direction and the width direction of the receptacle. and includes a guide portion having an external shape that protrudes into the receptacle in the transverse direction, is linear in the width direction in a plane perpendicular to the insertion direction, and is parallel to the bottom portion, wherein the guide portion is positioned adjacent to the contact bump and closer to the opening than to the contact bump, so that during insertion of the male blade terminal into the receptacle, the guide portion engages with the male blade terminal before the contact bump, and the guide portion includes a ramp having a front end adjacent to the bottom portion and a rear end adjacent to the bump apex of the contact bump, wherein the front end is linear in the width direction and is parallel to the bottom portion in a plane perpendicular to the insertion direction, and the elastic contact beam has a primary shape that extends along the insertion axis and includes a front portion extending toward the bottom portion in the insertion direction, a rear portion extending away from the bottom portion in the insertion direction, and a beam apex located between the front portion and the rear portion, and the contact bump of the upper contact surface has a bump apex located behind the beam apex in the insertion direction. Female receptacle terminal. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 A female receptacle terminal according to claim 1, wherein the bump apex of the upper contact surface is located at least 0.1 mm rearward of the beam apex. Claim 6 In claim 1, the beam vertex is a female receptacle terminal defining the leading edge of the guide portion of the upper contact surface. Claim 7 In claim 1, the beam apex has a partially cylindrical outer surface shape having a radius of curvature of at least 0.2 mm to 2 mm, a female receptacle terminal. Claim 8 In claim 1, the upper surface of the lamp defines a lamp angle in the insertion direction from the front end to the rear end, which is substantially constant such that the height of the upper surface of the lamp relative to the bottom portion increases linearly from the front end to the rear end, forming a female receptacle terminal. Claim 9 In claim 1, the upper surface of the lamp has a first width at the front end and a second width at the rear end, wherein the first width is larger than the second width, a female receptacle terminal. Claim 10 In claim 9, the upper surface of the lamp is a female receptacle terminal that taperes linearly from the first width to the second width. Claim 11 In claim 9, the first width extends across at least 40% of the width of the bottom portion, forming a female receptacle terminal. Claim 12 In claim 11, the first width extends across at least 50% of the width of the bottom portion, forming a female receptacle terminal. Claim 13 In claim 8, the female receptacle terminal, wherein the ramp angle is 20 degrees or less with respect to the insertion axis. Claim 14 In claim 1, the guide portion of the bottom contact surface is a female receptacle terminal contiguous with the contact bump of the bottom contact surface. Claim 15 In paragraph 14, the guide portion of the bottom contact surface intersects the front region of the contact bump at an intersection boundary where the contact bump of the bottom contact surface has a first gradient in the insertion direction and the guide portion has a second gradient in the insertion direction, and the first and second gradients are substantially the same, a female receptacle terminal. Claim 16 In claim 1, the external shape of the contact bump is partially spherical, a female receptacle terminal. Claim 17 The female receptacle terminal of claim 1 comprises: a body having a connecting section for coupling to a conductor and a contact section for providing an electrical connection to a matching male blade terminal—the contact section comprising the elastic contact beam—; and a cover in which the contact section of the body is received to define the receptacle of the female receptacle terminal. Claim 18 In claim 17, the contact section of the body further comprises a stationary beam extending in the insertion direction and facing the elastic contact beam, and the stationary beam defines at least a portion of the bottom portion of the receptacle, a female receptacle terminal. Claim 19 In paragraph 18, the bottom contact surface on the bottom portion is a female receptacle terminal provided on the stop beam. Claim 20 A female receptacle terminal according to claim 1, wherein the at least one contact surface comprises a conductive material and a plating layer deposited on the conductive material. Claim 21 In paragraph 20, the plating layer is a tin plating layer, a gold plating layer, or a silver plating layer, a female receptacle terminal. Claim 22 A female receptacle terminal according to claim 21, wherein the plating layer is a tin plating layer having a thickness of 2.5 microns to 4.0 microns. Claim 23 In Clause 20, the above conductive material is a female receptacle terminal made of a copper alloy. Claim 24 In claim 21, the at least one contact surface further comprises an intermediate layer between the conductive material and the plating layer, wherein the intermediate layer is formed of nickel or a nickel alloy, a female receptacle terminal. Claim 25 A female receptacle terminal for an electrical connector, wherein the female receptacle terminal comprises: a receptacle—the receptacle having an opening configured to receive a male blade terminal into the receptacle in an insertion direction along the insertion axis—; an elastic contact beam extending from an upper portion of the receptacle toward an opposing lower portion of the receptacle; an upper contact surface on the elastic contact beam configured to engage with the male blade terminal during insertion of the male blade terminal into the receptacle; and a lower contact surface provided on the lower portion, wherein the upper contact surface protrudes laterally into the receptacle and is configured to engage with the male blade terminal along a line contact interface during insertion of the male blade terminal; A female receptacle terminal comprising a contact bump that protrudes into the receptacle in the transverse direction and is configured to engage with the male blade terminal at a point contact interface when the male blade terminal is matched with the female receptacle terminal, wherein the guide portion comprises a ramp having a front end adjacent to the bottom portion and a rear end adjacent to the bump apex of the contact bump, wherein the front end is linear in the width direction and parallel to the bottom portion in a plane perpendicular to the insertion direction, and the elastic contact beam has a primary shape that extends along the insertion axis and includes a front portion extending toward the bottom portion in the insertion direction, a rear portion extending away from the bottom portion in the insertion direction, and a beam apex located between the front portion and the rear portion, and wherein the contact bump of the upper contact surface has a bump apex located behind the beam apex in the insertion direction. Claim 26 A female receptacle terminal according to claim 25, wherein the guide portion is positioned closer to the opening than the contact bump, so that during insertion of the male blade terminal into the receptacle, the guide portion engages with the male blade terminal before the contact bump. Claim 27 An electrical connector comprising: a female receptacle terminal of any one of claims 1, 25 and 26; and a male blade terminal configured to be received within the receptacle. Claim 28 A method for forming an electrical connection comprising: providing a female receptacle terminal, wherein the female receptacle terminal comprises: a receptacle—the receptacle having an opening configured to receive a male blade terminal into the receptacle in an insertion direction along the insertion axis—; an elastic contact beam extending from an upper portion of the receptacle toward an opposing lower portion of the receptacle; an upper contact surface on the elastic contact beam configured to engage with the male blade terminal during insertion of the male blade terminal into the receptacle; and a lower contact surface provided on the lower portion, wherein the upper contact surface comprises a guide portion protruding laterally into the receptacle and configured to engage with the male blade terminal along a line contact interface during insertion of the male blade terminal; and includes a contact bump that protrudes into the receptacle in the transverse direction and is configured to engage with the male blade terminal at a point contact interface when the male blade terminal is matched with the female receptacle terminal, wherein the guide portion includes a ramp having a front end adjacent to the bottom portion and a rear end adjacent to the bump apex of the contact bump, wherein the front end is linear in the width direction and parallel to the bottom portion in a plane perpendicular to the insertion direction, and the elastic contact beam has a primary shape that extends along the insertion axis and includes a front portion extending toward the bottom portion in the insertion direction, a rear portion extending away from the bottom portion in the insertion direction, and a beam apex located between the front portion and the rear portion, and the contact bump of the upper contact surface has a bump apex located behind the beam apex in the insertion direction.A method comprising the step of inserting the male blade terminal into the receptacle, wherein the insertion step is performed by engaging the male blade terminal with the guide portion of the upper contact surface along the line contact interface and subsequently engaging the male blade terminal with the contact bump of the upper contact surface at the point contact interface.

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