Female terminal for a connector and a housing therefor

A female terminal for a connector comprising a terminal body that is fixed by a retainer of a housing, a leaf spring that extends forward in the terminal body, and a stabilizer that is fixed by a lance of the housing. At the root end of the leaf spring, a round part that bends lengthwise into an approximately circular arc is formed. A bead having a curved section to increase flexural rigidity of the leaf spring is formed ahead of the round part on the top end side. A stabilizer having a face directed in the width direction is erected in the height direction from the top end of the terminal body.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention relates to a connector wherein a female terminal is
 inserted in a chamber of a housing.
 2. Related Art
 A connector has been known, as shown in FIG. 12A, wherein through chambers
 82, in several rows and columns in the directions of height and width, are
 formed in a housing 81 in parallel to each other, a female terminal 84
 being approximately tubular in the front half and being connected to an
 electric wire 83 in the back is inserted into and fixed in each of the
 chambers 82, and male terminals of a counterpart connector are inserted
 into these female terminals 84 to make mechanical connections as well as
 electrical connections (refer to, for example, Japanese Provisional Patent
 Hei 8-106944). A port 85 opens in the front end of the above- mentioned
 female terminal 84 to receive a male terminal. A splicing part 86 is
 formed in the back of the female terminal 84 to connect an electric wire
 83. A concave fixing part 87 is formed in an intermediate part of the
 female terminal 84. A hook of a lance 88 that is flexibly formed in a
 chamber 82 of the housing 81 fits into this concave fixing part 87 to
 provide a primary fixing of the female terminal 84 to the housing 81.
 Moreover, a fixing piece 90 of a retainer 89 that is fitted into the
 housing 81 is set at the back of a stabilizer 91 that is formed on the top
 of the intermediate part of the female terminal 84 to provide a secondary
 fixing of the female terminal 84 to the housing 81.
 Apart from this, a connection structure between a female terminal of this
 kind and a male terminal has been disclosed in Japanese Provisional Patent
 Hei 9-232021. As shown in FIG. 12B, to hold an inserted male terminal 92',
 a leaf spring 93' is integrally formed inside the terminal body 94' of a
 female terminal 84'.
 This leaf spring 93' is blanked out together with the terminal body 94' of
 a sheet metal and formed by bending the blank. When the material and
 thickness of the sheet metal are selected by considering formability,
 cost, etc., it is difficult to secure a sufficient contacting force from
 the single leaf spring 93'. Hence the above-mentioned Japanese Provisional
 Patent Hei 9-232021 has disclosed a technology wherein a separate
 reinforcing leaf spring 95' is blanked out together with the terminal body
 94' and this reinforcing leaf spring 95' is bent on the inner side of the
 main leaf spring 93' to form double springs and ensure a sufficient
 contacting force. In this case, as each of the leaf springs 93', 95' is
 formed by bending, a gap is formed between two unrestricted leaf springs
 due to springbacks. As the dimension of this gap is a cumulative result of
 steps of forming two springs, it is difficult to accurately control this
 dimension in the production. It is hard to avoid dispersion in this gap
 dimension. This poses a problem. At the time of use, the point of
 inflection of the spring constant at which the main spring 93' contacts
 the reinforcing spring 95' and both springs 93', 95' start to be deformed
 varies from product to product. Thus contacting forces are not stable and
 vary from product to product. Moreover, as the two leaf springs 93', 95'
 are overlapped with each other, the female terminal 84' becomes bulkier,
 preventing the ability to make the connector more compact. Furthermore, as
 shown in FIG. 12B, a round part 96' that is bent into an approximately
 circular arc is formed near the root end of the leaf spring 93'. When the
 radius of curvature of this round part 96' is small, cracks may be
 generated in the round part 96' in use as shown in FIG. 12C. If corrosion
 develops from these cracks, the contacting force will become extremely
 unstable.
 The above-mentioned stabilizer 91 can exhibit a function of preventing
 so-called inverse insertion; if the female terminal 84 is inserted into
 the chamber 82 of the housing 81 in an incorrect orientation, for example,
 upside down, the stabilizer 91 will catch the entrance of the chamber 82
 to prevent further insertion. Because of this function, the female
 terminal 84 and the retainer 89 are brought to a proper positional
 relationship and the female terminal 84 is fixed by the retainer 89.
 However, as the stabilizer is to be fixed by a fixing piece 90 of the
 retainer 89, the stabilizer is provided on the top of the intermediate
 part of the terminal body. Accordingly, the front portion of the terminal
 body ahead of the stabilizer 91, even if it is inverted upside down, would
 be inserted. This, in turn, would make the assembly worker forcefully
 insert the female terminal 84 further, resulting in a damage to the
 chamber and nearby portions of the housing 81.
 When a continuity test or the like is to be conducted on to a female
 terminal of a connector, a test jig having a shape identical to that of a
 male terminal is inserted into the female terminal. When the test jig is
 used repeatedly, the jig may be deformed. If such a deformed jig is forced
 into a female terminal, the lead spring, etc. will be damaged and thus
 cause trouble.
 A connector is used in combination with a counterpart connector. Making the
 counterpart connector more compact is also desired. If there is an error
 in assembling a male terminal in the counterpart connector, the male
 terminal may be assembled to be slightly slanted in relation to the
 housing. In the worst case, such a male terminal may cause a trouble that
 it can not be inserted into a female terminal.
 SUMMARY OF THE INVENTION
 The present invention was made in view of the above-mentioned points. One
 objective of the present invention is to ensure a stable and sufficient
 contacting force by forming a bead and increasing the flexural rigidity of
 a leaf spring and using only a single leaf spring, to move a contacting
 part of the leaf spring forward, to reduce the length of insertion of a
 male terminal and make the counterpart connector compact, and to increase
 the tolerance to slant of the male terminal. Another objective is to
 prevent cracks, etc. and stabilize the contacting force by giving a larger
 radius of curvature to the round part in a position beyond the reach of
 the male terminal. Another objective is to reinforce the function of
 preventing inverse insertion of the female terminal by shifting the
 stabilizer forward, and to prevent damage to the leaf spring, etc. by
 making the stabilizer available to a continuity test, etc. of the female
 terminal. Furthermore, another objective is to make the connector more
 compact in the direction of height as much as possible by, in addition to
 using a single leaf spring and shifting the round part backward, flexing a
 lance in the direction of width.
 To accomplish the above-mentioned objectives, the present invention is a
 female terminal that is inserted into a chamber of a housing of a
 connector and receives a male terminal, the female terminal comprising: a
 terminal body having a tubular front half part that can be inserted into
 the chamber of the housing, having a port that opens in the front end and
 receives a male terminal, having a splicing part that is in the back and
 that is connected to an electric wire, and having a fixing part into which
 a retainer of the housing fits; a leaf spring having a root end that is
 integral to the front half of the body, having a top end that extends
 forward inside the front half part of the terminal body, and being adopted
 to be flexed in the direction of height; a stabilizer being erected in the
 direction of height on the outer side at the front end of the terminal
 body, having a face in the direction of width, fitting into a groove
 formed in the longitudinal direction and advancing beyond a lance that is
 formed in the groove and being fixed by the lance when said terminal
 proper is inserted into the chamber of the housing; a round part that is
 formed at the root end of said leaf spring and bent around an axis
 approximately parallel to said front half part into an approximately
 circular arc in a position beyond the reach of said male terminal; and a
 bead that is formed ahead of said round part of said leaf spring on the
 top end side thereof and has a curved section to increase the flexural
 rigidity.
 According to the present invention, when an electric wire is connected to
 the splicing part of the terminal body and the female terminal is inserted
 into a chamber of the housing, the stabilizer will fit into the groove of
 the housing and advance forward beyond the lance of the housing and will
 be fixed by the lance. This is the primary fixing of the female terminal
 to the housing. Next, when a retainer is pushed into the housing, the
 retainer will fit into the fixing part of the terminal body. This is the
 secondary fixing of the female terminal to the housing. When a counterpart
 connector is opposed to the connector and a male terminal of the
 counterpart connector is inserted into the female terminal, the leaf
 spring will be pressed to contact the male terminal to make both
 mechanical connection and electrical connection between the two
 connectors.
 As the bead is formed beyond the round part of the leaf spring on the top
 end side thereof, the flexural rigidity of the leaf spring is greater and
 a sufficient contacting force is provided without provision of a
 reinforcing spring. Moreover, as no reinforcing spring is provided, the
 spring constant has no point of inflection, and the contacting force of
 each product is stabilized. Furthermore, as the flexural rigidity of the
 leaf spring is greater, a sufficient contacting force is generated even if
 a contacting part of the leaf spring is shifted forward close to the port.
 As a result, the length of insertion of a male terminal is shortened, and
 in turn, the housing of the counterpart connector that contains the male
 terminal is shortened and made more compact. Its tolerance to slant of the
 male terminal is also increased. Moreover, as the round part is formed in
 a position beyond the reach of the male terminal, the radius of curvature
 of the round part can be set larger by extensively using the interior of
 the front half part of the terminal body in the direction of height. This
 prevents generation of cracks in the round part and stabilizes the
 contacting force. As the stabilizer is provided at the front end of the
 terminal proper, if the female terminal is inserted into a chamber of the
 housing in a wrong orientation, the stabilizer will catch on the entrance
 of the chamber in the initial stage of insertion. Thus inverse insertion
 of the female terminal is prevented reliably, and any damage to the
 housing due to incorrect operation of the assembly worker can be avoided.
 Furthermore, if a test window that directly leads to the stabilizer is
 opened in the front of the housing, when a test jig having a shape
 identical to that of the male terminal is inserted into the test window,
 the test jig will contact the stabilizer. Thus a continuity test, etc. can
 be carried out without causing any damage to the leaf spring, etc. As no
 reinforcing spring is used, the height of the female terminal is lower,
 and as the round part is in a position beyond the reach of the male
 terminal and it does not require any space for a male terminal to move
 into beneath the leaf spring, the height of the female terminal can be
 lowered further. Moreover, as the lance of the housing is flexed in the
 direction of width by the stabilizer having a face set in the direction of
 width, there is no need of providing a space for flexing in the direction
 of height of the housing and the height can be reduced. As a result, the
 connector can be made more compact in the direction of height as much as
 possible.
 When the female terminal for a connector according to the present invention
 is used, as the flexural rigidity of the leaf spring is increased by the
 bead, the single leaf spring can stably provide a sufficient contacting
 force, and the contacting part of the leaf spring can be shifted forward.
 As this reduces the length of insertion of the male terminal, the
 counterpart connector can made more compact. In addition to it, the
 tolerance to slant of the male terminal is increased and the yield of the
 connectors can be improved. Furthermore, as the radius of curvature of the
 round part can be increased in a position beyond the reach of the male
 terminal, generation of cracks, etc. in the leaf spring can be prevented
 to stabilize the contacting force. As the stabilizer is provided at the
 front end of the terminal body, inverse insertion of the female terminal
 can be prevented reliably. Moreover, the stabilizer can be used in
 conducting a continuity test or the like on the female terminal, and this
 prevents damage to the leaf spring, etc. Use of a single leaf spring,
 shifting of the round part backward and flexing of the lance in the
 direction of width allow to be made of the connector more compact in the
 direction of height as much as possible.

PREFERRED EMBODIMENTS OF THE INVENTION
 In the following, embodiments of the present invention will be described
 with reference to the attached drawings. FIG. 2 through FIG. 6 show a
 female terminal T of a connector C of the first embodiment. FIG. 1, FIG.
 10A and FIG. 10B show the connector C wherein this female terminal T is
 inserted in a housing H.
 As shown in FIG. 2 through FIG. 6, the female terminal T is provided with a
 terminal body 10 having an approximately tubular front half part that can
 be inserted into a chamber 51 of the housing H, a leaf spring 20 of which
 a root end is integral to the front half of the terminal body 10, and a
 stabilizer 30 being on the outer side of the terminal body 10. It should
 be noted that with regard to the female terminal T, the front-rear
 direction is the longitudinal direction. For example, in FIG. 4, it is the
 direction perpendicular to the paper. The direction of height
 substantially corresponds to the direction of flexing of the top end of
 the leaf spring 20; for example, in FIG. 3, it is the direction
 perpendicular to the paper. The direction of width substantially
 corresponds to the direction of width of the top end of the leaf spring
 20; for example, in FIG. 2, it is the direction perpendicular to the
 paper. This system of directions is also applied to the housing H. Hence
 the front-rear direction, the height direction and the width direction of
 the female terminal T that is inserted in the chamber 51 are the
 front-rear direction, the height direction and the width direction of the
 chamber 51 of the housing H, respectively.
 A port 11 is opened in the front end of the above-mentioned terminal body
 10 to receive a male terminal TT. A splicing part 12 for connecting an
 electric wire W is provided in the back thereof. This splicing part 12 is
 formed to have an approximately U-shaped section. Its upper edge portions
 are bent inward to crimp the conductor of the electric wire W. A
 longitudinally intermediate part of the terminal body 10 is provided with
 a fixing part 13 into which a retainer 60 of the housing H is to be
 fitted. This fixing part 13 is formed into an approximately U-shape when
 seen from the side. As the upper edges of the fixing part 13 are formed to
 be lower than the upper wall of the front half part of the terminal proper
 10, the retainer 60 can be fitted into the fixing part 13 as shown in FIG.
 1.
 As shown in FIG. 1, FIG. 5A, FIG. 5B and FIG. 8, the top end of the
 above-mentioned leaf spring 20 extends forward inside the front half part
 of the terminal body 10 and can be flexed in the height direction. When a
 male terminal TT is inserted, the top end of the leaf spring 20 will be
 pressed to contact the male terminal TT. At the root end of the leaf
 spring 20, a round part 21, that bends around an axis approximately
 parallel to the front half part into an approximately circular arc in a
 position beyond the reach of the male terminal TT, is formed. A bead 22
 that has a curved section to increase the flexural rigidity is formed
 ahead of the round part 21 of the leaf spring 20. Here bending around an
 axis approximately parallel to the front half part means bending in such a
 way that displacement takes place in the direction of height. The round
 part 21 is formed into an approximately circular arc around an axis that
 is in the front-rear direction of the terminal body 10. Examples of the
 sectional forms of the above-mentioned bead 22 include approximately
 U-shaped form, approximately W-shaped form and their inverted forms. What
 is important is that when the leaf spring 20 is sectioned along a plane in
 the front-rear direction the moment of inertia of area along a neutral
 axis passing sidewise in the middle, in the thickness direction, of the
 leaf spring 20 is greater than that of a flat plate. Slits 14, 14 are
 formed in a portion of terminal body 10 that is continuous to the round
 part 21 from both side edges of the round part's root end in the width
 direction of the terminal body 10. At the top end of the above-mentioned
 terminal body 10, when necessary, a guide 15 is formed to cover a gap
 between the top end of the leaf spring 20 and the inner wall of the
 terminal body 10. This guide 15 prevents inadvertent insertion of the male
 terminal TT or a screwdriver for inspection, etc. into the gap.
 As shown in FIG. 1, FIG. 10A and FIG. 10B, when the terminal body 10 is
 inserted into the chamber 51 of the housing H, the above-mentioned
 stabilizer 30 will fit into a groove 52 that is formed in the front-rear
 direction and moves forward beyond a lance 53 that is formed in the
 groove. The stabilizer 30 will reach a position in front of the lance 53
 and will be fixed there by the lance 53. The stabilizer 30 having a face
 in the width direction is erected in the height direction at the front end
 of the terminal body 10. In the present embodiment, the stabilizer 30 is
 provided on the upper side of the terminal proper 10.
 As shown in FIG. 1, FIG. 10A and FIG. 10B, the above-mentioned housing H
 comprises a housing body 50 in which through chambers 51 are formed in the
 front-rear direction and a retainer 60 that fits into the housing body 50
 and penetrates into the chambers 51. The above-mentioned housing proper 50
 is provided with grooves 52 that are made in the height direction from the
 chambers, extend in the front-rear direction and receive the stabilizers
 30, lances 53 that are formed in respective grooves to be flexed in the
 width direction of the chambers 51 and fix the stabilizers 30 by the front
 sides, and testing windows 54 that allow access to the grooves 52 in front
 of the lances 53 from the front side. The above-mentioned grooves 52 are
 formed upward from the chambers 51. In FIG. 10A and FIG. 10B, the
 exemplifying connector C has a single row of parallel chambers 51 arranged
 in the width direction. However, as shown in FIG. 12A, such rows of
 chambers 51 may be arranged in several columns in the height direction.
 The above-mentioned female terminal T is formed from a single piece or
 blank of sheet metal. As shown in FIG. 9, plural female terminals T, T . .
 . in a developed form, with a runner connecting them together, are blanked
 out of a sheet metal. Next, various parts are bent to form the female
 terminals T, T . . . into the final shape. After that, the respective
 female terminals T are separated from the runner N.
 In the above-mentioned first embodiment, after an electric wire W is
 connected to the splicing part 12 of the terminal body 10, when the female
 terminal T is inserted into a chamber 51 of the housing H, the stabilizer
 30 will fit into a groove 52 of the housing H (the state shown in FIG.
 10A), then the stabilizer 30 will go beyond a lance 53 of the housing H
 and will be fixed by the lance 53. This is the primary fixing of the
 female terminal T to the housing H (the state shown in FIG. 10B). Next,
 when the retainer 60 is forced into the housing H, the retainer 60 will
 fit into the fixing part 13 of the terminal body 10. This is the secondary
 fixing of the female terminal T to the housing H. When this connector C is
 opposed to a counterpart connector CC and its male terminals TT, TT . . .
 are inserted into the female terminals T, T . . . , each leaf spring 20
 will press to contact a male terminal TT to make mechanical connections
 and electric connections between both connectors C, CC (the state shown in
 FIG. 1).
 In that case, as the bead 22 is formed beyond the round part 21 of the leaf
 spring 20 on the top end side thereof, the flexural rigidity of the leaf
 spring 20 is greater and a sufficient contacting force is provided without
 provision of a reinforcing spring. Moreover, as no reinforcing spring is
 provided, the spring constant has no point of inflection, and the
 contacting force of each product is stabilized. Furthermore, as the
 flexural rigidity of the leaf spring 20 is greater, a sufficient
 contacting force is generated even if a contacting part of the leaf spring
 20 is shifted forward close to the port. As a result, the length of
 insertion of the male terminal TT is shortened, and in turn, the housing
 HH of the counterpart connector CC that contains the male terminal TT is
 shortened and made more compact and the tolerance to slant of the male
 terminal TT is also increased. This reduces troubles that a male terminal
 TT cannot be inserted into a female terminal T. Thus the yield of
 connectors CC can be improved. Moreover, as the round part 21 is formed in
 a position beyond the reach of the male terminal TT, the radius of
 curvature of the round part 21 can be set larger by extensively using the
 interior of the front half part of the terminal body in the height
 direction. This prevents generation of cracks in the round part 21 and
 stabilizes the contacting force. As the stabilizer 30 is provided at the
 top end of the terminal body 10, if the female terminal T is inserted into
 a chamber 51 of the housing H in a wrong orientation, the stabilizer 30
 will catch on the entrance of the chamber 51 in the initial stage of
 insertion. Thus inverse insertion of the female terminal T is prevented
 reliably, and any damage to the housing H due to incorrect operation of
 the worker assembly be avoided. Furthermore, as the test window 54 that
 directly leads to the stabilizer 30 is opened in the front of the housing
 H, when a test jig having a shape identical to that of the male terminal
 TT is inserted into the test window 54, the test jig will contact the
 stabilizer 30. Thus a continuity test, etc. can be carried out without
 giving any damage to the leaf spring, etc. As no reinforcing spring is
 used, the height of the female terminal T is lowered, and as the round
 part 21 is in a position beyond the reach of the male terminal TT and it
 does not require any space for the male terminal TT to move into beneath
 the leaf spring 20, the height of the female terminal T can be lowered
 further. Moreover, as the lance 53 of the housing H is flexed in the
 direction of width by the stabilizer 30 having a face set in the direction
 of width, there is no need of providing a space for flexing in the
 direction of height of the housing and the height can be reduced. As a
 result, the connector C can be made more compact in the direction of
 height as much as possible. In particular, in the connector C wherein
 chambers 51 are arranged in the direction of height, several female
 terminals T are arranged in succession in the direction of height, and the
 number of walls between chambers 51 is larger. When the height of each
 female terminal T is lowered and the walls between chambers 51 are made
 thinner, the connector C can be made more compact significantly in the
 direction of height. Because of this, the connector C is suitable as a
 connector for automobiles in which higher space utility is rigorously
 demanded. When the stabilizer 30 is provided on the lower side of the
 terminal body 10, the groove 52 is made downward from the chamber 51 and
 the lance 53 is provided to flex in the direction of width of the chamber
 51, the connector C can be made more compact in the direction of height
 just like the above-mentioned embodiment.
 When the female terminal T is to be blanked out of a sheet metal, it is
 necessary to make sure that the respective parts do not interfere with
 each other in the developed form. These restraints may impair the degree
 of freedom of design. However, when the round part 21 is bent into an
 approximately circular arc around an axis that is in the front-rear
 direction of the terminal body 10 as is the case of the above- mentioned
 first embodiment, as shown in FIG. 9, if the female terminal T is formed
 from a single sheet metal, the leaf spring 20 and the splicing part 12 in
 the developed form of the female terminal T hardly interfere with each
 other. Thus the degree of freedom of design is enhanced.
 Connectors of this kind may undergo wear caused by microsliding. When a
 pair of connectors being connected with each other are subjected to
 temperature changes, they will undergo thermal deformation. As a result,
 the contacting surfaces of the female terminal and the male terminal slip
 relative to each other. When this is repeated, oxide films that are formed
 near the contacting surfaces will peel eventually. This is microsliding
 wear. Accumulation of this oxide film eventually causes imperfect contact.
 To prevent this, one way is to increase the contacting force of the leaf
 spring so that the slip hardly occurs. This, however, demands a large
 force in connecting the connectors together. It will be hard to use
 connectors having a large number of terminals. However, as is the case in
 the above-mentioned first embodiment, when slits 14, 14 are formed in a
 portion of terminal body 10 that is continuous to the round part 21 from
 both side edges of the round part's root end in the direction crossing the
 front-rear direction, the round part 21 shifts a little in the front-rear
 direction due to a deformation of the portion of the terminal body between
 slits 14, 14. This shift absorbs thermal deformation due to temperature
 changes which otherwise would cause the contacting faces of the leaf
 spring 20 and the male terminal TT to slip relative to each other. Thus
 the microsliding wear hardly occurs. Accordingly, imperfect contact due to
 oxide films hardly occurs. This means a high durability in, for example,
 an area of harsh temperature changes. In this case, as there is no need of
 microsliding wear preventive measures, such as increasing the contacting
 force of the leaf spring 20 by, for example, changing the radius of
 curvature of the round part 21, the force required for connecting the
 connector C can be set adequately and workability can be enhanced.
 Moreover, a connector C with a large number of terminals can be set.
 Next, a second embodiment will be described with reference to FIG. 11. This
 second embodiment differs from the above- mentioned first embodiment only
 in the configuration of the round part of the leaf spring, and other
 configurations are identical. Accordingly, identical reference characters
 are given to members that exhibit identical functions of the members of
 the first embodiment. The description of the first embodiment except a
 portion concerning the configuration of the round part of the leaf spring
 is applicable here in its entirety as the description of the configuration
 of the second embodiment.
 The configuration of the round part of the leaf spring of the second
 embodiment will be described. As shown in FIG. 11, the round part 21 of
 the second embodiment is formed by bending a portion into an approximately
 circular arc around an axis that is in the right-left direction of the
 terminal body 10, and slits 14, 14 are not formed.
 In this second embodiment, as the round part 21 is bent into an
 approximately circular arc around an axis that is in the right- left
 direction, it is necessary to some extent to consider interference between
 the leaf spring 20 and the splicing part 12 in the developed form of the
 female terminal T. Moreover, as slits 14, 14 are not formed,
 microsliding-wear-preventive effects of the slits are not available.
 However, other operations and actions of the second embodiment are similar
 to those of the first embodiment. Hence the descriptions concerning them
 applicable here in their entirety as the descriptions of the operations
 and actions of the second embodiment.
 The present invention includes an embodiment that is the first embodiment
 except no slits are formed and an embodiment that is the second embodiment
 with formation of slits. In the first embodiment, the round part 21 is
 formed by bending into an approximately circular arc around an axis that
 is in the front-rear direction of the terminal body 10, and in the second
 embodiment, the round part 21 is formed by bending into an approximately
 circular arc around an axis that is in the left-right direction of the
 terminal body 10, but the present invention includes all embodiments
 having a round part that bends around an axis approximately parallel to
 the front half part into an approximately circular arc in a position
 beyond the reach of any male terminal.