An electrical connector

Abstract: [Object] To ensure a reliable locking function by a resin locking portion even when the resin locking portion is thinned. [Solution] Since a wedge-shaped biting portion 13B at the leading end of a resin locking portion 13 comes into contact with and bites into a recess-shaped corner portion 35 formed by an outer surface 27 of the terminal fitting 20 and a locking surface 32, the leading end of the resin locking portion 13 is pushed from a projecting end toward a base end (toward the outer surface of the terminal fitting 20) of the locking surface 32 if a force acts on the terminal fitting 20 in a withdrawing direction. Thus, even if the resin locking portion 13 is thinned to reduce its resilient rigidity, there is no possibility of the resin locking portion 13 being disengaged from the locking surface 32, providing highly reliable locking.

Description: The present invention relates to a connector in which a terminal fitting is locked by a locking portion. A known connector in which a terminal fitting is inserted into a cavity of a connector housing and locked by a cantilever-shaped resin locking portion formed along an inner wall of the cavity is constructed such that a locking projection is formed by embossing a wall portion of a box portion of the terminal fitting in the form of a rectangular tube and the leading end of the resin locking portion is engaged with the locking projection obliquely from behind. The resin locking portion engaged with the locking projection can keep locking by its resilient rigidity and, therefore, the terminal fitting can be held locked. The connectors in which the terminal fitting is locked by the resin locking portion are disclosed, for example, in Japanese Unexamined Patent Publication No. 2000-294334. In the case of making such a connector smaller, the thickness of the resin locking portion (dimension in the same direction as the projecting direction of the locking projection) is also set smaller. However, if the resin locking portion is thinned, the resilient rigidity of the resin locking portion, i.e. reliability of a locking function by the resin locking portion is reduced. In other words, if an excessive withdrawing force acts on the terminal fitting, the resin locking portion may be resiliently deformed and its leading end engaged with the locking projection may be deformed in such a direction away from the locking projection. US-A-3 781 760, which forms the preamble of the independent claim, discloses a terminal connector block having snap latches for retaining terminals in insulated cavities, the snap latch having a nose including a rearwardly sloped latching face partially in the patch of withdrawal of the terminal from the cavity and a terminal stop or recess located between the withdrawal compression point of the latch and the outer surface thereof. Upon application of a withdrawal force on the terminal, the terminal engages the sloping face, bends the latch into the cavity and slides along the face to the stop. The object of the present invention is to ensure reliability of a locking function by a locking portion even if the locking portion is thinned. This object is solved according to the invention by a connector according to claim 1. Preferred embodiments of the invention are subject of the dependent claims. According to the invention, there is provided a connector in which at least one cavity is formed in a connector housing preferably formed of a synthetic resin, a resiliently deformable locking portion cantilevers along an inner wall of the cavity, and at least one terminal fitting having a locking surface projecting from its outer surface at an angle different from 0° or 180°, preferably substantially at right angles is or can be at least partly insertable into the cavity and locked therein by engaging the leading end of the locking portion with the locking surface, wherein said outer surface is substantially parallel to an insertion direction (ID) of the terminal fitting, wherein the leading end of the locking portion is formed with a wedge-shaped biting portion which comes into contact with and bites into or interacts with or engages a recess-shaped corner portion formed by an outer surface of the terminal fitting and the locking surface, in particular when the terminal fitting is moved in a direction of withdrawing from the cavity. Since the wedge-shaped biting portion at the leading end of the locking portion comes into contact with and bite into the recess-shaped corner portion formed by the outer surface of the terminal fitting and the locking surface, the leading end of the locking portion is pushed from the projecting end toward the base end (toward the outer surface of the terminal fitting) of the locking surface if a force acts on the terminal fitting in a withdrawing direction. Thus, even if the locking portion is thinned to reduce its resilient rigidity, there is no possibility of the locking portion being disengaged from the locking surface, providing highly reliable locking. According to a preferred embodiment of the invention, the connector housing is formed of a synthetic resin, and the locking portion is formed as a resiliently deformable resin locking portion which unitarily cantilevers along an inner wall of the cavity. Preferably, a surface of the biting portion opposed to the locking surface is so slanted as to approach the locking surface as it extends from its projecting end toward its base end. Since the surface of the biting portion opposed to the locking surface is slanted, the (resin) locking portion is pushed toward the base end of the locking surface, i.e. toward the outer surface of the terminal fitting by the inclination of this slanted surface when a force acts on the terminal fitting in the withdrawing direction. Further preferably, the base end of the locking surface is obliquely cut to form a wedge-shaped recess corresponding to the biting portion between the obliquely cut surface and the outer surface of the terminal fitting. By fitting the biting portion into the recess, a displacement of the biting portion with respect to the locking surface is more securely restricted. Still further preferably, the wedge-shaped recess is inclined such that a displacement of the locking portion is prevented. Further preferably, the terminal fitting comprises a locking surface wall on which the locking surface is provided and a reinforcing wall provided on an inner part thereof substantially in contact with the locking surface wall. Still further preferably, the locking surface wall comprises a notch, preferably extending over substantially the entire width of the locking surface wall so as to at least partly expose the reinforcing all. Most preferably, a length of an engaging surface is the sum of a projecting distance of the locking surface and a thickness of the locking surface wall. According to a further preferred embodiment of the invention, the terminal fitting is formed with a beveled portion having a slanted surface extending in a direction oblique to a terminal insertion direction. Preferably, an angle of inclination of the slanted surface to the terminal inserting direction is set smaller than an angle of inclination which is formed between the terminal insertion direction and a trace of displacement of an extending end of the locking portion during its resilient restoration. These and other objects, features and advantages of the present invention will become more apparent upon reading of the following detailed description of preferred embodiments and accompanying drawings. It should be understood that even though embodiments are separately described, single features thereof may be combined to additional embodiments. FIG. 1 is a section of one embodiment of the invention, FIG. 2 is a side view of a terminal fitting, FIG. 3 is a partial longitudinal section of the terminal fitting, FIG. 4 is a lateral section of the terminal fitting, FIG. 5 is a bottom view of the terminal fitting, FIG. 6 is a partial enlarged longitudinal section showing a state where a resin locking portion is in contact with a slanted surface of a locking projection, FIG. 7 is a partial enlarged longitudinal section showing a state where the resin locking portion is engaged with the locking projection to lock the terminal fitting, FIG. 8 is a partial enlarged longitudinal section showing a state where the resin locking portion is disengaged from the locking projection to resiliently restore, and FIG. 9 is a partial enlarged longitudinal section showing a resiliently restoring state of the resin locking portion when the locking projection is formed with no beveled portion. Hereinafter, one preferred embodiment of the present invention is described with reference to FIGS. 1 to 9. A connector of this embodiment is comprised of a connector housing 10 and terminal fittings 20. In the following description, reference is made to FIG. 1 concerning forward and backward directions and vertical direction, i.e. left side in FIG. 1 is referred to as front side and vertical direction is based on FIG. 1. The connector is preferably of the micro-connector type in which the terminal fittings 20 have a width equal to or smaller than about 0.64 mm. The connector housing 10 is formed e.g. of a synthetic resin material and cavities 11 long in forward and backward directions penetrate the connector housing 10. The terminal fittings 20 are at least partly inserted into the cavities 11 through terminal insertion openings 12 preferably at their rear ends. In each cavity 11 is formed a locking portion 13, preferably a resin locking portion 13 which cantilevers preferably in a forward direction which is the same direction as an inserting direction ID of the terminal fitting 20 (hereinafter, terminal inserting direction ID) substantially along a bottom wall 26. The resin locking portion 13 extends obliquely upward from a supporting point 14 at its rear end toward the front and is resiliently or elastically deformable downward (direction away from the terminal fitting 20 or the cavity 11) about the supporting point 14. When the resin locking portion 13 is resiliently restored upward (direction in which the terminal fitting 20 is locked or toward the cavity 11), an extending end thereof is displaced in such a manner as to draw a trace or path not in a direction normal to the terminal inserting direction ID, but in a direction DD oblique (i.e. arranged at an angle different from 0°. 90° or 180°) to the terminal inserting direction ID (FIG. 8). The front end (extending or distal end) of the resin locking portion 13 serves as a biting portion 13B. A front end surface 13C (surface opposed to a locking surface 32 of the terminal fitting 20 to be described later in forward and backward or longitudinal directions) of the resin locking portion 13 forming this biting portion 13B is so slanted as to approach the locking surface 32 as it extends from its projecting end (bottom end) to its base end (upper end). Preferably, the locking surface 32 is inclined at an angle comprised between about 60° and 120°, more preferably between about 70° and 110° most preferably between about 80° and 100° with respect to the terminal insertion direction ID or the outer surface 27 of the terminal fitting 20. The locking surface 32 is slanted in a direction not normal, but oblique to the terminal inserting direction ID. An upper surface 13D (surface opposed or facing to the bottom surface of the terminal fitting 20) of the resin locking portion 13 likewise forming the biting portion 13B is substantially parallel with the terminal inserting direction ID. Accordingly, the front end surface 13C and the upper surface 13D of the resin locking portion 13 form an acute angle when viewed sideways, and the biting portion 13B is substantially wedge-shaped by setting this angle in such a manner. The terminal fitting 20 is constructed such that a box portion 21 in the form of a substantially rectangular tube is formed at a substantially front half thereof and a wire crimping portion 22 is formed at a substantially rear half thereof. The box portion 21 is formed such that a pair of side walls 24, 25 extend downward from the left and right or lateral side edges of an upper wall 23, a bottom wall 26 substantially horizontally extends from the bottom edge of one side wall 24, and a reinforcing wall 27 (as a preferred outer surface of the terminal fitting 20) substantially horizontally extends from the bottom edge of the other side wall 25 to be placed on the inner surface (upper surface in FIG. 4) of the bottom wall 26. A substantially middle portion of the bottom wall 26 with respect to forward and backward direction is cut away, thereby forming a notch or recess 28. The notch 28 preferably extends over the substantially entire width of the bottom wall 26 as shown in FIG. 5 and, accordingly, the reinforcing wall 27 is exposed at the notch 28. A cut surface 29 at the front side of the notch 28 extends straight in transverse direction, i.e. direction substantially normal to the terminal inserting direction ID. Further, a front part of the bottom wall 26 is embossed preferably at a widthwise center substantially over its rear half, thereby forming a locking projection 30 to protrude downward (outward). The locking projection 30 has a ridge 31 which is substantially continuous with the bottom wall 26 and extends backward from the bottom wall 26 and whose projecting distance increases toward the back. Accordingly, the locking projection 30 is so slanted or inclined with respect to the terminal insertion direction ID as to allow an easier deflection of the locking projection 13 when the terminal fitting 20 is inserted into the respective cavity 11. The locking surface 32 at the rear end of the locking projection 30 is substantially in flush with and continuous with the cut surface 29 at the front side of the notch 28, and projects from the lower surface of the reinforcing wall 27 in a direction at an angle different from 0° or 180°, preferably substantially normal to the terminal inserting direction ID. At a projecting end (bottom end in FIG. 4) of the locking projection 30 is formed a beveled portion 33 having a slanted surface 34 extending in a direction oblique to the terminal inserting direction ID. The inclination of the slanted surface 34 is reverse of that of the ridge 31 with respect to forward and backward or longitudinal directions. The slanted surface 34 is slanted in such a direction as to approach the bottom wall 26 toward the rear end. As shown in FIG. 8, an angle of inclination α of the slanted surface 34 to the terminal inserting direction ID is set smaller than an angle of inclination β which is formed between the terminal insertion direction ID and a trace or path of displacement of the extending end 13A of the resin locking portion 13 during its resilient restoration (precisely during restoring displacement of the extending or distal end 13A of the resin locking portion 13 from a position where it is engaged with the locking projection 30 to a free state where it can lock the terminal fitting 20). Further, the extending end 13A (biting portion 13B) of the resin locking portion 13 obliquely comes into contact from behind (i.e. a direction corresponding to the terminal insertion direction ID) with a corner portion 35 which is a preferably right-angled recess between the reinforcing wall 27 of the box portion 21 and the locking surface 32 of the locking projection 30 when viewed sideways as if it would bite in. The terminal fitting 20 properly inserted into the cavity 11 can be held locked by this biting (locking function) of the resin locking portion 13 into the locking projection 30. At such a corner portion 35, a key- or spline- or wedge-shaped recess 37 corresponding to the biting portion 13B is formed between a slanted cut surface 36 and the outer surface (lower surface) of the reinforcing wall 27 by obliquely cutting the base end (upper end) of the locking surface 32 of the locking projection 30 and the cut surface 29 continuous therewith. Next, how this embodiment acts is described. During insertion of the terminal fitting 20 into the connector housing 10, a projecting end 30A (lowest rear end of the ridge 31 ) of the locking projection 30 of the terminal fitting 20 comes into contact with the upper surface 13D of the resin locking portion 13 held in its free state and resiliently deform the resin locking portion 13 downward while being held in sliding contact with the upper surface 13D. At this stage, the extending end 13A of the resin locking portion 13 is displaced obliquely forward to the bottom (direction oblique to the terminal inserting direction ID). Immediately before the terminal fitting 20 reaches its proper insertion position, the projecting end 30A (rear end of the ridge 31 ) of the locking projection 30 passes the extending end 13A of the resin locking portion 13, and the extending end 13A starts moving in sliding contact with the slanted surface 34. During this time, the resin locking portion 13 is slightly restored to displace upward or towards the reinforcing wall 27 by its resilient or elastic restoring force. When the terminal fitting 20 reaches its proper insertion position, the extending end 13A of the resin locking portion 13 reaches the rear end of the slanted surface 34 as indicated by solid line in FIG. 8, thereby being disengaged from the slanted surface 34. The extending end 13A disengaged from the slanted surface 34 is restored to displace obliquely upward to the back (direction oblique to the terminal inserting direction ID) by the resilient restoring force of the resin locking portion 13, returning to its free state shown in chained line in FIG. 8. At this time, the extending end 13A is displaced backward from the locking projection 30 by a distance Sa. In this state, since the front end surface 13C of the resin locking portion 13 is opposed to the locking surface 32 of the locking projection 30 and the cut surface 29 from behind (as seen in the terminal insertion direction ID), even if the terminal fitting 20 is displaced backward, any further backward displacement of the terminal fitting 20 is restricted by the engagement of the locking surface 32 and the cut surface 29 with the resin locking portion 13. As a result, the terminal fitting 20 is held locked. Further, if the terminal fitting 20 is displaced backward, the wedge-shaped biting portion 13B of the resin locking portion 13 bites into the wedge-shaped recess 37 of the corner portion 35, with the result that a downward (direction away from the locking projection 30) resilient displacement of the resin locking portion 13 is also restricted. As described above, in this embodiment, the notch 28 is formed in the bottom wall 26 of the terminal fitting 20, and part of the cut surface 29 of the notch 28 is so formed as to be substantially in flush with and continuous with the locking surface 32 of the locking projection 30. Thus, as shown in FIGS. 4 and 7, an engaging distance L of the terminal fitting 20 and the resin locking portion 13 can be ensured, which distance is a sum of a projecting distance La of the locking surface 32 from the bottom wall 26 and a thickness Lb of the bottom wall 26. Therefore, locking reliability is higher as compared to a case where the engaging distance is comprised only of the projecting distance La of the locking projection 30. Further, since the reinforcing wall 27 is placed on the inner surface of the bottom wall 26 in the box portion 21 of the terminal fitting 20 and, accordingly, free from reduction in strength, the notch 28 can be formed over the entire width of the bottom wall 26. This ensures a large engaging distance or width of the terminal fitting 20 and the resin locking portion 13 in widthwise direction, bettering the reliability of the locking function. Furthermore, since the wedge-shaped biting portion 13B at the leading end of the resin locking portion 13 comes into contact with and bite into the recess-shaped corner portion 35 formed by the reinforcing wall 27 of the terminal fitting 20 and the locking surface 32 of the locking projection 30, the leading end of the resin locking portion 13 is pushed from the projecting end toward the base end (toward the reinforcing wall 27) of the locking surface 32 if a force acts on the terminal fitting 20 in a withdrawing direction. Thus, even if the resin locking portion 13 is thinned to reduce its resilient rigidity, there is no possibility of the resin locking portion 13 being disengaged from the locking surface, providing highly reliable locking. Further, since the corner portion 35 is provided with the wedge-shaped recess 37 and the biting portion 13B is engaged with the recess 37, a displacement of the biting portion 13B with respect to the locking surface 32 or the cavity 11 is more securely restricted. Since the front end surface 13A of the biting portion 13B opposed to the locking surface 32 is slanted, the resin locking portion 13 is pushed toward the base end of the locking surface 32, i.e. toward the terminal fitting 20 by the inclination of this slanted surface when a force acts on the terminal fitting 20 in the withdrawing direction (direction contrary to the insertion direction ID). This also contributes to an improvement in locking reliability. Further, since the slanted beveled portion 33 is formed on the projecting end of the locking projection 30, a clearance Sa extending in forward and backward directions and necessary for the extending end 13A of the resin locking portion 13 to be disengaged from the locking projection 30 and resiliently restored, i.e. the clearance Sa between the locking projection 30 and the resin locking portion 13 which causes shaking, etc. (see FIG. 8) can be smaller as compared to a clearance Sb in the case that a locking projection 130 is formed with no beveled portion 33 (see FIG. 9). Furthermore, since the beveled portion 33 is not cut by a surface parallel with the terminal inserting direction ID, but has the slanted surface 34 extending in the direction oblique to the terminal inserting direction ID, the slanted surface 34 also functions as a locking portion with the resin locking portion 13 similar to the locking surface 32 and the cut surface 29 if the terminal fitting 20 is strongly pulled in the withdrawing direction to cause the locking projection 30 to bite into (or interact with or engage) the front end surface 13C of the resin locking portion 13. Accordingly, a large engaging distance of the locking projection 30 and the resin locking portion 13 can be ensured as compared to a case where the projecting distance of the locking projection is simply made smaller by cutting the beveled portion along a surface parallel with the terminal inserting direction. Further, the angle of inclination α of the slanted surface 34 to the terminal inserting direction is set smaller than the angle of inclination β which is formed between the terminal insertion direction and the trace or path of displacement of the extending end 13A of the resin locking portion 13 during its resilient restoration, and the extending end 13A of the resin locking portion 13 moves in sliding contact with the slanted surface 34 during the resilient restoration. Since a pushing force acts in the terminal inserting direction ID from the resin locking portion 13 on the terminal fitting 20 by the resilient restoring force of the resin locking portion 13 and the angle of inclination of the slanted surface 34 while the extending end 13A is in sliding contact, this prevents the terminal fitting 20 from being left insufficiently inserted. The present invention is not limited to the above described and illustrated embodiment. For example, following embodiments are also embraced by the technical scope of the present invention as defined in the claims. Beside the following embodiments, various changes can be made without departing from the scope of the present invention as defined in the claims. (1 ) Although the wedge-shaped recess 37 is formed between the slanted cut surface 36 and the outer surface 27 of the terminal fitting 20 by obliquely cutting the base end of the locking surface 32 in the foregoing embodiment, no such recess may be formed according to the present invention. (2) Although the locking surface 32 extends in the direction substantially normal to the terminal inserting direction ID in the foregoing embodiment, it may extend in a direction oblique (i.e. at an angle different from 0°, 90° or 180°) to the terminal inserting direction ID according to the present invention. (3) Although the wall portion of the box portion in the form of a rectangular tube is used to form the locking projection in the foregoing embodiment, the present invention is also applicable to a case where the locking projection is formed on an other wall portion not belonging to the box portion and a case where the terminal fitting is formed with no box portion. (4) Although the terminal fitting 20 is described as a female terminal fitting in the foregoing embodiment, the present invention is also applicable to a case where the terminal fitting is a male terminal fitting. LIST OF REFERENCE NUMERALS 10 connector housing 11 cavity 13 resin locking portion 13B biting portion 13C front end surface (surface opposed to a locking surface) of the resin locking portion 20 terminal fitting 27 reinforcing wall (outer surface of the terminal fitting) 32 locking surface 35 corner portion 36 slanted cut surface 37 wedge-shaped recess

Claims: A connector in which at least one cavity (11 ) is formed in a connector housing (10), a resiliently deformable locking portion (13) cantilevers along an inner wall of the cavity (11 ), and at least one terminal fitting (20) is at least partly insertable into the cavity (11 ), characterized in that said terminal fitting (20) has a locking surface (32) projecting from its outer surface (27) at an angle different from 0° or 180°, preferably substantially at right angles, said outer surface (27) being substantially parallel to an insertion direction (ID) of the terminal fitting (20), and the terminal fitting (20) is locked in the cavity (11) by engaging the leading end (13A) of the locking portion (13) with the locking surface (32), wherein the leading end (13A) of the locking portion (13) is formed with a wedge-shaped biting portion (13B) which can come into contact with and bite into a recess-shaped corner portion (35) formed by an outer surface (27) of the terminal fitting (20) and the locking surface (32). A connector according to claim 1, wherein the connector housing (10) is formed of a synthetic resin, and the locking portion (3) is formed as a resiliently deformable resin locking portion (13) which unitarily cantilevers along an inner wall of the cavity (11 ). A connector according to one or more of the preceding claims, wherein a surface (13C) of the biting portion (13B) opposed to the locking surface (32) is so slanted as to approach the locking surface (32) as it extends from its projecting end toward its base end. A connector according to one or more of the preceding claims, wherein the base end of the locking surface (32) is obliquely cut to form a wedge-shaped recess (37) corresponding to the biting portion (13B) between the obliquely cut surface and the outer surface (27) of the terminal fitting (20). A connector according to claim 4, wherein the wedge-shaped recess (37) is inclined such that a displacement of the locking portion (13) is prevented. A connector according to one or more of the preceding claims, wherein the terminal fitting (20) comprises a locking surface wall (26) on which the locking surface (32) is provided and a reinforcing wall (27) provided on an inner part thereof substantially in contact with the locking surface wall (26). A connector according to claim 6, wherein the locking surface wall (26) comprises a notch (28), preferably extending over substantially the entire width (FIG. 5) of the locking surface wall (26) so as to at least partly expose the reinforcing wall (27). A connector according to claim 7, wherein a length (L) of an engaging surface is a sum of a projecting distance (La) of the locking surface (32) and a thickness (Lb) of the locking surface wall (26). A connector according to one or more of the preceding claims, wherein the terminal fitting (20) is formed with a beveled portion (33) having a slanted surface (34) extending in a direction oblique to a terminal insertion direction (ID). A connector according to claim 9, wherein an angle of inclination (α) of the slanted surface (34) to the terminal inserting direction (ID) is set smaller than an angle of inclination (β) which is formed between the terminal insertion direction (ID) and a trace of displacement of an extending end (13A) of the locking portion (13) during its resilient restoration.

Inventors: TABATA MASAAKI, TANAKA TSUTOMU, TABATA, MASAAKI, TANAKA, TSUTOMU, Tabata, Masaaki, c/o Sumitomo Wiring Systems, Ltd, Tanaka, Tsutomu, c/o Sumitomo Wiring Systems, Ltd
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 2001
Main classification: H01R13
IPC codes: H01R13