Connector

Abstract

Connector (11) comprising: a flexible engagement part (25) having a base end which is supported in a cantilever-like manner in a connection receiving chamber (17) for receiving a connecting piece (19) and which can thus be elastically deformed, and which has a free end (27) with which the connecting piece (19) to be inserted into the connection receiving chamber (17) is engaged, wherein the flexible engagement part (25), at the free end (37) of which a nose (31) is formed with which the connecting piece (19) engages, has the form of an inclined surface (29) in which a height of an upper section gradually increases from the free end (27) to the base end, so that a maximum shear area is created by a shear force of the connecting piece (19), characterized in that the inclined surface (29) has an angle of inclination (θ) along a course of a shear fracture in the nose (31).

Description

Technical FieldThe present invention relates to a connector in which a cantilever-shaped flexible engaging member is provided in a terminal accommodating chamber, and a terminal to be inserted into the terminal accommodating chamber is engaged with a free end thereof.Background ArtIn a connector in which a flexible engaging member is engaged with a terminal fitting and thereby held in a terminal accommodating chamber, rigidity of the flexible engaging member decreases due to a decrease in size. For this reason, there is a fear that the reliability in preventing the terminal from slipping off is deteriorated. For example, Patent Document 1 discloses a connector that attempts to solve the problem. In a connector shown in Figs. 7(a) and 7(b), a front end side of a flexible engaging member (also referred to as a "tongue") 501 is composed of a constant width portion 503 whose width is small and a remaining portion configured as a tapered portion 505 whose width gradually increases toward a base end. A reinforcing strip 507 is formed at a central portion in a transverse direction over a lower surface of the tongue 501, i.e., a surface opposed to a bending space.The reinforcing strip 507 has almost the same width as the portion 503 of the tongue 501 with the same width, and a front end is located at a position slightly offset rearward from a position of the front end of the tapered portion 505 of the tongue 501, and is provided with an extension rearward from the tongue 501 over an outer surface of a wall 511 of a lower surface of a cavity 509 constituting a terminal accommodation chamber. A side of the base end which is a bending support point of the tongue 501 is wide, and the reinforcing strip 507 may also be wide. High rigidity can thereby be achieved. Thus, it is possible to obtain a strong elastic force, thereby improving the reliability in preventing the terminal from slipping off. Further, there is a great deal of play for varying the width of the reinforcing strip 507, so that the rigidity of the tongue 501 can be regulated within an extended range.Prior Art DocumentPatent DocumentPatent Document 1: JP 2007-220 354 AProblems to be Solved by the InventionA problem that has occurred in connectors in recent years is that a terminal holding force of a flexible engagement part decreases as a size of the connector decreases. As the size of a tongue decreases, this also results in the decrease of the holding force. For this reason, it is an object to conform the reduction in size and the maintenance of the holding force to each other. In the conventional connector, the reinforcing strip 507 is provided to improve the holding force despite the reduction of the holding force of the tongue caused by the reduction of the size. However, it is not possible to prevent shear fracture of the terminal engagement portion (a nose) of the tongue caused by the reduction in size. The shear fracture in this case spreads obliquely toward an upper surface of the nose at a predetermined angle from a contact point of a front contact surface of the terminal. However, when only a height of the front contact surface of the terminal is increased to substantially increase a shear breaking length and thus improve a shear breaking strength, a male tab of the mating terminal and an upper surface of the tab of the tab are likely to interfere with each other, so that good terminal engagement is not possible. Moreover, in releasing the terminal, a degree of sticking of the tab with respect to a terminal engagement hole is too large as the height of the front contact surface of the terminal is increased. This leads to a problem that a releasing operation is made difficult. If the height of the entire nose of the tongue is increased to improve the shear rupture strength, an engaged condition or disengagement is adversely affected thereby. Furthermore, more material is unnecessarily consumed, whereby the environmental impact also increases and the improvement therefore remains ineffective.Further prior art is known from the documents JP H09-35 799 A and U.S. Pat. No. 6,126,484 A.The invention has been made in view of this situation, and an object is to provide a connector with which a shear strength can be effectively improved and a holding force can be strengthened despite a reduction in a tongue holding force caused by a reduction in size.Means for Solving the ProblemThe object of the invention can be achieved with the structure described below.(1) A connector includes a flexible engaging member having a base end supported in a terminal receiving chamber in a cantilever manner for receiving a terminal fitting and capable of being elastically deformed, and having a free end with which the terminal fitting to be inserted into the terminal receiving chamber is engaged, wherein the flexible engaging member having a nose formed at the free end thereof with which the terminal fitting is engaged has a shape of an inclined surface in which a height of an upper portion gradually increases from the free end toward the base end so that a maximum shearing area is formed by a shearing force of the terminal fitting.In the connector having the structure described in (1), an upper surface of the tab to be engaged with a terminal engagement hole is formed by the inclined surface whose height gradually increases toward the base end. The thickness of the upper portion of the nose increases. Thereby, it is possible to improve a shear strength against shear fracture. Further, the height of a front contact surface of the terminal does not increase. As a result, disturbing contact with a plug tab of the mating terminal can be reduced. Further, a degree of the catch of the tab with respect to the terminal engagement hole is prevented from becoming too large. This can prevent a release operation from being impaired. Further, the material usage does not increase unnecessarily as the height of the front contact surface of the terminal increases. Thus, it is possible to effectively improve a shearing force and thus to enhance a holding force despite a reduction in tongue holding force caused by a reduction in size.In the connector, the inclined surface has an inclination angle along a course of shear fracture in the nose.In the connector having the described structure, the inclined surface, which is the upper surface of the nose, is formed at the inclination angle along the course of shear fracture in the nose. Therefore, when shear fracture occurs, a direction of propagation of the fracture almost coincides with the longest direction of the shape of the nose. That is, it is possible to improve shear fracture strength by increasing a minimum volume of the nose, thus preventing unnecessary increase in material usage.Brief Description of the Drawings FIG. 1 is a sectional view showing a main part of a connector according to an embodiment of the invention. FIG. 2 is a perspective view showing an external appearance of the connector illustrated in FIG. 1. FIG. 3 is a front view of FIG. 2. FIG. 4 is a view taken along an arrow A-A in FIG. 3. FIG. 5 is a sectional view showing a terminal accommodating chamber having a terminal inserted therein. FIG. 6 is a sectional view illustrating the vicinity of a nose and showing a course of shear fracture. FIG. 7( a) is a plan view showing a conventional connector; and FIG. 7( b) is an enlarged view showing a principal part of a circled portion.BEST MODE FOR CARRYING OUT THE INVENTIONAn embodiment according to the invention will be described below with reference to the drawings.In a connector 11 according to the embodiment, a plurality of terminal insertion openings 15 for receiving a male terminal of a mating connector, which is not illustrated, are provided on an end surface in a longitudinal direction of a connector housing 13 formed in a shape of a rectangular parallelepiped. The terminal insertion ports 15 communicate with a plurality of terminal accommodation chambers 17 each formed by division in the connector housing 13. In the present specification, in order to simplify the description, the terminal insertion opening 15 of the connector 16 is referred to as a front part, and an opposite side thereof is referred to as a rear part. FIG. 3 is a front view of FIG. 2, FIG. 4 is a view seen in a direction of arrow A-A in FIG. 3, and FIG. 5 is a sectional view showing the terminal accommodating chamber 17 with a terminal 19 inserted therein.The terminal accommodation chamber 17 and the terminal accommodation chamber 17 on an underlying stage are separated from each other via a bottom wall 21. The female terminal 19 is inserted into the terminal receiving chamber 17 via a terminal mounting hole 23 formed in a rear portion of the connector housing 13. The receiving connection piece 19 serves only for illustrative purposes and can also be an insertion part. A flexible engaging member 25 protrudes into a space into which the terminal 19 is to be inserted. The flexible engaging member 25 is formed integrally with the connector housing 13 via a resin material. The flexible engaging member 25 having a base end connected to the bottom wall 21 includes a front end serving as a free end 27. The base end of the flexible engaging member 25 is cantilever-supported via the bottom wall 21 and thus can be elastically deformed. A crush space 17a is formed between the flexible engaging part 25 and the bottom wall 21 below the flexible engaging part 25.On the flexible engaging member 25, a terminal engaging portion (a nose) 31 is formed on an upper surface in the vicinity of the free end 27. The nose 31 has a rear part serving as an inclined surface 33 and a front part serving as an engaging portion 35. When the terminal fitting 19 is to be inserted, a front end 37 of an electrical contact portion (see FIG. 5 ) of the terminal fitting 19 abuts on the inclined surface 33, so that a component of force is generated by which the flexible engagement member 29 is pressed downward into the crush space 17 a. When the flexible engagement member 25 elastically returns to its initial position, the engagement portion 35 is engaged with an engagement hole 39 (see FIG. 5 ) of the terminal 19, so that rearward movement of the terminal 19 is controlled.In the flexible engaging member 25, the nose 31 formed at the free end 27 and engaged with the terminal fitting 19 has the shape of an inclined surface 29 in which a height of an upper portion 41 gradually increases from the front end 27 toward the base end so that a maximum shearing surface is generated by a shearing force of the terminal fitting 19 (an open edge of the engaging hole 39).In the embodiment, the inclined surface 29 has an inclination angle along a course 43 (see FIG. 6 ) of shear fracture in the nose 31. The inclined surface 29, which is the upper surface of the nose 31, is formed at the inclination angle along the course 43 of shear fracture. Therefore, when shear fracture occurs in the nose 31, a direction of propagation of the fracture almost coincides with the longest direction of the shape of the nose. That is, it is possible to improve shear fracture strength by increasing a minimum nose volume, thus avoiding an unnecessary increase in material usage.Next, a function of the connector 11 having this structure will be described.FIG. 6 is a sectional view illustrating the vicinity of the nose and showing the course 43 of shear fracture.When the terminal fitting 19 is inserted through the terminal insertion hole 23 in the rear portion of the connector housing 13 upon insertion of the terminal fitting 19, a front end of the terminal fitting 19 abuts against the inclined surface 33 of the flexible engagement member 25. When the terminal fitting 19 is further inserted, the flexible engagement part 25 whose inclined surface 33 is pressed is elastically deformed by bending the free end 27 in a direction to move into the crush space 17 a.When the terminal fitting 19 is inserted to a predetermined position, the engaging hole 39 (the terminal engaging hole) of the terminal fitting 19 is coincident with the engaging portion 35, so that the flexible engaging member 25 returns to the initial position by an elastic restoring force. Therefore, the terminal fitting 19 is placed in an engagement state in which the engagement portion 35 enters the engagement hole 39. The terminal piece 19 whose engaging portion 35 is engaged with the engaging hole 39 is guided to be removed from the rear portion of the connector housing 13.The nose 31 with the flexible engaging member 25 includes a horizontal upper surface in the conventional tongue. In the case where the height of the nose 31 changes, the height of the entire nose of the tongue is increased / decreased. However, if the entire upper surface of the tab of the tongue is enlarged to enhance a holding force, a male tab of the mating terminal and the upper surface of the tab of the tongue may interfere with each other and a good engagement state cannot be established. Furthermore, the tab of the tongue does not normally break horizontally, as shear fracture of the tongue extends from a contact point 47 of a terminal front contact surface 45 downwardly toward the top surface of the tab 31 at an angle θ. This means that a simple increase in the height of the terminal front contact surface 45 does not result in an increase in shear strength, so that material is lost. In the described structure, a height of a rear end of the nose is increased only by the angle θ required for shearing. Therefore, by increasing a shearing area by the shearing force of the terminal 19, it is possible to more effectively increase the shearing force of the nose 31.That is, as the shear force increases to increase the holding force, the holding force may be increased via a minimal change in the height of the nose. The shear strength can be increased without increasing the height of the terminal front contact surface 45. A problem of interference with the mating connector tab is avoided and the increase in material can be minimized, which is advantageous from an ecological point of view. Furthermore, with a reduction in size and weight, the construction can be implemented more efficiently. Further, for releasing the terminal, the height of the front contact surface of the terminal 45 does not need to be increased. Therefore, it is possible to carry out the detachment in a conventional manner and more efficiently.The upper surface of the tab 31 for engaging the engaging hole 39 of the terminal fitting 19 is thus formed on the connector 11 by the inclined surface 29 whose height gradually increases toward the base end. In the nose 31, only the thickness of the upper portion 41 is increased. Therefore, by substantially increasing the shearing area by the shearing force of the joint 19, the resistance to shear fracture can be improved. Further, the height of the terminal front contact surface 45 is not increased. Therefore, interference with the male tab of the mating terminal can be reduced. Further, a degree of sticking of the tab 31 with respect to the engagement hole 39 is prevented from becoming too large. It is thus possible to prevent the release process from being impaired. Further, the material usage does not increase unnecessarily in the case where the height of the terminal front contact surface 45 is increased.Therefore, with the connector 11 according to the embodiment, a shear strength can be effectively improved, so that a holding force is strengthened despite a decrease in the holding force of the tongue caused by a reduction in size.The application is based on the patent application filed on 30.08.2010 (Japanese Patent Application No. 2010-192424).Industrial applicabilityAccording to the invention, there can be provided a connector by which a shear strength can be effectively improved to reinforce a holding force despite a reduction in a holding force of a tongue caused by a reduction in size.Explanation of Reference Numeral 11 Connector 17 Terminal accommodation chamber 19 Terminal fitting 25 Flexible engagement part 27 Free end 29 Inclined surface 31 Tab 41 Upper portion 43 Route

Claims

A connector (11) comprising: a flexible engaging member (25) having a base end supported in a cantilevered manner in a terminal receiving chamber (17) for receiving a terminal fitting (19) and capable of being elastically deformed, and having a free end (27) with which the terminal fitting (19) to be inserted into the terminal receiving chamber (17) is engaged, wherein the flexible engaging member (25), at the free end (37) of which a tab (31) with which the terminal fitting (19) is engaged, is in the form of an inclined surface (29) in which a height of an upper portion gradually increases from the free end (27) toward the base end so as to provide a maximum shearing surface by a shearing force of the terminal fitting (19), characterized in that, the inclined surface (29) has an inclination angle (θ) along a course of shear fracture in the nose (31).

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