Abstract:
A first connector housing is provided with a first guide member extending in a first direction. A second connector housing is adapted to be fitted with the first connector housing in the first direction. The second connector housing is provided with a second guide member extending in the first direction. The first guide member and the second guide member are so configured as to guide a fitting operation of the first connector housing and the second connector housing while being brought into points or line contact with each other.

Description:
BACKGROUND OF THE INVENTION 
   This invention relates to a connector in which a pair of connector housings are fitted together while their fitting operation is guided, and the two connectors are electrically connected together. 
     FIGS. 5 and 6  show one a related-art connector disclosed in, for example, Japanese Patent Publication No. 2002-198127A (see the descriptions in pages  3  and  4 , and FIGS.  5  and  6 ). 
   The connector  50  comprises female and male connector housings  51  and  55  which can be fitted together. The female connector housing  51  includes a peripheral wall  52  of a substantially square tubular shape formed integrally with an equipment, and male terminals  54  project into the interior of the peripheral wall  52 . A locking projection  53  is formed on and projects upwardly from an upper surface of the peripheral wall  52 , and is disposed substantially at a widthwise-central portion of this upper surface. A locking arm  58  on the male connector housing  55  is retainingly engageable with the locking projection  53 . 
   A pair of upwardly-projecting guide ribs  60  are formed on the peripheral wall  52 , and are disposed at opposite sides of the locking projection  53 , respectively, the guide ribs  60  extending in a forward-rearward direction (i.e., the fitting direction) over an entire length of the peripheral wall  52 . Also, a pair of guide ribs  61  are formed respectively on opposite side surfaces of the peripheral wall  52 . 
   The male connector housing  55  includes a terminal receiving portion  56  for receiving female terminals  59 , and a tubular portion  57  integrally connected to this terminal receiving portion  56  in surrounding relation thereto. The peripheral wall  52  can be fitted into a space between the terminal receiving portion  56  and the tubular portion  57 . 
   The locking arm  58  is formed on a widthwise-central portion of an upper portion of the tubular portion  57 . A locking hole  58   a  is formed through the locking arm.  58  in a direction perpendicular to the fitting direction, and the locking projection  53  on the female connector housing  51  is retainingly engageable in the locking hole  58   a . 
   Recessed portions  62 , corresponding respectively to the guide ribs  60 , are formed at opposite sides of the locking arm  58 , respectively. As the two connector housings  51  and  55  are fitted together, the guide ribs  60  are inserted into the recessed portions  62 , respectively. Protruded portions  64 , each having a guide groove  63  therein, are formed at opposite side portions of the tubular portion  57 , respectively. The pair of guide ribs  61 , formed respectively on the opposite side surfaces of the peripheral wall  52 , can be inserted into the guide grooves  63 , respectively. 
   When the male connector housing  55  is fitted into the female connector housing  51 , the peripheral wall  52  is inserted into the space between the tubular portion  57  and the terminal receiving portion  56 , and the guide ribs  60  are inserted respectively into the recessed portions  62 , and the guide ribs  61  are inserted respectively into the guide grooves  63 , so that the fitting operation of the two connector housings  51  and  55  is carried out. 
   However, the above connector  50  has the following problems to be solved. 
   The fitting operation of the two connector housings  51  and  55  are carried out while the guide ribs  60  and  61 , formed respectively at the four portions of the peripheral wall  52 , are held in face-contact with the recessed portions  62  and guide groove portions  63  (which are formed at the tubular portion  57 ), respectively. Therefore, there is encountered a problem that the sliding resistance increases, so that the fitting operation can not be effected smoothly. 
   When the two connector housings  51  and  55  are fitted together, the sliding resistance due to the sliding contact between the male terminals  54  and the female terminals  59  is added to the sliding resistance due to the sliding contact between the guide ribs  60  and the recessed portions  62 , and the sliding resistance due to the sliding contact between the guide ribs  61  and the guide groove portions  63 . Therefore, the total sliding resistance becomes large. Particularly in the case of the multi-pole connector, the sliding resistance, produced by the terminals  54  and  59 , becomes large, and the efficiency of the fitting operation is lowered. When the sliding resistance increases, so that the efficiency of the fitting operation is lowered, the automation of a connector-assembling line can not be achieved. 
   Therefore, in order to reduce the sliding resistance between each guide rib  60  and the corresponding recessed portion  62  and to reduce the sliding resistance between each guide rib  61  and the corresponding guide groove portion  63 , it may be proposed to provide a clearance or gap between the sliding surfaces of each guide rib and the corresponding portion. However, when such clearances are provided, the two connector housings  51  and  55  shake relative to each other during the fitting operation, so that the guiding performance is adversely affected. As a result, in some cases, the male terminal  54  strikes against the female terminal  59 , and a tab-like electrical contact portion of the male terminal  54  is bent, and a box-like electrical contact portion of the female terminal  59  is deformed. 
   In the case where the connector  50  is used in an engine room of an automobile, a household electrical appliance (in which vibrations occur) or others, external vibrations are transmitted to the connector  50 , thereby inviting a problem that the two terminals  54  and  59  rub each other, and are subjected to the frictional wear or corrosion. 
   SUMMARY OF THE INVENTION 
   It is an object of the invention to provide a connector in which a sliding resistance, developing between each guide rib and a corresponding guide groove, is reduced so as to enable a smooth fitting operation, thereby enhancing the efficiency of the fitting operation. 
   In order to achieve the above object, according to the invention, there is provided a connector, comprising:
         a first connector housing, comprising a first guide member extending in a first direction; and   a second connector housing, adapted to be fitted with the first connector housing in the first direction, the second connector housing comprising a second guide member extending in the first direction,   wherein the first guide member and the second guide member are so configured as to guide a fitting operation of the first connector housing and the second connector housing while being brought into points or line contact with each other.       

   In the above configuration, the pair of connector housings are positioned relative to each other in a direction perpendicular to the first direction, while the fitting operation of the two connector housings is guided. Therefore, the pair of connector housings are prevented from shaking relative to each other, and the erroneous insertion of terminals are prevented, and the mating terminals are positively electrically connected together. 
   The guide members, which cooperate with each other to guide the fitting operation, are brought into points or line contact with each other. Therefore, the sliding resistance, developing between the guide members during the fitting operation, is reduced, and the pair of connector housings are fitted together with a lower fitting force. 
   Preferably, the first guide member is a rib member and the second guide member is a groove into which the rib member is inserted while being guided. 
   In this case, there can be provided the low-fitting-force connector with a simple structure. 
   Here, it is preferable that one of the rib member and the groove is formed with protrusions, and the other one of the rib member and the groove is formed with flat faces on which the protrusions are slid when the fitting operation is performed. 
   In this case, the points or line contact of the guide members are realized by the projections and the flat faces to reduce the sliding resistance. 
   Here, it is further preferable that the protrusions are formed on the rib member, and a proximal portion of each of the protrusions is narrowed. 
   In this case, since the narrowed proximal portion of the rib member will not interfere with edges of the groove, the fitting operation of the pair of connector housings is carried out smoothly. 
   It is also preferable that the protrusions are arranged in the first direction. According to the points contact between the protrusions and the flat faces, the sliding resistance can be reduced remarkably. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above objects and advantages of the present invention will become more apparent by describing in detail preferred exemplary embodiments thereof with reference to the accompanying drawings, wherein: 
       FIG. 1  is a transverse cross-section view of a connector according to one embodiment of the invention, showing an assembled condition; 
       FIG. 2  is an exploded, longitudinal cross-section view of the connector of  FIG. 1 ; 
       FIG. 3A  is an enlarged transverse section view of a guide rib and a guide groove in the connector of  FIG. 1 ; 
       FIG. 3B  is an enlarged transverse section view of a modified example of the guide rib and the guide groove; 
       FIG. 4A  is an enlarged longitudinal section view of the guide rib and the guide groove in the connector of  FIG. 1 ; 
       FIG. 4B  is an enlarged longitudinal section view of the modified example of the guide rib and the guide groove; 
       FIG. 5  is an exploded, longitudinal cross-section view of a related-art connector; and 
       FIG. 6  is a transverse cross-section view of the related-art connector, showing an assembled condition. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 
   As shown in  FIGS. 1 and 2 , a connector  10  according to one embodiment of the invention comprises a female connector housing  12 , and a male connector housing  20 . Guide ribs  17  and guide grooves  37  linearly guide the fitting operation of the pair of connector housings  12  and  20 , and a feature of this connector  10  resides in the fact that each guide rib  17  and the corresponding guide groove  37  contact each other at a plurality of points or a plurality of lines. 
   In this specification, the connector housing in which male terminals  13  are received is defined as the female connector housing  12 , and the connector housing in which female terminals  21  are received is defined as the male connector housing  20 . Each of the pair of connector housings  12  and  20  is injection molded into an integral construction, using a synthetic resin material. 
   The female connector housing  12  is the equipment-side connector housing which is mounted directly on an on-vehicle equipment of an automobile, and is disposed in a waiting condition. This female connector housing  12  has a connector fitting chamber  19  (for receiving an inner housing  26  of the male connector housing  20  therein) formed inside an annular peripheral wall (wall portion)  15 . 
   The male terminals  13  are so disposed as to be opposed respectively to terminal passage holes  27  in the male connector housing  20 , and project into the interior of the connector fitting chamber  19 , and extend forwardly in a fitting direction. When the pair of connector housings  12  and  20  are fitted together, a tab-like electrical contact portion  14  of each male terminal  13 , while guided by the terminal passage hole  27 , is inserted into an electrical contact portion  22  of the corresponding female terminal  21 . 
   An engagement groove  16  for retaining engagement with a locking arm  25  of the male connector housing  20  is formed in an upper wall  15   a  of the peripheral wall  15 , and is disposed at a substantial widthwise center of the upper wall  15   a . A vertical retaining surface  16   a  is formed at the front side of the retaining groove  16 , and a distal end portion  25   a  of the locking arm  25  is retained by this retaining surface  16 , thereby holding the pair of fitted connector housings  12  and  20  against withdrawal. 
   As shown in  FIG. 1 , the outwardly-projecting guide ribs  17  are formed respectively on opposite side walls  15   c  and lower wall  15   b  of the peripheral wall  15 , and extend in the fitting direction. The guide ribs  17  are thus formed at the three portions, respectively, and when these guide ribs  17  are engaged respectively in the guide grooves  37  in the male connector housing  20 , the male connector housing  20  (which is fitted into the female connector housing) is positioned in two perpendicularly-intersecting directions in a plane perpendicular to the fitting direction. The number of the guide ribs  17  is arbitrary, and can be two or more than three. 
   Namely, the positioning in an upward-downward direction X is effected by the pair of guide ribs  17  formed respectively on the opposite side walls  15   c , and the positioning in a right-left direction Y is effected by the guide rib  17  formed on the lower wall  15   b . Although any guide rib is not formed on the upper wall  15   a , guide ribs can be formed at the opposite sides of the engagement groove  16 , respectively. 
   As shown in  FIG. 3A , the guide rib  17  is thinned (reduced in thickness) at its proximal portion (which is integrally connected to the side wall  15   c .) so that the guide rib  17  will not interfere with opposed corner portions  37   b  of the guide groove  37 . A gap is formed between each corner portion  37   b  and the proximal portion, so that the guide rib  17  can be smoothly inserted into the guide groove  37 . The guide rib includes protrusions on side surfaces  17   a  which project from the thinned portion. 
   According to the above configuration, the connector fitting operation is carried out, with the side surfaces of the distal end portion of the guide rib  17  held in line-contact respectively with opposed groove surfaces (sliding surfaces)  37   a  of the guide groove  37 . 
     FIG. 3B  shows a modified example of the guide rib  17  and the guide groove  37 . In this case, each of opposed groove surfaces  37   a  of the guide groove  37  is formed into a convexly-curved surface (i.e., a protrusion), while each of opposite side surfaces  17   a  of the guide rib  17  is formed into a flat surface. The connector fitting operation is carried out, with the guide rib  17  held in line-contact with the guide groove  37 . In this modified example, the proximal portion of the guide rib  17  is kept thick, so that there is an advantage that the strength of the guide rib  17  increases. 
   The guide rib  17  and the guide groove  37  are thus held in line-contact with each other, and therefore a sliding resistance, developing between the guide rib  17  and the guide groove  37  during the connector fitting operation is reduced, and the pair of connector housings  12  and  20  are fitted together with a lower fitting force, and the connector fitting operation is carried out smoothly, so that the efficiency of the fitting operation is enhanced. 
   With the simple improvement in which one of the guide rib  17  and the guide groove  37  is changed in shape, the low-insertion-force connector  10  can be obtained. 
   Another feature of the present invention resides in that each of the sliding surfaces (i.e., the opposite side surfaces  17   a  or the opposed groove surfaces  37   a ) of one of the guide rib  17  and the guide groove  37  is formed into a corrugated surface extending in the fitting direction Z, while each of the sliding surfaces of the other is formed into a flat surface as shown in  FIGS. 4A and 4B . 
     FIG. 4A  shows one example in which the groove surfaces  37   a  of the guide groove  37  are corrugated.  FIG. 4B  shows another example in which the side surfaces  17   a  of the guide rib  17  are corrugated. Thus, the sliding surfaces of one of the guide rib and the guide groove are made corrugated, so that the guide rib  17  and the guide groove  37  contact each other at discrete points, and the areas of contact between the two are made smaller as compared with the case where the guide rib and the guide groove contact each other at surfaces or lines. Therefore, the sliding resistance can be markedly reduced. 
   The male connector housing  20  is the harness-side connector housing connected to wires  45 , and is fitted into the female connector housing  12  disposed in a waiting condition. 
   The male connector housing  20  includes the tubular inner housing  26 , and the outer housing  36  surrounding the inner housing  26 . The inner housing  26  has terminal receiving chambers  28  formed therein, and the female terminals  21 , connected respectively to end portions of the wires  45 , are received in these terminal receiving chambers  28 , respectively. 
   The female terminal  21  is formed by blanking a piece from an electrically-conductive sheet and then by bending this piece. The female terminal  21  includes the electrical contact portion  22  formed at one end thereof, and a wire connection portion  24  formed at the other end thereof. The electrical contact portion  22  has a box-like shape, and a resilient contact piece portion  23  of a curved shape for contact with the male terminal  13  is provided within this electrical contact portion  22 . The wire  45  passing through a waterproof rubber plug  35  is clamped by the wire connection portion  24 . 
   The rubber plug  35  is a bellows tube, and is held in intimate contact with an inner surface of the terminal receiving chamber  28 . With this construction, water drops, moving along the wire  45 , are prevented from intruding into the terminal receiving chamber  28 . 
   A housing lance  30  is formed on a lengthwise-central portion of the upper surface of each terminal receiving chamber  28 , and projects forwardly therefrom. A retaining surface  30   a  is formed at a distal end of the housing lance  30 . This retaining surface  30   a  abuts against a retaining portion  22   a , formed at the electrical contact portion  22  of the female terminal  21  inserted in the terminal receiving chamber  28 , thereby retaining the female terminal  21 . 
   A flexure space  31  for the housing lance  30  is formed at the upper side of the housing lance  30 . The housing lance  21  is pushed upwardly by the female terminal  21 , thereby allowing the insertion of the female terminal  21 . When a projecting portion  34   a  of a front holder  34 , attached to a front end portion of the inner housing  26 , is inserted into the flexure space  31 , this projecting portion  34   a  prevents the elastic deformation of the housing lance  30 , thereby preventing the rearward withdrawal of the female terminal  21 . 
   A waterproof ring  33  is fitted on an inner rear end portion of the inner housing  26 , and this waterproof ring  33  is held in intimate contact with the inner peripheral surface of the peripheral wall  15  to form a waterproof seal between the pair of connector housings  12  and  20 . 
   The outer housing  36  has a substantially square tubular shape, and is integrally connected to the rear end portion of the inner housing  26 , and extends in the fitting direction Z. The front end of the outer housing  36  projects forwardly beyond the front end of the inner housing  26  in the fitting direction Z so as to be opposed to a flange portion  18  of the female connector housing  12 . 
   The guide grooves  37 , corresponding respectively to the guide ribs  17  formed respectively at the three portions of the peripheral wall  15  of the female connector housing  12 , are formed in the inner surface of the outer housing  36 . The guide ribs  17  are engaged respectively in the guide grooves  37  so that the connector fitting operation can be carried out smoothly. 
   An annular fitting space  42  is formed between the inner housing  26  and the outer housing  36 , and the female connector housing  12  is fitted into this fitting space  42 . The peripheral wall  15  of the female connector housing  12  closely fits in this fitting space  42 . 
   For assembling the connector  10 , the male connector housing  20  is opposed to the female connector housing  12 , and then the pair of connector housings  12  and  20  are moved toward each other, and the guide ribs  17  are engaged in the guide grooves  37 , respectively, and the peripheral wall  15  is pushed into the annular fitting space  42 , thereby assembling the connector. The sliding resistance, developing between each guide rib  17  and the corresponding guide groove  37 , is small, and therefore the pair of connector housings  12  and  20  are fitted together with a lower fitting force. 
   Although the present invention has been shown and described with reference to specific preferred embodiments, various changes and modifications will be apparent to those skilled in the art from the teachings herein. Such changes and modifications as are obvious are deemed to come within the spirit, scope and contemplation of the invention as defined in the appended claims.