A grommet and method for arranging the same and use thereof

Abstract: To securely prevent a wire group from being exposed to water when it is arranged in a water exposure area in a vehicle while being divided into two or more wire bundles. A conical large diameter portion 12 is provided at one end 11a of a cylindrical main tube 11 made of rubber or elastomer. The other end 11b of the main tube 11 is closed. Two cylindrical branch tubes 13, 14 project from the side surface of the main tube 11 in a direction substantially normal to the longitudinal direction of the main tube 11, and conical large diameter portions 13a, 14a are provided at the leading ends of the branch tubes 13, 14. Furthermore the present invention relates to a method for arranging such a grommet and an use thereof.

Description: The present invention relates to a grommet for protecting a wire group from water, preferably when arranging it while dividing it into two or more wire bundles in an automotive vehicle and is particularly designed to protect a wire group from water which is arranged between a roof and a back door of a hatch-back type automotive vehicle in which a back door window can be opened and closed independently of the opening and closing movement of a back door. Furthermore the present invention relates to a method for arranging such a grommet and an use thereof. As shown in FIG. 8, in order to arrange a wire group for supplying a power to a back door of a hatch-back type vehicle, a grommet 5 is used which includes a narrow tube portion 5a through which the wire group is to be passed and large diameter portions 5b, 5c provided at the opposite ends of the narrow tube portion 5a. One large diameter portion 5b of the grommet 5 is mounted in a through hole 2 formed in an end portion of a roof panel 1, and the other large diameter portion 5c thereof is mounted in a through hole 4 formed in a back door frame. A wire group W is arranged into the inside of a door through the through hole 2 of the roof panel 1, through the narrow tube portion 5a of the grommet 5 and through the through hole 4 of the back door frame 3. In some hatch-back type vehicles, a back door window mounted on a back door can be opened and closed independently of the opening and closing movement of the entire back door. In such hatch-back type vehicles, a back door frame has a double structure as shown in FIG. 9. The wire group is arranged while being divided and inserted into a through hole 4a formed in a door main frame 3a of the back door and a through hole 4b formed in a door window holding frame 3b. In this case, as shown in FIG. 10, grommets 10A, 10B, 10C are mounted in the respective through holes 2, 4a, 4b of the roof panel 1, the door main frame 3a and the window holding frame 3b, respectively. However, in a water exposure area (Y) between the roof panel 1 and the frames 3a, 3b of the back door, the wire group W is not covered by the grommet and, accordingly, there is a likelihood that water enters the inside of the roof or back door (inside the frame) by running between the wires of the wire group W. Thus, at the openings of the grommets 10A, 10B and 10C, a water stop material such as a hard resin is filled between the wires of the wire group W to fix the entire wire group. However, it takes a time and a high cost to fill the water stop material. Further, the water exposure area (Y) is visible from the outside and does not look nice because the wire group is exposed. JP-A-07 105775 discloses a twine type grommet for a wire harness having a main electric wire insertion part and an auxiliary electric wire insertion part wherein the parts are formed adjacently and in parallel with each other. Furthermore there is formed a layered bellows between the main electric wire insertion part and the auxiliary electric wire insertion part so that the two parts can easily tilt against each other. Grommets of this kind are used to ease tape winding work of respective wire insertion parts and wire harnesses. JP-A-06 276642 discloses a waterproofing structure for a wire harness consisting in covering a wire harness with a flexible waterproof resin tube of specified wall thickness having openings at its both ends and winding a waterproof tape on both ends, and fixing it closely to the peripheral surface of the wire harness. The present invention was developed in view of the above problems, and an object thereof is to securely prevent a wire group from being exposed to water when being arranged, preferably while being divided into two or more wire bundles in a water exposure area in a vehicle. This object is solved according to the invention by a grommet according to claim 1, a method for arranging a grommet according to claim 6 and a use thereof according to claim 8. Preferred embodiments of the invention are subject of the dependent claims. According to the invention, there is provided a grommet for a connection with at least two members being preferably displaceable with respect to each other, having a branch construction comprising a main tube through which a wire group is passed or passable, wherein the main tube is branched into at least two branch tubes, wherein the main tube and each of the branch tubes comprise a connection portion at their leading ends. Accordingly, there is provided a grommet in which the main tube is connectable to a first member and the two or more branch tubes are connectable to a further second member or preferably two further second and third members, wherein one branch tube is connected with the second and the other branch tube with a third member. Furthermore, each connection portion comprises a large diameter portion being formed at the leading ends of each of the two or more branched tubes and the main tube, respectively. According to the invention there is provided a grommet having a branch construction in which a tube through which a wire group is passed is branched into at least two tubes, wherein a large diameter portion is formed at the leading ends of each of the two or more branched tubes and the main tube and the large diameter portions are fitted or fittable into through holes of a member on which the grommet is mounted. With the grommet thus constructed, the large diameter portions at the leading ends of the main tube and the two or more branch tubes are fitted or fittable into the through holes of the member on which the grommet is mounted with the wire group passed through the respective tubes. Accordingly, the wire group can be securely protected from water even in the case that it is arranged in a water exposure area in a vehicle while being divided into wire bundles. Further preferably, the grommet is used for arranging a wire group from a roof to a back door of a hatch-back type vehicle, preferably in which a back door window can be opened and closed independently from the opening and closing movement of the back door, wherein two branch tubes project from preferably the side surface of the main tube which is preferably made of rubber or elastomer and has one end formed with the connection portion having preferably the large diameter portion and the other end closed; and a wire group is arranged or arrangeable through the main tube and through the two branch tubes while dividing into two wire bundles. The above grommet is or may be used for arranging a wire group from a roof to a back door of a hatch-back type vehicle in which a back door window can be opened and closed independently from the opening and closing movement of the back door, wherein two branch tubes project from the side surface of a main tube which is made of rubber or elastomer and has one end formed into a large diameter portion and the other end closed; large diameter portions are formed at the leading ends of the two branch tubes; and a wire group is arranged from the roof to the back door by fitting the large diameter portion formed at one end of the main tube into a through hole formed in a roof panel, passing the wire group pulled out of the through hole through the main tube and pulling it out through the openings at the leading ends of the two branch tubes while dividing into two wire bundles; and fitting the large diameter portions at the leading ends of the two branch tubes into through holes formed in a door main frame of the back door and a glass retaining frame. With this construction, the wire group can be arranged from the roof to the back door without being exposed to water in a water exposure area between the roof and the back door in the hatch-back type vehicle in which the back door window can be opened and closed independently of the opening and closing movement of the back door. Still further preferably, the main tube and the at least two branch tubes are separately formed, wherein the main tube comprises two or more junction tubes projecting from a surface, preferably a side surface thereof, wherein one end of at least two joint members preferably made of a resin tube is each fitted or fittable into the leading end of each of the at least two junction tubes, and wherein the distal or rear end of each branch tube having the connection portion, preferably the large diameter portion formed at the leading end thereof around the corresponding joint member. Preferably, a part of the main tube is formed into a corrugated portion being preferably arranged between its connection portion and the at least two branch tubes and preferably extending over substantially its full longitudinal extension. By doing so, the grommet can undergo a deformation according to the opening and closing operation of the back door and the back door window. This prevents the large diameter portions of the grommet from being disengaged from the main frame of the back door and the glass retaining frame. Preferably, the main tube and the two branch tubes are separately formed and are connected by forming two relatively short junction tubes projecting from the side surface of the main tube, fitting one end of a joint member made of a resin tube into the leading end of each of the two junction tube, and fitting the rear end of each branch tube having the large diameter formed at the leading end thereof around the corresponding joint member. With such a grommet, after the wire group is passed through the main tube, and the wire bundles are pulled out through the openings at the ends of the joint members and passed through the branch tubes, the branch tubes can be connected with the joint members. Therefore, the wire group can be more easily passed through the grommet. According to a further preferred embodiment, at least part or one of the junction tubes projecting from the surface, preferably the side surface of the main tube and the corresponding branch tubes have the same elliptical or oblong cut section and the corresponding connection portions, preferably the corresponding large diameter portions at the leading ends of the corresponding branch tubes are so formed as to be widened along a direction at an angle different from 0° or 180°, preferably substantially normal to the longitudinal axes of the branch tubes. Further preferably, the junction tubes projecting from the side surface of the main tube and the branch tubes have the same elliptical or oblong cut section and the large diameter portions at the leading ends of the branch tubes are so formed as to be widened along a direction substantially normal to the longitudinal axes of the branch tubes. Such a grommet can be easily assembled such that the widening direction of the large diameter portions of the branch tubes and that of the large diameter portion of the main tube have a specified relationship. According to the invention, there is further provided a method for arranging a grommet according to one or more of the preceding claims for connecting at least two members, being preferably displaceable with respect to each other, comprising the steps of connecting the main tube to the first member and connecting the branch tubes to the second member, preferably separately to the second and the third member being displaceable with respect to each other. Accordingly, the wire group arranged in the water exposure area of the vehicle while being divided can be covered by the grommet. Accordingly, the wire group can be securely protected from water. The method further comprises the steps of: arranging a wire group from the first member, preferably a roof to the second member, preferably a back door of a hatch-back type vehicle, in which the third member, preferably a back door window is displaceable or movable independently from the movement of the second member, wherein the back door window preferably can be opened and closed independently from the opening and closing movement of the back door; fitting the connection portion, preferably the large diameter portion formed at one end of the main tube into a through hole formed in the first member, preferably a roof panel, passing the wire group pulled out of the first member through hole through the main tube and pulling it out through openings at the leading ends of the two branch tubes while dividing into two wire bundles; and fitting the connection portions, preferably the large diameter portions at the leading ends of the two branch tubes into through holes formed in the second and third members, preferably in a door main frame of the back door and a glass retaining frame. Accordingly, the wire group can be arranged from the roof to the back door without being exposed to water in a water exposure area between the roof and the back door in the hatch-back type vehicle in which the back door window can be opened and closed independently of the opening and closing movement of the back door. Preferably, the method further comprises the steps of: separately forming the main tube and the at least two branch tubes and connecting them by forming at least two relatively short junction tubes projecting from a surface, preferably a side surface of the main tube, fitting one end of at least two joint members preferably made of a resin tube each into the leading end of each of the at least two junction tubes, and fitting the rear end of each branch tube having the connection portion, preferably the large diameter portion formed at the leading end thereof around the corresponding joint member. According to the invention, there is further provided a use of the inventive grommet for arranging a wire group from a roof to a back door of a hatch-back type vehicle in which a back door window can be opened and closed independently from the opening and closing movement of the back door. These and other objects, features and advantages of the present invention will become more apparent upon a reading of the following detailed description and accompanying drawings in which: FIG. 1 is a perspective view of a grommet according to a first embodiment, FIG. 2 is a schematic section of an arrangement construction of a wire group using the grommet of FIG. 1, FIG. 3 is a perspective view of a grommet according to a second embodiment, FIGS. 4(A) and 4(B) are perspective views showing an operation of inserting a wire group into the grommet of FIG. 3, FIG. 5 is a perspective view of a grommet according to a third embodiment, FIG. 6 is a perspective view of a prior art grommet, FIG. 7 is a perspective view of a roof panel and a back door frame, FIG. 8 is a schematic section of an arrangement construction of a wire group using the grommet of FIG. 6, FIG. 9 is a perspective view of a roof panel and a back door frame, and FIG. 10 is a schematic section showing an arrangement construction of a wire group between the roof panel and the back door frame shown in FIG. 9. Hereafter, embodiments of the invention are described with reference to the drawings. FIG. 1 shows a grommet according to a first embodiment for protecting a bundle of wires from water which is to be arranged e.g. from a roof side to a hatch-back door having a window which can be opened and closed independently from the opening and closing movement of the back door. A grommet 100 is made e.g. of rubber or elastomer. A large diameter portion 12 (connection portion) is provided at one end 11a of a substantially cylindrical main tube 11, and the other end 11b of the main tube 11 is or may be closed. Two substantially cylindrical branch tubes 13, 14 project from the side surface of the main tube 11 in a direction at an angle different from 0° or 180°, preferably substantially normal to the longitudinal direction of the main tube 11, and large diameter portions 13a, 14a (connection portions) are provided preferably at the leading ends of the branch tubes 13, 14. The large diameter portion 12 provided at the end 11a of the main tube 11 is formed into a flange. Further, a corrugated portion 15 is provided at a part of the main tube 11, preferably between the large diameter portion 12 and the branch tubes 13, 14, so as to permit a loose movement of the main tube 11. The large diameter portions 13a, 14a at the leading ends of the branch tubes 13, 14 are widened such that the openings at the leading ends thereof face in a direction at an angle different from 0° or 180°, preferably substantially normal to the longitudinal direction of the branch tubes 13, 14. The widening direction (opening direction) of the large diameter portions 13a, 14a are substantially same as the widening direction (opening direction) of the large diameter portion 12 of the main tube 11. FIG. 2 shows a wire group arranged from a roof side to a back door using the grommet 100. The large diameter portion 12 in the form of a flange at one end of the main tube 11 of the grommet 100 is fitted to a projecting rim of a through hole 24a formed in a roof panel 24, whereas the large diameter portions 13a, 14a at the leading ends of the branch tubes 13, 14 are fitted into through holes 21a, 22a formed in a door main frame 21 and a door glass retaining frame 22, respectively. A wire group W is inserted or insertable into the main tube 11 through the through hole 24a of the roof panel 24 and divided preferably into wire bundles W1, W2, which are passed through the branch tubes 13, 14 and pulled out through the through hole 21 a of the door main frame 21 and the through hole 22a of the frame 22 for retaining a door glass 25. In this way, the wire group W is arranged from the roof side to the back door. Thus, the wire group W is covered by the grommet 100 in a water exposure area (Y) between the roof panel 24 and the frames 21, 22 of the back door, i.e. completely protected from water. Further, since the grommet 100 is made e.g. of rubber or elastomer and the main tube 11 is permitted to make a loose movement because of the corrugated portion 15, the grommet 11 undergoes a deformation as the back door or the back door window is opened and closed. Accordingly, there is no likelihood that the respective large diameter portions 12, 13a, 14a of the main tube 11 and the branch tubes 13, 14 are disengaged from the roof panel 24 and the frames 21, 22 of the back door. FIG. 3 shows a grommet 200 according to a second embodiment. The grommet 200 is constructed as follows. Two relatively short preferably cylindrical junction tubes 31 a, 31 b project from the side surface of a cylindrical main tube 11 made of rubber or elastomer, and branch tubes 32, 33 e.g. made of rubber or elastomer and each formed with a substantially conical large diameter portion 34 at one end are connected with the leading ends of the two junction tubes 31a, 31b via joint members 35 each formed of a material having a stiffness or rigidity being preferably higher than that of the main tube 11 and/or the branch tubes 13, 14, e.g. of a resin cylindrical tube. Elongated and preferably circumferentially continuous projections 36, 37, 38 are formed on the outer surface of the joint member 35 at the substantially opposite ends and substantially in the middle with respect to the longitudinal direction of the joint member 35, respectively. The outer diameter of the joint member 35 at one end is slightly larger than the inner diameter of the branch tube 32 (33). This, together with the projection 36 formed at this end, makes the branch tube 32 fitted around the joint member 35 unlikely to come off and substantially seleangly engaged. The outer diameter of the other end of the joint member 35 is larger than the inner diameter of the junction tube 31a (31b). This, together with the projection formed at this end, makes the junction tube 31 a (31 b) fitted around the joint member 35 unlikely to come off. The projection 38 formed substantially in the middle of the joint member 35 along the longitudinal direction is a stopper for restricting the insertable length of the joint member 35 into the branch tube 32 (33) and the junction tube 31a (31b). In the grommet 200, as shown in FIG. 4(A), a wire group W inserted or insertable into the main tube 11 is pulled out through the cylindrical junction tubes 31a, 31b while being divided into wire bundles W1, W2 before the branch tubes 32, 33 are mounted, and the joint members 35 are fitted into the junction tubes 31a, 31b. Thereafter, as shown in FIG. 4(B), the wire bundles W1, W2 are inserted or insertable into the branch tubes 32, 33 and pulled out through the openings at the leading ends of the conical large diameter portions 34 at one end of the branch tubes 32, 33 and, then, the other ends of the branch tubes 32, 33 are fitted around the joint members 35. Accordingly, as compared with the grommet 100 of the first embodiment in which the main tube and the branch tubes are integral or unitary, the wire group W can be more easily passed through the grommet 200. FIG. 5 shows a grommet 300 according to a third embodiment. The grommet 300 is constructed as follows. The junction tubes 31a, 31b projecting from the side surface of the main tube 11 and branch tubes 32, 33 have an elliptical cut section. The major axes of the cut sections of the junction tubes 31a, 31b substantially conform to those of the branch tubes 32, 33 and the junction tubes 31a, 31b and the branch tubes 32, 33 are connected via the joint members 35, so that the widening direction (opening direction) of the large diameter portion 12 of the main tube 11 conforms to the widening direction (opening direction) of the large diameter portions 34 of the branch tubes 32, 33. By the above construction, by connecting the junction tubes 31 a, 31b with the branch tubes 32, 33 in such a manner as to substantially conform the major axes of the junction tubes 31a, 31b of the main tube 11 to those of the branch tubes 32, 33, the grommet 300 can be easily assembled such that the large diameter portions 34 of the branch tubes 32, 33 are widened in the same direction as the conical large diameter portion 12 of the main tube 11. The reason why the large diameter portions 34 of the branch tubes 32, 33 are widened in the same direction as the large diameter portion 12 of the main tube 11 in this embodiment is to construct the grommet 300 such that it undergoes a deformation as the back door or back door window is opened and closed in a vehicle in which it is used. Thus, the grommet 300 can easily realize a construction during assembling which is suited to being deformed as the back door or back door window is opened and closed. In the foregoing embodiments, one wire group is arranged from the roof to the hatch-back door while being divided into two wire bundles. However, a branch construction in which the tube through which the wire group is passed or passable is branched into three or more tubes and a large diameter portion is formed at the leading end of each of the three branch tubes may be adopted so that the wire group can be protected from water in the case that it is arranged while being divided into three or more wire bundles. Furthermore, the cross sections of the main tube, branch tubes and/or portions may be different from circular or elliptical depending upon its/their application, e.g. rectangular, polygonal or the like. Furthermore, the grommet may be adopted or arranged between two parts or members (other than at a back door of a hatch-back type vehicle) being movable or displaceable with respect to each other, e.g. a door and a body of a vehicle or the like. LIST OF REFERENCE NUMERALS 11 Main Tube 12, 13a, 14a Large Diameter Portion 13, 14 Branch Tube 15 Corrugated Portion 21 Door Main Frame 21a, 22a, 24a Through Hole 22 Glass Retaining Frame 24 Roof Panel W Wire Group W1, W2 Wire Bundle

Claims: A grommet (100; 200; 300) for a connection with at least two members (21; 22; 24) being preferably displaceable with respect to each other, having a branch construction comprising a main tube (11) through which a wire group is passed or passable, wherein the main tube is branched into at least two branch tubes (13, 14; 32, 33), wherein the main tube (11) and each of the branch tubes (13, 14; 32, 33) comprise a connection portion (12, 13a, 14a; 34) at their leading ends, the main tube connectable to a first member (24) and branch tubes connectable to a further second member (21,22) or preferably two further second and third members (21,22), wherein one branch tube is connected with the second member (21) and the other branch tube with the third member (22) characterized in that each connection portion (12, 13a, 14a; 34) comprises a large diameter portion (12; 13a; 14a; 34) being formed at the leading ends of each of the two or more branched tubes (13, 14; 32, 33) and the main tube (11), respectively; and said large diameter portion (12; 13a; 14a; 34) being configured to sealingly engage respective through holes (21a; 22a; 24a) of said members (21; 22; 24). A grommet according to claim 1, used for arranging a wire group from a roof to a back door of a hatch-back type vehicle, preferably in which a back door window can be opened and closed independently from the opening and closing movement of the back door, wherein two branch tubes (13, 14; 32, 33) project from preferably the side surface of the main tube (11) which is preferably made of rubber or elastomer and has one end (11a) formed with the connection portion (12) having preferably the large diameter portion (12) and the other end (11b) closed; and a wire group (W) is arranged or arrangeable through the main tube (11) and through the two branch tubes (13, 14; 32, 33) while dividing into two wire bundles (W1, W2). A grommet according to one or more of the preceding claims, wherein the main tube (11) and the at least two branch tubes (32, 33) are separately formed, wherein the main tube (11) comprises two or more junction tubes (31a, 31b) projecting from a surface, preferably a side surface thereof, wherein one end of at least two joint members (35) preferably made of a resin tube is each fitted or fittable into the leading end of each of the at least two junction tubes (31a, 31b), and wherein the distal end of each branch tube 32, 33) having the connection portion (34), preferably the conical large diameter portion (34) formed at the leading end thereof is fitted or fittable around the corresponding joint member (35). A grommet according to claim 3, wherein at least part of the junction tubes (35) projecting from the surface, preferably the side surface of the main tube (11) and the corresponding branch tubes (34) have the same elliptical or oblong cut section and the corresponding connection portions (34), preferably the corresponding large diameter portions (34) at the leading ends of the corresponding branch tubes (32, 33) are so formed as to be widened along a direction at an angle different from 0° or 180°, preferably substantially normal to the longitudinal axes of the branch tubes (32, 33). A grommet according to one or more of the preceding claims, wherein the main tube (11) comprises a corrugated portion (15) being arranged between its connection portion (12) and the at least two branch tubes (13, 14; 32, 33) and preferably extending over substantially its full longitudinal extension. A method for arranging a grommet (100; 200; 300) according to one or more of the preceding claims for connecting at least two members (21; 22; 24), being preferably displaceable with respect to each other, comprising the steps of arranging a wire group (W) from the first member (24), preferably a roof to the second member (21), preferably a back door of a hatch-back type vehicle, in which the third member (22), preferably a back door window (23) is displaceable or movable independently from the movement of the second member (21), wherein the back door window (23) preferably can be opened and closed independently from the opening and closing movement of the back door (21); passing the wire group (W) pulled out of the first member through hole (24a) through the main tube (11) and pulling it out through openings at the leading ends of the two branch tubes (13, 14; 32, 33) while dividing into two wire bundles (W1, W2); characterized by fitting the large diameter portion formed at one end (11a) of the main tube (11) into a through hole (24a) formed in the first member (24), preferably a roof panel (24), and fitting the large diameter portions (13a, 14a; 34) at the leading ends of the two branch tubes (13, 14; 32, 33) into through holes (21a, 22a) formed in the second and third members (21, 22), preferably in a door main frame (21) of the back door and a glass retaining frame (22). A method according to claim 6, further comprising the steps of: separately forming the main tube (11) and the at least two branch tubes (13, 14; 32, 33) and connecting them by forming at least two relatively short junction tubes (31a, 31b) projecting from a surface, preferably a side surface of the main tube (11), fitting one end of at least two joint members (35) preferably made of a resin tube each into the leading end of each of the at least two junction tubes (31a, 31b), and fitting the rear end of each branch tube (13, 14; 32, 33) having the connection portion (13a, 14a; 34), preferably the large diameter portion (13a, 14a; 34) formed at the leading end thereof around the corresponding joint member (35). A use of a grommet (100; 200; 300) according to one or more of the preceding claims 1 to 5 for arranging a wire group (W) from a roof (24) to a back door (21) of a hatch-back type vehicle in which a back door window (22) can be opened and closed independently from the opening and closing movement of the back door (21).

Inventors: MORI KEISUKE, MORI, KEISUKE
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 1998
Main classification: B60R16
IPC codes: H02G3, B60R16, F16L5, H01B17