Patent Publication Number: US-2011061897-A1

Title: Grommet

Description:
FIELD OF THE INVENTION 
     This invention relates to a grommet and more particularly relates to a grommet that is mounted on a wire harness to be wired in a motor vehicle and is attached to a through-hole in a vehicle body panel to protect, waterproof, and dustproof a portion of the wire harness inserted in the through-hole. 
     BACKGROUND OF THE INVENTION 
     Heretofore, a wire harness to be wired from an engine room in a motor vehicle to a passenger room mounts a grommet made of rubber or elastomer, and the grommet is attached to a through-hole provided in a vehicle body panel for partitioning a vehicle body of the motor vehicle into the engine room and the passenger room so as to protect the wire harness passing the through-hole and to waterproof, dustproof, and sound-insulate from an engine room side to a passenger room side. 
     The present applicant has proposed a grommet shown in  FIG. 8A  and disclosed in JP 2007-135253 A (Patent Document 1). In the grommet, an enlarging diameter tubular section  100  is provided in an outer peripheral surface of an larger diameter side with a vehicle body latch recess  102 . Closing surface portions  103 A and  103 B are provided on an inner peripheral surface of a larger diameter side end of the enlarging diameter tubular section  100 . A pair of half cylindrical portions  104 A and  104 B protrude from opposed central parts of the respective closing surface portions  103 A and  103 B. A smaller diameter tubular section  105  passes a central part of the enlarging diameter tubular section  100  from a smaller diameter end side of the enlarging diameter section  100 . The smaller diameter tubular section  105  protrudes an inner tube  105   a  in a central area between the pair of half cylindrical portions  104 A and  104 B. 
     As shown in  FIG. 8B , in the above grommet, after a wire harness W/H passes through the smaller diameter tubular section  105  that protrudes to the larger diameter side to penetrate the enlarging diameter section  100 , a tape T is wound around an outer peripheral surface of the pair of half cylindrical portions  104 A and  104 B at the outer peripheral side of the inner tube  105   a  that is provided at a protruding side of the smaller diameter tubular section  105 , and also the tape T is wound around an outer peripheral surface of the wire harness W/H drawn out from the inner tube  105   a , thereby securing the wire harness W/H to the grommet. 
     In the grommet disclosed in Patent Document 1, since the smaller diameter tubular section does not protrude outward from the smaller diameter side of the enlarging diameter tubular section  100  but extends from the section  100  to a larger diameter side, there is an advantage that a length of the grommet can be shortened. 
     However, in the case where the wire harness W/H has a larger diameter, the smaller diameter tubular section  105  spreads its cross section in an ellipse shape and the pair of half cylindrical portions  104 A and  104 B also spread their cross sections in the ellipse shape with the tape T being wound around the outer peripheries of the portions  104 A and  104 B. Thus, if the pair of half cylindrical portions  104 A and  104 B do not keep a perfect circle in cross section, as shown in  FIG. 9A , the closing surface portions  103 A and  103 B coupled to proximal ends of the half cylindrical portions  104 A and  104 B are also pulled, so that a slit between opposed surfaces of the closing surface portions  103 A and  103 B is widened to cause a clearance C and so that an outside shape of the enlarging diameter tubular section  100  connected to the closing surface portions  103 A and  103 B is also deformed. In result, the vehicle body latch recess  102  provided in the outer peripheral surface of the enlarging diameter tubular section  100  is deformed in the ellipse shape in cross section, so that the recess  102  cannot contact with the through-hole in the vehicle body panel tightly. Under this condition, there is a possibility that water leakage will happen through the through-hole in the vehicle body panel. 
     On the other hand, in the case where the wire harness W/H has a smaller diameter, the half cylindrical portions  104 A and  104 B are contracted, so that the tape T is wound around the portions  104 A and  104 B in the ellipse shape in cross section, as shown in  FIG. 9B . This results in a state similar to the state shown in  FIG. 9A . The vehicle body latch recess  102  is deformed through the closing surface portions  103 A and  103 B. This will cause a possibility of water leakage. 
     Further, when the wire harness W/H on which the half cylindrical portions  104 A and  104 B are wound by the tape T is bent sharply, as shown in  FIG. 9C , the vehicle body latch recess  102  is deformed through the closing surface portions  103 A and  103 B, thereby causing the water leakage. 
     In addition, although the smaller diameter tubular section  105  extends in the enlarging diameter section  100 , as disclosed in Patent Document 1, even if the smaller diameter tubular section  105  protrudes outward from the smaller diameter tubular end of the enlarging diameter section  100 , the half cylindrical portions  104 A and  104 B protrude from the closing surface portions  103 A and  103 B to cover the outer peripheral surface of the wire harness W/H and the tape is wound around them, the above problem will happen. 
     Patent Document 1: JP 2007-135253 A 
     SUMMARY OF THE INVENTION 
     Problems that the Invention is to Solve 
     In view of the above problems, an object of the present invention is to provide a grommet that can enhance a waterproofing function by preventing a clearance from being caused in a connecting part between a smaller diameter tubular section of the grommet and a wire harness that passes the grommet in a close contact manner, and in particular to provide a grommet that can prevent a clearance from being caused in a connecting part between the grommet and a wire harness and to provide a grommet of which a vehicle body latch recess is not deformed, thereby maintaining a good sealing function, even if a wire harness that passes the grommet is bent sharply. 
     Means for Solving the Problems 
     In order to achieve the above object, the present invention is directed to a grommet that is mounted on a wire harness to be inserted into a through-hole in a vehicle body, is engaged with a vehicle body, and is made of an elastic material. The grommet includes: an inner tube for passing electrical cables in the wire harness in a close contact manner; an annular coupling section protruding from an outer peripheral surface of the inner tube; and an outer tube contiguous with an outer peripheral surface of the annular coupling section and disposed coaxially with the inner tube. The outer tube is adapted to couple the annular coupling section to a larger thickness portion of the outer tube and to couple a reducing diameter slant wall section to the larger thickness portion. The outer tube is provided in an outer peripheral surface at a boundary area between the larger thickness portion and the slant wall section with a vehicle body latch recess in an annular manner. The annular coupling section is formed into a smaller thickness. The annular coupling section is bent in a V-shaped configuration from an inner peripheral end coupled to the outer peripheral surface of the inner tube to an outer peripheral end coupled to an inner peripheral surface of the outer tube. 
     A projecting direction of the V-shaped configuration of the annular coupling section is opposite in direction to an extension of the slant wall section of the outer tube. If the annular coupling section protrudes toward the slant wall section, when the grommet is inserted into the through-hole in the vehicle body panel, the slant wall section is deflected inward and the annular coupling section that protrudes inward interferes with the deflection of the slant wall section. This will affect reduction in inserting force of the grommet. 
     Preferably, the V-shaped configuration of the annular coupling section is set to be an angle of 40 to 70 (forty to seventy) degrees. A length of the annular coupling section is set to be 1.5 to 4 (one and a half to four) times of a radial distance between an inner peripheral surface of the inner tube and an outer peripheral surface of the outer tube. A thickness of the annular coupling section is set to be less than thicknesses of the inner and outer tubes. 
     As described above, if the angle of the V-shaped configuration of the annular coupling section is set within the above range, it is possible to increase the length of the annular coupling section. When the inner tube is bent on account of the bending of the wire harness, the annular coupling section can increase an amount of absorbing the bending, so that transmission of the bending to the outer tube is cut off. If the annular coupling section has the smaller thickness, the annular coupling section can exert an absorbing action of the bending easily. 
     Since the annular coupling section that interconnects the outer tube and the inner tune through which the wire harness passes in the close contact manner is bent into the V-shaped configuration in the grommet of the present invention, the grommet can respond to the varying sizes in diameter of the wire harness merely by altering the bending angle of the annular coupling section, thereby permitting the tape to be wound around the inner tube, with the inner tube closely contacting with the wire harness. 
     Even if the inner tube is bent on account of the bending of the wire harness, the annular coupling section is contracted or expanded so as to follow the bending of the wire harness and the deformation of the inner tube can be absorbed in the annular coupling section before the bending of the inner tube is transmitted to the outer tube. Accordingly, it is possible to restrain and prevent any load such as a pulling action or a compressing action from affecting the outer tube. In result, it is possible to prevent the vehicle body latch recess provided in the outer peripheral surface of the outer tube from being deformed so as to maintain the recess in the circular shape and to prevent the recess from floating up. Thus, the vehicle body latch recess can contact with the peripheral edge around the through-hole in the vehicle body panel without shifting the recess from the through-hole. This can enhance the sealing effect and prevent the water leakage. 
     Preferably, in the grommet of the present invention, the annular coupling section protrudes from the outer peripheral surface of a longitudinal intermediate part between a pushing-in side and a drawing-out side of both ends of the inner tube. The larger thickness portion of the outer tube is contiguous with the outer peripheral end of the annular coupling section. An inner peripheral surface at a smaller diameter end side of the slant wall section of the outer tube is separated through a given clearance from the outer peripheral surface of the inner tube. A drawing-out side of the inner tube protrudes outward from the slant wall section. 
     The slant wall section may be provided on its smaller diameter end with a drawing-out distal end side tubular portion that extends in parallel to the axial direction of the inner tube and a separated clearance may be defined between the inner peripheral surface of the drawing-out distal end side tubular portion and the outer peripheral surface of the inner tube. 
     In the above grommet, the inner tube through which the wire harness passes in the close contact manner is separated at the drawing-out side of the wire harness through a great clearance from the outer tube provided with the vehicle body latch recess. 
     In the separated type grommet, even if the wire harness that is drawn out from the grommet and is arranged in the passenger room is bent sharply by an angle of 90 degrees or so to bend the inner tube, it is possible to prevent the bending of the inner tube from being transmitted to the outer tube directly. Since the inner tube is coupled through the annular coupling section to the outer tube at the longitudinal intermediate part from the drawing-out end side of the inner tube, the deformation of the inner tube can be absorbed in the annular coupling section and the deformation of the inner tube does not affect the vehicle body latch recess provided in the larger diameter end side of the outer tube. 
     Since the inner tube of the above grommet through which the wire harness passes in the close contact manner is not divided into half cylinders but the inner tube is formed into an integrated cylinder, it is possible for the inner tube to closely contact with the whole outer peripheral surface of the wire harness merely by increasing or decreasing the diameter of the inner tube in accordance with the varying sizes in diameter of the wire harness, thereby enhancing the sealing function of the connecting part between the grommet and the wire harness. 
     In the separated type grommet, a pushing rib protrudes from the annular coupling section toward an inner surface of the slant wall section. The pushing rib presses the slant wall section to transmit the pushing force to the slant wall. 
     When the grommet is inserted into the through-hole in the vehicle body panel, a working person holds the wire harness at the pushing-in side of the inner tube and pushes the wire harness into the through-hole. Since the inner tube is connected through the annular coupling section to the outer tube, the pushing force is hardly transmitted to the slant wall section at the drawing-out side of the outer tube. Consequently, the pushing rib is provided on the annular coupling section, the pushing rib presses the inner peripheral surface of the slant wall section at the drawing-out side, and the pushing force is transmitted through the pushing rib to the slant wall section. This can enhance workability in insertion of the grommet. It will be preferable to provide the pushing rib on the whole peripheral surface of the annular coupling section, since the pushing force to be transmitted to the slant wall section is uniformed. Preferably, a thickness of the pushing rib is set to be 2 to 4 (two to four) times of the thickness of the annular coupling section and is set to be larger than the thickness of the slant wall section. 
     The grommet of the present invention is not limited to the above separated type grommet. A coupled type grommet in which a smaller diameter end of the slant wall section is coupled through an annular coupling portion to the inner tube can be used in the present invention. 
     In the coupled type grommet, the inner tube is divided into a first inner tube member and a second inner tube member at a grommet drawing-out side and at a grommet pushing-in side respectively. A smaller diameter end of the slant wall section of the outer tube is coupled to the first inner tube member at the drawing-out side. The second inner tube member at the pushing-in side is coupled through the annular coupling section to the outer tube. The annular coupling section is provided with diametrically divided ends. The second inner tube member protrudes from the divided ends. The annular coupling section is bent in a V-shaped manner. 
     Even if the grommet of the present invention is either the separated type grommet or the coupled type grommet, the stepped longitudinal projecting ribs protrude from the outer peripheral surface of the slant wall section and are separated apart from one another in the peripheral direction, so that the contact area between the slant wall section and the through-hole can be reduced to lower the inserting force. Thus, the grommet can be inserted into the through-hole in the vehicle body panel by the one-motion operation of pushing the grommet from one side, thereby decreasing the inserting force. 
     EFFECTS OF THE INVENTION 
     As described above, according to the grommet of the present invention, the inner tube through which the wire harness passes in the close contact manner is coupled through the annular coupling section having the V-shaped configuration to the outer tube. Thus, even if the wire harness is bent sharply to bend the inner tube, the annular coupling section can absorb the deformation of the inner tube by changing the bending angle of the section and can absorb transmission of the deformation to the outer tube, thereby preventing the vehicle body latch recess from being deformed and floating up, and enhancing a waterproofing function. 
     The annular coupling section can follow the varying sizes in diameter of the wire harness by changing the angle of V-shaped configuration. Even in this case, the bending of the wire harness cannot affect the outer tube provided with the vehicle body latch recess and the waterproofing function can be obtained. 
    
    
     
       BRIEF EXPLANATION OF THE DRAWINGS 
         FIG. 1A  is a perspective view of a first embodiment of a grommet in accordance with the present invention taken from a drawing-out side.  FIG. 1B  is a perspective view of the grommet of the present invention taken from a pushing-in side. 
         FIG. 2  is a plan view of the grommet shown in  FIG. 1 , illustrating the grommet taken from the drawing-out side. 
         FIG. 3  is a longitudinal section view of the grommet taken along lines in  FIG. 2 . 
         FIG. 4  is a longitudinal section view of the grommet taken along lines IV-IV in  FIG. 3 . 
         FIG. 5  is a longitudinal section view of the grommet similar to  FIG. 3 , illustrating the grommet into which a wire harness is inserted and that is attached to a vehicle body. 
         FIG. 6A  is a schematic side elevation view of the grommet in the case where the wire harness is bent at the drawing-out side of the grommet.  FIG. 6B  is a schematic side elevation view of the grommet in the case where the wire harness is bent at the pushing-in side of the grommet. 
         FIG. 7  is a longitudinal section view of a second embodiment of the grommet in accordance with the present invention. 
         FIG. 8A  is a longitudinal section view of a prior art grommet.  FIG. 8B  is a longitudinal section view of the prior art grommet shown in  FIG. 8A , illustrating the grommet through which a wire harness passes. 
         FIGS. 9A to 9C  are explanatory views that illustrate problems in the prior art grommet. 
     
    
    
     EXPLANATION OF SIGNS 
     
         
           1 : grommet 
           2 : vehicle body panel 
           3 : through-hole 
           5 : inner tube 
           6 : annular coupling section 
           8 : outer tube 
           9 : larger thickness portion 
           10 : vehicle body latch recess 
           11 : slant wall section 
           15 : projecting ribs 
           18 : pushing rib 
       
    
     PREFERRED ASPECTS OF EMBODYING THE INVENTION 
     Referring now to the drawings, embodiments of a grommet in accordance with the present invention will be described below. 
       FIG. 1A  to  FIG. 6B  show a first embodiment of a grommet in accordance with the present invention. 
     As shown in  FIG. 5 , a grommet  1  is mounted on a wire harness W/H arranged from an engine room X in a motor vehicle via a through-hole  3  in a vehicle body panel  2  to a passenger room Y. The grommet  1  is engaged with a peripheral edge around the through-hole  3  to be attached to the vehicle body. The grommet  1  is a one-motion type grommet that is inserted into the through-hole  3  from an engine room X so as to be attached to the vehicle body. The one end of the grommet  1  defines a pushing-in side P 1  while the other end defines a drawing-out side P 2 . The grommet  1  is molded from rubber or elastomer. 
     The grommet  1  in the first embodiment is a separated type grommet in which a clearance is defined between a smaller diameter end of a slant wall section and an inner tube. 
     The grommet  1  includes an inner tube  5  having a smaller diameter and permitting a set of electrical cables in the wire harness W/H to pass in a close contact manner, an annular coupling section  6  that protrudes from an outer peripheral surface  5   a  on an intermediate part of the inner tube  5  between a pushing-in end  5 P 1  at the pushing-in side P 1  and a drawing-out end  5 P 2  at the drawing-out side P 2  in a longitudinal direction of the inner tube  5 , and an outer tube  8  having a larger diameter and contiguous with an outer peripheral surface of the annular coupling section  6 . 
     The outer tube  8  is coaxial with the inner tube  5  and is disposed through a space on an intermediate part of the inner tube  5  in its longitudinal direction. The inner tube  5  protrudes from opposite ends of the outer tube  8  at the pushing-in side P 1  and the drawing-out side P 2  in the longitudinal direction. 
     The outer tube  8  extends to the drawing-out side P 2  from a connecting part between the outer tube  8  and an outer peripheral surface of the annular coupling section  6 . A slant wall section  11  is contiguous with a larger thickness portion  9  provided on the connecting part and extends to the drawing-out side P 2  to reduce a diameter of the section  11  in the axial direction. An annular vehicle body latch recess  10  is provided in an outer peripheral surface on a boundary area between the larger thickness portion  9  and a larger diameter end of the slant wall section  11 . The slant wall section  11  is provided on its smaller diameter end with a drawing-out distal end side tubular portion  12  that extends in parallel to the axial direction of the inner tube  5 . 
     An annular clearance S ( FIG. 3 ) is defined between an inner peripheral surface of the drawing-out distal end side tubular portion  12  and the outer peripheral surface  5   a  of the inner tube  5  to separate the portion  12  apart from the inner tube  5 . That is, a smaller diameter end of the outer tube  8  surrounds the outer peripheral surface of the inner tube  5  through the annular clearance S and the drawing-out end  5 P 2  protrudes outward from the outer tube  8 . 
     As shown in  FIG. 3 , a radial distance d 1  of the annular clearance S is set to be ½ to 3/2 (one-half to three-halves) of a radius d 2  of the inner tube  5 . It is preferable in the present embodiment that the radial distance d 1  is ¾ (three quarters) of the radius d 2 . A length L 1  of the drawing-out distal end side tubular portion  12  that extends through the annular clearance S in parallel to the outer peripheral surface  5   a  of the inner tube  5  may be altered in accordance with a size of the grommet  1 . It is preferable in the present embodiment that the length L 1  is 5 to 15 mm (five to fifteen millimeters). 
     As shown in  FIG. 1B  and  FIG. 3 , the annular coupling section  6  that interconnects the outer tube  8  and inner tube  5  protrudes in a V-shaped configuration from an inner peripheral end  6   b  contiguous with the outer peripheral surface  5   a  of the inner tube  5  to the pushing-in side P 1 . An outer peripheral end  6   a  of the annular coupling section  6  is disposed at the pushing-in side P 1  over the inner peripheral end  6   b  and is contiguous with the larger thickness portion  9  of the outer tube  8 . 
     A projecting direction of the V-shaped configuration of the annular coupling section  6  is opposite in direction to an extension of the slant wall section  11  of the outer tube  8 , that is, the V-shaped configuration is directed to the pushing-in side P 1 . 
     An angle θ 1  (theta one) of the V-shaped configuration of the annular connecting section  6  is set to be 40 to 70 (forty to seventy) degrees. In the first embodiment, the angle θ 1  (theta one) is 60 (sixty) degrees. A length from the inner peripheral end  6   b  of the annular coupling section  6  to the outer peripheral end  6   a  is set to be 1.5 to 4 (one and a half to four) times of a radial distance between an inner peripheral surface of the inner tube  5  and an outer peripheral surface of the outer tube  8 . In the first embodiment, the length is 2.5 (two and a half) times of the radial distance. An opener cable and a feed water hose pass the grommet  1 . Accordingly, as shown in  FIG. 1B , the annular coupling section  6  is not bent in the V-shaped configuration at two opposite positions in a diametrical direction of the section  6  to form flat surfaces  6   e  and  6   f . The flat surfaces  6   e  and  6   f  are provided with through-apertures  31  and  32  through which the opener cable and feed water hose pass. 
     A thickness t 3  ( FIG. 3 ) of the annular coupling section  6  is set to be substantially equal to or less than a thickness t 4  ( FIG. 3 ) of the inner tube  5  so as to be deflectable. An angle θ 2  (theta two) of the annular coupling section  6  that is slant coupled to the outer peripheral surface  5   a  of the inner tube  5  is set to be 20 to 30 (twenty to thirty) degrees. Thus, the inner tube  5  and outer tube  8  are not interconnected to each other directly in the radial direction but interconnected to each other through the V-shaped annular coupling section  6 . Thus, when the inner tube  5  is deformed in connection with bending of the wire harness W/H, the annular coupling section  6  absorbs the deformation of the inner tube  5 , so that the deformation of the inner tube  5  is not transmitted directly to the outer tube  8 . This serves as a release portion. 
     As shown in  FIG. 3 , the annular coupling section  6  is provided on its inclined portion between the inner peripheral end  6   b  and a V-shaped projecting end  6   c  with a bent portion  6   d  that is bent toward the slant wall section  11 . A pushing rib  18  having a larger thickness protrudes from the bent portion  6   d  toward the slant wall section  11 . As shown in  FIG. 4 , the pushing rib  18  is continuous in its peripheral direction but it is divided at positions corresponding to guide inner tubes  28  and  29  for permitting an opener cable and a feed water hose to pass. 
     A thickness t 5  ( FIG. 3 ) of the pushing rib  18  is large enough to be 2 to 4 (two to four) times of the thickness t 3  of the annular coupling section  6 , is larger than the thickness t 1  of the slant wall section  11 , and is substantially the same as the thickness of the larger thickness portion  9 . 
     The reason why the pushing rib  18  is a larger thickness is ascribable to the fact that, when the grommet  1  is inserted into the through-hole  3  in the vehicle body panel  2 , a projecting end  18   a  of the pushing rib  18  contacts with the inner peripheral surface of the slant wall section  11  to permit the pushing force to be transmitted to the outer tube  8 . When the grommet  1  is attached to the vehicle body panel  2 , the projecting end  18   a  of the pushing rib  18  is disposed near the slant wall section  11  so that they can contact with each other. Thus, a sound-insulating space B ( FIG. 3 ) is defined among the pushing rib  18 , the inner tube  5 , the annular coupling section  6 , and the outer tube  8 . 
     As shown in  FIG. 3 , the pushing rib  18  protrudes slightly slant in its outer diametrical direction. The projecting end  18   a  is opposed to the smaller diameter end of the slant wall section  11  contiguous with the drawing-out distal end side tubular portion  12 . The drawing-out distal end side tubular portion  12  is provided with a stopper projection  12   a , which protrudes inward from the slant wall section  11 , at a side of the slant wall section  11  with which the pushing rib  18  contacts. Since the stopper projection  12   a  is provided on the drawing-out distal end side tubular portion  12 , it is possible to prevent the projecting end  18   a  of the pushing rib  18  from slipping down into the drawing-out distal end side tubular portion  12  and to surely bring the pushing rib  18  into contact with the slant wall section  11  so as to transmit the pushing force to the slant wall section  11 . 
     Furthermore, the slant wall section  11  is provided with an annular shallow recess in an inner surface from an outer diameter side, with which the projecting end  18   a  of the pushing rib  18  contacts, to the curved portion  11   c . Thus, the slant wall section  11  is provided with a smaller thickness portion  19  ( FIG. 5 ) having a smaller thickness t 6  ( FIG. 3 ). Since the slant wall section  11  is provided with the smaller thickness portion  19  from the curved portion  11   c  to the smaller diameter side, the smaller thickness portion  19  serves as a stress absorbing portion when the drawing-out distal end side tubular portion  12  is deformed on account of the bending of the wire harness. That is, a bending stress is concentrated in the smaller thickness portion  19 , so that the drawing-out distal end side tubular portion  12  is hard to transmit its deformation to the vehicle body latch recess  10 . The thickness t 6  of the smaller thickness portion  19  is smaller than the thickness t 3  of the annular coupling section  6 . 
     As shown in  FIG. 3 , the larger thickness portion  9  of the outer tube  8  protrudes slightly toward the pushing-in side P 1  from the connecting part between the larger thickness portion  9  and an outer peripheral end  6   a  of the annular coupling section  6 . A pushing-in side distal end surface  9   a  defines an orthogonal surface to an axis O of the inner tube  5 . The annular vehicle body latch recess  10  is provided on a boundary area between the larger thickness portion  9  and the slant wall section  11 . A distal end of a drawing-out side surface  10   b  that stands up from a bottom surface  10   a  of the vehicle body latch recess  10  is contiguous with a larger diameter end  11   a  of the slant wall section  11 . A smaller diameter end  11   b  of the slant wall section  11  is contiguous with the drawing-out distal end side tubular portion  12 . A curved portion  11   c  is provided between the larger diameter end  11   a  of the slant wall  11  and the smaller diameter end  11   b  so as to change an inclination angle of the outer peripheral surface of the slant wall section  11 . An inclination angle at the smaller diameter end side with respect to the curved portion  11   c  is set to be large while an inclination angle at the larger diameter end side with respect to the curved portion  11   c  is set to be small. 
     The slant wall section  11  is provided on the outer peripheral surface that changes the inclination angle with axially stepped projecting ribs  15  that extend from the larger diameter end  11   a  of the distal end of the drawing-out side surface  10   b  on the vehicle body latch recess  10  to the smaller diameter end  11   b  and are spaced apart from one another in the peripheral direction. Since these projecting ribs  15  have the same widths in the peripheral direction, the projecting ribs  15  that extend radially from the smaller diameter end to the larger diameter end have narrow distances between the adjacent ribs  15  at the smaller diameter end side in the peripheral direction and wide distances between the adjacent ribs  15  at the larger diameter end side. 
     As shown in  FIG. 3 , the inner peripheral surface of the outer tube  8  from the larger thickness portion  9  to the curved portion  11   c  of the slant wall section  11 , that is, from the larger thickness portion  9  to a larger diameter side end  11   e  defines a parallel surface  11   h  in parallel to the axial direction O. A thickness t 1  of a portion  11   d  from the curved portion  11   c  to the drawing-out distal end side tubular portion  12  is set to be small. A thickness t 2  of the drawing-out distal end side tubular portion  12  is set to be larger than the thickness t 1 . 
     As shown in  FIG. 4 , each projecting rib  15  that extends on the outer peripheral surface of the slant wall section  11  from the smaller diameter end of the slant wall section  11  to the larger diameter end is provided in an inner peripheral surface with a recess  15   h  that extends through a whole length of the projecting rib  15 . 
     Further, as shown in  FIGS. 1A and 1B , and  FIG. 2 , the slant wall section  11  is provided with axial grooves  15   k  and  15   i  on an outer surface at proximal ends of each projecting rib  15  and on each central parts between the adjacent projecting ribs  15 , respectively, thereby facilitating to deflect the slant wall section  11 . 
     As shown in  FIG. 1A , each projecting rib  15  provided on its larger diameter side of the slant wall section  11  is provided with a slant surface  15   c  that inclines the top surface  15   a  of the projecting rib  15  downward to the drawing-out side surface  10   b . Both side surfaces  15   d  and  15   e  of each projecting rib  15  at its distal end side across the slant surface  15   c  define slant surfaces  15   f  and  15   g  that approach to each other. That is, each projecting rib  15  is provided on its larger diameter end with the slant surfaces  15 ,  15   f , and  15   g  that are cut at three sides. Thus, since the distal end surface of each projecting rib  15  is cut at the three sides to form round corners and to eliminate edges, the projecting ribs  15  are not caught by the peripheral edge around the through-hole  3  in the vehicle body panel  2  when the peripheral edge around the through-hole  3  drops down into the vehicle body latch recess  10 . 
     As described above, the opener cable and feed water hose penetrate the grommet  1 . As shown in  FIG. 2 , the slant wall section  11  is provided with the through-apertures  24  and  25  so that the opener cable and feed water hose can pass the grommet  1 . As described above, the annular coupling section  6  is provided with the through-apertures  31  and  32 . Outer guide pipes  26  and  27  protrude outward from peripheral edges around the through-apertures  24  and  25 . The outer guide pipes  26  and  27  are provided on their distal ends with closing end portions  26   a  and  27   a . When using the outer guide pipes  26  and  27 , the closing end portions  26   a  and  27   a  are cut away to open the outer guide pipes  26  and  27 . 
     The smaller diameter inner tube  5 , through which the wire harness W/H passes, protrudes from the opposite ends of the outer tube  8  in the longitudinal direction. The inner tube  5  is provided on an inner peripheral surface of each protruding end portion over the outer tube  8  with three waterproofing lips  33  ( FIG. 3 ). 
     As shown in  FIG. 5 , since the through-hole  3  in the vehicle body panel  2  for receiving the grommet  1  is an aperture with a burr  3   b  that protrudes from the peripheral edge  3   a  around the through-hole  3  to the pushing-in side P 1 , the vehicle body latch recess  10  in the outer tube  8  has a configuration corresponding to the burr  3   b.    
     A process for attaching the wire harness W/H to the grommet  1  is carried out by inserting the electrical wires in the wire harness W/H while enlarging the inner peripheral surface of the inner tube  5  by a jig (not shown). After inserting the wire harness W/H into the inner tube  5 , the wire harness W/H drawn out from the opposite ends  5 P 1  and  5 P 2  of the inner tube  5  and the opposite ends  5 P 1  and  5 P 2  are secured to one another by winding adhesive tapes  40  around them. 
     Varying sizes in diameter of the wire harness W/H are absorbed in the annular coupling section  6 , so that the outer tube  8  connected through the annular coupling section  6  to the inner tube  5  is hardly subject to affections caused by the varying sizes. Accordingly, it is possible to maintain the outer diameter of the outer tube in a designed size. That is, since the annular coupling section  6  has a smaller thickness enough to be deformed and is formed into the V-shape, the annular coupling section  6  can respond to the varying sizes in diameter merely by changing the bending angle. The inner tube extends continuously. Both of the pushing-in end  5 P 1  and drawing-out end  5 P 2  are formed into annular shapes and are not divided into half members. Accordingly, the inner diameter of the inner tube  5  increases or decreases to follow the varying sizes of the wire harness W/H, thereby closely contacting the inner peripheral surface of the inner tube  5  with the outer peripheral surface of the wire harness W/H. Consequently, it is possible to enhance a sealing function by preventing a water immersion clearance from being caused between the inner tube  5  and the wire harness W/H. 
     As shown in  FIG. 5 , the grommet  1  mounted on the wire harness W/H is inserted into and attached to the through-hole  3  with the burr  3   b  in the vehicle body panel  2  that partitions a vehicle body into the engine room X and the passenger room Y. 
     A working process of inserting the grommet  1  into the through-hole  3  is carried out by inserting the drawing-out end  5 P 2  of the inner tube  5  into the through-hole  3  from the engine room X, and then pushing the grommet  1  into the through-hole  3  by a working person in the engine room X while holding the wire harness W/H with the grommet  1  by the working person. The grommet  1  is latched in the through-hole  3  by a one-motion operation in which a pushing-in action is effected at one time from the one side. 
     Specifically, since the portion lid of the smaller diameter side of the slant wall section  11  of the outer tube  8  is smaller than the inner diameter of the through-hole  3 , the grommet  1  can be readily inserted into the through-hole  3 . When the curved portion  11   c  of the slant wall section  11  reaches the inner peripheral surface  3   a  of the through-hole  3 , the stepped projecting ribs  15  of the slant wall section  11  contact with the inner peripheral surface  3   a , thereby causing an inserting resistance. Then, the outer tube  8  cannot be further pushed into the through-hole  3  easily from the inner peripheral surface  3   a.    
     However, if the working person holds and pushes the wire harness W/H to be drawn out from the pushing-in side P 1  of the inner tube  5 , the inner tube  5  that closely contacts with the wire harness W/H is advanced to the drawing-out side P 2  in the drawing-out direction. The pushing rib  18  of the annular coupling section  6  connected to the inner tube  5  is also advanced to the inner surface of the slant wall section  11  of the outer tube  8  by the movement of the inner tube  5 , and the projecting end  18   a  of the pushing rib  18  bumps onto the inner peripheral surface of the slant wall section  11 . Thus, since the slant wall section  11  is pushed and moved forward by the pushing rib  18 , the outer tube  8  with the slant wall section  11  passes through the through-hole  3  to the passenger room Y. 
     The pushing rib  18  presses the slant wall section  11  and the distal ends of the stepped projecting ribs  15  reach the inner peripheral surface  3   a  of the through-hole  3 . Since each stepped projecting rib  15  is provided on the distal end with slant surfaces  15   c ,  15   f , and  15   g  in three cut-away sides, the inner peripheral surface  3   a  of the through-hole  3  and the burr  3   b  fall down into the vehicle body latch recess  10  as if the stepped projecting ribs  15  fall down into the through-hole  3 , and the grommet  1  can be secured to the vehicle body panel  2 . 
     As described above, after the grommet  1  is secured to the vehicle body panel  2 , as shown in  FIG. 6A , the wire harness W/H drawn out into the passenger room Y is sharply bent downward (or upward, rightward, or leftward) by an angle of 90 (ninety) degrees in many cases. 
     If the wire harness W/H is bent downward by the angle of 90 degrees, the wire harness W/H can closely contact with and pass through the inner tube  5 , the inner tube  5  secured to the wire harness W/H by the adhesive tapes  40  follows the bending angle of the wire harness W/H, and the inner tube  5  is bent downward at the drawing-out end  5 P 2 . 
     In this case, even if the drawing-out end  5 P 2  is bent downward in the grommet  1  of the present invention, the outer tube  8  is not coupled to the inner tube  5  at the drawing-out end  5 P 2  and the great clearance S exists between the drawing-out distal end side tubular portion  12  of the outer tube  8  and the inner tube  5 . Thus, since the inner tube  5  is merely bent in the clearance S between the inner tube  5  and the outer tube  8 , the outer tube  8  is not bent at the drawing-out side P 2 . 
     In the case where the wire harness W/H is bent sharply by the angle of 90 degrees or so at the pushing-in side P 1 , the inner tube  5  is greatly bent by the bending of the wire harness W/H, the bending will be transmitted through the annular coupling section  6  connected to the inner tube  5  to the outer tube  8 . Even in this case, the V-shaped thin annular coupling section  6  will absorb the deformation of the inner tube  5 . 
     On the other hand, as shown in  FIG. 6B , if the wire harness W/H is bent at the pushing-in side P 1  in the engine room X, it is possible for the annular coupling section  6  to absorb the bending of the wire harness W/H, thereby surely holding the vehicle body latch recess  10  in the through-hole  3 . Thus, it is possible to prevent the vehicle body latch recess  10  from floating up on account of the bending affection and to prevent the sealing function from being lowered. 
     Even in either case shown in  FIG. 6A  or  FIG. 6B , since the annular coupling section  6  can absorb the bending of the inner tube  5 , it is possible to maintain the vehicle body latch recess  10  in the circular state, to hold the whole periphery of the bottom surface of the vehicle body latch recess  10  in the inner peripheral surface of the through-hole  3  in a close contact manner, and to surely prevent water from entering the passenger room Y from the engine room X. 
       FIG. 7  shows a second embodiment of a grommet  1 - 1  in accordance with the present invention. 
     The grommet  1 - 1  is a coupled type grommet in which a smaller diameter end of a slant wall section at a drawing-out side P 2  is coupled to an inner tube, as is the case with the prior art grommet  100  shown in  FIG. 8A . 
     In the grommet  1 - 1  in the second embodiment, an inner tube is divided into a first inner tube member  50  at a grommet drawing-out side P 2  and a second inner tube member  55  at a grommet pushing-in side P 1 . A smaller diameter end of a slant wall section  51  of an outer tube  8  is coupled through an annular coupling portion  53  to the first inner tube member  50  at the drawing-out side P 2 . The second inner tube member  55  at the pushing-in side P 1  is coupled through a V-shaped annular coupling section  56  ( 56 A and  56 B) to a larger thickness portion  54  of the outer tube  8 . 
     The annular coupling section  56  is divided in a diametrically direction into a pair of substantially half circular annular coupling parts  56 A and  56 B. These annular coupling parts  56 A and  56 B correspond to the annular coupling section  6  in the first embodiment. The annular coupling parts  56 A and  56 B have smaller thicknesses, as is the case with the annular coupling section  6 , and bending angles θ 1  (theta one). 
     An end of the second inner tube member  55  is provided with half circular grooves and half cylindrical portions  55 A and  55 B protrude from peripheral edges of the grooves to oppose to each other. 
     A guide pipe  58  for a feed water hose and a guide pipe for an opener cable (not shown) protrude from the annular coupling section  56 . 
     Even if the wire harness is bent and the second inner tube member  55  in the grommet  1 - 1  constructed above is bent on account of the bending of the wire harness, since the annular coupling section  56  connected to the second inner tube member  55  is bent in the V-shape, the annular coupling section  56  can absorb the bending of the second inner tube member  55  by changing the bending shape of the annular coupling section  56 . Accordingly, it is possible to prevent the bending of the second inner tube member  55  from being transmitted to the outer tube  8  provided with the vehicle body latch recess  10 , thereby preventing the vehicle body latch recess  10  from being deformed and obtaining a good sealing function.