AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION NAME OF APPLICANT(S):: Sumitomo Wiring Systems, Ltd. ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 1 Nicholson Street, Melbourne, 3000, Australia INVENTION TITLE: Grommet The following statement is a full description of this invention, including the best method of performing it known to me/us: 5102 P.OPER\MRF\Spc Icanons2m9242 Mxospcc.acd 26 doc-25,hx/2hn [Detailed Description of the Invention] [0001] [Technical Field to which the Invention Belongs] The present invention relates to a grommet, and more 5 particularly, to a grommet that is assembled to a wire harness being arranged on an automobile, mounted in a through-hole of an automotive body panel, and achieves protection of the wire harness in that portion of the through-hole, through which insertion is effected. The 10 grommet may effect water tightness and dust-tightness. [0002] [Background] A grommet is mounted on a wire harness that is extended to an automobile interior from an engine room of an 15 automobile, and the grommet is mounted to a through-hole of an automotive body panel that partitions the engine room and the automobile interior from each other, whereby protection of the wire harness passing through the through-hole, water tightness, dust-tightness, and sound insulation of the 20 automobile interior from the engine room are achieved. [0003] It is demanded of a grommet of this kind that an insertion force be reduced when the grommet is mounted into a through-hole of an automotive body panel and a shape 25 retaining force be high after mounting. The applicant of the present application has proposed a grommet 1 of this kind shown in Fig. 6 of JP-A-2002-233035. The grommet 1 is pulled obliquely to be mounted on an automotive body panel and preferably adopted in the case 30 where a wire harness cannot be arranged in a direction perpendicular to a through-hole because an interference member is present in the vicinity of the through-hole of the automotive body panel. [0004] 35 The grommet 1 comprises a small-diameter cylindrical portion 2 and an enlarged-diameter cylindrical portion 4 contiguous to the small-diameter cylindrical portion 2, an annular latch recess 5b is provided on an outer peripheral surface of the enlarged-diameter cylindrical portion 4 40 toward a large-diameter opening end to be interposed between an inclined wall 5a and a tip end side vertical wall 5c, an axis of the small-diameter cylindrical portion 2 and an axis of the enlarged-diameter cylindrical portion 4 are bent, and an amount, by which the inclined wall 5a projects 45 from the outer peripheral surface of the enlarged 2 P:OPER\MRF\Spccifrcions\2(K.AI 241X peI pc inend 216 doc-25IN2(I19 diameter cylindrical portion, is such that an inclined wall 5a-2 on a bent side of the small-diameter cylindrical portion 2 projects a small amount and an inclined wall 5a-1 on an opposite side projects a large amount. 5 The grommet 1 is pulled in a direction Y and latched on an automotive body panel by fitting a peripheral edge of a through-hole provided on the automotive body panel onto the latch recess 5b of the grommet 1. [0005] 10 [Patent Document 1] JP-A-2002-233035 [0006] With the grommet 1, however, since the enlarged diameter cylindrical portion 4 is hard to deflect in a 15 direction of diameter reduction when the grommet 1 is inserted into the through-hole of the automotive body panel, there is involved a problem that an insertion force required at the time of insertion of the grommet 1 cannot be adequately reduced. 20 [0007] It is desirable to reduce an insertion force required when a grommet is obliquely inserted and to give a sufficient retaining force to a grommet latched on an automotive body panel. 25 [0008] The invention provides a grommet comprising a small diameter cylindrical portion and an enlarged-diameter cylindrical portion contiguous to the small-diameter cylindrical portion, the enlarged-diameter cylindrical 30 portion being provided on a large-diameter side outer peripheral surface thereof with a latch recess, the grommet armoring a wire harness, passing through a through-hole of an automotive body panel, having the latch recess fitted on a peripheral edge of the through-hole, and being mounted on 35 the automotive body panel, wherein an axis of the small diameter cylindrical portion and an axis of the enlarged diameter cylindrical portion are bent, grooves are provided at circumferential spaces on an inner peripheral surface or an outer peripheral surface of the enlarged- diameter 40 cylindrical portion on a side opposed to the bent side of the small-diameter cylindrical portion, and no grooves are provided on the inner peripheral surface and the outer peripheral surface of the enlarged-diameter cylindrical portion on the bent side. 45 [0009] With the above construction, a pulling force on the grommet may be hard to be transmitted to the tip end of the reduced-diameter side wall on a side opposed to the bent 3 P:\OPER\M p c Nos M . nd 2 doc-2510r/2-19 side, but the grooves provided on the inner peripheral surface of the enlarged-diameter cylindrical portion on a side opposed to the bent side may facilitate deflection in the direction of diameter reduction, so that the peripheral 5 edge of the through-hole of the automotive body panel becomes easy to get over the tip end of the reduced diameter side wall and so a small insertion force makes it possible to have the peripheral edge of the through-hole falling onto the latch recess. Also, no grooves are provided 10 on the inner peripheral surface of the enlarged-diameter cylindrical portion on the bent side, but the pulling force on the grommet may be easy to be transmitted thereto, so that an insertion force is not increased in having the peripheral edge of the through-hole falling onto the latch 15 recess on the bent side. Thereby, it is possible to reduce an insertion force when the grommet is mounted onto the through-hole of the automotive body panel. Also, even when a force opposed to the direction of pulling is applied on the grommet, the enlarged-diameter 20 cylindrical portion on the bent side, to which a force may be easily transmitted, is hard to deflect, so that the peripheral edge of the through-hole is not easily disengaged from the latch recess. In the preferred embodiments of the invention, the bent 25 side is a side on which the small-diameter cylindrical portion and the enlarged-diameter cylindrical portion are closest to each other. [0010] Preferably, the grooves are not provided on the inner 30 peripheral surface and the outer peripheral surface of the enlarged-diameter cylindrical portion in the range of at least 600 about the axis of the enlarged-diameter cylindrical portion on the bent side. The reason for this is that in the case where the 35 grooves are provided on the inner peripheral surface or the outer peripheral surface of the enlarged-diameter cylindrical portion in the range of at least 600 on the bent side, deflection is liable to occur on the bent side in the direction of diameter reduction, so that when a force 40 opposed to the direction of pulling is applied on the grommet, the enlarged-diameter cylindrical portion on the bent side, to which a force is easy to be transmitted, deflects and a retaining force of the grommet is decreased. (0011] 45 Preferably, an outside diameter of a tip end of a 4 reduced-diameter side wall out. of both side walls that interpose a bottom surface of latch recess is partially varied, and an outside diameter of the tip end of the reduced-diameter side wall disposed on the bent side of the small-diameter cylindrical portion is larger by 0.5 to 3.0 % than an outside diameter of the tip end of the reduced diameter side wall disposed on a side opposed to the bent side. With the above construction, even when a force opposed to the direction of pulling is applied on the grommet, the peripheral edge of the through-hole is not easily disengaged from the latch recess since an outside diameter of the tip end of the reduced-diameter side wall disposed on the bent side, to which a force is easy to be transmitted, is enlarged, so that a retaining force of the grommet can be enhanced. [0012] Preferably, an outside diameter of the tip end of the reduced-diameter side wall is enlarged in the range of at least 600 about the axis of the enlarged-diameter cylindrical portion on the bent side. The reason for this is that when a range, in which an outside diameter of the tip end of the reduced-diameter side wall is enlarged, is smaller than 600, it is not possible to adequately produce an effect of increasing a retaining force due to enlargement of an outside diameter of the tip end of the reduced-diameter side wall. [0013] [Mode for Carrying Out the Invention] An embodiment of the invention will be described below with reference to the drawings. Figs. 1 to 3 show an embodiment of the invention. A grommet 10 is integrally molded from rubber or elastomer and comprises a small-diameter cylindrical portion 12, an enlarged-diameter cylindrical portion 14 contiguous to the -small-diameter cylindrical portion 12 and having an axis X bent relative to an axis R of the small diameter cylindrical portion 12, and a latch recess 15 provided annularly on an outer peripheral surface of the enlarged-diameter cylindrical portion 14 toward a large diameter opening end. Also, a paddle-shaped triangular piece 13 contiguous to an outer peripheral surface of the small-diameter cylindrical portion 12 and the outer peripheral surface of the enlarged-diameter cylindrical portion 14 is provided on a bent side, on which the outer peripheral surface of the small-diameter cylindrical portion 12 and the outer peripheral surface of the enlarged-diameter cylindrical portion 14 are closest to 5 each other. [0014] As shown in Figs. 1 and 2, grooves 20 are provided circumferentially at spaces on an inner peripheral surface of the enlarged-diameter cylindrical portion 14. The grooves 20 are provided to extend to the vicinity of the latch recess 15 from a substantially central position of the enlarged-diameter cylindrical portion 14 in an axial direction. Also, the grooves 20 are provided not on a bent side of the enlarged-diameter cylindrical portion 14 but only on the inner peripheral surface thereof on a side opposed to the bent side. Detailedly, as shown in Fig. 1, grooves 20A are provided on both right and left sides of the axis X, a groove 20B is provided above the axis X, and grooves 20C are provided one by one between the grooves 20A and the groove 20B. [0015] The small-diameter cylindrical portion 12 comprises a first small-diameter cylindrical portion 12a, an enlarged diameter step portion 12b contiguous to the first small diameter cylindrical portion 12a, and a second small diameter cylindrical portion 12c contiguous to the enlarged-diameter step portion 12b, and three annular ridges 12d are provided on an inner peripheral surface of the first small-diameter cylindrical portion 12a. [0016] The latch recess 15 provided annularly on a large diameter side of the enlarged-diameter cylindrical portion 14 comprises a vertical wall 15a projecting toward the large-diameter side, and a reduced-diameter side wall 15c opposed thereto with a bottom surface 15b therebetween. An outer peripheral surface of the reduced-diameter side wall 15c is inclined to be increased in diameter toward the small-diameter cylindrical portion 12, and the outer peripheral surface of the enlarged-diameter cylindrical portion 14 is inclined to be reduced in diameter from a tip end 15d of the reduced-diameter side wall 15c on a side of the small-diameter cylindrical portion 12, to a position contiguous to the small-diameter cylindrical portion 12. A seal lip 15a-2 is provided annularly on an outer diametrical end of a side surface 15a-1 of the vertical wall 15a to project in a direction of the axis X of the grommet 10. [0017] Subsequently, an explanation will be given to the operation of mounting the grommet 10 on an automotive body panel P. First, a wire harness W/H is inserted into hollow 6 portions of the small-diameter cylindrical portion 12 and the enlarged-diameter cylindrical portion 14 of the grommet 10, and the first small-diameter cylindrical portion 12a and the wire harness W/H are fixed together by means of tape T. When the wire harness W/H is to be arranged on an automotive body, as shown in Fig. 3 (A) , it is inserted through a. through-hole H of the automotive body panel P from a side of the small-diameter cylindrical portion 12 of the grommet 10. Little pulling force is required until a peripheral edge of the through-hole H reaches that portion of the enlarged-diameter -cylindrical portion 14, of which an outside diameter becomes equal to an inner diameter of the through-hole H, and when the peripheral edge of the through-hole H abuts against the enlarged-diameter cylindrical portion 14, a feeling of moderation is generated in a worker. [0018] The worker pulls the grommet 10 obliquely from a position of such moderation as shown in Fig. 3(B), that is, pulls the grommet 10 toward a bent side of the small diameter cylindrical portion 12, whereby the peripheral edge of the through-hole H deflects the tip end 15d of the reduced-diameter side wall 15c in a direction of diameter reduction to pass over the tip end 15d of the reduced diameter side wall 15c and falls onto the bottom surface 15b as shown in Fig. 3(C) to be latched and interposed between the reduced-diameter side wall 15c and the vertical wall 15a. At this time, an inner peripheral surface of the automotive body panel P abuts against the seal lip 15a-2 of the vertical wall 15a, so that water tightness is ensured. [00191 With the above construction, the pulling force on the grommet 10 is hard to be transmitted to the tip end 15d of the reduced-diameter side wall 15c on a side opposed to the bent side, but the grooves 20 are provided on the inner peripheral surface of the enlarged-diameter cylindrical portion 14 on a side opposed to the bent side to facilitate deflection in the direction of diameter reduction, so that the peripheral edge of the through-hole H becomes easy to get over the tip end 15d of the reduced-diameter side wall 15c and so a small insertion force makes it possible to have the peripheral edge of the through-hole H falling onto the bottom surface 15b. Also, any grooves 20 are not provided on the inner peripheral surface of the enlarged diameter cylindrical portion 14 on the bent side, but the pulling force on the grommet 10 is easy to be transmitted thereto, so that an' insertion force is not increased in 7 having the peripheral edge of the through-hole H falling onto the bottom surface 15b on the bent side. Thereby, a small insertion force makes it possible to easily have the grommet 10 mounted onto the through-hole H of the automotive body panel. Also, even when a force opposed to the direction of pulling is applied on the grommet 10, the enlarged-diameter cylindrical portion 14 on the bent side, to which a force is easy to be transmitted, is hard to deflect, so that the peripheral edge of the through-hole H is not easily disengaged from the bottom surface 15b. In addition, the grooves provided on the inner peripheral surface of the enlarged-diameter cylindrical portion may be provided on the outer peripheral surface of the enlarged-diameter cylindrical portion. [00201 Figs. 4 and 5 show a second embodiment of the invention. A grommet 10' according to the second embodiment is of substantially the same shape as that of the grommet 10 according to the first embodiment except that a tip end 15d' of a reduced-diameter side wall 15c' is partially varied in outside diameter. Concretely, a tip end 15d-1' of the reduced-diameter side wall 15c' extending 450 on both right and left sides from a bent side of the tip end 15d' of the reduced-diameter side wall 15c' has an outside diameter of 76.0 mm (hl = 38.0 mm) about an axis X, and a remaining tip end 15d-3' with tip ends 15d-2' extending in the range of 100 on both right and left sides from both ends of the tip end 15d-1' and interposed therebetween has an outside diameter of 75.0 mm (h2 = 37.5 mm) about the axis X. That is, the outside diameter of the tip end 15d 1' of the reduced-diameter side wall 15c' is larger about 1.3 % than that of the tip end 15d-3'. Also, a bottom surface 15b' has a uniform diameter over an entire circumference, and the outside diameter of the tip end 15d 1' on the bent side is larger than that of the tip end 15d 3' on a side opposed to the bent side so that a bottom surface 15b-1' on the bent side is made deeper than a bottom surface 15b-2' on the side opposed to the bent side. Also, the tip ends 15d-2' interposed between the tip end 15d-1' and the tip end 15d-3' assume a circular arc that connects between an end of the tip end 15d-1' and an end of the tip end 15d-3', and so correct a difference in outside diameter between the tip end 15d-1' and the tip end 15d-3'. [0021] With the above construction, the tip end 15d-1' of 8 P 0PER\M\pecificaions()9%I2433KIP spccimnd 21 doc-25 2M -9 the reduced-diameter side wall 15c' on the bent side, to which a pulling force is easy to be transmitted, is made large in outside diameter, so that the peripheral edge of the through-hole H is not easily disengaged from the bottom 5 surface 15b' and a retaining force of the grommet 10' can be enhanced. In addition, since the remaining structure is the same as that according to the first embodiment, an explanation therefore is omitted. 10 [0022] As apparent from the above description, the grooves are provided on the inner peripheral surface of the enlarged diameter cylindrical portion on the side opposed to the bent side of the small-diameter cylindrical portion and the 15 enlarged-diameter cylindrical portion to facilitate deflection in the direction of diameter reduction, so that a peripheral edge of a through-hole of an automotive body panel becomes easy to get over the tip end of the reduced diameter side wall and so an insertion force can be reduced 20 when the grommet is mounted onto the through-hole of the automotive body panel. Also, any grooves are not provided on the inner peripheral surface of the enlarged-diameter cylindrical portion on the bent side, but a pulling force on the grommet is easy to be transmit thereto, so that an 25 insertion force is not increased in having the peripheral edge of the through-hole falling onto the latch recess on the bent side. Also, even when a force opposed to the direction of pulling is applied on the grommet, the enlarged-diameter 30 cylindrical portion on the bent side, to which a force is easy to be transmitted, is hard to deflect, so that the peripheral edge of the through-hole is not easily disengaged from the latch recess and it is possible to give a sufficient retaining force to the grommet. 35 [0023] Also, when an outside diameter of the tip end of the reduced-diameter side wall on the bent side is made larger than that of the tip end of the reduced-diameter side wall on the side opposed to the bent side, the peripheral edge of 40 the through-hole is not easily disengaged from the latch recess on the bent side and a retaining force of the grommet can be enhanced. [Brief Description of the Drawings] [Fig. 1] Fig. 1 is a front view showing a grommet according 45 to a first embodiment of the invention. [Fig. 2] Fig. 2(A) is a view showing a cross section of the 9 grommet taken along the line A-A and Fig. 2(B) is a view showing a cross section of the grommet taken along the line B-B. [Fig. 3] Fig. 3 is a view illustrating a way to mount a grommet. [Fig. 4] Fig. 4 is a back view showing a grommet according to a second embodiment of the invention. [Fig. 5] Fig. 5 is a view showing a cross section of the grommet taken along the line C-C. [Fig. 6] Fig. 6 is a view showing a conventional example. [Description of Reference Numerals and Signs] 10: grommet 12: small-diameter cylindrical portion 14: enlarged-diameter cylindrical portion 15: latch recess 15b: bottom surface 15c: reduced-diameter side wall 15d: tip end of reduced-diameter side wall 20: grooves W/H: wire harness Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in Australia. 10