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, elbourne, 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 C:\NRNorbI\DCC\GAV\2719842 I.DOC-1 l,2/2010 - A [Detailed Description of the Invention] (0001] [Technical Field to which the Invention Belongs] The present invention relates to a grommet, and, in 5 preferred embodiments thereof, to a grommet which is assembled to a wire harness to be arranged in an automobile, and mounted to a through hole in a vehicle body panel so as to attain protection of the wire harness in a part passed through the through hole, and to obtain 10 waterproof and dustproof performances. [0002] (Background] Generally, a wire harness to be arranged in an automobile from an engine room to a vehicle room is 15 provided with a grommet, and the grommet is fitted in a through hole formed in a vehicle body panel which partitions the vehicle room from the engine room, thereby to attain protection of the wire harness passed through the through hole, and also to obtain waterproof, dustproof and 20 soundproof performances from the engine room to the vehicle room. (0003] In many cases, the grommet of this type is pulled straightly in a direction perpendicular to the through hole 25 in the vehicle body panel for the purpose of inserting and engaging it into the through hole. However, in case where an obstacle is present near the through hole in the vehicle body panel, the grommet is unable to be straightly pulled. As the grommet in the above described case, the 30 applicant has already provided a grommet 1 as shown in Fig. 4, in Japanese Patent Publication No. JP-A-2002 233035. (0004] The above described grommet 1 has a small diameter 35 tubular part 2 and an enlarged diameter tubular part 4 continued from the small diameter tubular part 2. The enlarged diameter tubular part 4 is provided, at its large diameter side, with an annular groove 5b to be engaged with a vehicle body which is interposed between an inclined wall 40 Sa and a vertical wall Sc. An axis of the above described small diameter tubular part 2 and an axis of the enlarged diameter tubular part 4 are bent with respect to each other, and at the same time, the inclined wall Sa protruded from an outer peripheral face of the enlarged diameter 45 tubular part is so designed that the amount of protrusion is smaller in the inclined wall Sa-2 at a bent side of the small diameter tubular part 2, while the amount of protrusion is larger in the inclined wall 5a-1 at the opposite side.
C:\NRPorb\DCCGAV\271942 .DOC-I12 2IO -2 By pulling the above described grommet 1 in a direction of an arrow mark Y, a circumferential edge of the through hole provided in the vehicle body panel is fitted into the groove 5b to be engaged with the vehicle body, 5 thereby enabling the grommet 1 to be engaged with the vehicle body panel. [0005] However, there has been a problem that in case where a force in a direction opposite to the direction Y is exerted 10 on the grommet 1 after the grommet 1 has been engaged with the vehicle body panel, the groove 5b-2 to be engaged with the vehicle body at the bent side where the force is likely to be transmitted will be disengaged from the circumferential edge of the through hole, because the 15 groove 5b to be engaged with the vehicle body has a constant depth in its entire circumference, and the grommet 1 will be inevitably detached from the vehicle body panel. It has been considered that the groove 5b to be engaged with the vehicle body may be made deeper so that 20 the grommet 1 may not be detached by the force in the direction opposite to the direction Y. In this case, however, the amount of protrusion of the inclined wall 5a becomes large, and a pulling force will not be easily transmitted to the side opposite to the bent side. Thus, 25 there has been a problem that an insertion force required for a work for inserting the grommet is increased, which deteriorates workability. [0006] [Prior Art] 30 The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from 35 it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates. [0007] [Summary of the Invention] 40 According to the invention, there is provided a grommet comprising an enlarged diameter tubular part provided, at its large diameter side, with an annular recess to be engaged with a vehicle body, and a small diameter tubular part continued in a bent form from a 45 reduced diameter end of said enlarged diameter tubular part, wherein a wire harness is inserted into said small diameter tubular part and said enlarged diameter tubular part to be attached thereto, said grommet at a side of the small diameter tubular part being configured to be 50 pulled and inserted into a through hole in a vehicle body panel thereby to engage said annular recess with said through hole, C:\NRfonb\DCCOGA\2719842I.DOC-I2/22010 -3 wherein said annular recess has side walls interposing a bottom face, and the side wall at the reduced diameter side of both the side walls is varied in a circumferential direction in its height from the 5 bottom face, so that the height of the side wall at the reduced diameter side is made larger at a bent side of said small diameter tubular part than at the other side opposite to the bent side, thereby increasing an engaging force of the grommet when engaged with the vehicle body. 10 [0008] Preferred embodiments of the invention have been made in view of the above described problems, and provide a grommet in which an insertion force required for inserting the grommet diagonally will be decreased, and an engaging 15 force for engaging the grommet with a vehicle body panel will be increased. [0009] According to the above described structure, the pulling force of the grommet is not likely to be 20 transmitted to the annular recess at the side opposite to the bent side. However, since the height of the side wall at the reduced diameter side from the bottom face is made smaller at the side opposite to the bent side, the circumferential edge of the through hole may be able to 25 ride easily across the tip end of the side wall at the reduced diameter side. Accordingly, it may be possible to drop the circumferential edge of the through hole into the annular recess with a small insertion force. Moreover, although the height of the side wall at the 30 reduced diameter side from the bottom face is made larger at the bent side than at the side opposite to the bent side, a large insertion force need not be required for dropping the circumferential edge of the through hole into the annular recess at the bent side, because the pulling 35 force of the grommet is likely to be transmitted to the side wall at the bent side. As a result, the grommet can be easily mountable to the through hole in the vehicle body panel with the small insertion force. [0010] 40 Further, even though a force in a direction opposite to the pulling direction has been exerted on the grommet, the circumferential edge of the through hole may be not easily detached from the annular recess, because the height of the side wall at the bent side where the force is likely 45 to be transmitted is made larger. In the preferred embodiments of the invention, the bent side is a side where the small diameter tubular part and the enlarged diameter tubular part are closest in position to each other. 50 [0011] It is preferable that a diameter of a tip end of the side wall of the aforesaid annular recess at the reduced C:\NRPonb\DCCGA V2719842 . DOC-12O2/2010 -4 diameter side be 0.5 to 3.0% larger at the bent side where the height is larger than at the opposite side where the height is smaller. In case where the difference is smaller than 0.5%, it 5 may be impossible to fully obtain an advantage of increasing the engaging force by making the side wall at the reduced diameter side higher, and the circumferential edge of the through hole may tend to be detached from the annular recess at the bent side, when the force in a 10 direction opposite to the pulling direction has been exerted on the grommet. On the other hand, in case where the difference is larger than 3.0%, the side wall at the bent side becomes undesirably high, and the insertion force for engaging the annular recess at the bent side with the 15 circumferential edge of the through hole becomes large. [00121 It is preferable that the side wall of the aforesaid annular recess at the reduced diameter side be made higher at the bent side in a range of 60 to 180 degrees around an 20 axis of the aforesaid enlarged diameter tubular part. In the case where the range is smaller than 60 degrees, it may be impossible to fully obtain an advantage of increasing the engaging force by making the side wall at the reduced diameter side at the bent side higher, and the 25 circumferential edge of the through hole may tend to be detached from the annular recess at the bent side, when the force in a direction opposite to the pulling direction has been exerted on the grommet. On the other hand, in the case where the range is larger than 180 degree, the outer 30 diameter of the tip end of the side wall at the side opposite to the bent side becomes undesirably large, and it may be impossible to decrease the insertion force of the grommet. [0013] 35 [Best Mode for Carrying Out the Invention] Now, an embodiment of the invention will be described referring to the drawings. Figs. 1 to 3 show the embodiment of the invention. A grommet 10 is integrally formed of rubber or 40 elastomer, and includes a small diameter tubular part 12, an enlarged diameter tubular part 14 continued from the small diameter tubular part 12 and having an axis X which is bent with respect to an axis R of the small diameter tubular part 12, and an annular recess 15 which is formed 45 on an outer peripheral face of the enlarged diameter tubular part 14 - at a large diameter side thereof. Moreover, a triangular piece 13 in a paddle shape continued to both an outer peripheral face of the small diameter tubular part 12 and the outer peripheral face of the enlarged diameter tubular part 14 is provided at a bent side where the outer peripheral face of the small diameter tubular part 12 and that of the enlarged diameter tubular part 14 are closest in position to each other. [0014] The small diameter tubular part 12 includes a first small diameter tubular portion 12a, an enlarged diameter stepped portion 12b continued from the first diameter tubular portion 12a, and a second small diameter tubular portion 12c continued from the enlarged diameter stepped portion 12b. The first small diameter tubular portion 12a is provided, on its inner peripheral face, with three annular ribs 12d. [0015] The latch recess 15 provided at the large diameter side of the enlarged diameter tubular part 14 is defined between a vertical wall 15c projected at the large diameter side and a side wall 15a at a reduced diameter side which is opposed to the vertical wall 15c interposing a bottom face 15b. An outer peripheral face of the side wall 15a at the reduced diameter side is inclined so as to be enlarged in diameter toward the small diameter tubular part 12, and then, inclined from a tip end 15d of the side wall at the reduced diameter side, which is an edge of the small diameter tubular part 12 of the side wall 15a at the reduced diameter side, up to a position to be connected to the small diameter tubular part 12 so as to reduce the diameter of the outer peripheral face of the enlarged diameter tubular part 14. An annular seal lip 15c-2 is provided at a radially outer edge of a side face 15c-1 of the vertical wall 15c so as to project in a direction of the axis X of the grommet 10. [0016] The tip end 15d of the side wall of the latch recess 15 at the reduced diameter side is partially varied in its outer diameter. Specifically, the tip ends 15d-1 of the side wall which correspond to 45 degree at both right and left sides from the bent side of the tip end 15d of the side wall have a diameter of 76.0mm (hl=38.Omm) on the axis X, and the tip ends 15d-3 of the remaining side wall, via the tip ends 15d-2 corresponding to 10 degree from both ends of the tip ends 15d-1 of the side wall, have a diameter of 75.0mm (h2=37.5mm) on the axis X. In short, the outer diameter of the tip end 15d-1 of the side wall is 5 made about 1.3% larger than the outer diameter of the tip end 15d-2 of the side wall. Moreover, a diameter of the bottom face 15b is made constant in the entire circumference, and the outer diameter of the tip end 15d-1 of the side wall at the bent side is made larger than the outer diameter of the tip end 15d-3 of the side wall at the other side opposite to the bent side, and hence, a height of the side wall at the bent side is made larger than a height of the side wall at the opposite side. Further, the tip end 15d-2 of the side wall interposed between the tip end 15d-1 and the tip end 15d-3 of the side wall is formed in an arc shape connecting an edge of the tip end 15d-1 of the side wall and an edge of the tip end 15d-3 of the side wall so *as to correct a difference in diameter between the tip end 15d-1 and the tip end 15d-3 of the side wall. [0017] Now, a work for mounting the grommet 10 to a vehicle body panel P will be described. As a first step, a wire harness W/H is inserted into a hollow part of the small diameter tubular part 12 and the enlarged diameter tubular part 14 of the grommet 10, and fixed to the first small diameter tubular portion 12a with a tape T. Then, the grommet 10 is pushed in from the large diameter side of the grommet 10 into a through hole H while the grommet is crushed with hand in a direction of a blank arrow mark in Fig. 3 (A) , and temporarily moved to an inside (N) of the vehicle room. [0018] Then, the small diameter tubular part 12 of the grommet 10 is pulled back to an outside (M) of the vehicle room, as shown in Fig. 3(B). On this occasion, substantially no pulling force is required until a circumferential edge of the through hole H arrives at a position where it has the same outer diameter as an inner diameter of the through hole H in the vehicle body panel P. When the through hole H has come into contact with the enlarged diameter tubular part 14 as shown in Fig. 3(C), a worker will feel a touch of click. [0019] When the worker pulls the grommet 10 from this position feeling the touch of click diagonally, that is, to the bent side of the small diameter tubular part 12 as shown in Fig. 3(D), the circumferential edge of the through hole H will pass by the tip end 15d of the side wall while inwardly flexing the tip end 15d, and will be dropped into the annular recess 15 as shown in Fig. 3 (E) , engaged to be 6 C:\NR onbT\DCC\GAV\2719S42 IDOC.I 102/2010 -7 sandwiched between the side wall 15a at the reduced diameter side and the vertical wall 15c. On this occasion, an inner peripheral face of the vehicle body panel P will come into contact with the seal lip 15c-2 of the vertical 5 wall '15c and waterproof performance can be reliably attained. [0020] According to the above described structure, although the pulling force of the grommet 10 is not likely to be 10 transmitted to the tip end 15d-3 of the side wall at the side opposite to the bent side, the circumferential edge of the through hole H is likely to ride across the tip end 15d-3 of the side wall, because the outer diameter of the tip end 15d-3 is made smaller. Thus, the circumferential 15 edge of the through hole H can be dropped into the annular recess 15 with a small pulling force. Moreover, although the outer diameter of the tip end 15d-1 of the side wall is made larger than that of the tip end 15d-3 of the side wall, the large insertion force will not be required for 20 dropping the circumferential edge of the through hole H into the annular recess 15 at the bent side, because the pulling force of the grommet 10 is likely to be transmitted to the tip end 15d-1. As the results, the grommet 10 can be easily mounted to the through hole in the vehicle body 25 panel with the small insertion force. Further, even though a force in a direction opposite to the pulling direction has been exerted on the grommet 10, the circumferential edge of the through hole H will not be easily detached from the annular recess 15, because the 30 outer diameter of the tip end 15d-1 of the side wall at the bent side where the force is likely to be transmitted is made larger. [0021] As apparent from the foregoing description, in the 35 grommet in which the small diameter tubular part and the enlarged diameter tubular part are bent with respect to each other, the pulling force of the grommet is not likely to be transmitted to the annular recess at the side opposite to the bent side. However, since the outer 40 diameter of the tip end of the side wall at the reduced diameter side which is opposite to the bent side is made smaller, the circumferential edge of the through hole can easily ride across the tip end of the side wall. As a result, it is possible to drop the circumferential edge of 45 the through hole into the annular recess with a small insertion force. Moreover, although the outer diameter of the tip end of the side wall at the bent side is made larger than that of the tip end at the side opposite to the bent side, a large insertion force will not be required for dropping the circumferential edge of the through hole into the annular recess at the bent side, because the pulling force of the grommet is likely to be transmitted to the tip end at the bent side. As the results, the grommet can be easily mounted to the through hole in the vehicle body panel with a small insertion force. Further, even though a force in a direction opposite to the pulling direction has been exerted on the grommet, the circumferential edge of the through hole will not be easily detached from the annular recess, because the outer diameter of the tip end of the side wall at the bent side where the force is likely to be transmitted is made larger. [Brief Description of the Drawings] [Fig. 1] Fig. 1 is a back view of a grommet in an embodiment according to the invention. [Fig. 21 Fig. 2 is a sectional view of the grommet taken along a line I-I. [Fig. 3] Figs. 3 (A) to (E) are views showing steps of mounting the grommet to a vehicle body panel. [Fig. 4] Fig. 4 is a view showing a conventional example. [Description of the Reference Numerals and Signs] 10 grommet 12 small diameter tubular part 14 enlarged diameter tubular part 15 annular recess 15a side wall at a reduced diameter side 15b bottom face 15c vertical wall 15d tip end of side wall P vehicle body panel H through hole W/H wire harness 8 C:\NRPonb\DCCGAV\2719842 1.DOC-I 102/2010 -9 Fig. 3(A) (PUSH IN) Fig. 3 (B) 5 (PULL) Fig. 3 (D) (PULL) 10 [0022] 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 15 group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. [0023] Many modifications will be apparent to those skilled in the art without departing from the scope of the present invention.