Duct connection structure

Abstract

In a duct connection structure, movement of the duct relative to the equipment is suppressed. [Solution] A duct connection structure 100 includes a sheet metal member 10 having a through hole 14 and a duct 20 inserted into the through hole 14, wherein the duct 20 comprises an insertion portion 22 inserted into the through hole 14 and a sealing rubber 30 having an annular lip 32 that contacts the inner surface 14A of the through hole 14, and the sealing rubber 30 has a plurality of strip-shaped base portions 35, 36 extending in the insertion direction so as to fill the gaps 31A between the annular lips 32, and the outer diameter of each base portion 35, 36 increases towards the tip in the insertion direction.

Description

Technical Field

[0006] , , , ,

[0001] This disclosure relates to the structure of the connection portion between a device and a duct.

Background Art

[0002] Patent Document 1 discloses a seal structure for a fender panel penetration portion of a duct. This seal structure includes an inlet duct, an air cleaner, and an annular seal member. The inlet duct has a cylindrical main body portion and a flange having a facing surface facing the fender panel. The seal member is attached to the facing surface, with its outer peripheral portion sandwiched between the fender panel and the flange portion, and its inner peripheral portion sandwiched between the air cleaner and the flange portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A seal rubber is used for the fitting portion between the duct and the device. However, the seal rubber has a low restraining force on the duct, and the duct may move relative to the device due to vibration. There have been cases where the two interfere with each other.

[0005] Therefore, an object of this disclosure is to suppress the movement of the duct relative to the device in a duct connection structure.

Means for Solving the Problems

[0006] The duct connection structure of the present disclosure is a duct connection structure including a device having a through hole and a duct that is inserted into the through hole and connected to the device, wherein the duct comprises an insertion portion that is inserted into the through hole and an annular sealing rubber attached to the outer circumferential surface of the insertion portion, the sealing rubber having a plurality of annular lips that contact the inner surface of the through hole and are arranged in the insertion direction, the sealing rubber having a plurality of strip-shaped base portions that extend in the insertion direction so as to fill the gaps between the plurality of annular lips, and the outer diameter of each base portion increases towards the tip in the insertion direction.

[0007] The base portion has high compressive strength, which increases the restraining force on the duct and suppresses its movement relative to the equipment. In addition, the multiple base portions provided in the circumferential direction contact the inner surface of the through hole, allowing for centering of the through hole and the duct. Furthermore, since the outer diameter of the base portion increases towards the tip in the insertion direction, it is possible to suppress the duct from moving in the opposite direction of insertion or in the direction of withdrawal. This suppresses the generation of abnormal noise caused by the duct interfering with the equipment due to vibration.

[0008] In the duct connection structure of this disclosure, the outer diameter of the base portion may be larger than the inner diameter of the through hole at the insertion direction end, and smaller than the inner diameter of the through hole and smaller than the outer diameter of the annular lip at the opposite end from the insertion direction end.

[0009] As a result, at the insertion end, the base portion contacts the inner surface of the through hole, compressing and generating a large restraining force, while at the opposite insertion end, the outer edge of the annular lip protruding from the outer surface of the base portion contacts the inner surface of the through hole, ensuring a seal. This allows the duct to be fixed with a large restraining force while ensuring a seal between the duct and the through hole.

[0010] In the duct connection structure of this disclosure, the duct includes an outer flange connected to the insertion portion on the side opposite to the insertion direction and positioned outside the equipment, the insertion portion includes a plurality of engagement claws in the circumferential direction that protrude from the outer peripheral surface at the tip in the insertion direction and face the inner surface of the equipment, and the base portion may be positioned between the plurality of engagement claws and the outer flange.

[0011] In this way, since the base portion is positioned between the engaging claw and the outer flange, the position of the sealing rubber in the insertion direction relative to the duct is fixed, and movement of the duct in the insertion direction can be suppressed.

[0012] In the duct connection structure of this disclosure, the insertion portion has a plurality of wedge portions in the circumferential direction at the tip portion in the insertion direction, which protrude from the outer peripheral surface and whose protrusion height decreases as it approaches the tip, and the base portion may be arranged between the plurality of wedge portions and the outer flange.

[0013] In this way, since the base is positioned between the wedge and the outer flange, the position of the sealing rubber in the insertion direction relative to the duct is fixed, and movement of the duct in the insertion direction can be suppressed.

[0014] In the duct connection structure of the present disclosure, the sealing rubber includes an annular flange portion provided at the end of the sealing rubber opposite to the insertion direction and positioned outside the equipment, wherein the flange portion is positioned between the outer flange and the outer surface of the equipment, and when the insertion portion is inserted into the through hole and fitted into the through hole, the outer flange may be pressed against the outer surface of the equipment via the flange portion.

[0015] The outer diameter of the base increases towards the end in the insertion direction. In other words, the outer diameter of the base is larger at the end in the insertion direction and smaller at the end opposite the insertion direction. Therefore, when the insertion part is inserted into the through hole, the insertion part is pulled towards the end in the insertion direction, and the outer flange is pressed against the outer surface of the equipment via the flange. This defines the position of the duct in the insertion direction, thus suppressing the movement of the duct relative to the equipment. This suppresses the generation of abnormal noise caused by the duct interfering with the equipment due to vibration. [Effects of the Invention]

[0016] This disclosure provides a duct connection structure that can suppress the movement of the duct relative to the equipment. [Brief explanation of the drawing]

[0017] [Figure 1] This is a perspective view showing the duct connection structure of the embodiment. [Figure 2] This is an exploded cross-sectional view of the general section. [Figure 3] This is a cross-sectional view of the general section, showing the duct connection structure viewed from the lower left towards the upper left, along AA as shown in Figure 1. [Figure 4] This is an exploded cross-sectional view of the portion including the engaging claws. [Figure 5] This is a cross-sectional view of the portion including the wedge. [Figure 6] This is a cross-sectional view of the portion including the engaging claw, showing the duct connection structure viewed from below along BB as shown in Figure 1. [Figure 7] This is a cross-sectional view of the portion including the wedge, showing the duct connection structure viewed from the left side along CC as shown in Figure 1. [Modes for carrying out the invention]

[0018] Hereinafter, the duct connection structure 100 of the embodiment will be described with reference to the drawings. As shown in FIG. 1, the duct connection structure 100 includes a sheet metal member 10 and a duct 20. Incidentally, FR, UP, and RH shown in the figure indicate the insertion direction when the duct 20 is inserted into the sheet metal member 10, the upward direction, and the right direction of the sheet metal member 10 and the duct 20, respectively. Also, the opposite directions of FR, UP, and RH indicate the reverse insertion direction, the downward direction, and the left direction of the sheet metal member 10 and the duct 20. <00000�1> The sheet metal member 10 is part of a device to which the duct 20 is connected. The sheet metal member 10 may be, for example, a member that constitutes an apron of a vehicle body. Also, the duct 20 may be an air duct that is connected to a hole provided in the apron and sends air from inside the fender to the inside of the front compartment at the front of the vehicle.

[0020] As shown in FIGS. 1 and 2, the sheet metal member 10 includes a flat plate portion 11 and a press-molded cylindrical portion 12. The cylindrical portion 12 defines a through hole 14 that penetrates the sheet metal member 10 in the plate thickness direction, and the inner peripheral surface 12A of the cylindrical portion 12 constitutes the inner surface 14A of the through hole 14. The side in the insertion direction of the flat plate portion is the inside 15 of the sheet metal member 10, and the side in the reverse insertion direction of the flat plate portion is the outside 16 of the sheet metal member 10. Also, the surface on the reverse insertion direction side of the flat plate portion 11 becomes the outer surface 11A of the sheet metal member 10.

[0021] The duct 20 includes a pipe 21, an insertion portion 22, and an outer flange 23. The pipe 21 is a cylindrical member. The insertion portion 22 is the tip portion on the insertion direction side of the pipe 21 and is the portion that is inserted into the through hole 14 of the sheet metal member 10 or into the cylindrical portion 12. The outer flange 23 is a plate-shaped annular member provided on the reverse insertion direction side of the insertion portion 22. The outer diameter of the outer flange 23 is larger than the inner diameter of the through hole 14 of the sheet metal member 10. As shown in FIG. 1, the outer flange 23 is located outside the sheet metal member 10 when the duct 20 is connected to the sheet metal member 10. <OO00099><00001OO> Next, the general part of the duct connection structure 100 will be described with reference to Figures 2 and 3. The general part is the portion of the duct 20 that does not have the engaging claws 25 and wedge portion 26, and the sealing rubber 30 that does not have the base portions 35 and 36. Here, Figure 1 shows a cross-section of the duct connection structure 100 viewed from the lower left in an upward direction along line AA.

[0023] As shown in Figure 2, the sealing rubber 30 is an annular member including a base 31, an annular lip 32, and a flange portion 33. The base 31 is a cylindrical portion. The annular lip 32 is an annular portion that rises radially outward from the outer surface of the base 31. As shown in Figure 2, the annular lip 32 has a roughly triangular cross-section that becomes thinner towards the radially outward side. Multiple annular lips 32 are arranged in a row in the insertion direction. There is a valley 31A between each annular lip 32. The flange portion 33 is an annular portion provided at the end opposite to the insertion direction. The outer diameter of the flange portion 33 is larger than the inner diameter of the through hole 14.

[0024] As shown by the white arrow in Figure 2, the sealing rubber 30 is attached to the outer circumferential surface 24 of the insertion portion 22. The dashed line in Figure 3 shows the state in which the sealing rubber 30 is attached to the duct 20. As shown in Figure 3, the sealing rubber 30 is attached to the outer circumferential surface 24 such that the flange portion 33 is in contact with the surface of the outer flange 23 of the duct 20 on the insertion side. As shown by the solid line in Figure 3, when the insertion portion 22 with the sealing rubber 30 attached is inserted into the through hole 14, a gap is created between the outer surface of the base 31 and the inner surface 14A of the through hole 14, and the outer circumferential end of the annular lip 32 rises toward the inner surface 14A of the through hole 14, contacting the inner surface 14A and sealing the space between the sheet metal member 10 and the duct 20.

[0025] Next, the structure of the portion of the duct connection structure 100 equipped with the engaging claw 25 and the portion equipped with the wedge 26 will be described with reference to Figures 1, 4 through 7. Here, Figure 6 is a cross-sectional view of the duct connection structure 100 viewed from below along BB shown in Figure 1, and Figure 7 is a cross-sectional view of the duct connection structure 100 viewed from the left side along CC shown in Figure 1. The same reference numerals are used for the same parts as those described earlier with reference to Figures 2 and 3, and their explanations will be omitted.

[0026] As shown in Figure 1, there are two engaging claws 25, one on each side of the tip of the pipe 21 in the insertion direction. The circumferential width of the engaging claws 25 is W1. Similarly, there are two wedge portions 26, one above and one below the tip of the pipe 21 in the insertion direction. The circumferential width of the wedge portion 26 is W2. Note that in Figure 1, only the left engaging claw 25 and the upper wedge portion 26 are shown, while the right engaging claw 25 and the lower wedge portion 26 are omitted from the illustration.

[0027] Furthermore, as shown in Figure 1, a base portion 35 is provided in the part of the seal rubber 30 corresponding to the engaging claw 25. Also, a base portion 36 is provided in the part of the seal rubber 30 corresponding to the wedge portion 26.

[0028] First, the engaging claw 25 and the wedge portion 26 will be described. As shown in Figure 4, the engaging claw 25 has an engaging surface 25A that protrudes radially outward from the outer peripheral surface 24 of the insertion portion 22 and faces the end face on the inner 15 side of the cylindrical portion 12, and a tip-inclined surface 25B on the tip side in the insertion direction. The outer diameter of the engaging claw 25 is larger than the inner diameter of the cylindrical portion 12. The end face on the inner 15 side of the cylindrical portion 12 is part of the inner surface of the sheet metal member 10. The engaging surface 25A also forms a recess between it and the outer flange 23 into which the sealing rubber 30 fits.

[0029] Furthermore, as shown in Figure 5, the wedge portion 26 has a vertical surface 26A that protrudes radially outward from the outer peripheral surface 24 of the insertion portion 22 and forms a recess into which the sealing rubber 30 fits between it and the outer flange 23, and a tip-inclined surface 26B on the tip side in the insertion direction. The outer diameter of the wedge portion 26 is smaller than the inner diameter of the cylindrical portion 12.

[0030] Next, the base portion 35 will be described. As shown in Figure 4, the base portion 35 is a strip-shaped portion that extends in the insertion direction to fill the gap 31A between the annular lips 32. The base portion 35 is molded integrally with the annular lips 32 when the seal rubber 30 is molded. The circumferential width of the base portion 35 is the same as the width of the engaging claw 25, W1, or slightly narrower than W1. The base portion 35 has higher radial compressive strength than the annular lips 32. The base portion 35 includes a front wall portion 35C, a first inclined portion 35A, and a second inclined portion 35B.

[0031] The front wall portion 35C is the portion of the general seal rubber 30 that rises from the base 31 at the insertion point, as shown in Figure 2. The outer diameter of the front wall portion 35C is larger than the outer diameter of the outer circumference of the annular lip 32. Also, the outer diameter of the front wall portion 35C is larger than the inner diameter of the through hole 14.

[0032] The first inclined portion 35A is the part on the insertion side towards the tip, whose outer diameter is larger than the inner diameter of the through hole 14. The first inclined portion 35A extends in the reverse insertion direction so as to fill the valley 31A between the front wall portion 35C and the annular lip 32. The outer diameter of the first inclined portion 35A decreases as it moves in the reverse insertion direction. The height of the first inclined portion 35A decreases as it moves in the reverse insertion direction, and the outer surface of the first inclined portion 35A is a first inclined surface 35D that becomes lower as it moves in the reverse insertion direction. Conversely, the outer diameter of the first inclined portion 35A increases as it moves towards the tip in the insertion direction, and the height of the first inclined portion 35A increases as it moves towards the tip in the insertion direction. Also, at the tip in the insertion direction, the outer diameter of the first inclined portion 35A is approximately the same as, or slightly larger than, the outer diameter of the outer circumference of the annular lip 32. For this reason, the annular lip 32 at the tip in the insertion direction is embedded in the first inclined surface 35D of the first inclined portion 35A.

[0033] The second inclined portion 35B is the portion connected to the side of the first inclined portion 35A that is not in the insertion direction, and whose outer diameter is smaller than the inner diameter of the through hole 14. Similar to the first inclined portion 35A, the outer diameter of the second inclined portion 35B decreases as it is moved away from the insertion direction. Also, the height of the second inclined portion 35B decreases as it is moved away from the insertion direction, and the outer surface of the second inclined portion 35B is a second inclined surface 35E that becomes lower as it is moved away from the insertion direction. Conversely, the outer diameter of the second inclined portion 35B increases as it is moved towards the tip in the insertion direction, and the height of the second inclined portion 35B increases as it is moved towards the tip in the insertion direction. Also, the outer diameter of the second inclined portion 35B is smaller than the outer diameter of the outer circumference of the annular lip 32. For this reason, in the second inclined portion 35B, the outer circumference of the annular lip 32 protrudes from the second inclined surface 35E of the second inclined portion 35B. Furthermore, since the outer diameter of the second inclined portion 35B decreases as it moves away from the insertion direction, the protruding length of the second inclined portion 35B of the annular lip 32 from the second inclined surface 35E increases as it moves away from the insertion direction.

[0034] Next, the base portion 36 will be described. As shown in Figure 5, the base portion 36, like the base portion 35, is a strip-shaped portion that extends in the insertion direction to fill the gap 31A between the annular lips 32. Like the base portion 35, the base portion 36 is molded integrally with the annular lips 32 when the seal rubber 30 is molded. The circumferential width of the base portion 36 is W2, or slightly narrower than W2, similar to the width of the wedge portion 26. Like the base portion 35, the base portion 36 includes a front wall portion 36C, a first inclined portion 36A, and a second inclined portion 36B.

[0035] The front wall portion 36C has the same shape as the front wall portion 35C except that its tip in the insertion direction is inclined toward the upper end of the vertical surface 26A of the wedge portion 26 and that it is different in width, so its description is omitted. Also, the first inclined portion 36A and the second inclined portion 36B have the same shape as the first inclined portion 35A and the second inclined portion 35B except that they are different in width, and are equipped with the first inclined surface 36D and the second inclined surface 36E, so their description is omitted.

[0036] As shown by the white arrows in Figures 4 and 5, the sealing rubber 30 is attached to the outer circumferential surface 24 of the insertion portion 22. When attaching the sealing rubber 30 to the insertion portion 22, the sealing rubber 30 is stretched and attached to the outer circumferential surface 24 through the engaging claws 25 and wedge portion 26. The dashed lines in Figures 6 and 7 show the state in which the sealing rubber 30 is attached to the duct 20. The sealing rubber 30 is fitted into the recess between the outer flange 23 and the engaging claws 25, and into the recess between the outer flange 23 and the wedge portion 26. When the sealing rubber 30 is attached to the outer circumferential surface 24, the flange portion 33 contacts the insertion-direction side surface of the outer flange 23 of the duct 20, the front wall portion 35C contacts the engaging surface 25A of the engaging claws 25, and the front wall portion 36C contacts the vertical surface 26A of the wedge portion 26. As a result, the sealing rubber 30 is fixed to the pipe 21 or the insertion portion 22 in the insertion direction.

[0037] When inserting the insertion portion 22 of the duct 20, to which the sealing rubber 30 is attached, into the through hole 14 of the sheet metal member 10, the insertion portion 22 is inserted at an angle to the through hole 14, the engaging surface 25A of one engaging claw 25 is hooked onto the end face on the inner 15 side of the cylindrical portion 12, the inclined tip surface 25B of the other engaging claw 25 and the inclined tip surface 26B of the wedge portion 26 are brought into contact with the funnel-shaped portion on the outer side of the cylindrical portion 12, and the duct 20 is pushed in while raising it upright so that the insertion portion 22 is coaxial with the through hole 14.

[0038] The solid line in Figure 6 shows the state in which the insertion portion 22, including the engaging claw 25, is inserted into the through hole 14. When the insertion portion 22 is inserted into the through hole 14, the engaging claw 25 is inserted into the interior 15 of the sheet metal member 10 and faces the end face on the interior 15 side of the cylindrical portion 12 via the sealing rubber 30.

[0039] Furthermore, since the outer diameter of the first inclined portion 35A of the base portion 35 is larger than the inner diameter of the through hole 14, when the insertion portion 22 is inserted into the through hole 14, the first inclined surface 35D of the first inclined portion 35A is compressed by the inner surface 14A of the through hole 14, and the reaction force causes it to fit into the inner surface 14A of the through hole 14. Since the base portions 35 and 36 have high compressive strength in the radial direction, the first inclined portion 35A fits into the inner surface 14A of the through hole 14 with a large reaction force.

[0040] Similarly, since the outer diameter of the first inclined portion 36A of the base portion 36 is larger than the inner diameter of the through hole 14, as shown by the solid line in Figure 7, when the insertion portion 22 is inserted into the through hole 14, the first inclined surface 36D of the first inclined portion 36A is compressed by the inner surface 14A of the through hole 14, and fits into the inner surface 14A of the through hole 14 with a large reaction force.

[0041] Since the first inclined portions 35A and 36A of the four base portions 35 and 36 are positioned above, below, and to the left and right of the duct 20, when the first inclined portions 35A and 36A are fitted into the inner surface 14A of the through hole 14, the insertion portion 22 can be held coaxially with respect to the through hole 14.

[0042] On the other hand, since the outer diameters of the second inclined portions 35B and 36B are smaller than the inner diameter of the through hole 14, when the first inclined portions 35A and 36A, which have high compressive strength, are fitted onto the inner surface 14A of the through hole 14, a gap is created between the second inclined surfaces 35E and 36E of the second inclined portions 35B and 36B and the inner surface 14A of the through hole 14. Also, in the general portion, a gap is created between the outer surface of the base 31 and the inner surface 14A of the through hole 14. For this reason, the annular lip 32 of the general portion and the annular lip 32 of the second inclined portions 35B and 36B are not crushed by the inner surface 14A of the through hole 14, and their outer peripheral ends rise towards the inner surface 14A of the through hole 14, contacting the inner surface 14A and sealing the space between the sheet metal member 10 and the duct 20.

[0043] Furthermore, the outer diameters of the first inclined sections 35A, 36A and the second inclined sections 35B, 36B decrease as they move away from the insertion direction, and the first inclined surfaces 35D, 36D and the second inclined surfaces 35E, 36E of the first inclined sections 35A, 36A and the second inclined sections 35B, 36B become lower in the direction away from the insertion direction. As a result, as shown in Figures 6 and 7, the radial load F of the duct 20 applied from the inner surface 14A of the through hole 14 to the first inclined surfaces 35D, 36D and the second inclined surfaces 35E, 36E is decomposed into a vertical load F1 perpendicular to the first inclined surfaces 35D, 36D and the second inclined surfaces 35E, 36E, and a lateral force F2 parallel to the first inclined surfaces 35D, 36D and the second inclined surfaces 35E, 36E and toward the tip in the insertion direction. Therefore, when the insertion portion 22 is inserted into the through hole 14, the insertion portion 22 is pulled towards the tip in the insertion direction by the lateral force F2. This lateral force F2 then presses the outer flange 23 of the duct 20 against the outer surface 11A of the flat plate portion 11 via the flange portion 33 of the sealing rubber 30. This defines the position of the duct 20 in the insertion direction, thereby suppressing movement of the duct 20 relative to the sheet metal member 10 in the insertion direction. Furthermore, this suppresses the generation of abnormal noise due to the duct 20 interfering with the sheet metal member 10 due to vibration.

[0044] As explained above, the duct connection structure 100 has high compressive strength in the base portions 35 and 36, which allows for a greater restraining force on the duct 20 and suppresses movement of the duct 20 to the sheet metal member 10. This suppresses the generation of abnormal noise caused by vibrations interfering with the sheet metal member 10 due to the duct 20. In addition, the four circumferentially arranged base portions 35 and 36 contact the inner surface 14A of the through hole 14, thereby enabling centering of the through hole 14 and the duct 20.

[0045] Furthermore, the outer diameters of the base portions 35 and 36 are larger than the inner diameter of the through hole 14 at the insertion end, and smaller than the inner diameter of the through hole 14 and smaller than the outer diameter of the annular lip 32 at the opposite end of the insertion direction. As a result, at the insertion end, the first inclined surfaces 35D and 36D contact the inner surface 14A of the through hole 14, compressing it and creating a large restraining force, while at the opposite end of the insertion direction, the outer peripheral end of the annular lip 32 protruding from the second inclined surfaces 35E and 36E contacts the inner surface 14A of the through hole 14, ensuring a seal. Thus, the duct connection structure 100 can fix the duct 20 with a large restraining force and ensure a seal between the duct 20 and the through hole 14.

[0046] In the duct connection structure 100, the base portions 35 and 36 are positioned between the engaging claws 25 and the outer flange 23, or between the wedge portion 26 and the outer flange 23, so that the position of the sealing rubber 30 in the insertion direction relative to the duct 20 is fixed, and movement of the duct 20 in the insertion direction can be suppressed.

[0047] Furthermore, the duct connection structure 100 has base portions 35 and 36 with outer diameters that are larger at the insertion end and smaller at the opposite end. As a result, when the insertion portion 22 is inserted into the through hole 14, the insertion portion 22 is pulled towards the insertion end, and the outer flange 23 is pressed against the outer surface 11A of the sheet metal member 10 via the flange portion 33. This defines the position of the duct 20 in the insertion direction, thereby suppressing movement of the duct 20 relative to the sheet metal member 10. In addition, this suppresses the generation of abnormal noise due to the duct 20 interfering with the sheet metal member 10 due to vibration.

[0048] In the above description, the duct 20 is described as having two engaging claws 25 and two wedge portions 26, with base portions 35 and 36 provided at positions corresponding to the engaging claws 25 and wedge portions 26, but it is not limited to this. There only need to be three or more base portions 35 and 36 arranged in the circumferential direction so that the through hole 14 and the duct 20 can be centered. For example, three engaging claws 25 and base portions 35 may be provided in the circumferential direction, and no wedge portions 26 may be provided. Alternatively, two engaging claws 25 and base portions 35, and two or more wedge portions 26 and base portions 36 may be provided in the circumferential direction.

[0049] Furthermore, in the case of a duct 20 that does not have engaging claws 25 and wedge portions 26, three or more base portions 35 and 36 may be arranged in the circumferential direction.

[0050] Furthermore, although the sheet metal member 10 was described as an example of equipment, the equipment does not have to be made of sheet metal. For example, the equipment may be a thick casting with a through hole 14. In this case, it does not have to have a cylindrical portion 12.

[0051] Furthermore, although the above description assumes that the base portions 35 and 36 are molded integrally with the annular lip 32 during the molding of the sealing rubber 30, the explanation is not limited to this. For example, the annular lip 32 may be a separate rectangular parallelepiped rubber part having multiple protrusions on its lower surface that fill the gaps 31A between the multiple annular lips 32. In this case, the base portions 35 and 36 may be fitted from above between the annular lips 32 and fixed in place by adhesive. [Explanation of Symbols]

[0052] 10 Sheet metal member, 11 Flat plate section, 11A Outer surface, 12 Cylindrical section, 12A Inner circumferential surface, 14 Through hole, 14A Inner surface, 15 Interior, 16 Exterior, 20 Duct, 21 Pipe, 22 Insertion section, 23 Outer flange, 24 Outer circumferential surface, 25 Engaging claw, 25A Engaging surface, 25B, 26B Inclined tip surface, 26 Wedge section, 26A Vertical surface, 30 Seal rubber, 31 Base, 31A Groove, 32 Annular lip, 33 Flange section, 35, 36 Base section, 35A, 36A First inclined section, 35B, 36B Second inclined section, 35C, 36C End wall section, 35D, 36D First inclined surface, 35E, 36E Second inclined surface, 100 Duct connection structure.

Claims

1. Equipment with through holes, A duct connection structure comprising a duct inserted into the through hole and connected to the equipment, The aforementioned duct is, The insertion part is inserted into the aforementioned through hole, The seal rubber is attached to the outer circumferential surface of the insertion portion, and comprises a plurality of annular lips that contact the inner surface of the through hole and are arranged in the insertion direction, The sealing rubber comprises a plurality of strip-shaped base portions extending in the insertion direction in the circumferential direction so as to fill the gaps between the plurality of annular lips, The outer diameter of each base portion increases towards the tip in the insertion direction. A duct connection structure characterized by the following.

2. A duct connection structure according to claim 1, The outer diameter of the base portion is larger than the inner diameter of the through hole at the insertion end, and smaller than the inner diameter of the through hole and smaller than the outer diameter of the annular lip at the opposite end from the insertion end. A duct connection structure characterized by the following.

3. The duct connection structure according to claim 2, The duct is equipped with an outer flange that is connected to the side of the insertion portion opposite to the insertion direction and positioned outside the equipment, The insertion portion is provided with a plurality of engagement claws in the circumferential direction that protrude from the outer surface at the tip in the insertion direction and face the inner surface of the device. The base portion is positioned between the plurality of engagement claws and the outer flange. A duct connection structure characterized by the following.

4. The duct connection structure according to claim 3, The insertion portion has a plurality of wedge-shaped portions in the circumferential direction at the tip in the insertion direction, which protrude from the outer circumferential surface and whose protrusion height decreases as they approach the tip. The base portion is positioned between the plurality of wedge portions and the outer flange. A duct connection structure characterized by the following.

5. A duct connection structure according to claim 3 or 4, The sealing rubber includes an annular flange portion provided at the end of the sealing rubber opposite to the insertion direction and positioned outside the device, The flange portion is positioned between the outer flange and the outer surface of the equipment. When the insertion portion is inserted into the through hole and fitted into the through hole, the outer flange is pressed against the outer surface of the device via the flange portion. A duct connection structure characterized by the following.

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