Grommet

Abstract

A grommet is provided, which can prevent the sealing portion from rolling up even if a pushing force is applied from an oblique direction so that the sealing portion abuts against the instrument panel. The grommet (G) involved in the present invention is provided with a thick wall portion (4) on the outer side of the second flexible portion (22). As a result, in the pushing force (F) applied from the cylindrical base (1) side toward the sealing portion (3) side, the panel parallel component (F1) parallel to the instrument panel (DP) is difficult to transmit, while the panel vertical component (F2) perpendicular to the instrument panel (DP) is easy to transmit. As a result, the panel vertical component (F2) becomes relatively large, and even if a pushing force (F) is applied from an oblique direction so that the sealing portion (3) abuts against the instrument panel (DP), the rolling up of the sealing portion (3) due to overturning can be prevented.

Description

[0001] Technical Area

[0002] The present invention relates to a grommet for covering the periphery of a steering shaft used in, for example, an automobile. The steering shaft is inserted through a vehicle body panel (so-called instrument panel) that separates a vehicle cabin from an engine compartment. Background Art

[0003] Figure 6 The conventional grommet Gx shown in the figure has a cylindrical shape formed of a predetermined rubber material, and is sandwiched between a steering shaft SH constituting a steering shaft of a steering device mounted on a vehicle and a shaft through hole DP1 of an instrument panel DP of a vehicle body through which the steering shaft SH penetrates. That is, the grommet Gx suppresses the intrusion of rainwater, dust, etc. through the shaft through hole DP1 by mounting one end side on the upper part of the steering gear box GB and elastically contacting the other end side with the vehicle outer side hole edge DP2 of the shaft through hole DP1.

[0004] More specifically, the grommet Gx is installed in such a manner that the first sealing portion 101 formed in an expanded diameter shape on one end side of the cylindrical base 100 surrounding the steering shaft SH is closely attached to the outer side of the gear box cylindrical portion GB1 provided at the upper end of the steering gear box GB. On the other hand, for the grommet Gx, the second sealing portion 102 extending from the other end side of the cylindrical base 100 via the flexible portion 103 bent (bent) outwardly in a folded shape elastically abuts against the vehicle outer side hole edge DP2 of the shaft through hole DP1 by utilizing the elastic force generated by the bending of the flexible portion 103.

[0005] In addition, as a technology describing a grommet having a configuration similar to the above-described configuration, for example, the technology described in the following patent documents is known.

[0006] Prior Art Literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2011-79473 Summary of the invention

[0009] Problems to be solved by the invention

[0010] The assembly of the above-mentioned conventional eyelet Gx is carried out in the following manner: with the above-mentioned first sealing portion 101 pre-embedded in the gear box cylindrical portion GB1 of the steering gear box GB, the steering shaft SH is passed through the shaft through hole DP1 of the instrument panel DP, and then the above-mentioned second sealing portion 102 is brought into contact with the vehicle outer side hole edge DP2 of the shaft through hole DP1.

[0011] However, in order to avoid interference with other components installed in the engine compartment of the vehicle during assembly, the assembly direction of the grommet Gx is sometimes limited. In particular, it is not possible to assemble the second sealing portion 102 so that it abuts perpendicularly to the hole edge DP2 on the vehicle outer side of the shaft through hole DP1, and sometimes it is necessary to assemble the second sealing portion 102 so that it abuts obliquely to the hole edge DP2 on the vehicle outer side of the shaft through hole DP1. In this case, the pressing force F acting on the flexible portion 103 acts obliquely to the hole edge DP2 on the vehicle outer side of the shaft through hole DP1.

[0012] Therefore, according to the structure of the conventional grommet Gx, since the wall thickness of the flexible portion 103 is relatively smaller than that of the cylindrical base 100, the rigidity of the flexible portion 103 relative to the cylindrical base 100 becomes relatively low, and therefore, most of the above-mentioned pushing force F will escape toward the outside extending from the flexible portion 103, that is, in the horizontal direction, and as a result, the panel parallel component F1 becomes relatively larger than the panel vertical component F2. Therefore, it is not possible to obtain a sufficient pushing force (panel vertical component F2) against the vehicle outer side hole edge DP2 of the shaft through hole DP1, such as Figure 7 As shown, depending on the assembling form from the above-mentioned oblique direction, the second sealing portion 102 may fall over, and there is a possibility that the second sealing portion 102 may be rolled up. Summary of the invention

[0014] The present invention has been made in view of the above technical problems, and an object of the present invention is to provide a grommet which can suppress the seal portion from turning over even when a pressing force acts from an oblique direction and the seal portion contacts an instrument panel.

[0015] Solutions to Solve Problems

[0016] The present invention provides a grommet as one of its modes, characterized in that the grommet comprises: a cylindrical base portion, the cylindrical base portion is cylindrical and covers the outer peripheral side of a steering shaft, the steering shaft passes through a shaft through hole, and the shaft through hole is throughly provided in a dashboard of a vehicle body that separates a vehicle compartment from an engine compartment; and a sealing portion, the sealing portion is provided via a flexible portion, and abuts against a hole edge of the shaft through hole on the vehicle side when assembled to the vehicle body, the flexible portion being able to extend from an axial end portion of the cylindrical base portion. The flexible portion is axially deformed in a manner of bulging toward the radially outer side of the above-mentioned cylindrical base, and the above-mentioned flexible portion has a first flexible portion and a second flexible portion. The first flexible portion extends from the axial end of the above-mentioned cylindrical base toward the radially outer side of the above-mentioned cylindrical base, and the second flexible portion extends from the above-mentioned first flexible portion toward the above-mentioned sealing portion in a curved manner and has a bending portion that can be bent in the axial direction. On the outer side of the above-mentioned second flexible portion, a thick-walled portion is provided to form the above-mentioned second flexible portion to be thicker than the above-mentioned first flexible portion.

[0017] According to this configuration, the thick-walled portion provided on the outside of the second flexible portion increases the rigidity of the second flexible portion including the bending portion as the flexible portion on the sealing portion side, and as a result, the rigidity of the first flexible portion as the flexible portion on the tubular base side is relatively reduced. Thus, among the pushing force acting from the tubular base side to the sealing portion side, the panel parallel component parallel to the instrument panel is difficult to be transmitted to the sealing portion side as the rigidity of the second flexible portion caused by the thick-walled portion is increased. On the other hand, the panel vertical component perpendicular to the instrument panel is easily transmitted to the sealing portion side as the rigidity of the first flexible portion is relatively reduced. As a result, the panel vertical component of the pushing force acting from the tubular base side to the sealing portion side can be fully ensured.

[0018] Here, as a preferred first mode of the present invention, it is preferred that the above-mentioned grommet is assembled in a manner that the above-mentioned sealing portion abuts against the above-mentioned instrument panel at an angle, and the above-mentioned thick-walled portion is only arranged in the following area within the circumferential area of ​​the above-mentioned second flexible portion: on the assembly direction side of the above-mentioned grommet than an assembly direction orthogonal line passing through the center of the above-mentioned sealing portion and orthogonal to the assembly direction of the above-mentioned grommet.

[0019] In this way, when the grommet is assembled from an inclined direction relative to the instrument panel, it is preferred that the thick-walled portion is only provided in an area within the circumferential area of ​​the second flexible portion that is located on the assembly direction side of the grommet relative to a line orthogonal to the grommet assembly direction, i.e., an area where the sealing portion is prone to overturning when the grommet is installed.

[0020] According to this configuration, the rigidity of the second flexible portion is increased only in the circumferential region of the second flexible portion where the seal portion is likely to fall down when the grommet is attached, thereby effectively preventing the seal portion in this region from falling down.

[0021] In other words, by not providing a thick-walled portion in the circumferential area of ​​the second flexible portion where the sealing portion is less likely to overturn when the eyelet is installed, it is possible to suppress unnecessary increase in the rigidity of the second flexible portion in this area and to suppress adverse conditions caused by the unnecessary increase in the rigidity of the second flexible portion.

[0022] In addition, as a preferred second embodiment of the present invention, it is preferred that the above-mentioned thick-walled portion is formed in the following manner: in the free state of the above-mentioned grommet, the axial end portion of the above-mentioned tubular base side of the above-mentioned thick-walled portion is the same height as the base side of the above-mentioned first flexible portion, or is lower than the base side of the above-mentioned first flexible portion.

[0023] In this way, by forming the end of the tubular base side of the thick-walled portion in the free state of the grommet to be the same as or lower than the base side of the first flexible portion, there is no possibility that the base side of the first flexible portion will become an undercut during the mold separation when molding the grommet, thereby improving the formability of the grommet.

[0024] Furthermore, as a preferred third mode of the present invention, it is preferred that the thick-walled portion is extended to the following position: even if the inner peripheral side of the sealing portion falls over and moves away from the instrument panel during assembly of the grommet, the axial end of the sealing portion side of the thick-walled portion does not abut against the instrument panel.

[0025] In this way, the thick-walled portion is constructed so that the axial end of the sealing portion side of the thick-walled portion does not abut the instrument panel even if the second flexible portion overturns in the axial direction such that the inner circumferential side of the sealing portion separates from the instrument panel during assembly of the grommet. When the grommet is assembled, the axial end of the sealing portion side of the thick-walled portion abuts against the instrument panel, thereby preventing the overturning of the sealing portion from being further promoted.

[0026] Effects of the Invention

[0027] According to the present invention, by providing a thick wall portion on the outer side of the second flexible portion, in the pushing force acting from the cylindrical base side toward the sealing portion side, the panel parallel component parallel to the instrument panel is difficult to transmit, while the panel vertical component perpendicular to the instrument panel is easy to transmit. As a result, the panel vertical component becomes relatively large, which can suppress the rolling up of the sealing portion due to overturning. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a cross-sectional view of the main parts showing a state where a steering device including a grommet according to the present invention is assembled to a vehicle body.

[0029] Figure 2 yes Figure 1 Bottom view of the grommet shown.

[0030] Figure 3 The free state of the grommet is shown Figure 2 An enlarged view of the main part of the AA line section.

[0031] Figure 4 The assembled state of the grommet is shown Figure 2 An enlarged view of the main part of the AA line section.

[0032] Figure 5 The seal part is shown in the state of being overturned during the assembly of the grommet. Figure 2 An enlarged view of the main part of the AA line section.

[0033] Figure 6 This is an enlarged cross-sectional view of a main part of a conventional grommet showing the free state of the grommet.

[0034] Figure 7 This is an enlarged cross-sectional view of a main part of the grommet showing a state in which the sealing portion is turned over during assembly of the conventional grommet. DETAILED DESCRIPTION

[0035] Hereinafter, embodiments of the grommet according to the present invention will be described in detail based on the drawings. In the following embodiments, a mode in which the grommet according to the present invention is applied to a steering device of an automobile as in the related art is shown.

[0036] (Constitution of Grommet)

[0037] Figure 1 1 is a cross-sectional view of the main parts showing the state in which the steering device including the grommet G is installed on the vehicle body, and is a schematic diagram showing the steering device with only the instrument panel DP shown in cross section. Figure 1 The upper side of the vertical direction is defined as "up", and the lower side corresponding to the vertical direction is defined as Figure 1 The lower side of is defined as “lower” and the description is given as such.

[0038] like Figure 1 As shown, the steering device has a steering shaft SH having 1st to 3rd steering shafts SH1 to SH3, and the 1st to 3rd steering shafts SH1 to SH3 are connected by 1st and 2nd universal joints J1 and J2 which are well-known universal joints. For the steering shaft SH, the 1st steering shaft SH1 arranged at one end side of the axial direction faces the inside of the vehicle and is connected to the steering wheel SW. In addition, for the steering shaft SH, the 3rd steering shaft SH3 arranged at the other end side of the axial direction passes through the instrument panel DP as the vehicle body panel and faces the inside of the engine compartment, and its terminal side is connected to the wheel not shown in the figure via a prescribed steering mechanism (such as a rack & pinion mechanism, etc.) housed inside the steering gear box GB.

[0039] Furthermore, a grommet G is interposed between the shaft through hole DP1 penetrating the instrument panel DP and the third steering shaft SH3 to keep the inside and outside of the vehicle compartment watertight. The grommet G is in a cylindrical shape formed of a predetermined rubber material, and has a cylindrical base 1 covering the outer periphery of the third steering shaft SH3 penetrating the instrument panel DP, a flexible portion 2 extending in a curved shape from one axial end (upper end) of the cylindrical base 1 toward the radial outer side and capable of axial bending and deformation of the third steering shaft SH3, and a sealing portion 3 provided at the terminal end (upper end) of the flexible portion 2 and capable of abutting against the vehicle outer side hole edge DP2 of the shaft through hole DP1 in a state assembled to the vehicle body (instrument panel DP), and these portions are integrally formed by mold molding.

[0040] The cylindrical base 1 includes: a general portion 11 covering the outer periphery of the third steering shaft SH3; an installation base 12 which is expanded in a step-like manner toward one axial end side (lower end side) of the general portion 11 and is installed on a substantially cylindrical gear box cylindrical portion GB1 provided at the upper end portion of the steering gear box GB; and a connecting base 13 which is formed in an expanded shape toward the other axial end side (upper end side) of the general portion 11 and connects the general portion 11 and the flexible portion 2.

[0041] The general portion 11 is formed in a substantially cylindrical shape and extends along the axial direction of the third steering shaft SH3 at an angle relative to the instrument panel DP. In other words, the cylindrical base 1 extends along the center axis CS of the third steering shaft SH3 intersecting the center axis CH of the shaft through hole DP1.

[0042] The mounting base 12 is set to be stepped with respect to the general part 11, and has a lip edge (not shown) on the inner circumference side so as to be closely attached to the outer circumference of the gear box cylindrical part GB1. That is, the mounting base 12 is set to be liquid-tight between the mounting base 12 and the gear box cylindrical part GB1 by making the above-mentioned lip edge (not shown) closely attached to the outer circumference of the gear box cylindrical part GB1.

[0043] The connection base 13 is bent relative to the general portion 11 and extends along the central axis CH of the axial through hole DP1. In addition, the connection base 13 is set in an expanded diameter shape relative to the general portion 11, and is set to be larger than the general portion 11 and smaller than the outer diameter of the flexible portion 2. Specifically, the connection base 13 has: a conical first connection base 131 extending obliquely radially outward from the other axial end (upper end) of the general portion 11; and a second connection base 132 extending from the upper end of the first connection base 131 along the approximate central axis CH. In addition, between the first connection base 131 and the second connection base 132, there is provided a bending portion 133 (see Figure 3 ).

[0044] The flexible portion 2 is continuously provided in an annular shape at the upper end of the second connection base 132 over the entire circumferential area of ​​the second connection base 132, and is formed to be able to bend and deform in the axial direction of the third steering shaft SH3. In addition, a sealing portion 3 is provided at the upper end of the flexible portion 2, which can elastically contact the vehicle outer side hole edge DP2 of the shaft through hole DP1 based on the elastic force generated by the bending deformation of the flexible portion 2.

[0045] According to the above-mentioned structure, the grommet G is arranged in a clamped state with the aid of the gear box cylinder GB1 of the steering gear box GB and the vehicle outer side hole edge DP2 of the shaft through hole DP1 of the instrument panel DP, and based on the elastic force of the flexible portion 2 that is flexurally deformed, the mounting base 12 of the tubular base 1 elastically abuts against the end face of the gear box cylinder GB1 of the steering gear box GB, and the sealing portion 3 elastically abuts against the vehicle outer side hole edge DP2 of the shaft through hole DP1 of the instrument panel DP, thereby, the grommet G is assembled and held on the vehicle body in a state in which the sealing function is exerted.

[0046] in addition, Figure 1 The arrow Z shown in FIG. 1 shows the assembly direction of the grommet G relative to the vehicle body (instrument panel DP). That is, the grommet G is not in the direction in which the seal portion 3 abuts perpendicularly to the instrument panel DP, but in the direction in which the seal portion 3 abuts perpendicularly to the instrument panel DP, in order to avoid interference with other components mounted in the engine compartment (not shown). Figure 1 The assembly is performed so that the seal portion 3 as indicated by the arrow Z is in contact with the instrument panel DP at an angle.

[0047] Figure 2 The diagram is shown as viewed from the sealing portion 3 side. Figure 1 Bottom view of grommet G of grommet G shown.

[0048] Grommet G Figure 2 As shown in the figure, in a plan view, the general portion 11 and the mounting base 12 of the cylindrical base 1 are formed into a substantially circular shape, and the connecting base 13, the flexible portion 2 and the sealing portion 3 are formed in a substantially circular shape. Figure 2 In addition, Figure 2 The arrow D shown in FIG. 1 shows the grommet G being moved toward the vehicle body ( Figure 1 The horizontal movement direction of the grommet G during assembly of the instrument panel DP) shown in the figure (hereinafter referred to as the "grommet assembly direction").

[0049] The grommet G is provided on the outside of the second flexible portion 22 to be described later in the flexible portion 2. Figure 2 The circumferential region indicated by R in the figure is provided with a thick portion 4 in which the second flexible portion 22 is formed thicker than the first flexible portion 21 described later. Preferably, the thick portion 4 extends approximately 45 degrees (circumferential region R) on both sides of the circumference with respect to the grommet assembly direction D.

[0050] In addition, the thick wall portion 4 only needs to be provided on the grommet assembly direction D side, that is, the area in the circumferential region R of the second flexible portion 22 that is closer to the grommet assembly direction D side than the grommet assembly direction orthogonal line V that passes through the center P of the flexible portion 2 and is orthogonal to the grommet assembly direction D. In other words, the formation range of the thick wall portion 4 can be set arbitrarily and does not need to be limited to Figure 2 The range of the circumferential region R is shown.

[0051] Figure 3 The free state of the grommet G is shown, and the Figure 2 The main part of the longitudinal section of the grommet G cut along the AA line is enlarged. Figure 4 The flexible portion 2 is shown in a state where it is bent and deformed when the grommet G is mounted on the vehicle body (instrument panel DP). Figure 2 An enlarged view of the main part of the longitudinal section of the grommet G taken along line AA.

[0052] Especially if Figure 3 As shown in the figure, the flexible portion 2 has: a first flexible portion 21 extending from the other axial end (upper end) of the cylindrical base 1 (the second connecting base 132) toward the radial outer side of the cylindrical base 1; and a second flexible portion 22 extending in a curved shape from the first flexible portion 21 toward the sealing portion 3. That is, the flexible portion 2 is formed so that the first flexible portion 21 and the second flexible portion 22 have a substantially constant wall thickness thinner than the cylindrical base 1, and is bulged outward from the other axial end (upper end) of the cylindrical base 1 toward the radial outer side, so as to be able to bend and deform in the axial direction of the third steering shaft SH3.

[0053] The first flexible portion 21 is Figure 3 As shown in FIG. 1 , in the free state of the grommet G, the grommet G is formed in a horizontal shape with a substantially constant distance from the sealing lip 32, or is formed in a manner such that the distance from the sealing portion 3 (the panel facing surface 311) gradually decreases toward the second flexible portion 22. In other words, the first flexible portion 21 is Figure 3 In the figure, the root portion 210 side connected to the connection base 13 (second connection base 132) is the lowest and is formed horizontally toward the second flexible portion 22 side, or is formed in an inclined shape that gradually rises toward the second flexible portion 22 side.

[0054] The second flexible portion 22 has a cross-sectional arc shape that bulges radially outward from the distal end of the first flexible portion 21 toward the seal portion 3 toward the base portion 310 of the support portion 31, and is disposed at the third steering shaft SH3 (see Figure 1 ) has a bending portion 23 that can be bent in the axial direction at the middle portion in the axial direction. That is, the second flexible portion 22 is configured to be able to bend and deform in the axial direction with the bending portion 23 as a bending point, and is bent and deformed in the axial direction based on the pushing force F acting on the base portion 210 of the first flexible portion 21 from the cylindrical base 1 side, thereby being used as Figure 4 The distal end side of the support portion 31 is pressed toward the instrument panel DP as indicated by the arrow M shown in FIG.

[0055] The sealing portion 3 includes: a support portion 31 extending radially inwardly from the terminal portion of the second flexible portion 22; and a sealing lip 32 protruding from the outer peripheral edge of the support portion 31 and abutting against the vehicle outer side hole edge DP2 of the shaft through hole DP1. That is, the sealing portion 3 elastically contacts the vehicle outer side hole edge DP2 of the shaft through hole DP1 through the elastic force generated by the bending deformation of the flexible portion 2, thereby sealing the vehicle outer side hole edge DP2 of the shaft through hole DP1 to be watertight.

[0056] The support portion 31 is formed into a substantially trapezoidal cross-section, in which the thickness T on the outer peripheral side is the largest and the thickness T gradually decreases from the outer peripheral side toward the inner peripheral side. Figure 3 As shown in the figure, when the grommet G is in a free state, the panel facing surface 311 is substantially parallel to the first flexible portion 21, and when the grommet G is assembled to a vehicle (not shown), the panel facing surface 311 is substantially parallel to the instrument panel DP. Figure 3 As shown, in the free state of the grommet G, it is formed into a tapered shape that is inclined upward from the outer peripheral side toward the inner peripheral side.

[0057] The sealing lip 32 is protrudingly provided at the outer peripheral edge of the panel facing surface 311 of the support portion 31, and is continuously provided in an annular shape over the entire circumferential area of ​​the panel facing surface 311 of the support portion 31. That is, the sealing lip 32 is closely attached to the vehicle outer side hole edge DP2 of the shaft through hole DP1 of the instrument panel DP over the entire circumference, so that the vehicle outer side hole edge DP2 is sealed to be watertight, and the intrusion of moisture or dust from the outside of the vehicle into the vehicle compartment through the vehicle outer side hole edge DP2 can be suppressed.

[0058] In addition, in a predetermined circumferential region R (see Figure 2 ),like Figure 3 , Figure 4 As shown in the figure, a thick wall portion 4 is provided on the outer side of the second flexible portion 22 so as to make the second flexible portion 22 thicker than the first flexible portion 21. The thick wall portion 4 has a substantially constant thickness along the outer side of the second flexible portion 22, is provided integrally with the second flexible portion 22, and extends from the connection portion between the second flexible portion 22 and the first flexible portion 21 to the middle position of the support portion 31.

[0059] More specifically, the thick wall portion 4 is as follows Figure 3 As shown in the figure, the axial end portion, i.e., the lower end portion, of the cylindrical base portion 1 extends to the same position as or lower than the base portion 210 side of the first flexible portion 21, i.e., the connection portion between the second flexible portion 22 and the first flexible portion 21, in the free state of the grommet G. Here, the axial end portion, i.e., the lower end portion, of the thick wall portion 4 is formed to be smoothly continuous along the outer side surface of the first flexible portion 21 (see Figure 3 ).

[0060] On the other hand, the thick wall portion 4 is Figure 3 , Figure 4 As shown in FIG. 1 , the axial end portion of the sealing portion 3, i.e., the upper end portion, extends to the middle position of the outer side of the support portion 31 of the sealing portion 3. More precisely, the upper end portion of the thick wall portion 4 extends to the following position: even if the grommet G falls over during assembly and the inner peripheral side of the support portion 31 is separated from the instrument panel DP (see FIG. 1 ), the thick wall portion 4 is not loose. Figure 5 ), the upper end of the thick-walled portion 4 does not abut against the instrument panel DP.

[0061] (Effects of the present invention)

[0062] Hereinafter, the assembly procedure of the grommet G will be described, and the characteristic effects of the grommet G will also be described.

[0063] For the assembly of the grommet G, first, one end of the grommet G (the mounting base 12 of the cylindrical base 1) through which the third steering shaft SH3 passes is fitted into the gear box cylindrical portion GB1 of the steering gear box GB. Then, the third steering shaft SH3 facing outward is inserted into the shaft through hole DP1 from the sealing portion 3 side, and the other end of the grommet G (the sealing lip 32 of the sealing portion 3) is elastically contacted with the vehicle outer side hole edge DP2 of the shaft through hole DP1. As a result, the grommet G is held in a clamped state between the steering gear box GB and the instrument panel DP, and the grommet G is assembled to the vehicle body together with the steering device.

[0064] At this time, in order to avoid interference with other components installed in the engine compartment of the vehicle, the assembly direction of the grommet G (for example, Figure 1 In other words, sometimes the sealing part 3 cannot be assembled in a manner that the sealing part 3 abuts the instrument panel DP vertically, and the sealing part 3 must be assembled in a manner that the sealing part 3 abuts the instrument panel DP obliquely. In this assembly method, the pushing force F acting on the flexible part 2 acts obliquely relative to the instrument panel DP.

[0065] Here, in the structure of the conventional grommet Gx, Figure 6 As shown in the figure, the wall thickness of the flexible portion 103 is relatively smaller than that of the cylindrical base 100, and the rigidity of the flexible portion 103 side relative to the cylindrical base 100 is relatively lower. Therefore, most of the above-mentioned pushing force F escapes to the outside extending from the flexible portion 103, that is, in the horizontal direction. As a result, the panel parallel component F1 becomes relatively larger than the panel vertical component F2. As a result, it is impossible to obtain a sufficient pushing force (panel vertical component F2) relative to the instrument panel DP. According to the assembly method from the above-mentioned inclined direction, such as Figure 7 As shown in the figure, there is a possibility that the second sealing portion 102 may fall over and turn over.

[0066] In contrast, in the grommet G according to the present embodiment, the thick wall portion 4 provided outside the second flexible portion 22 increases the rigidity of the second flexible portion 22 including the bent portion 23 as the flexible portion on the sealing portion 3 side, and as a result, the rigidity of the first flexible portion 21 as the flexible portion on the cylindrical base 1 side is relatively reduced. As a result, among the pushing force F acting from the cylindrical base 1 side toward the sealing portion 3 side, the panel parallel component F1 parallel to the instrument panel DP is difficult to be transmitted toward the sealing portion 3 side due to the increase in the rigidity of the second flexible portion 22 caused by the thick wall portion 4. On the other hand, the panel perpendicular component F2 perpendicular to the instrument panel DP is easily transmitted toward the sealing portion 3 side due to the relative decrease in the rigidity of the first flexible portion 21. As a result, the panel perpendicular component F2 of the pushing force F acting from the cylindrical base 1 side toward the sealing portion 3 side can be sufficiently ensured.

[0067] Thus, according to the grommet G involved in this embodiment, by providing the thick wall portion 4 on the outside of the second flexible portion 22, among the pushing force F acting from the cylindrical base portion 1 side toward the sealing portion 3 side, the panel parallel component F1 parallel to the instrument panel DP is difficult to transmit, while the panel vertical component F2 perpendicular to the instrument panel DP is easy to transmit. As a result, the panel vertical component F2 becomes relatively large, and the occurrence of rolling due to the overturning of the sealing portion 3 can be suppressed, and the good watertightness obtained by the sealing portion 3 can be ensured.

[0068] In addition, in the grommet G involved in the present embodiment, the thick wall portion 4 is provided only in an area within the circumferential region R of the second flexible portion 22, which is closer to the grommet assembly direction D side than the grommet assembly direction orthogonal line V which passes through the center P of the flexible portion 2 (sealing portion 3) and is orthogonal to the grommet assembly direction D.

[0069] Thus, in the present embodiment, the thick wall portion 4 is provided only in the region of the circumferential region R of the second flexible portion 22 which is closer to the grommet assembly direction D than the orthogonal line V in the grommet assembly direction, that is, in the region where the sealing portion 3 is prone to overturning when the grommet G is installed. Therefore, the rigidity of the second flexible portion 22 is improved only in the circumferential region R of the second flexible portion 22 where the sealing portion 3 is prone to overturning when the grommet G is installed, and the overturning of the sealing portion 3 in the region R can be effectively suppressed.

[0070] In other words, the thick-walled portion 4 is not provided in the circumferential region of the second flexible portion 22 where the sealing portion 3 is less likely to overturn when the ring G is installed, thereby suppressing the unnecessary increase in the rigidity of the second flexible portion 22 in the region and suppressing the occurrence of adverse situations associated with the unnecessary increase in the rigidity of the second flexible portion 22.

[0071] In addition, in the present embodiment, the thick wall portion 4 is formed in such a manner that the axial end portion of the thick wall portion 4 on the cylindrical base portion 1 side is at the same height as the base portion 210 side of the first flexible portion 21 or is lower than the base portion 210 side of the first flexible portion 21 in the self-sealing state of the grommet G. Therefore, there is no possibility that the base portion 210 side of the first flexible portion 21 becomes an undercut during the mold separation when the grommet G is molded, and the moldability of the grommet G can be improved.

[0072] In addition, in a case where the thick-walled portion 4 extends to the axial end portion of the sealing portion 3, when the sealing portion 3 overturns during assembly of the grommet G and the inner circumferential side of the sealing portion 3 separates from the instrument panel DP, the axial end portion of the thick-walled portion 4 on the sealing portion 3 side abuts against the instrument panel DP, and there is a possibility that the overturning of the sealing portion 3 may be further facilitated.

[0073] Therefore, in the grommet G involved in the present embodiment, the thick wall portion 4 is extended to the following position: even if the inner peripheral side of the sealing portion 3 is separated from the instrument panel DP when the grommet G is overturned during assembly, the axial end of the thick wall portion 4 on the sealing portion 3 side does not abut against the instrument panel DP. Therefore, even if the sealing portion 3 is overturned during assembly of the grommet G, the axial end of the thick wall portion 4 on the sealing portion 3 side abuts against the instrument panel DP, thereby suppressing the unfavorable situation that the overturning of the sealing portion 3 is further promoted.

[0074] The present invention is not limited to the structure disclosed in the above-mentioned embodiment. It goes without saying that the detailed structure of the eyelet G, such as the shape of the cylindrical base 1 or the sealing portion 3, which are not directly related to the structure of the present invention, even the shape or size of the parts directly related to the structure of the present invention, such as the thick wall portion 4, can be freely changed according to the specifications of the steering device or vehicle body as the application object without departing from the scope of the concept of the present invention.

[0075] Description of Reference Numerals

[0076] G…Grommet

[0077] 1…cylindrical base

[0078] 2…Flexible part

[0079] 21…1st flexible portion

[0080] 22…Second flexible portion

[0081] 23…Bending part

[0082] 3…Seal

[0083] 4…Thick wall part

[0084] DP…Dashboard

[0085] SH…Steering shaft

Claims

1. A grommet, It is characterized in that The above-mentioned grommet has: a cylindrical base portion having a cylindrical shape and covering an outer peripheral side of a steering shaft, wherein the steering shaft passes through a shaft through-hole provided through a dashboard of a vehicle body that separates a vehicle compartment from an engine compartment; a flexible portion extending in a curved shape from an axial end portion of the cylindrical base toward the radially outer side and capable of axially bending in a manner of bulging toward the radially outer side of the cylindrical base; and a sealing portion, which is provided at the distal end of the flexible portion and abuts against the vehicle outer side hole edge of the shaft through hole when the flexible portion is assembled to the vehicle body; The flexible portion includes a first flexible portion and a second flexible portion, wherein the first flexible portion extends from an axial end of the tubular base toward the radially outer side of the tubular base, and the second flexible portion extends from the first flexible portion toward the sealing portion in a curved shape and includes a bending portion that can be bent in the axial direction. A thick wall portion is provided on the outer side of the second flexible portion so as to make the second flexible portion thicker than the first flexible portion. The grommet is assembled in such a manner that the sealing portion abuts against the instrument panel at an angle. The thick wall portion is provided only in a region of the second flexible portion in the circumferential direction that is closer to the grommet assembling direction side than an assembling direction orthogonal line that passes through the center of the sealing portion and is orthogonal to the grommet assembling direction.

2. The grommet according to claim 1, It is characterized in that The thick wall portion is formed in such a manner that, in the free state of the grommet, an axial end portion of the thick wall portion on the cylindrical base side is at the same height as or lower than the base side of the first flexible portion.

3. The grommet according to claim 1, It is characterized in that The thick portion extends to a position where an axial end portion of the thick portion on the sealing portion side does not abut against the instrument panel even if the inner peripheral side of the sealing portion falls over and separates from the instrument panel during assembly of the grommet.

Images