JP4212163B2 - Steering shaft dust seal structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dust seal structure for a steering shaft of a vehicle.
[0002]
[Prior art]
An example of a dust seal for a steering shaft is described in Japanese Utility Model Laid-Open No. 2-138278. This includes an inner sliding contact ring that is in sliding contact with the outer surface of the steering shaft, an outer fixing ring that is fixed to the column cover, and a rubber-made deforming portion that is interposed between the two rings. The inner slidable contact ring includes a lip that is slidably contacted with the steering shaft, a hollow portion that stores grease, and a grease dropping hole that leads from the hollow portion to the lip tip surface, and the slidable contact surface between the lip and the steering shaft is lubricated with grease. It is like that.
[0003]
[Problems to be solved by the invention]
In the case of the above prior art, although the sliding contact surface between the lip and the steering shaft is lubricated by grease, it is surely prevented that the outer surface of the shaft and the lip rub against each other when the steering shaft rotates to generate noise. Is difficult. In particular, when the dust seal is assembled to the vehicle body together with the steering shaft, the positional relationship between the shaft and the dust seal may shift in a direction perpendicular to the shaft due to dimensional errors or assembly errors. Uneven rotation of the steering shaft is a problem.
[0004]
Although the above-mentioned misalignment is absorbed to some extent by the rubber deformed portion of the dust seal, there is a situation in which the absorption capacity is increased, that is, the rubber deformed portion cannot be thinned. In other words, in the conventional structure, it is necessary to make the lip relatively strong against the steering shaft (tightly fitted) in order to ensure sealing performance, but if the rubber deformed part is thin, the steering shaft will rotate. When the lip is dragged to the shaft, the lip rotates together with the shaft while the rubber deformation portion is twisted, and the twisting sound is easily generated. Therefore, it is necessary to thicken the rubber deformed portion to prevent its twisting.
[0005]
However, the fact that the rubber deformed portion has to be thick in this way is disadvantageous in absorbing the displacement. Therefore, when the positional deviation is present, the lip may be deformed to cause so-called one-side contact that does not contact the outer surface of the steering shaft with an equal force. For this reason, the rotation unevenness of the steering shaft is generated, or a large abnormal noise is generated due to rubbing at the portion where the lip strongly hits the shaft. In addition, a gap may be formed between the lip and the shaft on the opposite side of the portion where the lip strongly hits the shaft, and dust or sound may easily enter the vehicle interior.
[0006]
That is, it is an object of the present invention to reliably prevent the intrusion of dust and sound, reliably prevent abnormal noise during rotation of the steering shaft, and reliably absorb misalignment during assembly.
[0007]
[Means for Solving the Problems]
The present invention is intended to solve such problems by effectively using a viscous material such as grease as a seal that prevents the intrusion of dust and sound, rather than merely as a lubrication.
[0008]
The invention according to claim 1 includes an inner annular body that has a fitting hole into which a steering shaft is fitted and rotates together with the steering shaft;
An outer annular body that is fixed directly or via a cylindrical member to the opening peripheral edge of the dash panel of the vehicle,
An annular groove is formed in one of the two annular bodies and is formed in an annular shape so as to go around the steering shaft, and is filled with a viscous body,
The other of the two annular bodies, both said relative rotation of the annular member over the entire periphery to permit Ri Hama Visco body of the annular groove, said one annular body and the annular groove so as not Sureawa It is a dust seal structure of a steering shaft provided with an annular seal portion that moves relatively in a state of being enclosed in a viscous body.
[0009]
That is, in this dust seal structure, the lip is slidably contacted with the outer surface of the steering shaft to ensure the sealing performance against dust and sound, but the inner annular body fitted to the steering shaft and the outer annular body fixed to the dash panel. The sealing property is secured by the viscous body interposed between the two. When the steering shaft rotates, the annular seal portion moves relative to the annular groove in a state of being wrapped in a viscous body, so that the problem of abnormal noise due to friction is solved.
[0010]
Here, “viscous body” is generally defined as having an intermediate property between solid and liquid, but in the present invention, it may be a fluid having a viscosity that does not flow out of the annular groove. Is preferred.
[0011]
The invention according to claim 2 is the dust seal structure of the steering shaft according to claim 1,
The inner annular body has an annular groove opened on its outer peripheral surface,
The outer annular body is fixed to the peripheral edge of the opening of the dash panel of the vehicle directly or via a cylindrical member, and the two annular bodies are relatively disposed in the viscous body of the annular groove of the inner annular body. It has an annular seal portion on the inner periphery side that fits over the entire circumference so as to allow rotation and relative movement in the radial direction, and a bellows-like rubber portion that connects the annular fixing portion and the annular seal portion.
[0012]
In this invention, the annular seal portion of the outer annular body is fitted to the viscous body of the annular groove of the inner annular body to allow not only relative rotation of both annular bodies but also movement in the radial direction. Sometimes even if there is a radial misalignment between the two annular bodies, this misalignment can be absorbed by the relative displacement in the radial direction between the two annular bodies while ensuring the sealing performance by the viscous body, and the steering It is possible to reliably prevent the generation of abnormal noise when the shaft rotates. Further, the bellows-like rubber portion absorbs a displacement in the axial direction of the steering shaft due to the deformation thereof.
[0013]
Further, in the present invention, the sealing property is secured by the viscous body, and it is not necessary to strongly apply the annular seal portion to the inner surface of the annular groove of the inner annular body. Even if the hit occurs, rotation unevenness of the steering shaft does not occur, and abnormal noise during rotation of the shaft can be avoided. In addition, since the problem that the annular seal portion is dragged and rotated when the steering shaft rotates is eliminated, the bellows-like rubber portion can be made thin so that it can be easily deformed, and the displacement in the axial direction can be absorbed. Become advantageous.
[0014]
The invention according to claim 3 is the dust seal structure of the steering shaft according to claim 1,
An outer peripheral annular fixing portion in which the outer annular body is fixed directly or via a cylindrical member to an opening peripheral portion of a dash panel of a vehicle, and an inner peripheral annular groove portion having an annular groove opened on an inner peripheral surface; And an accordion rubber portion connecting the annular fixing portion and the annular groove portion,
The inner annular body has an annular seal portion that protrudes outward in the radial direction and fits over the entire circumference so as to allow relative rotation and relative movement in the radial direction of the annular bodies in the viscous body of the annular groove of the outer annular body. That's it.
[0015]
That is, the present invention is such that the arrangement relationship between the annular seal portion and the annular groove is opposite to that of the invention according to claim 2, and has the same functions and operations as the invention according to claim 2. Have.
[0016]
The invention according to claim 4 is the dust seal structure of the steering shaft according to claim 2 or 3,
The annular seal portion is a plate-like body extending in the radial direction, and has a protrusion extending in the circumferential direction and a protrusion extending in the radial direction in the vicinity of the opening of the annular groove on the plate surface. .
[0017]
That is, if the annular seal portion is repeatedly rotated and moved in the viscous body of the annular groove, a gap is likely to be generated at the interface between the annular seal portion and the viscous body. Therefore, in the present invention, the radial ridges are provided, and the viscous body is caused to flow by the radial ridges during the rotational movement so that the gap is not generated. Further, the protrusion extending in the circumferential direction prevents the viscous body from scattering from the annular groove.
[0018]
The invention according to claim 5 is the dust seal structure of the steering shaft according to claim 1,
The inner annular body has an annular groove opened in one of the axial directions of the steering shaft;
The outer annular body is fixed to the peripheral edge of the opening of the dash panel of the vehicle directly or via a cylindrical member, and the two annular bodies are relatively disposed in the viscous body of the annular groove of the inner annular body. It has a cylindrical annular seal part on the inner circumference side that fits from the axial direction over the entire circumference so as to allow rotation and relative movement in the axial direction, and a bellows-like rubber part that connects the annular fixing part and the annular seal part. That's it.
[0019]
In the case of this invention, the annular seal portion of the outer annular body is fitted to the viscous body of the annular groove of the inner annular body so as to allow not only relative rotation of both annular bodies but also movement in the axial direction. Even if an axial displacement occurs between the inner and outer annular bodies, the positional displacement can be absorbed by the relative displacement in the axial direction between both annular bodies while securing the sealing property by the viscous body, In addition, it is possible to reliably prevent the generation of noise during shaft rotation. Moreover, the said bellows-like rubber part absorbs the position shift of the said radial direction by the deformation | transformation.
[0020]
【The invention's effect】
According to the first aspect of the present invention, the periphery of the steering shaft is circulated around one of the inner annular body that fits and rotates with the steering shaft and the outer annular body that is fixed to the dash panel of the vehicle. An annular groove formed in a ring and filled with a viscous body is formed, and the other of the annular bodies is fitted in the viscous body of the annular groove over the entire circumference so as to allow relative rotation of the annular bodies , Since there is an annular seal part that moves relative to the annular groove so that it does not rub against the one annular body, the adhesive between the annular bodies rubs when the steering shaft rotates. Intrusion of dust and sound can be surely prevented while preventing the generation of abnormal noise.
[0021]
According to the second or third aspect of the invention, the outer annular body is provided with the bellows-like rubber part, and the annular seal part is allowed to move in the annular groove in the radial direction as well as the relative rotation of both annular bodies. Even if a radial misalignment occurs between the two annular bodies, the steering shaft rotates by absorbing the misalignment by the relative displacement in the radial direction between the two annular bodies while ensuring the sealing performance by the viscous body. Occurrence of abnormal noise at the time can be surely prevented, and axial position shift absorbability by the bellows-like rubber portion can be enhanced.
[0022]
According to the invention which concerns on Claim 4, since the said annular seal part has the protrusion extended in the circumferential direction and the protrusion extended in radial direction in the opening part vicinity of the said annular groove, the interface of an annular seal part and a viscous body It is possible to prevent a gap from being formed in the annular groove and to prevent the viscous body from scattering from the annular groove.
[0023]
According to a fifth aspect of the present invention, the inner annular body has an annular groove opened in one of the axial directions of the steering shaft, and the outer annular body is fixed to the dash panel of the vehicle. A cylindrical annular seal portion that enters the entire body of the annular groove of the inner annular body so as to allow relative rotation and relative movement in the axial direction of the annular bodies, and the annular fixing portion and the annular seal. Since it has a bellows-like rubber part that connects the parts, it is possible to reliably prevent the intrusion of dust and sound while preventing the generation of abnormal noise due to rubbing during rotation of the steering shaft by the viscous body between both annular bodies, Moreover, the axial displacement between the two annular bodies can be absorbed by the relative displacement in the axial direction between the two annular bodies, and the radial displacement of the two annular bodies can be absorbed by the deformation of the bellows-like rubber portion. .
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0025]
<Embodiment 1>
This embodiment is shown in FIGS. In FIG. 1, 1 is a steering shaft of a vehicle, 2 is a dash panel, 3 is an inner annular body that has a fitting hole into which the steering shaft 1 is fitted, and 5 rotates along with the steering shaft 1. It is an outer annular body fixed through an inner cover member 8a and a cylindrical outer cover member 8b.
[0026]
The inner cover member 8a is made of rubber or resin, the outer cover member 8b is made of metal or resin, and is fitted to the inner cover member 8a, and the flange at one end of both is the peripheral edge of the opening 2a of the dash panel 2 It is fixed to the part without a gap. The outer annular body 5 is fitted in the inner cover member 8a, and the outer annular body 5 and the inner and outer cover members 8a and 8b are fastened and coupled by a band 8c wound around the outer cover member 8b. .
[0027]
As shown in FIG. 2, the inner annular body 3 is composed of first and second annular members 6 and 7 made of metal or resin. The first annular member 6 includes a cylindrical portion having a fitting hole 4 into which the steering shaft 1 is fitted, and an annular plate portion projecting radially outward from one end of the cylindrical portion. The second annular member 7 includes a cylindrical portion that is shorter than the cylindrical portion of the first annular member 6 and an annular plate portion that protrudes radially outward from one end of the cylindrical portion. The two annular members 6 and 7 are integrally formed by fitting the cylindrical portion of the second annular member 7 to the end of the cylindrical portion of the first annular member 6 on the side opposite to the annular plate portion without a gap.
[0028]
In the inner annular body 3, an annular groove 9 is formed between the annular plate portions of the annular members 6 and 7 in the outer peripheral surface, and the annular groove 9 is filled with a viscous body 10 such as grease. The steering shaft 1 is press-fitted into the fitting hole 4 of the first annular member 6 so as to rotate integrally with the inner annular body 3.
[0029]
The outer annular body 5 enters the outer peripheral metal or resin annular fixing member 11 fitted in the inner cover member 8 a and the inner peripheral side of the inner annular body 3 in the viscous body 10 of the annular groove 9. An annular seal member 12 and a bellows-like rubber member 13 connecting the annular fixing member 11 and the annular seal member 12 are configured.
[0030]
The annular fixing member 11 is formed in a cylindrical shape having a flange projecting outward at one end, and the flange is fixed to the peripheral portion of the opening 2 a for allowing the steering shaft 1 of the dash panel 2 to pass therethrough without any gap. As shown in FIGS. 3 and 4, the annular seal member 12 includes a metal or resin-made annular plate 14 that spreads in the radial direction, and a rubber 15 that is fixed to both surfaces of the annular plate 14 by molding, It is fitted in the viscous body 10 of the annular groove 9 of the inner annular body 3 over the entire circumference so as to allow relative rotation and relative movement in the radial direction of the annular bodies 3 and 5.
[0031]
The rubber 15 of the annular seal member 12 includes protrusions 15a and 15b extending in the circumferential direction in the vicinity of the opening of the annular groove 9 of the inner annular body 3 and in the vicinity of the inner peripheral part of the annular plate in the annular plate 14, and the protrusion 15a. , 15b, and a plurality of protrusions 15c extending in the radial direction. Further, a through hole 14 a penetrating through the annular plate 14 is formed in a portion of the annular plate 14 between the protrusions 15 a and the protrusions 15 b.
[0032]
The bellows-like rubber member 13 is formed in a ripple shape in which a plurality of wave rings are concentrically formed, and an outer peripheral portion thereof is an end portion on the opposite side to the flange of the annular fixing member 11 and an inner peripheral portion thereof. Are fixed to the outer peripheral portion of the annular seal member 12 by molding over the entire circumference.
[0033]
Therefore, in this embodiment, the sealing property against dust and sound is ensured by the viscous body 10, and when the steering shaft 1 rotates, the annular seal member 12 of the outer annular body 5 forms the annular groove 9 of the inner annular body 3. Since it relatively rotates in a state of being wrapped in the viscous body 10, the problem of generation of abnormal noise due to friction between members is eliminated. Further, when the steering shaft 1 is assembled to the dash panel 2 via the inner annular body 3 and the outer annular body 5, even if the radial positional deviation occurs between the annular bodies 3, 5, the inner annular body As long as the three annular grooves 9 and the annular seal member 12 of the outer annular body 5 are displaced relative to each other in the radial direction, the displacement is absorbed and the annular seal member 12 is fitted in the viscous body 10 of the annular groove 9. The sealing property is ensured, and the steering shaft 1 can also rotate without generating abnormal noise.
[0034]
Further, the circumferential protrusion 15a of the annular seal member 12 in the vicinity of the opening of the annular groove 9 contributes to prevention of scattering of the viscous body 10 in the annular groove 9, and the radial protrusion 15c is when the steering shaft 1 rotates. The viscous body 10 is caused to flow to prevent the formation of a gap at the interface between the viscous body 10 and the annular seal member 12. Further, the through hole 14 a allows the viscous body 10 on both sides of the annular seal member 12 to go back and forth, and improves the adhesion of the viscous body 10 to the annular seal member 12.
[0035]
The axial displacement that may occur between the inner annular body 3 and the outer annular body 5 is absorbed by the deformation of the bellows-like rubber member 13 of the outer annular body 5. When such a displacement occurs, for example, as shown in FIG. 3, the inner and outer ridges 15 a and 15 b of the annular seal member 12 come into contact with the inner surface of the annular groove 9 in the inner annular body 3. Since a viscous body exists around 15b, it is possible to avoid generating abnormal noise when the steering shaft 1 rotates.
[0036]
Further, as long as the annular seal member 12 is fitted in the viscous body 10 over the entire circumference, the sealing performance is ensured. Therefore, it is not necessary to strongly apply the annular seal member 12 to the inner surface of the annular groove of the inner annular body 3, as shown in FIG. There is no problem of uneven rotation and abnormal noise even when the single contact state is shown. Moreover, since it is not necessary to make the bellows-like rubber member 13 thick, that is, it can be made thin, the axial misalignment absorbability is also increased, and this increases the one-piece contact. It works favorably in avoiding.
[0037]
FIG. 5 shows a modified example of the annular seal member 12, which is characterized in that the annular plate 14 is wrapped by a rubber 15, and the others are the same as those shown in FIGS. Yes, like elements are given the same reference numerals.
[0038]
<Embodiment 2>
This embodiment is shown in FIG. 6, and unlike the first embodiment, an annular seal portion 12 is formed on the inner annular body 3, and an annular groove 9 for filling the viscous body 10 is formed on the outer annular body 5. Yes.
[0039]
That is, the inner annular body 3 includes a cylindrical portion 16 having a steering shaft fitting hole 4, and a plate-shaped annular seal portion 12 projects radially outward from the center of the cylindrical portion 16.
[0040]
The outer annular body 5 includes an annular fixing member 11 similar to that of the first embodiment, an annular groove member 17 having an annular groove 9 opened on the inner peripheral surface, and an accordion shape connecting the annular fixing member 11 and the annular groove member 17. The rubber member 13 is used. The annular groove member 17 includes an annular plate portion that extends in the radial direction, a peripheral wall portion that protrudes in the axial direction from the periphery of the annular plate portion, and a flange that protrudes radially outward from the protruding end of the peripheral wall portion. A pair of annular members 18, 18 are combined with each other at the flange portion, and an annular groove 9 opened on the inner peripheral surface of the annular groove member 17 is formed between the opposed annular plate portions. The bellows-like rubber member 13 has an inner peripheral edge portion connected to the flange of the annular groove member 17.
[0041]
Thus, the plate-like annular seal portion 12 of the inner annular body 3 is fitted over the entire circumference in the viscous body 10 filled in the annular groove 9 of the outer annular body 5. The annular seal portion 12 is provided with a rubber 15 and a through hole 14a as in the first embodiment.
[0042]
Therefore, this embodiment is different from the first embodiment only in the disposition relationship between the annular seal portion and the annular groove, and thus has the same effects as the first embodiment.
[0043]
<Embodiment 3>
This embodiment is shown in FIG. 7 and is characterized in that the annular groove 9 of the inner annular body 3 is opened in the axial direction.
[0044]
That is, the inner annular body 3 is formed by connecting one end of an inner cylindrical portion and an outer cylindrical portion provided concentrically by an annular plate portion, and the annular groove 9 is formed between the inner and outer cylindrical portions. .
[0045]
The outer annular body 5 includes an annular fixing member 11 and a bellows-like rubber member 13 similar to those of the first embodiment. The annular seal member 12 connected to the inner peripheral edge of the bellows-like rubber member 13 is a cylindrical portion. And a flange projecting outward from one end of the cylindrical portion, the cylindrical portion is fitted to the viscous body 10 of the annular groove 9 from the axial direction over the entire circumference, and the flange is coupled to the bellows-like rubber member 13. . On both surfaces of the annular seal member 12, a circumferential ridge extending in the circumferential direction in the vicinity of the opening of the annular groove 9 and the vicinity of the tip of the annular seal member 12, and the axial direction so as to connect both the circumferential ridges A rubber 15 having an axial ridge extending in the direction is provided. Further, a through hole 14 a is provided in a portion surrounded by each protrusion of the annular seal member 12.
[0046]
Therefore, in this embodiment, the annular seal member 12 of the outer annular body 5 allows the viscous body 10 of the annular groove 9 of the inner annular body 3 to move in the axial direction as well as the relative rotation of the annular bodies 3 and 5. Therefore, when an axial displacement occurs between the inner and outer annular bodies 3 and 5 when assembled to the dash panel 2, this axial position is secured while the sealing property is secured by the viscous body 10. The deviation can be absorbed by the relative displacement in the axial direction between the annular bodies 3 and 5. On the other hand, the bellows-like rubber member 13 absorbs the positional deviation in the radial direction of the annular bodies 3 and 5 by the side diameter.
[0047]
Further, the circumferential ridge existing in the vicinity of the annular groove opening of the rubber 15 of the annular seal member 12 contributes to the prevention of scattering of the viscous body of the annular groove 9, and the axial ridge is the viscous body 10 when the steering shaft 1 rotates. To prevent a gap from being generated at the interface between the viscous body 10 and the annular seal member 12, and the through hole 14 a improves the adhesion of the viscous body 10 to the annular seal member 12.
[0048]
In the first to third embodiments, the bellows-like rubber member 13 has a ripple shape and spreads in a plane in the radial direction, but may be a cylindrical bellows shape.
[0049]
In the first to third embodiments, the annular fixing member 11 of the outer annular body 5 is made of metal or resin that is separate from the bellows-like rubber member 13, and is integrally formed with the bellows-like rubber member 13. It may be made of rubber. In that case, the annular fixing portion made of rubber is extended to the peripheral edge of the opening of the dash panel 2 and applied to the peripheral edge of the opening, and an annular presser plate is overlaid thereon, and the presser plate is attached to the dash panel by a screw member or the like. You may make it tighten to. That is, in this case, the outer annular body 5 is directly fixed to the dash panel, and the cylindrical cover members 8a and 8b are unnecessary.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a structure for attaching a steering shaft to a dash panel according to Embodiment 1 of the present invention.
FIG. 2 is a longitudinal sectional view showing a dust seal structure of a steering shaft according to the embodiment.
FIG. 3 is a cross-sectional view showing an annular groove portion of the same form.
FIG. 4 is a front view showing an annular seal member of the same form.
FIG. 5 is a cross-sectional view showing another example of the annular seal member of the same form.
FIG. 6 is a longitudinal sectional view showing a dust seal structure of a steering shaft according to Embodiment 2 of the present invention.
FIG. 7 is a longitudinal sectional view showing a dust seal structure of a steering shaft according to Embodiment 3 of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Steering shaft 2 Dash panel 2a Opening 3 Inner annular body 4 Fitting hole 5 Outer annular body 6,7 Annular member 9 Annular groove 10 Viscous body 11 Annular fixing member 12 Annular seal member 13 Bellows rubber member 14 Annular plate 14a Through hole 15 Rubber 15a,
15b Circumferential ridge 15c Radial ridge 16 Cylindrical portion 17 Annular groove member

Claims (5)

An inner annular body having a fitting hole into which the steering shaft is fitted and rotating together with the steering shaft;
An outer annular body that is fixed directly or via a cylindrical member to the opening peripheral edge of the dash panel of the vehicle,
An annular groove is formed in one of the two annular bodies and is formed in an annular shape so as to go around the steering shaft, and is filled with a viscous body,
The other of the two annular bodies, both said relative rotation of the annular member over the entire periphery to permit Ri Hama Visco body of the annular groove, said one annular body and the annular groove so as not Sureawa A dust seal structure for a steering shaft provided with an annular seal portion that moves relative to the inside in a state of being wrapped in a viscous body. The inner annular body has an annular groove opened on its outer peripheral surface,
The outer annular body is fixed to the peripheral edge of the opening of the dash panel of the vehicle directly or via a cylindrical member, and the two annular bodies are relatively disposed in the viscous body of the annular groove of the inner annular body. The steering shaft according to claim 1, further comprising: an inner circumferential annular seal portion that is fitted over the entire circumference so as to allow rotation and relative movement in the radial direction; and a bellows-shaped rubber portion that connects the annular fixing portion and the annular seal portion. Dust seal structure. An outer peripheral annular fixing portion in which the outer annular body is fixed directly or via a cylindrical member to an opening peripheral portion of a dash panel of a vehicle, and an inner peripheral annular groove portion having an annular groove opened on an inner peripheral surface; And an accordion rubber portion connecting the annular fixing portion and the annular groove portion,
The inner annular body has an annular seal portion that protrudes outward in the radial direction and fits over the entire circumference so as to allow relative rotation and relative movement in the radial direction of the annular bodies in the viscous body of the annular groove of the outer annular body. The dust seal structure for a steering shaft according to claim 1.   The said annular seal part is a plate-shaped body extended in radial direction, and has the protrusion extended in the circumferential direction and the protrusion extended in radial direction on the plate surface in the vicinity of the opening part of the said annular groove. Item 4. A dust seal structure for a steering shaft according to Item 3. The inner annular body has an annular groove opened in one of the axial directions of the steering shaft;
The outer annular body is fixed to the peripheral edge of the opening of the dash panel of the vehicle directly or via a cylindrical member, and the two annular bodies are relatively disposed in the viscous body of the annular groove of the inner annular body. A cylindrical annular seal portion on the inner peripheral side that is fitted from the axial direction over the entire circumference so as to allow rotation and relative movement in the axial direction, and a bellows-shaped rubber portion that connects the annular fixed portion and the annular seal portion. Item 2. A dust seal structure for a steering shaft according to Item 1.

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